Evidence for weathering and volcanism during the PETM from Arctic Ocean and Peri-Tethys osmium isotope records

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doi: 10.1016/j.palaeo.2015.08.019
Author(s): Dickson, Alexander J.; Cohen, Anthony S.; Coe, Angela L.; Davies, Marc; Shcherbinina, Ekaterina A.; Gavrilov, Yuri O.
Author Affiliation(s): Primary:
Open University, Department of Environment, Earth and Ecosystems, Milton Keynes, United Kingdom
Russian Academy of Sciences, Geological Institute, Russian Federation
Volume Title: Palaeogeography, Palaeoclimatology, Palaeoecology
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Vol.438, p.300-307. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. 71 refs.; illus., incl. sketch map
Summary: Sudden global warming during the Paleocene-Eocene Thermal Maximum (PETM, 55.9 Ma) occurred because of the rapid release of several thousand gigatonnes of isotopically light carbon into the oceans and atmosphere; however, the cause of this release is not well understood. Some studies have linked carbon injection to volcanic activity associated with the North Atlantic Igneous Province (NAIP), while others have emphasized carbon cycle feedbacks associated with orbital forcing. This study presents the osmium isotope compositions of mudrocks that were deposited during the PETM at four locations (one from the Arctic Ocean, and three from the Peri-Tethys). The Os-isotope records all exhibit a shift of similar magnitude towards relatively radiogenic values across the PETM. This observation confirms that there was a transient, global increase in the flux of radiogenic Os from the weathering of continental rocks in response to elevated temperatures at that time. The tectonic effects of NAIP volcanic emplacement near the onset of the PETM is recorded by anomalously radiogenic Os-isotope compositions of PETM-age Arctic Ocean samples, which indicate an interval of hydrographic restriction that can be linked tectonic uplift due to hotspot volcanism in the North Atlantic seaway. The Peri-Tethys data also document a transient, higher flux of unradiogenic osmium into the ocean near the beginning of the PETM, most likely from the weathering of young mafic rocks associated with the NAIP. These observations support the hypothesis that volcanism played a major role in triggering the cascade of environmental changes during the PETM, and highlight the influence of paleogeography on the Os isotope characteristics of marine water masses. Abstract Copyright (2015) Elsevier, B.V.
Year of Publication: 2015
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Arctic Coring EXpedition; Arctic Ocean; Asia; Atlantic Ocean; Basque Provinces Spain; Cenozoic; Commonwealth of Independent States; DSDP Site 213; DSDP Site 549; Dagestan Russian Federation; Deep Sea Drilling Project; Dzhengutay Russian Federation; Europe; Expedition 302; Guru-Fatima Tajikistan; IODP Site M0004; IPOD; Iberian Peninsula; Indian Ocean; Integrated Ocean Drilling Program; Isotope ratios; Isotopes; Kabardin-Balkar Russian Federation; Kheu River; Leg 22; Leg 80; Lomonosov Ridge; Mantle; Mantle plumes; Metals; North Atlantic; North Atlantic Seaway; North Atlantic igneous province; Os-188/Os-187; Osmium; Paleo-oceanography; Paleocene-Eocene Thermal Maximum; Paleogene; Platinum group; Russian Federation; Southern Europe; Spain; Stable isotopes; Tajikistan; Tertiary; Volcanism; Weathering; Zumaya Spain
Coordinates: N431753 N431753 W0021522 W0021522
S101243 S101242 E0935347 E0935346
N490516 N490518 W0130552 W0130554
N875200 N875200 E1361100 E1361100
Record ID: 2015117509
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands