Biostratigraphy

Maastrichtian calcareous nannofossil biostratigraphy and paleoecology in the Equatorial Atlantic (Demerara Rise, ODP Leg 207 Hole 1258A)

by Nicolas Thibault

Thibault, N., Gardin, S., "published in 'Revue de Micropaléontologie', 2006, v. 49, p. 199-214"

Species richness, absolute and relative abundances of Maastrichtian calcareous nannofossils were analyzed in Hole... more Species richness, absolute and relative abundances of Maastrichtian calcareous nannofossils were analyzed in Hole 1258A. Absolute abundances
of taxa were used for the biozonation of this hole and the record of successive bio-events. Distribution patterns of cool water taxa such as
Ahmuellerella octoradiata, Gartnerago segmentatum and Kamptnerius magnificus underscore two major cooling events. These events occurred
during Chron C31r and during undifferentiated Chrons C31n to C30n. The latter event appears to be accompanied by lowered productivity, as
expressed by the lower abundances of fertility index taxa Biscutum constans and Zeugrhabdotus spp. An end-Maastrichtian warming event is
recorded in Chron C29r by the sudden drop in abundance of cool water taxa and acme of tropical taxon Micula murus. The disappearance of
B. constans just before this event and the significant increase of Micula decussata, respectively, suggest lowered productivity and high-stress
environmental conditions prior to the K/P boundary (Cretaceous–Paleogene). These results correlate very well with the climatic scenario proposed
by Li and Keller (1998a) in South Atlantic Hole 525A as suggested by stable isotopes and distribution patterns of planktic foraminifera.

Latitudinal migration of calcareous nannofossil Micula murus in the Maastrichtian: implications for global climate change

by Nicolas Thibault

Thibault, N., Gardin, S. and Galbrun, B., "published in 'Geology, 2010, v. 38, p. 203-206'"

Micula murus is one of the main calcareous nannofossil b iostratigrapic markers of Tethyan and Intermediate provinces... more Micula murus is one of the main calcareous nannofossil b iostratigrapic markers of Tethyan and Intermediate provinces in the upper Maastrichtian (uppermost Cretaceous). A review of its first occurrence at 14 deep-sea sites and sections shows that it is time transgressive from the Tropical Realm of the Atlantic and Pacific Oceans to the intermediate latitudes of the North Atlantic, South Atlantic, Indian Ocean and the northern Tethys. M. murus remained confined to the Tropical Realm for ~1.2 m.y. in the early late Maastrichtian, thus supporting high-latitudinal thermal gradients. It subsequently spread out in the late Maastrichtian to temperate latitudes and to the Tethys in coincidence with the onset of a thermohaline circulation change at ~67.5 Ma, suggesting a major change in surface-water circulation and interocean communications.

The cyclic Rørdal Member - a new lithostratigraphic unit of chronostratigraphic and palaeoclimatic importance in the upper Maastrichtian of Denmark

by Nicolas Thibault

Surlyk et al., 2010, published in Bulletin of the Geological Society of Denmark, Vol. 58, pp. 89-98.

The Maastrichtian chalk of the Danish Basin has been referred to the Tor Formation of the North Sea, but this may not... more The Maastrichtian chalk of the Danish Basin has been referred to the Tor Formation of the North Sea, but this may not be tenable because this formation in its type  area shows a much higher degree of redeposition than the Maastrichtian chalk of the Danish Basin. The onshore succession has not been lithostratigraphically subdivided due to its rather monotonous nature and the widely scattered outcrops. An exception is the uppermost Maastrichtian exposed at Stevns Klint which is been referred to the Sigerslev Member, comprising rather benthos-poor, deep-water pure chalk, and the overlying mound-bedded, bryozoan-rich chalk which is placed in the Højerup Member. In addition, a thin marly chalk bed, the Kjølby Gaard Marl Member, containing Tethyan planktonic foraminifers is known from localities in northern Jylland and from water wells around Køge, eastern Sjælland. The new Rørdal Member is a cyclic chalk-marl unit, about 10 m thick, sandwiched between pure white chalks. It is well exposed in the large Rørdal quarry in Aalborg, and is recognised in boreholes south of Aalborg and in the Stevns-1 and Karlslunde-1 boreholes south of Copenhagen. Coccolith and brachiopod data show that it belongs to the UC20b-cBP nannofossil zone of the North Sea scheme for the Upper Cretaceous Boreal province, and the semiglobularis-humboldtii brachiopod zone, both indicating the lower upper Maastrichtian. Isotope data show that it represents a distinct early late Maastrichtian cooling event. The member thus has a basinwide distribution and is an important isochronous marker because it represents a significant change in sea-water temperature and not a progradational event.

Upper Campanian - Maastrichtian nannofossil biostratigraphy and high-resolution carbon-isotope stratigraphy of the Danish Basin: towards a standard <delta>13C curve for the Boreal Realm

by Nicolas Thibault

Thibault, N. et al., in press in Cretaceous Research, doi:10.1016/j.cretres.2011.09.001

High-resolution carbon isotope stratigraphy of the upper Campanian – Maastrichtian is recorded in the Boreal Realm... more High-resolution carbon isotope stratigraphy of the upper Campanian – Maastrichtian is recorded in the Boreal Realm from a total of 1968 bulk chalk samples of the Stevns-1 core, eastern Denmark. Isotopic trends are calibrated by calcareous nannofossil bio-events and are correlated with a lower-resolution δ13C profile from Rørdal, northwestern Denmark. A quantitative approach is used to test the reliability of Upper Cretaceous nannofossil bio-events and provides accurate biohorizons for the correlation of δ13C profiles. The Campanian–Maastrichtian boundary (CMB) is identified through the correlation of dinoflagellate biostratigraphy and δ13C stratigraphy between Stevns-1 and the Global boundary Standard Stratotype-section and Point at Tercis les Bains (SW France), allowing the identification of new chemical and biostratigraphic markers that provide a precise placement of the stage boundary on a regional scale. The boundary interval corresponds to the third phase of a stepwise 0.8‰ negative δ13C excursion, lies in calcareous nannofossil subzone UC16dBP, and encompasses the last occurrence of nannofossil Tranolithus stemmerikii and first occurrence of nannofossil Prediscosphaera mgayae. Fifteen δ13C events are defined and correlated to sixteen reliable nannofossil biohorizons, thus providing a well-calibrated standard high-resolution δ13C curve for the Boreal Realm.

Bio-magnetochronology for the upper Campanian - Maastrichtian from the Gubbio area, Italy: new results from the Contessa Highway and Bottaccione sections

by Nicolas Thibault

Gardin, S., Galbrun, B., Thibault, N., Coccioni, R., Premoli Silva, I., Newsletter on Stratigraphy. In press. http://www.ingentaconnect.com/content/schweiz/nis/pre-prints/0014

A new bio-chronostratigraphic framework is presented for the upper Campanian-Maastrichtian pelagic sediments of the... more A new bio-chronostratigraphic framework is presented for the upper Campanian-Maastrichtian pelagic sediments of the Gubbio area (Bottaccione and Contessa Highway sections, Italy). New planktonic foraminiferal (FO of P. hantkeninoides), calcareous nannofossil (FO of M. prinsii, base acme of M. murus) and magnetostratigraphic data are provided and integrated to construct an age-depth curve based on the recent astronomical calibration of the late Campanian-Maastrichtian magnetic polarity time scale (Husson, D., Galbrun, B., Laskar, J., Hinnov, L.A., Thibault, N., Gardin, S., Locklair, R.E., 2011. Astronomical calibration of the Maastrichtian, Late Cretaceous. Earth and Planetary Science Letters 305, 328-340). All bio-horizons recorded in both sections fall on or are very close to the Line of Correlation (LOC), which testifies to the reliability of biochronologic studies in the Umbria-Marche basin. The proposed age model allows to estimate the sedimentation rates and the ages of calcareous nannofossil and planktonic foraminiferal bio-horizons in both sections. Also, it provides an excellent late Campanian–Maastrichtian reference for sections in the Umbria-Marche area and the entire southern Tethys. Due to the presence of a ~425 kyr-long hiatus in Chron C31n of the Bottaccione section, the Contessa Highway section constitutes a more complete late Campanian–Maastrichtian reference for bio-magnetochronology in the Tethyan realm.

