Panguite, (Ti^(4+),Sc,Al,Mg,Zr,Ca)_(1.8)O_3, a new ultra-refractory titania mineral from the Allende meteorite: Synchrotron micro-diffraction and EBSD
Abstract
Panguite (IMA 2010-057), (Ti^(4+),Sc,Al,Mg,Zr,Ca)_(1.8)O_3, is a new titania, occurring as fine-grained crystals with Ti-rich davisite in an ultra-refractory inclusion within an amoeboid olivine inclusion from the Allende CV3 carbonaceous chondrite. The phase was characterized by SEM, EBSD, synchrotron micro-diffraction, micro-Raman spectroscopy, and EPMA. The mean chemical composition of the type panguite is (wt%) TiO_2 47.97, ZrO_2 14.61, Sc_2O_3 10.67, Al_2O_3 7.58, MgO 5.54, Y_2O_3 5.38, CaO 3.34, SiO_2 1.89, FeO 1.81, V2O_3 0.95, Cr_2O_3 0.54, HfO_2 0.28, sum 100.56 with a corresponding empirical formula calculated on the basis of 3 O atoms of [(Ti_(0.79)Zr_(0.16)Si_(0.04))^(4+)>_(Σ0.99)(Sc_(0.20)Al_(0.20)Y_(0.06)V_(0.02)Cr_(0.01))^(3+)_(Σ0.49) (Mg_(0.18)Ca_(0.08)Fe_(0.03))^(2+)_(Σ0.29)]_(Σ1.77)O_3. Synchrotron micro-Laue diffraction (i.e., an energy scan by a high-flux X‑ray monochromatic beam and white beam diffraction) on one type domain at sub-micrometer resolution revealed that panguite is an orthorhombic mineral in space group Pbca. The structure is a subgroup of the Ia3 bixbyite-type. The cell parameters are a = 9.781(1), b = 9.778(2), and c = 9.815(1) Å, yielding V = 938.7(1) Å^3, Z = 16, and a calculated density of 3.746 g/cm^3. Panguite is not only a new mineral, but also a new titania material, likely formed by condensation. It is one of the oldest minerals in the solar system.
Additional Information
© 2012 Mineralogical Society of America. Manuscript received October 10, 2011. Manuscript accepted February 22, 2012. Manuscript handled by Fernando Colomombo. SEM, EBSD, and EPMA analyses were carried out at the Caltech GPS Division Analytical Facility, which is supported, in part, by NSF Grants EAR-0318518 and DMR-0080065. Synchrotron micro-diffraction was carried out at the 34ID-E beamline of the Advanced Photon Source. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract no. DE-AC02-06CH11357. This research was also supported by NNSA Cooperative Agreement DE-FC88-01NV14049, NASA OSS Grant NNX09AG40G, and NSF Grant EAR-0947956. We thank Aicheng Zhang for bringing the CH chondrite SaU 290 to Caltech for EBSD and EPMA study. We thank Irina Galuskina, Vladimir Bermanec, and Fernando Colombo for their helpful reviews.Additional details
- Alternative title
- Panguite, (Ti4+,Sc,Al,Mg,Zr,Ca)1.8O3, a new ultra-refractory titania mineral from the Allende meteorite: Synchrotron micro-diffraction and EBSD
- Eprint ID
- 32103
- Resolver ID
- CaltechAUTHORS:20120626-134127014
- EAR-0318518
- NSF
- DMR-0080065
- NSF
- DE-AC02-06CH11357
- Department of Energy (DOE)
- DE-FC88-01NV14049
- NNSA Cooperative Agreement
- NNX09AG40G
- NASA OSS
- EAR-0947956
- NSF
- Created
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2012-06-28Created from EPrint's datestamp field
- Updated
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2020-03-09Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences