DOCSLIB.ORG

An Ignimbrite Caldera from the Bottom Up: Exhumed Floor and Fill of the Resurgent Bonanza Caldera, Southern Rocky Mountain Volcanic GEOSPHERE; V

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
An Ignimbrite Caldera from the Bottom Up: Exhumed Floor and Fill of the Resurgent Bonanza Caldera, Southern Rocky Mountain Volcanic GEOSPHERE; V Research Paper GEOSPHERE An ignimbrite caldera from the bottom up: Exhumed floor and fill of the resurgent Bonanza caldera, Southern Rocky Mountain volcanic GEOSPHERE; v. 11, no. 6 field, Colorado doi:10.1130/GES01184.1 1 2 2 24 figures; 4 tables; 4 supplemental files Peter W. Lipman , Matthew J. Zimmerer , and William C. McIntosh 1U.S. Geological Survey, Menlo Park, California 94025, USA 2New Mexico Bureau of Geology and Mineral Resources, Socorro, New Mexico 87801, USA CORRESPONDENCE: [email protected] CITATION: Lipman, P.W., Zimmerer, M.J., and McIntosh, W.C., 2015, An ignimbrite caldera from the bottom up: Exhumed floor and fill of the resurgent ABSTRACT while tilting and deep erosion provide three-dimensional exposures of intra- Bonanza caldera, Southern Rocky Mountain vol canic caldera fill, floor, and resurgent structures. The absence of Plinian-fall deposits field, Colorado: Geosphere, v. 11, no. 6, p. 1902–1947, Among large ignimbrites, the Bonanza Tuff and its source caldera in the beneath proximal ignimbrites at Bonanza and other calderas in the region is doi:10 .1130 /GES01184.1. Southern Rocky Mountain volcanic field display diverse depositional and struc- interpreted as evidence for early initiation of pyroclastic flows, rather than lack tural features that provide special insights concerning eruptive processes and of a high eruption column. Although the absence of a Plinian deposit beneath Received 26 February 2015 Revision received 25 June 2015 caldera development. In contrast to the nested loci for successive ignimbrite some ignimbrites elsewhere has been interpreted to indicate that abrupt Accepted 14 August 2015 eruptions at many large multicyclic calderas elsewhere, Bonanza caldera is rapid foundering of the magma-body roof initiated the eruption, initial caldera Published online 2 October 2015 an areally isolated structure that formed in response to a single ignimbrite collapse began at Bonanza only after several hundred kilometers of rhyolitic eruption. The adjacent Marshall caldera, the nonresurgent lava-filled source tuff had erupted, as indicated by the minor volume of this composition in for the 33.9-Ma Thorn Ranch Tuff, is the immediate precursor for Bonanza, but the basal intracaldera ignimbrite. Caldera-filling ignimbrite has been largely projected structural boundaries of two calderas are largely or entirely separate stripped from the southern and eastern flank of the Bonanza dome, exposing even though the western topographic rim of Bonanza impinges on the older large areas of caldera-floor as a structurally coherent domed plate, bounded caldera. Bonanza, source of a compositionally complex regional ignimbrite by ring faults with locations that are geometrically closely constrained even sheet erupted at 33.12 ± 0.03 Ma, is a much larger caldera system than pre- though largely concealed beneath valley alluvium. The structurally coherent viously recognized. It is a subequant structure ~20 km in diameter that sub- floor at Bonanza contrasts with fault-disrupted floors at some well-exposed sided at least 3.5 km during explosive eruption of ~1000 km3 of magma, then multi cyclic calderas where successive ignimbrite eruptions caused recurrent resurgently domed its floor a similar distance vertically. Among its features: subsidence. Floor rocks at Bonanza are intensely brecciated within ~100 m (1) varied exposure levels of an intact caldera due to rugged present-day inboard of ring faults, probably