Origin of Silt in the Permian Phosphoria Formation

粉质海相泥岩是体积学上最重要的沉积岩类型之一，但其成因仍知之甚少。该研究将调查美国西部二叠纪磷化组中的粉砂岩相。研究人员将进行区域沉积学和地层学调查，以评估悬浮沉降与其他沉积过程的重要性，并研究粉砂岩和其他相与海平面变化的关系。不同石英粒度组分的氧同位素分析将用于限制它们的结晶温度，从而限制它们的起源（再加工石英与原生石英）。最后，将在一些分布广泛的地点测量粉砂岩和其他粉砂质相的粒度分布。这些测量结果与高分辨率地层学研究相结合，将用于检查整个磷海的粒度趋势。

ABSTRACTOrigin of Siltstone Facies in the Permian Phosphoria FormationAlan CarrollEAR-0106898Silty marine mudrocks represent one of the most volumetrically important sedimentary rock types, but their genesis remains very poorly understood. The proposed study will investigate siltstone facies contained within the Permian Phosphoria Formation in the western U.S. A regional sedimentologic and stratigraphic investigation will be conducted to assess the importance of suspension settling versus other depositional processes, and to examine the relationship of siltstone and other facies to changing sea level. Oxygen isotopic analyses of different quartz grain size fractions will be used to constrain their temperature of crystallization and thus their origin (reworked versus primary quartz). Finally, grain size distributions from siltstone and other silty facies will be measured at a number of widely distributed sites. These measurements, combined with high-resolution stratigraphic studies, will be used to examine grainsize trends across the Phosphoria sea.