2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 3
Presentation Time: 8:30 AM

Ultrafast Phase Mapping of Thin-Sections from An Apollo 16 Drive Tube − A New Visualisation of Lunar Regolith


BOTHA, Pieter W.S.K.1, BUTCHER, Alan R.2, HORSCH, Hanna3, RICKMAN, Doug4, WENTWORTH, Susan J.5, SCHRADER, Christian M.6, STOESER, Doug7, BENEDICTUS, Aukje3, GOTTLIEB, Paul3 and MCKAY, David8, (1)ARMC, Intellection Corporation, 10955 Westmoor Drive, Suite 400, Westminster, CO 80021, (2)FEI Australia, 27 Mayneview St, Milton, Queensland, 4064, Australia, (3)Intellection Pty Ltd, 27 Mayneview St, Milton, Queensland, 4064, Australia, (4)Marshall Space Flight Center, Code VP61, NASA, 320 Sparkman Drive, Huntsville, AL 35802, (5)ERC/ESC Group, JE23, NASA Johnson Space Center, 2101 NASA Parkway, Houston, TX 77058, (6)BAE Systems-MSFC, 320 Sparkman Drive, Huntsville, AL 35802, (7)Central Region Mineral Resources Team, USGS, Mail Stop 973 Box 25046 DFC, Denver, CO 80225, (8)Astromaterials Group, NASA Johnson Space Ctr, Mail code SN, Houston, TX 77058, Pieter.Botha@intellectioncorp.com

Polished thin-sections of samples extracted from Apollo drive tubes provide unique insights into the structure of the Moon's regolith at various landing sites. In particular, they allow the mineralogy and texture of the regolith to be studied as a function of depth. Much has been written about such thin-sections based on optical, SEM and EPMA studies, in terms of their essential petrographic features, but there has been little attempt to quantify these aspects from a spatial perspective.

In this study, we report the findings of experimental analysis of two thin-sections (64002,6019, depth range 5.0 – 8.0 cm & 64001,6031, depth range 50.0 – 53.1 cm), from a single Apollo 16 drive tube using QEMSCAN®. A key feature of the method is phase identification by ultrafast energy dispersive x-ray mapping on a pixel-by-pixel basis. By selecting pixel resolutions ranging from 1 – 5 microns, typically 8,500,000 individual measurement points can be collected on a thin-section.

The results we present include false colour digital images of both thin-sections. From these images, information such as phase proportions (major, minor and trace phases), particle textures, packing densities, and particle geometries, has been quantified. Parameters such as porosity and average phase density, which are of geomechanical interest, can also be calculated automatically.

This study is part of an on-going investigation into spatial variation of lunar regolith and NASA's ISRU Lunar Simulant Development Project.