Testing the Utility of Detrital Zircon Provenance Analyses: Neogene Drainage Capture and the Snake River Plain-Yellowstone Hot Spot

测试碎屑锆石来源分析的实用性：新近系排水捕获和蛇河平原-黄石热区EAR-0125756爱达荷州州立大学保罗·卡尔·林克EAR-0125756该提案将利用蛇河平原-黄石热点系统周围河流系统中碎屑锆石颗粒的分布，建立使用碎屑锆石作为河流系统来源指纹的置信度。在落基山脉北部，黄石-蛇河平原热区及其伴生的地形隆起从中新世晚期(17 Ma)开始向东北方向迁移至今。在此期间，北美西部大陆分水岭一直伴随着迁徙的地形隆起的顶峰。因此，在中新世中期位于爱达荷州中部大陆分水岭以东的区域排水，被从地形凸起向北和向南径向流动的溪流破坏。随着热点的通过和蛇河平原的下沉，向西流动的蛇河逐渐吞噬了几条河流的片段，导致它们向西流动，而不是向北、向南或向东。迁移热点模型对中新世至近期的水系捕获做出了可检验的预测。该项目将测试碎屑锆石源区方法在准确记录流域物源方面的应用。PI将使用SHRIMP(灵敏高分辨率离子微探针)U-Pb年代学分析，每个颗粒来自落基山脉北部现代河流和新近纪陆相沉积物的约50个样本。他将研究河流系统的大小阈值，在那里混合开始掩盖独特的锆石特征。

Testing the Utility of Detrital Zircon Provenance Analyses: Neogene Drainage Capture and the Snake River Plain-Yellowstone Hot SpotPaul Karl Link, Idaho State UniversityEAR-0125756This proposal will use the distribution of detrital zircon grains in stream systems surrounding the Snake River Plain-Yellowstone hotspot system to establish confidence limits on the use of detrital zircons as a fingerprint of provenance in fluvial systems. In the northern Rocky Mountains the Yellowstone-Snake River Plain hotspot and its associated topographic bulge have migrated northeastward from the late Miocene (17 Ma) to the present. During this time, the western continental divide of North America has followed the crest of the migrating topographic bulge. Thus, regional drainage, which in middle Miocene time was to the east from a continental divide in central Idaho, was disrupted to radial north- and south-flowing streams draining away from the topographic bulge. Following passage of the hot spot and subsidence of the Snake River Plain in its wake, the west-flowing Snake River has progressively captured segments of several streams, causing them to flow west, rather than north, south, or east. The migrating hotspot model makes testable predictions about Miocene to Recent drainage capture. This project will test the utility of the detrital zircon provenance method to accurately record drainage basin provenance. PI will use SHRIMP (Sensitive High-Resolution Ion Microprobe) U-Pb geochronologic analyses of 60 grains each, from about 50 samples from modern streams and Neogene terrestrial sediments from the northern Rocky Mountains. He will investigate the size threshold of fluvial systems where mixing begins to mask distinctive zircon signatures.