Chondrule cooling rates inferred from diffusive profiles in metal lumps from the Acfer 097 CR2 chondrite

An Extreme O-rich Chondrule from Acfer 214 Ch Chondrite

Introduction: Oxygen isotope systematics between 16 O-rich and –poor reservoirs is well known in the solar system [1]. Since O is account for over 50 atomic % of terrestrial planets and also dominant in the solar nebular gas next to H and He [2], range and distribution of the systematics is an important tracer recording origin and global evolution of early solar system. The 16 O-rich endmenber,...

Presolar Fe Oxide from the Acfer 094 Carbonaceous Chondrite

Vesiculation rates of obsidian domes inferred from H2O concentration profiles

[1] Explosivity of rhyolite domes depends on bubble nucleation and growth. To understand these processes, we measure millimeter-scale variations in H2O by synchrotron Fourier transform infrared (FTIR) spectromicroscopy on interlayered obsidian-pumice samples. The H2O contents of all samples are above the 1-atm solubility value ( 0.10wt.%) and decrease systematically towards vesicular zones, ind...

Continued Characterization of Presolar Silicate Grains from the Acfer 094 Carbonaceous Chondrite

Introduction: Among circumstellar grains produced around O-rich evolved stars, silicate grains are the most abundant [1]. Until recently, the identification of presolar silicate grains in extraterrestrial materials proved difficult due in part to their destruction by parent body processes, requiring analysis of very primitive samples, and to the experimental challenge presented by their submicr...

DISCOVERY OF METEORITIC LAKARGIITE (CaZrO3), A NEW ULTRAREFRCTORY MINERAL FROM THE ACFER 094 CARBONACEOUS CHONDRITE

Introduction: During a nano-mineralogy investigation of the Acfer 094 carbonaceous chondrite, lakargiite (CaZrO3) was identified as submicrometer inclusions in an isolated hibonite grain in section USNM 7233-1. The hibonite grain is described in Simon and Grossman [1]. Lakargiite is a recently found perovskite-group mineral from hightemperature skarns in ignimbrites of the Upper-Chegem volcanic...