Collaborative Research: Geothermal Fluxes of Solutes, Heat, and Carbon Dioxide to the River System of Central Nepal

尼泊尔中部纳拉亚尼河水系主要支流的温泉和溪流化学的综合研究，以及相关热液脉状物质的稳定同位素和流体包裹体研究正在进行中。喜马拉雅河溶质和沉积物来源的资料表明，中央主冲断带附近和塔科拉地块附近的活动地热系统是热源和溶质(包括Na、K、Ca、Cl、Ge、Si和Sr)的重要来源，从深部13C处的变质脱碳反应中释放出CO2，温泉流体的值高达+130/00，表明CO2的变质来源。在与三里苏利河交汇处，约25%的溶解K和Sr、12%-15%的溶解Si和90%的Cl来自MCT附近的热液来源。在马尔桑迪盆地高喜马拉雅结晶系列地区，地表泉水的平均热损失接近80mW/m2。这一数据表明，沿MCT的地热活动对喜马拉雅山脉的地球化学和热通量有重要影响。来自纳拉亚尼河主要支流(卡利·甘达基、塞提、马尔桑迪、布里和特里苏利河)的温泉和支流的数据被用来建立热液系统的化学和水质量平衡。保守示踪剂包括SO4/=Cl-和Ge/Se的化学质量平衡将被用来估计水热对河流通量的贡献。未变形的流体包裹体和稳定同位素分析对河流通量的贡献。流体包裹体和未变形的“后变质”石英和方解石脉的稳定同位素分析将被用来估计对流系统中的储层条件、水岩比和局部地温梯度。这项研究将提供重要的数据驱动的喜马拉雅地热流动和碳脱气估计，这将有助于解决目前喜马拉雅河对放射性成因锶和其他溶解物种的预算困难，并对我们对喜马拉雅构造过程及其如何影响地球化学通量的知识有了新的理解。

0090116DarlingIntegrated study of hot spring and stream chemistry in major tributaries of the Narayani river system of central Nepal, and stable isotope and fluid inclusion studies of associated hydrothermal vein material is underway. Data on the sources of solutes and sediments in Himalayan rivers indicate that active geothermal systems near the Main Central Thrust and in the Thakola graben are important sources of heat and solutes (including Na, K, Ca, Cl, Ge, Si and Sr), and release CO2 from metamorphic decarbonation reactions at depth 13C values from hot spring fluids are as high as +130/00, indicating a metamorphic source of CO2. About 25% of the flux of dissolved K and Sr, 12-15% of dissolved Si, and 90% of Cl at the confluence with the Trisuli river are derived from hydrothermal sources near the MCT. The heat loss from the surface springs is near 80 m W/m2 averaged over the area of the High Himalayan Crystalline series in the Marsyandi basin.This data indicate that geothermal activity along the MCT has a significant impact on geochemical and heat fluxes in the Himalaya.Data from hot springs and tributaries in the major tributary drainage of the Narayani (Kali Gandaki, Seti, Marsyandi, Bhuri, and Trisuli rivers) are being used to construct a chemical and water flux mass balance for the hydrothermal systems. Chemical mass balance of conservative tracers including SO4 /=Cl- and Ge/Se will be used to estimate hydrothernal contributions to river fluxes. Fluid inclusion and stable isotope analysis of undeformed "contribution to river Fluxes. Fluid inclusion and stable isotope analysis of undeformed "post-metamorphic" quartz and calcite veins will be used to estimate reservoir conditions, water-rock ratios, and local geothermal gradients in the convective system. The study is providing important data-driven estimate of geothermal heat flow and carbon degassing from the Himalaya that will help resolve difficulties with current Himalayan river budgets for radiogenic Sr and other dissolved species and new understanding to both our knowledge of Himalayan tectonic processes and how they impact geochemical fluxes.