Diagenesis of Sandstones in Foreland and Piggy-back Basins, Northern Apennines

意大利亚平宁北部这两类盆地的出露情况非常好，非常接近，是背靠式盆地的典型地区。岩石类型和几何形状；水泥和孔隙在层面、断层和页岩中的分布；砂岩/页岩比率；以及埋藏和构造史是将进行比较的主要特征。将利用偏光、扫描电子显微镜、阴极发光、电子探针显微分析、流体包裹体、稳定同位素地球化学、重矿物成分、镜质组反射率、磷灰石裂变径迹数据以及露头关系来研究成岩特征。该项目的目的是比较和对比两种不同类型的沉积盆地(背靠型和前陆)中与年龄相当的砂岩的胶结作用和其他成岩作用，以分离原因和影响，并确定控制成岩作用的许多变量的相对重要性。了解沉积盆地中砂岩的成岩作用，对于评价砂岩的碳氢化合物和水的储集层质量以及评价用于有毒废物处置的砂岩中的岩石-水相互作用的作用具有重要的应用价值。了解砂岩中的成岩作用对于解释砂岩的后沉积历史、化学成分的源汇和解释砂岩的物源也是至关重要的。这是一项合作研究，涉及四名意大利沉积地质学家(摩德纳大学和博洛尼亚大学)和四名来自德克萨斯大学奥斯汀分校的沉积地质学家。在亚平宁北部进行这项研究的原因是：1)在一个很小的地理区域(200×150公里)，有两种不同类型的盆地中沉积的同时代岩石的极好暴露；2)知道岩石的地层和沉积学以及构造历史；3)有机会在一个意大利团队得到支持的项目上进行国际合作。

The northern Apennines, Italy, have excellent exposures of these two types of basins in close proximity and is the type area of piggy-back basins. Rock type and geometry; distribution of cements and pores with respect to bedding planes, faults, and shales; sandstone/shale ratio; and burial and tectonic history are major features that will be compared. Diagenetic features will be studied using polarized light, scanning electron microscopy, cathodoluminescence, electron probe microanalysis, fluid inclusions, stable isotope geochemistry, heavy mineral composition, vitrinite reflectance, apatite fission-track data in addition to outcrop relations. The purpose of this project is to compare and contrast cementation and other diagenetic aspects of age-equivalent sandstones from two different types of sedimentary basins, piggy- back and foreland, in order to isolate causes and effects and to identify the relative importance of the many variables controlling diagenesis. Understanding sandstone diagenesis in sedimentary basins has an important applied use in assessing hydrocarbon and water reservoir quality of sandstones and in assessing the role of rock-water interactions in sandstones used for toxic waste disposal. Understanding diagenesis in sandstones also is essential to interpreting the post-depositional history of sandstones, the sources and sinks of chemical components, and interpreting the provenance of sandstones. This is a cooperative study involving four Italian sedimentary geologists (Universities of Modena and Bologna) and four sedimentary geologists from the University of Texas at Austin. The reasons for doing the study in the northern Apennines are: 1) there are excellent exposures of coeval rocks deposited in two different types of basins in a small geographic area (200 x 150 km), 2) the stratigraphy and sedimentology of the rocks and structural history are known, and 3) opportunity for international cooperation on a project for which the Italian team has obtained support.