DOCSLIB.ORG

Hydrothe~Mal Alteration of Basaltic Andesite and Other Rocks in Drill Hole Gs-6, Steamboat Springs, Nevada

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hydrothe~Mal Alteration of Basaltic Andesite and Other Rocks in Drill Hole Gs-6, Steamboat Springs, Nevada GEOLOGICAL SURVEY RESEARCH 1967 HYDROTHE~MAL ALTERATION OF BASALTIC ANDESITE AND OTHER ROCKS IN DRILL HOLE GS-6, STEAMBOAT SPRINGS, NEVADA By ROBERT SCHOEN and DONALD E. WHITE, Menlo Park, Calif. Abstract.-Geothermal waters produced two recognizable pat­ tionships between the compositions of waters and the terns of hydrothermal alteraltion in the rocks in drill hole observed alteration patterns. GS-6. During an early period, the rocks were subjected to The generalized geology of the thermal area is potassium metasomatism that formed K-feldspar and celadon­ ite from unstable feldspars and ferromagnesian minerals, re­ shown in figure 1. The basement rocks consist of a spectively. A later period of hydrogen metasomatism pro­ granodiorite pluton of late Mesozoic age intruded into duced mixed-layer· illite-montmorillonite, montmorillonite, and metamorphosed sedimentary and volcanic rocks of kaolinite, probably as a series directly related to the intensity probable early Mesozoic age. Tertiary and Quater­ of alteration. The clays formed during hydrogen metasoma­ nary volcanic and sedimentary rocks were deposited tism are irregularly distributed with depth and probably are related to reactions involving C02 and H2S. This later period intermittently on the evoded surf'ace of this basement, of argillization still may be in progress. and andesite dikes intruded the granodiorite. Out­ crops of the Tertiary volcanic and sedimentary rocks are too small to distinguish in figure 1, but core This paper presents the results of a mineralogic samples of these rocks, from drill hole GS-6, are shown study of GS-6, one of eight holes drilled at Steamboat in figure 2. Springs, Nev., by the U.S. Geological Survey for The oldest Ceno~oic rocks found in the thermal area geologic information. Steamboat Springs, located in are soda trachyte flows, tuff breccias, and assocjated the west-central part of Nevada, 10 miles south of sediments of the Alta Foormation of Oligocene ( ?) age. Reno, is an area of active hot springs (fig. 1). Eco­ These were followed by andesite flows, tuff breccias, nomic geologists have been interested in these springs and andesite dikes of the Kate Peak Formation of for about 100 years because minerals of antimony and Miocene ,or Pliocene age. The pre-Lousetown alluvium mercury, together with sman amounts of gold and consists of silt, sand, and gravel. Local patches of silver, precipitate from the hot waters. orthoquartzite, pediment gravels, and chalcedonic hot­ spring sinter are found associated with this alluvium. The Steamboat Springs thermal area straddles the The Steamboat basaltic andesite of the Lousetown boundary between the Mount Rose and Virginia City Formation was erupted in early Pleistocene time f.ol­ quadrangles. The regional geology of these quadran­ lowed immediately by domes of pumiceous rhyolite gles has been described recently by Thompson and of the Steamboat Hills Rhyolite. Pre-Lake Lahontan White (1964). White and others (1964) have pre­ alluvium is a;pproximately middle Pleistocene in age sented the detailed geology of the therm3ll area, in­ and· consists of fragments of older l'ocks, many of cluding an account of earlier studies and the 100'8 of which are cemented by hot-spring sinter. Post-Louse­ an drill holes, including GS-6. b The mineralogy of hydrothermally altered core from town clulIlcedonic sinter consists of sinter older than 4 of the U.S. Geological Survey drill holes has been deposits of Lake Lahontan and now mostly converted described by Sigvaldason and White (1961, 