Geologic investigations of the Arabian-Nubian Shield (ANS) are supported by a valuable, expanding dataset of geochronologic ages and isotopic analyses. U-Pb zircon SIMS, TIMS, and evaporation data provide robust temporal control on depositional, volcanic, and intrusive events. Nd, Sr, O and, increasingly, Hf isotopic studies provide insights into magma sources and constraints on crustal recycli...

Abstract The Longshou Shan of western China is the northern backstop Cenozoic Himalayan-Tibetan orogen and occupies a key linkage between Tarim continent North craton which separate pre-Cenozoic Tethyan orogenic system Central Asian system. Therefore, Paleoproterozoic–Paleozoic evolution this region critical to understanding extent overprinting deformation, construction Eurasian continent, rela...

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...

Abstract The Proterozoic–Phanerozoic tectonic evolution of the Qilian Shan, Qaidam Basin, and Eastern Kunlun Range was key to construction Asian continent, understanding paleogeography these regions is critical reconstructing ancient oceanic domains central Asia. This issue particularly important regarding North China-Tarim continent South China craton, which have experienced significant late N...

The N/NNE-striking Aravalli Delhi Fold Belt (ADFB) and the E-striking Central Indian Tectonic Zone (CITZ) converge at Godhra-Chhota Udepur (GC) sector, west-central India. Analyses of mesoscale deformation structures metamorphic phase equilibria in basement supracrustal rocks are integrated with geochronological-geochemical data (accompanying article) to address dynamics Early Neoproterozoic CI...

Siliciclastic rocks of the upper Byrd Group in the Transantarctic Mountains record rapid denudation and molasse deposition during Ross orogenesis along the early Paleozoic convergent margin of Gondwana. These rocks, which stratigraphically overlie Lower Cambrian Byrd carbonate deposits, are dominated by fresh detritus from proximal igneous and metamorphic sources within the Ross Orogen. Biostra...

The temperature and salinity histories of the oceans are major environmental variables relevant to the course of microbial evolution in the Precambrian, the bage of microbesQ. Oxygen isotope data for early diagenetic cherts indicate surface temperatures on the order of 55–85 8C throughout the Archean, so early thermophilic microbes (as deduced from the rRNA tree) could have been global and not ...

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...

SYNOPSIS. The Cambrian radiation is that key episode in the history of life when a large number of animal phyla appeared in the fossil record over a geologically short period of time. Over the last 20 years, scientific understanding of this radiation has increased significantly. Still, fundamental questions remain about the timing of the radiation and also the tempo of evolution. Trilobites are...

• Upper Ediacaran–lowermost Cambrian mudstones from northern Norway were studied. Ediacara-type macrofossils are associated with a well-oxygenated environment. Neodymium isotopic data indicate terrigenous detritus old continental crust. Brief provenance switch during post-Gaskiers time. Rb–Sr whole-rock isotope system was reset the Scandian Orogeny. The Digermulen Peninsula in northeastern Finn...