geology and chromite deposits of the camaguey district camaguey
... A series of volcanic rocks with interbedded limestones and radiolarian cherts lies unconformably on the serpentine. The volcanic sequence is composed primarily of water-laid andesitic tuffs, associated with lesser amounts of amygdaloidal lava, felsite, andesite porphyry, diabase, and basalt. The sed ...
... A series of volcanic rocks with interbedded limestones and radiolarian cherts lies unconformably on the serpentine. The volcanic sequence is composed primarily of water-laid andesitic tuffs, associated with lesser amounts of amygdaloidal lava, felsite, andesite porphyry, diabase, and basalt. The sed ...
Mineral Deposit Research: Meeting the Global Challenge
... against the latitude (Fig. 2) that illustrates north-south variation of numbers of deposits. The maximum number of deposits occur at around 48° N. To the north of this point, the number of deposit decreases steeply. The northern area is covered by stable platform sediments, and the small number of t ...
... against the latitude (Fig. 2) that illustrates north-south variation of numbers of deposits. The maximum number of deposits occur at around 48° N. To the north of this point, the number of deposit decreases steeply. The northern area is covered by stable platform sediments, and the small number of t ...
Field Trip Guide
... rocks that have not been significantly transported from their site of formation/deposition) in New York by a major unnamed fault that lies beneath Lake Champlain. In the autochthon, Mesoproterozic metamorphic rocks of the Adirondack Massif are unconformably overlain by sedimentary rocks of the Beekm ...
... rocks that have not been significantly transported from their site of formation/deposition) in New York by a major unnamed fault that lies beneath Lake Champlain. In the autochthon, Mesoproterozic metamorphic rocks of the Adirondack Massif are unconformably overlain by sedimentary rocks of the Beekm ...
53 Al – Aluminium
... gibbsite, nordstrandite and bayerite, which may control the equilibrium concentration of Al in soil solution, groundwater and stream water. In tropical conditions, weathering may produce the Al-ore bauxite, a mixture of several secondary hydroxide/oxide minerals. Aluminium is present at percent leve ...
... gibbsite, nordstrandite and bayerite, which may control the equilibrium concentration of Al in soil solution, groundwater and stream water. In tropical conditions, weathering may produce the Al-ore bauxite, a mixture of several secondary hydroxide/oxide minerals. Aluminium is present at percent leve ...
Arc-Continent collision in Taiwan: New marine observations and
... as suggested by the Neogene age of associated volcanism along the Luzon Arc (Ho, 1986). The Manila accretionary wedge has developed between the two plates (Fig. 1) and is still growing today south of 21°20'N (Hayes and Lewis, 1984 ; Lewis and Hayes, 1983, 1984 ; 1989). North of 21°20'N, the wedge be ...
... as suggested by the Neogene age of associated volcanism along the Luzon Arc (Ho, 1986). The Manila accretionary wedge has developed between the two plates (Fig. 1) and is still growing today south of 21°20'N (Hayes and Lewis, 1984 ; Lewis and Hayes, 1983, 1984 ; 1989). North of 21°20'N, the wedge be ...
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... the outer edge of the slope as indicating deformationwhich is continuous up to the present. Both von Heune and Kulm (1973) and Scho11(1974)also deduce that there is good evidence of very recent deformation and uplift in response to compression at the Washington-Oregon slope. Von Heune and Kulm compu ...
... the outer edge of the slope as indicating deformationwhich is continuous up to the present. Both von Heune and Kulm (1973) and Scho11(1974)also deduce that there is good evidence of very recent deformation and uplift in response to compression at the Washington-Oregon slope. Von Heune and Kulm compu ...
THE SIGNIFICANCE OF THE METAMORPHIC ROCKS OF TIMOR
... slate. Among the amphibolite facies gneiss, metapelite with kyanite (Valk, 1945) or cordierite (Germeraad, 1946) have been recorded, indicating that both high- and low-pressure metamorphic terrains are present. ...
... slate. Among the amphibolite facies gneiss, metapelite with kyanite (Valk, 1945) or cordierite (Germeraad, 1946) have been recorded, indicating that both high- and low-pressure metamorphic terrains are present. ...
