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Global characteristics of porosity and density stratification within the lunar crust from GRAIL gravity and Lunar Orbiter Laser Altimeter topography data
Author(s) -
Han ShinChan,
Schmerr Nicholas,
Neumann Gregory,
Holmes Simon
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl059378
Subject(s) - geology , altimeter , orbiter , crust , stratification (seeds) , impact crater , lunar orbit , astrobiology , geophysics , geodesy , spacecraft , aerospace engineering , seed dormancy , botany , germination , physics , dormancy , engineering , biology
The Gravity Recovery and Interior Laboratory (GRAIL) mission is providing unprecedentedly high‐resolution gravity data. The gravity signal in relation to topography decreases from 100 km to 30 km wavelength, equivalent to a uniform crustal density of 2450 kg/m 3 that is 100 kg/m 3 smaller than the density required at 100 km. To explain such frequency‐dependent behavior, we introduce rock compaction models under lithostatic pressure that yield radially stratified porosity (and thus density) and examine the depth extent of porosity. Our modeling and analysis support the assertion that the crustal density must vary from surface to deep crust by up to 500 kg/m 3 . We found that the surface density of megaregolith is around 2400 kg/m 3 with an initial porosity of 10–20%, and this porosity is eliminated at 10–20 km depth due to lithostatic overburden pressure. Our stratified density models provide improved fits to both GRAIL primary and extended mission data.