Content uploaded by Silvia Iaccarino
Author content
All content in this area was uploaded by Silvia Iaccarino
Content may be subject to copyright.
The GSSP of the Tortonian Stage, which per definition
marks the base of the Tortonian and, hence, the bound-
ary between the Serravallian and Tortonian Stages of
the Middle and Upper Miocene Subseries, has recently
been defined and ratified by the IUGS. The boundary
stratotype-section is Monte dei Corvi (Italy) where the
Tortonian GSSP is now formally at the mid-point of the
sapropel of small-scale sedimentary cycle no. 76, close
to the last common occurrences (LCOs) of the calcare-
ous nannofossil Discoaster kugleri and the planktonic
foraminifer Globigerinoides subquadratus and associ-
ated with the short normal subchron C5r.2n. The GSSP
level coincides closely with oxygen isotope event Mi-5
and the associated glacio-eustatic sea-level low-stand
of supercycle T3.1 and concurrent deep-sea hiatus NH4,
and is dated astronomically at 11.608 Ma. The Monte
Gibliscemi section is accepted as an auxiliary boundary
stratotype because the better preservation of the cal-
careous microfossils in this section enables quantitative
analyses and the construction of a stable isotope record.
Introduction
The aim of this paper is to announce the ratification of the Global
boundary Stratotype Section and Point (GSSP) of the Tortonian
Stage. Together with the Messinian, the Tortonian represents the
twofold subdivision of the Upper Miocene Subseries in the Global
Standard Chronostratigraphic scale.
A brief description of the stratotype-section, the boundary and
the various stratigraphic tools available for global correlation of the
Tortonian GSSP is presented. Additional information is found in the
original proposal (Hilgen et al., 2002) and in the literature referred to
in this paper. The integrated stratigraphic data and astronomical tun-
ing of the sedimentary cycles, which underlie the selection of Monte
dei Corvi as boundary stratotype-section, are reported in detail else-
where (Hilgen et al., 2003). The proposal (Hilgen et al., 2002) was
forwarded to all SNS voting members in 2002 for postal ballot and
almost unanimously accepted. Following the results of the postal
ballot, a formal recommendation of SNS was submitted to the Sec-
retary General of the ICS in spring 2003. Official acceptance by the
ICS and ratification by the IUGS Executive Committee were
obtained later that year.
Background and motivation
During the last years, much progress has been made in the standard-
ization of the Neogene part of the Global Standard Chronostrati-
graphic scale by defining the GSSPs of all Pliocene Stages
(Castradori et al., 1998; Rio et al., 1998; Van Couvering et al., 2000)
and the youngest Messinian Stage of the Miocene (Hilgen et al.,
2000a). The logical next step is to select and define the GSSP for the
next older stage in the Miocene, the Tortonian (Mayer-Eymar,
1858). This step is greatly facilitated by the progress recently made
in establishing orbital-tuned integrated stratigraphic frameworks for
the Middle/Upper Miocene both in the Mediterranean (Hilgen et al.,
1995, 2000b, 2003) and in the open ocean (Shackleton and
Crowhurst, 1997; Shackleton et al., 1999).
The Tortonian has been consistently used as a global stage in
almost all standard geological time scales including the most recent
ones (e.g., Harland et al., 1990; Berggren et al., 1995). Nevertheless,
considerable uncertainty existed about the guiding criteria and age of
the base Tortonian. In addition the proven unsuitability of the histor-
ical stratotype section some 10 km south of Tortona necessitated the
search for an alternative boundary stratotype section. Of the candi-
date sections, Monte dei Corvi located on the Adriatic coast of north-
ern Italy proved to be the only section that provided a good to excel-
lent magnetostratigraphy, calcareous plankton biostratigraphy and
cyclostratigraphy in the critical interval. But before introducing
Monte dei Corvi and the integrated stratigraphic data of this section,
we will start with a condensed review of the history of the Tortonian
stage concept.
A brief historical review of the Tortonian
Original definition of the Tortonian (Mayer-Eymar,
1858)
The Tortonian Stage ("Tortonische Stufe"), named after the
town of Tortona in northern Italy, was introduced by Mayer-Eymar
March 2005
6
by Frederik Hilgen
1
, Hayfaa Abdul Aziz
1,2
, David Bice
3
, Silvia Iaccarino
4
,
Wout Krijgsman
2
, Klaudia Kuiper
1,5
, Alessandro Montanari
6
, Isabella Raffi
7
,
Elena Turco
4
, and Willem-Jan Zachariasse
1
The Global boundary Stratotype Section and
Point (GSSP) of the Tortonian Stage (Upper
Miocene) at Monte Dei Corvi
1 Stratigraphy/Paleontology, Dept. of Earth Sciences, Utrecht University, The Netherlands (Email:fhilgen@geo.uu.nl)
2 Paleomagnetic Lab. “Fort Hoofddijk”, Dept. of Earth Sciences, Utrecht University, The Netherlands
3 Department of Geology, Carleton College, Northfield MN 55057, USA
4 Dipartimento di Scienze della Terra, Universita degli Studi di Parma, Parma, Italy
5 Department of Isotope Geochemistry, Vrije Universiteit Amsterdam, The Netherlands
6 Osservatorio Geologico di Coldigioco, 62020 Frontale di Apiro, Italia
7 Dip. di Scienze della Terra, Univ. “G. D’Annunzio”, 66013 Chieti Scalo, Italy
Episodes, Vol. 28, no. 1
7
Figure 1 (continued) B. Chronostratigraphic proposals using planktonic foraminifer biostratigraphy.
Figure 1 Historiacal review of the Miocene chronostratigraphic subdivision. A. chronostratigraphic proposals before the development
of calcareous plankton.
A
B
in 1858 as "Blaue Mergel mit Conus canaliculatus und Ancillaria
glandiformis von Tortona". In his original definition of the Torton-
ian, Mayer-Eymar included:
-– Marine strata of Tortona (Italy), Baden (Vienna Basin) and
Cabrières d'Aigues (Vaucluse, Fr.);
-– Continental beds with Hipparion at Eppelsheim; beds at Cucurou
(Mont-Leberon, Vaucluse, France) and Orignac (Hautes
Pyrénées, France) with the same fauna.
It is important to realise that Mayer-Eymar extended the Tor-
tonian up to the base of the Piacenzian considered to be basal Plio-
cene of age (Figure 1). In 1868, he decapitated his Tortonian Stage
by introducing the term Messinian to embody the regressive, brack-
ish-water strata above the marine Tortonian (Figure 1). Despite this
complex history, the term Tortonian was soon adopted after its intro-
duction partly because of the many influential papers on the sub-
division of the Tertiary published by Mayer-Eymar (Figure 1).
Tortonian stratotype section (Gianotti, 1953)
The Rio Mazzapiedi-Castellania section located between the
village of Sant' Agata Fossili and the town of Alessandria, some 10
km south of Tortona (Figure 2), was designated as the Tortonian
stratotype by Gianotti (1953) following the geological study of the
type area by Gino (1953). Relevant studies in the area have subse-
quently been carried out by Vervloet (1966), Clari and Ghibaudo
(1979) and Ghibaudo et al. (1985) to which the reader is referred for
detailed information. The Tortonian stratotype mainly consists of
marly sediments (the Sant' Agata Fossili marls of Ghibaudo et al.,
1985), which overlie the deltaic sandstones (Mutti E., personal com-
munication) of the Serravalle Formation (Figure 2). Clari and
Ghibaudo (1979) subdivided the Sant' Agata marls into two mem-
bers. The lower member is composed of a 180 m thick succession of
bioturbated fine sandstones alternating with clayed siltstones while
the upper member consists of an 80 m thick succession of blue-grey
hemipelagic silty marls with thin turbidites in its upper part. Biota
and lithofacies associations indicate an outer shelf and slope envi-
ronment respectively.
