Cloncurry Fault Zone: strain partitioning and reactivation in a crustal-scale deformation zone, Mt Isa Inlier
Austin, J.R., and Blenkinsop, T.G. (2010) Cloncurry Fault Zone: strain partitioning and reactivation in a crustal-scale deformation zone, Mt Isa Inlier. Australian Journal of Earth Sciences, 57 (1). pp. 1-21.
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The Cloncurry Fault Zone is a north-northwest-trending zone of complex deformation over 100 km long and up to 7 km wide near the eastern edge of the Mt Isa Inlier. The zone includes mylonites in an anastomosing shear-zone system with variably plunging mineral lineations within a north-northwest subvertical girdle that formed synchronously with north-northwest- and south-southeast-plunging folds. No clear overprinting of lineations in different orientations is observed, and the complexity of the penetrative fabrics can be attributed to strain partitioning during east-northeast contraction, rather than requiring amore complex history of overprinting relations. The mylonites formed at temperatures of 350–5008C, below the *6508C metamorphic peak that occurred during the regional D2 event, and they are superimposed on Maramungee-aged granites (1555–1545 Ma), implying that the majority of fabrics formed during D3. D3 was followed by the development of a D4 sinistral Riedel strike-slip fault system involving east-southeast contraction, which was coincident with massive Na–Ca alteration and brecciation within the zone. Reactivation with a normal component of movement occurred some time after the Jurassic. The Cloncurry Fault Zone is a crustal-scale feature of the Mt Isa inlier that records strain partitioning and a deformation history lasting over 1.5 Ga. KEY WORDS: Isan Orogeny, mylonite, Riedel shear, strain partitioning
|Item Type:||Article (Refereed Research - C1)|
|Keywords:||Isan Orogeny; mylonite; Riedel shear; strain partitioning; strike-slip faulting; transpression|
|FoR Codes:||04 EARTH SCIENCES > 0403 Geology > 040312 Structural Geology @ 50%|
04 EARTH SCIENCES > 0403 Geology > 040313 Tectonics @ 50%
|SEO Codes:||97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 100%|
|Deposited On:||09 Aug 2010 12:51|
|Last Modified:||18 Oct 2013 00:59|
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