Evidence for late formation and young metamorphism in the Achondrite Nakhla
- 1 May 1974
- journal article
- Published by American Geophysical Union (AGU) in Geophysical Research Letters
- Vol. 1 (1) , 23-26
- https://doi.org/10.1029/gl001i001p00023
Abstract
We have determined an age T=1.37 AE for Nakhla and an initial 87Sr/86Sr, I = 0.7023. A rather thorough Sr equilibration took place at this time between all the phases of this meteorite, but there is clear evidence of somewhat incomplete isotopic equilibrium during the 1.37 AE event, which is not consistent with the derivation of Nakhla from a magma at this time. Nakhla has a young model age of 3.6‐2.9 AE which requires that gross differentiation processes for its parent body occur between 3.6 and 1.37 AE, significantly later than 4.6 AE. The most reasonable model is that Nakhla formed as an igneous rock at ∼3 AE and was metamorphosed at 1.37 AE. Several similarities exist between the Nakhla parent planet and the Earth and indicate the existence of other objects with close terrestrial chemical affinities.This publication has 13 references indexed in Scilit:
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