Astronomical calibration of upper Campanian-Maastrichtian carbon isotope events and calcareous plankton biostratigraphy in the Indian Ocean (ODP Hole 762C): implication for the age of the Campanian-Maastrichtian boundary

by Nicolas Thibault

Thibault, N., Husson, D., Harlou, R., Gardin, S., Galbrun, B., Huret, E., Minoletti, F., Palaeo3. in press. http://www.sciencedirect.com/science/article/pii/S0031018212001769?v=s5

An integrated framework of magnetostratigraphy, calcareous microfossil bio-events, cyclostratigraphy and δ13C... more An integrated framework of magnetostratigraphy, calcareous microfossil bio-events, cyclostratigraphy and δ13C stratigraphy is established for the upper Campanian-Maastrichtian of ODP Hole 762C (Exmouth Plateau, Northwestern Australian margin). Bulk-carbonate δ13C events and nannofossil bio-events have been recorded and plotted against magnetostratigraphy, and provided absolute ages using the results of the cyclostratigraphic study and the recent astronomical calibration of the Maastrichtian. Fifteen carbon-isotope events and 40 nannofossil bio-events are recognized and calibrated with cyclostratigraphy, as well as 14 previously published foraminifer events, thus constituting a solid basis for large-scale correlations. Results show that this site is characterized by a nearly continuous sedimentation from the upper Campanian to the K-Pg boundary, except for a 500 kyr gap in magnetochron C31n. Correlation of the age-calibrated δ13C profile of ODP Hole 762C to the δ13C profile of the Tercis les Bains section, Global Stratotype Section and Point of the Campanian-Maastrichtian boundary (CMB), allowed a precise recognition and dating of this stage boundary at 72.15 Ma. Correlation of this boundary with the Lägerdorf - Kronsmoor - Hemmoor section shows that the CMB as defined at the GSSP is ~800 kyr younger than the CMB as defined by Belemnite zonation in the Boreal realm. ODP Hole 762C is the first section to bear at the same time an excellent recovery of sediments throughout the upper Campanian-Maastrichtian, a precise and well-defined magnetostratigraphy, a high-resolution record of carbon isotope events and calcareous plankton biostratigraphy, and a cyclostratigraphic study tied to the La2010 astronomical solution. This section is thus proposed as an excellent reference for the upper Campanian-Maastrichtian in the Indian Ocean.

Stratigraphie und Cephalopodenfauna des Unter-Apt von Alstätte (NRW)

by Rene Hoffmann

Aus dem Raum Alstätte (westliches Münsterland) wird ein neuer Tagesaufschluss, in dem Sedimente der
Unterkreide... more Aus dem Raum Alstätte (westliches Münsterland) wird ein neuer Tagesaufschluss, in dem Sedimente der
Unterkreide (Unter-Apt) anstehen, dokumentiert. Es wird die Litho- und Biostratigraphie, die Makrofauna,
die Sedimentologie, das Ablagerungsmilieu und die regionalgeologische Stellung dieses Aufschlusses
beschrieben. Ausgehend von einer lithofaziellen Profilaufnahme wird die Taxonomie und Biostratigraphie
der horizontiert entnommenen Ammoniten und Belemniten diskutiert. Die bearbeitete Schichtenfolge kann
der Ammonitenzone des Deshayesites tenuicostatus bzw. der Neohibolites ewaldi Belemnitenzone zugeordnet
werden. Ein 1,8m mächtiges Paket feinlaminierter Tonsteine, der Fischschiefer, entspricht dem
Oceanic Anoxic Event 1a (OAE 1a). Bemerkenswert ist ein Rostrum der tethyalen Belemnitenart Duvalia
grasiana, das 1m über dem Fischschiefer geborgen wurde; dieser Fund belegt eine frühaptzeitliche Immigration
tethyaler Faunen.

