Geochemical context for hydrothermal organic molecules in terrestrial Mars analog samples.Geochemical context for the interpretation of hydrothermal organics in planetary environments.

Understanding the processes that govern preservation and transport of organic molecules in modern and ancient hydrothermal environments on Earth are critical to the search for life elsewhere. An improved understanding of these settings and organic molecules is an objective of the planned Mars Sample Return mission, and is relevant in the search for life on icy moons with subsurface oceans, such as Enceladus. However, assessing the syngeneity and indigeneity of organic matter in hydrothermal environments on Earth can be challenging. Organic matter in these environments is frequently a complex mixture of molecules that have been variously matured and altered by diverse mechanisms in situ, in the subsurface and surrounding environments, and combining in situ and transported molecules. Research into hydrothermal environments on Earth mostly consists of studies of submarine (seafloor) vents or studies into subaerial (land-based) hot springs. Whilst the sources and fates of organics in marine hydrothermal environments are different than the sources and fates of organics in subaerial hydrothermal environments, many of the processes that govern the transport and alteration of organic matter are the same. To aid in understanding the origin of any organics found in samples from another world, we must critically evaluate the processes that alter organics as a whole in these environments.