Mount Hope Bay is a tidal estuary located at the mouth of the Taunton River on the Massachusetts and Rhode Island border. It is an arm of Narragansett Bay . The bay is named after Mount Hope , a small hill located on its western shore in what is now Bristol, Rhode Island . It flows into the East Passage of Narragansett Bay and also the Sakonnet River . Mount Hope Bay has played an important role to the history of the area, from pre-colonial times to the present. While many years of sewage and industrial pollution have severely degraded the quality of the shallow waters of the bay, there are currently major efforts underway to clean up and restore it.
30-591: Mount Hope Bay is part of the Narragansett Basin, formed as a rift in the Avalon terrane. It is underlaid by sedimentary rocks estimated to be several miles thick. The bay covers an area of about 13 square miles (36 square km), with an average depth of 18.7 feet, although portions of the southern end of the bay are as deep as 74 feet near the Mount Hope Bridge . At the north end of the bay are
60-548: A geological history from later in the early Cambrian until the mid-Orodovician. Subduction evolved along the shores of Gondwana, which caused Avalonia to rift away and begin its northbound journey towards Baltica during late Cambrian and Early Ordovician. The Rheic Ocean opened behind the Avalonian microcontinents. This independent movement of Avalonia started from a latitude of about 60° South. The eastern end of Avalonia collided with Baltica at 30°S, an event which closed
90-536: Is considered a microcontinent, though not a continental fragment. Other hotspot islands such as the Hawaiian Islands and Iceland are considered neither microcontinents nor continental fragments. Not all islands can be considered microcontinents: Borneo , the British Isles , Newfoundland , and Sri Lanka , for example, are each within the continental shelf of an adjacent continent, separated from
120-456: Is expected to be completed by 2018. 41°41′N 71°13′W / 41.683°N 71.217°W / 41.683; -71.217 ( Mount Hope Bay ) Avalonia Avalonia was a microcontinent in the Paleozoic era . Crustal fragments of this former microcontinent underlie south-west Great Britain , southern Ireland , and the eastern coast of North America . It is
150-420: Is poorly known, but, based on isotopic analyses , proto-Avalonia most likely evolved together with Carolina about 800 Ma from volcanic arcs far offshore from the supercontinent Rodinia , most likely outboard continental terranes of more obvious West African affinities, such as Cadomia and Iberia . About 650 Ma the Avalonian belt collided with Gondwana. Avalonia originally developed along
180-753: Is the largest of the peri-Gondwanan terranes, a series of continental blocks that more or less simultaneously broke off the margins of the southern supercontinent Gondwana and therefore share an early Paleozoic marine fauna. They were pulled northward and eventually collided to form the Appalachian , Caledonide , and Variscan orogens . West Avalonia, in North America, stretches from New England to Atlantic Canada, and East Avalonia, in Europe, from southern Britain to Brabant. Other Peri-Gondwanan terranes, sometimes called "Greater Avalonia", include Carolina in
210-425: Is very similar to that of typical continental crust. Strike-slip fault zones cause the fragmentation of microcontinents. The zones link the extensional zones where continental pieces are already isolated through the remaining continental bridges. Additionally, they facilitate quick crustal thinning across narrow zones and near-vertical strike-slip-dominated faults . They develop fault-block patterns that slice
240-582: The Acadian orogeny . In the Carboniferous , the new continent and another terrane, Armorica which included Iberia , drifted in from Gondwana, trapping Avalonia between it and the continent so adding Iberia/Armorica to Euramerica. This was followed up by the arrival of Gondwana. The effects of these collisions are seen in Europe as the Variscan folding . In North America it shows as later phases of
270-656: The Ardennes of Belgium and north-eastern France, north Germany, north-western Poland, south-eastern Ireland, and the south-western edge of the Iberian Peninsula . Part of the British-Belgian section formed an island in the Carboniferous, affecting the disposition of coalfields; this is known by names such as the ' London-Brabant Island '. Its bulk had an effect on the geological structure between
300-469: The Caribbean Sea , are composed largely of granitic rock as well, but all continents contain both granitic and basaltic crust, and there is no clear dividing line between islands and microcontinents under such a definition. The Kerguelen Plateau is a large igneous province formed by a volcanic hotspot ; however, it was associated with the breakup of Gondwana and was for a time above water, so it
