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Manuherikia Group
The Manuherikia Group is a fluvial- lacustrine sedimentary fill in the Central Otago area of New Zealand, at the site of the prehistoric Lake Manuherikia. The area consists of a valley and ridge topography, with a series of schist-greywacke mountains at roughly ninety degrees to each other. The Manuherika Group occurs in the current basins, and occasionally on the mountains themselves. History One of the earliest geologists to work in the area, McKay, understood that the Manuherikia Group was probably originally continuous. Although some workers came to believe the sediments were deposited in a series of small, interconnected basins between the mountain ranges, e.g. Park, later workers, like Cotton argued that the sediments had been isolated by later mountain growth. DouglasDouglas, B. J. 1986: Lignite resources of Central Otago. New Zealand Energy Research and Development Committee Publication P104: 367. placed the Manuherikia Group sediments into a coherent genetic context. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first epoch (geology), 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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentation
Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration, or electromagnetism. Settling is the falling of suspended particles through the liquid, whereas sedimentation is the final result of the settling process. In geology, sedimentation is the deposition of sediments which results in the formation of sedimentary rock. The term is broadly applied to the entire range of processes that result in the formation of sedimentary rock, from initial erosion through sediment transport and settling to the lithification of the sediments. However, the strict geological definition of sedimentation is the mechanical deposition of sediment particles from an initial suspension in air or water. Sedimentation may pertain to obje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58See the 2014 version of the ICS geologic time scale million years ago. It is the second and most recent epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Epoch and is followed by the Epoch. Prior to the 2009 revision of the geologic time sca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Miocene
The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene Epoch made up of two stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million years ago) to 5.333 Ma. The evolution of life The gibbons (family Hylobatidae) and orangutans (genus ''Pongo'') are the first groups to split from the line leading to the hominins, including humans, then gorillas (genus ''Gorilla''), and finally, chimpanzees and bonobo The bonobo (; ''Pan paniscus''), also historically called the pygmy chimpanzee and less often the dwarf chimpanzee or gracile chimpanzee, is an endangered great ape and one of the two species making up the genus '' Pan,'' the other being the comm ...s (genus '' Pan''). The splitting date between hominin and chimpanzee lineages is placed by some between 4 to 8 million years ago, that is, during the Late Miocene. References External links GeoWhen Database - Late Miocene .03 03 * * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Delta
A river delta is a landform shaped like a triangle, created by deposition of sediment that is carried by a river and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more rarely) another river that cannot carry away the supplied sediment. It is so named because its triangle shape resembles the Greek letter Delta. The size and shape of a delta is controlled by the balance between watershed processes that supply sediment, and receiving basin processes that redistribute, sequester, and export that sediment. The size, geometry, and location of the receiving basin also plays an important role in delta evolution. River deltas are important in human civilization, as they are major agricultural production centers and population centers. They can provide coastline defense and can impact drinking water supply. They are also ecologically important, with different species' assemblages depending on their landscape posit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depocenter
A depocenter or depocentre in geology is the part of a sedimentary basin where a particular rock unit has its maximum thickness. Depending on the controls on subsidence and the sedimentary environment the location of basin depocenters may vary with time, such as in active rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ... basins as extensional faults grow, link or become abandoned. References {{geology-stub Geology terminology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stromatolite
Stromatolites () or stromatoliths () are layered sedimentary formations ( microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). These microorganisms produce adhesive compounds that cement sand and other rocky materials to form mineral " microbial mats". In turn, these mats build up layer by layer, growing gradually over time. A stromatolite may grow to a meter or more. Although they are rare today, fossilized stromatolites provide records of ancient life on Earth. Morphology Stromatolites are layered, biochemical, accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains in biofilms (specifically microbial mats), through the action of certain microbial lifeforms, especially cyanobacteria. They exhibit a variety of forms and structures, or morphologies, including conical, stratiform, domal, columnar, and branchi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint Bathans Fauna