The Rio Mazzapiedi-Castellania section is unanimously con-
sidered as the reference for the nominate time interval. It should be
noted however that according to Gianotti (1953) the type Tortonian
included the so-called “Marne tabacco a Cerizi” underlying the
evaporitic sequence and yielding poor and oligotypical foraminiferal
faunas. The younger end of the Tortonian of Gianotti (1953) has
been decapitated later by the lowering of the Messinian base (Cita et
al., 1965; d'Onofrio et al., 1975).
March 2005
8
Figure 1 (continued) C. Position of the Miocene stages versus magnetostratigraphy in the most widely used chronostratigraphic
schemes proposed between 1970 and 1995.
Figure 2 Geological map of the Tortonian type area and location of
the Tortonian stratotype section in the valley of Rio Mazzapiedi and
Rio Castellania between the villages of Sant’ Agatha Fossili (after
Clari and Ghibaudo, 1979). 1 = alluvial deposits; 2 = Lugagnano
Clays; 3 = Cassano Spinola Conglomerate; 4 = Gessoso-Solfifera
Formation; 5 = Alosio Conglomerate; 6 = S. Agata Fossili Marl
(upper member); 7 = S. Agata Fossili Marl (lower member); 8 =
Serravalle Sandstone; 9 = Apennine units; and 10 = trace of the
Tortonian stratotype section.
C
The Tortonian is consistently reported as a
global stage in all the geological time scales (Figure
1). In addition there existed a general consensus that
the Tortonian base is approximated by the first
occurrence (FO) of the planktonic foraminifer
Neogloboquadrina acostaensis (see below).
Timing of the base of the Tortonian and
top of the Serravallian stratotype
The Serravallian/Tortonian (S/T) boundary was
commonly placed at or close to the N. acostaensis
FO (Cita and Blow, 1969 and Rio et al., 1997 for
recent references). This bioevent was first recorded
by Cita et al. (1965) from the basal part of the Tor-
tonian historical stratotype section of Rio Mazza-
piedi-Castellania (Figure 3) and was coincident with
the base of the G. mayeri-G. nepenthes Zone. Later
Cita and Blow (1969), who considered the FO of N.
acostaensis as the evolutionary appearance from G.
continuosa (N15/N16 boundary of Blow, 1969),
indicated that this event best approximated the base
of the Tortonian. The basal part of the Tortonian was
assigned to nannofossil zone NN9 on the basis of the
presence of the zonal marker Discoaster hamatus
(Mazzei, 1977).
These zonal assignments are conflicting, how-
ever, with the common practise to place the
N15/N16 boundary at or close to the base of NN8
(see Rio et al., 1997). Recent data from the Monte
Gibliscemi section (Sicily) even indicate that the N.
acostaensis FO actually falls within zone NN7 in the
Mediterranean as previously suggested by Foresi et
al. (1998). This indicates that the so-called N.
acostaensis FO at Rio Mazzapiedi-Castellania does
not represent the true first occurrence of this taxon,
as recently confirmed by the presence of rare N.
acostaensis in the top part of the Serravalle Sand-
stones immediately below the base of the Tortonian
stratotype (Miculan, 1997; Foresi et al., 1998). Evi-
dently, the base of the Tortonian stratotype postdates
the N. acostaensis FO.
The base of the Tortonian stratotype is older
than the first regular occurrence (FRO) of N.
acostaensis of Foresi et al. (1998). But the position
of the N. acostaensis FRO above the D. hamatus FO
in the Tortonian stratotype (Foresi et al., 1998) con-
flicts with findings from Monte Gibliscemi which
indicate that the D. hamatus/bellus entry is delayed
in the Mediterranean with respect to low latitudes
and postdates the N. acostaensis FRO by several 100
kyrs (Hilgen et al., 2000b). Samples from the Tor-
tonian stratotype studied by Foresi et al. (1998) were
checked to solve this discrepancy by means of a
semi-quantitative analysis and following the taxo-
nomic criteria outlined by Hilgen et al. (2000b), the
N. acostaensis FRO is positioned lower in the succession near the
base of the Tortonian and below the D. hamatus FO. Moreover, the
dominant right coiling of the neogloboquadrinids from the lower
part of the Tortonian and the underlying Serravalle sandstones indi-
cates that there is not a discernable hiatus at the base of the Torton-
ian stratotype and that the top part of the Serravalle sandstones post-
dates the first influx of the neogloboquadrinids at Monte Gibliscemi
in which the coiling direction is essentially random. These findings
further imply that the base of the type Tortonian postdates the last
occurrence (LO) of Paragloborotalia mayeri (P. siakensis of Foresi
et al., 1998) and, as a consequence, that all reported occurrences of
this taxon in the Tortonian stratotype should be considered
reworked. In conclusion, the Tortonian base in the historical strato-
type corresponds almost exactly with the N. acostaensis FRO as
defined at Monte Gibliscemi and dated astronomically at 10.554 Ma
(see Hilgen et al., 2000b). This observation is more or less consistent
with Müller (1975) who examined the “Serravallian of the Rio Maz-
zapiedi section" and referred it with certainty to NN7, and probably
also to NN8 and the lower part of NN9 (reported only in the abstract
of the paper) although the latter could not be confirmed due to the
lack of samples from the uppermost part of the Serravalle sandstones
in this section.
The top of the Serravallian stratotype in the Serravalle Scrivia
section can be dated at 11.8 Ma by linear extrapolation of the sedi-
mentation rate between the Sphenolithus heteromorphus LO (13.5
Ma; Rio et al., 1997) and the last common occurrence (LCO) of Cal-
cidiscus premacintyrei (12.3 Ma; Rio et al., 1997). This admittedly
Episodes, Vol. 28, no. 1
9
Figure 3 Summary of the calcareous plankton biostratigraphic data from the
Tortonian stratotype (from Rio et al., 1997). F = Planktonic foraminifer, N =
Calcareous nannofossil. The most recent data have not been included (see text).
rough age estimate indicates that there is no overlap in time between
the top of the Serravallian stratotype and the base of the Tortonian
stratotype and that all bioevents in the interval between 11.8 and
10.554 Ma are potentially suitable for delimiting the S/T boundary.
Selecting the most suitable section and level for
defining the Tortonian GSSP
In the Neogene, orbital tuned cyclostratigraphies (Hilgen et al.,
1995, 2000a; Lourens et al., 1996) play an important role in addition
to conventional criteria outlined by the International Commission on
Stratigraphy (ICS) in the revised guidelines for establishing global
chronostratigraphic standards (Remane et al., 1996). This extra cri-
terion is added here because all ratified Neogene GSSPs are defined
at lithological marker beds that are astronomically dated. In this way
they are tied via first-order calibrations to the standard geological
time scale once this time scale is underlain by astronomical tuning as
is already the case for the Plio-Pleistocene (Berggren et al., 1995).
This implies that other requirements being equal cyclostratigraphy
will play a critical role in selecting the most suitable section and
level for defining the Tortonian GSSP.
Selecting the guiding criterion for defining the
boundary
According to the available biostratigraphic data from the histor-
ical stratotype sections (Serravallian and Tortonian), the Tortonian
GSSP should be defined somewhere in the interval between the Cal-
cidiscus praemacintyrei LCO (= top Serravallian type section, Rio et
al., 1997) and the Neogloboquadrina acostaensis FRO (= base Tor-
tonian type section, Hilgen et al., 2000b). Three different options
were considered for locating the boundary by the Working Group on
the Tortonian GSSP:
1) to place the boundary coincident with the FRO of N. acostaensis
dated astronomically at 10.544 Ma in the Monte Gibliscemi sec-
tion. The boundary would closely coincide with the base of the
Tortonian in the historical stratotype section and approximately
with a major turnover in the calcareous nannofossils marked by
the appearance of five-rayed discoasters (Discoaster bellus
group) in the low latitudes;
2) to place the boundary at or close to the base of the long normal
interval of C5n.2n. This reversal has been dated astronomically at
11.043 Ma in the continental section of Orera in Spain (Abdul
Aziz et al., 2003). In the open ocean the boundary would be
approximated by the Coccolithus miopelagicus LCO and the
Catinaster coalitus FO; and
3) to place the boundary at or close to the Discoaster kugleri and
Globigerinoides subquadratus LCOs dated at 11.604 and 11.539
Ma in the Monte Gibliscemi section (Hilgen et al., 2000b). These
events have similar ages in the Case Pelacani and Tremiti Islands
sections (Caruso et al., 2002; Lirer et al., 2002).
