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Nelson is a city on the eastern shores of Tasman Bay / Te Tai-o-Aorere. Nelson is the oldest city in the South Island and the second-oldest settled city in New Zealand – it was established in 1841 and became a city by royal charter in 1858.
An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks.
Dunite is an igneous, plutonic rock, of ultramafic composition, with coarse-grained or phaneritic texture. The mineral assemblage is greater than 90% olivine, with minor amounts of other minerals such as pyroxene, chromite, magnetite, and pyrope. Dunite is the olivine-rich end-member of the peridotite group of mantle-derived rocks. Dunite and other peridotite rocks are considered the major constituents of the Earth's mantle above a depth of about 400 kilometers. Dunite is rarely found within continental rocks, but where it is found, it typically occurs at the base of ophiolite sequences where slabs of mantle rock from a subduction zone have been thrust onto continental crust by obduction during continental or island arc collisions (orogeny). It is also found in alpine peridotite massifs that represent slivers of sub-continental mantle exposed during collisional orogeny. Dunite typically undergoes retrograde metamorphism in near-surface environments and is altered to serpentinite and soapstone.
Christian Gottlieb Ferdinand Ritter von Hochstetter was a German-Austrian geologist.
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, a unitary authority, which sits at Richmond, with community boards serving outlying communities in Motueka and Golden Bay / Mohua. The city of Nelson has its own unitary authority separate from Tasman District, and together they comprise a single region in some contexts, but not for local government functions or resource management (planning) functions.
The Riuwaka River, formerly known as the Riwaka River, is located in the Nelson region in the northwest of New Zealand's South Island. It flows for 20 kilometres, entering Tasman Bay / Te Tai-o-Aorere close to the town of Riwaka, 10 kilometres north of Motueka.
Tasman Bay / Te Tai-o-Aorere, originally known as Blind Bay, is a large V-shaped bay at the north end of New Zealand's South Island. Located in the centre of the island's northern coast, it stretches along 120 kilometres (75 mi) of coastline and is 70 kilometres (43 mi) across at its widest point. It is an arm of the Tasman Sea, lying on the western approach to Cook Strait.
The Lud River is a river of the Nelson Region of New Zealand's South Island. It flows north from a ridge 10 kilometres (6 mi) east of Nelson city centre, reaching the Wakapuaka River close to the latters outfall into Delaware Bay, an indentation in the eastern shore of Tasman Bay / Te Tai-o-Aorere.
The Miner River is a river of the Tasman Region of New Zealand's South Island. It rises in hills 10 kilometres (6 mi) south of Nelson city centre close to the southern end of the Bryant Range, flowing west to joining with the Roding River 4 kilometres (2.5 mi) south of Richmond.
The Olivine River is a river in northern Fiordland, New Zealand. It rises north of the Cow Saddle and flows north, then north-west over Olivine Falls to become a tributary of the Pyke River near Olivine Hut. The Five Passes hiking (Tramping) trail passes through the upper river near Cow Saddle. The Dun Mountain Ophiolite Belt which is rich in the mineral olivine outcrops extensively in the Olivine River and its tributaries.
The Whangamoa River is a river of the Nelson Region of New Zealand's South Island. It flows generally northeast from its origins in the northern Bryant Range 15 kilometres (9 mi) northeast of Nelson city centre to reach Tasman Bay / Te Tai-o-Aorere close to the northeastern end of Delaware Bay.
The Tasman Region, and the small adjoining Nelson Region, form one of the more geologically interesting regions of New Zealand. It contains the oldest rocks of anywhere on New Zealand's main islands. It contains all the main terranes that make up New Zealand's basement. These basement rocks include Ultramafic rocks, such as Serpentine and Dunite, and valuable minerals, such as Gold. The Nelson Region is bordered to the south by the Alpine Fault, the main fault forming the boundary between the Pacific Plate and the Indo-Australian Plate, that generated the Southern Alps.
Bronte, a locality in the Tasman Region of New Zealand, lies between Richmond and Mapua.
The Bryant Range is a range of low mountains in the northern South Island of New Zealand. They form part of the boundary of the Nelson and Tasman Districts with Marlborough Region, as well as forming the western boundary of Mount Richmond Forest Park The range is traversed by State Highway 6 at the Rai Saddle close to its northern end.
The Dun Mountain-Maitai Terrane comprises the Dun Mountain Ophiolite Belt, Maitai Group and Patuki Mélange. The Dun Mountain Ophiolite is an ophiolite of Permian age located in New Zealand's South Island. Prehistorically this ophiolite was quarried by Māori for both metasomatized argillite and pounamu (jade) which was used in the production of tools and jewellery.
Rodingite is a metasomatic rock composed of grossular-andradite garnet, calcic pyroxene, vesuvianite, epidote and scapolite. Rodingites are common where mafic rocks are in proximity to serpentinized ultramafic rocks. The mafic rocks are altered by high pH, Ca2+ and OH− fluids, which are a byproduct of the serpentinization process, and become rodingites. The mineral content of rodingites is highly variable, their high calcium, low silicon and environment of formation being their defining characteristic. Rodingites are common in ophiolites, serpentinite mélanges, ocean floor peridotites and eclogite massifs. Rodingite was first named from outcrops of the Dun Mountain Ophiolite Belt in the Roding River, Nelson, New Zealand.
Dun Mountain is a mountain in the Richmond Range near the city of Nelson in the Tasman District of New Zealand's South Island. It is located between the catchments of the Pelorus, Maitai and Roding Rivers. The mountain is named for its brown (Dun) colour. The colour is caused by the ultramafic rock which forms the mountain. Ultramafic Rock weathers to this colour and plant growth is also stunted due to the soils high heavy metal content. The ultramafic rock formed in the earth's mantle in the Permian and is now part of the Dun Mountain Ophiolite Belt.
The Takaka Terrane is a Paleozoic terrane that outcrops in the South Island of New Zealand. It is most extensively exposed within the Kahurangi National Park in the Tasman District. The terrane is mostly made up of marble and volcanic rocks but is highly variable in composition. It ranges in age from mid-Cambrian to Devonian time, 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 Rock" a glacial 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.
Pounamu or greenstone are terms for several types of hard and durable stone found in southern New Zealand. They are highly valued in New Zealand, and carvings made from pounamu play an important role in Māori culture.
References
- ↑ Johnston, M. R. (2007). "Nineteenth-century observations of the Dun Mountain Ophiolite Belt, Nelson, New Zealand and trans-Tasman correlations,". Geological Society, London, Special Publications. 287: 375–387. Bibcode:2007GSLSP.287..375J. doi:10.1144/sp287.27.