Origin of a Rhyolite That Intruded a Geothermal Well While Drilling at the Krafl a Volcano, Iceland
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Iceland Can Be Considered Volcanologist “Heaven”
Iceland can be considered volcanologist “heaven” 1) Sub-aerial continuation of the Mid-Atlantic Ridge 2) Intersection of a mantle plume with a spreading ocean ridge 3) Volcanism associated with tectonic rifting 4) Sub-glacial volcanism 5) Tertiary flood (plateau) basalts 6) Bi-modal volcanism 7) Submarine volcanism 8) 18 historically active volcanoes 9) Eruptions roughly every 5 years 1. The North Atlantic opened about 54 Ma separating Greenland from Europe. 2. Spreading was initially along the now extinct Agir ridge (AER). 3. The Icelandic plume was under Greenland at that time. 4. The Greenland – Faeroe ridge represents the plume track during the history of the NE Atlantic. Kolbeinsey ridge (KR) 5. During the last 20 Ma the Reykjanes Ridge (RR) Icelandic rift zones have migrated eastward, stepwise, maintaining their position near the plume 6. The plume center is thought to be beneath Vatnajökull 1 North Rift Zone – currently active East Rift Zone – currently active West Rift Zone – last erupted about 1000-1300 AD [Also eastern (Oræfajökull) and western (Snæfellsnese) flank zones] Rift zones comprise en-echelon basaltic fissure swarms 5-15 km wide and up to 200 km long. Over time these fissures swarms develop a volcanic center, eventually maturing into a central volcano with a caldera and silicic Tertiary volcanics > 3.1 Ma volcanism Late Tertiary to Early Quaternary 3.1 – 0.7 Ma Neo-volcanic zone <0.7 - present Schematic representation of Iceland’s mantle plume. The crust is about 35 – 40 km thick Iceland’s mantle plume has been tomographically imaged down to 400 km. Some claim even deeper, through the transition zone, and down to the core – mantle boundary. -
Geologic Map of the Simcoe Mountains Volcanic Field, Main Central Segment, Yakama Nation, Washington by Wes Hildreth and Judy Fierstein
Prepared in Cooperation with the Water Resources Program of the Yakama Nation Geologic Map of the Simcoe Mountains Volcanic Field, Main Central Segment, Yakama Nation, Washington By Wes Hildreth and Judy Fierstein Pamphlet to accompany Scientific Investigations Map 3315 Photograph showing Mount Adams andesitic stratovolcano and Signal Peak mafic shield volcano viewed westward from near Mill Creek Guard Station. Low-relief rocky meadows and modest forested ridges marked by scattered cinder cones and shields are common landforms in Simcoe Mountains volcanic field. Mount Adams (elevation: 12,276 ft; 3,742 m) is centered 50 km west and 2.8 km higher than foreground meadow (elevation: 2,950 ft.; 900 m); its eruptions began ~520 ka, its upper cone was built in late Pleistocene, and several eruptions have taken place in the Holocene. Signal Peak (elevation: 5,100 ft; 1,555 m), 20 km west of camera, is one of largest and highest eruptive centers in Simcoe Mountains volcanic field; short-lived shield, built around 3.7 Ma, is seven times older than Mount Adams. 2015 U.S. Department of the Interior U.S. Geological Survey Contents Introductory Overview for Non-Geologists ...............................................................................................1 Introduction.....................................................................................................................................................2 Physiography, Environment, Boundary Surveys, and Access ......................................................6 Previous Geologic -
(2000), Voluminous Lava-Like Precursor to a Major Ash-Flow
