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Calcareous nannofossil biostratigraphy: historical background and application in Cenozoic chronostratigraphy

May 2017
Lethaia 50(3)

May 2017
50(3)

DOI:10.1111/let.12218

Authors:

Claudia Agnini

University of Padova

Simonetta Monechi

University of Florence

Isabella Raffi

Università degli Studi G. d'Annunzio Chieti e Pescara

Calcareous nannofossils are considered one of the most powerful biostratigraphical tool in marine carbonate sediments especially in open ocean settings. Their origination goes at least as far back as the Triassic (ca. 220 Ma) when they first biomineralized and produced calcite skeletons. Since then, they have evolved rapidly showing widespread biogeographical distributions. Starting from the 1950s, changes in calcareous nannofossil assemblages have been used to date rocks and sediments and a fundamental step was achieved two decades later with the publication of the first comprehensive biostratigraphical schemes. Standardized quantitative counting methods, unambiguous taxonomy as well as highly resolved data sets provide high-quality biostratigraphical datums which, in turn, result in the precise positioning of calcareous nannofossil biohorizons and in the construction of reliable biostratigraphical frameworks. Here, we use recently published Cenozoic biozonations as a framework to present an overview of the calcareous nannofossil biohorizons which are used in chronostratigraphy to denote Cenozoic Global Standard Stratotype-section and Point.

High-resolution A, and low-resolution B, abundance patterns of Species A. The aliasing effect is particularly evident in the lowresolution data set where the signal is completely distorted by the loss of information. The sampling resolution is of 10 cm in A and of 100 cm in B. Biohorizons are positioned at the mid-points.

…

Neogene calcareous nannofossil biozonation (modified from Backman et al. 2012): CP (Okada & Bukry 1980), NP (Martini 1971), CN (Backman et al. 2012). The Geomagnetic Polarity Time Scale (GPTS) is from Lourens et al. (2004). Grey box and dashed lines show the uncertainty in defining biozone boundaries. Biochronology is after Backman et al. (2012). On the right, images of CN stage index-species are taken from literature (see Appendix S1 for details). * = Base; + = Top; x = crossover; ° = acme end. [Colour figure can be viewed at wileyonlinelibrary.com]

…

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Calcareous nannofossil biostratigraphy: historical

background and application in Cenozoic chronostratigraphy

CLAUDIA AGNINI , SIMONETTA MONECHI AND ISABELLA RAFFI

Agnini, C., Monechi, S. & Rafﬁ, I. 2017: Calcareous nannofossil biostratigraphy:

historical background and application in Cenozoic chronostratigraphy. Lethaia , Vol.

50, pp. 447–463.

Calcareous nannofossils are considered one of the most powerful biostratigraphical

tool in marine carbonate sediments especially in open ocean settings. Their origination

goes at least as far back as the Triassic (ca. 220 Ma) when they ﬁrst biomineralized

and produced calcite skeletons. Since then, they have evolved rapidly showing wide-

spread biogeographical distributions. Starting from the 1950s, changes in calcareous

nannofossil assemblages have been used to date rocks and sediments and a fundamen-

tal step was achieved two decades later with the publication of the ﬁrst comprehensive

biostratigraphical schemes. Standardized quantitative counting methods, unambigu-

ous taxonomy as well as highly resolved data sets provide high-quality biostratigraphi-

cal datums which, in turn, result in the precise positioning of calcareous nannofossil

biohorizons and in the construction of reliable biostratigraphical frameworks. Here,

we use recently published Cenozoic biozonations as a framework to present an over-

view of the calcareous nannofossil biohorizons which are used in chronostratigraphy

to denote Cenozoic Global Standard Stratotype-section and Point. □Biostratigraphy,

Calcareous nannofossils, Cenozoic, chronostratigraphy, Global Stratotype Standard-sec-

tion and Point.

Claudia Agnini ✉[claudia.agnini@unipd.it], Dipartimento di Geoscienze, Universit

degli Studi di Padova, Via Gradenigo 6, I-35131 Padova, Italy; Simonetta Monechi

[simonetta.monechi@uniﬁ.it], Dipartimento di Scienze della Terra, Universit

a degli Studi

di Firenze, Via LaPira 4, I-50121 Firenze, Italy; Isabella Rafﬁ [isabella.rafﬁ@unich.it],

Dipartimento di Ingegneria e Geologia, Universit

a ‘G. D’Annunzio’ di Chieti-Pescara,

Via dei Vestini 31, I-66100 Chieti Scalo, Italy; manuscript received on 13/01/2017;

manuscript accepted on 15/03/2017.

The ﬁrst recognition of calcareous nannofossils/coc-

coliths went back to 1836, when Christian G. Ehren-

berg described these peculiar ‘morpholites’ and/or

‘Kalkerdige Crystalldrusen’ from a Cretaceous chalk

cropping out in the R€

ugen Island in the Baltic Sea. He

did not grasp their organic nature and was convinced

that they were rather concretions than microfossils.

After this very important discovery, in 1858, Tho-

mas H. Huxley described the coccolithophores as

‘...a multitude of very curious rounded bodies, to

all appearance consisting of several concentric layers,

surrounding a minute clear centre, and looking, at

ﬁrst sight, somewhat like single cells of the plant Pro-

tococcus; as these bodies, however, are rapidly and

completely dissolved by dilute acids, they cannot be

organic, and I will, for convenience sake, simply call

them coccoliths (Fig. 1)...’ Three years later in

addition to the coccoliths noted by Huxley, Wallich

discovered peculiar spheroidal bodies, which he

terms ‘coccospheres’ and proposed that the coccol-

iths proceed from the coccospheres (Huxley 1858;

Wallich 1861). In the same year, 1861, Henry C.

Sorby also published a paper describing the coccol-

iths he found in the English Chalk. Since then, coc-

coliths have been considered organic in nature but

their importance in rock dating and their role in the

biogeochemical cycles were too far away to be

understood so that coccoliths/nannoliths would

have remained only a scientiﬁc curiosity for many

years.

After the HMS Challenger Expedition (1872–76),

Murray & Blackman (1898) published a pivotal

study on the biology and biogeography that was fol-

lowed shortly after by the work of Lohmann (1902),

who recognized the presence of ﬂagella and ﬁrst

introduced the term ‘nannoplankton’. Once these

peculiar organisms started to be widely studied, sci-

entists soon realized that they present very different

structures and shapes, which allowed the deﬁnition

of taxonomic groups based on shared characteristics.

However, the complex heteromorphic cycle (poly-

morphism), the changes forced by external environ-

mental conditions (ecophenotypy) and the

diagenetic alterations (preservation) could instead

make their classiﬁcation (parataxonomy) difﬁcult

and the species concept somewhat ambiguous.

The next step was the recognition that each taxon

has a unique distribution in space and time. Their

stratigraphical importance became progressively evi-

dent to the geological community starting from the

mid-part of the last century, following a landmark

publication that evidenced for the ﬁrst time their

application in biostratigraphy and rock dating

(Bramlette & Riedel 1954). This benchmark work,

though based on little taxonomic work and data,

and possibly biased by technical difﬁculties, was still

able to enlighten that coccoliths are common in

some Mesozoic and Cenozoic rocks, especially in

deep-sea deposits, and may constitute the main bulk

of the chalky sediments. The ﬁrst stratigraphical dis-

tribution of calcareous nannofossil taxa, what is

called a range chart, was in fact provided by these

authors and represented a fundamental starting

point for the development of the calcareous nanno-

fossil biostratigraphy.

Subsequently, availability of deep-sea sediments

and cores, provided by ocean research drillings, facil-

itated the studies on nannoplankton and nannofos-

sils and, in turn, expanded their importance as

stratigraphical and chronological tool. Moreover, it

became evident that they played also an important

role in the bio-geosphere history and therefore they

could be used to reconstruct palaeoenvironmental/

oceanographic conditions in the geological past.

The geological history of nannoplankton is inti-

mately related to two other planktonic microfossil

groups: dinoﬂagellates and diatoms. These three new

groups entered the fossil record in the Triassic (Falk-

owski et al. 2004; De Vargas et al. 2007). The inven-

tion of the biomineralization by nannoplankton and

their related fossil remains represented an important

step in the evolution of the whole marine ecosystem

and a signiﬁcant change in pelagic sedimentation

and biogenic carbonate production. Their appear-

ance in the Triassic was a breakthrough in the ocean

realm, speciﬁcally for the marine carbonate system

and the global carbon cycle.

In the modern ocean, calcareous nannoplankton

together with dinoﬂagellates and diatoms play a

major role in export ﬂux of organic matter to the

ocean interior and sediments but we would empha-

size that they are also responsible of the majority of

the carbonate production and export in the ocean

(Milliman 1993; Falkowski et al. 2004). The Meso-

zoic was the time when this group, together with

planktonic foraminifera, acted to shift the primary

site of carbonate production from shallow water

environments to the open ocean (Brownlee & Taylor

2004; Hay 2004).

Approximately 220 My ago, calcareous nanno-

plankton started to produce mineralized skeletons

and evolved while interacting with changes in cli-

mate, ocean structure and chemistry as well as in the

geosphere. Increases in biodiversity and rates of evo-

lution occurred through the Jurassic and Cretaceous

and continued in the Cenozoic (Fig. 2), and the

fairly fast evolutionary changes resulted in several

ﬁrst and last appearance events that represent the

basis for detailed biostratigraphical schemes, suc-

cessfully applied in different intervals of geological

time.

Studies published during the last decades have

demonstrated that the applications of calcareous

nannofossils comprehend the ﬁelds of biostratigra-

phy and biochronology, and expands into palaeo-

ceanography and palaeobiology. Here, we focus on

their trait as excellent stratigraphical and chrono-

logic markers in marine sediments and underline

their pivotal role as correlation tool involved in

chronostratigraphical issues.

Calcareous nannofossil

biostratigraphy (and biochronology)

Calcareous nannofossils have undeniable qualities

when used in biostratigraphy. First, they are usually

abundant in marine sediments and this implies that

1 μm

Fig. 1. Coccosphere of Helicosphaera carteri (Wallich 1877) Kamptner, 1954. A, Huxley’s drawing (1858); B, SEM image (Young et al.

2003). [Colour ﬁgure can be viewed at wileyonlinelibrary.com]

448 Agnini et al. LETHAIA 50 (2017)

they constitute one of the most important and con-

tinuous palaeontological record, at least for the last

220 Myr. Secondly, deriving from planktonic organ-

isms, their taxa overall display extensive biogeo-

graphical distributions (cosmopolitan), which is an

indisputable beneﬁt if one tries to correlate the same

stratigraphical level over wide areas. Moreover, they

have rapidly evolved, which means that hundreds of

appearances and disappearances can in principle be

used either to subdivide or date rock strata. Finally

yet importantly, the tiny size (from ca. 1 to 30 lm)

is sometimes of great usefulness speciﬁcally when

the amount of the sample to study is limited.

Biohorizons

The biohorizon represents the basis of biostratigra-

phy and is deﬁned as a stratigraphical boundary or

surface recognized in a succession of sedimentary

rocks, where a change in the fossil content is

observed. According to this deﬁnition, a biohorizon

is any difference in the palaeontological content,

which differentiates two packages of strata.

First (lowest) occurrences, last (highest) occur-

rences, and the beginning and end of acme/paracme

intervals are the most commonly used biohorizons

(Fig. 3). An important observation is that the ﬁrst

enter (appearance) or the exit (disappearance) of a

taxon in/from the geological record is often pre-

ceded or followed by sporadic occurrences prior or

after their common and continuous presence (core

distribution). This is why the ﬁrst or last continuous

and relatively common occurrence of a taxon may

represent a better biohorizon than the absolute ﬁrst

or last occurrence (Backman et al. 2012; Agnini

et al. 2014). This is especially true for calcareous

nannofossils for which quantitative abundance pat-

terns have been often produced and allow for very

detailed discussions on species stratigraphical distri-

butions/ranges and biohorizon placements. Tradi-

tionally, micro-palaeontologists have used First

Occurrence (FO) and Last Occurrence (LO) to

080604020 100 120

Species-richness/Rs/Re

Triassic

Carnian

Norian

Rhaetian

Hettangian

Sinemurian

Pliensbachian

Toarcian

Aalenian

Bajocian

Bathonian

Callovian

Oxfordian

Kimmeridgian

Tithonian

Jurassic

Berrasian

Valanginian

Hauterivian

Barremian

Aptian

Albian

Cenomanian

Turonian

Coniacian

Santonian

Campanian

Maastrichtian

Cretaceous

Danian

Paleogene Neogene

220

200

180

160

140

120

100

TOTAL NANNOFOSSIL

SPECIES RICHNESS

K-Pg

PETM

OAE2

OAE1d

OAE1c

OAE1b

OAE1a

J/C boundary

Toarcian OAE

T/J boundary

EXTINCTION RATE (Re)

SPECIATION RATE (Rs)

EOB

Mg/Ca mole ratio

6543210

Calcite IIAragonite II Aragonite III

60 40 20 0

Ca (meq/liter)

major sediment producers

Stanley & Hardie (1998)

Bown et al. (2004)

Diatom diversity

0100200

Spencer-Cervato (1999) 220

200

180

160

140

120

100

Origin and/

or Silificication

0 2000 4000

Atmospheric CO2 ppm

Royer et al. 2004

Pagani et al., 2005

T°C vs today

Royer et al. 2004

Zachos et al. 2001

010

Selandian

Thanetian

Ypresian

Bartonian

Lutetian

Priabonian

Rupelian

Chattian

Paleoc. Eocene Olig. Miocene

Aquitanian

Burdigalian

Langhian

Serravallian

Tortonian

Messinian

Zanclean

Piacenzian

Pli.