The first option is regarded less favourable in view of the rela-
tively low global correlation potential even though the boundary
would in that case coincide closely with the Tortonian base in the
historical stratotype. The second option was seriously taken into
consideration also because it would result in a duration of the Tor-
tonian that deviates less from that of the next younger Messinian
stage and, probably, the older Serravallian stage. But this option has
not been adopted because calcareous plankton events close to the
boundary are considered less suitable for global recognition of the
boundary. The C. miopelagicus LCO is diachronous while C. coali-
tus is a less reliable marker in the Mediterranean and its
presence/absence in the open ocean is environmentally controlled.
The third option was preferred because of the high correlation
potential using multiple stratigraphic tools (planktonic foraminifera,
calcareous nannoplankton, δ
18
O, magnetostratigraphy, sequence
stratigraphy) which can be applied in widely different settings. The
selected calcareous plankton events appear to be synchronous
between the Mediterranean and the low-latitude open ocean on the
basis of the existing astronomical age models. In addition, the D.
kugleri LCO is tightly linked to the short normal subchron C5r.2n
(Raffi et al., 1995). Moreover, this event coincides closely with the
Mi-5 isotope event and the associated glacio-eustatic sea-level low-
stand (TB3.1) and deep-sea hiatus NH4.
The use of D. kugleri needs some taxonomic clarification. Our
concept of D. kugleri fits exactly with the original description of the
species (Martini and Bramlette, 1963) and has the same variability in
morphology as documented in the original paper with a large and flat
central area without a central knob. However, the identification of D.
kugleri is problematical when preservation is poor because other dis-
coasters having a similar morphology (e.g., D. musicus with D. san-
miguelensis as a junior synonym) can be confused with overgrown
D. kugleri. In addition, a higher than average sample resolution is
necessary to reliably detect this event.
G. subquadratus is a taxon easily recognizable and its test mor-
phology makes it readily identifiable from other species in this inter-
val. The G. subquadratus LCO is an event easily detectable by the
sharp decrease of the species. Only rare and scattered specimens are
found at younger levels. The event is very close to the G. obliquus
FCO.
Selecting the section to define the boundary
The historical stratotype section of Rio Mazzapiedi-Castellania
is considered unsuitable for defining the Tortonian GSSP because
the section has not been astronomically tuned and contains consider-
able numbers of reworked microfossils. In addition it does not con-
tain the boundary interval selected above. Tuned candidate sections
for defining the GSSP are the Monte Gibliscemi and Case Pelacani
sections on Sicily (southern Italy: Hilgen et al., 2000b; Caruso et al.,
2002), the Monte dei Corvi section in northern Italy (Hilgen et al.,
2003) and the San Nicola section on Tremiti islands (Adriatic Sea,
Italy: Lirer et al., 2002).
Of all candidate sections Monte dei Corvi is the only section
that is demonstrable continuous, shows a near lack of tectonic dis-
turbance, is excellently exposed and easily accessible and can be
unambiguously tuned in the critical interval across the boundary.
The Monte Gibliscemi section is tectonically severely disturbed
while the Case Pelacani and San Nicola sections are less well
exposed in the boundary interval. Clearly this strengthens the case
for Monte dei Corvi to define the Tortonian GSSP as previously sug-
gested by Montanari et al. (1997) and Odin et al. (1997). The section
can be correlated cyclostratigraphically in detail to sections on Sicily
(Monte Gibliscemi, Case Pelacani) and the Tremiti Islands (San
Nicola). Serious shortcomings are the moderate to poor preservation
of the calcareous plankton. The preservation problem certainly ham-
pers to establish a reliable stable isotope record but detailed bios-
tratigraphic correlations to other Mediterranean sections marked by
a better preservation are straightforward. The initial lack of a reliable
magnetostratigraphy in the critical interval (Montanari et al., 1997;
Hilgen et al., 2003) has since been overcome by a detailed paleo-
magnetic analysis of a new high-resolution sample set (unpubl.
data).
The Tortonian GSSP at Monte Dei Corvi
The Monte dei Corvi Beach section is exposed in the coastal cliffs of
Monte dei Corvi located 5 km SE of Ancona (Italy) at a latitude of
43°35'12" North and a longitude of 13°34'10" East of Greenwich.
The section is very easy to reach from Ancona and is freely and eas-
ily accessible to scientists interested in studying the section (Figures
4, 5). The section can best be reached via the trail that starts at La
Sardella some 100 m east of Monte dei Corvi (Figure 4).
The coastal cliff exposures of Monte dei Corvi contain the Mid-
dle to Upper Miocene part of the succession exposed along the
Cònero Riviera. They were first measured and studied in detail by
Sandroni (1985), and subsequently re-measured and sampled by
March 2005
10
Montanari et al., 1988). The sequence is exposed in three main out-
crops (see Montanari et al., 1997 and Figure 4): 1) the Monte dei
Corvi Beach section along the beach; 2) the La Sardella - Monte dei
Corvi High Cliff composite section high up on the cliff, along the
scarp of a large landslide, and; 3) the La Vedova section along the
seashore bluffs and cliffs at the locality known as La Vedova. Inte-
grated stratigraphic data are provided by Montanari et al. (1997) who
studied the entire composite section and by Hilgen et al. (2003) who
focused their attention exclusively on the excellently exposed Monte
dei Corvi Beach section (Figure 5). It is the latter section that con-
tains the proposed Tortonian GSSP (Figures 5, 6).
Geological setting
The Miocene succession of Monte dei Corvi is particularly suit-
able for integrated stratigraphic studies because it occupied a relative
external position with respect to the developing Apenninic orogen at
that time (Montanari et al., 1997). For this reason the succession
remained pelagic throughout most of the Miocene, being affected by
the NE-ward prograding orogenic front of the Apennines and its
associated flysch-like sedimentation at a late, post Miocene stage
(Montanari et al., 1997).
Stratigraphic succession
The entire succession exposed along the cliffs from Ancona to
Porto Nouvo extends from the Aquitanian into the Pliocene and con-
Episodes, Vol. 28, no. 1
11
Figure 4 Location map for the boundary stratotype section of
Monte dei Corvi (A) and (B) the auxiliary boundary stratotype
section of Monte Gibliscemi (after Hilgen et al., 2003). The partial
sections that combined make up the Gibliscemi composite are in
stratigraphic order F, D, C, B and A (see Hilgen et al., 1995, 2000b
for details).
Figure 5 Photograph of the older part of the Monte dei Corvi
Beach section of Montanari et al. (1997) and of the
Serravallian/Tortonian boundary interval. The S/T boundary and
numbered basic sedimentary cycles are indicated (cycle numbers
after Hilgen et al., 2003). The arrow marks the Tortonian GSSP
and the (empty) bottle the Ancona ash bed.
Figure 6 Lithological log of the Monte dei Corvi Beach section
(after Hilgen et al., 2003). The two ash beds are indicated by a R
(Respighi level) and A (Ancona level). I and II refer to two thick
intervals in which it is difficult to ascertain the individual basic
sedimentary cycles.
tains the Bisciaro (Aquitanian to Langhian), Schlier (Langhian to
Tortonian), Euxinic Shale and Gessoso Solfifera (Messinian) For-
mations of the northern Apennines (Montanari et al., 1997). In this
paper we concentrate on the Serravallian and Lower Tortonian part
of the succession exposed along the eastern slopes and in the coastal
cliffs of Monte dei Corvi described in detail by Montanari et al.
