Thermal anomalies associated with forced and free ground-water convection in the Dead Sea rift valley
Thermal anomalies associated with forced and free ground-water convection in the Dead Sea rift valley
复制标题
死海裂谷中与强迫和自由地下水对流相关的热异常
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
G. Gvirtzman
中科院分区：
文献类型：
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作者：
H. Gvirtzman;G. Garven;G. Gvirtzman
死海裂谷是一个左行转换带，沿着形成多个菱形地堑。在加利利海，这是这些菱形地堑之一，测量到模糊的热通量：在湖的中心部分为70 - 80 mW/m 2，在湖的南部海岸（相距10公里）为36 mW/m 2，最令人惊讶的是，在地堑边缘以东6 - 8公里的戈兰高地南部约为135 mW/m 2。绘制了一幅详细的地质剖面图，它横贯整个沉积盆地。在这个横截面的流体动力学进行了定量分析，使用二维有限元代码，解决耦合的变密度地下水流和传导对流传热方程。在数值模拟的基础上，盆地尺度的地下水对流的不同机制，可能会影响热量的传输：（1）从较深的含水层热卤水的强制对流（重力驱动流）的陆面在西部一侧;（2）大规模的自由对流（浮力驱动流）的深层地下水在东部一侧。裂谷内不同的热通量归因于不同的岩性和特定管道的位置，通过这些管道，热的地下沃茨从更深的地平线上升。这些模拟也解释了裂谷两侧温泉的不同盐度。
The Dead Sea rift valley is a left-lateral transform, along which several rhombshaped grabens were formed. At the Sea of Galilee, which is one of these rhomb-shaped grabens, ambiguous heat fluxes were measured: 70‐80 mW/m 2 at the central part of the lake, 36 mW/m 2 at the lake’s southern coast (10 km apart), and most surprising, about 135 mW/m 2 at the southern Golan Heights, 6‐8 km east of the graben margin. A detailed geologic cross section, traversing the entire sedimentary basin, was constructed. The hydrodynamics in this cross section were analyzed quantitatively using a two-dimensional finite element code that solves the coupled variable-density ground-water flow and conductive-convective heat transfer equations. On the basis of numerical simulations, different mechanisms of basin-scale groundwater convection are suggested for the two sides of the rift that could influence the transport of heat: (1) forced convection (gravitydriven flow) of hot brines from deeper aquifers to the land surface at the western side; and (2) large-scale free convection (buoyancy-driven flow) of deep ground water at the eastern side. The different heat fluxes within the rift valley are attributed to the different lithologies and to the locations of specific conduits through which the hot ground waters ascend from deeper horizons. These simulations also explain the different salinities of the hot springs on the two sides of the rift.