DOCSLIB.ORG

RS-35 Alkalic Igneous Rocks of Colorado and Their Associated Ore

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
RS-35 Alkalic Igneous Rocks of Colorado and Their Associated Ore CGS LIBRARY RESOURCE SERIES 35 Alkalic Igneous Rocks of Colorado and Their Associated Ore Deposits By james A. Cappa Colorado Geological Survey Department of Natural Resources Denver, Colorado 1998 - I ' - ..... / I / ,/--.1I - , / , / ,/I ...... _I or "blowout" I - \ _ I - \ Tbr Resource Series 35 Alkalic Igneous Rocks of Colorado and Their Associated Ore Deposits By James A. Cappa Colorado Geological Survey Department of Natural Resources Denver, Colorado 1998 CGS LIBRARY Resource Series 35 Contents Preface ......................................................... Vll· · Biotite Latite Porphyry ............... .. 13 Acknowledgements ...................................... vii Hornblende Granodiorite Porphyry ............................. .. 13 I. Survey of Alkalic Igneous Rocks ................ I Structure ........................................... 13 Introduction .............................................. 1 Geochemistry .......................................... 13 Composition .................................................. .1 Economic Geology .................................. 13 Tectonic Setting .............................................. .1 Veins and Fracture Fillings ................. 14 Continental Rift Valley Magmatism .......... 1 Vein mineralogy........................... 14 Oceanic and Continental Zoning ........................................ 16 Intraplate Magmatic Setting ........... 3 Alteration .................................. .. 17 Subduction Related Magmatism .......... 3 Paragenesis ................................ .. 17 Classification ............................................ 3 Vein control ................................. 17 Ore Deposits ............................................. 3 Stockworks ........................................ 17 Niobium and Tantalum ........................ 3 Magma tic Segregations ...................... 18 Rare Earth Elements including Origin and Model of Ore Deposits ..... 18 Yttrium ......................................... 4 Exploration and Production History ........ 19 Zirconium and Hafnium ...................... 4 References ............................................... 2 0 Vermiculite ......................................... .4 Diamonds-Kimberlites and 3. Cripple Creek District ............................ 23 Lamproites .................................. .. 4 Introduction ............................................ 23 Gold .................................................... 5 Geological Setting ...................................23 Molybdenum ....................................... 5 Proterozoic Rocks .............................. 23 Iron ..................................................... 6 Oligocene Volcanic and Titanium ............................................. 6 Volcaniclastic Rocks ..................... 23 Uranium and Thorium ........................ 6 Oligocene Diatreme Complex ............ 23 B . Other .................................................. 6 reccla ......................................... 24 References ................................................. 6 Phonolite ..................................... 26 syemte . ....................................... 26 2. Central Front Range Mineral Belt.. ........... 9 Trachybasalt ................................ 26 Introduction .............................................. 9 Structure ........................................... 27 Geological Setting ..................................... 9 Geochemistry .......................................... 27 Proterozoic Metamorphic Rocks ........ 11 Economic Geology .................................. 27 Proterozoic Quartzite ........................ .11 Vein Deposits .................................... 2 7 Proterozoic Granodiorite ................... .11 Diatreme-Hosted Deposits ................. 29 Proterozoic Granites-Younger. ........... .11 Hydrothermal Breccia Deposits .......... 29 Cretaceous-Tertiary Intrusive Rocks ... 11 Bedded Rock-Hosted Deposits .......... 31 Leucocratic Granodiorite Origin of the Ore Deposits ................ .32 Porphyry .............................. 12 Exploration and Production History ...... .. 32 Alkalic Syenite Porphyry .......... ... 12 References ............................................... 3 3 Quartz Monzonite Porphyry ........ 12 Bostonite Porphyry ..................... 12 4. State Line Kimberlite District ................. 35 Trachytic Granite Porphyry .......... 12 Introduction ............................................ 35 Quartz Bostonite Porphyry .......... 12 Geological Setting .................................. .35 Limburgite Porphyry ................... 12 Gneiss .............................................. 35 iii Resource Series 35 . ...55 Virginia Dale Ring Complex .............. 35 Mancos FormatiOn ........... ········ . ...55 Diorite ......................................... 35 Browns Par k Formation .............. Sherman Granite .......................... 36 Tertiary Porphyritic Intrusive Trail Creek Granite ................. 36 andE xtrus1ve. R oc k s .............. · ..... 55 Cap Rock Quartz Monzonite .. 36 Structure ................................. ···· ...... 57 Log Cabin Granite ....................... 36 Hydrothermal Alteration .................. ·57 Phanerozoic Sediments ............... ....... 38 G eoc h em1s. t ry ................................... ...... 57 Structure ........................................... 38 Economic Geology .................................. 57 Geochemistry .......................................... 