1962), and to chalcedony or cristobalite. Younger hot-spring Schoen and White (1965) similarly ITa ve described an sinter -deposits, consisting largely of uncrystallized additional 2 drill holes. In addition to presenting the opal, range up to the present in age. Both Post­ detailed mineralogy of core from drill hole GS-6, the Lousetown chalcedonic sinter :and the opaline hot­ present pwper compares the mineralogy of this drill spring deposits are combined under "Sinter" in fig­ hole with the others, and considers briefly the rela- ure 1. Date Pleistocene alluvium that is contempo- U.S. GEOL. SURVEY PROF. PAPER 575-B, PAGES Bll0-B119 BllO SCHOEN AND WHITE BIll N EXPLANATION LJ Sinter CJ Alluvium • Steamboat Springs 1 .thermal area 119°45' NEVADA Basaltic andesite ~ Mostly metamorphic and granitic rocks Contact Fault or fissure INDEX MAP $ GS-5 Drill hole or well cr­ Spring i'S- I( 4800 o 500 1000 1500 FEET L-____~ ____~ ______ I CONTOUR INTERVAL 100 FE~ET________________________________________ -J }<'IGURE l.--Generulizpd ~('ologi<; map of Steamuoat Springs thermal area, Washoe l'Ollllty, ::\ey. (;\lodified from detailed map, White aud other,;, I\)CH.) Bl12 MINERALOGY AND PETROLOGY ORIGINAL ROCK TYPE 2 - ----------- 6 - 0----------, ------- S? \ Z 00: \ OW \ w~ Z \ ...J-U «CI) \ I \ u \ \ Cristobalite \ Quartz \ 49 /0 (Including chalcedony) / / / / / / / // w ~ () :J / / <t: 68 1-. 0 _-~"Stibiconite u... >:J \ .,--- ~ ~ ...J ~ ...J \ CJ) « \ __ ---------- "\"1\ \" Cl \ ------- \ \ \" z \ \ \ \ \\ <t: -- -- -- ...J - w _-====.:::::===b-----....- Hydrothermal K-feldspar _--~? p 95 ~ U5 _-o---Celado~~o?o' .~ ~ 100 - w ----------;=-- 0 0 ...J --~~~~~===~--------- ~ Z \\, .___..=--==-=-==--=:.:::.-- '\ \ Cl. W « II) 111 - o~-_ K r't 0 u Igneous alkali feldspar '--:'-='"-':::::~==:::'--===='~--==-~-=:"'-=--:::.._ __ ao Inl e \ l- f: w ...J ,,---~~~~~~~~~~~~~~-- \ w « u... CI) " - --_:: - _ -:::..-~~-.-.Montmorillonite\ « ---~--~-~-- z 129 I- m , 'o~ ~Plagioclase -- -0:....- ~o~-o 133 1----,-----------------"/0)<;0.;0 Hydrothermal K-feldspar ~ __ ..-?)6 £ u~ / / ~--<Biotite ---- [o(\~ ...... -" ~ I I- -:J / ./ ~ -<"Ce\3 ~ ij' Q. (1)- / ,/,/,/ . //::>-,:""-,,\3':1 ~ I W 0> Cl ~:J ----- Present water table -----1- 0:...J -----,0/;:.:.'---------------------- -------::>-'~::;-:::~3':1~(-~- «...J /,z-7 // --~,,:"/-eo- ~'" Kaolinite I 155 « /,f? ~/'-- ",,\. , _---00-------- 0:..Q-:::::::-..:::-:::::. ___ ~_::::---_ ~ 0-- ----0, -----===_~oo 160 SODA TRA- -------- , ---::;::::::::- \ CHYTE ------ ',-------::::------ \ \3'J 171 ARKOSIC -'::;::::0 d 9a{ _00-- _0-- 0 ALLUVIUM Quartz _ -- -:\\ ~e\ S--.,~f~ed-\3'J~ ~ - I / __ -- aW':v....- -:;...--.... ""'" ""\~ ....- -- I Kaolinite / ~ 180 I- w 0- ouS 0- 0:::::::: o~ 0- 0 0 ''::: / \~{\e / --~-- --- \» t: / / ---:""-:....-::::-_ MOnt....... - -....... a.. 0: / ---:...-.:::::-_ mar·'.............. \ 190 I- 0 o 0 -0-0 ")-o/On· ....... o 0 Ci \ \ ,,~~ ~~Ec>" Ite" I 0 ,",of!.\. ,..'1,1.'- " I Z \ \ Plagioclase ~~\ Iy~~~; " « 0: \ \ " ~F~"Ot~~.0- " I 205 I- o /0 ___-::;:::..q"o "0'0$ Ec>,.o, 0, 0 ~ 0\ (!) I / __ /J I 210 cr=O"~- ~if1,.~if11 ~\-.o- o 25 50 75 100 APPROXIMATE PERCENTAGES OF PRINCIPAL MINERALS FIGURE 2.-Semiquantitative plot of mineralogy from drill hole GS-6. Dashed lines arbitrarily drawn straight between sample points. raneous with Lake Lahontan, and very small patches the stratigraphy can be found in the paper by White of Recent alluvium in the stream valleys, complete and others (1964). the depositional history of the area. All three aHu­ Drill hole GS-6 is collared at an altitude of 4,838 vial units, Pre-Lake Lahontan alluvium, alluvium feet in an extensive mass of relatively old silicious contemporaneous with Lake Lahontan, and Recent al­ sinter known as Sinter Hill (fig. 1). The depth of luvium, are combined under "Alluvium" in