Geology of New Zealand

The geological conditions in New Zealand are influenced to a considerable extent by the tectonic activity of the Pacific and the Australian plate. The meeting of the two plates, initially diverging, converging later, shaped the country with its two main islands over millions of years and is still doing so today. The external manifestations of these processes can be observed with mountain folds, volcanism, earthquakes, and numerous geothermal activity. Especially in the North Island leads the meeting of the two boards to increased volcanic activity, with some of the most active volcanoes in the world are located in the center of the North Island and north of it and concentrate in the Taupo Volcanic Zone ( TVZ ). New Zealand is among the countries of the Pacific, directly on the Pacific Ring of Fire (English: Pacific Ring of Fire) lie, a volcanic belt that encircles the Pacific Ocean.

5.1 coal
5.2 Gold
5.3 silver
5.4 platinum metals
5.5 Heavy mineral sands
5.6 Other Mineral Raw Materials

Geological Review

Before about 280 million years ago was the land mass that is assigned to New Zealand today, to the north-eastern part of the coast of the supercontinent Gondwana upstream. Under the pressure of westward migrating Pacific Plate is a mountainous strip began to form and to rise from the sea about 200 million years ago in the sea bed. With an eastward drift of the survey was split off about 70 million years ago by the ancient continent and let the lying below sea continent Zealandia and the Tasman Sea arise. The already living on the mountain strip plants and animals developed from this point on independent further and thus became endemic.

Before about 60 million years ago the land mass of New Zealand was far greater than today. But constant erosion processes could flatten the mountains to hills and plains. Through continuous land erosion of the sea moved the coastline inland. Tectonic processes turned the southern part of the country faster counterclockwise could happen than the northern part. The resulting two main islands laid the basis for the division of New Zealand. About 35 million years later, around 60 % of today's land area was under water. The more progressive and different fast rotation of the two main islands was between the Pacific plate and the Australian plate a grave breach ( Rift ) arise, the Alpine Fault. To this warp around the North and the South Island moved further left-handed and set New Zealand on a northeast-trending axis. In addition to the Alpine Fault was formed south of this, the Puysegur Trench and the northern course of the Kermadec Trench and Trench Hikuranki.

In the North Island, where the Pacific plate today pushes beneath the Australian plate, formed volcanically active areas and in the South Island, where the Pacific plate moves southwestward along the Australian plate, formed by folds in the Southern Alps.

Geology

The geological structure of New Zealand can be assigned from its genesis forth roughly three geological cycles:

The early to middle Paleozoic, in the western area of New Zealand was formed.
The late Paleozoic through to the Early Cretaceous, in which the eastern part was.
The Late Cretaceous to Cenozoic in the inside, in the sediments and rocks of volcanic origin arose.

One of the oldest known sedimentary outcrops of New Zealand, about 100 km north-west of Nelson in Takaka - layer complex former island arcs, is formed from mittelkambrischen sedimentary sequences of the junction formation mainly of turbiditic sandstones, Schluffgesteinen and conglomerates as well as some basaltic and andesitic units. The Trilobitenversteinerungen contained in the layers of Haupiri group are the oldest fossils of New Zealand.

A more detailed classification of the geological structure of New Zealand, the following card with the associated table.

Geological regions

The main islands of New Zealand are determined by a mountainous relief, which runs in a northeast-southwest orientation of the two islands and thereby represents as part of an extensive mountain system, which encloses the entire Pacific region along the Pacific Ring of Fire. However, the two islands have distinct differences in relief. These differences result from the different acting tectonic processes that have shaped New Zealand.

North Island

The mountains of the North Island are determined by tectonics and volcanism, with flatter regions got their imprints by sediment deposits. The regions are as follows:

Along the main fault system that runs from south to north by the North Island and is represented by the Wellington Fault, Mohaka Fault, Ruahine Fault and then almost running parallel split by the Waiohau Fault, Whakatane Fault, Waimana Fault, has become one for the North Island significant mountain region formed. Greywacke is here in the Rimutara Range, Tararua Range, Ruahine Range, Kaweka Range, Range Huiarau, Ikawhenua Range, Range Raukumara the defining rock.
The Taupo Volcanic Zone ( TVZ ), some 80 km north- north east from the submarine Whakatane volcano of White Iceland, in direction southsouthwest to Mount Ruapehu extends over a length of 350 km and initially to more than 100 km was wide, represents the volcanically active part of New Zealand dar. meantime divided into three categories, the Taupo Volcanic Zone has over the so-called " old zone " (millions of years ago from 2 to 0.34 ), about the " young zone" ( 0.34 million years ago to 65 thousand years ago) to the called in English " modern zone " ( 65 thousand years ago to the present) in width expansion continually reduced. Today, the substantial distortions and the most active volcanic areas are located in a band of up to 50 km. Several large lakes such as Lake Taupo, Lake Rotorua and Lake Tarawera, and the largest volcanoes, Mount Ruapehu with its 2,797 m, Mount Ngauruhoe with 2,291 m and 1,967 m Mount Tongariro with are there on a line. The continental crust measures in the Taupo Volcanic Zone to the 15 km thick, as opposed to the usual 35 km beneath the plains.
The Central Volcanic Plateau is a central plateau in the middle of the North Island, which includes the southern part of the Taupo Volcanic Zone. Noteworthy here is the Rangipo Desert, a barren desert-like landscape with sand dunes and bizarre run-off, which makes it the layer structure visible. Rangipo located in the southeastern part of the plateau.
The eastern part of the North Island with the regions, Wairarapa, Hawke 's Bay, Gisborne and Eastland, and the western part with the regions Taranaki to North Iceland Volcanic Plateau and the western part of the Waikato region all the way up made just before Auckland flat lagerndem sandstone of the Cretaceous and deposits from the Miocene and the Pliocene. Alluvium can be found among others in the lower river landscapes of the largest rivers, Manawatu River and the Waikato River and in the coastal lowlands of the Hawke Bay.
The area around Mount Taranaki is of volcanic origin and is therefore in the surrounding sediment certain regions an exception.

South Island

The South Island is mostly, but mainly dominated by mountain folds and glaciation in the western part of the island. The surface in shallower regions consists mainly of sediments. The regions are as follows:

The mountain range that runs from north of the North Island, continuing along the South Island, has alpine character and culminating in the glacier area around the highest mountain in the country around Mount Cook. Mesozoic gneiss, mica schist and greywacke are involved mainly in the lithology of the New Zealand Alps.
A narrow strip on the west coast of Haast way up to the area around Nelson is dominated by sedimentary rocks, where the northern part is traversed by regions where granite is the dominant rock underground. However, a north to the Golden Bay extending area is of volcanic origin and interspersed with deposits of limestone.
East of the Southern Alps to the edge of the Canterbury Plains of the subsoil consists mainly of greywacke, with a narrow band down from mica schists spreads to the Otago region and there represent the prevailing rock.
The Canterbury Plains in the middle eastern coastal region consists entirely of sediments.
The few areas of purely volcanic origin lying on the South Island on the Banks Peninsula, near Christchurch and further south the city of Dunedin comprising the Otago Peninsula and the Otago Harbour.
Fiordland, in the far southwest of the South Island, however, is mainly composed of metamorphic rocks and, with its rugged coastline and to over 2,700 m high mountains, the southern extension of the Southern Alps dar.

Geological outcrop

In the recording work on the Dun Mountain in Nelson Ferdinand von Hochstetter explored a time not yet classified rock and named it after the type locality dunite. The first scientific description of the rock, he published in 1864.

Mineral resources

New Zealand is rich in mineral resources. Especially metals, such as gold, silver and platinum group metals, as well as coal, various economically important minerals exist in large quantities and are degraded to economic conditions. Here are the most important ones:

Coal

New Zealand has extensive lignite deposits, which are found mainly in the Waikato region of the North Island and the Taranaki region and on the West Coast, Otago and south of the South Island. The resource is estimated at about 15 billion tons, which spread 80 % of the deposits in the South Island. The brown coal of the South Island studies is the result, among other things as a raw material for producing fuels, briquettes and fertilizers in large petrochemicals plants.

Gold

With other countries in which gold is produced Compared world, the flow of gold in New Zealand with around 13.5 tonnes in 2009 is comparatively small. But part of gold, along with silver, the most important raw materials in New Zealand that are promoted.

Gold deposits are present on both islands, where they can come from four different reservoir situations:

Mesothermal quartz veins in greywacke, originated in the Paleozoic,
Mesothermal quartz veins in schist, formed in the Mesozoic,
Epithermal quartz veins in volcanic rock, originated in the Cenozoic,
Soaps in gravel or sand, also originated in the Cenozoic.

Other mineralization of gold are found in copper and in hydrothermal deposits, but have based on their occurrence not of great importance.

Larger gold deposits are located on the Coromandel Peninsula, in the Taupo Volcanic Zone on the West Coast and in Otago, where the largest gold mine in the country, the Macraes gold mine is located. Overall, it is mined in 50 different places in the country for gold. In 2006 it was estimated that the total gold deposits in New Zealand at around 1,230 tonnes.

Silver

The mining of silver is a by- product of gold mining in New Zealand. Gold and silver occur mostly at their sites on together. Thus, the classification of the four types of deposits for gold (see above) in the same way for silver is considered. In 2009, about 14.3 tons of silver tendency were not won in New Zealand, falling. Your peak production reached in 2005 with 43 tons.