Journal of Volcanology and Geothermal Research 98 (2000) 153–171 www.elsevier.nl/locate/jvolgeores Voluminous lava-like precursor to a major ash-flow tuff: low-column pyroclastic eruption of the Pagosa Peak Dacite, San Juan volcanic field, Colorado O. Bachmanna,*, M.A. Dungana, P.W. Lipmanb aSection des Sciences de la Terre de l’Universite´ de Gene`ve, 13, Rue des Maraıˆchers, 1211 Geneva 4, Switzerland bUS Geological Survey, 345 Middlefield Rd, Menlo Park, CA, USA Received 26 May 1999; received in revised form 8 November 1999; accepted 8 November 1999 Abstract The Pagosa Peak Dacite is an unusual pyroclastic deposit that immediately predated eruption of the enormous Fish Canyon Tuff (ϳ5000 km3) from the La Garita caldera at 28 Ma. The Pagosa Peak Dacite is thick (to 1 km), voluminous (Ͼ200 km3), and has a high aspect ratio (1:50) similar to those of silicic lava flows. It contains a high proportion (40–60%) of juvenile clasts (to 3–4 m) emplaced as viscous magma that was less vesiculated than typical pumice. Accidental lithic fragments are absent above the basal 5–10% of the unit. Thick densely welded proximal deposits flowed rheomorphically due to gravitational spreading, despite the very high viscosity of the crystal-rich magma, resulting in a macroscopic appearance similar to flow- layered silicic lava. Although it is a separate depositional unit, the Pagosa Peak Dacite is indistinguishable from the overlying Fish Canyon Tuff in bulk-rock chemistry, phenocryst compositions, and 40Ar/39Ar age. The unusual characteristics of this deposit are interpreted as consequences of eruption by low-column pyroclastic fountaining and lateral transport as dense, poorly inflated pyroclastic flows. -
NE Iceland) Owing to Drone-Based Structure-From-Motion Photogrammetry
applied sciences Article Reconstruction of Late Pleistocene-Holocene Deformation through Massive Data Collection at Krafla Rift (NE Iceland) Owing to Drone-Based Structure-from-Motion Photogrammetry Fabio Luca Bonali 1,2,*, Alessandro Tibaldi 1,2, Noemi Corti 1 , Luca Fallati 1 and Elena Russo 1,2 1 Department of Earth and Environmental Sciences, University of Milan-Bicocca, I-20126 Milan, Italy; [email protected] (A.T.); [email protected] (N.C.); [email protected] (L.F.); [email protected] (E.R.) 2 CRUST-Interuniversity Center for 3D Seismotectonics with Territorial Applications, I-66100 Chieti Scalo, Italy * Correspondence: [email protected]; Tel.: +39-0264482015 Received: 25 August 2020; Accepted: 24 September 2020; Published: 27 September 2020 Abstract: In the present work, we demonstrate how drone surveys coupled with structure-from-motion (SfM) photogrammetry can help to collect huge amounts of very detailed data even in rough terrains where logistics can affect classical field surveys. The area of study is located in the NW part of the Krafla Fissure Swarm (NE Iceland), a volcanotectonic rift composed of eruptive centres, extension fractures, and normal faults. The surveyed sector is characterized by the presence of a hyaloclastite ridge composed of deposits dated, on a stratigraphic basis, to the Weichselian High Glacial (29.1–12.1 ka BP), and a series of lava flows mostly dating back to 11–12 ka BP. The integration of remotely sensed surveys and field inspections enabled us to recognize that this segment of the Krafla rift is made of grabens arranged en-échelon with a left-stepping geometry. -
The Late Oligocene Cieneguilla Basanites, Santa Fe County
New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/62 The late Oligocene Cieneguilla basanites, Santa Fe County: Records of early Rio Grande rift magmatism Jennifer Lindline, Michael Petronis, Rachell Pitrucha, and Salvador Sena, 2011, pp. 235-250 in: Geology of the Tusas Mountains and Ojo Caliente, Author Koning, Daniel J.; Karlstrom, Karl E.; Kelley, Shari A.; Lueth, Virgil W.; Aby, Scott B., New Mexico Geological Society 62nd Annual Fall Field Conference Guidebook, 418 p. This is one of many related papers that were included in the 2011 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks. -
Analogues for Radioactive Waste For~1S •
