International Ocean Discovery Program (IODP) Expedition 355 drilled two sites (U1456 and U1457) in Laxmi Basin, located in the eastern Arabian Sea. The primary objective of
Expedition 355 is to better understand the impact that the Indian (southwest) summer monsoon has on weathering and erosion of the Himalayas and how this in turn affects mountain building.
Laxmi Basin is located within the Indus Fan, the second largest submarine fan in the world that has primarily been fed by the Indus River and its associated tributaries since the collision
of India and Eurasia in the Paleogene. Thus, the drill sites are ideally situated to record changes in erosion from the Himalayas through time, which requires a robust chronostratigraphic
framework. Analysis of 275 samples for calcareous nannofossil biostratigraphy from Hole U1457C has refined the age model that was produced onboard during Expedition 355. The section is
assigned to nannofossil Zones NN11–17 (late Miocene to early Pleistocene). In conjunction with shipboard magnetostratigraphy and planktonic foraminifer biostratigraphy, the age model
indicates variable sedimentation rates as well as the presence of an unconformity that spans at least 1.46 m.y. between ~5.5 and 4 Ma. Late Miocene sedimentation was variable at ~27
cm/k.y. before 7.42 Ma, but averaged ~2.4 cm/k.y. between 5.94 and 7.42 Ma. Sedimentation rates increased again from 5.94 to 5.59 Ma to ~20 cm/k.y., when deposition was interrupted for at
least 1.46 m.y. until ~4 Ma. After the hiatus and through the Pliocene, sedimentation rates were lower at ~3.6 cm/k.y. until the early Pleistocene when sedimentation rates reached ~8.9
cm/k.y. before slowing to ~3.4 cm/k.y. through 2.39 Ma. Further work to incorporate additional biostratigraphic and paleomagnetic constraints, should produce a robust chronostratigraphic
framework that is necessary to examine the evolution of the Himalayas as well as climate in the late Miocene through Pliocene. / A Thesis submitted to the Department of Earth, Ocean & Atmospheric Science in partial fulfillment of the requirements for the degree of Master of
Science. / Fall Semester 2015. / November 12, 2015. / Arabian Sea, biostratigraphy, miocene, nannofossil, pliocene / Includes bibliographical references. / Sherwood W. Wise, Professor Directing Thesis; Denise K. Kulhanek, Committee Member; William C. Parker, Committee Member; Leroy Odom, Committee
Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_291522 |
| Contributors | Routledge, Claire Marie (authoraut), Wise, Sherwood W. (professor directing thesis), Kulhanek, Denise Kay (committee member), Parker, William C., 1952- (committee member), Odom, A. L. (A. Leroy) (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Earth, Ocean, and Atmospheric Science (degree granting department) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (102 pages), computer, application/pdf |
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