Ti, V and Cr valences in olivines of CV3 chondrites: insights into chondrules formation

Chondrules (mm-size igneous spherules made of silicates) are the major components of primitive meteorites. Their origin is still debated: did they derive from planets or did they directly form in a mysterious nebular environment? Hence, deciphering their condition of formation is crucial for understanding the Solar system’s evolution. Recently, some clues based on chemical and isotopic measurements have promoted nebular models. Although we lack data on their formation’s environments, a promising approach would be to measure the oxygen fugacity (fO2) recorded during their formation (fO2 is dependent on the chemical environment). Reducing conditions are typical of nebular environments (log fO2~IW-7, IW being the Fe-FeO redox buffer) while planetary impacts generate oxidizing conditions (log fO2>IW). Here we propose to determine the valences of Ti, V and Cr in olivine grains contained in CV3 chondrites to estimate fO2 values and determine the environment of chondrules’ formation.