Quantifying crustal fluid flow and its role in the thermal structure of the Alps

热年代学是一个关键工具，它为我们提供了造山带如何随时间演化的大部分知识。对热年代学数据的解释依赖于对地下温度的独立估计。虽然许多控制温度的过程可以有一定程度的可信度进行建模，但地下水流动的热效应仍然高度不确定。尽管如此，几项研究表明，在活动造山带的部分地区，地下水可以占到总热量输送的50%。我们建议通过量化深部流体流动最明显的露头：温泉的热效应来量化流体流动对造山带热结构的重要性。我们的目标是汇编阿尔卑斯山的温泉数据，并使用逆热模型来量化与这些温泉相关的流体流动系统的热影响。我们将结合数值模型和露头和微观尺度的水文地质结构的详细绘图来量化选定数量的泉水的流体压力和流量。我们将把模型与补给和冰盖变化的独立数据结合起来，以量化热液系统在地质时间尺度上的持久性。这一结果将提供整个造山带尺度上深部流体流动及其对热场影响的第一幅图像。我们的结果将为造山过程的地球物理模型提供输入数据和约束，并将影响依赖于(古)地热梯度估计的热年代学研究。此外，流体压力在地震活动中起着重要作用，但由于缺乏钻孔数据，造山带中的流体压力在很大程度上是未知的。我们的结果将为地壳流体压力和渗透率提供新的约束条件，从而为新构造模型提供输入参数。

Thermochronology is a key tool that provides large parts of our knowledge of how orogens have evolved over time. The interpretation of thermochronological data relies on independent estimates of subsurface temperatures. While many processes that control temperature can be modelled with some degree of confidence, the thermal effects of groundwater flow remain highly uncertain. Nonetheless, several studies have demonstrated that in parts of active orogens groundwater can account for up to 50% of the overall heat transport. We propose to quantify the importance of fluid flow on the thermal structure of orogens by quantifying the thermal effects of the most visible outcrop of deep fluid flow: thermal springs. We aim to compile thermal spring data in the Alps and use inverse thermal models to quantify the thermal impact of the fluid flow systems that are associated with these springs. We will combine numerical models and detailed mapping of the hydrogeological structure at outcrop and micro-scale to quantify fluid pressures and flow for a selected number of springs. We will combine models with independent data on changes in recharge and ice cover to quantify the persistence of hydrothermal systems over geological timescales. The results will provide the first image of deep fluid flow and its effect on the thermal field at the scale of an entire orogen. Our results will provide input data and constraints for geophysical models of mountain building processes, and will impact thermochronological studies that rely on estimates of (paleo) geothermal gradients. In addition, fluid pressure plays an important role in seismic activity, but is largely unknown in orogens due to the absence of borehole data. Our results will provide new constraints on fluid pressures and permeability of the crust, and consequently provide input parameters for neo-tectonic models.