Abstract:

The GRV 024516 and GRV 024517 meteorite samples collected from Grove Montains,Antactica are ureilite and H5 ordinary chondrite,respectively.Based on the study of mineralogy-petrology we determined and calculated cosmic-ray exposure ages and gas retention ages of these two meteorites.The cosmic-ray exposure ages are 33.3Ma and 51.7Ma,respectively.The gas retention ages are 1936.8Ma and 3720 Ma,respectively.Ureilite contains diamond,graphite and amorphous C,which are the main carrier of noble gases and shows shock metamorphism effects,which induced 40Ar partial loss.The H5 chondrite indicates thermal metamorphism of parent body,and its gas retention age falls between 3220Ma and 4510Ma of the least shocked H5 chondrites.