| | Journal (article/letter/editorial) | Photomicrographs of representative ) basalts of the San Luis Valley area . 1 Plate 2. Photomicrographs of...northern end of the depression, in the vicinity of the San Luis Valley (Fig. 1), where I have worked and where...on problems of basalts of the southern Rocky Mountains and for permission to use unpublished chemical...each bounded on one or both sides by fault-block mountains (Kelley, 1952, 1956). On a regional scale this...and extends northward into the southern Rocky Mountains at least as far as central Colorado (Fig. 1). | | | Report (issue) | SURVEY A digital geologic map and explanation of the San Antonio Mountain quadrangle, Rio Arriba and Taos...Taylor, 1992) for a digital geologic map of the San Antonio Mountain quadrangle, Rio Arriba and Taos...The two units are only distinguished in fie Rio San Antonio drainage. Age estimates and correlations...slightly undulating, flood plains along the Rio San Antonio. Depositional surface typically 1 to 3 meters...Pleistocene) ~ Poorly sorted detritus on the slopes of San Antonio Mountain, size ranges from silt to boulders | | | Journal (article/letter/editorial) | Colorado 8022) Volcanic History of the San Juan Mountains, Colorado, as Indicated by Potassium-Argon...Potassium-Argon Dating ABSTRACT Volcanic rocks in the San Juan Mountains constitute the largest erosional remnant...that extended over much of the southern Rocky Mountains and adjacent areas in Oligocene and later time...the gross petrologic evolution throughout the San Juan remnant of this field was relatively simple, with...original field indicate a similar evolution. In the San Juan field, voluminous early lavas and breccias—mainly | | | Report (issue) | The two units are only distinguished in the Rio San Antonio drainage. Age estimates and correlations...Pleistocene) ~ Poorly sorted detritus on the slopes of San Antonio Mountain, size ranges from silt to boulders...units that were deposited during extension in the San Luis basin and uplift of its western flank. The map...area comprises part of the western boundary of the San Luis basin, a shallow dip slope of eastward-tilted...and sedimentary rocks of the southern San Juan and Tusas Mountains. The Oligocene and Miocene units exposed | | | Report (issue) | volcanic rocks that were eroded from the San Juan Mountains (Steven and others, 1974), about 9 km west...Sparse small olivine phenocrysts partly altered to iddingsite are typical, weakly developed diktytaxitic groundmass...Mehnert, unpub. data, 1992) and to the east in the San Luis Hills (Thompson and others, 1991). Thickness...lower Conejos River canyon area, southeastern San Juan Mountains, Colorado: U.S. Geological Survey Miscellaneous...southern Rocky Mountains, in Curtis, B.F., ed., Cenozoic history of the southern Rocky Mountains: Geological | | | Report (issue) | Related Volcanic Rocks, Southeastern SanJuan Mountains, Colorado GEOLOGICAL SURVEY PROFESSIONAL PAPER...and Related Volcanic Rocks, Southeastern San Juan Mountains, Colorado By PETER W. LIPMAN GEOLOGICAL...and related volcanic rocks, southeastern San Juan Mountains, Colorado. (Geological Survey Professional...16:852 1. Volcanism-San Juan Mountains. 2. Volcanic ash, tuff, etc.-San Juan Mountains. I. Title. II. Series:.... . . . . . . . . . . . . . . . . . . . . . . San Juan caldera cluster . . . . . . . . . . . . . . . | | | Report (issue) | volcano. A 25-m.y. ash-flow tuff in the Harcuvar Mountains, 30 km south of McLendon volcano, may have come...Tuff Artillery Mountains Anderson Mine Mogollon-Datil volcanic field Vulture Mountains Harquavar Mtns...has cloaked the olivine with an exterior rim of iddingsite and a serpentine-like mineral stained with hematite...and cracks are present in the high-Mg olivine. Iddingsite occurs as an alteration product partially or...63.0 Phenocrysts (volume percent) microlites iddingsite antlgorite Clinopyroxene Oxyhornblende 47.0 | | | Journal (article/letter/editorial) | Petrology and geochemistry of the Huerto Andesite, San Juan volcanic field, Colorado Daniel R.R. Askren, James...Geology, University of Georgia, Athens, GA 30602, USA Received September 27, 1990 / Accepted October 9...interlayered with the large-volume ash-flow tuffs of the San Juan volcanic field, Colorado. Stratigraphically this...evolved lavas. Despite the great distance of the San Juan volcanic field from the inferred Oligocene destructive...recognized ash-flow calderas. Introduction The San Juan volcanic field of south-central Colorado covers | | | Journal (article/letter/editorial) | Institute of Technology, Pasadena, Calif. 