Collaborative Research: Clinker Geochronology and Geomorphic Evolution of the Powder River Basin, Wyoming

合作研究：怀俄明州粉河盆地的熟料地质年代学和地貌演化

• 批准号: 0649425
• 负责人: Peter Reiners
• 金额: $ 11.6万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-10-01 至 2008-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0649425&HistoricalAwards=false
• 关键词: Collaborative; Research; Clinker; Geochronology; Geomorphic

Clinker, rock metamorphosed by natural coal burning, has formed in the Powder River Basin (and other areas of the Rocky Mountains) since at least Pliocene. Clinker dominates the topographic form of many of the basins in which it is found, because it is more resistant to weathering than surrounding unaltered bedrock. It also preserves a record of the spatial-temporal patterns of fluvial incision, lateral backwasting, and plateau formation in these landscapes, because coal only burns when close to the surface, above the water table and ventilated with surface oxygen. Using (U-Th)/He ages of detrital zircons that are reset during clinker formation, we will map the patterns of coal burning and shallow exhumation in detail in several regions of the PRB in Wyoming and Montana, as well as characterize clinker ages over a broader scale throughout the basin. Model predictions of clinker age-patterns in individual drainages and across the landscape suggest that our results will be able to discriminate between at least some of these possible climatological or tectonic mechanisms driving landscape evolution. This work will form the basis of collaborative research between Reiners and Riihimaki, as well as individuals in the BLM and the Northern Cheyenne Tribe, and undergraduate students from Yale and Bryn Mawr.

熟料是由自然煤炭燃烧而变质的岩石，至少自上新世以来就在保德河盆地（以及落基山脉的其他地区）形成。熟料在许多发现它的盆地的地形形态中占主导地位，因为它比周围未改变的基岩更能抵抗风化。它还保留了这些景观中河流切割、横向回灌和高原形成的时空模式的记录，因为煤炭只有在靠近地表、高于地下水位并有地表氧气通风时才会燃烧。利用熟料形成过程中重置的碎屑锆石 (U-Th)/He 年龄，我们将详细绘制怀俄明州和蒙大拿州 PRB 几个地区的煤炭燃烧和浅层折返模式，并描述熟料年龄整个盆地范围更广。对各个排水系统和整个景观中熟料年龄模式的模型预测表明，我们的结果将能够区分至少一些驱动景观演化的可能的气候或构造机制。这项工作将构成 Reiners 和 Riihimaki、BLM 和北夏延部落的个人以及耶鲁大学和布林莫尔大学的本科生之间合作研究的基础。