The Tarda Meteorite: A Window into the Formation of D-type Asteroids

Abstract Dynamic models of solar system evolution suggest that D-type asteroids formed beyond Saturn's orbit and represent invaluable witnesses the prevailing conditions in outer system. Here, we report a comprehensive petrographic isotopic characterization carbonaceous chondrite Tarda, recent fall recovered Moroccan Sahara. We show Tarda shares strong similarities with D-type-derived Tagish Lake, implying represents rare sample asteroids. Both Lake are characterized by presence 16 O-rich chondrules chondrule fragments, high C/H ratios, enrichments deuterium, 15 N, 13 C. By combining our results literature data on chondrites related to C-type asteroids, 4.56 Gy ago was large-scale oxygen homogeneities (i) water–ice grains accreted (ii) gas controlling formation FeO-poor chondrules. Conversely, zone which significantly enriched deuterium relative regions features likely inherited from unprocessed, D-rich, molecular-cloud materials.