Imaging igneous rocks on the North Atlantic rifted continental margin
... directly observed, that these fault blocks extend under the basalt onto the northern slope of the Faroe-Shetland Basin. The velocities of the underlying sediment layer determined by Richardson et al. (1999) were, however, not well constrained due to a trade-off between velocity and thickness during ...
... directly observed, that these fault blocks extend under the basalt onto the northern slope of the Faroe-Shetland Basin. The velocities of the underlying sediment layer determined by Richardson et al. (1999) were, however, not well constrained due to a trade-off between velocity and thickness during ...
Catastrophic Granite Formation Rapid Melting of
... The timescale for the generation of granitic magmas and their subsequent intrusion, crystallization, and cooling as plutons is no longer incompatible with the biblical time frames of the global, year-long Flood cataclysm and of 6,000–7,000 years for earth history. Though partial melting in the lower ...
... The timescale for the generation of granitic magmas and their subsequent intrusion, crystallization, and cooling as plutons is no longer incompatible with the biblical time frames of the global, year-long Flood cataclysm and of 6,000–7,000 years for earth history. Though partial melting in the lower ...
QUARTZ XENOCRYSTS IN OLIVINE BASALT FROM THE
... The secondhypothesis is extremely unlikely in view of the relations of the minerals actually present in the rock. The temperatures existent during the reaction period are suggested(1) by the presenceof sanidine, (2) lack of intensive alteration of the xenoliths, and (3) the absenceof tridymite inver ...
... The secondhypothesis is extremely unlikely in view of the relations of the minerals actually present in the rock. The temperatures existent during the reaction period are suggested(1) by the presenceof sanidine, (2) lack of intensive alteration of the xenoliths, and (3) the absenceof tridymite inver ...
09_chapter 1
... engulfed about 1/3rd of the land area at the end of cretaceous era. The so called catastrophic event was manifested in the form of outpouring of enormous volume of Basaltic lava that covered hundreds of square km. of the land through spasmodic eruptions which gave rise to piles of lava flows. These ...
... engulfed about 1/3rd of the land area at the end of cretaceous era. The so called catastrophic event was manifested in the form of outpouring of enormous volume of Basaltic lava that covered hundreds of square km. of the land through spasmodic eruptions which gave rise to piles of lava flows. These ...
- ResearchOnline@JCU
... volcanic sequences form an aerially-extensive volcanic succession which is predominantly basaltic to andesitic and ranges in age from 54.8 to 35.4 Ma (Atherton et al., 1985; Noble et al., 1990; Section A). Oligocene mafic dykes also crop out throughout the region and have been recently dated at 29.4 ...
... volcanic sequences form an aerially-extensive volcanic succession which is predominantly basaltic to andesitic and ranges in age from 54.8 to 35.4 Ma (Atherton et al., 1985; Noble et al., 1990; Section A). Oligocene mafic dykes also crop out throughout the region and have been recently dated at 29.4 ...
Origin and Evolution of the Western Snake River Plain
... deltaic sediments of Lake Idaho. These basalts are associated with young faults that reflect Basin and Range extension. We propose that the western SRP graben represents an aulocogenlike structure formed in response to thermal tumescence above the Yellowstone plume head as it rose under eastern Oreg ...
... deltaic sediments of Lake Idaho. These basalts are associated with young faults that reflect Basin and Range extension. We propose that the western SRP graben represents an aulocogenlike structure formed in response to thermal tumescence above the Yellowstone plume head as it rose under eastern Oreg ...
Seismic imaging of a hot upwelling beneath the British Isles
... and Paleogene magmatism are all indicative of an upwelling in the upper mantle. Furthermore, such an upwelling may be the cause of the majority of British earthquakes, many of which have poorly understood origins. Available earthquake focal mechanisms suggest that the earthquakes are caused by tensi ...
... and Paleogene magmatism are all indicative of an upwelling in the upper mantle. Furthermore, such an upwelling may be the cause of the majority of British earthquakes, many of which have poorly understood origins. Available earthquake focal mechanisms suggest that the earthquakes are caused by tensi ...
flow-layering in alpine peridotite-gabbro
... millimeter to 10 ern in pegmatitic layers (Fig. 3). The textures of the pegmatitic layers in outcrop resemble the textures of fine-grained layers in thin section. Foliation and lineation characterize flow-layers (Figs. 2, 3). Foliation, shown by planar orientation of individual grains or clusters of ...
... millimeter to 10 ern in pegmatitic layers (Fig. 3). The textures of the pegmatitic layers in outcrop resemble the textures of fine-grained layers in thin section. Foliation and lineation characterize flow-layers (Figs. 2, 3). Foliation, shown by planar orientation of individual grains or clusters of ...
