Geodynamik und Vulkanismus im tropischen/subtropischen Atlantik (Koordinatorantrag M64)

本次研究的总体目标是：(1)深入了解缓慢扩张的大西洋中脊（MAR）的火山和构造动力学以及活跃热液喷口区域的地球化学和生物过程，重点关注时间和空间变化；(2)将热液过程与火山活动联系起来。4 ~ 11°S之间的MAR在形态、熔体产生和岩浆成分上变化很大，是研究壳幔岩浆运移和火山喷发过程的理想区域。研究裂谷扩展、岩脉侵入和火山活动的演化，为了解热液喷口的形成演化及相关生物过程提供基础。在地质和生物学方面，南马尔盆地的研究要比北马尔盆地少得多。然而，已经发现了热液喷涌和富气流体发生的迹象。在这些数据的基础上，课题组将选择两个热液活跃点，并对其进行火山学、地球化学和生物学表征。流体地球化学和微生物学的离散目标是与北部MAR系统的比较，以及研究与相关微生物和动物群相关的流体相分离与水深的关系。从动物学的角度来看，南部MAR作为印度洋和太平洋之间可能的联系，在生物地理学和热液动物群演化方面的作用特别令人感兴趣。该项目的跨学科方法将为缓慢传播轴上的耦合过程和动力学提供新的见解。M64/2 （FL Villinger）这次巡航的调查是2004年在北纬15度大西洋中脊开始的计划的延续（巡航M60/3和各自的提案）。在2004年的巡航中，在北纬15°的Logatchev油田进行了基本的地球化学和生物学研究，2005年巡航的重点是在选定的热液喷口地点进行流体散发、流体温度和化学、微生物活动和相关动物群的时间变化。为了评估洛加乔夫热液区热液活动的长期变化，将安装若干环境监测站，这些监测站将于2006年恢复。2004年在Logatchev油田取样的流体可能为超临界流体（100 ~ 300 bar, 100 ~ 400℃），铁、甲烷和氢含量高，硫化物含量低，为热液栖息地提供了非常特殊的环境。2005年将重点研究不同喷口喷发点的地球化学变化及其对热液生态系统的影响。由于迄今为止对复杂热液系统的中期变化所知甚少，计划在今后几年继续进行这些与时间有关的研究。这个跨学科项目的优势在于地球化学、生物学和微生物学不同工作组之间的密切互动，这些工作组处理热液生态系统的不同层次（从流体的无机物质到不同的生命形式）以及这些层次之间的界面。

M64/1 (FL Haase) The overall goals of the investigation are (1) to obtain insight into the volcanic and tectonic dynamics of the slow-spreading Mid-Atlantic Ridge (MAR) and geochemical and biological processes at active hydrothermal vent areas with emphasis on variations in time and space, and (2) to link the hydrothermal processes to the volcanic activity on the axis. The MAR between 4 and 11°S is highly variable in morphology, melt production and magma composition and an ideal region to study magma transport in the crust and mantle as well as volcanic eruption processes. The evolution of rift propagation, dyke intrusion, and volcanic activity will be investigated which will provide a basis to understand the formation and evolution of the hydrothermal vents and associated biological processes. The southern MAR is geologically and biologically much less well investigated than the northern MAR. However, indications for the occurrence of hydrothermal venting of hot and gas-rich fluids have been found. On the basis of these data, our research group will select two hydrothermally active sites and characterize them volcanologically, geochemically and biologically. Discrete aims for the fluid geochemistry and microbiology are the comparison with northern MAR systems and the investigation of water-depth dependant phase separation of the fluids in relation to the associated microorganisms and fauna. From the zoological perspective, the role of the southern MAR for biogeography and evolution of hydrothermal fauna as a possible link between the Indian and Pacific Ocean is of special interest. The interdisciplinary approach of this project will provide new insight into the coupled processes and dynamics on a slow-spreading axis. M64/2 (FL Villinger) The investigations of this cruise are a continuation of the program started at 15°N on the Mid-Atlantic Ridge in 2004 (cruise M60/3 and respective proposals). While in the 2004 cruise basic geochemical and biological studies were carried out in the Logatchev field at 15°N, the emphasis of the 2005 cruise lies on the temporal variability of fluid emanations, fluid temperature and chemistry, microbial activities and associated fauna at selected hydrothermal vent sites. In order to assess longterm variations in hydrothermal activity of the Logatchev Hydrothermal Field, a number of environmental monitoring stations will be installed which will be recovered in 2006. The fluids sampled at the Logatchev field in 2004 are probably of supercritical (>300 bar, >400°C) origin, showed high iron, methane and hydrogen concentrations, but low sulfide contents, thus providing a very special environment for hydrothermal habitats. The geochemical changes at different vent emanation sites and their consequences for the hydrothermal ecosystem will be in the focus of the studies in 2005. As little is known so far about the medium-term variability of complex hydrothermal systems, it is planned to continue these time-dependant studies in the following years. The strength of this interdisciplinary project is the intense interaction of the different working groups of geochemistry, biology and microbiology, which address the different levels of the hydrothermal ecosystem (from the inorganic material of the fluids to the different life forms) and the interfaces between these levels.