figure 1. the hole is 212 feet, and the depth to the water table During this time of extensive deposition in the is approximately 148 feet. Severrul months after drill­ Cenozoic, the Steamboat Springs thermal area was ing was completed, the water at the bottom of the ~l!lso undergoing episodes of deformation and periods drill hole had a temperature of 102.5°C, a pH of 6.7, of erosion. An account of the Cenozoic geologic his­ a rhloride content of only 12 parts per million, and tory of the area and a more detailed description of a specific conductance of 372 micromhos. This ex- SCHOEN AND WHITE Bl13 tremely dilute water is very different from the fluids dence from thin sections and chemical analyses, pro­ found in drill holes on the three thermally active vide miner'al percentages for each sample of drill core. terraces; typicalJy, the temperature there is about Chemical analyses of altered rocks and fresh rock 170°C, pH is about 6.2, chloride content is about 820 equivalents of the igneous rocks in GS-6 are pre­ ppm, and specific conductance is about 3,000 micro­ sented in truble 1. Additional chemical, normative, mhos. The dilute water of GS-6 is probably precipita­ and lTIiodal anrulyses for other rocks from the Steam­ tion that fell on the area, percolated underground, and boat Springs aTea are presented by White and others was heated moderately in the thermal environment. (1964, tables 1 and 2). Active construction of hot-spring sinter terraces is Good quantitative mineralogic control exists for the taking place today in the Steamboat Springs area at granodiorite that underlies most of the Steamboat lower altitudes where hot chloride water oontaining Springs thermal area, because of its relative homoge­ 300 ppm or more of Si02 discharges at the surface neity and the a vailability of chemically and petro­ (White and others, 1956). The sinter deposits of graphioally analyzed fresh samples. Therefore, the Sinter Hill prove that high-temperature, silica-bearing granodiorite samples in drill hole GS-6 were evalu­ waters discharged in the past at -altitudes at least 148 ated for semiquantitative mineralogy in the same man­ feet nbove the present water table.
Load more

Recommended publications
  • The Mineralogy and Chemistry of the Anorogenic Tertiary Silicic Volcanics
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 86, NO. Bll, PAGES 10242-10256, NOVEMBER 10, 1981 The Mineralogyand Chemistryof the AnorogenicTertiary SilicicVolcanics of S.E. Queenslandand N.E. New South Wales, Australia A. EWART Departmentof Geology& Mineralogy,University of Queensland,St. Lucia,Brisbane, Queensland 4067 The Late Oligocene-EarlyMiocene volcanismof this regionis chemicallystrongly bimodal; the mafic lavas(volmetrically dominant) comprise basalts, hawaiites, and tholeiiticandesites, while the silicic eruptivesare mainly comendites,potassic trachytes, and potassic,high-silica rhyolites.The comendites and rhyoliteshave distinctivetrace element abundancepatterns, notably the extreme depletionsof Sr, Ba, Mg, Mn, P, Cr, V, and Eu, and the variable em'ichraentof suchelements as Rb, Zr, Pb, Nb, Zn, U, and Th. The trachytesexhibit thesecharacteristics to lesserdegrees. The comenditesare distinguished from the rhyolitesby their overall relative enrichmentof the more highly chargedcations (e.g., LREE, Nb, Y, and especiallyZr) and Zn. The phenocrystmineralogy of the trachytesand rhyolitescomprises various combinationsof the following phases:sodic plagioclase(albite-andesine), calcic anorthoclase, sanidine, quartz, ferroaugite-ferrohedenbergite,ferrohypersthene, fayalitic olivine, ilmenite, titano- magnetite,and rarely biotite (near annite) and Fe-hastingsiticamphibole. Accessories include apatite, zircon, chevkinite (ferrohedenbergite-bearingrhyolites only), and allanite (amphibole and botite rhyo- lites only). The comenditesgenerally contain
