1 MELT VISCOSITY, TEMPERATURE AND TRANSPORT
... 4. Viscosity of the CY-1/1A lavas Melt viscosities were calculated for reported rock compositions from the CY1/1A drill holes, using the method of Shaw [23] (Fig. 5). We did not use more complex formulations which include the effects of crystallinity (e.g., [24]) because the crystal content during v ...
... 4. Viscosity of the CY-1/1A lavas Melt viscosities were calculated for reported rock compositions from the CY1/1A drill holes, using the method of Shaw [23] (Fig. 5). We did not use more complex formulations which include the effects of crystallinity (e.g., [24]) because the crystal content during v ...
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... Abstract: Payún Matru Volcanic Field is a Quaternary monogenetic volcanic field that hosts scoria cones with perfect to breached morphologies. Los Morados complex is a group of at least four closely spaced scoria cones (Los Morados main cone and the older Cones A, B, and C). Los Morados main cone wa ...
... Abstract: Payún Matru Volcanic Field is a Quaternary monogenetic volcanic field that hosts scoria cones with perfect to breached morphologies. Los Morados complex is a group of at least four closely spaced scoria cones (Los Morados main cone and the older Cones A, B, and C). Los Morados main cone wa ...
High-Sr Volcanic Domes from the Lassen
... from University of Washington, for your incredible patience and assistance you provided in the Isotope Geochemistry Lab. To my field assistant Janet Stout: thank you for hauling rocks and battling bears with me. To my father, David Stout, for financial support without I would not have been able t ...
... from University of Washington, for your incredible patience and assistance you provided in the Isotope Geochemistry Lab. To my field assistant Janet Stout: thank you for hauling rocks and battling bears with me. To my father, David Stout, for financial support without I would not have been able t ...
Cedar Butte and Cogenetic Quaternary Rhyolite Domes of the
... Butte. Spear (1979) also notes disequilibrium phenocryst assemblages and textures in similar enclaves elsewhere in the dome. He interpreted the enclaves as hybrid inclusions produced by mixing of partially crystallized mafic magma with the host rhyolite. However, most of the enclaves vary from ang ...
... Butte. Spear (1979) also notes disequilibrium phenocryst assemblages and textures in similar enclaves elsewhere in the dome. He interpreted the enclaves as hybrid inclusions produced by mixing of partially crystallized mafic magma with the host rhyolite. However, most of the enclaves vary from ang ...
Rift-Related Transition from Andesite to Rhyolite
... The tectonic regime of New Zealand’s North Island is strongly linked to and influenced by the oblique (208) convergence of the Pacific and Australian plates at c. 42 mm a1 (Fig. 1; DeMets et al., 1994) along a NE^ SW-trending subduction interface. The eastern part of the North Island (the forearc ...
... The tectonic regime of New Zealand’s North Island is strongly linked to and influenced by the oblique (208) convergence of the Pacific and Australian plates at c. 42 mm a1 (Fig. 1; DeMets et al., 1994) along a NE^ SW-trending subduction interface. The eastern part of the North Island (the forearc ...
The ancestral Cascades arc: Cenozoic evolution of the central
... the southern Sierra compared to the extensive volcanic cover to the north. All these data taken together suggest that the “future plate boundary” represented by the transtensional western Walker Lane belt was born in the axis of the ancestral Cascades arc along the present-day central Sierran range ...
... the southern Sierra compared to the extensive volcanic cover to the north. All these data taken together suggest that the “future plate boundary” represented by the transtensional western Walker Lane belt was born in the axis of the ancestral Cascades arc along the present-day central Sierran range ...
Physical volcanology of the Rooiberg Group near Loskop Dam, By
... It is being submitted for the degree Masters of Science (MSc) in Geology at the University of Pretoria, Pretoria. This thesis has not been submitted before for any degree or examination to any other University. ...
... It is being submitted for the degree Masters of Science (MSc) in Geology at the University of Pretoria, Pretoria. This thesis has not been submitted before for any degree or examination to any other University. ...
d ated 2010
... The exposed portion of the Haib Volcanic Subgroup in the present study area (Fig. 2) consists of acid - intermediate volcanics (rhyolites, dacites, andesites) at the base, overlain by a sequence of andesites, basaltic andesites and minor felsic volcanics. [n order to highlight this rough composition ...