Foraminiferal biofacies and palaeoenvironmental evolution of an Oligo-Miocene cool-water carbonate succession in the Otway Basin, Southeast Australia

by Stephen Gallagher

The sedimentology and palaeoenvironments of the Late Cretaceous Sherbrook Group in the Otway Basin

by Stephen Gallagher

Revised stratigraphy of the Blanchetown Clay, Murray Basin: age constraints on the evolution of mega-lake Bungunnia

by Stephen Gallagher

Climate variability in the Late Cretaceous greenhouse world

by Stephen Gallagher

Biostratigraphy and macroinvertebrate palaeontology of the petroleum-rich Belfast Mudstone (Sherbrook Group, uppermost Turonian to mid-Santonian), Otway Basin, southeastern Australia

by Stephen Gallagher

A new subdivision of the Albian spore-pollen zonation of Australia

by Stephen Gallagher

Revised Oligo-Miocene stratigraphy of the Murray Basin, southeast Australia. Australian Journal of Earth Sciences

by Stephen Gallagher

A new Silurian microvertebrate assemblage from the Tortworth inlier, Avon, England

by Susan Turner

Turner, S. 2011. The Triassic Timescale. Many-sided time: review of S. G. Lucas ed. 2010. Geological Society Special Publication no. 334, London, 514 pp. Price £95. tag, Geol Soc Australia Newsletter no. 161, December, 39-40.

by Susan Turner

see information on the book on the Geological Society of London website

Reanalysis of "Raptorex kriegsteini": a juvenile tyrannosaurid dinosaur from Mongolia

by Denver Fowler

FOWLER, D.W., WOODWARD, H.N., FREEDMAN, E.A., LARSON, P.L., & HORNER, J.R. (2011) PLoS One 6(6): e21376. doi:10.1371/journal.pone.0021376

http://www.denverfowler.com/index.php?module=htmlpages&func=display&pid=43

The carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and... more The carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and massive robust skulls with laterally thickened teeth. The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the distinctive anatomical traits of derived tyrannosaurids were acquired in the Early Cretaceous, before the evolution of large body size. This inference depends on two core interpretations: that the holotype (LH PV18) derives from the Lower Cretaceous of China, and that despite its small size, it is a subadult or young adult. Here we show that the published data is equivocal regarding stratigraphic position and that ontogenetic reanalysis shows there is no reason to conclude that LH PV18 has reached this level of maturity. The probable juvenile status of LH PV18 makes its use as a holotype unreliable, since diagnostic features of Raptorex may be symptomatic of its immature status, rather than its actual phylogenetic position. These findings are consistent with the original sale description of LH PV18 as a juvenile Tarbosaurus from the Upper Cretaceous of Mongolia. Consequently, we suggest that there is currently no evidence to support the conclusion that tyrannosaurid skeletal design first evolved in the Early Cretaceous at small body size.

No definitive evidence of Paleocene dinosaurs in the San Juan Basin

by Denver Fowler

LUCAS, S.G, SULLIVAN, R.M., CATHER, S.M., JASINSKI, S.E, FOWLER, D.W., HECKERT, A.B., SPIELMANN, J.A, & HUNT, A.P. (2009) Paleontologica electronica, 12(2); 8A: 10p.

