Episodic Triggering of the Rise of Resident Small-Scale Basaltic Magmas from the Mantle
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Volcanic Landforms: the Landform Which Is Formed from the Material Thrown out to the Surface During Volcanic Activity Is Called Extrusive Landform
Download Testbook App Volcanic Geography NCERT Notes Landforms For UPSC ABOUT VOLCANIC LANDFORM: Volcanic landform is categorised into two types they are:extrusive and intrusive landforms. This division is done based on whether magma cools within the crust or above the crust. By the cooling process of magma different types of rock are formed. Like: Plutonic rock, it is a rock which is magma within the crust whereas Igneous rock is formed by the cooling of lava above the surface. Along with that “igneous rock” term is also used to refer to all rocks of volcanic origin. Extrusive Volcanic Landforms: The landform which is formed from the material thrown out to the surface during volcanic activity is called extrusive landform. The materials which are thrown out during volcanic activity are: lava flows, pyroclastic debris, volcanic bombs, ash, dust and gases such as nitrogen compounds, sulphur compounds and minor amounts of chlorine, hydrogen and argon. Conical Vent and Fissure Vent: Conical Vent: It is a narrow cylindrical vent through which magma flows out violently. Such vents are commonly seen in andesitic volcanism. Fissure vent: Such vent is a narrow, linear through which lava erupts with any kind of explosive events. Such vents are usually seen in basaltic volcanism. Mid-Ocean Ridges: The volcanoes which are found in oceanic areas are called mid-ocean ridges. In them there is a system of mid-ocean ridges stretching for over 70000 km all through the ocean basins. And the central part of such a ridge usually gets frequent eruptions. Composite Type Volcanic Landforms: Such volcanic landforms are also called stratovolcanoes. -
Chapter 10: Mantle Melting and the Generation of Basaltic Magma 2 Principal Types of Basalt in the Ocean Basins Tholeiitic Basalt and Alkaline Basalt
Chapter 10: Mantle Melting and the Generation of Basaltic Magma 2 principal types of basalt in the ocean basins Tholeiitic Basalt and Alkaline Basalt Table 10.1 Common petrographic differences between tholeiitic and alkaline basalts Tholeiitic Basalt Alkaline Basalt Usually fine-grained, intergranular Usually fairly coarse, intergranular to ophitic Groundmass No olivine Olivine common Clinopyroxene = augite (plus possibly pigeonite) Titaniferous augite (reddish) Orthopyroxene (hypersthene) common, may rim ol. Orthopyroxene absent No alkali feldspar Interstitial alkali feldspar or feldspathoid may occur Interstitial glass and/or quartz common Interstitial glass rare, and quartz absent Olivine rare, unzoned, and may be partially resorbed Olivine common and zoned Phenocrysts or show reaction rims of orthopyroxene Orthopyroxene uncommon Orthopyroxene absent Early plagioclase common Plagioclase less common, and later in sequence Clinopyroxene is pale brown augite Clinopyroxene is titaniferous augite, reddish rims after Hughes (1982) and McBirney (1993). Each is chemically distinct Evolve via FX as separate series along different paths Tholeiites are generated at mid-ocean ridges Also generated at oceanic islands, subduction zones Alkaline basalts generated at ocean islands Also at subduction zones Sources of mantle material Ophiolites Slabs of oceanic crust and upper mantle Thrust at subduction zones onto edge of continent Dredge samples from oceanic crust Nodules and xenoliths in some basalts Kimberlite xenoliths Diamond-bearing pipes blasted up from the mantle carrying numerous xenoliths from depth Lherzolite is probably fertile unaltered mantle Dunite and harzburgite are refractory residuum after basalt has been extracted by partial melting 15 Tholeiitic basalt 10 5 Figure 10-1 Brown and Mussett, A. E. (1993), The Inaccessible Earth: An Integrated View of Its Lherzolite Structure and Composition. -
