Evolution of chemical weathering processes and CO2 sequestration in the glaciated basins of Western Himalayas

2021 ◽  
Author(s):  
Kalyan biswal ◽  
Naveen kumar ◽  
Mohd soheb ◽  
Ramanathan al
Keyword(s):  
Chemical Weathering ◽  
Arid Zone ◽  
Drainage System ◽  
Molar Ratio ◽  
Crustal Rock ◽  
Carbonate Dissolution ◽  
Western Himalayas ◽  
Rock Types ◽  
Sequestration Rate ◽  
Specific Discharge

<p>Understanding of chemical weathering process involved in ionic elution helps in distinguishing the CO<sub>2</sub> sequestration rate at the different micro-climatic setup of Himalayan catchments. In the present study, we have selected three glaciated basins from two different climatic zones of Western Himalayas (Lato and Phutse from the cold-arid zone of Ladakh and Chhota Shigri from the monsoon-arid zone of Himachal Pradesh, India) for determining various solute sources, CO<sub>2</sub> sequestration rate and its control over melt-water quality. Solute sourcing models used in this work shows major cations like Ca<sup>2+</sup>  and Mg<sup>2+ </sup>are from crustal rock-weathering while Na<sup>+</sup> and K<sup>+</sup> sourced out from the sea-salt origin. However, major anions like SO<sub>4</sub><sup>2-</sup> (> 85%) were derived from the crustal origin and HCO<sub>3</sub><sup>-</sup> mostly derived from atmospheric sources (39% to 45 %) in all catchments except HCO<sub>3</sub><sup>-</sup> contribution from carbonation dissolution and silicate weathering is ~29% and ~16% for Ladakh catchments compared to ~9 % and ~29% in Chhota Shigri respectively. The solute model also reveals that the contribution of sulphate oxidative mediated carbonate dissolution (SOCD) in HCO<sub>3</sub><sup>-</sup> flux is relatively higher in Chhota Shigri (~16%) than others (~9%). It is also observed that catchment like Chhota Shigri having a combined network of channelized and distributed drainage patterns with lower specific discharge, more glacierized area, low pH, high pCO<sub>2</sub>, Low molar ratio [Ca<sup>2+</sup> + Mg<sup>2+</sup>]/[ Na<sup>+</sup> + K<sup>+</sup>], high SMF (~ 0.4), low CO<sub>2 carbonate</sub>/CO<sub>2 silicate</sub> ratio (~1.3) show relatively more sulphide oxidative and silicate weathered products than other catchments. Conversely, presence of excess non-glaciated areas in Stok and Phutse having well-channelized subsurface discharge with high CO<sub>2 carbonate</sub>/CO<sub>2 silicate </sub>ratio (~10 to ~5) show enhanced carbonation via atmospheric CO<sub>2</sub> (CAC) and carbonate dissolution with high annual CO<sub>2</sub> sequestration. Thus, varying subglacial drainage system, specific discharge pattern and reactive rock-types with distinct hydro-micro-climatic set up alters the chemical weathering mechanism in these catchments and control meltwater quality.</p>

scholarly journals Glacier naled evolution and relation to the subglacial drainage system based on water chemistry and GPR surveys (Werenskioldbreen, SW Svalbard)

2016 ◽  
Vol 57 (72) ◽  
pp. 19-30 ◽  
Author(s):  
Łukasz Stachnik ◽  
Jacob C. Yde ◽  
Marta Kondracka ◽  
Dariusz Ignatiuk ◽  
Magdalena Grzesik
Keyword(s):  
Ground Penetrating Radar ◽  
Chemical Weathering ◽  
Drainage System ◽  
Carbonate Dissolution ◽  
Drainage Pattern ◽  
Sulphide Oxidation ◽  
High Carbonate ◽  
Polythermal Glacier ◽  
Ground Penetrating ◽  
Subglacial Drainage

