Chemical weathering outputs from the flood plain of the Ganga

Bickle, M. J.; Chapman, H. J.; Tipper, Edward T.; Galy, Αlbert; Rocha, Christina L. De La; Ahmad, Talat

doi:10.1016/j.gca.2018.01.003

Cited by 48 publications

(100 citation statements)

References 79 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…12d, e). Similar results were reported earlier from the same region (France-Lanord et al, 2003;Tipper et al, 2006;Gabet et al, 2008;Bickle et al, 2018) and from other basins of the world (White and Blum, 1995;Gaillardet et al, 1999).…”

Section: Runoff Controlsupporting

confidence: 92%

“…This suggests that mobilization of * Ca and * Mg might be differently affected by seasonal controls. An additional process to partly explain the decreasing pattern in the * Ca/ * Mg ratio towards lower elevation sites is instream calcite precipitation as was suggested for the Himalayan drainage network (Galy and France-Lanord, 1999;Dalai et al, 2002;Bickle et al, 2018).…”

Section: Elemental Ratios Of Weathering Productsmentioning

confidence: 93%

“…Recent work on flood plain weathering below the Himalaya front suggests that the flood plains are a dominant location of silicate weathering of detrital material originating from the Himalaya (Lupker et al, 2012). Bickle et al (2018) reported that chemical weathering fluxes in the flood plain area exceeds chemical weathering fluxes from the Himalayas.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Seasonal variations of biogeochemical matter export along the Langtang-Narayani river system in central Himalaya

Bhatt

Hartmann

Acevedo

2018

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Weathering and suspended matter fluxes of the Langtang Narayani river system in central Nepal Himalaya have been investigated at 16 stations for one year, based on monthly water sampling in the lower reaches and bi-monthly in higher elevation areas, to determine temporal variations of weathering fluxes along an elevation profile between 169 and 3989 m asl. Results indicate that the lower reaches are the dominant places of weathering in the system. The sum of major base cation fluxes is 2.9 to 9.2 higher during the monsoon season compared to the pre-monsoon season. Alkalinity and sea-salt corrected sulfate were the dominant anions (97%). The lowest downstream location exports 1611 tons km À2 yr À1 suspended sediment, 78.56 tons km À2 yr À1 of major cations (Na + K + Mg + Ca), 12.72 tons km À2 yr À1 of silica (4-fold higher than at the middle reaches of the basin), and 1.9 Â 10 6 mol km À2 yr À1 of dissolved inorganic carbon (8.9-fold higher than at the middle reaches). Nitrogen and phosphorus concentrations are low in general and dissolved organic carbon export is within expected ranges. River water pCO 2 values are low in general, with exception of those main stem reaches where tributaries with relevant pyrite oxidation processes, and lower pH, alter the pattern locally. Element ratios suggest seasonal shifts in the weathering flux generation, modulated by the monsoon system. During the peak of the monsoon season the most relevant weathering products alkalinity, * SO 4 , * Ca and * Mg were not diluted, and increased concentrations observed at the lower reaches suggests an enhanced mobilization during this period of the year. Carbonate weathering exceeds silicate weathering along the drainage network and the carbonate-to silicate-cation mol ratio is 3.5 at the outlet. Sulfide oxidation probably enhances weathering rates besides the control of the soil-rock partial pressure of CO 2 . The ratio of the total alkalinity flux to sea-salt corrected sulfate equivalent flux at the base of the Himalaya at Narayanghat was 5.7. Sea-salt corrected sulfate equivalent export is about the same as the silicate cation-equivalent flux that leaves the system (98%). Therefore, further research on sulfur isotopes might be helpful to support the hypothesis that pyrite oxidation compensates for the idealized CO 2 -consumption by silicate weathering in the studied area.

show abstract

Section: Runoff Controlsupporting

confidence: 92%

Section: Elemental Ratios Of Weathering Productsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Seasonal variations of biogeochemical matter export along the Langtang-Narayani river system in central Himalaya

Bhatt

Hartmann

Acevedo

2018

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

show abstract

“…In this study, we present time series major ions and Sr concentration data for the Brahmaputra River (at Guwahati, India) on a weekly to biweekly basis to constrain its solute sources and their relative contributions during different flow stages. Prior to this, few earlier studies have also reported seasonal variations of the water chemistry for the Himalayan rivers, such as the Ganga (Bickle et al, , 2018Chakrapani & Saini, 2009;Tipper et al, 2006;, Brahmaputra (Rai & Singh, 2007;Singh et al, 2005), and Irrawaddy and Salween (Chapman et al, 2015). This large river system predominantly flows through Himalaya and Tibet region and supplies~1.8% of the global water flux from only 0.4% of the global continental area (Das et al, 2016;Singh, 2007).…”