Department of Natural Resources
... New mapping and geochronological studies of the central Avalon Peninsula reveal a geological record of protracted and episodic volcanicity, having varied composition, lithofacies, and depositional environments, spanning a period of 160 Ma in the late Neoproterozoic. Deposition of these disparate vol ...
... New mapping and geochronological studies of the central Avalon Peninsula reveal a geological record of protracted and episodic volcanicity, having varied composition, lithofacies, and depositional environments, spanning a period of 160 Ma in the late Neoproterozoic. Deposition of these disparate vol ...
Age and tectonic setting of the Tysfjord gneiss granite, Efjord, North
... tact relationships interpreted as intrusive contacts have been observed. In such cases the gneiss gra nite appears to be the younger. Most of the mafic gneisses are now biotite schists and/or gneisses, but relict amphiboles suggest they were amphi bolites prior to the (?) Caledonian deformation or ...
... tact relationships interpreted as intrusive contacts have been observed. In such cases the gneiss gra nite appears to be the younger. Most of the mafic gneisses are now biotite schists and/or gneisses, but relict amphiboles suggest they were amphi bolites prior to the (?) Caledonian deformation or ...
On the influence of the asthenospheric flow on the tectonics and
... 2001; Zhang et al., 2004) is also ascribed to body forces due to high elevations (England and Houseman, 1986; England and Molnar, 1997; Flesch et al., 2001; Liu and Yang, 2003; Flesch et al., 2005). It is not clear, however, whether a gravitationally driven flow would coherently affect the deformatio ...
... 2001; Zhang et al., 2004) is also ascribed to body forces due to high elevations (England and Houseman, 1986; England and Molnar, 1997; Flesch et al., 2001; Liu and Yang, 2003; Flesch et al., 2005). It is not clear, however, whether a gravitationally driven flow would coherently affect the deformatio ...
Lithospheric layering in the North American craton
... How cratons—extremely stable continental areas of the Earth’s crust—formed and remained largely unchanged for more than 2,500 million years is much debated. Recent studies of seismic-wave receiver function data have detected a structural boundary under continental cratons at depths too shallow to be ...
... How cratons—extremely stable continental areas of the Earth’s crust—formed and remained largely unchanged for more than 2,500 million years is much debated. Recent studies of seismic-wave receiver function data have detected a structural boundary under continental cratons at depths too shallow to be ...
Understanding the thermal evolution of deep
... little evidence for magmatism until new oceanic crust has formed16. The best-studied margin occurs west of the Iberian Peninsula17, but this type of margin is more widespread than ‘hot’ ones (Figs 2, 3c). As before, crustal thickness decreases from 30 km to less than 5 km over a distance of ~200 km. ...
... little evidence for magmatism until new oceanic crust has formed16. The best-studied margin occurs west of the Iberian Peninsula17, but this type of margin is more widespread than ‘hot’ ones (Figs 2, 3c). As before, crustal thickness decreases from 30 km to less than 5 km over a distance of ~200 km. ...
10. METAMORPHOSED SEDIMENTARY (VOLCANICLASTIC
... m of Paleocene basalt and interlayered dacite that comprise the dipping seismic reflectors along the southeast Greenland margin, and thence into about 53.7 m of steeply dipping and metamorphosed sandstone and siltstone. Ten centimeters of quartz sandstone, probably of fluvial origin, was recovered b ...
... m of Paleocene basalt and interlayered dacite that comprise the dipping seismic reflectors along the southeast Greenland margin, and thence into about 53.7 m of steeply dipping and metamorphosed sandstone and siltstone. Ten centimeters of quartz sandstone, probably of fluvial origin, was recovered b ...
Re^Os evidence for replacement of ancient mantle
... craton (west of the major gravity lineament) formed during the last major Precambrian orogeny, around 1900 Ma ago. This age is significantly younger than the overlying crust (2700 Ma), suggesting that the original Archean lithosphere was replaced in the Proterozoic. The timing of lithospheric replac ...
... craton (west of the major gravity lineament) formed during the last major Precambrian orogeny, around 1900 Ma ago. This age is significantly younger than the overlying crust (2700 Ma), suggesting that the original Archean lithosphere was replaced in the Proterozoic. The timing of lithospheric replac ...