Quaternary

Period

Epoch

Age

ABCDE

Fig. 2. Calcareous nannofossil evolutionary rates and diatom diversity plotted against selected physical environmental parameters. A,

species-richness, speciation rate and extinction rate of calcareous nannofossils through the last 220 Myr (Bown et al. 2004); B, aragonite

and Calcite seas and major sediment producers (Stanley & Hardie 1998); C, diatom diversity (Spencer-Cervato 1999); D, atmospheric

(Royer et al. 2004; Pagani et al. 2005); E, temperature versus today value (Zachos et al. 2001; Royer et al. 2004). [Colour ﬁgure can

be viewed at wileyonlinelibrary.com]

LETHAIA 50 (2017) Cenozoic nannofossils in chronostratigraphy 449

describe the appearance and disappearance of a

taxon. More recently, other authors have suggested

that the use of the terms ‘ﬁrst’ and ‘last’ is incorrect

being related to the concept of time, while bios-

tratigraphy does not deal directly with time and bet-

ter explains the stratigraphical relative relationships

existing among rock strata (e.g. Aubry 2014). For

this reason, it has been proposed to use Lowest

Occurrence (LO) to indicate the lowest documented

occurrence of a taxon in a speciﬁc section and High-

est Occurrence to denote the highest documented

occurrence in a speciﬁc section (ICS 2017). The

presence of an acronym (LO) with two opposite

meanings have created ambiguity in the literature

because LO may refer to the Last Occurrence or the

Lowest Occurrence. To avoid any possible misun-

derstanding and according to recently published

Cenozoic calcareous nannofossil biozonations

(Backman et al. 2012; Agnini et al. 2014), we prefer

to use the concept of Base (B) and Top (T) to

describe the stratigraphical lowest and highest occur-

rences of taxa. Additional biohorizons such as the

Base common and continuous (Bc) and Top com-

mon and continuous (Tc) are proposed to be

employed in those cases in which sporadic occur-

rences were observed before the Base or after the

Top of a taxon (Fig. 3).

Counting methods and their reliability

In the last sixty years, calcareous nannofossil bios-

tratigraphical data have been collected by different

authors using different counting methodologies or

abundance estimations and this large amount of data

have enlightened the importance of the quality of

the biostratigraphical datums itself (Fig. 4).

Semi-quantitative and relative abundance counts

(Backman & Shackleton 1983; Rio et al. 1990) are

able to depict very precisely stratigraphical ranges

for any given species, and this, in turn, allows for a

correct recognition and positioning of a biohorizon,

this can improve the reproducibility of datums and

provide higher degree of correlatibility over wide,

regional to superregional areas. Range charts, which

are based on qualitative abundance estimations of

Older

stratigraphy

Younger AB ABAAB ABC

Biohorizon 1

(B, Bc, T, Tc)

Biohorizon 2

(B, Bc, T, Tc)

Species A

Taxon Range Zone

TRZ

Species A/B

Concurrent Range Zone

CRZ

Species A

Base Zone

Species A

Top Zone

Species C

Partial Range Zone

PRZ

Biohorizon 1

Bi, Ba

Biohorizon 2

Ti, Ta

Species A

Acme Zone

Species A

Paracme Zone

Range, Interval and abundance zones

B = Base

Bc = Base common

Bi = Base increase

Ba = Base absence

T = Top

Tc = Top common

Ti = Top increase

Ta = Top absence

Fig. 3. Range, Interval and Abundance Zones used in calcareous nannofossil biozonations. Redrawn and implemented after Wade et al.

(2011) and Backman et al. (2012).

n/mm2Range chartA/P

0520

(m)

Species A

Fig. 4. Idealized plots of Species A using the same initial data set.

A, semi-quantitative abundance pattern (number of specimens/

). B, range chart: D =dominant (>100 specimens per ﬁeld

of view –FOV); A =abundant (>10–100 specimens per FOV);

C=common (>1–10 specimens per FOV); F =few (1 specimen

per 1–10 FOV); R =rare (<1 specimen per 10 FOV). C, abun-

dance/presence (A/P) plot.

450 Agnini et al. LETHAIA 50 (2017)

taxa, represent a precious data set but the main pit-

fall is that they do not result in abundance distribu-

tion patterns but rather in oversimpliﬁed

stratigraphical ranges. Finally, absence/presence

data, which are still commonly used in applied ﬁelds,

as for instance in oil companies, are a poor way to

gain insight on abundance patterns despite their use-

fulness for getting quick biostratigraphy.

Last but not least, we would underline one more

time the importance of acquiring high-resolution

data. Regrettably, low-resolution data could be

affected by profound distortions of the real data due

to the serious loss of information. An example of the

aliasing effect is reported in Figure 5, where low-

resolution and high-resolution abundance patterns

of an idealized species A are compared. The positions

of the Base and Top of species A show remarkable

differences that would eventually result in inconsis-

tent biostratigraphical data. This is why collecting

and analysing samples should guarantee the capture

of all the necessary details. A good strategy should

thus consider and try to ﬁnd an acceptable compro-

mise between the amount of time spent analysing

the sample and the quality of the ﬁnal biostrati-

graphical data.

The take-home message is that biostratigraphy is a

quite complicate discipline and having a quantitative

highly resolved data set is an essential requisite to

collect good-quality data and discuss on the reliabil-

ity and reproducibility of a biohorizon. For this rea-

son, a shared standardization in terms of counting

methods and resolution is auspicable.

Taxonomy

Besides the use of poor-quality data, possible incon-

sistency of biostratigraphical results is linked to

ambiguous taxonomy. Biostratigraphy is strictly

related to systematic as clear, unambiguous and

shared taxonomic concepts for marker species are

undoubtedly needed to obtain reliable biostrati-

graphical data.

As for taxonomy, calcareous nannofossils are per

se quite a complicated group of microfossils because

the planktonic algae producing them are character-

ized by heteromorphic life cycles, during which the

organism secretes different coccoliths or organic

scales or naked cells (e.g. Billard & Inouye 2004).

Every single species could in fact produce different

covers each of which is described as a different inde-

pendent species when observed in the sediments/

assemblages. It also happens that morphologically

similar calcite plates do not belong to the same spe-

cies but rather represents a cryptospecies (De Vargas

et al. 2004). These evidences have been available

from studies on living coccolithophores but likely

00050 n/mm2

Species A

n/mm2

Low resolutionHigh resolution

(m)

Bhighres

Blowres

Bchighres

Tlowres

Thighres

500

Fig. 5. High-resolution A, and low-resolution B, abundance patterns of Species A. The aliasing effect is particularly evident in the low-

resolution data set where the signal is completely distorted by the loss of information. The sampling resolution is of 10 cm in A and of

100 cm in B. Biohorizons are positioned at the mid-points.

LETHAIA 50 (2017) Cenozoic nannofossils in chronostratigraphy 451

represent a commonality of fossil species. Parataxon-

omy rather than a natural classiﬁcation system could

thus describe nannofossils and be used to subdivide

this group.

Some taxonomic issues are instead related to the

formal description of a species, and this usually hap-

pens when the description of a new species is incom-

plete, missing fundamental morphological

characters, or ambiguous. Moreover, biostratigra-

phers are sometimes rough palaeontologists as they

disregard formal species descriptions or tend to use

their own taxonomic concept without mentioning it.

All these misconducts potentially result in an incor-

rect recognition of specimens and consequentially of

the species range. However, though the innumerable

complications, calcareous nannofossil taxonomy is

overall in an acceptable state, although attention and

caution should always be paid to avoid any possible

misinterpretation and/or confusion.

Biozones

The fundamental units in biostratigraphy are the

biozones. These are bodies of strata that are charac-

terized on the basis of their contained fossils. The

Base and Top of each biozone is deﬁned by biohori-

zons, which include any change in features related to

the content and distribution of fossils in strata (ICS

2017). This is a quite simple deﬁnition. Once you

have deﬁned the Base and Top biohorizons, you

have deﬁned the biozone. Any variation with respect

to the formal deﬁnition of a speciﬁc biozone, in a

biostratigraphical scheme, should be ofﬁcially

emended, otherwise you would obtain the undesir-

able effect of having a biozone represented by differ-

ent bodies of strata in the same section. In principle,

any change in the calcareous nannofossil content

could be used to subdivide rock strata. Anyway, the

most widely used biohorizons are ﬁrst occurrences,

last occurrences and changes in abundance of taxa.

A number of range, interval and abundance zones

can be deﬁned using Base (B, Bc, Bi and Ba) and

Top (T, Tc, Ti and Ta) of a particular taxon or a

combination of two taxa (Fig. 3).

Biozonations

Biohorizons and, hence, biozones are ordered in

stratigraphical order and eventually result in a bios-

tratigraphical zonation/scheme (biozonation). Since

Bramlette & Riedel (1954) published their pivotal

work on the potentiality of calcareous nannofossils

as biostratigraphical tools, decades passed before

comprehensive syntheses became available to the

community (e.g. Martini 1971; Sissingh 1977; Roth

1978; Okada & Bukry 1980). A prodigious effort has

been made in collecting an enormous data set based

on marine successions cropping out on land or

located on the bottom of the seaﬂoor. This large

amount of information provides a much-reﬁned

biostratigraphical framework, which has been used

to produce more reliable biozonations for the Ceno-

zoic and Mesozoic.

Biochronology

Biostratigraphy and biochronology are tightly con-

nected; the former focuses on relative age dating of

rock strata/sediments based on biohorizons, and the

latter provides age estimations of these biohorizons.

The numerical ages estimated for each biohorizon

depend on the reliability of the biohorizon per se but

also on the time-scale adopted to calibrate the bio-

event. An astronomically Tuned Neogene Time Scale

(ATNTS) has been presented by Lourens et al.

(2004), and minor changes further reﬁned the

ATNTS2012 (Hilgen et al. 2012). The Astronomical

time-scale has been extended to the Oligocene

(P€

alike et al. 2006) and reconstructed for the

Palaeocene–Early Eocene (Westerhold et al. 2007,

2008; Hilgen et al. 2010; Vandenberghe et al. 2012).

Recent studies have tried to close the Eocene gap so

as to eventually develop a continuous astronomically

calibrated geological time-scale for the entire Ceno-

zoic Era and potentially open the way for extending

the ATS into the Mesozoic (T. Westerhold, U. R€

ohl,

T. Frederichs, C. Agnini, I. Rafﬁ, J.C. Zachos & R.H.

Wilkens, in review). In the next years, the numerical

ages estimated for calcareous nannofossil biohori-

zons will be inevitably subject to change just as a

consequence of the instability of the early Palaeogene

time-scale.

Overview of Cenozoic calcareous

nannofossil biostratigraphy

Cenozoic calcareous nannofossils are considered the

most powerful biostratigraphical tool for correla-

tions over wide areas in the marine realm. The main

input to the development and reﬁnement of bio-

zonations based on calcareous nannofossil biohori-

zons has been and is coupled to the tremendous

amount of data retrieved and available from sedi-

ments recovered by Ocean Drilling Programs (i.e.

DSDP, ODP and IODP). However, sedimentary suc-

cessions cropping out on land are also crucial to cre-

ate a complete and comprehensive data set, which

includes data from different biogeographical

domains and depositional settings.

452 Agnini et al. LETHAIA 50 (2017)

A ﬁrst Cenozoic biozonation was published by

Martini (1971), and deﬁned as ‘standard’ by the

author. This biostratigraphical scheme used an

alphanumerical notation: NP (Nannoplankton

Palaeogene) for the Palaeogene with a total number

of 25 biozones and NN (Nannoplankton Neogene)

for the Neogene which consists of 21 biozones. In

the same years, D. Bukry was studying calcareous

nannofossil assemblages in kilometres of DSDP core

sediments which allowed him constructing an alter-

native Cenozoic zonation (Bukry 1973, 1975), with

biozones afterwards formally code-numbered as CP

(Coccolith Palaeogene), and CN (Coccolith Neo-

gene), zones by Okada & Bukry (1980). An impor-

tant synthesis of nannofossil biostratigraphy was

published in the 1980s by Perch-Nielsen (1985) and

precious contributions came also from Young

(1998) and Hine & Weaver (1998), who synthesized

the nannofossil biostratigraphy for the Neogene and

the Quaternary, respectively.

Regional biozonations have also been played an

important role in deﬁning similarities and differ-

ences between areas. For the Palaeogene, high lati-

tudes and Mediterranean biozonations have been

proposed (Catanzariti et al. 1997; Varol 1998; For-

naciari et al. 2010) and important improvements

have been achieved for Neogene calcareous bios-

tratigraphy for the Mediterranean region (Fornaciari

& Rio 1996; Fornaciari et al. 1996).

More recently, two new biozonations valid for the

low-middle latitudes have been published for the

Neogene–Quaternary and the Palaeogene (Backman

et al. 2012; Agnini et al. 2014). The main aim of

these works was to re-evaluate the biozonations of

Martini (1971) and Okada & Bukry (1980) through

the integration of those biohorizons that have

proved to be reliable and substituting problematic

(unreliable) biohorizons with new ones. The code

system used is CN (Calcareous Nannofossils) fol-

lowed by letters indicating the Epoch (P –Palaeo-

cene, E –Eocene, O –Oligocene; M –Miocene and

PL –Pliocene/Pleistocene; Figs 6, 7).

Cenozoic calcareous nannofossil biochronology

From the publication of the ﬁrst Cenozoic time-scale

(Funnell 1964), biostratigraphy has served as a

framework to check chronological data (e.g. magne-

tostratigraphy, cyclostratigraphy and radiometric

dating). Subsequently, the biostratigraphical data

have been calibrated to chronological data and pro-

vide numerical ages for the biohorizons.

Since then, Cenozoic calcareous nannofossil

biochronology has amazingly developed (Berggren

et al. 1985, 1995; Gradstein et al. 2012) and reviews

of astro-biochronological calibration of Neogene

and Quaternary nannofossil datum events have been

provided (Rafﬁ et al. 2006; Backman et al. 2012).

Going back through the Palaeogene, the time-scale is

to be considered as a work in progress and, even if

biostratigraphical biohorizons are sufﬁciently tested

and integrated with magneto- and astro-cyclostrati-

graphy, the numerical ages now available will be

subjected to changes anytime the time-scale

would change (see Agnini et al. 2014, for detailed

discussion).

The role of calcareous nannofossils in Cenozoic

chronostratigraphy

To completely understand the all-important role

that calcareous nannofossils play in the Cenozoic

chronostratigraphy, we will discuss the biohorizons

that possibly denote the nine Palaeogene, the eight

Neogene and the ﬁve Quaternary stages, used as cor-

relation biohorizon and/or complementary criterion

for recognition of chronostratigraphical GSSPs.