(1997) and Hilgen et al. (2003). This interval is particularly well
exposed in the Monte dei Corvi Beach section of Montanari et al.
(1997). This section contains the upper part of the marly Schlier For-
mation (upper part calcareous member and basal part marly mem-
ber) and consists of a cyclic alternation of greenish-grey marls,
whitish marly limestones and brown coloured organic-rich layers
(sapropels). In addition, two biotite-rich volcanic ash layers, named
Respighi and Ancona, are present (Figure 6). This part of the suc-
cession is underlain by the calcareous marls of the massive member
of the middle Schlier exposed in section La Vedova and overlain by
marls and euxinic shales of the Euxinic Shale Formation exposed in
section La Sardella (Montanari et al., 1997).
Depositional environment
The depositional environment
remained (hemi)pelagic throughout the suc-
cession exposed in the Monte dei Corvi
Beach section. Restricted conditions leading
to the deposition of the so-called euxinic
shales and eventually evaporites associated
with the Messinian salinity crisis start higher
up in the succession. Bottom water condi-
tions changed cyclically between oxic
(marls) and anoxic or dysoxic (sapropel lay-
ers).
Calcareous nannofossil
biostratigraphy
Calcareous nannofossils are abundant
but their preservation is generally moder-
ate to poor, being better in the sapropel
layers. Quantitative biostratigraphic stud-
ies of the calcareous nannofossils were
carried out by Montanari et al. (1997) and
Hilgen et al. (2003; Figure 7). Combining
the results of these studies, the following
succession of events is recorded (in strati-
graphic order): Cyclicargolithus flori-
danus LO, Calcidiscus macintyrei FO, C.
premacintyrei LO, Discoaster kugleri
FCO and LCO, last regular occurrence
(LRO) of Coccolithus miopelagicus, Heli-
cosphaera walbersdorfensis LO and H.
stalis FCO, D. bellus FO, and D. hamatus
FO. This order of events is essentially the
same as found in other Mediterranean sec-
tions such as Monte Gibliscemi (Hilgen et
al., 2000b), Case Pelacani (Caruso et al.,
2002) and San Nicola (Lirer et al., 2002).
The GSSP closely coincides with the Dis-
coaster kugleri LCO and thus with the
MNN7b-c zonal boundary in terms of the
standard Mediterranean zonation (Raffi et
al., 2003). It falls within Zone NN7 of the
standard low-latitude zonation of Martini
(1971) and in Zone CN6 of the Okada and
Bukry (1980) zonation.
Planktonic foraminiferal
biostratigraphy
Planktonic foraminifera are usually abundant but their preser-
vation is often moderate to poor. The qualitative studies of Coccioni
et al. (1992; 1994) of the entire composite section allowed to identify
all the events employed in the regional zonal scheme of Iaccarino
and Salvatorini (1982) and Iaccarino (1985), whereas only few
events of the standard low-latitude zonation of Blow (1969) were
recognised. The entire composite section ranges from Zone N8 to
N17 (Montanari et al., 1997).
The semi-quantitative biostratigraphic analysis presented in
Hilgen et al. (2003) focused on the Monte dei Corvi Beach section
and allowed the recognition of some additional events in the bound-
ary interval (Figure 7). The FO of the Neogloboquadrina group,
including N. acostaensis, previously recognised at Monte Giblis-
cemi and dated at 11.781 Ma, was also found at Monte dei Corvi,
dated at 11.762 Ma. The G. subquadratus LCO dated at 11.539 Ma
in the Monte Gibliscemi section was found at a slightly older level at
Monte dei Corvi (at 11.593 Ma). It is preceeded by the Neoglobo-
quadrina group FO and the Paragloborotalia mayeri (sensu Foresi
et al., 1998) LO and succeeded by the G. apertura-G. obliquus group
March 2005
12
Figure 7 Calcareous plankton biostratigraphy of the Monte dei Corvi Beach section (after
Hilgen et al., 2003). No useful data indicates that the marker species has not been counted in
this interval because the data would have had no biostratigraphic significance.
FRO, the P. siakensis (= P. mayeri sensu Hilgen et al., 2000b) LO
and the large-sized N. atlantica FO. The GSSP falls within the P.
siakensis Zone of Iaccarino (1985), coincides with the boundary
between N. continuosa and G. menardii Zones of Foresi et al.
(1998), and the boundary between N. atlantica praeatlantica and P.
siakensis Zones of Sprovieri et al. (2002). Application of the stan-
dard low-latitude zonation of Blow (1969) is rather useless in view
of the strong diachroneity of some of the zonal marker events. For
example the zonal markers for N14/N15 and N15/N16 fall apart at
Ceara Rise (equatorial Atlantic) but overlap in the Mediterranean. At
Ceara Rise the guiding criteria for the base Tortonian fall slightly
above the G. nepenthes FO (Turco et al., 2002) which event marks
the N13/N14 zonal boundary of Blow (1969). In the Carribean Sea,
the boundary also falls in the lower part of N14 (Chaisson and
D’Hondt, 2000).
Magnetostratigraphy
A detailed paleomagnetic study of the Monte dei Corvi Beach
section has been carried out by Montanari et al. (1997) and Hilgen et
al. (2003) with the main purpose to determine the magnetic reversal
stratigraphy of the section. Applying standard demagnetisation tech-
niques, Montanari et al. (1997) concluded that the magnetic intensity
was too weak to yield useful information on the magnetic polarity
and that the natural remanent magnetisation (NRM) was already
largely removed at temperatures of 200°C. Most samples revealed
southwesterly declinations and negative inclinations, but these direc-
tions were considered as an overprint.
A pilot study of a limited number of oriented hand-samples
similarly revealed weak to very weak NRM intensities, but also
some levels with opposite reversed and normal polarity directions.
Subsequent analysis of a more detailed sample set made it possible
to isolate a characteristic low-temperature component marked by
dual polarities (Hilgen et al., 2003). Plotting the ChRM directions
resulted in a magnetostratigraphy for the upper part of the section
that could be calibrated to the GPTS of Cande and Kent (1995) and
ranges from C5n.2n up to C4r.2r (Figure 8).
At first, the lower part of the section, including the Serravallian-
Tortonian boundary interval, did not produce a reliable magnetostra-
tigraphy in first instance despite the fact that some short reversed
intervals were recorded (Figure 8). But the initial lack of a reliable
magnetostratigraphy in the critical interval has been overcome in the
meantime by a more detailed paleomagnetic analysis of a new sam-
ple set with a much higher resolution (unpubl. data). The resulting
magnetostratigraphy for the critical middle part of the section can be
calibrated straightforwardly to the GPTS of Cande and Kent (1995)
and Lourens et al. (2004) and ranges from C5n.2n down to at least
C5An.1n. The boundary is, as anticipated, closely associated with —
the base of— the short normal subchron C5r.2n. Finally, the tuned
ages for the newly determined magnetic reversal boundaries at
Monte dei Corvi are in very good to excellent agreement with the
tuned ages for the same reversals in the continental Orera section in
Spain (Abdul Aziz et al., 2003).
Episodes, Vol. 28, no. 1
13
Figure 8 Magnetostratigraphy of the Monte dei Corvi Beach
section and calibration to the GPTS of Cande and Kent (1995;
based on Hilgen et al., 2003). Note that new unpublished
magnetostratigraphic data have not been included in the present
figure. Due to the higher resolution, the new data much better
constrain the position of the reversals boundaries in the upper
(~35 m) part of the section. Moreover, they provide reliable data
for the middle part of the section (i.e. from ~50 to ~80 m),
pinpointing all polarity reversal down to the base of C5An.1n and
confirming the link between the Tortonian GSSP and C5r.2n.
Figure 9 Astronomical tuning of the basic sedimentary cycles in
the Serravallian/Tortonian boundary interval in the Monte dei
Corvi Beach section to precession and insolation (after Hilgen et
al., 2003).
Cyclostratigraphy and astrochronology
The Monte dei Corvi Beach section is composed of a cyclic
alternation of marls, marly limestones and organic-rich beds (Mon-
tanari et al., 1997). The basic small-scale cycle is a couplet (between
0.3 and 1.0 m thick) which consists of an indurated whitish marly
limestone and a softer grey to greenish-grey marl. Brownish to
blackish coloured organic-rich beds termed sapropels are frequently
but not always intercalated in the limestones. Basic cycles have been
labelled from the base of the section upward by assigning consecu-
tive numbers to the limestone beds or the corresponding sapropels
(Figure 6).
Larger-scale cycles can be distinguished in addition and com-
prise both small-scale and large-scale sapropel clusters. Small-scale
clusters contain 2 to 4 sapropels (and 5–6 basic cycles); large-scale
clusters contain several small-scale clusters (and up to 20 basic
cycles). Finally a cycle of intermediate-scale is recognised by repet-
itive sapropel patterns in every other basic cycle. Previous studies of
marine sections of Late Miocene to Pleistocene age in the Mediter-
ranean (Hilgen, 1991; Lourens et al., 1996) showed that similar
sapropel patterns reflect the astronomical cycles of precession (basic
cycle), obliquity (intermediate cycle) and eccentricity (larger-scale
cycles). Using the same phase relations as established for the
younger sapropels, the sedimentary cycles in the Monte dei Corvi
Beach section were tuned to the precession and insolation time series
of the La93 solution (Laskar, 1990; Laskar et al., 1993). This tuning
provides astronomical ages for all the sedimentary cycles, calcare-
ous plankton bioevents, magnetic reversals and ash beds recorded in
the section (Figure 9). It shows that the entire beach section ranges
from 13.4 to 8.5 Ma and that the Tortonian GSSP has an astronomi-
cal age of 11.608 Ma (Hilgen et al., 2003; see Figure 9). Application
of the new full numerical solution La2004 (Laskar et al., 2004) will
not seriously affect the tuning and result in minor changes in the
astronomical ages only (in the order of several kyr).
Note that our preferred tuning deviates from the eccentricity
tuning proposed by Cleaveland et al. (2002). The latter tuning is
based on a high-resolution carbonate record and is consistent with
the previously published
40
Ar/
39
Ar biotite ages from the ash beds,
but not with unpublished sanidine ages for the Ancona bed (see
below). However, their tuning can easily be modified as to fit the
tuning of Hilgen et al. (2003) and followed in the present paper.
Ar/Ar chronology
The composite sequence at Monte dei Corvi contains numerous
ash layers, most of which are concentrated in a relatively short inter-
val across the Tortonian/Messinian boundary. Two biotite-bearing
ash layers, named Respighi and Ancona, are found in the Monte dei
Corvi Beach section, the latter one being intercalated only 2 m below
the proposed GSSP. Fresh unaltered biotites from both these ash lay-
ers have been dated using the incremental-heating
40
Ar/
39
Ar tech-
nique (Montanari et al., 1997). For the Respighi layer, the preferred
mean isochron age (of 3 out of 4 experiments) arrived at 12.86 ± 0.16
Ma, while a weighted average of two plateau ages (of a single exper-
iment) of 11.43 ± 0.20 Ma was obtained for the Ancona bed. These
ages were calculated relative to an age of 27.84 Ma for the Fish
Canyon Tuff sanidine monitor dating standard and they arrive at
12.94 and 11.51 Ma if the recently published age of 28.02 Ma for
this standard is applied (Renne et al., 1998). These ages are slightly
but significantly younger than the astronomical ages of 13.296 and
11.688 Ma for the same ash layers (Hilgen et al., 2003). However a
recent intercalibration study arrives at an astronomically calibrated
age of 28.24 ± 0.01 Ma for the FCT sanidine while single fusion
experiments on sanidine from the Ancona ash yield an age of 11.68
±0.02 Ma that is virtually identical to the preferred astronomical age
(Kuiper, 2003; Kuiper et al., 2005).
Sr-isotope stratigraphy
The Sr-isotope composition of whole rock, isolated foraminif-
eral tests and fish teeth has been analysed in samples from the
Monte dei Corvi Beach and La Sardella sections (Montanari et al.,
1997). The isotope composition of the whole rock samples from the
Monte dei Corvi Beach section is generally consistent with
87
Sr/
86
Sr values in pelagic carbonates from the open ocean. On the
other hand, samples (of widely different materials) from the
Messinian La Sardella section exhibit Sr-isotope ratios that are sig-
nificantly lower than those obtained from the open ocean. This
deviation can best be explained by an increasing isolation of the
Mediterranean Basin, or partially so, from the world's oceans (Mon-
tanari et al., 1997).
Stable isotopes
Unfortunately, a reliable stable isotope record can not be
obtained due to the moderate to poor preservation of the foramin-
iferal tests. The Monte dei Corvi Beach section can be correlated
cyclostratigraphically in detail with the Monte Gibliscemi section
(Figure 10) from which a planktic and benthic isotope record is
available (Turco et al., 2001; Figure 11). This correlation shows
March 2005
14
Figure 10 Integrated cyclostratigraphic and biostratigraphic
correlations between the Monte dei Corvi Beach section (MdC)
and the Monte Gibliscemi section (MG) (after Hilgen et al., 2003).
The part of the Gibliscemi composite shown here is based on
partial sections F, D, C and B (see Hilgen et al., 1995, 2000b for
details). Numbered calcareous plankton events refer to: (1)
Neogloboquadrina group FO, (2) G. subquadratus LCO, (3) P.
siakensis LO, (4) Neogloboquadrina group second influx, (5) N.
atlantica large-sized FO, (6) N. atlantica large-sized LO, (7)
Neogloboquadrina dextral to sinistral coiling shift, (8) G.
partimlabiata LO, (9) Neogloboquadrina sinistral to dextral
coiling shift, a) D. kugleri FCO, b) D. kugleri LCO, and c) C.
miopelagicus LRO. (Dashed) arrows mark major (minor) influxes
of large-size N. atlantica.
that the Tortonian GSSP slightly predates a short interval marked
by heavier δ
18
O values that corresponds to the Mi-5 isotope event
of Miller et al. (1991). This event supposedly reflects a temporary
increase in Antarctic ice volume linked to minimum amplitude
variations in the 1.2 myr obliquity cycle (Turco et al., 2001).
Completeness of the section
The unambiguous orbital tuning of the sedimentary cycles in
the boundary interval cannot be explained other than that the succes-
sion is continuous. The tuning provides a highly accurate age of
11.608 Ma for the boundary. The section can further be correlated
bed-to-bed to other marine sections in the Mediterranean (Figures
10, 11). The cyclostratigraphic correlations are confirmed in detail
by the high-resolution calcareous plankton biostratigraphy, thus pro-
viding another argument for the continuity of the succession. Sedi-
ment accumulation rates can be accurately determined and are in the
order of 3-4 cm/kyr in the boundary interval.
Definition, position, and identification of the
boundary
The Serravallian/Tortonian boundary and hence the base of the
Tortonian Stage is defined at the midpoint of the sapropel layer of
small-scale sedimentary cycle no. 76 in the Monte dei Corvi Beach
(Figure 6; Hilgen et al., 2003). The level coincides almost exactly
with the base of the short normal subchron C5r.2n and the last com-
mon occurrences (LCOs) of the calcareous nannofossil Discoaster
kugleri and the planktonic foraminifer Globigerinoides subquadra-
tus (Figure 7), and is located stratigraphically 2 m above the Ancona
ash layer (Figure 8). The level has been assigned an astronomical age
of 11.608 Ma (Figure 9). We selected the sapropel midpoint instead of
sapropel base (as has been common practise in defining GSSPs of Neo-
gene stages up to now) because it is the midpoint that is assigned the
age of the correlative peak in the astronomical target curve. The mid-
point of the sapropel layer of cycle 76 will be marked in the field. Iden-
tification of the GSSP and re-sampling of the section are greatly facili-
tated by the readily identifiable sedimentary cycle pattern in the field.