... The exposed portion of the Haib Volcanic Subgroup in the present study area (Fig. 2) consists of acid - intermediate volcanics (rhyolites, dacites, andesites) at the base, overlain by a sequence of andesites, basaltic andesites and minor felsic volcanics. [n order to highlight this rough composition ...
Soriano 2012 Journal of Volcanology and Geothermal Research
... 3.2 Los Frailes Formation The Los Frailes Formation is named for exposures on the lower slopes of Cerro de Los Frailes, but extends farther to the north, west and southwest (Fig. 2). It is mainly composed of dacite breccia, lava and pyroclastic rocks that are pale brown to pale grey and amphibole to ...
... 3.2 Los Frailes Formation The Los Frailes Formation is named for exposures on the lower slopes of Cerro de Los Frailes, but extends farther to the north, west and southwest (Fig. 2). It is mainly composed of dacite breccia, lava and pyroclastic rocks that are pale brown to pale grey and amphibole to ...
Regional Geologic Setting and Volcanic Stratigraphy
... (written communication, 1986) suggests that early volcanism was widespread, with eruptions from many centers over a large portion of the northern Challis field. Dacites were erupted from small composite volcanoes or dome complexes. Basalts and andesites form lava flows and intrusive masses confined ...
... (written communication, 1986) suggests that early volcanism was widespread, with eruptions from many centers over a large portion of the northern Challis field. Dacites were erupted from small composite volcanoes or dome complexes. Basalts and andesites form lava flows and intrusive masses confined ...
Central Anatolian Plateau, Turkey - Tubitak Journals
... The local dendritic drainage system has a significant effect on these soft rock suites (Figure 3). The drainage system is composed of numerous small seasonal and/or sustainable contributing streams, which are joined together and empty out to the main Kızılırmak River in the northern part of the Capp ...
... The local dendritic drainage system has a significant effect on these soft rock suites (Figure 3). The drainage system is composed of numerous small seasonal and/or sustainable contributing streams, which are joined together and empty out to the main Kızılırmak River in the northern part of the Capp ...
pliocene volcanic rocks of the tschicoma formation, east
... The Polvadera Group was believed to be younger than the Keres Group and overlapped it to the south (see Goff and Gardner, 2004 for further discussion). Smith et al. (1970) showed the Tschicoma Formation as an undivided unit that is widely distributed throughout the eastern and northern part of the J ...
... The Polvadera Group was believed to be younger than the Keres Group and overlapped it to the south (see Goff and Gardner, 2004 for further discussion). Smith et al. (1970) showed the Tschicoma Formation as an undivided unit that is widely distributed throughout the eastern and northern part of the J ...
2011 Abstract Volume - California State University, Fullerton
... Faculty Advisor: Professor Brandon Browne Mammoth Mountain is a stratovolcano located in eastern California that was constructed over the past 111ka largely by effusive eruptions of dacite and trachydacite lava flows and domes with textures indicative of mingling between basalt and dacite. Geologic ...
... Faculty Advisor: Professor Brandon Browne Mammoth Mountain is a stratovolcano located in eastern California that was constructed over the past 111ka largely by effusive eruptions of dacite and trachydacite lava flows and domes with textures indicative of mingling between basalt and dacite. Geologic ...
Volcanoes, Magma, and Volcanic Eruptions
... Siliceous Lava Flows - High viscosity andesitic and rhyolitic lava flows, because they can’t flow very easily, form thick stubby flows that don’t move far from the vent. Lava Domes or Volcanic Domes - result from the extrusion of highly viscous, gas poor andesitic and rhyolitic lava. Since the visco ...
