HR: 1340h
AN: V23A-1230    [Abstracts]
TI: The Paddy's Flat Gold District (Murchison, Western Australia), insight on a rheologically and structurally control lode gold deposit
AU: * Thebaud, N
EM: nicolas.thebaud@gmail.com
AF: Mercator Gold Australia Pty Ltd, 41 Kishorn Road, Applecross, WA 6153, Australia
AU: Hollingsworth, D
EM: david.hollingsworth@mercatorgold.com.au
AF: Mercator Gold Australia Pty Ltd, 41 Kishorn Road, Applecross, WA 6153, Australia
AU: Gonzalez-Alvarez, I
EM: Ignacio@mercatorgold.com.au
AF: Mercator Gold Australia Pty Ltd, 41 Kishorn Road, Applecross, WA 6153, Australia
AB: In the North-West of the world class gold producer Yilgarn craton lies the Murchison Goldfield (Western Australia). Several rich deposits mined since the turn of the 19th century suggest that this late-Archaean terrane is highly prospective for gold exploration. Located in the northern part of the Murchison goldfield, the Paddy's Flat District recorded a production of ~2 Moz. The Paddy's Flat Gold District area is located on an N-S trending, steeply east dipping shear on the north western limb of an upright isoclinal fold known as the Polelle syncline. It is hosted in a strained and metamorphosed volcanic and minor sedimentary sequence. Mineralisation within the Paddy's Flat District is not limited to a particular rock type and it is associated with a wide range of lithologies including: (i) intermediate to felsic extrusive volcanics, (ii) intrusive porphyrytic microgranite, (iii) ultramafic volcanic assemblage and (iv) iron rich banded chert. Instead, the mineralisation is highly structurally controled by the Paddy's Flat shear zone which provided fluid-pathways for the mineralising fluid. Regardless of the lithological composition, the mineral assemblage associated with the gold mineralisation consists of quartz, carbonate (ankerite, siderite), sulphides (pyrite, arsenopyrite), fuchsite and sericite assemblage suggesting the introduction of an oxidizing fluid rich in Au, S, As and K ± SiO2. At Paddys Flat the mineralisation is spatially associated with rheologicaly competent units or with domains located at the boundary between rheologically distinct lithologies within the main shear. The fluid pathways provided by the shear zone and the rheological contrast are suggested to be key parameters in the formation of economic lode gold deposit in the Paddy's Flat district.
DE: 3665 Mineral occurrences and deposits
DE: 3690 Field relationships (1090, 8486)
DE: 8010 Fractures and faults
DE: 8034 Rheology and friction of fault zones (8163)
DE: 9623 Archean
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting