A refugium for charophytes during the maximum post-Palaeozoic sea-level highstand in the Turonian of Tarragona (Catalonia, Spain)

The oceanic anoxic event at the Cenomanian–Turonian transition (OAE-2) is a worldwide phenomenon related with variations in atmosphere–ocean dynamics. This event coincides with significant changes in the palaeoenvironment determining marine mass extinction affecting numerous groups of organisms. Ichnological analysis of the Cenomanian–Turonian boundary interval has been conducted in three selected sections from different ecological and depositional settings in the western Tethys. Indeed, a brief overview of existing knowledge in this domain highlights increasing recognition of the usefulness of trace fossils in the characterization of even minor-scale deep-sea environmental changes linked to sea-level dynamics. At the study sites, variations in ichnological features, including trace fossil composition, tiering patterns and ichnofabrics, can be related to fluctuations in bottom- and pore-water oxygenation during the Cenomanian–Turonian interval. In the Barnasiowka section (Polish Outer Carpathians), changes between oxic/dysoxic—characterized by Chondrites, Planolites and even Thalassinoides—and euxinic conditions, without trace fossils or only with Chondrites, can be explained by variations in gravity flows influencing the benthic habitat. In the El Chorro and Hedionda sections (Betic Cordillera), longer anoxic intervals during the OAE-2, characterized by the absence of trace fossils, are interrupted by shorter dysaerobic and aerobic sub-events associated with Chondrites, Palaeophycus, Planolites, Thalassinoides, Trichichnus and Zoophycos, but showing significant differences between these two sections related to the palaeogeographically differentiated influence of upwelling conditions.

The Kapanboğazı formation: A key unit for understanding Late Cretaceous evolution of the Pontides, N Turkey

The Cenomanian–Turonian boundary mass extinction (Late Cretaceous): New insights from ammonoid biodiversity patterns of Europe, Tunisia and the Western Interior (North America)

Fletcher, T.L. & Salisbury, S.W., XX.XX. 2014. Probable oribatid mite (Acari: Oribatida) tunnels and faecal pellets in silicified conifer wood from the Upper Cretaceous (Cenomanian–Turonian) portion of the Winton Formation, central-western Queensland, Australia. Alcheringa 38, 541–545. ISSN 0311-5518.Tunnels and faecal pellets likely made by oribatid mites have been found in silicified conifer wood from the Upper Cretaceous (Cenomanian–Turonian) portion of the Winton Formation, central-western Queensland, Australia. Although this is the first identified and described record of oribatid mites in the Mesozoic of Australia, other published, but unassigned material may also be referable to Oribatida. Current understanding of the climatic significance of mite distribution is limited, but the presence of oribatids and absence of xylophagus insects in the upper portion of the Winton Formation are consistent with indications that the environment in which this unit was deposited was relatively warm and wet for its palaeolatitude. Such traces may provide useful and durable proxy evidence of palaeoclimate, but more detailed investigation of modern taxa and their relationship to climate is still needed.Tamara L. Fletcher [t.fletcher1@uq.edu.au] and Steven. W. Salisbury, [s.salisbury@uq.edu.au] School of Biological Sciences, The University of Queensland, Australia, 4072. Received 28.1.2014; revised 1.4.2014; accepted 3.4.2014.

Recent exploration in the Faeroe–Shetland Basin has concentrated on the Paleocene, following the successes of the Foinaven and Schiehallion fields. However, a number of deeper Mesozoic plays may still exist in the basin. This paper describes results of recent exploration activity targeted at a Turonian play in the Faeroe–Shetland Basin, west of the Rona Ridge, and discusses implications for future prospectivity in the area. The play tested is a slope fan pinchout against the Rona Ridge, comprising Cenomanian–Turonian high density turbidite sandstones. These were shed into a deep-water basin in the hanging wall of the Rona Fault during a base-level change in the adjacent West Shetland Basin. Two wells have proven considerable thicknesses of interbedded sandstones and shales in the Cenomanian–Turonian interval. Reservoir quality is locally excellent with porosities exceeding 20% and permeabilities up to 1 D. While hydrocarbon shows have been encountered, targeted prospects appear to have failed because of a lack of up-dip seal, emphasizing that the key risk for down-thrown plays against the Rona Fault remains trap integrity. The presence of both oil and gas shows though, confirms that the Turonian sandstone package has acted as a migration focus and may represent the main conduit from the deeper Jurassic source kitchen into the Clair Field. A sedimentological and diagenetic model for the sandstones based on recently acquired core data implies that clean, high quality deposits may also exist in a more basinward setting, possibly as detached fan complexes. This stratigraphic interval remains a potential play for future exploration, but with the depth of burial increasing rapidly westwards, overpressuring may be required to preserve porosity and permeability.

