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Ammonite biostratigraphy of the uppermost Hauterivian in the Betic Cordillera (SE Spain)

November 2003
Geobios 36(6)

November 2003
36(6)

DOI:10.1016/j.geobios.2002.12.001

Authors:

Miguel Company

University of Granada

José Sandoval

University of Granada

A detailed analysis of the stratigraphic distribution of ammonites from fourteen sections in the External Zones of the Betic Cordillera has enabled us to identify accurately the sequence of bioevents that take place throughout the uppermost Hauterivian and to propose a more precise biostratigraphic scheme for this interval. Thus, we have divided the two currently admitted zones (the Crioceratites balearis Zone and the Pseudothurmannia angulicostata auct. Zone) into several subzones. Four subzones can be recognised within the Cr. balearis Zone. The base of each subzone is defined by the first occurrence of one of four successive species belonging to the same Crioceratites lineage. These species are: Cr. balearis, Cr. binelli, Cr. krenkeli and Cr. angulicostatus. The Ps. ohmi Zone (which replaces the classical Ps. angulicostata Zone) can be divided into three subzones characterised by three successive species of the genus Pseudothurmannia: Ps. ohmi, Ps mortilleti (here considered as a senior synonym of Ps. catulloi) and Ps. picteti. According to the current definition, the first occurrence of Taveraidiscus hugii (OOSTER) marks the lower boundary of the Barremian stage. This event fits into a major faunal-renewal episode that begins in the upper part of the Ps. picteti Subzone.

Geographical and geological location of the studied sections. Fig. 1. Localisation géographique et géologique des coupes étudiées.

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Río Argos-1 section (X.Ag1). Lithological succession and ammonite distribution. Fig. 2. Coupe de Río Argos 1 (X.Ag1). Succession lithologique et distribution des ammonites.

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Arroyo Gilico section (X.V1). Lithological succession and ammonite distribution. Fig. 3. Coupe de Arroyo Gilico (X.V1). Succession lithologique et distribution des ammonites.

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Proposed zonation and ranges of the most significant ammonite species. Fig. 4. Zonation proposée et distribution stratigraphique des principales espèces d'ammonites.

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Content may be subject to copyright.

Ammonite biostratigraphy of the uppermost Hauterivian

in the Betic Cordillera (SE Spain)

Biostratigraphie d’ammonites de l’Hauterivien terminal

dans la Cordillère Bétique (sud-est de l’Espagne)

Miguel Company *, José Sandoval, José M.Tavera

Departamento de Estratigrafía y Paleontología, Facultad de Ciencias, Universidad de Granada, 18002 Granada, Spain

Received 2 October 2002; accepted 23 December 2002

Abstract

A detailed analysis of the stratigraphic distribution of ammonites from fourteen sections in the External Zones of the Betic Cordillera has

enabled us to identify accurately the sequence of bioevents that take place throughout the uppermost Hauterivian and to propose a more precise

biostratigraphic scheme for this interval. Thus, we have divided the two currently admitted zones (the Crioceratites balearis Zone and the

Pseudothurmannia angulicostata auct. Zone) into several subzones. Four subzones can be recognised within the Cr. balearis Zone. The base

of each subzone is deﬁned by the ﬁrst occurrence of one of four successive species belonging to the same Crioceratites lineage. These species

are: Cr. balearis, Cr. binelli, Cr. krenkeli and Cr. angulicostatus. The Ps. ohmi Zone (which replaces the classical Ps. angulicostata Zone) can

be divided into three subzones characterised by three successive species of the genus Pseudothurmannia: Ps. ohmi, Ps mortilleti (here

considered as a senior synonym of Ps. catulloi) and Ps. picteti. According to the current deﬁnition, the ﬁrst occurrence of Taveraidiscus hugii

(OOSTER) marks the lower boundary of the Barremian stage. This event ﬁts into a major faunal-renewal episode that begins in the upper part

of the Ps. picteti Subzone.

Résumé

L’analyse détaillée de la distribution stratigraphique des ammonites dans quatorze coupes localisées dans les Zones Externes de la

Cordillère Bétique nous a permis d’identiﬁer avec précision la séquence des bioévénements qui ont eu lieu durant l’Hauterivien sommital et

de proposer un schéma zonal précis pour cet intervalle. Ainsi, nous avons divisé les deux zones actuellement admises (Zone à Crioceratites

balearis et Zone à Pseudothurmannia angulicostata auct.) en plusieurs sous-zones. Quatre sous-zones ont pu être reconnues dans la Zone à Cr.

balearis. La base de chaque sous-zone est déﬁnie par la première apparition de l’une des quatre successives espèces appartenant à la même

lignée crioceratitique. Ces espèces sont : Cr. balearis, Cr. binelli, Cr. krenkeli et Cr. angulicostatus. La Zone à Ps. ohmi (qui vient remplacer

la Zone classique à Ps. angulicostata) peut être subdivisée en trois sous-zones caractérisées par trois espèces successives du genre

Pseudothurmannia : Ps. ohmi, Ps. mortilleti (considérée ici comme synonyme de Ps. catulloi)etPs. picteti. D’après la déﬁnition

actuellement admise, la première apparition de Taveraidiscus hugii (OOSTER) marque la limite inférieure de l’étage Barremien. Cet

événement coïncide avec un épisode de renouvellement faunique important qui débute dans la partie supérieure de la sous-zone àPs. picteti.

Keywords: Ammonoids; Upper Hauterivian; Zonation; Mediterranean Province

Mots clés : Ammonites ; Hauterivien supérieur ; Zonation ; Province Méditerranéenne

* Corresponding author.

E-mail address: mcompany@ugr.es (M. Company).

Geobios 36 (2003) 685–694

www.elsevier.com/locate/geobio

doi:10.1016/j.geobios.2002.12.001

1. Introduction

In the current standard zonation for the Mediterranean

region (Hoedemaeker and Rawson, 2000), the uppermost

Hauterivian interval is represented by the Crioceratites bale-

aris Zone and the Pseudothurmannia angulicostata auct.

