Petrographic and geochemical analysis of meteorite NWA 12547 with inverse zoned chondrules

The best researched planetary system is our solar system. But even here we know very little about chemistry and composition of the bodies. In order to really explore and understand them, it is helpful to take a close look at the formation and thus the origin of everything in our solar system. Some meteorites, so called chondrites, were formed during this time and give us insights into the processes. They are therefore an important tool to understand the formation of all other bodies. A chondrite is mainly made out of chondrules which are millimeter big silicate pellets with different appearance.

One of this chondrites is the Meteorite NWA 12547. It is an ordinary L3 chondrite and is formed out of three different fragments. On consists of so-called inverse zoned chondrules. Inverse zoned chondrules are chondrules that have a pyroxene core and are surrounded by an olivine shell. This not very known silicate pellets with an inverted crystallization row is believed to have arisen from rapid cooling first which formed the pyroxene core, and then subsequent heating resulting in an olivine shell. The second fragment consists mainly of porphyric and bar-shaped chondrules. This piece was cooled slowly in a first phase and rapidly thereafter, forming first idiomorphic olivines and then small pyroxene needles in the glassy feldspar matrix. The last piece is a residual melt, with a glassy matrix which was finally cooled at about 1450 °C.