Clastic Dikes as Conduits for Episodic Fluid Flow in the Upper Crust

9304581井眼拟议的研究试图确定和量化碎屑岩脉作为上地壳中断续和快速的流体流动的管道的过程。这项研究将研究加州沿海中新世蒙特雷组硅质页岩中碎屑岩中角砾岩成分的运移机制，以及死亡谷泰特斯峡谷和内华达州谢尔克里克山脉古生代石灰岩中角砾岩组分的运移机制。流体流动的最小速度将利用流动速度、碎屑大小、粘度以及流态和碎屑密度之间的关系来计算。这些参数将根据现场和薄片调查人员、流体包裹体研究和公布的类似岩石类型的密度值进行估计。如果计算出的流过堤坝的流速远远快于大溪流的渗流速度，就可以推断出通过堤防的幕式流体流动。此外，还将探讨碎屑岩中围岩和角砾岩成分破碎的机理。对后一种过程的识别将使人们能够估计孔压下降的幅度和速度。快速滴落被认为是碎屑岩作为大规模幕式流体流动的管道的特征。通过对与碎屑岩脉有关的裂隙封闭脉进行稳定的同位素和微量元素测量，将确定这些岩脉是化学封闭系统还是开放系统。围岩和矿脉充填矿物的锶同位素分析表明，矿脉胶结作用发生在封闭或开放的系统中。拟议的研究将增进目前对上地壳内流体流动机制的了解。这项研究的发现可能会影响应用领域的研究，如地震危险性分析中裂隙岩石中污染物和热量的传输。***

9304581 Boles The proposed study seeks to identify and quantify processes by which clastic dikes serve as conduits for episodic and rapid fluid flow in the upper crust. This study will investigate transport mechanisms for breccia components in clastic dikes in silicious shales of the Miocene Monterey Formation, coastal California, and in Paleozoic limestones both in Titus Canyon, Death Valley, and in the Shell Creek Range, NE Nevada. Minimum velocities of fluid flow will be calculated using relations among flow velocity, clast size, viscosity, and fluid and clast densities in fluidized beds. These parameters will be estimated based on field and thin section investigators, fluid inclusion studies, and published density values of similar rock types. Episodic fluid flow through the dike can be inferred if the calculated flow velocity through the dike is much faster than seepage by darcian flow. In addition, mechanism leading to fragmentation of wall rock and breccia components in clastic dikes will be investigated. Identification of the latter process would allow estimated on the magnitude and rate of drops in pore pressure. Rapid drops are considered as characteristic for clastic dikes serving as conduits for large scale, episodic fluid flow. Stable isotope and trace element measurements across crack seal veins associated with clastic dikes will determine if the dikes were chemically closed or open systems. Strontium isotope analyses of wall rock and vein filling minerals will indicate if vein cementation occurred in a closed or open system. The proposed investigations will increase the present understanding of fluid flow mechanisms within the upper crust. Findings of this study may influence research in applied fields such as transport of contaminants and heat in fractured rocks of earthquake hazard analysis. ***