The Grenville Province is a tectonically complex region, in Eastern Canada, that contains many different aged accreted terranes from various origins. It exists southeast of the Grenville Front [1] and extends from Labrador southwestern to Lake Huron. It is bounded by the St. Lawrence River/Seaway to the southeast. [2]
The Grenville Front separates the Grenville Province from the Superior Craton. Adjacent to the Grenville Front is the Parautochthonous Belt. The Parautochthonous Belt is made of rocks originally derived from the Superior Craton, which have been metamorphosed and reworked since their emplacement. [3] The rocks to the southwest of the Parautochthonous Belt are various accreted terranes that have been thrust upon or emplaced during the various tectonic events that have taken place from 2.0 to 0.98 billion years ago. The compositions of these terranes are unique and have distinct depleted mantle model ages.
During the formation of the Grenville Province, the type of tectonism changed. The earliest stages of formation were dominated by arrested subduction. The type of tectonism then changed to flat slab subduction. In the late stages of formation the tectonism changed to collisional orogenesis. Although there has been many studies done on the Grenville Province, the origins of the various terranes are still not fully understood and may never be fully known.
The Central Metasedimentary Boundary Thrust Zone makes up the northwestern boundary of the Central Metasedimentary Belt. It was created during the Shawinigan Orogeny (1.19-1.14 Ga). [3] [4] The Central Metasedimentary Belt is bordered to the south by Phanerozoic sedimentary rocks and Lake Ontario.
In the northeastern central Metasedimentary Belt, the rocks are composed of Orthogneiss. The region is known as the Bondy and LaCoste domical complexes. In the southwestern Metasedimentary Belt, the rocks are tonalitic to granitic orthogneisses.
Nd model ages of the Central Metasedimentary Belt range from 1.55 to 1.4 Ga. The origin of this area can be attributed to rifting (which made the accommodation for the sediments) and subsequent thrusting from the collision with Amazonia.
Barillia is located northeast of Lake Huron. [5] It is bound by the allochthon boundary thrust and Algonquia to the south, and Laurentia to the north. It is an accreted arc that was accreted during the Penokean orogeny. Barillia's composition is calc-alkaline granitic gneiss. Nd model ages of Barillia are around 1.90 Ga. [3]
Makkovikia is located in eastern Labrador. It was created during the Makkovik orogeny. An Andean-type arc developed and was accreted onto the preexisting continental rocks. Makkovikia's composition is rather complicated. The Kaipokok domain has both Archean crust and Paleoproterozoic volcanics and sedimentary rocks. Within the Aillik and Cape Harrison domains, there are plutonic rocks. [6] Nd model ages of Makkovikia are around 1.90 Ga. [3]
Labradoria is located in northeastern Québec. Labradoria is part of an Andean style arc that accreted around 1.67-1.66 Ga. It was later intruded by continental arc plutons during Pinwarian orogeny. It is composied of calc-alkaline batholiths. Nd model ages of Labradoria are around 1.70. Ga. [3]
Quebecia is located in central Québec near Baie-Comeau and Forestville. It is bordered to the south by the St. Lawrence River. Quebecia is an accreted arc and is calk-alkaline in composition. Nd model ages of Quebecia are around 1.55 Ga. [3] [7]
Mekinac is located northeast of Ottawa, Canada. It was created with Andean-style magmatism. The origin is not fully understood, but is thought to be related to the origin of the Adirondacks. This makes it related to the Shawinigan orogeny. Its composition is tonalitic gneiss. Nd model ages of Mekinac are around 1.4-1.5 Ga. [3]
Morin is located near Ottawa, Canada. It was a terrane that was thrust up during the Shawinigan orogeny around 1.19-1.16 Ga. Its composition is Anorthosite-mangerite-charnockite-granite. Nd model ages of Morin are around 1.3-1.5 Ga. [3]
The Adirondacks are located in northeastern New York, United States. The Adirondacks were accreted during the Shawinigan orogeny. This is evidenced by the deformation in the allochthonous monocyclic belt. The Highlands and Lowlands of the Adirondacks were separated before the Shawinigan orogeny. This is evidenced by differing compositions of plutonic rocks. Only the Highlands experienced Ottawan high-temperature metamorphism while the Lowlands displaced along Carthage-Colton shear zone and ended up next to Highlands.
The composition of the Southern Adirondacks consists of orthoquartzite. In the Adirondack Lowlands there are ophiolites and calc-alkaline granitoids. In the Adirondack Highlands orthogneisses are present with metapelitic migmatites.