39 Exploration and Production History ...... .. 58 Economic Geology .................................. 39 References .................... ··························· 58 Origin of Ore Deposits ...................... .42 7. Iron Hill Alkalic Complex ....................... 61 Exploration and Production History ....... .43 Powderhorn District ................ ···· .. · ........ · 61 References ...............................................45 Introduction ............................................ 61 5. La Plata District .................................... .4 7 Geological Setting .......................... · ........ 61 Introduction ........................................ ... 47 Pyroxenite ......................................... 62 Geological Setting ................................... 47 Uncompahgrite ................................. 63 Paleozoic Sedimentary Rocks ............. 49 Nepheline Syenite ............................. 63 Hermosa Formation .................... .49 Carbonatite ....................................... 63 Rico Formation ......................... ... 49 Geochemistry .......................................... 64 Cutler Formation .........................49 Economic Geology .................................. 64 Mesozoic Sedimentary Rocks .......... ... 49 Thorium ............................................ 64 Dolores Formation ...................... 49 Niobium ............................................ 66 Entrada Sandstone ...................... .49 Titanium ........................................... 66 Wanakah Formation .................... 49 Rare-Earth Elements .......................... 66 Junction Creek Sandstone ............ 49 Iron ................................................... 67 Morrison Formation .................... 49 Uranium ........................................... 67 Dakota Sandstone ....................... .49 Vanadium .......................................... 67 Mancos Formation ..................... .. 49 Exploration and Production History ........ 67 Laramide Intrusive Rocks ................ .. 49 References ............................................... 6 7 Porphyritic Rocks ...................... .. 49 8. Silver Cliff and Rosita Hills District ......... 69 Equigranular Rocks .............. ....... 50 Introduction ............................................ 69 Structure ........................................ ... 50 Geological Setting ................................... 69 Geochemistry ......................................... 50 Proterozoic Undifferentiated .............. 69 Economic Geology .................................. 50 Rosita Hills Complex ......................... 70 Quartz-Tell uri de Veins ....................... 50 Rhyolite Flows and Volcaniclastic Telluride Replacement Bodies ............ 51 Rocks, Oligocene .................... 70 Gold-Bearing Exoskarns .................... 53 Rosita Andesite, Oligocene ........... 72 Quartz-Gold-Sulfide Veins and Hornblende Andesite, Miocene .... 72 Replacement Bodies ..................... 53 Rhyodacite of Bald Mountain, Breccias ............................................. 53 Miocene ................................. 72 Copper Porphyry-Type Deposits ........ 53 Rhyolite of Rosita Volcano, Exploration and Production History .... .... 54 Miocene ................................. 72 References ............................................... 54 Bunker Trachyandesite, Miocene .. 72 6. Hahns Peak District ................................ SS Pringle Latite, Miocene ................ 72 Introduction ............................................ 55 Trachyte of Game Ridge, Geological Setting ................................... 55 Miocene ................................. 72 Mesozoic to Cenozoic Rhyolite Porphyry of Antrim Sedimentary Rocks ...................... 55 Lode, Miocene ....................... 72 Morrison Formation ..................... 55 Silver Cliff Complex .......................... 72 Dakota Formation ........................ 55 iv
Load more

Recommended publications
  • Fort Davy Crockett: Browns Park National Wildlife Refuge (Colorado)
    U.S. FISH AND WILDLIFE SERVICE: REGION 6 - CULTURAL RECOURSE PROGRAM Fort Davy Crockett?: An Archaeological Mystery Browns Park National Wildlife Refuge – Northwest Colorado Summarized from: A Report on the Results of Limited Subsurface Testing at 5MF5478, a Proposed Site of Historic Fort Davy Crockett, Moffat County, Colorado Kristen D. Kent and Mona C. Charles, Department of Anthropology, Fort Lewis College, Durango, Colorado December 2004 Introduction The follow excerpts are from a 2004 report documenting archaeological testing at the possible location of Fort Davy Crocket on the Brown’s Park National Wildlife Refuge. Many studies and much research has been conducted over the years to try and determine if the remains found on a bluff overlooking the Green River on the Browns Park National Wildlife Refuge are indeed those of the Fort. This research adds additional insight into the mystery. Fort Davy Crockett In 1837 three fur trappers, Prewett Sinclair, Philip Thompson, and William Criag, formed a partnership and reportedly built Fort Davy Crockett that same year. The Fort was named after the famous Tennessee frontiersman who died at the Battle of the Alamo in Texas the previous year. Kit Carson, another famous frontiersman, trapper and scout is reported to have been employed by the owners of Fort Davy Crockett. In 1839 members of the Peoria Party on their way to Oregon reported staying at the Fort. A description of the Fort was provided in the recordings of Thomas Jefferson Farnham, leader of the Peoria Party. He described the Fort thus: The fort, as it is called, peered up in the centre, upon the winding banks of the Sheetskadee.
