Evidence for global cooling in the Late Cretaceous.

The Late Cretaceous ‘greenhouse’ world witnessed a transition from one of the warmest climates of the past 140 million years to cooler conditions, yet still without significant continental ice. Low-latitude sea surface temperature (SST) records are a vital piece of evidence required to unravel the cause of Late Cretaceous cooling, but high-quality data remain illusive. Here, using an organic geochemical palaeothermometer (TEX86), we present a record of SSTs for the Campanian–Maastrichtian interval (~83–66¿Ma) from hemipelagic sediments deposited on the western North Atlantic shelf. Our record reveals that the North Atlantic at 35¿°N was relatively warm in the earliest Campanian, with maximum SSTs of ~35¿°C, but experienced significant cooling (~7¿°C) after this to <~28¿°C during the Maastrichtian. The overall stratigraphic trend is remarkably similar to records of high-latitude SSTs and bottom-water temperatures, suggesting that the cooling pattern was global rather than regional and, therefore, driven predominantly by declining atmospheric pCO2 levels

Pforams@microtax : Anew online taxonomic database for planktonic foraminifera

A new relational taxonomic database for planktonic foraminifera (\u201cpforams@mikrotax\u201d) has been constructed and is now freely available online at http://www.mikrotax.org. It represents amajor advance from its predecessor, the CHRONOS online taxonomic database, which has served the research community since 2005. The benefits of the new database to the research and industrial biostratigraphic communities are many, as it will serve as an immediately accessible taxonomic guide and reference for specialists and non-specialists alike by providing access to a wealth of information and images from original authors and from expertswho have inserted recent authoritative updates to planktonic foraminiferal taxonomy, phylogeny and biostratigraphy. The database will be continually updated and used as a guide for training current and future generations of students and professionals who will be able to self-educate on planktonic foraminiferal taxonomy and biostratigraphy. Further investigation of species traditionally included in the Cretaceous genera Heterohelix, Globigerinelloides, Marginotruncana, and Globotruncana is required to exclude the use of polyphyletic morphotaxa. The taxonomy for Paleogene planktonic foraminifera is quite stable following publication of the Paleocene, Eocene, and Oligocene taxonomic atlases, but revisions to the taxonomy and phylogeny of Neogene taxa are needed to incorporate results from genetic sequencing studies and recent biostratigraphic observations

Magnetobiostratigraphic Synthesis of Leg 123: Sites 765 and 766 (Argo Abyssal Plain and Lower Exmouth Plateau)

During ODP Leg 123, Sites 765 and 766 were drilled to examine the tectonic evolution, sedimentary history, and paleoceanography of the Argo Abyssal Plain and lower Exmouth Plateau. At each site, the quality of magnetostratigraphic and biostratigraphic records varies because of complicating factors, such as the predominance of turbidites, the presence of condensed horizons, or deposition beneath the CCD. Based primarily on the presence of nannofossils, the base of the sedimentary section at Site 765 was dated as Tithonian. A complete Cretaceous sequence was recovered at this site, although the sedimentation rate varies markedly through the section. The Cretaceous/Tertiary boundary is represented by a condensed horizon. The condensed Cenozoic sequence at Site 765 extends from the upper Paleocene to the lower Miocene. A dramatic increase in sedimentation rate was observed in the lower Miocene, and a 480-m-thick Neogene section is present. The Neogene section is continuous, except for a minor hiatus in the lower Pliocene. The base of the sedimentary section at Site 766 is Valanginian, in agreement with the site's position on marine magnetic anomaly Mil. Valanginian to Barremian sediments are terrigenous, with variable preservation of microfossils, and younger sediments are pelagic, with abundant well-preserved microfossils. Sedimentation rate is highest in the Lower Cretaceous and decreases continually upsection. Upper Cenozoic sediments are condensed, with several hiatuses

The role of cytokine gene polymorphisms in the pathogenesis of abdominal aortic aneurysms: A case-control study

AbstractBackground: Cytokines are the primary mediators of inflammation and also influence matrix metalloproteinase expression, both of which are important in development of abdominal aortic aneurysm (AAA). A significant, but as yet unknown, familial factor contributes to the pathogenesis of AAA. Many cytokine genes contain polymorphic sites, some of which affect cytokine production in vitro. Cytokine gene polymorphisms may therefore influence the pathogenesis of AAA. The purpose of this study was to determine whether there is any association between cytokine gene polymorphisms and AAA. Methods and Results: This case-control study comprised 100 patients with AAA and 100 age-matched and sex-matched control subjects. For each case and control subject in the study, genotypes at the following cytokine gene polymorphic loci were determined: interleukin (IL)-1β +3953, IL-6 −174, IL-10 −1082, IL-10 −592, and tumor necrosis factors-α −308. Allele and genotype frequencies were compared between AAA and control groups, and odds ratios (OR) were calculated for the presence of AAA with each allele at each locus examined as risk factors. The IL-10 −1082 A allele was significantly more common in the AAA group than the control group (P =.03). The OR for the IL-10 −1082 A allele as a risk factor for AAA was 1.8 (95% confidence interval, 0.9-3.6). Discussion: These associations suggest a significant role for IL-10 in the pathogenesis of AAA. This association of AAA with the IL-10 −1082 A allele is also biologically plausible; the IL-10 −1082 A allele is associated with low IL-10 secretion, and it may be that AAA develops in patients who are unable to mount the same anti-inflammatory response as those who do not have AAA. (J Vasc Surg 2003;37:999-1005.

Taxonomy, evolution and biostratigraphy of Late Triassic-Early Jurassic calcareous nannofossils

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