Mineral grains from three depths within the Luna 24 drill core (
ca
. 90, 125 and 196 cm) have been examined for solar-flare tracks. Large proportions (55-100%) of grains from all three levels are found to be track-rich (with central track densities p
e
> 10
8
cm
-2
), and a substantial fraction (
ca
. 25-50%) of all grains display trackdensity gradients. These observations indicate that most of the mineral grains have been cycled through the top
ca
. 1 mm of the lunar surface at some time in their history. Some degree of submaturity is observed towards the bottom of the core. The most likely depositional model envisages rapid infall of highly irradiated material into a less mature local component with rather little subsequent reworking. Thermoluminescence (t.l.) studies indicate a lower natural radiation dose in samples from the 196 cm level compared with those from the two upper levels. This can result either from random variations in the local internal radioactivity or from mixing properties of the pre-irradiated material over time scales of less than
ca
. 100 ka. Radiation sensitization of samples suggests a possible use of t.l. sensitivity for the interpretation of lunar radiation history.
Smoking and radiation history are significantly associated with osteosynthesis-associated delayed complications in free fibula reconstruction of mandible — a retrospective study