due to compression and crushing of the sub- topog raphy—from Paleozoic and Precambrian basement rocks that are in- siding floor in proximity to steep inward-dipping faults. Upper levels of the truded by resurgent plutons, upward through precaldera volcanic floor, to floor are locally penetrated by dike-like crack fills of intracaldera ignimbrite, a single thickly ponded intracaldera ignimbrite (Bonanza Tuff), interleaved interpreted as dilatant fracture fills rather than ignimbrite vents. The resur- landslide breccia, and overlying postcollapse lavas; (2) large compositional gence geometry at Bonanza has implications for intra caldera-ignimbrite vol- gradients in the Bonanza ignimbrite (silicic andesite to rhyolite ignimbrite; ume; this parameter may have been overestimated at some young cal deras 60%–76% SiO2); (3) multiple alternations of mafic and silicic zones within a elsewhere, with bearing on outflow-intracaldera ratios and times of initial cal- single ignimbrite, rather than simple upward gradation to more mafic compo- dera collapse. Such features at Bonanza provide insights for interpreting cal- sitions; (4) compositional contrasts between outflow sectors of the ignimbrite deras universally, with respect to processes of caldera collapse and resurgence, (mainly crystal-poor rhyolite to east, crystal-rich dacite to west); (5) similarly inception of subsidence in relation to progression of the ignimbrite eruption, large compositional diversity among postcollapse caldera-fill lavas and resur- complications with characterizing structural versus topographic margins of cal- gent intrusions; (6) brief time span for the entire caldera cycle (33.12 to ca. deras, contrasts between intra- versus extracaldera ignimbrite, and limitations 33.03 Ma); (7) an exceptionally steep-sided resurgent dome, with dips of 40°– in assessing volumes of large caldera-forming eruptions. Bonanza provides a 50° on west and 70°–80° on northeast flanks. Some near-original caldera mor- rare site where intact caldera margins and floor are exhumed and exposed, For permission to copy, contact Copyright phology has been erosionally exhumed and remains defined by present-day providing valuable perspectives for understanding younger similar calderas in Permissions, GSA, or [email protected]. landforms (western topographic rim, resurgent core, and ring-fault valley), some of the world’s most active and dangerous silicic provinces. © 2015 Geological Society of America GEOSPHERE | Volume 11 | Number 6 Lipman et al. | An ignimbrite caldera from the bottom up Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/11/6/1902/4333789/1902.pdf 1902 by guest on 29 September 2021 Research Paper 108°W 106° 104° 40° N 060 mi INTRODUCTION 0100 km Denver F r The composite Southern Rocky Mountain volcanic field (SRMVF) (Fig. 1) N o n t has long been studied as a site of mid-Tertiary silicic volcanism on especially voluminous scales (Cross and Larsen, 1935; Larsen and Cross, 1956; Lipman R et al., 1970; Epis and Chapin, 1974; Steven and Lipman, 1976; McIntosh and a n WMT Chapin, 2004), including at least 28 ignimbrite sheets (each 150–5000 km3) and g S e l l South GP l a associated calderas active at 37–23 Ma (Tables 1 and 2). Ignimbrite-caldera sys- l w l l Park l l a t tems of the San Juan Mountains, constituting the largest preserved erosional c Colorado h BP 39-Mile Springs remnant of the SRMVF, have been a special focus for recent volcanologic and volcanic petrologic research: southeastern calderas (Platoro complex: Dungan et al., MP area MA 1989; Lipman et al., 1996), western (Uncompahgre-Silverton–Lake City: Hon Approx. original limit l West Elk l l and Lipman, 1989), and the central cluster (La Garita–Creede calderas: Lipman, of volcanic locusrocks R GunnisoGunnisonn g x e 2000, 2006; Bachmann et al., 