ABSTRACTGlacier naledi are extrusive ice masses that appear in front of glaciers as a consequence of refreezing of meltwater seepage during the accumulation season. These structures provide a unique opportunity to understand subglacial drainage activity during the accumulation season; however, only few detailed studies have previously focused on their characteristics. Here, we investigated glacier-derived naled assemblages in the proglacial zone of the polythermal glacier Werenskioldbreen (27.4 km2) in SW Svalbard. We determined the spatial distribution of naledi using ground penetrating radar surveys. The main subglacial drainage pattern was related to a channel under the medial moraine, and three sources are linked to a distributed subglacial drainage network. The relation between atmospherically-corrected (Ca2+ + Mg2+) and (SO42−) in sub-naled waters was closely related to sulphide oxidation coupled with carbonate dissolution (r = 0.99; slope = 1.6). This is consistent with the local lithology, which is dominated by schist containing carbonates. We also found high carbonate saturation indices in pale white ice layers within the naled. We conclude that sulphide oxidation coupled with carbonate dissolution is the dominant chemical weathering process in the subglacial drainage system of Werenskioldbreen during the accumulation season.

scholarly journals Straight to Low-Sinuosity Drainage Systems in a Variscan-Type Orogen—Constraints from Tectonics, Lithology and Climate

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 933
Author(s):  
Harald G. Dill ◽  
Andrei Buzatu ◽  
Sorin-Ionut Balaban
Keyword(s):  
Chemical Weathering ◽  
Current Model ◽  
Drainage System ◽  
Numerical Data ◽  
Structural Features ◽  
Acute Angle ◽  
Drainage Systems ◽  
Starting Point ◽  
Bedrock Lithology ◽  
The Impact

A holistic-modular approach has been taken to study the evolution of three straight to low-sinuosity drainage systems (=SSS) in an uplifted basement block of the Central European Variscides. The development of the SSS is described by means of a quadripartite model. (1) The geological framework of the SSS: Forming the lithological and structural features in the bedrock as a result of different temperature, pressure and dynamic-metamorphic processes. (2) Prestage of SSS: Forming the paleo-landscape with a stable fluvial regime as a starting point for the SSS. (3) Proto-SSS: Transition into the metastable fluvial regime of the SSS. (4) Modern SSS: Operation of the metastable fluvial regime Tectonics plays a dual role. Late Paleozoic fold tectonic creates the basis for the studied SSS and has a guiding effect on the development of morphotectonic units during the Neogene and Quaternary. Late Cenozoic fault tectonics triggered the SSS to incise into the Paleozoic basement. The change in the bedrock lithology has an impact on the fluvial and colluvial sediments as well as their landforms. The latter reflects a conspicuous modification: straight drainage system ⇒ higher sinuosity and paired terraces ⇒ hillwash plains. Climate change has an indirect effect controlling via the bedrock the intensity of mechanical and chemical weathering. The impact on the development of the SSS can be assessed as follows: Tectonics >> climate ≅ bedrock lithology. The three parameters cause a facies zonation: (1) wide-and-shallow valley (Miocene), (2) wide-angle V-shaped valley (Plio-Pleistocene), (3) acute-angle V-shaped valley (Pleistocene), (4) V-shaped to U-shaped valleys (Pleistocene-Holocene). Numerical data relevant for the hydrographic studies of the SSS are determined in each reference area: (1) Quantification of fluvial and colluvial deposits along the drainage system, (2) slope angles, (3) degree of sinuosity as a function of river facies, (4) grain size distribution, (5) grain morphological categorization, (6) grain orientation (“situmetry”), (7) channel density, (8) channel/floodplain ratios. Thermodynamic computations (Eh, pH, concentration of solubles) are made to constrain the paleoclimatic regime during formation of the SSS. The current model of the SSS is restricted in its application to the basement of the Variscan-Type orogens, to an intermediate crustal maturity state.

scholarly journals Linking the lithogenic, atmospheric, and biogenic cycles of silicate, carbonate, and organic carbon in the ocean

2009 ◽  
Vol 6 (4) ◽  
pp. 6579-6599
Author(s):  
S. V. Smith ◽  
J.-P. Gattuso
Keyword(s):  
Carbon Storage ◽  
Chemical Weathering ◽  
Dissolved Inorganic Carbon ◽  
North Pacific Ocean ◽  
Atmospheric Co2 ◽  
Molar Ratio ◽  
Co2 Uptake ◽  
Organic C ◽  
Co2 Gas ◽  
The Relationship

