The highest rates of global organic carbon burial (up to 6.5 × 10 mol/Myr) over the past half billion years occurred during the Carboniferous–Permian (330–260 Myr), in large part because of the accumulation and burial of peat in broad tropical lowland basins (1). Atypical rates of organic carbon sequestration led to low atmospheric pCO2 and anomalously high pO2 (Fig. 1), which in turn triggered...

The upper part of Shirgesht (UPS) and lower part of Niur (LPN) formations (Ordovician-Silurian) consist of sandstone, shale and limestone, respectively. The petrography and geochemical analysis conducted to evaluate provenance of siliciclastic deposits in order to understand the paleogeography of Central Iran during the Early Paleozoic time. This study shows that quartz and K-feldspar are the m...

the igneous dykes are a small mafic rock unit exposed in the south gorgan of eastern alborz, north iran. these mafic dykes are intruded in the middle–upper paleozoic sedimentary and metamorphic rocks units representing a part of the north gondwana province. the studied samples were collected from various locations along the exposed bodies. thin sections of these rocks show medium to coarse grai...

This special issue is based on a theme session convened at the Annual Meeting of the Geological Society of America held in Denver, Colorado, in October 2004. The theme session brought together a diverse group of scientists interested in the chemistry of Precambrian and Paleozoic oceans and its role in climatic and evolutionary events. The contributors to this issue make use of a wide range of i...

To understand how extant viruses interact with their hosts, we need a historical framework of their evolutionary association. Akin to retrovirus or hepadnavirus viral fossils present in eukaryotic genomes, bracoviruses are integrated in braconid wasp genomes and are transmitted by Mendelian inheritance. However, unlike viral genomic fossils, they have retained functional machineries homologous ...