Chemical and physical studies of type 3 chondrites. I - Metamorphism related studies of Antarctic and other type 3 ordinary chondrites

• Main Authors: Sears, D. W., Grossman, J. N., Melcher, C. L.
• Format: Other/Unknown Material
• Language: unknown
• Published: 1982
• Subjects: 91; Antarctic; Antarc*
• Online Access: http://ntrs.nasa.gov/search.jsp?R=19830040113

New thermoluminescence (TL) sensitivity measurements on 17 finds and one fall are presented, and petrologic assignments are made on the basis of TL sensitivity and silicate heterogeneity. The correlation that exists between TL sensitivity and glow curve shape is discussed, with the difference in the glow curve shapes of meteorite types 3.4 and less and type 3.5 and greater being tentatively attributed to an order-disorder transition in plagioclase, the TL phosphor. A correlation between TL sensitivity and heteogeneity of the silicate composition is found, but it tends to break down in the most heterogeneous meteorites. For Antarctic meteorites, the TL data show a much more restricted range in TL sensitivity than in silicate heterogeneity. The Quinyambie meteorite is the only one not consistent with the observed trend. Several explanations are offered, none of them totally satisfactory.