DOCSLIB.ORG

The Geology and Genesis of Jasperoid in the Northern Swisshelm Mountains, Cochise County, Arizona

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Geology and Genesis of Jasperoid in the Northern Swisshelm Mountains, Cochise County, Arizona The geology and genesis of jasperoid in the northern Swisshelm Mountains, Cochise County, Arizona Item Type text; Thesis-Reproduction (electronic); Maps Authors McAlaster, Penelope Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 27/09/2021 13:51:00 Link to Item http://hdl.handle.net/10150/557559 THE GEOLOGY AND GENESIS OF JASPEROID IN THE NORTHERN SWISSHELM MOUNTAINS, COCHISE COUNTY, ARIZONA by Penelope McAlaster A Thesis Submitted to the Faculty of the DEPARTMENT OF GEOSCIENCES In Partial Fulfillment of the Requirements For the Degree of MASTER OF SCIENCE In the Graduate College THE UNIVERSITY OF ARIZONA 1 9 8 0- STATEMENT BY AUTHOR This thesis has been submitted in partial fulfillment of re­ quirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his judg­ ment the proposed use of the material is in the interests of scholar­ ship. In all other instances, however, permission must be obtained from the author. V SIGNED; ( ") <? s t> ■ / " APPROVAL BY THESIS DIRECTOR This thesis has been approved on the date shown below: ^^0 $> I9<P0 J. MZ (tUILBERT Date Professor ofi Geosciences ACKNOWLEDGMENTS For its financial funding and access to its Swisshelm data and drill core, I thank the Inspiration Development Company. Drill core and drill logs were also made available to me by D. Huckins of Tucson. X-ray, fluid inclusion, and electron microprobe studies were done on equipment provided by the Departments of Geosciences and Space Sciences at The University of Arizona. My thanks to Dr. Guilbert for suggesting this interesting area for my study. iii TABLE OF CONTENTS Page LIST OF ILLUSTRATIONS............................................ vi ABSTRACT ........................................................ viii INTRODUCTION .................................................... 1 Problem . fH rH CM CO Jasperoid Method of Treatment Previous Work . Location ........ GENERAL GEOLOGY OF THE NORTHERN SWISSHELM MOUNTAINS ............ 7 Stratigraphy and Lithology ................................. 7 Precambrian Rocks .... ............................... 7 Cambrian-Ordovician Rocks .... ....................... 7 Devonian Rocks .......................................... 9 Mississippian Rocks ..................................... 10 P ennsyIvanian-P eraian Rocks .............................. 11 Late Cretaceous-Early Tertiary Rocks ................... 13 Tertiary Rocks .......................................... 14 Structure.................................................... 15 F o l d s .................................................... 15 F a u l t s .................................................. 16 Fractures................................................ 16 RELATIONSHIP OF JASPEROID TO MINERAL DEPOSITS ................... 19 DISTRIBUTION AND CONTROLS OF JASPEROID ......................... 22 Stratigraphic Occurrences ................................... 22 Structural Occurrences ..................................... 24 PHYSICAL PROPERTIES OF NORTHERN SWISSHEIM MOUNTAINS JASPEROID . 28 Megascopic Properties ..................... 28 C o l o r .................................................... 28 T e x t u r e s ................................................ 29 M i n e r a l o g y .............................................. 31 Petrographic Features .... ............................... 33 Microcrystalline Quartz Textures ....................... 33 iv V TABLE OF CONTENTS— Continued Page Coarse Quartz Textures ................................. 42 Associated Minerals ..................................... 42 Jasperoid-limestone Contact ................................. 42 CHEMICAL COMPOSITION OF THE JASPEROID ................... .... 52 FLUID INCLUSION D A T A ............................................ 53 ALUMINUM IN QUARTZ AS A GEOTH E R M O M E T E R ................... 56 GENESIS OF JASPEROID IN THE NORTHERN SWISSHELM MOUNTAINS .... 60 Solubility of S i l i c a ...................... 60 Deposition of Silica ........................................ 