Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario
... overlying Huronian Supergroup (about 2450 Ma) to the south (Pye et al., 1984; Naldrett, 1999). The impact produced a crater some 200 km in diametre, as well as radiating and concentric fracture/breccia zones that penetrated the surrounding wall rocks for distances of tens of kilometres. The impact g ...
... overlying Huronian Supergroup (about 2450 Ma) to the south (Pye et al., 1984; Naldrett, 1999). The impact produced a crater some 200 km in diametre, as well as radiating and concentric fracture/breccia zones that penetrated the surrounding wall rocks for distances of tens of kilometres. The impact g ...
English - SciELO Colombia
... radioactive heat production per volume unit. Material parameters are assumed to remain constant within the major crustal and subcrustal layers, except for the heat production A, for which in some cases an exponential decay with depth is usually assumed. There are several processes that may affect th ...
... radioactive heat production per volume unit. Material parameters are assumed to remain constant within the major crustal and subcrustal layers, except for the heat production A, for which in some cases an exponential decay with depth is usually assumed. There are several processes that may affect th ...
Stratigraphy and Structure Canberra 1:50 000 Geological Map Area
... as about 65 metres; however, on Capital Hill it may be as much as 200 metres thick. At the southern foot of Black Mountain the thickness is about 50 metres if it is assumed that the shale rests unconformably on mudstone which Opik mapped as Pittman Formation; however, in a stratigraphic drill hole c ...
... as about 65 metres; however, on Capital Hill it may be as much as 200 metres thick. At the southern foot of Black Mountain the thickness is about 50 metres if it is assumed that the shale rests unconformably on mudstone which Opik mapped as Pittman Formation; however, in a stratigraphic drill hole c ...
IDOE Workshop on Tectonic Patterns and Metallogenesis in East
... 5.What proportion of sediments on a subducting plate is carried down to the subduction zone to be metamorphosed or consumed,and what proportion is scraped off and uplifted to be added to the outer arc islands such as those of the Indonesian archipelago (Mentawai Islands,Timor,etc.) ? Geologically th ...
... 5.What proportion of sediments on a subducting plate is carried down to the subduction zone to be metamorphosed or consumed,and what proportion is scraped off and uplifted to be added to the outer arc islands such as those of the Indonesian archipelago (Mentawai Islands,Timor,etc.) ? Geologically th ...
06_chapter 2
... The Archipelago Group represents the topmost stratigraphic unit of the Andaman accretionary prism. The deposition of this unit was believed to have taken place mostly in a slope environment (Roy, 1983). The lower members of this group comprise basal conglomerates and sandstones, overlain by calcareo ...
... The Archipelago Group represents the topmost stratigraphic unit of the Andaman accretionary prism. The deposition of this unit was believed to have taken place mostly in a slope environment (Roy, 1983). The lower members of this group comprise basal conglomerates and sandstones, overlain by calcareo ...
geologic map of the pocatello south quadrangle, bannock and
... or late Tertiary flow. Trimble (1976) inferred that the lava flowed into a valley cut along a fault contact. In fact, the upper contact is faulted and the unit is similar to Tsup1, suggesting that it is Miocene in age. Rhyolite porphyry, unit 1—Porphyritic rhyolite with about 20 percent phenocrysts ...
... or late Tertiary flow. Trimble (1976) inferred that the lava flowed into a valley cut along a fault contact. In fact, the upper contact is faulted and the unit is similar to Tsup1, suggesting that it is Miocene in age. Rhyolite porphyry, unit 1—Porphyritic rhyolite with about 20 percent phenocrysts ...
Seismic view on the svalbard passive continental margin
... velocity and the thinned continental crust in the continent-ocean transition zone. The evolution of this region appears to be within a shear-rift tectonic setting. The continent-ocean transition zone along the northernmost profile (99200) is mostly dominated by extension; therefore, the last stage o ...
... velocity and the thinned continental crust in the continent-ocean transition zone. The evolution of this region appears to be within a shear-rift tectonic setting. The continent-ocean transition zone along the northernmost profile (99200) is mostly dominated by extension; therefore, the last stage o ...
Spreading Continents Kick-Started Plate Tectonics Plate tectonics
... that no convective stresses act on the lid, allowing us to isolate the dynamic effect of the continent. A ...
... that no convective stresses act on the lid, allowing us to isolate the dynamic effect of the continent. A ...
Geology, Geochronology, and Hf and Pb Isotope Data of the Raúl
... allow the mapping of the Raúl-Condestable IOCG deposit in a nearly complete oblique cross section, from its associated volcanic edifice down to a paleodepth of about 6 km. U-Pb zircon ages indicate that in the deposit area felsic magmatic activity took place between 116.7 ± 0.4 and 114.5 ± 1 Ma, def ...
... allow the mapping of the Raúl-Condestable IOCG deposit in a nearly complete oblique cross section, from its associated volcanic edifice down to a paleodepth of about 6 km. U-Pb zircon ages indicate that in the deposit area felsic magmatic activity took place between 116.7 ± 0.4 and 114.5 ± 1 Ma, def ...
