Detrital Zircon Geochronology of Colorado Plateau Mesozoic Strata: Implications for Continental Paleogeography and Paleotectonics

科罗拉多高原中生代地层碎屑锆石年代学：对大陆古地理和古构造学的启示

• 批准号: 0341987
• 负责人: William Dickinson
• 金额: --
• 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: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0341987&HistoricalAwards=false
• 关键词: Detrital; Zircon; Geochronology; Colorado; Plateau

Detrital Zircon Geochronology of Colorado Plateau Mesozoic Strata: Implications for Continental Paleogeography and PaleotectonicsW.R. Dickinson, G.E. Gehrels, P.G. Decelles (University of Arizona)EAR-0341987ABSTRACTThe ability to obtain radiometric ages for individual sand grains of the mineral zircon by determining isotopic ratios of uranium and lead contained within the zircon now makes it possible to establish the ages of the eroded bedrock sources that contributed sand grains to sedimentary strata. By applying this technique systematically for the first time to strata of the Colorado Plateau, which exposes the most complete Mesozoic succession in North America, we expect to advance our understanding of the Mesozoic paleogeography of the continent to a level not previously attainable. By coupling knowledge of the ages of potential bedrock sources in different parts of North America with the new information on the ages of zircon grains in strata of the Colorado Plateau, we can infer the patterns of Mesozoic paleorivers that transported sand across the ancient continental surface, and of paleowind systems responsible for deposition of vast paleodune fields that are among the largest in the global geologic record. Knowing the directions of transcontinental sediment transport through Mesozoic time will shed light in turn on evolution of the Appalachian (eastern) and Cordilleran (western) mountain chains of the continental margins because paleodrainages head in highlands, and change configuration as highlands are uplifted by tectonic activity or subdued by erosion. The design of the project involves participation by undergraduate students in all phases of the research as junior colleagues of the faculty investigators.

科罗拉多高原中生代地层碎屑锆石年代学：对大陆古地理和古构造的启示[j]。Dickinson， G.E. Gehrels， P.G. Decelles（亚利桑那大学）：通过测定锆石中所含铀和铅的同位素比例，可以获得锆石中单个砂粒的放射性年龄，这使得确定沉积地层中砂粒形成的侵蚀基岩源的年龄成为可能。通过首次系统地将这种技术应用于科罗拉多高原的地层，我们期望将我们对大陆中生代古地理的理解提高到以前无法达到的水平。科罗拉多高原揭示了北美最完整的中生代演替。通过将北美不同地区潜在基岩源年龄的知识与科罗拉多高原地层中锆石颗粒年龄的新信息相结合，我们可以推断出在古代大陆表面运输沙子的中生代古河流的模式，以及在全球地质记录中最大的古山田沉积中负责古风系统的模式。了解中生代跨大陆沉积物运输的方向，将有助于揭示大陆边缘阿巴拉契亚山脉（东部）和科迪勒兰山脉（西部）的演化，因为古水系始发于高地，并随着高地因构造活动而隆起或因侵蚀而减弱而改变形态。该项目的设计涉及到本科生作为学院研究人员的初级同事参与研究的各个阶段。