Changing sediment sources in the Bay of Bengal: Evidence of summer monsoon intensification and ice-melt over Himalaya during the Late Quaternary

Baumberger, Tamara; Tyagi, Abhishek; Kurian, P. John

doi:10.1016/j.palaeo.2018.08.016

Cited by 22 publications

(7 citation statements)

References 74 publications

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“…In contrast, this abnormal change may have been attributed to an increase in the smectite input in sediments from the Burman source area or to a decrease in the amounts of sediment input from the Himalayas. Under the influence of the winter monsoon during the LGM, the denuded sediments on the Irrawaddy estuary shelf may have been transported southward through the west side of Andaman Island (Prajith et al, 2018), as was confirmed in previous work showing that the winter monsoon led to an increase in terrestrial materials from the Irrawaddy River to the Ninetyeast Ridge during the Heinrich event (Ahmad et al, 2005). However, the winter monsoon was strong in the western part of the study area from 21 to 15 ka (Fig.…”

Section: Factors Affecting Sediment Provisionsupporting

confidence: 81%

An Intertropical Convergence Zone shift controlled the terrestrial material supply on the Ninetyeast Ridge

Liu

Huang

et al. 2022

Clim. Past

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Abstract. Among various climate drivers, direct evidence for the Intertropical Convergence Zone (ITCZ) control of sediment supply on the millennial scale is lacking, and the changes in ITCZ migration demonstrated in paleoclimate records need to be better investigated. Here, we use clay minerals and Sr–Nd isotopes obtained from a gravity core on the Ninetyeast Ridge to track the corresponding source variations and analyze the relationship between terrestrial material supply and climatic changes. On the glacial–interglacial scale, chemical weathering weakened during the North Atlantic cold-climate periods and falling sea level hindered the transport of smectite into the study area due to the exposure of Andaman and Nicobar Islands. However, the influence of the South Asian monsoon on the sediment supply was not obvious on the millennial scale. We suggest that the north–south migration of the ITCZ controlled the rainfall in Myanmar and further directly determined the supply of clay minerals on the millennium scale because the transport of smectite was highly connected with the ITCZ location; thus, the regional shift of the ITCZ induced an abnormal increase in the smectite percentage during the late Last Glacial Maximum (LGM) in our records. The smectite percentage in the studied core is similar to distinct ITCZ records but different in some periods, revealing that regional changes in the ITCZ were significantly obvious, the ITCZ is not a simple north–south displacement, and closer connections occurred between the Northern–Southern Hemisphere in the eastern Indian Ocean during the late LGM.

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Section: Factors Affecting Sediment Provisionsupporting

confidence: 81%

An Intertropical Convergence Zone shift controlled the terrestrial material supply on the Ninetyeast Ridge

Liu

Huang

et al. 2022

Clim. Past

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“…Titanomagnetite is the most abundant magnetic mineral in Deccan basalts (Sangode et al, ) and fluvial sediments from peninsular India. The Krishna and Godavari Rivers have much higher magnetite contents compared to those sourced from the Himalayan regions (Sager & Hall, ; Phillips et al, ; Prajith et al, ; Sangode et al, , ). Magnetic, XRD and SEM results indicate the dominance of well‐preserved coarse titanomagnetite grains in zone‐III (Figures a–o, g‐4i, i–5l, c, 7g, 7k, c, 8g, and 8k).…”

Section: Discussionmentioning

confidence: 99%

Magnetic Mineralogical Approach for the Exploration of Gas Hydrates in the Bay of Bengal