2002, 2007). Much less examined have been Bo- Area of Fig. 2 nanza and adjacent Marshall calderas in the northeast San Juan region (Figs. M Bz l l l W l 2 and 3), which define a transition from earlier volcanism in central Colorado l l l l e C l l t l to the larger-volume younger ignimbrite-caldera foci farther southwest (Fig. 1). l NP l l S l l l l l l l l l l l l l l a l l l l l l l l M l Saguachex n Other than mineral-resource studies of small areas (e.g., Scott et al., 1975; Van l l Saguache l l l l l Structural l l l g t 38° l l l l s l l l l l r l SL l l LO boundary Alstine, 1975; Olson, 1988), most of the northeastern San Juan Mountains until l l LGn . l l e l l l l l l l l l SK l l l l San Luis l S l l B l l l l l recently had been examined only in reconnaissance for the Colorado State l l l l l ll l l l l l l l l l l SC l l l Cr geologic map (Tweto et al., 1976; Tweto, 1979). l San l l l l l l l Juan l Rio Grande rift l SR l Existence of a caldera has long been inferred in the Bonanza area, based on l l l l l l volcanic d l l l l Va e l l locus gravity data (Karig, 1965) and regional reconnaissance studies (Steven and Lip- lLGs l l l l l l l l l l l l ley segme l man, 1976; Varga and Smith, 1984), but detailed geologic mapping, petrologic Approx. l l l l l l Pl of volcanic rock l l l information, and geochronologic data have been sparse. The only previously Spanish published geologic maps for any part of Bonanza caldera were the pioneering o C riginal limi Peaks r report on the Bonanza mining district by Patton (1916) and a more detailed nt, i s Colorado t study of the district at a scale of 1:12,000 (Burbank, 1932). These studies dis- o New Mexico T tinguished the major local rock units for a relatively small area and provided u l l s t s l Questa-Latir information on mine workings, but both were undertaken before development a l s l volcanic of modern concepts for ignimbrite volcanism and associated caldera sub- M l l l l M locus t t s s sidence. Several theses at the Colorado School of Mines in the late 1960s and .
Load more

Recommended publications
  • 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 .
    [Show full text]
  • Tom Sharp's Post
    19 Tom Sharp's Post Tom Sharp's Post, a log and adobe Indian trading station, built in 1870, is a familiar sight to those traveling Highway 305, in Huerfano County, between the remnants of Malachite and the top of Pass Creek Pass. The post, flbout a mile from the site of the once-thriving town called Malachite, stands near the Huerfano River crossing of the Gardner-Red Wing. road. Sharp's place was known as Buzzard Roost Ranch be­ cause hundreds of buzzards roosted in the cottonwood trees along the stream there. A well-traveled Ute Indian trail over the Sangre de Cristo range ran through the ranch, thence to Badito, and on to the Greenhorn Mountains. Ute Chief Ouray and his wife, Chipeta, often visited Sharp while their tribes­ men camped nearby. W. T. (Tom) Sharp, a native of Missouri, served with the Confederate forces at the beginning of the Civil War. His general was Sterling Price. In 1861, Sharp was paroled from the service because of wounds, and was placed in a wagon bound for the Far West. Surviving the trip across country, he joined a half-breed Indian hunter named "Old Tex,'' and for a time the two sup­ plied meat to mining camps in California and Oregon . Later Sharp headed eastward. With a partner, John Miller, he contracted to supply telegraph poles for the Union Pacific Railroad, then building into Wyoming. In 1867, he was a de­ puty sheriff in Cheyenne, Wyoming. In the autumn of 1868, Tom Sharp, John White, and John Williams, with an old prairie wagon, came into the Huerfano Valley looking for a location.
    [Show full text]
  • (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.
