Calculating the Radiometric Ages of USGS samples
... a tree burned in the violent eruption of Mount Mazama which created Crater Lake. This eruption blanketed several States with ash, providing Y=no/nt = 0.447880803 geologists with an excellent time zone. Charcoal Sample collected from the "Marmes Man" site in southeastern Washington. This rock shelter ...
... a tree burned in the violent eruption of Mount Mazama which created Crater Lake. This eruption blanketed several States with ash, providing Y=no/nt = 0.447880803 geologists with an excellent time zone. Charcoal Sample collected from the "Marmes Man" site in southeastern Washington. This rock shelter ...
Geochronology and thermochronology of Cretaceous
... and white mica stable). Outcrop-scale folds and beddingcleavage intersection lineations are parallel to mapped regional fold axes (Fig. 3a–d). This deformation (D1 ) is the earliest penetrative deformation recorded in the rocks and resulted from shortening in a NE-SW direction. The steep dips of bed ...
... and white mica stable). Outcrop-scale folds and beddingcleavage intersection lineations are parallel to mapped regional fold axes (Fig. 3a–d). This deformation (D1 ) is the earliest penetrative deformation recorded in the rocks and resulted from shortening in a NE-SW direction. The steep dips of bed ...
59 4. DESCRIPTION OF STUDY AREA 4.1. Physiography and
... The geology of project area is dominated by Archaean basement rocks (granite, gneiss and greenstone) which outcrop in an approximately rectangular area bordered (Figure 4.6); • to the south by younger overlying sedimentary strata and the major surface water divide, • to the north by the Soutpansberg ...
... The geology of project area is dominated by Archaean basement rocks (granite, gneiss and greenstone) which outcrop in an approximately rectangular area bordered (Figure 4.6); • to the south by younger overlying sedimentary strata and the major surface water divide, • to the north by the Soutpansberg ...
Geochemistry of volcanic rocks from the Geysers geothermal area
... The Geysers geothermal reservoir in the California Coast Ranges is the world’s largest economically used geothermal system. Surface exposure of volcanic rocks and extensive drill penetration of a N300 km3 subsurface plutonic body (Geysers Plutonic Complex or GPC) that underlies the reservoir allow u ...
... The Geysers geothermal reservoir in the California Coast Ranges is the world’s largest economically used geothermal system. Surface exposure of volcanic rocks and extensive drill penetration of a N300 km3 subsurface plutonic body (Geysers Plutonic Complex or GPC) that underlies the reservoir allow u ...
PDF File - Tulane University
... negative. Apatite, has similar birefringence to quartz, but is uniaxial negative and has a very high relief. In Chalcedony, the fibers are usually elongated perpendicular to the c-crystallographic axis and thus are length fast. Normal quartz, when it show an elongated habit, is elongated parallel to ...
... negative. Apatite, has similar birefringence to quartz, but is uniaxial negative and has a very high relief. In Chalcedony, the fibers are usually elongated perpendicular to the c-crystallographic axis and thus are length fast. Normal quartz, when it show an elongated habit, is elongated parallel to ...
Simonson_2003.pdf
... thermal and mechanical evolution of continental crust as it was affected by changing plate boundary conditions. Contractional structures, such as fold and thrust belts and vertically thickening ductile shear zones, have been observed in regions where collisional tectonics is thought to have increase ...
... thermal and mechanical evolution of continental crust as it was affected by changing plate boundary conditions. Contractional structures, such as fold and thrust belts and vertically thickening ductile shear zones, have been observed in regions where collisional tectonics is thought to have increase ...
Submarine Silicic Volcanism Niyati G. Kalangutkar* and
... Dacites, rhyodacites, calc-alkalic rhyolites, granodiorites and quartz-diorites commonly occur along the various tectonic settings (Table 1). Of these the first three are more abundant as pyroclasts than as lavas. Processes such as differentiation, fractionation, magma mixing and partial melting hav ...
... Dacites, rhyodacites, calc-alkalic rhyolites, granodiorites and quartz-diorites commonly occur along the various tectonic settings (Table 1). Of these the first three are more abundant as pyroclasts than as lavas. Processes such as differentiation, fractionation, magma mixing and partial melting hav ...
Karson, J.A., and Lawrence, R.M., 1997. Tectonic setting of
... Seafloor spreading is accomplished by a combination of mechanical extension and magmatic construction. Along fast-spreading ridges, where nearly continuous axial magma chambers have been identified (Detrick et al., 1987; Toomey et al., 1990), the extrusion of lavas, injection of dikes, and accretion ...
... Seafloor spreading is accomplished by a combination of mechanical extension and magmatic construction. Along fast-spreading ridges, where nearly continuous axial magma chambers have been identified (Detrick et al., 1987; Toomey et al., 1990), the extrusion of lavas, injection of dikes, and accretion ...
The Imbert Formation of northern Hispaniola: a tectono
... mélanges in northern Hispaniola indicates that an intermediate proto-Caribbean oceanic basin was consumed by SWdirected subduction (Draper and Nagle, 1991; Saumur et al., 2010; Escuder-Viruete et al., 2011a, c). The magmatic arcrelated rocks of the Caribbean upper plate have ages that span the Aptia ...
... mélanges in northern Hispaniola indicates that an intermediate proto-Caribbean oceanic basin was consumed by SWdirected subduction (Draper and Nagle, 1991; Saumur et al., 2010; Escuder-Viruete et al., 2011a, c). The magmatic arcrelated rocks of the Caribbean upper plate have ages that span the Aptia ...
Outcomes for new course
... (iii) shale to slate (to phyllite to schist to gneiss) (iv) granite to gneiss - Contrast the two types of metamorphism. Include: (i) ...
... (iii) shale to slate (to phyllite to schist to gneiss) (iv) granite to gneiss - Contrast the two types of metamorphism. Include: (i) ...
Structural Controls on Massive Sulfide Deposition and Hydrothermal
... 300 m southwest of the center of the F Group pit (Copper Mountain, Fig. 2) are severely altered and fractured with abundant shear- and alteration-related tension veins and gashes (Fig. 8A). The attitude of fractures is variable due to the interaction of orthogonal synvolcanic faulting, and the regio ...
... 300 m southwest of the center of the F Group pit (Copper Mountain, Fig. 2) are severely altered and fractured with abundant shear- and alteration-related tension veins and gashes (Fig. 8A). The attitude of fractures is variable due to the interaction of orthogonal synvolcanic faulting, and the regio ...
Do fracture zones define continental margin segmentation
... and profile location is shown in Fig. 2. Several other datasets have been acquired in this region complementing the ACE, which collectively enable a comprehensive evolutionary history of the margin to be determined. Fig. 2 shows the location of the datasets which have been used to define sedimentary a ...
... and profile location is shown in Fig. 2. Several other datasets have been acquired in this region complementing the ACE, which collectively enable a comprehensive evolutionary history of the margin to be determined. Fig. 2 shows the location of the datasets which have been used to define sedimentary a ...
Abstract Volume
... Pin Yan, Yanlin Wang ............................................................................................................................................ 69 Tectonic History of South Delhi Fold Belt, A Resemblance with South Granulite Terrane and East African Orogen. Sundaralingam K., Tanush ...
... Pin Yan, Yanlin Wang ............................................................................................................................................ 69 Tectonic History of South Delhi Fold Belt, A Resemblance with South Granulite Terrane and East African Orogen. Sundaralingam K., Tanush ...
EASTERN RIFT STRUCTURAL GEOLOGY – TECTONICS
... exploiting the weak collisional zone at the contact between the Archean Tanzania craton and Proterozoic orogenic belts (Smith and Mosley, 1993). The Eastern branch of EARS developed in Neoproterozoic orogenic belts (referred to as East African Oregon) whereas the western rift developed in Paleo and ...
... exploiting the weak collisional zone at the contact between the Archean Tanzania craton and Proterozoic orogenic belts (Smith and Mosley, 1993). The Eastern branch of EARS developed in Neoproterozoic orogenic belts (referred to as East African Oregon) whereas the western rift developed in Paleo and ...
Could Iceland be a modern analogue for the Earth`s early
... indicating that tholeiitic basalt is the most suitable source for the latter. Consequently, it has been proposed that, in Iceland, depending on their location relative to the ridge-axis and the centre of the plume, felsic magmas could be generated either by fractional crystallization or by partial m ...
... indicating that tholeiitic basalt is the most suitable source for the latter. Consequently, it has been proposed that, in Iceland, depending on their location relative to the ridge-axis and the centre of the plume, felsic magmas could be generated either by fractional crystallization or by partial m ...
Sedimentary Rocks
... As clasts are rolled around during transportation, sharp corners tend to be knocked off, and the clasts become more rounded the farther they are transported. Angular grains are usually found only near the source rock. ...
... As clasts are rolled around during transportation, sharp corners tend to be knocked off, and the clasts become more rounded the farther they are transported. Angular grains are usually found only near the source rock. ...
The birth of the Rheic Ocean — Early Palaeozoic subsidence
... non-fixist approach, in which terranes are always moving in and out of such cross-sections. The basic principle here is that the present-day juxtaposition of terranes does not represent, in most cases, the original relationships of the terranes. The relative motion of many Variscan terranes is measur ...
