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Developments with fixing a Tithonian/Berriasian (J/K) boundary

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William A.P. Wimbledon at University of Bristol
William A.P. Wimbledon
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VOLUMINA JURASSICA, 2017, XV: 181–186
DOI: 10.5604/01.3001.0010.7467
Developments with fixing a Tithonian/Berriasian (J/K) boundary
William A.P. WIMBLEDON1
Chairman, Berriasian Working Group (ISCS)
At the Vienna Cretaceous Symposium (August 2017), the Berriasian Working Group (International Subcommission on
Cretaceous Stratigraphy) gave an account of its concerted research activities since 2009 (Wimbledon et al., 2017) – that and
this text are abbreviated summaries of Tithonian–Berriasian studies carried out in preparation for the consideration and
choice of a GSSP. Past decisions have consistently stated that such a GSSP should be dened in Tethys. Of Panthalassa, only
a comparatively small area of Lower Cretaceous ocean oor survives (NW Pacic), and subduction effected similar losses in
the Arctic, and thus parts of tropical-subtropical Tethys constitute the largest geographical entity remaining from J/K times,
and the one with the richest, most widespread and most studied biota.
In the 1970s to 1990s, discussions in various working groups about a J/K boundary made no substantive progress
(Remane, 1991), and were suspended until more auspicious times came. By the early 2000s, J/K correlation had already
shifted away from a concentration on often endemic ammonites, which had repeatedly been recognised as a major obstacle
to correlation, even in western Tethys. In 2007, a new Berriasian Working Group (ISCS) was mooted and it initiated a new
phase of activity, concentrating on realities and rening Tithonian–Berriasian correlations, partly directed at xing a J/K
boundary. For this reason, the preoccupations of the earlier Cretaceous symposia and earlier working groups, dominated by
ammonite discussion, have been put aside and since 2009 work has refocussed on integrated high-resolution studies, includ-
ing ammonites, but more on the effective use of several microfossil groups (e.g. calpionellids, calcareous nannofossils, cal-
careous dinoagellates), which give greater precision, calibrated with magnetostratigraphy. The J/K interval is without any
marked chemostratigraphic event that can help us in xing a boundary, isotopic excursions are lacking (Price et al., 2016),
and thus correlative methods must be predominantly biostratigraphic and magnetostratigraphic. The WG has focussed on the
detailed documentation of numerous key proles, old and new, putative J/K levels, calibrating magnetostratigraphy with fos-
sil range data, and examining prospective primary marker levels formerly suggested: e.g. the bases of the Jacobi Subzone, the
calpionellid Alpina Subzone, of M18r, and the Grandis Subzone. Many localities, from California to Tibet and the Russian
Far East, have been documented and assessed, including classical localities in France, Crimea, etc. Of course, long-range
correlations to some remote boreal regions, with impoverished, endemic biotas (vis a vis Tethys), as well as the extensive
non-marine basins, remain approximate. Though much work has recently been put into the magnetostratigraphy of the Pur-
beck Formation in England.
Documentation of classical Berriasian areas has led to some signicant revisions: we have highlighted the absence
of ‘Berriasella’ jacobi in the lower part of the nominal Jacobi Subzone (Frau et al., 2016), and the predominance of Delphi-
nella (e.g. France and Ukraine): thus Strambergella jacobi (and the Jacobi Subzone) has been ruled out as a GSSP marker.
Continuing problems with separating the ammonite assemblages of the Jacobi and Grandis subzones of past authors have
meant that we have not pursued the Grandis Subzone’s base as a putative stage base (Fig. 1). Better resolution also has shown
that the base of the Alpina (calpionellid) Subzone and the Jacobi (ammonite) Subzone do not coincide, and the Elliptica Sub-
zone base is below that of the Occitanica Zone.
1 School of Earth Sciences, University of Bristol, U.K.; mishenka1@yahoo.co.uk.
182 William A.P. Wimbledon
Another boundary alternative put forward in the past, the base of magnetozone M18r, has not proved to be effective as
a J/K marker. It is widely identied, of course, but it cannot be calibrated with any widespread fossil marker: its proposal
(e.g. Arkadi’ev et al., 2017) has not been supported by any documentation of biotic events (calpionellid, ammonite or nan-
nofossil) at, or bracketing the base of M18r.
For the last twenty years, building on a considerable and growing body of literature. calpionellids have been seen by nu-
merous authors as the most useful fossil group that could provide a J/K marker. Further, the turnover from Crassicollaria and
large Calpionella to small orbicular Calpionella alpina (together with Crassicollaria parvula and Tintinopsella carpathica)
has been documented repeatedly as the most consistent and widespread marker in the middle of magnetic subzone M19n.2n,
as recognised by the clear consensus amongst specialists at the Warsaw J/K workshop (Wimbledon, 2013). Work then in
progress has since come to fruition and the Alpina level has been proven further east in Tethys, to Arabia and Iran, and west
into the Americas (North and South). In June 2016, a formal ballot of the Berriasian WG led to a decisive vote that selected
the Alpina Subzone base as the primary T/B boundary marker.
The FADs of calcareous nannofossil species are helpful indicators of the base of Alpina Subzone, as they bracket this
level. But their ranges have been modied signicantly due to recent research (Fig. 2), undermining the 1980s biozonation of
Bralower. However, records of the FAD of Hexalithus strictus [=H. geometricus] have a restricted vertical distribution, strad-
dling the base of the Alpina Subzone in 19n.2n. The FAD of Nannoconus steinmannii minor occurs in mid M19n.2n: imme-
diately above the Alpina Subzone base (Puerto Escaño) or just below it (Rio Argos). Cruciellipsis cuvillieri, N. wintereri and
N. globulus globulus occur a little lower, though at Puerto Escaño the FAD of the rst species, unusually, is low in M19n.2n.
The FAD of N. wintereri occurs just below the Alpina Subzone’s base (e.g. Le Chouet, Puerto Escaño). Nannoconus kampt-
neri minor has latterly been recorded as rst appearing in the upper half of M19n, e.g. at Theodosia, Puerto Escaño and Le
nodiger singularis rjasanensis
M17r
anguiformis
?
Jacobi Grandis
Western Tethys
M18r
M19r
prim.preplic. lamplughi runctoni kochi
Purbeck Limestone Formation
?
okensis taimyrensis chetae sibiricus kochi
Tithonian Berriasian
Colomi Alpina Ferasini
Elliptica
Crassicollaria Calpionella
α
β
Published (1965) colloquiumdecision on J/K boundary
Published (1975) colloquiumdecision on J/K boundary
β
α
Micr.
Sea
Substeueroceras
koeneni
damesi
?
?
?
M17r
M18r
M19r
?
?
Praetintinnop.
Chitinoidella
Interm.
Remanei
Andreaei
Occitanica Boiss.
napaensis tehamaensis knoxville.
Nordvik
Russian
Platform
?
fulgens subditus
M19n.2n M19n.2n
M18n M18n
N. steinmannii minor
N. kamptneri minor
N. wintereri
R. asper
M16r M16r
Cinder
Bed
Mammal
Bed
Corongoceras
alternans
*
?
?
?
Euxinus
N. steinmannii steinmannii
N. kamptneri minor
N. erbae
N. wintereri, H. strictus,
C. cuvillieri, N. globulus globulus
N. globulus minor
N. puer
L. carniolensis
C. octofenestratus
C. surirellus, R. asper
N. kamptneri kamptneri
Arroyo Las
Loncoche Loicas
W. i.
Argenticeras
noduliferum
S. koeneni
?
?
Spiticeras
damesi
Cr.
Ch.
A.n.
