Rock Types and Stratigraphy
... occurrence. In the former type, the magma crystallizes within the Earth’s crust, whereas in the latter, it solidifies at the surface, having erupted as lavas and/or pyroclasts from a volcano. The intrusions have been exposed at the surface by erosion. They have been further subdivided on the basis o ...
... occurrence. In the former type, the magma crystallizes within the Earth’s crust, whereas in the latter, it solidifies at the surface, having erupted as lavas and/or pyroclasts from a volcano. The intrusions have been exposed at the surface by erosion. They have been further subdivided on the basis o ...
as a PDF
... Chemical analyses of these rocks have not yet been carried out. RHYOLITIC AND DACITIC DIKES These rocks are commonly found in the entire study area. They can be differentiated into two groups based on structural control. The first group, with a strike N 75-90° E, is present in the Estancia La Seña a ...
... Chemical analyses of these rocks have not yet been carried out. RHYOLITIC AND DACITIC DIKES These rocks are commonly found in the entire study area. They can be differentiated into two groups based on structural control. The first group, with a strike N 75-90° E, is present in the Estancia La Seña a ...
4- Igneous Rock (Intrusive)
... Furthermore, the upper part of the oceanic crust is composed almost entirely of basalt. Gabbro is much less common than basalt, at least in the continental crust or where it can be easily observed. Small intrusive bodies of gabbro do occur in the continental crust, but intermediate to felsic intrusi ...
... Furthermore, the upper part of the oceanic crust is composed almost entirely of basalt. Gabbro is much less common than basalt, at least in the continental crust or where it can be easily observed. Small intrusive bodies of gabbro do occur in the continental crust, but intermediate to felsic intrusi ...
MINERALOGICAL MAGAZINE Petrogenetic processes associated
... representing the intermediate or low crust. After intrusion into the upper crust, the major and traceelement concentrations of the silicic magmas were modified through fractional crystallization dominated by removal of alkali feldspar, and transport of elements with a fluid phase. The silicic magmas ...
... representing the intermediate or low crust. After intrusion into the upper crust, the major and traceelement concentrations of the silicic magmas were modified through fractional crystallization dominated by removal of alkali feldspar, and transport of elements with a fluid phase. The silicic magmas ...
Geologic History of Arizona - Jan C. Rasmussen, Ph.D., Registered
... the sea floor, in an environment similar to the ‘black smokers’ observed on the deep seafloor today. ...
... the sea floor, in an environment similar to the ‘black smokers’ observed on the deep seafloor today. ...
Minimum Age of Initiation of Collision between India and Asia North
... Formation is about 450 m thick. The base of the unit is dated as upper Danian, while the top is dated as early Lutetian (Willems and Zhang 1993b; Willems et al. 1996). The highest known sediments preserved in this region are coastal to lagoonal (Willems 1993; Willems et al. 1996), greenish-gray marl ...
... Formation is about 450 m thick. The base of the unit is dated as upper Danian, while the top is dated as early Lutetian (Willems and Zhang 1993b; Willems et al. 1996). The highest known sediments preserved in this region are coastal to lagoonal (Willems 1993; Willems et al. 1996), greenish-gray marl ...
Canada`s craton: A bottoms-up view
... recognized within the cratons of continents today (Bleeker, 2003). The largest mass of lithosphere beneath these cratons underlies the Moho in the mantle. Thus, the long-term strength and stability of a craton must be engendered in the properties of its mantle lithosphere, which may ultimately be ti ...
... recognized within the cratons of continents today (Bleeker, 2003). The largest mass of lithosphere beneath these cratons underlies the Moho in the mantle. Thus, the long-term strength and stability of a craton must be engendered in the properties of its mantle lithosphere, which may ultimately be ti ...
EOCENE TECTONIC EVOLUTION OF NW MEXICO (SONORA and
... and Sonora, that is, actually, between two parts of the Baja-Borderland terrane, or block.] Gastil (1991) assumed that the terrane (block) in question could have travelled north along a California-Oaxaca megashear.with a convexity towards the West (implying, possibly, an accordance with the subducti ...
... and Sonora, that is, actually, between two parts of the Baja-Borderland terrane, or block.] Gastil (1991) assumed that the terrane (block) in question could have travelled north along a California-Oaxaca megashear.with a convexity towards the West (implying, possibly, an accordance with the subducti ...
Petrological nature of the oceanic Moho
... The gabbro/peridotite (dunite) boundaries can be classified into two types, gabbor-in-dunite and dunite-in-gabbro, in the northern Oman ophiolite. In the former type, gabbros appear as intrusive bands or sills in dunite (or wehrlite) around the transition zone, and the transition is relatively gradu ...
