Late Pleistocene Stratigraphy and Chronology in Southwestern British Columbia and Northwestern Washington
Late Pleistocene Stratigraphy and Chronology in Southwestern British Columbia and Northwestern Washington
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不列颠哥伦比亚省西南部和华盛顿西北部的晚更新世地层学和年代学
DOI：
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发表时间：
1965
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影响因子：
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通讯作者：
J. Noble
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文献类型：
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作者：
J. Armstrong;D. R. Crandell;D. Easterbrook;J. Noble
本文提出了不列颠哥伦比亚省西南部和华盛顿西北部晚更新世层序的六个地质气候单元。它们包括两个主要单元，奥林匹亚间冰期和弗雷泽冰川，以及后者的四个分区-埃文斯溪，瓦松和苏马斯体育场，以及艾弗森间体育场。奥林匹亚间冰期（Olympia Interglaciation）是一个非冰期事件，至少开始于36，000年前，一直持续到弗雷泽冰期（Fraser Glaciation）期间科迪勒纳冰川的推进。在埃文斯溪体育场，高山冰川形成在西部华盛顿和不列颠哥伦比亚省的山区，而非冰川沉积物仍在南部普吉特低地沉积。不列颠哥伦比亚省冰川的进一步增长导致了科迪勒拉冰盖的形成。这些冰在公元前25，000年后进入该地区的北方，但直到公元前15，000年后才到达南端。弗雷泽冰川的瓦松体育场开始于科迪勒拉冰川向低地的推进。它以海洋和冰川海洋条件的开始而结束，这些条件开始于Puget南部的低地，大约13，500年B. P.，以及格鲁吉亚海峡，大约13，000年B. P.。海洋条件代表的事件被称为Everson Interstade，持续了大约2000年，在此期间海洋包含了大量的浮冰。当陆地相对于海平面上升，迫使华盛顿西北部和不列颠哥伦比亚省西南部的大部分地区的海水退缩和浮冰消失时，Interstade结束;在弗雷泽低地的东部，这一事件与Sumas Stade期间山谷冰川的前进相吻合。
Six geologic-climate units are proposed for the late Pleistocene sequence in southwestern British Columbia and northwestern Washington. They include two major units, the Olympia Interglaciation and the Fraser Glaciation, and four subdivisions of the latter—the Evans Creek, Vashon, and Sumas Stades, and the Everson Interstade. The Olympia Interglaciation is a nonglacial episode that started at least 36,000 years B.P. and continued until the advance of Cordilleran glacier ice during the Fraser Glaciation. During the Evans Creek Stade, alpine glaciers formed in the mountains of western Washington and British Columbia while nonglacial sediments were still being deposited in the southern Puget Lowland. Further growth of glaciers in British Columbia resulted in the formation of the Cordilleran ice sheet. This ice entered the northern end of the area after 25,000 years B.P. but did not reach the southern end until after 15,000 years B.P. The Vashon Stade of the Fraser Glaciation began with this advance of Cordilleran ice into the lowlands. It ended with the beginning of marine and glaciomarine conditions there, which commenced in the southern Puget Lowland about 13,500 years B.P. and in the Strait of Georgia about 13,000 years B.P. The episode represented by the marine conditions is called the Everson Interstade and lasted about 2000 years, during which the sea contained much floating ice. The Interstade ended when the land rose with respect to the sea level forcing withdrawal of the sea and the disappearance of floating ice in most of northwestern Washington and southwestern British Columbia; in the eastern part of the Fraser Lowland this event coincided with the advance of a valley glacier during the Sumas Stade.