Almost all of the silver recovered in New Zealand comes from the second largest mine in the country, the Martha mine, along with the 2 km away Favona mine. The proportion of silver to the total funding is there together around 85 %. The rest is gold.

Platinum metals

Located in the Longwood Range, approximately 40 km north- west of Invercargill, the New Zealand government suspected deposits of platinum metals ( ruthenium, rhodium, palladium, osmium, iridium, and platinum) to the value of NZ $ 2 billion. It is estimated to find ( about 31 tons ) of rare metals in a 12 times 32 km large area up to 1 million troy ounces.

Green Hills, a few miles north of Bluff, situated on an area of 14 km2 another important locality Represents the Anglem field on Stewart Iceland is 35 times 14 km across and near Riwaka extends a band over 45 km in length and up to 3 km width. The 400 km2 by far the largest area where PGMs are found, is the region around Rotoroa.

Heavy mineral sands

Described already in 1839 Ernst Dieffenbach, hired by London's New Zealand Company, the deposits of titanium mineral-rich sand on the coast of Taranaki. 1841 this was confirmed by the head of the New Zealand expedition Plymouth Company of New Zealand, George Cutfield again. A year later, it sent Frederic Alonzo Carrington, a surveyor of the New Zealand Company, samples of so-called iron sand to England this to get tested for its usefulness for iron production. The run on these commodities began.

Heavy mineral sand in the form of the iron sand is found in many western coastlines of the two main islands. Probably the largest deposits exist on the 480 km long coastline of the North Island from Kaipara Harbour down to Whanganui. The black material, eroded volcanic rock of Mount Taranaki and the North Iceland Volcanic Plateau, was once carried by the rivers of the Rangitikei River up to the Waikato River into the sea and deposited in the shelf zone of the coast.

Founded in September 2007 Trans -Tasman Resources Limited ( TTR) was given for two before that Coastal Sea areas covering an area of almost 10,000 km2 to promote the authorization iron sand. Studies have shown this area that about 4.5 billion tons can be mined economically with an iron content of 6.23 %. Furthermore, the ore contains 0.7 % vanadium ( V) oxide and owns shares of titanium ( IV) oxide The occurrences seem to be so gigantic that the Taranaki Daily News already coined by the company TTR concept of "ocean of iron ore " ( German: Iron Ore Ocean) had disclosed to the public.

In 2009, about 2 million tons were supported by iron sand throughout New Zealand. The majority came to the time of Barry Town and Westport, located on the west coast of the South Island. The sand that is mined there, is in Westport to 4.5 % from ilmenite and in Barrytown to 13.8%. It is suspected occurrence in the order of 122 million tonnes, or 50 million tons.

Over the range of the total deposits of heavy mineral sands in New Zealand, there are no ideas.

Other Mineral Raw Materials

More nichterzliche raw materials, which are industrially mined and utilized the alphabetical order by: bentonite, pumice, diatomite, dolomite, halloysite - 7 Å, limestone, perlite, silica, various clays and zeolites.

Known geologists in New Zealand

Ernst Dieffenbach (1811-1855), was a German physician, geologist and naturalist, who has for two years lived and researched in New Zealand and on its publication " Travels in New Zealand" is also reflected in the geology of New Zealand has been earned.
Julius von Haast (1822-1887), was German - New Zealand geologist and naturalist, professor of geology at the Canterbury College.
Ferdinand von Hochstetter (1829-1884), was an Austrian geologist and started on behalf of the then governor with the geological mapping of New Zealand.
James Hector (1834-1907), was Scottish- New Zealand physician, geologist, researcher, leader of various institutes and New Zealand from 1885 to 1903 Chancellor of the University of New Zealand.
Frederick Wollaston Hutton (1836-1905), was an English -born naturalist, who was appointed as the first Director of the Otago School of Mines and served as curator of the Otago Museum. He has become known to evolutionary theory through the systematic description of fossils and by working.
Alexander McKay (1841-1917), was a schottischstämmiger geologist who dealt with fault zones in New Zealand and an extensive collection of fossil pieces of evidence left behind.
James Park (1857-1946), was a schottischstämmiger geologist, director of the Thames School of Mines was and merits earned in the mining geology of New Zealand.
Patrick Marshall (1869-1950), was an English -born geologist who dealt with the study of volcanic rocks in the Pacific. From him the terms ignimbrite and Andesitlinie come.
Charles Andrew Cotton (1885-1970), was an internationally recognized scientist in the field of geomorphology.
Francis John Turner (1904-1985), was petrologist and merits acquired in the study of metamorphic rocks.
Harold Wellman (1909-1999), was an expert in the field of plate tectonics and a member of the Royal Society of New Zealand.
William Sefton Fyfe (1927-2013), is an emeritus professor of geology, studied at the University of Otago, has taught at universities in the United States, England and most recently in Canada later.

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