Tectonic map of Central Otago based on Landsat imagery

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Abstract
Low sun angle Landsat imagery permits analysis of late Cenozoic deformation of Central Otago because of preservation of the deformed Tertiary peneplain developed on schist and greywacke together with the contrast in Landsat expression between basin sediments and older rocks. The degree of embayment of fault-controlled mountain fronts in Central Otago by erosion and alluvial-fan development permits determination of relative age of faulting using Landsat, but late Quaternary fault scarps within structural depressions are only rarely visible. Landsat shows that Cenozoic structures of Central Otago may be visualised on two scales. The smaller scale structures are individual northeast-or northwest-trending, fault-bounded ranges and basins, 5–20 km wide. Sets of ranges and basins are grouped into northwest-elongated structural provinces, 40–60 km wide. From northeast to southwest, starting at the Waitaki River, these include (1) a set of northwest-trending ranges with very few basins south to the Waihemo, Stranraer, and Hawkdun Faults; (2) a set of northeast-trending ranges and basins; and (3) step-faulted schist highlands with very few basins. Northwest elongation of these provinces is parallel to bedrock trends including fold axes in schist and the ophiolite belt. These provinces may represent different responses of crustal rocks to contractile strain across the plate boundary.