Assessing Weathering as a Function of Climate in Proximal Alluvial Sediments

评估近端冲积沉积物中风化作用与气候的关系Gerilyn Sorghan，Megan Elwood-Madden，1225162，俄克拉荷马大学摘要从沉积相推断冰川影响是难以捉摸的，特别是在缺乏冰接触指标的情况下（例如，条纹碎屑）。基于沉积相的冰川作用推断引发了关于从太古代的黑暗深处到更新世的沉积物和沉积岩的争论，这就说明了这一点。传统的化学风化指数也是模糊的，特别是在区分冰川/冰前冲积层从那些形成于炎热干旱系统。然而，综合化学，矿物学和纹理的观察，冲积沉积物形成的温度，降水极端可以提供有价值的气候指标的沉积研究，特别是在区分冰川和非冰川系统。 PI建议测试的假设，即大量的化学，纹理，矿物学，和花岗岩源冲积沉积物的溶质通量显示系统和强大的变化之间的冰川和非冰川系统由于反应表面积，温度和含水条件的差异。因此，拟议研究的目标是量化端元冰川和非冰川系统中花岗岩源近端冲积沉积物中化学和物理风化的自然变化，当其他“非气候”因素（例如，物源、流域面积和地貌、样品粒度、沉积相）。最终目标是建立一个化学和结构指标的定量矩阵，以区分在不同气候条件下形成的沉积物。

Assessing Weathering as a Function of Climate in Proximal Alluvial SedimentsbyGerilyn Sorghan, Megan Elwood-Madden, EAR-1225162, University of OklahomaABSTRACTInferring a glacial influence from sedimentary facies is elusive, especially in the absence of ice-contact indicators (e.g., striated clasts). Illustrating this, inferences of glaciation on the basis of sedimentary facies have ignited controversies for sediments and sedimentary rocks from the murky depths of the Archean through the comparable light of the Pleistocene. Traditional chemical weathering indices are also ambiguous, particularly in discerning glacial/proglacial alluvial deposits from those formed in hot-arid systems. However, integrating chemical, mineralogical, and textural observations of alluvial sediments formed in temperature-precipitation extremes could provide valuable indicators of climate for sedimentary studies, particularly in distinguishing glacial from non-glacial systems. PIs propose to test the hypothesis that bulk chemistry, texture, and mineralogy, and solute fluxes of granitoid-sourced alluvial sediments show systematic and robust variations between glacial and non-glacial systems owing to differences in reactive surface area, temperature, and aqueous conditions. Accordingly, the objective of the proposed research is to quantify natural variation of chemical and physical weathering in granitoid-sourced proximal alluvial sediments in end-member glacial and non-glacial systems when other, "non-climatic" factors (e.g., provenance, drainage basin area and relief, sample grain size, sediment facies) are controlled. The ultimate goal is to establish a quantitative matrix of chemical and textural metrics to differentiate sediments formed in contrasting climates.