Thermal Anomalies and Fluid Flow in the Continental Crust

大陆地壳中的热异常和流体流动

• 批准号: 9219886
• 负责人: David Deming
• 金额: $ 9.55万
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-03-01 至 1996-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9219886&HistoricalAwards=false
• 关键词: Thermal; Anomalies; Fluid; Flow; Continental

Fluids are involved in nearly all geologic processes, and are ubiquitous in the continental crust to depths of at least 10 to 15 km. As heat is advected by fluid movement, it may lead to distinctive patterns of thermal anomalies which can be interpreted to gain insight into fluid pathways and mechanisms. Field studies of past and present temperatures in the Ouachita Mountains- Arkoma basin area re proposed to gain insight into the mechanisms by which fluid flow occurs in the continental crust and the nature of possible relationships between fluid migrations and orogenesis. The Arkoma basin and Ouachita mountains are of interest because they have been implicated as a source of the hot brines which apparently flooded North America in Late Pennsylvanian-Early Permian time (about 300 +25 Ma), leading to widespread potassic alteration, formation of Mississippi Valley-type (MVT) lead-zinc deposits, and possible resetting of paleomagnetic poles. Mathematical models will also be used to evaluate various hypotheses concerning the mechanisms by which fluid flow takes place in the continental crust. Modeling will include a study of (1) temporal focusing of compaction- or metamorphic-derived fluids, (2) catastrophic release of heat in the crust from free convection an the interaction of free- and forced- convective flow regimes, and (3) the conditions under which free convection is important in tilted geologic media such as may occur in sedimentary basins. Results of the mathematical modeling will be used in conjunction with data collected in field studies to evaluate hypotheses concerning fluid flow in the continental crust, particularly in reference to tectonically-driven fluid migrations.

流体几乎参与所有地质过程，并且在至少 10 至 15 公里深度的大陆地壳中无处不在。 由于热量是通过流体运动进行平流传播的，因此可能会导致独特的热异常模式，可以对其进行解释以深入了解流体路径和机制。 建议对沃希托山脉-阿科马盆地地区过去和现在的温度进行实地研究，以深入了解大陆地壳中流体流动的机制以及流体迁移和造山作用之间可能关系的性质。 阿科马盆地和沃希托山脉之所以引起人们的关注，是因为它们被认为是热盐水的来源，这些热盐水显然在宾夕法尼亚晚期至二叠纪早期（约 300+25Ma）期间淹没了北美，导致了广泛的钾质蚀变，形成了密西西比河谷型（MVT）铅锌矿床，并可能重置了古地磁极。 数学模型还将用于评估有关大陆地壳中流体流动机制的各种假设。 建模将包括以下方面的研究：（1）压实或变质衍生流体的时间聚焦，（2）自由对流导致地壳中热量的灾难性释放以及自由对流和强制对流流态的相互作用，以及（3）自由对流在倾斜地质介质（例如沉积盆地中可能发生的）中发挥重要作用的条件。 数学模型的结果将与现场研究中收集的数据结合使用，以评估有关大陆地壳流体流动的假设，特别是关于构造驱动的流体迁移。