Paleozoic stratigraphy, tectonics and metallogeny
... of the Cassiar terrane into five depositional sequences within the Quiet Lake and Finlayson Lake map areas, which from oldest to youngest comprise the Ketza, Kechika, Askin, Harvey and Seagull groups. TempelmanKluit (2012) concluded that many of these depositional sequences likely correlate with age ...
... of the Cassiar terrane into five depositional sequences within the Quiet Lake and Finlayson Lake map areas, which from oldest to youngest comprise the Ketza, Kechika, Askin, Harvey and Seagull groups. TempelmanKluit (2012) concluded that many of these depositional sequences likely correlate with age ...
Geological Society of Malaysia Bulletin 49
... The folds and faults seen onshore Kudat Peninsula appear to be part of a larger structural feature in the northern Sabah region. It is quite possible that the style of deformation onshore Kudat Peninsula may well continue offshore (see Fig. 2) and has affected younger structures. This would imply th ...
... The folds and faults seen onshore Kudat Peninsula appear to be part of a larger structural feature in the northern Sabah region. It is quite possible that the style of deformation onshore Kudat Peninsula may well continue offshore (see Fig. 2) and has affected younger structures. This would imply th ...
A Dynamic Model of Rifting Between Galicia Bank and Flemish Cap
... 2001a; Russell and Whitmarsh, 2003). Assuming symmetric spreading, this corresponds to a whole-extension rate of 20 mm/yr during rifting. This is consistent with area balancing of the cross section in Fig. 2. Restoration of the cross section to a uniform crust thickness of 32 km requires an extensi ...
... 2001a; Russell and Whitmarsh, 2003). Assuming symmetric spreading, this corresponds to a whole-extension rate of 20 mm/yr during rifting. This is consistent with area balancing of the cross section in Fig. 2. Restoration of the cross section to a uniform crust thickness of 32 km requires an extensi ...
Clutch tectonics and the partial attachment of lithospheric layers
... the necessarily different displacement fields of rheologicallydistinct lithospheric layers. In contrast to detachment zones, these sub-horizontal shear zones act as partial attachment zones between lithospheric layers. Two cases are possible: 1) Top-driven clutch systems, such as in extensional core ...
... the necessarily different displacement fields of rheologicallydistinct lithospheric layers. In contrast to detachment zones, these sub-horizontal shear zones act as partial attachment zones between lithospheric layers. Two cases are possible: 1) Top-driven clutch systems, such as in extensional core ...
Bresse Graben System, European Crust and Topo Europe
... determined precisely as the seismic velocities of the crust and the mantle differ significantly. The boundary between the crust and the upper mantle is known as the Mohorovičić (henceforth referred to as Moho) discontinuity. The depth of this boundary between the mantle and the European crust varies ...
... determined precisely as the seismic velocities of the crust and the mantle differ significantly. The boundary between the crust and the upper mantle is known as the Mohorovičić (henceforth referred to as Moho) discontinuity. The depth of this boundary between the mantle and the European crust varies ...
Nappes of the southern Tien Shan
... prism was formed during a long-term interval. In the Moscovian after the closure of the Turkestan oceanic basin and during the collision of the Alay-Tarim and Kazakh–Kyrgyz terranes the accretionary prism rocks were overthrusted onto the Alay-Tarim continental margin. The oceanic crust subduction wa ...
... prism was formed during a long-term interval. In the Moscovian after the closure of the Turkestan oceanic basin and during the collision of the Alay-Tarim and Kazakh–Kyrgyz terranes the accretionary prism rocks were overthrusted onto the Alay-Tarim continental margin. The oceanic crust subduction wa ...
Subduction of oceanic lithosphere
... New crust is formed in marginal basins, island arcs, and oceanic plateaux New crust is accreted to the continents along the active continental margins. Crust is also added by magmatic underplating Continental crust is deformed in collision zones. It is eroded and recycled in the mantle in subduction ...
... New crust is formed in marginal basins, island arcs, and oceanic plateaux New crust is accreted to the continents along the active continental margins. Crust is also added by magmatic underplating Continental crust is deformed in collision zones. It is eroded and recycled in the mantle in subduction ...
