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Title: A two million year record of low-latitude aridity linked to continental weathering from the Maldives
Author: Kunkelova, Tereza
Jung, Simon J. A.
de Leau, Erica S.
Odling, Nick
Thomas, Alex L.
Betzler, Christian
Eberli, Gregor P.
Alvarez-Zarikian, Carlos A.
Alonso-Garcia, Montserrat
Bialik, Or M.
Blättler, Clara L.
Guo, Junhua A.
Haffen, Sébastien
Horozal, Senay
Mee, Anna L. H.
Inoue, Mayuri
Jovane, Luigi
Lanci, Luca
Laya, Juan C.
Lüdmann, Thomas
Bejugam, Nagender N.
Nakakuni, Masatoshi
Niino, Kaoru
Petruny, Loren M.
Pratiwi, Santi D.
Reijmer, John J. G.
Reolid, Jesús
Slagle, Angela L.
Sloss, Craig R.
Su, Xiang
Swart, Peter K.
Wright, James D.
Yao, Zhengquan
Young, Jeremy R.
Lindhorst, Sebastian
Stainbank, Stephanie
Rueggeberg, Andres
Spezzaferri, Silvia
Carrasqueira, Igor
Hu, Siyao
Kroon, Dick
Keywords: Maldives
Orbital cycles
Indian-Asian history of aridity
Mid Pleistocene transition
Non-destructive core scanning
Composition of lithogenic fraction
IODP Exp 359
Issue Date: 18-Dec-2018
Publisher: BMC
Citation: Progress in Earth and Planetary Science. 2018 Dec 18;5(1):86
Abstract: Indian-Asian monsoon has oscillated between warm/wet interglacial periods and cool/dry glacial periods with periodicities closely linked to variations in Earth’s orbital parameters. However, processes that control wet versus dry, i.e. aridity cyclical periods on the orbital time-scale in the low latitudes of the Indian-Asian continent remain poorly understood because records over millions of years are scarce. The sedimentary record from International Ocean Discovery Program (IODP) Expedition 359 provides a well-preserved, high-resolution, continuous archive of lithogenic input from the Maldives reflecting on low-latitude aridity cycles. Variability within the lithogenic component of sedimentary deposits of the Maldives results from changes in monsoon-controlled sedimentary sources. Here, we present X-ray fluorescence (XRF) core-scanning results from IODP Site U1467 for the past two million years, allowing full investigation of orbital periodicities. We specifically use the Fe/K as a terrestrial climate proxy reflecting on wet versus dry conditions in the source areas of the Indian-Asian landmass, or from further afield. The Fe/K record shows orbitally forced cycles reflecting on changes in the relative importance of aeolian (stronger winter monsoon) during glacial periods versus fluvial supply (stronger summer monsoon) during interglacial periods. For our chronology, we tuned the Fe/K cycles to precessional insolation changes, linking Fe/K maxima/minima to insolation minima/maxima with zero phase lag. Wavelet and spectral analyses of the Fe/K record show increased dominance of the 100 kyr cycles after the Mid Pleistocene Transition (MPT) at 1.25 Ma in tandem with the global ice volume benthic δ18O data (LR04 record). In contrast to the LR04 record, the Fe/K profile resolves 100-kyr-like cycles around the 130 kyr frequency band in the interval from 1.25 to 2 million years. These 100-kyr-like cycles likely form by bundling of two or three obliquity cycles, indicating that low-latitude Indian-Asian climate variability reflects on increased tilt sensitivity to regional eccentricity insolation changes (pacing tilt cycles) prior to the MPT. The implication of appearance of the 100 kyr cycles in the LR04 and the Fe/K records since the MPT suggests strengthening of a climate link between the low and high latitudes during this period of climate transition.
Peer review: yes
DOI: s40645-018-0238-x
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