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Sarah Lambart - 2016 Recap Lecture 16: Isotopes 101 • Radioactive (parent) vs. radiogenic (daugher) isotopes • Unstable (radioactive) vs stable isotopes • Uses: for dating (geochronology) and as tracers (source composition) Recap Lecture 16: Isotopes 101 • As tracers: • Ex.: 87Sr/86Sr: DMM < co < cc High Rb/Sr c.c. Crust evolution o.c. 87Sr 86Sr melting event DMM Low Rb/Sr Mantle Primitive Mantle/BSE Depleted mantle evolution € 4.55 b.y. Time -> today Recap Lecture 16: Isotopes 101 • As tracers: • Ex.: 87Sr/86Sr: DMM < co < cc • Isotopes do not fractionate during partial melting and crystallization processes!!! ⇒ 87Sr/86Sr (source) = 87Sr/86Sr (magma) ⇒ if 87Sr/86Sr (magma) ≠ constant ⇒ several source components (subducted oc, subducted sediments, subcontinental lithosphere, ect…) or crustal contamination (AFC) Mid-Ocean Ridges Basalt (MORB) • Facts: • Oceanic floors: 60% of Earth’s surface • Most of the rocks produced at ridges are MORB • Large compositional variability 3) Source composition 2) Melting conditions (Pressure, Temperature) 4) Melt segregation and transport 1) Magma differentiation/crystallization Structure of Mid-Ocean Ridges • Ridges: submarine (most of the time) mountain chains ≈ 3000m Slow-spreading ridge: Fast-spreading ridge: Ex.: Mid-Atltantic ridge : 2cm/yr Ex.: EPR: 10 cm/yr Fig. 13-15 in Winters Structure of Mid-Ocean Ridges • Ridges: submarine (most of the time) mountain chains ≈ 3000m Slow-spreading ridge: Fast-spreading ridge: Ex.: Mid-Atltantic ridge : 2cm/yr Ex.: EPR: 10 cm/yr - Spreading rate: 8-10 cm/yr - Spreading rate: <5 cm/yr - Axial uplift = horst - Axial valley = rift (relief = 300m) - Bigger magma reservoir ⇒ more differentiation - Numerous normal faults: active seismic zone - Small multiple magma reservoirs? The oceanic lithosphere • Maturation d(m) = 2500 + 350 T1/2 (Ma) Fig. -
Magma Emplacement and Deformation in Rhyolitic Dykes: Insight Into Magmatic Outgassing
MAGMA EMPLACEMENT AND DEFORMATION IN RHYOLITIC DYKES: INSIGHT INTO MAGMATIC OUTGASSING Presented for the degree of Ph.D. by Ellen Marie McGowan MGeol (The University of Leicester, 2011) Initial submission January 2016 Final submission September 2016 Lancaster Environment Centre, Lancaster University Declaration I, Ellen Marie McGowan, hereby declare that the content of this thesis is the result of my own work, and that no part of the work has been submitted in substantially the same form for the award of a higher degree elsewhere. This thesis is dedicated to Nan-Nar, who sadly passed away in 2015. Nan, you taught our family the importance and meaning of love, we love you. Abstract Exposed rhyolitic dykes at eroded volcanoes arguably provide in situ records of conduit processes during rhyolitic eruptions, thus bridging the gap between surface and sub-surface processes. This study involved micro- to macro-scale analysis of the textures and water content within shallow (emplacement depths <500 m) rhyolitic dykes at two Icelandic central volcanoes. It is demonstrated that dyke propagation commenced with the intrusion of gas- charged currents that were laden with particles, and that the distribution of intruded particles and degree of magmatic overpressure required for dyke propagation were governed by the country rock permeability and strength, with pre-existing fractures playing a pivotal governing role. During this stage of dyke evolution significant amounts of exsolved gas may have escaped. Furthermore, during later magma emplacement within the dyke interiors, particles that were intruded and deposited during the initial phase were sometimes preserved at the dyke margins, forming dyke- marginal external tuffisite veins, which would have been capable of facilitating persistent outgassing during dyke growth. -
Video Monitoring Reveals Pulsating Vents and Propagation Path of Fissure Eruption During the March 2011 Pu'u
