Silicates and Glass in Comet Wild 2 Samples: An Analytical Transmission Electron Microscope Study

Introduction: We received a total of nine Wild 2 samples from NASA JSC for our examination during the period of February to June, 2006 (Table 1). In this paper, we present the results of detailed mineralogical investigation of those samples using an analytical transmission electron microscope (TEM). The results reveal that the nine samples can be divided into three groups on the basis of their constituents: (1) crystalline silicate-rich (three samples), (2) Si-O glass-rich (four), and (3) indefinable (two) (Table 1). All three samples in group (1) were found at track termini in the aerogel capture cells, whereas the rest were found along tracks. This paper focuses on the results of the samples in groups (1) and (2). The two samples in group (3) contain a variety of unusual materials, some of which may be contaminants; their results will be shown elsewhere.