M20n.2nM20n.2n
N. steinmannii minor
North Dorset
Simplex
Calpio-
nellopsis
Spiticeras
Ch.
A.n.
Chitinoidella
Cr. Crassicollaria
Argentiniceras noduliferum Zone
W.i. Windhauseniceras internispinosum
Fig. 1. Correlations of Tethys with austral and boreal regions
183Developments with xing a Tithonian/Berriasian (J/K) boundary
Chouet. Even more striking, N. kamptneri kamptneri and N. steinmannii steinmannii, previously used as infallible biozonal
indicators in M17r, have been found widely in lower M18r and the upper half of M19n (Figs. 1, 2)
In recent times, the western Tethyan core area with denite and precise microfossil correlations has been considerably
expanded. In particular, there have been nds of Lower Berriasian nannofossil markers in N. Africa, Ukraine, Yemen, Iraq,
Tibet and the Andes, C. alpina records in the Middle East and the Andes, the unambiguous application of the “western
Tethyan” calpionellid scheme to Mexico (Lopez Martinez et al., 2013), Arabia (Celestino et al., 2016), northern Iraq (Wim-
bledon et al., 2016) and Iran (Benzaggagh et al., 2012), and magnetostratigraphic studies extended to California, the Andes
and N. Africa for the rst time. Denite calpionellid records in Australia, Papua and New Guinea etc. await fuller investiga-
tion, as do problematic nannofossils and radiometric dates (Liu et al., 2013) in southern Tibet.
Interesting recent unpublished results from Fiume Bosso and Puerto Escaño reveal the calpionellid Ferasini Subzone has
its base in M19n.2n, with, consequently, a more thinly developed Alpina Subzone. Which perhaps raises questions about the
accuracy of earlier results for the Ferasini Subzone at these and other sites, and discrimination between M19n.1r and M18r
in previous accounts.
Failed attempts at identifying calpionellids in the Andean sequences were related by Remane, but critical rst nds by
Fernandez Carmona and Riccardi (1998, 1999) have given impetus to a breakthrough, with identication of the Chitinoidella
Zone (Kietzmann et al., 2011) and the Crassicollaria Zone in the Corongoceras alternans biozone (Kietzmann, 2017).
Though putative nannofossil proxies for the base of the Alpina Subzone (thus circa mid M19n) were recorded at Las Loicas
(Vennari et al., 2014), close to the base of the Argentiniceras noduliferum Zone, no Calpionella was found. Palaeomagnetic
Nannoconus wintereri
Cruciellipsis cuvillieri
N. steinmannii minor
Cretarhabdus octofenestratus
N. kamptneri minor
N. steinmannii steinmannii
N. kamptneri kamptneri
Nannoconus globulus globulus
Cretarhabdus surirellus
Hexalithus strictus =H. geometricus[ ]
Rhagodisus asper
Nannoconus erbae
Nannoconus globulus minor
Umbria granulosa granulosa
Nannoconus puer
Umbria granulosa minor
N
annoconus infans
C. angustiforatus
142
143
144
145
146
147
19r
18r
17r
Alpina
Rem. Inter. Colomi
Chitin.
Para.
Dalmasi
Mircocanthum Andread. Jacobi
Grandis
Tintinopsella
Subalpina
/Privasensis
Ferasini Elliptica
18n
17n
19n.2n
20n.2n
TITHONIAN BERRIASIAN
Theodosia
Nutzhof
Puerto Escano
Rio Argos
Le Chouet
Arcevia
Foza
Sidi Khalif
Lokut
Kurovice
Font de
St Bertrand
Fig. 2. FADS of selected calcareous nannofossils in the Upper Tithonian to Lower Berriasian, calibrated with magnetozones and calpionellid biozones
(modified from Wimbledon, 2016, Wimbledon et al., 2017, Bakhmutov et al., in press)
Continuous vertical lines shows the distribution of FADS, in publications up to 2009 (after Casellato, 2010). Coloured spots represent records of FADS at lower
stratigraphic levels (After Speranza et al., 2005; Lukeneder et al., 2010; Casellato, 2010; Wimbledon et al., 2013; Hoedemaeker et al., 2016: Svobodova, Kostak,
2016; Grabowski et al., 2017; Švábenická et al., 2017; Bakhmutov et al., 2018, in press; Ebra et al., 2018, in press; Gardin, unpublished). NB: At Le Chouet,
magnetic subzone M19n.1r was not detected, so although N. steinmannii minor and N. kamptneri minor are shown in M19n.1n, their FADs may fall in M19n.2n.
The record of N. wintereri in M19r at Nutzhof is currently being re-examined
184 William A.P. Wimbledon
results from Las Loicas are still awaiting publication, but those from Arroyo Lonconche (Llanos et al., 2017) are intriguing,
as they put the Noduliferum Zone base not in magnetozone M19n, but higher, in M16r. At Las Loicas, Lopez Martinez et al.
(2017) have since identied an assemblage with predominant small globular Calpionella alpina (albeit co-occurring with
Crassicollaria brevis, C. remanei and C. massutiniana) and the Alpina Subzone at the base of the Noduliferum Zone (Fig. 1).
All this makes it an exciting time for Tethyan: Andean correlations.
Work must now focus on expanding efforts to identify proxies for the C. alpina level in the more problematic regions. For
instance, the application of belemnites in Siberia and the Pacic (Dzyuba, 2012). It seems that the comparatively little studied
Siberian boreal areas, though with disappointingly poor preservation of signicant nannofossil taxa (Zanin et al., 2012) and
a discontinuous record of endemic ammonites near the boundary (Schnabl et al., 2015) (Fig. 1), still have considerable cor-
relation potential with other fossil groups, and they need better (and much more) targeting of new localities for magnetostrati-
graphic study. In this context, Vishnevskaya (2017) records calcareous dinoagellates in Siberia (Stomiosphaerina proxima,
Colomisphaera tenuis, C. lapidosa, and C.? fortis) with radiolarians in the presumed Berriasian Bazhenovo Formation. This
demands more research, as, if conrmed, they would be of use as proxies for calpionellids.
Calcareous dinoagellate cysts are common fossils in the Tithonian to Berriasian of European and North African Tethys.
They appear to have much potential as accessories to the calpionellids, though there are rather few recent accounts and the
stratigraphic ranges of some species has yet to become static (e.g. Stomiosphaera moluccana and Colomisphaera pieniensis:
Wimbledon et al., 2013; and below). But of notably useful species, in the Balkans, the rst appearance of S. proxima has been
recorded in the upper Crassicollaria Zone, and said to have its FAD at the base of the Colomi Subzone, though it appears rst
in the Remanei Subzone in SE France. This restriction to the Crassicollaria Zone was emphasized by Rehakova (2000) (see
also Lukeneder et al., 2010: but note Lopez et al., 2013).
C. fortis only just pre-dates S. proxima (appearing pre-Crassicollaria Zone), and its range straddles the upper Crassicol-
laria and Calpionella zones, affording a wider stratigraphic bracket: this proves to be the case in some French sites (e.g. Tre
Maroua and St Bertrand). If such occurrences could be conrmed and consistently proved in Siberia (and perhaps the Russian
Platform), it would be a step forward in accuracy in trying to correlate with the Crassicollaria/Calpionella zonal boundary.
Vishnevskaya’s FAD of C.? fortis in Siberia appears to be very high (Analogus Zone) and that of S. proxima is shown lower
than one should expect (Exoticus Zone, ?M20n) as compared to Tethys, when the Alpina J/K boundary (M19n.2n) has been
correlated with the Siberian Taimyrensis Zone. However, the original assignment of magnetozones numbers in Siberia, at
Nordvik, may merit reconsideration. The reversed intervals, identied as M19n.1r, M18r and M17r, are of limited, and simi-
lar, thickness (Schnabl et al., 2015). With a fresh mind and no preconceptions, perhaps one might reconsider the original
magnetozone notation of Houša et al. and assign different numbers. That being as it may, more research on calcareous dino-
agellates is an absolute priority in boreal regions.