    [Show full text]
  • Source to Surface Model of Monogenetic Volcanism: a Critical Review
    Downloaded from http://sp.lyellcollection.org/ by guest on September 28, 2021 Source to surface model of monogenetic volcanism: a critical review I. E. M. SMITH1 &K.NE´ METH2* 1School of Environment, University of Auckland, Auckland, New Zealand 2Volcanic Risk Solutions, Massey University, Palmerston North 4442, New Zealand *Correspondence: [email protected] Abstract: Small-scale volcanic systems are the most widespread type of volcanism on Earth and occur in all of the main tectonic settings. Most commonly, these systems erupt basaltic magmas within a wide compositional range from strongly silica undersaturated to saturated and oversatu- rated; less commonly, the spectrum includes more siliceous compositions. Small-scale volcanic systems are commonly monogenetic in the sense that they are represented at the Earth’s surface by fields of small volcanoes, each the product of a temporally restricted eruption of a composition- ally distinct batch of magma, and this is in contrast to polygenetic systems characterized by rela- tively large edifices built by multiple eruptions over longer periods of time involving magmas with diverse origins. Eruption styles of small-scale volcanoes range from pyroclastic to effusive, and are strongly controlled by the relative influence of the characteristics of the magmatic system and the surface environment. Gold Open Access: This article is published under the terms of the CC-BY 3.0 license. Small-scale basaltic magmatic systems characteris- hazards associated with eruptions, and this is tically occur at the Earth’s surface as fields of small particularly true where volcanic fields are in close monogenetic volcanoes. These volcanoes are the proximity to population centres.
    [Show full text]
  • Module 7 Igneous Rocks IGNEOUS ROCKS
    Module 7 Igneous Rocks IGNEOUS ROCKS ▪ Igneous Rocks form by crystallization of molten rock material IGNEOUS ROCKS ▪ Igneous Rocks form by crystallization of molten rock material ▪ Molten rock material below Earth’s surface is called magma ▪ Molten rock material erupted above Earth’s surface is called lava ▪ The name changes because the composition of the molten material changes as it is erupted due to escape of volatile gases Rocks Cycle Consolidation Crystallization Rock Forming Minerals 1200ºC Olivine High Ca-rich Pyroxene Ca-Na-rich Amphibole Intermediate Na-Ca-rich Continuous branch Continuous Discontinuous branch Discontinuous Biotite Na-rich Plagioclase feldspar of liquid increases liquid of 2 Temperature decreases Temperature SiO Low K-feldspar Muscovite Quartz 700ºC BOWEN’S REACTION SERIES Rock Forming Minerals Olivine Ca-rich Pyroxene Ca-Na-rich Amphibole Na-Ca-rich Continuous branch Continuous Discontinuous branch Discontinuous Biotite Na-rich Plagioclase feldspar K-feldspar Muscovite Quartz BOWEN’S REACTION SERIES Rock Forming Minerals High Temperature Mineral Suite Olivine • Isolated Tetrahedra Structure • Iron, magnesium, silicon, oxygen • Bowen’s Discontinuous Series Augite • Single Chain Structure (Pyroxene) • Iron, magnesium, calcium, silicon, aluminium, oxygen • Bowen’s Discontinuos Series Calcium Feldspar • Framework Silicate Structure (Plagioclase) • Calcium, silicon, aluminium, oxygen • Bowen’s Continuous Series Rock Forming Minerals Intermediate Temperature Mineral Suite Hornblende • Double Chain Structure (Amphibole)
    [Show full text]
  • Geological Mapping, Structural Setting and Petrographic Description of the Archean Volcanic Rocks of Mnanka Area, North Mara
