In situ Lu–Hf geochronology of calcite

Calcite Dissolution: An in situ Study in the Panama Basin.

The results of an in situ study of calcite dissolution in the Panama Basin indicate that the rate of dissolution in the water column increases suddenly below a water depth of about 2800 meters. This coincides with the depth at which the calcium carbonate content of surface sediments begins to decrease rapidly or the sedimentary lysocline. Since this level of increased dissolution both in the wa...

Oligocene partial melting in the Takab metamorphic complex, NW Iran: Evidence from in situ U-Pb geochronology

U-Pb ages obtained on zircons from the investigated migmatites place new constraints on the evolution of the crustal rocks in the Takab area. SHRIMP U-Pb dating of inherited zircon in the melanosome parts of mafic migmatites from the Takab complex gives a discordant age with an upper intercept of 2961±72 Ma (MSWD=0.5) and a lower intercept of 24.2±5.7 Ma (MSWD=1.7). In the concordia diagram, th...

Quantitative laser-induced breakdown spectroscopy of potassium for in-situ geochronology on Mars

Influence of crystallographic orientation of biogenic calcite on in situ Mg XANES analyses.

Micro X-ray absorption near-edge spectroscopy at the Mg K-edge is a useful technique for acquiring information about the environment of Mg(2+) in biogenic calcite. These analyses can be applied to shell powders or intact shell structures. The advantage of the latter is that the XANES analyses can be applied to specific areas, at high (e.g. micrometre) spatial resolution, to determine the enviro...

In-situ study of organic monolayer adsorption on calcite using X-ray scattering techniques

The presence of dissolved organic compounds is known to have a profound impact upon the dissolution and growth of minerals[I], and the controlled nucleation of minerals at organic membrane surfaces is suspected to be an important feature of the formation of the exoskeletons of many invertebrate species[2]. Consequently, a fundamental understanding of the organic-mineral interface is of wide int...