 | | Report (volume) | | of the Freeland-Lamartine District, Clear Creek County, Colorado GEOLOGICAL SURVEY BULLETIN This report...of the Freeland-Lamartine District, Clear Creek County, Colorado By J. E. HARRISON and J. D. WELLS GEOLOGY...GEOLOGY AND ORE DEPOSITS OF CLEAR CREEK, GILPIN, AND LARIMER COUNTIES, COLORADO GEOLOGICAL SURVEY BULLETIN...Pre-Cambrian rocks...____________________________ _ Idaho Springs formation___________________________ Biotite-quartz...mine. CONTENTS V Page FIGURE 3. Index map of Colorado showing the location of the FreelandLamartine |  | | Report (issue) | | Qiiartzite-Schist Sequence Along Coal Creek to Idaho Springs Formation Front Range, Colorado By JOHN D. WELLS, DOUGLAS...Boulder Creek Granite and the quartz monzonite_ __________-__-__---_----_--_-_---_-Boulder Creek Granite...the Coal Creek areaIn pocket FIGUBE 1. Index maps of the Coal Creek area, Eldorado Springs, Ralston Buttes...cordierite. 12 4. Triangular diagram of Boulder Creek Granite.______________________ 13 5. Triangular...QUARTZITE-SCHIST SEQUENCE ALONG COAL CREEK TO IDAHO SPRINGS FORMATION, FRONT RANGE, COLORADO By JOHN D. WELLS, DOUGLAS |  | | Journal (article/letter/editorial) | | PEGMATITES OF EIGHT MILE PARK, FREMONT COUNTY, COLORADOXT E. Wrrr. HerNnrcu, Department of Mineralogy...to twelve miles west of Canon City, Fremont County, Colorado, includes about 30 square miles that lie at...separate paper. 420 PEGMATITES OF EIGHT MILE PARK, COLORADO 42r area are flanked on the east by hogbacks...granite, Idaho Springs schist, and injection gneiss. The oldest, the Idaho Springs formation, consists...formed by large scale lit-par-lit intrusion of Idaho Springs biotite schists by granite, aplite, and pegmatite |  | | Report (issue) | | QlJADRANGLE (TOGETHER 'VITH THE EMPIRE DISTRICT) COLORADo· BY JOSIAH E. SPURR AND GEORGE H. GARREY WITH..................._.......... . Distribution in Colorado ................................................. . . . . . . . . . . . . . . . . . . . 97 Idaho Springs auriferous area. __ ............. _.. _. _....Boulder County.............. . . . . . . . . . . . ......... . ....... . 103 Ores in Gilpin County ............................... . 103 Orcs in Clear Creek County ............................ . 103 Ores from |  | | Report (issue) | | PRELIMINARY REPORT ON THE ECONOMIC GEOLOGY OF GILPIN COUNTY, COLORADO. By EDSON S. BASTIN and JAMES M. HiLL.1 INTRODUCTION...the economic geology of Gilpin County and adjacent portions of Clear Creek and Boulder counties, Colo.,...Mountains. It is the oldest lode-mining region in Colorado, and its discovery in 1859 was the occasion of...productive portions of Gilpin County and small adjacent parts of Boulder and Clear Creek counties, all within...Gilpin County, Central City, Blackhawk, Nevadaville, Eussell Gulch, Perigo, and Apex; in Clear Creek County |  | | Journal (article/letter/editorial) | | PRECAMBRIAN ROCKS OF THE HALL VALLEY AREA, FRONT RANGE, COLORADO BY ERNEST E. WAHLSTROM AND OK JOON KIM ABSTRACT...The Hall Valley area, in northwestern Park County, Colorado, contains foliated highgrade Precambrian metamorphic...argument against continued use of the terms Idaho Springs formation and Swandyke gneiss for the metasedimentary...migmatization and granitization. (7) A body of Boulder Creek granodiorite was intruded into the northeast portion...Granitic rocks 1230 Migration of elements 1230 Boulder Creek granodiorite and Silver Plume granite 1233 Pegmatite |  | | Report (volume) | | (A) Geology of Precambrian rocks, Idaho Springs district, Colorado, by Robert