Plateau uplift in western Canada caused by lithospheric
... of this process are debated, with proposed mechanisms ranging from delamination of fragments to that of the entire lithosphere1–4 . The Canadian Cordillera is an exhumed ancient plateau that abuts the North American Craton5 . The region experienced rapid uplift during the mid-to-late Eocene, followe ...
... of this process are debated, with proposed mechanisms ranging from delamination of fragments to that of the entire lithosphere1–4 . The Canadian Cordillera is an exhumed ancient plateau that abuts the North American Craton5 . The region experienced rapid uplift during the mid-to-late Eocene, followe ...
Evolution of the Paleo-Asian Ocean (Altai−Sayan Region, Central
... Study of the above-noted geodynamic units, which are best observed in the Katun (Cental Altai) and Kurai (East Altai) zones, made possible the reconstruction of paleogeodynamic processes (subduction and accretion), which seem to be similar to those in the western part of the Pacific active margin (W ...
... Study of the above-noted geodynamic units, which are best observed in the Katun (Cental Altai) and Kurai (East Altai) zones, made possible the reconstruction of paleogeodynamic processes (subduction and accretion), which seem to be similar to those in the western part of the Pacific active margin (W ...
Lithostratigraphic and tectonic framework of Jurassic
... Abstract: The south-central Intermontane belt of British Columbia has a complex architecture comprising late Paleozoic to Mesozoic volcanic and plutonic arc magmatic suites, marine and nonmarine clastic basins, high-grade metamorphic complexes, and accretionary rocks. Jurassic and Cretaceous clastic ...
... Abstract: The south-central Intermontane belt of British Columbia has a complex architecture comprising late Paleozoic to Mesozoic volcanic and plutonic arc magmatic suites, marine and nonmarine clastic basins, high-grade metamorphic complexes, and accretionary rocks. Jurassic and Cretaceous clastic ...
South coast of Arran
... reversed magnetization (>75%) and that the proportion showing reversed polarity increased from west to east. There is no simple correlation between polarity and petrography and neither is there a significant difference between mean pole directions of the alkali-basalt and tholeiitic intrusions. Over ...
... reversed magnetization (>75%) and that the proportion showing reversed polarity increased from west to east. There is no simple correlation between polarity and petrography and neither is there a significant difference between mean pole directions of the alkali-basalt and tholeiitic intrusions. Over ...
Great Lakes tectonic zone
The Great Lakes tectonic zone is bounded by South Dakota at its tip and heads northeast to south of Duluth, Minnesota, then heads east through northern Wisconsin, Marquette, Michigan, and then trends more northeasterly to skim the northern-most shores of lakes Michigan and Huron before ending in the Sudbury, Ontario, Canada, area.During the Late Archean Era the Algoman orogeny added landmass to the Superior province by volcanic activity and continental collision along a boundary that stretches from present-day South Dakota, U.S., into the Lake Huron region near Sudbury, Ontario, Canada.This crustal boundary is the Great Lakes tectonic zone. It is 1,400 km (870 mi) long, and separates the older Archean gneissic terrane to the south from younger Late Archean greenstone-granite terrane to the north.The zone is characterized by active compression during the Algoman orogeny (about 2,700 million years ago), a pulling-apart (extensional) tectonics (2,450 to 2,100 million years ago), a second compression during the Penokean orogeny (1,900 to 1,850 million years ago), a second extension during Middle Proterozoic time (1,600 million years ago) and minor reactivation during Phanerozoic time (the past 500 million years).Collision began along the Great Lakes tectonic zone (GLTZ) with the Algoman mountain-building event and continued for tens of millions of years. During the formation of the GLTZ, the gneissic Minnesota River Valley subprovince was thrust up onto the Superior province's edge as it consumed the Superior province's oceanic crust. Fragmentation of the Kenorland supercontinent began 2,450 million years ago and was completed by 2,100 million years ago. The Wyoming province is the continental landmass that is hypothesized to have rifted away from the southern Superior province portion of Kenorland, before moving rapidly west and docking with the Laurentia supercontinent 1,850 to 1,715 million years ago. Sedimentation from the GLTZ-rifting environment continued into the Penokean orogeny, which is the next major tectonic event in the Great Lakes region. Several earthquakes have been documented in Minnesota, Michigan's Upper Peninsula and Sudbury in the last 120 years along the GLTZ.