Mineralogical domains within gold provinces
- Authors: Hughes, Martin , Phillips, Neil
- Date: 2015
- Type: Text , Journal article
- Relation: Transactions of the Institutions of Mining and Metallurgy, Section B: Applied Earth Science Vol. 124, no. 3 (2015), p. 191-204
- Full Text: false
- Reviewed:
- Description: Mineralogical domains use hypogene minerals (i.e. minerals not modified by weathering) and related geochemical characteristics of mineral occurrences, not only ore deposits, to subdivide large mineralised regions. Their use in the Victorian gold province is described using readily available historical data and field checking, and this is a scheme that has not required modification since 1997.The Victorian province is typical of sediment-hosted hydrothermal ores in metamorphic terrains (often termed orogenic gold deposits). Five distinctly different mineral assemblages are used to subdivide all Victorian gold occurrences into eight domains up to hundreds of kilometres in length and tens of kilometres in width. These parallel the regional structural trend and most are closely associated with, or sharply bounded by, major regional-scale faults. Seismic work has shown these faults to be listric thrusts, which flatten into a zone of duplexed greenstones overlying older basement rocks in the deeper crust. Although not defined genetically or temporally, mineralogical domains provide an additional variable related to fluid flow to assist genetic interpretation such as the scale at which a combination of processes operates, permitting predictions as to the origin of the fluids and their pathways. The variations in mineralogy in Victorian gold occurrences indicate that ore fluid compositions differed significantly between adjacent domains, and between areas overlying different regions of deeper crust. The pattern of domains gives clues to the existence of multiple mineralising events and to the degree of overprinting of these events. Domains also assist genetic comparisons by projection into similar adjoining regions to create new domains, for example Tasmania (Mathinna domain and Lefroy sub-domain), NSW (Cobar domain) and New Zealand (Reefton domain). The domainal pattern has application to mineral exploration, metallurgy and environmental issues. Mineralogical domains could be applied elsewhere, particularly in the study of difficult-to-subdivide sedimenthosted gold ores and Archaean greenstone-hosted gold, and possibly for other commodities, especially those that occur as hydrothermal ores. © 2015 Institute of Materials, Minerals and Mining and The AusIMM.
Giant placers of the Victorian gold province
- Authors: Hughes, Martin , Carey, Stephen , Phillips, Neil
- Date: 2004
- Type: Text , Journal article
- Relation: Society of Economic Geologists Vol. 56, no. (2004), p. 10-18
- Full Text:
- Description: Victoria has yielded 2500 tonnes or almost 2 per cent of the world’s gold, mostly mined between 1851 and 1910. Some 55 per cent was placer gold from modern and palaeostream systems, and from eluvial deposits. The rest came from primary quartz vein-related deposits........
- Description: C1
- Description: 2003000794
Gold
- Authors: Carey, Stephen , Phillips, G. N. , Hughes, Martin , Arne, Dennis , Bierlein, Frank , Jackson, T. , Willman, C. E.
- Date: 2003
- Type: Text , Book chapter
- Relation: Geology of Victoria Chapter p. 377-433
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- Reviewed:
- Description: B1
- Description: 2003000628
Palaeodrainage development of the West Victorian Uplands, Victoria, Australia
- Authors: Carey, Stephen , Hughes, Martin
- Date: 2002
- Type: Text , Conference paper
- Relation: Paper presented at Victoria Undercover, Benalla 2002 Conference Proceedings and Field Guide, Benalla, Australia : March 2002 p. 147-154
- Full Text:
- Reviewed:
- Description: E1
- Description: 2003000193
Permian Sediments of the Honeysuckle Plain Graben, Benalla, Victoria
- Authors: Hughes, Martin
- Date: 2002
- Type: Text , Conference paper
- Relation: Paper presented at Victoria Undercover, Benalla 2002 Conference Proceedings and Field Guide, Benalla, Australia : March 2002 p. 147-154
- Full Text: false
- Reviewed:
- Description: E1
Regolith of the West Victorian Uplands, Victoria, Australia
- Authors: Carey, Stephen , Hughes, Martin
- Date: 2002
- Type: Text , Conference paper
- Relation: Paper presented at Victoria Undercover, Benalla 2002 Conference Proceedings and Field Guide, Benalla, Australia : March 2002 p. 147-154
- Full Text:
- Reviewed:
- Description: E1
- Description: 2003000193
Tectonic and economic implications of trace element, Ar-40/Ar-39 and Sm-Nd data from mafic dykes associated with orogenic gold minerals in central Victoria, Australia : reply
- Authors: Bierlein, Frank , Hughes, Martin , Dunphy, J. , McKnight, Stafford
- Date: 2002
- Type: Text , Journal article
- Relation: Lithos Vol. 63, no. 1-2 (Jul 2002), p. 119-123
- Full Text: false
- Reviewed:
Tectonic and economic implications of trace element, Ar-40/Ar-39 and Sm-Nd data from mafic dykes associated with orogenic gold mineralisation in central Victoria, Australia
- Authors: Bierlein, Frank , Hughes, Martin , Dunphy, J. , McKnight, Stafford , Reynolds, P. , Waldron, H.
- Date: 2001
- Type: Text , Journal article
- Relation: Lithos Vol. 58, no. 1-2 (Aug 2001), p. 1-31
- Full Text: false
- Reviewed:
- Description: Mafic to intermediate dykes are spatially and temporally closely associated with major post-tectonic granitic complexes in the western Lachlan Orogen of SE Australia. These dykes, which range petrographically from basaltic to andesitic, are concentrated within several, north- to northwest-trending zones and were emplaced during two broad intervals of extensive magmatic activity during the Silurian–Devonian period. Geochemical and Sm–Nd isotopic characteristics of these mafic intrusives are consistent with their formation in a complex subduction-related tectonic setting. Interaction between mantle-wedge material, sinking oceanic crust and input from the overlying continental crust resulted in the petrological and geochemical variations displayed by these and more felsic dykes throughout the study region. Field evidence and 40Ar/39Ar data show that in the eastern part of the Stawell Zone and in the northwest portion of the Bendigo Zone, mafic dyke were intruded between 410 and 400 Ma (Late Silurian/Early Devonian). Further emplacement in the Bendigo Zone and the eastern part of the Melbourne Zone took place at between 375 and 365 Ma (Middle to Late Devonian). Episodic mantle-derived magmatism was possibly related to step-wise rollback, slab detachment or changes in the angle and rate of westward subduction in response to periodically occurring accretionary pulses. A close spatial and temporal relationship also exists between the dykes and orogenic gold mineralisation in the central Victorian gold province. Mafic to intermediate dykes both crosscut, and are host to, mineralisation in a number of goldfields. Although there is little evidence for a direct genetic association, the two processes are linked by the common utilisation of translithospheric structures, which facilitated the rapid ascent into shallow crustal levels of both mantle-derived magma and crustal-scale ore-forming fluid systems. Previous studies have suggested that transfer of heat into the crust via ascending mafic mantle magmas can provide a thermal engine which triggers and sustains extensive crustal melting, thus explaining the commonly observed close association of mafic to intermediate and felsic intrusive suites. This study supports the viability of this mechanism and in addition, indicates that a causal link exists between the formation of mantle magmas in collisional zones and the generation of orogenic gold deposits.
- Description: C1