Auxiliary boundary stratotype
We designate section Gibliscemi, exposed along the southern
slopes of Monte Gibliscemi located on Sicily (Italy) as an auxil-
iary boundary stratotype for the Serravallian-Tortonian boundary.
This designation is meant to overcome the problem of the poor to
moderate preservation of the calcareous microfossils observed at
Monte dei Corvi, which also prevents us from establishing a reli-
able stable isotope record. The Gibliscemi section has been corre-
lated cyclostratigraphically in detail ("bed-to-bed") to the Monte
dei Corvi section, the cyclostratigraphic correlations being con-
firmed by the calcareous plankton biostratigraphy (Figure 10). At
Monte Gibliscemi the S/T boundary is placed at the mid-point of
the grey marl bed of small-scale cycle -75 in subsection D located
at 24.67 m in the Gibliscemi composite of Hilgen et al. (2000b).
The marl bed correlates with the sapropel of cycle 76 at Monte dei
Corvi (Figure 10) and coincides closely with the D. kugleri LCO.
In addition, four volcanic ash layers are found in the basal part of
section Gibliscemi which contain sanidine in a datable fraction.
The Ar/Ar ages for the most suitable of the ash layers are in agree-
ment with the astronomical ages for these layers (Kuiper, 2003;
Kuiper et al., 2005).
The integrated calcareous plankton biostratigraphy and
astronomical tuning of the section were presented in Hilgen et al.
(2000b) while the quantitative planktonic foraminifer record, and
the planktonic and benthic stable isotope records were published
in Turco et al. (2001). The planktonic and benthic isotope records
are punctuated by two episodes of δ
18
O increase (Figure 11)
which have been assigned astronomical ages of around 11.4 and
10.4 Ma and correspond to the Mi5 and Mi6 events of Miller et al.
(1991). The expression of the Mi5 event thus slightly postdates
the S/T boundary as proposed here.
Regional exportation of the boundary
Integrated stratigraphic correlations of the Tortonian GSSP to
other Mediterranean sections are straightforward and unambiguous.
High-resolution cyclostratigraphic correlations are confirmed in
detail by the position of calcareous plankton events. This applies
both to major bio-events such as the Discoaster kugleri FCO and
LCO, the G. subquadratus LCO, and the Neogloboquadrina group
FO and to secondary events such as the G. apertura-G. obliquus
group FRO. The magnetobiostratigraphic record of continental sec-
tions in Spain shows that the GSSP predates the Hipparion FO with
a minimum age of 11.1 Ma (Garcés et al., 1997) and, thus, the Arag-
onian/Vallesian stage boundary by some amount of time.
Global exportation of the boundary
The concurrence of the Tortonian GSSP with subchron C5r.2n
has now been confirmed by new magnetostratigraphic data from the
boundary stratotype section itself. The association allows identifica-
tion of the boundary in continental settings lacking a direct biostrati-
graphic control. In the marine realm, the D. kugleri and G. subquad-
ratus LCOs appear to be synchronous between the Mediterranean
type area and the low-latitude open ocean (Backman and Raffi,
1997; Hilgen et al, 2000b; Turco et al., 2002).
Stable isotopes yet provide another useful correlation tool. The
boundary slightly predates the Mi-5 isotope event of Miller et al.
(1991) dated astronomically at 11.4 Ma in the Monte Gibliscemi sec-
tion (Turco et al., 2001; Figure11) and the associated glacio-eustatic
sea-level low-stand of supercycle T3.1 (Haq et al., 1987) and con-
current deep-sea hiatus NH4 of Keller and Barron (1983). The
boundary further coincides almost exactly with the Barstovian-
Clarendonian Mammal Age boundary in North America (Wood-
burne and Swisher, 1995; Alroy, 2002).
Episodes, Vol. 28, no. 1
15
Figure 11 Benthic and planktonic isotope records of the Monte
Gibliscemi section showing the position of event Mi-5 (from Turco et al.,
2001). The part of the Gibliscemi composite shown is based on partial
sections F and D (see Hilgen et al., 2000b for details).
References
Abdul Aziz, H., Hilgen, F.J., Krijgsman, W., and Calvo, J.P., 2003, An astro-
nomical polarity time scale for the late middle Miocene based on cyclic
continental sequences: J. Geophys. Res., v. 108, 2159.
Alroy, J., 2002, A quantitative North American Time Scale (http:
//www.nceas.ucsb.edu/~alroy).
Backman, J., and Raffi, I., 1997, Calibration of Miocene nannofossil events
to orbitally-tuned cyclostratigraphies from Ceara Rise: Proc. ODP, Sci.
Res., v. 154, pp. 83-99.
Berggren, W.A., Kent, D.V., Swisher, C.C., and Aubry, M.-P., 1995, A
revised Cenozoic geochronology and chronostratigraphy, in Geochronol-
ogy, Time Scales and Global Stratigraphic Correlation, SEPM Spec.
Publ., v. 54, pp. 129-212.
Blow, W.H., 1969, Late middle Eocene to Recent planktonic foraminiferal
biostratigraphy, in Bronniman, P., and Renz, R.R., eds., Proc. First. Int.
Conf. Planktonic Microfossils, Geneva, 1967, v. 1, pp. 199-422, Leiden.
Cande, S.C., and Kent, D.V., 1995, Revised calibration of the Geomagnetic
Polarity Time Scale for the Late Cretaceous and Cenozoic: J. Geophys.
Res., v. 100, pp. 6093-6095.
Caruso, A., Sprovieri, M., Bonanno, A., and Sprovieri, R., 2002, Astronomi-
cal calibration of the Serravallian-Tortonian Case Pelacani section
(Sicily, Italy), in Iaccarino, S., ed., Integrated stratigraphy and paleo-
ceanography of the Mediterranean Middle Miocene: Riv. It. Paleont.
Strat., v. 108, pp. 297-306, Milano.
Castradori, D., Rio, D., Hilgen, F.J., and Lourens, L.J., 1998, The Global
Standard Stratotype section and Point (GSSP) of the Piacenzian Stage
(Middle Pliocene): Episodes, v. 21, pp. 88-93.
Chaisson, W.P., and d’Hondt, S.L., 2000, Neogene planktonic foraminifer
biostratigraphy at Site 999, western Carribean Sea, in Leckie, R.M., Sig-
urdsson, H., Acton, G.D., and Draper, G., eds., Proc. ODP, Sci. Results,
v. 165: College Station TX (Ocean Drilling Program), pp. 19-56.
Cita, M.B., Premoli Silva, I., and Rossi, R., 1965, Foraminiferi planctonici
del Tortoniano-tipo: Riv. Ital. Paleontol. Stratigr., v. 71, pp. 217-308.
Cita, M.B., and Blow, W.H., 1969, The biostratigraphy of the Langhian, Ser-
ravallian and Tortonian Stages in the type-sections in Italy: Riv. It. Pale-
ont. Strat., v. 75, pp. 549-603.
Clari, P., and Ghibaudo, G., 1979, Multiple slump scars in the Tortonian type
area (Piedmont Basin, Northwestern Italy): Sedimentology, v. 26, pp.
719-730.
Cleaveland, L.C., Jensen, J., Goese, S., Bice, D.M., and Montanari, A., 2002,
Cyclostratigraphic analysis of pelagic carbonates at Monte dei Corvi
(Ancona, Italy) and astronomical correlation of the Serravallian-Torton-
ian boundary: Geology, v. 30, pp. 931-934.
Coccioni, R., Di Leo, C., and Galeotti, S., 1992, Planktonic foraminiferal bio-
stratigraphy of the upper Serravallian-lower Tortonian Monte dei Corvi
section (NE Apennines, Italy), in Montanari, A., et al., eds., Conferenza
interdiscplinare di geologia sull’Epoca miocenica con enfasi sulla
sequenza umbro-marchigiana, Ancona 1992, Miocene Columbus Project.
Abstr. and Field trips, pp. 53-56.
