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Geologic Map of the Central San Juan Caldera Cluster, Southwestern Colorado by Peter W
Geologic Map of the Central San Juan Caldera Cluster, Southwestern Colorado By Peter W. Lipman Pamphlet to accompany Geologic Investigations Series I–2799 dacite Ceobolla Creek Tuff Nelson Mountain Tuff, rhyolite Rat Creek Tuff, dacite Cebolla Creek Tuff Rat Creek Tuff, rhyolite Wheeler Geologic Monument (Half Moon Pass quadrangle) provides exceptional exposures of three outflow tuff sheets erupted from the San Luis caldera complex. Lowest sheet is Rat Creek Tuff, which is nonwelded throughout but grades upward from light-tan rhyolite (~74% SiO2) into pale brown dacite (~66% SiO2) that contains sparse dark-brown andesitic scoria. Distinctive hornblende-rich middle Cebolla Creek Tuff contains basal surge beds, overlain by vitrophyre of uniform mafic dacite that becomes less welded upward. Uppermost Nelson Mountain Tuff consists of nonwelded to weakly welded, crystal-poor rhyolite, which grades upward to a densely welded caprock of crystal-rich dacite (~68% SiO2). White arrows show contacts between outflow units. 2006 U.S. Department of the Interior U.S. Geological Survey CONTENTS Geologic setting . 1 Volcanism . 1 Structure . 2 Methods of study . 3 Description of map units . 4 Surficial deposits . 4 Glacial deposits . 4 Postcaldera volcanic rocks . 4 Hinsdale Formation . 4 Los Pinos Formation . 5 Oligocene volcanic rocks . 5 Rocks of the Creede Caldera cycle . 5 Creede Formation . 5 Fisher Dacite . 5 Snowshoe Mountain Tuff . 6 Rocks of the San Luis caldera complex . 7 Rocks of the Nelson Mountain caldera cycle . 7 Rocks of the Cebolla Creek caldera cycle . 9 Rocks of the Rat Creek caldera cycle . 10 Lava flows premonitory(?) to San Luis caldera complex . .11 Rocks of the South River caldera cycle . -
General Disclaimer One Or More of the Following Statements May Affect
General Disclaimer One or more of the Following Statements may affect this Document This document has been reproduced from the best copy furnished by the organizational source. It is being released in the interest of making available as much information as possible. This document may contain data, which exceeds the sheet parameters. It was furnished in this condition by the organizational source and is the best copy available. This document may contain tone-on-tone or color graphs, charts and/or pictures, which have been reproduced in black and white. This document is paginated as submitted by the original source. Portions of this document are not fully legible due to the historical nature of some of the material. However, it is the best reproduction available from the original submission. Produced by the NASA Center for Aerospace Information (CASI) I Acv j ..a °" "^ i^e!<►)e ^r^}er Rim ^^^ the 1Q*re*t of wly arel w* d ►s- ,9*W,Ratieie of Wh Reaouries Survey ProgMM iobrmaiion and without liability ^CH00 #or Mry M Fade o thereof," ^ atK , !t4 O 'er E7.6- 1 0.1 9.9. s. z \IS74 GEOLOGIC INTERPRETATION OF SKYLAB PHOTOGRAPHS by Keenan Lee and Robert J. Weimer Remote Sensing Report 75-6 EREP Investigations 380 Contract NAS9-13394 National Aeronautics and Space Administration 8618 ON OF N /b-1 (E76 - 10199) GEOLOGIC INTERPRETATI SKYLAB PHOTOGRAPHS (Cclorado School CSCL 086 Mines) 85 p HC $5.00 Unclas G3/43 00199 December 1975 044: G: O ^d ci b C!] r4y ^ ^ x Frontispiece. View eastward from Island in the Sky area of Canyonlands National Park, across the canyon of the Colorado River, to the La Sal Mountains. -
(2000), Voluminous Lava-Like Precursor to a Major Ash-Flow
Journal of Volcanology and Geothermal Research 98 (2000) 153–171 www.elsevier.nl/locate/jvolgeores Voluminous lava-like precursor to a major ash-flow tuff: low-column pyroclastic eruption of the Pagosa Peak Dacite, San Juan volcanic field, Colorado O. Bachmanna,*, M.A. Dungana, P.W. Lipmanb aSection des Sciences de la Terre de l’Universite´ de Gene`ve, 13, Rue des Maraıˆchers, 1211 Geneva 4, Switzerland bUS Geological Survey, 345 Middlefield Rd, Menlo Park, CA, USA Received 26 May 1999; received in revised form 8 November 1999; accepted 8 November 1999 Abstract The Pagosa Peak Dacite is an unusual pyroclastic deposit that immediately predated eruption of the enormous Fish Canyon Tuff (ϳ5000 km3) from the La Garita caldera at 28 Ma. The Pagosa Peak Dacite is thick (to 1 km), voluminous (Ͼ200 km3), and has a high aspect ratio (1:50) similar to those of silicic lava flows. It contains a high proportion (40–60%) of juvenile clasts (to 3–4 m) emplaced as viscous magma that was less vesiculated than typical pumice. Accidental lithic fragments are absent above the basal 5–10% of the unit. Thick densely welded proximal deposits flowed rheomorphically due to gravitational spreading, despite the very high viscosity of the crystal-rich magma, resulting in a macroscopic appearance similar to flow- layered silicic lava. Although it is a separate depositional unit, the Pagosa Peak Dacite is indistinguishable from the overlying Fish Canyon Tuff in bulk-rock chemistry, phenocryst compositions, and 40Ar/39Ar age. The unusual characteristics of this deposit are interpreted as consequences of eruption by low-column pyroclastic fountaining and lateral transport as dense, poorly inflated pyroclastic flows. -
Ignimbrites to Batholiths Ignimbrites to Batholiths: Integrating Perspectives from Geological, Geophysical, and Geochronological Data
Ignimbrites to batholiths Ignimbrites to batholiths: Integrating perspectives from geological, geophysical, and geochronological data Peter W. Lipman1,* and Olivier Bachmann2 1U.S. Geological Survey, Mail Stop 910, Menlo Park, California 94028, USA 2Institute of Geochemistry and Petrology, ETH Zurich, CH-8092 Zürich, Switzerland ABSTRACT related intrusions cooled and solidified soon shorter. Magma-supply estimates (from ages after zircon crystallization, as magma sup- and volcano-plutonic volumes) yield focused Multistage histories of incremental accu- ply waned. Some researchers interpret these intrusion-assembly rates sufficient to gener- mulation, fractionation, and solidification results as recording pluton assembly in small ate ignimbrite-scale volumes of eruptible during construction of large subvolcanic increments that crystallized rapidly, leading magma, based on published thermal models. magma bodies that remained sufficiently to temporal disconnects between ignimbrite Mid-Tertiary processes of batholith assembly liquid to erupt are recorded by Tertiary eruption and intrusion growth. Alternatively, associated with the SRMVF caused drastic ignimbrites, source calderas, and granitoid crystallization ages of the granitic rocks chemical and physical reconstruction of the intrusions associated with large gravity lows are here inferred to record late solidifica- entire lithosphere, probably accompanied by at the Southern Rocky Mountain volcanic tion, after protracted open-system evolution asthenospheric input. field (SRMVF). Geophysical -
40Ar/39Ar Dating of the Late Cretaceous Jonathan Gaylor
40Ar/39Ar Dating of the Late Cretaceous Jonathan Gaylor To cite this version: Jonathan Gaylor. 40Ar/39Ar Dating of the Late Cretaceous. Earth Sciences. Université Paris Sud - Paris XI, 2013. English. NNT : 2013PA112124. tel-01017165 HAL Id: tel-01017165 https://tel.archives-ouvertes.fr/tel-01017165 Submitted on 2 Jul 2014 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Université Paris Sud 11 UFR des Sciences d’Orsay École Doctorale 534 MIPEGE, Laboratoire IDES Sciences de la Terre 40Ar/39Ar Dating of the Late Cretaceous Thèse de Doctorat Présentée et soutenue publiquement par Jonathan GAYLOR Le 11 juillet 2013 devant le jury compose de: Directeur de thèse: Xavier Quidelleur, Professeur, Université Paris Sud (France) Rapporteurs: Sarah Sherlock, Senoir Researcher, Open University (Grande-Bretagne) Bruno Galbrun, DR CNRS, Université Pierre et Marie Curie (France) Examinateurs: Klaudia Kuiper, Researcher, Vrije Universiteit Amsterdam (Pays-Bas) Maurice Pagel, Professeur, Université Paris Sud (France) - 2 - - 3 - Acknowledgements I would like to begin by thanking my supervisor Xavier Quidelleur without whom I would not have finished, with special thanks on the endless encouragement and patience, all the way through my PhD! Thank you all at GTSnext, especially to the directors Klaudia Kuiper, Jan Wijbrans and Frits Hilgen for creating such a great project. -
