The chemical, morphological and mineralogical properties of two Enon sandy loam (fine, mixed, thermic Ultic Hapludalfs) soilsaprolite profiles, one formed on gabbro and the other on metagabbro, are compared. Clay skins are scarce and stress cutans common in the argillic horizons of these soils. Iron-manganese concretions are concentrated in soil horizons immediately above the argillic horizons....

A common view of the thermal and shock histories of ordinary-chondrite (OC) parent bodies is that, for the most part, thermal and shock metamorphism were distinguishable and successive events; e.g., the decay of 26 Al heated chon-dritic planetesimals and subsequent impacts produced various shock effects. Although collisions have long been acknowledged as capable of producing significant heating...

1 , C. M. Pieters 1 , M. D. Dyar 2 , K.A. Milam 3 , 1 Dept. of Geological Sciences, Brown University, Providence RI 02912, [email protected], [email protected], 2 Department of Astronomy, Mount Holyoke College, 50 College St., South Hadley, MA 01075, [email protected], 3 Department of Geological Sciences, Ohio University, 316 Clippinger Laboratories, Athens, OH 45701, [email protected].

We present results from an ion microprobe study of REE-doped and natural concentration plagioclase-basalt run products of Drake (1972) that carries on from our earlier study (Bindeman et al., 1998). The goals of this work are (1) to determine plagioclase/melt partition coefficients for all REE for four analyzed plagioclase compositions (An40–80); and (2) to determine whether doping with REE inf...

Introduction: Ferroan anorthosite is a dominant rock type in the lunar highland crust. Currently it is thought that the crust was formed by the crystallization and flotation of plagioclase from a global magma ocean [1,2]. This hypothesis of the lunar crust formation was made based on numerous analyses of Apollo and Luna lunar samples of ferroan anorthosites. Nevertheless these samples are now k...

We propose an empirically derived model that estimates the extent of reaction for albitization of plagioclase as a function of time, grain surface area, and temperature from 0 to 200°C. We use a kinetic formulation independent of pressure, and consistent with the Rate Law, which quantifies the dependence of the reaction rate on the initial concentration of the reacting material, and the Arrheni...

Introduction: In heavily shocked stony meteorites, plagio-clase in the host rock has transformed into glass (maskelynite) in a solid-state reaction. So far, the formation pressure of maske-lynite has been estimated only based on dynamic high-pressure experiments [1]. However, duration of pressure in laboratory shock experiments is significantly smaller (10-6 sec) than that in meteorite parent b...