Every Cenozoic chronostratigraphical unit has been

or will be deﬁned by a speciﬁc boundary level in a

reference section, the Global Stratotype Standard-

section and Point (GSSP), based on different marker

events of optimal correlation potential. Except for

very few exceptions (e.g. base of Holocene), calcare-

ous nannofossils provide clear biohorizons that

denote or approximate the position of chronostrati-

graphical boundaries in the Cenozoic. Starting from

the base of the Palaeogene, we will give a complete

overview of these biohorizons. In this discussion,

ages of the chronostratigraphical units as well as ages

of the considered biohorizons are those reported in

the recently published Cenozoic calcareous nanno-

fossil biozonations or in the Geological Time Scale

2012 (Backman et al. 2012; GTS12; Agnini et al.

2014). We are aware that this may cause some

inconsistencies with some data published in litera-

ture, especially for the Palaeogene interval. However,

the Palaeogene time-scale is in continuous change

and both the numbers reported in this work and the

GTS12 could not be valid anymore in the next

future. The idea here is just to give a comprehensive

summary of the calcareous nannofossil biohorizons

in relation to the position and deﬁnition of chronos-

tratigraphical units and, even more importantly,

their relative ranking and spacing.

The Palaeogene Stages

The GSSP of Danian Stage was ratiﬁed in 1991

(Molina et al. 2006) at the El Kef section (Tunisia);

this boundary coincides with the base of the

LETHAIA 50 (2017) Cenozoic nannofossils in chronostratigraphy 453

55.0

56.0

57.0

58.0

59.0

60.0

61.0

62.0

63.0

64.0

65.0

C25n

C26n

C27n

C28n

C29n

C24r

C25r

C26r

C27r

C28r

C29r

Paleocene

Danian Selandian Thanetian

35.0

36.0

37.0

38.0

39.0

40.0

41.0

42.0

43.0

44.0

45.0

46.0

47.0

52.0

48.0

49.0

50.0

51.0

53.0

54.0

C16n

C15n

C17n

C18n

C13r

C20n

C19n

C18r

C16r

C17r

C19r

C20r

C21r

C22r

C23r

C21n

C22n

C23n

C24n

Ypresian Lutetian PriabonianBartonian

Eocene

C7n

C7An

C8n

C9n

C10n

C6Cr

C10r

C67r

C8r

C11r

C12r

C7Ar

C9r

C11n

C12n

C13n

24.0

25.0

26.0

27.0

28.0

29.0

30.0

31.0

32.0

33.0

34.0

Oligocene

GPTS

Age (Ma)

23.0 Mioc.

C6Cn

ChattianRupelian

Epoch

Stage

CNP7

CNP6

CNP5

CNP4

CNP3

CNP2

CNP8

CNP9

CNP10

CNP11

B Discoaster multiradiatus (56.01)

B Discoaster backmanii (56.95)

B Discoaster mohleri (57.57)

B Heliolithus cantabriae (58.27)

B Fasciculithus ulii (60.31)

B Sphenolithus moriformis group (60.74)

B T oweius pertusus (circular) (62.03)

B Prinsius martinii (62.62)

Bc Praeprinsius dimorphosus (64.32)

Bc Coccolithus pelagicus (64.76)

T Cretaceous nannoflora = K/Pg

B. bigelowi PRZ

C. pelagicus BZ

P. dimorphosus

P. martinii BZ

T. pertusus BZ

S. moriformis gr. BZ

F. ulii BZ

D. mohleri BZ

H. cantabriae BZ

D. backmanii BZ

NP8

NP9

NP3

NP1

NP2

NP4

NP5

NP6

CP8a

CP6

CP7

CP3

CP2

CP1b

CP1a

CP4

CP5

NP7

CNP1

T Discoaster barbadiensis (34.77)

T Discoaster saipanensis (34.44)

B Dictyococcites bisectus (40.36)

Tc Cribrocentrum reticulatum (35.26)

B Tribrachiatus contortus (54.0)

T Tribrachiatus orthostylus (50.66)

Bc Discoaster sublodoensis ‘5-rayed’

(48.96)

B Nannotetrina alata gr. (46.80)

B Nannotetrina cristata (47.99)

T Discoaster lodoensis (48.37)

T Chiasmolithus gigas (43.96)

Bc Reticulofenestra umbilicus (43.06)

B Chiasmolithus gigas (46.11)

B Tribrachiatus orthostylus (53.67)

T Fasciculithus richardii gr. (55.0)

Bc Cribrocentrum reticulatum (42.37)

F. tympaniformis TZ

Bc Discoaster lodoensis (52.64)

BCribrocentrum isabellae (36.13)

I. recurvus PRZ

C. isabellae/

C. reticulatum CRZ

D. saipanensis TZ

CNE20

CNE19

T. eminens PRZ

T. orthostylus BZ

N. alata gr. BZ

D. lodoensis/

T. orthostylus

CRZ

CNE8

CNE1

CNE6

CNE5

CNE4

CNE3

CNE2

D. barbadiensis PRZ

C. gigas TRZ

D. bisectus /

S. obtusus

CRZ

C. grandis PRZ

C. erbae TRZ

CNE18

CNE17

CNE16

CNE15

CNE14

CNE9

CNE10

CNE11

CNE13 R. umbilicus BZ

B Discoaster diastypus (54.13)

Bc Cribrocentrum erbae (37.88)

T Sphenolithus obtusus (38.47)

Tc Cribrocentrum erbae (37.46)

NP20

NP19

CP16a

CP15a

CP14b

CP13a

CP10

CP11

CP12b

B Coccolithus crassus (50.93)

CP9b

NP10

NP11

NP12

NP13

NP14

NP15

NP18

NP17

NP16

NP21

CNE7

R. dictyoda

PRZ

CP8b

CP9a

CP12a

CP13b

CP13c

CP14a

CP15b

C. reticulatum

N. cristata BZ

D. sublodoensis /

D. lodoensis CRZ

S. cuniculus/C.gigas

CRZ

T Sphenolithus ciperoensis (24.36)

TSphenolithus distentus (26.81)

B Sphenolithus distentus (30.0)

T Ericsonia formosa (32.92)

B Sphenolithus ciperoensis (27.14)

B Sphenolithus delphix (23.38)

NP24

NP25

NP23

NP22

T Reticulofenestra umbilicus (32.02)

CP19b

CP18

CP16c

CP17

CNO6

CNO5

CNO2

CNO3

CNO4

CNO1

CN1a

Agnini et al. (2014)

E. formosa CRZ

R. umbilicus TZ

D. bisectus

PRZ

S. distentus/

S.predistentus

CRZ

S. ciperoensis

T. carinatus

PRZ

T Sphenolithus predistentus (26.93)

CP16b

CN1b

CP19a

Okada &

Bukry1980

Martini

1971

CALCAREOUS NANNOFOSSIL ZONES BIOHORIZONS

T Sphenolithus delphix (23.06)

NN1

D. multiradiatus/

F. richardii gr. CRZ

T Fasciculithus tympaniformis (54.71)

Bc Sphenolithus cuniculus (44.64)

Nannotetrina spp.

PRZ

CNE12

B Sphenolithus furcatolithoides “B” (40.51)

H. compacta TZ

CNE21 Bc Clausicoccus subdistichus (33.88)

Late

Aquit.

Maast. W. barnasiae

2 μm

M. murus

2 μm

5 μm

F. ulii F. tympaniformis

5 μm

H. kleinpellii

5 μm

H. mohleri

D. araneus

5 μm

R. calcitrapa

5 μm

F. richardii

5 μm

B. inflatus

5 μm 5 μm

N. cristata

5 μm

C. reticulatum

5 μm

D. bisectus

(>10 μm)

5 μm

S. furcatolithoides

morph. B

5 μm

C. erbae

5 μm

C. oamaruensis

5 μm

C. grandis

2 μm

C. sudistichus

5 μm

D. saipanensis

S. ciperoensis

2 μm

S. predistentus

2 μm

STAGE INDEX-SPECIES

S. delphix

2 μm

Fig. 6. Palaeogene calcareous nannofossil biozonations (modiﬁed from Agnini et al. 2014): CP (Okada & Bukry 1980), NP (Martini

1971), CN (Agnini et al. 2014). The Geomagnetic Polarity Time Scale (GPTS) is after P€

alike et al. (2006), from the top of Chron C13r

(33.705 Ma), to the base of Chron C19n (41.510 Ma) in the Middle Eocene, and after Cande & Kent (1995; CK95), from the top of

Chron C20n (42.356 Ma) downward. Grey boxes and dashed lines show the uncertainty in deﬁning chronostratigraphic and biozone

boundaries. CN biochronology from Agnini et al. (2014). On the right, images of CN stage index-species are taken from literature (see

Appendix S1 for details). *=Base; +=Top; x =crossover. [Colour ﬁgure can be viewed at wileyonlinelibrary.com]

454 Agnini et al. LETHAIA 50 (2017)

Palaeogene system (Palaeocene series) and was

deﬁned at the base of a dark clay layer that docu-

ments the last among the big ﬁve mass extinctions.

Calcareous nannofossils suffered a profound extinc-

tion event followed by a relatively slow recovery. The

disappearance of Cretaceous nannoﬂora (e.g. the

genera Watznaueria and Micula) characterizes the

base of the Cenozoic and could serve to denote the

base of the Danian Stage (Fig. 6).

The GSSP of Selandian Stage, the second stage in

the Palaeocene series, was ratiﬁed in 2008 (Schmitz

et al. 2011) at the Zumaia Section, in coincidence of

the base of the Itzurun Formation. Two calcareous

nannofossil biohorizons are in fact useful to approx-

imate the base of the Selandian, the Base of Fasci-

culithus/Lithoptychius ulii (Aubry et al. 2011), which

also coincides with the so-called second radiation of

fasciculiths (sensu Steurbaut & Sztr

akos 2008; Mone-

chi et al. 2013), and the Base of Fasciculithus tympa-

niformis (Fig. 6).The ﬁrst biohorizon predates the

boundary by 21 kyr while the second postdates the

base of the Selandian by ca. 80–100 kyr (Bernaola

et al. 2009).

Similarly to the Selandian GSSP, also the GSSP of

the Thanetian Stage was ratiﬁed at the Zumaia Sec-

tion (Schmitz et al. 2011). This boundary is posi-

tioned at the base of a clay interval within the

Itzurun Formation and coincides with the base of

Chron C26n (Dinar

es-Turell et al. 2007). The evolu-

tion of the genus Heliolithus and speciﬁcally, the

appearance (Base) of Heliolithus kleinpelli was

reported to consistently occur in the uppermost part

of Chron C26r (Backman 1986; Bralower et al. 2002;

Agnini et al. 2007, 2014), in correspondence with

12.0

13.0

14.0

15.0

16.0

17.0

18.0

19.0

20.0

21.0

22.0

23.0

C5Br

C5Cn

C1r

C2An

C3n

C3r

C3Br

C3An

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

T. carinatus PRZ

CALCAREOUS NANNOFOSSIL ZONES BIOHORIZONSGPTS

Age (Ma)

0.0

T Pseudoemiliania lacunosa (0.43)

Epoch

Stage

24.0

C5n

C5r

CAn

CAr

C3Ar

C4n

C4r

C4Ar

C4An

C6An

C6Cn

C6Cr

C6Bn

C6Br

C6AAr

C6Ar

C5Er

C5Dn

C6n

C6r

C5Dr

C5En

C5Cr

C5AD

C1n

C2r

C2n

C2Ar

B Emiliania huxleyi (0.29)

Ta Gephyrocapsa (≥ 4 μm)(1.06)

CNPL6

CNPL5

CNPL7

CNPL8

CNPL9

CNPL10

CNPL11

CNPL4

T Discoaster brouweri (1.93)

T Discoaster pentaradiatus (2.39)

T Discoaster tamalis (2.76)

T Reticulofenestra pseudoumbilicus (3.82)

T Gephyrocapsa (>5.5 μm) (1.25)

B Gephyrocapsa (≥ 4 μm) (1.71)

T Ceratolithus acutus (5.04)

B Ceratolithus acutus (5.36)

T Discoaster quinqueramus (5.53)

Bc Discoaster asymmetricus (4.04)

CNM20

CNPL1

CNPL3

CNPL2

D.quinqueramus TZ

CNM17

CNM14

CNM3

CNM2

CNM4

CNM5

CNM6

CNM7

CNM8

CNM1

CNO6

CNM13

CNM11

CNM9

CNM16

CNM18

CNM19

CNM12

CNM10

CNM15

T Nicklithus amplificus (5.98)

B Nicklithus amplificus (6.82)

B Amaurolithus spp. (7.39)

T Discoaster hamatus (9.65)

B Discoaster hamatus (10.49)

B Catinaster coalitus (10.79)

Bc Discoaster kugleri (11.88)

Tc Discoaster kugleri (11.60)

T Sphenolithus heteromorphus (13.53)

Bc Sphenolithus heteromorphus (17.75)

B Sphenolithus belemnos (19.01)

Tc Calcidiscus premacintyrei (12.57)

B Discoaster signus (15.73)

B Sphenolithus disbelemnos (22.41)

T Sphenolithus delphix (23.06)

X Helicosphaera euphratis/H. carteri (20.89)

Tc Triquetrorhabdulus carinatus (22.10)

B Discoaster berggrenii (8.20)

Ba Reticulofenestra pseudoumbilicus (8.80)

D. hamatus TRZ

Amaurolithus spp. BZ

D. signus/

S. heteromorphus

CRZ

S. conicus PRZ

S. disbelemnos/T. carinatus CRZ

C. acutus TRZ

T. rugosus PRZ

N.amplificus TRZ

D. berggrenii BZ

D. bellus BZ

R. pseudoumbilicus PRZ

C. coalitus BZ

S. heteromorphus BZ

D.variabilis PRZ

D. exilis PRZ

D. kugleri TRZ

S. belemnos BZ

H. carteri PRZ

H. euphratis PRZ

C. premacintyrei TZ

D. pentaradiatus TZ

D.asymmetricus/R.pseudoumbilcus CRZ

D. tamalis TZ

Gephyrocapsa (≥ 4 μm)BZ

S. neoabies PRZ

Small Gephyrocapsae PRZ

Gephyrocapsa (≥ 4 μm)

/P. lacunosa CRZ

C. cristatus PRZ

D. brouweri TZ

C. macintyrei PRZ

Backman et al. (2012)

NN9

NN6

CN5b

NN1

CN1b

CN1c

CN5a

NP25

Okada and

Bukry (1980)

Martini

(1971)

NN19

CN13a

CN13b

CN14a

NN18

NN17

CN12b

CN12c

CN12d

NN16

CN12a

CN15 NN21

NN20CN14b

NN2

NN3

CN2

CN4

CN3

CN9a

CN8b

CN8a

CN9b

CN6 NN8

NN4

NN5

NN10

NN11a

NN11b

NN7

CN1a

CN7

CN10a

NN13

NN12

NN14/NN15

CN10b

CN10c

CN11a

CN11b

Olig. Miocene Pliocene Pleist.