Abstract. Geochemical theory describes long term cycling of atmospheric CO2 between the atmosphere and rocks at the Earth surface in terms of rock weathering and precipitation of sedimentary minerals. Chemical weathering of silicate rocks takes up atmospheric CO2, releases cations and HCO3− to water, and precipitates SiO2, while CaCO3 precipitation consumes Ca2+ and HCO3− and releases one mole of CO2 to the atmosphere for each mole of CaCO3 precipitated. At steady state, according to this theory, the CO2 uptake and release should equal one another. In contradiction to this theory, carbonate precipitation in the present surface ocean releases only about 0.6 mol of CO2 per mole of carbonate precipitated. This is a result of the buffer effect described by Ψ, the molar ratio of net CO2 gas evasion to net CaCO3 precipitation from seawater in pCO2 equilibrium with the atmosphere. This asymmetry in CO2 flux between weathering and precipitation would quickly exhaust atmospheric CO2, posing a conundrum in the classical weathering and precipitation cycle. While often treated as a constant, Ψ actually varies as a function of salinity, pCO2, and temperature. Introduction of organic C reactions into the weathering-precipitation couplet largely reconciles the relationship. ψ in the North Pacific Ocean central gyre rises from 0.6 to 0.9, as a consequence of organic matter oxidation in the water column. ψ records the combined effect of CaCO3 and organic reactions and storage of dissolved inorganic carbon in the ocean, as well as CO2 gas exchange between the ocean and atmosphere. Further, in the absence of CaCO3 reactions, Ψ would rise to 1.0. Similarly, increasing atmospheric pCO2 over time, which leads to ocean acidification, alters the relationship between organic and inorganic C reactions and carbon storage in the ocean. Thus, the carbon reactions and ψ can cause large variations in oceanic carbon storage with little exchange with the atmosphere.

Granite emplacement mechanisms and tectonic controls: inferences from deformation studies

1988 ◽  
Vol 79 (2-3) ◽  
pp. 245-255 ◽  
Author(s):  
Donald H. W. Hutton
Keyword(s):  
Structural Geology ◽  
Typical Feature ◽  
Crustal Rock ◽  
Anisotropic Crystal ◽  
Rock Types ◽  
Granite Emplacement ◽  
Extensional Tectonic ◽  
Shear Sense ◽  
Tectonic Settings

ABSTRACTThis paper is a structural and tectonic approach to the emplacement and deformation of granitoids. The main methods available in structural geology are briefly reviewed and this emphasises that (a) a wealth of data, particularly strain and shear sense, which pertain to these problems, can be determined in and around plutons; (b) given the nature, unlike many other crustal rock types, of granites to crystallise from isotropic through weakly anisotropic crystal suspension fluids, that deformation which has occurred in these states may not be well preserved; and (c) it is entirely possible, using this methodology, to separate deformation resulting from externally originating tectonic stresses from that which is associated with internal magma-related stresses. It is also recommended that the genetically-based Cloosian classification of granite fabrics and structures into “primary” (magmatic flow/magmatic flow current) and “secondary”, be abandoned and that a more observationally-based approach which classifies granite deformation fabrics and structures according to their time of occurrence relative to the crystallisation state of the congealing magma, be adopted (i.e. pre-full crystallisation deformation and crystal plastic strain deformation).Examples of recent, structurally based, studies of emplacement mechanisms of plutons within tectonic settings are described and these show that, in general, space for magma can be created by the combination of tectonically-created cavities and internal magma-related buoyancy. This occurs in both transcurrent and extensional tectonic settings and there is no reason to doubt that it can happen in compressive-contractional regimes. It is concluded that transient and permanent space creation, such as may be exploited by available magmas, is a typical feature of the tectonically stressed and deforming lithosphere and this, in combination with the natural buoyancy and ascending tendency of magmas, can generate the varied emplacement mechanisms of granites.

scholarly journals Fertility of crustal rocks during anatexis

1996 ◽  
Vol 87 (1-2) ◽  
pp. 1-10 ◽  
Author(s):  
Alan Bruce Thompson
Keyword(s):  
Experimental Investigations ◽  
Crustal Rock ◽  
Dehydration Melting ◽  
Specific Pressure ◽  
Crustal Rocks ◽  
Rock Types ◽  
Increasing Temperature ◽  
Low Pressures ◽  
Kbar Pressure ◽  
Melting Relations

