International Ocean Discovery Program Expedition 355 preliminary report; Arabian Sea monsoon; deep sea drilling in the Arabian Sea; constraining tectonic-monsoon interactions in South Asia; 31 March-31 May 2015

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doi: 10.2204/iodp.pr.355.2015
Author(s): Pandey, Dhananjai K.; Clift, Peter D.; Kulhanek, Denise K.; Ando, Sergio; Bendle, James A. P.; Bratenkov, Sophia; Griffith, Elizabeth M.; Gurumurthy, Gundiga P.; Hahn, Annette; Iwai, Masao; Khim, Boo-Keun; Kumar, Anil; Kumar, A. Ganesh; Liddy, Hannah M.; Lu Huayu; Lyle, Mitchell W.; Mishra, Ravi; Radhakrishna, Tallavajhala; Routledge, Claire M.; Saraswat, Rajeev; Saxena, Rakesh; Scardia, Giancarlo; Sharma, Girish K.; Singh, Arun D.; Steinke, Stephan; Suzuki, Kenta; Tauxe, Lisa; Tiwari, Manish; Xu Zhaokai; Yu Zhaojie
International Ocean Discovery Program, Expedition 355 Scientists, College Station, TX
Author Affiliation(s): Primary:
National Centre for Antarctic and Ocean Research, Department of Marine Geophysics, India
Other:
Louisiana State University, United States
Texas A&M University, United States
University of Milan, Italy
University of Birmingham, United Kingdom
Macquarie University, Australia
University of Texas, Arlington, United States
Manipal University, India
University of Bremen, Germany
Kochi University, Japan
Pusan National University, South Korea
Wadia Institute of Himalayan Geology-Dehradun, India
National Institute of Ocean Technology, India
University of Southern California, United States
Nanjing University, China
Oregon State University, United States
National Centre for Earth Science Studies, India
Florida State University, United States
National Institute of Oceanography, India
Oil and Natural Gas Corporation, India
Universidade Estadual Paulista, Brazil
Kumaun University, India
Banaras Hindu University, India
Hokkaido University, Japan
Scripps Institution of Oceanography, United States
Chinese Academy of Sciences/Institute of Oceanology, China
Université de Paris-Sud-Orsay, France
Source: Preliminary Report (International Ocean Discovery Program), Vol.355, 46p. Publisher: International Ocean Discovery Program, College Station, TX, United States. ISSN: 2372-9562
Note: In English. 182 refs.
Summary: The Indian (southwest) summer monsoon is one of the most intense climatic phenomena on Earth. Its long-term development has been linked to the growth of high topography in South and Central Asia. The Indian continental margin, adjoining the Arabian Sea, offers a unique opportunity to investigate tectonic-climatic interactions and the net impact of these processes on weathering and erosion of the western Himalaya. During International Ocean Discovery Program Expedition 355, two sites (U1456 and U1457) were drilled in Laxmi Basin in the eastern Arabian Sea to document the coevolution of mountain building, weathering, erosion, and climate over a range of timescales. In addition, recovering basement from the eastern Arabian Sea provides constraints on the early rifting history of the western continental margin of India with special emphasis on continental breakup between India and the Seychelles and its relationship to the plume-related volcanism of the Deccan Plateau. Drilling and coring operations during Expedition 355 recovered sediment from Sites U1456 and U1457 in the Laxmi Basin, penetrating 1109.4 and 1108.6 m below seafloor (mbsf ), respectively. Drilling reached sediment dated to 13.5-17.7 Ma (late early to early middle Miocene) at Site U1456, although with a large hiatus between the lowermost sediment and overlying deposits dated to <10.9 Ma. At Site U1457, a much longer hiatus occurs near the base of the cored section, spanning from 10.9 to ∼62 Ma. At both sites, hiatuses span ∼8.2-9.2 and ∼3.6-5.6 Ma, with a possible condensed section spanning ∼2.0-2.6 Ma, although the total duration for each hiatus is slightly different between the two sites. A major submarine fan draining the western Himalaya and Karakoram must have been supplying sediment to the eastern Arabian Sea since at least ∼17 Ma. Sand mineral assemblages indicate that the Greater Himalayan Crystalline Sequence was fully exposed to the surface by this time. Most of the recovered sediment appears to be derived from the Indus River and includes minerals that are unique to the Indus Suture Zone, in particular glaucophane and hypersthene, most likely originating from the structural base of the Kohistan arc. Pliocene sandy intervals at Site U1456 were deposited in lower fan "sheet lobe" settings, with intervals of basin plain turbidites separated by hemipelagic muddy sections deposited during the Miocene. Site U1457 is more distal in facies, reflecting its more marginal setting. No major active lobe appears to have affected the Laxmi Basin since the Middle Pleistocene (∼1.2 Ma). We succeeded in recovering sections spanning the 8 Ma climatic transition, when monsoon intensity is believed to have changed strongly, although the nature of this change awaits postcruise analysis. We also recovered sediment from a large mass transport deposit measuring ∼330 and ∼190 m thick at Sites U1456 and U1457, respectively. This section includes an upper sequence of slump-folded muddy and silty rocks, as well as underlying calcarenites and limestone breccias, together with smaller amounts of volcanic clasts, all of which are likely derived from the western Indian continental shelf. Identification of similar facies on the regional seismic lines in Laxmi Basin suggests that these deposits form parts of one of the world's largest mass transport deposits. Coring of igneous basement was successful at Site U1457.
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; 20 Geophysics, Applied; Algae; Arabian Sea; Basement; Biostratigraphy; Boreholes; Calcium carbonate; Carbon; Cenozoic; Chemostratigraphy; Cores; Expedition 355; Foraminifera; Geophysical methods; Geophysical profiles; Geophysical surveys; IODP Site U1456; IODP Site U1457; Igneous rocks; Indian Ocean; Indus Fan; International Ocean Discovery Program; Invertebrata; Laxmi Basin; Lithostratigraphy; Magnetostratigraphy; Marine sediments; Microfossils; Nannofossils; Nitrogen; Paleomagnetism; Plantae; Plate tectonics; Pleistocene; Protista; Provenance; Quaternary; Rifting; Sediments; Seismic methods; Seismic profiles; Seismic stratigraphy; Submarine fans; Sulfur; Surveys; Tertiary
Coordinates: N163717 N163717 E0685020 E0685020
N170957 N170957 E0675548 E0675548
Record ID: 2015098671
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