More Like this

1. Assessing molybdenum isotope fractionation during continental weathering as recorded by weathering profiles in saprolites and bauxites

   https://doi.org/10.1016/j.chemgeo.2021.120103  

   Greaney, Allison T. ; Rudnick, Roberta L. ; Romaniello, Stephen J. ; Johnson, Aleisha C. ; Anbar, Ariel D. ; Cummings, Michael L. ( April 2021 , Chemical Geology)

   null (Ed.)
2. Concentration-runoff relationships of contrasting small mountainous rivers in the Pacific Northwest, USA: Insights into the weathering of rhenium relative to other weathering products

   https://doi.org/10.1016/j.gca.2022.09.036  

   Ghazi, Layla ; Goñi, Miguel ; Haley, Brian A. ; Muratli, Jesse M. ; Pett-Ridge, Julie C. ( November 2022 , Geochimica et Cosmochimica Acta)

   This study examines dissolved rhenium (Re) concentrations as a function of water runoff using river samples from two contrasting mountainous watersheds, the Eel and Umpqua Rivers in the Pacific Northwest, USA. These watersheds share many key characteristics in terms of size, discharge, climate, and vegetation, but they have a 15-fold difference in sediment yield due to differences in their tectonic setting and uplift and erosion rates. We evaluate concentration-runoff (C-R) relationships and ratios of coefficients of variation (CVC/CVR) for major cations, anions, dissolved inorganic carbon, selected trace elements including Re, and 87Sr/86Sr ratios. Recent research outlines the potential of Re to serve as a tracer for the oxidation of ancient/fossil organic matter because of its close association with petrogenic carbon (OCpetro) in rocks. In both the Eel and Umpqua Rivers, our measurements show that Re behaves similarly to major weathering derived-solutes corrected for atmospheric input, such as Ca2+*, Mg2+*, and Na+* with modest dilution across all tributaries with increasing runoff. Rhenium behaves dissimilarly from other trace elements, such as Mo and U, and is also dissimilar to biologically-cycled nutrients, such as NO3 – , PO4 3 , and K+*, suggesting differences in sources, solute generation mechanisms, and flowpaths. Rhenium behavior is also distinct from that of colloids, which have increasing concentrations with increasing runoff. We find that Re and sulfate corrected for atmospheric input (SO4 2 *) have distinct CR relationships, in which SO4 2 * undergoes greater dilution with increasing runoff. This implies that Re is not dominantly sourced from sulfide weathering, which leaves primary bedrock minerals and OCpetro hosted in bedrock of these watersheds as the likely dominant sources of dissolved Re release. At mean discharge, Re concentration in the Eel river (3.5 pmol L-1) is more than two times greater than Re concentrations in the Umpqua River (1.5 pmol L-1). Furthermore, comparison of two tributary watersheds with similar bedrock but marked differences in erosion rates show higher Re concentrations in Bull Creek (erosion rate of 0.5 mm yr 1) relative to Elder Creek (erosion rate of 0.2 mm yr 1). The results of this study suggest that dissolved Re in the Eel and Umpqua River basins is likely derived from primary mineral dissolution or OCpetro oxidation, and Re fluxes are higher in areas with higher erosion rates, suggesting that tectonic setting is one factor that controls Re release and therefore OCpetro oxidation. 

   more » « less
3. Reconciling chemical weathering rates across scales: Application of uranium-series isotope systematics in volcanic weathering clasts from Basse-Terre Island (French Guadeloupe)

   https://doi.org/10.1016/j.epsl.2019.115874  

   Guo, Jiye ; Ma, Lin ; Gaillardet, Jerome ; Sak, Peter B. ; Pereyra, Yvette ; Engel, Jacqueline ( January 2020 , Earth and Planetary Science Letters)
4. Investigating the role of anhydrous oxidative weathering on sedimentary rocks in the Transantarctic Mountains and implications for the modern weathering of sedimentary lithologies on Mars

   https://doi.org/10.1016/j.icarus.2018.10.007  

   Salvatore, M. ; Truitt, K. ; Roszell, K. ; Lanza, N. ; Rampe, E. ; Mangold, N. ; Dehouck, E. ; Wiens, R. ; Clegg, S. ( February 2019 , Icarus)
5. The effect of curvature on weathering rind formation: Evidence from Uranium-series isotopes in basaltic andesite weathering clasts in Guadeloupe

   https://doi.org/10.1016/j.gca.2011.11.038  

   Ma, Lin ; Chabaux, Francois ; Pelt, Eric ; Granet, Mathieu ; Sak, Peter B. ; Gaillardet, Jerome ; Lebedeva, Marina ; Brantley, Susan L. ( March 2012 , Geochimica et Cosmochimica Acta)