H. Moench. (B) Geology...and iron content of rocks from the Red Mountain Formation, Alabama, by Richard P. Sheldon. (E) Investigations... Geology of Precambrian Rocks, Idaho Springs District, Colorado By ROBERT H. MOENCH CONTRIBUTIONS...of the Idaho Springs district____________ In pocket 2. Geologic sections of the Idaho Springs district...mapped by present and previous workers in the Idaho Springs district ____________________ ----- ________ |  | | Report (issue) | | REYNOLDS AREA LAWSON-DUMONT DISTRICT CLEAR CREEK COUNTY COLORADO By J. E. Harrison and B. F. Leonard ...REYNOLDS AREA LAWSON-DUMONT DISTRICT, CLEAR CREEK COUNTY, COLORADO By J. E. Harrison and B. F. Leonard...REYNOLDS AREA LAWSON-DUMONT DISTRICT, CLEAR CREEK COUNTY, COLORADO CONTENTS Page Abstract ...............units.................................... Idaho Springs formation................... Biotite-quartz-plagioclase...Sisters groups of claims. The area is in Clear Creek County, Colo., about three-fourths of a mile south |  | | Report (issue) | | Geology of Precambrian Rocks Central City District Colorado GEOLOGICAL SURVEY PROFESSIONAL PAPER 474-C Prepared... Geology of Precambrian Rocks Central City District Colorado By P. K. SIMS and D. J. GABLE SHORTER CONTRIBUTIONS...1918Geology of Precambrian rocks, Central City district, Colorado, by P. K. Sims and D. J. Gable. Washington, U...district, Colorado. 1964. (Card2) 1. Geology, Stratigraphic Pre-Cambrian. 2. Geology Colorado Gilpin Co...Gilpin County, Colorado. 2. Geologic sections of the Central City district, Gilpin County, Colorado. 3. |  | | Report (volume) | | Part of the Morrison Quadrangle Jefferson County, Colorado GEOLOGICAL SURVEY BULLETIN 1251-E Geology...Part of the Morrison Quadrangle Jefferson County, Colorado By D. J. GABLE CONTRIBUTIONS TO GENERAL GEOLOGY...rocks along the mountain front due west of Denver, Colorado UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON...PART OF THE MORRISON QUADRANGLE JEFFERSON COUNTY, COLORADO By D. J. GABLE ABSTRACT The Morrison quadrangle...This sequence, which is typical of the Idaho Springs Formation, was intruded, in Precambrian time, by |  | | Report (volume) | | Uranium Deposits of the Caribou Area, Boulder County Colorado GEOLOGICAL SURVEY BULLETIN This report concerns...Uranium Deposits of the Caribou Area, Boulder County Colorado By F. B. MOORE, W. S. CAVENDER, and' E. P....- - _________________ . Idaho Springs formation --______________ Boulder Creek granite____..________________...Point mine______-________-___ ________________ _ Idaho mine___________ ___________________ Gold mine_____...Plate 35. Geologic map of the Caribou area, Boulder County, Colo. 36. Composite map of the Caribou mine, showing |  | | Report (issue) | | Geology and Ore Deposits of the Front Range Colorado By T. S. LO\'ERING and E. N. GODDARD GEOLOGICAL...in cooperation with the Colorado State Geological Survey Board and the Colorado Metal Mining Fund ~ oopr...Metamorphic rocks ________________________ _ Idaho Springs formation _______________ _ Swandy ke hornblende...hornblende gneiss ____________ _ Quartzite at Coal Creek ________________ _ Igneous rocks _____________________________...Quartz diorite and associated hornblendite_ Boulder Creek granite _________________ _ Pikes Peak granite |  | | Journal (article/letter/editorial) | | SOME MINERAL OCCURRENCES IN THE GUFFEY REGION, COLORADO* Jeuos E. Bnven, []niversity of Michigan, Ann...north-central Fremont County and southeast Park County in the Front Range of central Colorado. Its center is...color. Associated are abundant coarsebiotite and