TL sensitivity of single chondrules from type 3 chondrites: Thermal metamorphism of chondrules in a nebular environment?

Chondrules are millimeter sized near spherical objects that comprise >50% of the volume of chondritic meteorites. Determinations of the initial Al/2726Al ratios from earlier studies of ferromagnesian chondrules in unequilibriated ordinary chondrites indicate that most chondrules formed between ∼1.5 and 2.5 Ma after the formation of calcium-aluminium rich inclusions (CAIs) in the early solar system. This paper investigates the thermoluminescence sensitivity of chondrules from unequilibriated ordinary chondrites to search for indications of thermal metamorphism in a pre-parent body. Our results suggest that a few chondrules in Semarkona and Bishunpur chondrites with higher levels of TL sensitivity may have experienced such thermal metamorphism in a pre-parent body environment.