    PROCEEDINGS, 43rd Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, February 12-14, 2018 SGP-TR-213 Geological Mapping, Structural Setting and Petrographic Description of the Archean Volcanic Rocks of Mnanka Area, North Mara Ezra Kavana Acacia Mining PLc, North Mara Gold Mine, Department of Geology, P. O. Box 75864, Dar es Salaam, Tanzania Email: [email protected] Keywords: Musoma Mara Greenstone Belt, Mnanka volcanics, Archaean rocks and lithology ABSTRACT The Mnanka area is situated within the Musoma Mara Greenstone Belt, the area is near to Nyabigena, Gokona and Nyabirama gold mines. Mnanka area comprises of the sequence of predominant rhyolitic volcanic rocks, chert and metasediments. Gold mineralizations in Mnanka area is structure controlled and occur mainly as hydrothermal disseminated intrusion related deposits. Hence the predominant observed structures are joints and flow banding. Measurements from flow banding plotted on stereonets using win-TENSOR software has provided an estimate for the general strike of the area lying 070° to 100° dipping at an average range angle of 70° to 85° while data from joints plotted on stereonets suggest multiple deformation events one of which conforms to the East Africa Rift System (striking WSW-ENE, NNE-SSW and N-S). 1. INTRODUCTION This paper focuses on performing a systematic geological mapping and description of structures and rocks of the Mnanka area. The Mnanka area is located in the Mara region, Tarime district within the Musoma Mara Greenstone Belt. The gold at Mnanka is host ed by volcanic rocks that belong to the Musoma Mara Greenstone Belt (Figure 1). The Mnanka volcanics are found within the Kemambo group that comprises of the sequence of predominant rhyolitic volcanic rocks, chert and metasediments south of the Nyarwana fault.
    [Show full text]
  • Chemical and Isotopic Studies of Monogenetic Volcanic Fields: Implications for Petrogenesis and Mantle Source Heterogeneity
    MIAMI UNIVERSITY The Graduate School Certificate for Approving the Dissertation We hereby approve the Dissertation of Christine Rasoazanamparany Candidate for the Degree DOCTOR OF PHILOSOPHY ______________________________________ Elisabeth Widom, Director ______________________________________ William K. Hart, Reader ______________________________________ Mike R. Brudzinski, Reader ______________________________________ Marie-Noelle Guilbaud, Reader ______________________________________ Hong Wang, Graduate School Representative ABSTRACT CHEMICAL AND ISOTOPIC STUDIES OF MONOGENETIC VOLCANIC FIELDS: IMPLICATIONS FOR PETROGENESIS AND MANTLE SOURCE HETEROGENEITY by Christine Rasoazanamparany The primary goal of this dissertation was to investigate the petrogenetic processes operating in young, monogenetic volcanic systems in diverse tectonic settings, through detailed field studies, elemental analysis, and Sr-Nd-Pb-Hf-Os-O isotopic compositions. The targeted study areas include the Lunar Crater Volcanic Field, Nevada, an area of relatively recent volcanism within the Basin and Range province; and the Michoacán and Sierra Chichinautzin Volcanic Fields in the Trans-Mexican Volcanic Belt, which are linked to modern subduction. In these studies, key questions include (1) the role of crustal assimilation vs. mantle source enrichment in producing chemical and isotopic heterogeneity in the eruptive products, (2) the origin of the mantle heterogeneity, and (3) the cause of spatial-temporal variability in the sources of magmatism. In all three studies it was shown that there is significant compositional variability within individual volcanoes and/or across the volcanic field that cannot be attributed to assimilation of crust during magmatic differentiation, but instead is attributed to mantle source heterogeneity. In the first study, which focused on the Lunar Crater Volcanic Field, it was further shown that the mantle heterogeneity is formed by ancient crustal recycling plus contribution from hydrous fluid related to subsequent subduction.