... The gabbro/peridotite (dunite) boundaries can be classified into two types, gabbor-in-dunite and dunite-in-gabbro, in the northern Oman ophiolite. In the former type, gabbros appear as intrusive bands or sills in dunite (or wehrlite) around the transition zone, and the transition is relatively gradu ...
No Slide Title
... • Large T contrast reflected in smaller “grain size” within igneous rock near contact = “ Chilled Margin”. • Concordance or Discordance – Required to differentiate between Sills & Dykes. ...
... • Large T contrast reflected in smaller “grain size” within igneous rock near contact = “ Chilled Margin”. • Concordance or Discordance – Required to differentiate between Sills & Dykes. ...
Seismic reflection image of the Great Sumatra
... As reported for the Middle America trench15, plate bending at subduction zones generates trench-parallel conjugate normal faults that dissect the entire sedimentary column and penetrate into the basement, producing seafloor and basement offsets of 100-500 m. On profiles collected 65-175 km south of ...
... As reported for the Middle America trench15, plate bending at subduction zones generates trench-parallel conjugate normal faults that dissect the entire sedimentary column and penetrate into the basement, producing seafloor and basement offsets of 100-500 m. On profiles collected 65-175 km south of ...
Chapter 2: Non-tectonic Structures
... These rocks flow more readily than any other common rock type and can form folded structures under surface temperature and pressure These structures that move upward and gravitationally intrude overlying sediments are called diapirs. ...
... These rocks flow more readily than any other common rock type and can form folded structures under surface temperature and pressure These structures that move upward and gravitationally intrude overlying sediments are called diapirs. ...
Mantle Influence, Rifting and Magmatism in the East African Rift
... the late Tertiary to form the southern part of the present Western rift and the southern EARS branches. An important outcome of the deep mantle tumescence and consequent crust fracturing during the pre-EARS period had been the creation of the world's largest igneous activity since the Mesozoic. Cons ...
... the late Tertiary to form the southern part of the present Western rift and the southern EARS branches. An important outcome of the deep mantle tumescence and consequent crust fracturing during the pre-EARS period had been the creation of the world's largest igneous activity since the Mesozoic. Cons ...
The East African Rift System: Does It Have Oil and Gas Potential?
... of meters and continued to swell, expanding eastwards, creating cracks that opened up along weak fault lines (Klemes et al., 2010). This is theory is complimented by studies conducted by Davis and Slack (2002) where in comparison of S-wave delays and P-wave tomography, they characterized the rising ...
... of meters and continued to swell, expanding eastwards, creating cracks that opened up along weak fault lines (Klemes et al., 2010). This is theory is complimented by studies conducted by Davis and Slack (2002) where in comparison of S-wave delays and P-wave tomography, they characterized the rising ...
article in press - Centro de Geociencias
... Paleozoic rocks in southern Mexico occur in two terranes, Oaxaquia (Oaxacan Complex) and Mixteca (Acatlán Complex) that appear to record: (1) Ordovician rifting on the southern margin of the Rheic Ocean, (2) passive drifting with Amazonia during the Silurian, (3) DevonianPermian subduction beneath s ...
... Paleozoic rocks in southern Mexico occur in two terranes, Oaxaquia (Oaxacan Complex) and Mixteca (Acatlán Complex) that appear to record: (1) Ordovician rifting on the southern margin of the Rheic Ocean, (2) passive drifting with Amazonia during the Silurian, (3) DevonianPermian subduction beneath s ...
California Rocks and Minerals - Rediscovering the Golden State
... Mountains east of the Imperial Valley. They formed when a variety of rocks from a deep ocean basin or trench were thrust together during the late Mesozoic Era. The related Garlock and Rand schists may have been broken off and dragged away from the other side of strike-slip faults to their present lo ...
... Mountains east of the Imperial Valley. They formed when a variety of rocks from a deep ocean basin or trench were thrust together during the late Mesozoic Era. The related Garlock and Rand schists may have been broken off and dragged away from the other side of strike-slip faults to their present lo ...
Metamorphic Facies
... NOTE: Hot inter-granular fluids (commonly H2O & CO2 ) speed up metamorphic reactions and fluids are heated by geothermal gradient or igneous intrusion. ...
... NOTE: Hot inter-granular fluids (commonly H2O & CO2 ) speed up metamorphic reactions and fluids are heated by geothermal gradient or igneous intrusion. ...
Slavonian excursion
... deposits in Poljanska (Mt. Papuk) are interstratified with Ottnangian - Karpatian and Badenian (Helvetian, i.e. Miocene) saline sediments. They are developed in two horizons and have a hybrid composition, due to the mixture of carbonate sediments (dolomite), pyroclastic and volcanoclastic material a ...