ABSTRACT:After many years of systematic experimental investigations, it is now possible to quantify the conditions for optimum fertility to melt production of most common crustal rock types as functions of temperature and to about 30 kbar pressure. Quartzo-feldspathic melting produces steady increases in melt proportion with increasing temperature. The exact melt fraction depends on the mineral mode relative to quartz-feldspar eutectics and the temperatures of mica dehydration melting reactions. Mica melting consumes SiO2 from residual quartz during the formation of refractory Al2SiO5, orthopyroxene, garnet or cordierite.A simple graphical interpretation of experimental results allows a deduction of the proportions of mica and feldspar leading to optimum fertility. In effect, the mica dehydration melting reactions, at specific pressure and are superimposed on quartz-feldspar melting relations projected onto Ab-An-Or. Fertility to melt production varies with the mica to feldspar ratio and pressure. Pelites are more fertile than psammites at low pressures (e.g. 5 kbar), especially if they contain An40 to An50 plagioclase. At higher pressure (e.g. 10-20 kbar) and for rocks containing albitic plagioclase, psammites are more fertile than pelites. For a typical pelite (e.g. with An25 at 20 kbar), the cotectic with muscovite lies at higher (≍·) and XAb (≍0·42) than with biotite :≍0·35; XAb(≍·), thus dehydration melting of muscovite requires 10% more plagioclase for fertility than does biotite.The first melts from dehydration melting of muscovite (with Plg + Qtz) are more sodic and form at lower temperatures than the first melts from Bio + Plg + Qtz. With increasing pressure, to at least 30 kbar, granite minimum and mica dehydration melts become more sodic. This indicates that of such melts is greater than 0·3.

Himalayan-Tibetan Erosion is not the Cause of Neogene Global Cooling

2021 ◽  
Author(s):  
Peter Clift ◽  
Tara Jonell
Keyword(s):  
Tibetan Plateau ◽  
Chemical Weathering ◽  
Drainage System ◽  
Nw Himalaya ◽  
Scientific Drilling ◽  
Global Cooling ◽  
Consumption Rates ◽  
Using Data ◽  
Uplift And Erosion ◽  
The Himalaya

<p>Does uplift and erosion of the Himalaya-Tibetan Plateau drive Cenozoic global cooling? We test this classic hypothesis put forward by Raymo and Ruddiman (1992) that suggests enhanced erosion in the Himalaya-Tibetan Plateau drove long-term Cenozoic global cooling through the chemical weathering of siliciclastic sediment. Here we examine three Asian marginal drainage systems (the Indus, Mekong and Pearl) where marine scientific drilling has yielded detailed seismic surveys and geochemical datasets that critically permit sediment mass flux and therefore chemical weathering flux budgets to be made. By compiling suitable bedrock endmember compositions for the fresh bedrock sources, it is possible to calculate the chemical weathering flux and relative CO<sub>2</sub> consumption rates for each drainage system into the early Miocene. We correct for evolving provenance of sediment delivered to the offshore and test the sensitivity of our calculations to selected bedrock endmembers, in light of the abundant mafic bedrock exposed Indus and Mekong systems. Appropriate Upper Continental Crust endmembers were further validated using data compiled from the GEOROC database. Regardless of which endmembers were used, calculations demonstrate that the total rate of CO<sub>2</sub> consumption decreased by 50% between ~16 and 5.3 Ma, especially within NW Himalaya as onshore erosion slowed and provenance shifted away from mafic arc units in the suture zone. This direct test of the uplift-erosion-weathering hypothesis establishes that chemical weathering fluxes did not increase during the Neogene and cannot be responsible for the drawdown of atmospheric CO<sub>2</sub> during that time period. Either additional mechanisms have been driving global cooling since 16 Ma or CO<sub>2</sub> consumption via chemical weathering is taking place in other areas outside the Himalaya-Tibetan Plateau.</p>

Carbonate dissolution rates in high salinity brines: Implications for post-Noachian chemical weathering on Mars

Icarus ◽  
2018 ◽  
Vol 307 ◽  
pp. 281-293 ◽  
Author(s):  
Charity M. Phillips-Lander ◽  
S.R. Parnell ◽  
L.E. McGraw ◽  
M.E. Elwood Madden
Keyword(s):  
Chemical Weathering ◽  
High Salinity ◽  
Carbonate Dissolution ◽  
Dissolution Rates

scholarly journals Subglacial chemical erosion: seasonal variations in solute provenance, Haut Glacier D’Arolla, Valais, Switzerland

1996 ◽  
Vol 22 ◽  
pp. 25-31 ◽  
Author(s):  
G. H. Brown ◽  
M. Sharp ◽  
M. Tranter
Keyword(s):  
Seasonal Variations ◽  
Chemical Weathering ◽  
Drainage System ◽  
Sea Salt ◽  
Major Conclusion ◽  
Chemical Erosion ◽  
Dissolved Species ◽  
Aerosol Dissolution ◽  
Weathering Process ◽  
Subglacial Drainage