Continental geotherm and the evolution of rifted margins
... et al., 2003). Lowering the Tp of the sublithospheric mantle to below 1300 8C similarly leads to a decrease in the amount of melt generated at effectively infinite stretching factors (Fig. 2). For a base lithospheric Tp of 1200 8C, ,2 km of basalt is predicted, even for very rapid stretching (Minshu ...
... et al., 2003). Lowering the Tp of the sublithospheric mantle to below 1300 8C similarly leads to a decrease in the amount of melt generated at effectively infinite stretching factors (Fig. 2). For a base lithospheric Tp of 1200 8C, ,2 km of basalt is predicted, even for very rapid stretching (Minshu ...
Paleogene–early Miocene igneous rocks and geodynamics of the
... that may account for the igneous rocks and orthopyroxene-rich mantle rocks. However, results of seismic tomography on subducted slabs beneath the studied area combined with geological data demonstrate that igneous rocks and mantle rocks cannot be explained by the same subduction process. We propose ...
... that may account for the igneous rocks and orthopyroxene-rich mantle rocks. However, results of seismic tomography on subducted slabs beneath the studied area combined with geological data demonstrate that igneous rocks and mantle rocks cannot be explained by the same subduction process. We propose ...
The Mings Bight Ophiolite Complex, Newfoundland: Appalachian
... The Mings Bight Ophiolite Complex, of probable early Ordovician age, is disposed in four major thrust sheets with an eastward vergence at the northern end of the Baie Verte Lineament. This narrow ophiolitic belt, and (to the south) an adjacent zone of early Devonian volcanic rocks and sediments, wer ...
... The Mings Bight Ophiolite Complex, of probable early Ordovician age, is disposed in four major thrust sheets with an eastward vergence at the northern end of the Baie Verte Lineament. This narrow ophiolitic belt, and (to the south) an adjacent zone of early Devonian volcanic rocks and sediments, wer ...
Petrogenesis of felsic igneous rocks associated with the
... and geochemistry of the Sirniö Group, while the co-authors handled lithostratigraphy. In III, L. S. Lauri’s contribution included field geology, whole-rock geochemistry, a part of the Nd isotope analyses, and petrological modeling. 1. Introduction Continental extension is often characterized by an a ...
... and geochemistry of the Sirniö Group, while the co-authors handled lithostratigraphy. In III, L. S. Lauri’s contribution included field geology, whole-rock geochemistry, a part of the Nd isotope analyses, and petrological modeling. 1. Introduction Continental extension is often characterized by an a ...
A long in situ section of the lower ocean crust: results of ODP Leg
... the transform due to a spreading direction change [6]. The top of Atlantis Bank, where the hole is located, is a wave-cut platform exposing gabbro, with less than 100 m total relief over a 25 km2 area [7]. Seismic Moho is estimated to be approximately 5.3 km below Hole 735B [8] and is interpreted as ...
... the transform due to a spreading direction change [6]. The top of Atlantis Bank, where the hole is located, is a wave-cut platform exposing gabbro, with less than 100 m total relief over a 25 km2 area [7]. Seismic Moho is estimated to be approximately 5.3 km below Hole 735B [8] and is interpreted as ...
Geochemistry of mafic rocks and melt inclusions and their
... chambers for their relatively low mantle temperature (Niu and O’hara, 2008), and consequently have a low degree of mantle partial melting. Instead, several small-scale magma intrusions commonly occurred within the crust (Mccaig and Harris, 2012). The lack of a steady-state magma chamber makes it dif ...
... chambers for their relatively low mantle temperature (Niu and O’hara, 2008), and consequently have a low degree of mantle partial melting. Instead, several small-scale magma intrusions commonly occurred within the crust (Mccaig and Harris, 2012). The lack of a steady-state magma chamber makes it dif ...
On origin of near-axis volcanism and faulting at fast spreading mid
... by steep slopes that are interpreted as inwardand outward-dipping normal faults [1,17]. Inward-dipping normal faults are ubiquitous on slow spreading mid-ocean ridges, where they accommodate up to 10^20% of extension associated with plate spreading [18,19]. Outward-dipping normal faults are, however ...
... by steep slopes that are interpreted as inwardand outward-dipping normal faults [1,17]. Inward-dipping normal faults are ubiquitous on slow spreading mid-ocean ridges, where they accommodate up to 10^20% of extension associated with plate spreading [18,19]. Outward-dipping normal faults are, however ...
Igneous Rocks and Intrusive Igneous Activity
... a Most magma originates within Earth’s upper mantle or lower crust at or near divergent and convergent plate boundaries. a Several processes bring about chemical changes in magma, so magma may evolve from one kind into another. a All igneous rocks form when magma or lava cools and crystallizes or by ...