The Adirondacks as a whole do not contain Archean zircons and therefore rocks are not sourced from Laurentia. It has a Nd model age ranging from 1.3 to 1.5 Ga. [3]
Algonquia is located east of the Georgian Bay in Ontario, Canada. It was an allochthon that was thrust up onto existing continental rock. The plutonic ages do not match surrounding rocks, which gives evidence of it being an exotic terrane. Algonquia's composition is orthogneiss, diorite, and quartz-dioritic orthogneiss. Its Nd model age is between 1.6 and 1.9 Ga. [3] [8]
Parry Sound is located east of the Georgian Bay in Ontario, Canada. Parry Sound is a nappe that was thrust up on existing continental rock. This is proven by the similarities of the compositions to the Central Metasedimentary Belt and the Adirondack Highlands. The quartzite is evidence that the three terranes were all continuous at one point due to the zircons contained within it matching the Central Metasedimentary Belt and the Adirondack Highlands. Parry Sound is composed of migmatitic quartzite, gneiss, anorthosite, and gabbro. Its Nd model age is around 1.4-1.6 Ga. [3] [9]
The ductile lower crust of the nappes allowed for the terranes to be accreted on the continental margin via a lower crustal indenter. Later events such as late-stage thrusting and extension can be attributed to gravitational spreading. [10]
In the Paleoproterozoic, the Grenville Province was controlled by arrested subduction. During the beginning stages of the Mesoproterozoic (1.60-1.23 Ga) the Grenville Province was controlled by flat slab subduction. By the later stages of the Mesoproterozoic (1.23-0.90 Ga), the Grenville Province was controlled by pressure-point orogenesis. [11]
The Algonquian terrane was accreted during this orogeny.
Juvenile crust was developed without interaction of the older crustal material. Terranes accreted during this time are related to the Makkovikian and Penokean orogenies.
A calc-alkaline arc was accreted on preexisting Laurentia.
Metamorphism of the arc and preexisting Laurentia took place creating mylonite zones.
Crustal thickening represented by the accreted arc on preexisting Laurentia caused magmatism.
A passive margin that accumulated sediment formed due to lack of tectonic activity.
The subduction zone central location changes from south to north during this time.
There is a continuation of the passive margin during this time.
Felsic magmatism dominates this time period. The cause of the magmatism is debated between an extensional setting or a continental-margin arc. The name is in relation to the ensuing orogeny and metamorphism.
Pinwarian magmatism has stopped by this time. Gabbros were formed in the northern Grenville Province around 1.46-1.43 Ga, named the Michael-Shabogamo gabbros. From 1.42 to 1.35 Ga, there is no magmatic activity. After this period and until the end of the mid-Elsonian, the Nain Plutonic Suite is emplaced in Labrador. [12]
Felsic magmatism dominates the north and south areas of Labrador while mafic magmatism dominates the central area of Labrador.
Felsic magmatism ceases and accretion of island arcs occurs in the Central Metasedimentary Belt.
Mixed compression and extension caused broad mafic magmatism during this time. This could be related to the Shawinigan orogeny which occurred in the southwestern region of the Grenville Province. [13]
During this time, deformation and metamorphism was widely spread throughout the entire Grenville Province but the level of intensity varied. The exterior section of the province was subject to more deformation and metamorphism, while the interior was subject to more magmatism. The magmatism was exclusively in preexisting crust.
Baltica is a paleocontinent that formed in the Paleoproterozoic and now constitutes northwestern Eurasia, or Europe north of the Trans-European Suture Zone and west of the Ural Mountains. The thick core of Baltica, the East European Craton, is more than three billion years old and formed part of the Rodinia supercontinent at c. 1 Ga.
The Acadian orogeny is a long-lasting mountain building event which began in the Middle Devonian, reaching a climax in the early Late Devonian. It was active for approximately 50 million years, beginning roughly around 375 million years ago, with deformational, plutonic, and metamorphic events extending into the Early Mississippian. The Acadian orogeny is the third of the four orogenies that formed the Appalachian orogen and subsequent basin. The preceding orogenies consisted of the Potomac and Taconic orogeny, which followed a rift/drift stage in the Late Neoproterozoic. The Acadian orogeny involved the collision of a series of Avalonian continental fragments with the Laurasian continent. Geographically, the Acadian orogeny extended from the Canadian Maritime provinces migrating in a southwesterly direction toward Alabama. However, the Northern Appalachian region, from New England northeastward into Gaspé region of Canada, was the most greatly affected region by the collision.
The Taconic orogeny was a mountain building period that ended 440 million years ago and affected most of modern-day New England. A great mountain chain formed from eastern Canada down through what is now the Piedmont of the East coast of the United States. As the mountain chain eroded in the Silurian and Devonian periods, sediments from the mountain chain spread throughout the present-day Appalachians and midcontinental North America.