Zone. These two units, introduced by Busnardo (1984) in his

zonation for the Lower Cretaceous of southeastern France,

were adopted by the Lower Cretaceous Cephalopod Team in

its ﬁrst zonal scale formulated at the Digne Workshop (Hoe-

demaeker and Bulot, 1990). The Ps. angulicostata auct.

Zone was later, at the proposal of Ph. Hoedemaeker during

the Mula Workshop (Hoedemaeker and Company, 1993),

divided into two subzones: a lower Ps. ohmi Subzone and an

upper Ps. catulloi. This disposition has been retained un-

changed in the zonations subsequently proposed by the

working group.

The excessive simplicity of this scheme contrasts with the

high resolution attained by some of the zonations recently

proposed for other Lower Cretaceous intervals (see Klein

and Hoedemaeker, 1999). To solve this deﬁciency, more

detailed analyses of the ammonite distribution in the upper-

most Hauterivian were needed in order to identify accurately

the sequence of bioevents and to enable the construction of a

more precise zonation for this interval. To this end, we

undertook bed-by-bed sampling of several sections located

in different palaeogeographic domains of the Betic Cordil-

lera (Fig. 1). These sections are:

•Barranco de la Aguzadera (La Guardia, Jaén): sections

X.G and X.G1.

•Ermita de Cuadros (Bedmar, Jaén): section X.EC.

•Río Argos (Caravaca, Murcia): sections X.Ag1 (= sec-

tion A in Hoedemaeker, 1995)(Fig. 2), X.Ag4 and

X.Ag5.

•Barranco de Cavila (Caravaca, Murcia): section X.Kv3.

•Arroyo de Gilico (Cehegín, Murcia): section X.V1

(Fig. 3).

•Cerro del Tornajo (Lorca, Murcia): sections X.Tj1 and

X.Tj2.

•Sierra del Cid (Petrer, Alicante): sections X.A1 and

X.A2.

•Barranco de la Querola (Cocentaina, Alicante): section

X.Q.

•Cantera de l’Almuxic (Oliva,Valencia): section X.O.

More than 5000 identiﬁable ammonites were collected

from the interval studied in these sections. The analysis of

species distribution has enabled us to divide the two classic

zones into several subzones (Fig. 4). Thus, we have recogn-

ised four subzones in the Cr. balearis Zone and three sub-

zones in the Ps. ohmi Zone (= Ps. angulicostata auct. Zone).

All of these are interval subzones, the lower boundary of

which is deﬁned by the ﬁrst occurrence of the index species,

the upper boundary coinciding with the base of the next unit.

Although the zonal scheme presented here is proposed only

for the Betic Cordillera, its constituent units can be easily

Fig. 1.Geographical and geological location of the studied sections.

Fig. 1. Localisation géographique et géologique des coupes étudiées.

686 M. Company et al. / Geobios 36 (2003) 685–694

Fig. 2.Río Argos-1 section (X.Ag1). Lithological succession and ammonite distribution.

Fig. 2. Coupe de Río Argos 1 (X.Ag1). Succession lithologique et distribution des ammonites.

687M. Company et al. / Geobios 36 (2003) 685–694

recognised in many other parts of the Mediterranean area. A

preview of these results was presented by Aguado et al.

(2001).

2. Zonation

2.1. Crioceratites balearis Zone

This unit was introduced, without formal deﬁnition, by

Busnardo (1984) and later deﬁned by Hoedemaeker and

Leereveld (1995) as the biostratigraphic interval between the

ﬁrst occurrence of Cr. balearis (NOLAN) and the ﬁrst occur-

rence of Ps. ohmi (WINKLER). Four subzones, deﬁned by

the consecutive appearances of four different chronospecies

belonging to the same Crioceratites lineage, can be recogn-

ised within this zone. These species are: Cr. balearis

(Fig. 5(1–3)), Cr. binelli (ASTIER) (Fig. 5(4)), Cr. krenkeli

(SARKAR) (Fig. 5(6–8)) and Cr. angulicostatus

(D’ORBIGNY) (Fig. 5(9–10)). They correspond to four suc-

cessive steps in what appears to be an evolutionary trend

Fig. 3.Arroyo Gilico section (X.V1). Lithological succession and ammonite distribution.

Fig. 3. Coupe de Arroyo Gilico (X.V1). Succession lithologique et distribution des ammonites.

688 M. Company et al. / Geobios 36 (2003) 685–694

towards a stronger ornamentation and a clearer differentia-

tion between main and intermediate ribs in the middle onto-

genetic stages. In addition to these forms, we have found

specimens attributable to Cr. majoricensis (NOLAN)

(Fig. 5(5)), which probably represent morphotypes of the

same lineage showing a more prolonged trituberculate stage

(trituberculate ribs can be present in the innermost whorls of

all members of the group).

Together with the genus Crioceratites, the faunal assem-

blage from this zone is composed mainly of long-ranging

species such as Plesiospitidiscus subdiffıcilis (KARAK-

ASCH) (Fig. 6(3)), Abrytusites neumayri (HAUG), Neolis-

soceras subgrasianum (DRUSHCHITS), Lytoceras subﬁm-

briatum (D’ORBIGNY), Phylloceras thetys (D’ORBI-

GNY), Phyllopachyceras infundibulum (D’ORBIGNY) and

Phyllopachyceras winkleri (UHLIG).

2.1.1. Cr. balearis Subzone

Cr. balearis is the ﬁrst member of the lineage. Its orna-

mentation in the middle stages consists of uniform and dense

ribs lacking distinct umbilical tubercles. The fauna in this

interval is scarce and shows low diversity. The last specimens

of Discoidellia couratieri VERMEULEN occur at the base

of this subzone, whereas the ﬁrst Paraspiticeras appear in its

upper part.

2.1.2. Cr. binelli Subzone

The next species of the group, Cr. binelli, differs from Cr.

balearis in the appearance of rib bundles rising from well-

deﬁned umbilical bullae. The faunal assemblages from this

subzone are still poorly diversiﬁed and numerically domi-

nated by the index species and Pl. ligatus.

2.1.3. Cr. krenkeli Subzone

Cr. krenkeli shows a clear differentiation between main

and intermediate ribs from quite early ontogenetic stages. In

this subzone, the fauna is more abundant and diversiﬁed than

in the previous ones. Discoidellia vermeuleni CECCA,

FARAONI and MARINI and the ﬁrst representatives of the

genus Anahamulina, attributable to An. jourdani (ASTIER

sensu OOSTER), appear together with the index species at

the base of this interval.

2.1.4. Cr. angulicostatus Subzone

As is well known (Sarkar, 1955; Hoedemaeker, 1995), the

species Ammonites angulicostatus D’ORBIGNY has been

Fig. 4.Proposed zonation and ranges of the most signiﬁcant ammonite species.

Fig. 4. Zonation proposée et distribution stratigraphique des principales espèces d’ammonites.

689M. Company et al. / Geobios 36 (2003) 685–694

690 M. Company et al. / Geobios 36 (2003) 685–694

misinterpreted by most authors. After having analysed a cast

of the holotype, we are convinced, in agreement with Hoede-

maeker (1995), that this taxon should be placed among the

Crioceratites species. Cr. angulicostatus would then be the

last member of the lineage that begins with Cr. balearis and

the ancestor of the forms currently included in the genus

Pseudothurmannia (see taxonomic note below).

The ﬁrst Emericiceras and Acrioceras, respectively repre-

sented by Em. thiollierei (ASTIER) and Ac. meriani

(OOSTER) (Fig. 5(11)), also appear in this subzone. These

two nominal species may be no more than the two antidimor-

phs of a single biological species.

This stratigraphic interval is very unevenly represented in

the sections studied (compare Figs. 2 and 3), probably be-

cause of the slumps, which frequently affect the sediments of

that age.

2.2. Pseudothurmannia ohmi Zone

We use this unit in the sense of Hoedemaeker and Leerev-

eld (1995), who introduced it as a substitute for the ancient

Ps. angulicostata Zone. According to their interpretation, the

Ps. ohmi Zone would correspond to the interval comprised

between the ﬁrst occurrence of the index species and the

lower boundary of the Barremian stage. This interval is

characterised by the development of the genus Pseudothur-

mannia. It can be divided into three subzones deﬁned by the

consecutive appearances of Ps. ohmi (WINKLER) (Fig. 6(1,

2)), Ps. mortilleti (PICTET and DE LORIOL) (Fig. 6(4)) and

Ps. picteti (SARKAR) (Fig. 6(6, 7)). These three species also

represent three successive stages of an evolutionary trend

towards a more involute coiling.

Together with the Pseudothurmannia species, which are

by far the main components, the faunal assemblages from

this zone are composed of heteromorphs, desmoceratids,

phylloceratids and other minor groups. Contrary to the data

presented by some authors (Vašícˇek, 1995; Hoedemaeker,

1995; Avram and Melinte, 1998), we have not found Crio-

ceratites of the balearis-binelli group coexisting with

Pseudothurmannia. In this respect, our observations coin-

cide with those of Vermeulen (1980), Braga et al. (1982),

Autran (1993) and Ropolo (1995). These discrepancies may

be due to differences in taxonomic interpretations.

2.2.1. Pseudothurmannia ohmi Subzone

The base of this subzone, as already deﬁned by Hoede-

maeker and Leereveld (1995), coincides with the ﬁrst occur-

rence of the index species. Ps. ohmi is the ﬁrst and more

evolute species of the genus Pseudothurmannia. It differs

from its ancestor, Cr. angulicostatus, in having the whorls

always in touch and having deﬁnitely lost the initial trituber-

culate stage. The fauna from this subzone is very abundant

and composed, in addition to the index species, of taxa

already present in lower levels.

2.2.2. Pseudothurmannia mortilleti Subzone

The lower boundary of this subzone is deﬁned by the ﬁrst

occurrence of Ps. mortilleti, here considered a senior syn-

onym of Ps. catulloi (PARONA). An important faunal re-

newal, already pointed out by Hoedemaeker (1995), takes

place around this boundary. Besides the index species, Ps.

pseudomalbosi(SARASIN and SCHÖNDELMAYER)(here

considered a senior synonym of Ps. sarasini SARKAR)

(Fig. 6(5)), Anahamulina subcylindrica (D’ORBIGNY)

(Fig. 6(9)), “Barremites” uhligi (HAUG sensu SARASIN

and SCHÖNDELMAYER), Discoidellia favrei (OOSTER)

and Lytoceras densiﬁmbriatum UHLIG also appear at this

level. At the same time, D. vermeuleni and other long-

ranging taxa such as Nl. subgrasianum, L. subﬁmbriatum

and Ph. winkleri disappear.

This faunal turnover coincides with the start of an organic-

rich interval that, because of its sedimentologic and palaeon-

tologic characteristics, can be considered the equivalent of

the Faraoni Level, recognised in a similar stratigraphic posi-

tion in central and northern Italy and southeastern France

(Cecca et al., 1994; Cecca et al., 1996; Baudin et al., 1999).

2.2.3. Pseudothurmannia picteti Subzone

The base of this subzone is deﬁned by the appearance of

Ps. picteti, the youngest and more involute species of the

genus Pseudothurmannia. Apart from the index species,

which is restricted to the lower part of the subzone, the fauna

from this interval is not well characterised. Small and hardly

interpretable heteromorphs are frequent, among which we

have identiﬁed Paraspinoceras morloti (OOSTER)

(Fig. 6(8)), a probable senior synonym of Par. evolutus

(FALLOT and TERMIER). The ﬁrst true Barremites, attrib-

Fig. 5.1. Crioceratites balearis (NOLAN), X.Ag1.131.7, Cr. balearis Subzone. 2. Crioceratites balearis (NOLAN), X.G.6.10, Cr. balearis Subzone. 3.

