Quaternary Stratigraphy and History, Quesnel, British Columbia
Quaternary Stratigraphy and History, Quesnel, British Columbia
复制标题
第四纪地层学和历史，克内尔，不列颠哥伦比亚省
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
J. Clague
中科院分区：
文献类型：
--
作者：
J. Clague
在不列颠哥伦比亚省的奎斯奈尔发现了一层厚厚的第四纪沉积物，记录了前科洛尼亚冰盖中心附近地区第四纪晚期的历史。这些沉积物，部分，填补溪谷削减前的某个时候晚威斯康星弗雷泽冰川。特别值得注意的是：（1）由加积河流沉积的河流或冰川河流砂和砾石，可能部分是在弗雷泽时代早期;（2）较厚的冰川湖泥、砂和杂岩，是后来冰川穿过不列颠哥伦比亚省中部时沉积的;（3）类似于（2）的冰川湖沉积物，但沉积在弗雷泽冰川作用末期的冰坝湖中。地层被崩积物打断，崩积物是第四纪晚期不同时期谷壁滑坡的产物;这一过程一直持续到现在。在弗雷泽冰川作用期间，海岸和卡里布山脉的冰川合并并向北流过不列颠哥伦比亚省中部。弗雷泽冰川的提前沉积物和更古老的更新世沉积物部分被这个冰盖和被侵蚀的残余物覆盖着冰碛物。在这次冰川作用结束时，科洛尼亚冰盖向下萎缩，并沿沿着一条不规则的锋面向南退缩。大量的沉积物沉积在冰川湖中，这些冰川湖是由向南退缩的冰形成的。随着内陆冰川完全消退，冰湖排水，建立了现在的排水系统。起初，山谷部分地被沙子和砾石加积，但后来，河流切割山谷填充物，在连续较低的水平上产生一系列阶地。
Thick Quaternary sediments at Quesnel, British Columbia, provide a record of the late Quaternary history of an area near the centre of the former Cordilieran Ice Sheet. These sediments, in part, fill stream valleys that were cut sometime prior to the Late Wisconsinan Fraser Glaciation. Of special note are (1) fluvial or glaciofluvial sand and gravel deposited by aggrading streams, perhaps in part during early Fraser time; (2) thick glaciolacustrine mud, sand, and diamicton laid down later as glaciers advanced across central British Columbia; and (3) glaciolacustrine sediments similar to (2), but deposited in an ice-dammed lake at the end of the Fraser Glaciation. The stratigraphy is punctuated by colluvial deposits that are products of landslides from valley walls at various times during the late Quaternary; this process continues to the present. During the Fraser Glaciation, glaciers from the Coast and Cariboo Mountains coalesced and flowed north over central British Columbia. Fraser Glaciation advance sediments and older Pleistocene deposits were partially removed by this ice sheet and the eroded remnants mantled with till. At the end of this glaciation, the Cordilieran Ice Sheet downwasted and receded southward along an irregular front across the study area. Large amounts of sediment were deposited in glacial lakes dammed by the southward-retreating ice. With complete deglaciation of the interior, glacial lakes drained and the present drainage system was established. At first, valleys were partially aggraded with sand and gravel, but later, streams dissected valley fills to produce a series of terraces at successively lower levels.