Journal of Volcanology and Geothermal Research 330 (2017) 43–55 Contents lists available at ScienceDirect Journal of Volcanology and Geothermal Research journal homepage: www.elsevier.com/locate/jvolgeores Video monitoring reveals pulsating vents and propagation path of fissure eruption during the March 2011 Pu'u 'Ō'ō eruption, Kilauea volcano Tanja Witt ⁎,ThomasR.Walter GFZ German Research Centre for Geosciences, Section 2.1: Physics of Earthquakes and Volcanoes, Telegrafenberg, 14473 Potsdam, Germany article info abstract Article history: Lava fountains are a common eruptive feature of basaltic volcanoes. Many lava fountains result from fissure erup- Received 12 April 2016 tions and are associated with the alignment of active vents and rising gas bubbles in the conduit. Visual reports Received in revised form 18 November 2016 suggest that lava fountain pulses may occur in chorus at adjacent vents. The mechanisms behind such a chorus of Accepted 18 November 2016 lava fountains and the underlying processes are, however, not fully understood. Available online 5 December 2016 The March 2011 eruption at Pu'u 'Ō'ō (Kilauea volcano) was an exceptional fissure eruption that was well mon- fi fi Keywords: itored and could be closely approached by eld geologists. The ssure eruption occurred along groups of individ- Kilauea volcano ual vents aligned above the feeding dyke. We investigate video data acquired during the early stages of the Fissure eruption eruption to measure the height, width and velocity of the ejecta leaving eight vents. Using a Sobel edge-detection Vent migration algorithm, the activity level of the lava fountains at the vents was determined, revealing a similarity in the erup- Bubbling magma tion height and frequency. -
LERZ) Eruption of Kīlauea Volcano: Fissure 8 Prognosis and Ongoing Hazards
COOPERATOR REPORT TO HAWAII COUNTY CIVIL DEFENSE Preliminary Analysis of the ongoing Lower East Rift Zone (LERZ) eruption of Kīlauea Volcano: Fissure 8 Prognosis and Ongoing Hazards Prepared by the U.S. Geological Survey Hawaiian Volcano Observatory July 15, 2018 (V 1.1) Introduction In late April 2018, the long-lived Puʻu ʻŌʻō vent collapsed, setting off a chain of events that would result in a vigorous eruption in the lower East Rift Zone of Kīlauea Volcano, as well as the draining of the summit lava lake and magmatic system and the subsequent collapse of much of the floor of the Kīlauea caldera. Both events originated in Lava Flow Hazard Zone (LFHZ) 1 (Wright et al, 1992), which encompasses the part of the volcano that is most frequently affected by volcanic activity. We examine here the possible and potential impacts of the ongoing eruptive activity in the lower East Rift Zone (LERZ) of Kīlauea Volcano, and specifically that from fissure 8 (fig. 1). Fissure 8 has been the dominant lava producer during the 2018 LERZ eruption, which began on May 3, 2018, in Leilani Estates, following intrusion of magma from the middle and upper East Rift Zone, as well as the volcano’s summit, into the LERZ. The onset of downrift intrusion was accompanied by collapse of the Puʻu ʻŌʻō vent, which started on April 30 and lasted several days. Kīlauea Volcano's shallow summit magma reservoir began deflating on about May 2, illustrating the magmatic connection between the LERZ and the summit. Early LERZ fissures erupted cooler lava that had likely been stored within the East Rift Zone, but was pushed out in front of hotter magma arriving from farther uprift. -
29. Sulfur Isotope Ratios of Leg 126 Igneous Rocks1
Taylor, B., Fujioka, K., et al., 1992 Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 126 29. SULFUR ISOTOPE RATIOS OF LEG 126 IGNEOUS ROCKS1 Peter Torssander2 ABSTRACT Sulfur isotope ratios have been determined in 19 selected igneous rocks from Leg 126. The δ34S of the analyzed rocks ranges from -0.1 o/00 to +19.60 o/oo. The overall variation in sulfur isotope composition of the rocks is caused by varying degrees of seawater alteration. Most of the samples are altered by seawater and only five of them are considered to have maintained their magmatic sulfur isotope composition. These samples are all from the backarc sites and have δ34S values varying from +0.2 o/oo to +1.6 o/oo , of which the high δ34S values suggest that the earliest magmas in the rift are more arc-like in their sulfur isotope composition than the later magmas. The δ34S values from the forearc sites are similar to or heavier than the sulfur isotope composition of the present arc. INTRODUCTION from 0 o/oo to +9 o/00 (Ueda and Sakai, 1984), which could arise from inhomogeneities in the mantle but are more likely a result of contami- Sulfur is a volatile element that can be degassed during the ascent nation from the subducting slab (A. Ueda, pers. comm., 1988). of basaltic magma. Degassing causes sulfur isotope fractionation; the Leg 126 of the Ocean Drilling Program (ODP) drilled seven sites isotopic composition of sulfur in rocks can vary with the concentra- in the backarc and forearc of the Izu-Bonin Arc (Fig. -
Lunar Crater Volcanic Field (Reveille and Pancake Ranges, Basin and Range Province, Nevada, USA)
Research Paper GEOSPHERE Lunar Crater volcanic field (Reveille and Pancake Ranges, Basin and Range Province, Nevada, USA) 1 2,3 4 5 4 5 1 GEOSPHERE; v. 13, no. 2 Greg A. Valentine , Joaquín A. Cortés , Elisabeth Widom , Eugene I. Smith , Christine Rasoazanamparany , Racheal Johnsen , Jason P. Briner , Andrew G. Harp1, and Brent Turrin6 doi:10.1130/GES01428.1 1Department of Geology, 126 Cooke Hall, University at Buffalo, Buffalo, New York 14260, USA 2School of Geosciences, The Grant Institute, The Kings Buildings, James Hutton Road, University of Edinburgh, Edinburgh, EH 3FE, UK 3School of Civil Engineering and Geosciences, Newcastle University, Newcastle, NE1 7RU, UK 31 figures; 3 tables; 3 supplemental files 4Department of Geology and Environmental Earth Science, Shideler Hall, Miami University, Oxford, Ohio 45056, USA 5Department of Geoscience, 4505 S. Maryland Parkway, University of Nevada Las Vegas, Las Vegas, Nevada 89154, USA CORRESPONDENCE: gav4@ buffalo .edu 6Department of Earth and Planetary Sciences, 610 Taylor Road, Rutgers University, Piscataway, New Jersey 08854-8066, USA CITATION: Valentine, G.A., Cortés, J.A., Widom, ABSTRACT some of the erupted magmas. The LCVF exhibits clustering in the form of E., Smith, E.I., Rasoazanamparany, C., Johnsen, R., Briner, J.P., Harp, A.G., and Turrin, B., 2017, overlapping and colocated monogenetic volcanoes that were separated by Lunar Crater volcanic field (Reveille and Pancake The Lunar Crater volcanic field (LCVF) in central Nevada (USA) is domi variable amounts of time to as much as several hundred thousand years, but Ranges, Basin and Range Province, Nevada, USA): nated by monogenetic mafic volcanoes spanning the late Miocene to Pleisto without sustained crustal reservoirs between the episodes. -
Proquest Dissertations
OXIDATION AND METASOMATISM OF LITHOSPHERIC MANTLE BENEATH THE SOUTHERN SOUTH AMERICA by Jian Wang, B.Sc, M.Sc. Thesis submitted to the Faculty of Graduate & Postdoctoral Studies in partial fulfillment of the requirements for the Ph.D. degree in the Earth Sciences Ottawa-Carleton Geoscience Centre and University of Ottawa Ottawa, Canada May, 2007 © 2007 Jian Wang Library and Bibliotheque et 1*1 Archives Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A0N4 Ottawa ON K1A0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-49403-5 Our file Notre reference ISBN: 978-0-494-49403-5 NOTICE: AVIS: The author has granted a non L'auteur a accorde une licence non exclusive exclusive license allowing Library permettant a la Bibliotheque et Archives and Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par Plntemet, prefer, telecommunication or on the Internet, distribuer et vendre des theses partout dans loan, distribute and sell theses le monde, a des fins commerciales ou autres, worldwide, for commercial or non sur support microforme, papier, electronique commercial purposes, in microform, et/ou autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in et des droits moraux qui protege cette these. this thesis. Neither the thesis Ni la these ni des extraits substantiels de nor substantial extracts from it celle-ci ne doivent etre imprimes ou autrement may be printed or otherwise reproduits sans son autorisation. -
Assessing Eruption Column Height in Ancient Flood Basalt Eruptions
