The effect of collisional erosion on the composition of Earth-analog planets in Grand Tack models: Implications for the formation of the Earth
arXiv:2210.11896 · doi:10.1016/j.icarus.2022.115325
Abstract
Impact-induced erosion of the Earth's early crust during accretion of terrestrial bodies can significantly modify the primordial chemical composition of the Bulk Silicate Earth (BSE, that is, the composition of the crust added to the present-day mantle). In particular, it can be particularly efficient in altering the abundances of elements having a strong affinity for silicate melts (i.e. incompatible elements) as the early differentiated crust was preferentially enriched in those. Here, we further develop an erosion model (EROD) to quantify the effects of collisional erosion on the final composition of the BSE. Results are compared to the present-day BSE composition models and constraints on Earth's accretion processes are provided. The evolution of the BSE chemical composition resulting from crustal stripping is computed for entire accretion histories of about 50 Earth analogs in the context of the Grand Tack model. The chosen chemical elements span a wide range of incompatibility degrees. We find that a maximum loss of 40wt% can be expected for the most incompatible lithophile elements such as Rb, Th or U in the BSE when the crust is formed from low partial melting rates. Accordingly, depending on both the exact nature of the crust-forming processes during accretion and the accretion history itself, Refractory Lithophile Elements (RLE) may not be in chondritic relative proportions in the BSE. In that case, current BSE estimates may need to be corrected as a function of the geochemical incompatibility of these elements. Alternatively, if RLE are indeed in chondritic relative proportions in the BSE, accretion scenarios that are efficient in affecting the BSE chemical composition should be questioned.
arXiv comment40 pages all included, 5 figures, accepted in Icarus
References in corpus (24)
- Disk Frequencies and Lifetimes in Young Clusters
- A low mass for Mars from Jupiter's early gas-driven migration
- Forming the cores of giant planets from the radial pebble flux in protoplanetary discs
- Collisions between Gravity-Dominated Bodies: 2. The Diversity of Impact Outcomes during the End Stage of Planet Formation
- Collisions Between Gravity-Dominated Bodies: 1. Outcome Regimes and Scaling Laws
- The timeline of the Lunar bombardment - revisited
- Highly Siderophile Elements in the Earth's Mantle as a Clock for the Moon-forming Impact
- A Shorter 146Sm Half-Life Measured and Implications for 146Sm-142Nd Chronology in the Solar System
- Cataclysm no more: New views on the timing and delivery of lunar impactors
- Lunar and Terrestrial Planet Formation in the Grand Tack Scenario
- Terrestrial planet formation from lost inner solar system material
- Geophysical and geochemical constraints on geoneutrino fluxes from Earth's mantle
- Onset of giant planet migration before 4480 million years ago
- Compositional evolution during rocky protoplanet accretion
- Geo-neutrinos and the Radioactive Power of the Earth
- The Fragility of the Terrestrial Planets During a Giant Planet Instability
- A Collisional Origin to Earth's Non-chondritic Composition?
- The excitation of a primordial cold asteroid belt as an outcome of the planetary instability
- The Asteroid Belt as a Relic From a Chaotic Early Solar System
- Collisional stripping of planetary crusts
- Subsolar Al/Si and Mg/Si ratios of non-carbonaceous chondrites reveal planetesimal formation during early condensation in the protoplanetary disk
- Effects of pebble accretion on the growth and composition of planetesimals in the inner Solar System
- Quantitative estimates of impact induced crustal erosion during accretion and its influence on the Sm/Nd ratio of the Earth
- Excavation and Melting of the Hadean Continental Crust by Late Heavy Bombardment