# South Auckland volcanic field

The South Auckland volcanic field, also known as the Franklin Volcanic Field, is an area of extinct monogenetic volcanoes around Pukekohe, the Franklin area and north-western Waikato, south of the Auckland volcanic field. The field contains at least 82 volcanoes, which erupted between 550,000 and 1,600,000 years ago.

## Features

The field extends from Pukekiwiriki east of Papakura in the north and Pukekawa in the south. The field contains at least 82 volcanoes, and is older than the Auckland volcanic field to the north. The youngest volcanoes are likely the Bombay Hills shield volcano, which erupted an estimated 600,000 years ago, and Pukekohe Hill, the largest shield volcano of the field, which erupted an estimated 550,000 years ago. The largest tuff ring in the field is Onewhero maar which is 2.7 km (1.7 mi) in diameter and was formed 880,000 years ago. The field can be divided into three broad geographic areas: the north-eastern section, which consists of eroded remnants of lava flows and scoria cones, some of which are found in the south-western Hunua Ranges, the southern section to the south of the Waikato River, which features many of the more recent and better preserved scoria cones, and the central section, which forms much of the low-lying land of the Pukekohe area, between the Manukau Harbour and Waikato River.

## Context
### Relations to other volcanic activity

Other basaltic volcanic fields that are also now thought to represent intraplate volcanism active in the Pleistocene are adjacent from the south in a more recent to the north trend. As already mentioned the younger Auckland volcanic field is to its immediate north. To the south west is the older Ngatutura volcanic field which was active between 1,830,000 and 1,540,000 years ago and these locations fit with the south north trend being related to the opening of the Hauraki Rift in the Miocene or fracturing of the lithosphere. Further south is the Alexandra Volcanic Group. To its west, are the even older volcanoes associated with the Northland-Mohakatino volcanic belt (Mohakatino Volcanic Arc) which are of a subduction-related origin but which include the still active Mount Taranaki at the southern end of this belt. To the south and east, visible on the horizon from the Bombay Hills are back arc volcanoes. These include the volcanoes of the Taupō Volcanic Zone to the south which have now been continuously active for over 2 million years. This was also the time that activity ceased in the extinct volcanoes of the Coromandel Peninsula in the Coromandel Volcanic Zone to the east.

### Tectonics

Many of the volcanoes are related to known fault structures as shown on a map on this page. The Auckland region lies within the Australian Plate, about 400 kilometres (250 mi) west of its plate boundary with the Pacific Plate. The volcanoes are located south of the Auckland volcanic field which is also part of what has been termed the Auckland Volcanic Province. The structure of the Auckland regional faults and the resulting fault blocks is complex but like the volcanic field their locations can be postulated to be related to gravitational variations and where the Stokes Magnetic Anomaly passes through this section of the North Island.
A north south line of central volcanoes is orientated along the Drury Fault. These extend from Papakura through and beyound the Bombay Hills. While the western margin of the belt is defined by the north-south Wairoa North Fault the eastern margins have at least three east-west fault lines. The unnamed most northern of these was presumably followed by the basaltic extrusion that extended all the way to the Morley Road tuff rings. The volcanoes along the lines of the Waiuku Fault and to the south the Waikato Fault that is also followed by the mouth of the Waikato River suggest that there has been strong volcano-tectonic relationships during the fields historic eruption activity.

## Identification

The volcanic nature of the Tuakau and Pukekohe areas was first identified by Ferdinand von Hochstetter in 1859, however the first volcanic cones only began to be identified in the mid-20th century.

