^1,2Jon M. Friedrich,^2,3,4Michael K. Weisberg,¹Lucille C. Malecek,²C. E. Nehru
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13751]
¹Department of Chemistry, Fordham University, Bronx, New York, 10458 USA
²Department of Earth and Planetary Sciences, American Museum of Natural History, New York, New York, 10024 USA
³Department of Physical Sciences, Kingsborough Community College, Brooklyn, New York, 11235 USA
⁴Graduate Center of the City University of New York, New York, New York, 10016 USA
Publsihed by arrangement with John Wiley & Sons

We use X-ray microtomography (µCT) and digital data extraction techniques for the three-dimensional (3-D) petrographic investigation of the Tucson meteorite. Our results show that the silicate-free metal regions in Tucson exist as discrete objects surrounded by a continuous silicate-containing metal “matrix.” Volumetric measurements of the silicate-free metal regions in Tucson demonstrate that they are akin to the sizes of metallic nodules found in CBa chondrites. Silicate-free metal regions have bladed or prolate shapes. Nonmetallic minerals in Tucson are predominately equant or prolate in shape. Nonmetallic mineral grains and silicate-free metal regions in Tucson share a common orientation and are part of a petrofabric composed of a lineation. Any foliation in Tucson is weakly developed. We interpret the petrofabric as being the result of a single event on the Tucson parent body, during which Tucson experienced shearing forces. Our 3-D petrographic investigation supports the idea that Tucson is an unusual member of the CR chondrite clan.