U-series disequilibria in suspended river sediments and implication for sediment transfer time in alluvial plains: The case of the Himalayan rivers

Granet, M.; Chabaux, François; Stille, Peter; Dosseto, Anthony; France‐Lanord, Christian; Blaes, E.

doi:10.1016/j.gca.2010.02.016

Cited by 82 publications

(61 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3b using T cut values selected such that the MTT for each distribution shape varied between 10 3 and 10 6 years. This approach is consistent with field estimates of MTTs, which range from 10 3 to 5×10 5 years when measured using sediment budgeting (Blöthe and Korup, 2013) or radionuclide approaches (Dosseto et al, 2006;Granet et al, 2010;Wittmann et al, 2015Wittmann et al, , 2016Li et al, 2016).…”

Section: Radiocarbon As a Poc Storage Tracersupporting

confidence: 81%

Model predictions of long-lived storage of organic carbon in river deposits

et al. 2017

View full text Add to dashboard Cite

Abstract. The mass of carbon stored as organic matter in terrestrial systems is sufficiently large to play an important role in the global biogeochemical cycling of CO 2 and O 2 . Field measurements of radiocarbon-depleted particulate organic carbon (POC) in rivers suggest that terrestrial organic matter persists in surface environments over millennial (or greater) timescales, but the exact mechanisms behind these long storage times remain poorly understood. To address this knowledge gap, we developed a numerical model for the radiocarbon content of riverine POC that accounts for both the duration of sediment storage in river deposits and the effects of POC cycling. We specifically target rivers because sediment transport influences the maximum amount of time organic matter can persist in the terrestrial realm and river catchment areas are large relative to the spatial scale of variability in biogeochemical processes.Our results show that rivers preferentially erode young deposits, which, at steady state, requires that the oldest river deposits are stored for longer than expected for a well-mixed sedimentary reservoir. This geometric relationship can be described by an exponentially tempered power-law distribution of sediment storage durations, which allows for significant aging of biospheric POC. While OC cycling partially limits the effects of sediment storage, the consistency between our model predictions and a compilation of field data highlights the important role of storage in setting the radiocarbon content of riverine POC. The results of this study imply that the controls on the terrestrial OC cycle are not limited to the factors that affect rates of primary productivity and respiration but also include the dynamics of terrestrial sedimentary systems.

show abstract

Section: Radiocarbon As a Poc Storage Tracersupporting

confidence: 81%

Model predictions of long-lived storage of organic carbon in river deposits

et al. 2017

View full text Add to dashboard Cite

show abstract

“…To address this question, another possible approach consists in investigating past continental environments through the study of marine or floodplain deposits. However, because in large river systems sediment transport and storage operates over >10 4 yr timescales (Granet et al, 2010), a significant time lag may exist between the time when sediments acquired their geochemical characteristics, reflecting palaeoenvironmental conditions, and their final deposition.Here we use the lithium (Li) isotopic composition of clays from sedimentary records in Himalayan basins to determine how chemical weathering intensity has varied over the past 40 ka and particularly since the Last Glacial Maximum (locally older than 24 ka; Owen et al, 2002). In order to minimise the time lag between source and deposit locations, we have focused on alluvial deposits located in the headwater areas of the Ganges and Yamuna Rivers.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Rapid response of silicate weathering rates to climate change in the Himalaya

Dosseto¹,

Vigier²,

Joannes‐Boyau³

et al. 2015

Geochem. Persp. Let.

Self Cite

View full text Add to dashboard Cite

11(<100 yr) to climate change and may act as a key component in the atmospheric CO 2 level short-term regulation (Beaulieu et al., 2012). However, the relative role of climatic parameters on chemical weathering is still debated. Model simulations and geochemical studies of river-born material highlight either a temperature dependence (Walker et al., 1981), where warming promotes chemical weathering, or a predominance of other parameters like mechanical erosion (Raymo and Ruddiman, 1992;Gaillardet et al., 1999;Riebe et al., 2001;Donnadieu et al., 2004) and vegetation (Bayon et al., 2012). To address this question, another possible approach consists in investigating past continental environments through the study of marine or floodplain deposits. However, because in large river systems sediment transport and storage operates over >10 4 yr timescales (Granet et al., 2010), a significant time lag may exist between the time when sediments acquired their geochemical characteristics, reflecting palaeoenvironmental conditions, and their final deposition.Here we use the lithium (Li) isotopic composition of clays from sedimentary records in Himalayan basins to determine how chemical weathering intensity has varied over the past 40 ka and particularly since the Last Glacial Maximum (locally older than 24 ka; Owen et al., 2002). In order to minimise the time lag between source and deposit locations, we have focused on alluvial deposits located in the headwater areas of the Ganges and Yamuna Rivers.While little isotope fractionation occurs during mineral dissolution clay formation induces strong fractionations at low temperature, whereby 6 Li is preferentially incorporated into clays compared to 7 Li, resulting in a strong enrichment of 7 Li in waters (Burton and Vigier, 2011). Thus, it has been shown that the d 7 Li composition of natural waters can be used as a proxy for chemical weathering rates at the catchment scale, since the heaviest d 7 Li compositions in water are associated with the areas characterised by low catchment-wide silicate weathering rates (Fig. 1). Several studies have also shown that the d 7 Li composition of solid weathering products (i.e. soils, river sediments) is sensitive to chemical weathering conditions, where lower d7 Li values reflect more intensive leaching (Burton and Vigier, 2011).To evaluate the reliability of the records studied, we investigated three different regions of the Himalaya and its piedmont in India: the upper Yamuna River basin, the Alaknanda River basin and the Donga Fan (Fig. S-1). Depositional ages for the alluvial deposits reported here were previously constrained by optically-stimulated luminescence (OSL) dating and range from 9 to 41 ka (Singh et al., 2001;Ray and Srivastava, 2010). Both bulk sediments and clay-sized fractions were analysed for Li isotopes. In bulk sediments, mineralogical abundances and Sr isotopes were also measured (see Supplementary Information). et al., 1981;Berner et al., 1983), accounting for nearly half the consumption of atmospheric carbon diox...

show abstract

“…Such a relationship was observed along the Amazon river, and using the formalism developed by Vigier et al (2001), the transport time of the sediment could be estimated (see section Dating Surface and Sub-Surface Processes). Subsequent studies by Granet et al (2007Granet et al ( , 2010 have obtained similar results for Himalayan rivers, which suggest again that significant weathering takes place during transport. One potential caveat of this method is the effect of 230 Th adsorption onto particles during transport.…”

Section: Sediment Transport Timementioning

confidence: 55%

“…This approach was extended by Granet et al (2010) to studies of different size fractions of sediments, and it was shown that the small grain size sediment travel faster than the coarser grain, as expected.…”

mentioning

confidence: 78%

U-Series Dating

Bourdon

2014

Encyclopedia of Scientific Dating Methods

View full text Add to dashboard Cite

U-series disequilibria in suspended river sediments and implication for sediment transfer time in alluvial plains: The case of the Himalayan rivers

Cited by 82 publications

References 38 publications

Model predictions of long-lived storage of organic carbon in river deposits

Model predictions of long-lived storage of organic carbon in river deposits

Rapid response of silicate weathering rates to climate change in the Himalaya

U-Series Dating

Contact Info

Product

Resources

About