63 Chemical Mechanisms of Limestone Replacement ............... 63 Origin of Jasperoid Textures ............................... 64 Origin of S i l i c a ............................................ 67 CONCLUSIONS...................................................... 71 LIST OF R E F E R E N C E S .............................................. 73 LIST OF ILLUSTRATIONS Figure Page 1. Cochise County M a p ....................................... 5 2. Location Map of Northern Swisshelm Mountains ............ 6 3. Geology of the Northern Swisshelm Mountains .......... in pocket 4. Stereonet Projection of Poles to Fracture Planes in the Northern Swisshelm Mountains ......................... 18 5. Prominent Outcrops of Jasperoid .......... 23 6. Silicified Tuff . ....................... 25 7. Jasperoid Cropping Out along a Fault ..................... 26 8. Non-ideal Ribbon Rock in the Northern Swisshelm Jasperoid ............................................ 30 9. Jasperoid Breccia Cemented by Second Generation Microcrystalline Quartz ............................. 32 10. ’Jigsaw-puzzle' and Xenomorphic Textures ................. 34 11. Xenomorphic Granular Quartz-filling Vug ................. 36 12. Reticulated Texture ..................................... 37 13. Photomicrograph of Jasperoid Breccia Cemented by Second Generation of Microcrystalline Quartz .............. 39 14. Fusilinid in Plane-polarized Light . ................ 40 15. F u s i l i n i d ................................................ 41 16. Jasperoid-limestone Contact in Outcrop ................... 43 17. Typical Sharp Contact of Reddish-brown Jasperoid and . Bluish-grey Limestone ............................... 44 18. Typical Jasperoid-limestone Contact on Slabbed Surface . 45 19. Acid Leach S t u d y .......................................... 47 vi vii LIST OF ILLUSTRATIONS— Continued Figure Page 20. Gradational Limestone-silica Contact in Thin Section . 49 21. Limestone-silica Contact Associated with Fractures in Thin S e c t i o n ..................................... 50 22. Homogenization Temperatures of Primary Inclusions in Coarse-grained Quartz from Vugs and Ribbon Rock from Sections 26, 35, 1 and 12 .... ............... 55 23. Step Scan for "Aluminum across Fine- and Coarse-grained Q u a r t z ................................................ 57 24. Measured Relation of Temperature and Aluminum Solubility for Natural and Synthetic Quartz ...................... 59 25. Solubilities of CaCOg and Si02 in Pure Water at One Atmosphere CO2 and Vapor Pressure of Solution, Respectively . ........................... 61 ABSTRACT The Swisshelm mining district is situated in the northern Swiss- helm Mountains, Cochise County, Arizona. The range is an eastward-tilted fault block complex consisting of a Precambrian basement overlain by Pa­ leozoic sedimentary rocks. Laramide(?) and Tertiary intrusive and extru­ sive rocks are also present. The range is cut by both eastward-dipping thrust faults and high- and low-angle normal faults. Silicic replacement bodies, or jasperoids, related to Tertiary volcanism rather than the mineralized dikes, crop out conspicuously north of the mining activity. The distribution of jasperoid is controlled both by faults and by favorable limestone beds. Studies of the jasperoid suggest that it is limestone replaced by silica gel which then crystallized to microcrystalline quartz. Coarse­ grained quartz precipitated directly from solutions in open spaces. Flu­ id inclusion study suggests homogenization temperatures of coarse-grained quartz from 145 to 216°C. Microprobe analyses of aluminum in varieties of quartz suggest that microcrystalline quartz formed at temperatures higher than 216°C. Geochemical analyses show that the jasperoid is near­ ly pure Si02« Decreasing temperature and increasing P^Q^ solutions carrying silica encouraged replacement of limestone by flow through per­ meable fault zones and by diffusion. viii INTRODUCTION The northern Swisshelm mining district consists of several small mines including the Chance, Mountain Queen, March, Great American, and Mammoth which have produced a total of approximately 61,000 tons of pre­ dominantly lead-zinc-silver ore (Keith, 1973). The mineralization is thought to be associated with a local Laramide(?) andesitic intrusion. Jasperoid of previously unknown origin and age is abundant in the lime­ stones of Paleozoic age near and in a projactable band for several kilom­ eters north of the lead-zinc-silver mineralization. Problem This study investigates the stratigraphic and structural rela­ tionships of jasperoid in the area. The jasperoid had not been mapped in detail in published works, but it was noted on several maps of the northern Swisshelm Mountains prepared by Beaver Exploration and by Inspi­ ration Development
