Percolation experiments, using columns filled with alternating layers of hydrated Portland cement and crushed sedimentary rocks, were conducted at PCO2 = 10 bar 60 °C. Limestone, sandstone marl representative reservoir cap rocks for a geologic CO2 storage site. The injected solution was equilibrium gypsum equilibrated the CO2. main reactions dissolution calcite that constitutes hydrotalcite por...

A study of stable isotopes (N18O, N13C) of a uranium-series dated aragonitic stalactite from Nerja Cave (Ma¤laga, southern Spain) was carried out in order to determine the conditions of deposition in isotopic equilibrium and nonequilibrium. We obtained a record of climate change from 190 000 to 160 000 years ago. A series of carbon (N13C) and oxygen (N18O) isotopes analyses have been carried ou...

Bivalve nacre is a brick-wall-patterned biocomposite of aragonite platelets surrounded by organic matter. SEM-electron back scatter diffraction analysis of nacre of the bivalve family Pteriidae reveals that early aragonite crystals grow with their c-axes oriented perpendicular to the growth surface but have their a- and b-axes disoriented. With the accumulation of successive lamellae, crystals ...

The absorption of atmospheric carbon dioxide (CO2) into the ocean lowers the pH of the waters. This so-called ocean acidification could have important consequences for marine ecosystems. To better understand the extent of this ocean acidification in coastal waters, we conducted hydrographic surveys along the continental shelf of western North America from central Canada to northern Mexico. We o...

The Atlantidae (shelled heteropods) is a family of microscopic aragonite shelled holoplanktonic gastropods with a wide biogeographical distribution in tropical, sub-tropical and temperate waters. The aragonite shell and surface ocean habitat of the atlantids makes them particularly susceptible to ocean acidification and ocean warming, and atlantids are likely to be useful indicators of these ch...

The integrity of coral-based reconstructions of past climate variability depends on a comprehensive knowledge of the effects of post-depositional alteration on coral skeletal geochemistry. Here we combine millimeter-scale and micro-scale coral Sr/Ca data, scanning electron microscopy (SEM) images, and X-ray diffraction with previously published dO records to investigate the effects of submarine...

Organisms exert remarkable controls over the minerals that form such an important part of their internal or external skeletons. For example, the microenvironment in animals that use calcium carbonate in their shells determines not only where and when crystals form but also which crystalline form, or polymorph, they will be. As illustrated in the scanning electron micrographs above, the segmente...

A geomorphic assessment of reef system calcification is conducted for past (3200 Ka to present), present and future (2010-2100) time periods. Reef platform sediment production is estimated at 569 m3 yr-1 using rate laws that express gross community carbonate production as a function of seawater aragonite saturation, community composition and rugosity and incorporating estimates of carbonate rem...

Shell repair was induced by coating the inner surfaces of gastropod shells with nail polish. In aragonitic gastropods initial deposition on the nail-polish membrane was of aragonite spherulites and, in one species, polygonal calcite crystals; later the normal crossed-lamellar structure of the shell was restored.