Collaborative Research: Primitive Magmatism and Crustal Genesis in an Island Arc

这一资助项目的主要目标是检验关于大陆地壳起源和对俯冲带火山弧输出的基本控制的想法。阿留申西部含有高镁安山岩，其化学成分与平均陆壳非常接近。这一奖项将支持在阿留申弧区进行现场疏浚的计划，这是一个很好的天然实验室，因为它从未被裂谷，并显示出从东到西的汇聚角梯度，在西部具有强烈的斜向会聚。此外，沿弧形的沉积物“通量”有一个梯度，阿留申群岛西部代表全球低沉积物含量的末端成员。该计划的目的是在五个不同的挖泥区从阿留申西部弧区获取更多火山岩样本。将进行30-35天的多波束、单通道地震和采样巡航(总共35-40艘挖泥船)，在采样之前进行水深和南海调查。预算包括一个最小的港口巡航分析项目和火成岩40Ar/39Ar测年的费用。

The main goals of this funded project are to test ideas about the origin of continental crust and the basic controls on the volcanic arc output of subduction zones. The western Aleutians contain high Mg# andesites that are very close in chemistry to the average continental crust. This award will support a field program of dredging in the Aleutian arc which is a good natural laboratory because it has never been rifted and shows a gradient of convergence angle from east to west, with strongly oblique convergence in the west. Further, there is a gradient in sediment "flux" along the arc, with the western Aleutians representing a global low-sediment content endmember. The program is aimed at obtaining more volcanic rock samples from the western Aleutian arc in five distinct dredge areas. A 30-35 day multibeam, single channel seismic and sampling cruise (35-40 dredges total) will be undertaken, with bathymetric and SCS surveys prior to sampling. The budget includes costs for a minimal port-cruise program of analyses and 40Ar/39Ar dating of igneous rocks.