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

这个资助项目的主要目的是测试关于大陆地壳起源的想法和对俯冲带火山弧输出的基本控制。西阿留申群岛含有高镁安山岩，其化学性质与平均大陆地壳非常接近。该奖项将支持阿留申弧线的现场疏浚项目，阿留申弧线是一个很好的自然实验室，因为它从未被撕裂，并显示出从东到西的辐合角梯度，在西部有强烈的斜辐合。此外，沉积物“通量”沿弧线呈梯度，西阿留申群岛代表全球低含沙量的一端。该计划旨在从阿留申弧西部的五个不同的疏浚区域获得更多的火山岩样本。将进行为期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测量和SCS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定年的费用。

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.