Isotopic values of the Amazon headwaters in Peru: comparison of the wet upper Río Madre de Dios watershed with the dry Urubamba‐Apurimac river system

Lambs, Luc; Horwath, Aline B.; Otto, Thierry; Julien, Frédéric; Antoine, Pierre‐Olivier

doi:10.1002/rcm.6157

Cited by 13 publications

(15 citation statements)

References 31 publications

(51 reference statements)

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“…Because this complex behavior occurs at high runoff rates, it has an important impact on the total solute fluxes. Compared to the other sites, San Pedro has the highest annual precipitation (Lambs et al, 2012;Clark et al, 2014), which may be a factor contributing to its unique behavior at high runoff.…”

Section: The Effects Of Changes In Fluid Flow Paths On Concentration-mentioning

confidence: 95%

“…During the study period (2010-2011), annual rainfall was 2519 ± 3 35 mm year À1 and 3112 ± 414 mm year À1 for the Way and SP catchments respectively, slightly above the long-term average . Like air temperature, rainfall also shows a strong elevational dependence (Lambs et al, 2012;Clark et al, 2014). For the same 2010-2011 period, annual runoff was estimated to be 3065 mm year À1 and 2796 ± 126 mm year À1 for the Way and SP catchments respectively .…”

Section: Andean Sitesmentioning

confidence: 99%

“…Because the CICRA catchment incorporates both the Andes and foreland-floodplain region, temperature is heterogeneous throughout the catchment. Near the sampling locality, meteorological stations (data available from http://atrium.andesamazon.org) record temperatures that typically range from 21 to 26°C with a mean of $24°C and precipitation volumes that range from 2600 to 3500 mm/year, with mean values between 2700 and 3000 mm/year (Lambs et al, 2012). A majority of the annual rainfall in Peru occurs during the austral summer (Lambs et al, 2012;Clark et al, 2014).…”

Section: Foreland Floodplain Sitementioning

confidence: 99%

“…Near the sampling locality, meteorological stations (data available from http://atrium.andesamazon.org) record temperatures that typically range from 21 to 26°C with a mean of $24°C and precipitation volumes that range from 2600 to 3500 mm/year, with mean values between 2700 and 3000 mm/year (Lambs et al, 2012). A majority of the annual rainfall in Peru occurs during the austral summer (Lambs et al, 2012;Clark et al, 2014). The catchment area of CICRA is largely underlain by sediments shed from the Andes with additional contributions from Cretaceous marine sediments and Cenozoic continental deposits (Räsänen et al, 1992;Mendívil Echevarría and Dávila Manrique, 1994;Carlotto Caillaux et al, 1996;Vargas Vilchez and Hipolito Romero, 1998;INGEMMET, 2013).…”

Section: Foreland Floodplain Sitementioning

confidence: 99%

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Geomorphic regime modulates hydrologic control of chemical weathering in the Andes–Amazon

Torres

West

Clark

2015

Geochimica et Cosmochimica Acta

107

180

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The interplay between the hydrologic processes that supply, store, and route water in catchment systems and the chemical weathering reactions that add and remove solutes acts as an important control on chemical weathering fluxes. In this study, we use paired measurements of solute chemistry and runoff in four nested catchments that span the transition from the Andes Mountains to the Amazonian foreland floodplain in Peru in order to investigate the links between hydrology and weathering processes and to determine how these links change across a geomorphic gradient. All of the sites show variation in elemental concentrations and ratios with runoff consistent with hydrologically driven changes in lithologic sources, the extent of secondary mineral precipitation, and, potentially, fluid flow paths. In the Andean sites, solute concentrations are relatively constant despite large changes in runoff. This is in direct contrast to the foreland floodplain site, where solute concentrations are diluted as runoff increases. In the Andes-Amazon, the concentration-runoff behavior is correlated with the mean catchment slope angle, which suggests that erosional processes, by modulating the timescales over which weathering reactions occur within the critical zone, can be an underlying control on solute production and therefore on chemical weathering. Due to the co-variation between the geomorphic and hydrologic controls on chemical weathering, weathering fluxes in Andean sites are more sensitive to seasonal changes in runoff than in the foreland floodplain site.