2016 Castle Valley Water Study Report Part 1
HYDROLOGIC ASSESSMENT OF THE SURFACE WATER AND GROUNDWATER RESOURCES OF CASTLE VALLEY, UTAH: PART 1: HYDROLOGIC AND ENVIRONMENTAL ANALYSIS (HESA) AND PRELIMINARY WATER BUDGET Authors: Dr. Kenneth E. Kolm, Hydrologic Systems Analysis, LLC., Golden, Colorado and Paul K.M. van der Heijde, Heath Hydrology, Inc., Boulder, Colorado Prepared For: Town of Castle Valley, Utah March 2016 Front Page: Town of Castle Valley, Utah (November 2013) Table of Contents 1. INTRODUCTION ………………………………………………………………………... 1 2. DEVELOPMENT OF A CONCEPTUAL MODEL OF HYDROLOGIC SYSTEMS OF THE CASTLE VALLEY (TCV) STUDY AREA ……………………..…………………….. 3 2.1 Climate ………………………………………………………………………….... 3 2.2 Topography and Geomorphology ………………………………………………... 6 2.3 Surface Water Characteristics and Springs ………………………………………. 9 2.4 Hydrogeologic Framework ………………………………………………………. 16 2.4.1 Regional Hydrogeologic Units ………………………………………… 17 2.4.2 Hydrogeologic Units of the TCV Area..…………………….………….. 20 2.4.3 Hydro-structural Units of the TCV Area ………………………………. 24 2.5 Groundwater Flow Systems …………………………………………………….... 28 2.6 Groundwater System Conceptual Site Models by Subsystem …….………….….. 31 2.6.1 La Sal Mountain Subsystems …………………………………………... 32 2.6.2 Hillslope and Valley Bottom Shallow Aquifer Subsystems ………….... 37 2.7 Anthropogenic Influences ……………………………………………………….. 40 2.7.1 Effects of Land Use Changes on Groundwater Systems …………….… 40 2.7.2 Potential Effects of Groundwater Use on Water Quality ……………… 42 2.7.2.1 Hillslope Subsystems Water Quality ………………………... 43 2.7.2.2 Valley Bottom -
Climbs and Expeditions, 1988
Climbs and Expeditions, 1988 The Editorial Board expresses its deep gratitude to the many people who have done so much to make this section possible. We cannot list them all here, but we should like to give particular thanks to the following: Kamal K. Guha, Harish Kapadia, Soli S. Mehta, H.C. Sarin, P.C. Katoch, Zafarullah Siddiqui, Josef Nyka, Tsunemichi Ikeda, Trevor Braham, Renato More, Mirella Tenderini. Cesar Morales Arnao, Vojslav Arko, Franci Savenc, Paul Nunn, Do@ Rotovnik, Jose Manuel Anglada, Jordi Pons, Josep Paytubi, Elmar Landes, Robert Renzler, Sadao Tambe, Annie Bertholet, Fridebert Widder, Silvia Metzeltin Buscaini. Luciano Ghigo, Zhou Zheng. Ying Dao Shui, Karchung Wangchuk, Lloyd Freese, Tom Elliot, Robert Seibert, and Colin Monteath. METERS TO FEET Unfortunately the American public seems still to be resisting the change from feet to meters. To assist readers from the more enlightened countries, where meters are universally used, we give the following conversion chart: meters feet meters feet meters feet meters feet 3300 10,827 4700 15,420 6100 20,013 7500 24,607 3400 11,155 4800 15,748 6200 20,342 7600 24,935 3500 11,483 4900 16,076 6300 20,670 7700 25,263 3600 11,811 5000 16,404 6400 20,998 7800 25,591 3700 12,139 5100 16,733 6500 21,326 7900 25,919 3800 12,467 5200 17.061 6600 21,654 8000 26,247 3900 12,795 5300 7,389 6700 21,982 8100 26,575 4000 13,124 5400 17,717 6800 22,3 10 8200 26,903 4100 13,452 5500 8,045 6900 22,638 8300 27,231 4200 13,780 5600 8,373 7000 22,966 8400 27,560 4300 14,108 5700 8,701 7100 23,294 8500 27,888 4400 14,436 5800 19,029 7200 23,622 8600 28,216 4500 14,764 5900 9,357 7300 23,951 8700 28,544 4600 15,092 6000 19,685 7400 24,279 8800 28,872 NOTE: All dates in this section refer to 1988 unless otherwise stated. -
Geophysical Study of the San Juan Mountains Batholith Complex, Southwestern Colorado