Geographically different oceanographic responses to global warming during the Cenomanian–Turonian interval and Oceanic Anoxic Event 2

Early Cretaceous Mesochara-rich assemblages from central Patagonia, Argentina, predate the origin of homogenous Charoidean floras by about 30 million years

It is well established that greenhouse conditions prevailed during the Cretaceous Period (~145–66Ma). Determining the exact nature of the greenhouse-gas forcing, climatic warming and climate sensitivity remains, however, an active topic of research. Quantitative and qualitative geochemical and palaeontological proxies provide valuable observational constraints on Cretaceous climate. In particular, reconstructions of Cretaceous sea-surface temperatures (SSTs) have been revolutionised firstly by the recognition that clay-rich sequences can host exceptionally preserved planktonic foraminifera allowing for reliable oxygen-isotope analyses and, secondly by the development of the organic palaeothermometer TEX86, based on the distribution of marine archaeal membrane lipids. Here we provide a new compilation and synthesis of available planktonic foraminiferal δ18O (δ18Opl) and TEX86-SST proxy data for almost the entire Cretaceous Period. The compilation uses SSTs recalculated from published raw data, allowing examination of the sensitivity of each proxy to the calculation method (e.g., choice of calibration) and places all data on a common timescale. Overall, the compilation shows many similarities with trends present in individual records of Cretaceous climate change. For example, both SST proxies and benthic foraminiferal δ18O records indicate maximum warmth in the Cenomanian–Turonian interval. Our reconstruction of the evolution of latitudinal temperature gradients (low, <±30°, minus higher, >±48°, palaeolatitudes) reveals temporal changes. In the Valanginian–Aptian, the low-to-higher mid-latitudinal temperature gradient was weak (decreasing from ~10–17°C in the Valanginian, to ~3–5°C in the Aptian, based on TEX86-SSTs). In the Cenomanian–Santonian, reconstructed latitudinal temperature contrasts are also small relative to modern (<14°C, based on low-latitude TEX86 and δ18Opl SSTs minus higher latitude δ18Opl SSTs, compared with ~20°C for the modern). In the mid-Campanian to end-Maastrichtian, latitudinal temperature gradients strengthened (~19–21°C, based on low-latitude TEX86 and δ18Opl SSTs minus higher latitude δ18Opl SSTs), with cooling occurring at low-, middle- and higher palaeolatitude sites, implying global surface-ocean cooling and/or changes in ocean heat transport in the Late Cretaceous. These reconstructed long-term trends are resilient, regardless of the choice of proxy (TEX86 or δ18Opl) or calibration. This new Cretaceous SST synthesis provides an up-to-date target for modelling studies investigating the mechanics of extreme climates.

Polycotylidae is a clade of plesiosaurians that appeared during the Early Cretaceous and became speciose and abundant early in the Late Cretaceous. However, this radiation is poorly understood. Thililua longicollis from the Middle Turonian of Morocco is an enigmatic taxon possessing an atypically long neck and, as originally reported, a series of unusual cranial features that cause unstable phylogenetic relationships for polycotylids. We reinterpret the holotype specimen of Thililua longicollis and clarify its cranial anatomy. Thililua longicollis possesses an extensive, foramina-bearing jugal, a premaxilla–parietal contact and carinated teeth. Phylogenetic analyses of a new cladistic dataset based on first-hand observation of most polycotylids recover Thililua and Mauriciosaurus as successive lineages at the base of the earliest Late Cretaceous polycotyline radiation. A new dataset summarizing the Bauplan of polycotylids reveals that their radiation produced an early burst of disparity during the Cenomanian–Turonian interval, with marked plasticity in relative neck length, but this did not arise as an ecological release following the extinction of ichthyosaurs and pliosaurids. This disparity vanished during and after the Turonian, which is consistent with a model of ‘early experimentation/late constraint’. Two polycotylid clades, Occultonectia clade nov. and Polycotylinae, survived up to the Maastrichtian, but with low diversity.

