The thermal alteration by pyrolysis of the organic component of small projectiles of mudrock during capture at hypervelocity

In a series of experiments the pyrolytic effects of the heating induced during the hypervelocity impact (HVI) of small projectiles of high TOC mudrock were observed. Impacts at these high speeds (km s(-1)) release sufficient energy to vaporise metal projectiles, and the temperatures created greatly exceed the pyrolysis temperatures typically employed during laboratory studies of the thermal alteration of sedimentary organic matter. Despite this the organic geochemical analyses of projectiles of Orcadian Laminite impacted into targets of sand and water at hypervelocities provides evidence that the structural backbone of biomarkers has remained intact and that only a comparatively low degree of thermal alteration (pre-oil window) has occurred. While further studies are necessary, it appears that the organic component of a projectile captured at hypervelocity will be a slightly thermally altered sample of its precursor. (C) 2008 Elsevier B.V. All rights reserved.