This paper determines the provenance of solute in bulk meltwaters draining Haut Glacier d’Arolla, Valais, Switzerland, during the 1989 ablation season. Dissolved species are partitioned into components derived from sea salt, acid aerosol, dissolution of atmospheric CO2, and lithogenic sources, namely carbonates, sulphides and aluminosillicates. A major conclusion is that trace geochemically reactive minerals in the bedrock contribute the bulk of the solute found in runoff. Seasonal changes in solute provenance and in the dominant chemical weathering process are observed. Whereas the chemical weathering of aluminosillicate minerals by carbonation reactions remains relatively constant during the ablation season, the chemical erosion of carbonates shows distinct seasonal variations, reflecting changes in the nature of the subglacial drainage system. Subglacial drainage structure and bedrock type are key controls on the extent of subglacial chemical weathering.

Hydrogeochemistry of the Genoa River basin, New South Wales - Victoria

1976 ◽  
Vol 27 (1) ◽  
pp. 165 ◽  
Author(s):  
GE Reinson
Keyword(s):  
River Basin ◽  
Surface Waters ◽  
Chemical Weathering ◽  
Drainage Basin ◽  
Quartz Diorite ◽  
Weathering Rate ◽  
Water Types ◽  
Rock Types ◽  
Mixed Cation ◽  
Chemical Weathering Rate

The Genoa River basin is underlain largely by granitoid rocks which are of three types-quartz diorite-granodiorite, adamellite, and granite-adamellite-and to a lesser extent by metasediments and coarse elastics. Two types of surface water are present in the drainage basin, an Na-Cl type and a mixed-cation HCO3-Cl type. The genesis of these two water types isrelated primarily to differences in rate of chemical weathering of the three granitoid rock types. Mixed-cation HCO3,-Cl waters drain quartz diorite-granodiorite and adamellite terrain, but not granite-adamellite terrain, whereas the reverse is the case for the Na-CI waters. The quartz diorite-granodiorite and closely associated adamellite rock suites contain more minerals which are more readily weathered than does the granite-adamellite rock suite. These minerals (calcium plagioclase, biotite and hornblende) supply Ca, Mg, Na, and HCO3 to the waters through rapid dissolution. Where the rate of chemical weathering is high, the surface waters are characterized by a mixture of atmospheric salts and soluble products of weathering (mixed-cation HCO3-Cl type). Where the chemical weathering rate is low, the surface waters are dominated by atmospheric salts (Na-Cl type). The chemical weathering rate of the underlying bedrock remains as the controlling factor in the genesis of the two water types, even during low runoff periods when both the groundwater contribution to stream flow and the rate of evaporation are high.

Physicochemical weathering conditions of the characteristic white soil horizon at Al Firjah area and it’s vicinity in North Kordofan State, Central Sudan.

2021 ◽  
pp. 117-129
Author(s):  
Osman M El Hassan ◽  
Abubakr B Alfadil
Keyword(s):  
Chemical Weathering ◽  
Drainage System ◽  
Soil Horizon ◽  
Sample Analysis ◽  
Natural Processes ◽  
Central Sudan ◽  
Basement Rocks ◽  
Calcium Cation ◽  
Short Time ◽  
Rock And Soil

Mineral deposits and valuable materials are deposited, concentrated, and purified by natural processes during long or short time, chemical weathering reactions is a major one. Satelliteimages exhibit distinct white horizon of high reflectance. Investigation of this phenomenonreveals that these areas were associatedwith the distal reaches of the major part of the drainage system. Exposures of the basement rocks include metasediments marl, marble, and other silicate rocks(granite, granodiorite,meta andesite,….etc) at high land where the proximal reaches of the drainage system. These rock were subjected to chemical disintegration process of hydrolysis for silicateconstituent and dissolutionfor carbonate constituent and consequently these material were transportedby the drainage system as colloidal (kaolinite) and dissolved material(calcium cation and bicarbonate), eventually these material were deposited due to evaporation at flash delta to form the kaolinite carbonatesoil at Alfirjah area and it’s vicinity. Field observations in addition to rock and soil sample analysis forearm the above mentioned hypothesis.

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