Crioceratites balearis (NOLAN), X.G.6.4, Cr. balearis Subzone. 4. Crioceratites binelli (ASTIER), X.EC.3.1, Cr. binelli Subzone. 5. Crioceratites

majoricensis (NOLAN), X.EC.4.1, Cr. binelli Subzone. 6. Crioceratites krenkeli (SARKAR), X.G1.2.1, Cr. krenkeli Subzone. 7. Crioceratites krenkeli

(SARKAR), X.G1.(5-7).1, Cr. krenkeli Subzone. 8. Crioceratites krenkeli (SARKAR), X.G1.6.1, Cr. krenkeli Subzone. 9. Crioceratites angulicostatus

(D’ORBIGNY), X.V1.-2.65, Cr. angulicostatus Subzone. 10. Crioceratites angulicostatus (D’ORBIGNY), X.V1.-4.15, Cr. angulicostatus Subzone. 11.

Acrioceras meriani (OOSTER), X.Ag1.145.30, Ps. ohmi Subzone. (All specimens natural size).

Fig. 5. 1. Crioceratites balearis (NOLAN), X.Ag1.131.7, Sous-Zone à Cr. balearis.2. Crioceratites balearis (NOLAN), X.G.6.10, Sous-Zone à Cr. balearis.

3. Crioceratites balearis (NOLAN), X.G.6.4, Sous-Zone à Cr. balearis.4. Crioceratites binelli (ASTIER), X.EC.3.1, Sous-Zone à Cr. binelli.5. Crioceratites

majoricensis (NOLAN), X.EC.4.1, Sous-Zone à Cr. binelli.6. Crioceratites krenkeli (SARKAR), X.G1.2.1, Sous-Zone à Cr. krenkeli. 7. Crioceratites krenkeli

(SARKAR), X.G1.(5-7).1, Sous-Zone à Cr. krenkeli.8. Crioceratites krenkeli (SARKAR), X.G1.6.1, Sous-Zone à Cr. krenkeli.9. Crioceratites angulicostatus

(D’ORBIGNY), X.V1.-2.65, Sous-Zone à Cr. angulicostatus.10. Crioceratites angulicostatus (D’ORBIGNY), X.V1.-4.15, Sous-Zone à Cr. angulicostatus.

11. Acrioceras meriani (OOSTER), X.Ag1.145.30, Sous-Zone à Ps. ohmi. (Tous les échantillons sont ﬁgurés en grandeur naturelle).

691M. Company et al. / Geobios 36 (2003) 685–694

692 M. Company et al. / Geobios 36 (2003) 685–694

utable to B. dimboviciorensis BRESKOVSKI, also appear in

this interval. The forms described by Cecca et al. (1998) as B.

primitivus,coming from the Faraoni Level,are interpreted by

us as a variety of Ps. subdiffıcilis.

2.3. Hauterivian/Barremian boundary

According to the current deﬁnition (Rawson, 1996), the

ﬁrst occurrence of Taveraidiscus hugii (OOSTER)

(Fig. 6(10)) marks the lower boundary of the Barremian

stage. This event forms a part of a major faunal renewal that

begins in the upper part of the Ps. picteti Subzone. Other

species such as T. intermedius (D’ORBIGNY) (Fig. 6(11))–

here considered a senior synonym of T. vandeckii (OOSTER)

and T. kiliani (PAQUIER) – “Barremites” boutini

(MATHERON), Silesites sp., Psilotissotia mazuca (CO-

QUAND), Arnaudiella malladae (NICKLÈS) and Hamulin-

ites munieri (NICKLÈS) also appear around this level.

Hoedemaeker (1995) argued that the Haute

rivian/Barremianboundary should be drawn at the base of his

Ps. catulloi Subzone, equivalent to the base of our Ps. mor-

tilleti Subzone. This author considered this level to separate

an assemblage of reputedly Hauterivian ammonites from an

assemblage composed mostly of Barremian species. Never-

theless, some of the taxa, which, according to Hoedemaeker,

would appear in the Ps. catulloi Subzone, are actually

present in lower levels.This is the case of Ab. neumayri and

the genera Paraspiticeras, Emericiceras and Acrioceras.

Moreover, Ps. subdiffıcilis is still present throughout the Ps.

mortilleti Subzone, being substituted by B. dimboviciorensis

in the Ps. picteti Subzone. It is also worth mentioning that the

assemblages from the Ps. mortilleti Subzone are composed

for the most part of specimens of Pseudothurmannia (63% of

the whole) and Plesiospitidiscus and other long-ranging taxa

inherited from lower levels (12%), giving these assemblages

a marked Hauterivian look.

3. Taxonomic note

On establishing the genus Pseudothurmannia,Spath

(1923) designated Am. angulicostatus D’ORBIGNY (in Pic-

tet, 1863: Pl. 1bis, Fig. 1) as “genotype”. Sarkar (1955)

however, showed that Pictet’s specimen could not be conspe-

ciﬁc with Am. angulicostatus D’ORBIGNY and separated it

as a new species Ps. picteti SARKAR. Moreover, as shown

above, the species of d’Orbigny is closer to Crioceratites

species than to the forms currently included in the genus

Pseudothurmannia. We believe that Article 70.3 of the

I.C.Z.N. is applicable to this case. According to it, and in

order to maintain the usage, we designate Ps. picteti

SARKAR as type species of the genus Pseudothurmannia.

Acknowledgements

We are very grateful to our colleagues Ph. Hoedemaeker

(Nationaal Natuurhistorisch Museum, Leiden), G. Schairer

(BayerischeStaatssammlung für Paläontologie, Munich)and

D. Decrouez (Muséum d’histoire naturelle, Geneva) for hav-

ing provided us with casts of the holotypes of Cr. angulicos-

tatus, Ps. ohmi and Ps. picteti. Critical comments of F.

