Metamorphic Evolution of Mid-To-Deep Levels of the Continental Crust in Northern Idaho

爱达荷州北部大陆地壳中深层的变质演化

• 批准号: 8904541
• 负责人: Jack Rice
• 金额: $ 10万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-12-15 至 1992-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8904541&HistoricalAwards=false
• 关键词: Metamorphic; Evolution; Mid; Deep; Levels

This proposal requests continued support for a research program devoted to understanding the thermal and tectonic history of the North American Cordillera as exposed in northern Idaho. Previous studies by the P.I. and graduate students at the University of Oregon, have demonstrated that three major metamorphic events are recorded in pelitic and calcareous rocks north of the Idaho Batholith. Structural, mineralogical and chemical evidence for these events provide important data hearing on the evolution of the continental crust. The propose research will be directed toward improving our understanding of the metamorphic history, and the relationships between metamorphism, deformation and plutonism. Geothermometry and geobarometry will be carried out using a new approach which solves all equilibria implied by a mineral paragenesis simultaneously. Zoned minerals, especially garnet, will be studied in order to estimate the P-T time path of prograde metamorphism, and the decompression path associated with uplift. Such calculations will be tested with a new method of calculating equilibrium mineral assemblages and compositions with a free energy minimization algorithm. Fluid- rock interactions will also be examined by careful studies of interlayered calcareous and pelitic compositions. The phase equilibrium relations in calcareous rocks, which equilibrated with very saline fluids, will be examined in the light of new data bearing on the thermodynamic properties of minerals and aqueous species in the system H2O-CO2-NaCl. A new model describing the compositional relations among the mineral scapolite and NaCl-rich fluid will be developed and applied to the natural occurrences. Stable isotopic analyses will be undertaken in order to more fully characterize the nature, source and amounts of fluid reacting with a variety of rock compositions. Isotopic age determinations will be made in an attempt to learn the timing of multiple metamorphism, and the relationship of metamorphism of intrusion of the Idaho Batholith.

该提案要求继续支持一项研究， 致力于了解热历史和构造历史的项目 产于北美科迪勒拉山脉，暴露于北方爱达荷州。 P.I.之前的研究和研究生， 俄勒冈州大学的研究表明， 变质事件记录在泥质和钙质岩石中 在爱达荷州的北卡罗来纳州 结构、矿物和 这些事件的化学证据提供了重要的数据听证会 大陆地壳的演化 建议研究 将致力于提高我们对 变质作用的历史，以及变质作用， 变形作用和深成作用。 地质测温和地质测压将 使用一种新的方法来解决所有的平衡， 同时存在矿物共生现象。 分区矿物， 特别是石榴石，将被研究，以估计P-T 进变质作用的时间路径和减压路径 与隆起有关。 这种计算将用一个 平衡矿物组合计算的新方法 用自由能最小化算法计算组合物。 液体- 岩石的相互作用也将通过仔细研究 层间钙质和泥质成分。 相位 石灰岩中的平衡关系， 与非常咸的液体，将在新的光检查 有关矿物热力学性质的数据， H_2 O-CO_2-NaCl体系中的水相物种。 新模式 描述矿物之间的成分关系 方柱石和富NaCl流体将被开发和应用于 自然事件。 稳定同位素分析将在 为了更充分地描述其性质、来源和性质， 大量的流体与各种岩石发生反应 组合物的 同位素年龄测定将在一个 试图了解多重变质作用的时间， 与爱达荷州侵入岩变质作用的关系。