Whangārei volcanic field
Whangārei volcanic field | |
---|---|
Puhipuhi-Whangarei volcanic field | |
Highest point | |
Ma | |
Mountain type | Volcanic field |
Type of rock | basaltic and dacicitic intra-plate monogenetic[1] |
Last eruption | 260 ka[2] |
The Whangārei volcanic field (Puhipuhi-Whangarei volcanic field) is an area of intra-plate monogenetic volcanism located near the city of Whangārei, North Island, New Zealand.[1] It was last active between 260,000[2] to 319,000 years ago[3] and continues to be potentially active as a low-velocity seismic zone in the crust exists beneath Whangārei, which is interpreted to be a body of partial melt.[4] This mantle source has been coupled to the lithosphere for about 8 million years.[2] As the field has potentially been active at low frequency for millions of years, with 100,000 years or more between events it might best be regarded as dormant.[1] The recent vents active in the last million years include some dacite in composition. Composition details are freely available for most of the field but many vents do not have ages.[2]
Geology
Volcanics
These volcanoes are part of the eastern Northland volcanic belt which includes the monogenetic
Non-volcanics and tectonics
The hilly landscape to the west of Whangārei is from uplifted Waipapa Terrane greywacke deposits from ocean floor sediments first laid down several hundred millions ago off the coast of Gondwanaland. There are some coal measures, sandstone, and limestone from late Eocene and Oligocene (Te Kuiti Group) sediments laid on top of the greywacke basement. On top of these contributing to many hills are often more clay like deposits originally from the floor of the Pacific Ocean of 80-25 million years ago. About 25 million years ago these deep-sea sediments were uplifted as the
List of volcanoes
References
- ^ ISSN 0377-0273.
- ^ S2CID 219440898.
- ^ "Project: The evolution of basaltic volcanism in Northland in space and time Earthquake Commission Grant (project 09/U585)" (PDF). Retrieved 22 January 2023.
- S2CID 85512500.
- ^ GNS:NZ active fault database
- ^ S2CID 128957126.
- ^ a b Beetham, R. D.; McSaveney, M.; Dellow, G.; Rosenberg, M.; Johnston, D.; Smith, W. (2004). "A review of natural hazards information for Northland Region" (PDF). Retrieved 23 January 2023.
- ^ Geological Society of New Zealand. p. 27. Archived from the original(PDF) on 4 March 2009.
- ^ a b NZ TopoMap:Hikurangi
- ^ a b c d e f g GNS:1:250000 geological map NZ
- ^ a b NZ TopoMap:Whakapara
- ^ a b NZ TopoMap:Apotu
- ^ a b NZ TopoMap:Parakiore
- ^ a b NZ TopoMap:Hurupaki
- ^ "Mount Parihaka name corrected". 19 July 2005. Archived from the original on 20 January 2009. Retrieved 14 August 2008.
- ^ a b NZ TopoMap:Mount Parihaka
- ^ a b NZ TopoMap:Maungakaramea
- ^ a b NZ TopoMap:Maungatapere
- ^ a b NZ TopoMap:Onerahi