2200 million years of crustal evolution: the baltic shield
... seems to be well justified for the Sodankylä and Jauratsi greenstone belts, where supracrustals are intruded by the mafic layered complex of Koitelainen dated by the U-Pb method on zircons as 2450 Ma old (Kouvo 1976; Simonen 1980). These supracrustals form a typical Archean association with extensiv ...
... seems to be well justified for the Sodankylä and Jauratsi greenstone belts, where supracrustals are intruded by the mafic layered complex of Koitelainen dated by the U-Pb method on zircons as 2450 Ma old (Kouvo 1976; Simonen 1980). These supracrustals form a typical Archean association with extensiv ...
plate_tectonics302b
... • major continental collisions in central Asia • Australian-SE Asian collisions ...
... • major continental collisions in central Asia • Australian-SE Asian collisions ...
331 G
... ametamorphic or contact aureole. Outside of the contact aureole, the rocks are not affected by the intrusive event. The grade of metamorphism increases in all directions toward the intrusion. Because the temperature contrast between the surrounding rock and the intruded magma is larger at shallow le ...
... ametamorphic or contact aureole. Outside of the contact aureole, the rocks are not affected by the intrusive event. The grade of metamorphism increases in all directions toward the intrusion. Because the temperature contrast between the surrounding rock and the intruded magma is larger at shallow le ...
Powerpoint Presentation Physical Geology, 10/e
... Felsic (silicic) rocks have >65% silica, by weight, and contain lightcolored minerals that are abundant in silica, aluminum, sodium and ...
... Felsic (silicic) rocks have >65% silica, by weight, and contain lightcolored minerals that are abundant in silica, aluminum, sodium and ...
diverse intrusive and volcanic rocks in the axis of the abandoned
... rhyolite is its parallel REE pattern with that of the granite and the typical gabbro. This implies either 1) a common source among the intrusive units; or 2) fractionation from the gabbro to the rhyolite, although the lack of exposed intermediate units argues against fractionation. The continual geo ...
... rhyolite is its parallel REE pattern with that of the granite and the typical gabbro. This implies either 1) a common source among the intrusive units; or 2) fractionation from the gabbro to the rhyolite, although the lack of exposed intermediate units argues against fractionation. The continual geo ...
Evolution of the Helvetic Continental margin paper - RWTH
... processes that were present during the breaking apart of the ancient Pangaean continent. By splitting apart a lot of different zones of sedimentation were created which were for example deep ocean basins, shallow marginal seas and barrier zones. In the late Triassic 230 M years ago, the Pangaean con ...
... processes that were present during the breaking apart of the ancient Pangaean continent. By splitting apart a lot of different zones of sedimentation were created which were for example deep ocean basins, shallow marginal seas and barrier zones. In the late Triassic 230 M years ago, the Pangaean con ...
Metamorphic Rocks
... Extreme pressure may also lead to foliation, the flat layers that form in rocks as the rocks are squeezed by pressure ( Figure 1.1). Foliation normally forms when pressure is exerted in only one direction. Metamorphic rocks may also be non-foliated. Quartzite and marble, shown in the concept "Metamo ...
... Extreme pressure may also lead to foliation, the flat layers that form in rocks as the rocks are squeezed by pressure ( Figure 1.1). Foliation normally forms when pressure is exerted in only one direction. Metamorphic rocks may also be non-foliated. Quartzite and marble, shown in the concept "Metamo ...
identifying igneous rocks in the field
... Earth, and owing to their fast cooling rate are relatively fine‐grained and have compositions approximating those of the melts from which they formed. The texture of volcanic rocks can be quite varied and reflects the crystal content of the melt upon eruption and its subsequent coolin ...
... Earth, and owing to their fast cooling rate are relatively fine‐grained and have compositions approximating those of the melts from which they formed. The texture of volcanic rocks can be quite varied and reflects the crystal content of the melt upon eruption and its subsequent coolin ...
Harris Bay
... intrusion of the later Central Series, which contains spectacular ultrabasic breccias, is also demonstrated by this site. The ultrabasic rocks can be shown to have intruded against the Western Granophyre, the contact being an igneous feature and not a fault as previously proposed. This contact is on ...
