Chemical weathering in high‐sediment‐yielding watersheds, New Zealand

Lyons, W. Berry; Carey, Anne E.; Hicks, D. Murray; Nezat, Carmen A.

doi:10.1029/2003jf000088

Cited by 66 publications

(84 citation statements)

References 60 publications

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“…Therefore, we expect that although the period when we sampled was relatively dry, our measurements are a fair first-order representation of solute concentrations and ratios during the majority of the year. This is consistent with observations from other mountain belts, including the Southern Alps of New Zealand, the Himalayas, and the Andes, where rivers exhibit near-chemostatic behaviour over a range of discharge conditions (Lyons et al, 2005;West et al, 2005;Torres et al, 2015;Tipper et al, 2006).…”

Section: Landslide Weathering Products In Stream Watersupporting

confidence: 78%

Oxidation of sulfides and rapid weathering in recent landslides

et al. 2016

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Abstract. Linking together the processes of rapid physical erosion and the resultant chemical dissolution of rock is a crucial step in building an overall deterministic understanding of weathering in mountain belts. Landslides, which are the most volumetrically important geomorphic process at these high rates of erosion, can generate extremely high rates of very localised weathering. To elucidate how this process works we have taken advantage of uniquely intense landsliding, resulting from Typhoon Morakot, in the T'aimali River and surrounds in southern Taiwan. Combining detailed analysis of landslide seepage chemistry with estimates of catchment-bycatchment landslide volumes, we demonstrate that in this setting the primary role of landslides is to introduce fresh, highly labile mineral phases into the surface weathering environment. There, rapid weathering is driven by the oxidation of pyrite and the resultant sulfuric-acid-driven dissolution of primarily carbonate rock. The total dissolved load correlates well with dissolved sulfate -the chief product of this style of weathering -in both landslides and streams draining the area (R 2 = 0.841 and 0.929 respectively; p < 0.001 in both cases), with solute chemistry in seepage from landslides and catchments affected by significant landsliding governed by the same weathering reactions. The predominance of coupled carbonate-sulfuric-acid-driven weathering is the key difference between these sites and previously studied landslides in New Zealand (Emberson et al., 2016), but in both settings increasing volumes of landslides drive greater overall solute concentrations in streams.Bedrock landslides, by excavating deep below saprolite-rock interfaces, create conditions for weathering in which all mineral phases in a lithology are initially unweathered within landslide deposits. As a result, the most labile phases dominate the weathering immediately after mobilisation and during a transient period of depletion. This mode of dissolution can strongly alter the overall output of solutes from catchments and their contribution to global chemical cycles if landslide-derived material is retained in catchments for extended periods after mass wasting.

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Section: Landslide Weathering Products In Stream Watersupporting

confidence: 78%

Oxidation of sulfides and rapid weathering in recent landslides

et al. 2016

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“…3) is in accordance with observed correlations between chemical weathering rates and physical erosion for certain regions or geological settings (Gaillardet et al, 1999;Riebe et al, 2001;Millot et al, 2002;Lyons et al, 2005;West et al, 2005). However, in specific regions of the world opposite trends have been found as for the USA (see a complete discussion in Meybeck, 1994).…”

Section: Relations Between Dissolved and Particulate Silica Exports Asupporting

confidence: 69%

Global spatial distribution of natural riverine silica inputs to the coastal zone