    [Show full text]
  • Source to Surface Model of Monogenetic Volcanism: a Critical Review
    Downloaded from http://sp.lyellcollection.org/ by guest on September 28, 2021 Source to surface model of monogenetic volcanism: a critical review I. E. M. SMITH1 &K.NE´ METH2* 1School of Environment, University of Auckland, Auckland, New Zealand 2Volcanic Risk Solutions, Massey University, Palmerston North 4442, New Zealand *Correspondence: [email protected] Abstract: Small-scale volcanic systems are the most widespread type of volcanism on Earth and occur in all of the main tectonic settings. Most commonly, these systems erupt basaltic magmas within a wide compositional range from strongly silica undersaturated to saturated and oversatu- rated; less commonly, the spectrum includes more siliceous compositions. Small-scale volcanic systems are commonly monogenetic in the sense that they are represented at the Earth’s surface by fields of small volcanoes, each the product of a temporally restricted eruption of a composition- ally distinct batch of magma, and this is in contrast to polygenetic systems characterized by rela- tively large edifices built by multiple eruptions over longer periods of time involving magmas with diverse origins. Eruption styles of small-scale volcanoes range from pyroclastic to effusive, and are strongly controlled by the relative influence of the characteristics of the magmatic system and the surface environment. Gold Open Access: This article is published under the terms of the CC-BY 3.0 license. Small-scale basaltic magmatic systems characteris- hazards associated with eruptions, and this is tically occur at the Earth’s surface as fields of small particularly true where volcanic fields are in close monogenetic volcanoes. These volcanoes are the proximity to population centres.
    [Show full text]
  • 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
    [Show full text]
  • Bailey-1976.Pdf
    VOL. 81, NO. 5 JOURNAL OF GEOPHYSICAL RESEARCH FEBRUARY 10, 1976 Volcanism, Structure,and Geochronologyof Long Valley Caldera, Mono County, California RoY A. BAILEY U.S. GeologicalSurvey, Reston, Virginia 22092 G. BRENT DALRYMPLE AND MARVIN A. LANPHERE U.S. GeologicalSurvey, Menlo Park, California 94025 Long Valley caldera, a 17- by 32-km elliptical depressionon the east front of the Sierra Nevada, formed 0.7 m.y. ago during eruption of the Bishoptuff. Subsequentintracaldera volcanism included eruption of (1) aphyric rhyolite 0.68-0.64 m.y. ago during resurgentdoming of the caldera floor, (2) porphyritic hornblende-biotiterhyolite from centersperipheral to the resurgentdome at 0.5, 0.3, and 0.1 m.y. ago, and (3) porphyritic hornblende-biotiterhyodacite from outer ring fractures0.2 m.y. ago to 50,000 yr ago, a sequencethat apparently records progressivecrystallization of a subjacentchemically zoned magma chamber. Holocene rhyolitic and phreatic eruptions suggestthat residual magma was present in the chamber as recentlyas 450 yr ago. Intracaldera hydrothermalactivity beganat least0.3 m.y. ago and was widespreadin the caldera moat; it has sincedeclined due to self-sealingof near-surfacecaldera sediments by zeolitization, argillization, and silicificationand has becomelocalized on recentlyreactivated north- west-trendingSierra Nevada frontal faults that tap hot water at depth. INTRODUCTION concentrates were treated with a dilute HF solution to remove small bits of attached glassand fragments of other mineral In the westernUnited States,only three calderasare known grains. Obsidian used for dating was totally unhydrated and to be large enoughand young enoughto possiblystill contain not devitrified. Small blocks sawed from many of the hand residual magma in their chambers:the Vailes caldera (•1.1 specimenswere used for dating.
    [Show full text]
  • Stratigraphic Correlation Chart for Western Colorado and Northwestern New Mexico
    New Mexico Geological Society Guidebook, 32nd Field Conference, Western Slope Colorado, 1981 75 STRATIGRAPHIC CORRELATION CHART FOR WESTERN COLORADO AND NORTHWESTERN NEW MEXICO M. E. MacLACHLAN U.S. Geological Survey Denver, Colorado 80225 INTRODUCTION De Chelly Sandstone (or De Chelly Sandstone Member of the The stratigraphic nomenclature applied in various parts of west- Cutler Formation) of the west side of the basin is thought to ern Colorado, northwestern New Mexico, and a small part of east- correlate with the Glorieta Sandstone of the south side of the central Utah is summarized in the accompanying chart (fig. 1). The basin. locations of the areas, indicated by letters, are shown on the index map (fig. 2). Sources of information used in compiling the chart are Cols. B.-C. shown by numbers in brackets beneath the headings for the col- Age determinations on the Hinsdale Formation in parts of the umns. The numbers are keyed to references in an accompanying volcanic field range from 4.7 to 23.4 m.y. on basalts and 4.8 to list. Ages where known are shown by numbers in parentheses in 22.4 m.y. on rhyolites (Lipman, 1975, p. 6, p. 90-100). millions of years after the rock name or in parentheses on the line The early intermediate-composition volcanics and related rocks separating two chronostratigraphic units. include several named units of limited areal extent, but of simi- No Quaternary rocks nor small igneous bodies, such as dikes, lar age and petrology—the West Elk Breccia at Powderhorn; the have been included on this chart.
