| Abstract: | Alkali-deficient tourmalines are found in albitized rocks from the hanging-wall of the Sullivan Pb-Zn-Ag deposit (British Columbia, Canada). They approximate the Mg-equivalent of foitite with an idealized formula D???(Mg2Al)Al6Si6O18(BO 3)3(OH)4. Major chemical substitutions in the tourmalines are the alkali-defect type [Na*(x) + Mg*(Y) = ???(X) + Al(Y)] and the uvite type [Na*(X) + Al(Y) = Ca(X) + Mg*(Y)], where Na* = Na + K, Mg* = Mg + Fe + Mn. The occurrence of these alkali-deficient tourmalines reflects a unique geochemical environment that is either alkali-depleted overall or one in which the alkalis preferentially partitioned into coexisting minerals (e.g. albite). Some of the alkali-deficient tourmalines have unusually high Mn contents (up to 1.5 wt.% MnO) compared to other Sullivan tourmalines. Manganese has a strong preference for incorporation into coexisting garnet and carbonate at Sullivan, thus many tourmalines in Mn-rich rocks are poor in Mn (<0.2 wt.% MnO). It appears that the dominant controls over the occurrence of Mn-rich tourmalines at Sullivan are the local availability of Mn and the lack of other coexisting minerals that may preferentially incorporate Mn into their structures. |
| Genre: | Article |
| ProdID: | 70019425 |
| Citation Author: | Jiang, S. -Y.; Palmer, M. R.; Slack, J. F. |
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| Citation End Page: | 860 |
| Citation Issue: | 6 |
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| Citation Language: | English |
| Citation Larger Work Title: | Mineralogical Magazine |
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| Citation Number Of Pages: | 8 |
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| Citation Search Results Text: | Alkali-deficient tourmaline from the Sullivan Pb-Zn-Ag deposit, British Columbia; 1997; Article; Journal; Mineralogical Magazine; Jiang, S. -Y.; Palmer, M. R.; Slack, J. F. |
| Citation Start Page: | 853 |
| Citation Volume: | 61 |
| Citation Year: | 1997 |
| Type: | citation/reference |
| Text: | Alkali-deficient tourmaline from the Sullivan Pb-Zn-Ag deposit, British Columbia; 1997; Article; Journal; Mineralogical Magazine; Jiang, S. -Y.; Palmer, M. R.; Slack, J. F. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 1997 00:00 -0600 |
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