“Our work began with an eye toward understanding the hydrocarbons found in Martian meteorites, but we soon realized that there are plenty of gas compositions from Earth’s volcanoes, and we thought we should study the full range of possibilities. So, with this paper we analyzed the hard physical evidence from the Earth, and, from that, we think we can extrapolate to Mars.
“The calculations prove what can happen thermodynamically, but not necessarily what will happen. Developing them is an important first step in understanding this process. For the first time, we now have a quantified temperature zone in which hydrocarbons can form, and a framework to understand what conditions lead to hydrocarbon formation from volcanic gas.
There have been a number of experiments in this area over the years, but not a framework to better understand the process. Misha’s (Zolotov’s) calculations predict what kinds of chemical clues one should see based on the organic compounds that are present.”
Approachable Processes
Zolotov gathered data from volcanoes ranging from Mt. St. Helen’s and Iceland’s Surtsey to Sicily’s Mount Aetna and Hawaii’s Kilauea. All of the volcanoes arose from different geological settings and produced initial gas temperatures of varying ranges.
“The calculations show that there is a potential for hydrocarbons to form during the cooling process, and that this condition also is promising for amino acids to develop,” Zolotov says. “The process is not very efficient today. For instance, at Kilauea, the hydrogen and carbon monoxide amounts of the gases are no more than 2 percent. But it still is a steady source for hydrocarbons to form.”
As for the origins of life — on Earth, at least — there are two basic competing views: one suggests that life was brought here by comet or meteorite impacts or interplanetary dust; the other that life was generated here, either at the ocean floor, through a lightning spark that touched off an atmosphere that produced organic compounds in watery environments, or in volcanic gases. All scenarios involve organic compounds.
“Unlike spark discharge scenarios, the processes we are pursuing to study the origins of life, here, or on Mars, are normal, daily geological processes. The volcanic gas scenario is one of the most approachable,” says Shock. “The evidence is readily accessible, and we know we can extrapolate from evidence here to Mars and other bodies without much ambiguity.”