... non-fixist approach, in which terranes are always moving in and out of such cross-sections. The basic principle here is that the present-day juxtaposition of terranes does not represent, in most cases, the original relationships of the terranes. The relative motion of many Variscan terranes is measur ...
visualization 3: earthquakes at divergent plate
... Let’s look at earthquakes at a different type of plate boundary. Notice here that there are clusters of earthquakes extending north-south through eastern Africa. Why are there earthquakes in this region? ‘Quakes Question #4: How are the earthquakes in the East African Rift Zone similar and different ...
... Let’s look at earthquakes at a different type of plate boundary. Notice here that there are clusters of earthquakes extending north-south through eastern Africa. Why are there earthquakes in this region? ‘Quakes Question #4: How are the earthquakes in the East African Rift Zone similar and different ...
Imaging igneous rocks on the North Atlantic rifted continental margin
... together with direct imaging of the extrusive basalts enables us to constrain the volumes of extrusive and intrusive igneous rocks produced near the Faroe Islands to be 340–420 and 560–780 km3 per kilometre along strike, respectively. The COT marked both by high-velocity intrusions and lower-crustal ...
... together with direct imaging of the extrusive basalts enables us to constrain the volumes of extrusive and intrusive igneous rocks produced near the Faroe Islands to be 340–420 and 560–780 km3 per kilometre along strike, respectively. The COT marked both by high-velocity intrusions and lower-crustal ...
imp prefaz.qxp - Istituto Nazionale di Oceanografia e di Geofisica
... - Section 5b, (Fig. 4d), southern Bavaria-eastern Alps- Trieste, again shows a modification of the deep structure, especially at its south-eastern half. The edge of the Adria Moho is less sharp than in the former transects and appears to be bent north-eastwards; the wedge extension is smaller than i ...
... - Section 5b, (Fig. 4d), southern Bavaria-eastern Alps- Trieste, again shows a modification of the deep structure, especially at its south-eastern half. The edge of the Adria Moho is less sharp than in the former transects and appears to be bent north-eastwards; the wedge extension is smaller than i ...
Dumitru FRUNZESCU
... organic matter content and the chemical composition classify them within the category of hydrocarbon source rocks. The laboratory analyses performed on the organic matter taken out from these formations made it possible to remark on the type of initial organic matter, transformation degree and its a ...
... organic matter content and the chemical composition classify them within the category of hydrocarbon source rocks. The laboratory analyses performed on the organic matter taken out from these formations made it possible to remark on the type of initial organic matter, transformation degree and its a ...
Chapter 1 Reading rock exposures: how rock exposures contain
... but when atoms combine together they form molecules. Molecules of different chemical elements combined together are called compounds. An example of a mineral formed of one chemical element is diamond, which is made entirely of the element carbon (designated: C). Diamond (Figure 1.4) is of course a r ...
... but when atoms combine together they form molecules. Molecules of different chemical elements combined together are called compounds. An example of a mineral formed of one chemical element is diamond, which is made entirely of the element carbon (designated: C). Diamond (Figure 1.4) is of course a r ...
Chapter 1 Reading rock exposures: how rock exposures contain
... When rock becomes very hot, more than 600◦ C, the minerals begin to melt and nearly all minerals have melted by a temperature of 1800◦ C. As the minerals melt, the atoms and molecules they contain are released to form a ‘bath’ of liquid called magma. This liquid mixture of atoms and molecules is usu ...
... When rock becomes very hot, more than 600◦ C, the minerals begin to melt and nearly all minerals have melted by a temperature of 1800◦ C. As the minerals melt, the atoms and molecules they contain are released to form a ‘bath’ of liquid called magma. This liquid mixture of atoms and molecules is usu ...
Orogenic Belts and Orogenic Sediment Provenance
... archetypal example being the Northern Oman orogen assembled at Late Cretaceous times (Searle and Stevens 1984). The pro side of the obduction orogen is a thick-skinned thrust belt, beneath which continental blueschists and eclogites of the axial belt may be exposed. Its tectonic lid consists of a co ...
... archetypal example being the Northern Oman orogen assembled at Late Cretaceous times (Searle and Stevens 1984). The pro side of the obduction orogen is a thick-skinned thrust belt, beneath which continental blueschists and eclogites of the axial belt may be exposed. Its tectonic lid consists of a co ...
CHAPTER 4 GEOCHRONOLOGY AND ISOTOPIC CHARACTER OF
... stratigraphic column; the terms “late” and “early” are used in reference to age or time. Thus, Upper Cretaceous rocks statigraphically overlie Lower Cretaceous rocks, but were deposited during the Late Cretaceous following deposition of the older rocks during the Early Cretaceous. It is also importa ...
... stratigraphic column; the terms “late” and “early” are used in reference to age or time. Thus, Upper Cretaceous rocks statigraphically overlie Lower Cretaceous rocks, but were deposited during the Late Cretaceous following deposition of the older rocks during the Early Cretaceous. It is also importa ...
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.