Geophysical study of the San Juan Mountains batholith complex, southwestern Colorado Benjamin J. Drenth1,*, G. Randy Keller1, and Ren A. Thompson2 1ConocoPhillips School of Geology and Geophysics, 100 E. Boyd Street, University of Oklahoma, Norman, Oklahoma 73019, USA 2U.S. Geological Survey, MS 980, Federal Center, Denver, Colorado 80225, USA ABSTRACT contrast of the complex. Models show that coincident with the San Juan Mountains (Fig. 3). the thickness of the batholith complex var- This anomaly has been interpreted as the mani- One of the largest and most pronounced ies laterally to a signifi cant degree, with the festation of a low-density, upper crustal granitic gravity lows over North America is over the greatest thickness (~20 km) under the west- batholith complex that represents the plutonic rugged San Juan Mountains of southwest- ern SJVF, and lesser thicknesses (<10 km) roots of the SJVF (Plouff and Pakiser , 1972). ern Colorado (USA). The mountain range is under the eastern SJVF. The largest group of Whereas this interpretation remains essentially coincident with the San Juan volcanic fi eld nested calderas on the surface of the SJVF, unchallenged, new gravity data processing tech- (SJVF), the largest erosional remnant of a the central caldera cluster, is not correlated niques, digital elevation data, and constraints widespread mid-Cenozoic volcanic fi eld that with the thickest part of the batholith com- from seismic refraction studies (Prodehl and spanned much of the southern Rocky Moun- plex. This result is consistent with petrologic Pakiser , 1980) enable reassessment and improve- tains. A buried, low-density silicic batholith interpretations from recent studies that the ment of the previous model. -
Adventures Guide to Plan Your Custom Day of Of-Roading
“WILDERNESS IS NOT A LUXURY, BUT A NECESSITY OF THE HUMAN SPIRIT” - EDWARD ABBEY Dear Valued Guest, Welcome to Sorrel River Ranch Resort & Spa! During your visit we invite you to immerse yourself in the many bucket-list (or awe-inspiring) adventures available in this scenic land of arches, rivers, canyons, and mesas. Explore the surrounding areas with our knowledgeable guides by foot, horseback, air or water. Upon returning to the Ranch indulge yourself in a Signature Spa Treatment, a fresh garden-to-table meal and relaxing and reflective storytelling around the riverside campfire Our experienced adventure team will help curate custom adventure experiences that will expose you to the best that the Ranch and Moab have to ofer. We encourage you to get out of your comfort zone, discover the incredible secrets of the American Southwest, and allow us to create a customized itinerary for an unforgettable journey of exploration and exclusivity. Elizabeth Rad Owner, Elizabeth Rad Sorrel Sorrel River Ranch Resort & Spa Exclusive TABLE OF CONTENTS Horseback Riding.................................4-15 Guided Hiking & Driving Tours.............................................16-21 UTV Tours...................................................22-21 Jeep Tours..............................................24-25 Canyoneering, Rockaneering, & Climbing..............................................26-29 Mountain Biking.................................30-33 Kayaking & SUP..................................34-35 River Rafting..........................................36-37 -
Penitente Canyon and Elephant Rock
Penitente Canyon and Elephant Rock Introduction: rocks resulting from this eruption were unusually uniform in composition. This would imply that the ash cooled as a single unit. This Penitente Canyon unit is known as the Fish Canyon Tuff. Many The canyon itself is part of the La Garita sections of the Fish Canyon Tuff are over 4,000 Caldera, a volcanic eruption that occurred in the feet thick. The area at Elephant Rocks is mainly San Juan Mountains about 26-28 million years grassland with scattered massive boulders laid ago. It is said to be the largest known explosive out. It is also habitat to the rock loving eruption in the Earth’s history, sending ash as far Neoparrya, which flourishes in igneous outcrops off as the U.S. Eastern Seaboard. The resulting or sedimentary rocks from volcanic eruptions. deposit is called Fish Canyon Tuff, which is The Neoparrya is native to the San Luis Valley volcanic ash molded together, according to and is known to exist only here and in the Wet Colville. The resulting geological formations are Mountain Valley regions. The Fish Canyon Tuff ideal for the sport of rock climbing. makes up the Elephant Rocks and gradually The La Garita Mountains are a sub-range of erodes over time to provide the proper soil the San Juans in southwest Colorado and chemistry and growth conditions in order for comprising parts of the Rio Grande and the this plant to thrive. The recreation area is 378 Gunnison National Forests. This lesser known acres with an elevation of 7,900 feet managed wilderness area in Colorado is actually one by the Bureau of Land Management. -
