the olang area is a part of gheshlagh-olang synclinal, which is a member of eastern alborz coal basin and is situated at a distance of70 km northeast of shahroud city. coal-bearing strata of this region are part of the shemshak group (upper triassic to lower jurassic).samples from the 9 coal seams of the olang coal deposits were collected and ashed. the aim of this study is to determine theoccu...

Abstract In terrestrial settings, the Permo-Triassic mass extinction is commonly linked to major changes in sedimentological and climatic conditions that include a switch from meandering braided fluvial systems increased aridity. We examined predominantly strata of North China reveal that, on contrary, there was little substantial change during extinction. The crisis level occurs upper Sunjiago...

Stable carbon isotopic analyses of organic carbon (d13C) in individual paleosol profiles from Permian–Triassic sequences of Antarctica reveal systematic isotopic variations with profile depth. These variations are in many cases analogous to those in modern soils, which are functions of redox conditions, soil development, and degree and type of microbial decay. In modern soils, these isotopic de...

Dating analyses based on molecular data imply that crown angiosperms existed in the Triassic, long before their undisputed appearance in the fossil record in the Early Cretaceous. Following a re-analysis of the age of angiosperms using updated sequences and fossil calibrations, we use a series of simulations to explore the possibility that the older age estimates are a consequence of (i) major ...

A partial skeleton of the aetosaur Stagonolepis sp. is the first tetrapod body fossil recovered from Upper Triassic strata in Canyonlands National Park. The specimen consists of a partial tooth and numerous disarticulated vertebrae, ribs, and scutes found in the Blue Mesa Member of the Petrified Forest Formation (Chinle Group) near Upheaval Dome. Stagonolepis is an index taxon of the Adamanian ...

Elongate (m-scale), cylindrical sandstone casts are common in the Upper Triassic Zuni Mountains Formation (basal Chinle Group) in a section near Fort Wingate, west-central New Mexico. Previous authors suggested that these features were formed by the burrowing activity of lungfish. Following abandonment of this hypothesis, it was proposed that the casts are the fossilized burrows of crayfish. We...

During the end-Permian mass extinction, marine ecosystems suffered a major drop in diversity, which was maintained throughout the Early Triassic until delayed recovery during the Middle Triassic. This depressed diversity in the Early Triassic correlates with multiple major perturbations to the global carbon cycle, interpreted as either intrinsic ecosystem or external palaeoenvironmental effects...

The Permo-Triassic archosauromorph record is crucial to understand the impact of the Permo-Triassic mass extinction on the early evolution of the group and its subsequent dominance in Mesozoic terrestrial ecosystems. However, the Permo-Triassic archosauromorph record is still very poor in most continents and hampers the identification of global macroevolutionary patterns. Here we describe crani...

We describe a new species of aetosaur, Redondasuchus rineharti, based on isolated scutes and an incomplete femur from a single locality in the Upper Triassic Redonda Formation of east-central New Mexico. R. rineharti is distinguished from R. reseri, the only other species of Redondasuchus, by its scute morphology, specifically by its large size, presence of a boss at the point of flexure and me...