## List of volcanoes

| Volcanoes | Age (thousand years) | Height | Location (Coordinates) | Images |
| Aka Aka Tuff Ring (Kawaka) | | 38 metres (125 ft) | 37°18′00″S 174°47′28″E﻿ / ﻿37.300063°S 174.791018°E﻿ / -37.300063; 174.791018 | |
| Ararimu | | 234 metres (768 ft) | 37°07′41″S 175°02′22″E﻿ / ﻿37.127977°S 175.039323°E﻿ / -37.127977; 175.039323 | |
| Bald Hill Tuff Rings | | 147 metres (482 ft) | 37°13′55″S 174°48′09″E﻿ / ﻿37.232076°S 174.802456°E﻿ / -37.232076; 174.802456 | |
| Ballards Road | | 215 metres (705 ft) | 37°13′28″S 174°48′14″E﻿ / ﻿37.224438°S 174.803753°E﻿ / -37.224438; 174.803753 | |
| Barriball Road Cone | 1,000 ka | 109 metres (358 ft) | 37°13′29″S 174°48′15″E﻿ / ﻿37.224691°S 174.804062°E﻿ / -37.224691; 174.804062 | |
| Beaver Road Vent | | 172 metres (564 ft) | 37°12′45″S 174°59′38″E﻿ / ﻿37.212489°S 174.993759°E﻿ / -37.212489; 174.993759 | |
| Bellemys | | 235 metres (771 ft) | 37°07′39″S 175°01′12″E﻿ / ﻿37.127475°S 175.019926°E﻿ / -37.127475; 175.019926 | |
| Belle Fleur | | 172 metres (564 ft) | 37°12′39″S 175°00′11″E﻿ / ﻿37.210712°S 175.003093°E﻿ / -37.210712; 175.003093 | |
| Bluff Road Vent | | 140 metres (460 ft) | 37°15′34″S 175°00′44″E﻿ / ﻿37.259477°S 175.012179°E﻿ / -37.259477; 175.012179 | Background landscape near Bluff Road Vent, south of the Synlait factory, Pōkeno |
| Bombay Cones | 600 ka | 331 metres (1,086 ft) | 37°11′14″S 175°00′13″E﻿ / ﻿37.187134°S 175.003491°E﻿ / -37.187134; 175.003491 | The Bombay Cones are in the center of this view from Mount Puketutu towards the northwest. |
| Buckland Vent | | 59 metres (194 ft) | 37°13′47″S 174°57′04″E﻿ / ﻿37.229689°S 174.951236°E﻿ / -37.229689; 174.951236 | |
| Dominion Road Tuff Ring | | 109 metres (358 ft) | 37°15′20″S 174°58′59″E﻿ / ﻿37.255434°S 174.983169°E﻿ / -37.255434; 174.983169 | |
| Douglas Road Vent (Pollock Rd shield volcano) | | 100 metres (330 ft) | 37°13′06″S 174°52′05″E﻿ / ﻿37.218403°S 174.867973°E﻿ / -37.218403; 174.867973 | |
| Drury Hills | | 246 metres (807 ft) | 37°06′50″S 174°59′33″E﻿ / ﻿37.114020°S 174.992493°E﻿ / -37.114020; 174.992493 | |
| Elbow Tuff Rings | | 27 metres (89 ft) | 37°17′04″S 174°49′52″E﻿ / ﻿37.284566°S 174.830979°E﻿ / -37.284566; 174.830979 | |
| Fitzgerald Road Vent | | 40 metres (130 ft) | 37°06′47″S 174°57′59″E﻿ / ﻿37.113094°S 174.966521°E﻿ / -37.113094; 174.966521 | |
| Glass Cone and Kellyville Tuff Ring | 1,480 ka | 111 metres (364 ft) | 37°16′30″S 175°03′19″E﻿ / ﻿37.275108°S 175.055291°E﻿ / -37.275108; 175.055291 |
| Helenslee Road Tuff Ring | | 116 metres (381 ft) | 37°14′19″S 175°00′09″E﻿ / ﻿37.238645°S 175.002524°E﻿ / -37.238645; 175.002524 |
