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Geochemical and Lithium Isotopic Ins...

Pappala, Venkata Sailaja.

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Geochemical and Lithium Isotopic Insights to Chemical Weathering and Associated Carbon Feedbacks in Alaskan and Himalayan Proglacial Systems.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Geochemical and Lithium Isotopic Insights to Chemical Weathering and Associated Carbon Feedbacks in Alaskan and Himalayan Proglacial Systems./
Author:	Pappala, Venkata Sailaja.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2023,
Description:	165 p.
Notes:	Source: Dissertations Abstracts International, Volume: 85-05, Section: B.
Contained By:	Dissertations Abstracts International85-05B.
Subject:	Precipitation. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30673673
ISBN:	9798380720427

Geochemical and Lithium Isotopic Insights to Chemical Weathering and Associated Carbon Feedbacks in Alaskan and Himalayan Proglacial Systems.
Pappala, Venkata Sailaja.

Geochemical and Lithium Isotopic Insights to Chemical Weathering and Associated Carbon Feedbacks in Alaskan and Himalayan Proglacial Systems. - Ann Arbor : ProQuest Dissertations & Theses, 2023 - 165 p.

Source: Dissertations Abstracts International, Volume: 85-05, Section: B.

Thesis (Ph.D.)--North Carolina State University, 2023.

This item must not be sold to any third party vendors.

Chemical weathering of rocks results in the drawdown of CO2 from the atmosphere, which, in turn, regulates the global carbon cycle and Earth's climate. Studies suggest that glacial physical weathering enhances chemical weathering of rocks in glacial and proglacial systems, resulting in CO2 sequestration from the atmosphere, thereby acting as a negative climate feedback. Glacial chemical weathering is broadly understood in relation to the carbon cycle; however, nuanced carbon cycle-chemical weathering feedbacks exist in glaciated environments on modern timescales. In this dissertation, three studies were undertaken to understand the processes that control modern chemical weathering processes and related atmospheric CO2 drawdown potential in proglacial rivers from Southcentral Alaska (Matanuska River) and the Western Himalayas (Chandra, Bhaga, and Beas Rivers). Li isotopes (δ7Lidiss), major cation, and anion concentrations of proglacial waters from aforementioned locations were investigated to better understand these feedbacks.A spatial sampling approach was utilized in the first study to understand shifts in chemical weathering signatures with distance and carbon feedback implications in the Matanuska River system. A shift was observed from sulfuric acid (H2SO4) weathering signature (CO2 source) close to the terminus (<10 km) to a carbonic acid dominated (H2CO3) weathering signature (CO2sink) further downstream. The outcomes from this study captured the shifts in chemical weathering reactions and associated carbon feedbacks occurring along the length of the proglacial Matanuska River system.The second and third studies investigated the Li isotopic systematics in proglacial river systems from Southcentral Alaska (Matanuska River) and the Western Himalayas (Chandra, Bhaga, and Beas Rivers). Large variability in dissolved Li isotopic (δ 7Lidiss) compositions and Li/Na molar ratios were observed within close proximity to the glacier termini (<10 km) in the proglacial Matanuska River system (second study) and Western Himalayan proglacial river systems (third study). Similar geochemical trends were observed in these two studies, indicating Li uptake by secondary mineral phases (chlorite and illite) is likely controlling the observed variability in δ 7Lidiss in vastly different geographic settings. The results from the second and third studies suggest that the Li isotopic fractionation is more active in close proximity to the glaciated settings (<10 km), emphasizing the role of glacial physical and chemical weathering on δ 7Lidiss in immediate proglacial settings. The outcomes from these studies show that spatial and δ 7Lidiss investigations of proglacial settings are useful because these spatial studies capture shifts in geochemical weathering reactions and identifies the proximity to which the glacial weathering processes influence the meltwater chemistry and δ 7Lidissin proglacial settings.

