Fluids and hydrothermal alteration assemblages in a Devonian gold-bearing hot-spring system, Rhynie, Scotland.

M. Barron, S. Hillier, Clive Maitland Rice, K. Czapnik, John Parnell

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Hydrothermal alteration at Rhyme, Aberdeenshire, Scotland, is concentrated along a fault zone, which juxtaposes surface deposits and the mineralised feeder zone to the Rhyme hotspring system. Mineralisation consists of breccias and veins filled with quartz, chert, calcite, K-feldspar and pyrite. Associated pervasive alteration comprises a high-temperature K-feldspar-quartz-illite facies (formed at 250-350degreesC), a medium-temperature mixed layered illite/smectite-quartz-K-feldspar-chlorite-calcite facies (formed at 150-200degreesC) and a low-temperature mixed layered illite/smectite-chlorite-calcite facies (formed at 100 to + 150degreesC). The fluids responsible for mineralisation were mainly moderate- to high-temperature (T-h=91-360degreesC), low-salinity (<0.2 to 2.9 wt.% NaCl eq.) H2O-NaCl-heated meteoric fluids comparable to modern and ancient hot-spring systems. The migration of these fluids was mainly restricted to a major fault zone bounding the Devonian basin. Fluids responsible for mineralisation, alteration and cementation elsewhere in the basin were low-temperature (T-h 57 to 161 degreesC), low- to high-salinity (<0.2 to 18 wt.% NaCl eq.) H2O-NaCl fluids, which resemble basinal brines.

Original languageEnglish
Pages (from-to)309-324
Number of pages15
JournalTransactions of the Royal Society of Edinburgh-Earth
Volume94
Publication statusPublished - 2004

Keywords

  • epithermal gold mineralisation
  • fluid inclusions
  • hot springs
  • siliceous sinters
  • X-ray diffraction
  • OHAAKI GEOTHERMAL SYSTEM
  • NEW-ZEALAND
  • LACUSTRINE MUDROCKS
  • NORTHERN SCOTLAND
  • EPITHERMAL VEINS
  • INCLUSIONS
  • DEPOSIT
  • MINERALIZATION
  • DISTRICT
  • ABERDEENSHIRE

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