| Helvetia Tuff Ring | | | 37°11′35″S 174°52′23″E﻿ / ﻿37.193°S 174.873°E﻿ / -37.193; 174.873 | |
| Hill Road Tuff Ring | | 3 metres (9.8 ft) | 37°15′35″S 174°49′29″E﻿ / ﻿37.259763°S 174.824803°E﻿ / -37.259763; 174.824803 | |
| Hunua Falls | | | 37°04′06″S 175°05′24″E﻿ / ﻿37.068465°S 175.089933°E﻿ / -37.068465; 175.089933 | Hunua Falls volcano is to the west (left) of the waterfall in this picture |
| Ingram Road Tuff Rings | | 80 metres (260 ft) | 37°10′03″S 174°57′49″E﻿ / ﻿37.167623°S 174.963546°E﻿ / -37.167623; 174.963546 | |
| Jerico Road Vent | | 148 metres (486 ft) | 37°12′02″S 174°57′24″E﻿ / ﻿37.200509°S 174.956651°E﻿ / -37.200509; 174.956651 | |
| Kauri Road Vent | | 251 metres (823 ft) | 37°20′49″S 174°54′14″E﻿ / ﻿37.346941°S 174.903813°E﻿ / -37.346941; 174.903813 | |
| Klondike Cone | | 251 metres (823 ft) | 37°20′18″S 174°54′32″E﻿ / ﻿37.338347°S 174.908968°E﻿ / -37.338347; 174.908968 | |
| Mangatawhiri Cone | | 42 metres (138 ft) | 37°11′48″S 175°05′53″E﻿ / ﻿37.196538°S 175.098003°E﻿ / -37.196538; 175.098003 | |
| Mangatawhiri Tuff Ring | | 42 metres (138 ft) | 37°12′35″S 175°05′24″E﻿ / ﻿37.209678°S 175.089867°E﻿ / -37.209678; 175.089867 | |
| Mauku Vent | | 97 metres (318 ft) | 37°12′01″S 174°50′10″E﻿ / ﻿37.200256°S 174.836130°E﻿ / -37.200256; 174.836130 | |
| Maxted Road Cone | | 80 metres (260 ft) | 37°09′39″S 174°59′58″E﻿ / ﻿37.160775°S 174.9995420°E﻿ / -37.160775; 174.9995420 | |
| Mile Bush Hill | | 226 metres (741 ft) | 37°19′08″S 174°59′37″E﻿ / ﻿37.318996°S 174.993556°E﻿ / -37.318996; 174.993556 | |
| Morely Road Tuff Rings | | 147 metres (482 ft) | 37°13′17″S 174°46′34″E﻿ / ﻿37.221467°S 174.776110°E﻿ / -37.221467; 174.776110 | |
| Mount Calm | | 236 metres (774 ft) | 37°05′07″S 175°00′26″E﻿ / ﻿37.085180°S 175.007218°E﻿ / -37.085180; 175.007218 | |
| Onepoto (not to be confused with volcano of same name in Auckland volcanic field) | | 129 metres (423 ft) | 37°17′20″S 174°53′06″E﻿ / ﻿37.288833°S 174.884917°E﻿ / -37.288833; 174.884917 | |
| Onewhero Maar and Tuff Ring | 880 ka | 194 metres (636 ft) | 37°19′10″S 174°54′05″E﻿ / ﻿37.319393°S 174.901320°E﻿ / -37.319393; 174.901320 | |
| Otau | | 212 metres (696 ft) | 37°07′22″S 175°05′54″E﻿ / ﻿37.122826°S 175.098353°E﻿ / -37.122826; 175.098353 | |
| Paerata Tuff Ring North | | | 37°09′29″S 174°54′29″E﻿ / ﻿37.158°S 174.908°E﻿ / -37.158; 174.908 | |
| Paerata Tuff Ring South | | | 37°10′01″S 174°55′12″E﻿ / ﻿37.167°S 174.920°E﻿ / -37.167; 174.920 | |
| Pakau Stream Vent | | 16 metres (52 ft) | 37°20′23″S 174°47′03″E﻿ / ﻿37.339775°S 174.784045°E﻿ / -37.339775; 174.784045 | |
| Paparata Cone | | 319 metres (1,047 ft) | 37°10′50″S 175°03′44″E﻿ / ﻿37.180618°S 175.062109°E﻿ / -37.180618; 175.062109 | |
