Pahau River, Culverden, Hurunui District, Canterbury Region, New Zealandi

Regional Level Types
Pahau River	River
Culverden	- not defined -
Hurunui District	District
Canterbury Region	Region
New Zealand	Country

Basalt from a nearby sub-marine eruptive centre, with interbedded agglomerate lenses, limestone, and conglomerate with pebbles of agglomerate in a limestone matrix. In places, the agglomerate shows cavities filled with zeolites.

Marine fossils are also noted nearby, especially the Cascade Creek area, a tributary of the Pahau at the Grampions Homestead along Cascade Road. Much of the fossil sites are on private property.

The location is reported as one mile upstream from the confluence of Cascade Stream and the Pahua River. It is stated as on private property.

Calcite is found as thin white to creamy transparent crystals, often lining cavities, as rhomb clusters, or single crystals, often associated with the other species.

Analcime as white or glassy crystals, lining cavities, occurring alone or with other species.

Natrolite as white to colourless acicular needles, often with square blocky terminations, showing a flat pyramid. Sizes range from several cms long to micro. Found with apophyllite and analcime. The source states the needles are large for New Zealand, but virtually impossible to clean without damaging the crystals.

Apophyllite as white, yellow, and pale blue-green crystals, larger platy crystals, or forming clusters of smaller blocky crystals with large pyramid faces. The pale blue-green coloured crystals can be transparent to translucent, but over time loses colour, and goes opaque from dehydration. The crystals can be found alone, but more often associated with the other species.

Phillipsite as minute white or clear simple twins, or cruciform twins, often associated with calcite, and analcime. Crystals are found alone or in mounds. This was originally reported as harmotone, a barium rich phillipsite. The source states barium rich phillipsite was found in one cavity but the majority showed no barium.

Hyalophane is a barium rich feldspar, originally reported from the site. The source dating from the 1990's states no barium was subsequently found, and is normal feldspar as clear, glassy or transparent crystals, with multiple terminations, some single crystals but normally in groups.

More up to date information needed on harmotone, and hyalophane.

Other Regions, Features and Areas containing this locality

References