Most recently, Ivanova and Kietzmann (2017) record dinoagellate cysts in the Andes: Colomisphaera tenuis, C. fortis,
S. proxima (lower Noduliferum Zone) and S. wanneri (upper Noduliferum Zone). The S. wanneri biozone (Arroyo Lonco-
che) they characterise as Upper Berriasian (Noduliferum to Damesii zones). S. wanneri has been found higher in the
Berriasian in the Carpathians, but it has also been collected in the Lower Berriasian in southern Ukraine (Bakhmutov et al.,
2018, in press), and it seems that it appears similarly early in France (Font de St Bertrand – Elliptica Subzone: Tre Maroua
– Simplex Subzone), as does C. vogleri (Simplex Subzone). Kietzmann and Llanos (2017), discussing the results of Lopez
Martinez et al. (2017), would correlate S. wanneri and S. proxima with the European Berriasian, as above, and have Nanno-
conus steinmannii steinmannii in the Andes indicate correlation with M17r in Tethys: but see Fig. 2.
CONCLUSIONS
• No fossil species has anything like a global distribution in the Tithonian-Berriasian interval. Though Calpionella alpina
is the most widespread.
• The base of M18r does not coincide with any consistent biotic marker at sites recently studied for magnetostratigraphy,
and the same is true of the base of M19n.2n.
• The traditional Berriasella jacobi Subzone will play no part in any denition of the base of the Berriasian, nor can the
species Berriasella jacobi [=Strambergella jacobi].
• Calpionellids (calibrated with magnetostratigraphy) provide the most effective primary J/K boundary marker, the Cras-
sicollaria to Calpionella turnover, i.e. the Colomi/Alpina subzone boundary as shown in Figs 1, 2.
185Developments with xing a Tithonian/Berriasian (J/K) boundary
• In June 2016, the Berriasian Working Group voted, by a large majority (76%), to adopt the Crassicollaria/Calpionella
turnover and base of the Alpina Subzone as the primary marker for the base of the Berriasian Stage: the WG now focusses
on identication of the best candidate site for a GSSP.
• This level is bracketed by a number of nannofossil FADs (Fig 2).
• Correlative advances in Argentina are exciting, and amplication of the rst palaeomagnetic results and of recent C. al-
pina nds are anticipated.
• In austral regions, most notably in the Andes, some of the Tethyan nannofossil marker species have been identied (along-
side endemic ammonites), including species which are proxies for the base of the Alpina Subzone, as they have in Tibet.
• New nds of Tethyan calcareous dinoagellate cysts in the Andes indicate their usefulness and potential as secondary
markers.
• In Siberia, at one site, Nordvik, it is possible to approximate the horizon of Calpionella alpina (in mid M19n.2n): close
below the base of the Tehamaensis (belemnite) Zone and close above the ‘oating’ Taimyrensis (ammonite) zonal base.
Earlier nds of calcareous nannofossils in Siberia have yet to be followed up. Identications there of calcareous dinoag-
ellates have great potential, and it is to be hoped they will provide proxies for calpionellid datums, as in austral regions.
REFERENCES
ARKADIEV V., GUZHIKOV A., BARABOSHKIN E., SAVILIEVA J., FEODEROVA A., SHUREKOVA O., PLATONOV E., MANIKIN A.,
2017, in press – Biostratigraphy and magnetostratigraphy of the upper Tithonian–Berriasian of the Crimean Mountains. Cretaceous
Research.
BENZAGGAGH M., CECCA F., SCHNYDER J., SEYED-EMAMI K., REZA MAJIDIFARDE M., 2012 – Calpionelles et microfaunes
pélagiques du Jurassique supérieur – Crétacé inférieur dans les Formations Shal et Kolur (Montagnes du Talesh, chaîne de l’Elbourz,
Nord-Ouest Iran). Répartition stratigraphique, espèces nouvelles, revision systématique et comparaisons regionals. Annales de Paléon-
tologie, 98: 253–301.
BAKHMUTOV V.G., HALÁSOVÁ E., IVANOVA D.K., JÓZSA Š., REHÁKOVÁ D., WIMBLEDON W.A.P., 2018, in press – Biostrati-
graphy and magnetostratigraphy of the Uppermost Tithonian – Lower Berriasian in the Theodosia area of southern Ukraine. Geological
Quarterly.
CASELLATO C.E., 2010 – Calcareous nannofossil biostratigraphy of Upper Callovian – Lower Berriasian successions from Southern
Alps, North Italy. Rivista Italiana di Paleontologia e Stratigraa, 116: 357–404.
CELESTINO R., WOHLWEND S., REHÁKOVÁ D., WEISSERT H., 2016 – Carbon isotope stratigraphy, biostratigraphy and sedimento-
logy of the Upper Jurassic – Lower Cretaceous Rayda Formation, Central Oman Mountains. Newsletters on Stratigraphy, 50: 91–109.
DZYUBA O.S., 2012 – Belemnites and biostratigraphy of the Jurassic–Cretaceous boundary deposits of northern east Siberia: new data on
the Nordvik Peninsula. Stratigraphy and Geological Correlation, 20: 53–72.
ELBRA T., SCHNABL P., ČÍŽKOVÁ K., PRUNER P., KDÝR Š., GRABOWSKI J., REHAKOVÁ D., SVOBODOVÁ A., FRAU C.,
WIMBLEDON W.A.P., 2018, in press – Palaeo- and rock magnetic investigations across Jurassic–Cretaceous boundary at St Ber-
trand’s Spring, Drome, France – Applications to magnetostratigraphy. Studia Geophysica et Geodaetica.
FERNANDEZ CARMONA J., RICCARDI A.C., 1998 – Primer hallazgo de Chitinoidella Doben en el Tithoniano de la Argentina. In:
X Congreso Latinoamericano de Geología y VI Congreso Nacional de Geología Económica (Buenos Aires).
FERNANDEZ CARMONA J., RICCARDI A.C., 1999 – Primer reporte de calpionélidos calcáreos del Cretácico inferior – Berriasiano de
la provincia del Tethys en la República Argentina: conexión Tethys–Pacíco, 465–466 In: 5th Simposio sobre o Cretaceo do Brasil,
Boletim.
FRAU C., BULOT B.G., REHÁKOVÁ, D., WIMBLEDON W.A.P., 2016 – The revision of the ammonite index species Berriasella jacobi
Mazenot, 1939 and its consequences for the biostratigraphy of the Berriasian Stage. Cretaceous Research, 66: 94–114.
GRABOWSKI J., HAAS J., STOYKOVA K., WIERZBOWSKI H., BRAŃSKI P., 2017 – Environmental changes around the Jurassic/
Cretaceous transition: New nannofossil, chemostratigraphic and stable isotope data from the Lókút section (Transdanubian Range,
Hungary). Sedimentary Geology, 360: 54–62.
IVANOVA D., KIETZMANN D., 2017 – Calcareous dinoagellate cysts from the Tithonian – Valanginian Vaca Muerta Formation in the
southern Mendoza area of the Neuquén Basin, Argentina. Journal of South American Earth Sciences, 77: 150–169.
KIETZMANN D.A., BLAU J., RICCARDI A.C., PALMA R.M., 2011 – An interesting nding of Chitinoidellids (Calpionellidea Bonet)
in the Jurassic–Cretaceous boundary of the Neuquen Basin. 1480–1481 In: Actas XVIII Congreso Geológico Argentino.