91125 (USA} Received March 31, 1976 Revised version received...pheno of ol; with alteration to opaques, chl and iddingsite along cracks and margins; in a fg ophitic gdmass...fracture of the Silverton caldera, western San Juan Mountains .[2]. The plutonic igneous rocks of central...igneous intrusions, with particular reference to the San Juan volcanic field, Colorado, in: Geochemical Transport | | Collins, Donley S., Cobban, Robert R., Foord, Eugene E., Murphy, Jack A. (1989) Bibliography for update and revision of U.S.G.S. Bulletin 1114, Minerals of Colorado -- a 100 year record, by Edwin B. Eckel, Part A - Paper copy --Bibliography data file disks. Open-File Report Vol. 1989 (89-206) US Geological Survey doi:10.3133/ofr89206a | Report (issue) | W. E., 1900, Report on the Alta group of mines, San Miguel County, Colorado: Golden, Colorado School...Armbrustmacher, T. J., 1976, Thorium deposits in the Wet Mountains area, Fremont and Custer Counties, Colorado: U...and primary magmatic carbonatites from the Wet Mountains area, Fremont and Custer Counties, Colorado: Economic...Multipleintruded carbonatite dike in the Wet Mountains of Colorado, in Geological Survey research 1978:...Multiple carbonatite dike at McClure Gulch, Wet Mountains alkalic province, Fremont County, Colorado: The | | | Report (issue) | the Rio Grande from north of Weminuche meadows, San Cristobal quadrangle. The upper cliff-forming flow...Alboroto rhyolite. Geology and Petrology of the San Juan Region Southwestern Colorado By ESPER S. LARSEN...OF THE WORK A study of the geology of the San Juan Mountains was begun by Whitman Cross in 1895. The project...following table. Early work in the western San Juan Mountains Quadrangle Field work Workers La Plata (folio...Clements, O. W. Stose, and R. .D. George. Ncocllo Mountains 1900,1901- Whitman Cross and Ernest (folio 131) | | | Report (issue) | Deposits of the Eureka and Adjoining Districts San Juan Mountains, Colorado By WILBUR S. BURBANK and ROBERT...Development Board A study of part of the western San Juan Mountains eruptive center, its related cauldron subsidence...Tertiary volcanic rocks_- ___ - ___________________ _ San Juan Formation ________________ -------Silverton Volcanic...Silverton cauldron and areas nearby in Ouray, San Juan, San Miguel, and Hinsdale Counties. 2. Geologic...sections of the Eureka district and adjoining areas, San Juan, Ouray, and Hinsdale Counties, and explanation | | | Report (volume) | Boulder County to the southern limits of the San Juan Mountains. They have yielded much of the silver and...minerals in the lava flows of North and South Table Mountains, lefferson County, the contact-metamorphic minerals... LOCALITIES 17 Arkansas River and Ruby and Sugarloaf Mountains east of the river-yield gem crystals from lithophysae...Cement Creek on a poor secondary road. The Italian Mountains are about 1 miles northeast of (and 2,000 feet...one-half mile to the mine. Locality 18.-Table Mountains. Analcite, apophyllite, aragonite, calcite, chabazite | | | Report (issue) | 3XT Cenozoic History of the Southern Rocky Mountains Digitized by the Internet Archive In 2022 with...Memoir 144 Cenozoic History of the Southern Rocky Mountains Papers deriving from a symposium presented at...Eocene erosion surface in the Southern Rocky Mountains a LS ob eta OM ROR een Er Rudy C. Epis and Charles...Tertiary volcanic field in the Southern Rocky Mountains ere ewe te en yang 9 Cur wid Me eat. dhe Thomas...the Rio Grande depression in the Southern Rocky Mountains Reiter Par ee sain As Peter W. Lipman and Harald | | | Journal (article/letter/editorial) | opaques. Olivine is partly or completely altered to iddingsite. 5. Geochemistry To determine the chemical characteristics...(2001): Exhumation of the west-central Alborz Mountains, Iran, Caspian subsidence, and collision-related...the Oligocene Conejos Formation, San Juan Mountains, Colorado, USA. – J. of Volcanol. and Geotherm. Res | | | Report (issue) | BATHOLITH AND ASSOCIATED ROCKS OF CORONA, ELSINORE, AND SAN LUIS REY QUADRANGLES SOUTHERN CALIFORNIA BY ESPER.... . . . . . . . . . . . . . . . . . . . . . . . San Luis Rey quadrangle . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . Santa Ana Mountains.................................... . ..........25 25 27 27 27 28 . Vl CONTENTS So:.i th of San Marcos. . . . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . . San Marcos gab bro . . . . . . . . . . . . . . . . . | | | Journal (article/letter/editorial) | petrographitally except for development of some iddingsite on olivine. Partitioning of Ce+4 into either...other major ignimbrite fields such as the San Juan Mountains (Lipman et al., 1978) there is isotopic evidence...Sierra Madre Occidental may be analogous to the San Juan volcanic field of Colorado where the ignimbrites...Steven T. A. (1978) Petrologic evolution of the San Juan volcanic field, southwestern Colorado: Pb and...Trace-element variations at Summer Coon volcano, San Juan Mountains, Colorado, and the origin of continental-interior | | | Report (volume) | formation________________________________________ San Juan breccia_______________________-_____________-____...resurvey of the mineralized region of the San Juan Mountains. The youthful topography, with a total relief...that followed several periods of uplift of the San Juan peneplain, with repeated glaciations that formed...As this area is on the west flank of the great San Juan volcanic pile, west of the Silverton caldera,...the volcanic units recognized farther east; the San Juan breccia, Eureka rhyolite, Burns latite, and Potosi | | | Thesis/Dissertation | elevated region which is generally known as the San Juan Mountains. Creede is situated on 77illow the Rio Grande...over 3300 feet. Only a few miles to the north is San Luis Peak, which is over fourteen thousand feet in...dV > Lise most of the mountainous area of the San Juan, the region is tim- bered and well watered. ...district is more accessible than many camps of the San Juan and rates for shipping ore are considerably lower...Bibliography. On the geology and ore deposits of the San Juan there is an extensive Lists of the publications | | | Journal (article/letter/editorial) | study in southwestern lqevada and in the San Juan Mountains, Colorado, and probably are widespread in...Weak deutcrie or secondary alteration to a brown iddingsite-like material has occurred around the edges of...author in southwestern Nevada and in the San Juan Mountains, Colorado, bulk-rock compositions deviate | | | Journal (article/letter/editorial) | Pacific Rise (EPR) (Thompson et al., 1989), and Juan de Fuca Rise of the Pacific Ocean basin (Van Wagoner...vesicles do not contain secondary minerals, but iddingsite rims around olivine are noted in thin section...alteration because only some samples have even thin iddingsite rims on olivine phenocrysts, most samples have...Surtsey Islands) (Furman et al., 1991); Floreana, San Cristobal, and Santa Cruz Islands (White et al.,...between a MORB source and the Kerguelen plume. as San Cristobal and Floreana Islands (Fig. 4A), which have | | | Report (volume) | Sangre de Cristo Mountains, in Guidebook of the southeastern Sangre de Cristo Mountains, New Mexico: New...Isostatic compensation in the Sangre de Cristo Mountains, New Mexico: U.S. Geol. Survey Prof. Paper 424-D...Atkinson, W. W., Jr., 1960, Geology of the San Pedro Mountains, Santa Fe County, New Mexico: New Mexico...S. thesis, 81 p. ---1961, Geology ofthe San Pedro Mountains, Santa Fe County, New Mexico: New Mexico...---1976, Zoning and paragenesis of ores in the San Pedro Mountains, Santa Fe County, New Mexico, in Tectonics | | | Report (issue) | - _ ___ Age of volcanic activity in the San Juan Mountains, Colo., by T. A. Steven, H. H. Mehnert, and..._____ ----_ Ordovician tectonism in the Ruby Mountains, Elko County,· Nev., by Ronald Willden and R...._______ Usc of infrared imagery in study of the San Andreas fault system, California, by R. E. Wallace...metals and silver in the southern Santa Rita Mountains, Santa Cruz County, Ariz., by Harald Drewes--...ck streams on Mount Mestas, Sangre de Cristo Mountains, southern Colorado, by R. B. Johnson_________________ | | | Report (issue) | Most crystals have a thin orange brown rim of iddingsite, and many contain small chrome spinel inclusions...typically are slightly resorbed and rimmed by iddingsite, and they may contain chrome spinel inclusions...others (1969) on basalt of the southern Rocky Mountains. These authors document contamination of basalt...(1970); field for Pliocene andesite of the Lava Mountains, Calif, from Smith (1964); Cascade Range trend...described from the San Juan volcanic field in southwestern Colorado. The San Juan andesite has REE patterns | | | Report (issue) | Similarity of Cenozoic igneous activity in the San Juan and Elk Mountains, Colo., and its regional significance...Nizina Limestones of part of the southern Wrangell Mountains, Alaska A preliminary report stressing carbonate...Aleutian Islands (Coats, 1950) and the Wrangell Mountains (fig. 1). The Mount Edgecumbe volcanic field is...P-Pribilof Islands B-Buldir U - Umnak W-Wrangell Mountains K-Katmai E-Mt. Edgecumbe, Kruzof Island ED-EdzizaPeak...Probably this late product is "bowlingite" or "iddingsite." Chlorophaeite present in a few specimens is |
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