CaltechAUTHORS
  A Caltech Library Service

Adrianite, Ca_(12)(Al_4Mg_3Si_7)O_(32)Cl_6, a new Cl-rich silicate mineral from the Allende meteorite: An alteration phase in a Ca-Al-rich inclusion

Ma, Chi and Krot, Alexander N. (2018) Adrianite, Ca_(12)(Al_4Mg_3Si_7)O_(32)Cl_6, a new Cl-rich silicate mineral from the Allende meteorite: An alteration phase in a Ca-Al-rich inclusion. American Mineralogist, 103 (8). pp. 1329-1334. ISSN 0003-004X. http://resolver.caltech.edu/CaltechAUTHORS:20180801-074217580

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20180801-074217580

Abstract

Adrianite (IMA 2014-028), Ca_(12)(Al_4Mg_3Si_7)O_(32)Cl_6, is a new Cl-rich silicate mineral and the Si,Mg analog of wadalite. It occurs with monticellite, grossular, wadalite, and hutcheonite in altered areas along some veins between primary melilite, spinel, and Ti,Al-diopside in a Type B1 FUN (Fractionation and Unidentified Nuclear effects) Ca-Al-rich inclusion (CAI), Egg-3, from the Allende CV3 carbonaceous chondrite. The mean chemical composition of type adrianite by electron probe microanalysis is (wt%) CaO 41.5, SiO_2 27.5, Al_2O_3 12.4, MgO 7.3, Na_2O 0.41, Cl 13.0, O=Cl –2.94, total 99.2, giving rise to an empirical formula of (Ca_(11.69)Na_(0.21))(Al_(3.85)Mg_(2.88)Si_(7.23))O_(32)Cl_(5.80). The end-member formula is Ca_(12)(Mg_5Si_9)O_(32)Cl_6. Adrianite has the I43d wadalite structure with a = 11.981 Å, V = 1719.8 Å^3, and Z = 2, as revealed by electron backscatter diffraction. The calculated density using the measured composition is 3.03 g/cm^3. Adrianite is a new secondary mineral in Allende, apparently formed by alkali-halogen metasomatic alteration of primary CAI minerals such as melilite, anorthite, perovskite, and Ti,Al-diopside on the CV chondrite parent asteroid. Formation of secondary Cl-rich minerals sodalite, adrianite, and wadalite during metasomatic alteration of the Allende CAIs suggests that the metasomatic fluids had Cl-rich compositions. The mineral name is in honor of Adrian J. Brearley, mineralogist at the University of New Mexico, U.S.A., in recognition of his many contributions to the understanding of secondary mineralization in chondritic meteorites.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.2138/am-2018-6505DOIArticle
Alternate Title:Adrianite, Ca12(Al4Mg3Si7)O32Cl6, a new Cl-rich silicate mineral from the Allende meteorite: An alteration phase in a Ca-Al-rich inclusion
Additional Information:© 2018 Mineralogical Society of America. Manuscript received February 12, 2018; Manuscript accepted May 4, 2018; Manuscript handled by Steve Simon. SEM, EBSD, and EPMA were carried out at the Geological and Planetary Science Division Analytical Facility, Caltech, which is supported in part by NSF grants EAR-0318518 and DMR-0080065. This work was also supported by NASA grant NNX12AJ01G. We thank Mike Zolensky, Makoto Kimura, and associate editor Steve Simon for constructive reviews.
Funders:
Funding AgencyGrant Number
NSFEAR-0318518
NSFDMR-0080065
NASANNX12AJ01G
Subject Keywords:Adrianite, Ca_(12)(Al_4Mg_3Si_7)O_(32)Cl_6, new mineral, wadalite group, alteration mineral, Ca-Al-rich inclusion, Allende meteorite, carbonaceous chondrite
Record Number:CaltechAUTHORS:20180801-074217580
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180801-074217580
Official Citation:Chi Ma, Alexander N. Krot; Adrianite, Ca12(Al4Mg3Si7)O32Cl6, a new Cl-rich silicate mineral from the Allende meteorite: An alteration phase in a Ca-Al-rich inclusion. American Mineralogist ; 103 (8): 1329–1334. doi: https://doi.org/10.2138/am-2018-6505
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:88416
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:01 Aug 2018 16:10
Last Modified:01 Aug 2018 16:10

Repository Staff Only: item control page