Aliphatic Aldehydes in the Earth’s Crust—Remains of Prebiotic Chemistry?

Abstract

The origin of life is a mystery that has not yet been solved in the natural sciences. Some promising interpretative approaches are related to hydrothermal activities. Hydrothermal environments contain all necessary elements for the development of precursor molecules. There are surfaces with possible catalytic activity, and wide ranges of pressure and temperature conditions. The chemical composition of hydrothermal fluids together with periodically fluctuating physical conditions should open up multiple pathways towards prebiotic molecules. In 2017, we detected potentially prebiotic organic substances, including a homologous series of aldehydes in Archean quartz crystals from Western Australia, more than 3 billion years old. In order to approach the question of whether the transformation of inorganic into organic substances is an ongoing process, we investigated a drill core from the geologically young Wehr caldera in Germany at a depth of 1000 m. Here, we show the existence of a similar homologous series of aldehydes (C8 to C16) in the fluid inclusions of the drill core calcites, a finding that supports the thesis that hydrothermal environments could possibly be the material source for the origin of life.

Storage of Biochemical Information as the Start of Life: A Hypothetical Model for the Development of the First Cell

“…Information about the typical chemistry of the fluids from the fault zones can be determined by analysing the fluid inclusions in hydrothermally formed fissure minerals. These minerals were previously found both in archaic hydrothermal quartz minerals of Western Australia and in the most recent fissure calcites in the vicinity of sub-recent volcanoes in the Eifel [5,28].…”

“…Through Fischer/Tropsch-like synthesis and other processes (e.g., the Haber-Bosch process), organic molecules, which are a prerequisite for the development of life, could be formed from abiotic starting materials. Starting substances for lipids, such as aldehydes, were found in the fluid inclusions of hydrothermal archaic quartz minerals and in recent hydrothermal calcites [5,28]. Hennet et al (1992) showed that under simulated hydrothermal conditions (150 °C, 10 Atm, pH 7) with various mineral catalysts, amino acids could be formed from the starting compounds of the fluids (formaldehyde, ammonia, cyanide) [29].…”