... intrusion of the later Central Series, which contains spectacular ultrabasic breccias, is also demonstrated by this site. The ultrabasic rocks can be shown to have intruded against the Western Granophyre, the contact being an igneous feature and not a fault as previously proposed. This contact is on ...
GEOLOGY OF THE EARLY MIOCENE ALAÇAMDAĞ (DURSUNBEY
... exposed in an area of about a few tens of km2 in the south of Saðýrlar and southeast of Dursunbey (Figure 6). Intrusions are located in the east of Yaðcýlar and south of Deðirmenciler. They have circular plan views and their diametre is up to 300 metre. Andesitic/dacitic intrusions are massive and l ...
... exposed in an area of about a few tens of km2 in the south of Saðýrlar and southeast of Dursunbey (Figure 6). Intrusions are located in the east of Yaðcýlar and south of Deðirmenciler. They have circular plan views and their diametre is up to 300 metre. Andesitic/dacitic intrusions are massive and l ...
California terranes
... (Şengör and Dewey, 1990, and references therein; Hansen and Dusel-Bacon, 1998; Moores and Day, 1984). 3. Many tectonic models for the western United States have considered only east-dipping subduction zones, and the role of terranes in structural development of an orogen has seldom been considered ...
... (Şengör and Dewey, 1990, and references therein; Hansen and Dusel-Bacon, 1998; Moores and Day, 1984). 3. Many tectonic models for the western United States have considered only east-dipping subduction zones, and the role of terranes in structural development of an orogen has seldom been considered ...
Mineralogy and petrology of rocks from Kamen Volcano, Kamchatka
... volcano, Hb-bearing andesites and decites dominate at Bezimjanniy and medium-high-K subalkaline rocks at Ploskie Sopky volcano. In this report we present geological, petrographical, mineralogical and petrochemical data on the rocks of Kamen volcano. Three consecutive periods of volcano activity were ...
... volcano, Hb-bearing andesites and decites dominate at Bezimjanniy and medium-high-K subalkaline rocks at Ploskie Sopky volcano. In this report we present geological, petrographical, mineralogical and petrochemical data on the rocks of Kamen volcano. Three consecutive periods of volcano activity were ...
Plate Tectonics Wholly, completely
... When two continents meet head-on, neither is subducted because the continental rocks are relatively light and resist downward motion. Instead, the crust tends to ______ and be pushed upward or sideways. After the collision of India into Eurasia, the slow continuous convergence of the two plates over ...
... When two continents meet head-on, neither is subducted because the continental rocks are relatively light and resist downward motion. Instead, the crust tends to ______ and be pushed upward or sideways. After the collision of India into Eurasia, the slow continuous convergence of the two plates over ...
Plate_tectonics_Ss_2014
... When two continents meet head-on, neither is subducted because the continental rocks are relatively light and resist downward motion. Instead, the crust tends to ______ and be pushed upward or sideways. After the collision of India into Eurasia, the slow continuous convergence of the two plates over ...
... When two continents meet head-on, neither is subducted because the continental rocks are relatively light and resist downward motion. Instead, the crust tends to ______ and be pushed upward or sideways. After the collision of India into Eurasia, the slow continuous convergence of the two plates over ...
A Discussion. The Relation of Joint Patterns to the Formation of
... arisen simply through not having had access to current literature. The present note, rather than being contentious in any way, aims principally at providing supplementary information arising from points made by Nilsen. Befare dealing with regional aspects, it is interesting to compare Nilsen's figs. ...
... arisen simply through not having had access to current literature. The present note, rather than being contentious in any way, aims principally at providing supplementary information arising from points made by Nilsen. Befare dealing with regional aspects, it is interesting to compare Nilsen's figs. ...
Rocks
... Help determine past environments Used as time indicators Used for matching rocks from different places ...
... Help determine past environments Used as time indicators Used for matching rocks from different places ...
Summary report on the geological and geophysical characteristics of
... iron deposit, which measures 10 m in width and has a length of about 100 meter, based on aeromagnetic anomalies (Fig. 5). The iron ore is a fine-grained magnetite occurring in a skarn consisting of diopside and tremolite–actinolite with small amounts of garnet and epidote. The epidote occurs also as ...
... iron deposit, which measures 10 m in width and has a length of about 100 meter, based on aeromagnetic anomalies (Fig. 5). The iron ore is a fine-grained magnetite occurring in a skarn consisting of diopside and tremolite–actinolite with small amounts of garnet and epidote. The epidote occurs also as ...
