University of Tennessee geologist Larry Taylor, along with four other scientists, identified a new lunar material in a meteorite found in Oman.
Taylor, professor and director of the planetary geosciences department, said the new mineral is unlike anything found on Earth and explains weathering on the moon. The new mineral's identity was reported in the journal proceedings of the National Academy of Sciences.
Named for the scientist who 30 years ago predicted the space-weathering process that forms this mineral, Hapkeite is an iron-silicon compound formed by the constant bombardment of tiny meteorites into the moon's surface.
"The moon is a very hostile place," Taylor said. "It is constantly being struck by meteorites because it has no atmosphere to protect it like we have on Earth."
Most of the projectiles that hit the moon are so small they are not visible to the naked eye, Taylor said. The meteorites are traveling at speeds unknown on Earth, so their impact generates heat that melts soil particles, Taylor said.
Portions of the melted material vaporize and condense into elemental iron, a silica-rich gas and hapkeite, which has two atoms of iron and one of silicon. Taylor said hapkeite has a different origin and structure than iron-silicon materials that are sometimes created when lightning strikes Earth.
Unlike Earth, the moon has no wind, water or chemical process to which weathering can be attributed. The impacts of meteorites and micrometeorites cause the major space weathering on the moon, Taylor said.
"Bruce Hapke of The University of Pittsburgh said 30 years ago that the heat from micrometeorites was creating a vaporization, which was forming new minerals on the moon. It is fitting that we name the new mineral for Bruce," he said.
Taylor, who has worked with lunar samples since the Apollo astronauts first collected them 35 years ago, is now checking some of those lunar soil grains for hapkeite. The meteorite used for confirming the presence of hapkeite was found in 2000 in the Dhofar region of Oman. The deserts of the Middle East and polar ice caps are the best sources of meteorites because the charred rocks are easier to spot against light-colored sand or ice, he said.
Mahesh Anand, currently on a post-doctoral fellowship with the mineralogy department of London's Natural History Museum, worked with Taylor at UT as a post-doctoral fellow on the hapkeite project. Scientists from Russia's Vernadsky Institute of Geochemistry and the Geophysical Laboratory of the Carnegie Institution in Washington also participated.
Published: Tue Jul 13, 2004 | Modified: Sat Aug 06, 2005 06:12 p.m.