KIETZMANN D.A., 2017 – Chitinoidellids from the Early Tithonian–Early Valanginian Vaca Muerta Formation in the Northern Neuquén
Basin, Argentina. Journal of South American Earth Sciences, 76: 152–164.
KIETZMANN D.A., LLANOS P.M.I., 2017, in press – Comment on “Tethyan calpionellids in the Neuquén Basin (Argentine Andes), their
signicance in dening the Jurassic/Cretaceous boundary and pathways for Tethyan–Eastern Pacic connections” by R. López-Mar-
tínez et al., Journal of South American Earth Sciences.
186 William A.P. Wimbledon
LIU Y.-Q., JI Q., JIANG X.-J., XU H., 2013 – U-Pb Zircon Ages of Early Cretaceous Volcanic Rocks in the Tethyan Himalaya at Yang-
zuoyong Co Lake, Nagarze, Southern Tibet, and Implications for the Jurassic/Cretaceous Boundary. Cretaceous Research, 40: 90–101.
LLANOS M.P.I., KIETZMANN D.A., MARTINEZ M.H., PALMA R.M., 2017 – Magnetostratigraphy of the Upper Jurassic–Lower Cre-
taceous from Argentina: implications for the J–K boundary in the Neuquén Basin. Cretaceous Research, 70: 189–208.
LÓPEZ-MARTÍNEZ R., BARRAGÁN R., REHÁKOVÁ D., 2013. The Jurassic/Cretaceous boundary in the Apulco area by means of
calpionellids and calcareous dinoagellates: an alternative to the classical Mazatepec section in eastern Mexico. Journal of South
American Earth Sciences, 47: 142–151.
LOPEZ-MARTÍNEZ R., AGUIRRE-URRETA B., LESCANO M., CONCHEYRO A., VENNARI V., RAMOS V.A., 2017 – Tethyan cal-
pionellids in the Neuquén Basin (Argentine Andes), their signicance in dening the Jurassic/Cretaceous boundary and pathways for
Tethyan-Eastern Pacic connections. Journal of South American Earth Sciences, 78: 116–125.
LUKENEDER A., HALÁSOVÁ E., KROH A., MAYRHOFER S., PRUNER P., REHÁKOVÁ D., SCHNABL P., SPROVIERI M., WAG-
REICH M., 2010 – High resolution stratigraphy of the Jurassic–Cretaceous boundary interval in the Gresten Klippen Belt (Austria).
Geologica Carpathica, 61: 365–381.
PRICE G.D., ISTVAN FŐZY I., PÁLFY J., 2016 – Carbon cycle history through the Jurassic–Cretaceous boundary: A new global δ13C
stack. Palaeogeography, Palaeoclimatology, Palaeoecology, 451: 46–61.
REHÁKOVÁ D., 2000 – Calcareous dinoagellates and calpionellid bioevents versus sea-level uctuations recorded in the West Carpa-
thians (Late Jurassic/Early Cretaceous pelagic environments). Geologica Carpathica, 51: 229–243.
REMANE J., 1991 – The Jurassic–Cretaceous boundary: problems of denition and procedure. Cretaceous Research, 12: 447–453.
SCHNABL P., PRUNER P., WIMBLEDON W.A.P., 2015 – A review of magnetostratigraphic results from the Tithonian–Berriasian of
Nordvik (Siberia) and possible biostratigraphic constraints. Geologica Carpathica, 66: 489–498.
SPERANZA F., SATOLLI S., MATTIOLI E., CALAMITA F., 2005 – Magnetic stratigraphy of Kimmeridgian–Aptian sections from Um-
bria-Marche (Italy): new details on the M polarity sequence. Journal Geophysical Research, 110: B12109.
ŠVÁBENICKÁ L., REHÁKOVÁ D., SVOBODOVÁ A., 2017 – Calcareous nannofossils of the Jurassic–Cretaceous boundary strata in
the Puerto Escaño section (southern Spain) – biostratigraphy and palaeoecology, 252. In: 10th Int. Symp. Cretaceous. Berichte der
Geologischen Bundesanstalt, Band 120.
SVOBODOVA A., KOSTAK M., 2016 – Calcareous nannofossils of the Jurassic–Cretaceous boundary strata in the Puerto Escaño section
(southern Spain) – biostratigraphy and palaeoecology. Geologica Carpathica, 67: 223–238.
VISHNEVSKAYA V.S., 2017 – The Jurassic–Cretaceous boundary: radiolarian and calcareous dinoagellate potential biomarkers. Geo-
logical Quarterly, 61: 641–654.
VENNARI V.V., LESCANO M., NAIPAUER M., AGUIRRE-URRETA B., CONCHEYRO A., SCHALTEGGER U., ARMSTRONG R.,
PIMENTEL M., RAMOS V.A., 2014 – New constraints in the Jurassic Cretaceous boundary in the High Andes using high-precision
U-Pb data. Gondwana Research, 26: 374–385.
WIMBLEDON W.A.P., 2013 – Warsaw remarks – Berriasian progress. Volumina Jurassica, 12: 107–112.
WIMBLEDON W.A.P., REHÁKOVÁ D., PSZCZÓŁKOWSKI A., CASELLATO C., HALÁSOVÁ E., FRAU C., BULOT L.G.,
GRABOWSKI J., SOBIEŃ K., PRUNER P., SCHNABL P., CIZKOVA K., 2013 – A preliminary account of the bio- and magneto-
stratigraphy of the Upper Tithonian – Lower Berriasian interval at Le Chouet, Drôme (SE France). Geologica Carpathica, 64: 437–460.
WIMBLEDON W.A.P., 2016 – The Tithonian/Berriasian stage boundary and the base of the Cretaceous System, 290. In: XIIth Jurassica
Conference. IGCP 632 and ICS Berriasian workshop. Slovak Academy of Sciences.
WIMBLEDON W.A.P., MOHIALDEEN I.M.J., ANDREINI G., REHÁKOVÁ D., STOYKOVA K., 2016 – Jurassic/Cretaceous boundary
beds in Kurdistan – a preliminary note on wider correlations, 269–276. In: Special Issue – GeoKurdistan II. Journal of Zankoy Sulai-
mani Part A.
WIMBLEDON W.A.P. et al., 2017 – The Tithonian/Berriasian stage boundary and the base of the Cretaceous System. 10th Int. Symp.
Cretaceous. Berichte der Geologischen Bundesanstalt, Band 120.
ZANIN Y.N., ZAMIRAILOVA A.G., EDER V.G., 2012 – Some Calcareous Nannofossils from the Upper Jurassic – Lower Cretaceous
Bazhenov Formation of the West Siberian Marine Basin, Russia. The Open Geology Journal, 6: 25–31.
... It is not always clear in the literature what the terms 'Boreal' and 'Subboreal' refer to paleogeographically. Most usefully, Ogg et al. (2016, p. 170) and Wimbledon (2017) speci ed distinct Dorset, North Sea, Nordvik, and Russian Platform regional zonations using geographic names; but confusingly, Ogg et al. (2016, p. 175), following Cope (2008) and others, labelled the eastern English zonation as 'Boreal'. Shurygin et al. (2011) decried the common practice of mixing zones from di erent faunal realms into single regional hybrid zonations, particularly the insertion of Russian Platform zones into the high Arctic zonation. ...
