The geology and geological development of the broken hill lode in the new broken hill consolidated mine, Australia Part III: Petrology and petrogenesis
Titel:
The geology and geological development of the broken hill lode in the new broken hill consolidated mine, Australia Part III: Petrology and petrogenesis
Auteur:
Hodgson, C. Jay
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 22 (1975) nr. 2 pagina's 195-213
Jaar:
1975
Inhoud:
Ten ore types, of three genetic types, are recognized in the mine: those formed by the recrystallization of ore layers rich in carbonates and sulphides, those formed by the diffusion of Ca, Mn, and Fe from ore layers into adjacent weakly mineralized siliceous rocks, and those ore layer rocks modified by the loss of Ca, Mn, and Fe. Some constituents moved at least tens of metres. The method of transport probably was by diffusion through, and/or transport by, a gas phase which was being expelled as the system dehydrated, decarbonated, and desulphidized during metamorphism. Most of the 'metasomatic interaction' between ore lodes and wall rocks occurred early in the history of the area, but some occurred after earliest metamorphic foliation, had formed, and resulted in the formation of 'epigenetic' vein-like bodies of lode rock ('droppers'). Chemically similar but quantitatively minor migration took place during the high-grade metamorphism and subsequent retrograde metamorphic events.
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