DOCSLIB.ORG

Geology at the Crossroads

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Geology at the Crossroads BIG BEND RANCH STATE PARK 4 Geology at the Crossroads By Blaine R. Hall Blaine R. Hall Crossroads: Intersection, Road, and the Oso Loop passes Junction, Gathering Place. Big directly through it. Bend Ranch State Park (BBRSP) has been all of these for at least Basin and Range Trend. the last 11,000 years as Native 4 The fourth geological event Americans, ranchers, miners, s n i a t is marked by development of the freighters, travelers, and now park n Basin Rocky u and Mountains o Basin and Range Province. The visitors have lived and traveled M Range n ia here. The scenery is magnificent h map illustrates how the Basin ac Ouachita Mountains al pp and Range is characterized by and the landscape varies from river A lowlands, through deep canyons, Trans-Pecos north-trending mountains and Volcanic Field Buried across high plateaus, and up steep intervening sediment-filled valleys Marathon Llano Basin Uplift mountains. Ultimately all of this Buried or basins, which began forming is controlled by the character and about 25 Ma. These uplifted variety of the underlying geology ranges and down-dropped basins and the processes that created it are separated by parallel faults. over millions of years. This deformation is due to the E D 1 N 3 A Adapted by Blaine R. Hall But why a crossroads of geology? R G west-to-east stretching of the O A look at the geological map above I Big Bend R earth’s crust that may have 2 Trends of four major geological can answer that question just by Ranch been caused by relaxation of the State Park Big Bend events converge at the park. following the variously colored areas 4 National Colored numbers indicate where compressive force that had built to their convergence in the Big Bend Park each can be viewed. the Rocky Mountains. In the region. The trends illustrated here park, the Basin and Range trend represent the four major events that evident in the white band of rocks is evident along the Rio Grande, have shaped North America over the that bends and contorts along the where the river flows through a past 500+ million years, and all of hillside and across the saddle. 3 them are represented in the park. So, series of elongated basins bounded get in your car, mount up your horse, by long, continuous faults. Photo hop on your bike or strike up a hike 4 shows one of the best-developed and visit the Crossroads of Geology! 2 examples along the north edge of Colorado Mesa, where the bounding fault extends from right Blaine R. Hall to left beyond the photo margin. 1 The shot was taken just west of 47 Ma. and 18 Ma. throughout Closed Canyon. Here the road western North America. The Blaine R. Hall parallels the fault for about 2.5 large Trans-Pecos Volcanic miles east–one of the longest Field was created at this time straight stretches of F.M. 170 in Rocky Mountain Trend. by the eruption of molten rock, 2 the park. About 200 million years called magma, which originated later, the park area was again As you travel through BBRSP, Blaine R. Hall from a slab of oceanic crust covered by an ocean basin, driven from the west deep watch for evidence of all four but this time the rocks were Appalachian/Ouachita/ underground and then melted. geological events–for folds and deposited in a shallow, near-shore 1 Marathon/Solitario Trend. This volcanism had the most faults, lavas and tuffs. Take with environment and consisted Around 520 Ma. (million years direct and profound effect of the you a fuller appreciation for the ago) sandstone, conglomerate, mostly of thick-bedded limestone, four events at BBRSP and is the geological enormity of time and limestone, shale, and chert formed shale, and sandstone. The second most completely represented. scale and the resulting variety of in an ocean basin offshore from major geological event, building The Bofecillos Mountains make landscape and scenic beauty here ancient North America. By 300 Ma. the Rocky Mountains, was up the high, central part of the at the Crossroads. this old ocean was closed up and completed about 50 Ma. here park and were formed at 27 Ma. Additional Information. For a the rocks were strongly deformed in West Texas. This time the by the eruption of very extensive general geological map and trail and uplifted as what is now Africa folding, faulting, and uplift was lava flows and abundant volcanic side geology of the Park pick up collided with eastern North driven by