... The latest Jurassic Arctic Canadian ammonite and Buchia occurrences have been tied to the northern Siberia ('high Boreal') zonation provided by TSC, which incorporates recent interpretations for the Jurassic-Cretaceous boundary interval from Nordvik (Schnabl et al., 2015). The standard columns o ered in TSC illustrate the base of the Cretaceous within the Subboreal (northwestern European) Subcraspedites preplicomphalus Zone and within the high Boreal (northern Siberia) Craspedites taimyrensis Zone, in accordance with the current proposal for the base of the Cretaceous (Wimbledon, 2017, Fig. 1). ...
... The proposal to de ne the base of the Cretaceous in the Tethyan realm, currently in development, uses the base of the widespread calpionellid Calpionella alpina Zone as a primary marker in a 'sandwich' with secondary markers, including nannofossil and calcareous dino agellate-cyst events, ammonites (Delphinella), and magnetic anomalies (Wimbledon, 2017). Magnetic reversal correlations, and perhaps belemnites (Arctoteuthis tehamaensis), recognized in northern Siberia may permit correlation of the base of the Cretaceous from the Boreal into the Tethyan realm (e.g. ...
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... The Cretaceous is the only Phanerozoic system that does not yet have an accepted global boundary definition, despite over a dozen international conferences and working group meetings dedicated to the issue since the 1970s (e.g., reviews by Zakharov et al., 1996;Cope, 2007;Wimbledon, 2017). Difficulties in assigning a global Jurassic/Cretaceous boundary are the product of historical usage, the lack of any major faunal change between the latest Jurassic and earliest Cretaceous, a pronounced provincialism of marine fauna and flora and a concentration of previous studies on often endemic ammonites (Fig. 27.2). ...
... The current Berriasian Working Group of the International Commission on Cretaceous Stratigraphy has worked to integrate regional ammonite zonations, calpionellid zones, calcareous nannofossil datums, palynomorphs, and magnetostratigraphy (e.g., Schnabl et al., 2015;Wimbledon, 2017;summarized in Fig. 27.2). Their emphasis is on identifying a GSSP level near markers of both regional and global significance. ...
... The absence of the ammonite species B. jacobi (5Strambergella jacobi) in the lower part of the nominal B. jacobi Subzone rules this taxon out as a GSSP marker (Frau et al., 2016;Wimbledon, 2017). It further appears that there are no ammonite-zone boundaries that are synchronous among the main European regions within the basal Cretaceous transition interval. ...
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... The International Commission of Stratigraphy (ICS) has recommended establishing a boundary point or Global Standard Section and Point (GSSP) (Remane et al. 1996) and since then works by the Berriasian Working Group (BWG) of the International Subcommission on the Cretaceous System (ISCS) has been focused on precise definitions of stage boundaries around the JKB and their potential for global correlations. Calpionellids have been considered as excellent stratigraphic biomarkers for defining the Tithonian-Berriasian boundary, with the base of the Alpina Sub-zone as a primary marker for the lower limit of the Berriasian (Wimbledon 2017). ...
... Calpionella Zone (Alpina Subzone) (AZ67-AZ76: 18.3 m; TB93-TB95: 2.85 m) Only the lower part of the Alpina Subzone of Calpionella Zone is reached in this work. Its base is eaily defined by the «acme» of small sphaerical Calpionella alpina, a particular event considered by Wimbledon (2017) as a primary marker for the Jurassic-Cretaceous boundary. Within this subzone, a low calpionellid diversity is observed with the abundance of Calpionella alpina, Crassicollaria parvula and still present, but rare, Crassicollaria massutiniana and Crassicollaria brevis. ...
High resolution calpionellid biozonation of Upper Tithonian reference sections in NE Algeria (Jebel Azreg, Aurès Range; Jebel Toumbaït, Aïn Yaghout Mounts): correlations and geodynamic implications
Article
Full-text available
  • May 2024
The stratigraphic problem of the Jurassic-Cretaceous boundary (JKB) is still the object of a warm international debate. Around this limit, the Upper Tithonian substage has been the subject of significant stratigraphic investigations throughout the Tethyan Realm areas. On the southern Tethys Margin of the Maghreb, our recent works in NE Algeria have revealed sections, where good Upper Jurassic outcrops are considered as promising for the definition of a Global Standard Section and Point (GSSP) for the Jurassic-Ctretaceous boundary. In this line of interest, a high resolution calpionellid biozonation of Upper Tithonian successions from two bed-by-bed sampled key sections in the Aurès (Jebel Azreg) and Aïn Yaghout Mounts (Jebel Toumbaït) of NE Algeria is proposed here for the first time. The Crassicollaria and Calpionella Zone limits, encasing two subzones and six stratigraphic horizons, are identified. Within these sections, calpionellid distribution and resulting biostratigraphic units fit the standards referred to for the Tethyan Realm. The identified marker bioevents and associations confirm the high biostratigraphic potential of calpionellids for the JKB definition in the North Africa Maghrebian Chains. Correlation transects reveal important thickness and facies variations interpreted as the result of a synsedimentary tectonic control implying NW–SE, E-W and NE-SW major faults that led to the individualization of a mozaic of highs and depressions where Upper Tithonian deposits onset. A proposed interpretative model replaces the Upper Tithonian study successions in their regional geodynamic context.
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... To the topmost of the RB.I-A unit, a notable abundance of isometric small-sized Calpionella alpina (Fig. 4G) is observed since the bed 210 at the base of which we place herein the lower limit of the Alpina Subzone (Calpionella Zone) of calpio nellids sensu Remane et al. (1986) (= "B" Zone of Remane (1963)). Correlated with the base of the lowermost Berriasian Jacobi Zone of ammonites (Enay & Geyssant 1975;Cecca et al. 1989;Benzaggagh & Atrops 1995a), this limit is also considered as the primary marker of the Jurassic-Cretaceous boun dary (Wimbledon 2017). ...
... This zone starts with the acme of small sphaerical variety of C. alpina, also considered as a primary marker for the Jurassic-Cretaceous boundary (Wimbledon 2017). Its upper part is determined by the base of the Calpionellopsis Zone. ...
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... In June 2016, the Berriasian Working Group (BWG1) voted to adopt the Crassicollaria/Calpionella turnover and base of the Alpina Subzone as the primary marker for the base of the Berriasian stage (Wimbledon, 2017). It led to misunderstanding (see the example above) that Crassicollaria/Calpionella turnover is not the FAD but the acme event of Calpionella alpina, as it was clarified later in Wimbledon et al. (2020, p. 61): "marked increase [acme] in small globular Calpionella alpina….. ...
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.
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... Currently, there are two opposing views regarding the definition of the J/K boundary. The past (2008-2020) Berriasian Working Group supports the position of this last unstandardized Mesozoic stage boundary to be defined at the T/B boundary (Wimbledon, 2017;Wimbledon et al., 2020a), generally known as the Kilian's (or Mazenot's) view (see É nay, 2020 for a review). The second, known as the Oppel's (or d'Orbigyn's) view, suggests shifting of the J/K system boundary to the B/V stage boundary (Granier, 2019a;É nay, 2020;Granier et al., 2020a). ...