A spiny lobster, genus and species undetermined (Palinuridae Latreille, 1802) from the Upper Cretaceous (Cenomanian–Turonian) of Gara Sbaa (southeastern Morocco, NW Africa), is herein described. This is the second fossil record for a palinurid from Africa, enlarging the knowledge on the worldwide distribution of the family.

The Cenomanian–Turonian (Upper Cretaceous) Galala and Maghra el Hadida formations of the Southern Galala Plateau in Wadi Araba (northern Eastern Desert, Egypt) represent marine depositional systems developing in response to the early Late Cretaceous transgression at the southern margin of the Neotethyan Ocean in tropical paleolatitudes. A facies analysis (litho-, bio- and microfacies) of these successions shows the presence of 22 facies types (FTs, six are related to the Galala Formation, while the Maghra el Hadida Formation is represented by 16 FTs). The Galala Formation was deposited in a fully marine lagoonal environment developing in response to a latest Middle to early Late Cenomanian transgression. The rich suspension- and deposit-feeding macrobenthos of the Galala Formation indicate meso- to eutrophic (i.e., green water) conditions. The facies types of the uppermost Cenomanian–Turonian Maghra el Hadida Formation suggest deposition on a homoclinal carbonate ramp with sub-environments ranging from deep-subtidal basin to intertidal back-ramp. Major and rapid shifts in depositional environments, related to (relative) sea-level changes, occurred in the mid-Late Cenomanian, the Early–Middle Turonian boundary interval, the middle part of the Middle Turonian and the Middle–Late Turonian boundary interval.

Upper Cretaceous (Cenomanian–Turonian) formations in the Kyzylkum Desert of Uzbekistan, especially the Bissekty Formation at Dzharakuduk, have yielded a great diversity of continental vertebrates, including dinosaurs. Underwater screening of the sandy matrix has recovered many dinosaurian teeth. Here we describe and illustrate two types of enigmatic theropod teeth that are referable to Paronychodon and Richardoestesia, respectively. Both of these tooth taxa are well known from the Late Cretaceous of North America and possibly represent stages in the development of the teeth of various paravian theropods. Confirmation of this hypothesis awaits discovery of more complete jaws.

A new limulid (Chelicerata, Xiphosurida) from the Late Cretaceous (Cenomanian–Turonian) of Gara Sbaa, southeast Morocco

Late Cretaceous and Cenozoic Vegetation in China, Emphasizing Their Connections With North America

The formation of oceanic plateaus in the Pacific in the Mesozoic has been proposed to create major environmental impacts, including global anoxic events OAE-1 in the Aptian (ca. 120 Ma) and OAE-2 in the Cenomanian–Turonian (ca. 90 Ma). However, our understanding of the formation of these large volcanic systems and their environmental effects are strongly limited by difficulties in accessing them and characterising their volcanic evolution. In particular, it remains significant to determine whether Pacific oceanic plateaus experience a phase of subaerial volcanic activity as this has critical implications in terms of their environmental impacts. Herein we provide the first unequivocal evidence for an emergent volcanic phase of the Caribbean oceanic plateau in the Late Cretaceous. This subaerial phase is evidenced by accreted oceanic sequences in Colombia that include fallout tuffs with accretionary lapilli and lahar deposits. This facies assemblage, recognised for the first time in an oceanic plateau, reflects phreatomagmatic eruptions coeval with subaerial erosion on an oceanic island. This result, combined with previous evidence of subaerial development of the Ontong Java Plateau and Shatsky Rise, suggests that syn-volcanic emergence of oceanic plateaus was common in the Pacific during the Mesozoic. Although temporal and spatial scales of these emergences remain poorly constrained it confirms that emergence of the Caribbean plateau in the Late Cretaceous (ca. 90 Ma) could have actively contributed to atmospheric changes and the establishment of OAE-2. Significantly, emergence of the Caribbean plateau occurred synchronously to the beginning of its tectonic displacement between the Americas. We propose that this unusual volcanic and tectonic evolution led to drastic reduction of the flow of Pacific oxygenated bottom waters into the early Atlantic basin, leading to a series of regional anoxic events previously documented between the Coniacian and Santonian (OAE-3, ca. 89 to 84 Ma). In addition, emergence of the Caribbean Plateau in the early inter-American seaway could have facilitated migration of terrestrial organisms between the Americas in the Late Cretaceous. The formation of the Caribbean plateau had therefore a large range of possible environmental effects, from atmospheric to palaeo-oceanographic and biotic impacts.