330-932: The Tornquist Sea , during the Late Ordovician. In Avalonia, folding, faulting, and volcanism followed – as evidenced in the Welsh Borderland and the Taconic deformation in Laurentia ;– some or all of which are related to the collision. Plinian eruptions resulted from the subduction beneath Avalonia and produced thick layers of K-bentonite in southwestern Baltica, while the Millbrig eruptions occurred in Laurentia. This Late Ordovician magmatism peaked between 457 and 449 Ma. In
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#1732783055127360-623: The Acadian orogeny. This was happening at around the Equator during the later Carboniferous, forming Pangaea with Avalonia near its centre but partially flooded by shallow sea. In the Jurassic , Pangaea split into Laurasia and Gondwana, with Avalonia as part of Laurasia. In the Cretaceous , Laurasia broke up into North America and Eurasia with Avalonia split between them. Iberia
390-927: The Appalachian and the deep bedrock of Florida in North America, Oaxaquia and Yucatán in Mexico, and the Chortis Block in Central America. The North American terranes of Ganderia and Carolinia are sometimes grouped with Avalonia because they were transferred together across the Iapetus Ocean. Sometimes the Meguma terrane in Nova Scotia is also included. The Avalonian part of Great Britain almost exactly coincides with England and Wales. Elsewhere in Europe, parts of Avalonia are found in
420-758: The Ardennes and the English Midlands by influencing the subsequent crustal folding resulting from the Variscan collision. In Canada, Avalonia comprises the Avalon Peninsula of southeast Newfoundland , southern New Brunswick , part of Nova Scotia , and Prince Edward Island . In the United States, Avalonia consists of northern coastal Maine , all of Rhode Island , and other sections of coastal New England . The basement of Avalonia
450-686: The Rhode Island border. The perimeter of the bay is crossed by three roadway bridges: the Sakonnet River Bridge to the southeast, the Charles M. Braga Jr. Memorial Bridge to the north, and the Mount Hope Bridge to the southwest. Mount Hope Bay contains a 35 foot-deep shipping channel maintained by the Army Corps of Engineers as part of their Fall River Harbor project. A privately maintained, 34 feet-deep channel extends from
480-651: The bay is located within Rhode Island . However, nearly 90 percent of its drainage area is located within Massachusetts . Its main tributary is the Taunton River , and several smaller rivers drain directly into the bay, including the Quequechan River , Lee's River , Cole River , and Kickemuit River . A small sand bar known as Spar Island is located in the middle of the bay just south of
510-560: The continental fragments to form most likely impacts their layers and overall thickness along with the addition of mafic intrusions to the crust. Studies have determined that the average crustal thickness of continental fragments is approximately 24.8 ± 5.7 kilometres (15.4 ± 3.5 mi). The sedimentary layer of continental fragments can be up to 5 kilometres (3.1 mi) thick and can overlay two to three crustal layers. Continental fragments have an average crustal density of 2.81 g/cm (0.102 lb/cu in) which
540-462: The continents Baltica , then Laurentia , and finally with Gondwana, ending up in the interior of Pangea . When Pangea broke up, Avalonia's remains were divided by the rift which became the Atlantic Ocean . When the term "Avalon" was first coined by Canadian geologist Harold Williams in 1964, he included only Precambrian rocks in eastern Newfoundland. More than a decade later he extended
570-724: The industrial history of the city of Fall River , which is located on its eastern shore. The bay provides access to the city for ocean-going vessels, including for many years the passenger ships of the Fall River Line . In the 1960s, the 1,500 megawatt Brayton Point Power Station was built by the New England Power Company in Somerset, Massachusetts at the north end of the bay. It has the largest capacity of any power plant in New England . For many years,
600-510: The late Silurian and lower Devonian , the combined Baltica and Avalonia collided progressively with Laurentia , beginning with the long extremity of Avalonia, which is now attached to North America. The result of this was the formation of Euramerica . At the completion of this stage, the site of Britain was at 30°S and Nova Scotia at about 45°S. This collision is represented by the Caledonian folding or in North America as an early phase in
630-708: The main ACOE channel to the Brayton Point Power Station. Mount Hope Bay was once part of the Wampanoag Nation, and the site of early events of King Philip's War in 1675. For nearly 200 years, the area of the bay was part of a boundary dispute between the states of Rhode Island and Massachusetts , which was finally settled by the United States Supreme Court in 1862. Mount Hope Bay has played an important part in