Chattian

Aquitanian

Burdigalian

Langhian

Serravallian

Tortonian

Messinian

Zanclean

Piacenzian

Gelasian

Calabrian

middle

upper

Holoc.

STAGE INDEX-SPECIES

B Helicosphaera ampliaperta (20.49)

T Discoaster surculus (2.53)

Tc Reticulofenestra asanoi (0.91)

C5Bn

C5AA

C5AB

C5AC

S. delphix

H. ampliaperta

5 μm

H. euphratis H. carteri

5 μm

D. signus

5 μm

S. heteromorphus

5 μm

D. kugleri

5 μm

A. primus A. delicatus

5 μm 5 μm

5 μm

C. acutus T. rugosus

5 μm

S. abies D. pentaradiatus D. surculus

5 μm 5 μm

D. brouweri

5 μm

Gephyrocaspa ≥4 μm E. huxleyi

2 μm 2 μm

S. heteromorphus

5 μm

H. ampliaperta

5 μm

D. quiqueramus

5 μm

D. tamalis

5 μm

++++

2 μm

R. asanoi

Fig. 7. Neogene calcareous nannofossil biozonation (modiﬁed from Backman et al. 2012): CP (Okada & Bukry 1980), NP (Martini

1971), CN (Backman et al. 2012). The Geomagnetic Polarity Time Scale (GPTS) is from Lourens et al. (2004). Grey box and dashed lines

show the uncertainty in deﬁning biozone boundaries. Biochronology is after Backman et al. (2012). On the right, images of CN stage

index-species are taken from literature (see Appendix S1 for details). *=Base; +=Top; x =crossover; °= acme end. [Colour ﬁgure

can be viewed at wileyonlinelibrary.com]

LETHAIA 50 (2017) Cenozoic nannofossils in chronostratigraphy 455

the Early Late Palaeocene Event (ELPE; Westerhold

et al. 2008) and thus potentially represents a good

approximation of the base of the Thanetian (Fig. 6).

However, at Zumaia, this biohorizon is positioned

in a signiﬁcantly lower stratigraphical position with

respect to all the other data available from literature.

One possible explanation for this inconsistency

could be linked to taxonomic uncertainty in

H. kleinpellii recognition, because of the presence of

intermediate forms between Heliolithus cantabriae

and H. kleinpelli. Hence, although this biohorizon is

considered reliable thus suggesting its use to approx-

imate the Thanetian GSSP, the alternative biohori-

zon proposed is the Base of Discoaster mohleri

(Fig. 6). This biohorizon is found to occur at the

very base of Chron C25r, that is ca. 350–400 kyr

after the boundary.

The GSSP of the Ypresian Stage was ratiﬁed in

2003 (Aubry et al. 2007) and is located at the base of

‘Bed 1 of of the Esna Formation’ at the Dababyia

Quarry section, in coincidence with the onset of the

negative carbon isotope excursion (CIE) marking

the base of the Palaeocene–Eocene Thermal Maxi-

mum (PETM). Recently, Khozyem et al. (2014) have

evidenced potentially serious limiting factors of this

GSSP and above all the presence of an erosion sur-

face at the base of the Palaeocene–Eocene boundary.

Nonetheless, the CIE remains the primary criterion

to denote the base of the Ypresian. Related to this

extreme warming episode and the perturbation in

the carbon cycle are profound modiﬁcations in the

terrestrial and marine biota (e.g. Sluijs et al. 2007).

Among these changes, several events are observed in

the calcareous nannofossil assemblages such as the

lowest occurrence (Base) of Rhomboaster spp. and

Discoaster araneus, and the extinction (Top) of the

large Fasciculithus richardii group (Fig. 6). These

biohorizons all occur in coincidence, or after few

kyrs, from this boundary thus allowing for a precise

recognition of the base of the Eocene series.

The GSSP of the Lutetian Stage was ratiﬁed in

2011 (Molina et al. 2011) and placed in a dark marly

level (positioned at 167.85 m) in the Gorrondatxe

section (Spain) in coincidence with the Base of the

calcareous nannofossil Blackites inﬂatus (Fig. 6), ca.

800 kyr above the base of Chron C21r. The ﬁnal

decision on the proposal of using the appearance of

B. inﬂatus to identify the base of the Lutetian was

eventually taken because this biohorizon is the clos-

est to the position of Lutetian historical stratotype

(Molina et al. 2011). However, this taxon is some-

times absent in frankly open ocean sections (see

T. Westerhold, U. Ro

¨hl, T. Frederichs, C. Agnini,

I. Rafﬁ, J.C. Zachos & R.H. Wilkens, in review).

Moreover, the comparison of multiple ODP-IODP

Sites drilled in the equatorial Atlantic (Site 1258;

T. Westerhold, U. R€

ohl, T. Frederichs, C. Agnini,

I. Rafﬁ, J.C. Zachos & R.H. Wilkens, in review),

SE Atlantic (1262–1267; T. Westerhold, U. R€

ohl,

T. Frederichs, C. Agnini, I. Rafﬁ, J.C. Zachos & R.H.

Wilkens, in review) and NW Atlantic (U1409–

U1410, Norris et al. 2014), and the Possagno section

(Italy; Agnini et al. 2006) have evidenced that Base

of B. inﬂatus consistently lies at Chron C21r/C21n

transition and it is always found to slightly predate

the Base of Nannotetrina cristata (=Base of

Nannotetrina spp.) (Agnini et al. 2014; Norris et al.

2014; T. Westerhold, U. R€

ohl, T. Frederichs,

C. Agnini, I. Rafﬁ, J.C. Zachos & R.H. Wilkens, in

review). Although the ranking and spacing observed

for these two biohorizons in the aforementioned

successions are perfectly in agreement with data

from the GSSP section, the position with respect to

magnetostratigraphy is instead signiﬁcantly differ-

ent, suggesting that some of the data available from

the Gorrondatxe section may need a thoughtful revi-

sion. Nevertheless, at least at present, this biohorizon

is used to deﬁne the Lutetian GSSP.

The GSSP of the Bartonian Stage has not been for-

mally deﬁned yet, but a magnetostratigraphical

study performed in the Barton Clay of Alum Bay

(England), where the Bartonian was ﬁrst described,

indicates that magnetochrons C18n, C18r and possi-

bly C19n have been recognized with the base of the

Bartonian lying within Chron C18r (ISPS 2017). In

2010, Jovane et al. proposed the base of Chron C18r

as primary criterion for deﬁning the base of the Bar-

tonian Stage. However, with the exception of mag-

netostratigraphy, other correlation tools such as

calcareous plankton biohorizons are not available in

this time interval. The Top of planktonic foraminifer

Gumbelitriodes nuttalli, which serves to deﬁne the

base of Zone E11 (Berggren & Pearson 2005) is

found, though with an uneven distribution, up to

Zone E14, a datum that evidences for the low relia-

bility of this bioevent. The Base of Cribrocentrum

reticulatum is now used to mark the base of Zone

CNE14 (Agnini et al. 2014) and, with respect to

magnetostratigraphy, is found to occur in the lower

mid-part of Chron C19r (Fig. 6), well before the

position reported in Jovane et al. (2007) that,

instead, is rather correlative with an increase in

abundance observed in the Tethyan realm (Forna-

ciari et al. 2010; Tori & Monechi 2013; Agnini et al.

2014). Although any discussion on reliability of cri-

teria for deﬁning the Bartonian GSSP is beyond the

scope of this work, on the basis of previous argu-

ments, we would like to suggest to take into consid-

eration the possibility to deﬁne it in correspondence

with the Middle Eocene Climatic Optimum (MECO,

456 Agnini et al. LETHAIA 50 (2017)

at ca. 40.5 Ma; Bohaty et al. 2009) during which sev-

eral biotic and geochemical markers are globally rec-

ognized. Speciﬁcally, among calcareous nannofossil

biohorizons, the Top of Sphenolithus furcatolithoides

morphotype B and the Base of Dictyococcites bisectus

(>10 lm in size =Reticulofenestra stavensis) could

be used to approximate the boundary (Agnini et al.

2014).

The GSSP of the Priabonian Stage has not been

deﬁned yet, but the leading candidate GSSP section

has been proposed in Northern Italy, at Alano di

Piave (Veneto). In the Alano section, the ‘Tiziano

Bed’, a crystal tuff layer, has been proposed to

deﬁne the boundary (Agnini et al. 2011). Close to

this stratigraphical level, nannofossil biohorizons

Base of Chiasmolithus oamaruensis, Top of Chias-

molithus grandis and Base common (Bc) of Cribro-

centrum erbae have been detected (Agnini et al.

2011). The ﬁrst two biohorizons have a low degree

of reliability, especially the appearance of C. oa-

maruensis, which however has been traditionally

used to recognize the base of the Priabonian (e.g.

Berggren et al. 1985, 1995). Thus, the Bc of C. er-

bae could be used as a primary criterion, although

the real strength of this proposal is related to the

occurrence of other good stratigraphical markers,

as the extinction of planktonic foraminifer Moro-

zovelloides crassatus (Wade et al. 2012), or the base

of Subchrons C17n.3n and C17n.2n (Agnini et al.

2011; GTS12), that are in fact observed close to the

proposed boundary (Fig. 6).

The GSSP of the Rupelian Stage was ratiﬁed in

1992 (Premoli Silva & Jenkins 1993) and deﬁned in

the Massignano section (Italy) at the base of a green-

ish grey marl bed in which both the planktonic fora-

minifera Hantkenina and Cribrohantkenina become

extinct, at an age estimation of 33.9 Ma. In terms of

calcareous nannofossil biostratigraphy, the boundary

lies within Zone NP21 and Subzone CP16a (Martini

1971; Okada & Bukry 1980), whose base are marked

by the Top of the Discoaster saipanensis and Dis-

coaster barbadiensis, respectively. These two biohori-

zons are known to occur tightly spaced, predating

the Eocene–Oligocene boundary by ca. 500–600 kyr.

Recently, the Bc of Clausicoccus subdistichus has been

proposed to deﬁne the base of Zone CN01 (Agnini

et al. 2014) with an age estimation of 33.9 Ma. This

biohorizon represents an increase in abundance of

the nominate taxon and could in fact be used to bet-

ter approximate the base of the Rupelian. Although

the precise recognition of Bc of C. subdistichus is

possible only if a quantitative counting approach is

adopted, nonetheless, this biohorizon could repre-

sent a promising criterion, to be further checked

(Fig. 6).

The GSSP of the Chattian has been ratiﬁed by

IUGS in 2016 and deﬁned in the Monte Cagnero

section, Central Italy (Coccioni et al. 2008, in press).

The Chattian GSSP is located at metre level 197 in

coincidence with the highest common occurrence

(HCO or Tc) of planktonic foraminifer Chiloguem-

belina cubensis (=base of Zone 05; Berggren & Pear-

son 2005), in the lower part of Chron C9n. This

biohorizon has been chosen as the primary marker

for deﬁning this chronostratigraphical unit. In terms

of calcareous nannofossil biostratigraphy, the Top of

Sphenolithus predistentus, which marks the base of

Zone CNO5 (Agnini et al. 2014), lies just below the

HCO of C. cubensis and thus predates the base of

the Chattian by less than 100 kyr if the astrocy-

clostratigraphical model of Coccioni et al. (in press)

is adopted.

The Neogene Stages

The GSSP of the Aquitanian Stage was ratiﬁed in

1996 in Lemme-Carrioso Section (Italy) (Steininger

et al. 1997), at 35 m from the top of the section that

coincides with the base of Subchron C6cn.2n

(23.03 Ma; GTS12). The authors suggested that, in

terms of calcareous nannofossils, the best approxi-

mation of the Aquitanian can be achieved using the

Top of Sphenolithus ciperoensis, which marks both

the base of Zone NN1 (Martini 1971) and Subzone

CN1a (Okada & Bukry 1980). More recently, Shack-

leton et al. (2000) based on data from ODP Sites

926 and 929, and DSDP Site 522 (Rafﬁ 1999; Shack-

leton et al. 1999), stated that the biostratigraphical

marker more relevant for correlating the Oligocene–

Miocene boundary is the short-range nannofossil

Sphenolithus delphix. Since then, the Top of S. del-

phix has been successfully used to approximate the

base of the Aquitanian Stage in carbonate-rich mar-

ine sediments (Fig. 7).

The GSSPs of the Burdigalian and the Langhian

stages have not been deﬁned yet. The deﬁnition of

Burdigalian GSSP is a recurrent problem. The

option to have the Burdigalian GSSP deﬁned in an

astronomically tuned deep marine section seems to

make this problem very difﬁcult to be solved. Till

now, no good candidate sections are available, and

the option to formally designate this boundary in an

ODP core will be seriously considered and discussed

within the Working group designated by the Sub-

commission on Neogene Stratigraphy (SNS), and

within the SNS itself. The calcareous nannofossil

biohorizons usually considered for approximating

the base of Burdigalian are Base of Helicosphaera

ampliaperta (20.43 Ma; Backman et al. 2012) or,

secondarily, the crossover in abundance between

LETHAIA 50 (2017) Cenozoic nannofossils in chronostratigraphy 457

Helicosphaera euphratis and Helicosphaera carteri

(20.89 Ma; Backman et al. 2012; Fig. 7).

As regards the Langhian Stage, the Working

Group of the SNS have identiﬁed three potential

GSSP candidates: the Mediterranean La Vedova

(Italy) and St. Peter’s Pool (Malta) sections and the

Atlantic Site DSDP 608. The primary proposed cor-

relation criteria are the Base of planktonic foramini-

fer Praeorbulina glomerosa curva, which falls at the

base of Chron C5Bn.2n (15.16 Ma; GTS12; Iac-

carino et al. 2011), and the top of magnetic polarity

chronozone C5Cn.1n (15.97 Ma; GTS12; ICS 2017).

