DOCSLIB.ORG

Magma Storage and Plumbing of Adakite-Type Post-Ophiolite Intrusions

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Magma Storage and Plumbing of Adakite-Type Post-Ophiolite Intrusions Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Solid Earth Discuss., 6, 2321–2370, 2014 www.solid-earth-discuss.net/6/2321/2014/ doi:10.5194/sed-6-2321-2014 SED © Author(s) 2014. CC Attribution 3.0 License. 6, 2321–2370, 2014 This discussion paper is/has been under review for the journal Solid Earth (SE). Magma storage and Please refer to the corresponding final paper in SE if available. plumbing of adakite-type Magma storage and plumbing of post-ophiolite intrusions adakite-type post-ophiolite intrusions in K. Jamshidi et al. the Sabzevar ophiolitic zone, NE Iran Title Page K. Jamshidi1,2, H. Ghasemi1, V. R. Troll2, M. Sadeghian1, and B. Dahren2 Abstract Introduction 1Faculty of Earth Sciences, Shahrood University, Shahrood, Iran 2Department of Earth Sciences, CEMPEG, Uppsala University, Uppsala, Sweden Conclusions References Received: 24 July 2014 – Accepted: 24 July 2014 – Published: 8 August 2014 Tables Figures Correspondence to: K. Jamshidi ([email protected]) J I Published by Copernicus Publications on behalf of the European Geosciences Union. J I Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion 2321 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Abstract SED Subduction-related adakite-type intrusive rocks emplaced into the late Cretaceous- Paleocene Sabzevar ophiolite zone, NE Iran, range from Mg-andesite to rhyodacite 6, 2321–2370, 2014 in composition. Here we investigate the magma supply system to these subvolcanic 5 intrusive rocks by applying thermobarometric mineral and mineral-melt equilibrium Magma storage and models, including amphibole thermobarometry, plagioclase-melt thermobarometry and plumbing of clinopyroxene-melt barometry. Based on the results of these thermobarometric models, adakite-type plagioclase crystallized dominantly at pressures of ∼ 350 (468–130) MPa, while amphi- post-ophiolite boles record both low pressures (∼ 300 MPa) and very high pressures (> 700 MPa) of intrusions 10 crystallization. The latter is supported by the calculated pressures for clinopyroxene crystallization (550 to 730 MPa). The association of amphibole with clinopyroxene and K. Jamshidi et al. no plagioclase in the most primitive samples (Mg-andesites) is consistent with am- phibole fractionation from very hydrous magmas at deep crustal levels of the plumb- ing system, which may have been a key process to intensify adakite-type affinities Title Page 15 in this rock suite. Barometry, combined with frequent disequilibrium features, such as Abstract Introduction oscillatory-zoned and sieve-textured plagioclase crystals with An-rich overgrowths in more evolved samples, imply final magma differentiation occurred in an open upper Conclusions References crustal magma system that developed progressively stronger compositional modifica- Tables Figures tions during high-level magma storage. J I 20 1 Introduction J I The Sabzevar ophiolitic zone (SOZ) in northeast Iran is part of the eastern Tethyan Back Close ophiolite belt and represents a remnant of the Cretaceous Tethyan ocean lithosphere Full Screen / Esc which was obducted in late Cretaceous to early Paleocene time (Shojaat et al., 2003). The ophiolite belt contains ultramafic rocks (harzburgite, dunite and lherzolite), small Printer-friendly Version 25 masses of gabbro, and a thick sequence of submarine basaltic lavas (Shojaat et al., 2003; Khalatbari Jafari et al., 2013). The ophiolite is intruded by widespread subvol- Interactive Discussion 2322 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | canic stocks and dykes of intermediate to felsic compositions and the main purpose of this study is to investigate the compositional spectrum and ascent history of these SED post-ophiolite subvolcanic rocks. 6, 2321–2370, 2014 The detailed evolution and ascent history of the Sabzevar post-ophiolite rocks has 5 not been investigated previously and we present new major and trace element data on whole rocks plus major element data from the main minerals to improve our knowledge Magma storage and on the history of the post-ophiolite intrusive suite. We attempt to compare post-ophiolite plumbing of felsic rocks in the southern Sabzevar belt with dominantly intermediate ones in the adakite-type North and aim to test if differences between the post-ophiolite subvolcanic rocks of the post-ophiolite 10 two sectors exist. Finally, we hope to establish the P -T conditions of amphibole and intrusions plagioclase crystallization through mineral-melt equilibrium thermobarometry to help reconstruct the former plumbing system to these rocks. K. Jamshidi et al. Amphibole occurs as essential rock forming