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Section: The Effects Of Changes In Fluid Flow Paths On Concentration-mentioning

confidence: 95%

Section: Andean Sitesmentioning

confidence: 99%

Section: Foreland Floodplain Sitementioning

confidence: 99%

Section: Foreland Floodplain Sitementioning

confidence: 99%

See 2 more Smart Citations

Geomorphic regime modulates hydrologic control of chemical weathering in the Andes–Amazon

Torres

West

Clark

2015

Geochimica et Cosmochimica Acta

107

180

View full text Add to dashboard Cite

show abstract

“…Upland δD stream values (representative of meteoric water) show little seasonal variability, even though precipitation isotopes vary significantly on seasonal timescales (100‰ seasonal range in precipitation composition, see Horwath [] and Lambs et al . []). This lack of variability in upland δD stream can be explained by groundwater mixing [ Clark et al ., ].…”

Section: Effect Of Elevation On Hydrogen Isotopesmentioning

confidence: 99%

Leaf wax biomarkers in transit record river catchment composition

Ponton

West

Feakins

et al. 2014

Geophys. Res. Lett.

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Rivers carry organic molecules derived from terrestrial vegetation to sedimentary deposits in lakes and oceans, storing information about past climate and erosion, as well as representing a component of the carbon cycle. It is anticipated that sourcing of organic matter may not be uniform across catchments with substantial environmental variability in topography, vegetation zones, and climate. Here we analyze plant leaf wax biomarkers in transit in the Madre de Dios River (Peru), which drains a forested catchment across 4.5 km of elevation from the tropical montane forests of the Andes down into the rainforests of Amazonia. We find that the hydrogen isotopic composition of leaf wax molecules (specifically the C 28 n-alkanoic acid) carried by this tropical mountain river largely records the elevation gradient defined by the isotopic composition of precipitation, and this supports the general interpretation of these biomarkers as proxy recorders of catchment conditions. However, we also find that leaf wax isotopic composition varies with river flow regime over storm and seasonal timescales, which could in some cases be quantitatively significant relative to changes in the isotopic composition of precipitation in the past. Our results inform on the sourcing and transport of material by a major tributary of the Amazon River and contribute to the spatial interpretation of sedimentary records of past climate using the leaf wax proxy.

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Mixing as a driver of temporal variations in river hydrochemistry: 2. Major and trace element concentration dynamics in the Andes‐Amazon transition

Baronas

Torres

Clark

et al. 2017

Water Resources Research

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Variations in riverine solute chemistry with changing runoff are used to interrogate catchment hydrology and to investigate chemical reactions in Earth's critical zone. This approach requires some understanding of how spatial and temporal averaging of solute‐generating reactions affect the dissolved load of rivers and streams. In this study, we investigate the concentration‐runoff (C‐Q) dynamics of a suite of major (Na, Mg, Ca, Si, K, and SO4) and trace (Al, Ba, Cd, Co, Cr, Cu, Fe, Ge, Li, Mn, Mo, Nd, Ni, Rb, Sr, U, V, and Zn) elements in nested catchments of variable size, spanning the geomorphic gradient from the Andes Mountains to the Amazon Foreland‐floodplain. The major elements exhibit various degrees of dilution with increasing runoff at all sites, whereas the concentrations of most trace elements either increase or show no relationship with increasing runoff in the three larger catchments (160–28,000 km2 area). We show that the observed main stem C‐Q dynamics are influenced by variable mixing of tributaries with distinct C‐Q relationships. Trace element C‐Q relationships are more variable among tributaries relative to major elements, which could be the result of variations in geomorphology, lithology, and hydrology of the subcatchments. Certain trace metals are also lost from solution during in‐channel processes (possibly related to colloidal size‐partitioning), which may exert an additional control on C‐Q dynamics. Overall, we suggest that tributary aggregation effects should be assessed in heterogeneous catchments before C‐Q or ratio‐Q relationships can be interpreted as reflecting catchment‐wide solute generation processes and their relationship to hydrology.

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Isotopic values of the Amazon headwaters in Peru: comparison of the wet upper Río Madre de Dios watershed with the dry Urubamba‐Apurimac river system

Cited by 13 publications

References 31 publications

Geomorphic regime modulates hydrologic control of chemical weathering in the Andes–Amazon

Geomorphic regime modulates hydrologic control of chemical weathering in the Andes–Amazon

Leaf wax biomarkers in transit record river catchment composition

Mixing as a driver of temporal variations in river hydrochemistry: 2. Major and trace element concentration dynamics in the Andes‐Amazon transition

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