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Middleton Basin
The Middleton Basin is a small sedimentary basin, in northeastern Massachusetts, containing Late Triassic and Early Jurassic red beds. Estimated to be 5.7 kilometers long and at most half a kilometer wide, it is one of the smallest basins in the state and is closely associated with the Newbury basins. A normal fault, striking northeast, is exposed on the southeastern margin of the basin, which separates it from surrounding Proterozoic crystalline basement rock. The red beds dip west. The basin is situated at a point where the Burlington mylonite zone and the Bloody Bluff fault The Bloody Bluff fault is the boundary between the Milford-Dedham zone and the Nashoba zone in eastern Massachusetts. It runs between Westborough, Massachusetts and Lynnfield, Massachusetts. In the south, into Connecticut, the component Lake Cha ... fade out and where the Milford-Dedham zone veers north. Mylonite never formed in the area because the young Triassic faults did not produce long-lastin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. The corresponding series (stratigraphy), series of rock beds is known as the Upper Triassic. The Late Triassic is divided into the Carnian, Norian and Rhaetian Geologic time scale, Ages. Many of the first dinosaurs evolved during the Late Triassic, including ''Plateosaurus'', ''Coelophysis'', and ''Eoraptor''. The Triassic–Jurassic extinction event began during this epoch and is one of the five major mass extinction events of the Earth. Etymology The Triassic was named in 1834 by Friedrich August von Namoh, Friedrich von Alberti, after a succession of three distinct rock layers (Greek meaning 'triad') that are widespread in southern Germany: the lower Buntsandstein (colourful sandstone'')'', t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma (million years ago), and ends at the start of the Middle Jurassic 174.1 Ma. Certain rocks of marine origin of this age in Europe are called "Lias Group, Lias" and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic. Origin of the name Lias There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an England, English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornwall, Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias limestone from S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Beds
Red beds (or redbeds) are sedimentary rocks, typically consisting of sandstone, siltstone, and shale, that are predominantly red in color due to the presence of ferric oxides. Frequently, these red-colored sedimentary strata locally contain thin beds of conglomerate, marl, limestone, or some combination of these sedimentary rocks. The ferric oxides, which are responsible for the red color of red beds, typically occur as a coating on the grains of sediments comprising red beds. Classic examples of red beds are the Permian and Triassic strata of the western United States and the Devonian Old Red Sandstone facies of Europe. Primary red beds Primary red beds may be formed by the erosion and redeposition of red soils or older red beds, but a fundamental problem with this hypothesis is the relative scarcity of red-colored source sediments of suitable age close to an area of red-bed sediments in Cheshire, England. Primary red beds may also form by in situ (early diagenetic) redd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newbury Basins
Newbury may refer to: Places United Kingdom * Newbury, Berkshire, a town * Newbury (district), Berkshire, a district formed in 1974 * Newbury (UK Parliament constituency) * Newbury, Kent, a hamlet * Newbury, Somerset, a hamlet United States * Newbury, Connecticut, former name of Brookfield * Newbury, Kansas, an unincorporated community * Newbury, Massachusetts, a town * Newbury, New Hampshire, a town * Newbury (town), Vermont ** Newbury (village), Vermont, within the town * Newbury Township, LaGrange County, Indiana * Newbury Township, Geauga County, Ohio Elsewhere * Newbury, Victoria, Australia, a locality * Newbury, Ontario, Canada, a village * Newbury, New Zealand, a rural community Schools * Newbury Biblical Institute, renamed Boston University in 1869 * Newbury Seminary, the oldest predecessor of Vermont College of Fine Arts * Newbury College (England), a further education college * Newbury College (United States), a career-focused college in Brookline, Massachuset ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proterozoic
