According to the results of a new study, soon after the creation of the solar system, Mars may have formed a primordial crust capable of hosting life. The research is based on an analysis of the rare and super-valuable Black Beauty meteorite, which was discovered in the Sahara Desert back in 2011.
Early in the history of our solar system, rocky planets such as Earth and Mars are thought to have been covered in global oceans of liquid magma. Eventually, these oceans are thought to have crystallized, or solidified, giving rise to relatively stable outer layers known as crusts.
For obvious reasons, the formation of a crust is a vital step towards making a planet a viable candidate for the emergence of life, yet the timelines upon which these geological processes took place are still poorly understood.
An international team of scientists has provided evidence as to when Mars' magma ocean may have crystallized, by cracking apart the Martian Black Beauty meteorite. Martian meteorites are extremely valuable hunks of material that are greatly prized by collectors, and also scientists hoping to use the ancient samples to shed light on some of the prevailing mysteries surrounding the evolution of the Red Planet.
The Black Beauty is an especially expensive specimen, with a single gram of the meteorite selling for approximately US$10,000 a pop. The scientists behind the new study were able to obtain an impressive 44 grams of the rare meteorite. Their goal was to analyze deposits of a mineral called zircon that were embedded within the Black Beauty.
Zircon is an incredibly tough mineral that is known to preserve information concerning the location in which it crystallized. As an added bonus, the mineral can also be dated incredibly accurately by observing isotopic decay within the material.
The zircon deposits in the Black Beauty were extremely small, and in order to get to them, the scientists were forced to crush 5 grams of the valuable meteor. Thankfully, their gamble paid off, and the scientists were able to analyze seven distinct zircons, one of which proved to be the oldest Martian zircon ever discovered.
It was found that the deposits contained a significant levels of the chemical element hafnium, which formed part of the earliest crust of Mars. By analyzing these tiny pieces of ancient Mars, the scientists were able to conclude that the Red Planet's surface-spanning ocean of magma had crystallized within 20 million years of the creation of the solar system, and that soon after, a solid crust had come to form. This primordial crust could have played host to oceans of water, presenting a theoretically habitable environment
The data supports an extremely rapid crystallization process. For comparison, a solid crust would not form on Earth for another 130 million years. The team estimates that Mars' early crust lasted for roughly 100 million years before being reworked, possibly by cataclysmic asteroid impacts. This cataclysm melted the Red Planet's surface, creating magma from which the Black Beauty's zircons, complete with samples of the primordial Martian crust, crystallized.
The study significantly expands the window in which life could have emerged on Mars, and, to paraphrase Jurassic Park's Dr. Ian Malcolm, the longer that Mars remained potentially habitable, the longer there was for life to, uh, find a way …
A paper detailing the findings has been published in the journal Nature.
