Laser-induced breakdown spectroscopy (LIBS) provides an alternative chemical analytical technique that obviates the issues of sample preparation and sample destruction common to most laboratory-based analytical methods. This contribution explores the capability of LIBS analysis to identify carbonate and silicate minerals rapidly and accurately. Fifty-two mineral samples (18 carbonates, 9 pyroxe...

Purely inorganic reactions of silica, metal carbonates, and metal hydroxides can produce self-organized complex structures that mimic the texture of biominerals, the morphology of primitive organisms, and that catalyze prebiotic reactions. To date, these fascinating structures have only been synthesized using model solutions. We report that mineral self-assembly can be also obtained from natura...

Carbonate anion exchange reactions with water in the uranyl-carbonate and calcium-uranyl-carbonate aqueous systems have been investigated using computational methods. Classical molecular dynamics (MD) simulations with the umbrella sampling technique were employed to determine potentials of mean force for the exchange reactions of water and carbonate. The presence of calcium counter-ions is pred...

Introduction: The recent discovery of carbonaterich outcrops in the Nili Fossae region of Mars using data returned by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument [1] as well as indications of 2-3% carbonate in alkaline soils at the Phoenix landing site [2] have brought into question the hypothesis that much of martian history has been dominated by an acidic weath...

[1] We compiled and standardized sediment trap data below 1000 m depth from 52 locations around the globe to infer the implications of the Armstrong et al. [2002] ‘‘ballast’’ model to the ratio of organic carbon to calcium carbonate in the deep sea (the rain ratio). We distinguished three forms of mineral ballast: calcium carbonate, opal, and lithogenic material. We concur with Armstrong et al....

An ~1:1 mixture of ferrihydrite and nanocrystalline akaganeite (β-FeOOH; 10–15 nm) was incubated with Shewanella putrefaciens (strain CN32) under anoxic conditions with lactate as an electron donor and anthraquinone-2,6-disulfonate (AQDS) as an electron shuttle. The incubation was carried out in a 1,4-piperazinediethanesulfonic acid (PIPES)-buffered medium, without PO4 at circumneutral pH. Iron...

The phenomenon of calcium carbonate crystal growth from aqueous solutions on surfaces widely occurs in systems where carbonate and bicarbonate ions are present, such as in domestic systems, waste and drinkable water treatment systems or industrial apparatus where water is used. Crystal growth leads to the formation of mineral scale which reduces the performance of membrane materials in equipmen...

SMMSS, K. Calcium and carbonate metabolism in the frcg (Rana temporia) during respiratory acidosis. Am. J. Physiol. 2 14(3) : 627634. 1968.-Frogs (R. temporaria) contain large deposits of calcium carbonate in the endolymphatic sacs of the inner ear. Methods are described for determining the quantities of calcium and phosphate lost from frogs made acidotic with carbon dioxide (5-200/o in oxygen)...

Fresh fracture surfaces of the martian meteorite ALH84001 contain abundant polycyclic aromatic hydrocarbons (PAHs). These fresh fracture surfaces also display carbonate globules. Contamination studies suggest that the PAHs are indigenous to the meteorite. High-resolution scanning and transmission electron microscopy study of surface textures and internal structures of selected carbonate globule...