Geography and Geology
Chondrules are spherical grains made of silicates and metal that represent some of the oldest materials our solar system. Acfer-139 (CR) is a carbonaceous chondrite with large multilayered chondrules. The multilayered chondrules are composed of a silicate core surrounded by alternating layers of silicates and metals. Serial sectioning was used to analyze the sample in three dimensions. EMPA and LA-ICP-MS were used to create elemental maps of Acfer-139 (CR2) and determine the geochemistry of different layers in each thick section cut. XRCMT was used to construct a 3-D model of a large multilayered chondrule named Ch-1 with concentric layers of silicate and metal. A core to rim analysis of Ch-1 revealed increasing silica existing as olivine in the core and pyroxene at the edge. An increase in more volatile elements occurred from core to rim as well as a decrease in refractory elements. While the formation of layered chondrules is still being examined, core to rim analyses of Ch-1 support a formation consisting of silicate and metal layers being accreted onto the forsteritic core in a cooling protoplanetary disc.
Advisor(s) or Committee Chair
Dr. Andrew Wulff
Downen, Matt, "The Formation History Of Layered Chondrules In Acfer-139 (CR2)" (2011). Honors College Capstone Experience/Thesis Projects. Paper 334.