DOCSLIB.ORG

Geologic Framework of the Catalina Foothills, Outskirts of Tucson (Pima County, Arizona)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Geologic Framework of the Catalina Foothills, Outskirts of Tucson (Pima County, Arizona) GEOLOGIC FRAMEWORK OF THE CATALINA FOOTHILLS, OUTSKIRTS OF TUCSON (PIMA COUNTY, ARIZONA) W.R. DICKINSON Emeritus, Dept. of Geosciences University of Arizona ARIZONA GEOLOGICAL SURVEY CONTRIBUTED MAP CM-99-B MAY 1999 31 p., scale 1 :24,000 TIus report is preliminary and has not been edited or reviewed for confonnity with Arizona Geological Survey standards. ARIZONA GEOLOGICAL SURVEY CONTRIBUTED MAP CM-99-B (31 pp., 1 Plate) Geologic Framework of the Catalina Foothills, Outskirts of Tucson (Pima County, Arizona) [Text and Legend to Accompany 1:24,000 Map] William R. Dickinson, Department of Geosciences, University of Arizona May 1999 Introduction and Purpose Past geologic maps and accounts of the sedimentary, geomorphic, and structural geology of the piedmont of the Santa Catalina Mountains in the outskirts of Tucson by Voelger (1953), Pashley (1966), Davidson (1973), Creasey and Theodore (1975), Banks (1976), Anderson (1987), Pearthree et al. (1988), McKittrick (1988), and Jackson (1989) raised questions about the sedimentary evolution of the foothills belt that were left open or unresolved. Multiple dissected alluvial fans and pediments overlie much older faulted and tilted strata to form Cenozoic sedimentary assemblages of considerable stratigraphic and structural complexity. As a contribution to improved understanding of urban geology in the Tucson metropolitan area, systematic geologic mapping of the piedmont belt was undertaken to establish the overall geologic framework of the Catalina foothills (~ 175 2 km ) at a common scale (1 :24,000). The area studied extends from Oracle Road on the west to the vicinity of Rinconado Road on the east, and from the Rillito River and Tanque Verde Wash northward to the limit of bedrock exposures at the base of the Santa Catalina Mountains. A dense network of suburban roads allows detailed access to nearly all parts of the Catalina foothills, although multiple gated communities and undeveloped tracts closed to public entry prevent ready access to selected parts of the mapped area. Roadcuts provide the most informative outcrops of most sedimentary units, and many of them did not exist during previous studies. Comparable natural outcrops are limited to fortuitous stream cutbanks and especially steep ravine slopes unmantled by soil cover. Aerial photographs were invaluable accessories to the field work, allowing the continuity of sedimentary entities, or discontinuities between them, to be traced through areas of poor exposure. The irregular distribution of bedding attitudes on the accompanying geologic map is for the most part not reflective of variable intensity offield investigation, but of variable occurrence of adequate exposures. Most outcrops allowing strikes and dips of bedding to be measured with confidence were probably visited during the course of the field work. For clarity of graphic display, all mapped contacts between different sedimentary units on the accompanying geologic map are shown as solid lines, even though normal mapping convention would require long segments of most contacts to be dashed to indicate only approximate location. Exclusive use of solid contact lines should not be interpreted as reflecting fully accurate placement of all contacts. I No attempt was made during the field work to delineate the extent of washfloor alluvium along minor tributary drainages, nor of patches of terrace and pediment gravel that locally mask underlying units. Focus was maintained instead on the distribution of the major depositional units that define the sedimentary framework of the foothills belt. Details of geomorphic evolution and soil development were not addressed. In many areas, thin unmapped surficial deposits of various kinds were laid down on successive erosional surfaces cut across sedimentary units during a long history of progressive denudation that gave rise to the present piedmont landscape (Davidson, 1973, p. E15). Capping soils have accordingly been developed over varying time intervals of exposure on surfaces of varying ages. A legend for the accompanying geologic map follows references to the text. The designations used by previous workers for the various map units are discussed in the text, and presented in thumbnail form (Table 1) following the legend. Owing to the scarcity of definitive outcrops within the Catalina foothills belt, the reader should bear in mind that the placement of contacts between different depositional units by previous workers has inevitably varied somewhat, and few previously mapped contacts are identical to my own. Stream Nomenclature The terminology used for major stream courses requires comment: (a) The trunk stream for Catalina foothills drainages is termed the "Rillito River", following currently available topographic quadrangle maps, although "Rillito Creek" has been common usage in the past (Barnes, 1960, p. 277; Peirce and Kresan, 1984; Pearthree and Baker, 1987; Kresan, 1988). The Spanish etymology of the name ("rillito" = "little river") is compatible with either designation. Following an old Spanish convention for naming streams, the name "Rillito" is not extended upstream beyond the juncture of Tanque Verde Wash with Pantano Wash. (b) Tanque Verde Wash is designated alternately as "Tanque Verde Creek" or "Tanque Verde Wash" on currently available topographic maps, but the latter term is adopted here, by analogy with Agua Caliente Wash and Pantano Wash, for the ephemeral portion of the stream course below where it exits from the mountain front at the foot of Redington Pass. (c) The streams that emerge from the bedrock gorges of Bear, Sabino, and Ventana Canyons are termed, on currently available topographic maps, Bear and Sabino Creeks but "Ventana Canyon Wash". This inconsistency is resolved here by adopting the parallel term "Ventana Creek" for the portion of that stream course below its exit from the mountain front. (d) The piedmont stream course that parallels Pontatoc Road is termed Pontatoc Wash, by analogy with Pima Wash, which exits from Pima Canyon farther west along the mountain front. 