Long-term evolution of sediment provenance in the Indus Fan inferred from clay 87Sr/86Sr and εNd from IODP Sites U1456 and U1457

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Author(s): Carter, Samantha; Griffith, Elizabeth M.; Scher, Howie; Dellapenna, Timothy Michael; Clift, Peter Dominic
Author Affiliation(s): Primary:
Ohio State University, School of Earth Sciences, Columbus, OH, United States
University of South Carolina Columbia, United States
Texas A&M University-Galveston, United States
Louisiana State University, United States
Volume Title: AGU 2018 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2018; American Geophysical Union 2018 fall meeting, Washington, DC, Dec. 10-14, 2018. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The process of continental erosion and its relationship to climate and mountain building has significant impacts on Earth's environment. How these processes are related is an important area of study so we may increase our understanding of how the solid Earth interacts with the atmosphere and climate system. The intensity and pattern of monsoons affecting the Himalayan region have a significant influence over weathering and erosion, affecting erosion within drainage basins, the supply of sediments to the seas, and surface water circulation. Changes in the monsoon in the geologic past can be studied using provenance records of sediments deposited from the Indus River. The radiogenic isotopic composition of strontium (87Sr/86Sr) and neodymium (εNd) have been used extensively to characterize provenance of detrital sediments. A record of sediment provenance in the Indus Fan is presented by analyzing the 87Sr/86Sr and εNd signatures of the clay fraction in sediments from International Ocean Discovery Program (IODP) Expedition 355 Sites U1456 and U1457. This record is coupled with additional records of bulk grain size and K/Al ratios of clay to investigate their relationship to changes in provenance. This clay fraction record will be compared to the carbonate-free bulk sediment (Clift et al., unpublished) to see if sediment transport and size sorting play a significant role in the sediment isotopic records. Initial results indicate trends of changing sediment provenance to the Indus Fan over the past 11 Myr. Comparison to pore water 87Sr/86Sr (Carter et al., 2017) confirms there is no alteration of clay 87Sr/86Sr due to diagenesis. There are distinct differences between the bulk fraction and clay fraction provenance during some intervals (particularly over the past 3.5 Myr), suggesting sediment transport or size sorting plays a role at these sites. Due to the distal nature of these sites in the fan, there might be less influence of sorting in the provenance signal from the clay fraction. Neodymium data will be presented to further differentiate these changes in provenance. The sensitivity of the clay 87Sr/86Sr to chemical weathering intensity will also be evaluated by combining with the chemical index of alteration and clay mineralogical indices (Clift et al., unpublished).
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Alkaline earth metals; Arabian Sea; Cenozoic; Expedition 355; IODP Site U1456; IODP Site U1457; Indian Ocean; Indus Fan; International Ocean Discovery Program; Isotope ratios; Isotopes; Marine sedimentation; Marine sediments; Metals; Provenance; Quaternary; Sedimentation; Sediments; Sr-87/Sr-86; Stable isotopes; Strontium
Coordinates: N163717 N163718 E0685021 E0685020
N170957 N170957 E0675549 E0675548
Record ID: 2019050458
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