Coccioni, R., Galeotti, S., and Di Leo, R., 1994, The first occurrence of
Neogloboquadrina atlantica (Berggren) in the Mediterranean: Giorn.
Geol., v. 56, pp. 127-138.
d’Onofrio, S., Giannelli, L., Iaccarino, S., Morlotti, E., Romeo, M., Salva-
torini, G., Sampò, M., and Sprovieri, R., 1975, Planktonic foraminifera of
the Upper Miocene from some Italian sections and the problem of the
lower boundary of the Messinian: Boll. Soc. Paleont. It., v. 14, pp. 177-
196.
Foresi, L.M., Iaccarino, S., Mazzei, R., and Salvatorini, G., 1998, New data
on Middle to Late Miocene calcareous plankton biostratigraphy in the
Mediterranean area: Riv. It. Paleont. Strat., v. 104, pp. 95-114.
Garcés, M., Cabrera, L., Agusti, J., and Parés, J.M., 1997, Old world first
appearance datum of "Hipparion" horses: Late Miocene large mammal
dispersal and global events: Geology, v. 25, pp. 19-22.
Gianotti, A., 1953, Microfaune della serie tortoniana del Rio Mazzapiedi-
Catellania (Tortona - Alessandria): Riv. It. Paleont., Mem. VI, pp. 167-
308.
Ghibaudo, G., Clari, P., and Perello, M., 1985, Lithostratigrafia, sedimen-
tologia ed evoluzione tettonico-sedimentaria dei depositi miocenici del
margine sud-orientale del Bacino Terziario Ligure-Piemontese (valli
Borbera, Scrivia e Lemme): Boll. Soc. Geol. Ital., v. 104, pp. 349-397.
Gino, G.F., 1953, Osservazioni geologiche sui dintorni di S. Agata Fossili:
Riv. It. Paleont. Strat., Mem. VI, pp. 1-23.
Harland, W.B., Amstrong, R., Cox, A.V., Craig, L., Smith, A., and Smith, D.,
1990, A Geological Time Scale 1989, Cambridge Univ. Press, Cam-
bridge, 263 pp.
Haq, B.U., Hardenbol., J., and Vail, P.R., 1987, Chronology of fluctuating
sea levels since the Triassic: Science, v. 235, pp. 1156-1167.
Hilgen, F.J., 1991, Astronomical calibration of Gauss to Matuyama sapropels
in the Mediterranean and implication for the Geomagnetic Polarity Time
Scale: Earth Planet. Sci. Lett., v. 104, pp. 226-244.
Hilgen, F.J., Krijgsman, W., Langereis, C.G., Lourens, L., Santarelli, A., and
Zachariasse, W.J., 1995, Extending the astronomical (polarity) time scale
into the Miocene: Earth Planet. Sci. Lett., v. 136, pp. 495-510.
Hilgen, F.J., Iaccarino, S., Krijgsman, W., Villa, G., Langereis, C.G., and
Zachariasse, W.J., 2000a, The Global boundary Stratotype Section and
Point (GSSP) of the Messinian Stage (Uppermost Miocene): Episodes, v.
23, pp. 172-178.
Hilgen, F.J., Krijgsman, W., Raffi, I., Turco, E., and Zachariasse, W.J.,
2000b, Integrated stratigraphy and astronomical calibration of the Ser-
ravallian/Tortonian boundary section at Monte Gibliscemi, Sicily: Mar.
Micropal., v. 38, pp. 181-211.
Hilgen, F.J., Iaccarino, S., Krijgsman, W., Montanari, A., Raffi, I., Turco, E.,
and Zachariasse, W.J., 2002, The Global Stratotype Section and Point
(GSSP) of the Tortonian Stage (Upper Miocene): A proposal
(http://www.geo.uu.nl/sns/).
Hilgen, F.J., Abdul Aziz, H., Krijgsman, W., Raffi, I., and Turco, E., 2003,
Integrated stratigraphy and astrochronology of the Serravallian and lower
Tortonian at Monte dei Corvi (Middle-Upper Miocene, Northern Italy):
Palaeogeogr., Palaeoclim., Palaeoecol., v. 199, pp. 229-264.
Iaccarino, S., and Salvatorini, G., 1982, A framework of planktonic foramin-
iferal biostratigraphy for early Miocene to late Pliocene in the Mediter-
ranean area: Paleontol. Stratigr. ed Evol., v. 2, pp. 115-125.
Iaccarino, S., 1985, Mediterranean Miocene and Pliocene planktic foraminif-
era, in Bolli, H.M., Saunders, J.B., and Perch-Nielsen, K., eds., Plankton
Stratigraphy, Cambridge Univ. Press, pp. 283-314.
Keller, G., and Barron, J.A., 1983, Paleoceanographic implications of Mio-
cene deep-sea hiatuses: Geol. Soc. Am. Bull., v. 94, pp. 590-613.
Kuiper, K., 2003, Direct intercalibration of radioisotopic and astronomical
time in the Mediterranean Neogene: Geologica Ultraiectina, v. 235, 223
pp (see also http://www.geo.vu.nl/users/kuik).
Kuiper, K., Hilgen, F.J. and Wijbrans, J.R., 2005, Radioisotopic dating of the
Tortonian GSSP: implications for intercalibration of
40
Ar/
39
Ar and astro-
nomical dating methods: Terra Nova (in press).
Laskar, J., 1990, The chaotic motion of the solar system: A numerical esti-
mate of the size of the chaotic zones: Icarus, v. 88, pp. 266-291.
Laskar, J., Joutel, F., and Boudin, F., 1993, Orbital, precessional, and insola-
tion quantities for the Earth from -20 Myr to +10 Myr: Astron. Astro-
phys., v. 270, pp. 522-533.
Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A.C.M., and Lev-
rard, B., 2004, A long term numerical solution for the insolation quanti-
ties of the Earth: Astron. & Astrophys., v. 428, 261–285.
Lirer, F., Caruso, A., Foresi, L.M., Sprovieri, M., Bonomo, S., Di Stefano,
A., Di Stefano, E., Iaccarino, S.M., Salvatorini, G., Sprovieri, R., and
Mazzola, S., 2002, Astrochronological calibration of the upper Serraval-
lian-lower Tortonian sedimentary sequence at Tremiti Islands (Adriatic
Sea, Southern Italy), in Iaccarino, S., ed., Integrated stratigraphy and
paleoceanography of the Mediterranean Middle Miocene: Riv. It. Pale-
ont. Strat., v. 108, pp. 241-256, Milano.
Lourens, L., Hilgen, F.J., Zachariasse, W.J., van Hoof, A.A.M.,
Antonarakou, A., and Vergnaud-Grazzini, C., 1996, Evaluation of the
Plio-Pleistocene astronomical time scale: Paleoceanography, v. 11, pp.
391-413.
Lourens, L.J., Hilgen, F.J., Laskar, J., Shackleton, N.J., and Wilson, D., 2004
The Neogene Period. in Gradstein, F., Ogg, J., et al., (eds), A Geologic
Time Scale 2004, Cambridge Univ. Press, UK.
Martini, E., 1971, Standard Tertiary and Quaternary calcareous nannoplank-
ton zonation: Proc. II Planktonic Conf., Roma 1970, v. 2, pp. 739-785.
Martini, E., and Bramlette, M.N., 1963, Calcareous nannoplankton from the
experimental Mohole drilling: J. Paleontol., v. 37, pp. 845-856.
Mayer-Eymar, K., 1858, Versuch einer neuen Klassification der Tertiär
gebilde Europa's, Verhandl. der Allgemeinen Schweiz. Ges. f. gesammt.
Naturwissensch., Trogen, pp. 165-199.
Mayer-Eymar, K., 1868, Tableau synchronistique des terrains Tertiaires
supérieurs, IV ed., Zürich.
Mazzei, R., 1977, Biostratigraphy of the Rio Mazzapiedi-Castellania section
(type section of the Tortonian) based on calcareous nannoplankton: Att.
