a micropaleontological study has been carried out on the samples collected from the sarv abad section, the oldest and only known jurassic sedimentary rocks cropping out in the moghan area. studied sequence consists of carbonates bounded at both base and top by clastic deposits. studied carbonate deposits provide an assemblage of benthic foraminifera as well as calcareous algae. the stratigraphi...

Sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) have been studied extensively in marine sediments because of their vital roles in both sulfur and carbon cycles, but the available information regarding the highly diverse SRB and SOB communities is not comprehensive. High-throughput sequencing of functional gene amplicons provides tremendous insight into the structure and func...

Late Holocene paleoclimate records from coastal regions are important for understanding long-term variability of hurricane activity. Here we present a nearly 4000-year record of severe storm landfalls and environmental changes based on organic geochemical proxies (OGPs) preserved in sediment cores from two coastal lakes in northwest Florida. Our analysis shows that there are significant variati...

Cadmium concentrations were measured at 49 littoral sites in 38 lakes distributed over 350,000 km2 in the provinces of Quebec and Ontario, both in the abiotic environment (oxic sediments and overlying water, diagenetic iron oxyhydroxide deposits on Teflon collectors) and in the soft tissues of the freshwater bivalve Anodonta grandis collected along a Cd contamination gradient. Concentrations of...

An appealing strategy for reconstructing the timing and tempo of paleoenvironmental change from sedimentary strata is to linearly interpolate between marker beds known age. This method requires significant assumptions, but more advanced age modeling methods are usually not feasible. We used experiments explore how changes in processes invalidate these assumptions affect estimates time strata. W...

Dinoflagellates constitute a large proportion of the planktonic biomass from marine to freshwater environments. Some species produce a preservable organic-walled resting cyst (dinocyst) during the sexual phase of their life cycle that is an important link between the organisms, the environment in which their parent motile theca grew, and the sedimentary record. Despite their abundance and wides...

The Central Atlantic Magmatic Province (CAMP) has long been proposed as having a causal relationship with the end-Triassic extinction event (∼201.5 Ma). In North America and northern Africa, CAMP is preserved as multiple basaltic units interbedded with uppermost Triassic to lowermost Jurassic sediments. However, it has been unclear whether this apparent pulsing was a local feature, or if pulses...

Molecular microbial ecology studies have revealed remarkable prokaryotic diversity in extreme hydrothermal marine environments. There are no comparable reports of culture-independent surveys of eukaryotic life in warm, anoxic marine sediments. By using sequence comparisons of PCR-amplified small subunit ribosomal RNAs, we characterized eukaryotic diversity in hydrothermal vent environments of G...

The rock strata of Cretaceous sedimentary system represented by Aptian to Maastrichtian age occurs as isolated patches outcropping in the western margin of the Cauvery Basin bordering the Archaean granite and gneiss basement. The Cretaceous system is well known as “Cretaceous of Trichinopoly” containing diverse fauna and flora including dinosaur remains, commercially exploitable limestone, lign...