    [Show full text]
  • Part 629 – Glossary of Landform and Geologic Terms
    Title 430 – National Soil Survey Handbook Part 629 – Glossary of Landform and Geologic Terms Subpart A – General Information 629.0 Definition and Purpose This glossary provides the NCSS soil survey program, soil scientists, and natural resource specialists with landform, geologic, and related terms and their definitions to— (1) Improve soil landscape description with a standard, single source landform and geologic glossary. (2) Enhance geomorphic content and clarity of soil map unit descriptions by use of accurate, defined terms. (3) Establish consistent geomorphic term usage in soil science and the National Cooperative Soil Survey (NCSS). (4) Provide standard geomorphic definitions for databases and soil survey technical publications. (5) Train soil scientists and related professionals in soils as landscape and geomorphic entities. 629.1 Responsibilities This glossary serves as the official NCSS reference for landform, geologic, and related terms. The staff of the National Soil Survey Center, located in Lincoln, NE, is responsible for maintaining and updating this glossary. Soil Science Division staff and NCSS participants are encouraged to propose additions and changes to the glossary for use in pedon descriptions, soil map unit descriptions, and soil survey publications. The Glossary of Geology (GG, 2005) serves as a major source for many glossary terms. The American Geologic Institute (AGI) granted the USDA Natural Resources Conservation Service (formerly the Soil Conservation Service) permission (in letters dated September 11, 1985, and September 22, 1993) to use existing definitions. Sources of, and modifications to, original definitions are explained immediately below. 629.2 Definitions A. Reference Codes Sources from which definitions were taken, whole or in part, are identified by a code (e.g., GG) following each definition.
    [Show full text]
  • 36 CFR Ch. II (7–1–13 Edition) § 294.49
    § 294.49 36 CFR Ch. II (7–1–13 Edition) subpart shall prohibit a responsible of- Line Includes ficial from further restricting activi- Colorado roadless area name upper tier No. acres ties allowed within Colorado Roadless Areas. This subpart does not compel 22 North St. Vrain ............................................ X the amendment or revision of any land 23 Rawah Adjacent Areas ............................... X 24 Square Top Mountain ................................. X management plan. 25 Troublesome ............................................... X (d) The prohibitions and restrictions 26 Vasquez Adjacent Area .............................. X established in this subpart are not sub- 27 White Pine Mountain. ject to reconsideration, revision, or re- 28 Williams Fork.............................................. X scission in subsequent project decisions Grand Mesa, Uncompahgre, Gunnison National Forest or land management plan amendments 29 Agate Creek. or revisions undertaken pursuant to 36 30 American Flag Mountain. CFR part 219. 31 Baldy. (e) Nothing in this subpart waives 32 Battlements. any applicable requirements regarding 33 Beaver ........................................................ X 34 Beckwiths. site specific environmental analysis, 35 Calamity Basin. public involvement, consultation with 36 Cannibal Plateau. Tribes and other agencies, or compli- 37 Canyon Creek-Antero. 38 Canyon Creek. ance with applicable laws. 39 Carson ........................................................ X (f) If any provision in this subpart
    [Show full text]
  • Profiles of Colorado Roadless Areas
    PROFILES OF COLORADO ROADLESS AREAS Prepared by the USDA Forest Service, Rocky Mountain Region July 23, 2008 INTENTIONALLY LEFT BLANK 2 3 TABLE OF CONTENTS ARAPAHO-ROOSEVELT NATIONAL FOREST ......................................................................................................10 Bard Creek (23,000 acres) .......................................................................................................................................10 Byers Peak (10,200 acres)........................................................................................................................................12 Cache la Poudre Adjacent Area (3,200 acres)..........................................................................................................13 Cherokee