University of wyoming dating
A University of Wyoming research professor has helped solve the question of how old Mars meteorites are and when volcanism actually occurred on the red planet.Kevin Chamberlain, a research professor in UW’s Department of Geology and Geophysics, used newly developed mineral-dating techniques he created to determine the age of volcanism on Mars at 200 million years ago, as well as the timing of a large-impact event 22 million years ago that launched rocks off the surface of Mars. Chamberlain is one of seven co-writers of a research paper, titled “Solving the Martian Meteorite Age Conundrum Using Micro-Baddeleyite and ‘Launch-Generated Zircon’,” that was published in today’s issue of Nature, an international weekly journal of science that publishes peer-reviewed research in all fields of science and technology.The dating technique required the use of a specialized instrument called a secondary ionization mass spectrometer or SIMS, of which only three exist in North America, Chamberlain says.The instrument analyzes a mineral sample by excavating microscopic pits (about 1 micron deep by 20 microns in diameter) in the rock sample and analyzing the isotopic compositions of the excavated material.All 18 were found within a 20-millimeter square (roughly three-fourths of an inch) region of a polished surface of the meteorite.Both minerals are major reservoirs for uranium in meteorites.Using the mass spectrometer, Chamberlain measured the ratio of lead to uranium, which allowed him to calculate the age of the meteorite grains.
“The combination of techniques allowed us to determine the magmatic age of the lava on Mars as well as the time that the sample was launched into space by a bolide impact,” Chamberlain says.
“Our results also solved an ongoing debate about the age of magmatism that most Martian meteorites appear to have sampled.” New frontiers Chamberlain developed the new dating technique at UW with Norbert Swoboda-Colberg, a lab technician in the UW Department of Geology and Geophysics, and Susan Swapp, a senior research scientist, also in geology and geophysics.