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Badger M.P.S.,University of Bristol | Lear C.H.,University of Bristol | Pancost R.D.,University of Bristol | Foster G.L.,University of Bristol | And 5 more authors.
Paleoceanography | Year: 2013

The development of a permanent, stable ice sheet in East Antarctica happened during the middle Miocene, about 14 million years (Myr) ago. The middle Miocene therefore represents one of the distinct phases of rapid change in the transition from the "greenhouse" of the early Eocene to the "icehouse" of the present day. Carbonate carbon isotope records of the period immediately following the main stage of ice sheet development reveal a major perturbation in the carbon system, represented by the positive δ13C excursion known as carbon maximum 6 ("CM6"), which has traditionally been interpreted as reflecting increased burial of organic matter and atmospheric pCO2 drawdown. More recently, it has been suggested that the δ13C excursion records a negative feedback resulting from the reduction of silicate weathering and an increase in atmospheric pCO2. Here we present high-resolution multi-proxy (alkenone carbon and foraminiferal boron isotope) records of atmospheric carbon dioxide and sea surface temperature across CM6. Similar to previously published records spanning this interval, our records document a world of generally low (~300 ppm) atmospheric pCO2 at a time generally accepted to be much warmer than today. Crucially, they also reveal a pCO2 decrease with associated cooling, which demonstrates that the carbon burial hypothesis for CM6 is feasible and could have acted as a positive feedback on global cooling. © 2013. American Geophysical Union. All Rights Reserved.

Dimitrova T.K.,Bulgarian Academy of Science | Zodrow E.L.,Cape Breton University | Cleal C.J.,Amgueddfa Cymru National Museum Wales | Thomas B.A.,Aberystwyth University
Geological Journal | Year: 2010

The palynology of clastic samples from seven stratigraphical levels in the late Moscovian Sydney Mines Formation, exposed along the shore at Bras d'Or, Nova Scotia, has been investigated. Most of the samples were from roof shales of major coals; the one sample that was not yielded a much higher proportion of pollen derived from extra-basinal vegetation. The four stratigraphically lower roof shale samples yielded essentially similar palynological spectra, with 39±4% lycophytes, 9±4% sphenophylls, 23±4% tree-ferns, 12±4% other ferns and 5±3% cordaites. The palynology of the upper part of the investigated succession suggests a shift in vegetation towards one favouring more marattialean treeferns, cordaites and conifers, and fewer lycophytes. This correlates with changes in drainage patterns as the alluvial plain migrated seawards and thus changed water tables. No evidence was found to suggest significant climate change at this time. © 2009 John Wiley & Sons, Ltd.

Cleal C.J.,Amgueddfa Cymru National Museum Wales | Thomas B.A.,Aberystwyth University
Taxon | Year: 2010

The provisions in the Code for naming plant fossil taxa have changed substantially over the years. The history of these changes reflects the tension between palaeobotanists (including palynologists studying plant microfossils) who need a flexible set of regulations, and the tendency for the Code to include nomenclatural regulations that constrain taxonomic decisions. The current Vienna Code now provides for plant fossils to be named as fossil taxa, which is a flexible taxonomic concept that should suit the needs of most palaeobotanists. However, the Vienna Code also incorporates the more restrictive concept of morphotaxa and most palaeobotanists seem to be under the misapprehension that plant fossils can only be named as morphotaxa. In our view, the concept of morphotaxa is logically flawed and unnecessary in practice, and should be removed from the Code.

Martill D.M.,University of Portsmouth | Vidovic S.U.,University of Portsmouth | Howells C.,Amgueddfa Cymru National Museum Wales | Nudds J.R.,University of Manchester
PLoS ONE | Year: 2016

Approximately 40% of a skeleton including cranial and postcranial remains representing a new genus and species of basal neotheropod dinosaur is described. It was collected from fallen blocks from a sea cliff that exposes Late Triassic and Early Jurassic marine and quasi marine strata on the south Wales coast near the city of Cardiff. Matrix comparisons indicate that the specimen is from the lithological Jurassic part of the sequence, below the first occurrence of the index ammonite Psiloceras planorbis and above the last occurrence of the Rhaetian conodont Chirodella verecunda. Associated fauna of echinoderms and bivalves indicate that the specimen had drifted out to sea, presumably from the nearby Welsh Massif and associated islands (St David's Archipelago). Its occurrence close to the base of the Blue Lias Formation (Lower Jurassic, Hettangian) makes it the oldest known Jurassic dinosaur and it represents the first dinosaur skeleton from the Jurassic of Wales. A cladistic analysis indicates basal neotheropodan affinities, but the specimen retains plesiomorphic characters which it shares with Tawa and Daemonosaurus. © 2016 Martill et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Ernst A.,University of Kiel | Buttler C.,Amgueddfa Cymru National Museum Wales
Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen | Year: 2012

Ten bryozoan species belonging to the Order Cystoporata are described from the Lower Devonian of the Cantabrian Mountains, NW Spain. Three genera, with one species respectively, are new: Physallidopora cantabrica gen. nov. sp. nov., Dolichozoon ramosum gen. nov. sp. nov. and Hiberotrypa dubia gen. nov. sp. nov. Two additional species are new: Fistuliporidra triangulata sp. nov. and Fistuliporidra hibera sp. nov. The studied fauna shows palaeobiogeographic relations to the Czech Republic, Germany, Poland and North America. © 2012 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.

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