The St Bathans fauna is found in the lower Bannockburn Formation of the Manuherikia Group of Central Otago, in the South Island of New Zealand. It comprises a suite of fossilised prehistoric animals from the late Early Miocene (Altonian) period, with an age range of 19–16 million years ago. The layer in which the fossils are found derives from littoral zone sediments deposited in a shallow, freshwater lake, with an area of 5600 km2 from present day Central Otago to Bannockburn and the Nevis Valley in the west; to Naseby in the east; and from the Waitaki Valley in the north to Ranfurly in the south. The lake was bordered by an extensive floodplain containing herbaceous and grassy wetland habitats with peat-forming swamp–woodland. At that time the climate was warm with a distinctly subtropical Australian climate and the surrounding vegetation was characterised by casuarinas, eucalypts and palms as well as podocarps, araucarias and southern beeches. The fossilifero ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coal Forest
Coal forests were the vast swathes of wetlands that covered much of the Earth's tropical land areas during the late Carboniferous ( Pennsylvanian) and Permian times.Cleal, C. J. & Thomas, B. A. (2005). "Palaeozoic tropical rainforests and their effect on global climates: is the past the key to the present?" ''Geobiology'', ''3'', p. 13-31. As vegetable matter from these forests decayed, enormous deposits of peat accumulated, which later changed into coal. Much of the carbon in the peat deposits produced by coal forests came from photosynthetic splitting of existing carbon dioxide, which released the accompanying split-off oxygen into the atmosphere. This process may have greatly increased the oxygen level, possibly as high as about 35%, making the air more easily breathable by animals with inefficient respiratory systems, as indicated by the size of ''Meganeura'' compared to modern dragonflies. Coal forests covered tropical Euramerica (Europe, eastern North America, northwestern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meander
A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex bank which is typically a point bar. The result of this coupled erosion and sedimentation is the formation of a sinuous course as the channel migrates back and forth across the axis of a floodplain. The zone within which a meandering stream periodically shifts its channel is known as a meander belt. It typically ranges from 15 to 18 times the width of the channel. Over time, meanders migrate downstream, sometimes in such a short time as to create civil engineering challenges for local municipalities attempting to maintain stable roads and bridges.Neuendorf, K.K.E., J.P. Mehl Jr., and J.A. Jackson, J.A., eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. Charlton, R., 2007. ''Fundamen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint Bathans
St Bathans, formerly named Dunstan Creek, is a former gold and coal mining town in Central Otago, New Zealand. The settlement was a centre of the Otago Gold Rush, but mining has since long ceased. It is now largely a holiday retreat due to the preservation of many of its historic buildings. St Bathans is well known for Blue Lake, a small man-made lake created by gold-sluicing that transformed the 120-metre high Kildare Hill into a 168-metre deep pit. After mining stopped in 1934, the hole accumulated water, which turned a distinctive blue hue due to minerals from the surrounding rocks. It is currently a camping spot, and swimming is allowed in the lake. The town was named for the Scottish Borders village of Abbey St Bathans by early surveyor John Turnbull Thomson; the Scottish village was the birthplace of Thomson's maternal grandfather. It is 40 kilometres northwest of Ranfurly and 60 kilometres northeast of Alexandra, near the Dunstan Creek, beneath the St Bathans Range ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Lake (Otago)
Blue Lake is a small lake adjacent to the town of Saint Bathans in Central Otago, New Zealand. The lake is man-made, the result of sluicing In syntax, sluicing is a type of Ellipsis (linguistics), ellipsis that occurs in both direct and indirect interrogative clauses. The ellipsis is introduced by a ''wh''-expression, whereby in most cases, everything except the ''wh''-expression is e ... operations that began in 1873 when John Ewing (1844–1922) formed the St.Bathans Channel Company, to mine the Kildare Hill Gold Claim in St Bathans. His company constructed a tailings channel and introduced hydraulic elevating to work the claim. As this work progressed the Kildare Hill Claim became the site of the deepest hydraulic elevating operation in the world, that would turn a 120-metre hill into a 68-metre hole. Work stopped in 1902 when there was insufficient fall in the tailings channel to carry away the tailings. By 1905 John Ewing was bankrupt as a result of poor investments in o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
