Tectonic Significance of Lower Cretaceous Gravels, Southern Canadian Rockies: Quantitative Models of Basin Development

PI将研究古地形，沉降和源 上侏罗统-下侏罗统区域开发史 白垩纪前陆层序沿着南部 加拿大哥伦比亚造山带的一部分及其邻近地区 蒙大拿州。 哥伦比亚/塞维尔带，标志着 晚中生代造山作用在北美的顶点 科迪勒拉山脉，一般是连续的沿着其长度和整体 在构造样式、时代和地层上都具有相似性 邻近前陆盆地的发育。 这两个地区都有 晚侏罗世，泥质为主的河流沉积， 古水流;下白垩统相对广泛分布的硅质卵石 坟墓;以及区域性的亚白垩纪不整合面，将 两个单位。 然而，这两个地区在以下细节上有所不同： 分布和古流向。 在 此外，对构造驱动力的解释也不一致 两条带之间的碰撞主要是 哥伦比亚带和岩浆活动 塞维尔腰带 通过定量分析南哥伦比亚前陆 序列，并将这些数据与我们以前的研究进行比较， 塞维尔前陆序列，我们将确定， 也记录了类似的进化历史 如果是这样，那么两个 哥伦比亚带和塞维尔带活跃的不同机制 产生了相同的地层记录 如果不是，那两个人 非常不同的推力带驱动机构产生这种 非常相似的地层包， 两个造山带之间的过渡地带？

PIs will study the paleotopographic, subsidence and source area development history of the Upper Jurassic to Lower Cretaceous foreland stratigraphic sequence along the southern part of the Columbian orogenic belt in Canada and adjacent parts of Montana. The Columbian/Sevier belt, which marks the culmination of Late Mesozoic orogency in the Norther American Cordillera, is generally continuous along its length and overall is similar in structural style, timing and stratigraphic development of the adjacent foreland basin. Both regions contain Upper Jurassic, mud-dominated fluvial deposits with easterly paleoflow; comparatively widespread Lower Cretaceous chert-pebble grave; and a regional sub-Cretaceous unconformity separating the two units. The two regions differ, however, in the details of distribution and paleoflow directions within these units. In addition, the interpretation of tectonic driving forces differ between the two belts with collisions primarily responsible for the Columbian belt and magmatic activity apparently generating the Sevier belt. By quantitatively analyzing the southern Columbian foreland sequence and comparing these data to our previous study of the Sevier foreland sequence we will determine if the sequences record a similar evolutionary history. If so, then can two different mechanisms active in the Columbian and Sevier belts produce the same stratigraphic record? If not, then how do two very different thrust belt driving mechanisms produce such grossly similar stratigraphic packages and where does the transition lie between the two orogenic belts?