Atrops and P.F. Rawson are also gratefully appreciated. This

work has been co-ﬁnanced by Project BTE 2001-3020

(Spanish Ministry of Science and Technology) and Research

Group RNM-178 (Junta de Andalucía).

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Fig. 6.1. Pseudothurmannia ohmi (WINKLER), X.Ag5.19.r, Ps. ohmi Subzone. 2. Pseudothurmannia ohmi (WINKLER), X.Ag1.144.39, Ps. ohmi Subzone.

3. Plesiospitidiscus subdiffıcilis (KARAKASCH), X.V1.-11.63, Cr. krenkeli Subzone. 4. Pseudothurmannia mortilleti (PICTET and DE LORIOL), X.V1.6.2,

Ps. mortilleti Subzone. 5. Pseudothurmannia pseudomalbosi (SARASIN and SCHÖNDELMAYER), X.V1.3a.16, Ps. mortilleti Subzone. 6. Pseudothurman-

nia picteti SARKAR., X.V1.10.1, Ps. picteti Subzone. 7. Pseudothurmannia picteti SARKAR., X.G1.20.1, Ps. picteti Subzone. 8.Paraspinoceras morloti

(OOSTER), X.V1.13.28, Ps. picteti Subzone. 9. Anahamulina subcylindrica (D’ORBIGNY), X.V1.30.1, T. hugii Zone. 10. Taveraidiscus hugii (OOSTER),

X.Ag4.28.104, T. hugii Zone. 11. Taveraidiscus intermedius (D’ORBIGNY), X.Ag4.37.28, T. hugii Zone. (All specimens natural size).

Fig. 6. 1. Pseudothurmannia ohmi (WINKLER), X.Ag5.19.r, Sous-Zone à Ps. ohmi.2. Pseudothurmannia ohmi (WINKLER), X.Ag1.144.39, Sous-Zone à Ps.

ohmi.3. Plesiospitidiscus subdiffıcilis (KARAKASCH), X.V1.-11.63, Sous-Zone à Cr. krenkeli.4. Pseudothurmannia mortilleti (PICTET and DE LORIOL),

X.V1.6.2, Sous-Zone à Ps. mortilleti.5. Pseudothurmannia pseudomalbosi (SARASIN and SCHÖNDELMAYER), X.V1.3a.16, Sous-Zone à Ps. mortilleti.6.

Pseudothurmannia picteti SARKAR., X.V1.10.1, Sous-Zone à Ps. picteti.7.Pseudothurmannia picteti SARKAR., X.G1.20.1, Sous-Zone à Ps. picteti.8.

Paraspinoceras morloti (OOSTER), X.V1.13.28, Sous-Zone à Ps. picteti.9. Anahamulina subcylindrica (D’ORBIGNY), X.V1.30.1, Zone à T. hugii.10.

Taveraidiscus hugii (OOSTER), X.Ag4.28.104, Zone à T. hugii.11. Taveraidiscus intermedius (D’ORBIGNY), X.Ag4.37.28, Zone à T. hugii. (Tous les

échantillons sont ﬁgurés en grandeur naturelle).

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Synchrony of carbon cycle fluctuations, volcanism and orbital forcing during the Early Cretaceous

Article

Feb 2023
EARTH-SCI REV

Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions

Article

Nov 2020
GLOBAL PLANET CHANGE

The ages and durations of the stages in the Early Cretaceous commonly show discrepancies of several million years when the Geologic Time Scale (2020) from the International Commission of Stratigraphy (ICS) and recently published radio-astrochronologic data are compared. Here, we provide an astronomical time scale for the Barremian Stage and its subdivisions based on spectral analyses performed on magnetic susceptibility and calcium carbonate content series in two sections studied located in the Subbetic Domain of southeastern Spain. The sections are tied to Tethyan ammonite and calcareous nannofossil zones, allowing detailed correlations with other sections in the Subbetic Domain and other basins in the Tethyan Realm. Eccentricity cycles are observed throughout the series and can be correlated with the eccentricity cycles observed in other sections in the Subbetic Domain, showing that the results are reproducible. Based on the number of 405-kyr eccentricity cycles in the study interval, and considering uncertainties linked to variations in the sedimentation rates within an eccentricity cycle, the duration of the Barremian Stage is calculated at 4.58 -0.29 +0.15 Myr. From the astronomical time scale proposed here, together with recently published radio-astrochronological studies, the base of the Barremian Stage is dated at 125.98 ± 0.21 Ma and the top at 121.40 ± 0.34 Ma. The age of the Barremian/Aptian boundary differs from the ICS Geologic Time Scale 2020 by 3.6 Myr, but fits with the age of the base of magnetochron M0r recently deduced from a synthesis of radiochronologic data. The episodes of environmental change of the late Hauterivian–Barremian show an average pacing of 2.2 Myr, suggesting an orbital control on the expansion of oceanic anoxic conditions in the Tethys.

Stratigraphically significant, sporadic Early Cretaceous ammonites in Butkov Quarry (Central Western Carpathians, Slovakia)

Article

Sep 2023

Zdeněk Vašíček

Butkov Quarry provides the best exposed stratigraphic sequence of marly limestones with Early Cretaceous ammonites in the Manín Nappe of the Central Western Carpathians. The presented paper deals with the sporadically occurring zonal ammonites, or ammonites of guiding character, from the Lower Valanginian to Upper Hauterivian. Sixteen species are taxonomically elaborated here in detail. More attention is given to the basic taxonomy of the Subfamily Crioceratitinae Gill, 1871. The species described here, like most of the previously published species from Butkov Quarry, are representatives of the Mediterranean bioprovince and are close to the ammonite association from the Vocontian Basin.