Moreover, previous results from the Langhian his-

torical Stratotype section (Fornaciari et al. 1997)

suggested that the Preorbulina datum (i.e. Praeorbu-

lina sicana auctorum), the top Chron C5Cn.1n and

the Tc of H. ampliaperta are closely spaced and

could thus serve to approximate the base of the Lan-

ghian Stage. However, a detailed review of the Glo-

bigerinoides-Praeorbulina evolutionary lineage has

evidenced that the Praeorbulina datum (= Base of

Praeorbulina spp.) should be moved upward where

the ﬁrst species belonging to genus Praeorbulina

(namely P. glomerosa curva sensu Turco et al. 2011)

appears. Based on this reasoning, the critical interval

where the Langhian Stage should be deﬁned spans

from the Top Chron C5Cn.1n and the base of Chron

C5Bn.2n (=Base of P. glomerosa curva). Depending

on the ﬁnal decision for the position of this chronos-

tratigraphical unit, the nannofossil biohorizons Base

of Discoaster signus (15.73 Ma; Backman et al. 2012)

or Top common of H. ampliaperta (Di Stefano et al.

2011; 14;.86 Ma in Backman et al. 2012) could be

used to approximate the Langhian GSSP (Fig. 7).

The GSSP of the Serravallian Stage was ratiﬁed in

2007 in the Ras il Pellegrin section (Malta) (Hilgen

et al. 2009) at the base of the Blue Clay Formation,

in correspondence with the oxygen isotope event

Mi-3b. These authors emphasized the importance of

combining geochemical and bio-magnetostratigra-

phical data to recognize the exact position of the

boundary in open ocean settings. In terms of cal-

careous nannofossil biostratigraphy, the base of the

Serravallian Stage is approximated by the Top of

Sphenolithus heteromorphus and, secondarily, by the

Tc of Cyclicargolithus ﬂoridanus (Fig. 7). However, it

is worth noting that the Top of S. heteromorphus

shows a slight diachronity if Atlantic Ceara Rise and

Mediterranean data are compared with younger ages

estimated for open ocean settings (13.523 Ma; Back-

man & Rafﬁ 1997; Backman et al. 2012) with respect

to the Mediterranean area (13.654 Ma; Abels et al.

2005).

The GSSP of the Tortonian Stage was ratiﬁed in

2003 in the Monte dei Corvi Beach section (Italy)

(Hilgen et al. 2005) at the mid-point of the sapropel

of small-scale sedimentary cycle 76 (11.63 Ma;

GTS12), close to the Top of common calcareous

nannofossil Discoaster kugleri, the Top of planktonic

foraminifer Globigerinoides subquadratus and the

base of short normal Subchron C5r.2n (at 11.67 Ma;

GST2012). The Tortonian GSSP coincides with oxy-

gen isotope event Mi-5 of Miller et al. (1991). This

GSSP is clearly deﬁned and we conﬁrm that the best

calcareous nannofossil biohorizon to approximate

the Serravallian/Tortonian boundary is the Tc of

Discoaster kugleri (11.60 Ma, Backman et al. 2012;

Fig. 7).

The GSSP of the Messinian Stage was ratiﬁed in

2000 in the Oued Akrech section (Morocco) (Hilgen

et al. 2000) at the base of the reddish layer number

15. According to the authors, this point is closely

coincident with the appearance of planktonic fora-

minifer Globorotalia miotumida group and the cal-

careous nannofossil Amaurolithus delicatus, and is

associated with Subchron C3Br.1r (7.25 Ma;

GTS12). More recently, Rafﬁ et al. (2006) have evi-

denced that the appearance of Amaurolithus spp. (=

Base of Amaurolithus primus; Rafﬁ et al. 1998) is a

more reliable datum than the Base of A. delicatus

that seems to be restricted in the Mediterranean

area. For this reason, the appearance of the horse-

shoe-shaped Amaurolithus/Nicklithus/Ceratolithus

evolutionary lineage (=Base of A. primus), which

marks the base of Zone CNM17 (7.39 Ma; Backman

et al. 2012), is the preferred calcareous nannofossil

biohorizon to approximate the Tortonian–Messi-

nian boundary.

The GSSP of the Zanclean Stage, and the Pliocene

Series, was ratiﬁed in 2000 in the Eraclea Minoa sec-

tion (Italy) (Van Couvering et al. 2000) at the base

of the Trubi Formation in correspondence with the

insolation cycle 510 (5.33 Ma; GTS 12) and predat-

ing by only 96 kyr the onset of the Thvera magnetic

event (C3n.4n). Three are the calcareous nannofossil

biohorizons that serve to denote the Messinian/Zan-

clean boundary: the closest to the boundary, and vir-

tually coincident to it, is the Base of Ceratolithus

acutus (5.36 Ma; Backman et al. 2012), followed just

above by the Top of Triquetrorhabdulus rugosus

(5.23 Ma; Backman et al. 2012), which shows a very

consistent calibration both in the Mediterranean (Di

Stefano et al. 1996; Castradori 1998) and equatorial

Atlantic areas (Backman & Rafﬁ 1997). Below the

boundary, the Top of Discoaster quinqueramus that

occurs in open ocean sections at 5.53 Ma (Backman

et al. 2012) serves to approximate the Messinian/

Zanclean boundary but is useless in the Mediter-

ranean area because of the Salinity Crisis (Fig. 7)

interval. The presence of three highly reliable

458 Agnini et al. LETHAIA 50 (2017)

biohorizons restricted in ca. 300 kyr guarantees for a

very precise recognition of the Zanclean GSSP using

calcareous nannofossil biostratigraphy.

The GSSP of the Piacenzian Stage was ratiﬁed in

1997 in the Punta Piccola section (Sicily, Italy) (Cas-

tradori et al. 1998) at the base of the beige marl bed

of small-scale carbonate cycle 77, in correspondence

with the precessional cycle 347 (from the present) at

3.6 Ma (GTS12). The Gilbert/Gauss (C2Ar/

C2An.3n) magnetic reversal is documented immedi-

ately above the GSSP (at 3.596 Ma; GTS12) and is

considered the primary tool to denote the base of

the Piacenzian. However, the highest occurrence of

nannofossil Sphenolithus spp. (=Top Sphenolithus

abies, at 3.61 Ma; Backman et al. 2012) is considered

a reliable tool for wide correlations, which allows for

a precise positioning of the Piacenzian Stage out of

the GSSP section.

The Quaternary Stages

The GSSP of the Gelasian Stage was ratiﬁed in 1996 as

base of Upper Pliocene stage, and in 2009 as base of

Pleistocene and Quaternary (Rio et al. 1998; Gibbard

& Head 2010). The base of the Gelasian is deﬁned in

the Monte San Nicola section (Italy) at 62 m, in coin-

cidence with the base of the marly layer overlying

sapropel MPRS 250 and correlative with the isotopic

stage 103 (2.588 Ma; GTS12). The primary marker to

denote this chronostratigraphical unit is the Gauss/

Matuyama magnetic reversal (C2An.1n/C2r.2r),

which is located only 1 m below the GSSP. Close to

the GSSP, calcareous nannofossil biostratigraphy

provides some clear biohorizons occurring in close

sequential order that are Top of Discoaster tamalis

(2.76 Ma; Backman et al. 2012), Top of Discoaster

surculus (2.53 Ma; Backman et al. 2012) and Top of

Discoaster pentaradiatus (2.39 Ma; Backman et al.

2012), useful to approximate the Piacenzian/Gelasian

Boundary (Fig. 7). In particular, the Tops of D. ta-

malis and D. pentaradiatus, which mark the base and

top of Zone CNPL5 (Backman et al. 2012), precisely

bracket the base of the Gelasian Stage.

The GSSP of the Calabrian Stage was ﬁrstly rati-

ﬁed in 1985 in the Vrica section (Italy) (Aguirre &

Pasini 1985; Cita et al. 2012) at the base a claystone

overlying the sapropelic marker Bed ‘e’, correlative

with the Mediterranean Precession cycle 176 (at

1.806 Ma; GTS12). The top of the Olduvai magnetic

reversal (C2n) is located only ca. 15 kyr below the

boundary and is thus considered the best approxi-

mation for the base of the Calabrian. Aguirre &

Pasini (1985) reported the high correlation potential

of some of the palaeontological events observed

across the boundary (Lourens et al. 1996). Among

them, two calcareous nannofossil biohorizons

bracket the Calabrian GSSP, the Top of Discoaster

brouweri (=Top of Discoaster spp.), which predates

the base of the Calabrian (at 1.93 Ma; Backman

et al. 2012) and the base of medium size (4–5.5 lm)

Gephyrocapsa spp., which post-dates it (1.71 Ma;

Backman et al. 2012). The use of these paired bio-

horizons could further strengthen the recognition of

the Calabrian GSSP (Fig. 7).

The GSSP of the Middle Pleistocene Stage (i.e.

Ionian) has not been formally deﬁned, and three

candidate sections are presently under consideration

(Head & Gibbard 2015). Although a ﬁnal decision

has not been taken yet, the Brunhes/Matuyama

boundary (773 ka) has received the greatest support

as primary marker of the Ionian Stage (Head & Gib-

bard 2015). If this will be the ﬁnal decision, the main

calcareous nannofossil biohorizon that will possibly

denote this chronostratigraphical unit is the Top

absence of medium size Gephyrocapsa spp. (4–

5.5 lm), with an estimated age of 1.06 Ma (Back-

man et al. 2012) but the Tc of Reticulofenestra asanoi

could be possibly used as supplementary biohorizon

to approximate the Middle Pleistocene GSSP (Maio-

rano & Marino 2004; 0.91 Ma; Backman et al.

2012).

The GSSP of the Late Pleistocene Stage has not

been deﬁned yet but two proposals are under scru-

tiny: the Eemian (Amsterdam Terminal) proposal

(Pillans & Gibbard 2012) and the Tarentian (south-

ern Italy) proposal (Negri et al. 2015). Whatever will

be the ﬁnal decision, it is quite evident that this

Stage will correlate with the Marine Isotope Stage 5.

Unfortunately, calcareous nannofossils are not par-

ticularly useful in this time interval, even though the

Base of Emiliania huxleyi (at 0.29 Ma; Backman

et al. 2012) might very roughly approximate this

chronostratigraphical boundary.

The GSSP of the Holocene Stage was ratiﬁed in

2008 (Walker et al. 2009) in the NorthGRIP ice core

(Greenland). There are no calcareous nannofossil

biohorizons, which can approximate this boundary

satisfactorily.

Concluding remarks

We brieﬂy introduced the ﬁrst ﬁnding of calcareous

nannofossils and the successive intensive studies on

this group both on the biological and geological

point of view. We discussed some basic concepts of

biostratigraphy with special reference to calcareous

nannofossils, with some attention dedicated to the

different methodologies, that would allow to depict

the abundance pattern of any single taxon at best,

LETHAIA 50 (2017) Cenozoic nannofossils in chronostratigraphy 459

and emphasize the importance of highly resolved

data sets. A standardization of counting methodolo-

gies is highly recommendable in order to identify the

most useful and reproducible biohorizons, to con-

struct ﬁrm biostratigraphical frameworks and to

provide reliable biochronology. Finally, we also gave

a general review of the fundamental role played by

calcareous nannofossils in the Cenozoic chronos-

tratigraphy describing and discussing on the bio-

horizons that are used to characterize the Cenozoic

chronostratigraphical units.

Acknowledgements. – The 150th anniversary of the death of

Albert Oppel was celebrated during the STRATI 2015 –2nd

International Congress on Stratigraphy held in Graz with a ses-

sion dedicated on fossils in the modern chronostratigraphy man-

aged by Marco Balini (Milan University, Italy), Annalisa Ferretti

(Modena University, Italy), Stan Finney (Long Beach University,

USA) and Simonetta Monechi (Florence University, Italy). We

would thank all the conveners for their effort to convey at least

part of the contents in this special issue. We have appreciated all

the constructive comments and suggestions from both reviewers.

Primary support to CA, SM and IR came from MIUR grant

(PRIN2010-2011: 2010X3PP8J).

References

Abels, H.A., Hilgen, F.J., Krijgsman, W., Kruk, R.W., Rafﬁ, I.,

Turco, E. & Zachariasse, W.J. 2005: Long-period orbital con-

trol on middle Miocene global cooling: integrated stratigraphy

and astronomical tuning of the Blue Clay Formation on Malta.

Paleoceanography 20, PA4012.

Agnini, C., Muttoni, G., Kent, D.V. & Rio, D. 2006: Eocene bios-

tratigraphy and magnetic stratigraphy from Possagno, Italy:

the calcareous nannofossil response to climate variability.

Earth and Planetary Science Letters 241, 815–830.

Agnini, C., Fornaciari, E., Rafﬁ, I., Rio, D., R€

ohl, U. & Wester-

hold, T. 2007: High-resolution nannofossil biochronology of

middle Paleocene to early Eocene at ODP Site 1262: implica-

tions for calcareous nannoplankton evolution. Marine

Micropaleontology 64, 215–248.

Agnini, C., Fornaciari, E., Giusberti, L., Grandesso, P., Lanci, L.,

Luciani, V., Muttoni, G., P€

alike, H., Rio, D., Spofforth, D.J.A.

& Stefani, C. 2011: Integrated biomagnetostratigraphy of the

Alano section (NE Italy): a proposal for deﬁning the middle-

late Eocene boundary. Bulletin of the Geological Society of

America 123, 841–872.

Agnini, C., Fornaciari, E., Rafﬁ, I., Catanzariti, R., P€alike, H.,

Backman, J. & Rio, D. 2014: Biozonation and biochronology

of Paleogene calcareous nannofossils from low and middle lat-

itudes. Newsletters on Stratigraphy 47, 131–181.

Aguirre, E. & Pasini, G. 1985: The pliocene-pleistocene bound-

ary. Episodes 8, 115–120.

Aubry, M.-P. 2014: Biostratigraphy. In Rink, W.J. & Thompson,

J.W. (eds): Encyclopedia of Scientiﬁc Dating Methods,1–35.

Springer, Dordrecht, the Netherlands.

