Processes involved in the formation of extraterrestrial matter: an update considering ALL data

MARIA EUGENIA VARELA

La Plata

Taller; LACAME08; 2008

Current models of formations of the great diversity of rocks in the early solar system, are not capable to predict and explain a variety of observations made on these rocks.  There is a general consensus on the classification of the large diversity of meteorites into ?unfractionated? (relative abundances of chemical elements ~ solar abundances), and ?fractionated? (elemental abundances non-solar). The ?unfractionated? meteorites ?the chondrites- constitute the majority and are considered to represent the ?primitive? building blocks of the terrestrial planets. By analogy with terrestrial rocks, the ?fractionated? meteoritic rocks (achondrites, stony-irons and irons) are considered to be of planetary origin, having formed by chemical fractionation from a chondritic source rock by a process similar to smelting (separation of metals from silicates) and additional melting and crystallization processes (?geochemical? processing). However, these consensuses and strong belief can create inadequate models, based on our home planet.