Plate boundaries, rifts and transforms in Iceland
... Crustal formation occurs by magmatism in zones of divergence. Most of the activity is linked with volcanic systems, about 25 of which have been identified on land and 10 more in the shelf areas to the north and south. A volcanic system is defined from its structural and petrologic characteristics (S ...
... Crustal formation occurs by magmatism in zones of divergence. Most of the activity is linked with volcanic systems, about 25 of which have been identified on land and 10 more in the shelf areas to the north and south. A volcanic system is defined from its structural and petrologic characteristics (S ...
93. Lee, C. - Squarespace
... at the surface are basalt-andesitic to andesitic and hence have higher Si contents. Endmember hypotheses for the origin of andesites are: (1) direct melting of the mantle at water-saturated conditions, (2) partial re-melting of altered basaltic crust, (3) crystal fractionation of arc basalts in crus ...
... at the surface are basalt-andesitic to andesitic and hence have higher Si contents. Endmember hypotheses for the origin of andesites are: (1) direct melting of the mantle at water-saturated conditions, (2) partial re-melting of altered basaltic crust, (3) crystal fractionation of arc basalts in crus ...
Practice Quiz for Ch. 15 Multiple Choice Identify the choice that best
... Indicate whether the statement is true or false. ____ 26. The earth's crust consists of continental crust and oceanic crust. ____ 27. Tectonic plates float on a sea of lava or molten rock. ____ 28. A subduction zone is associated with a transform fault. ____ 29. The United States, Canada, Russia, So ...
... Indicate whether the statement is true or false. ____ 26. The earth's crust consists of continental crust and oceanic crust. ____ 27. Tectonic plates float on a sea of lava or molten rock. ____ 28. A subduction zone is associated with a transform fault. ____ 29. The United States, Canada, Russia, So ...
SEDIMENTARY BASINS BASIN TYPES ACCORDING TO
... • Pannonian-type basins originate from postorogenic divergence between two foldthrust zones (Fig. 1.3a). They are usually associated with an A-subduction zone and are floored by thinning continental or transitional crust . ...
... • Pannonian-type basins originate from postorogenic divergence between two foldthrust zones (Fig. 1.3a). They are usually associated with an A-subduction zone and are floored by thinning continental or transitional crust . ...
A review of geological origins and relationships in the Ballantrae
... briefly noted the same comparison. However, though Bonney was correct in his petrographical assessment, he had little evidence as to the age of the rocks, and so related the lavas and agglomerates to the established Early Devonian volcanic episode of southern Scotland, with the serpentinite as a yo ...
... briefly noted the same comparison. However, though Bonney was correct in his petrographical assessment, he had little evidence as to the age of the rocks, and so related the lavas and agglomerates to the established Early Devonian volcanic episode of southern Scotland, with the serpentinite as a yo ...
Mineral Resources in the Eastern Alps and Adjoining Areas
... suture zone situated at the northern margin of Gondwana, from which they split off during the Cambrian-Ordovician and Silurian. Cambrian (?) rifting at the active Gondwana margin was interrupted by a short-lived Orodovician orogenic event. After terrane drifting to the north, the final Variscan coll ...
... suture zone situated at the northern margin of Gondwana, from which they split off during the Cambrian-Ordovician and Silurian. Cambrian (?) rifting at the active Gondwana margin was interrupted by a short-lived Orodovician orogenic event. After terrane drifting to the north, the final Variscan coll ...
Plate boundaries, rifts and transforms in Iceland
... Crustal formation occurs by magmatism in zones of divergence. Most of the activity is linked with volcanic systems, about 25 of which have been identified on land and 10 more in the shelf areas to the north and south. A volcanic system is defined from its structural and petrologic characteristics (S ...
... Crustal formation occurs by magmatism in zones of divergence. Most of the activity is linked with volcanic systems, about 25 of which have been identified on land and 10 more in the shelf areas to the north and south. A volcanic system is defined from its structural and petrologic characteristics (S ...
here - W. Steven Holbrook
... crust, as we discuss in the following. The interpretation of composition from seismic P-wave velocity is nonunique and affected by numerous factors such as pressure, temperature, and porosity. Nonetheless, given constraints on pressure and temperature and some reasonable assumptions, P-wave velociti ...
... crust, as we discuss in the following. The interpretation of composition from seismic P-wave velocity is nonunique and affected by numerous factors such as pressure, temperature, and porosity. Nonetheless, given constraints on pressure and temperature and some reasonable assumptions, P-wave velociti ...
Geoscientific Report GR2011-1
... the Flin Flon Belt (Inlet Arm Fault, Northeast Arm Fault). Several localities of felsic volcanic rocks in the NFFB may also be prospective for base-metal and/or precious-metal mineralization, based on their geochemical signature. The location of the Trout Lake mine at the inferred contact between th ...
