Alleghenian Episode of Basin-Wide Illitization in the Appalachians - A Test of Fluid Expulsion Hypothesis

阿巴拉契亚山脉阿勒格尼时期全流域伊利特化——流体排出假说的检验

• 批准号: 8709329
• 负责人: James Aronson
• 金额: $ 12.85万
• 依托单位: Case Western Reserve University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-15 至 1990-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8709329&HistoricalAwards=false
• 关键词: Alleghenian; Episode; Basin; Wide; Illitization

The illitization of smectite during diagenesis and burial metamorphism is a major aspect of shale petrology; K/Ar dating has elucidated the process. Bentonites simplify the study because they are free of detrital illite/smectite. Recent research shows that Ordovician bentonites throughout the southern half of the Applachian basin underwent illitization to potassium (K)- bentonites during a relatively short episode 300-265 m.y. ago in the upper Pennslyvania- lower Permian, corresponding to the Alleghenian Orogeny. Some of the K-bentonites are in close association with Mississippi Valley Type (MVT) zinc deposits. Basin-wide illitization may be attributed to explusion of edge of the foreland basin during Blue Ridge overthrusting, a novel hypothesis that is receiving support from diverse observations by many researchers. If true, the explusion of hot waters to the distal edges of the basin as of mega-importance to the secondary history of such sedimentary basins, as outlined in the speculative hypothesis by Oliver (1986). This project will contrast the geographic distribution of illitization dates (1) within the Appalachian Basin from south to north, where the timing and character of the Alleghenian Orogeny may have been different; (2) between the Appalachian Basin and Illinois Basin along their divide at the Cincinnati Arch-Nashville Dome; and (3) between the Appalachian and Ouachita/Arkoma Basins along the strike of the orogen. Finally the petrology of the smectite to illite reaction in Appalachian shales should provide a marked contrast with the generally accepted model proposed from deeply buried cases like the Gulf Coast, where the chemical breakdown of detrital K-feldspar plays a major role.

蒙皂石在成岩和埋藏过程中的伊利石化作用 变质作用是页岩岩石学的一个主要方面; K/Ar定年 阐明了这个过程 膨润土简化了研究 因为它们不含碎屑伊利石/蒙脱石。 最近 研究表明，奥陶纪的钙钛矿 阿普拉契盆地的南半部经历了伊利石化， 相对较短时期内的钾（K）-膨润土 3亿至2.65亿年早在上宾夕法尼亚-下二叠纪， 与阿勒格尼造山运动相对应 一些 钾镁矾与密西西比河谷关系密切 MVT型锌矿床。 全盆地伊利石化可能归因于 在蓝岭逆冲推覆过程中， 一个新的假设，得到了不同的支持， 许多研究人员的观察。 如果这是真的， 沃茨到盆地的远端边缘， 这种沉积盆地的次级历史，如概述的 在奥利弗（1986）的推测假说中。 这个项目 将对比伊利化的地理分布 日期（1）在阿巴拉契亚盆地从南到北， 阿勒格尼造山运动的时间和特征 （2）在阿巴拉契亚盆地和 伊利诺斯盆地沿着他们在辛辛那提的分水岭 Arch-Nashville Dome;（3）在阿巴拉契亚山脉和 沿着造山带走向的瓦希塔/阿尔科马盆地。 最后 阿巴拉契亚蒙皂石-伊利石反应的岩石学 页岩应该与通常的 一个公认的模式，提出了深埋的情况下，如海湾 海岸，在那里碎屑钾长石的化学分解 扮演着重要的角色