Nondestructive determination of the physical properties of Antarctic meteorites: Importance for the meteorite—parent body connection

Abstract

Photogrammetry is a low‐cost, nondestructive approach for producing 3‐D models of meteorites for the purpose of determining sample bulk density. Coupled with the use of a nondestructive magnetic susceptibility/electrical conductivity field probe, we present measurements for the interrogation of several physical properties, on a set of Antarctic meteorites. Photogrammetry is an effective technique over a range of sample sizes, with meteorite bulk density results that are closely comparable with literature values, determined using Archimedean glass bead or laser scanning techniques. The technique is completely noncontaminating and suitable for the analysis of rare or fragile samples, although there are limitations for analyzing reflective samples. It is also flexible, and, with variations in equipment setup, may be appropriate for samples of a wide range of sizes. X‐ray computed tomography analyses of the same meteorite samples yielded slightly different bulk density results, predominantly for samples below 10 g, although the reason for this is unclear. Such analyses are expensive and potentially damaging to certain features of the sample (e.g., organic compounds), but may be useful in expanding the measurements to accommodate an understanding of internal voids within the sample, lending itself to measurement of grain density. Measurements of bulk density are valuable for comparisons with estimates of the bulk densities of asteroids that are suggested as meteorite parent bodies.

Advanced microstructural and compositional analysis of a lunar agglutinate from the Apollo 11 mission

“…XCT is a virtually nondestructive characterization technique that helps us acquire detailed microstructural information, with spatial resolutions reaching micrometer and nanometer scales (Harvey et al., 2023). In a typical lab‐scale XCT setup, x‐rays generated through an x‐ray tube source are made to pass through the sample, and the transmitted x‐ray photons are captured using a detector.…”

Overview of the Lost Meteorites of Antarctica field campaigns

“…he frozen samples were received for preliminary examination and curation at the University of Manchester, United Kingdom (MacArthur, Joy, Harvey, Jones, Evatt, Almeida, Malley, Greenwood, Findlay, & King, 2022) and are in the process of being classified (Gattacceca et al, 2022(Gattacceca et al, , 2023Metoritical Bulletin, 2023). The sample curation and initial analysis are discussed in Joy et al (2021), MacArthur, Joy, Harvey, Jones, Evatt, Almeida, Malley, Greenwood, Findlay, andKing (2022) and MacArthur, and Harvey et al (2023). A summary of the meteorite types and statistics will be discussed in depth in future papers.…”

Antarctic meteorites threatened by climate warming

“…(1) Field observations: entrapped meteorites have been found covered by superimposed (refrozen) ice after the meteorite sank into the ice (Fig. 1) [14][15][16] . (2) Data on meteorite retrieval locations 9,17 indicate that almost no meteorites (<1% of all finds) are found in locations where surface temperatures of the ice are higher than −9 °C even very rarely (this near-maximum value of the surface temperature is…”

“…c, Meteorite MIL 07710 (147 g) fully enclosed in ice, collected as part of the Antarctic Search for Meteorites (ANSMET) programme (the number in the photo is used for documentation in the field). A column of clear, bubble-free ice above the meteorite was observed during the field mission (transparent on photograph), indicating that the meteorite sunk through melting underlying ice that refroze as superimposed ice above the sample16 . Credit: b, Katherine Joy, Lost Meteorites of Antarctica Project10,24 ; c, Ralph Harvey, ANSMET programme.…”