Lithological and paleontological content of the Carboniferous-Jurassic Canterbury Suite, South Island, New Zealand

Abstract

The late Paleozoic and Mesozoic quartzo-feldspathic Canterbury Suite contains a wide range of detrital lithotypes and facies, representing many depositional environments. The stratification, sedimentary structures, and fossils characteristic of 11 lithotypes are described and interpreted in terms of probable depositional environments. Fifteen recognisable faunal zones represent only part of the total time span of the Canterbury Suite (Carboniferous to late Jurassic). There is no record of early Permian, latest Permian and early Triassic, or latest Triassic through middle Jurassic, except for a single collection representing the Ururoan Stage (early Jurassic). All but two of the faunal assemblages consist mainly of epifaunal and nektonic species of low abundance and diversity. Infaunal species are virtually absent. The assemblages are characteristic of continental shelf environments. Marginal marine and non-marine depositional environments, coarse detrital conglomerates, and vascular plant material are common in the eastern part of the outcrop area. Thev become less abundant towards the west, and in the extreme west of the outcrop area, conglomerate is essentially absent, plant fossils very sparse, and probable deep marine facies relatively common. These trends show that the detritus was transported from east to west, and that the source rocks lay east of present-day New Zealand. Conglomerate and sandstone composition shows that during Triassic time the source area consisted of granodiorite and minor schistose and gneissic metamorphic rocks, but that by late Jurassic time acid volcanic rocks were also abundant.