The redox-sensitive geochemical behavior of uranium permits the use of Th/U ratios as a geochemical proxy for the oxidation state of the atmosphere and oceans during sedimentary processes. Due to the effects of post-depositional uranium mobility on Th/U ratios during events involving oxygenated fluids, direct measurements of Th/U ratios are often misleading, but the whole rock Pb isotope compos...

The study area is situated in the Middle part of the Tabas Block. It contains outcrops of rocks that formed along longitudinal faults in Early Cimmerian orogenic phase. The basin subsided along these faults from the Late Triassic to Early Cretaceous, which include two sedimentary cycles. A sedimentary cycle, related to Upper Triassic to Bajocian is known as Shemshak group. Another sedimentary c...

—Many features of global diversity compilations have proven robust to continued sampling and taxonomic revision. Inherent biases in the stratigraphic record may nevertheless substantially affect estimates of global taxonomic diversity. Here we focus on short-term (epoch-level) changes in apparent diversity. We use a simple estimate of the amount of marine sedimentary rock available for sampling...

the etive igneous complex has intruded into dalradian and moine meta-sedimentary rocks in devonian. main rock types of the complex are granodiorite, monzodiorite, monzogranite, granite and diorite. geochemical studies show that the magmas were of high k calc-alkaline, i-type and metaluminous nature. application of discriminant diagrams to the etive rocks indicates a possible within-plate tecton...

rock-eval pyrolysis and oxidation are the most widely used methods by exploration companies for identifying and evaluating potential source rocks in sedimentary basins. in this article, these methods and the parameters resulted from their application are first  explained.  then,  based on screened data resulted from analyzing 499 outcrop samples by using rock-eval pyrolysis and oxidation method...

The Medusae Fossae Formation (MFF) is an enigmatic sedimentary unit near the equator of Mars, with uncertain formation process and absolute age. Due to heavily wind-eroded surface, it difficult determine model age MFF using a one-parameter based on crater size-frequency distribution function existing count data. We create new two-parameter that estimates both constant erosion rate ($\beta$) by ...