et al. 2011

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Abstract. Silica, SiO 2 , in dissolved (DSi) and particulate (PSi) form, is both a major product of continental weathering as well as an essential nutrient in terrestrial and aquatic systems. Here we present estimates of the spatial distribution of riverine silica fluxes under natural conditions, i.e. without human influence, to ∼140 segments of the global coastal zone. Focussing on the construction of the DSi budget, natural DSi concentration is multiplied with discharge of rivers for each segment for documented basins and segments. Segments with no documentation available are estimated using clustered information based mainly on considerations of local lithology, climate, and lake retention. We approximate fluxes of particulate silica in various forms (PSi) from fluxes of suspended matter, calculated from existing models. Results have been established for silica fluxes, concentrations and yields for drainage basins of the different continents, oceans basins as well as coastal segment basins. For the continental surfaces actually draining into the oceans (exorheic regions, representing 114.7 million (M) km 2 ), 371 M t y −1 of DSi and 8835 M t y −1 of PSi are transported, corresponding to a mean concentration of 9.5 mg l −1 and 226 mg l −1 , and to a mean yield of 3.3 t km −2 y −1 and 77 t km −2 y −1 , respectively. DSi yields exceeding 6.6 t km −2 y −1 , i.e. >2× the global average, represent 17.4% of the global continental icefree exorheic area but correspond to 56.0% of DSi fluxes. Pacific catchments hold most of the hyper-active areas (>5× global average), suggesting a close connection between tecCorrespondence to: H. H. Dürr (h.durr@geo.uu.nl) tonic activity and DSi fluxes resulting from silicate weathering. The macro-filters of regional and marginal seas intercept 33% and 46% of the total dissolved and particulate silica fluxes. The mass of DSi received from rivers per unit square area of various oceans ranges over more than one order of magnitude. When expressed per unit volume and when individual regional seas are considered this figure ranges over two to three orders of magnitude, an illustration of the heterogeneity of the land to sea connection.

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“…Correction methods used by the individual authors typically rely on ratios of Ca-Na and Mg-Na (Gaillardet et al, 1999b). Data are from multiple sources (Carey et al, 2006;Gabet et al, 2010;Gaillardet et al, 1997;Gaillardet et al, 1999b;Gibbs, 1967;Goldsmith et al, 2008;Grove, 1972;Guyot et al, 1996;Hartmann and Moosdorf, 2011;Li et al, 1984;Lyons et al, 2005;Moquet et al, 2011;Mortatti and Probst, 2003;Qin et al, 2006;Schaller et al, 2001;Wolff-Boenisch et al, 2009). 8 Silicate weathering fluxes from volcanic lithologies, corrected for atmospheric and, where possible, for hydrothermal inputs (Gaillardet et al, 2011).…”

mentioning

confidence: 99%

Soils as pacemakers and limiters of global silicate weathering

Dixon

Blanckenburg

2012

Comptes Rendus. Géoscience

130

154

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The weathering and erosion processes that produce and destroy regolith are widely recognized to be positively correlated across diverse landscapes. However, conceptual and numerical models predict some limits to this relationship that remain largely untested. Using new global data compilations of soil production and weathering rates from cosmogenic nuclides and silicate weathering fluxes from global rivers, we show that the weatheringerosion relationship is capped by certain 'speed limits'. We estimate a soil production speed limit of between 320 to 450 t km -2 y -1 and the associated weathering rate speed limit of roughly 150 t km -2 y -1. These limits appear to be valid for a range of lithologies, and also extend to mountain belts, where soil cover is not continuous and erosion rates outpace soil production. We argue that the presence of soil and regolith is a requirement for high weathering fluxes from a landscape, and that rapidly eroding, active mountain belts are not the most efficient sites for weathering. . Ces limites semblent être valides pour une large gamme de roches-mères, et s'appliquent aussi aux zones montagneuses, où les sols ne recouvrent pas toute la surface et où les taux d'érosion dépassent ceux de la production du sol. Nous avançons que la présence d'un sol est un prérequis pour qu'un paysage exporte de fort flux d'altération, et que les chaînes de montagne actives présentant de forts taux d'érosion ne sont pas les sites les plus efficaces pour l'altération.

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Chemical weathering in high‐sediment‐yielding watersheds, New Zealand

Cited by 66 publications

References 60 publications

Oxidation of sulfides and rapid weathering in recent landslides

Oxidation of sulfides and rapid weathering in recent landslides

Global spatial distribution of natural riverine silica inputs to the coastal zone

Soils as pacemakers and limiters of global silicate weathering

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