2 Overall Piedmont Morphology The Catalina foothills belt is formed by multiple geomorphic surfaces inclined gently downward from the foot of steeper bedrock slopes along the Santa Catalina mountain front toward the courses of the Rillito River and Tanque Verde Wash, which flow subparallel to the mountain front. Net gradients range from a low of 1.0%-1.5% (0.5°-0.9°) east of Bear and Sabino Creeks, through ~2.75% (~1.5°) in the drainages of Pontatoc and Pima Washes on the west, to a high of 4% (2.25°) near the center of the mapped area around Craycroft Road west of Ventana Creek. The upslope extent of the composite piedmont ramp is controlled by the position of the Catalina detachment fault, which structurally defines the northern edge of the sedimented Tucson basin. In general, Quaternary fan and pediment gravels fine from bouldery and cobbly deposits near the mountain front to cobbly and pebbly deposits, with intercalated sandy layers, near the Rillito River and Tanque Verde Wash. The inclined surfaces include both the depositional surfaces of alluvial fans and the erosional surfaces of pediments, although the two kinds of geomorphic features are not readily distinguishable by eye at a distance, nor from the nature of gravels mantling their surfaces. Both kinds of features have been intricately dissected by younger ravines and arroyos, with highstanding piedmont benchlands stranded as remnant surfaces perched well above modern wash floors. West of the juncture of Pantano and Tanque Verde Washes, lateral erosion by the Rillito River has clipped the toe of the composite piedmont ramp to form steep cutbanks rising 25 -50 m above the flank of alluvial flats along the fluvial valley. This erosional trimming of the toe of the piedmont ramp is responsible for much, though not all, of the dissection of the Catalina foothills by local streams tributary to the Rillito River. As fan and pediment toes are clipped by fluvial erosion, tributary streams must incise fan and pediment surfaces to reach grade with respect to the new position of the laterally migrating trunk stream. East of the juncture of Pantano Wash with Tanque Verde Wash near Craycroft Road, the toe of the sloping piedmont ramp merges almost imperceptibly with alluvial flats along Tanque Verde and Agua Caliente Washes. Beyond the southern flank of the Rillito River alluvial flats, basin-fill deposits of the Tucson basin have been etched into multiple post-mid-Pleistocene terrace levels by successive phases offluvial downcutting (Davidson, 1973; Anderson, 1987). Terrrace sediments, composed of detritus stranded in transit on erosional straths cut into basin fill, are typically 15-25 m in maximum thickness (Davidson, 1973, p. E32). The stream terraces are termed the University, Cemetery, and Jaynes terraces in order of decreasing age (Smith, 1938), but none of the three subregional terraces is present north of the Rillito River (McKittrick, 1988). Instead, the piedmont ramp forming the Catalina foothills terminates abruptly at ramp-toe bluffs cut at the flank of alluvial flats along the Rillito River. Upstream from the juncture of Pantano and Tanque Verde Washes, immediately east of the limit of erosional truncation of the toe of the Catalina foothills piedmont ramp by lateral erosion, the Jaynes terrace level may be represented by a dissected stream 3 terrace along the north side of Tanque Verde Wash. The terrace flanks alluvial flats of Tanque Verde Wash as far east as the lowstanding
Load more

Recommended publications
  • CEMOZOIC DEPOSITS in the SOUTHERN FOOTHILLS of the SANTA CATALINA MOUNTAINS NEAR TUCSON, ARIZONA Ty Klaus Voelger a Thesis Submi
    Cenozoic deposits in the southern foothills of the Santa Catalina Mountains near Tucson, Arizona Item Type text; Thesis-Reproduction (electronic) Authors Voelger, Klaus, 1926- Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 25/09/2021 10:53:10 Link to Item http://hdl.handle.net/10150/551218 CEMOZOIC DEPOSITS IN THE SOUTHERN FOOTHILLS OF THE SANTA CATALINA MOUNTAINS NEAR TUCSON, ARIZONA ty Klaus Voelger A Thesis submitted to the faculty of the Department of Geology in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in the Graduate College, University of Arizona 1953 Approved; , / 9S~J Director of Thesis ^5ate Univ. of Arizona Library The research on which this thesis is based was com­ pleted by Mr. Klaus Voelger of Berlin, Germany, while he was studying at the University of Arizona under the program of the Institute of International Education. The final draft was written after Mr. Voelgerf s return to his home in the Russian-occupied zone of Berlin. Difficulties such as a shortage of typing paper of uniform grade and the impossibility of adequate supervision and advice on matters of terminology, punctuation, and English usage account for certain details in which this thesis may depart from stand­ ards of the Graduate College of the University of Arizona. These details are largely mechanical, and it is felt that they do not detract appreciably from the quality of the research nor the clarity of presentation of the results.