| Parker Lane Tuff Ring | | 10 metres (33 ft) | 37°15′19″S 174°53′47″E﻿ / ﻿37.255202°S 174.896489°E﻿ / -37.255202; 174.896489 | |
| Peach Hill | | 144 metres (472 ft) | 37°08′16″S 174°59′19″E﻿ / ﻿37.137893°S 174.988631°E﻿ / -37.137893; 174.988631 | |
| Pinnacle Hill | | 252 metres (827 ft) | 37°11′53″S 175°02′56″E﻿ / ﻿37.198°S 175.049°E﻿ / -37.198; 175.049 | |
| Pinnacle Hill Road Cone 2 | | 230 metres (750 ft) | 37°11′27″S 175°03′06″E﻿ / ﻿37.190920°S 175.051774°E﻿ / -37.190920; 175.051774 | |
| Pinnacle Hill Road Cone 3 | | 290 metres (950 ft) | 37°10′59″S 175°02′55″E﻿ / ﻿37.183158°S 175.048511°E﻿ / -37.183158; 175.048511 | |
| Pōkeno Cone | | 230 metres (750 ft) | 37°13′08″S 175°01′06″E﻿ / ﻿37.21895°S 175.018420°E﻿ / -37.21895; 175.018420 | |
| Pōkeno West Tuff Ring | | 111 metres (364 ft) | 37°15′07″S 175°01′54″E﻿ / ﻿37.252038°S 175.031749°E﻿ / -37.252038; 175.031749 |
| Ponga Road | | 292 metres (958 ft) | 37°05′58″S 174°59′50″E﻿ / ﻿37.099463°S 174.997315°E﻿ / -37.099463; 174.997315 | |
| Pukekawa | | 277 metres (909 ft) | 37°20′06″S 174°58′55″E﻿ / ﻿37.335067°S 174.982017°E﻿ / -37.335067; 174.982017 | |
| Pukekawa Tuff Ring | | 114 metres (374 ft) | 37°18′20″S 174°58′45″E﻿ / ﻿37.305464°S 174.979248°E﻿ / -37.305464; 174.979248 | |
| Pukekiwiriki (Red Hill) - not to be confused with Pukewairiki | | 210 metres (690 ft) | 37°03′50″S 175°00′01″E﻿ / ﻿37.064002°S 175.000366°E﻿ / -37.064002; 175.000366 | |
| Pukekohe North Tuff Ring | | | 37°10′34″S 174°54′07″E﻿ / ﻿37.176°S 174.902°E﻿ / -37.176; 174.902 | |
| Pukekohe East Explosion Crater | 680 ka | | 37°11′31″S 174°56′31″E﻿ / ﻿37.192°S 174.942°E﻿ / -37.192; 174.942 | |
| Pukekohe East | | 147 metres (482 ft) | 37°11′33″S 174°56′33″E﻿ / ﻿37.192402°S 174.9426098°E﻿ / -37.192402; 174.9426098 | |
| Pukekohe Hill | 550 ka | 222 metres (728 ft) | 37°13′44″S 174°53′36″E﻿ / ﻿37.228917°S 174.893246°E﻿ / -37.228917; 174.893246 | Pukekohe Hill in about 1912 |
| Puketutu | | 379 metres (1,243 ft) | 37°11′43″S 175°01′20″E﻿ / ﻿37.195386°S 175.022268°E﻿ / -37.195386; 175.022268 | |
| Pukeotahinga | | 301 metres (988 ft) | 37°20′09″S 174°51′32″E﻿ / ﻿37.335701°S 174.858921°E﻿ / -37.335701; 174.858921 | |
| Puni Domain Shield Volcano | | | 37°13′48″S 174°52′19″E﻿ / ﻿37.230°S 174.872°E﻿ / -37.230; 174.872 | |
| Rangipokia Tuff Ring | | 10 metres (33 ft) | 37°15′18″S 174°52′42″E﻿ / ﻿37.255031°S 174.878358°E﻿ / -37.255031; 174.878358 | |
| Raventhorne Maar | | 80 metres (260 ft) | 37°10′05″S 174°58′42″E﻿ / ﻿37.167953°S 174.978282°E﻿ / -37.167953; 174.978282 | |
| Razor Back Road Cone | | 172 metres (564 ft) | 37°11′52″S 174°59′58″E﻿ / ﻿37.197782°S 174.999437°E﻿ / -37.197782; 174.999437 | |