Calibrating the Late Jurassic–Early Cretaceous shallow and deep marine bioevents by quantitative biostratigraphy: A synthesis from the Pontides Carbonate Platform (Turkey)
Article
  • Jun 2022
  • EARTH-SCI REV
The Late Jurassic–Early Cretaceous is an interval of unstandardized stages and includes the only Mesozoic system boundary without a Global Boundary Stratotype Section and Point – the Jurassic/Cretaceous (J/K) boundary. Recent researches have been mainly focused on deep marine continuous successions from the Tethyan region and provided important progress in calibration of pelagic bioevents. Correlation of these pelagic zonations with the schemes from shallow marine deposits is still obscure. Biostratigraphical data from marginal carbonates containing fossils both from the platform and basinal facies can provide the required links between these two distinct depositional environments. This kind of Upper Jurassic–Lower Cretaceous carbonates widely crop out in the Pontides (northern Turkey) in close association with related shallow and deep marine successions. A biostratigraphical dataset including 17 stratigraphical sections from this Pontides Carbonate Platform is synthesized. The fossil data include organisms from various depositional environments (i.e., benthic and planktonic foraminifers, calpionellids, algae, microencrusters and crinoids) and provides 139 bioevent datums (stratigraphic levels). This fossil dataset is analyzed through the methods of Graphic Correlation (GC) and Unitary Associations (UA) in order to overcome facies (past depositional conditions) controlled local biohorizons and calibrate fossil datums from unrelated phylogenies. Calibration of the Pontides Composite Reference Section (CSRS) with the Geological Time Scale (2020) reveals relative positions of both shallow and deep marine bioevents with respect to the Oxfordian–Hauterivian stage boundaries. The Tithonian/Berriasian and the Berriasian/Valanginian boundaries can be easily delineated by calpionellid bioevents in pelagic successions. However, no synchronous shallow marine first/last occurrence bioevents are available for both of these levels. Increased rates of originations toward Berriasian provide clustering of bioevents around the Tithonian/Berriasian boundary and brackets for both pelagic and shallow marine deposits. Several last occurrences provide unreliable approximations for the Berriasian/Valanginian boundary in neritic deposits. The species richness declines mid-Berriasian onward in accordance with the general trend toward lower sea levels through the late Tithonian into the Valanginian that diminished shallow marine factories and paved the way for a general Valanginian–Hauterivian drowning phase for the Tethyan carbonate platforms. This also adds difficulties in finding reliable origination events in the shallow marine environments for this extinction dominated interval.
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... Recently, the Berriasian Working Group of the International Commission on Stratigraphy has voted the position of the Jurassic-Cretaceous boundary at the base of the Calpionella Zone in the middle part of M19n.2n Subchron (Wimbledon 2017). ...
Facies analysis and stratigraphy across the Jurassic-Cretaceous boundary in a new basinal Tithonian–Berriasian section of the Vaca Muerta Formation, Las Tapaderas, Southern Mendoza Andes, Argentina
Article
  • Mar 2021
  • J S AM EARTH SCI
This paper presents a multidisciplinary study of a new basinal section of Tithonian-Berriasian the Vaca Muerta Formation at Las Tapaderas area, including detailed, biostratigraphic, sedimentologic, sequence stratigraphic and cyclostratigraphic analysis. Biostratigraphy based on ammonite, calpionellids and calcareous dinoflagellate cysts indicate that Las Tapaderas section spans through the Lower Tithonian - lowermost Upper Berriasian, however, its upper part is covered through an erosive unconformity by Pleistocene volcaniclastic deposits, and therefore Las Tapaderas section could reach the Lower Valanginian. Two facies associations were identified, corresponding to basinal and distal outer ramp subenvironments. Recognition of flooding surfaces allowed the identification of three composite depositional sequences and eight high-frequency depositional sequences, which can be correlated with other sections throughout the basin. Cyclostratigraphic analysis based on the recognition of marlstone/limestone couples (elementary cycles) allowed to build a time series based on bed thickness. Fourier analysis indicates the characteristic mid latitude precession-eccentricity syndrome, with 220 precessional cycles (∼20.4 and ∼23 kyr), 53 low frequency eccentricity cycles (∼79, ∼90 and ∼140 kyr) and 11 high frequency eccentricity cycles (∼400 kyr). Spectral analysis also allowed to recognize the presence of the obliquity cycle (38.5 kyr), which has been erratically recorded in the Vaca Muerta Formation. Our data allowed the construction of an orbital scale, calibrated by cosmopolitan markers (calpionellids and calcareous dinoflagellate cysts), for this section. The precise bio- and cyclostratigraphic location of the Jurassic-Cretaceous boundary was established for this section. The sedimentation rate was studied at the scale of the precession cycle, showing values between 0.6 and 3 cm/kyr, while at the low-frequency eccentricity scale it shows values between 1 and 2 cm/kyr.
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... Beyond the Mediterranean area, in NW Europe and Russia, calpionellids are not common (e.g. Pszczółkowski, 2016;Wimbledon, 2017) and magnetostratigraphy is determined only in a few sections (Ogg et al., 1994;Houša et al., 2007;Schnabl et al., 2015;Manikin et al., 2019). Additional correlation possibilities are limited due to the palaeogeographic provincialism of ammonites between the Tethyan and Boreal domains (e.g. ...
Upper Berriasian chemostratigraphy, clay minerals and calcareous nannofossils of the Barlya section (Western Balkan, Bulgaria): Implications for palaeoclimate and productivity changes, and stratigraphic correlations across the Alpine Tethys
Article
  • Jan 2021
  • PALAEOGEOGR PALAEOCL
Upper Berriasian chemostratigraphic, clay mineral and calcareous nanofossil data are presented from a precisely dated hemipelagic section of Barlya (Western Balkan, Bulgaria). The section covers an interval from the upper part of the lower Berriasian (Calpionella elliptica Subzone, magnetozone M17r) to the lowermost Valanginian (Calpionellites darderi Subzone, magnetozone M14r). The study aims to reconstruct the major palaeoenvironmental changes (variations in lithogenic input, palaeoredox and palaeoproductivity) and their relation to palaeoclimate and regional tectonic regime, as well as their application to stratigraphic correlations with the Vocontian Basin and Jura Mts. A long-term increase in terrigenous input during the late Berriasian was controlled mostly by the orogenic activity in the NeoTethyan Collision Zone and to a lesser degree by climate humidification, as revealed by variations in kaolinite content and in lithogenic proxies (Ti/K, Th/K, Ti/Al and Zr/Rb ratios). A good correlation is observed between geochemical palaeoproductivity proxies (sedimentation rates of non-detrital (excess or authigenic) portions of P, Zn and Cd) and nannofossil fluxes, determined as the total abundance and species richness. Major calcareous nannofossil peaks, represented by high-diversity and high-abundance nannofossil assemblages, fall within the low-productivity intervals. A smaller peak formed by a low-diversity and high-abundance assemblage, dominated by Watznaueria barnesiae/fossacincta, coincides with the variable, but mostly high-productivity interval, which indicates high plasticity of Watznaueria concerning to environmental conditions. Additionally, trophic changes seem to correspond to bulk rock carbon-isotopic composition, with rising δ¹³Ccarb values in more oligotrophic intervals. This offers perspectives for long-distance chemostratigraphic correlations between pelagic and platform sections, supplementing traditional schemes based on bio- and sequence stratigraphy. A holostratigraphic correlation is proposed between the Western Balkan (Barlya section), Vocontian Basin (Berrias and Monclus sections) and Jura Mts (La Chambotte section) based on bio-, magnetic and carbon-isotope stratigraphy, as well as climatic and palaeoproductivity proxies.
