Chemical Weathering in Jhelum River and its Tributaries, Kashmir Basin, Western Himalaya

2021 ◽  
pp. 203-232
Author(s):  
Riyaz Ahmad Mir ◽  
Farooq Ahmad Dar ◽  
Ghulam Jeelani
Keyword(s):  
Chemical Weathering ◽  
Western Himalaya ◽  
Kashmir Basin ◽  
Jhelum River

scholarly journals Marine sedimentary records of chemical weathering evolution in the western Himalaya since 17 Ma

Geosphere ◽  
2021 ◽  
Author(s):  
Peng Zhou ◽  
Thomas Ireland ◽  
Richard W. Murray ◽  
Peter D. Clift
Keyword(s):  
Climate Change ◽  
Chemical Weathering ◽  
Diffuse Reflectance Spectroscopy ◽  
Global Climate ◽  
Regional Climate ◽  
River Mouth ◽  
Regional Climate Change ◽  
Western Himalaya ◽  
Surface Reactivity ◽  
Sediment Geochemistry

The Indus Fan derives sediment from the western Himalaya and Karakoram. Sediment from International Ocean Discovery Program drill sites in the eastern part of the fan coupled with data from an industrial well near the river mouth allow the weathering history of the region since ca. 16 Ma to be reconstructed. Clay minerals, bulk sediment geochemistry, and magnetic susceptibility were used to constrain degrees of chemical alteration. Diffuse reflectance spectroscopy was used to measure the abundance of moisture-sensitive minerals hematite and goethite. Indus Fan sediment is more weathered than Bengal Fan material, probably reflecting slow transport, despite the drier climate, which slows chemical weathering rates. Some chemical weathering proxies, such as K/Si or kaolinite/(illite + chlorite), show no temporal evolution, but illite crystallinity and the chemical index of alteration do have statistically measurable decreases over long time periods. Using these proxies, we suggest that sediment alteration was moderate and then increased from 13 to 11 Ma, remained high until 9 Ma, and then reduced from that time until 6 Ma in the context of reduced physical erosion during a time of increasing aridity as tracked by hematite/goethite values. The poorly defined reducing trend in weathering intensity is not clearly linked to global cooling and at least partly reflects regional climate change. Since 6 Ma, weathering has been weak but variable since a final reduction in alteration state after 3.5 Ma that correlates with the onset of Northern Hemispheric glaciation. Reduced or stable chemical weathering at a time of falling sedimentation rates is not consistent with models for Cenozoic global climate change that invoke greater Himalayan weathering fluxes drawing down atmospheric CO2 but are in accord with the idea of greater surface reactivity to weathering.

scholarly journals Supplemental Material: Marine sedimentary records of chemical weathering evolution in the western Himalaya since 17 Ma

2021 ◽  
Author(s):  
P. Zhou ◽  
et al.
Keyword(s):  
Chemical Weathering ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Gulf Coast ◽  
Western Himalaya ◽  
Reflectance Spectroscopy ◽  
Sedimentary Records ◽  
College Station

Diffuse reflectance spectroscopy (DRS) data from IODP Sites U1456 and U1457 were collected at the Gulf Coast Repository (GCR) in College Station, Texas (USA) using a hand-held Minolta CM-2002 Spectrophotometer.

scholarly journals Supplemental Material: Marine sedimentary records of chemical weathering evolution in the western Himalaya since 17 Ma

2021 ◽  
Author(s):  
P. Zhou ◽  
et al.
Keyword(s):  
Chemical Weathering ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Gulf Coast ◽  
Western Himalaya ◽  
Reflectance Spectroscopy ◽  
Sedimentary Records ◽  
College Station

Diffuse reflectance spectroscopy (DRS) data from IODP Sites U1456 and U1457 were collected at the Gulf Coast Repository (GCR) in College Station, Texas (USA) using a hand-held Minolta CM-2002 Spectrophotometer.

Western Himalaya and Tibet

2009 ◽  
Author(s):  
Thomas Thomson
Keyword(s):  
Western Himalaya

Focus on Thermokarst Lakes in Indian Himalaya: Inception and Implication under Warming Climate

2020 ◽  
Vol 6 (2) ◽  
pp. 59-69
Author(s):  
Pratima Pandey ◽  
S. Nawaz Ali ◽  
Vikram Sharma ◽  
Prashant K. Champati Ray
Keyword(s):  
Western Himalaya ◽  
High Mountain ◽  
Thermokarst Lakes ◽  
Glacial Environments ◽  
Global Warming Scenario ◽  
Scientific Attention ◽  
Topographic Depressions ◽  
Permafrost Thawing ◽  
The Impact ◽  
Thaw Lakes

Thermokarst (Thaw) lakes are landforms found in topographic depressions created by thawing ground ice in permafrost zones. They play an important role in the regulation of climatic functions. These lakes are a manifestation of warming surface temperatures that accelerates the ice-rich permafrost to degrade by creating marshy hollows/ponds. In the current global warming scenario, the thermokarst lakes in the high mountain regions (Himalaya) are expected to grow further. This accelerate permafrost thawing which will affect the carbon cycle, hydrology and local ecosystems. This phenomenon has attracted huge scientific attention because it has led to a rapid mass change of glaciers in the region, including extensive changes occurring on peri-glacial environments. The most striking fact is the release of an enormous amount of greenhouse gases, including methane, carbon dioxide and nitrous oxide that is locked in these lakes. The present study delves into the thermokarst lakes in the upper reaches of Chandra Valley and Western Himalaya. The study also aims at designating the impact of their changes on the ecosystem, particularly their influence on the atmospheric greenhouse gas concentrations.

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