... the Flin Flon Belt (Inlet Arm Fault, Northeast Arm Fault). Several localities of felsic volcanic rocks in the NFFB may also be prospective for base-metal and/or precious-metal mineralization, based on their geochemical signature. The location of the Trout Lake mine at the inferred contact between th ...
Pacific Beach San Diego
... times for southern California, as the Farallon plate was subducting underneath the North American plate, and volcanoes scorched the California interior. This was a period of mountain building and land reshaping. Much of present day California was submerged in the Pacific, teaming with crustaceans, a ...
... times for southern California, as the Farallon plate was subducting underneath the North American plate, and volcanoes scorched the California interior. This was a period of mountain building and land reshaping. Much of present day California was submerged in the Pacific, teaming with crustaceans, a ...
Linking rift propagation barriers to excess magmatism at volcanic
... delay controls the flow beneath the rift axis. During the first 5 m.y., extension of segment 1 is accompanied by dominantly vertical flow, until it comprises a reservoir of hot, low-viscosity mantle material. Following activation of the next segment at 5 m.y., parts of this low-viscosity mantle are ...
... delay controls the flow beneath the rift axis. During the first 5 m.y., extension of segment 1 is accompanied by dominantly vertical flow, until it comprises a reservoir of hot, low-viscosity mantle material. Following activation of the next segment at 5 m.y., parts of this low-viscosity mantle are ...
Deep Mantle Plumes and Geoscience Vision
... tens of meters, and propagate, at about the rate a person can walk, for hundreds of kilometers. In addition to dike swarms, which are usually mapped aeromagnetically, seismic reflection imaging has discovered extensive subhorizontal intrusive sheets in the mid-crust. Some are connected with the Mack ...
... tens of meters, and propagate, at about the rate a person can walk, for hundreds of kilometers. In addition to dike swarms, which are usually mapped aeromagnetically, seismic reflection imaging has discovered extensive subhorizontal intrusive sheets in the mid-crust. Some are connected with the Mack ...
Chapter 22 Evidence for Early and Mid
... et al. 1983). Other deformation resulted from pervasive left-lateral strike-slip shearing along the Najd fault system, which was active during Ediacaran time (Sultan et al. 1988). Najd deformation was a far-field manifestation of collision between fragments of east and west Gondwana (Abdelsalam & St ...
... et al. 1983). Other deformation resulted from pervasive left-lateral strike-slip shearing along the Najd fault system, which was active during Ediacaran time (Sultan et al. 1988). Najd deformation was a far-field manifestation of collision between fragments of east and west Gondwana (Abdelsalam & St ...
Late Precambrian Stratigraphy and Structure of the North
... thousand metres thick sequence of fluvial, shallow-marine, slope and base-of slope deposits followed by sediments of a large deltak system which then gave way to shore-zone terrigenous strata and, subordinately, carbonate deposits containing domal stromatolites. A fluvial regime was partly re-establ ...
... thousand metres thick sequence of fluvial, shallow-marine, slope and base-of slope deposits followed by sediments of a large deltak system which then gave way to shore-zone terrigenous strata and, subordinately, carbonate deposits containing domal stromatolites. A fluvial regime was partly re-establ ...
Geologic Map and Cross Sections of the Embudo Fault Zone in the
... he southern Taos Valley encompasses the physiographic and geologic transition zone between the Picuris Mountains and the San Luis Basin of the Rio Grande rift. The Embudo fault zone is the rift transfer structure that has accommodated the kinematic disparities between the San Luis Basin and the Espa ...
... he southern Taos Valley encompasses the physiographic and geologic transition zone between the Picuris Mountains and the San Luis Basin of the Rio Grande rift. The Embudo fault zone is the rift transfer structure that has accommodated the kinematic disparities between the San Luis Basin and the Espa ...
Carbonatite occurrences of the world: map and database, by AR
... started listing alkaline rocks and carbonatites along with their ages, spatial distribution, and associated rocks types in his volume on the carbonatites of North and South America that appeared in 1987. Since then, other volumes have appeared with Woolley acting as the main driving force. These vol ...
... started listing alkaline rocks and carbonatites along with their ages, spatial distribution, and associated rocks types in his volume on the carbonatites of North and South America that appeared in 1987. Since then, other volumes have appeared with Woolley acting as the main driving force. These vol ...
Algoman orogeny
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 Archaen 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 Canadian shield contains belts of metavolcanic and metasedimentary rocks formed by the action of metamorphism on volcanic and sedimentary rock. The areas between individual belts consist of granites or granitic gneisses that form fault zones. These two types of belts can be seen in the Wabigoon, Quetico and Wawa subprovinces; the Wabigoon and Wawa are of volcanic origin and the Quetico is of sedimentary origin. These three subprovinces lie linearly in southwestern- to northeastern-oriented belts about 140 km (90 mi) wide on the southern portion of the Superior Province.The Slave province and portions of the Nain province were also affected. Between about 2,000 and 1,700 million years ago these combined with the Sask and Wyoming cratons to form the first supercontinent, the Kenorland supercontinent.