Aubry, M.-P., Ouda, K., Dupuis, C., Berggren, W.A., Van Cou-

vering, J.A., Ali, J., Brinkhuis, H., Gingerich, P.R., Heilmann-

Clausen, C., Hooker, J., Kent, D.V., King, C., Knox, R.W.O.B.,

Laga, P., Molina, E., Schmitz, B., Steurbaut, E. & Ward, D.R.

2007: The Global Standard Stratotype-section and Point

(GSSP) for the base of the Eocene Series in the Dababiya sec-

tion (Egypt). Episodes 30, 271–286.

Aubry, M.P., Bord, D. & Rodriguez, O. 2011: New taxa of the

Order Discoasterales Hay 1977. Micropaleontology 57,269–287.

Backman, J. 1986: Late Paleocene to middle Eocene calcareous

nannofossil biochronology from the Shatsky Rise, Walvis

Ridge and Italy. Palaeogeography, Palaeoclimatology, Palaeoe-

cology 57,43–59.

Backman, J. & Rafﬁ, I. 1997: Calibration of Miocene nannofossil

events to orbitally-tuned cyclostratigraphies from Ceara Rise.

Proceedings ODP, Scientiﬁc Results 154,83–99.

Backman, J. & Shackleton, N.J. 1983: Quantitative biochronology

of Pliocene and early Pleistocene calcareous nannoplankton

from the Atlantic, Indian and Paciﬁc Oceans. Marine Micropa-

leontology 8, 141–170.

Backman, J., Rafﬁ, I., Rio, D., Fornaciari, E. & P€

alike, H. 2012:

Biozonation and biochronology of Miocene through Pleis-

tocene calcareous nannofossils from low and middle latitudes.

Newsletters on Stratigraphy 45, 221–244.

Berggren, W.A. & Pearson, P.N. 2005: A revised tropical to sub-

tropical paleogene planktonic foraminiferal zonation. Journal

of Foraminiferal Research 35, 279–298.

Berggren, W.A., Kent, D.V., Flynn, J.J. & Van Couvering, J.A.

1985: Cenozoic geochronology. Geological Society of America

Bulletin 96, 1407–1418.

Berggren, W.A., Kent, D.V., Swisher, C.C. III & Aubry, M.-P.

1995: A revised Cenozoic geochronology and chronostratigra-

phy. In Berggren, W.A. et al. (eds): Geochronology, Time Scales

and Global Stratigraphic Correlation. Society for Sedimentary

Geology Special Publication 54, 129–212.Tulsa, OK.

Bernaola, G., Mart

ın-Rubio, M. & Baceta, J.I. 2009: New high

resolution calcareous nannofossil analysis across the Danian/

Selandian transition at the Zumaia section: comparison with

South Tethys and Danish sections. Geologica Acta 7,79–92.

Billard, C. & Inouye, I. 2004: What is new in coccolithophore

biology? In Thiersten, H.R. & Young, J.R. (eds): Coccol-

ithophores –From Molecular Processes to Global Impact,1–29.

Springer, Berlin.

Bohaty, S.M., Zachos, J.C., Florindo, F. & Delaney, M.L. 2009:

Coupled greenhouse warming and deep-sea acidiﬁcation in

the middle Eocene. Paleoceanography 24, PA2207.

Bown, P.R., Lees, J.A. & Young, J.R. 2004: Calcareous nanno-

plankton evolution and diversity through time. In Thiersten,

H.R. & Young, J.R. (eds): Coccolithophores –From Molecular

Processes to Global Impact, 481–508. Springer, Berlin.

Bralower, T.J., Premoli Silva, I. & Malone, M.J. (eds) 2002:

Extreme warmth in the Cretaceous and Paleogene: a depth

transect at Shatsky Rise, Central Paciﬁc. Proceedings of the

Ocean Drilling Program Scientiﬁc Results 198. http://www-odp.

tamu.edu/publications/198_IR/198ir.htm.

Bramlette, M.N. & Riedel, W.R. 1954: Stratigraphic value of dis-

coasters and some other microfossils related to recent coccol-

ithophores. Journal of Paleontology 28, 385–403.

Brownlee, C. & Taylor, A. 2004: Calciﬁcation in coccol-

ithophores: a cellular perspective. In Thiersten, H.R. & Young,

J.R. (eds): Coccolithophores –From Molecular Processes to Glo-

bal Impact,31–49. Springer, Berlin.

Bukry, D. 1973: Low-latitude coccolith biostratigraphic zonation.

Initial Reports of the Deep Sea Drilling Project 15, 685–703.

Bukry, D. 1975: Coccolith and silicoﬂagellate stratigraphy, north-

western Paciﬁc Ocean, Deep Sea Drilling Project Leg 32. Initial

Reports of the Deep Sea Drilling Project 32, 677–701.

Cande, S.C. & Kent, D.V. 1995: Revised calibration of the geo-

magnetic polarity time scale for the Late Cretaceous and Ceno-

zoic. Journal of Geophysical Research 100, 6093–6096.

Castradori, D. 1998: Calcareous nannofossils in the basal Zan-

clean of Eastern Mediterranean: remarkson paleoceanography

and sapropel formation. Proceedings of the Ocean Drilling Pro-

gram, Scientiﬁc Results 160, 113–123.

Castradori, D., Rio, D., Hilgen, F.J. & Lourens, L.J. 1998: The

Global Standard Stratotype-section and Point (GSSP) of the

Piacenzian Stage (Middle Pliocene). Episodes 21,88–93.

Catanzariti, R., Rio, D. & Martelli, L. 1997: Late Eocene to Oligo-

cene calcareous nannofossil biostratigraphy in the northern

Appennines: the Ranzano sandstone. Memorie di Scienze

Geolologiche 49, 207–253.

Cita, M.B., Gibbard, P.L., Head, M.J. et al. 2012: Formal ratiﬁca-

tion of the GSSP for the base of the Calabrian Stage (second

460 Agnini et al. LETHAIA 50 (2017)

stage of the Pleistocene Series, Quaternary System). Episodes

35, 338–397.

Coccioni, R., Marsili, A., Montanari, A. et al. 2008: Integrated

stratigraphy of the Oligocene pelagic sequence in the Umbria-

Marche basin (northeastern Apennines, Italy): a potential Glo-

bal Stratotype Section and Point (GSSP) for the Rupelian/

Chattian boundary. Bulletin of the Geological Society of America

120, 487–511.

Coccioni, R., Montanari, A., Bice, D., Brinkhuis, H., Deino, A.,

Frontalini, F., Lirer, F., Maiorano, P., Monechi, S., Pross, J.,

Rochette, P., Sagnotti, L., Sideri, M., Sprovieri, M., Tateo, F.,

Touchard, Y., Van Simaeys, S. & Williams, G.L. in press: Pro-

posal for establishing the GSSP for the base of the Chattian

Stage (Paleogene System, Oligocene Series) in the Monte Cag-

nero section, Italy. Episodes.

De Vargas, C., S

aez, A.G., Medlin, L.K. & Thierstein, H.R. 2004:

Super-species in the calcareous plankton. In Thiersten, H.R. &

Young, J.R. (eds): Coccolithophores –From Molecular Processes

to Global Impact, 271–298. Springer, Berlin.

De Vargas, C., Aubry, M.-P., Probert, I. & Young, J.R. 2007: Ori-

gin and evolution of coccolithophores: from coastal hunters to

oceanic farmers. In Falkowski, P.G. & Knoll, A.H. (eds): Evolu-

tion of Primary Producers in the Sea, 251–285. Academic Press,

Cambridge.

Di Stefano, E., Sprovieri, R. & Scarantino, S. 1996: Chronology

of biostratigraphic events at the base of the Pliocene. Palaeope-

lagos 6, 401–414.

Di Stefano, A., Verducci, M., Cascella, A. & Iaccarino, S.M. 2011:

Calcareous plankton events at the Early/Middle Miocene tran-

sition of DSDP Hole 608: comparison with Mediterranean

successions for deﬁnition of the Langhian GSSP. Stratigraphy

8, 145–161.

Dinar

es-Turell, J., Baceta, J.I., Bernaola, G., Orue-Etxebarria, X.

& Pujalte, V. 2007: Closing the Mid-Palaeocene gap: toward a

complete astronomically tuned Palaeocene Epoch and Selan-

dian and Thanetian GSSPs at Zumaia (Basque Basin, W. Pyre-

nees). Earth and Planetary Science Letters 262, 450–467.

Ehrenberg, C.G. 1836: Zus€

atze zur Erkenntniss grosser organis-

cher Ausbildung in den kleinsten thierischen Organismen.

Abhandlungen der K€

oniglichen Akademie der Wissenschaften zu

Berlin 1835, 150–181.

Falkowski, P.G., Katz, M.E., Knoll, A.K., Quigg, A., Raven, J.A.,

Schoﬁeld, O. & Taylor, F.J.R. 2004: The evolution of modern

eukaryotic phytoplankton. Science 305, 354–360.

Fornaciari, E. & Rio, D. 1996: Latest Oligocene to early middle

Miocene quantitative calcareous nannofossil biostratigraphy in

the Mediterranean region. Micropaleontology 42,1–36.

Fornaciari, E., Di Stefano, A., Rio, D. & Negri, A. 1996: Middle

Miocene quantitative calcareous nannofossil biostratigraphy in

the Mediterranean region. Micropaleontology 42,37–63.

Fornaciari, E., Iaccarino, S., Mazzei, R., Rio, D., Salvatorini, G.,

Bossio, A. & Monteforti, B. 1997: Calcareous plankton bios-

tratigraphy of the Langhian historical stratotype. In Monta-

nari, A., Odin, G.S. & Coccioni, R. (eds): Miocene Stratigraphy:

An Integrated Approach. Developments in Palaeontology and

Stratigraphy,volume 15,89–96, Elsevier, Amsterdam.

Fornaciari, E., Agnini, C., Catanzariti, R., Rio, D., Bolla, E.M. &

Valvasoni, E. 2010: Mid-Latitude calcareous nannofossil bios-

tratigraphy, biochronology and evolution across the middle to

late Eocene transition. Stratigraphy 7, 229–264.

Funnell, B.F. 1964: The tertiary period. The Quarterly Journal of

the Geological Society of London 120, 179–191.

Gibbard, P.L. & Head, M.J. 2010: The newly-ratiﬁed deﬁnition of

the Quaternary System/Period and redeﬁnition of the Pleis-

tocene Series/Epoch, and comparison of proposals advanced

prior to formal ratiﬁcation. Episodes 33, 152–158.

Gradstein, F.M., Ogg, J.G., Schmitz, M.D. & Ogg, G.M. (eds)

2012: The Geologic Time Scale 2012, 1144pp. Elsevier, Amster-

dam.

Hay, W.W. 2004: Carbonate ﬂuxes and calcareous nannoplank-

ton. In Thiersten, H.R. & Young, J.R. (eds): Coccolithophores –

From Molecular Processes to Global Impact, 509–528. Springer,

Berlin.

Head, M.J. & Gibbard, P.L. 2015: Formal subdivision of the Qua-

ternary System/Period: past, present, and future. Quaternary

International 383,4–35.

Hilgen, F.J., Iaccarino, S., Krijgsman, W., Villa, G., Langereis,

C.G. & Zachariasse, W.J. 2000: The Global Boundary Strato-

type Section and Point (GSSP) of the Messinian Stage (upper-

most Miocene). Episodes 23, 172–178.

Hilgen, F.J., Abdul Aziz, H., Bice, D., Iaccarino, S., Krijgsman,

W., Kuiper, K., Montanari, A., Rafﬁ, I., Turco, E. & Zachari-

asse, W.-J. 2005: The Global boundary Stratotype Section and

Point (GSSP) of the Tortonian Stage (Upper Miocene) at

Monte Dei Corvi. Episodes 28,6–17.

Hilgen, F.J., Abels, H.A., Iaccarino, S., Krijgsman, W., Rafﬁ, I.,

Sprovieri, R., Turco, E. & Zachariasse, W.J. 2009: The Global

Stratotype Section and Point (GSSP) of the Serravallian Stage

(Middle Miocene). Episodes 32, 152–166.

Hilgen, F.J., Kuiper, K.F. & Lourens, L.J. 2010: Evaluation of the

astronomical time scale for the Paleocene and earliest Eocene.

Earth and Planetary Science Letters 300, 139–151.

Hilgen, F.J., Lourens, L.J., Van Dam, J.A., Beu, A.G., Boyes, A.F.,

Cooper, R.A., Krijgsman, W., Ogg, J.G., Piller, W.E. & Wilson,

D.S. 2012: The neogene period. In Gradstein, F.M., Ogg, J.G.,

Schmitz, M.D. & Ogg, G.M. (eds): The Geologic Time Scale

2012, 923–978. Elsevier, Oxford.

Hine, N. & Weaver, P.P.E. 1998: Neogene. In Bown, P.R. (ed.):

Calcareous Nannofossil Biostratigraphy, British Micropalaeon-

tological Society Publication Series, 266–283. Chapman &

Hall, Berlin.

Huxley, T.H. 1858: On some organisms living at great

depths in the North Atlantic Ocean Quarterly. Journal of

Microscopical Science,8, New Series, 203–212. Scientiﬁc

Memoirs III Berlin.

Iaccarino, S.M., Di Stefano, A., Foresi, L.M., Turco, E., Bal-

dassini, N., Cascella, A., Da Prato, S., Ferraro, L., Gennari, R.,

Hilgen, F.J., Lirer, F., Maniscalco, R., Mazzei, R., Riforgiato,

F., Russo, B., Sagnotti, L., Salvatorini, G., Speranza, F. & Ver-

ducci, M. 2011: High-resolution integrated stratigraphy of the

upper Burdigalian-lower Langhian in the Mediterranean: the

Langhian historical stratotype and new candidate sections for

deﬁning its GSSP. Stratigraphy 8, 197–213.

ICS 2017: Stratigraphy.org (website of the International Subcom-

mission on Stratigraphy) 2017. http://www.stratigraphy.org/

upload/bak/bio.htm (accessed on 01/03/2017).

ISPS 2017: Paleogene.org/(website of the International Subcom-

mission on Paleogene Stratigraphy) 2017. http://www.paleoge

ne.org/working-group/bartonian/(accessed on 01/03/2017).