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#1732783055127660-462: The mainland by inland seas flooding its margins. Several islands in the eastern Indonesian Archipelago are considered continental fragments, although this designation is controversial. The archipelago is home to numerous microcontinents with complex geology and tectonics. This makes it complicated to classify landmasses and determine causation for the formation of the landmass. These include southern Bacan , Banggai - Sulu Islands ( Sulawesi ),
690-560: The plant has relied on the waters of the bay as part of its cooling process. This has led to severe thermal pollution, resulting in periodic fish kills . After years of lawsuits and various environmental government action, current owner Dominion Resources spent approximately $ 500 million building two 500-foot tall cooling towers and upgrading the cooling system to prevent pollution of the bay. The plant closed in 2017 and cooling towers were demolished in April 2019. The power station brownfield
720-481: The portion of continent into detachable slivers. The continental fragments are located at various angles from their transform faults . Some microcontinents are fragments of Gondwana or other ancient cratonic continents; examples include Madagascar ; the northern Mascarene Plateau , which includes the Seychelles Microcontinent ; and the island of Timor . Other islands, such as several in
750-830: The shores of Rodinia together with island arcs now found in the Arabian-Nubian Shield (900–700 Ma) and Tocantins in central Brazil (950–900 Ma) and the basement of Avalonia is most likely of the same age. During the Precambrian-Cambrian transition, Avalonia was located in a cool-water environment and even underwent a glaciation. The Moroccan Anti-Atlas range in West Gondwana was, in contrast, characterised by evaporites , evidence of desiccation , and had thrombolites . Avalonia and Gondwana must therefore have been located far from each other during this period. The two did, however, share
780-543: The source of many of the older rocks of Western Europe , Atlantic Canada , and parts of the coastal United States . Avalonia is named for the Avalon Peninsula in Newfoundland . Avalonia developed as a volcanic arc on the northern margin of Gondwana . It eventually rifted off, becoming a drifting microcontinent. The Rheic Ocean formed behind it, and the Iapetus Ocean shrank in front. It collided with
810-488: The term to include all exotic rocks from Newfoundland down to Rhode Island. Since the introduction of the term terrane in the 1980s, Avalonia has been referred to as "platform", "composite terrane", "superterrane", "East" and "West Avalonia", and "Avalon sensu lato". "Avalonia" can thus refer exclusively to rocks in Newfoundland (Avalonia sensu stricto ), an assembly of terranes, or a single tectonic unit. Avalonia
840-418: The towns of Warren, Rhode Island , Swansea, Massachusetts , and Somerset, Massachusetts . The eastern shore of the bay consists of the city of Fall River, Massachusetts and the town of Tiverton, Rhode Island . Portsmouth, Rhode Island is located at the southern end of the bay at the northern tip of Aquidneck Island . Bristol, Rhode Island forms the western shore of the bay. Approximately 70 percent of
870-1370: Was later rotated away again as the African part of Gondwana strike-slipped past it. This last movement caused the Alpine orogeny including the raising of the Pyrenees during the Miocene and Pliocene . As a result of this, part of Avalonia is now to be found on each side of the Straits of Gibraltar . [REDACTED] Africa [REDACTED] Antarctica [REDACTED] Asia [REDACTED] Australia [REDACTED] Europe [REDACTED] North America [REDACTED] South America [REDACTED] Afro-Eurasia [REDACTED] Americas [REDACTED] Eurasia [REDACTED] Oceania Microcontinent Continental crustal fragments , partly synonymous with microcontinents , are pieces of continents that have broken off from main continental masses to form distinct islands that are often several hundred kilometers from their place of origin. Continental fragments and microcontinent crustal compositions are very similar to those of regular continental crust . The rifting process that caused
900-585: Was purchased in 2018 and became the Brayton Point Commerce Center. It was upgraded and adapted it into offshore wind port which can support heavy-lift port operations and receive deep-draft vessels. In 2009, the City of Fall River completed the first phase of a $ 185 million Combined Sewer Overflow (CSO) abatement project, designed to drastically reduce the amount of sewage overflows that occur during periods of heavy rains. The project
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