compression originating ash that forms rock called tuff. a copy of Down to Earth at Big America to form the Appalachian at the western margin of North The interior of the Bofecillos Bend Ranch State Park, Texas, Mountains. Concurrently, South America. Photo 2 shows how this Mountains is characterized by and for a more complete and America crashed into the southern event caused once-horizontal high rugged peaks marking old detailed report try Geology of Big edge of North America to form reddish and grey rocks to bend the Ouachita Mountains. This eruption sites and level plateaus Bend Ranch State Park, Texas. and fold from left to right. This same event closed the old ocean where lava flows accumulated, Both are available at any of our one-sided fold marks what is further to the south, extending the while the edges of the mountains visitor centers. known as the Fresno-Terlingua mountain trend into West Texas. are incised by deep canyon The strongly deformed rocks that Monocline, located along the drainages. Photo 3 provides a view southeastern edge of the park in © 2013 Texas Parks and Wildlife Department PWD LF P4501-152P (11/13) are present today in the Marathon of the central Bofecillos vent area, In accordance with Texas State Depository Law, this publication is available at the Texas State Publications Clearinghouse and/or Texas Depository Libraries. Basin can also be seen at BBRSP. the Contrabando area. a source for most of the lavas and TPWD receives federal assistance from the U.S. Fish and Wildlife Service Photo 1 documents this mountain- Trans-Pecos Volcanic tuffs comprising the mountains. and other federal agencies. TPWD is therefore subject to Title VI of the Civil Rights Act of 1964, Section 504 of the Rehabilitation Act of 1973, Title II of the building event, where highly folded 3 Field. Undoubtedly the On the left is Oso Mountain, the Americans with Disabilities Act of 1990, the Age Discrimination Act of 1975, and faulted rocks are exposed in the Title IX of the Education Amendments of 1972, in addition to state anti-dis- most dramatic geological event highest peak in the Park at 5135 crimination laws. TPWD will comply with state and federal laws prohibiting interior walls of the Solitario. The affecting the area was strong feet. The vent area is readily discrimination based on race, color, national origin, age, sex or disability. If strong deformation is particularly you believe that you have been discriminated against in any TPWD program, volcanism that occurred between accessible from the Main Park activity or event, you may contact the U.S. Fish and Wildlife Service, Division of Federal Assistance, 4401 N. Fairfax Drive, Mail Stop: MBSP-4020, Arlington, VA 22203, Attention: Civil Rights Coordinator for Public Access..
Load more

Recommended publications
  • Oaks of the Chihuahuan Desert Region
    International Oaks by Michael Martin Melendrez Los Lunas, New Mexico resented below are 23 species of white oak, six of black • oak, and two intermediate or golden oaks, found in the southwestern United States (primarily New Mexico, Ari­ zona, and western Texas). These nutnbers tnay be disputed by some oaks students. Differences of opinion exist as to the true boundaries of the Chihuahuan Desert the potential hybrid sta­ tus of sotne of the oaks, and their delineation. Also new oaks not previously known to occur in the area are continually dis­ covered. Counting the additional oaks found in the adjacent Mexican State of Chihuahua, there are n1ore than 60 species. The Chihuahuan Desert Region is truly The Land o.fOaks. The production nursery industry of our area has started, on a small scale, the introduction of oaks with a limited species selec­ tion. Unfortunately the southern live oak (Quercus virginiana) usually is the first one to be grown and sold, and it is commonly promoted as the best oak for the desert cit­ ies of the Southwest. The species of oak na­ < Guy & Edith Sternberg tive to this arid part of Author ,\1/ichae/ i\1/elendrez standing below Q. ari zonica the country are 1nuch in Catwalk Can• l'0 /1, Gila National Forest. New Mexico. contd. on pg. 22 International Gales • • • contd. from pg. 21 better adapted here, and thus tnake bet­ ter choices for shade trees than the southern live oak. • At our nursery production progran1 in Los Lunas, New Mexico, at 4,900 feet el­ evation and USDA Zone 6b, the native oaks outperform the southern live oak in speed of growth, heat tolerance in a con­ tainer, and over-wintering success.
