Depth of Origin of the Peak (Inner) Ring in Lunar Impact Basins

Abstract

Numerical modeling of the peak‐ring basin formation showed that the peak‐ring forms from the material that is part of the central uplift outwardly thrust over the inwardly collapsing transient crater rim. Simulations of the lunar basin formation showed that the peak or inner ring in peak ring or multiring basins, respectively, is composed of the overturned crust and deep‐seated material, possibly from the upper mantle. Numerical impact simulations were used to trace the depth of origin of material exposed within the peak (or inner) ring. We estimate the scaling trends between basin size and the depth of origin of material exposed within the ring. We also report on the likely crust, mantle, and projectile abundances exposed within the ring. Quantifying the excavation depths during the formation of the peak or inner ring provides a step toward understanding the lunar crust and mantle stratigraphy.

Spinel assemblages in lunar meteorites Graves Nunataks 06157 and Dhofar 1528: Implications for impact melting and equilibration in the Moon's upper mantle

“…Miljković et al. () showed that the inner peak rings of the 1076 km diameter Crisium and 923 km diameter Serenitatis multi‐ring impact basins (Neumann et al. ) could expose material that originated from mean depths of ~70 km and ~90 km, respectively.…”

“…This contrasts with results from Hammond et al (2009) who suggested an excavation depth of 350 to 380 km for South Pole Aitken. Miljkovi c et al (2017) showed that the inner peak rings of the 1076 km diameter Crisium and 923 km diameter Serenitatis multi-ring impact basins (Neumann et al 2015) could expose material that originated from mean depths of~70 km and~90 km, respectively.…”

“…; Miljković et al. , ). However, almost 50 years of petrologic studies of lunar rocks have produced little concrete evidence for a sample that represents the lunar mantle (with the possible exception of Wang et al.…”

“…Cratering mechanics suggest that the largest lunar impact basins should have excavated rocks from the upper mantle that reaches to an approximate depth of 560 km Grieve 1998a, 1998b;Wieczorek et al 2006;Potter et al 2012;Miljkovi c et al 2015Miljkovi c et al , 2017. However, almost 50 years of petrologic studies of lunar rocks have produced little concrete evidence for a sample that represents the lunar mantle (with the possible exception of Wang et al [2015]; who identified dunite 72415 as a primary mantle cumulate based on Fe-isotopic evidence).…”

Compositional Variations in the Vicinity of the Lunar Crust‐Mantle Interface From Moon Mineralogy Mapper Data

“…According to Baker and Head (2015) and Miljković et al (2017), the maximum depth of melting for peak ring basins cannot be taken as a proxy for estimating the depth of origin of the material exposed in the peak rings. LCP is observed in the central peaks of two of the central peak craters supposedly tapping the deepest material in the crater selection (Maginus and Clavius craters).…”