ERINGAITE-BEARING ULTRA-REFRACTORY CAI A. N. Krot, K. Nagashima, C. Ma, G. J. Wasserburg. HIGP, U. Hawai‘, USA. CalTech, USA. Introduction: Forsterite-bearing Type B (FoB) Ca,Al-rich inclusions (CAIs) are a rare type of coarse-grained igneous CAIs found almost exclusively in CV3 chondrites [1–5]. Here we describe the mineralogy, petrography, and oxygen-isotope compositions of a FoB CAI Al-2 fro...

Interstellar matter is known to be strongly irradiated by radiation and several types of cosmic ray particles. Simulated interstellar matter, such as forsterite Mg2SiO4, enstatite MgSiO3 and magnesite MgCO3 has been irradiated with the Co gamma-rays in liquid nitrogen, and also irradiated with fast neutrons at 10 K and 70 K by making use of the low-temperature irradiation facility of Kyoto Univ...

Data determined using a multianvil press are given for liquidus phase relations in the system diopside – forsterite – enstatite (CaMgSi2O6 – Mg2SiO4 – MgSiO3) and extend for a limited distance into the larger ternary system diopside – forsterite – quartz at 5.1 GPa. In the system diopside–enstatite, which cuts across the system diopside – forsterite – quartz and divides it into two smaller tern...

Forsterite and clinoenstatite in type IAB chondrules from the Murchison CM carbonaceous chondrite have been partially serpentinized, and the mechanisms of their alteration reveal crystallographic and microstructural controls on the reaction of silicate minerals with parent body aqueous solutions. Grains of forsterite were altered in two stages. Narrow veinlets of Fe-rich serpentine formed first...

Introduction: Many chondrules clearly contain relict grains that result from incomplete melting of precursor material. Most discussions of relict grains have focused on grains that are easy to identify because they have compositions significantly different from their host chondrules, including forsterite in type II chondrules and dusty olivine in type I chondrules [1]. However, in order to full...

Hugoniot equation of state measurements have been performed on pure synthetic single-crystal forsterite (Mg•SiO4) in the pressure range 70-160 GPa (0.7-1.6 Mbar). These and earlier data for polycrystalline forsterite are compared with theoretical Hugoniots for the assemblages 2MgO (rocksalt) + SiO: (stishovite) and MgO (rocksalt) + MgSiO8 (perovskite). The densities attained by single-crystal f...

Ten reversed brackets of aqueous silica concentration in equilibrium with enstatite (Mg2Si2O6) and forsterite (Mg2SiO4) were determined at 700 to 900°C and 4.35 to 14 kbar. Silica solubilities were measured by a weight loss-weight gain method and by approaching equilibrium from higher and lower silica concentrations. Both single-crystal and fine-grained synthetic enstatite and forsterite starti...

We present quantitative laboratory studies that simulate the effect of redeposition of impact-ejecta on mineral surfaces. We produced deposits of natural olivine (Fo90) and forsterite on olivine and forsterite powder samples by ns-pulsed laser ablation. The deposits produce changes in the optical reflectance (0.66–2.5 μm). We show that significant darkening and reddening of the surface occurs w...

Forsterite (Mg2SiO4) is one of the major planetary materials, and its behavior under extreme conditions is important to understand the interior structure of large planets, such as super-Earths, and large-scale planetary impact events. Previous shock compression measurements of forsterite indicate that it may melt below 200 GPa, but these measurements did not go beyond 200 GPa. We report the sho...