primary sedimentary and secondary structural and diagenetic processes are responsible for heterogeneity in carbonate reservoirs and recognition of these factors is very essential subject in modeling these reservoirs. image logs are very useful for identification of structures and small scale sedimentary features. in this research, using image analysis of formation microimager log (fmi) in a dri...

An integrated stratigraphic analysis of the Coimbra Formation was performed in S. Pedro de Moel outcrops Lusitanian Basin (Portugal). This unit is dated from lower–upper (Oxynotum Chronozone) Sinemurian and subdivided into eight informal subunits. Except for its base, consisting dolostones microbialites, much succession consists bioclastic bioturbated micritic centimetric–decimetric limestones ...

Deep-sea pore fluids are potential archives of ancient seawater chemistry. However, the primary signal recorded in pore fluids is often overprinted by diagenetic processes. Recent studies have suggested that depth profiles of Mg concentration in deep-sea carbonate pore fluids are best explained by a rapid rise in seawater Mg over the last 10–20 Myr. To explore this possibility we measured the M...

Assemblages of clay minerals are routinely used as proxies for paleoclimatic change and paleoenvironmental conditions in Phanerozoic rocks. However, this tool is rarely applied in older sedimentary units. In this paper, the clay mineralogy of the Doushantuo Formation in South China is documented, providing constraints on depositional conditions of the Ediacaran Yangtze platform that host the ea...

Patagonia exhibits a particularly abundant record of Cretaceous dinosaurs with worldwide relevance. Although paleontological studies are relatively numerous, few include taphonomic information about these faunas. This contribution provides the first detailed sedimentological and taphonomical analyses of a dinosaur bone quarry from northern Neuquén Basin. At Arroyo Seco (Mendoza Province, Argent...

Limestone–marl alternations are commonly used for high-resolution cyclostratigraphic studies and palaeoenvironmental reconstructions, but diagenetic indicate that not all limestone–marl reflect genuine differences in the initial sediment composition driven by environmental changes. Differences ratios of diagenetically inert trace elements between limestones marls changes affecting terrigenous f...

The mechanisms of early diagenetic quartz formation under low-temperature conditions are still poorly understood. In this study we investigated lithified cherts consisting of microcrystalline quartz recovered near the base of a 420 m thick Miocene-Holocene sequence of nannofossil and diatom ooze at a drill site in the Eastern Equatorial Pacific (Ocean Drilling Program Site 1226). Precipitation ...

Natural fractures act as critical flow channels and reservoir space in the Lucaogou Formation tight of Jimsar Sag. It is essential to identify main controlling factors natural order achieve efficient development oil this area. There are mainly three types fractures, including tectonic diagenetic abnormal overpressure-induced fractures. Diagenetic predominantly bedding seams. The fracture affect...