Load more

Recommended publications
  • Chiricahua Leopard Frog (Rana Chiricahuensis)
    U.S. Fish & Wildlife Service Chiricahua Leopard Frog (Rana chiricahuensis) Final Recovery Plan April 2007 CHIRICAHUA LEOPARD FROG (Rana chiricahuensis) RECOVERY PLAN Southwest Region U.S. Fish and Wildlife Service Albuquerque, New Mexico DISCLAIMER Recovery plans delineate reasonable actions that are believed to be required to recover and/or protect listed species. Plans are published by the U.S. Fish and Wildlife Service, and are sometimes prepared with the assistance of recovery teams, contractors, state agencies, and others. Objectives will be attained and any necessary funds made available subject to budgetary and other constraints affecting the parties involved, as well as the need to address other priorities. Recovery plans do not necessarily represent the views nor the official positions or approval of any individuals or agencies involved in the plan formulation, other than the U.S. Fish and Wildlife Service. They represent the official position of the U.S. Fish and Wildlife Service only after they have been signed by the Regional Director, or Director, as approved. Approved recovery plans are subject to modification as dictated by new findings, changes in species status, and the completion of recovery tasks. Literature citation of this document should read as follows: U.S. Fish and Wildlife Service. 2007. Chiricahua Leopard Frog (Rana chiricahuensis) Recovery Plan. U.S. Fish and Wildlife Service, Southwest Region, Albuquerque, NM. 149 pp. + Appendices A-M. Additional copies may be obtained from: U.S. Fish and Wildlife Service U.S. Fish and Wildlife Service Arizona Ecological Services Field Office Southwest Region 2321 West Royal Palm Road, Suite 103 500 Gold Avenue, S.W.
    [Show full text]
  • Alkalic-Type Epithermal Gold Deposit Model
    Alkalic-Type Epithermal Gold Deposit Model Chapter R of Mineral Deposit Models for Resource Assessment Scientific Investigations Report 2010–5070–R U.S. Department of the Interior U.S. Geological Survey Cover. Photographs of alkalic-type epithermal gold deposits and ores. Upper left: Cripple Creek, Colorado—One of the largest alkalic-type epithermal gold deposits in the world showing the Cresson open pit looking southwest. Note the green funnel-shaped area along the pit wall is lamprophyre of the Cresson Pipe, a common alkaline rock type in these deposits. The Cresson Pipe was mined by historic underground methods and produced some of the richest ores in the district. The holes that are visible along several benches in the pit (bottom portion of photograph) are historic underground mine levels. (Photograph by Karen Kelley, USGS, April, 2002). Upper right: High-grade gold ore from the Porgera deposit in Papua New Guinea showing native gold intergrown with gold-silver telluride minerals (silvery) and pyrite. (Photograph by Jeremy Richards, University of Alberta, Canada, 2013, used with permission). Lower left: Mayflower Mine, Montana—High-grade hessite, petzite, benleonardite, and coloradoite in limestone. (Photograph by Paul Spry, Iowa State University, 1995, used with permission). Lower right: View of north rim of Navilawa Caldera, which hosts the Banana Creek prospect, Fiji, from the portal of the Tuvatu prospect. (Photograph by Paul Spry, Iowa State University, 2007, used with permission). Alkalic-Type Epithermal Gold Deposit Model By Karen D. Kelley, Paul G. Spry, Virginia T. McLemore, David L. Fey, and Eric D. Anderson Chapter R of Mineral Deposit Models for Resource Assessment Scientific Investigations Report 2010–5070–R U.S.