Lower Cretaceous ammonoids from the Neuquén Basin, Argentina: The late Hauterivian Paraspiticeras and associated faunas

Article

May 2023
CRETACEOUS RES

The Paraspiticeras groeberi Zone is one of the five ammonoid biozones previously recognized in the Agua de la Mula Member of the Agrio Formation of late Hauterivian age in the Neuquén Basin of west-central Argentina. However, the ammonoid faunas of this zone and the beds immediately below, corresponding to the upper levels of the current Crioceratites diamantensis Zone, remain poorly known. Extensive collections now allow us to recognize a diverse endemic ammonoid fauna. After an exhaustive taxonomic and stratigraphic review, the Paraemericiceras argentinense and Paraspiticeras bituberculatum Zones are proposed to replace the P. groeberi Zone and the original index species is now placed in Vutacuracrioceras gen. nov. Vutacuracrioceras groeberi first appears with the earliest Paraemericiceras argentinense gen. et sp. nov. and extends through both zones. It is joined in the Paraspiticeras bituberculatum Zone by the index species and Paraspiticeras sp. aff. P. precrassispinum, Australopseudothurmannia flexuosa gen. et sp. nov. and Hamulinites sp. Based on this new biostratigraphic scheme, the late Hauterivian in the Neuquén Basin is represented now by six ammonoids zones that can be correlated provisionally with the European standard of the West Mediterranean Province of the Tethyan Realm

Updated geochemical insights on the Weissert and Faraoni events in the southern Tethyan margin (northern Tunisia)

Article

Full-text available

Nov 2021

Within the Valanginian–Hauterivian series of the northern Tethyan margin, two organic-rich laminated black shale intervals corresponding to the Valanginian Weissert and the late Hauterivian Faraoni oceanic anoxic events (W-OAE and F-OAE, respectively) are well documented. However, in Tunisia as part of the southern Tethyan margin, despite several biostratigraphic and structural studies awarded to this period, geochemical characterization based mainly on wireline logs data was undertaken. Here, we aimed to confirm the extension of these Valanginian–Hauterivian organic-rich deposits throughout a bulk and biomolecular geochemical (Rock–Eval pyrolysis and gas chromatography–mass spectrometry analysis) study carried out on selected surface outcrops in northern Tunisia. To that end, three hemi-pelagic sections belonging to the Tunisian backbone (Jebel Zaghouan), the Tunisian trough (Jebel Oust) and the diapiric zone (Jebel Boulahouajeb) have been chosen and analysed with highly interest to their organic matter (OM) contents and biomolecular composition. Rock–Eval pyrolysis shows that Jebel Oust section presents total organic carbon (TOC) contents ranging from 0.18 to 0.57 wt% with an average of 0.38 wt% and low hydrogen index (HI) values ranging from 15 to 74 mg HC/g TOC indicating a type IV OM. Its hydrocarbon generation potential (HGP) is very low where the average value is around 0.19 mg HC/g rock, while Jebel Zaghouan section reveals TOC values reaching up to 0.56 wt% with a low HGP up to 1.01 mg HC/g rock and high maturity levels attested by Tmax values ranging from 449 to 460 °C. Jebel Boulahouajeb section shows low TOC values ranging from 0.22 to 0.69 wt% with an average of 0.35 wt%. Its HGP is very low with a maximum value of 1.67 mg HC/g rock and presents marginally mature to mature stage where Tmax values ranging from 438 to 450 °C with an average of 443 °C. This maturity distribution was guided by the basin architecture marked by the presence of subsiding zones in local faulted blocks and palaeohighs occupied by Triassic salt domes and horsts. Molecular biomarker analyses from the Valanginian–Hauterivian Boulahouajeb and Jebel Zaghouan facies indicated a mainly marine origin of the OM and a suboxic depositional environment in a normal marine water column. Throughout this study, we confirm the installation, in the southern Tethyan margin (northern Tunisia), of dysoxic depositional conditions during the early Valanginian and late Hauterivian times corresponding to the Weissert and Faraoni events, respectively. However, these depositional environments were not favourable for preservation of high quantities of OM. This was mainly controlled by the presence of an oxygen minimum zone generally disturbed by detrital discharges. Additionally, the results highlight the important interplay of the basin architecture, the various faults developed with an extensional tectonic regime during the Valanginian–Hauterivian period, the warm climate conditions and the eustatic sea-level variations where transgressive systems tracts coincide with black shales deposited majorly under dysoxic conditions.

Upper Mesozoic stratigraphy of Sikhote-Alin (Russian Far East) and (northeastern China: non-marine and marine correlations. Part 1: Upper Jurassic – Hauterivian

Article

Mar 2021

Upper Mesozoic (Upper Jurassic and Cretaceous) rocks are widely distributed in Sikhote-Alin (Russian Far East) and northeastern China. In Sikhote-Alin, the Upper Jurassic and Lower Cretaceous rocks are represented mainly by marine deposits, whereas the Upper Cretaceous rocks are mainly volcanic and non-marine sedimentary-volcanic. In northeastern China, the upper Mesozoic rocks are, on the contrary, mainly non-marine. Fully marine Upper Jurassic – Valanginian deposits are restricted to the northeastern Heilongjiang Province near the border with Russia. Barremian-Albian non-marine deposits alternating with marine ones also occur in this region. They contain marine and non-marine fauna and, therefore, represent an important object for non-marine and marine correlation. On the rest of the territory of northeastern China, upper Mesozoic rocks are represented by non-marine sedimentary and volcanogenic deposits. The complex geological structure of the region as well as different types of sedimentary basins cause difficulties in correlation between the upper Mesozoic rocks of Sikhote-Alin and northeastern China. Despite the long history of investigations, their correlation schemes are still rare. Creation of a correlation scheme between Sikhote-Alin and northeastern China should be based on revision of published stratigraphic data on both regions. This article is the first in a series of articles devoted to the upper Mesozoic stratigraphy of Sikhote-Alin and northeastern China. In the present article the Upper Jurassic – Hauterivian stratigraphy of Sikhote-Alin and northeastern China is reviewed. The Upper Jurassic – Hauterivian deposits of Sikhote-Alin and northeastern China contain abundant Buchia and rarer ammonites. Based on stratigraphic distribution of buchiid assemblages, the correlation scheme for Kimmeridgian – Valanginian (possibly lowermost Hauterivian) strata of northeastern China and Sikhote-Alin is proposed. The succession of Jurassic-Cretaceous buchiid assemblages of Sikhote-Alin and northeastern China is similar to those of the other regions, e.g., Northern Siberia (Arctic Realm) and California (North Pacific Realm).