In a recent article in this journal, Fassett (2009) concludes that dinosaur fossils of Paleocene age are present in... more In a recent article in this journal, Fassett (2009) concludes that dinosaur fossils of Paleocene age are present in the San Juan Basin of New Mexico-Colorado. However, we argue that, based on existing data, Fassett has failed to produce compelling evidence to support this conclusion. In the San Juan Basin, only one arguably reworked dinosaur bone (an isolated hadrosaur femur) is stratigraphically above undisputed Paleocene pollen, so palynology does not demonstrate Paleocene dinosaurs in the San Juan Basin. Nor does magnetostratigraphy, because Fassett’s disregard of a major unconformity above the dinosaur-bearing Naashoibito Member renders questionable his use of an uninterrupted magnetostratigraphy to assign a Paleocene age to dinosaur fossils in that unit. Moreover, Fassett’s article failed to adequately dismiss the broadly held conclusions that: (1) the Cretaceous-Tertiary boundary is within the Ojo Alamo Sandstone; (2) the dinosaur-dominated vertebrate fossil assemblage of the lower Ojo Alamo Sandstone (Alamo Wash local fauna of the Naashoibito Member) is of Maastrichtian age; and (3) the isolated, water-worn and/or fragmentary dinosaur bones from the overlying Kimbeto Member are reworked from underlying Cretaceous strata.

Early Cretaceous megaspore assemblages from southeastern Australia

by Stephen McLoughlin

Reference:
Tosolini, A.-M., McLoughlin, S. & Drinnan, A.N. 2002. Early Cretaceous megaspore assemblages from southeastern Australia. Cretaceous Research, 23: 807-844.

Twenty-nine megaspore species including six new taxa (Bacutriletes otwayensis sp. nov., Erlansonisporites cerebrus sp.... more Twenty-nine megaspore species including six new taxa (Bacutriletes otwayensis sp. nov., Erlansonisporites cerebrus sp. nov., Erlansonisporites decisum sp. nov., Hughesisporites coronatus sp. nov., Hughesisporites dettmanniae sp. nov., and Verrutriletes depressus sp. nov.) are documented from Aptian and Albian strata of the Gippsland and Otway basins, southeastern Australia. Together with six taxa known only from underlying Neocomian strata, these megaspores are used to establish four provisional biozones for the Lower Cretaceous that complement existing biostratigraphic schemes based on miospores and plant macrofossils. Megaspores are best represented in silty floodbasin facies and it is likely that the parent plants predominantly occupied moist understorey to fully aquatic habitats on the floodplain. Megaspores are sparsely represented in most other fluvial facies chiefly due to reworking of floodbasin sediments into higher energy channel and crevasse deposits. The relatively high diversity of lycophyte and fern megaspores contrasts with the scarcity of these plant groups in macrofossil assemblages. The megaspore record suggests that heterosporous cryptogams may have been significantly more prominent in the vegetation of this region than previously suggested. Several megaspores from southeastern Australia are closely comparable to forms from India and Argentina indicating broad similarities between Early Cretaceous heterosporous fern and lycophyte communities across Gondwana. These similarities also suggest that megaspores may be useful for inter-continental biostratigraphic correlation.

Late Permian plant megafossils from the Bowen Basin, Queensland, Australia: Part 3

by Stephen McLoughlin

Reference:
McLoughlin, S. 1994. Late Permian plant megafossils from the Bowen Basin, Queensland, Australia: Part 3. Palaeontographica 231B: 31-62.

Glossopterid gymnosperms dominate the Late Permian floras of the Bowen Basin, Queensland, Australia. Seven new species... more Glossopterid gymnosperms dominate the Late Permian floras of the Bowen Basin, Queensland, Australia. Seven new species of Glosopteris (viz., G. indicoides, G. kingii, G. linguiforma, G. plumata, G. rhombimaculata, G. truncata, and G. xiphophylla) are described together with G. rectinervis Dun 1897 emend. Banerjee 1978 and a form comparable to the Antarctic G. schopfii Pigg 1990. Analysis of the distribution of 62 megaplant species recorded from 11 lithological units in the southern Bowen Basin offers the potential for improved phytostratigraphic zonation of the Australian Permian. The megaplant assemblages of the upper Blenheim Subgroup (Back Creek Group) and Blackwater Group, Bowen Basin, are correlated with the floras of the Tomago and Newcastle Coal Measures and their equivalents in the Sydney Basin. Few glossopterid species are shared among the Bowen Basin and extra-Australian basins. The studied megafloras show best intercontinental correlation (via shared glossopterid genera and sphenophyte species) with the Raniganj and Kamthi Formations, India, and Estcourt Formation, South Africa.