ridm@nrct.go.th   ระบบคลังข้อมูลงานวิจัยไทย   รายการโปรดที่คุณเลือกไว้

Changing sedimentary environment during the late Quaternary: Sedimentological and isotopic evidence from the distal Bengal Fan

หน่วยงาน National Institute Of Oceanography (NIO), India

รายละเอียด

ชื่อเรื่อง : Changing sedimentary environment during the late Quaternary: Sedimentological and isotopic evidence from the distal Bengal Fan
นักวิจัย : Kessarkar, P.M. , Rao, V.P. , Ahmad, S.M. , Patil, S.K. , AnilKumar, A. , AnilBabu, G. , Chakraborty, S. , SounderRajan, R.
คำค้น : pelagic sediments , pelagic sedimentation , sedimentary environments , turbidities , provenance , quaternary , neodymium isotopes , strontium isotopes
หน่วยงาน : National Institute Of Oceanography (NIO), India
ผู้ร่วมงาน : -
ปีพิมพ์ : 2548
อ้างอิง : Deep-sea research. Part I. Oceanographic research papers, Vol.52; 1591-1615p. , http://drs.nio.org/drs/handle/2264/937
ที่มา : -
ความเชี่ยวชาญ : -
ความสัมพันธ์ : -
ขอบเขตของเนื้อหา : -
บทคัดย่อ/คำอธิบาย :

The sediments recovered from two gravity cores of the lower and distal Bengal Fan were investigated for sedimentological properties and Sr -Nd isotopes.Each core exhibits two distinct units, the lower unit 2 and upper unit 1 sediments. The unit 2 sediments are predominantly olive black/grey in colour with abundant finer silt-size fractions, low organic carbon and CaCO sub(3), quartz and mica in the coarse fraction, dominant illite and chlorite in the less than 2 Mu m fraction and uniform rock-magnetic properties. Biogenic constituents are extremely rare or restricted to the lower part of unit 2. The unit 1 sediments, on the other hand, are moderate brown/yellowish brown in colour with intermittent thin dark-coloured sediment layers. Higher clay, organic carbon, CaCO sub(3), and biogenic constituents in the coarse fraction, and enriched smectite and kaolinite in the o m fraction are typical. Magnetic susceptibility values are higher and correlate well with acid-insoluble residue content. Higher Rb, Sr, Sm and Nd concentrations, sup(87)Sr/sup(86)Sr ratios and more radiogenic epsilon Nd values are characteristic for unit 2 sediments compared to unit 1 in both the cores. The unit 2 sediments represent Pleistocene hemiturbidites, older than 13 sup(14)C kyr BP with their source from the northern Bay of Bengal (NBOB), derived from the Himalayas and transported by the Ganges -Brahmaputra (G -B)River system. Unit 1 sediments are calcareous pelagic sediments, which started depositing approx. 12 sup(14)C kyr BP, with its clastic sediments derived from the Himalayas and SE Indian/Sri Lankan margins. The change in lithofacies from unit 2 to unit 1 suggests that the sediment deposition by turbidity current activity ceased in the distal Bengal Fan at approx. 12 sup(14)C kyr BP, perhaps because of the rapid rise in sea-level during the melt water pulse 1A and Holocene.

บรรณานุกรม :
Kessarkar, P.M. , Rao, V.P. , Ahmad, S.M. , Patil, S.K. , AnilKumar, A. , AnilBabu, G. , Chakraborty, S. , SounderRajan, R. . (2548). Changing sedimentary environment during the late Quaternary: Sedimentological and isotopic evidence from the distal Bengal Fan.
    : National Institute Of Oceanography (NIO), India.
Kessarkar, P.M. , Rao, V.P. , Ahmad, S.M. , Patil, S.K. , AnilKumar, A. , AnilBabu, G. , Chakraborty, S. , SounderRajan, R. . 2548. "Changing sedimentary environment during the late Quaternary: Sedimentological and isotopic evidence from the distal Bengal Fan".
    : National Institute Of Oceanography (NIO), India.
Kessarkar, P.M. , Rao, V.P. , Ahmad, S.M. , Patil, S.K. , AnilKumar, A. , AnilBabu, G. , Chakraborty, S. , SounderRajan, R. . "Changing sedimentary environment during the late Quaternary: Sedimentological and isotopic evidence from the distal Bengal Fan."
    : National Institute Of Oceanography (NIO), India, 2548. Print.
Kessarkar, P.M. , Rao, V.P. , Ahmad, S.M. , Patil, S.K. , AnilKumar, A. , AnilBabu, G. , Chakraborty, S. , SounderRajan, R. . Changing sedimentary environment during the late Quaternary: Sedimentological and isotopic evidence from the distal Bengal Fan. : National Institute Of Oceanography (NIO), India; 2548.