mineral in a wide variety of igneous and metamorphic rocks and is especially abundant in calc-alkaline igneous rocks. Experi- Title Page 15 mental studies have synthesized amphibole over a pressure range of up to 2300 MPa ◦ ◦ and 400 C to 1150 C in calc-alkaline compositions (Blundy and Holland, 1990) and Abstract Introduction amphibole has therefore considerable potential as an indicator of crystallization condi- Conclusions References tions, both as geothermometer and geobarometer (Blundy and Holland, 1990; Ridolfi, 2010). Tables Figures 20 The composition and growth morphology of igneous feldspar usually reflects pro- gressive changes in crystallization conditions that give a reliable record of crystalliza- J I tion dynamics of an associated melt and its thermal and compositional history (e.g. Troll and Schmincke, 2002; Slaby and Götze, 2004). In the studied rocks, amphibole and J I plagioclase are found most widely in the northern suite of intermediate rocks and we Back Close 25 employed the thermobarometers of Ridolfi and Renzulli (2012) for selected amphiboles Full Screen / Esc to determine crystallization and storage conditions for these rocks. Plagioclase-liquid thermobarometry (Putirka, 2008) and clinopyroxene-melt barometry (Putirka, 2008) Printer-friendly Version were employed in order to complement and test the results from amphibole thermo- barometry. Interactive Discussion 2323 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 2 Geological setting SED The Sabzevar ophiolite zone is ∼ 200 km long and ∼ 10 km wide and represents a tec- tonically dismembered ophiolite complex, located along the northern boundary of the 6, 2321–2370, 2014 Central Iranian microcontinent (Shojaat et al., 2003). Plate tectonic reconstructions 5 suggest that the Sabzevar ophiolite was part of the Tethyan Ocean that formed during Magma storage and Cretaceous rifting from a narrow but deep seaway, separating the Central Iranian mi- plumbing of crocontinent from the Eurasian plate. The ophiolite was emplaced during an episode adakite-type of northeast dipping subduction (i.e. closure) of the Tethyan seaway (the Sabzevar post-ophiolite Ocean) in Upper Cretaceous–early Paleocene time (Shojaat et al., 2003). The em- intrusions 10 placement of the Sabzevar ophiolitic belt was followed by lasting post-ophiolite volcan- ism from at least the Eocene (∼ 40 Ma) to the end of the Pliocene (∼ 2.3 Ma) (Lensch K. Jamshidi et al. et al., 1977; Spies et al., 1983; Shojaat et al., 2003). This Eocene volcanism is ex- pressed in central and in northern Iran (Berberian and King, 1981; Berberian et al., 1982; Bina et al., 1986; Stampfli and Borel, 2002; Agard et al., 2005; Shabanian et al., Title Page 15 2012) and Eocene volcano-sedimentary rocks cover extensive areas in the Sabzevar Abstract Introduction region. Since the Oligocene, volcanism has been intermittent (Jahangiri, 2007) and, for ∼ 10 Ma focussed predominantly on the Turkish-Iranian plateau (e.g., Berberian and Conclusions References Berberian, 1981; Keskin et al., 1998; Azizi and Moinevaziri, 2009). The Oligo-Miocene Tables Figures sedimentary rocks are composed of marine flysch-type facies in their lower parts, while 20 younger facies are of continental origin and contain, in some parts, extremely high per- J I centages of volcanic detritus. These sedimentary rocks are tectonically imbricated, often steeply dipping and penetrated by Oligocene alkali-olivine-basalt magmatism J I (Ghasemi et al., 2011). Following the Eocene volcanic and volcano-sedimentary and Back Close the Oligocene volcanic activity, magmatism recommenced in the region and continued Full Screen / Esc 25 to the end of the Pliocene. In the Sabzevar belt, characteristically, post-ophiolite subvol- canic rocks occur in the north and in the south of the ophiolite zone (Fig. 1) and mag- matism comprised intermediate rocks in the northern part, while felsic rocks dominate Printer-friendly Version the southern part (Fig. 2). Fragments of host rocks, including serpentinized harzbur- Interactive Discussion 2324 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | gites, tuffaceous siltstone and marl are found in some intrusions as xenoliths (Fig. 3). Large volumes of detritus originated from these intrusive domes, forming Pliocene- SED Pleistocene conglomerates (Fig. 3d), which indicate that the studied domes eventually 6, 2321–2370, 2014 outcropped at the Earth’s surface around the Miocene-Pliocene boundary (Salehine- 5 jad, 2008). Magma storage and plumbing of 3 Method adakite-type post-ophiolite 3.1 Analytical techniques intrusions Twenty-three fresh whole rock samples from the northern sector and 24 samples from K. Jamshidi et al. the southern sector were selected for major and trace element analysis at AMCE an- 10 alytical laboratory, Vancouver, Canada.