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Jurassic-Cretaceous transition in the Transdanubian Range (Hungary): integrated stratigraphy and paleomagnetic study of the Hárskút and Lókút sections
Article
  • Mar 2021
  • NEWSL STRATIGR
A high-resolution stratigraphic calibration is presented using biostratigraphic (calpionellids, calcareous dinoflagellates, calcareous nannofossils), magnetostratigraphic and chemostratigraphic (δ13C, Al) techniques on the uppermost Jurassic–lowermost Cretaceous sedimentary successions from Hárskút and Lókút in the Bakony Mountains (Transdanubian Range, Hungary). These localities are characterized by noticeably distinct facies developments, despite their geographic proximity. Relatively condensed deposits of early Tithonian–early Valanginian age (ca. 15 m thick; M22r–M13r magnetozones) in the Hárskút succession revealed stratigraphic discontinuities; however, our methodology allowed us to identify hiatuses and condensation levels within the magnetostratigraphic record. The Tithonian–Berriasian boundary, marked by the base of the Alpina calpionellid Subzone, falls in the M19n magnetozone, below the base of the NC0 calcareous nannofossil Zone. In turn, the Berriasian–Valanginian boundary, marked by the base of the Calpionellites darderi calpionellid Subzone, is located in magnetozone M14r, below the base of the NC3 nannofossil Zone. A continuous record of Maiolica-type lower Berriasian limestone is exposed in the Lókút succession, between magnetozones M21r–M17n. A consistently decreasing lithogenic influx throughout the Tithonian–lower Berriasian is correlated with a Tithonian trend of climate aridization, while elevated upper Berriasian influxes primarily correspond to tectonic activity within the Neotethyan Collision Belt. The demise of the Saccocoma microfacies and the timing of Nannofossil Calcification Events are interpreted as both mutually related to paleoceanographic changes.
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The jurassic-cretaceous boundary in Boreal Russia: Radiolarian and calcareous dinoflagellate potential biomarkers
Article
Full-text available
  • Jan 2017
  • GEOL Q
The International Berriasian Working Group (ISCS) suggested primary and secondary marker “datums” to fix the basal Berriasian boundary and thus to detine the Jurassic-Cretaceous boundary (Wimbledon et al., 2011, 2013). Two primary markers Calpionella, as well as calcareous nannoplankton, are practically unknown in the Boreal Realm. Testing and calibration of these markers, as well as of fossils of radiolarians and other signals, in the most complete sections, were declared as an important task for the near future. In the Tethys, the Jurassic-Cretaceous boundary based on radiolarians falls inside zone UAZ 13 of Baumgartner et al. (1995), whereas in the palaeo-Pacific it corresponds to the boundary between zones 4 and 5 of Pessagno et al. (2009), and in boreal Siberia it probably falls between the biohorizons of Parvicingula haeckeli and P. khabakovi. The radiolarian events at the Jurassic-Cretaceous boundary in the boreal successions of Russia can be proposed to be used as an additional biomarkerto help develop new integrated boundary criteria. Thus, as the first appearance of the zonal species Calpionella alpina, which defines the Jurassic and Cretaceous boundary, coincides with the first occurrence of the calcareous dinocyst zonal species Stomiosphaerina próxima (Reháková, 2000), it is logical to propose a calcareous dinoflagellate, widely represented in the Upper Jurassic-Lower Cretaceous Bazhenovo Formation of Siberia, as a secondary marker.
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Carbon isotope stratigraphy, biostratigraphy and sedimentology of the Upper Jurassic – Lower Cretaceous Rayda Formation, Central Oman Mountains
Article
Full-text available
  • Jan 2017
  • NEWSL STRATIGR
Carbon isotope chemostratigraphy and calpionellid biostratigraphy were used in this study to improve the stratigraphic resolution of the Upper Jurassic–Lower Cretaceous Rayda Formation and examine the expression of the Valanginian C-isotope event in the SE-Tethys. This integrated stratigraphic framework allows for a better correlation between south-eastern and western Tethys records and to obtain a better understanding of the oceanographic system on a regional scale. During the Late Jurassic, a major transgression induced a fast flooding of the Arabian Platform and lead to the deposition of the Rayda Formation. Red crinoidal limestones and submarine hardgrounds at the base of the formation are signs of condensed sedimentation influenced by changing current systems along the passive margin shelf. The following deposition of Maiolicatype micritic limestones with chert nodules recorded the establishment of pelagic conditions which presumed during the earliest Cretaceous and ended with the onset of the hemipelagic sediments of the Salil Formation. The upper part of the Rayda Formation, so far considered as Berriasian-earliest Valanginian in age, is here ascribed to the Upper Valanginian. The established δ13C-curve records the distinct Valanginian C-isotope event (CIE) in the uppermost part of the Rayda Formation and the lowermost part of the Salil Formation. The age of the excursion is underpinned by calpionellid biostratigraphy.
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Calcareous nannofossils of the Jurassic/Cretaceous boundary strata in the Puerto Escaño section (southern Spain) - Biostratigraphy and palaeoecology
Article
Full-text available
  • Jun 2016
We obtained material from the Puerto Escano section (southern Spain) to study the Jurassic/Cretaceous (J/K) boundary interval. The same samples had already been processed for magnetostratigraphic studies and biostratigraphic zonation based on calpionellids and ammonites (Pruner et al. 2010), but not for calcareous nannofossils. The aim of this study was to process the samples using micropalaeontological analysis and to compare and calibrate results for calcareous nannofossils with existing magnetostratigraphic and other biostratigraphic data. The calcareous nannofossil assemblage was dominated by the genera Watznaueria, Cyclagelosphaera, Nannoconus, Conusphaera and Polycostella. Several nannofossil bioevents were recorded on the basis of the distribution of stratigraphically important taxa, including zonal and subzonal markers. Based on the lowest occurrences (LO) of M. chiastius, N. globulus minor, N. wintereri, N steinmanii minor, N. steinmannii steinmannii, N. kamptneri minor and N. kampteri kamptneri, two nannofossil subzones (NJT 15b, NJT 17a) and two nannofossil zones (NJT 16, NK-1) were recognized. The paper introduces new palaeoecological data based on geochemical analysis and macrofauna occurrences.
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Environmental changes around the Jurassic/Cretaceous transition: New nannofossil, chemostratigraphic and stable isotope data from the Lókút section (Transdanubian Range, Hungary)
Article
  • Aug 2017
  • SEDIMENT GEOL
New biostratigraphical, chemical and stable isotope (C, O) data are presented from the Lókút section (Transdanubian Range, Hungary) representing a ca. 13 m thick continuous succession of Lower Tithonian–Lower Berriasian pelagic limestones. The study is conducted to verify timing of nannofossil events and major palaeoenvironmental changes at the Jurassic/Cretaceous transition including lithogenic input, palaeoredox and palaeoproductivity variations. Nannofossil zones from NJT 16b to NKT have been identified in the Lókút section and correlated with magnetostratigraphy, covering an interval from polarity zone M21r to M18r. The nannofossil Zone NJT 16b spans the interval from the upper part of M21r to lowermost part of M19n2n but its lower limit is poorly defined due to large diachronism in first occurrence (FO) of Nannoconus infans in various Tethyan sections. FOs of N. kamptneri minor and N. steinmannii minor are situated in the topmost part of the M19n2n and lowermost part of M19n1r magnetozones, respectively. They are located ca. 2–2.5 m above the J/K boundary defined as Intermedia/Alpina subzonal boundary, which falls within the lower half of magnetozone M19n2n. The position of first occurrences of these taxa is similar to that from the Puerto Escaño section (southern Spain) and slightly lower than in Italian sections (Southern Alps). Concentrations of chemical element proxies of terrigenous transport (Al, K, Rb, Th) decrease towards the top of the Lókút section, which suggests a decrease in input of terrigenous material and increasing carbonate productivity during the Early Tithonian and the Berriasian. Slight oxygen depletion at the sea bottom (decrease of Th/U ratio), and large increase in concentrations of productive elements (P, Ba, Ni, Cu) is observed upsection. Nutrients supply via upwelling seems to be the most likely explanation. Increase in phosphorus accumulation rate and a microfacies change from Saccocoma to calpionellid dominated took place in the polarity chron M19r, which apparently coincided with the worldwide Nannofossil Calcification Event, related to a bloom of strongly calcified calcareous nannoplankton taxa. Deposition in the Lókút area was probably affected by long-term climatic trends: aridization and warming. Decreasing δ¹³C values of bulk carbonates throughout the Tithonian and the Berriasian are interpreted as a result of a global trend of accelerated carbonate productivity supported by local factors such as increased upwelling intensity, and a possible change in the composition of carbonate mud.