This is a repository copy of Assessing eruption column height in ancient flood basalt eruptions. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/109782/ Version: Accepted Version Article: Glaze, LS, Self, S, Schmidt, A orcid.org/0000-0001-8759-2843 et al. (1 more author) (2017) Assessing eruption column height in ancient flood basalt eruptions. Earth and Planetary Science Letters, 457. pp. 263-270. ISSN 0012-821X https://doi.org/10.1016/j.epsl.2014.07.043 © 2016 Elsevier B.V. and United States Government as represented by the Administrator of the National Aeronautics and Space Administration. Published by Elsevier B.V. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version - refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher’s website. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. -
Controls on Lunar Basaltic Volcanic Eruption Structure and Morphology: 2 Gas Release Patterns in Sequential Eruption Phases 3 L
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Lancaster E-Prints 1 Controls on Lunar Basaltic Volcanic Eruption Structure and Morphology: 2 Gas Release Patterns in Sequential Eruption Phases 3 L. Wilson1,2 and J. W. Head2 4 1Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK 5 2Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 6 02912 USA 7 8 Key Points: 9 Relationships between a diverse array of lunar mare effusive and explosive volcanic 10 deposits and landforms have previously been poorly understood. 11 Four stages in the generation, ascent and eruption of magma and gas release patterns are 12 identified and characterized. 13 Specific effusive, explosive volcanic deposits and landforms are linked to these four 14 stages in lunar mare basalt eruptions in a predictive and integrated manner. 15 16 Abstract 17 Assessment of mare basalt gas release patterns during individual eruptions provides the basis for 18 predicting the effect of vesiculation processes on the structure and morphology of associated 19 features. We subdivide typical lunar eruptions into four phases: Phase 1, dike penetrates to the 20 surface, transient gas release phase; Phase 2, dike base still rising, high flux hawaiian eruptive 21 phase; Phase 3, dike equilibration, lower flux hawaiian to strombolian transition phase; Phase 4, 22 dike closing, strombolian vesicular flow phase. We show how these four phases of mare basalt 23 volatile release, together with total dike volumes, initial magma volatile content, vent 24 configuration and magma discharge rate, can help relate the wide range of apparently disparate 25 lunar volcanic features (pyroclastic mantles, small shield volcanoes, compound flow fields, 26 sinuous rilles, long lava flows, pyroclastic cones, summit pit craters, irregular mare patches 27 (IMPs) and ring moat dome structures (RMDSs)) to a common set of eruption processes. -
LETTER Doi:10.1038/Nature10326
LETTER doi:10.1038/nature10326 An ancient recipe for flood-basalt genesis Matthew G. Jackson1 & Richard W. Carlson2 Large outpourings of basaltic lava have punctuated geological (LIPs)—volcanic provinces characterized by anomalously high rates of time, but the mechanisms responsible for the generation of such mantle melting that represent the largest volcanic events in the Earth’s extraordinary volumes of melt are not well known1. Recent geo- history—to determine whether they are associated with a primitive chemical evidence suggests that an early-formed reservoir may (albeit non-chondritic) mantle source. have survived in the Earth’s mantle for about 4.5 billion years Located in the southwestern Pacific, the Ontong Java Plateau (OJP) (ref. 2), and melts of this reservoir contributed to the flood basalt is the largest LIP on the Earth1,6,7. The average e143Nd(t) of these emplaced on Baffin Island about 60 million years ago3–5. However, lavas6,7 plots close to the BIWG lavas (Fig. 1) and within the range the volume of this ancient mantle domain and whether it has con- predicted for the non-chondritic primitive mantle. Excluding the most tributed to other flood basalts is not known. Here we show that incompatible and fluid mobile elements, the OJP lavas have relatively basalts from the largest volcanic event in geologic history—the flat primitive-mantle-normalized trace-element patterns (Fig. 2) sim- Ontong Java plateau1,6,7—also exhibit the isotopic and trace ilar to the relatively flat patterns identified in the two highest 3He/4He element signatures proposed for the early-Earth reservoir2.