    [Show full text]
  • Relationships Between Pre-Eruptive Conditions and Eruptive Styles of Phonolite-Trachyte Magmas Joan Andújar, Bruno Scaillet
    Relationships between pre-eruptive conditions and eruptive styles of phonolite-trachyte magmas Joan Andújar, Bruno Scaillet To cite this version: Joan Andújar, Bruno Scaillet. Relationships between pre-eruptive conditions and eruptive styles of phonolite-trachyte magmas. Lithos, Elsevier, 2012, 152 (1), pp.122-131. 10.1016/j.lithos.2012.05.009. insu-00705854 HAL Id: insu-00705854 https://hal-insu.archives-ouvertes.fr/insu-00705854 Submitted on 10 Jul 2012 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. 1 Relationships between pre-eruptive conditions and eruptive styles of phonolite-trachyte magmas JOAN ANDÚJAR*,a AND BRUNO SCAILLETa a. CNRS/INSU-UNIVERSITÉ D’ORLÉANS-BRGM ; INSTITUT DES SCIENCES DE LA TERRE D’ORLEANS, UMR 6113 - 1A, RUE DE LA FÉRROLLERIE-45071 ORLEANS CEDEX 2 (FRANCE) * Corresponding author : Joan Andújar phone number : (+33) 2 38 25 53 87 Fax: (+33) 02 38 63 64 88 e-mail address: [email protected] Bruno Scaillet e-mail address: [email protected] KEY WORDS: Phase equilibria, phonolite, trachyte, experimental petrology, eruptive dynamic, explosive, effusive, andesite, rhyolite, melt viscosity, magma viscosity. 2 Abstract Phonolitic eruptions can erupt either effusively or explosively, and in some cases develop highly energetic events such as caldera-forming eruptions.
    [Show full text]
  • Part 629 – Glossary of Landform and Geologic Terms
    Title 430 – National Soil Survey Handbook Part 629 – Glossary of Landform and Geologic Terms Subpart A – General Information 629.0 Definition and Purpose This glossary provides the NCSS soil survey program, soil scientists, and natural resource specialists with landform, geologic, and related terms and their definitions to— (1) Improve soil landscape description with a standard, single source landform and geologic glossary. (2) Enhance geomorphic content and clarity of soil map unit descriptions by use of accurate, defined terms. (3) Establish consistent geomorphic term usage in soil science and the National Cooperative Soil Survey (NCSS). (4) Provide standard geomorphic definitions for databases and soil survey technical publications. (5) Train soil scientists and related professionals in soils as landscape and geomorphic entities. 629.1 Responsibilities This glossary serves as the official NCSS reference for landform, geologic, and related terms. The staff of the National Soil Survey Center, located in Lincoln, NE, is responsible for maintaining and updating this glossary. Soil Science Division staff and NCSS participants are encouraged to propose additions and changes to the glossary for use in pedon descriptions, soil map unit descriptions, and soil survey publications. The Glossary of Geology (GG, 2005) serves as a major source for many glossary terms. The American Geologic Institute (AGI) granted the USDA Natural Resources Conservation Service (formerly the Soil Conservation Service) permission (in letters dated September 11, 1985, and September 22, 1993) to use existing definitions. Sources of, and modifications to, original definitions are explained immediately below. 629.2 Definitions A. Reference Codes Sources from which definitions were taken, whole or in part, are identified by a code (e.g., GG) following each definition.
    [Show full text]
  • Rhyolite and Trachyte Formation at Lake City Caldera: Insight from Quantitative Textural and Geochemical Analyses
    Michigan Technological University Digital Commons @ Michigan Tech Dissertations, Master's Theses and Master's Reports 2016 Rhyolite and Trachyte Formation at Lake City Caldera: Insight from Quantitative Textural and Geochemical Analyses Jordan Lubbers Michigan Technological University, [email protected] Copyright 2016 Jordan Lubbers Recommended Citation Lubbers, Jordan, "Rhyolite and Trachyte Formation at Lake City Caldera: Insight from Quantitative Textural and Geochemical Analyses", Open Access Master's Thesis, Michigan Technological University, 2016. https://doi.org/10.37099/mtu.dc.etdr/99 Follow this and additional works at: https://digitalcommons.mtu.edu/etdr Part of the Geochemistry Commons, and the Geology Commons RHYOLITE AND TRACHYTE FORMATION AT LAKE CITY CALDERA: INSIGHT FROM QUANTITATIVE TEXTURAL AND GEOCHEMICAL ANALYSES By Jordan E. Lubbers A THESIS Submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE In Geology MICHIGAN TECHNOLOGICAL UNIVERSITY 2016 © 2016 Jordan E. Lubbers This thesis has been approved in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE in Geology. Geological and Mining Engineering and Sciences ThesisDepartment Advisor: ofChad Deering Committee Member: Olivier Bachmann Committee Member: William Rose Department Chair: John Gierke Table of Contents Acknowledgements ................................................................................................................................................. 6 Abstract ......................................................................................................................................................................
