Methane cold seep systems typically exhibit extensive buildups of authigenic carbonate minerals, resulting from local increases in alkalinity driven by methane oxidation. Here, we demonstrate that modern seep authigenic carbonates exhibit anomalously low clumped isotope values (Δ47), as much as ∼0.2‰ lower than expected values. In modern seeps, this range of disequilibrium translates into appar...

ABSTRACT-This experiment was carried out to study particle size distribution (PSD) of carbonates in soils and its effect on some calcareous soil properties in Khuzestan Province, Iran. Soil samples (n=72) were collected from different regions. To evaluate the effect of carbonates on water contents at pressure head of -1500kpa and PSD of soil samples, these properties were determined before and ...

Introduction: Preliminary analysis of the light element stable isotope geochemistry of the Tagish Lake primitive carbonaceous chondrite showed that it was a carbonate-rich meteorite containing abundant presolar grains [1, 2]. Tagish Lake seemed to be more carbon-rich than CI chondrites, with over 5 wt. % carbon distributed almost equally between organic and inorganic (mostly carbonate) componen...

Chemical fixation of CO2 has received much attention because CO2 is the most inexpensive and renewable carbon resource from the viewpoint of green chemistry and atom economy. The kinetic and thermodynamic stability of CO2 molecule presents significant challenges in designing efficient chemical transformations based on this potential feedstock. Currently, cyclic carbonates and polycarbonates are...

We report high-precision Ca/Ca measurements (2rm < 0.06&) of Hawaiian shield stage tholeiites. Our data reveal 0.3& variation in their Ca/Ca, which comprises 20% of the Ca/Ca variation observed in global carbonates. The Ca/Ca variation is correlated with Sr/Nb and Sr/Sr, and this pattern is best explained by adding up to 4% ancient carbonate into the Hawaiian plume. Mass-balance calculations sh...

soils of the arid–semiarid karaj basin in north-central iran have formed on alluvium-colluvium derived from mixed calcareous-gypsiferous marls of miocene and basic igneous rocks of holocene age. in order to characterize and classify the soils and to determine the soil-landscape relationship in the area, sixteen pedons located on different physiographic positions have been described, sampled and...

Microbial processes played a major role in mineral precipitation throughout the Earth’s history. Such processes have been widely discussed for the last few decades with regard to carbonate precipitation. Other than microbial precipitation of carbonates, in natural environments is also of great interest the potential role of microbes in the precipitation of marine barite. Regarding carbonates, o...

background: host immune system response against blood group antigens is a major problem in blood transfusions, especially forthalassemic patients. thus, an approach was proposed coating the red blood cell (rbc) surface by polyethylene glycol.objectives: this study aimed to obtain the optimal simultaneous camouflge of the major and minor antigens by activated methoxypolyethylene glycol (mpeg) wi...

carbonates are among the most common soil constituents in arid and semiarid zones. they exhibit many significant differences in their chemical and mineralogical, suite, origin, physical and micromorphological properties and consequently in their activities in soil. the differences cause different properties of calcareous soils. six profiles of aridisols and inceptisols with carbonate accumulati...