for study of different types of stromatolites, their modes of growth and their relation to sequence stratigraphy within the derinjal formation, three stratigraphic sections at dahuieh, gatkueih and gazueih in se and e of zarand (nw kerman), were measured and sampled with thickness of 160, 140 and 130 meter, respectively. modes of sediment accretion, trapping and binding of sedimentary grains, t...

Although palaeontological evidence from exceptional biota demonstrates the existence of diverse marine communities in the Early Cambrian (approx. 540-520 Myr ago), little is known concerning the functioning of the marine ecosystem, especially its trophic structure and the full range of ecological niches colonized by the fauna. The presence of a diverse zooplankton in Early Cambrian oceans is st...

There was a major diversification known as the Ordovician Radiation, in the period immediately following the Cambrian. This event is unique in taxonomic, ecologic and biogeographic aspects.While all of the phyla but one were established during the Cambrian explosion, taxonomic increases during the Ordovician were manifest at lower taxonomic levels although ordinal level diversity doubled. Marin...

Lobopodians, a nonmonophyletic assemblage of worm-shaped soft-bodied animals most closely related to arthropods, show two major morphotypes: long-legged and short-legged forms. The morphotype with stubby, conical legs has a long evolutionary history, from the early Cambrian through the Carboniferous, including the living onychophorans and tardigrades. Species with tubular lobopods exceeding the...

The Upper Ediacaran to Lower Cambrian of the Sichuan Basin in South China has long been considered be dominated by shallow-water deposition. Hydrocarbon exploration, however, revealed that a NW-SE trending intraplatform trough formed basin during same period. Although different models have proposed, formation and evolution are still not fully understood. In this study, we investigate both origi...

This study reviews the available data on Phanerozoic plume activity (Large Igneous Provinces (LIP’s) size and frequency) geochemistry of their igneous rocks. A major goal this review is to try find changes in intensity mantle plumes linked Earth’s evolution galactic seasonality that was supposed authors’ previous publications. The indicate Cambrian–Ordovician Jurassic–Cretaceous summers were as...

The study of trace fossils, the fossilized remains of animal behavior, reveals interesting parallels with recent research in behavior-based robotics. This article reports robot simulations of the meandering foraging trails left by early invertebrates that demonstrate that such trails can be generated by mechanisms similar to those used for robot wall-following. We conclude with the suggestion t...

Sponge remains have been identified in the Early Vendian Doushantuo phosphate deposit in central Guizhou (South China), which has an age of approximately 580 million years ago. Their skeletons consist of siliceous, monaxonal spicules. All are referred to as the Porifera, class Demospongiae. Preserved soft tissues include the epidermis, porocytes, amoebocytes, sclerocytes, and spongocoel. Among ...

THE SANDU FORMATION, consisting mainly of mudstone and marl, crops out sparsely in Guole Township, Jingxi County, southwestern Guangxi Province, China (Fig. 1). It yields a rich fauna of trilobite fossils, including species belonging to Shergoldia, Tamdaspis and Sinosaukia, which together indicate a late Furongian (latest Cambrian) age. These fossils are both abundant and well preserved. A larg...