Understanding the Volcanic History of Mars
Studying volcanoes that are millions of miles away is a huge challenge, with limited options. Enter meteorites.
“The only volcanic samples from Mars we can study directly are meteorites,” said Tom Lapen, professor of geology in the College of Natural Sciences and Mathematics. “The only other opportunity to study Martian rocks comes directly from rovers, but analysis is limited by the technology and conditions in place.”
The Tissint Meteorite: An Observed Fall
In 2011, a meteorite fell in Morocco, the fragments scattering out over a distance, in what scientists call a ‘strewn field.’ The fragments, weighing about seven kilograms in total, or approximately the weight of a bowling ball, were quickly collected. These fragments, collectively called the Tissint meteorite, are Martian in origin, and can offer insights into volcanic activity on the Red Planet.
Lapen is the recipient of a three-year, $349,520 grant from the NASA Solar System Workings program, which will fund the ongoing analysis of Martian meteorites, including the Tissint. Other UH researchers involved in this research include Minako Righter, a researcher and lab supervisor in the Department of Earth and Atmospheric Sciences, and Stephanie Suarez, a master’s student in geology. Outside collaborators include Anthony Irving at the University of Washington and Brian Beard, a senior scientist in the Department of Geoscience at the University of Wisconsin at Madison.
“Analyzing these samples will give us a better understanding of the history of Mars,” Righter said.
The Tissint Meteorite: Ejected From Mars 1.1 Million Years Ago
The shield volcanoes and lava plains on Mars were formed from lava flowing out over long distances, similar to the formation of the Hawaiian Islands. This created layers of crystallized lava of different ages.
The Tissint meteorite is one of a group of meteorites that were ejected from Mars 1.1 million years ago, when something slammed into the planet. The impact carved out a crater and ejected a cross section of rocks out into space, some of which later fell to Earth.
Eleven of these meteorites have been found to date, all of which have a similar composition and ejection time, indicating they are most likely from the same spot on Mars. These 11 meteorites range in age from 170 million years to 2.4 billion years. Based on the range of ages, the impact was enough to carve out a significant cross section of lava layers.
“Even if we were somehow transported to Mars, we’d still have to drill down to get to the rock layers excavated by these craters,” Lapen said. “This is an unprecedented opportunity to study the volcanic history of Mars.”
Different Ages within the Same Meteorite
Preliminary analysis of the Tissint meteorite, which includes samples from different fragments recovered, shows a complex story, with different ages. In order to gain a more comprehensive understanding, Suarez will perform detailed analysis on multiple samples from the Tissint meteorite.
“We have conflicting ages for the Tissint meteorite,” Suarez said. “Our hypothesis is that the Tissint meteorite strewn field is composed of multiple lava layers of different ages.”
- Rachel Fairbank, College of Natural Sciences and Mathematics