Botany of the Manawatu sand country Journal Paper
- Author
- Carnahan, J.A.
- Year
- 1957
- Journal / Source
- Proceedings of the New Zealand Ecological Society
- Volume
- 5
- Pages
- 17-8
- Keywords
- Tertiary, stratigraphy, Canterbury.
- Summary
- Stratigraphic and sedimentologic studies of the Cretaceo-Tertiary sequence overlying Torlesse rocks in the Coalgate area permit a review of the lithostratigraphy of the region. Much new information has come from borehole logs and cores. Coal measures conformably overlain by shallow marine strata and associated igneous rocks, including View Hill Basalt, are assigned to the Eyre Group (modified name) of upper Cretaceous and possibly Paleocene age. Burnt Hill Group (new name) is erected to accommodate some 200 m of Oligocene-Miocene non-calcareous marine, estuarine, and associated igneous rocks of central and northern Canterbury. Formations include: Homebush Standstone (new name for a massive estuarine deltaic deposit) (oldest unit); Thongcaster Formation of Duntroonian age (new name for a fossiliferous clayey fine sandstone); Wairiri Volcaniclastite (new name for a tuff-breccia deposit); Chalk Quarry Sandstone of Waiauan age (modified name); Chalk Hill Clay; Sandpit Tuff (name now formalised) consisting of sandy and silty tuffs and tuff breccias; Bluff Basalt (name now formalised) including breccia, flow and dike rocks; Harper Hills Basalt (name altered and restricted in usage); Coalgate Bentonite (rank of unit changed) (youngest unit). Burnt Hill Group is overlain by 55 m of sandstone and sandy mudstone of Greenwood Formation, of probable Waipipian age, and up to 40 m of viviantic sands, clays, and gravels of possible Castlecliffian and perhaps younger age which are included in Aitkens Formation (new name). Much of the area is blanketed by Hawera Series outwash gravels which help to obscure the stratigraphic relationships of older formations in surface exposure.