Jovane, L., Florindo, F., Coccioni, R., Dinar

es-Turell, J., Marsili,

A., Monechi, S., Roberts, A.P. & Sprovieri, M. 2007: The mid-

dle Eocene climatic optimum event in the Contessa Highway

section, Umbrian Apennines, Italy. Bulletin of the Geological

Society of America 119, 413–427.

Jovane, L., Sprovieri, M., Coccioni, R., Florindo, F., Marsili, A. &

Laskar, J. 2010: Astronomical calibration of the middle Eocene

Contessa Highway section (Gubbio, Italy). Earth and Planetary

Science Letters 298,77–88.

Kamptner, E. 1954: Untersuchungen €

uber den Feinbau der Coc-

colithen. Archiv f€

ur Protistenkunde 100,1–90.

Khozyem, H., Adatte, T., Keller, G., Tantawy, A.A. & Spangen-

berg, J.E. 2014: The Paleocene-Eocene GSSP at Dababiya,

Egypt –revisited. Episodes 37,78–86.

Lohmann, H. 1902: Die Coccolithophoridae. Archiv der Protis-

tenkunde. 1,89–165.

Lourens, L.J., Hilgen, F.J., Rafﬁ, I. & Vergnaud-Grazzini, C.

1996: Early Pleistocene chronology of the vrica section (Cal-

abria, Italy). Paleoceanography 11, 797–812.

Lourens, L.J., Hilgen, F.J., Shackleton, N.J., Laskar, J. & Wilson,

D. 2004: The neogene period. In Gradstein, F.M., Ogg, J.G. &

Smith, A.G. (eds), A Geological Timescale 2004, 409–440. Else-

vier, Amsterdam.

Maiorano, P. & Marino, M. 2004: Calcareous nannofossil bio-

events and environmental control on temporal and spatial pat-

terns at the early-middle Pleistocene. Marine

Micropaleontology 53, 405–422.

LETHAIA 50 (2017) Cenozoic nannofossils in chronostratigraphy 461

Martini, E. 1971: Standard Tertiary and Quaternary calcareous

nannoplankton zonation. In Farinacci, A. (ed.): Proceedings of

the Second Planktonic Conference Roma 1970,volume 2, 739–

785. Edizioni Tecnoscienza, Rome.

Miller, K.G., Wright, J.D. & Fairbanks, R.G. 1991: Unlocking the

ice house: Oligocene-Miocene oxygen isotopes, eustacy and

marginal erosion. Journal of Geophysical Results 96, 6829–6848.

Milliman, J.D. 1993: Production and accumulation of calcium

carbonate in the ocean: budget of a nonsteady state. Global

Biogeochemical Cycles 7, 927–957.

Molina, E., Alegret, L., Arenillas, I., Arz, J.A., Gallala, N., Har-

denbol, J., von Salis, K., Steurbaut, E., Vanderberge, N. &

Zaghbib-Turki, D. 2006: The global stratotype section and

point for the base of the Danian Stage (Paleogene, Paleocene,

‘Tertiary’, Cenozoic) at El Kef, Tunisia –original deﬁnition

and revision. Episodes 29, 263–273.

Molina, E., Alegret, L., Apellaniz, E., Bernaola, G., Caballero,

F., Dinares-Turell, J., Hardenbol, J., Heilmann-Clausen, C.,

Larrasoa~

na, J.C., Luterbacher, H., Monechi, S., Ortiz, S.,

Orue-Etxebarria, X., Payros, A., Pujalte, V., Rodr

ıguez-

Tovar, F.J., Tori, F., Tosquella, J. & Uchman, A. 2011:

The Global Stratotype Section and Point (GSSP) for the

base of the Lutetian Stage at the Gorrondatxe section,

Spain. Episodes 34,86–108.

Monechi, S., Reale, V., Bernaola, G. & Balestra, B. 2013: The

Danian/Selandian boundary at Site 1262 (South Atlantic) and

in the Tethyan region: biomagnetostratigraphy, evolutionary

trends in fasciculiths and environmental effects of the Latest

Danian Event. Marine Micropaleontology 98,28–40.

Murray, G. & Blackman, V.H. 1898: On the nature of cocco-

spheres and rhabdospheres. Philosophical Transactions of the

Royal Society B 190, 427–441.

Negri, A., Amorosi, A., Antonioli, F., Bertini, A., Florindo, F.,

Lurcock, P.C., Marabini, S., Mastronuzzi, G., Regattieri, E.,

Rossi, V., Scarponi, D., Taviani, M., Zanchetta, G. & Vai, G.B.

2015: A potential global boundary stratotype section and point

(GSSP) for the Tarentian Stage, Upper Pleistocene, from the

Taranto area (Italy): results and future perspectives. Quater-

nary International 383, 145–157.

Norris, R.D., Wilson, P.A., Blum, P. et al. 2014: Expedition 342

summary. Proceedings of the International Ocean Drilling Pro-

gram 342,1–149.

Okada, H. & Bukry, D. 1980: Supplementary modiﬁcation and

introduction of code numbers to the low-latitude coccolith

biostratigraphic zonation (Bukry, 1973; 1975). Marine

Micropaleontology 5, 321–325.

Pagani, M., Zachos, J.C., Freeman, K.H., Tipple, B. & Bohaty,

S.M. 2005: Marked decline in atmospheric carbon dioxide

concentrations during the Paleogene. Science 309, 600–603.

P€

alike, H., Norris, R.D., Herrle, J.O., Wilson, P.A., Coxall, H.K.,

Lear, C.H., Shackleton, N.J., Tripati, A.K. & Wade, B.S. 2006:

The heartbeat of the Oligocene climate system. Science 314,

1894–1898.

Perch-Nielsen, K. 1985: Cenozoic calcareous nannofossils. In Bolli,

H.M., Saunders, J.B. & Perch-Nielsen, K. (eds): Plankton

Stratigraphy,427–554. Cambridge University Press, Cambridge.

Pillans, B. & Gibbard, P. 2012: The quaternary period. In Grad-

stein, F.M., Ogg, J.G., Schmitz, M.D. & Ogg, G.M. (eds): The

Geologic Time Scale 2012,volume2, 979–1010. Elsevier, Oxford.

Premoli Silva, I. & Jenkins, D.J. 1993: Decision on the Eocene-

Oligocene boundary stratotype. Episode 16, 379–382.

Rafﬁ, I. 1999: Precision and accuracy of nannofossil biostrati-

graphic correlation. Philosophical Transactions of the Royal

Society A: Mathematical, Physical and Engineering Sciences 357,

1975–1993.

Rafﬁ, I., Backman, J. & Rio, D. 1998: Evolutionary trends of cal-

careous nannofossils in the Late Neogene. Marine Micropale-

ontology 35,17–41.

Rafﬁ, I., Backman, J., Fornaciari, E., P€

alike, H., Rio, D., Lourens,

L.J. & Hilgen, F.J. 2006: A review of calcareous nannofossil

astrobiochronology encompassing the past 25 million years.

Quaternary Science Review 25, 3113–3137.

Rio, D., Rafﬁ, I. & Villa, G. 1990: Pliocene-Pleistocene calcareous

nannofossil distribution patterns in the western Mediter-

ranean. Proceedings of the Ocean Drilling Program, Scientiﬁc

Results 107, 513–533.

Rio, D., Sprovieri, R., Castradori, D. & Di Stefano, E. 1998: The

Gelasian Stage (Upper Pliocene): a new unit of the global stan-

dard chronostratigraphic scale. Episodes 21,82–87.

Roth, P.H. 1978: Cretaceous nannoplankton biostratigraphy and

oceanography of the northwestern Atlantic Ocean. Initial

Reports of the Deep Sea Drilling Project 44, 731–759.

Royer, D.L., Berner, R.A., Monta~

nez, I.P., Tabor, N.J. & Beerling,

D.J. 2004: CO

as a primary driver of Phanerozoic climate.

GSA Today 14,4–10.

Schmitz, B., Pujalte, V., Molina, E. et al. 2011: The Global Strato-

type Sections and Points for the bases of the Selandian (Middle

Paleocene) and Thanetian (Upper Paleocene) stages at

Zumaia, Spain. Episodes 34, 220–243.

Shackleton, N.J., Crowhurst, S.J., Weedon, G.P. & Laskar, J.

1999: Astronomical calibration of Oligocene-Miocene time.

Philosophical Transactions of the Royal Society A: Mathematical,

Physical and Engineering Sciences 357, 1907–1929.

Shackleton, N.J., Hall, M.A., Rafﬁ, I., Tauxe, L. & Zachos, J.

2000: Astronomical calibration age for the Oligocene-Miocene

boundary. Geology 28, 447–450.

Sissingh, W. 1977: Biostratigraphy of Cretaceous calcareous

nannoplankton. Geologie en Mijnhouw 56,37–65.

Sluijs, A., Bowen, G.J., Brinkhuis, H., Lourens, L.J. & Thomas, E.

2007: The Palaeocene-Eocene Thermal Maximum super green-

house: biotic and geochemical signatures, age models and

mechanisms of global change. Geological Society Special Publi-

cation 323–349.

Sorby, H.C. 1861: On the organic origin of so-called ‘crystalloids’

of the chalk. The Annals and Magazine of Natural History Ser-

ies 3, 193–200.

Spencer-Cervato, C. 1999: The Cenozoic deep-sea microfossil

record: explorations of the DSDP/ODP sample set using the

Neptune database. Paleontologica Electronica 2,1–270.

http://palaeo-electronica.org/1999_2/neptune/issue2_99.htm.

Stanley, S.M. & Hardie, L.A. 1998: Secular oscillations in the car-

bonate mineralogy of reef-building and sediment-producing

organisms driven by tectonically forced shifts in seawater

chemistry. Palaeogeography, Palaeoclimatology, Palaeoecology

144,3–19.

Steininger, F.F., Aubry, M.-P., Berggren, W.A., Biolzi, M., Bor-

setti, A.M., Cartlidge, J.E., Cati, F., Corﬁeld, R., Gelati, R., Iac-

carino, S., Napoleone, C., Ottner, F., R€

ogl, F., Rretzel, R.,

Spezzaferri, S., Tateo, F., Villa, G. & Zevenboom, D. 1997: The

Global Stratotype Section and Point (GSSP) for the base of the

Neogene. Episodes 20,23–28.

Steurbaut, E. & Sztr

akos, K. 2008: Danian/Selandian boundary

criteria and North Sea Basin-Tethys correlations based on cal-

careous nannofossil and foraminiferal trends in SW France.

Marine Micropaleontology 67,1–29.

Tori, F. & Monechi, S. 2013: Lutetian calcareous nannofossil

events in the Agost section (Spain): implications toward a revi-

sion of the Middle Eocene biomagnetostratigraphy. Lethaia 46,

293–307.

Turco, E., Iaccarino, S.M., Foresi, L.M., Salvatorini, G., Rifor-

giato, F. & Verducci, M. 2011: Revisiting the taxonomy of the

intermediate stages in the Globigerinoides-Praeorbulina lineage.

Stratigraphy 8, 163–186.

Van Couvering, J.A., Castradori, D., Cita, M.B., Hilgen, F.J. &

Rio, D. 2000: The base of the Zanclean Stage and of the Plio-

cene Series. Episodes 23, 179–187.

Vandenberghe, N., Hilgen, F.J., Speijer, R.P., Ogg, J.G., Grad-

stein, F.M., Hammer, O., Hollis, C.J. & Hooker, J.J. 2012: The

Paleogene Period. In Gradstein, F.M., Ogg, J.G., Schmitz,

M.D. & Ogg, G.M. (eds): The Geologic Time Scale 2012, 855–

921. Elsevier, Oxford.

Varol, O. 1998: Paleogene. In Bown, P.R. (ed.): Calcareous Nan-

nofossil Biostratigraphy, 200–224. British Micropalaeontologi-

cal Society Publication Series. Chapman & Hall, Berlin.

462 Agnini et al. LETHAIA 50 (2017)

Wade, B.S., Pearson, P.N., Berggren, W.A. & P€

alike, H. 2011:

Review and revision of Cenozoic tropical planktonic forami-

niferal biostratigraphy and calibration to the geomagnetic

polarity and astronomical time scale. Earth-Science Reviews

104, 111–142.

Wade, B.S., Fucek, V.P., Kamikuri, S.I., Bartol, M., Luciani, V. &

Pearson, P.N. 2012: Successive extinctions of muricate plank-

tonic foraminifera (Morozovelloides and Acarinina) as a candi-

date for marking the base Priabonian. Newsletters on

Stratigraphy 45, 245–262.

Walker, M., Joahnsen, S., Rasmussen, S.O., Popp, T., Steffensen,

J.-P., Gibbard, P., Hoek, W., Lowe, J., Andrews, J., Bj€

orck, S.,

Cwynar, L.C., Hughen, K., Kershaw, P., Kromer, B., Litt, T.,

Lowe, D.J., Nakagawa, T., Newnham, R. & Schwander, J. 2009:

Formal deﬁnition and dating of the GSSP (Global Stratotype

Section and Point) for the base of the Holocene using the

Greenland NGRIP ice core, and selected auxiliary records.

Journal of Quaternary Science 24,3–17.

Wallich, G.C. 1861: Remarks on some novel phases of organic

life at great depths in the sea. The Annals and Magazine of Nat-

ural History Series 3,52–58.

Wallich, G.C. 1877: Observations on the coccosphere. The Annals

and Magazine of Natural History 19, 342–350.

Westerhold, T., R€

ohl, U., Laskar, J., Rafﬁ, I., Bowles, J., Lourens,

L.J. & Zachos, J.C. 2007: On the duration of Magnetochrons

C24r and C25n, and the timing of early Eocene global warm-

ing events: implications from the ODP Leg 208 Walvis Ridge

depth transect. Paleoceanography,22, PA2201.

Westerhold, T., R€

ohl, U., Rafﬁ, I., Fornaciari, E., Monechi, S.,

Reale, V., Bowles, J. & Evans, H.F. 2008: Astronomical

calibration of the Paleocene time. Palaeogeography, Palaeocli-

matology, Palaeoecology 257, 377403.

Westerhold, T., R€

ohl, U., Frederichs, T., Bohaty, S.M. &

Zachos, J.C. 2015: Astronomical calibration of the geologi-

cal timescale: closing the middle Eocene gap. Climate of

Past 11, 1181–1195.