PNL-2776 UC-70 3 3679 00049 3611 ,. NATURALLY OCCURRING GLASSES: ANALOGUES FOR RADIOACTIVE WASTE FOR~1S • Rodney C. Ewing Richard F. Haaker Department of Geology University of New Mexico Albuquerque, ~ew Mexico 87131 April 1979 Prepared for the U.S. Department of Energy under Contract EY-76-C-06-1830 Pacifi c i'lorthwest Laboratory Richland, Washington 99352 TABLE OF CONTENTS List of Tables. i i List of Figures iii Acknowledgements. Introduction. 3 Natural Glasses 5 Volcanic Glasses 9 Physical Properties 10 Compos i ti on . 10 Age Distributions 10 Alteration. 27 Devitrification 29 Hydration 32 Tekti tes. 37 Physical Properties 38 Composition . 38 Age Distributions . 38 Alteration, Hydration 44 and Devitrification Lunar Glasses 44 Summary . 49 Applications to Radioactive Waste Disposal. 51 Recommenda ti ons 59 References 61 Glossary 65 i LIST OF TABLES 1. Petrographic Properties of Natural Glasses 6 2. Average Densities of Natural Glasses 11 3. Density of Crystalline Rock and Corresponding Glass 11 4. Glass and Glassy Rocks: Compressibility 12 5. Glass and Glassy Rocks: Elastic Constants 13 6. Glass: Effect of Temperature on Elastic Constants 13 7. Strength of Hollow Cylinders of Glass Under External 14 Hydrostatic Pressure 8. Shearing Strength Under High Confining Pressure 14 9. Conductivity of Glass 15 10. Viscosity of Miscellaneous Glasses 16 11. Typical Compositions for Volcanic Glasses 18 12. Selected Physical Properties of Tektites 39 13. Elastic Constants 40 14. Average Composition of Tektites 41 15. K-Ar and Fission-Track Ages of Tektite Strewn Fields 42 16. Microprobe Analyses of Various Apollo 11 Glasses 46 17. -
Lava Shields and Fissure Eruptions of the Western
Journal of Volcanology and Geothermal Research 186 (2009) 331–348 Contents lists available at ScienceDirect Journal of Volcanology and Geothermal Research journal homepage: www.elsevier.com/locate/jvolgeores Lava shields and fissure eruptions of the Western Volcanic Zone, Iceland: Evidence for magma chambers and crustal interaction Deborah E. Eason ⁎, John M. Sinton Department of Geology and Geophysics, School of Ocean and Earth Science and Technology, 1680 East–West Road, University of Hawaii, Honolulu, HI 96822, United States article info abstract Article history: Volcanic eruptions in Iceland occur either from fissures or central vents (lava shields). Within the post-glacial Received 19 December 2008 Western Volcanic Zone, the Thjófahraun fissure-fed lava field and Lambahraun lava shield were both erupted Accepted 30 June 2009 ~4000 yrs B.P. with eruptive centers separated by only ~25 km. Thjófahraun erupted ~1 km3 of pāhoehoe and Available online 5 July 2009 'a'ā lava from a 9-km long fissure, whereas the Lambahraun lava shield erupted N7km3 of low effusion-rate pāhoehoe. Thjófahraun lavas contain higher K, Rb, Y and Zr, and lower CaO than Lambahraun lavas at the same Keywords: MgO, with variations broadly consistent with evolution by low-pressure crystal fractionation. Lambahraun Iceland mid-ocean ridge spans a larger range of MgO, which generally decreases over time during the eruption. Lambahraun samples fl magma chambers with high Al2O3 and low TiO2 and FeO likely re ect up to 15% plagioclase accumulation. In addition, all samples crustal interaction from Lambahraun exhibit increasing CaO and Nb/Zr with decreasing MgO and overall incompatible-element MORB enrichments greater than predicted by crystal fractionation alone. -
USGS Scientific Investigations Map 2832, Pamphlet