ISBN: 9798380720427Subjects--Topical Terms:

3680799
Precipitation.

Geochemical and Lithium Isotopic Insights to Chemical Weathering and Associated Carbon Feedbacks in Alaskan and Himalayan Proglacial Systems.
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100 1 $a Pappala, Venkata Sailaja. $3 3765277
245 1 0 $a Geochemical and Lithium Isotopic Insights to Chemical Weathering and Associated Carbon Feedbacks in Alaskan and Himalayan Proglacial Systems.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2023
300 $a 165 p.
500 $a Source: Dissertations Abstracts International, Volume: 85-05, Section: B.
500 $a Advisor: Arendt, Carli;Owen, Lewis;Harmon, Russell;Liu, Xiaoming;Hyland, Ethan.
502 $a Thesis (Ph.D.)--North Carolina State University, 2023.
506 $a This item must not be sold to any third party vendors.
520 $a Chemical weathering of rocks results in the drawdown of CO2 from the atmosphere, which, in turn, regulates the global carbon cycle and Earth's climate. Studies suggest that glacial physical weathering enhances chemical weathering of rocks in glacial and proglacial systems, resulting in CO2 sequestration from the atmosphere, thereby acting as a negative climate feedback. Glacial chemical weathering is broadly understood in relation to the carbon cycle; however, nuanced carbon cycle-chemical weathering feedbacks exist in glaciated environments on modern timescales. In this dissertation, three studies were undertaken to understand the processes that control modern chemical weathering processes and related atmospheric CO2 drawdown potential in proglacial rivers from Southcentral Alaska (Matanuska River) and the Western Himalayas (Chandra, Bhaga, and Beas Rivers). Li isotopes (δ7Lidiss), major cation, and anion concentrations of proglacial waters from aforementioned locations were investigated to better understand these feedbacks.A spatial sampling approach was utilized in the first study to understand shifts in chemical weathering signatures with distance and carbon feedback implications in the Matanuska River system. A shift was observed from sulfuric acid (H2SO4) weathering signature (CO2 source) close to the terminus (<10 km) to a carbonic acid dominated (H2CO3) weathering signature (CO2sink) further downstream. The outcomes from this study captured the shifts in chemical weathering reactions and associated carbon feedbacks occurring along the length of the proglacial Matanuska River system.The second and third studies investigated the Li isotopic systematics in proglacial river systems from Southcentral Alaska (Matanuska River) and the Western Himalayas (Chandra, Bhaga, and Beas Rivers). Large variability in dissolved Li isotopic (δ 7Lidiss) compositions and Li/Na molar ratios were observed within close proximity to the glacier termini (<10 km) in the proglacial Matanuska River system (second study) and Western Himalayan proglacial river systems (third study). Similar geochemical trends were observed in these two studies, indicating Li uptake by secondary mineral phases (chlorite and illite) is likely controlling the observed variability in δ 7Lidiss in vastly different geographic settings. The results from the second and third studies suggest that the Li isotopic fractionation is more active in close proximity to the glaciated settings (<10 km), emphasizing the role of glacial physical and chemical weathering on δ 7Lidiss in immediate proglacial settings. The outcomes from these studies show that spatial and δ 7Lidiss investigations of proglacial settings are useful because these spatial studies capture shifts in geochemical weathering reactions and identifies the proximity to which the glacial weathering processes influence the meltwater chemistry and δ 7Lidissin proglacial settings.
590 $a School code: 0155.
650 4 $a Precipitation. $3 3680799
650 4 $a Minerals. $3 542841
650 4 $a Environmental conditions. $3 3550086
650 4 $a Open systems. $3 3566212
650 4 $a Oxidation. $3 714629
650 4 $a Atmosphere. $3 542821
650 4 $a Chemical reactions. $3 519248
650 4 $a Drainage. $3 548581
650 4 $a Carbon dioxide. $3 587886
650 4 $a Sulfuric acid. $3 1641667
650 4 $a Isotopes. $3 664463
650 4 $a Sediments. $3 3566210
650 4 $a Silica. $3 587794
650 4 $a Lithology. $3 3687992
650 4 $a Fractionation. $3 3706595
650 4 $a Carbon cycle. $3 3566213
650 4 $a Rivers. $3 519737
650 4 $a Lithium. $3 1638490
650 4 $a Climate. $3 694297
650 4 $a Alkalinity. $3 3566214
650 4 $a Geology. $3 516570
650 4 $a Biogeochemistry. $3 545717
650 4 $a Environmental science. $3 677245
650 4 $a Geochemistry. $3 539092
650 4 $a Information technology. $3 532993
650 4 $a Mineralogy. $3 516743
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710 2 $a North Carolina State University. $3 1018772
773 0 $t Dissertations Abstracts International $g 85-05B.
790 $a 0155
791 $a Ph.D.
792 $a 2023
793 $a English
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30673673