26th International Applied Geochemistry
Symposium Incorporating the 35th New Zealand
Geothermal Workshop, 18-21 November 2013,
Rotorua New Zealand    

New Zealand

New Zealand is located in the South pacific between the Pacific Ocean and the Tasman Sea, between latitudes 35o and 45o south, approximately 2000 km to the east of Australia. New Zealand has a temperate climate with relatively high rainfall, green rolling hills in the North Island and majestic mountains, lakes and fiords in the South Island. The spectacular scenery, friendly people and excellent facilities make New Zealand one of the World’s top tourist destinations.

New Zealand is a politically stable country governed under Westminster-style democracy, with free elections held every three years. It is a safe country, demonstrated by the fact that police on patrol do not carry firearms.

The quality of goods and services – as well as food and beverage within New Zealand – is exceptionally high, with New Zealand wines, dairy produce, meat and horticultural products having a well deserved reputation for excellence.

 

NEW ZEALAND KEY FACTS

Land area

270,500 km2

Population

4 million

Capital city

Wellington (pop. 480,000)

Largest city

Auckland (pop. 1,294,000)

Highest mountain

Mount Cook - 3,764 m above sea level

Longest river

Waikato River - 425 km

Largest lake

Lake Taupo - 606 km2

Time zone

12 hours ahead of GMT
(plus 1 hour during summer)

Land use

52.4% pasture and arable land, 27.6% forests, 18.6% other

Languages

English, Maori, sign

 

 

 

 

 

Geology

NZ geology mapFor a landmass of only 270,500 km2, New Zealand has a varied and complex geology. These features are a result of an active tectonic history related to a position on a plate boundary or continental margin throughout New Zealand's 600 million year geological record. This tectonism continues today with New Zealand's location on the boundary between the Pacific and Indian-Australian plates, along the "Pacific Ring of Fire" belt of volcanic and earthquake activity. Its dynamic geological past has endowed New Zealand with spectacular scenery and a wide variety of natural resources.
The rocks of New Zealand can be grouped into three elements which correspond to specific tectonic cycles in the geological record:

  • Western Province (Paleozoic)
  • Eastern Province (Paleozoic to Cretaceous)
  • younger sedimentary and volcanic cover rocks (Cretaceous to Cenozoic).

The Western and Eastern provinces are separated by the Median Batholith and were formed on or near the margin of the ancient Gondwana supercontinent, whereas the younger rocks developed after the separation of New Zealand from Gondwana about 82 million years ago in the Cretaceous. Transcurrent displacement of 480 km along the Alpine Fault has separated the Western and Eastern provinces into northern South Island and southeast South Island segments.

 

1996 Ruapehu eruption viewed from the east

 

Mineral, coal and petroleum resources

Gold is the most important metal produced, but New Zealand also produces silver, coal, ironsand, aggregate, limestone, clay, dolomite, pumice, salt, serpentinite, and zeolite. In addition, there are resources or potential for deposits of platinum, titanium (ilmenite mineral sands), sulphur, phosphate, silica and mercury. There is also submarine sulphide mineralisation in New Zealand's offshore Exclusive Economic Zone.

Gold is produced from four hard rock mines and a large number of placer mines. Ironsand is produced from two placer mines and used in the local steel industry and for export. Additionally, a wide range of industrial minerals are also mined including the World’s most expensive clay – halloysite – for use in high quality ceramics.

Coal has been an important energy source in New Zealand since the late nineteenth century. Coal mining was established in all of the major coalfields during the last half of the nineteenth century, with production increasing rapidly in the late nineteenth century and into the early 1900s. Total cumulative production from all New Zealand coalfields has been about 260 Mt. Over the last 20 years, the West Coast and Waikato regions have been the largest producers.

Bituminous coal is produced on the West Coast, mainly for export, and sub-bituminous coal is produced in Waikato, West Coast, Central Otago and Southland, mainly for domestic consumption.   Lignite resources in Southland and Otago of about 10 billon tonnes have been worked on a small scale, but investigations continue into large-scale uses such as making liquid fuels and petrochemicals.

Oil and gas exploration commenced in the late 1800s. Exploration is currently concentrated in the Taranaki region where there are both on-shore and off-shore fields.  Petroleum exploration is currently active in many other areas, including the east coast of the North Island, the Raukumara Basin north of East Cape, the west coast of the South Island, Canterbury and the Great South Basin southeast of Dunedin. Large sedimentary basins may underlie up to 20% of New Zealand’s territory including the offshore Exclusive Economic Zone. Oil production (c. 21 million barrels/year) is entirely from the Taranaki area and is currently New Zealand’s third largest export earner behind dairy and meat.

 

New Zealand mineral resources and production

 

 

300°C black smoker chimney, Brothers Volcano, Kermadec Arc

 

Considerable research and exploration attention has recently focused on sea floor massive sulphide systems of the Kermadec Arc, northeast of the North Island. New Zealand has led the world in research on these arc systems that have potential to host major resources of base and precious metals. Exploration along the arc has shown that over its ~1300 km length, some 77% of the submarine volcanic centres are presently hydrothermally active, with massive sulphides having been recovered to date from three volcanic centres.

 

Hydrothermal venting on the sea floor is associated with the active sites on several undersea volcanoes along the Kermadec Arc

 

 

 

Geothermal resources

Geothermal power stations contribute about 15% of New Zealand’s electricity needs. Geochemistry has played a pivotal role in the exploration and development of New Zealand’s geothermal systems.

 

Map showing geothermal fields in New Zealand

Geothermal fields in the Taupo Volcanic Zone of New Zealand

Geothermal systems and hot springs

 

Wairakei geothermal field, New Zealand’s first producer of electricity from geothermal energy