... Siliceous Lava Flows - High viscosity andesitic and rhyolitic lava flows, because they can’t flow very easily, form thick stubby flows that don’t move far from the vent. Lava Domes or Volcanic Domes - result from the extrusion of highly viscous, gas poor andesitic and rhyolitic lava. Since the visco ...
the origin of the strjugsskarð andesite, skagi peninsula, north
... the denser dacite on the lower half and more buoyant rhyolite in the upper half. The zoning is not meant to be construed as a strict boundary between the two silicic magmas, but as a gradation from low silica (dacite) on the bottom to high silica (rhyolite) on the top. The PUB may have intruded the ...
... the denser dacite on the lower half and more buoyant rhyolite in the upper half. The zoning is not meant to be construed as a strict boundary between the two silicic magmas, but as a gradation from low silica (dacite) on the bottom to high silica (rhyolite) on the top. The PUB may have intruded the ...
Intrusive vs. Extrusive Volcanic Eruptions
... termed ___________ • Cemented pyroclastic material is termed _____________ • Ash that falls gently from the air is termed an ________________ • Where ash mixes with air it forms a fast moving ________ ______ (nuée ardente) ERSC 2P17 Brock University ...
... termed ___________ • Cemented pyroclastic material is termed _____________ • Ash that falls gently from the air is termed an ________________ • Where ash mixes with air it forms a fast moving ________ ______ (nuée ardente) ERSC 2P17 Brock University ...
Variable eruptive styles in an ancient monogenetic volcanic field
... of volcanology. Pyroclastic rocks are exposed in two quarries and the study was supported with a 30 m deep borehole K1 penetrating these rocks. The pyroclastic rocks are altered but preserved textures enable reconstruction of eruptive styles. The volcanic sequence exposed in the abandoned Hvězda qua ...
... of volcanology. Pyroclastic rocks are exposed in two quarries and the study was supported with a 30 m deep borehole K1 penetrating these rocks. The pyroclastic rocks are altered but preserved textures enable reconstruction of eruptive styles. The volcanic sequence exposed in the abandoned Hvězda qua ...
The Topographic Landscapes of Volcanic Necks in the Coastal
... the coastal Range and in Lutao is highly diversified and these volcanic necks are worthy of permanent preservation simply for tourism and educational purposes. We report 3 typical examples of volcanic conduits occurred in the Coastal Range and Lutao. (1) Haishenping, Lutao: a typical volcanic crater ...
... the coastal Range and in Lutao is highly diversified and these volcanic necks are worthy of permanent preservation simply for tourism and educational purposes. We report 3 typical examples of volcanic conduits occurred in the Coastal Range and Lutao. (1) Haishenping, Lutao: a typical volcanic crater ...
Engineering Geological Properties of the Volcanic Rocks and Soils
... Abstract. This paper analyses the engineering geological properties of the rocks and soils of the Canary Islands based on data from field studies, laboratory tests and extensive databases for vokanic materials. Geological properties and processes most relevant t o geo-engineering are described. Geom ...
... Abstract. This paper analyses the engineering geological properties of the rocks and soils of the Canary Islands based on data from field studies, laboratory tests and extensive databases for vokanic materials. Geological properties and processes most relevant t o geo-engineering are described. Geom ...
GLG 101-Illustrated Vocabulary-Chapter 4 Volcanoes and Plutons C
... lava -is molten rock that has erupted at the earth's surface. lava dome -is a hill-like structure made of viscous magma, formed on top of a composite volcano often following a violent explosive event. The present summit of Mt. St. Helens has one of these structures starting to fill the gap where th ...
... lava -is molten rock that has erupted at the earth's surface. lava dome -is a hill-like structure made of viscous magma, formed on top of a composite volcano often following a violent explosive event. The present summit of Mt. St. Helens has one of these structures starting to fill the gap where th ...
Geological heritage features of Tawau volcanic sequence, Sabah
... Pock. During the early Pleistocene, the main dacite eruptions were from Mt. Maria building a dacitic cone on top of the older eroded andesite (Kirk, 1959). Many steep sided volcanic cones of silicified rocks occur in the main volcanic areas, namely: Mt. Andrassy, Glass Hill, Mt. Lucia and Kinabutan ...
... Pock. During the early Pleistocene, the main dacite eruptions were from Mt. Maria building a dacitic cone on top of the older eroded andesite (Kirk, 1959). Many steep sided volcanic cones of silicified rocks occur in the main volcanic areas, namely: Mt. Andrassy, Glass Hill, Mt. Lucia and Kinabutan ...
