Characteristics in naturally and experimentally shocked chondrites: A clueto P-T conditions of impacted asteroids

The aim of this study is to compare the experimentally shock-induced featur es with those in naturally shocked chondrites and to test the feasibility o f experimentally calibrating naturally induced features in shocked H- and L -chondrites. Samples of the Jilin chondrite (H5) were experimentally shock- loaded at the following peak pressures: 12, 27, 39, 53, 78, 83, 93 and 133 GPa respectively. Chondritic melts were first obtained at P>78 GPa and more than 60% melting was achieved at P similar to 133 GPa. No high-pressure ph ases were observed in any of the shocked samples, neither in the deformed n or in the molten regions, Textural relations and mineral assemblages of the shocked samples are comparable to those encountered in the heavily shocked H-chondrite Yanzhuang but differ considerably from those found in heavily shocked L6 chondrites. Shock melt veins in L6 chondrites contain high-press ure polymorphs of olivine and pyroxene and high pressure liquidus phases. S caling from shock experiments on millimeter-sized samples to natural shock features on kilometer-sized asteroids poses considerable problems in quanti fying the P-T conditions during natural shock events on asteroids.