    [Show full text]
  • Nonexplosive and Explosive Magma/Wet-Sediment Interaction
    Journal of Volcanology and Geothermal Research 181 (2009) 155–172 Contents lists available at ScienceDirect Journal of Volcanology and Geothermal Research journal homepage: www.elsevier.com/locate/jvolgeores Nonexplosive and explosive magma/wet-sediment interaction during emplacement of Eocene intrusions into Cretaceous to Eocene strata, Trans-Pecos igneous province, West Texas Kenneth S. Befus a,⁎, Richard E. Hanson a, Daniel P. Miggins b, John A. Breyer a, Arthur B. Busbey a a Department of Geology, Texas Christian University, Box 298830, Fort Worth, TX 76129, USA b U.S. Geological Survey, Denver Federal Center, Box 25046, Denver, CO 80225, USA article info abstract Article history: Eocene intrusion of alkaline basaltic to trachyandesitic magmas into unlithified, Upper Cretaceous Received 16 June 2008 (Maastrichtian) to Eocene fluvial strata in part of the Trans-Pecos igneous province in West Texas produced Accepted 22 December 2008 an array of features recording both nonexplosive and explosive magma/wet-sediment interaction. Intrusive Available online 13 January 2009 complexes with 40Ar/39Ar dates of ~47–46 Ma consist of coherent basalt, peperite, and disrupted sediment. Two of the complexes cutting Cretaceous strata contain masses of conglomerate derived from Eocene fluvial Keywords: deposits that, at the onset of intrusive activity, would have been N400–500 m above the present level of phreatomagmatism peperite exposure. These intrusive complexes are inferred to be remnants of diatremes that fed maar volcanoes during diatreme an early stage of magmatism in this part of the Trans-Pecos province. Disrupted Cretaceous strata along Trans-Pecos Texas diatreme margins record collapse of conduit walls during and after subsurface phreatomagmatic explosions.
    [Show full text]
  • Geochronology of the Trans-Pecos Texas Volcanic Field John Andrew Wilson, 1980, Pp
    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/31 Geochronology of the Trans-Pecos Texas volcanic field John Andrew Wilson, 1980, pp. 205-211 in: Trans Pecos Region (West Texas), Dickerson, P. W.; Hoffer, J. M.; Callender, J. F.; [eds.], New Mexico Geological Society 31st Annual Fall Field Conference Guidebook, 308 p. This is one of many related papers that were included in the 1980 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks. Copyright Information Publications of the New Mexico Geological Society, printed and electronic, are protected by the copyright laws of the United States.
    [Show full text]
  • Structure and Dynamics of Surface Uplift Induced by Incremental Sill Emplacement
    Structure and dynamics of surface uplift induced by incremental sill emplacement Craig Magee1, Ian D. Bastow1, Benjamin van Wyk de Vries2, Christopher A.-L. Jackson1, Rachel Hetherington3, Miruts Hagos4, and Murray Hoggett5 1Department of Earth Science and Engineering, Imperial College, London SW7 2BP, UK 2Université Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, F-63000 Clermont-Ferrand, France 3Department of Geological and Mining Engineering and Sciences, Michigan Technological University, Houghton, Michigan 49931, USA 4Department of Earth Sciences, Mekelle University, P.O. Box 231, Mekelle, Tigray, Ethiopia 5School of Geography, Earth and Environmental Science, University of Birmingham, Birmingham B15 2TT, UK ABSTRACT are simple and, critically, non-unique (Galland, Shallow-level sill emplacement can uplift Earth’s surface via forced folding, providing 2012). To address these problems, analyses of insight into the location and size of potential volcanic eruptions. Linking the structure and actively deforming forced folds for which the dynamics of ground deformation to sill intrusion is thus critical in volcanic hazard assess- geological history can be reconstructed are ment. This is challenging, however, because (1) active intrusions cannot be directly observed, required. The Erta’Ale volcanic segment in meaning that we rely on transient host-rock deformation patterns to model their structure; the Danakil depression, a rift basin in northern and (2) where ancient sill-fold structure can be observed, magmatism and deformation has Ethiopia (Fig. 1A), is a superb natural labora- long since ceased. To address this problem, we combine structural and dynamic analyses of tory for studying the surface expression of active the Alu dome, Ethiopia, a 3.5-km-long, 346-m-high, elliptical dome of outward-dipping, tilted magmatism.