    [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]
  • The Boring Volcanic Field of the Portland-Vancouver Area, Oregon and Washington: Tectonically Anomalous Forearc Volcanism in an Urban Setting
    Downloaded from fieldguides.gsapubs.org on April 29, 2010 The Geological Society of America Field Guide 15 2009 The Boring Volcanic Field of the Portland-Vancouver area, Oregon and Washington: Tectonically anomalous forearc volcanism in an urban setting Russell C. Evarts U.S. Geological Survey, 345 Middlefi eld Road, Menlo Park, California 94025, USA Richard M. Conrey GeoAnalytical Laboratory, School of Earth and Environmental Sciences, Washington State University, Pullman, Washington 99164, USA Robert J. Fleck Jonathan T. Hagstrum U.S. Geological Survey, 345 Middlefi eld Road, Menlo Park, California 94025, USA ABSTRACT More than 80 small volcanoes are scattered throughout the Portland-Vancouver metropolitan area of northwestern Oregon and southwestern Washington. These vol- canoes constitute the Boring Volcanic Field, which is centered in the Neogene Port- land Basin and merges to the east with coeval volcanic centers of the High Cascade volcanic arc. Although the character of volcanic activity is typical of many mono- genetic volcanic fi elds, its tectonic setting is not, being located in the forearc of the Cascadia subduction system well trenchward of the volcanic-arc axis. The history and petrology of this anomalous volcanic fi eld have been elucidated by a comprehensive program of geologic mapping, geochemistry, 40Ar/39Ar geochronology, and paleomag- netic studies. Volcanism began at 2.6 Ma with eruption of low-K tholeiite and related lavas in the southern part of the Portland Basin. At 1.6 Ma, following a hiatus of ~0.8 m.y., similar lavas erupted a few kilometers to the north, after which volcanism became widely dispersed, compositionally variable, and more or less continuous, with an average recurrence interval of 15,000 yr.
    [Show full text]
  • 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 .
    [Show full text]
  • The Volcano-Tectonic Evolution of the Miocene Santa Lucía Volcano, Boaco District, Nicaragua
    Journal of Geosciences, 56 (2011), 27–41 DOI: 10.3190/jgeosci.085 Original paper The volcano-tectonic evolution of the Miocene Santa Lucía Volcano, Boaco district, Nicaragua David BURIÁNEK1*, Petr HRADECKÝ2 1 Czech Geological Survey, Leitnerova 22, 658 59 Brno, Czech Republic; [email protected] 2 Czech Geological Survey, Klárov 3, 118 21 Prague 1, Czech Republic; [email protected] * Corresponding author The present-day Santa Lucía caldera is an erosional relic of a Late Oligocene to Early Miocene stratoshield volcano located in the south-western part of the Chortis Block in Central Nicaragua. Six main lithological units were recogni- zed: (Unit I) dacitic ignimbrite of Boaco type, which represents the basement of the Santa Lucía caldera; (Unit II) da- citic ignimbrite of Fonseca type, locally intercalated with epiclastic and dacitic lavas; (Unit III) “lower” andesite lavas; (Unit IV) blocky, lithic-rich pyroclastic flow deposits, (Unit V) “upper” andesite and basalt lavas, and (Unit VI) epic- lastic rocks (lahar deposits). On the basis of field mapping, petrological and geochemical data, a new model for the evolution of the Santa Lucía Vol- cano is presented. The first stage consisted of a series of strong Sub-Plinian eruptions, which produced thick ignimbri- te units. These events destroyed the pre-existing volcanic edifice. The second stage was dominated by large explosive eruptions producing mainly non-welded dacitic–andesitic ignimbrites. The next resulted in the formation of andesitic lava flows and minor tephra fall-out deposits, covered by voluminous basaltic lavas. Lahars probably triggered by vol- canic and/or seismic events represent the final stage of volcanic activity.
    [Show full text]