Fig. 1. Chronometric ages and the history of NWA 7034.

(A) Summary of NWA 7034 radiometric ages. The horizontal widths of the boxes are defined by the maximum and minimum ages obtained from a given method plus or minus the associated 2σ uncertainties, respectively. U-Th-Sm/He, ⁴⁰Ar/³⁹Ar, and U-Pu/Xe ages are from this study. U-Pb in phosphate ages are from the studies of McCubbin et al. (6), Yin et al. (8), and Bellucci et al. (9). U-Pb in young zircon ages are from the studies of McCubbin et al. (6), Tartèse et al. (7), and Yin et al. (8). U-Pb in old zircon ages are from the studies of Humayun et al. (2), McCubbin et al. (6), Tartèse et al. (7), and Yin et al. (8). U-Pb in baddelyite ages are from Tartèse et al. (7). Sm-Nd data are from Nyquist et al. (5). The whole-rock ⁴⁰Ar/³⁹Ar age from the study of Lindsay et al. (11) is included with the data from this study. ⁴⁰Ar/³⁹Ar ages from feldspars are not shown. (B) Chronology of major events in the history of NWA 7034 inferred from isotopic measurements (see main text for additional details). (i) The source lithology formed at 4420 ± 70 Ma. (ii) The source lithology was subject to impact events that created ancient impact melt rocks at ~4400 Ma. (iii) After almost 3000 Ma of quiescence, the terrain experienced several hundred million years of thermal metamorphism from 1500 to 1200 Ma. (iv) Following metamorphism, another ~1000 Ma of quiescence prevailed until brecciation at 225 Ma or later. (v) A final impact event after brecciation ejected NWA 7034 from the surface of Mars.