    [Show full text]
  • Hinckley Oak (Quercus Hinckleyi)
    Hinckley Oak (Quercus hinckleyi) 5-Year Review: Summary and Evaluation Photo of Hinckley Oak by Mark W. Lockwood, Texas Parks and Wildlife, taken at the Solitario, Big Bend Ranch State Park, Presidio County, Texas U.S. Fish and Wildlife Service Trans-Pecos Sub-Office Alpine, Texas 5-YEAR REVIEW Species reviewed: Hinckley oak (Quercus hinckleyi) 1.0 GENERAL INFORMATION 1.1 Reviewers Lead Regional Office: U.S. Fish and Wildlife Service - Southwest (Region 2) Susan Jacobsen, Chief, Threatened and Endangered Species 505-248-6641 Wendy Brown, Recovery Coordinator, 505-248-6664; Brady McGee, Regional Recovery Biologist, 505-248-6657; Julie McIntyre, Recovery Biologist, 505-248-6657. Lead Field Office: Trans-Pecos Ecological Services Sub-Office, Alpine, Texas Aimee Roberson, Biologist, 432-837-0747. 1.2 Methodology used to complete the review: The public notice for this review was published in the Federal Register on March 20, 2008 (73 FR 14995). This review considers both new and previously existing information from Federal and State agencies, non-governmental organizations, academia, and the general public. Information used in the preparation of the review includes the recovery plan, the Texas Parks and Wildlife Department (TPWD) Natural Diversity Database; a section 6-funded project on propagation, genetic constitution, and reintroduction of the species; unpublished documents; and communications from botanists familiar with the species. The 5-year review document was prepared by staff in the Trans-Pecos Sub-Office of the Austin Ecological Services Field Office without peer review. 1.3 Background: Hinckley oak is an endemic evergreen shrub found on arid limestone slopes in the Chihuahuan desert of the Trans-Pecos region in Presidio County, Texas.
    [Show full text]
  • Trans-Pecos Magmatism Part 9
    Part 9 ! Fig. 108. Needle Peak diatreme and dike viewed from the west. ! Fig. 109. Crustal xenoliths in Needle Peak diatreme. Needle Peak diatreme !368 Eastern termination of W-E dike, choked with crustal xenoliths. Long & Lat Quadrangle 104 47, 30 42.5 Ninetysix Ranch Related to Rim Rock dikes? !Reference: Dasch et al., 1969 !Miocene dikes and lavas associated with Basin-and-Range faulting Sample SM84051 Alkali basalt plug. According to C.D. Henry (personal communication, 2003), this is part of the ~24 Ma Basin & Range-related intrusions, not related to Sawmill Mountain. - SiO2 TiO2 AL2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total 45.10 2.14 14.50 2.92 7.00 9.63 0.16 10.10 9.85 3.63 0.97 0.16 1.50 0.30 0.10 98.88 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb 30 810 20 180 60 Lu Hf Ta Pb Th U MALI @ SiO2 (Na2O+K2O) A.I. Mg# Nb/Zr Y/Nb -5.11 46.50 4.74 0.49 51.2 0.33 0.33 !Ross and Lambert, 1986 Mafic dike north of Terlingua This contains spinel lherzolite and crustal xenoliths, and olivine, clinopyroxene, plagioclase, magnetite and ilmenite. Long & Lat Quadrangle Age, Ma: 24.1 ±0.6 (K-Ar, plagioclase) 103°35.7’, 29°22.2’ Terlingua Sample 8204 Hawaiite. - SiO2 TiO2 Al2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total 46.37 2.20 15.92 1.07 8.90 9.86 0.16 9.35 9.92 4.19 1.35 0.58 100 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er 228 25 775 28 209 65 0.43 2613 62.4 119 49.5 8.71 2.72 1.47 Tm Yb Lu Hf Ta Pb Th U 2.19 0.34 5.62 2.09 5.82 MALI @ SiO2 (Na2O+K2O) A.I.
