The Takaka Terrane is a

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured" to crust lying on another plate. The crustal block or fragment preserves its ow ...

that outcrops in the

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasma ...

of New Zealand. It is most extensively exposed within the

Kahurangi National Park Kahurangi National Park in the northwest of the South Island of New Zealand is the second largest of the thirteen national parks of New Zealand. It was gazetted in 1996 and covers , ranging to near Golden Bay in the north. Much of what was t ...

in the

Tasman District Tasman District () is a local government district in the northwest of the South Island of New Zealand. It borders the Canterbury Region, West Coast Region, Marlborough Region and Nelson City. It is administered by the Tasman District Council, ...

. The terrane is mostly made up of

marble Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorpho ...

and volcanic rocks but is highly variable in composition. It ranges in age from mid-

Cambrian The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ag ...

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, w ...

time (510–400 Ma), including New Zealand's oldest rocks, which are found in the Cobb Valley in north-west Nelson. The Cobb Valley is also the location of "

Trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the ...

Rock" a

glacial A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...

dropstone made from the moulted exoskeletons of trilobites. Asbestos was mined in the Cobb Valley from the Takaka Terrene between the late 1880s and 1917. The Takaka Terrane is highly deformed and has been intruded by many

batholiths A batholith () is a large mass of intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, such ...

Description

The Takaka Terrane has two main igneous units, the arc-related Devil River Volcanics Group (

Middle Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek (d ...

Late Cambrian Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

) and the rift‐related

Gendarme Dolerite Wrong info! --> A gendarmerie () is a military force with law enforcement duties among the civilian population. The term ''gendarme'' () is derived from the medieval French expression ', which translates to "men-at-arms" (literally, " ...

(latest Cambrian to Early Ordovician age). The Devil River Volcanics Group sediments contain

trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the ...

brachiopod Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, ...

s and

conodont Conodonts ( Greek ''kōnos'', " cone", + ''odont'', " tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, w ...

s. Sedimentary units in the Takaka Terrane (

Haupiri Group Haupiri is a locality in the West Coast region of New Zealand's South Island. Greymouth lies to the west. The Ahaura and Haupiri Rivers run through the area. The population of the Haupiri statistical district, which covers a much larger area than ...

and Junction Formation rocks) likely formed in a

back-arc basin A back-arc basin is a type of geologic basin, found at some convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found in the western Pacific Ocean. Most ...

. The distinctive Arthur Marble from Takaka Hill and Mount Arthur is of

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. ...

age. It has been speculated that the Takaka Terrane is equivalent to rocks in

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

, Australia and was separated from them with the opening of the

Tasman Sea The Tasman Sea ( Māori: ''Te Tai-o-Rēhua'', ) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer ...

. The Arthur Marble has been chemically

weathered ''Weathered'' is the third studio album by American rock band Creed, released on November 20, 2001. It was the last Creed album to be released until '' Full Circle'' came out in October 2009, with Creed disbanding in June 2004. It is the only C ...

by rain and groundwater due to its high calcium carbonate content forming a karst

geomorphology Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or ...

. This has led to the formation of extensive cave systems like

Harwood Hole Harwoods Hole is a cave system located in the northwest of the South Island of New Zealand, in the Abel Tasman National Park. At , it is New Zealand's deepest vertical shaft. It was first explored in 1958, long after it was discovered. Formatio ...

and the Riuwaka Resurgence.

References

{{coord missing, New Zealand Terranes Geology of New Zealand Paleozoic Oceania Landforms of the Tasman District

Description

See also

References