Report on the 7th International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the Kilian Group (Warsaw, Poland, 21st August 2022): State of the art on the current Standard Ammonite Zonation of the Western Tethyan Mediterranean Province

Article

Full-text available

Sep 2023
CRETACEOUS RES

The 7th meeting of the IUGS Lower Cretaceous Ammonite Working Group the ‘Kilian Group (KG)’ was held in Warsaw, Poland, in 21st August 2022. Need of major changes for the Jurassic/Cretaceous transition, namely to the uppermost Tithonian and lower Berriasian, and for the upper Aptian and Albian schemes is a long–known issue, which are finally conceptualized and hereby introduced into the Standard Mediterranean Ammonite Zonation (SMAZ, Western Tethys). Besides, refinements were added to the Valanginian and Hauterivian stages, discussion on some zonal indices and units are also provided. The KG highlights again the exclusive use of interval zones and subzones. Most important changes of the uppermost Tithonian–Berriasian stages are the followings: i) use of two folded Berriasian is agreed, to be in better accordance with ammonite turnovers and microfossil framework; ii) uppermost Tithonian Lopeziceras chaperi, top–uppermost Tithonian to lowermost Berriasian Praedalmasiceras progenitor and lower Berriasian Pseudosubplanites grandis Zones are accepted to be introduced into the SMAZ, these three zones to cover the former ‘Berriasella’ jacobi Zone auctorum which is formally abandoned; iii) lower Berriasian Delphinella delphinensis Subzone is accepted as a reliable marker level of the upper Praedalmasiceras progenitor Zone; iv) Strambergella jacobi Zone is established and discussed. Tirnovella occitanica Zone and Tirnovella subalpina Subzone are discussed. Modifications on the Valanginian zonation are the followings: i) Neocomites premolicus Subzone is re–defined, ii) Neolissoceras (Vergoliceras) salinarium Subzone is introduced; iii) Neocomites neocomiensiformis Zone is divided into two subzones, the lower N. neocomiensiformis and the upper Busnardoites campylotoxus Subzones. Modifications on the Hauterivian stage are the followings: i) all horizons are deleted; ii) Olcostephanus (Olcostephanus) variegatus Subzone is introduced; iii) Balearites angulicostatus Subzone is introduced; iv) all subzonal index–species of the B. balearis Zone are assigned to genus Balearites; v) Pseudothurmannia mortilleti is considered as a senior synonym of P. catulloi, therefore its nominal subzone also changed its name to mortilleti. No change in the Barremian scheme, however the base of Toxancyloceras vandenheckii Subzone and Zone is defined by the first appearance of the genus Toxancyloceras. Most important changes of the upper Aptian zonation are the followings: i) Nolaniceras nolani and Hypacanthoplites jacobi zones are retained from the SMAZ; ii) re–introduction of Diadochoceras nodosocostatum Zone is given. For the Aptian–Albian transition interval, introduction of ‘Hypacanthoplites’ elegans Zone is accepted, where the Aptian/Albian boundary lies within. Most important zonal changes of the Albian stage are: i) the Leymeriella−based succession is abandoned from the SMAZ and replaced by the cosmopolitan Douvilleiceras−based succession; ii) Douvilleiceras leightonense Zone is introduced; iii) middle Albian Hoplites dentatus, Euhoplites loricatus, Euhoplites lautus zones and Hoplites spathi Subzone are retained from the SMAZ and restricted to the Boreal ammonite scheme; iv) Lyelliceras lyelli Subzone arisen to zonal rank defining the basal middle Albian; v) Oxytropidoceras (Oxytropidoceras) roissyanum Zone is introduced; vi) upper Albian zonation based on the phyletic lineage of Mortoniceratids is kept, however generic names of the indices are modified to Pervinquieria; vii) Pervinquieria pricei Zone is divided into three subzones of Hysteroceras varicosum, H. binum and H. choffati from the oldest to youngest; viii) Pervinquieria inflata Zone is divided into two subzones of Hysteroceras bucklandi and Cantabrigites spp. The KG tributes to our recently deceased ammonitologist colleagues in the Supplement, a discussion on the future work is provided. The next Kilian Group meeting will be held in Hannover, prior to the first day of the 12th International Symposium on the Cretaceous System.

New insights into the Barremian–lower Aptian calcareous nannofossils of the Mediterranean Tethys: Chronostratigraphic and paleobiogeographic implications

Article

Full-text available

Mar 2022
Mar Micropaleontol

A detailed study of calcareous nannofossil assemblages from twelve uppermost lower Barremian–lower Aptian sections in the Subbetic domain of the Betic Cordillera was performed. Seven new nannofossil species (Crucibiscutum bastetanum, Crucibiscutum gracile, Chiastozygus lamprostauros, Cyclagelosphaera platyaspis, Lithraphidites aichmoides, Lithraphidites pugio, and Rhagodiscus sicutclipeus) are described, one species is emended (Lithraphidites magnus) and the taxonomic concept of the marker species Hayesites irregularis is discussed and clarified. The detailed stratigraphic ranges of the new species, together with those of other relevant taxa, are determined and correlated to standard ammonite biostratigraphy. Age estimates of biostratigraphically relevant calcareous nannofossil biohorizons are calculated using astrochronologically tuned cyclostratigraphic data. Five new calcareous nannofossil subzones are proposed which enhance upper Barremian biostratigraphic resolution at a regional scale and are directly correlated with respect to the standard Tethyan ammonite zonation. Two of the new species described here are used as biostratigraphic markers for the newly proposed subzones. The duration of each subzone is provided through astrochronological calibration. This study allows the refinement of the calcareous nannofossil zonation for the Mediterranean–Atlantic province of the Tethyan domain. The implications of these new results are discussed regarding the extant definition and use of the Barremian/Aptian boundary. The morpho-evolutionary trends of selected nannofossil groups are reviewed in relation to the latest Barremian–Aptian paleogeographic changes, showing these were a prominent factor controlling calcareous nannoplankton evolution and biogeographical distribution in the west European-Atlantic region.

