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- Title
Fluoritites Produced by Crystallization of Carbonate–Fluoride Magma.
- Authors
Stepanov, Aleksandr S; Aminov, Jovid; Odinaev, Sharifjon; Iskandarov, Farukh Sh; Jiang, Shao-Yong; Karmanov, Nikolai S
- Abstract
Fluorite-dominated rocks are occasionally found in association with carbonatites, but their geologic and petrologic relations are rarely reported. The Dunkeldyk area of the Pamir mountains in south-eastern Tajikistan contains dikes of distinctive rocks composed of calcite, fluorite, celestine-barite, sulfides, apatite, with minor quartz, biotite, and REE fluorcarbonates. The dikes have sharp contacts with the host (meta-)sedimentary rocks and layering with ribbons, ranging from fluorite-bearing calcite carbonatites to fluoritites (rocks with >50% fluorite). The fluoritites are characterized by high Ca, F, Ba, Sr, REE, and S coupled with anomalously low O. The geologic relations and textures suggest a magmatic origin of the dikes from melts close to calcite–fluorite eutectic that experienced nucleation-controlled differentiation during the crystallization of dikes and the formation of fluoritite cumulates in larger intrusions. The Dunkeldyk dikes demonstrate that sizable geological bodies of fluorite-dominated rocks could form from carbonate–fluoride melts originating from the differentiation of alkaline silicate magmas.
- Subjects
TAJIKISTAN; MAGMAS; SEDIMENTARY rocks; CRYSTALLIZATION; APATITE; CARBONATITES; FLUORITE; CHEMICAL weathering
- Publication
Journal of Petrology, 2024, Vol 65, Issue 4, p1
- ISSN
0022-3530
- Publication type
Article
- DOI
10.1093/petrology/egae033