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Terrane

About: Terrane is a research topic. Over the lifetime, 11025 publications have been published within this topic receiving 442596 citations. The topic is also known as: tectonostratigraphic terrane.


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Journal ArticleDOI
TL;DR: The Lachlan Orogen, like many other orogenic belts, has undergone paradigm shifts from geosynclinal to plate-tectonic theory of evolution over the past 40 years as mentioned in this paper.
Abstract: The Lachlan Orogen,like many other orogenic belts,has undergone paradigm shifts from geosynclinal to plate-tectonic theory of evolution over the past 40 years. Initial plate-tectonic interpretations were based on lithologic associations and recognition of key plate-tectonic elements such as andesites and palaeo-subduction complexes. Understanding and knowledge of modern plate settings led to the application of actualistic models and the development of palaeogeographical reconstructions, commonly using a non-palinspastic base. Igneous petrology and geochemistry led to characterisation of granite types into ‘I’ and ‘S’, the delineation of granite basement terranes, and to non-mobilistic tectonic scenarios involving plumes as a heat source to drive crustal melting and lithospheric deformation. More recently, measurements of isotopic tracers (Nd, Sr, Pb) and U–Pb SHRIMP age determinations on inherited zircons from granitoids and detrital zircons from sedimentary successions led to the development of multiple ...

222 citations

Journal ArticleDOI
TL;DR: The Kohistan arc terrane comprises an intra-oceanic island arc of Cretaceous age separating the Indian plate to the south from the Karakoram (Asian) plate within the Indus suture zone of north Pakistan.
Abstract: The Kohistan arc terrane comprises an intra-oceanic island arc of Cretaceous age separating the Indian plate to the south from the Karakoram (Asian) plate to the north within the Indus suture zone of north Pakistan. The intra-oceanic arc volcanics (Chalt, Dras Group) were built on a foundation of dominantly mid-ocean ridge basalt (MORB)-related amphibolites of the Kamila Group. The subarc magma chamber is represented by multiple intrusions of a huge gabbro-norite complex (Chilas complex), which includes some ultramafic assemblages of residual mantle harzburgite and dunite, layered cumulates, and hornblendites cut by late stage dikes of hornblende + plagioclase pegmatites. The Chilas complex norites intrude the Gilgit metasediments of lower amphibolite and greenschist facies in northern Kohistan, which also form xenolithic roof pendants within the top of the Chilas complex. Along the southern margin of Kohistan, Jijal and Sapat complex ultramafics (dunites, harzburgites and websterites) form remnant suprasubduction zone ophiolitic mantle rocks along the hanging wall of the Main Mantle Thrust, the Cretaceous obduction plane along which Kohistan was emplaced onto Indian plate rocks. Garnet granulites of the Jijal complex, formed at 12–14 kbars, represent original magmatic lower crustal rocks subducted to depths of at least 45 km and metamorphosed during high-pressure and high-temperature subduction of earlier arc-related rocks. Obduction of the Sapat ophiolite and Kohistan arc occurred between ∼75 and 55 Ma. The closure of the Shyok suture zone separating Kohistan from the Karakoram plate must have occurred prior to 75 Ma, the age of the Jutal basic dikes which crosscut the closure-related fabrics, mainly late north directed backthrusting in the lower Hunza valley. Andean-type granitoid (gabbrodiorite-granodiorite-granite) emplacement along the Kohistan-Ladakh batholith ended at the time of India-Asia collision, ∼ 60–50 Myr ago. Postcollisional crustal thickening along the Karakoram led to multiple episodes of metamorphism from latest Cretaceous and throughout the Tertiary. Sillimanite grade metamorphism in Hunza was actually pre-India-Asia collision and may have resulted from the earlier Kohistan collision. Localized and sporadic crustal melting episodes across northern Kohistan (Indus confluence and Parri granite sheets) and the southern Karakoram (Hunza dikes and Sumayar and Mango Gusar leucogranites) occurred from 51 to 9 Ma and culminated in the huge Baltoro monzogranite-leucogranite intrusion 25–21 Myr ago. A vast network of leucogranitic and pegmatitite dikes containing gem quality aquamarine + muscovite ± tourmaline ± garnet ± biotite quartz are younger than 5 Ma and form the final phase of intrusion in the Haramosh area and parts of the southern Karakoram area.

221 citations

Journal ArticleDOI
TL;DR: In this article, a provenance study of Neoproterozoic siliciclastic successions in the stratigraphically and tectonically lowermost and uppermost parts of the Pan-African Gariep Belt (Stinkfontein Subgroup and Oranjemund Group, respectively) in southwestern Africa, as well as in the Rocha Group of the Punta del Este Terrane (Dom Feliciano Belt) in Uruguay, revealed that the ORANJemund and rocha groups can be correlated and most

221 citations

Journal ArticleDOI
TL;DR: In this paper, five discrete accretionary events assembled fragments of continental and oceanic crust into a coherent Superior craton by 2.60 Ga. They exhibit similar sequences of events at 10 million year intervals: cessation of arc magmatism, early deformation, synorogenic sedimentation, bulk shortening, regional metamorphism, late transpression, orogenic gold localization, emplacement of crust derived granites, and postorogenic cooling.
Abstract: Five discrete accretionary events assembled fragments of continental and oceanic crust into a coherent Superior craton by 2.60 Ga. They exhibit similar sequences of events at 10 million year intervals: cessation of arc magmatism, early deformation, synorogenic sedimentation, sanukitoid magmatism, bulk shortening, regional metamorphism, late transpression, orogenic gold localization, emplacement of crust-derived granites, and postorogenic cooling. The Northern Superior superterrane recorded 3.7-2.75 Ga events prior to 2.72 Ga collision with the 3.0 Ga North Caribou superterrane. Following 2.98 Ga rifting, the Uchi margin of the North Caribou superterrane evolved in an upper plate setting before 2.72-2.70 Ga collision of the <3.4 Ga Winnipeg River terrane, which trapped synorogenic English River turbidites in the collision zone. The Winnipeg River terrane was reworked in 2.75-2.68 Ga magmatic and tectonic events, including the central Superior orogeny (2.71-2.70 Ga) that marks accretion of the juvenile western Wabigoon terrane. In the south, the Wawa-Abitibi terrane evolved in a mainly oceanic setting until Shebandowanian collision with the composite Superior superterrane at 2.695 Ga. Synorogenic Quetico turbidites were trapped in the collision zone. The final accretionary event involved addition of the Minnesota River Valley terrane (MRVT) from the south, and deposition and metamorphism of synorogenic turbidites of the Pontiac terrane during the 2.68 Ga Minnesotan orogeny. Seismic reflection and refraction images indicate north-dipping structures, interpreted as a stack of discrete 10-15 km thick terranes. A slab of high-velocity material, possibly representing subcreted oceanic lithosphere, as well as Moho offsets, support a model of progressive ac- cretion through plate-tectonic-like processes. Resume : Il y a 2,60 Ga, cinq evenements accretionnaires distincts ont rassemble des fragments de croute continentale et oceanique; le craton coherent du lac Superieur est le resultat de cette accretion. Ces fragments montrent des sequences d'evenements semblables, a des intervalles d'environ 10 Ma : la cessation du magmatisme d'arc, une deformation precoce, une sedimentation synorogenique, un magmatisme sanukitoide, un retrecissement en vrac, un metamorphisme regional, une transpression tardive, la localisation de l'or orogenique, la mise en place de granites derives de la croute et un refroi- dissement post-orogenique. Le superterrane du lac Superieur septentrional a enregistre des evenements de 3,7-2,75 Ga avant la collision a 2,72 Ga avec le superterrane de North Caribou de 3,0 Ga. A la suite de la distension il y a 2,98 Ga, la bordure de la sous-province d'Uchi du superterrane de North Caribou a evolue en un environnement de plaque supe- rieure avant la collision, 2,72-2,70 Ga, avec le terrane de Winnipeg River, <3,4 Ga, ce qui a piege les turbidites sy- norogeniques d'English River dans la zone de collision. Vers 2,75-2,68 Ga, le terrane de Winnipeg River a ete remaine lors d'evenements magmatiques et tectoniques, incluant l'orogene du centre de la Province du lac Superieur (2,71-2,70 Ga) qui marque l'accretion du terrane juvenile Wabigoon occidental. Vers le sud, le terrane de Wawa-Abitibi a evolue dans un environnement surtout oceanique jusqu'a sa collision au Shebandowanien avec le superterrane composite du lac Su- perieur a 2,695 Ga. Des turbidites synorogeniques de Quetico ont ete piegees dans la zone de collision. L'evenement accretionnaire final a implique l'ajout du terrane de Minnesota River Valley provenant du sud ainsi que la deposition et le metamorphisme de turbidites synorogeniques du terrane de Pontiac au cours de l'orogenese minnesotaine, 2,68 Ga. Les donnees de sismique reflexion et refraction indiquent des structures a pendage vers le nord qui sont interpretees comme un empilement de terranes distincts d'une epaisseur de 10-15 km. Une dalle de materiau a haute vitesse, repre- sentant possiblement une lithosphere oceanique accretee par le dessous, ainsi que des decalages du Moho, supportent un modele d'accretions progressives par des processus semblables a celui de la tectonique des plaques.

221 citations

Journal ArticleDOI
TL;DR: The tectonic settings for the formation and evolution of regional granulite terranes and the lowermost continental crust can be deduced from pressure-temperature-time (P-T-time) paths and constrained by petrological and geophysical considerations.
Abstract: The tectonic settings for the formation and evolution of regional granulite terranes and the lowermost continental crust can be deduced from pressure–temperature–time (P–T–time) paths and constrained by petrological and geophysical considerations. P–T conditions deduced for regional granulites require transient, average geothermal gradients of greater than 35°C km−1, implying minimum heat flow in excess of 100 mWm−2. Such high heat flow is probably caused by magmatic heating. Tectonic settings wherein such conditions are found include convergent plate margins, continental rifts, hot spots and at the margins of large, deep-seated batholiths. However, particular P–T–time paths do not allow specific tectonic settings to be distinguished at this time. Under different conditions, both clockwise, CW (Pmax attained before Tmax), and anticlockwise, ACW (Pmax attained slightly after Tmax), paths are possible in the same tectonic setting. Both CW and ACW end-member paths can yield nearly isobaric cooling, IBC, paths. Such cooling paths are clearly not an artefact of thermobarometry, but can be constrained by solid–solid and devolatilization equilibria and geophysical modelling. In terms of understanding the evolution of the deep crust, a potentially significant group of regional granulite terranes are those that show evidence for ACW-IBC paths. Such paths are the likely result of: (i) episodic igneous activity resulting in intrusions within all levels of the crust, (ii) thickening of the crust by magmatic underplating, (iii) slow uplift as a result of the formation of a deep, garnet-rich crustal root and (iv) excavation resulting from a later tectonic event unrelated to that resulting in the formation of the granulites. The later event might be triggered by the delamination of the garnet-rich, lowermost crust.

221 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023360
2022725
2021413
2020420
2019407
2018344