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Silicon Isotope Evidence Against an Enstatite Chondrite Earth

2012; American Association for the Advancement of Science; Volume: 335; Issue: 6075 Linguagem: Inglês

10.1126/science.1219509

1095-9203

Caroline Fitoussi, Bernard Bourdon,

Planetary Science and Exploration

Building Blocks of Earth Earth formed from an explosive and energetic series of collisions that accreted material over millions of years. Comparisons between rocks from Earth's interior and more primitive extraterrestrial samples can help tease apart the composition of Earth's starting material; however, discrepancies between the abundance of certain elements or their isotope ratios often obscure their origin. Fitoussi and Bourdon (p. 1477 , published online 1 March) analyzed the silicon isotopes of a suite of rocks from chondritic meteorites and the Moon to reconcile some of the previous models. By tuning Earth accretion models to account for these Si isotope signatures, enstatite chondrites could be ruled out as the sole end-member composition for bulk Earth. Instead, a heterogeneous mixture of several types of chondritic meteorites is more likely.