Boulton, C. and Menzies, C.D and Toy, V.G. and Townend, J. and Sutherland, R. (2017) 'Geochemical and microstructural evidence for interseismic changes in fault zone permeability and strength, Alpine Fault, New Zealand.', Geochemistry, geophysics, geosystems., 18 (1). pp. 238-265.
Oblique dextral motion on the central Alpine Fault in the last circa 5 Ma has exhumed garnetoligoclase facies mylonitic fault rocks from 35 km depth. During exhumation, deformation, accompanied by fluid infiltration, has generated complex lithological variations in fault-related rocks retrieved during Deep Fault Drilling Project (DFDP-1) drilling at Gaunt Creek, South Island, New Zealand. Lithological, geochemical, and mineralogical results reveal that the fault comprises a core of highly comminuted cataclasites and fault gouges bounded by a damage zone containing cataclasites, protocataclasites, and fractured mylonites. The fault core-alteration zone extends 20–30 m from the principal slip zone (PSZ) and is characterized by alteration of primary phases to phyllosilicate minerals. Alteration associated with distinct mineral phases occurred proximal the brittle-to-plastic transition (T300–4008C, 6–10 km depth) and at shallow depths (T520–1508C, 0–3 km depth). Within the fault core-alteration zone, fractures have been sealed by precipitation of calcite and phyllosilicates. This sealing has decreased fault normal permeability and increased rock mass competency, potentially promoting interseismic strain buildup.
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|Publisher Web site:||http://doi.org/10.1002/2016GC006588|
|Publisher statement:||Boulton, C., Menzies, C.D, Toy, V.G., Townend, J. & Sutherland, R. (2017). Geochemical and microstructural evidence for interseismic changes in fault zone permeability and strength, Alpine Fault, New Zealand. Geochemistry, Geophysics, Geosystems 18(1): 238-265. 10.1002/2016GC006588. To view the published open abstract, go to https://doi.org/ and enter the DOI.|
|Date accepted:||12 December 2016|
|Date deposited:||22 November 2019|
|Date of first online publication:||25 January 2017|
|Date first made open access:||No date available|
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