Load more

Recommended publications
  • Derivation of Intermediate to Silicic Magma from the Basalt Analyzed at the Vega 2 Landing Site, Venus
    RESEARCH ARTICLE Derivation of intermediate to silicic magma from the basalt analyzed at the Vega 2 landing site, Venus J. Gregory Shellnutt* National Taiwan Normal University, Department of Earth Sciences, Taipei, Taiwan * [email protected] Abstract a1111111111 a1111111111 Geochemical modeling using the basalt composition analyzed at the Vega 2 landing site a1111111111 indicates that intermediate to silicic liquids can be generated by fractional crystallization and a1111111111 equilibrium partial melting. Fractional crystallization modeling using variable pressures (0.01 a1111111111 GPa to 0.5 GPa) and relative oxidation states (FMQ 0 and FMQ -1) of either a wet (H2O = 0.5 wt%) or dry (H2O = 0 wt%) parental magma can yield silicic (SiO2 > 60 wt%) composi- tions that are similar to terrestrial ferroan rhyolite. Hydrous (H2O = 0.5 wt%) partial melting can yield intermediate (trachyandesite to andesite) to silicic (trachydacite) compositions at OPEN ACCESS all pressures but requires relatively high temperatures ( 950ÊC) to generate the initial melt Citation: Shellnutt JG (2018) Derivation of at intermediate to low pressure whereas at high pressure (0.5 GPa) the first melts will be intermediate to silicic magma from the basalt generated at much lower temperatures (< 800ÊC). Anhydrous partial melt modeling yielded analyzed at the Vega 2 landing site, Venus. PLoS mafic (basaltic andesite) and alkaline compositions (trachybasalt) but the temperature ONE 13(3): e0194155. https://doi.org/10.1371/ journal.pone.0194155 required to produce the first liquid is very high ( 1130ÊC). Consequently, anhydrous partial melting is an unlikely process to generate derivative liquids. The modeling results indicate Editor: Axel K Schmitt, Heidelberg University, GERMANY that, under certain conditions, the Vega 2 composition can generate silicic liquids that pro- duce granitic and rhyolitic rocks.
    [Show full text]
  • 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.
