One of the biggest questions in science is the process of origin of life on earth. Hypothetically, prebiotic chemistry and the formation of protocells may have evolved in the hydrothermal environment of tectonic fault zones in the upper continental crust [Orig Life Evol Biosph. 2012;42: 47–54], an environment where sensitive molecules are well protected against degradation induced e.g. by UV radiation. The composition of fluid inclusions in minerals such as quartz which have grown in this environment during the Archean period might provide important information about the first organic molecules formed by hydrothermal synthesis.
In fluid inclusions of Archean quartz minerals from Western Australia we found a variety of organic compounds such as alkanes, halocarbons, alcohols and aldehydes which unambiguously show that simple and even more complex prebiotic organic molecules have been formed by hydrothermal processes [PLoS ONE 12(6): e0177570]. Stable-isotope analysis confirms that the methane found in the inclusions has most likely been formed from abiotic sources by hydrothermal chemistry. Obviously, the liquid phase in the continental Archean crust provided an interesting choice of functional organic molecules. We conclude that these organic substances could have made an important contribution to prebiotic chemistry which might eventually have led to the formation of the first living cell.
To support this thesis, we have now taken part in a drilling in the Wehrer Kessel in the Vulkaneifel, Germany. This is a region in Germany, that is defined to a large extent by its volcanic geological history. Characteristic of this volcanic field are e.g. volcanic tuffs, lava streams and volcanic craters like the Laacher See. The Volcanic Eifel is still volcanically active today. We had taken a 18 m long drill core (between 950 and 968 m depth). In this region, the transition from CO2 supercritical to CO2 subcritical should have taken place. According to our theory, in this transition substances that have formed at depth must have precipitated due to the loss of solubility at the transition to CO2 in the subcritical temperature range. We now hope to be able to detect substances similar to those found in the quartz samples from Western Australia.