et al. 2019

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We evaluate the environmental magnetic, geochemical, and sedimentological records from three sediment cores from potential methane-hydrate bearing sites to unravel linkages between sedimentation, shale tectonics, magnetite enrichment, diagenesis, and gas hydrate formation in the Krishna-Godavari basin. Based on downcore rock magnetic variations, four sedimentary magnetic property zones (I-IV) are demarcated. A uniform band of enhanced magnetic susceptibility (zone III) appears to reflect a period of high-sedimentation events in the Krishna-Godavari basin. Highly pressurized sedimentary strata developed as a result of increased sedimentation that triggered the development of a fault system that provided conduits for upward methane migration to enter the gas hydrate stability zone, leading to the formation of gas hydrate deposits that potentially seal the fault system. Magnetic susceptibility fluctuations and the presence of iron sulfides in a magnetically enhanced zone suggest that fault system growth facilitated episodic methane venting from deeper sources that led to multiple methane seepage events. Pyrite formation along sediment fractures resulted in diagenetic depletion of magnetic signals and potentially indicates paleo sulfate-methane transition zone positions. We demonstrate that a close correlation between magnetic susceptibility and chromium reducible sulfur concentration can be used as a proxy to constrain paleomethane seepage events. Our findings suggest that the interplay between higher sedimentation events and shale tectonism facilitated fluid/gas migration and trapping and the development of the gas hydrate system in the Krishna-Godavari basin. The proposed magnetic mineralogical approach has wider scope to constrain the understanding of gas hydrate systems in marine sediments.

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“…The focus of this study was not to correlate sediment provenance, as many studies have. The timing of erosion in the Himalayas to assess the force of drivers versus changes in sea level (Prajith et al, 2018;Reilly et al, 2020) is one of many such examples. The use of the published sediment core accumulation rates for model diffusion validation is novel in the present study.…”

Section: Discussionmentioning

confidence: 99%

“…Tropical sources, such as the Ganges and Amazon watersheds, were important, as they contribute to the major river systems deriving sediment from major mountain ranges. The published core data from the following areas (Table 1) were selected to reflect these critical areas, and they were compared with modeled erosion rates averaged in watershed source areas: Amazon River basin (Zhang et al, 2015), the Ganges River into the Bay of Bengal (Prajith et al, 2018) in the tropics, Lake Schrader in the western Arctic (Benson et al, 2019) in the Brooks Range in northern Alaska and also by the Lone Spruce Pond sediment core (Kaufman et al, 2012) in the Ahklun Range in southwestern Alaska. The eastern Arctic is represented by northern Siberian offshore deposits in the south Laptev Sea sourced from Lena River drainage (Bauch et al, 1999) and offshore deposits in south Kara Sea sourced from the lower Yenisei River drainage (Stein et al, 2002).…”

Section: Methodology and Datamentioning

confidence: 99%

Global variations in regional degradation rates since the Last Glacial Maximum mapped through time and space

Madoff

Putkonen

2022

Quat. res.

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Topographic diffusivity is an often-used metric of regolith mobility. It accounts for the collective effects of climate, substrate, fauna, flora, and other factors on hillslope degradation and is used to model natural lowering in landscapes. The present study assesses where temporal variations in diffusivity derived from known past climate fluctuations have occurred. We also determine where significant differences might result when modeling landscape degradation if a long-term constant diffusivity is applied instead of diffusivity that varies through time. A space-for-time substitution approach was implemented. Through use of a transfer function that correlates current diffusivities with air temperatures, we mapped the relative diffusivities globally at a 500 yr temporal resolution for 21 ka. The analyses spanned all land areas from the tropics to the poles with a spatial resolution of 3.70° latitude by 3.75° longitude using paleo-temperature data from the TraCE-21ka global paleoclimate model. The results show Arctic and subarctic regions with the highest relative maximum diffusivities and largest variance from current values. The results suggest strong surficial dynamics in the Arctic and subarctic regions driven by local and spatially transient deglaciation and long-term stability in the tropics that correlates with relatively stable climate there through the past 21 ka.

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Changing sediment sources in the Bay of Bengal: Evidence of summer monsoon intensification and ice-melt over Himalaya during the Late Quaternary

Cited by 22 publications

References 74 publications

An Intertropical Convergence Zone shift controlled the terrestrial material supply on the Ninetyeast Ridge

An Intertropical Convergence Zone shift controlled the terrestrial material supply on the Ninetyeast Ridge

Magnetic Mineralogical Approach for the Exploration of Gas Hydrates in the Bay of Bengal

Global variations in regional degradation rates since the Last Glacial Maximum mapped through time and space

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