    [Show full text]
  • Agua Fria Ranch 23,482 +/- Acres, Brewster County
    Agua Fria Ranch 23,482 +/- acres, Brewster County Agua Fria Ranch +/- 23,482 Acres Brewster County, Texas Next to Big Bend Ranch State Park James King, Agent Office 432.426.2024 [email protected] Location Agua Fria Ranch is located 60 minutes south of Alpine, Texas, west of Highway 118 at the end of well-maintained gravel Agua Fria Road. As the Raven flies it's only 12 miles north of Study Butte and Terlingua at the gateway of Big Bend National Park and only 15 miles from Lajitas and its world class golf course and amazing resort amenities, including the drop off into the canyons of the Rio Grande River. This ranch is located adjacent to the 311,000 acre Big Bend Ranch, a nationally recognized wilderness park full of outdoor adventure. The "Lefthand Shutup," a canyon draining the Solitario in Big Bend Ranch, is adjacent to Agua Fria Ranch. Acreage +/- 23,482 acres in Brewster County. Description There are few places in Texas where the legends of the old west and the landscapes that crafted them still combine to create a backdrop so stunning, so authentic, and so historic that yesterday becomes today and the Wild West still calls. Names like Whistler Mesa, Agua Fria Spring, Panther Draw, Horse Tank Draw, Black Ridge, Alamo Cesario Creek, Blackrock Draw, and Soda Spring Draw are names that still describe this historic ranch. It’s also all about the water and the huge natural spring at the base of Agua Fria Mountain. Once the life blood of ancient cultures, today the crystal clear cool waters are distributed into a modern water system providing year- round water throughout the ranch.
    [Show full text]
  • Small-Scale Structures in the Guadalupe Mountains Region: Implication for Laramide Stress Trends in the Permian Basin Erdlac, Richard J., Jr., 1993, Pp
    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/44 Small-scale structures in the Guadalupe Mountains region: Implication for Laramide stress trends in the Permian Basin Erdlac, Richard J., Jr., 1993, pp. 167-174 in: Carlsbad Region (New Mexico and West Texas), Love, D. W.; Hawley, J. W.; Kues, B. S.; Austin, G. S.; Lucas, S. G.; [eds.], New Mexico Geological Society 44th Annual Fall Field Conference Guidebook, 357 p. This is one of many related papers that were included in the 1993 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks.
    [Show full text]
  • Summary of Big Bend National Park GRI Meeting January 15-17, 2002
    Summary of Big Bend National Park GRI meeting January 15-17, 2002 SUMMARY A Geologic Resources Inventory (GRI) workshop was held for Big Bend National Park (BIBE) on January 15-17th, 2002. The purpose was to view and discuss the park’s geologic resources, to address the status of geologic mapping for compiling both paper and digital maps, and to assess resource management issues and needs. Cooperators from the NPS Geologic Resources Division (GRD), Guadalupe Mountains National Park, Redwoods National Park, BIBE, Texas Bureau of Economic Geology, National Resource and Conservation Service, various academic institutions (Sul Ross State University, Texas Tech, and University of Texas PB), and the United States Geologic Survey (USGS) were present for the workshop. The workshop involved field trips to various points of interest in BIBE, led by both various USGS, academic and BIBE staff, as well as another full-day scoping session to present overviews of the NPS Inventory and Monitoring (I&M) program, the GRD, and the on-going GRI. Round table discussions involving geologic issues for BIBE included the status of geologic mapping efforts, interpretation, sources of available data, and action items generated from this meeting. Additionally, a "GeoIndicators" scoping session was tied on to this GRI scoping on the last day. This is part of the NPS GPRA goal Ib4: Identifying Human Influences to Geologic Processes. This portion of the meeting is summarized in a different report available from Vicki Ozaki. For a list of meeting attendees, see Appendix A (List of Cooperators for Big Bend NP GRI Workshop, January 15-17, 2002).
