|
Mount Manaia
Mount Manaia is a dominant landmark approximately 30 kilometres southeast of Whangārei city on the Whangārei Heads peninsula. Standing 420 metres, the summit offers outstanding views of the Marsden Point Oil Refinery, Bream Bay and the Hauraki Gulf to the south, Whangārei Harbour to the west and the Poor Knights Islands and Northland coast to the north. Mt Manaia - along with Mt Lion, Bream Head and the Hen and Chicken Islands, are the scattered remnants of andesite, volcanic intusions that erupted with force 16 to 22 million years ago during the early Miocene. They are part of a stratovolcano that extended to the Hen and Chickens. Its jagged outline is similar to that of its neighbours and other volcanic outcrops in Northland that erupted in a similar period. Today blanketed by native bush, Manaia's jagged peaks and steep bluffs are protected within a Department of Conservation reserve which features a well-maintained 1½ hour track to the summit. Photo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taurikura
Taurikura is a small, rural township in the Whangarei District, approximately south east of Whangārei city in Northland, New Zealand. The town is located on the shores of Calliope Bay at the base of Mount Manaia which, along with Bream Head and the Hen Island, collectively form the ancient remnants of a very large andesitic volcano.Geological Society of New Zealand Annual Conference 2–5 December 2002 Features of Taurikura include a Baptist-owned camp and a general store. The local school, Whangarei Heads School, is the second oldest school in New Zealand still operating on its original site. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial planet, rocky planet or natural satellite, moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of volcanism on Venus, Venus, which cover ~80% of the surface, are basaltic; the lunar mare, lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Barrier Island
Great Barrier Island ( mi, Aotea) lies in the outer Hauraki Gulf, New Zealand, north-east of central Auckland. With an area of it is the sixth-largest island of New Zealand and fourth-largest in the main chain. Its highest point, Mount Hobson, is above sea level.Great Barrier Island Aotea page on the DOC website (from the . Accessed 2008-06-04.) The is the [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Department Of Conservation (New Zealand)
The Department of Conservation (DOC; Māori: ''Te Papa Atawhai'') is the public service department of New Zealand charged with the conservation of New Zealand's natural and historical heritage. An advisory body, the New Zealand Conservation Authority (NZCA) is provided to advise DOC and its ministers. In addition there are 15 conservation boards for different areas around the country that provide for interaction between DOC and the public. Function Overview The department was formed on 1 April 1987, as one of several reforms of the public service, when the ''Conservation Act 1987'' was passed to integrate some functions of the Department of Lands and Survey, the Forest Service and the Wildlife Service. This act also set out the majority of the department's responsibilities and roles. As a consequence of Conservation Act all Crown land in New Zealand designated for conservation and protection became managed by the Department of Conservation. This is about 30% of New Z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratovolcano
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and hardens before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma. Extensive felsic lava flows are uncommon, but have travelled as far as . Stratovolcanoes are sometimes called composite volcanoes because of their composite stratified structure, built up from sequential outpourings of erupted materials. They are among the most common types of volcanoes, in contrast to the less common shield volca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hen And Chicken Islands
The Hen and Chicken Islands (usually known collectively as the ''Hen and Chickens'') lie to the east of the North Auckland Peninsula off the coast of northern New Zealand. They lie east of Bream Head and south-east of Whangarei with a total area of . History Approximately 18,000 years ago during the Last Glacial Maximum when sea levels were over 100 metres lower than present day levels, the islands were hilly features surrounded by a vast coastal plain. Sea levels began to rise 7,000 years ago, after which the islands separated from the rest of New Zealand. These islands were given their European name by Captain James Cook, who first sighted them on 25 November 1769. It has been suggested that the name was inspired by an old name for the star cluster usually known as the Pleiades. Originally owned by the Māori Ngā Puhi iwi, they were sold to the New Zealand Government in 1883. The islands were made a scenic reserve in 1908 owing to the rarity of their flora and fau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bream Head
Bream Head is a promontory on the east coast of Northland in the North Island of New Zealand. Located at the end of a 30 kilometre-long peninsula, the head juts into the Pacific Ocean to the southeast of Whangārei. The Hen and Chicken Islands are located off the headland at a distance of 12 kilometres. Bream Head features a prominent bluff 490 metres in height, the remains of a Miocene andesitic volcano. It forms the northern extremity of Bream Bay, and guards the entrance to Whangārei Harbour, a natural inlet extending to the northwest. The Marsden Point Oil Refinery Marsden Point Oil Refinery is a 96,000 BPD refinery located at Marsden Point, Whangarei, Northland, New Zealand. It is the only oil refinery in New Zealand, and is operated by Refining NZ. The point was named after Samuel Marsden. The regional sur ... is located on the opposing shore of the harbour five kilometres to the west. To Bream Head's immediate North is a long sandy beach called Ocean Beach. Gallery ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intrusive Rock
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form ''Igneous intrusion, intrusions'', such as batholiths, dike (geology), dikes, Sill (geology), sills, laccoliths, and volcanic necks.Intrusive RocksIntrusive rocks accessdate: March 27, 2017.Igneous intrusive rocks, accessdate: March 27, 2017.Britannica.comintrusive rock , geology , Britannica.com accessdate: March 27, 2017. Intrusion is one of the two ways igneous rock can form. The other is extrusive rock, extrusion, such as a Types of volcanic eruptions, volcanic eruption or similar event. An intrusion is any body of intrusive igneous rock, formed from magma that cools and solidifies within the crust of the planet. In contrast, an ''extrusion'' consists of extrusive rock, formed above the surface of the crust. Some geologists use the term plutonic rock synonymously with intrusive rock, but other geologists subdivide intrusive rock, by crystal size, into coarse-grai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ignimbrite
Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrounding atmosphere. New Zealand geologist Patrick Marshall (1869-1950) coined the term ''ignimbrite'' from the Latin ''igni-'' [fire] and ''imbri-'' [rain]. Ignimbrites are made of a very poorly sorted mixture of volcanic ash (or tuff when Lithification, lithified) and pumice lapilli, commonly with scattered lithic fragments. The ash is composed of glass shards and crystal fragments. Ignimbrites may be loose and unconsolidated, or lithified (solidified) rock called lapilli-tuff. Near the volcanic source, ignimbrites often contain thick accumulations of lithic blocks, and distally, many show meter-thick accumulations of rounded cobbles of pumice. Ignimbrites may be white, grey, pink, beige, brown, or black depending on their composition and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent to granite. Rhyolitic magma is extremely viscous, due to its high silica content. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations. Rhyolitic tuff has been extensively used for construction. Obsidian, which is rhyolitic volcanic glass, has been used for tools from prehistoric times to the present day because it can be shaped to an extremely sharp edge. Rhyolitic pumice finds use as an abrasive, in concrete, and as a soil amendment. Description Rhyolite i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dacite
Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz. Dacite is relatively common, occurring in many tectonic settings. It is associated with andesite and rhyolite as part of the subalkaline volcanic rock, subalkaline tholeiite, tholeiitic and calc-alkaline magma series. Composition Dacite consists mostly of plagioclase feldspar and quartz with biotite, hornblende, and pyroxene (augite or enstatite). The quartz appears as rounded, corroded phenocrysts, or as an element of the ground-mass. The plagioclase in dacite ranges from oligoclase to andesine and labradorite. Sanidine occurs, although in small proportions, in some dacites, and when abundant gives rise to rocks that form rhyodacite, transitions to the rhyolites. The rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