    [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]
  • COLORADO CONTINENTAL DIVIDE TRAIL COALITION VISIT COLORADO! Day & Overnight Hikes on the Continental Divide Trail
    CONTINENTAL DIVIDE NATIONAL SCENIC TRAIL DAY & OVERNIGHT HIKES: COLORADO CONTINENTAL DIVIDE TRAIL COALITION VISIT COLORADO! Day & Overnight Hikes on the Continental Divide Trail THE CENTENNIAL STATE The Colorado Rockies are the quintessential CDT experience! The CDT traverses 800 miles of these majestic and challenging peaks dotted with abandoned homesteads and ghost towns, and crosses the ancestral lands of the Ute, Eastern Shoshone, and Cheyenne peoples. The CDT winds through some of Colorado’s most incredible landscapes: the spectacular alpine tundra of the South San Juan, Weminuche, and La Garita Wildernesses where the CDT remains at or above 11,000 feet for nearly 70 miles; remnants of the late 1800’s ghost town of Hancock that served the Alpine Tunnel; the awe-inspiring Collegiate Peaks near Leadville, the highest incorporated city in America; geologic oddities like The Window, Knife Edge, and Devil’s Thumb; the towering 14,270 foot Grays Peak – the highest point on the CDT; Rocky Mountain National Park with its rugged snow-capped skyline; the remote Never Summer Wilderness; and the broad valleys and numerous glacial lakes and cirques of the Mount Zirkel Wilderness. You might also encounter moose, mountain goats, bighorn sheep, marmots, and pika on the CDT in Colorado. In this guide, you’ll find Colorado’s best day and overnight hikes on the CDT, organized south to north. ELEVATION: The average elevation of the CDT in Colorado is 10,978 ft, and all of the hikes listed in this guide begin at elevations above 8,000 ft. Remember to bring plenty of water, sun protection, and extra food, and know that a hike at elevation will likely be more challenging than the same distance hike at sea level.
    [Show full text]
  • Subduction Cycles Under Western North America During the Mesozoic and Cenozoic Eras
    .. Geological Society of America Special Paper 299 1995 Subduction cycles under western North America during the Mesozoic and Cenozoic eras Peter L. Ward U.S. Geological Survey, 345 Middlefield Road, MS 977, Menlo Park, California 94025 ABSTRACT An extensive review of geologic and tectonic features of western North America suggests that the interaction of oceanic plates with the continent follows a broad cycli- cal pattern. In a typical cycle, periods of rapid subduction (7-15 cdyr), andesitic vol- canism, and trench-normal contraction are followed by a shift to trench-normal extension, the onset of voluminous silicic volcanism, formation of large calderas, and the creation of major batholiths. Extension becomes pervasive in metamorphic core complexes, and there is a shift to fundamentally basaltic volcanism, formation of flood basalts, widespread rifting, rotation of terranes, and extensive circulation of flu- ids throughout the plate margin. Strike-slip faulting becomes widespread with the creation of new tectonostratigraphic terranes. A new subduction zone forms and the cycle repeats. Each cycle is 50-80 m.y. long; cycles since the Triassic have ended and begun at approximately 225, 152, 92, 44, and 15 Ma. The youngest two cycles are diachronous, one from Oregon to Alaska, the other from central Mexico to Califor- nia. The transitions from one cycle to the next cycle are characterized by rapid and pervasive changes termed, in this chapter, “major chaotic tectonic events.” These events appear to be related to the necking or breaking apart of the formerly sub- ducted slab at shallow depth, the resulting delamination of the plate margin, and the onset of a new subduction cycle.