Soc. Tosc. Sci. Nat. Mem., v. 84, pp. 15-24.
Miculan, P., 1997, Planktonic foraminiferal biostratigraphy of the Tortonian
historical stratotype, Rio Mazzapiedi-Castellania section, northwestern
Italy, in Montanari, A., Odin, G.S., and Coccioni R., eds., Miocene
stratigraphy: An integrated approach, Devel. Palaeontol. Stratigr., v. 15,
pp. 97-106.
March 2005
16
Miller, K.G., Wright, J.D., and Fairbanks, R.G., 1991, Unlocking the Ice
House: Oligocene-Miocene oxygen isotopes, eustacy and marginal ero-
sion: J. Geophys. Res., v. 96, pp. 6829-6848.
Montanari, A., Langenheim, V.E., and Coccioni, R., 1988, Stratigraphy and
geochronological potential of the pelagic and hemipelagic sequence of
the northeastern Apennines: A research note: Bull. Liais. Inf., Project
196, 7, pp. 17-23.
Montanari, A., Beaudoin, B., Chan, L.S., Coccioni, R., Deino, A., de Paolo,
D.J., Emmanuel, L., Fornaciari, E., Kruge, M., Lundblad, S., Mozzato,
C., Portier, E., Renard, M., Rio, D., Sandroni, P., and Stankiewicz, A.,
1997, Integrated stratigraphy of the Middle and Upper Miocene pelagic
sequence of the Cònero Riviera (Marche region, Italy), in Montanari, A.,
Odin, G.S., and Coccioni, R., eds., Miocene stratigraphy: An integrated
approach: Devel. Palaeontol. Stratigr., v. 15, pp. 409-450.
Müller, C., 1975, Calcareous nannoplankton from type Serravallian, Proc.
RCMNS, Bratislava, pp. 49-52.
Odin, G.S, Montanari, A., and Coccioni, R., 1997, Chronostratigraphy of
Miocene Stages: A proposal for the definition of precise boundaries, in
Montanari, A., Odin, G.S., and Coccioni, R., eds., Miocene stratigraphy:
An integrated approach: Devel. Palaeontol. Stratigr., v. 15, pp. 597-629.
Okada, H., and Bukry, D., 1980, Supplementary modification and introduc-
tion of code numbers to the low-latitude coccolith biostratigraphic zona-
tion (Bukry, 1973; 1975): Mar. Micropal., v. 51, pp. 321-325.
Raffi, I., Mozzato, C., Fornaciari, E., Hilgen, F.J., and Rio, D., 2003, Late
Miocene calcareous nannofossil biostratigraphy and astrobiochronology
for the Mediterranean region. Micropaleontology: v. 49, pp. 1-26.
Raffi, I., Rio, D., d'Atri, A., Fornaciari, E., Rocchetti, S., 1995, Quantitative
distribution patterns and biomagnetostratigraphy of Middle to Late Mio-
cene calcareous nannofossils from equatorial Indian and Pacific Oceans
(Legs 115, 130, and 118), Proc. ODP, Sci. Results: v. 138, 479-502.
Remane, J., Bassett, M.G., Cowie, J.W., Gohrbrandt, K.H., Richard Lane, H.,
Michelsen, O., and Naiwen, W., 1996, Revised guidelines for the estab-
lisment of global chronostratigraphic standards by the International Com-
mission on Stratigraphy (ICS): Episodes, v. 19, pp. 77-81.
Renne, P.R., Swisher, C.C., Deino, A., Karner, D.B., Owens, T.L., and
DePaolo, D.J., 1998, Intercalibration of standards, absolute ages and
uncertainties in
40
Ar/
39
Ar dating: Chem. Geol., v. 145, pp. 117-152.
Rio, D., Cita, M.B., Iaccarino, S., Gelati, R., and Gnaccolini, M., 1997,
Langhian, Serravallian, and Tortonian historical stratotypes, in Monta-
nari, A., Odin, G.S., and Coccioni, R., eds., Miocene stratigraphy: An
integrated approach: Devel. Palaeontol. Stratigr., v. 15, pp. 57-87.
Rio, D., Sprovieri, R., Castradori, D., and di Stefano, E., 1998, The Gelasian
Stage (Upper Pliocene: A new unit of the global standard chronostrati-
graphic scale: Episodes, v. 21, pp. 82-87.
Sandroni, P., 1985, Rilevamento geologico al 1:10.000 e litostratigrafia di
alcuni sezioni dello Schlier nel bacino marchigiano esterno e studio min-
eralogico e petrografica di una sezione riconstruita nell'anticlinale del
Conero, Thesis, Univ. of Urbino, 188 pp.
Shackleton, N.J., and Crowhurst, S., 1997, Sediment fluxes based on an
orbitally tuned time scale 5 Ma to 14 Ma, Site 926: Proc. ODP, Sci.
Results, v. 154, pp. 69-82.
Shackleton, N.J., Crowhurst, S.J., Weedon, G., and Laskar, J., 1999, Astro-
nomical calibration of Oligocene-Miocene time: Roy. Soc. Lond. Philos.
Trans., ser. A, v. 357, pp. 1909-1927.
Sprovieri, R., Bonomo, S., Caruso, A., di Stefano, A., di Stefano, E., Foresi,
L.M., Iaccarino, S.M., Lirer, F., Mazzei, R., and Salvatorini, G., 2002, An
integrated calcareous plancton biostratigraphic scheme and biochronol-
ogy for the Mediterranean Middle Miocene, in Iaccarino, S., ed., Inte-
grated stratigraphy and paleoceanography of the Mediterranean Middle
Miocene: Riv. It. Paleont. Strat. v. 108, pp. 337-353, Milano.
Turco, E., Hilgen, F.J., Lourens, L.J., Shackleton, N.J., and Zachariasse,
W.J., 2001, Punctuated evolution of global climate cooling during the late
Middle to early Late Miocene: High-resolution planktonic foraminiferal
and oxygen isotope records from the Mediterranean: Paleoceanography,
v. 16, pp. 405-423.
Turco, E., Bambini, A.M., Foresi, L.M., Iaccarino, S., Lirer, F., Mazzei, R.,
and Salvatorini, G., 2002, Middle Miocene high resolution calcareous
plankton biostratigraphy at Site 926 (Leg 154, equat. Atlantic Ocean):
paleoecological and paleobiogeographical implications: Geobios, v. 35,
pp. 257-276.
van Couvering, J.A., Castradori, D., Cita, M.B., Hilgen, F.J., and Rio, D.,
2000, The base of the Zanclean Stage and of the Pliocene Series:
Episodes, v. 23, pp. 179-187.
Vervloet, C.C., 1966, Stratigraphical and micropaleontological data on the
Tertiary of southern Piemont (northern Italy), Schotanus, Utrecht, 1-88
pp..
Woodburne, M.O., and Swisher, C.C., 1995, Land mammal high resolution
geochronology, intercontinental overland dispersals, sea-level, climate
and vicariance, in Berggren, W.A., et al., eds., Geochronology, time
scales and global stratigraphic correlation, Tulsa, Oklahoma, SEPM
(Society for Sedimentary Geology), pp. 335-364.
Episodes, Vol. 28, no. 1
17
Frederik Hilgen is the present chair
and past secretary of the
Subcommission on Neogene
Stratigraphy (SNS). His main
research interest lies in the
astronomical forcing of climate, in
cyclostratigraphy and in
constructing integrated high-
resolution stratigraphies and time-
scales.
Willem-Jan Zachariasse is the
former chair and secretary of the
Subcommission on Neogene
Stratigraphy and has a long
experience in Neogene stratigraphy
with special focus on the
Mediterranean. He is a planktonic
foraminiferal specialist and has a
great interest in paleoclimatology
and paleoceanography.
Silvia Iaccarino is a renowned
specialist on Neogene planktonic
foraminiferal biostratigraphy and
holds a life long interest in
stratigraphy and paleoceanography
of especially the Mediterranean
Neogene.
