Relative Roles of Late Cretaceous-Early Tertiary Versus Middle Tertiary Extension in Southeastern California and Southwestern Arizona

加利福尼亚州东南部和亚利桑那州西南部晚白垩世-早第三纪与中第三纪伸展的相对作用

• 批准号: 9526589
• 负责人: Carl Jacobson
• 金额: $ 14.08万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-03-15 至 2000-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9526589&HistoricalAwards=false
• 关键词: Relative; Roles; Late; Cretaceous; Early

9626589 Jacobson The Palona, Orocopia and Rand Schists are Late Cretaceous-early Tertiary subduction zone rocks in southern California and southwestern most Arizona. These rocks were emplaced beneath the mesozoic arc of western North America along the vicent-chocolate mountain thrust, according to one model, originating during low-angle, east-dipping subduction. Thus the model implies top to the west sense of movement. However, many studies have documented top to the east movement on many exposures of the fault, which due to subduction, would reverse subduction polarity and create several geometric problems for Loramide tectonics. Recent work has indicated that many of these "wrong way" kinetic indicators may be due to later, normal faulting reactivation of the thrust surface. This project will focus on this possible reactivation and will attempt to date the movement. Successful results will help finally resolve one of the main controversies of the Cretaceous tectonic geometry of the southwest margin of North America, and illuminate the younger extensional event.

小行星9626589 帕洛纳、奥罗科皮亚和兰德片岩是加州南部和亚利桑那州西南部的晚白垩世-早第三纪俯冲带岩石。 根据一种模型，这些岩石是在低角度东倾俯冲过程中形成的，沿着沿着的巧克力山逆冲断层，侵位在北美西部中生代岛弧之下。 因此，该模型暗示了自上而下的运动感。 然而，许多研究已经记录了断层的许多暴露的自上而下向东的运动，由于俯冲，这将逆转俯冲极性，并为Loramide构造带来几个几何问题。 最近的工作表明，许多这些“错误的方式”的动力学指标可能是由于后来，正常断层的逆冲面的再活化。 本项目将侧重于这种可能的重新激活，并将试图确定运动的日期。 成功的结果将有助于最终解决北美西南缘白垩纪构造几何学的主要争议之一，并阐明更年轻的伸展事件。