    [Show full text]
  • PAPERS Department of Geology
    PAPERS Department of Geology University of Queensland Volume 11 Number 4 PAPERS Department of Geology »University of Queensland VOLUME 11 NUMBER 4 The Tweed and Focal Peak Shield Volcanoes, Southeast Queensland and Northeast New South Wales . A. EWART, N.C. STEVENS and J.A. ROSS P. 1 - 82 1 THE TWEED AND FOCAL PEAK SHIELD VOLCANOES, SOUTHEAST QUEENSLAND AND NORTHEAST NEW SOUTH WALES by A. Ewart, N.C. Stevens and J.A, Ross ABSTRACT •Two overlapping shield volcanoes of Late Oligocène — Early Miocene age form mountainous country in southeast Queensland and northeast New South Wales. The basaltic-rhyolitic volcanic formations and the putonic rocks (gabbros, syenites, monzonites) of the central complexes are described with regard to field relations, mineralogy, geochem­ istry and petrogenesis. The Tweed Shield Volcano, centred on the plutonic complex of Mount Warning, comprises the Beechmont and Hobwee Basalts, their equivalents on the southern side (the Lismore and Blue Knob Basalts), and more localized rhyolite formations, the Binna Burra and Nimbin Rhyolites. The earlier Focal Peak Shield Volcano is preserved mainly on its eastern flanks, where the Albert Basalt and Mount Gillies Volcanics underlie the Beechmont Basalt. A widespread conglomerate formation separates formations of the two shield volcanoes. Mount Warning plutonic complex comprises various gabbros, syenite and monzonite with a syenite-trachyte-basalt ring-dyke, intrusive trachyandesite and comen­ dite dykes. The fine-grained granite of Mount Nullum and the basaltic sills of Mount Terragon are included with the complex. Each phase was fed by magma pulses from deeper chambers. Some degree of in situ crystal fractionation is shown by the gabbros, but the syenitic phase was already fractionated prior to emplacement.
    [Show full text]
  • Petrography Edward F
    Chapter 4 Petrography Edward F. Stoddard A petrographic study was taken in order to help determine the sources of lithic artifacts found at archaeological sites on Fort Bragg. In the first phase of the study, known and suspected archaeological quarry sites in the central Piedmont of North Carolina were visited. From each quarry, hand specimens were collected and petrographic thin sections were examined in an attempt to establish a basis for distinguishing among the quarries. If material from each quarry was sufficiently distinctive, then quarry sources could potentially be matched with Fort Bragg lithic artifacts. Seventy-one samples from 12 quarry zones were examined (Table 4.1). Thirty- one of these samples are from five quarry zones in the Uwharrie Mountains region; 20 of these were collected and described previously by Daniel and Butler (1996). Forty specimens were collected from seven additional quarry zones in Chatham, Durham, Person, Orange, and Cumberland Counties. All quarries are within the Carolina Terrane, except the Cumberland County quarry, which occurs in younger sedimentary material derived primarily from Carolina Terrane outcrops. Rocks include both metavolcanic and metasedimentary types. Compositionally, most metavolcanic rocks are dacitic and include flows, tuffs, breccias, and porphyries. Metasedimentary rocks are metamudstone and fine metasandstone. The Uwharrie quarries are divided into five zones: Eastern, Western, Southern, Asheboro, and Southeastern. The divisions are based primarily on macroscopic petrography and follow the results of Daniel and Butler (1996); the Uwharries Southeastern zone was added in this study. Each of the Uwharrie quarry zones represents three to six individual quarries in relatively close proximity. Rock specimens are all various felsic metavolcanic rocks, but zones may be distinguished based upon mineralogy and texture.
    [Show full text]
  • Wapiti" Formation and Trout Peak Trachyandesite Northwestern Wyoming
    Wapiti" Formation and Trout Peak Trachyandesite Northwestern Wyoming By WILLIS H. NELSON and WILLIAM G. PIERCE CONTRIBUTIONS TO STRATIGRAPHY GEOLOGICAL SURVEY BULLETIN 1254-H Description of two new formations in the Absaroka Mountains, If^yoming UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director U.S. GOVERNMENT PRINTING OFFICE WASHINGTON : 1968 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 10 cents (paper cover) CONTENTS Page Abstract--___-___-_-__--_-_--------------------------------------- HI Introduction _____-_______-____-____--_--_------------------------- 1 Wapiti Formation__________________----_---_--__------------------ 1 Trout Peak Trachyandesite___----_-----_--------------------------- 9 References cited._____________-_-_____-__--_----------------------- H ILLUSTRATIONS Page FIGUKE 1. Map showing generalized distribution of the Wapiti Forma­ tion and the Trout Peak Trachyandesite in the north­ eastern Absaroka Mountains, northwestern Wyoming_____- H2 2. Generalized stratigraphic sections______________---_--_---_ 4 TABLE Page TABLE 1. Chemical and normative analyses of rocks of the Wapiti For­ mation and the Trout Peak Trachyandesite-______________ H5 in CONTRIBUTIONS TO STRATIGRAPHY WAPITI FORMATION AND TROUT PEAK TRACHYANDESITE, NORTHWESTERN WYOMING By WILLIS H. NELSON and WILLIAM G. PIERCE ABSTRACT The volcanic rocks of the northeastern Absaroka Mountains consist of lava flows that are interbedded with breccia, sandstone, siltstone, and conglomerate composed, wholly or in part, of volcanic detritus. The name Wapiti Formation is given to the lower 1,500 to 4,000 feet of this heterogeneous assemblage, excluding the Cathedral Cliffs Formation, which locally underlies the Wapiti Formation in the northwestern part of the area.