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Tethyan calpionellids in the Neuquén Basin (Argentine Andes), their significance in defining the Jurassic/Cretaceous boundary and pathways for Tethyan-Eastern Pacific connections
Article
  • Jun 2017
  • J S AM EARTH SCI
The study of calpionellid distribution in the well-documented Las Loicas section of the Vaca Muerta Formation in the Neuquén Basin, Argentine Andes, allows the recognition of the upper part of the Crassicollaria Zone and the lower part of Calpionella Zone across the Jurassic/Cretaceous boundary. The Crassicollaria Zone, Colomi Subzone (Upper Tithonian) is composed of Calpionella alpina Lorenz, Crassicollaria colomi Doben, Crassicollaria parvula Remane, Crassicollaria massutiniana (Colom), Crassicollaria brevis Remane, Tintinnopsella remanei (Borza) and Tintinnopsella carpathica (Murgeanu and Filipescu). The Calpionella Zone, Alpina Subzone (Lower Berriasian) is indicated by the explosion of the small and globular form of Calpionella alpina dominating over very scarce Crassicollaria massutiniana. The FAD of Nannoconus wintereri can be clearly correlated with the upper part of Crassicollaria Zone and the FAD of Nannoconus kamptneri minor with the Calpionella Zone. Additional studies are necessary to establish a more detailed calpionellid biozonation and its correlation with other fossil groups. The present work confirms similar calpionellid bioevents in westernmost Tethys (Cuba and Mexico) and the Andean region, strengthening the Paleo-Pacific-Tethyan connections through the Hispanic Corridor already known from other fossil groups.
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Calcareous dinoflagellate cysts from the Tithonian - Valanginian Vaca Muerta Formation in the southern Mendoza area of the Neuquén Basin, Argentina
Article
  • Aug 2017
  • J S AM EARTH SCI
The Late Jurassic – Early Cretaceous marine sediments of the Andean region show an excellent record of different calcareous microfossils, among which calcareous dinoflagellate cysts stand out. Detailed micropaleontological studies of Vaca Muerta Formation (Early Tithonian – Early Valanginian) in the southern Mendoza Neuquén Basin from three sections are conducted with the aim of establishing a major presence of microfossil representatives from different microfossil groups. The analysis of several thin sections from the outcrops reveals a relatively rich micropaleontological assemblage of calcareous dinoflagellate cysts, as well as levels with poor preserved calpionellids and benthic foraminifera. Particularly, calcareous dinoflagellate cyst includes 24 known species (two of them with two subspecies). Some species with biostratigraphic value of the Tethyan region have been identified also in the Andean region: 1) Committosphaera pulla (Borza) and Parastomiosphaera malmica (Borza) are species known only from Lower Tithonian; 2) Colomisphaera tenuis (Nagy) appears in the latest Early Tithonian; 3) Colomisphaera fortis Řehánek and Stomiosphaerina proxima Řehánek are important markers for the latest Late Tithonian – middle Late Berriasian interval; 4) Stomiosphaera wanneri Borza appears in the middle Late Berriasian; 5) Colomisphaera conferta Řehánek and Colomisphaera vogleri (Borza) appear in the Late Berriasian and marked the Berriasian-Valanginian boundary interval; 6) Carpistomiosphaera valanginiana Borza is a marker for the Lower/Upper Valanginian. More detailed studies of these groups will allow their correlation with Tethyan biozones, and contribute to improve biostratigraphic schemes in the Neuquén Basin.
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Chitinoidellids from the Early Tithonian–Early Valanginian Vaca Muerta Formation in the Northern Neuquén Basin, Argentina
Article
  • Mar 2017
  • J S AM EARTH SCI
As part of microfacies studies carried out on the Tithonian – Valanginian carbonate ramp of the Neuquén Basin, two stratigraphic sections of the Vaca Muerta Formation (Arroyo Loncoche and Río Seco de la Cara Cura) were chosen in order to analyze the chitinoidellid content and distribution. Calpionellids in the studied sections are relatively poorly preserved; hyaline calcite walls are often recrystallized making the systematic determination difficult. However, microgranular calcite walls seem to have resisted better the incipient neomorphism presented by the limestones of the Vaca Muerta Formation. Seven known species of Chitinoidellidae and four known species of Calpionellidae are recognized. The distribution of calpionellid species allows recognizing the Chitinoidella and Crassicollaria Zones in the Neuquén Basin. The Chitinoidella Zone correlates with the Virgatosphinctes mendozanus–Windhauseniceras internispinosum Andean ammonite Zones, and can be divided into two subzones. The lower one is poorly defined, while the upper one can be assigned to the Boneti Subzone. The Crassicollaria Zone in the Neuquén basin needs a detailed revision, but data provided in this work enable its correlation at least with the Corongoceras alternans ammonite Zone. Similar associations were reported in Mexico and Cuba, showing good consistency between these regions. However, in the Neuquén Basin unlike the Tethys, chitinoidellids persist until the lower Berriasian.
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Magnetostratigraphy of the Upper Jurassic–Lower Cretaceous from Argentina: Implications for the J-K boundary in the Neuquén Basin
Article
  • Feb 2017
A systematic sedimentologic and paleomagnetic study was carried out in the Vaca Muerta Formation, cropping out in the northern Neuquén Basin, west-central Argentina. The studied section is c.280 m-thick and represents a carbonate ramp system bearing ammonites that indicate Late Jurassic–Early Cretaceous ages. The Vaca Muerta Formation is one of the most important unconventional hydrocarbon reservoirs in the world and its thorough study has become a relevant target in Argentina. The J-K boundary is comprised within this unit, and although it is well-dated through biostratigraphy -mainly ammonites-, the position of particularly the boundary is yet a matter of hot debate. Therefore, the systematic paleomagnetic and cyclostratigraphic study in the Vaca Muerta Formation was considered relevant in order to obtain the first Upper Jurassic–Lower Cretaceous magnetostratigraphy of the southern hemisphere on the first place and to precise the position of the J-K boundary in the Neuquén Basin, on the other. Biostratigraphy is well studied in the area, so that paleomagnetic sampling horizons were reliably tied, particularly through ammonites. Almost 450 standard specimens have been processed for this study distributed along 56 paleomagnetic sampling horizons that were dated using ammonites. Paleomagnetic behaviours showed to be very stable, and their quality and primary origin have been proved through several paleomagnetic field tests The resultant magnetostratigraphic scale is made up of 11 reverse and 10 normal polarity zones, spanning the Andean Virgatosphinctes mendozanus (lower Tithonian) to Spiticeras damesi Zones (upper Berriasian). These polarity zones were correlated with those of the International Geomagnetic Polarity Time Scale 2012 and 2016 through the correlation between Andean and Tethyan ammonite zones. Cyclostratigraphy on the other hand, proved to be quite consistent with the magnetostratigraphy. Through the correlation of the resultant paleomagnetic and cyclostratigraphic data, it was possible to date the section with unprecedented precision, and therefore, to establish the position of the Jurassic-Cretaceous boundary. The paleomagnetic pole calculated from the primary magnetization is located at: Lon= 191.6°E, Lat= 76.2°S, A95= 3.5°, indicating a c. 24° clockwise rotation for the studied section, which is consistent with structural data of the region.
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