FN Archimer Export Format
PT J
TI Late Cretaceous changes in oceanic currents and sediment sources in the eastern Tethys: insights from Nd isotopes and clay mineralogy
BT 
AF Chenot, Elise
   Pucéat, Emmanuelle
   FRESLON, Nicolas
   Deconinck, Jean-François
   Razmjooei, Mohammad Javad
   Thibault, Nicolas
AS 1:1,2;2:2;3:2;4:2;5:3,4;6:4;
FF 1:;2:;3:;4:;5:;6:;
C1 Institut Polytechnique Lasalle Beauvais, 19 Rue Pierre Waguet, BP 30313, F-60026 Beauvais, France
   Biogéosciences, UMR 6282, 6 boulevard Gabriel, Université Bourgogne Franche-Comté, F-21000 Dijon, France
   Department of Geology, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran
   IGN, Univ. of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen, Denmark
C2 INST POLYTECH LASALLE, FRANCE
   UNIV BOURGOGNE FRANCHE COMTE, FRANCE
   UNIV SHAHID BEHESHTI, IRAN
   IGN, DENMARK
IF 4.956
TC 1
UR https://archimer.ifremer.fr/doc/00656/76785/78195.pdf
LA English
DT Article
DE ;Ocean circulation;Late Cretaceous;Continental weathering;Climate;Shahneshin section;Iran
AB The Late Cretaceous is marked by geodynamical changes including Africa-Eurasia convergence that resulted in the narrowing of the Tethys Ocean and in ophiolite obduction along the southern margin of the various continental blocks in eastern Tethys. Geochemical and mineralogical analyses were performed on the Shahneshin section (Zagros Basin - eastern Tethys), to explore the consequences of this evolution on oceanic circulation, and to estimate the role of ophiolite weathering that can impact climate through atmospheric CO2 drawdown. [Ni] and [Cr] sharply increase in the uppermost Campanian – Maastrichtian interval and are not coeval with an increase in the Nd isotope composition (ɛNd) of the detrital fraction of the sediments. This is interpreted as reflecting weathering of the mantellic, ultramafic part of the ophiolite sequence at that time, implying that ophiolites were exposed on the continents as soon as the Coniacian in the vicinity of the Zagros Basin. Hence their weathering could have contributed to the Late Cretaceous climatic cooling. Clay mineralogy reveals an alternation of kaolinite-rich humid periods (Coniacian/Santonian and late early Campanian to latest Campanian) and kaolinite-depleted arid periods (early Campanian and the latest Campanian to late Maastrichtian). The ɛNd(t) of bathyal waters (carbonate leached fraction) appears quite radiogenic, in the range of -3.4 to -5.2 ɛ-units, about 2 to 4 ɛ-units higher than the detrital fraction. Changes in the ɛNd(t) of detrital material delivered to the Zagros Basin appear to control the ɛNd(t) of the local bottom waters from the Coniacian to the middle Campanian. By contrast, decoupling of detrital ɛNd(t) from that of the local bottom waters from the middle Campanian to the Maastrichtian points to increasing fluxes of westward flowing Pacific radiogenic water masses into the eastern Tethys at that time. These results support an intensification of the Tethyan Circumglobal Current, likely related to the narrowing of the Tethyan seaway. 
PY 2021
PD MAR
SO Global And Planetary Change
SN 0921-8181
PU Elsevier BV
VL 198
UT 000756770000001
DI 10.1016/j.gloplacha.2020.103353
ID 76785
ER

EF