Silicate rock weathering and atmospheric/soil CO2 uptake in the Amazon basin estimated from river water geochemistry: seasonal and spatial variations

Mortatti, Jefferson; Probst, Jean‐Luc

doi:10.1016/s0009-2541(02)00349-2

Cited by 200 publications

(130 citation statements)

References 40 publications

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“…It is important to note however, that for some of the streams in the upper Yarlung Tsangpo that may receive additions of Ca 2+ from gypsum weathering, this assumption could result in an overestimation of the CWR Carb . We calculated the total flux of cations derived from the weathering of carbonate and silicate components according to the methods outlined in Mortatti and Probst (2004) and Galy and FranceLanord (1999) and modified here to include hot spring/evaporite inputs. The amount of Ca 2+ derived from silicates and carbonates can be approximated by:…”

Section: Chemical Denudation Rates In the Yarlung Tsangpo-brahmaputramentioning

confidence: 99%

“…In this equation, factors of 1 are applied to K + and Na* and 2 for Ca 2+ and Mg 2+ , for the stoichiometric coefficients of weathering reactions for cations released and alkalinity produced by weathering reactions (Mortatti and Probst, 2004). CWR carb and CWR sil for the tributaries along the Nyang, Po, Yarlung Tsangpo, Lhasa He, and Siang vary significantly in response to tectonic and climatic factors.…”

Section: Hot Springsmentioning

confidence: 99%

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Major ion chemistry of the Yarlung Tsangpo–Brahmaputra river: Chemical weathering, erosion, and CO2 consumption in the southern Tibetan plateau and eastern syntaxis of the Himalaya

Hren

Chamberlain

Hilley

et al. 2007

Geochimica et Cosmochimica Acta

166

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The Yarlung Tsangpo-Brahmaputra river drains a large portion of the Himalaya and southern Tibetan plateau, including the eastern Himalayan syntaxis, one of the most tectonically active regions on the globe. We measured the solute chemistry of 161 streams and major tributaries of the Tsangpo-Brahmaputra to examine the effect of tectonic, climatic, and geologic factors on chemical weathering rates. Specifically, we quantify chemical weathering fluxes and CO 2 consumption by silicate weathering in southern Tibet and the eastern syntaxis of the Himalaya, examine the major chemical weathering reactions in the tributaries of the Tsangpo-Brahmaputra, and determine the total weathering flux from carbonate and silicate weathering processes in this region. We show that high precipitation, rapid tectonic uplift, steep channel slopes, and high stream power generate high rates of chemical weathering in the eastern syntaxis. The total dissolved solids (TDS) flux from the this area is greater than 520 tons km À2 yr À1 and the silicate cation flux more than 34 tons km À2 yr À1 . In total, chemical weathering in this area consumes 15.2 · 10 5 mol CO 2 km À2 yr À1 , which is twice the Brahmaputra average. These data show that 15-20% of the total CO 2 consumption by silicate weathering in the Brahmaputra catchment is derived from only 4% of the total land area of the basin. Hot springs and evaporite weathering provide significant contributions to dissolved Na + and Cl À fluxes throughout southern Tibet, comprising more than 50% of all Na + in some stream systems. Carbonate weathering generates 80-90% of all dissolved Ca 2+ and Mg 2+ cations in much of the Yarlung Tsangpo catchment.

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Section: Chemical Denudation Rates In the Yarlung Tsangpo-brahmaputramentioning

confidence: 99%

Section: Hot Springsmentioning

confidence: 99%

Major ion chemistry of the Yarlung Tsangpo–Brahmaputra river: Chemical weathering, erosion, and CO2 consumption in the southern Tibetan plateau and eastern syntaxis of the Himalaya

Hren

Chamberlain

Hilley

et al. 2007

Geochimica et Cosmochimica Acta

166

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“…800 × 10 6 t year -1 of suspended sediments (Guyot et al 2005, Martinez et al 2009) and approx. 270 × 10 6 t year -1 of dissolved elements (Mortatti andProbst 2003, Moquet 2011) into the Atlantic Ocean.…”

Section: Introductionmentioning

confidence: 99%

Yields of suspended sediment and dissolved solids from the Andean basins of Ecuador

Armijos

Laraque

Barba

et al. 2013

Hydrological Sciences Journal

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Water discharge and suspended and dissolved sediment data from three rivers (Napo, Pastaza and Santiago) in the Ecuadorian Amazon basin and a river in the Pacific basin (Esmeraldas) over a 9-year period, are presented. This data set allows us to present: (a) the chemical weathering rates; (b) the erosion rates, calculated from the suspended sediment from the Andean basin; (c) the spatio-temporal variability of the two regions; and (d) the relationship between this variability and the precipitation, topography, lithology and seismic activity of the area. The dissolved solids load from the Esmeraldas basin was 2 × 10 6 t year -1 , whereas for the Napo, Pastaza and Santiago basins, it was 4, 2 and 3 × 10 6 t year -1 , respectively. For stations in the Andean piedmont of Ecuador, the relationship between surface sediment and the total sediment concentration was found to be close to one. This is due to minimal stratification of the suspended sediment in the vertical profile, which is attributed to turbulence and high vertical water speeds. However, during the dry season, when the water speed decreases, sediment stratification appears, but this effect can be neglected in the sediment flux calculations due to low concentration rates. The suspended sediment load in the Pacific basin was 6 × 10 6 t year -1 , and the total for the three Amazon basins was 47 × 10 6 t year -1 . The difference between these contributions of the suspended sediment load is likely due to the tectonic uplift and the seismic and volcanic dynamics that occur on the Amazon side.

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“…In this study, a forward modeling approach was used to estimate the relative contribution of the different sources to the river (Galy and France-Lanord, 1999;Krishnaswami et al, 1999;Mortatti and Probst, 2003;Han and Liu, 2004;Moon et al, 2007;Xu and Liu, 2007).…”

Section: Chemical Budgetmentioning

confidence: 99%

Chemical weathering under mid- to cool temperate and monsoon-controlled climate: A study on water geochemistry of the Songhuajiang River system, northeast China

Liu

Zhang

et al. 2013

Applied Geochemistry

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Silicate rock weathering and atmospheric/soil CO2 uptake in the Amazon basin estimated from river water geochemistry: seasonal and spatial variations

Cited by 200 publications

References 40 publications

Major ion chemistry of the Yarlung Tsangpo–Brahmaputra river: Chemical weathering, erosion, and CO2 consumption in the southern Tibetan plateau and eastern syntaxis of the Himalaya

Major ion chemistry of the Yarlung Tsangpo–Brahmaputra river: Chemical weathering, erosion, and CO2 consumption in the southern Tibetan plateau and eastern syntaxis of the Himalaya

Yields of suspended sediment and dissolved solids from the Andean basins of Ecuador

Chemical weathering under mid- to cool temperate and monsoon-controlled climate: A study on water geochemistry of the Songhuajiang River system, northeast China

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