Stratigraphic and Tectonic Analysis of Neogene Coal-Bearing Basins Along the Alaska Range Suture Zone

该提案寻求对位于阿拉斯加山脉中北部的新近纪沉积盆地进行为期三年的调查。这些盆地包含了沿古缝合带的盆地发育记录、北美最高山脉的隆升历史、广泛的低硫煤储量和潜在的石油储层。东西向盆地为河流和湖相沉积，由中新世Usibelli群（~ 600 m厚）和上新世Nenana砾石（~ 1000 m厚）组成。要解决的一般问题包括：(1)盆地是如何在碰撞/增生造山带内部形成的？是否可以建立一个沿原缝合带形成盆地的概念模型？(2)这些盆地中所含的同造陆沉积能告诉我们关于阿拉斯加山脉新近纪隆升的什么信息？碎屑记录是否包含关于该造山带沿走向和随时间变化的变形和隆升的信息？在阿拉斯加山脉拆顶过程中，古气候对碎屑成分的影响是什么？(3) Usibelli集团的煤炭正在成为阿拉斯加和向环太平洋国家出口的越来越重要的能源来源。沉积、构造和气候对这些盆地的煤沉积有什么控制作用？为了回答这些问题，需要对所有新近纪盆地进行区域综合的地层、古地理和构造格架。将通过重建每个盆地的沉积系统建立一个数据库；穿过阿拉斯加山脉中部的一系列横断面的建设；砂岩和砾岩的成分分析。本研究的主要贡献包括：记录了沿缝合带沉积盆地的长期演化；描绘阿拉斯加山脉隆升史中沿走向的变化；并分析了未来勘探潜在商业煤的分布。

9725587 Ridgway This proposal seeks funding for a three-year investigation of Neogene sedimentary basins located along the north-central flank of the Alaska Range. These basins contain the record of basin development along an ancient suture zone, the uplift history of the highest mountain range in North America, extensive low-sulfur coal reserves, and potential petroleum reservoirs. The east-west trending basins were filled by fluvial and lacustrine deposits and consist of the Miocene Usibelli Group (~ 600 m thick) and the Pliocene Nenana Gravel (~ 1000 m thick). The general questions to be addressed include: (1) How do basins form within the interior of collisional/accretionary orogenic settings? Can a conceptual model be developed for basin formation along former suture zones? (2) What can the synorogenic deposits contained within these basins teach us about the Neogene uplift of the Alaska Range? Does the detrital record contain information on how deformation and uplift changed along strike and through time for this orogenic belt? What was the influence of paleoclimate on detrital composition during unroofing of the Alaska Range? (3) Coal from the Usibelli Group is becoming an increasingly important energy source for Alaska and for export to Pacific Rim countries. What were the depositional, tectonic, and climatic controls on coal deposition in these basins? A regionally integrated stratigraphic, paleogeographic and tectonic framework for all the Neogene basins will be needed to answer these questions. A database will be established by reconstructing the depositional systems for each basin; construction of a series of cross sections through the central Alaska Range; and compositional analysis of sandstone's and conglomerates. Major contributions of the proposed research include documentation of the long term evolution of sedimentary basins along a suture zone; delineation of along strike variations in the uplift history of the Alaska Range; and analysis of the distribution of potentially commercial coals for future exploration.