... deposits in Poljanska (Mt. Papuk) are interstratified with Ottnangian - Karpatian and Badenian (Helvetian, i.e. Miocene) saline sediments. They are developed in two horizons and have a hybrid composition, due to the mixture of carbonate sediments (dolomite), pyroclastic and volcanoclastic material a ...
Stratigraphy, geochemistry and tectonic significance of the
... dominated by composite batholiths commonly cut by silicic and mafic dike swarms. More discontinuous outcrops of lava flows, pyroclastic deposits and hypabyssal intrusions make up the inland volcanic sequences. Between approximately 100°W and western Oaxaca, the magmatism tends to be Oligocene in age ...
... dominated by composite batholiths commonly cut by silicic and mafic dike swarms. More discontinuous outcrops of lava flows, pyroclastic deposits and hypabyssal intrusions make up the inland volcanic sequences. Between approximately 100°W and western Oaxaca, the magmatism tends to be Oligocene in age ...
Rheological heterogeneity, mechanical anisotropy
... the tectonic behaviour of the lithosphere. Lateral rheological heterogeneity of the continental lithosphere may result from various sources, with variations in geothermal gradient being the principal one. The oldest domains of continents, the cratonic nuclei, are characterized by a relatively cold, ...
... the tectonic behaviour of the lithosphere. Lateral rheological heterogeneity of the continental lithosphere may result from various sources, with variations in geothermal gradient being the principal one. The oldest domains of continents, the cratonic nuclei, are characterized by a relatively cold, ...
Synthesis of Results From the CD-ROM Experiment
... The most plausible explanation for the north-dipping, high velocity, mantle anomaly is that it is an ancient slab fragment, for example a remnant of the rifted margin of the Wyoming Province (Tyson et al., 2002) or a collapsed back-arc basin (Yuan and Dueker, this volume; Zurek and Dueker, this volu ...
... The most plausible explanation for the north-dipping, high velocity, mantle anomaly is that it is an ancient slab fragment, for example a remnant of the rifted margin of the Wyoming Province (Tyson et al., 2002) or a collapsed back-arc basin (Yuan and Dueker, this volume; Zurek and Dueker, this volu ...
Flood basalts, continental breakup and the dispersal of
... episode at 75–70 Ma is not considered as volcanic age emplacement, and the last volcanic event was between 68 and 49 Ma. The magmatism in the Benue Trough is partly contemporaneous with that of NE Brazil along the Potiguar rift and in the Maranhão basin (∼129–124 Ma; Baksi and Archibald, 1997). The ...
... episode at 75–70 Ma is not considered as volcanic age emplacement, and the last volcanic event was between 68 and 49 Ma. The magmatism in the Benue Trough is partly contemporaneous with that of NE Brazil along the Potiguar rift and in the Maranhão basin (∼129–124 Ma; Baksi and Archibald, 1997). The ...
Caribbean Geological Conference 18th
... generally similar to that of mid-oceanic ridge basalts (Fig. 5). However, this basalt chemistry differs in detail from N-type MORB in showing a distinctive arc-like depletion in HFSE, particularly in Nb and Ta and some enrichment in LILE. These are the features of the basalts of the Lau Basin in the ...
... generally similar to that of mid-oceanic ridge basalts (Fig. 5). However, this basalt chemistry differs in detail from N-type MORB in showing a distinctive arc-like depletion in HFSE, particularly in Nb and Ta and some enrichment in LILE. These are the features of the basalts of the Lau Basin in the ...
3.8 Rocks and Processes of the Rock Cycle
... The rock beneath the Earth’s surface is sometimes heated to high enough temperatures that it melts to create magma. Different magmas have different composition and contain whatever elements were in the rock or rocks that melted. Magmas also contain gases. The main elements are the same as the elemen ...
... The rock beneath the Earth’s surface is sometimes heated to high enough temperatures that it melts to create magma. Different magmas have different composition and contain whatever elements were in the rock or rocks that melted. Magmas also contain gases. The main elements are the same as the elemen ...
Chapter 2: Rocks of the Southeastern US
... The Blue Ridge and Piedmont are distinct physiographic areas, but they share similar types of crystalline igneous and metamorphic rocks. This region was at the center of several orogenic events that occurred throughout the Precambrian and Paleozoic, and many of the rocks found here were metamorphose ...
... The Blue Ridge and Piedmont are distinct physiographic areas, but they share similar types of crystalline igneous and metamorphic rocks. This region was at the center of several orogenic events that occurred throughout the Precambrian and Paleozoic, and many of the rocks found here were metamorphose ...
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.