Timescale and conditions of formation of the first solids of the solar system

Séminaire IPAG de Yves Marrocchi (Centre de Recherches Pétrographiques et Géochimiques - Nancy), jeudi 13 février 2020, 11h00, IPAG seminar room

Chondrites are leftover solids from the evolution of the solar protoplanetary disk 4.56 Gyr ago. They are composed of varying proportions of four main components : refractory inclusions, chondrules, Fe-Ni metal and matrix material. These materials were subsequently accreted together to form the asteroidal parent bodies that represent the source of unequilibrated meteorites. Refractory inclusions are high temperature assemblages composed of crystalline silicates and oxides rich in calcium and aluminum. They are the oldest recognized objects in Solar System with an absolute age of 4.5685 Gyr. Chondrules are silicate spherules that represent the most abundant solid formed during the evolution of the protoplanetary disk. However, due to a fragmentary understanding of processes involved, the timescale and the conditions of formation of these primordial solids remains very enigmatic and controversial. During this seminar, I will present new isotopic results that allows the condensation and agglomeration timescales of the first solids of the solar system to be quantified. By coupling petrographic observations and isotopic measurements, I will also discuss how recycling processes led to the formation of chondrules. These results will be used to discuss the conditions of formation and evolution of the solar protoplanetary disk.