 | | 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) | | 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) | | 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 (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) | | 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 |  | | 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...tentatively identified as sillimanite." Pods of coarse-grained magnetite-quartz-sillimanite rock, as much as 25...those which have been correIated with the Idaho Springs formation and closely associatedmigmatite. Cord.ierite:Sterrett...of the mine on the north bank of Thirty-one Mile Creek. The outcrop is about 500 feet east of the Copper |  | | 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 |  | | Report (issue) | | QlJADRANGLE (TOGETHER 'VITH THE EMPIRE DISTRICT) COLORADo· BY JOSIAH E. SPURR AND GEORGE H. GARREY WITH............................ ___ ... . Biotite-sillimanite schist ........................................................_.......... . Distribution in Colorado ................................................. . . . . . . . . . . . . . . . . . . . 97 Idaho Springs auriferous area. __ ............. _.. _. _....Boulder County.............. . . . . . . . . . . . ......... . ....... . 103 Ores in Gilpin County .... |  | | 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 |  | | 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...garnet, staurolite, andalusite, sillimanite-muscovite, and sillimanite-microcline zones have been recognized...extensive recrystallization. Granodiorite of Boulder Creek type and quartz diorite were emplaced during the |  | | 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 |  | | 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 |  | | 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 (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 (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 ................................. ....... ... |  | | 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) | | Empire Quadrangle Grand, Gilpin, and Clear Creek Counties ColOrado. By WILLIAM A. BRADDOCK .,..,., GEOLOGICAL...diorite of St. Marys Lake__________________ Bo.ulder Creek Granite__________________________ Quartz diorite...in the Empire quadrangle, Grand, Gilpin, and Clear Creek Counties, Colo __ In pocket 3. Foliation and...plagioclase, quartz, and microcline in the Boulder Creek Granite_________________________ Triangular plot..._________________ Modal compoEition of Boulder Creek Granite___________________________________________________________ |  | | Journal (article/letter/editorial) | | Geological Survey, Vermillion, S. D. Paleozoic Colorado land mass extended from northern Black Hills nearly...transgression lasting to mid-Turonian (embracing Graneros formation). Basin downwarping recurred during Laramide and...across South Dakota. Wisconsin glaciation and formation of Missouri River are later than the old age valleys...west-north-west of Rapid City, and in other places. Rapid Creek, with well-developed intrenched meanders, is cut...State Geological Survey, Vermittion, S. D. A formation of chert and volcanic ash crops out east of Sioux |  | | 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 |  | | 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 |  | | Report (issue) | | Crystalline Rocks, Park and Jefferson Counties, Colorado GEOLOGICAL SURVEY PROFESSIONAL PAPER 608-B General...Crystalline Rocks, Park and Jefferson Counties, Colorado By C. C. HAWLEY and R. A. WOBUS GEOLOGY AND ORE...TARRYALL REGION, PARK AND JEFFERSON COUNTIES, COLORADO GEOLOGICAL SURVEY PROFESSIONAL PAPER 608-B...Tarryall region, Park and Jefferson Counties, Colorado) (Geological Survey Professional Paper 608-B)...Stratigraphic Pre-Cambrian. 2. Geology-Colorado Park Co. 3. Geology Colorado Jefferson Co. 4. GraniteColorado |  | | Report (issue) | | Washington Zinc ore, Friedensville, Pa. Banded iron-formation, Palmer, Mich. 6. Ribbon asbestos ore, Quebec...Peninsula, Mich. 10. Porphyry molybdenum ore, Colorado 11. Zinc ore, Edwards, N.Y. 12. Manganese nodules... Poncha Springs, Colo. 14. Tungsten ore, North Carolina Rutile in Precambrian Sillimanite-Quartz Gneiss...Gneiss and Related Rocks, East-Central Front Range, Colorado By SHERMAN P. MARSH and DOU1GLAS M. SHERIDAN GEOLOGY...and geochemical study of rutile-bearing rocks in Colorado and a description of their occurrence elsewhere |  | | 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 |
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