What drives microplate motion and deformation in the northeastern
... at its eastern and western plate boundaries, and by transpressional shear systems at its northern and southern boundaries [Molnar and Sykes, 1969]. The tectonics of the northern plate boundary zone (Figure 1), which separates the Caribbean plate from the North America plate, are diverse and complica ...
... at its eastern and western plate boundaries, and by transpressional shear systems at its northern and southern boundaries [Molnar and Sykes, 1969]. The tectonics of the northern plate boundary zone (Figure 1), which separates the Caribbean plate from the North America plate, are diverse and complica ...
Landslides in Eastern Honshu Induced by the 2011 Off the Pacific
... where the Pacific plate subducts below the North American plate at the relatively high rate of 10 cm=year (Hasegawa et al., 2000). The crust of Honshu was initially generated by Paleozoic to Mesozoic accretionary processes, and later by voluminous intrusion of granitic rocks during the late Cretaceo ...
... where the Pacific plate subducts below the North American plate at the relatively high rate of 10 cm=year (Hasegawa et al., 2000). The crust of Honshu was initially generated by Paleozoic to Mesozoic accretionary processes, and later by voluminous intrusion of granitic rocks during the late Cretaceo ...
1 Origin and geodynamic relationships of the Late Miocene to
... plume or plume fingers beneath this region. Instead, we propose that plate tectonic processes ...
... plume or plume fingers beneath this region. Instead, we propose that plate tectonic processes ...
Initiation of Subduction Zones as a Consequence
... respect to the asthenosphere. Therefore, it would be physically optimal if one part of the lithosphere experienced a greater gravitational attraction than its adjacent neighbour before or during the initiation of a subduction zone. This requires the pre-existence of a density contrast within the lit ...
... respect to the asthenosphere. Therefore, it would be physically optimal if one part of the lithosphere experienced a greater gravitational attraction than its adjacent neighbour before or during the initiation of a subduction zone. This requires the pre-existence of a density contrast within the lit ...
Experimental Constraints on TTG Petrogenesis: Implications
... and hornblende (commonly). Small amounts of K-feldspar are occasionally found. Accessory minerals are typically epidote, allanite, sphene, zircon, magnetite, and ilmenite. In terms of chemistry, TTGs are sodic granitoids, with molecular K/Na ratios below 0.4 and SiO2 content between 65 and 75 wt%. M ...
... and hornblende (commonly). Small amounts of K-feldspar are occasionally found. Accessory minerals are typically epidote, allanite, sphene, zircon, magnetite, and ilmenite. In terms of chemistry, TTGs are sodic granitoids, with molecular K/Na ratios below 0.4 and SiO2 content between 65 and 75 wt%. M ...
The West Philippine Basin: An Eocene to early Oligocene back arc
... the NW – SE orientation of the rift valley and its associated steep escarpments, which are related to large normal faults (Figures 4, 5, and 8). This episode was probably brief since abyssal hills that parallel the axial valley are found only within a very narrow strip of seafloor on both sides of t ...
... the NW – SE orientation of the rift valley and its associated steep escarpments, which are related to large normal faults (Figures 4, 5, and 8). This episode was probably brief since abyssal hills that parallel the axial valley are found only within a very narrow strip of seafloor on both sides of t ...
OPAQUE OXIDES IN SOME ROCKS OF THE BASEMENT
... Pyrrhotite, pyrite, and chalcopyrite occur in the Afua gabbro as small, isolatedgrains averaging0.04X0.08 mm. in size. Matapau. Minor amounts of small crystals of primary magnetite, chalcopyrite, and pyrrhotite are present in a hornblende-augite-hypersthene-olivinegabbro from Matapau. The magnetite ...
... Pyrrhotite, pyrite, and chalcopyrite occur in the Afua gabbro as small, isolatedgrains averaging0.04X0.08 mm. in size. Matapau. Minor amounts of small crystals of primary magnetite, chalcopyrite, and pyrrhotite are present in a hornblende-augite-hypersthene-olivinegabbro from Matapau. The magnetite ...
iceland in relation to the mid-atlantic ridge
... meters in the Reykjanes thermal area show that this formation, seismically determined to be about 900 meters thick, consists there mainly of hyaloclastic tuffs and breccias and tuffaceous sediments, with basalt lavas as a minor component (13,112). These rocks are believed to have been erupted under ...
... meters in the Reykjanes thermal area show that this formation, seismically determined to be about 900 meters thick, consists there mainly of hyaloclastic tuffs and breccias and tuffaceous sediments, with basalt lavas as a minor component (13,112). These rocks are believed to have been erupted under ...
Depth distribution of Moho and tectonic framework in eastern Asian
... volcano, and earthquake, as well as tectonics, is discussed. According to the outline map of distribution of Moho discontinuity from the data of seismic sounding profiles carried out before 1990[14], China continent is divided into 8 blocks[11,14]. The above-mentioned Moho depth maps compiled based ...
