Investigations of pegmatite, stockwork and replacement deposits, using geological, whole-rock and mineral chemistry, fluid inclusion, and stable isotope data, were undertaken to establish some of the controls of mineralization in the western Thai Sn-W belt. / Cassiterite was saturated in the late-stage melt in the Nong Sua granitic pegmatite and subsequently with wolframite in orthomagmatic fluids. The latter mixed with external aqueous and aqueous-carbonic fluids of evolved meteoric or metamorphic origin at $ le$650$ sp circ$C and $ le$3.8 kbar. Hydrothermal cassiterite and wolframite crystallized as a result of increasing $fO sb2,$ fluid mixing, and cooling. At the Pilok stockwork deposits tourmalinization was followed by successive wolframite-K-feldspar deposition and cassiterite-sulphide greisen mineralization. Tin was remobilized by reduced metamorphic or evolved magmatic-meteoric aqueous-carbonic fluids. Cassiterite was deposited at 300-450$ sp circ$C in response to increasing $fO sb2,$ pH, or decreasing temperature. Limited data on the Takua Pit Thong replacement suggest that cassiterite was deposited from aqueous fluids at $ ge$500$ sp circ$C, but metamorphic aqueous-carbonic fluids were also involved. / The depth of emplacement was one of the major controls on mineralization style. Aqueous-carbonic fluids in the western Thai, and other Sn-W belts, are a consequence of a moderately deep level of emplacement; hypersaline orthomagmatic fluids are associated with sub-volcanic Sn-W mineralization.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.70272 |
| Date | January 1992 |
| Creators | Linnen, Robert L. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Geological Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001270602, proquestno: AAINN74578, Theses scanned by UMI/ProQuest. |
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