Suchergebnisse

Intro -- Half-Title -- Dedication -- Title -- Contents -- Prologue -- Chapter 1: The Eye-opener -- Chapter 2: Stolen Dreams -- Chapter 3: Crossover to Road -- Chapter 4: The Bloody Secret to Speed -- Chapter 5: The Lion Meets the Pussy Cat -- Chapter 6: The Race of Truth -- Chapter 7: Go and Go Again… -- Chapter 8: Fuelling Dreams -- Chapter 9: Suffocating Stamina -- Chapter 10: Preparing to Peak (or Pass Out) -- Chapter 11: Exorcism at the Étape -- Chapter 12: The Debrief -- References -- Acknowledgements -- Appendix 1: Training notes -- Appendix 2: Pro rider's race calendar -- Copyright.

This project has received funding from the National Science foundation (EAR 1455258 to C.K.J), the European Research Council under the European Union's Horizon 2020 research and innovation programme (Grant 678812 to M.W.C.) and a University of St Andrews Global Fellowship (to C.K.J.). ; Sulfate aerosols have long been implicated as a primary forcing agent of climate change and mass extinction in the aftermath of the end-Cretaceous Chicxulub bolide impact. However, uncertainty remains regarding the quantity, residence time, and degree to which impact-derived sulfur transited the stratosphere, where its climatic impact would have been maximized. Here, we present evidence of mass-independent fractionation of sulfur isotopes (S-MIF) preserved in Chicxulub impact ejecta materials deposited in a marine environment in the Gulf Coastal Plain of North America. The mass anomalous sulfur is present in Cretaceous–Paleogene event deposits but also extends into Early Paleogene sediments. These measurements cannot be explained by mass conservation effects or thermochemical sulfate reduction and therefore require sulfur-bearing gases in an atmosphere substantially different from the modern. Our data cannot discriminate between potential source reaction(s) that produced the S-MIF, but stratospheric photolysis of SO2 derived from the target rock or carbonyl sulfide produced by biomass burning are the most parsimonious explanations. Given that the ultimate fate of both of these gases is oxidation to sulfate aerosols, our data provide direct evidence for a long hypothesized primary role for sulfate aerosols in the postimpact winter and global mass extinction. ; Publisher PDF ; Peer reviewed