    [Show full text]
  • Major Geologic Structures Between Lordsburg, New Mexico, and Tucson, Arizona Harald D
    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/29 Major geologic structures between Lordsburg, New Mexico, and Tucson, Arizona Harald D. Drewes and C. H. Thorman, 1978, pp. 291-295 in: Land of Cochise (Southeastern Arizona), Callender, J. F.; Wilt, J.; Clemons, R. E.; James, H. L.; [eds.], New Mexico Geological Society 29th Annual Fall Field Conference Guidebook, 348 p. This is one of many related papers that were included in the 1978 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]
  • Carlin-Type Gold Deposits in Nevada: Critical Geologic Characteristics and Viable Models
    ©2005 Society of Economic Geologists, Inc. Economic Geology 100th Anniversary Volume pp. 451–484 Carlin-Type Gold Deposits in Nevada: Critical Geologic Characteristics and Viable Models JEAN S. CLINE,† University of Nevada, Las Vegas, 4505 Maryland Parkway, Box 454010, Las Vegas, Nevada 89154-4010 ALBERT H. HOFSTRA, Mineral Resources Program, U.S. Geological Survey, Mail Stop 973, Box 25046, Denver, Colorado 80225 JOHN L. MUNTEAN, Nevada Bureau of Mines and Geology, Mail Stop 178, University of Nevada, Reno, Nevada 89557-0088 RICHARD M. TOSDAL, AND KENNETH A. HICKEY Mineral Deposit Research Unit, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia, Canada V6T 1Z4 Abstract Carlin-type Au deposits in Nevada have huge Au endowments that have made the state, and the United States, one of the leading Au producers in the world. Forty years of mining and numerous studies have pro- vided a detailed geologic picture of the deposits, yet a comprehensive and widely accepted genetic model re- mains elusive. The genesis of the deposits has been difficult to determine owing to difficulties in identifying and analyzing the fine-grained, volumetrically minor, and common ore and gangue minerals, and because of postore weathering and oxidation. In addition, other approximately contemporaneous precious metal deposits have overprinted, or are overprinted by, Carlin-type mineralization. Recent geochronological studies have led to a consensus that the Nevada deposits formed ~42 to 36 m.y. ago, and the deposits can now be evaluated in the context of their tectonic setting. Continental rifting and deposi- tion of a passive margin sequence followed by compressional orogenies established a premineral architecture of steeply dipping fluid conduits, shallow, low dipping “traps” and reactive calcareous host rocks.
    [Show full text]
  • You Can Learn More About the Chiricahuas
    Douglas RANGER DISTRICT www.skyislandaction.org 2-1 State of the Coronado Forest DRAFT 11.05.08 DRAFT 11.05.08 State of the Coronado Forest 2-2 www.skyislandaction.org CHAPTER 2 Chiricahua Ecosystem Management Area The Chiricahua Mountain Range, located in the Natural History southeastern corner of the Coronado National Forest, The Chiricahua Mountains are known for their is one of the largest Sky Islands in the U.S. portion of amazing variety of terrestrial plants, animals, and the Sky Island region. The range is approximately 40 invertebrates. They contain exceptional examples of miles long by 20 miles wide with elevations ranging ecosystems that are rare in southern Arizona. While from 4,400 to 9,759 feet at the summit of Chiricahua the range covers only 0.5% of the total land area in Peak. The Chiricahua Ecosystem Management Area Arizona, it contains 30% of plant species found in (EMA) is the largest Management Area on the Forest Arizona, and almost 50% of all bird species that encompassing 291,492 acres of the Chiricahua and regularly occur in the United States.1 The Chiricahuas Pedragosa Mountains. form part of a chain of mountains spanning from Protected by remoteness, the Chiricahuas remain central Mexico into southern Arizona. Because of one of the less visited ranges on the Coronado their proximity to the Sierra Madre, they support a National Forest. Formerly surrounded only by great diversity of wildlife found nowhere else in the ranches, the effects of Arizona’s explosive 21st century United States such as the Mexican Chickadee, whose population growth are beginning to reach the flanks only known breeding locations in the country are in of the Chiricahuas.