Geologic Map of Mount Mazama and Crater Lake Caldera, Oregon By Charles R. Bacon Pamphlet to accompany Scientific Investigations Map 2832 View from the south-southwest rim of Crater Lake caldera showing the caldera wall from Hillman Peak on the west to Cleetwood Cove on the north. Crater Lake fills half of the 8- by 10-km-diameter caldera formed during the climactic eruption of Mount Mazama volcano approximately 7,700 years ago. Volcanic rocks exposed in the caldera walls and on the flanks record over 400,000 years of eruptive history. The exposed cinder cone and andesite lava flows on Wizard Island represent only 2 percent of the total volume of postcaldera volcanic rock that is largely covered by Crater Lake. Beyond Wizard Island, the great cliff of Llao Rock, rhyodacite lava emplaced 100–200 years before the caldera-forming eruption, dominates the northwest caldera wall where andesite lava flows at the lakeshore are approximately 150,000 years old. 2008 U.S. Department of the Interior U.S. Geological Survey This page intentionally left blank. CONTENTS Introduction . 1 Physiography and access . 1 Methods . 1 Geologic setting . 4 Eruptive history . 5 Regional volcanism . 6 Pre-Mazama silicic rocks . 6 Mount Mazama . 7 Preclimactic rhyodacites . 9 The climactic eruption . 10 Postcaldera volcanism . .11 Submerged caldera walls and floor . .11 Glaciation . .11 Geothermal phenomena . 12 Hazards . 13 Volcanic hazards . 13 Earthquake hazards . 14 Acknowledgments . 14 Description of map units . 14 Sedimentary deposits . 15 Volcanic rocks . 15 Regional volcanism, northwest . 15 Regional volcanism, southwest . 17 Mount Mazama . 20 Regional volcanism, east . 38 References cited . -
Rock and Mineral Identification for Engineers
Rock and Mineral Identification for Engineers November 1991 r~ u.s. Department of Transportation Federal Highway Administration acid bottle 8 granite ~~_k_nife _) v / muscovite 8 magnify~in_g . lens~ 0 09<2) Some common rocks, minerals, and identification aids (see text). Rock And Mineral Identification for Engineers TABLE OF CONTENTS Introduction ................................................................................ 1 Minerals ...................................................................................... 2 Rocks ........................................................................................... 6 Mineral Identification Procedure ............................................ 8 Rock Identification Procedure ............................................... 22 Engineering Properties of Rock Types ................................. 42 Summary ................................................................................... 49 Appendix: References ............................................................. 50 FIGURES 1. Moh's Hardness Scale ......................................................... 10 2. The Mineral Chert ............................................................... 16 3. The Mineral Quartz ............................................................. 16 4. The Mineral Plagioclase ...................................................... 17 5. The Minerals Orthoclase ..................................................... 17 6. The Mineral Hornblende ................................................... -
A CIRCUMNAVIGATION of ICELAND 2022 Route: Reykjavik, Iceland to Reykjavik, Iceland
A CIRCUMNAVIGATION OF ICELAND 2022 route: Reykjavik, Iceland to Reykjavik, Iceland 11 Days NG Explorer - 148 Guests National Geographic Resolution - 126 Guests Expeditions in: Jul/Aug From $11,920 to $29,610 * Iceland’s geology in all its manifestations––glaciers, geysers, thundering waterfalls, immense cliffs, geothermal springs, boiling mud pots, and rock and lava-scapes of unearthly beauty––is world-class. It alone makes a circumnavigation a very compelling idea. And when you add in the other itinerary components––Iceland’s people, their unique cultural heritage and contemporary character, the island’s geography and birdlife––seeing it all in one 360º expedition is irresistible. Call us at 1.800.397.3348 or call your Travel Agent. In Australia, call 1300.361.012 • www.expeditions.com DAY 1: Reykjavik / Embark padding Arrive in Reykjavík, the world’s northernmost capital, which lies only a fraction below the Arctic Circle and receives just four hours of sunlight in 2022 Departure Dates: winter and 22 in summer. Have a panoramic overview of the