The aim of this study is to attain a better understanding of the fate and preservation of organic matter through the high temperature processes associated with intrusions and atmospheric entry. Three high temperature regimes were investigated: Intrusions emplaced into organic-rich sediments with differing organic matter types; The STONE 6 atmospheric entry experiment using a sample of Devonian carbonaceous laminate; experimental pyrolysis of the Murchison carbonaceous chondrite.  A further study was performed on refining the experimental pyrolysis technique. For the intrusion studies, each case exhibited zones of petroleum generation towards the intrusion contacts, along with a significant increase in structural order.  Raman spectroscopy has been used to locate the position of an effective oil window next to one intrusion example.  The STONE 6 atmospheric entry experiment has returned carbon preserved in a disordered form alongside some evidence of interior protection.  The structural order of the organic matter present in the Murchison carbonaceous chondrite has increased significantly through both increasing temperature and duration.  An estimation of the size of meteorite that would be required to provide safe transit of organic materials is present at the end of this study with a detailed discussion on the complexities of interpreting the structural changes that are observed in disordered organic materials.