Collaborative Research: Regional Chronostratigraphic and Sequence Stratigraphic Analysis of Central Cordilleran Foreland Basin

该项目包括一个详细的， 年代地层学、沉积学和层序地层学 上侏罗统-下侏罗统非海相岩石分析 白垩纪莫里森组、克洛弗利组和库特奈组以及 相当于甘尼特群的地层。 为了整合 层序地层学分析与海洋记录 前陆盆地，研究将包括边界海相岩石在 圣丹斯组（侏罗纪）和瑟莫波利斯组（白垩纪）。 地区 数据收集包括粉河流域和布莱克丘陵， 莎士比亚-怀俄明冲断带和大福尔斯周围地区 在蒙大拿州中西部 详细的相分析，岩相薄片的点计数 剖面和砾岩碎屑计数，河流露头绘图 通道复合物，次表面到表面的相关性， 地球物理测井、详细的磁性地层学和裂变- 富灰层自形锆石径迹年龄测定 将被执行。 这个数据库的主要结果将是一个完整的 莫里森-克洛弗里年代和岩石地层格架 在怀俄明州的西部和北部的层序及其等同物。 的 数据库将覆盖25万公里的区域， 盆地的近端部分到其东部终点附近。 之间 其他重要成果将是（1）层序地层学 非海相岩石在欠充填和过充填时的骨架 部分前陆盆地;（2）新的年代地层 科迪勒拉前陆早期充填控制模型 盆地;（3）新的和更完整的理解的外在 （构造、海平面、气候）对早期科迪勒拉山脉的控制 前陆盆地 结果也将提供一个最大的 与现有和正在开发的地球物理数据库进行比较的数据库 前陆盆地模式

The project consists of a detailed, regional chronostratigraphic, sedimentologic, and sequence stratigraphic analysis of nonmarine rocks in the Upper Jurassic - Lower Cretaceous Morrison, Cloverly, and Kootenai Formations and the equivalent strata of the Gannett Group. In order to integrate sequence stratigraphic analysis with the marine record of the foreland basin, the study will include bounding marine rocks in the Sundance (Jurassic) and Thermopolis (Cretaceous) Formations. Areas of data collection include the Powder River basin and Black HIlls, the Idaho-Wyoming thrust belt, and the area surrounding Great Falls in west-central Montana. Detailed facies analysis, point counts of petrographic thin sections and conglomerate clast counts, outcrop mapping of fluvial channel complexes, subsurface-to-surface correlations of geophysical well logs, detailed magnetostratigraphy, and fission- track dating of euhedral zircons from selected ash-rich horizons will be performed. The principal results of this data base will be a complete chrono - and lithostratigraphic framework for the Morrison-Cloverly sequence and its equivalents to the west and north of Wyoming. The Data base will span an area covering - 250,000 km , from the proximal part of the basin to near its eastern terminus. Among other important results will be (1) a sequence - stratigraphic framework for nonmarine rocks in both underfilled and overfilled parts of foreland basins; (2) a new chronostratigraphically controlled model for early filling of the Cordilleran foreland basin; and (3) new and more complete understanding of the extrinsic (tectonic, eustatic, climatic) controls on the early Cordilleran foreland basin. The results also will provide one of the largest data bases for comparison with available and developing geophysical models for foreland basins.