2017 Briefing Book Colorado Table of Contents Colorado Facts
U.S. Department of the Interior Bureau of Land Management 2017 Briefing Book Colorado Table of Contents Colorado Facts .......................................................................................................................................................................................... 1 Colorado Economic Contributions ..................................................................................................................................................... 2 History .................................................................................................................................................................................................. 3 Organizational Chart ........................................................................................................................................................................... 4 Branch Chiefs & Program Leads ........................................................................................................................................................ 5 Office Map ............................................................................................................................................................................................ 6 Colorado State Office ................................................................................................................................................................................ 7 Leadership ......................................................................................................................................................................................... -
Pollen Evidence of Floristic Turnover Forced by Cool Aridity During the Oligocene in Colorado GEOSPHERE; V
Research Paper GEOSPHERE Pollen evidence of floristic turnover forced by cool aridity during the Oligocene in Colorado GEOSPHERE; v. 15, no. 1 Estella B. Leopold and Stephanie Zaborac-Reed University of Washington, Department of Biology, Box 351800, Seattle, Washington 98195, USA https://doi.org/10.1130/GES01689.1 7 figures; 6 plates; 11 tables; ABSTRACT Manchester, 1997). In Colorado, the EOT is associated with a period of cooling 1 set of supplemental files and severe aridity lasting most of the Oligocene. One of our strongest contri- New pollen data from four Oligocene floras in volcanic landscapes of Colo butions is the addition of the pollen record from four Oligocene floras, which CORRESPONDENCE: eleopold@ uw.edu rado record important climatic shifts that reshaped the local flora and promoted had not been reported previously. This pollen record is an important aspect the development of subarid vegetation types. We combined new pollen data of this paper for assessing the total flora. The emphasis of this study is on the CITATION: Leopold, E.B., and Zaborac-Reed, S., 2019, Pollen evidence of floristic turnover forced by with previous megafossil evidence to assess vegetation changes during the evolutionary and climatic significance of the floristic changes during the EOT. cool aridity during the Oligocene in Colorado: Geo- Eocene–Oligocene Transition (EOT). Pollen data are the basis for updating Five Colorado floras of late Eocene through Oligocene age lie within the sphere, v. 15, no. 1, p. 254–294, https:// doi .org /10 the list of flora identified at Creede. Local extinctions in response to lower sum geographic mix of caldera and volcanic settings in the central Colorado vol- .1130 /GES01689.1.