Analysis of Sediment Areal Distribution in Laguna Potrok Aike (ASADO)

我们建议对(阿根廷)巴塔哥尼亚南部拉古纳波特罗克艾克的表层沉积物进行测绘。这将加深我们对现代马阿湖沉积物空间分布、沉积物地球化学特征和营养盐有效性控制过程的认识。鉴于ICDP深井钻探“波特罗克艾克玛尔湖沉积物档案钻探计划”(PASADO)的临近，这一知识对于彻底了解将从中央深湖盆地钻探的长沉积物记录至关重要。拟议的测绘项目将涵盖沉积物空间变异性的五个方面。(1)哪些沉积过程是重要的，是否有可能区分哪些颗粒经历了长时间的风沙输送？(2)沉积物剖面中的Fe/Mn比反映了氧化还原条件的变化。这些可以作为古湖平面变化的指标吗？(3)磷浓度的变化可能随着水深的不同而变化。高磷浓度的来源在哪里？这些变化如何影响湖泊生物群和碳酸盐降水？(4)稳定同位素值(13C)作为古海岸线接近程度的替代指标的有效性将得到检验。(5)将检查花粉是否均匀分布在整个湖上，并为所有调查的岩心位置提供可比较的信号。

We propose to carry out a mapping of surficial sediments in Laguna Potrok Aike, southern Patagonia (Argentina). This will bring forward our understanding of processes controlling the spatial sediment distribution, geochemical sediment characteristics and nutrient availability in a modern maar lake. In view of the approaching ICDP deep drilling “Potrok Aike Maar Lake Sediment Archive Drilling Program” (PASADO) this knowledge is vital for a thorough understanding of the long sediment record to be drilled from the deep central lake basin. With the proposed mapping project five aspects of spatial sediment variability will be covered. (1) Which depositional processes are important and is it possible to distinguish particles that have experienced long eolian transport? (2) Changes in redox conditions reflected by the Fe/Mn-ratio occur in the sediment profile. Can these be used as a proxy for palaeo lake level variations? (3) Changes in phosphorus concentration probably vary with water depth. Where is the origin of the high phosphorous concentration and how do these changes influence lake biota and carbonate precipitation? (4) The validity of stable isotope values (13C) as a proxy for palaeo-shoreline proximity will be tested. (5) It will be checked whether pollen are evenly distributed across the lake and provide a comparable signal for all investigated core positions.