Upper Hauterivian nautiloids and associated invertebrate assemblage from the Barranco de la Muela section (southeastern Spain): Systematic, biostratigraphic and palaeoenvironmental implications

Article

Sep 2021
CRETACEOUS RES

The lower part of the Lower Cretaceous Bolos Sandstone Formation as exposed in the Barranco de la Muela section (Sierra de la Muela Range, southeastern Spain) yields two species of ornamented nautiloids, Cymatoceras neocomiense and Eucymatoceras plicatum. These have been collected together with other cephalopods (ammonoids, belemnites) and different invertebrates (corals, brachiopods, bivalves, gastropods, echinoids). This fossil assemblage includes numerous large macroconchs of the ammonite Pseudothurmannia mortilleti, here considered as a senior synonym of P. catulloi, index species of the homonymous subzone of the upper Hauterivian “Pseudothurmannia ohmi” Zone. On this basis, the here reported findings constitute the first biostratigraphically well-constrained records of C. neocomiense and E. plicatum, namely in the Pseudothurmannia catulloi Subzone. The presence of these two ornamented and relatively depressed nautiloids in fine sandstone levels interbedded with sandy marls of the Bolos Formation, together with the palaeoecological characteristics of the associated fauna suggest a nearshore to inner-middle shelf, shallow to moderately deep palaeoenvironment with mixed siliciclastic-carbonate sedimentation, and high to moderate energy.

Implications of the ‘hemihoplitid-like’ ammonites iterative morphology in the context of the late Tethyan Barremian (Early Cretaceous)

Article

Sep 2019

Hemihoplitidae evolution is well documented in the north-west Tethyan margin at the lower upper Barremian. In this context, the genus Lenicostites gen. nov. (L. rusticus), with ‘hemihoplitid-like’ morphology, is unexpected because of its age older than the earliest Hemihoplites and its evolutionary stasis that contrasts with the rapid changes of the Hemihoplitidae. Data show no connection between Hemihoplitidae and Lenicostitidae fam. nov. and the resemblance is homeomorphy. The numerous reported occurrences of Hemihoplitinae over the world are reviewed. Their critical revision shows that some of them are contradictory with the evolutionary history of the group. The ‘hemihoplitid-like’ morphology is iterative in several taxa without any phyletic links (homeomorphy). Reasons could be linked to the morphospace occupation in the zone of maximum equilibrium between different constraints (a Pareto-optimal solution), making such morphology effortless to reproduce. The Austral Homeomorphitinae subfam. nov. (with Homeomorphites aguirreurretae gen. nov. et sp. nov.) are assigned to the Neocomitidae. A phyletic link between Shasticrioceras and Antarcticoceras is suggested (Shasticrioceratidae fam. nov.). Until proven otherwise, there is no Hemihoplitinae outside the north and west margins of the Tethys (including the Essaouira Basin). Homeomorphy between Hemihoplitinae and Lenicostitidae fam. nov. is explored and convergence seems the most convincing hypothesis. The further appearance of Camereiceras (Hemihoplitinae) could establish favorable conditions for interspecific competition, and the disappearance of Lenicostites gen. nov. could be interpreted as a complete competitive replacement. In this hypothesis Lenicostites gen. nov. is a victim of the Gause Principle as it lost the Red Queen race.

Preliminary Ammonite zonation for the Lower Cretaceous of the Mediterranean region

Article

Full-text available

Jan 1990

The Barremian stage

Article

Full-text available

Jan 1996

Inter-regional correlation in the Barremian is impossible because of strong biotic differentiation between realms coupled with a lack of obvious non-biostratigraphic markers to provide good boundaries. Thus we have chosen the best of the limited options available to define boundaries within the Tethyan Realm. We recommend that the base of the Barremian be placed at the base of the Spitidiscus hugii ammonite Zone in the Rio Argos section, SE Spain. Supplementary information will be compiled to fully document this choice before formal submission via the Cretaceous Subcommission to the Commission on Stratigraphy. The base of the Upper Barremian should be defined by the first appearance of the ammonite Ancyloceras vandenheckei in one of the Subbetic sections in SE Spain, probably section X.KV (Barrano de Cavila, Caravaca). Other sections in the region require further documentation before the final recommendation can be made.

Ammonite zonation for the lower Cretaceous of the Mediterranean region, basis for the stratigraphic correlation within IGCP Project 262

Article

Full-text available

Jun 1993
Rev Esp Palaontol

This report is the synthesis of the discussions held during the 2nd W orkshop of the Lower Cretaceous Cephalopod Team of IGCP-Project 262: Tethyan Cretaceous Correlation (Mula, SE Spain, July 2-5, 1992). It presents a new proposition of zonal scheme fór the Lower Cretaceous of the M editerranean Region and justifications about the choice of the index-species fór somé biostratigraphical units. RESUMEN Se presentan las conclusiones dél " 2nd W orkshop of the Lower Cretaceous Cephalopod Team of IGCP-Project 262: Tethyan Cretaceous Correlation " , celebrado en M ula (SE de Espana) durante los días 2 al 5 de julio de 1992. Se incluye la propuesta de un nuevo esquem a zonal basado en am m onites para el Cretácico Inferior dél ámbito mediterráneo, así como notas aclaratorias sobre la elección de las especies índice de algunas unidades bioestratigráficas.

The Hauterivian-Barremian stage boundary in Svinita area (Banat, SW Romania)

Article