Research has continued on the response of organic matter in the crater target rocks to the impact event.
Our previous studies have shown that organic matter increases in thermal maturity (more heated) towards the crater centre, but that in most of the crater the heating was not so intense as to destroy fossil biomolecular evidence of life, or even extant life. This seasonÕs work has focussed on detailed sampling of fragments of the dolomite bedrock incorporated within the impact melt breccia. We want to investigate if these fragments retain some organic molecules despite their incorporation in a melt at over 600 ¼C (and possibly over 1000 ¼C). This will be done in two ways. Large (20 cm square and bigger) blocks will be sub-sampled to compare heating at the edge and progressively towards the centre, which may have been buffered from extreme heat. The alternative approach involves analyzing fragments of different sizes, to see if there is a minimum size in which organic molecules are preserved. All samples will be analysed by gas chromatography-mass spectrometry at the University of Aberdeen Organic Geochemistry Laboratory, to search for the critical molecules.
In support of our analyses of crater bedrock, we are characterizing the organic signatures of various types of modern biological material (cyanobacterial mat, moss, Arctic willow), so that contamination of the bedrock by these materials can be stripped out of the data.
Our overall goal is to help understand what bedrock samples in a crater of a given size on Mars could be sampled for determination of any biomolecular content.