Publikationsdatum:
2016-10-16
Beschreibung:
Planetary collisions in the solar system typically induce melting and vaporization of the impactor and a certain volume of the target. To study the dynamics of quasi-instantaneous melting and subsequent quenching under post-shock P–T conditions of impact melting, we used continuous-wave laser irradiation to melt and vaporize sandstone, iron meteorite, and basalt. Using high-speed imaging, temperature measurements, and petrologic investigations of the irradiation targets, we show that laser-generated melts exhibit typical characteristics of impact melts (particularly ballistic ejecta). We then calculate the entropy gains of the laser-generated melts and compare them with the entropy gains associated with the thermodynamic states produced in hypervelocity impacts at various velocities. In conclusion, our experiments extend currently attainable post-shock temperatures in impact experiments to ranges commensurate with impacts in the velocity range of 4–20 km s –1 and allow to study timescales and magnitudes of petrogenetic processes in impact melts.
Print ISSN:
0094-8276
Digitale ISSN:
1944-8007
Thema:
Geologie und Paläontologie
,
Physik