Provenance of the Neogene to Holocene sediments drilled by IODP Expedition 341 in the Gulf of Alaska. A single grain geochemical and geochronological study of the glacially influenced denudation history of the evolving St. Elias Orogen using heavy mineral

拟议的案例研究调查了过去约10 Ma期间从地球上最高的沿海山带圣埃利亚斯造山带到阿拉斯加湾的大规模质量转移的时间和空间演变。目标是分别来自近端和远端测量扇上两个地点的沙子、淤泥和直径，这些都是在2013年IODP 341号探险过程中钻探的。应用的工具包括重矿物的单颗粒地球化学分析。角闪石、石榴石和锆石的初步地球化学数据表明，其来源主要是楚加赫地体。结合角闪石的40Ar-39Ar年龄和锆石的U-Pb年龄，可以限制陆上剥蚀和近海沉积之间的时间联系。在这里申请的第三个项目年，我们计划通过应用同一套工具对U1417站点近距离分布的样品进行高分辨率研究，集中研究中更新世过渡(MPT)期间的物源演化。MPT与圣埃利亚斯造山带的抬升和山带的加速侵蚀相吻合。这一高分辨率方法将提供详细的信息，帮助重建气候变化与重大气候过渡期间不断变化的侵蚀模式之间的关系。

The proposed case study investigates the temporal and spatial evolution of the large-scale mass transfer from the St. Elias Orogen, the highest coastal mountain belt on Earth, to the Gulf of Alaska over the last ca. 10 Ma. The targets are sands, silts and diamicts from two sites on the proximal and distal Surveyor Fan, respectively, drilled in the course of IODP Expedition 341 in 2013. The tools applied include single-grain geochemical analysis of heavy minerals. Initial geochemical data on hornblende, garnet and zircon point to a derivation mainly from the Chugach Terrane. The combination with U-Pb age dating of zircon with 40Ar-39Ar age dating of hornblende will allow for constraining the temporal link between onshore denudation and offshore deposition. In the 3rd project year applied for here we plan to concentrate on the provenance evolution during the Mid-Pleistocene Transition (MPT) by applying the same set of tools to a high resolution study of closely spaced samples of Site U1417. The MPT coincides with increased uplift of the St. Elias orogen and accelerated erosion of the mountain belt. This high-resolution approach will provide detailed information helping to reconstruct the relationship of climate change and changing erosion patterns across a major climate transition.