Geology of the Cornubian Tin Field 'A Review'

Author : N.J. Jackson
Publication : Bulletin of the Geological Society of Malaysia
Page : 209-237
Volume Number : 11
Year : 1979

Bulletin of the Geological Society of Malaysia, Volume 11, Dec. 1979, pp. 209-237

Geology of the Cornubian Tin Field ‘A Review’


Abstract: Mainstage mineralisation is spatially related to the roof and border zones of several high level, post-kinematic, geochemically specialized, Permian granites. The following types of mineralisation phenomena are recognised and described; 1) pervasive. postmagmatic metasomatisms and alterations 2) hydrothermal breccia pipes 3) metallised and non-metallised pegmatites 4) metallised vein systems 5) metallised replacements. These mineralisation phenomena show definite space-time patterns within the batholith and its environs. Five spatial environments are recognised each, characterised by a particular style of mineralisation at any point in time. Mainstage mineralisation is considered to have been emplaced in four distinct phases, which broadly comprise 1) metasomatisms, pegmatites and hydrothermal breccias 2) early veins of quartz-wolframite-cassiterite, arsenopyrite, alkali feldspar, tourmaline 3) veins and replacements of quartz-cassiterite and cassiterite-sulphides 4) late veins of sulphides.

The main factors which controlled the distribution of mineralisation were; 1) magmatic-hydrothermal history of the intrusive, 2) degree, location and nature of fracturing, 3) location and nature of meteoric hydrothermal convection systems, 4) physico-chemical conditions within the vein environment.