Stranger in paradise: liddicoatite from the High Grade Dike pegmatite, southeastern Manitoba, Canada

Abstract

Liddicoatite, locally with cores of highly X-vacant e1baite, occurs in the High Grade Dike pegmatite of the Cat Lake-Winnipeg River pegmatite field, in the southwestern margin of Superior Province of the Canadian Shield. The liddicoatite contains substantial proportions of the elbaite and rossmanite components; the most calcic composi tion analyzed corresponds to (Cao.498Nao.395Do.1 07)(Li 1.396All.I22Mn0.414Feo.06S)AI6(Sis.888AlO.1 d030(OH3.516F 0.484)' Liddicoatite is closely associated with Ca-enriched spessartine Sps89Grs9Alm2 containing :0; 0.30 wt.% F, and with poliucite, which is the only one with detectable Ca (0.26 to 0.44 wt.% CaO) among pollucite sampies from � 70 worldwide localities. This mineral assemblage was the last product of primary, near-solidus crystallization in the peg matite, and its Ca-enriched members have no analogs, individually or collectively, in other Li-tourrnaline-bearing pegmatites of the parent pegmatite field or elsewhere. Our observations support neither mobilization of Ca from pre existing pegmatite minerals, nor influx of Ca from host rocks. Preservation of some Ca throughout the crystallization of the apatite-and microlite-poor pegmatite seems to be probable, although the specific mechanism of such process remains to be identified.

Secondary blue tourmaline after garnet from elbaite-subtype pegmatites; implications for source and behavior of Ca and Mg in fluids

“…Hence, the source of Ca was melt contamination at pre-emplacement stage and during, or slightly after, emplacement to the site of crystallization (post-emplacement stage; Novák et al , 2017. This is consistent with the results of Teertstra et al (1999) and Novák et al (1999). Clearly, evolution of Ca in granitic pegmatites during solidus and subsolidus conditions requires detailed studies of further appropriate localities.…”

“…Calcium may stay available to later stages of primary crystallization (e.g., apatite, liddicoatite, graftonite; e.g., Teertstra et al 1999;Novák et al 1999;Martin and de Vito 2014 and references therein). However, late enrichment of Ca in pegmatites, although it was observed on numerous localities worldwide (e.g.…”

Liddicoatite Tourmaline From Anjanabonoina, Madagascar

“…All of these localities have produced gem-quality tourmaline except for those in Canada and the Czech Republic, which are included for completeness. In Canada, liddicoatite was found in the High Grade Dike of the Cat Lake-Winnipeg River pegmatite field (Teertstra et al, 1999). The tourmaline occurs at two localities in the Czech Republic.…”

“…The presence of liddicoatite in gembearing cavities indicates that Ca was abundant during late-stage pegmatite crystallization. Teertstra et al (1999) postulated that the Ca needed to form liddicoatite could be mobilized from the pegmatite host rocks or the alteration of previously crystallized Ca-bearing minerals (e.g., plagioclase), or the Ca could be geochemically conserved (e.g., as fluoride complexes) during pegmatite crystallization until late stages. While all three of these mechanisms may play a role, it is important to note that in elbaite-subtype pegmatites, liddicoatite is typically found in deposits that are located in or near Carich host rocks .…”

Provenance of the Permian Malužiná Formation sandstones (Malé Karpaty Mountains, Western Carpathians): evidence of garnet and tourmaline mineral chemistry

“…These are the dominant genetic environment of Li-bearing tourmalines including elbaite and fluor-elbaite (e.g. Jolliff et al 1986;Selway et al 1999;Tindle et al 2002), rossmanite , and liddicoatite (Teerstra et al 1999). However, granitic pegmatites usually comprise schorlitic to foititic Selway et al 1999;Bačík et al 2011) and more rarely also dravitic tourmalines Bačík et al 2012).…”