Thermoluminescence analysis of micrometer fragments of primitive extraterrestrial materials

Extraterrestrial materials such as the matrix from unequilibrated ordinary chondrites (UOCs) and Antarctic micrometeorites (AMMs) represent some of the most primitive solar system materials and as such they retain a memory of early solar system formation processes. Fine scale isotopic analysis of these materials led to the discovery of presolar mineral assemblages which survived the formation of our solar system intact and have provided a new window into the chemical and thermal processes operating at the time.;There are many techniques which can determine the mineralogic, petrologic or compositional information about extraterrestrial materials. Few of these, however, can provide the insight into the history of a material that is possible with thermoluminescence (TL) analysis. Heretofore considered a "bulk sample" technique we have now extended its capability to include single micrometer particle analysis. In addition to the mineralogical information provided by TL analysis it is now possible to decipher the radiation and thermal history of primitive solar system materials on a scale never achieved before.;In each case we have seen uniform induced thermoluminescence peak temperatures and peak widths that are indicative of a simple mineralogy being responsible for the observed TL. However, when compared to a plot of peak temperatures vs. peak widths for Type 3 ordinary chondrites, where feldspar is known to be responsible for the TL, we see little or no correlation. Detailed analysis of these data suggests that forsterite, a mineral well known to be present in many astrophysical environments, is causing the luminescence seen in these materials.;Natural TL data has shown fine scale radiation and thermal heterogeneities present in all the materials analyzed to date which, when considering the close proximity of the samples to each other, is a surprising result. The data suggest that these materials contain highly localized radiation/thermal effects from galactic/solar cosmic ray exposure that is dependent on the location and quantity of specific target nuclides and/or atmospheric entry.