Old Town, including 21 Jun Hallgrímskirkja Cathedral with its 210-foot tower, 13 Jul, 22 Jul and perhaps shed some light on Nordic culture at 2023 Departure Dates: the National Museum, with its Viking treasures, artifacts, and unusual whalebone carvings on 3 Jul, 12 Jul, 21 Jul display. Embark National Geographic Resolution. (L,D) Important Flight Information Please confirm arrival and departure dates prior to booking flights. DAY 2: Flatey Island padding Explore Iceland’s western frontier, visiting Flatey Advance Payment: Island, a trading post for many centuries, for walks around the charming little hamlet that grew here, $1,500 and take a Zodiac cruise along the coast. -
Monitoring Volcanoes in Iceland and Their Current Status
Monitoring volcanoes in Iceland and their current status Sara Barsotti Coordinator for Volcanic Hazards, [email protected] Overview • Volcanoes and volcanic eruption styles in Iceland • Monitoring volcanoes and volcanic eruptions • Current status at • Hekla • Katla • Bárðarbunga • Grímsvötn • Öræfajökull 2 The catalogue of Icelandic Volcanoes – icelandicvolcanoes.is It includes historical activity, current seismicity, possible hazards and scenarios, GIS-based map layers to visualize eruption product extensions (lava flows, ash deposits) – ICAO project 3 Explosive vs. Effusive eruption Eyjafjallajökull 2010 Bárðarbunga - Holuhraun 2014-2015 • Volcanic cloud (possibly up to • Lava flow the stratosphere) • Volcanic gas into the • Tephra fallout atmosphere (hardly higher • Lightning than the tropopause) • Floods (if from ice-capped volcano) • Pyroclastic flows 4 Volcanic ash hazards from Icelandic volcanoes All these volcanoes have volcanic ash as one of the principal hazards 5 Eruption in Iceland since 1913 Year Volcano VEI Note Stile of activity 2014 Holuhraun (Bárðarbunga) 1 Effusive 2011 Grímsvötn 4 Ice Explosive 2010 Eyjafjallajökull 3 Ice Explosive/effusive 2004 Grímsvötn 3 Ice Explosive 2000 Hekla 3 Effusive/explosive 1998 Grímsvötn 3 Ice Explosive 1996 Gjálp (Grímsvötn) 3 Ice Subglacial-explosive 1991 Hekla 3 Effusive/explosive 1983 Grímsvötn 2 Ice Explosive 1980-81 Hekla 3 Effusive/explosive 1975-84 Krafla fires (9 eruptions) 1 Effusive 1973 Heimaey 2 Effusive/explosive 1970 Hekla 3 Effusive/explosive Instrumental monitoring 1963-67 -
The Fissure Swarm of the Askja Central Volcano
University of Iceland – Faculty of Science – Department of Geosciences The fissure swarm of the Askja central volcano by Ásta Rut Hjartardóttir A thesis submitted to the University of Iceland for the degree of Master of Science in Geophysics Supervisors: Páll Einarsson, University of Iceland Haraldur Sigurðsson, University of Rhode Island May, 2008 The fissure swarm of the Askja central volcano ©2008 Ásta Rut Hjartardóttir ISBN 978-9979-9633-5-6 Printed by Nón ii Hér með lýsi ég því yfir að ritgerð þessi er samin af mér og að hún hefur hvorki að hluta né í heild verið lögð fram áður til hærri prófgráðu. _______________________________ Ásta Rut Hjartardóttir iii iv Abstract The Askja volcanic system forms one of the 5-6 volcanic systems of the Northern Volcanic Zone, that divides the North-American and the Eurasian plates. Historical eruptions have occurred both within the central volcano and in its fissure swarm. As an example, repeated fissure eruptions occurred in the fissure swarm, and a Plinian eruption occurred within the volcano itself in 1875. This led to the formation of the youngest caldera in Iceland, which now houses the Lake Öskjuvatn. Six eruptions occurred in the 1920„s and one in 1961 in Askja. No historical accounts have, however, been found of eruptive activity of Askja before 1875, likely due to its remote location. To improve the knowledge of historic and prehistoric activity of Askja, we mapped volcanic fissures and tectonic fractures within and north of the Askja central volcano. The 1800 km2 area included as an example Mt. Herðubreið, Mt.