[meteorite-list] Ultraviolet Space Rocks?
bernd.pauli at paulinet.de
bernd.pauli at paulinet.de
Sat Oct 2 08:19:58 EDT 2010
Hello All,
Here are some details from an abstract,
Cheers,
Bernd
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D.W.G. Sears, P.H. Benoit, and D.G. Akridge (1999) Thermoluminescence
and The Thermal History Of Meteorites (MAPS 34-4, 1999, A105, excerpts):
- the TL sensitivity of unequilibrated ordinary chondrites correlates
with petrographic type and thus metamorphic history
- the TL sensitivity of type 3 chondrites correlates with a variety of indicators
of metamorphic alteration such as mineral heterogeneity, volatile contents, and
abundance of presolar grains
- TL sensitivity is the basis of the widely used subdivision
of type 3 ordinary chondrites into types 3.0-3.9
- cathodoluminescence (CL) studies indicate that the TL sensitivity
increases during metamorphism as glass crystallizes to feldspar
- the temperature and width of the induced TL peak are also related to thermal
history. Thus peak temperature and width can be used for palaeothermometry.
Some conclusions based on such measurements:
- the CV and CO chondrites spent a longer time at lower temperatures than UOC
- the TL sensitivity of the comminuted matrix of regolith breccias is lower than
that of the clasts due to the destruction of crystalline feldspar. Thus the matrix-
to-clast TL sensitivity ratio provides a measure of regolith maturity (similar trend
observed in lunar breccias and lunar soils)
- the HED meteorites, especially the eucrites, can be subdivided into petrographic
types 1-6 using TL sensitivity and the types agree with those based on mineralogy.
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