Tectonic Setting and Uplift History of Metamorphic Rocks, Kigluaik Mountains and Vicinity, Seward Peninusla, Alaska

在阿拉斯加苏厄德半岛，以白垩纪花岗岩为核心的高温-低温-中压变质岩呈圆顶状隆起，两侧为高压-低温侏罗纪蓝片岩。这些杂岩的成因和构造背景一直存在争议，它们的隆升被认为是地壳增厚后的热松弛作用。初步的新工作表明，基格鲁克山的变形、变质和岩浆活动模式与盆地和岭省新生代变质核杂岩相似。野外填图、构造分析和年代学/热年代学研究将阐明苏厄德半岛蓝片岩隆升的时间和机制。集中研究的领域包括：暴露的最高结构水平；弱变质古生代岩与下方绿片岩至蓝片岩相岩之间的低角度断裂；以及圆顶的高温核心岩石。该方法还将确定隆升是单期还是多期。研究结果将涉及阿拉斯加北部蓝片岩相岩的年龄、区域构造背景和隆升，并将解决导致白令海和楚科奇海下近海陆架区域的可能伸展历史。这些结果还将提供对地壳中岩浆作用、变质作用和应变之间相互作用的见解，这些区域经历了巨大的垂直隆起。

Dome-shaped uplifts of high temperature-low to medium pressure metamorphic rocks with cores of Cretaceous granite are flanked by high pressure-low temperature Jurassic (?) blueschists in the Seward Peninsula of Alaska. The origin and tectonic setting of these complexes is controversial, and their uplift has been attributed to thermal relaxation following crustal thickening. Preliminary new work in the Kigluaik Mts. indicates patterns of deformation, metamorphism and magmatism that are similar to those in Cenozoic metamorphic core complexes of the Basin and Range province. Field mapping, structural analyses, andgeochronologic/ thermochronolgoic studies will elucidate the timing and mechanism of uplift of the blueschists rocks on Seward Peninsula. Areas of concentrated study include: the highest structural levels exposed; low angle faults between feebly metamorphosed Paleozoic rocks and greenschist to blueschist facies rocks beneath; and the high temperature core rocks of the domes. This approach will also establish whether uplift was single or multi-stage. The results will bear on the age, regional tectonic setting, and uplift of blueschist facies rocks in N. Alaska and will address the possible history of extension leading to the offshore shelf region beneath the Bering and Chukchi Seas. The results will also provide insight on the interplay between magmatism, metamorphism and strain in regions of the crust that undergo large vertical uplift.