    [Show full text]
  • Petrography of Radioactive Tertiary Igneous Rocks Front Range Mineral Belt Colorado
    Petrography of Radioactive Tertiary Igneous Rocks Front Range Mineral Belt Colorado GEOLOGICAL SURVEY BULLETIN 1032-E Prepared on behalf of the United States Atontic Energy Commission and pub­ lished with the permission of the Commission Petrography of Radioactive Tertiary Igneous Rocks Front Range Mineral Belt '·colorado By]. D. WELLS GEOLOGY AND ORE DEPOSITS OF CLEAR CREEK, GILPIN, AND LARIMER COUNTIES, COLORADO GEOLOGICAL SURVEY BULLETIN 1032-E Prepared on behalf of the United States Atomic Energy Commission and pub­ lished with the permission of the Commission UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON • 1960 UNITED STATES DEPARTMENT OF THE INTERIOR FRED A. SEATON, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U S. Government Prlntln~ Office Washln~ton 25, DC. CONTENTS Page Abstract------------------------------------------------------~--- 223 Introduchon------------------------------------------------------ 224 GeologiC settmg__ --------------------- _ --- ________ -------- _ ----- _ _ 227 Form of mtrusive rocks _______ --------- __ -- _________ --- __ ----______ 228 Age and sequence of mtruswn_______________________________________ 228 Texture and mternal structures-------------------------------------- 230 PetrographY------------------------------------------------------ 231 ClassificatiOn _______ -----_-----_--- _____ ---_----------___________ 231 DescriptiOn of rocks_____________________________________________ 232 Light-coloicd granod10nte group_________________________________
    [Show full text]
  • Geologic Studies of the Platte River, South-Central Nebraska and Adjacent Areas—Geologic Maps, Subsurface Study, and Geologic History
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Publications of the US Geological Survey US Geological Survey 2005 Geologic Studies of the Platte River, South-Central Nebraska and Adjacent Areas—Geologic Maps, Subsurface Study, and Geologic History Steven M. Condon Follow this and additional works at: https://digitalcommons.unl.edu/usgspubs Part of the Earth Sciences Commons Condon, Steven M., "Geologic Studies of the Platte River, South-Central Nebraska and Adjacent Areas—Geologic Maps, Subsurface Study, and Geologic History" (2005). Publications of the US Geological Survey. 22. https://digitalcommons.unl.edu/usgspubs/22 This Article is brought to you for free and open access by the US Geological Survey at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Publications of the US Geological Survey by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Geologic Studies of the Platte River, South- Central Nebraska and Adjacent Areas—Geologic Maps, Subsurface Study, and Geologic History Professional Paper 1706 U.S. Department of the Interior U.S. Geological Survey Geologic Studies of the Platte River, South-Central Nebraska and Adjacent Areas—Geologic Maps, Subsurface Study, and Geologic History By Steven M. Condon Professional Paper 1706 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey Charles G. Groat, Director Version 1.0, 2005 This publication and any updates to it are available online at: http://pubs.usgs.gov/pp/pp1706/ Manuscript approved for publication, March 3, 2005 Text edited by James W. Hendley II Layout and design by Stephen L.