Geological heritage features of Tawau volcanic sequence, Sabah
... Pock. During the early Pleistocene, the main dacite eruptions were from Mt. Maria building a dacitic cone on top of the older eroded andesite (Kirk, 1959). Many steep sided volcanic cones of silicified rocks occur in the main volcanic areas, namely: Mt. Andrassy, Glass Hill, Mt. Lucia and Kinabutan ...
... Pock. During the early Pleistocene, the main dacite eruptions were from Mt. Maria building a dacitic cone on top of the older eroded andesite (Kirk, 1959). Many steep sided volcanic cones of silicified rocks occur in the main volcanic areas, namely: Mt. Andrassy, Glass Hill, Mt. Lucia and Kinabutan ...
Geologic Overview of Mount Mazama and the Crater Lake Caldera
... Steep north-trending faults strike parallel to the axis of the Oregon High Cascades and indicate that the range is undergoing east-west extension in this region (Bacon, 1983). A second set of steep north-northwest trending faults strikes into the mountain from the Klamath Lake area to the southeast. ...
... Steep north-trending faults strike parallel to the axis of the Oregon High Cascades and indicate that the range is undergoing east-west extension in this region (Bacon, 1983). A second set of steep north-northwest trending faults strikes into the mountain from the Klamath Lake area to the southeast. ...
explosive eruptions
... • significant effects on explosive activity for vents deeper than ~1000m (depends on magma composition and volatile content) • in relatively shallow water, “wet” explosive activity is common • shallow-water deposits are easily resedimented into deeper water • some pyroclasts are widely dispersed by ...
... • significant effects on explosive activity for vents deeper than ~1000m (depends on magma composition and volatile content) • in relatively shallow water, “wet” explosive activity is common • shallow-water deposits are easily resedimented into deeper water • some pyroclasts are widely dispersed by ...
Geology of the Lassen volcanic area
The geology of the Lassen volcanic area presents a record of sedimentation and volcanic activity in the area in and around Lassen Volcanic National Park in Northern California, U.S. The park is located in the southernmost part of the Cascade Mountain Range in the Pacific Northwest region of the United States. Pacific Oceanic tectonic plates have plunged below the North American Plate in this part of North America for hundreds of millions of years. Heat from these subducting plates has fed scores of volcanoes in California, Oregon, Washington and British Columbia over at least the past 30 million years (see Geology of the Pacific Northwest) and is also responsible for activities in the Lassen volcanic area.Between 3 and 4 million years ago, volcanic-derived mud flows called lahars streamed down several major mountains that included nearby but now extinct Mount Yana and Mount Maidu to become the Tuscan Formation. Basaltic and later andesitic to dacitic flows of lava covered increasingly larger areas of this formation to eventually form the lava plateau that the park sits on. About 600,000 years ago, Mount Tehama started to rise as a stratovolcano in the southwestern corner of the park, eventually reaching an estimated 11,000 ft (3,400 m) in height. Following a series of eruptions approximately 350,000 years ago, its cone collapsed into itself to form a 2 mi (3.2 km) wide caldera. Roughly 27,000 years ago, a dacite lava dome quickly pushed its way through Tehama's destroyed north-eastern flank, becoming the approximately 1,000 ft (300 m) shorter Lassen Peak. Lassen's shape was significantly altered by glacial erosion from 25,000 to 18,000 years ago during the Wisconsin glaciation. Since then, smaller dacite domes such as the 1,100 year-old Chaos Crags have formed around Lassen. Phreatic (steam explosion) eruptions, dacite and andesite lava flows along with cinder cone formation have persisted into modern times. Most notable of these is the mid to late 17th century eruption and formation (Tree Ring dates) of Cinder Cone and the early 20th century eruption of Lassen Peak. The only activity since then has been the constant bubbling of mud pots and steaming of fumaroles from the various geothermal areas in Lassen Volcanic National Park. However, a potential exists for renewed vigorous volcanic activity that could threaten life and property in the area.