Park (7,600 acres) ....................................................................................................................................14 Comanche Peak Adjacent Areas A - H (45,200 acres).............................................................................................15 Copper Mountain (13,500 acres) .............................................................................................................................19 Crosier Mountain (7,200 acres) ...............................................................................................................................20 Gold Run (6,600 acres) ............................................................................................................................................21
    [Show full text]
  • Range Fuels at 'End of Road'
    1A 1A HEALTH CARE BOULDER COUNTY & WELLNESS New techniques reduce pain of back problems BUSINESS 11A Serving Boulder and Broomfield Counties REPORT$1 Volume 31 Issue 3 | Feb. 3-9, 2012 Range Fuels at ‘end of road’ BY PAULA MOORE York-based Bloomberg New Energy [email protected] Failed biofuel production plant Finance. “The problem with them was absolutely technological. Their BROOMFIELD — Range Fuels situation tells you that money doesn’t Inc., a Broomfield-based biofuels takes toll on firm in Broomfield guarantee something’s going to work.” company, appears to be out of busi- by an automated system. Its website, “Range Fuels has met the end of But Christine Shapard, executive ness with the recent foreclosure sale www.rangefuels.com, is inactive. the road,” said Kalib Kersh, an analyst director of the Colorado Cleantech of its troubled cellulosic ethanol plant Recent messages left for Range Fuels at Lux Research Inc. in Boston who Industry Association, believes the near Soperton, Georgia. CEO David Aldous in Colorado and followed the Colorado company. state’s biofuels industry overall still The company’s headquarters office company founder/investor Vinod Kho- “With Range Fuels, the issue wasn’t has plenty of potential. She singled near the Interlocken business park is sla of Khosla Ventures LLC in Menlo funding,” said Alejandro Zamorano out companies such as ZeaChem Inc. vacant, and its phone number is answered Park, California, were not returned. Cadavid, a biofuels analyst at New ➤ See End, 15A FDIC has BOULDER AND BEYOND Mile High Boulder Economic Council’s 2012 forecast event paints brighter picture Banks on short leash Bank’s capital condition ‘continues to deteriorate’ BY BETH POTTER [email protected] LONGMONT — Mile High Banks is “significantly undercapitalized,” according to a document released Jan.
    [Show full text]
  • Energy Efficiency, but at What Cost?
    HIGH-TECH PRINTING MARKETPLACE AND GRAPHICS App makes connecting Cool new developments to conference calls easy in large-format printing $1 6A 10A Volume 31 Issue 13 | Date June 8-21, 2012 Energy efficiency, but at what cost? BY MICHAEL DAVIDSON place to start as the city moves toward [email protected] Proposed changes to Boulder’s achieving its climate goals, said Eliza- beth Vasatka, the city’s business sus- BOULDER — As the city of Boul- tainability coordinator. der considers changes to its climate climate action plan spark concern Prior studies have shown energy action plan, businesses and commer- properties. Passing laws that would require use accounts for up to 76 percent of cial property owners are concerned Boulder is reviewing its climate buildings to be more efficient is one of Boulder’s greenhouse gas emissions, about the possibility the city will pass plan and energy strategy, and in May the options the council is considering. and nearly 83 percent of those emis- ordinances requiring them to make the Boulder City Council had a study Making commercial buildings sions come from the industrial and energy-efficiency upgrades to their session on the topic. more energy efficient is an obvious ➤ See Efficiency, 23A ORBITAL TECHNOLOGY Drug race Business is cooking at Custom Microwave Inc. in Longmont lures local companies to fast lane Pharma firms quietly studying biosimilars BY BETH POTTER [email protected] BOULDER — Merck & Co. Inc. and Amgen Inc. — two global phar- maceutical companies with opera- tions in the Boulder Valley – appear to be on the front lines of the new and often-stealthy world of researching biosimilar drugs.
    [Show full text]