Pre-site survey for potential new ICDP sites in southern Patagonia (Argentina)

我们建议在1至2 Ma的老maar拉古纳Potrok Aike对计划中的ICDP取芯点（计划用于GLAD 200系统）进行气枪地震勘测，并在巴塔哥尼亚（阿根廷）南部的Meseta Cerro科罗拉多火山区对迄今未研究的火山口湖进行现场前勘测。以前和正在进行的调查，在拉古纳Potrok艾克承诺一个长期和未受干扰的沉积物记录，可能跨越几个冰川/间冰期周期的南半球中纬度地区至今尚未确定。根据3.5千赫的地震勘测，发现了一个厚度超过30-40米的水平层状远洋沉积物体。对长达17米的沉积物进行的短活塞式取芯提供了有关全新世水分平衡变化的数据，这些数据对目前依赖水的养羊经济具有重要价值。最大沉积物厚度最终需要用于提议新的ICDP钻探场地，并将通过气枪地震来实现。为了优化财政资源的使用，我们还将利用这次实地考察对Meseta Cerro科罗拉多的水深测量、物理和化学湖沼学、现代花粉和硅藻以及表层沉积物进行现场前调查，以便可能提出适合作为ICDP取样点的第二个湖泊，从而生成南北向样带。

We propose to carry out an airgun seismic survey for the planned ICDP coring site (scheduled for the GLAD200 system) at the 1 to 2 Ma old maar Laguna Potrok Aike and a pre-site survey of so far unstudied crater lakes in the volcanic area of the Meseta Cerro Colorado, both in southern Patagonia (Argentina). Previous and ongoing investigations at Laguna Potrok Aike promise a long and undisturbed sediment record that might span several glacial/interglacial cycles unidentified for midlatitudes of the southern hemisphere until now. Based on a 3.5 kHz seismic survey a horizontally layered body of pelagic sediments with a thickness exceeding 30-40 m was recognized. Short and piston coring of up to 17m of sediment provide data about Holocene variabilities of the moisture balance - data which is of great value for the prevailing water-dependent sheep farming economy. The maximum sediment thickness is ultimately needed for proposing a new ICDP drilling site and will be achieved by airgun seismic. To optimize the use of financial resources we will use this field trip also for a pre-site survey for bathymetry, physical and chemical limnology, modern pollen and diatoms and surface sediments in the Meseta Cerro Colorado to perhaps come up with a second lake suitable as ICDP coring site thus generating a north-south transect.