... a Most magma originates within Earth’s upper mantle or lower crust at or near divergent and convergent plate boundaries. a Several processes bring about chemical changes in magma, so magma may evolve from one kind into another. a All igneous rocks form when magma or lava cools and crystallizes or by ...
Geologic Map of the Melba Quadrangle,Canyon and Ada Counties
... The oldest group of lava flows and eruptive points in the Melba quadrangle are composed of iron- and titanium-enriched basalt that is impoverished in silica. These flows can best be described as ferrobasalts and are part of the basalt group in the western Snake River Plain that White and others (200 ...
... The oldest group of lava flows and eruptive points in the Melba quadrangle are composed of iron- and titanium-enriched basalt that is impoverished in silica. These flows can best be described as ferrobasalts and are part of the basalt group in the western Snake River Plain that White and others (200 ...
Petrological models of magma evolution and deep crustal structure
... high MgO content (15-18 wt%). Although picrites occur in provinces affected by plume magmatism, the largest volumes of volcanic rocks are tholeiitic basalts, with a fairly constant MgO concentration (6-8 wt%). The discrepancy between the predicted composition of the primary melt at depth and the obs ...
... high MgO content (15-18 wt%). Although picrites occur in provinces affected by plume magmatism, the largest volumes of volcanic rocks are tholeiitic basalts, with a fairly constant MgO concentration (6-8 wt%). The discrepancy between the predicted composition of the primary melt at depth and the obs ...
as a PDF
... Extensive outcrops of plutonic and volcanic rocks are found in the northwest part of Patagonia, Argentina. In the La Esperanza area, Llambías and Rapela (1984) and Rapela and Llambías (1985) recognized the existence of an event related to the Gondwanan Magmatic cycle. According to these authors, two ...
... Extensive outcrops of plutonic and volcanic rocks are found in the northwest part of Patagonia, Argentina. In the La Esperanza area, Llambías and Rapela (1984) and Rapela and Llambías (1985) recognized the existence of an event related to the Gondwanan Magmatic cycle. According to these authors, two ...
Magmas and Lavas
... depths and has the ability to migrate to shallower levels where it either crystallizes at depth giving rise to igneous intrusions, or erupts at the surface to form volcanic rocks. Lava: Is erupted molten material that can flow on the surface of the earth. A lava may therefore be considered a magma t ...
... depths and has the ability to migrate to shallower levels where it either crystallizes at depth giving rise to igneous intrusions, or erupts at the surface to form volcanic rocks. Lava: Is erupted molten material that can flow on the surface of the earth. A lava may therefore be considered a magma t ...
North America`s Midcontinent Rift: When Rift Met LIP
... Previous conventional wisdom The MCR’s “failure” - ending of volcanism and extension and thus its failure to develop into a new ocean basin has been attributed to later compression & reverse faulting (basin inversion) during the Grenville orogeny ...
... Previous conventional wisdom The MCR’s “failure” - ending of volcanism and extension and thus its failure to develop into a new ocean basin has been attributed to later compression & reverse faulting (basin inversion) during the Grenville orogeny ...
Mackenzie Large Igneous Province
The Mackenzie Large Igneous Province (MLIP) is a major Mesoproterozoic large igneous province of the southwestern, western and northwestern Canadian Shield in Canada. It consists of a group of related igneous rocks that were formed during a massive igneous event starting about 1,270 million years ago. The large igneous province extends from the Arctic in Nunavut to near the Great Lakes in Northwestern Ontario where it meets with the smaller Matachewan dike swarm. Included in the Mackenzie Large Igneous Province are the large Muskox layered intrusion, the Coppermine River flood basalt sequence and the massive northwesterly trending Mackenzie dike swarm.As a large igneous province, it is an extremely large area of related igneous rocks that were emplaced over an extremely short geological time span. The igneous rocks comprising the Mackenzie Large Igneous Province originated from processes not associated with normal plate tectonics and seafloor spreading. It is one of the several large igneous provinces scattered throughout the Canadian landscape, which can be thousands of kilometres in volume and area. The Mackenzie Large Igneous Province is also one of the largest Proterozoic magmatic provinces on Earth, as well as the world's largest and best-preserved continental flood basalt terrain. Igneous rocks of the Mackenzie Large Igneous Province are generally mafic in composition, including basalt and gabbro.Even though the Mackenzie Large Igneous Province is classified as a large igneous province like other extremely large accumulations of igneous rocks on Earth, it is much larger than large igneous province standards. The standard size classification for large igneous provinces is a minimum areal extent of 100,000 km2 (39,000 sq mi). However, the Mackenzie dike swarm itself occupies an area of at least 2,700,000 km2 (1,000,000 sq mi), making the Mackenzie Large Igneous Province larger than the Ontong Java Plateau in the southwestern Pacific Ocean and the U.S. state of Alaska.