    [Show full text]
  • Northwest Africa 11575: Unique Ungrouped Trachyandesite Achondrite
    49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083) 2226.pdf NORTHWEST AFRICA 11575: UNIQUE UNGROUPED TRACHYANDESITE ACHONDRITE. C. B. Agee, M. A. Habermann, K. Ziegler, Institute of Meteoritics, University of New Mexico, Albuquerque, NM 87131, [email protected]. Introduction: We report here the discovery of a mostly lath-like in shape, and typically 200x50 µm in unique achondritic meteorite, Northwest Africa size (fig. 1b). We also observed ubiquitous potassium (NWA) 11575, which has an estimated trachyandesite feldspar and a silica polymorph, which were common- bulk composition and oxygen isotopes plotting within ly found in contact with each other, and together make the LL-ordinary chondrite field. up ~5% of the modal mineralogy. Minor ubiquitous History and Physical Charateristics: NWA phases make up ~1% of the modal mineralogy; these 11575 was purchased by Darryl Pitt in Mauritania, include ilmenite, iron sulfide phase, iron metal (nickel 2016. The meteorite was reportedly found in June 2016 not detected with EMPA), chromite, phosphate phase, near the border region of Mali and Algeria. The speci- zircon, and iron oxide. men is a single stone, 598 grams, and is ~80% covered by fusion crust. A saw cut surface revealed a light col- 14 NWA 11575 Shock Melt Vein ored surface with an aphanitic texture. A single, ~1 mm wide, dark colored shock melt vein crosscuts this 12 surface. Also present are a few smaller xenoliths which ) 10 Trachyite % t Trachy- are dark in color, angular, and aphanitic; the largest of w ( andesite Rhyolite 8 O which is approximately 1 cm across (see [1] for images 2 Basaltic K trachy- + of the main mass and deposit sample).
    [Show full text]
  • Pleistocene Volcanism and Shifting Shorelines at Lake Tahoe, California GEOSPHERE, V
    Research Paper GEOSPHERE Pleistocene volcanism and shifting shorelines at Lake Tahoe, California GEOSPHERE, v. 14, no. 2 Winifred Kortemeier1, Andrew Calvert2, James G. Moore2, and Richard Schweickert3 1Western Nevada College, 2201 West College Parkway, Carson City, Nevada 89703, USA doi:10.1130/GES01551.1 2U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA 3Department of Geological Sciences and Engineering, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, USA 16 figures; 1 table; 1 supplemental file CORRESPONDENCE: [email protected] CITATION: Kortemeier, W., Calvert, A., Moore, J.G., ABSTRACT 1. INTRODUCTION and Schweickert, R., 2018, Pleistocene volcanism and shifting shorelines at Lake Tahoe, California: Geosphere, v. 14, no. 2, p. 812–834, doi:10.1130/ In the northwestern Lake Tahoe Basin, Pleistocene basaltic and trachy­ Basaltic and trachyandesitic lavas form a small Pleistocene volcanic field GES01551.1. andesitic lavas form a small volcanic field comprising ~1 km3 of lava that of ~1 km3 in the northwestern Lake Tahoe Basin (Fig. 1). Lavas and pyroclastic erupted from seven vents. Most of these lavas erupted subaerially and material erupted from approximately seven vents on both sides of the Truckee Science Editor: Raymond M. Russo produced lava flows. However, where they flowed into an early Lake Tahoe River, the lake outlet. In this study, a succession of basalt and trachyandesitic Associate Editor: Graham D.M. Andrews ( Proto­Tahoe), they produced deltas consisting of hydrovolcanic breccias as lavas was mapped, sampled, analyzed, and radiometrically dated to charac- Received 26 April 2017 well as pillow lavas draped downslope, pillow breccias, hyaloclastites, and terize the nature of the volcanism.