| Red Crater | | 59 metres (194 ft) | 37°13′01″S 174°56′49″E﻿ / ﻿37.217003°S 174.946902°E﻿ / -37.217003; 174.946902 | |
| Ridge Road Tuff Ring | | 116 metres (381 ft) | 37°13′33″S 174°59′23″E﻿ / ﻿37.225879°S 174.989692°E﻿ / -37.225879; 174.989692 |
| River View Road Vent | | 130 metres (430 ft) | 37°15′09″S 174°51′00″E﻿ / ﻿37.252486°S 174.850079°E﻿ / -37.252486; 174.850079 | |
| Roberts Road Vent | | 110 metres (360 ft) | 37°17′20″S 174°57′17″E﻿ / ﻿37.288912°S 174.954860°E﻿ / -37.288912; 174.954860 | |
| Rooseville Tuff Ring North | | | 37°11′31″S 174°55′01″E﻿ / ﻿37.192°S 174.917°E﻿ / -37.192; 174.917 | |
| Rooseville Tuff Ring South | | | 37°11′56″S 174°55′34″E﻿ / ﻿37.199°S 174.926°E﻿ / -37.199; 174.926 | |
| Rasumussen Road Tuff Ring | | 60 metres (200 ft) | 37°14′44″S 174°47′43″E﻿ / ﻿37.245683°S 174.795200°E﻿ / -37.245683; 174.795200 | |
| Rutherford Road Cone | | 172 metres (564 ft) | 37°11′22″S 174°57′33″E﻿ / ﻿37.189554°S 174.959220°E﻿ / -37.189554; 174.959220 | |
| Serpell Road Cone | | 230 metres (750 ft) | 37°13′42″S 175°03′16″E﻿ / ﻿37.228208°S 175.054377°E﻿ / -37.228208; 175.054377 | |
| Smeeds | | 186 metres (610 ft) | 37°18′16″S 174°59′18″E﻿ / ﻿37.304488°S 174.988195°E﻿ / -37.304488; 174.988195 | |
| Smeeds Quarry Road (Tuff Ring) | | 10 metres (33 ft) | 37°17′09″S 174°59′11″E﻿ / ﻿37.285771°S 174.986278°E﻿ / -37.285771; 174.986278 | |
| Sommerville Road Cone | | 100 metres (330 ft) | 37°12′49″S 174°47′30″E﻿ / ﻿37.213628°S 174.791774°E﻿ / -37.213628; 174.791774 | |
| Station Road Tuff Ring | | 54 metres (177 ft) | 37°12′44″S 174°48′00″E﻿ / ﻿37.212282°S 174.799945°E﻿ / -37.212282; 174.799945 | |
| Tauranganu | | 228 metres (748 ft) | 37°20′32″S 174°48′34″E﻿ / ﻿37.342163°S 174.809535°E﻿ / -37.342163; 174.809535 | |
| Te Kohanga Tuff Ring | | | 37°18′35″S 174°50′04″E﻿ / ﻿37.309673°S 174.834508°E﻿ / -37.309673; 174.834508 | |
| Tikorangi | | 122 metres (400 ft) | 37°18′28″S 174°50′59″E﻿ / ﻿37.30785°S 174.849652°E﻿ / -37.30785; 174.849652 | |
| Totara | | 335 metres (1,099 ft) | 37°09′42″S 175°01′21″E﻿ / ﻿37.161564°S 175.022577°E﻿ / -37.161564; 175.022577 | |
| Tuakau Vent | | 122 metres (400 ft) | 37°15′55″S 174°56′05″E﻿ / ﻿37.265248°S 174.934825°E﻿ / -37.265248; 174.934825 | |
| Waiuku Vent | | 111 metres (364 ft) | 37°15′08″S 174°46′11″E﻿ / ﻿37.252192°S 174.769786°E﻿ / -37.252192; 174.769786 | |
| Waiuku Parastic Vent | | 45 metres (148 ft) | 37°16′10″S 174°45′31″E﻿ / ﻿37.269380°S 174.758521°E﻿ / -37.269380; 174.758521 | |
| Whangarata Vent | | 160 metres (520 ft) | 37°16′36″S 174°58′21″E﻿ / ﻿37.276726°S 174.972493°E﻿ / -37.276726; 174.972493 | |