Hydrothermal Circulation on Sediment-Starved Mid-Ocean Ridges

目的对沉积物覆盖较薄且不完整的年轻大洋中脊侧翼发生的低温热液对流进行综合研究。现场计划将包括在中大西洋海脊两侧的三个不同年龄的沉淀池进行应答器导航的热流调查，以及测量孔压以确定沉积物的流速和现场水文特性。热流测量将在每个池塘沿线和跨池塘的剖面上进行，并在异常附近进行额外测量。活塞岩心将被用于确定物理性质，并将被保存下来，以供未来的孔隙水化学工作。这些数据将根据流体流动模型进行解释。洋壳中的水热循环对地球的热量收支和地壳与海洋之间的化学交换有着深远的影响。关于出现在大洋中脊两侧的未完全覆盖的沉淀池的低温热液状况，人们知之甚少。这一实地考察计划将是首次详细研究这一重要的洋壳热状况。

Objective is to make a comprehensive study of low temperature hydrothermal convection occurring in young mid- ocean ridge flanks where sediment cover is thin and incomplete. The field program will involve a transponder navigated heat flow survey in three sediment ponds of different ages on the flanks of the Mid-Atlantic Ridge, as well as pore pressure measurements to determine flow rates and in situ hydrologic properties of the sediment. Heat flow measurements will be made in a profile along and across each pond, with additional measurements in the neighborhood of anomalies. Piston cores will be taken for the determination of physical properties and will be preserved for future work on pore water chemistry. The data will be interpreted in terms of fluid flow models. %%% Hydrothermal circulation in the oceanic crust has a profound impact on the heat budget of the earth and on chemical exchange between the crust and the ocean. Little is known about the low temperature hydrothermal regime of incompletely covered sediment ponds that occur on the flanks of mid-ocean ridges. This field program will be the first detailed look at this important thermal regime in the oceanic crust.