The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided into three geologic eras (from oldest to youngest): the Paleoproterozoic, Mesoproterozoic, and Neoproterozoic. The Proterozoic covers the time from the appearance of oxygen in Earth's atmosphere to just before the proliferation of complex life (such as trilobites or corals) on the Earth. The name ''Proterozoic'' combines two forms of ultimately Greek origin: meaning 'former, earlier', and , 'of life'. The well-identified events of this eon were the transition to an oxygenated atmosphere during the Paleoproterozoic; the evolution of eukaryotes; several glaciations, which produced the hypothesized Snowball Earth during the Cryogenian Period in the late Neoproterozoic Era; and the Ediacaran Period (635 to 538.8 Ma) which is characterize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burlington Mylonite Zone
The Burlington mylonite zone is a 1.5 kilometer thick mylonite zone, resulting from the dynamic recrystallization and grain size reduction of rocks, running from Weston, Massachusetts to Lynnfield, Massachusetts and Danvers, Massachusetts. The deformation that formed the zone is believed to be related to the Bloody Bluff Fault. In 1976, R. O. Castle released information indicating that the Paleozoic Early Devonian Peabody Granite intruded the mylonite zone, giving a young age limit for the formation. The rocks within the Burlington mylonite zone are mainly fine-grained, laminated mylonites ranging to gneiss, with augen eye-shaped mineral grains. The zone also includes smaller includes of quartz schist and chlorite The chlorite ion, or chlorine dioxide anion, is the halite with the chemical formula of . A chlorite (compound) is a compound that contains this group, with chlorine in the oxidation state of +3. Chlorites are also known as salts of chlorous ac ... schist and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bloody Bluff Fault
The Bloody Bluff fault is the boundary between the Milford-Dedham zone and the Nashoba zone in eastern Massachusetts. It runs between Westborough, Massachusetts and Lynnfield, Massachusetts. In the south, into Connecticut, the component Lake Char fault is poorly exposed. The Bloody Bluff fault zone is 3.2 kilometers wide in Framingham, Massachusetts and forms the five kilometer wide Burlington mylonite zone The Burlington mylonite zone is a 1.5 kilometer thick mylonite zone, resulting from the dynamic recrystallization and grain size reduction of rocks, running from Weston, Massachusetts to Lynnfield, Massachusetts and Danvers, Massachusetts. The de ... to the north. Rocks along the fault have experienced both ductile and brittle deformation. There is relatively little mylonite in the vicinity of Westborough. The fault is visible along I-495 just east of Westborough and further east, the Bloody Bluff-Lake Char fault splits into smaller branches. One of these faults, tentati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mylonite
Mylonite is a fine-grained, compact metamorphic rock produced by dynamic recrystallization of the constituent minerals resulting in a reduction of the grain size of the rock. Mylonites can have many different mineralogical compositions; it is a classification based on the textural appearance of the rock. Formation Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones. There are many different views on the formation of mylonites, but it is generally agreed that crystal-plastic deformation must have occurred, and that fracturing and cataclastic flow are secondary processes in the formation of mylonites. Mechanical abrasion of grains by milling does not occur, although this was originally thought to be the process that formed mylonites, which were named from the Greek μύλος ''mylos'', meaning mill. Mylonites form at depths of no less than 4 km. There are many different mechanisms that accommodate crystal-plastic def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the chief terrestrial vertebrates during this time. A specialized subgroup of archo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Massachusetts
The geology of Massachusetts includes numerous units of volcanic, intrusive igneous, metamorphic and sedimentary rocks formed within the last 1.2 billion years. The oldest formations are gneiss rocks in the Berkshires, which were metamorphosed from older rocks during the Proterozoic Grenville orogeny as the proto-North American continent Laurentia collided against proto-South America. Throughout the Paleozoic, overlapping the rapid diversification of multi-cellular life, a series of six island arcs collided with the Laurentian continental margin. Also termed continental terranes, these sections of continental rock typically formed offshore or onshore of the proto-African continent Gondwana and in many cases had experienced volcanic events and faulting before joining the Laurentian continent. These sequential collisions metamorphosed new rocks from sediments, created uplands and faults and resulted in widespread volcanic activity. Simultaneously, the collisions raised the Appalachia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
