Climate instability and tipping points in the Late Devonian: Detection of the Hangenberg Event in an open oceanic island arc in the Central Asian Orogenic Belt

0461368 - GLÚ 2017 RIV NL eng J - Článek v odborném periodiku
Carmichael, A. - Waters, J. A. - Batchelor, C. J. - Coleman, D. M. - Suttner, T. J. - Kido, E. - Moore, L. M. - Chadimová, Leona
Climate instability and tipping points in the Late Devonian: Detection of the Hangenberg Event in an open oceanic island arc in the Central Asian Orogenic Belt.
Gondwana Research. Roč. 32, 1 April (2016), s. 213-231. ISSN 1342-937X. E-ISSN 1878-0571
Institucionální podpora: RVO:67985831
Klíčová slova: Central Asian Orogenic Belt * chemostratigraphy * Devonian-Carboniferous * Hangenberg Event * West Junggar
Kód oboru RIV: DB - Geologie a mineralogie
Impakt faktor: 6.959, rok: 2016

Sedimentary petrology and trace element geochemistry indicate that the Late Devonian to Early Carboniferous Heishantou Formation near Boulongour Reservoir (NW Xinjiang, China) was deposited on a steep slope, mid-latitude accreting island arc complex in an open oceanic system. Bulk ⁸⁷Sr/⁸⁶Sr ratios show excursion patterns that are consistent with excursions at the Devonian-Carboniferous (D-C) boundary in epicontinental margin sediments. Sedimentation rates for the Boulongour Reservoir sediments show highly variable rates that range from 0.5 cm/ky to 10 cm/ky, consistent with other Late Devonian sections and modern arc environments. Multiple whole rock geochemical proxies for anoxia and the size and distribution of pyrite framboids suggest the presence of the Hangenberg Event in the sediments associated with the D-C boundary, despite the lack of visible black shale. The presence of anoxia in an open ocean, island arc environment cannot be explained by upwelling of anoxic bottom waters at this paleolatitude, but can be explained by the global infliction of oceanic shallow water eutrophication on to a climate system in distress.
Trvalý link: http://hdl.handle.net/11104/0260975