    [Show full text]
  • Supergene Mineralisation of the Boyongan Porphyry Copper-Gold Deposit, Surigao Del Norte, Philippines
    Supergene Mineralisation of the Boyongan Porphyry Copper-Gold Deposit, Surigao del Norte, Philippines by Allan Maglaya Ignacio B.Sc. Geology, National Institute of Geological Sciences University of the Philippines Thesis submitted in partial fulfilment of the requirements of the Masters of Economic Geology Degree Centre for Ore Deposit Research, University of Tasmania December, 2005 DECLARATION OF ORIGINALITY This thesis contains no material which has been accepted for a degree of diploma by the University of Tasmania or any other institution, except by way of background information and duly acknowledged in the thesis, and contains no previous material previously pub- lished or written by another person except where due acknowledgement is given. Allan Maglaya Ignacio 01 December 2005 _________________________ STATEMENT OF AUTHORITY OF ACCESS This thesis may not to be made available for loan or copying for 1.5 years following the date this statement was signed. Following that time, the thesis may be available for loan and lim- ited copying in accordance with Copyright Act 1968. Allan Maglaya Ignacio 01 December 2005 _________________________ TABLE OF CONTENTS Page (s) LIST OF FIGURES …………………………………………………….. i - iii LIST OF APPENDICES ………………………………………………… iv ACKNOWLEDGMENTS ………………………………………………. v ABSTRACT ……………………………………………………………... vi - vii 1.0 INTRODUCTION ………………………………………………………. 1 - 8 1.1 Introduction …………………………………………………………. 1 1.2 Aims and Objectives ……………………………………………….. 1 1.3 Methods Employed …………………………………………………. 2 1.4 Location and Accessibility …………………………………………. 3 1.5 Climate ……………………………………………………………... 5 1.6 Previous Work ……………………………………………………… 5 2.0 GEOLOGICAL SETTING ………………………………………………. 9 - 37 2.1 Introduction ………………………………………………………. 9 2.2 Regional Tectonics …………….…………………………………. 9 2.3 Regional and Local Stratigraphy ………………………………... 11 2.3.1 Basement (Cretaceous-Paleogene) ………………………. 11 2.3.2 Bacuag Formation (Oliogocene-Miocene) .……………..
    [Show full text]
  • Mineral Occurrence and Development Potential Report Rawlins Resource
    CONTENTS 1.0 INTRODUCTION......................................................................................................................1-1 1.1 Purpose of Report ............................................................................................................1-1 1.2 Lands Involved and Record Data ....................................................................................1-2 2.0 DESCRIPTION OF GEOLOGY ...............................................................................................2-1 2.1 Physiography....................................................................................................................2-1 2.2 Stratigraphy ......................................................................................................................2-3 2.2.1 Precambrian Era....................................................................................................2-3 2.2.2 Paleozoic Era ........................................................................................................2-3 2.2.2.1 Cambrian System...................................................................................2-3 2.2.2.2 Ordovician, Silurian, and Devonian Systems ........................................2-5 2.2.2.3 Mississippian System.............................................................................2-5 2.2.2.4 Pennsylvanian System...........................................................................2-5 2.2.2.5 Permian System.....................................................................................2-6
    [Show full text]
  • Evolution of the White Mountain Magnia Series
    EVOLUTION OF THE WHITE MOUNTAIN MAGNIA SERIES RaNoor.pn W. CnapuaN, Vassar College CnenrBs R. wrr";;: , Cambri.d,ge,Mass. PART I. DATA Pnosr.BM In recent years, a number of intensive field and laboratory studies of the rocks of the White Mountain district in New Hamp- shire have been carried out. One result of these investigations is to show that there exists in this area a group of rocks with marked alkaline affinities (3)* to which the name White Mountain magma serieshas been applied (5, p.56). The various rock types of this group form a definite series,and wherever found in the area they possessthe same relative ages.Such a sequenceis of greatestim- portance to petrology and necessitatesan explanation. Accord- ingly, the writers have undertaken a study of this problem, the results of which are presented in this paper. ft is not pretended that this work is complete or that the problem has been entirely solved. Certain definite conclusions have been reached, however, and it is hoped that these may lead to a more complete under- standing of the evolution of the White Mountain magma series. The writers are especiallyindebted to ProfessorMarland Billings of Harvard University for his valuable assistancein preparing this paper. Several of the major ideas presentedhere were first sug- gested by Professor Billings, and these have led to a clearer under- standing of many of the intricate problems encountered in the course of the work. The writers also wish to thank ProfessorEsper S. Larsen, Jr., and ProfessorR. A. Daly for their many helpful suggestionsand criticisms.
