Proterozoic Thermal Evolution of the Southwestern U.S.

美国西南部元古代热演化

• 批准号: 9405696
• 负责人: Samuel Bowring
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-01 至 1998-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9405696&HistoricalAwards=false
• 关键词: Proterozoic; Thermal; Evolution; Southwestern; U.S.

9405696 Bowring Prior research in the Proterozoic of Arizona and New Mexico has resulted in a hypothesis that, after initial accretion, the proterozoic orogenic belt remained stable from 1.7 Ga to 1.4 Ga, with isotherms moving through the rock very slowly, allowing extensive diffusional loss of argon from various minerals, preserved as extreme gradations from cones to rims. An alternative hypothesis of partial resetting by heat from younger intrusions does not fit well with the geologic history, pattern of metamorphism, petrologic aspects of re-metamorphism or known volume of plutons, but remaining an attractive alternative. The project will attempt to test these alternatives in a field and geochronological program. The project offers a strong opportunity to study thermal evolution of newly formed continental lithosphere and to unravel how stable cratonic geotherms are attained.

9405696鲍林先前对亚利桑那州和新墨西哥州的元古代的研究已经产生了一种假设，即在最初的增生之后，元古代造山带在1.7 Ga到1.4 Ga之间保持稳定，等温线在岩石中移动非常缓慢，允许各种矿物中的氩广泛扩散损失，从锥体到边缘的极端渐变保存下来。 另一种假说的部分重置的热量从年轻的侵入体不符合地质历史，变质作用的模式，岩石学方面的再变质作用或已知量的岩体，但仍然是一个有吸引力的替代。 该项目将试图在野外和地质年代学项目中测试这些替代方案。 该项目提供了一个很好的机会，研究新形成的大陆岩石圈的热演化，并解开如何获得稳定的地幔地热。