magnetite as well as the other common granitic pegmatite...are beryl, schorl, tantalite, and smoky qtartz. Magnetite-guartz-sillimaniteseloage:The Whopper pegmatite...et al,. (1950, pp. a8-50) who report "granular magnetite massesas much as 3 inches in size and a mineral |  | | Report (volume) | | OF BOULDER COUNTY, COLORADO BY T. S. LOVERING Prepared in cooperation with the COLORADO METAL MINING...MINING FUND and the COLORADO GEOLOGICAL SURVEY BOARD Strategic Minerals Investigations, 1940 (Pages 135-156)...Page Plate 24. Map showing location of Boulder County tungsten belt and general regional geology................In pocket 25. Geologic map of Boulder County tungsten belt and adjacent area..................25. Ferberite concentrates produced in Boulder County 1900-1938................. 136 26. Diagram representing |  | | Report (volume) | | Geology of the Platte Canyon Quadrangle Colorado By WARREN L. PETERSON CONTRIBUTIONS GEOLOGICAL TO...quadrangle. _ In pocket FIGURE 1. Index map of Colorado showing location of the Platte Canyon quadrangle...GEOLOGY GEOLOGY OF THE PLATTE CANYON QUADRANGLE, COLORADO By WARREN L. PETERSON ABSTRACT The Platte Canyon...Front Kange in Colorado (fig. 1). The quadrangle is accessible from the north by county roads that lead...Highway 285 and Colorado Highway 124, from the south by a county road that joins Colorado Highway 67, and |  | | Report (volume) | | the Lawson-DumontFall River District Clear Creek County Colorado By C. C. HAWLEY and FRANK BAKER MOORE...northwestern part of the important Central City-Idaho Springs mineralized area UNITED STATES GOVERNMENT PRINTING...section of the Lawson-Dumont-Fall River district, Clear County, Colo. 2. ~ap showing major faults (veins) of...THE LAWSONDUMONT-FALL RIVER DISTRICT, CLEAR CREEK COUNTY, COLORADO By C. C. HAWLEY and FRANK BAKER...is in Clear Creek County, Colo., just west of the highly productive Central City and Idaho Springs districts |  | | Report (volume) | | Geology of the Eldorado Springs Quadrangle Boulder and Jefferson , Counties, Colorado C_-J / By JOHN D. WELLS...___ Boulder Creek Granodiorite__________________________ Inclusions in the Boulder Creek Granodiorite_________...Sandstone_____--__--__-_-___---____________ Lykins Formation.__________________________________ Mesozoic r...rocks__________________________________________ Ralston Creek Formation.. __________________________ Morrison Form...ILLUSTRATIONS Page PLATE 1. Geologic map of the Eldorado Springs quadrangle..___.__In pocket FIGURE 1. Index map |  | | Journal (article/letter/editorial) | | REGIONAL METAMORPHISM IN THE NORTHERN FRONT RANGE, COLORADO Abstract: Rubidium-strontium dating of wholerock...A large part of the Precambrian terrane of the Colorado Front Range consists of schists and gneisses which...(Fig. 1). West of Golden, Colorado, these were named the Idaho Springs Formation by Ball (1906). The Idaho...extensive recrystallization. Granodiorite of Boulder Creek type and quartz diorite were emplaced during the...Generalized geologic map of the northern Front Range, Colorado (compiled from Osterwald and Dean, 1958; Tweto |  | | Report (issue) | | Geology and Ore Deposits of the Boulder County Tungsten District Colorado GEOLOGICAL SURVEY PROFESSIONAL ... Geology and Ore Deposits of the Boulder County Tungsten District Colorado By T. S. LOVERING and OGDEN TWETO...with the State of Colorado through the Colorado Geological Survey Board and the Colorado Metal Mining Fund...Pre-Cambrian rocks_____________________________ Idaho Springs formation_ _______________ Distribution ___...Age_ __________________________________ Boulder Creek granite and related rocks. ____ Distribution and |  | | Report (issue) | | General Geology of the Harold D. Roberts Tunnel, Colorado GEOLOGICAL SURVEY PROFESSIONAL PAPER 831-B General... General Geology of the Harold D. Roberts Tunnel, Colorado By CHARLES S. ROBINSON, LAWRENCE A. WARNER, and...ENGINEERING GEOLOGY OF THE HAROLD D. ROBERTS TUNNEL, COLORADO GEOLOGICAL SURVEY PROFESSIONAL PAPER 831-B......................................... Boulder Creek Granite...........................................Morrison Formation. Dakota Group............ Benton Shale.............. Niobrara Formation. Pierre Shale |  | | Journal (article/letter/editorial) | | ORES OF GILPIN E•soN COUNTY, COLORADO. S. BASTIN. INTRODUCTION. An exhaustive report on the economic...geology of Gilpin County and adjacentportionsof Clear Creek and Bouldercounties, Colorado,'byEdsonS. Bastinand...principalminingcentersare the following: Gilpin County ................................... ['Central...GILPIN COUNTY, COLORADO. 263 [Idaho Springs. /Gilson. -[Alice. [Dumont. Clear Creek County .........medium{I.Idaho Springs Mostly quartzt Moderately dynamo-meta- morphosed. cies. formation. Sedimentary |  | | Report (issue) | | Beryllium Area, Park and Jefferson t:-1 Counties, Colorado g ~ s:p ~ I> li:tl ~ GEOLOGICAL SURVEY PROFESSIONAL...Flats) Beryllium Area, Park and Jefferson Counties, Colorado By C. C. HAWLEY GEOLOGY AND ORE DEPOSITS OF THE...SOUTHERN TARRYALL REGION PARK AND JEFFERSON COUNTIES, COLORADO GEOLOGICAL SURVEY PROFESSIONAL PAPER 608-A A...rocks~ ____ ~ _______________________ _ Idaho Springs Formation ___________________ _ Amphibolite and hornblendite...hornblendite _______________ _ Boulder Creek{?) Granodiorite ______________ _ Silver Plume(?) Granite |  | | Report (issue) | | Some High-Grade Cordierite Gneisses, Front Range, Colorado Dolores J. Gable U.S. Geological Survey, Denver...SOCIETY OF AMERICA, INC. Colorado Building P.O. Box 1719 Boulder, Colorado 80302 Printed in the United...65 65 66 67 ... Vlll CORDIERITE GNEISSES, COLORADO FRONT RANGE Factors determining the mineral assen1blages...75 77 81 85 FIGURES l. Map of Front Range, Colorado ............... ................. .......... ...cordierite-bearing rocks in central part of Front Range, Colorado ................................. ....... ... |  | | Report (volume) | | urn-bearing Area, Ralston Buttes District, Jefferson County, Colorado U.S. GEOLOGICAL SURVEY BULLETIN 1555 Summary...urn-bearing Area, Ralston Buttes District, Jefferson County, Colorado By E.]. YOUNG U.S . GEOLOGICAL SURVEY BULLETIN...and prospects in the Front Range near Golden, Colorado UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON...uraniumbearing area, Ralston Buttes district, Jefferson County, Colorado. (Geological Survey bulletin ; 1555) Bibliography:...I. Geology-Colorado-Jefferson County. 2. Uranium mines and mining-Colorado-Jefferson County. 3. Geoch |  | | Journal (article/letter/editorial) | | District LARIMER COUNTY, COLORADO MARK I. JACOBSON 1350 E . Easter Avenue Littleton, Colorado 80122 B L U...This is one of the few pegmatite districts in Colorado where nei ther all the pegmatites have been studied...of the Crystal Mountain district, Larimer County, Colorado. Location The Crystal Mountain district is...Collins and Loveland within the Front Range of Colorado. Most of the district's pegmatites are found north...the Big Thomp son Canyon and south of Buckhorn Creek. This area can be located on the Crystal Mountain |
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