87Sr/86Sr as an indicator of flowpaths and weathering rates in the Plynlimon experimental catchments, Wales, U.K.
87Sr/86Sr as an indicator of flowpaths and weathering rates in the Plynlimon experimental catchments, Wales, U.K.
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DOI：
10.1016/j.chemgeo.2006.09.012
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发表时间：
2007-01
期刊：
影响因子：
3.9
通讯作者：
P. Shand;D.P. Fiona Darbyshire;D. Gooddy;Atul H. Haria
中科院分区：
文献类型：
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作者：
P. Shand;D.P. Fiona Darbyshire;D. Gooddy;Atul H. Haria
了解河流形成过程对了解高地集水区溶质运移和风化速率至关重要。在这种地形下，很难确定具体的水流路径和制定基于过程的模型，这主要是由于集水区的异质性和散装参数模型的必要限制。自然地球化学示踪剂已被证明是非常宝贵的，在发展概念模型的集水功能和约束风化过程和地球化学循环。锶同位素已被用作天然示踪剂，以计算锶和钙的风化率，并限制在两个高地森林的子流域（Afon Hafren和Afon霍尔）的河流塞文在Plynlimon在威尔士中部的主要流动途径。锶的主要来源在集水区被认为是从硅酸盐矿物的风化。风化率的Sr和Ca在Afon Hafren，使用Sr同位素计算，来自质量平衡研究。率的Afon霍尔是类似的钙，但显着不同的锶的差异的原因尚不清楚，但可能是由于额外的来源（方解石）在集水区。锶同位素比值的不同输入源和车厢内的集水区的特点，并帮助确定潜在的流动途径。数据表明，地下水输入的重要作用，与以往的模型，其中表明土壤沃茨的主导作用。
A knowledge of the processes involved in streamflow generation are critical to an understanding of solute transport and weathering rates in upland catchments. The determination of specific flow pathways and the formulation of process-based models have proved difficult in such terrains, largely due to the heterogeneous nature of catchments and the necessary limitations of bulked parameter models. Natural geochemical tracers have proved invaluable in developing conceptual models of catchment functioning and for constraining weathering processes and geochemical cycling. Strontium isotopes have been used as a natural tracer to calculate weathering rates for Sr and Ca, and to constrain the dominant flow pathways in two upland forested sub-catchments (Afon Hafren and Afon Hore) of the River Severn at Plynlimon in Central Wales. The dominant source of Sr in the catchments is considered to be from the weathering of silicate minerals. Weathering rates for Sr and Ca in the Afon Hafren, calculated using Sr isotopes, were similar to those derived from mass balance studies. The rates for the Afon Hore were similar for Ca, but significantly different for Sr. The reason for the difference is unclear, but may be due to additional sources (calcite) in the catchment. Strontium isotope ratios for different input sources and compartments within the catchment were characterised and helped to identify potential flow pathways. The data suggest an important role for groundwater inputs in contrast to previous models which indicated a dominant role for soil waters.