Seamounts as Conduits for Massive Fluid, Heat, and Solute Fluxes on Ridge Flanks
Seamounts as Conduits for Massive Fluid, Heat, and Solute Fluxes on Ridge Flanks
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DOI：
10.5670/oceanog.2010.63
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发表时间：
2010-03-01
期刊：
影响因子：
2.8
通讯作者：
Wheat, C. Geoffrey
中科院分区：
文献类型：
--
作者：
Fisher, Andrew T.;Wheat, C. Geoffrey
海底山在促进海洋岩石圈和上覆海洋之间的流体、热量和溶质交换方面起着重要作用。全球热流汇编表明，由于来自地壳的流体流动，大部分海底损失了很大一部分岩石圈热量，而这种平流热量损失大部分发生在山脊两侧，远离海底扩张中心岩浆侵位的热影响。在地壳和海洋之间流动流体的驱动力是有限的，而且大部分海底被低渗透率沉积物覆盖，阻止了流体以显著的热速率垂直流动。因此，地壳和海洋之间大多数重要的热流体交换必须发生在海底火山岩暴露的地方；山脊两侧的少量流体交换通过火山地壳岩石上的海底沉积物发生。海山和其他基底露头集中了地壳和海洋之间的脊侧热液交换。我们描述了海脊两侧热液流动的驱动力，以及这些系统对地壳热损失、流体组成和海底微生物的影响。我们展示了从两个脊翼区域收集的数据，这些数据说明了流体交换、岩石圈热损失、化学反应和输送的程度如何取决于地壳水文系统中流体流动速率、流体停留时间和温度。海底山是对地壳流体进行取样的理想场所，当它们离开地壳进入海洋时，可以确定它们的化学和微生物特征，并评估这个全球水文地质系统对地球岩石圈、海洋和生物圈演化的重要性。
Seamounts play a fundamental role in facilitating the exchange of fluids, heat, and Solutes between the oceanic lithosphere and the overlying ocean. Global heat flow compilations indicate that Much of the seafloor loses a significant fraction of lithospheric heat because Of fluid flow from the crust, and most of this advective heat loss Occurs on ridge flanks, areas far from the thermal influence of magmatic emplacement at seafloor spreading centers. The driving forces available to move fluid between the crust and ocean are modest, and most of the seafloor is blanketed by low-permeability sediment that prevents vertical fluid flow at thermally significant rates. Thus, Most Of the thermally important fluid exchange between the crust and ocean must occur where volcanic rocks are exposed at the seafloor; little fluid exchange on ridge flanks Occurs through seafloor sediments overlying volcanic crustal rocks. Seamounts and other basement Outcrops focus ridge-flank hydrothermal exchange between the crust and the ocean. We describe the driving forces responsible for hydrothermal flows on ridge flanks, and the impacts that these systems have on crustal heat loss, fluid composition, and subseafloor microbiology. We show data collected from two ridge-flank areas that illustrate how the extent of fluid exchange, lithospheric heat loss, and chemical reaction and transport depend on the rate Of fluid flow, fluid residence time, and temperature in crustal hydrologic systems. Seamounts are ideal places to sample crustal fluids as they exit the crust and enter the ocean, to determine their chemical and microbial characteristics, and to assess the importance of this global hydrogeologic system on the evolution of Earths lithosphere, ocean, and biosphere.