... volcano, and earthquake, as well as tectonics, is discussed. According to the outline map of distribution of Moho discontinuity from the data of seismic sounding profiles carried out before 1990[14], China continent is divided into 8 blocks[11,14]. The above-mentioned Moho depth maps compiled based ...
Geological Survey of Denmark and Greenland Map Series 2
... basin, half-grabens, basic intrusions, economic geology. Cover Extract of the central part of the Thule map sheet (Steensby Land) within the Proterozoic Thule Basin. The Thule Supergroup (Nares Strait Group (N), Baffin Bay Group (B, Bw, Bq), Dundas Group (D, Do)) overlies Archaean shield (Thule mixe ...
... basin, half-grabens, basic intrusions, economic geology. Cover Extract of the central part of the Thule map sheet (Steensby Land) within the Proterozoic Thule Basin. The Thule Supergroup (Nares Strait Group (N), Baffin Bay Group (B, Bw, Bq), Dundas Group (D, Do)) overlies Archaean shield (Thule mixe ...
The Model of Oceanic Crust Expansion
... In the formula, V refers to the incremental quantity of the volume of the earth’s mantle in the phase of expansion; Tv refers to the state variant of the solid matters within the earth in the phase of expansion; 0.097 refers to the comprehensive volume changing coefficient of the earth’s matters (15 ...
... In the formula, V refers to the incremental quantity of the volume of the earth’s mantle in the phase of expansion; Tv refers to the state variant of the solid matters within the earth in the phase of expansion; 0.097 refers to the comprehensive volume changing coefficient of the earth’s matters (15 ...
Cedar Butte and Cogenetic Quaternary Rhyolite Domes of the
... Butte. Spear (1979) also notes disequilibrium phenocryst assemblages and textures in similar enclaves elsewhere in the dome. He interpreted the enclaves as hybrid inclusions produced by mixing of partially crystallized mafic magma with the host rhyolite. However, most of the enclaves vary from ang ...
... Butte. Spear (1979) also notes disequilibrium phenocryst assemblages and textures in similar enclaves elsewhere in the dome. He interpreted the enclaves as hybrid inclusions produced by mixing of partially crystallized mafic magma with the host rhyolite. However, most of the enclaves vary from ang ...
Old Red Sandstone Rocks of Great Britain
... 1977) now places the basal parts of the Old Red Sandstone in the modern Silurian System. The strata from the Ludlow Bone Bed up to the base of the modern Devonian System, which is as yet poorly defined in the Old Red Sandstone, belong to the PÍídolí Series, the fourth, uppermost series of the Siluri ...
... 1977) now places the basal parts of the Old Red Sandstone in the modern Silurian System. The strata from the Ludlow Bone Bed up to the base of the modern Devonian System, which is as yet poorly defined in the Old Red Sandstone, belong to the PÍídolí Series, the fourth, uppermost series of the Siluri ...
Mantle-driven deformation of orogenic zones and clutch tectonics
... two quasi-orthogonal waves that travel at different speeds (see reviews by Silver 1996; Savage 1999). The time lag between the two waves is controlled by the intrinsic anisotropy of the medium, which depends on the intensity of the lattice preferred orientations, and by the thickness of the anisotro ...
... two quasi-orthogonal waves that travel at different speeds (see reviews by Silver 1996; Savage 1999). The time lag between the two waves is controlled by the intrinsic anisotropy of the medium, which depends on the intensity of the lattice preferred orientations, and by the thickness of the anisotro ...
Physics and Chemistry of Deep Continental Crust
... these mechanisms operate. However, some aspects of the debate are premature: the first-order issue of when and where these processes operate has yet to be resolved. Furthermore, many of these terms imply very specific mechanisms of convective removal, but they are often used too casually to be effec ...
... these mechanisms operate. However, some aspects of the debate are premature: the first-order issue of when and where these processes operate has yet to be resolved. Furthermore, many of these terms imply very specific mechanisms of convective removal, but they are often used too casually to be effec ...
Tracing the evolving flux from the subducting plate in the Tonga
... Langmuir (1993) and Johnson and Plank (1999), suggested that the REE characteristics of many arc lavas are derived from the sediments being subducted in the adjacent trench. In the Marianas a relative negative anomaly in Ce seen in the lavas from Agrigan Island was compared with a negative Ce anomal ...
... Langmuir (1993) and Johnson and Plank (1999), suggested that the REE characteristics of many arc lavas are derived from the sediments being subducted in the adjacent trench. In the Marianas a relative negative anomaly in Ce seen in the lavas from Agrigan Island was compared with a negative Ce anomal ...
Fall 2012 - Washtenaw Community College
... 10. Explain the difference between magma and lava, intrusive rocks and extrusive rocks, plutonic rocks and volcanic rocks. Matched Outcomes 11. Describe how the rate of cooling influences the size of crystals in igneous rocks. Matched Outcomes 12. Identify the different igneous rock textures (aphani ...
