Constraining the cratering chronology of Vesta
نویسندگان
چکیده
Vesta has a complex cratering history, with ancient terrains as well as recent large impacts that have led to regional resurfacing. Crater counts can help constrain the relative ages of different units on Vesta's surface, but converting those crater counts to absolute ages requires a chronology function. We present a cratering chronology based on the best current models for the dynamical evolution of asteroid belt, and calibrate it to Vesta using the record of large craters on its surface. While uncertainties remain, our chronology function is broadly consistent with an ancient surface of Vesta as well as other constraints such as the bombardment history of the rest of the inner Solar System and the Ar–Ar age distribution of howardite, eucrite and diogenite (HED) meteorites from Vesta. & 2014 Elsevier Ltd. All rights reserved.
منابع مشابه
The chronostratigraphy of protoplanet Vesta
In this paper we present a time-stratigraphic scheme and geologic time scale for the protoplanet Vesta, based on global geologic mapping and other analyses of NASA Dawn spacecraft data, complemented by insights gained from laboratory studies of howardite–eucrite–diogenite (HED) meteorites and geophysical modeling. On the basis of prominent impact structures and their associated deposits, we pro...
متن کاملIn-situ Ldrims Geochronometry for the Moon and Mars
Introduction: We have developed and tested a bench-top version of a Laser Desorption Resonance Ionization Mass Spectrometer (LDRIMS) instrument for rubidium-strontium (Rb-Sr) geochronology. Current results are sufficient for radiometric dating (±0.1%), though we are working on increasing the precision of the measurement to a more optimal precision for geochronology of ±0.02%. Currently, a sampl...
متن کاملRelative chronology of crust formation on asteroid Vesta: Insights from the geochemistry of diogenites
The eucrites and diogenites are meteorites that probably originate from asteroid 4-Vesta. The upper part of the crust of this body is certainly composed of eucrites which are basaltic or gabbroic rocks. Diogenites are ultramafic cumulates whose relationships with eucritic lithologies are unknown. Here, we show that the orthopyroxenes of some diogenites display very deep negative Eu anomalies (E...
متن کاملPossible long-term decline in impact rates 1. Martian geological data
Quantin et al. [Quantin, C, Allemand, P., Mangold, N., Delacourt, C, 2004a. Icarus 172, 555-572] tabulated crater count data for 56 landslides along the walls of Valles Marineris. Under the assumption of a constant cratering rate after about 3 Gyr ago, as used in the 1999-2005 iterations of the crater chronology isochron system of Hartmann, and in the Hartmann and Neukum system, these data indi...
متن کاملRED Meteorites and Their Relationship to the Geology of Vesta and the Dawn Mission Harry
Howardite-eucrite-diogenite (HED) meteorites, thought to be derived from 4 Vesta, provide the best sampling available for any differentiated asteroid. However, deviations in oxygen isotopic composition from a common mass-fractionation line suggest that a few eucrite-like meteorites are from other bodies, or that Vesta was not completely homogenized during differentiation. The petrology and geoc...
متن کامل