نتایج جستجو برای: Dolomite

تعداد نتایج: 1838  

2004
T. S. Moore R. W. Murray A. C. Kurtz D. P. Schrag

We examine the link between organic matter degradation, anaerobic methane oxidation (AMO), and sulfate depletion and explore how these processes potentially influence dolomitization. We determined rates and depths of AMO and dolomite formation for a variety of organic-rich sites along the west African Margin using data from Ocean Drilling Program (ODP) Leg 175. Rates of AMO are calculated from ...

2004
Jennifer A. Roberts Philip C. Bennett Luis A. González G. L. Macpherson Kitty L. Milliken

We report low-temperature microbial precipitation of dolomite in dilute natural waters from both field and laboratory experiments. In a freshwater aquifer, microorganisms colonize basalt and nucleate nonstoichiometric dolomite on cell walls. In the laboratory, ordered dolomite formed at near-equilibrium conditions from groundwater with molar Mg:Ca ratios of ,1; dolomite was absent in sterile ex...

2014
Fei Wang Toshihiro Kuzuya Shinji Hirai Jihua Li Te Li

The decomposition of dolomite into CaO and MgO was performed at 1073 K in vacuum and at 1273 K in an Ar atmosphere. The dolomite calcined in vacuum was found to have a higher specific surface area and a higher micropore volume when compared to the dolomite calcined in the Ar atmosphere. These pyrolysis products of dolomite were reacted with CO2 at 673 K for 21.6 ks. On the absorption of CO2, th...

2012
JOHN M. RIVERS Tracy Frank

Anomalously saline waters in Ocean Drilling Program Holes 1127, 1129, 1130, 1131 and 1132, which penetrate southern Australian slope sediments, and isotopic analyses of large benthic foraminifera from southern Australian continental shelf sediments, indicate that Pleistocene–Holocene meso-haline salinity reflux is occurring along the southern Australian margin. Ongoing dolomite formation is obs...

2008
SARAH K. CARMICHAEL JOHN M. FERRY WILLIAM F. McDONOUGH

Replacement dolomite in the Latemar carbonate buildup, northern Italy, formed when limestone was infiltrated by and reacted with Mg-rich fluid. It occurs in discrete bodies in sharp contact with unreacted limestone. The dolomite developed in a nearly orthogonal lattice of vertical columns (replacement of limestone breccia pipes) and sheets (replacement along fractures and limestone-dike contact...

2012
M. Turpin E. Kohler

Empirical Calibration for Dolomite Stoichiometry Calculation: Application on Triassic Muschelkalk-Lettenkohle Carbonates (French Jura) — This study concerns an approach for dolomite quantification and stoichiometry calculation by using X-ray diffractometry coupled with cell and Rietveld refinements and equipped with a newly substantial database of dolomite composition. A greater accuracy and pr...

2015
Juan Diego RoDRiguez-Blanco Samuel Shaw liane g. Benning

The direct crystallization of dolomite from an aqueous solution at temperatures between 60–220 °C was followed in situ through time-resolved synchrotron-based energy-dispersive X-ray diffraction combined with offline high-resolution imaging, X-ray diffraction, and infrared spectroscopy. Crystalline CaMg(CO3)2 phases form through a three-stage process. In the first stage, a nanoparticulate magne...

2007
PATRICK MEISTER DANIEL P. SCHRAG

Early diagenetic dolomite beds were sampled during the Ocean Drilling Programme (ODP) Leg 201 at four reoccupied ODP Leg 112 sites on the Peru continental margin (Sites 1227/684, 1228/680, 1229/681 and 1230/685) and analysed for petrography, mineralogy, dC, dO and Sr/Sr values. The results are compared with the chemistry, and dC and Sr/Sr values of the associated porewater. Petrographic relatio...

Journal: :Zeitschrift fur Naturforschung. C, Journal of biosciences 1993
S Scheller W Krol K Skirmuntt G Zydowicz J Shani

Dolomite, a mineral composed of magnesium and calcium carbonates, potentiates the antitumoral activity of bleomycin: While 40 days after inoculation, no mice survived the Ehrlich ascites tumor burden, 44% of them survived it after bleomycin treatment, and 63% after a simultaneous treatment of bleomycin and dolomite. The beneficial antitumor effect of dolomite is probably related to its high con...

Journal: :Bioresource technology 2012
R Li Z P Zhong B S Jin A J Zheng

Fast pyrolysis of rice husk was performed in a spout-fluid bed to produce water-soluble organics. The effects of mineral bed materials (red brick, calcite, limestone, and dolomite) on yield and quality of organics were evaluated with the help of principal component analysis (PCA). Compared to quartz sand, red brick, limestone, and dolomite increased the yield of the water-soluble organics by 6-...

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