阿拉斯加区域地质演化史  

The geologic evolution history of Alaska

作　　者：大卫.卡尔.施耐德 戴长雷[2,3] 杨朝晖[1] David K. Snyder DAI Changlei YANG Zhaohui(University of Alaska-Anchorage, Anchorage 99508, USA Institute of Groundwater in Cold Region, Heilongj iang University, Harbin 150080, China School of Hydraulic ＆ Electric-power, Heilongjiang University, Harbin 150080, China)

机构地区：[1]阿拉斯加大学安克雷奇分校,阿拉斯加州安克雷奇99508 [2]黑龙江大学寒区地下水研究所,黑龙江哈尔滨150080 [3]黑龙江大学水利电力学院,黑龙江哈尔滨150080

出　　处：《黑龙江水利》2016年第11期23-32,共10页

基　　金：中科院寒旱所冻土工程国家重点实验室开放基金项目(NO.SKLFSE201310);国家自然科学基金项目(NO.1202171)

摘　　要：地史图上包含着非常丰富的信息,通过研究阿拉斯加区域地质演化史有助于弄清楚中南阿拉斯加的地形地貌特征。在梳理地质年代的划分以及阿拉斯加地史图的基础上,对各时期阿拉斯加地质事件进行了分析。指出:(1)晚古生代时期的阿拉斯加存在的部分极少,都在非常温暖的纬度地区。亚历山大地体和兰格利亚地体正在北美克拉通西部的赤道附近形成。(2)晚三叠纪到早侏罗纪时期的阿拉斯加存在的部分不多,但是仅存在部分已随北美克拉通的其他部分向北移动。由4个独立的地体组成的兰格利亚复合体也已向北向东,朝着北美克拉通的方向迁移。(3)晚侏罗纪至早白垩纪时期的阿拉斯加,兰格利亚复合体靠近北美克拉通相当于现在加利福尼亚和俄勒冈附近的地区(当然,彼时它们还不存在)。北美洲本身移动到比现在的位置往北得多的地方。阿拉斯加北部地区开始分离并从加拿大北部开始旋转移动。(4)晚白垩纪时期的阿拉斯加,兰格利亚地体也已经贴附到阿拉斯加之上,这样就使得北美克拉通的西北部开始有了组装阿拉斯加的框架了。(5)始新世时期的阿拉斯加据信已与现在的形状非常相似。威廉王子地体和亚库塔特地体已由洋盆沉积物形成;德奈利断层以及其他断层已处于现在的位置;阿拉斯加的西部已向南旋转到当前的纬度位置。(6)中南阿拉斯加地史剖面系列图,标示了过去2.3亿年中南阿拉斯加地面以下地体活动状况。The geologic history map contains abundant information. Studying the geologic evolution history of Alaska can help further understand its landscape views. This paper analyzes geological events in Alaska on the basis of combing the division of geological time and the geologic history map of Alaska under the premise of knowledge. It points out. ①The few parts of Alaska that existed at Late Paleozoic were at much warmer latitudes. The Alexander and Wrangellia Terranes were forming near the equator, somewhere to the west of North America; ②Late Triassic to Early Jurassic Alaska barely exists yet, but has moved to the north with the rest of North America. The Wrangellia Composite Terrane, consisting of four separate terranes, has also moved northward and eastward, towards North America; ③Late Jurassic to Early Cretaceous Alaska. Wrangellia approaches North America in the vicinity of California and Oregon, which don＇t yet exist. North America itself has moved farther north than it is today. What will become northern Alaska begins to split and rotate away from northern Canada; ④Late Cretaceous Alaska.. Wrangellia has accreted onto Alaska, giving northwestern North America a shape that begins to resemble Alaska; ⑤By the Eocene, Alaska has assumed a familiar appearance. The Prince William and Yakutat Terranes have formed from the sediments of the ocean basins; the Denali Fault and others are in place; and the western part of Alaska is rotating southward towards its present latitude; ⑥The sequence of cross sections portrays what was happening beneath the surface of Southcentral Alaska as the terranes were accreting during the last 230 million years.

关 键 词：地质年代 地史图 地质体 地形地貌 阿拉斯加 

分 类 号：P54[天文地球—构造地质学]