Young, J.R. 1998: Neogene. In Bown, P.R. (ed.): Calcareous Nan-

nofossil Biostratigraphy, 225–265. British Micropalaeontologi-

cal Society Publication Series. Chapman & Hall, Berlin.

Young, J.R., Geisen, M., Cros, L., Kleijne, A., Sprengel, C., Pro-

bert, I. & Østergaard, J. 2003: A guide to extant coccol-

ithophore taxonomy. Journal of Nannoplankton Research

Special Issue 1,1–121.

Zachos, J.C., Pagani, M., Sloan, L.C., Billups, K. & Thomas, E.

2001: Trends, rhythms, and aberrations in global climate

65 Ma to present. Science 292, 686–693.

Supporting Information

Additional Supporting Information may be found in

the online version of this article:

Appendix S1. Taxonomic and bibliographic infor-

mation on Figures 6 and 7.

LETHAIA 50 (2017) Cenozoic nannofossils in chronostratigraphy 463

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Jun 2024

The biostratigraphy of the Tonasa Formation in the Jeneponto Regency of South Sulawesi, Indonesia, is still poorly known, and there are barren ages, such as much of the Oligocene to Early Miocene. The Tonasa Formation is well exposed along the coast of the Jeneponto Regency, in which the Karama area consists of the most important outcrops of this formation which in this area consists of interbedded marl and limestone. Our study focuses on the biostratigraphy of the Karama area section A based on nannofossil. Samples were collected by measured stratigraphy methods and then subjected to investigation using smear slides. The assemblages of species were determined by semiquantitative analysis. Data analysis obtained three nannofossil datums (boundaries): The First Occurrence (FO) of Sphenolithus pseudoradians NP19/NP20), the First Occurrence of Sphenolithus distentus (CP.16/CP.17), and the Last Occurrence (LO) Sphenolithus predistentus (NP.23/NP.24. The zonal boundary was determined based on calcareous nannoplankton; the Late Eocene to Middle Oligocene boundary of the Tonasa Formation was found in this section. Interestingly, throughout this period, the marker species in this section is Sphenolithus . In addition, the presence of Sphenolithus , Discoaster , and Zygrhablithus bijugatus indicated that the basin was in warm water condition.

Calcareous Nannofossils and Paleoclimatic Evolution Across the Eocene‐Oligocene Transition at IODP Site U1509, Tasman Sea, Southwest Pacific Ocean

Article

Full-text available

Feb 2024

The Eocene‐Oligocene transition (EOT; ∼34 Ma) was one of the most prominent global cooling events of the Cenozoic, coincident with the emergence of continental‐scale ice‐sheets on Antarctica. Calcareous nannoplankton experienced significant assemblage turnover at a time of long‐term surface ocean cooling and trophic conditions, suggesting cause‐effect relationships between Antarctic glaciation, broader climate changes, and the response of phytoplankton communities. To better evaluate the timing and nature of these relationships, we generated calcareous nannofossil and geochemical data sets (δ¹⁸O, δ¹³C and %CaCO3) over a ∼5 Myr stratigraphic interval recovered across the EOT from IODP Site U1509 in the Tasman Sea, South Pacific Ocean. Based on trends observed in the calcareous nannofossil assemblages, there was an overall decline of warm‐oligotrophic communities, with a shift toward taxa better adapted to cooler more eutrophic conditions. Assemblage changes indicate four distinct phases caused by temperature decrease and variations in paleocurrents: late Eocene warm‐oligotrophic phase, precursor diversity‐decrease phase, early Oligocene cold‐eutrophic phase, and a steady‐state cosmopolitan phase. The most prominent shift in the assemblages occurred during the ∼550 kyr‐long precursor diversity‐decrease phase, which has relatively high bulk δ¹⁸O and %CaCO3 values, and predates the phase of maximum glacial expansion (Earliest Oligocene Glacial Maximum–EOGM).

2021 1P Ricketts Et Al

Article

Full-text available

Feb 2024

The informal upper Paleocene to lower Eocene Red Bank group crops out in several areas of the Cayo and Orange Walk districts of northern Be-lize including the study area of the present report, which is the area around the oil fields of Spanish Lookout and Never Delay. Previous studies, which assigned the wrong age to the Red Bank group, described the Red Bank as mainly a clay (or soft claystone) deposit containing minor carbonate and evaporite beds and nodules. However, our present research, which relies on new petrographic and cartographic techniques, revealed that the Red Bank group is a complex stratigraphic unit of open estuarine origin that has a depositional history closely linked to global climatic and eustatic events. Well-log correlation in the study area around the Spanish Lookout and Never Delay oil fields suggests that the Red Bank unconformably overlies the Upper Cretaceous Barton Creek limestones. In fact, the clay deposits of the Red Bank fill caverns and karstic features within the upper part of the Bar-ton Creek limestones, and thick clay accumulations lie within karstic paleo-valleys such as the long, northeast-trending, fault-bounded karstic valley within the study area.

Middle Miocene volcanic flare up preceding and synchronous with the Langhian/Serravallian sea‐level decline in the North Pannonian Basin: Insights from 40 Ar / 39 Ar dating, geo‐seismic analysis and 3D visualization of the subterranean Kráľová stratovolcano

Article

Full-text available

Jan 2024

The Pannonian Basin System originated from the collision of the African and European tectonic plates, followed by the Miocene extensional collapse that led to the development of a back‐arc basins. Accurate dating is essential to comprehend the tectono‐volcanic evolution of the region, particularly in the under‐studied Danube Basin. Single‐grain ⁴⁰ Ar/ ³⁹ Ar dating has revealed that volcanic activity in the Danube Basin commenced around 14.1 million years ago, aligning with previous biostratigraphic and radioisotope data from nearby volcanic fields. The initial Middle Miocene pyroclastic deposits were generated by intermediate high K calc‐alkaline magmas, contributing significantly to the deposition of thick layers of fine vitric tuffs. The timing and chemistry of the volcanism are consistent with the Badenian rift phase in the Middle Miocene within the Carpathian–Pannonian region, suggesting an intraplate back‐arc volcanic environment. Three‐dimensional imaging has exposed the buried Kráľová stratovolcano, revealing its impressive scale with a thickness between 2620 and 5000 m and a base diameter of 18–30 km. Such dimensions place it among the ranks of the world's largest stratovolcanoes, indicating its substantial impact on the evolution of the Carpathian–Pannonian area. The complex formation history of the stratovolcano points to multiple phases of growth. Furthermore, the basin controlling Mojmírovce‐Rába fault's intersection with the stratovolcano implies that fault activity was subsequent to the volcanic activity, being younger than 14.1 million years. Regional age data consistently indicates that volcanic activity in the Danube Basin reached its zenith just prior to and during the lower/upper Badenian sea‐level fall (Langhian/Serravallian). K‐metasomatism is unique to the stratovolcanic structures and is not observed in the wider regional setting. This study supports the notion of an intricate, interconnected subterranean intrusive system within the stratovolcano, underscoring the complex interplay between geological structures and volcanic processes.

Multi-Elemental Chemostratigraphy, Sequence Development, Depositional History, and Environmental Impor-tance of Early Eocene Red Beds (Kuldana Formation

Article

Apr 2024
J EARTH SCI-CHINA

The Eocene Kuldana Formation (KF) in the Yadgar area of Pakistan, comprises a diverse range of sedimentary facies, including variegated red beds of shales, mudstones, and sandstones, as well as interbedded limestone and marl. In this study, we conducted an integrated micropaleontologi-cal, sedimentological, mineralogical, and geochemical investigation to determine the depositional setting , biochronology, provenance, and paleoclimate of the KF. The study identified six lithofacies and six microfacies, which indicate a variety of environments ranging from floodplains and channels to the margins and shallow marine settings. The nannofossil biostratigraphy places the KF in the Early Eo-cene, more precisely the NP10 zone (Ypresian), and the fossil zone of benthic foraminifera classifies the study section as the Shallow Benthic Zone SBZ-8 (Middle Ilerdian 2). In terms of petrography, the KF sandstone was classified as litharenite and feldspathic litharenite, while the QtFL diagram suggests a recycled orogen. Geochemical proxies indicate an oxidizing environment, a high-to-low regular sedi-mentation rate, moderate-to-intense chemical weathering in the source region, and a warm-humid to dry climate during the deposition of KF. Overall, the findings suggest that the deposition of KF marks the end of Neo-Tethys due to the Early Eocene Indian-Kohistan collision and that the uplifting of the Himalayas provided the source for the deposition of KF in the foreland basin. The study provides new insights into the depositional environment, biochronology, provenance, and paleoclimate of KF, and highlights the potential for red beds as reliable indicators of oxygenation levels in proximity to mineral deposits.

Reference Sections (Kartli, Georgia)

Chapter

Full-text available

Dec 2023

Biostratigraphy of calcareous nannofossils and their distribution in Tonasa Formation, Mallasoro area Jeneponto, South Sulawesi

Article

Full-text available

Dec 2023

The age studies of the Tonasa Formation have been carried out from various relative ages, including using large foraminifera, small foraminifera, and nannofossil. Field and laboratory data were collected to observe the age and distribution of nannofossils in the study area. The results of observations from nannofossils in the Mallasoro section of the Jeneponto area are as many as 20 species were identified and examined in three markers of Sphenolithus pseudoradians (NP.22-NP.24), and the Last Occurrence of Dictyococcites scrippsae (NP.25-NN. 1). The age zonation of Tonasa Formation in this area is determined from the three datums is the Late Oligocene to Early Miocene (NP. 21 – NN.1) or correlated to CP.16c – CP.19a. The nannofossil abundances are distributed from bottom to top of the section is common to a few species, they are Cyclicargolithus floridanus, Sphenolithus moriformis , and Sphenolithus predistentus , respectively. Then followed by Zygrhabilithus bijugatus, Discoaster deflandrei , Dictyococcites scrippsae , and Coccolithus pelagicus in rare to present distributions and the others are present to single.

Lithostratigraphy, Stable Isotope Stratigraphy and Calcareous Nannofossils Biostratigraphy of the Danian-Thanetian at Nukhul, Sinai, Egypt

Article

Dec 2023

Atef M. Kasem

Expedition 342 summary

Chapter

Mar 2014

The Geological Time Scale

Article

Oct 2006

Felix M. Gradstein

This lecture reviews Geologic Time Scale 2004 (Gradstein, Ogg et al., 2004; Cambridge University Press), constructed and detailed by 40 geoscience specialists, and indicates how it will be further refined. Since Geologic Time Scale 1989 by Harland et al., many developments have taken place: (1) Stratigraphic standardization through the work of the International Commission on Stratigraphy (ICS) has greatly refined the international chronostratigraphic scale. In some cases, traditional European-based stages have been replaced with new subdivisions that allow global correlation. (2) New or enhanced methods of extracting high-precision age assignments with realistic uncertainties from the rock record. These have led to improved age assignments of key geologic stage boundaries and other global correlation horizons. (3) Orbital tuning has greatly refined the Neogene, and improved parts of Paleogene and Mesozoic. (4) Statistical techniques of compiling integrated global stratigraphic scales within geologic periods. Anticipated advances to the Geologic Time Scale during the next 8 years include: a geologically realistic Precambrian scale, formal definition of all Phanerozoic stage boundaries, orbital tuning of polarity chrons and biostratigraphic events for entire Cenozoic and Cretaceous, a detailed database of high-resolution radiometric ages that includes “best practice” procedures, full error analysis, monitor ages and conversions, resolving age dating controversies (e.g., zircon statistics and possible reworking) across Devonian/Carboniferous, Permian/Triassic, and Anisian/Ladinian boundaries, improved and standardized dating of several ‘neglected’ intervals (e.g., Upper Jurassic – Lower Cretaceous, and Carboniferous through Triassic, and detailed integrated stratigraphy for Upper Paleozoic through Lower Mesozoic. The geochronological science community and ICS are focusing on these issues. A modified version of the time scale to accompany the standardization (boundary definitions and stratotypes) of all stages is planned for 2008 (to be presented at the 33th International Geologic Congress in Oslo), with a totally revised version of GTS available in 2012.

Expedition 368X summary

Chapter

Apr 2020

The Pliocene-Pleistocence Boundary

Article

Jun 1985
EPISODES

The Global Stratotype Section and Point (GSSP) for the base of the Chattian Stage (Paleogene System, Oligocene Series) at Monte Cagnero, Italy

Article

Mar 2018
EPISODES

The GSSP for the base of the Chattian Stage (Paleogene System, Oligocene Series) is defined at meter level 197 in the Monte Cagnero section, which belongs to the pelagic succession of the Umbria-Marche basin (Urbania, central Italy: 43°38′47.81″N-12°28′03.83″E). This level with an astronomical age of 27.82 Ma coincides with the highest common occurrence of the planktonic foraminifer Chiloguembelina cubensis at the base of planktonic foraminiferal O5 Zone and falls in the upper part of calcareous nannofossil NP24 Zone, in the lower part of dinocyst Dbi Zone, and in the lower Chron C9n. The proposal was approved by the International Subcommission of Paleogene Stratigraphy in July 2015, approved by the International Commission of Stratigraphy in August 2016, and ratified by the International Union of Geological Sciences in September 2016.

Calcareous nannoplankton‐Leg 43, Deep Sea Drilling Project

Article

Jan 1979

Cenozoic geochronology

Article

Jan 1965

Palaeocene calcareous nannofossil biostratigraphy

Article

Jan 1989

Osman Varol

Low to middle latitude Paleogene calcareous nannofossil biozonation and biochronology

Article

Jul 2014

Claudia Agnini

Paleogene calcareous nannofossils from the Kerguelen Plateau, Leg 120

Article

Jan 1992

M.-P. Aubrey

Calcareous nannofossils are abundant in the Paleogene sediments recovered during Ocean Drilling Program Leg 120. Although no continuous Paleogene section was obtained, Sites 747 through 751 complemented each other so as to provide a virtually complete composite stratigraphic section. The calcarous nannofossil biostratigraphy at Sites 747, 748, and 749 is discussed. Correlation of calcareous nannofossil biozones and magnetozones at these sites suggests some diachrony with low-latitude areas, as well as on a regional basis. Changes in calcareous nannofossil diversity throughout the Paleogene are analyzed and interpreted as reflecting major paleoclimatic events. -Author

Calcareous nannofossil biostratigraphy: historical background and application in Cenozoic chronostratigraphy

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