The Nevadan orogeny occurred along the western margin of North America during the Middle Jurassic to Early Cretaceous time which is approximately from 155 Ma to 145 Ma. Throughout the duration of this orogeny there were at least two different kinds of orogenic processes occurring. During the early stages of orogenesis an "Andean type" continental magmatic arc developed due to subduction of the Farallon oceanic plate beneath the North American Plate. The latter stages of orogenesis, in contrast, saw multiple oceanic arc terranes accreted onto the western margin of North America in a "Cordilleran type" accretionary orogen. Deformation related to the accretion of these volcanic arc terranes is mostly limited to the western regions of the resulting mountain ranges and is absent from the eastern regions. In addition, the deformation experienced in these mountain ranges is mostly due to the Nevadan orogeny and not other external events such as the more recent Sevier and Laramide Orogenies. It is noted that the Klamath Mountains and the Sierra Nevada share similar stratigraphy indicating that they were both formed by the Nevadan orogeny. In comparison with other orogenic events, it appears that the Nevadan Orogeny occurred rather quickly taking only about 10 million years as compared to hundreds of millions of years for other orogenies around the world.
The Grenville orogeny was a long-lived Mesoproterozoic mountain-building event associated with the assembly of the supercontinent Rodinia. Its record is a prominent orogenic belt which spans a significant portion of the North American continent, from Labrador to Mexico, as well as to Scotland.
The Slave Craton is an Archaean craton in the north-western Canadian Shield, in Northwest Territories and Nunavut. The Slave Craton includes the 4.03 Ga-old Acasta Gneiss which is one of the oldest dated rocks on Earth. Covering about 300,000 km2 (120,000 sq mi), it is a relatively small but well-exposed craton dominated by ~2.73–2.63 Ga greenstones and turbidite sequences and ~2.72–2.58 Ga plutonic rocks, with large parts of the craton underlain by older gneiss and granitoid units. The Slave Craton is one of the blocks that compose the Precambrian core of North America, also known as the palaeocontinent Laurentia.
The Kalahari Craton is a craton, an old and stable part of the continental lithosphere, that occupies large portions of South Africa, Botswana, Namibia and Zimbabwe. It consists of two cratons separated by the Limpopo Belt: the larger Kaapvaal Craton to the south and the smaller Zimbabwe Craton to the north. The Namaqua Belt is the southern margin of the Kaapvaal Craton.
The Wyoming Craton is a craton in the west-central United States and western Canada – more specifically, in Montana, Wyoming, southern Alberta, southern Saskatchewan, and parts of northern Utah. Also called the Wyoming Province, it is the initial core of the continental crust of North America.
The Algoman orogeny, known as the Kenoran orogeny in Canada, was an episode of mountain-building (orogeny) during the Late Archean Eon that involved repeated episodes of continental collisions, compressions and subductions. The Superior province and the Minnesota River Valley terrane collided about 2,700 to 2,500 million years ago. The collision folded the Earth's crust and produced enough heat and pressure to metamorphose the rock. Blocks were added to the Superior province along a 1,200 km (750 mi) boundary that stretches from present-day eastern South Dakota into the Lake Huron area. The Algoman orogeny brought the Archean Eon to a close, about 2,500 million years ago; it lasted less than 100 million years and marks a major change in the development of the Earth's crust.
The Sveconorwegian orogeny was an orogenic system active 1140 to 960 million years ago and currently exposed as the Sveconorwegian orogenic belt in southwestern Sweden and southern Norway. In Norway the orogenic belt is exposed southeast of the front of the Caledonian nappe system and in nappe windows. The Sveconorwegian orogen is commonly grouped within the Grenvillian Mesoproterozoic orogens. Contrary to many other known orogenic belts the Sveconorwegian orogens eastern border does not have any known suture zone with ophiolites.
The Svecofennian orogeny is a series of related orogenies that resulted in the formation of much of the continental crust in what is today Sweden and Finland plus some minor parts of Russia. The orogenies lasted from about 2000 to 1800 million years ago during the Paleoproterozoic Era. The resulting orogen is known as the Svecofennian orogen or Svecofennides. To the west and southwest the Svecofennian orogen limits with the generally younger Transscandinavian Igneous Belt. It is assumed that the westernmost fringes of the Svecofennian orogen have been reworked by the Sveconorwegian orogeny just as the western parts of the Transscandinavian Igneous Belt has. The Svecofennian orogeny involved the accretion of numerous island arcs in such manner that the pre-existing craton grew with this new material from what is today northeast to the southwest. The accretion of the island arcs was also related to two other processes that occurred in the same period; the formation of magma that then cooled to form igneous rocks and the metamorphism of rocks.