    [Show full text]
  • Session 5 Epigenetic Gold Systems
    Session 5 Epigenetic gold systems Chapter 5-1 5-1 Geochemical and isotopic constraints on Palaeozoic orogenic gold endowment and crustal evolution of the south central Andes, NW Argentina Frank P. Bierlein School of Geoscience, Monash University, Melbourne, VIC 3800, Australia, and Tectonics Special Research Centre, The Uni- versity of Western Australia, Crawley, WA 6009, Australia Beatriz Coira CONICET and Instituto de Geología y Minería, Universidad Nacional de Jujuy, 4600 San Salvador de Jujuy, Argentina Holly Stein AIRIE Program, Department of Earth Resources, Colorado State University, Fort Collins, CO 80523-1482 USA Abstract. Major and trace element concentrations, and Nd isotope spreading ridges and/or mantle plumes, play important compositions of Ordovician volcano-intrusive rocks in the Puna of roles in the ore-forming process (Bierlein and Crowe 2000). northwestern Argentina point to their formation in a pericratonic Thus, it can be hypothesised that variations in the vol- setting above thickened and evolved continental crust. Input from juvenile sources was limited and there is no evidence for oceanic ume and composition of mafic rocks underlying a meta- crust or the presence of a terrane-bounding suture in the region. In sedimentary succession represent key elements in the eco- contrast to analogous terrains elsewhere in the Central Andes (e.g., nomic evaluation of a given fold belt. in Peru and Bolivia), relatively minor orogenic gold mineralisation In this study, we report results of petrogenetic and iso- is known to occur in the Palaeozoic succession in northwestern Ar- topic investigations aimed at characterising and finger- gentina. Possible explanations for the lack of more substantial oro- genic gold endowment include the absence of hydrated oceanic printing mafic intrusives, related volcanic rocks, and substrate in the Puna, lack of 1st-order conduits and the limited ex- metasedimentary rocks in the Puna Argentina.
    [Show full text]
  • Metallogeny of Northern, Central and Eastern Asia
    METALLOGENY OF NORTHERN, CENTRAL AND EASTERN ASIA Explanatory Note to the Metallogenic map of Northern–Central–Eastern Asia and Adjacent Areas at scale 1:2,500,000 VSEGEI Printing House St. Petersburg • 2017 Abstract Explanatory Notes for the “1:2.5 M Metallogenic Map of Northern, Central, and Eastern Asia” show results of long-term joint research of national geological institutions of Russia, China, Kazakhstan, Mongolia, and the Republic of Korea. The latest published geological materials and results of discussions for Uzbekistan, Kyrgyzstan, Tajikistan, Turkmenistan, and North Korea were used as well. Described metallogenic objects: 7,081 mineral deposits, 1,200 ore knots, 650 ore regions and ore zones, 231 metallogenic areas and metallogenic zones, 88 metallogenic provinces. The total area of the map is 30 M km2. Tab. 10, fig. 15, list of ref. 94 items. Editors-in-Chief: O.V. Petrov, A.F. Morozov, E.A. Kiselev, S.P. Shokalsky (Russia), Dong Shuwen (China), O. Chuluun, O. Tomurtogoo (Mongolia), B.S. Uzhkenov, M.A. Sayduakasov (Kazakhstan), Hwang Jae Ha, Kim Bok Chul (Korea) Authors G.A. Shatkov, O.V. Petrov, E.M. Pinsky, N.S. Solovyev, V.P. Feoktistov, V.V. Shatov, L.D. Rucheykova, V.A. Gushchina, A.N. Gureev (Russia); Chen Tingyu, Geng Shufang, Dong Shuwen, Chen Binwei, Huang Dianhao, Song Tianrui, Sheng Jifu, Zhu Guanxiang, Sun Guiying, Yan Keming, Min Longrui, Jin Ruogu, Liu Ping, Fan Benxian, Ju Yuanjing, Wang Zhenyang, Han Kunying, Wang Liya (China); Dezhidmaa G., Tomurtogoo O. (Mongolia); Bok Chul Kim, Hwang Jae Ha (Republic of Korea); B.S. Uzhkenov, A.L.
    [Show full text]
  • A Novel Conceptual Model of Intrusion Related Gold Bearing Systems And
    Studia UBB Geologia, 2020, 63 (1), 1 – 12 A novel conceptual model of intrusion related gold bearing systems and exploration tools Eugen Orlandea1 & Şerban-Nicolae Vlad2 1Ferdomin SpA, Calle Almirante Latorre, 151, 1530000, Copiapo, Atacama, Chile 2Babeş-Bolyai University, Department of Geology, Kogălniceanu 1, 400084 Cluj-Napoca, Romania Received: May 2019; accepted February 2020 Available online 11 February 2020 DOI: https://doi.org/10.5038/1937-8602.63.1.1304 Abstract. Despite numerous debates conducted in the last two decades, the concept of intrusion related gold systems IRGS remains controversial and sometimes befuddling. The key issue drifts from case to case, i.e., initial to subsequent proposed classifications, presence of gold in reduced fluids-porphyritic environments, non-porphyry gold in orogenic terrains and participation of non-magmatic gold fluids in depositional processes. Trying to avoid atypical or particular aspects of certain deposits, a genuine metallogenetic depiction intends to enhance the intrusion related systems meaning. Gold is either a major constituent or a mere byproduct. A vertical metal zonation develops from surface to depth: Au, Ag Cu, Pb, Zn Cu, Au Cu, Mo (Au), W Fe, Cu, Au (Co,W) U, Ce, La. Whether the relationship between different intrusion related occurrences is well known at shallow depth (epithermal, mesothermal, porphyry), so far less knowledge and understanding is assigned to deep seated mineralization (porphyry, Iron Oxides- Copper-Gold/IOCG). A specific relationship between those two deep seated ore styles emerges, that is the IOCG, confined to magmatic-hydrothermal type, is situated in the root zone of a deep porphyry system. Complementary information about updated classic exploration tools encompasses specifically geochemical association, geophysical signature, key alteration minerals, Au/Ag ratio and, last but not least, type minerals that contain/include gold in each intrusion related environment.
    [Show full text]
  • The Metamorphism of the Cambrian Basic Volcanic Rocks of Tasmania and Its Relationship to the Geosynclinal Environ­ Ment
    PAPlilllS AND PROCEEDINGS OF THE ROYAL SOCI>lTY OF TASMANIA, VOLUMB 88 The Metamorphism of the Cambrian Basic Volcanic Rocks of Tasmania and its Relationship to the Geosynclinal Environ­ ment By BERYL SCOTT, B.SC., PH.D. (With 4 Plates and 2 Text Ji'igwres) ABSTRACT A spilitic suite comprising picrite basalts, spilites, keratophyres, albite dolerites and associated pyroclastics of Middle and Upper Cambrian age, outcrops on the North-Vi/est and West Coast of Tasmania. The spilites and keratophyres are considered to have been normal basalts which later suffered soda metasomatism as a result of geosynclinal depOl::,ition and orogeny. Hydrothermal alteration of the volcanics has also given rise to a variety of other rock types which includes porphyries, variolite, spherulitic quartz rock and jasper. INTRODlJCTION While the author was resident in Tasmania, a detailed petrographie study was made of the Cambrian volcanle rocks of the State and the results were submitted to the University of Tasmania as a thesis for the degree of Doctor of Philosophy in 1952. Several papers have already been published on this work (Scott, 1952), but after leaving Tasmania it was thought necessary to publish a general summary of the whole study even though the interpretations may not be eonelusive. Mueh confusion exists in the literature dealing with the volcanics of the 'Vest Coast of Tasmania. The igneous rocks have been referred to as porphyroids, keratophyres, quartz and feldspar porphyries, andesites, melaphyres and syenites. The present author believes that the greater part of the volcanics was essentially basic in composition, probably basalts and porphyritic basalts, with or without amygdales, and their corresponding pyroclastics.