Section: Introductionmentioning

confidence: 98%

Temporal Variations in Water Chemistry of the (Lower) Brahmaputra River: Implications to Seasonality in Mineral Weathering

Samanta

Tripathy

Das

2019

Geochem Geophys Geosyst

View full text Add to dashboard Cite

Dissolved major ions and Sr concentrations of the Brahmaputra River at Guwahati, India, have been investigated on weekly basis for one year to understand the seasonality in weathering pattern and relative contributions from possible solute sources. Comparison of major ion data sets from present and earlier studies for this location shows no appreciable change during last ~50 years. Elemental concentrations and Ca/Na* (Na* = Na − Cl) ratio of the Brahmaputra covary (inversely) with the water discharge; the degree of seasonality, however, is less pronounced compared to other Himalayan (e.g., Ganga and Salween) rivers. The monthly averaged Ca/Si ratios of the Brahmaputra (3.7 ± 0.2), which is lower by ~2 times than those reported earlier for the Ganga outflow (6 ± 1), show minimal (~6%) seasonal changes. Seasonal variability in Na*/K with higher ratios during non‐monsoon period has been attributed to proportionally higher Na supply from hot springs and/or alkaline salts. The silicate‐derived cations (Cats) and Sr (Srs) have been estimated using an inversion method. Although these estimated values broadly show seasonal changes, the average Cats and Srs values for the monsoon (26 ± 4% [Cats]; 26 ± 6% [Srs]) and non‐monsoon (27 ± 3% (Cats); 24 ± 4% (Srs)) seasons are statistically same. These estimates indicate a weak runoff‐weathering linkage for the Brahmaputra river. Outcomes from this study suggest that the chemical weathering intensity of this basin is more dominated by regional rapid weathering around the eastern syntaxis than the climatic (runoff) parameters.

show abstract

“…important feedback regarding Earth's climate [6]. Nevertheless, large scale uncertainties with reference to distinction of silicate weathering flux from total flux, as well as sensitivity to tectonic, lithological, and climate controls remain and the geomorphological environment in which chemical weathering takes place [7,8].…”

Section: Introductionmentioning

confidence: 99%

Silica Enrichment in a Volcanic Setting Using Petrographic Analyses and Mass Balance Calculations Using Trace Element Zircon

Wadia

2016

JGRE

View full text Add to dashboard Cite

Formulating the original composition of weathered tephra can be a challenging task. A previous study by Wadia (1998 and 2007) demonstrated the enrichment of silica according to the hypothesis that the percentage of aluminum oxide remains constant within the unweathered parent material and its weathered counterpart (Faure, 1991), which indicated the average enrichment of silica to be 6.5%. This study demonstrates the enrichment of microcrystalline-cryptocrystalline quartz in the Reid's Mistake Formation of the Newcastle Coal measures of Sydney Basin, Australia, incorporating petrographic analyses and MBC (mass balance calculations) using trace element zircon as the immobile element. For MBC, zircon is more favorable, as it is a trace element that tends to be immobile during the process of chemical weathering. The composition of the unweathered reference samples was collected from the Tertiary volcanic complexes of Northeastern New South Wales and Southeastern Queensland. ICP-AES (inductively coupled plasma-atomic emission spectroscopy) was used to determine the chemical composition of the weathered samples. The quantitative enrichment of silica was provided by performing MBC using zircon as the immobile trace element. The petrographic analyses results indicated that the tephra was subjected to chemical weathering in a meteoric regime, as represented by minerals observed in the weathered tephra. The silica enrichment by MBC involving zircon resulted in 40.11%, which is indicative of chemical weathering, and was additionally supported by the presence of chert lenses in the volcanic horizon, indicating the enrichment of silica as a result of chemical weathering.

show abstract

Chemical weathering outputs from the flood plain of the Ganga

Cited by 48 publications

References 79 publications

Seasonal variations of biogeochemical matter export along the Langtang-Narayani river system in central Himalaya

Seasonal variations of biogeochemical matter export along the Langtang-Narayani river system in central Himalaya

Temporal Variations in Water Chemistry of the (Lower) Brahmaputra River: Implications to Seasonality in Mineral Weathering

Silica Enrichment in a Volcanic Setting Using Petrographic Analyses and Mass Balance Calculations Using Trace Element Zircon

Contact Info

Product

Resources

About