The Paparoa Tectonic Zone

Abstract

The Paparoa Tectomc Zone (new name) extends for 120 miles from the Alpine Fault at the Hok1tika River to Kongahu Point, west Nelson, thus obliquely crossing the Paparoa Range. In the Late Tertiary and Quaternary, the zone was folded and fractured in a scissors movement, pivoting northeast of Greymouth, and up-faulting eastern blocks in the north and western ores in the south. A previous scissors movement along the same zone but in the opposite sense had occurred in late Cretaceous and early Tertiary times. The areas of down-faulting and thickest sedimentary fill are indicated by their coincidence with the highest ranks of the Brunner coals; and coarse breccias and conglomerates, extending outwards from the zone at several localities, were produced by vigorous faulting about uppermost Eocene times. Some Mwcene faulting also occurred, perhaps accounting for the absence of lower Tertiary beds in the Kawhaka bore. Orogenic movements during the Mwcene-Quaternary were accompanied by reverse faulting and overfoldmg, and the Paparoa and Papahaua Ranges probably were produced by high-angle overthrusting. In contrast the late Cretaceous-early Tertiary movements were accompanied by normal faulting. Changes in the direction of Pnncipal Honzontal Stress in the zone and their implications on the history of the Alpine Fault are discussed.

Sandstone diagenesis related to varying burial depth and temperature in Greymouth Coalfield, South Island, New Zealand

“…14), which shows that a theoretical line of maximum reflectance increase runs diagonally from the ground surface in the west to the deepest sediments in the east. The indicated configuration of isoreflectance surfaces supports a model of sediment deposition and coalification in a basin created by normal faulting, with subsequent tilting by reversal of major fault movement (e.g., Laird 1968). It also supports our earlier suggestion that drillholes do not penetrate the rock perpendicular to isoreflectance surfaces, reinforcing the conclusion that the reflectance gradient of R 0 ( ma x) 0.32%/km should be treated as a minimum.…”

Evolution and eversion of a tertiary sedimentary basin, Paparoa Range, West Coast, South Island, New Zealand: Evidence from fission‐track dating

“…2). This line of maximum coal rank parallels the Paparoa Tectonic Zone of Laird (1968). Since coal rank in this basin is related to burial depth, it would suggest that maximum burial is associated with this tectonic zone where the Lower Buller Fault (Fig.…”

“…Spontaneous confined track lengths were measured as described by Seward (1989). Ages (Table 1) were calculated using the C, factor approach (Hurford & Green 1983) with a mean £ value of 338 ± 12 for dosimeter glass SRM962 and the Fish Canyon Tuff Laird (1968) by converting Suggate's (1959) rank to percent reflectance using the graph in Nathan et al (1986). zircon (Seward & Tulloch 1991). The statistical uncertainties on the ages are the standard error as defined by Green (1981) and incorporate errors from the induced and spontaneous tracks as well as those of the glass standard.…”

Stratigraphic nomenclature for the cretaceous-lower Quaternary rocks of Buller and North Westland, West Coast, South Island, New Zealand

“…The Paparoa Coal Measures crop out mainly in the southern part of the Paparoa Range. The formation has been found in drillholes further south (Laird 1968), and is probably present at Kowhitirangi hill (Gage & Wdlman 1944). Although it contains distinct lithological units which were mapped within the Greymouth Coalfield as separate' formations by Gage (1952), most of the units are oJ local extent only.…”