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All appendix tables for this article are available online at http://meteoritics.org.Abstract-Four parameters of low-field magnetic susceptibility (bulk value, frequency dependence, degree of anisotropy, and ellipsoid shape) have been determined for 321 stony meteorites from the National Collection of Canada. These parameters provide a basis for rapid, non-destructive, and accurate meteorite classification as each meteorite class tends to have a distinct range of values.Chondrites show a clear trend of increasing bulk susceptibility from LL to L to H to E within the 3.6 to 5.6 logχ (in 10 −9 m 3 /kg) range, reflecting increasing Fe-Ni metal and Fe-Ni sulfide content. Achondrite values range in logχ from 2.4 to 4.7 and primitive achondrites from 4.2 to 5.7. Frequency dependence is observed, using 19,000 Hz and 825 Hz, with variations in strength among meteorite classes and individual specimen dependence ranging from 1-25.6%. Degrees of anisotropy range from 1 to 53% with both oblate and prolate ellipsoids present. The aubrite class is marked by high degrees of anisotropy, low bulk magnetic susceptibility, and prolate fabric. Camel Donga is set apart from other eucrites, marked by higher bulk susceptibility, degree of anisotropy, and magnitude of oblate ellipsoid shape. The Shergotty, Nakhla, and Chassigny (SNC) meteorites show subclass distinction using frequency dependence and Chassigny is set apart with a relatively strong oblate fabric. The presence of both strong oblate and prolate fabrics among and within meteorite classes of chondritic and achondritic material points to a complex, multi-mechanism origin for anisotropy, more so than previously thought, and likely dominated by impact processes in the later stages of stony parent body formation.

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Abstract-Bulk density is an important intrinsic property of meteorites, but the necessary bulk volume measurement is difficult to do in a truly nondestructive way. Archimedean methods involving the displacement of a 40-100 lm beads ''fluid'' are commonly applied, but can encounter systematic errors. Herein, we report a visible light laser imaging technique for the nondestructive measurement of meteorite surface features, allowing for the subsequent assembly of 3-D volumetric models; the method is particularly applicable to small meteorite fragments and to fragile specimens. We have acquired laser image data for 24 fragments from 18 ordinary chondrites, carbonaceous chondrites, and achondrites, with masses ranging from 265.0 to 1.2 g. Laser imaging bulk density is consistent between sister fragments of meteorites down to sizes of about 0.5 cm 3 , an order of magnitude smaller than can be reliably measured with Archimedean beads techniques. Uncertainty is less than 2% for fragments >4 cm 3 , and typically between 2 and 4% for small fragments <4 cm 3 . For 10 fragments, 3-D laser imaging volumes are on average 1.3% smaller than those obtained with Archimedean beads. In a wider comparison using 21 meteorite fragments, 3-D laser imaging bulk densities are on average 2.14 ± 2.36% greater than the corresponding Archimedean method literature values for these meteorites. Difficulties in the procedure of 3-D image alignment may lead to a slight overestimation of meteorite bulk density, and so laser imaging-based bulk densities are maximum estimates that can be viewed as being complementary to the minimum bulk density estimates obtained using Archimedean beads methods.

[1] The fragile and unique nature of meteoritic material requires a method of density measurement that is accurate yet nondestructive. This is difficult to achieve using conventional methods. In this study, the bulk density of eleven meteorite fragments which vary in shape, size, surface roughness, porosity, and reflectance has been determined using three-dimensional (3-D) laser imaging. An auto-synchronized laser camera raster scanned the surface features of each meteorite without contact and to a high degree of precision. Visualization software was used to align several scans into a closed model and to compute its volume. The mass having been predetermined, the density was then easily computed. Three-dimensional laser imaging is the least invasive method of density measurement currently in use. The precision of the approach is less than 1%. The densities determined using 3-D laser imaging compare very well with previously published values, based on a variety of different measurement techniques. The average difference is 3.4% and can be attributed to the presence of heterogeneities and to the limited amount of comparative data available. For nine out of the eleven samples studied, the densities determined using 3-D laser imaging are higher than previously published results. Friction between fluid and container, and bead compaction might have led to an overestimation of the volume measured using Archimedean methods. In addition to volume measurements, 3-D images of rock samples can yield detailed information on surface properties from a distance. The technique could be used for semiautonomous planetary geological exploration.