    [Show full text]
  • Ambient Groundwater Quality of Tlie Douglas Basin: an ADEQ 1995-1996 Baseline Study
    Ambient Groundwater Quality of tlie Douglas Basin: An ADEQ 1995-1996 Baseline Study I. Introduction »Ragstaff The Douglas Groundwater Basin (DGB) is located in southeastern Arizona (Figure 1). It is a picturesque broad alluvial valley surrounded by rugged mountain ranges. This factsheet is based on a study conducted in 1995- 1996 by the Arizona Department of Enviroimiental Quality (ADEQ) and Douglas summarizes a comprehensive regional Groundwater groundwater quality report (1). Basin The DGB was chosen for study for the following reasons: • Residents predominantly rely upon groundwater for their water needs. • There is a history of management decrees designed to increase groundwater sustainability (2). • The basin extends into Mexico, making groundwater issues an international concern. II. Background The DGB consists of the southern portion of the Sulphur Springs Valley, a northwest-southeast trending trough that extends through southeastern Arizona into Mexico. Covering 950 square miles, the DGB is roughly 15 miles wide and 35 miles long. The boundaries of the DGB include the Swisshelm (Figure 2), Pedregosa, and Perilla Mountains to the east, the Mule and Dragoon Mountains to the west, and a series of small ridges and buttes to * AguaPrieta the north (Figure 1). Although the Mexico DGB extends south hydrologically into Figure 1. Infrared satellite image of the Douglas Groundwater Basin (DGB) taken in June, 1993. Mexico, the international border serves Irrigated farmland is shown in bright red in the central parts of the basin, grasslands and mountain as the southern groundwater divide for areas appear in both blue and brown. The inset map shows the location of the DGB within Arizona.
    [Show full text]
  • Vegetation As an Indicator of Rock Types in the Northern Swisshelm Mountains, Southeastern Arizona
    Vegetation as an indicator of rock types in the northern Swisshelm Mountains, southeastern Arizona Item Type text; Thesis-Reproduction (electronic) Authors Bradbury, David E. (David Edwin), 1944- Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 02/10/2021 15:34:13 Link to Item http://hdl.handle.net/10150/552052 VEGETATION AS AN INDICATOR OF ROCK TYPES IN THE NORTHERN SWISSHELM MOUNTAINS, SOUTHEASTERN ARIZONA by David Edwin Bradbury A Thesis Submitted to the Faculty of the DEPARTMENT OF GEOGRAPHY AND AREA DEVELOPMENT In Partial Fulfillment of the Requirements For the Degree of MASTER OF ARTS WITH A MAJOR IN GEOGRAPHY In the Graduate College THE UNIVERSITY OF ARIZONA 19 6 9 STATEMENT BY AUTHOR This thesis has been submitted in partial fulfill­ ment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this thesis are allowable without special permission, provided that accurate acknowl­ edgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his judgment the proposed use of the material is in the inter­ ests of scholarship.
    [Show full text]
  • Resume of the Geology of Arizona," Prepared by Dr
    , , A RESUME of the GEOWGY OF ARIZONA by Eldred D. Wilson, Geologist THE ARIZONA BUREAU OF MINES Bulletin 171 1962 THB UNIVBR.ITY OP ARIZONA. PR••• _ TUC.ON FOREWORD CONTENTS Page This "Resume of the Geology of Arizona," prepared by Dr. Eldred FOREWORD _................................................................................................ ii D. Wilson, Geologist, Arizona Bureau of Mines, is a notable contribution LIST OF TABLES viii to the geologic and mineral resource literature about Arizona. It com­ LIST OF ILLUSTRATIONS viii prises a thorough and comprehensive survey of the natural processes and phenomena that have prevailed to establish the present physical setting CHAPTER I: INTRODUCTION Purpose and scope I of the State and it will serve as a splendid base reference for continued, Previous work I detailed studies which will follow. Early explorations 1 The Arizona Bureau of Mines is pleased to issue the work as Bulletin Work by U.S. Geological Survey.......................................................... 2 171 of its series of technical publications. Research by University of Arizona 2 Work by Arizona Bureau of Mines 2 Acknowledgments 3 J. D. Forrester, Director Arizona Bureau of Mines CHAPTER -II: ROCK UNITS, STRUCTURE, AND ECONOMIC FEATURES September 1962 Time divisions 5 General statement 5 Methods of dating and correlating 5 Systems of folding and faulting 5 Precambrian Eras ".... 7 General statement 7 Older Precambrian Era 10 Introduction 10 Literature 10 Age assignment 10 Geosynclinal development 10 Mazatzal Revolution 11 Intra-Precambrian Interval 13 Younger Precambrian Era 13 Units and correlation 13 Structural development 17 General statement 17 Grand Canyon Disturbance 17 Economic features of Arizona Precambrian 19 COPYRIGHT@ 1962 Older Precambrian 19 The Board of Regents of the Universities and Younger Precambrian 20 State College of Arizona.
    [Show full text]