Chemical, Mineralogical and Fabric Evolution of the Lower Stanley Shale, Ouachita Mountains

沃希托山脉下斯坦利页岩的化学、矿物学和结构演化

• 批准号: 9017294
• 负责人: Lynton Land
• 金额: $ 11.52万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-01-15 至 1993-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9017294&HistoricalAwards=false
• 关键词: Chemical; Mineralogical; Fabric; Evolution; Lower

The Mississippian Stanley Shale exposed in the Ouachita Mountains of Arkansas and Oklahoma exhibits surprising bulk chemical characteristics that are probably related either to metamorphic processes or to hydrothermal alteration. The west to east increase in metamorphic grade seen in the Ouachitas is paralleled by bulk chemical changes including depletion in Mg, Ca, Na, K, and Ba, and relative enrichment in Al and Li. The increased Al content is reflected in an increased abundance of aluminous phases such as chloritoid and pyrophyllite. The changes in bulk chemistry suggest that the Stanley may have exported material to surrounding terrains. It is necessary to evaluate the processes that may have led to the chemical and mineralogical changes recorded in the Ouachitas. To do so involves a study of the differences in bulk chemistry, mineralogy, and fabric that exist between diagenetic Stanley in the western Ouachitas and greenschist facies Stanley in the eastern Ouachitas. In particular, this research will document changes in fabric, bulk chemistry and isotopic tracers that may be useful in estimating volume loss and evaluating the extent to which the Stanley was an open system during diagenesis/metamorphism.

暴露于阿肯色州和俄克拉荷马州沃希托山脉的密西西比斯坦利页岩表现出令人惊讶的大量化学特征，这些特征可能与变质过程或热液蚀变有关。 瓦希塔斯地区变质程度从西向东增加，同时伴随着大量化学变化，包括镁、钙、钠、钾和钡的消耗，以及铝和锂的相对富集。 铝含量的增加反映在铝相（例如绿泥石和叶腊石）丰度的增加。 大量化学成分的变化表明斯坦利号可能已向周围地区输出了物质。 有必要评估可能导致沃希托斯记录的化学和矿物学变化的过程。 为此，需要研究沃希托州西部的成岩斯坦利和沃希托州东部的绿片岩相斯坦利之间存在的整体化学、矿物学和结构差异。 特别是，这项研究将记录织物、本体化学和同位素示踪剂的变化，这些变化可能有助于估计体积损失和评估斯坦利在成岩/变质作用期间作为开放系统的程度。