    [Show full text]
  • Download the Scanned
    TIIE AMERICAN MINERALOGISI" VOL. 46, MARCH-APRIL, 1961 MEMORIAL OF JOHN TIPTON LONSDALE E. Wtu. HnrNnrcn, M'ineralogy Deportmenl,,University oJ Mi,chigan. John T. Lonsdale died suddenly and unexpectedly of a heart attack on October 5, 1960at 1:30 e.u. at his home in Austin, Texas. To those who never knew him this can be read as a simple statement of fact. For those of us who knew him and thus loved him no amount of repeti- tion will ever convince us that it is completely true. Who can portray a man by parading the sequenceof his life events? John Tipton Lonsdale, born November 8, 1895 at Dale, Iowa was the oldest son of John Dye Lonsdaleand Eva Mary Lonsdale,nee Connor. After an elementary school education at Dale and high school training at Guthrie Center, he was awarded his B.A. (1917) and M.S. (1921) at the University of Iowa. His studies were interrupted from l9l7 to 1919 when he served as First Lieutenant in the Army of the United Statesduring which time he was cited for bravery by both the United States and Italian governments. Upon his return from war he married Edna Gertrude Von Arnam on August 13, I92I. Mrs. Lonsdalerecalls a long personaldebate in deciding whether to resume with geology or to continue as a professionalmilitary manl he had receiveda commissionas a first lieutenant in the post-war army. Geology won and he began his professional career as Assistant Professorof Geology at the University of Virginia and Assistant Geolo- gist with the Geological Survey of Virginia (192I-1924).
    [Show full text]
  • Solitario Uplift, Presidio-Brewster- Counties, Texas 1
    BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Vol. 32, pp. 417-428 December 1 , 1921 SOLITARIO UPLIFT, PRESIDIO-BREWSTER- COUNTIES, TEXAS 1 BY SIDNEY POWERS (Read before the Society December 29, 1920) CONTENTS P ag e Introduction........ 417 Summary............ 4 1 9 Regional geology 4 2 1 Detailed geology. 42 2 Stratigraphy. 42 2 Structure___ 4 2 5 Origin.................... 4 2 6 I ntroduction The Solitario is a circular dome 5 miles in inside and 7 miles in out­ side diameter, situated 60 miles south of Marfa, west Texas, in both Presidio and Brewster counties (figure 1). It is in the trans-Pecos sec­ tion, 9 miles in a straight line from the Rio Grande, on the western side of the “Big Bend” in the river and 25 miles east of Presidio. Occasional ranches are scattered through this barren mesquite desert, but few are near the highways. Military roads have been constructed from Marfa to Lajitas past the Solitario and to other outposts. There is a wagon road from the Lajitas road past McMahon’s ranch into the north end of the uplift. Although the Solitario is shown on the topographic sheet of the Ter- lingua quadrangle, United States Geological Survey (figure 1), and al­ though it has been visited by several geologists, including G. K. Gilbert, J. A. Udden, and R. T. Hill, nothing has ever been written about it.2 1 Manuscript received by the Secretary of the Society May 17, 1921. 2 It is shown on the “Geological map of a portion of west Texas,” by B.
    [Show full text]
  • Big Bed Ranch State Park
    TABLE OF CONTENTS EXECUTIVE SUMMARY AND ELIGIBILITY .......................................................................... 1 INTERNATIONAL DARK SKY NOMINATION AND SUPPORT LETTERS ......................... 1 PARK DESCRIPTION ................................................................................................................. 14 Environmental Setting .............................................................................................................. 15 Cultural History ........................................................................................................................ 16 Property Description ................................................................................................................. 20 DARK SKIES IN THE BIG BEND REGION ............................................................................. 22 Sky Quality at Big Bend Ranch State Park ............................................................................... 26 All-sky Photometry ............................................................................................................... 26 Sky Quality Meter ................................................................................................................. 30 Photography .......................................................................................................................... 33 Big Bend Ranch State Park Dark Sky Commitment ................................................................ 37 Big Bend Ranch State Park Complex Lightscape
    [Show full text]