Scientists with Caltech have reported the discovery of a new kind of mineral called “panguite” in the fragmentary remains of a meteorite that fell over Mexico in 1969. The Allende meteorite fell as a “fireball” meteorite over forty years ago, dropping debris over the state of Chihuahua. In the time since, scientists have gathered the meteor’s remains and subjected them to intense analysis.
Scientist Chi Ma of Caltech’s Geological and Planetary Sciences Division’s Analytical Facility, and also coauthor of the new paper, notes the significance of the finding. “Panguite is an especially exciting discovery since it is not only a new mineral, but also a material previously unknown to science.” The authors note that the mineral is not known to have ever been made synthetically. Since 2007, Ma’s team at Caltech has been conducting a focused nanomineralogy investigation of the Allende meteorite. Nanomineralogy examines minerals and their features at the smallest scales, making use of the most advanced of microscopic and crystallographic technologies.
The Allende meteorite is the largest of the carbonaceous chondrite meteorites ever found on Earth. Whereas much of the solar system’s matter has been changed through successive cycles of being included in planets or other larger objects, or otherwise modified through time, the chondrites are thought to have remained relatively stable since their first formation approximately 4.5 billion years ago. Such meteorites represent the earliest conglomerations of matter in the solar system, and have not been altered through heating or inclusion in a larger object.
Examining a fragment with a scanning electron microscope, the new mineral was found in a small solid particle called a “refractory inclusion” embedded in the meteorite. These particles are believed to be remnants of the first formation of the solar system, and are also chemically stable across a wide variety of conditions, and as such their chemistry and contents can potentially reveal clues about the solar system’s earliest history. That means that the refractory inclusions could only have formed in the extreme conditions of the early solar system’s formation, and have remained stable since.
Panguite is the ninth new mineral found in the Allende meteorite. George Rossman, a Caltech scientist and coauthor of the paper announcing panguite’s discovery, says, “The intensive studies of objects in this meteorite have had a tremendous influence on current thinking about processes, timing, and chemistry in the primitive solar nebula and small planetary bodies.” Ma adds that such studies are more important than just cataloging new kinds of substances. “Such investigations are essential to understand the origins of our solar system,” he says.
The researchers named the new mineral, which is a type of titanium oxide, after the Chinese giant Pan Gu, who according to myth separated yin from yang to create the earth and the sky. They note that this allusion is a reference to the mineral’s identity as a remnant of the earliest formation of solid material in the solar system. The mineral and its new name have been recognized by the International Mineralogical Association’s Commission on New Minerals, Nomenclature and Classification, the official body for recognizing such discoveries.
The study was funded through the National Science Foundation, the U. S. Department of Energy, and NASA’s Office of Space Science. The announcement is set to be published in the July issue of American Mineralogist.
