Temporal evolution of hydrothermal systems at the Mid-Atlantic Ridge (14°45 - 15°05N)

洋中脊的热液活动是地幔与海洋之间传热传质的重要因素。关于热液系统的寿命、它们的时间变异性或热液溶液的化学性质随时间的变化的资料很少。在利用天然放射性核素测定热液矿床年龄的基础上，研究了Logatchev油田热液活动的持续时间和周期性，并首次研究了大西洋中脊15°N热液油田的热液活动，这些热液活动是由超基性岩石的蛇纹岩化引起的。根据地球化学和热液矿床的年龄，将获得地质历史时期热液流体变化的信息。本文以Logatchev油田的不同流体喷发为研究对象，探讨了热液流体在地壳中停留时间对其化学组成的重要性。这些研究是基于流体和热液沉淀的采样，这些采样将在FS流星巡航M60/3沿着14°45 N和15°05 N之间的大西洋中脊进行。

Hydrothermal activity at mid-oceanic ridges is an important factor for the heat and mass transfer between the mantle and the ocean. Little information is available on the life-span of hydrothermal systems, their temporal variability or changes of the chemistry of hydrothermal solutions with time. Based on age determinations of hydrothermal deposits by means of natural radionuclides, the duration and periodicity of hydrothermal activity shall be investigated in the Logatchev field and, for the first time, in hydrothermal fields at 15°N at the Mid-Atlantic Ridge, which are due to serpentinization of ultramafic rocks. Based on the geochemistry and the ages of the hydrothermal deposits information on the variability of the hydrothermal fluids during the geological past will be obtained. The importance of the residence time of hydrothermal fluids in the crust for their chemical composition will be investigated for the different fluids venting at the Logatchev field. These studies are based on sampling of fluids and hydrothermal precipitates which will be conducted during the FS Meteor cruise M60/3 along the Mid-Atlantic Ridge between 14°45 N and 15°05 N.