Maitai Group Research Articles

New fossil localities in the Maitai Group, Nelson, and comments on its age

Abstract The ammonoids ?Episagiceras aff. noetlingi Haniel and Duvilleoceras woodmani Waterhouse, previously known only from the Greville Formation (Maitai Group) of D'Urville Island, are recorded from boulders of Greville-Jike lithology in the Maitai and Wairoa Rivers, eastern Nelson. Although stratigraphic evidence favours retention of the formation in the Maitai Group its age is uncertain. According to W. M. Furnish and colleagues the Greville ammonoids indicate an Early Triassic age but]. B. Waterhouse maintains that brachiopods in the upper part of the Maitai Group (Stephens Formation) have Permian affinities. Until independent evidence is obtained (such as that from conodont zonation), and the world Permian-Triassic boundary satisfactorily defined, it is not possible to assign a definite age to the Greville Formation, although a Permian age appears likely.

New fossil localities in the Richmond Group, Nelson

Abstract A fossiliferous inlier of Late Triassic (Otapirian) rocks is reported from Packers Creek, Maitai Valley, Nelson. The inlier is 10 km north-east of previously mapped Triassic rocks of East Nelson and is associated with the Waimea Fault, separating Permian volcanics (Brook Street Volcanics) in the west from Permian sediments (Maitai Group) in the east.

The Rai Sandstone in the Dun Mountain area, East Nelson

Abstract In the Dun Mountain area, East Nelson, the Rai Sandstone of the Permian Lee River Group .consists of over 200 m of well- to poorly-bedded grey sandstone and dark-grey mudstone with scattered Atomodesma fragments. Locally the formation contains abundant fragments and scattered complete casts of Atomodesma sp.? aff. trechmanni (Marwick) and worm tubes, and thus may bePuruhauan. It was probably deposited in an outer-shelf, continental-slope environment. Mapping has shown that it is now bounded on its east and west sides by tectonic melanges so that previous interpretations of a westward younging sequence of Pelorus, Lee River and Maitai Groups, cannot be substantiated. Instead, the possible Puruhauan age of the Rai Sandstone and the lithologic similarities between the Pelorus Group, Maitai Group, and the Rai Sandstone suggest that the three units may be in part contemporaneous.

A major overthrust within the maitai group? Comment

A major overthrust within the maitai group? Comment

The Geology of Dun Mountain, Nelson, New Zealand

The sedimentary and volcanic rocks of the Dun Mountain area belong to the Te Anau and Maitai Groups of probably Permian age. The Te Anau Group includes the Little Twin Formation (new), composed of tufTaceous argillite and greywacke with fragments of Atomodesma (Little Twin Argillite Member), and fine-grained spilite (Little Twin Spilite Member), above and interdigitating with the argillite; and the Pelorus Greywacke (new).The lower formations of the Maitai Group (those examined in this paper) are the Rangitoto Formation and the Greville Argillite Formation. The Rangitoto Formation is subdivided into the Rangitoto Volcanic Breccia Member at the base, the Rangitoto Marble Member, and at the top the Rangitoto Greywacke Member. Calcite from the marble has been disseminated by heat from ultrabasic rocks giving in some places calc-silicate rocks and in others calcite replacement of feldspar.The Te Anau and Maitai Groups form an anticline with its axis along the Dun Mountain – Little Twin ridge. The ult...

Stratigraphy of the lower part of the Maitai Group, Nelson

Summary The lower part of the Maitai Group, previously referred to as the limestone of Wooded Peak by Hochstettcr (1864), the Maitai Limestone by McKay (1878), and the Rangitoto Formation by Wellman (1957), is subdivided into five formations. The contact with the Te Anau rocks and ultramafics to the east is locally faulted.