Hydrothermal Circulation on Sediment-Starved Mid-Ocean Ridges

目的是对发生在沉积物覆盖薄而不完整的年轻洋中脊侧翼的低温热液对流进行全面研究。现场项目将包括在大西洋中脊侧翼的三个不同年龄的沉积物池中进行转发器导航热流调查，以及孔隙压力测量，以确定流速和沉积物的原位水文特性。热流测量将沿每个池塘进行，并在异常附近进行额外的测量。活塞岩心将被用来测定物理性质，并将被保存下来，以供今后研究孔隙水化学。这些数据将用流体流动模型来解释。海洋地壳中的热液循环对地球的热收支和地壳与海洋之间的化学交换有深远的影响。对于发生在大洋中脊两侧的不完全覆盖的沉积物池的低温热液制度知之甚少。这个实地项目将是第一次详细观察海洋地壳中这一重要的热状态。

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.