A compositional study of the lunar global megaregolith using clementine orbiter data

• Main Author: Jackson, Noel William
• Format: Doctoral or Postdoctoral Thesis
• Language: unknown
• Published: 2005
• Subjects: lunar global megaregolith; clementine orbiter; basin impact ejecta model; south pole aitken basin; Aitken; South Pole; South pole
• Online Access: https://research.usq.edu.au/item/9xxxz/a-compositional-study-of-the-lunar-global-megaregolith-using-clementine-orbiter-data; https://research.usq.edu.au/download/a1ef00bdf866c2878b2a701d564b802afde8d390739417350e2560146b98c6fb/7991743/Jackson_2005_whole.pdf

This thesis presents new information about the global megaregolith of the Moon, using 2059 craters (5 to 50 km diameter) as natural probes. Iron (FeO) and titanium (TiO2) concentrations were obtained from crater ejecta blanket data over an area between 600 North to 600 South latitude derived from the 1994 Clementine mission. The average iron and titanium weight percentages for lunar crater ejecta were calculated using the US Geological Survey's ISIS software, and used to determine the variation with depth of iron (FeO) and titanium (TiO2) in the highlands, mare areas and the South Pole Aitken basin. In addition, megaregolith compositional Iron (FeO) and Titanium (TiO2) Maps and compositional Province Maps were generated, and studied in detail. The Lunar Megaregolith Iron Province Map divides the Highland areas into 2 distinct provinces of low-iron Highland I (0-3.7 FeO weight percentage) and low-medium level iron Highland II (3.8-6.4%), and the Mare and South Pole Aitken Basin each into 3 distinct provinces (6.5-9.7%, 9.8-13.6%, and 13.7-18.3%). Similarly, a Titanium Megaregolith Province Map divides the Moon globally into 5 provinces based on weight percentages of TiO2. A new finding is the Highland II Province of elevated iron concentration which surrounds basins. These elevated iron levels may be explained in terms of an 'Intrusion Model'. In this model, basin formation fractures the surrounding anorthositic bedrock, and the middle level anorthositic crust allows mafic (basaltic?) magma to intrude. This intrusion into the megaregolith is in the form of sills and dykes from deep mafic sources but generally does not intrude into the surface regolith. In some places however, the mafic (basaltic?) lava may have extruded onto the surface, such as near Crater 846 (15.6N 92.2W). The megaregolith, which consists of large volume breccia, would have voids and vacancies in this structure into which mafic or basaltic material could intrude. 'Islands' of Highland I Province material surrounded by Highland II Province ...