    [Show full text]
  • University Ox Nevada Reno Geology, Geotechnical Properties And
    University ox Nevada - Reno Reno Reno, Key; ;v5 57 geology, Geotechnical Properties and Vesicular Rock Classification of 1onsetown Basalts and Latites, Truckee Area, California A thesis submitted in partial fulfillment ox the requirements for the degree of Master of Science in Geological Engineering far L J Joseph G. Franzone May 1980 HftWttiS U M A I 'f fj'h.i s thesis of Joseph 0. Iran zone is approved: University of Revada. Reno May 19B0 ii ACKNOW LEBGEMENT 3 I am indebted to several people for the assistance and encouragement they gave me dui’ing the preparation of this thesis. Professional advisement of the project and critical reviewing of the manuscript were provided by Sr. Robert J. Watters, Dr. Joseph Lints, Jr. and Dr. Y. S. Kim. Dr. Y. S. Kira graciously made the Rock Mechanics Laboratory and testing equipment available. Dr. Robert J. Watters also allowed unlimited freedom to the Geological Engineering Laboratory equipment and also, along with Dr. Joseph Lintz, Jr., provided invaluable guidance throughout the thesis preparation. Appreciation for help in de-bugging the laboratory equipment goes to my colleague, Ken Krank. Finally, and most importantly, I am indebted to my parents who, whenever I needed them, were always present and supportive. ABSTRACT Geology, physical and engineering properties of the rock units of the lousetown Basalts and Latites in the Trucked Area, California were determined by field and laboratory testing and field ODservations. Of the 16 properties that were calculated for massive samples, 8 were shown to be capable of preuicting i^-e compressive strength and 10 were shown to be capable of predicting the Elastic Modulus.
    [Show full text]
  • Grand County Master Plan Was Adopted by the Grand County Planning Commission on ______, 2011 by Resolution No
    Grand County Department of Planning and Zoning February 9, 2011 GRAND COUNTY PLANNING COMMISSION Gary Salberg, Chairman Lisa Palmer, Vice-Chair Sally Blea Steven DiSciullo George Edwards Karl Smith Ingrid Karlstrom Mike Ritschard Sue Volk GRAND COUNTY BOARD OF COUNTY COMMISSIONERS James L. Newberry, Commissioner District I Nancy Stuart, Commissioner District II Gary Bumgarner, Commissioner District III The Grand County Master Plan was adopted by the Grand County Planning Commission on __________________, 2011 by Resolution No. ______________. The Master Plan was prepared by: Grand County Department of Planning & Zoning, 308 Byers Ave, PO Box 239, Hot Sulphur Springs, CO 80451 (970)725-3347 and Belt Collins 4909 Pearl East Circle Boulder, CO 80301 (303)442-4588 Table of Contents Acknowledgements .....................................................................................................................................iv Chapter 1 Planning Approach & Context .................................................................................................1 Chapter 2 Building a Planning Foundation .............................................................................................17 Chapter 3 Plan Elements ...........................................................................................................................32 Chapter 4 Growth Areas, Master Plan Updates & Amendments ..........................................................51 Appendix A Growth Area Maps ...............................................................................................................53
    [Show full text]
  • (Hypogene) Sulphate Minerals in Ore Deposits2
    ECONOMIC GEOLOGY WITH WHICH IS INCORPORATED THE AMERICAN GEOLOGIST VOL. XIV DECEMBER, I9I 9 No. 8 PRIMARY (HYPOGENE) SULPHATE MINERALS IN ORE DEPOSITS2 B. S. BUTLER. CONTENTS. PAOE. Introduction ......................................................... Sulphate Minerals .................................................... Character of Ore Solutions as Indicated by Volcanic Emanations ....... 590 Conditions of Format'ion of Sulphur Trioxide ......................... 593 Formation of Sulphuric Acid in Nature ............................... 594 Formation of Primary Sulphate Minerals ............................. 596 Summary ............................................................ 6o8 Acknowledgment .................................. -................... 609 INTRODUCTION. In studyingore depositsthe writer has severaltimes been con.- fronted with the problemof accountingfor the formation of sulphateminerals that are apparentlyprimary. These minerals occur at placeswhere no evidencecan be found of their forma- tion by surface oxidation. Either they were formed directly 'by igneousemanations or, if they were formed by surfaceagencies, those agenciesmust have effectedthe depositionof other asso- ciatedminerals that would ordinarily •beregarded as of hypogene origin. An attemptwill be madeto analyzethis problemby start- ing with the belief, 'basedon deductionsfrom field observations, that the sulphatesin certaindeposits have •een formed directlyby x Published by permission of the Director, United State Geological Survey. 58x 5.82 B. S. BUTLER.
    [Show full text]