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- Title
A 4 Million year record of wind variability over the Indian Ocean (IODP Exp. 359, site U1467, Maldives).
- Authors
Betzler, Christian; Lindhorst, Sebastian; Kroon, Dick; Giosan, Liviu
- Abstract
The lithogenic fraction of carbonate drift sediments from the Maldives provides a unique record of atmospheric transport over the northern central Indian Ocean during the past 3.5 to 4 Myrs. The record stems from the Inner Sea, which is a perched basin in this carbonate platform with a relief of more than 2000 m above the surrounding seafloor. The percentage of particles in the medium to coarse silt size fraction (8-63 µm), which is indicative of aeolian flux sums up to values of up to 35 % of the lithogenic fraction. This portion remains stable at a lower level (20 - 25 %) until about 1.4 Ma. In younger times, there is an increase in wind-transported material to 25 - 30 % and the variability is higher, starting with the Mid Pleistocene Transition (MPT). The size of the largest particles fed into the system (range 10-20 µm), indicated by the d90 of the grain-size distribution, increases between 4 and 3.5 Ma, and remains on a high level throughout the Pliocene Climate Optimum (3.3-3.0 Ma). Subsequently, there is a fining until 1.4 Ma, and a slight coarsening afterwards combined with a higher grain size variability. Superimposed onto these large trends there are pronounced higher frequency fluctuations with durations of 400 and 100 kyrs. The wind transport intensity rather follows a precessional controlled variability. This, however, is at the limit of the temporal data set resolution. Strontium and Neodymium isotope analysis of the lithogenic material indicate a mixed origin of the dust particles from two sources: A North Africa-Arabian-Middle East source and a Thar Desert Indian source.
- Subjects
MALDIVES; NORTH Africa; THAR Desert (India &; Pakistan); NEODYMIUM isotopes; STRONTIUM isotopes; DUST; ATMOSPHERIC transport; STABLE isotope analysis; PARTICLE size determination
- Publication
Geophysical Research Abstracts, 2019, Vol 21, p1
- ISSN
1029-7006
- Publication type
Article