Australian Summer Monsoon variability in the past 14,000 years revealed by IODP Expedition 356 sediments

Type Article
Date 2019-02
Language English
Author(s) Ishiwa Takeshige1, 2, 3, Yokoyama Yusuke2, 3, Reuning Lars4, 8, McHugh Cecilia M.5, de Vleeschouwer David6, Gallagher Stephen J.7
Affiliation(s) 1 : Natl Inst Polar Res, Tokyo, Japan.
2 : Univ Tokyo, Atmosphere & Ocean Res Inst, Chiba, Japan.
3 : Univ Tokyo, Grad Sch Sci, Dept Earth & Planetary Sci, Tokyo, Japan.
4 : Rhein Westfal TH Aachen, Geol Inst, Energy & Mineral Resources Grp, Aachen, Germany.
5 : CUNY Queens Coll, Sch Earth & Environm Sci, Flushing, NY 11367 USA.
6 : Univ Bremen, MARUM Ctr Marine & Environm Sci, Bremen, Germany.
7 : Univ Melbourne, Sch Earth Sci, Melbourne, Vic, Australia.
8 : CAU Kiel Univ, Inst Geosci, Kiel, Germany.
Source Progress In Earth And Planetary Science (2197-4284) (Springeropen), 2019-02 , Vol. 6 , N. 17 , P. 10 p.
DOI 10.1186/s40645-019-0262-5
WOS© Times Cited 21
Keyword(s) International Ocean Discovery Program Expedition 356, Australian Summer Monsoon, Radiocarbon dating, Holocene climate variability, Northwestern Australia
Abstract

The International Ocean Discovery Program (IODP) Expedition 356 Site U1461 cored a Miocene to Holocene sedimentary sequence in the upper bathyal carbonate offshore northwestern Australia (NWA). The siliciclastic component of these strata is primarily derived from the Australian continent. Radiocarbon dating on macrofossils and planktonic foraminifera shows that the upper 14 m section at Site U1461 preserves Holocene sediments, recording regional climate variability. K/Ca ratios determined by X-ray fluorescence elemental analyses and %K determined by shipboard natural gamma ray analysis are interpreted as indicators of riverine run-off from the Australian continent. We document the consequences of the variability of the Australian Summer Monsoon (ASM) on the continental shelf of NWA. We report an increase in terrigenous input due to a riverine run-off after 11.5 ka, which reaches a maximum at similar to 8.5 ka. This maximum is the result of the enhanced ASM-derived precipitation in response to the southern migration of the Intertropical Convergence Zone (ITCZ). A decrease in riverine run-off due to a weakening of precipitation in the NWA region after 8.5 ka was caused by the northern migration of the ITCZ. We conclude that the ITCZ reached its southernmost position at 8.5 ka and enhanced precipitation in the NWA region. This Holocene record shows that even during interglacial periods, monsoonal variability was primarily controlled by the position of the ITCZ.

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Ishiwa Takeshige, Yokoyama Yusuke, Reuning Lars, McHugh Cecilia M., de Vleeschouwer David, Gallagher Stephen J. (2019). Australian Summer Monsoon variability in the past 14,000 years revealed by IODP Expedition 356 sediments. Progress In Earth And Planetary Science, 6(17), 10 p. Publisher's official version : https://doi.org/10.1186/s40645-019-0262-5 , Open Access version : https://archimer.ifremer.fr/doc/00496/60780/