Indian Ocean high-productivity event (10-8 Ma); linked to global cooling or to the initiation of the Indian monsoons?

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doi: 10.1130/G20662.1
Author(s): Gupta, Anil K.; Singh, Raj K.; Joseph, Sudheer; Thomas, Ellen
Author Affiliation(s): Primary:
Indian Institute of Technology, Department of Geology and Geophysics, Kharagpur, India
Other:
Wesleyan University, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 32(9), p.753-756. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. With GSA Data Repository Item 2004131. 40 refs.; illus., incl. 1 table, sketch map
Summary: Uplift of the Himalayas and Tibetan Plateau (ca. 10-8 Ma) has been said to be the main cause of the origin or intensification of the Indian monsoon system, because mountains modulate the land-sea thermal contrast. The intensification of the monsoons, in turn, is seen as the cause of major changes in fauna and flora on land (as a result of changing precipitation patterns) as well as in the Indian Ocean, where the monsoons drive increased upwelling and thus increased productivity. We argue that the interactions between the elevation of the Himalayas and Tibetan Plateau, the onset of the monsoons, and their effects on the Indian Ocean biota remain uncertain. The timing of these events (uplift, monsoons, and biotic change) is not well constrained. Neogene deep-sea benthic foraminiferal faunal and isotope records of the Ninetyeast Ridge combined with published data show that a major increase in biogenic productivity occurred at 10-8 Ma throughout the Indian Ocean, the equatorial Pacific, and southern Atlantic. We suggest that this Indian Ocean high-productivity event was not simply the result of monsoon-induced upwelling or nutrient delivery from the weathering of newly uplifted mountains, but may have been caused by strengthened wind regimes resulting from global cooling and the increase in volume of the Antarctic ice sheets.
Year of Publication: 2004
Research Program: DSDP Deep Sea Drilling Project
ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Antarctic ice sheet; Antarctica; Asia; Benthic taxa; Biofacies; C-13/C-12; Carbon; Cenozoic; Cluster analysis; Cooling; Cores; DSDP Site 214; DSDP Site 216; Deep Sea Drilling Project; Deep-sea environment; Factor analysis; Foraminifera; Geochemistry; Glacial environment; Glacial geology; Glaciomarine environment; Holocene; Ice sheets; India; Indian Ocean; Indian Peninsula; Invertebrata; Isotope ratios; Isotopes; Leg 121; Leg 22; Marine environment; Marine sediments; Microfossils; Monsoons; Neogene; Ninetyeast Ridge; O-18/O-16; ODP Site 752; ODP Site 757; ODP Site 758; Ocean Drilling Program; Oxygen; Paleo-oceanography; Paleoclimatology; Productivity; Protista; Quaternary; Sediments; Stable isotopes; Statistical analysis; Tertiary
Coordinates: S305329 S305328 E0933440 E0933439
S170128 S170123 E0881054 E0881048
N052302 N052303 E0902141 E0902140
S112013 S112013 E0884305 E0884305
N012743 N012744 E0901229 E0901228
Record ID: 2004070961
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