The Famatinian orogeny is an orogeny that predates the rise of the Andes and that took place in what is now western South America during the Paleozoic, leading to the formation of the Famatinian orogen also known as the Famatinian belt. The Famatinian orogeny lasted from the Late Cambrian to at least the Late Devonian and possibly the Early Carboniferous, with orogenic activity peaking about 490 to 460 million years ago. The orogeny involved metamorphism and deformation in the crust and the eruption and intrusion of magma along a Famatinian magmatic arc that formed a chain of volcanoes. The igneous rocks of the Famatinian magmatic arc are of calc-alkaline character and include gabbros, tonalites, granodiorites and trondhjemites. The youngest igneous rocks of the arc are granites.
Patagonia comprises the southernmost region of South America, portions of which lie on either side of the Argentina-Chile border. It has traditionally been described as the region south of the Rio Colorado, although the physiographic border has more recently been moved southward to the Huincul fault. The region's geologic border to the north is composed of the Rio de la Plata craton and several accreted terranes comprising the La Pampa province. The underlying basement rocks of the Patagonian region can be subdivided into two large massifs: the North Patagonian Massif and the Deseado Massif. These massifs are surrounded by sedimentary basins formed in the Mesozoic that underwent subsequent deformation during the Andean orogeny. Patagonia is known for its vast earthquakes and the damage they cause.
The Mars Hill Terrane (MHT) is a belt of rocks exposed in the southern Appalachian Mountains, between Roan Mountain, North Carolina and Mars Hill, North Carolina. The terrane is located at the junction between the Western Blue Ridge and the Eastern Blue Ridge Mountains.
The geology of Quebec involves several different geologic provinces, made up of ancient Precambrian crystalline igneous and metamorphic rock, overlain by younger sedimentary rocks and soils. Most of southern Quebec is dominated by the Grenville Province, while the vast north is divided between the large Superior Province and the Churchill Province to the east, near Labrador.
The geology of North Carolina includes ancient Proterozoic rocks belonging to the Grenville Province in the Blue Ridge. The region experienced igneous activity and the addition of new terranes and orogeny mountain building events throughout the Paleozoic, followed by the rifting of the Atlantic Ocean and the deposition of thick sediments in the Coastal Plain and offshore waters.
The Superior Craton is a stable crustal block covering Quebec, Ontario, and southeast Manitoba in Canada, and northern Minnesota in the United States. It is the biggest craton among those formed during the Archean period. A craton is a large part of the Earth's crust that has been stable and subjected to very little geological changes over a long time. The size of Superior Craton is about 1,572,000 km2. The craton underwent a series of events from 4.3 to 2.57 Ga. These events included the growth, drifting and deformation of both oceanic and continental crusts.
The Mazatzal orogeny was an orogenic event in what is now the Southwestern United States from 1650 to 1600 Mya in the Statherian Period of the Paleoproterozoic. Preserved in the rocks of New Mexico and Arizona, it is interpreted as the collision of the 1700-1600 Mya age Mazatzal island arc terrane with the proto-North American continent. This was the second in a series of orogenies within a long-lived convergent boundary along southern Laurentia that ended with the ca. 1200–1000 Mya Grenville orogeny during the final assembly of the supercontinent Rodinia, which ended an 800-million-year episode of convergent boundary tectonism.
The Yavapai orogeny was an orogenic (mountain-building) event in what is now the Southwestern United States that occurred between 1710 and 1680 million years ago (Mya), in the Statherian Period of the Paleoproterozoic. Recorded in the rocks of New Mexico and Arizona, it is interpreted as the collision of the 1800-1700 Mya age Yavapai island arc terrane with the proto-North American continent. This was the first in a series of orogenies within a long-lived convergent boundary along southern Laurentia that ended with the ca. 1200–1000 Mya Grenville orogeny during the final assembly of the supercontinent Rodinia, which ended an 800-million-year episode of convergent boundary tectonism.
The Picuris orogeny was an orogenic event in what is now the Southwestern United States from 1.43 to 1.3 billion years ago in the Calymmian Period of the Mesoproterozoic. The event is named for the Picuris Mountains in northern New Mexico and interpreted either as the suturing of the Granite-Rhyolite crustal province to the southern margin of the proto-North American continent Laurentia or as the final suturing of the Mazatzal crustal province onto Laurentia. According to the former hypothesis, this was the second in a series of orogenies within a long-lived convergent boundary along southern Laurentia that ended with the ca. 1200–1000 Mya Grenville orogeny during the final assembly of the supercontinent Rodinia, which ended an 800-million-year episode of convergent boundary tectonism.