Convection and crystal settling in sills

Article Abstract:

Convection does not affect the solidification of sill-like magma bodies, while gravity settling slightly modifies the intrusion of olivine in the bodies. The distribution and depth of olivine phenocrysts in the magma sills are determined to substantiate the insufficiency of convection and gravity in the settling of sills. However, sills can be formed from the intermittent introduction of magma materials allowing the continuous cooling, settling and accumulation of magma.

Observations, Sills (Geology), Density currents

---

Hydrothermal alterations in the Echassieres granitic cupola (Massif Central, France)

Article Abstract:

The hydrothermal history of the albite-lepidolite granite in Echassieres is presented. Three steps are distinguished: magmatic, early and late hydrothermal alteration stages. Moreover, the magmatism and hydrothermal stages are both spatially and temporally related. Then, a thermodynamic model is proposed to explain the different stability fields of the successive alteration minerals and to calculate the chemical properties of the hydrothermal solutions.

Analysis, France, Granite

---

Two-stage contamination during crustal assimilation: isotopic evidence from volcanic rocks in eastern Nevada

Article Abstract:

Contamination of mafic magmas in the middle crust occur in two main stages: contamination with a partial melt of pelitic crust and then assimilation of the residue of the melting event. Consequently, there is bulk assimilation occurring in two steps, and late stages of magmatism are dominated by crystal fractionation. Lastly, the crustal source for the principal contaminants is pelitic and part of a Proterozoic crustal province.

Nevada

Similar abstracts:

• Abstracts: Comment and reply. Modeling the behavior of the continental mantle lithosphere during plate convergence. Island-arc basalt alkali ratios: constraints from phengite-fluid partitioning experiments
• Abstracts: Strontium and neodymium isotopic study of the western Mogollon-Datil volcanic region, New Mexico, USA. Ce and Nd isotope geochemistry on island arc volcanic rocks with negative Ce anomaly: existence of sources with concave REE patterns in the mantle beneath the Solomon and Bonin island arcs

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.