Nazca slab retreat versus compressional deformation in the central
... careful and critical examination of the few localities where folding and faulting is reported during intracordilleran sedimentation, suggests that each example of progressive compressional &formations may correspond to a detailed record of one of the gencralixed compressional events. The deformation ...
... careful and critical examination of the few localities where folding and faulting is reported during intracordilleran sedimentation, suggests that each example of progressive compressional &formations may correspond to a detailed record of one of the gencralixed compressional events. The deformation ...
Chiarenzelli, J., Regan, S., Peck, W., Selleck, B., Cousens, B., Baird, G. and Shrady, C. (2010)
... is sequentially underlain by fine-grained aluminous rocks of the Popple Hill Gneiss (Carl, 1988) and equivalent major paragneiss of Engel and Engel (1953), and then the lower marble. Much of our knowledge of the Adirondack Lowlands stratigraphy comes from exploration related to the sedimentary exhal ...
... is sequentially underlain by fine-grained aluminous rocks of the Popple Hill Gneiss (Carl, 1988) and equivalent major paragneiss of Engel and Engel (1953), and then the lower marble. Much of our knowledge of the Adirondack Lowlands stratigraphy comes from exploration related to the sedimentary exhal ...
Chap 3 marine zones
... Ocean Basin • The deepest part of the ocean floor is called the ocean basin or the abyssal plain • The benthos (bottom-dwelling organisms) that live in the ocean basin are adapted to regions of very low temperatures and very high pressure. ...
... Ocean Basin • The deepest part of the ocean floor is called the ocean basin or the abyssal plain • The benthos (bottom-dwelling organisms) that live in the ocean basin are adapted to regions of very low temperatures and very high pressure. ...
New geologic mapping and SHRIMP U
... U-Pb zircon ages (Fig. 1), these rocks predate the Alisitos Formation by at least 10–15 m.y. These older rocks have been intruded by variably deformed sheets and plutons of Early Cretaceous age (ca. 127–135 Ma), and we suggest that they all formed part of a continental arc on the margin of North Am ...
... U-Pb zircon ages (Fig. 1), these rocks predate the Alisitos Formation by at least 10–15 m.y. These older rocks have been intruded by variably deformed sheets and plutons of Early Cretaceous age (ca. 127–135 Ma), and we suggest that they all formed part of a continental arc on the margin of North Am ...
Chapter 3
... Ocean Basin • The deepest part of the ocean floor is called the ocean basin or the abyssal plain • The benthos (bottom-dwelling organisms) that live in the ocean basin are adapted to regions of very low temperatures and very high pressure. ...
... Ocean Basin • The deepest part of the ocean floor is called the ocean basin or the abyssal plain • The benthos (bottom-dwelling organisms) that live in the ocean basin are adapted to regions of very low temperatures and very high pressure. ...
V: 0
... One piece of evidence that supports the Theory of Plate Tectonics is the discovery of what in both South America and Africa? A. Insects on both continents have similar feeding habits B. The rates of sedimentary rock formation are similar C. The ancient atmosphere in both places are similar D. Fossil ...
... One piece of evidence that supports the Theory of Plate Tectonics is the discovery of what in both South America and Africa? A. Insects on both continents have similar feeding habits B. The rates of sedimentary rock formation are similar C. The ancient atmosphere in both places are similar D. Fossil ...
Variations in MidContinent Rift magma volumes consistent with
... crustal thickening was found in the east arm by Halls [1982]. Seismic reflection data from the GLIMPCE program of active source studies across Lake Superior [Cannon et al., 1989; Shay and Trehu, 1993] show that the crust was initially thinned to about one fourth of its original thickness. The resulti ...
... crustal thickening was found in the east arm by Halls [1982]. Seismic reflection data from the GLIMPCE program of active source studies across Lake Superior [Cannon et al., 1989; Shay and Trehu, 1993] show that the crust was initially thinned to about one fourth of its original thickness. The resulti ...
Metamorphic Rocks
... Regional Metamorphism – both heat and pressure change rock on a grand scale; this usually occurs during major tectonic events such as mountain building ...
... Regional Metamorphism – both heat and pressure change rock on a grand scale; this usually occurs during major tectonic events such as mountain building ...
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.