    [Show full text]
  • Lexicon of Stratigraphic Names Used in South-Central Colorado Amd Northern New Mexico, San Luis Basin Christina Lochman-Balk and James E
    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/22 Lexicon of stratigraphic names used in south-central Colorado amd northern New Mexico, San Luis Basin Christina Lochman-Balk and James E. Bruning, 1971, pp. 101-111 in: San Luis Basin (Colorado), James, H. L.; [ed.], New Mexico Geological Society 22nd Annual Fall Field Conference Guidebook, 340 p. This is one of many related papers that were included in the 1971 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. Copyright Information Publications of the New Mexico Geological Society, printed and electronic, are protected by the copyright laws of the United States.
    [Show full text]
  • Petrology of Sirdan Volcanic Rocks in Alborz Mountains, Northern Iran Revista Publicando, 5 No 16. (2). 2018, 63-88. ISSN 1390-9304
    Petrology of Sirdan volcanic rocks in Alborz Mountains, northern Iran Revista Publicando, 5 No 16. (2). 2018, 63-88. ISSN 1390-9304 Petrology of Sirdan volcanic rocks in Alborz Mountains, northern Iran Fatemeh Ghotb-Tahriri 1, Mohammad-Ali Arian 1*, Shahrooz Haghnazar 2, Mohsen Pourkermani 1 1- Department of geology, faculty of science, North Tehran Branch, Islamic Azad University, Tehran, Iran, [email protected], [email protected], mohsen.pourkermani@gmail .com 2- Department of geology, faculty of science, Lahijan Branch, Islamic Azad University, Lahijan, Iran, [email protected], ABSTRACT The study area is located around Sirdan town in Sofla-Tarum Mountains in Alborz, south west of Manjil City and west of Loshan, northern Iran. Talesh-Western Alborz volcanic belt was formed by the subduction of Neotethys ocean toward north. However, some researchers believe that the continental rift is responsible for its formation. Firstly, geological field trip was carried out and lithogeochemical samples were collected and prepared for chemical and mineralogical studies. Genetic pattern of the samples was also introduced based on the geochemical analysis and microscopic studies. Sirdan volcanic rocks (northern Iran) include pyroclastic and lava units. Lavas are basalt, andesite, trachyandesite, dacite and riolite. Pyroclastic rocks also consist of different kind of tuffs (lattice crystal tuff, halo lattice tuff, sandy tuff, clay tuff and tuffit), ignimbrite and breccia. Age of the formations belongs to tertiary (mostly Eocene to Oligocene). Basic lavas include olivine, clinopyroxene, plagioclase phenocrysts as well as opaque minerals and plagioclase and clinopyroxene microlite. The dominated texture of the samples is porphyritic microlite.
    [Show full text]
  • Volcanology and Petrogenesis of the Navajo Lake Volcanic Field
    UNLV Retrospective Theses & Dissertations 1-1-2006 Volcanology and petrogenesis of the Navajo Lake volcanic field Shara L Stowell University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/rtds Repository Citation Stowell, Shara L, "Volcanology and petrogenesis of the Navajo Lake volcanic field" (2006). UNLV Retrospective Theses & Dissertations. 1980. http://dx.doi.org/10.25669/6mt8-tvhq This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in UNLV Retrospective Theses & Dissertations by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. VOLCANOLOGY AND PETROGENESIS OF THE NAVAJO LAKE VOLCANIC FIELD by Shara L. Stowell Bachelor o f Science University o f Idaho, Moscow 2001 A thesis submitted in partial fulfillm ent o f the requirements for the Master of Science Degree in Geology Department of Geoscience College of Sciences Graduate College University of Nevada, Las Vegas May 2006 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: 1436793 Copyright 2006 by Stowell, Shara L. All rights reserved. INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted.