... 10. Explain the difference between magma and lava, intrusive rocks and extrusive rocks, plutonic rocks and volcanic rocks. Matched Outcomes 11. Describe how the rate of cooling influences the size of crystals in igneous rocks. Matched Outcomes 12. Identify the different igneous rock textures (aphani ...
compositional and thermal differences between lithospheric and
... Institute of the Earth’s Crust, Siberian Branch of RAS, Irkutsk, Russia Abstract: The lower part of lithosphere in collisional orogens may delaminate due to density inversion between the asthenosphere and the cold thickened lithospheric mantle. Generally, standard delamination models have neglected ...
... Institute of the Earth’s Crust, Siberian Branch of RAS, Irkutsk, Russia Abstract: The lower part of lithosphere in collisional orogens may delaminate due to density inversion between the asthenosphere and the cold thickened lithospheric mantle. Generally, standard delamination models have neglected ...
SILURIAN CLIFFS
... bedrock by waves. In the West Estonian Archipelago, cliffs occur on the northern coast of Kesselaid and Kõinastu islets, Muhu and Vilsandi islands, and the eastern, northern, and western coast of Saaremaa Island. The appearance of cliffs may differ: some rise as vertical walls, some are dissected by ...
... bedrock by waves. In the West Estonian Archipelago, cliffs occur on the northern coast of Kesselaid and Kõinastu islets, Muhu and Vilsandi islands, and the eastern, northern, and western coast of Saaremaa Island. The appearance of cliffs may differ: some rise as vertical walls, some are dissected by ...
Rhenium^Osmium Isotope and Platinum-Group Element
... anomaly studies show the intrusion extends northward for at least 250 km under younger cover where it becomes more laterally extensive (Fig. 1). The present exposure probably represents a thin, oblique slice through a much larger intrusion (Francis, 1994), with an estimated original volume in excess ...
... anomaly studies show the intrusion extends northward for at least 250 km under younger cover where it becomes more laterally extensive (Fig. 1). The present exposure probably represents a thin, oblique slice through a much larger intrusion (Francis, 1994), with an estimated original volume in excess ...
Fast-decaying IP in frozen unconsolidated rocks and potentialities
... the distribution of frozen ground and to estimate its temperature and ice content. Geoelectrical methods have an advantage in the study of the cryolithosphere due to the difference between the electrical properties of thawed and frozen rocks and due to the dependence of these properties on the tempe ...
... the distribution of frozen ground and to estimate its temperature and ice content. Geoelectrical methods have an advantage in the study of the cryolithosphere due to the difference between the electrical properties of thawed and frozen rocks and due to the dependence of these properties on the tempe ...
AZU_TD_BOX306_E9791_
... The major Late Cenozoic structural trends which in fluenced the formation of the Holocene physiography of west-central New M e x i c o ............................ Major physiographic features within the Colorado Pla teau and the Rio Grande graben of west-central New ...
... The major Late Cenozoic structural trends which in fluenced the formation of the Holocene physiography of west-central New M e x i c o ............................ Major physiographic features within the Colorado Pla teau and the Rio Grande graben of west-central New ...
Tectonostratigraphic Succession and Development of the
... with time. In the Seiland province, in terms of deformation episodes the oldest intrusions were emplaced during Di at 548 m.y. ago while late-D2 alkaline rocks date to ca. 500 m.y. B.P. Finnmarkian deformation was thus a protracted event spanning Upper Cambrian to Lower (or even Middle) Ordovician t ...
... with time. In the Seiland province, in terms of deformation episodes the oldest intrusions were emplaced during Di at 548 m.y. ago while late-D2 alkaline rocks date to ca. 500 m.y. B.P. Finnmarkian deformation was thus a protracted event spanning Upper Cambrian to Lower (or even Middle) Ordovician t ...
Leseane_okstate_0664M_13248
... x 1o. We found out that the Curie Point Depth (CPD) estimates vary between ~7 and ~23 km. The deepest CPD values (16 to 23 km) occur within the cratons which have lithospheric thickness greater than 200 km. Within the orogenic mobile belts, the CPD estimates range between 15 and 17 km. The shallowes ...
... x 1o. We found out that the Curie Point Depth (CPD) estimates vary between ~7 and ~23 km. The deepest CPD values (16 to 23 km) occur within the cratons which have lithospheric thickness greater than 200 km. Within the orogenic mobile belts, the CPD estimates range between 15 and 17 km. The shallowes ...
Class worksheet for Chapter 5: An Introduction to
... 14. Imagine you are sitting beside a campfire, roasting a sausage on an iron skewer. Describe the heat transfer processes in a practical sense with respect to your fire. ...
... 14. Imagine you are sitting beside a campfire, roasting a sausage on an iron skewer. Describe the heat transfer processes in a practical sense with respect to your fire. ...
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.