    [Show full text]
  • Geochemistry of Mantle-Related Intermediate Rocks from the Tibbit Hill Volcanic Suite, Quebec Appalachians
    Mineralogical Magazine, August 1998, Vol. 62(4), pp. 487-500 Geochemistry of mantle-related intermediate rocks from the Tibbit Hill volcanic suite, Quebec Appalachians ABDEL-FATTAHM. ABDEL-RAHMAN Department of Geology, American University of Beirut, Beirut, Lebanon AND V. STEPHEN KtrMAR~ELI Department of Geology, Concordia University, 7141 Sherbrooke Street West, Montreal, QC, Canada, H4B 1R6 ABSTRACT We present a study on major and trace element geochemistry of some intermediate lithologies from the predominantly basaltic Tibbit Hill volcanic suite in the Humber Zone of the Quebec Appalachians. The intermediate rocks probably formed as lava flows in the volcanic sequence. Their presence shows that this rift-related, c. 554 Ma volcanic sequence is not bimodal (basaltic-comenditic) as previously thought, but consists of a spectrum of compositions ranging from mafic through intermediate to felsic lithologies. The entire volcanic sequence is poly-deformed and generally metamorphosed to greenschist facies conditions. The intermediate rocks of the Tibbit Hill Formation are trachyandesitic, trachytic and comenditic in composition, and exhibit a wide range of SiO2 content (52 to 68 wt.%). Mg is highly depleted in most samples. Variations of silica versus the alkalis show that most of the samples are alkaline in nature. The rocks display a tholeiitic trend on a standard AFM diagram. In general, the examined rocks also exhibit a wide range of Sr (15 to 174 ppm), Rb (0 to 156 ppm), Zr (155 to 899 ppm), Nb (18 to 123 ppm), and Y (18 to 94 ppm). The concentration of Hf and Ta are generally low (6.6-14.8 ppm, and 3.3-6.6 ppm, respectively), compared to those of Zr and Nb.
    [Show full text]
  • Neogene-Quaternary Volcanic Forms in the Carpathian-Pannonian Region: a Review
    Cent. Eur. J. Geosci. • 2(3) • 2010 • 207-270 DOI: 10.2478/v10085-010-0024-5 Central European Journal of Geosciences Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review Review Article Jaroslav Lexa1∗, Ioan Seghedi2, Károly Németh3, Alexandru Szakács24, Vlastimil Koneˇcný5, Zoltán Pécskay6, Alexandrina Fülöp7, Marinel Kovacs7 1 Geological Institute of the Slovak Academy of Sciences, Bratislava, Slovakia, 2 Institute of Geodynamics, Romanian Academy, Bucharest, Romania 3 Volcanic Risk Solutions CS-INR, Massey University, Palmerston North, NewZealand, 4 Sapientia University, Dept. of Environmental Sciences, Cluj-Napoca, Romania 5 State Geological Institute of D. Štúr, Bratislava, Slovakia 6 Institute of Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary 7 North University, Faculty of Mineral Resources, Baia Mare, Romania Received 27 May 2010; accepted 18 July 2010 207 Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review Abstract: Neogene to Quaternary volcanic/magmatic activity in the Carpathian-Pannonian Region (CPR) occurred be- tween 21 and 0.1 Ma with a distinct migration in time from west to east. It shows a diverse compositional variation in response to a complex interplay of subduction with roll-back, back-arc extension, collision, slab break-off, delamination, strike-slip tectonics and microplate rotations, as well as in response to further evo- lution of magmas in the crustal environment by processes of differentiation, crustal contamination, anatexis and magma mixing. Since most of the primary volcanic forms have been affected by erosion, especially in areas of post-volcanic uplift, based on the level of erosion we distinguish: (1) areas eroded to the basement level, where paleovolcanic reconstruction is not possible; (2) deeply eroded volcanic forms with secondary morphology and possible paleovolcanic reconstruction; (3) eroded volcanic forms with remnants of original morphology preserved; and (4) the least eroded volcanic forms with original morphology quite well preserved.
    [Show full text]