    [Show full text]
  • Cultural Heritage the Mountains and Foothills of North Carolina Have Over Many Centuries Fostered a Rich Mosaic of Cultural Heritage
    Western North Carolina Vitality Index Cultural Heritage www.wncvitalityindex.org The mountains and foothills of North Carolina have over many centuries fostered a rich mosaic of cultural heritage. The birthplace of the Cherokee’s advanced early civilization, the region is home today to the Eastern Band of Cherokee Indians, which continues to preserve many facets of traditional Cherokee culture. Beginning in the eighteenth century, European and African settlers moved into the mountains. The relative isolation of mountain life helped these settlers refine and preserve many traditions, most notably handmade crafts, traditional music, and local agricultural practices. Today, these distinctive cultural legacies are celebrated as living traditions, providing employment to master artists and tradition bearers and drawing tourists from across the globe to experience the region’s craft galleries, music halls, festivals, museums, farms, and local cuisine. photo courtesy of Blue Ridge National this project has been funded by Heritage Area a project of Blue Ridge National Heritage Area Designation A National Heritage Area is a place designated by the United States Congress where natural, cultural, historic, and recreational resources combine to form a cohesive, nationally distinctive landscape arising from patterns of human activity shaped by geography. Currently, there are 49 National Heritage Areas across the United States, where each area shares how their people, resources, and histories come together to provide experiences that “tell America’s story” and to encourage the community to join together around a common theme and promote the cultural, natural, and recreational benefits of the area. In November 2003, Western North Carolina (WNC) was designated the Blue Ridge National Heritage Area in recognition of the region’s agriculture, craft heritage, traditional music, the distinctive living traditions of Cherokee culture, and rich natural heritage, and their significance to the country.
    [Show full text]
  • Ecoregions of New England Forested Land Cover, Nutrient-Poor Frigid and Cryic Soils (Mostly Spodosols), and Numerous High-Gradient Streams and Glacial Lakes
    58. Northeastern Highlands The Northeastern Highlands ecoregion covers most of the northern and mountainous parts of New England as well as the Adirondacks in New York. It is a relatively sparsely populated region compared to adjacent regions, and is characterized by hills and mountains, a mostly Ecoregions of New England forested land cover, nutrient-poor frigid and cryic soils (mostly Spodosols), and numerous high-gradient streams and glacial lakes. Forest vegetation is somewhat transitional between the boreal regions to the north in Canada and the broadleaf deciduous forests to the south. Typical forest types include northern hardwoods (maple-beech-birch), northern hardwoods/spruce, and northeastern spruce-fir forests. Recreation, tourism, and forestry are primary land uses. Farm-to-forest conversion began in the 19th century and continues today. In spite of this trend, Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and 5 level III ecoregions and 40 level IV ecoregions in the New England states and many Commission for Environmental Cooperation Working Group, 1997, Ecological regions of North America – toward a common perspective: Montreal, Commission for Environmental Cooperation, 71 p. alluvial valleys, glacial lake basins, and areas of limestone-derived soils are still farmed for dairy products, forage crops, apples, and potatoes. In addition to the timber industry, recreational homes and associated lodging and services sustain the forested regions economically, but quantity of environmental resources; they are designed to serve as a spatial framework for continue into ecologically similar parts of adjacent states or provinces. they also create development pressure that threatens to change the pastoral character of the region.
    [Show full text]
  • Pantano Wash - Rillito River Watershed Arizona Rapid Watershed Assessment June 2007
    Pantano Wash - Rillito River Watershed Arizona Rapid Watershed Assessment June 2007 Prepared by: USDA Natural Resource Conservation Service – Arizona University of Arizona, Water Resources Research Center In cooperation with: Arizona Association of Conservation Districts Arizona Department of Agriculture Arizona Department of Environmental Quality Arizona Department of Water Resources Arizona Game & Fish Department Arizona State Land Department USDA Forest Service USDI Bureau of Land Management Released by: Sharon Megdal David McKay Director State Conservationist University of Arizona U.S. Department of Agriculture Water Resources Research Center Natural Resources Conservation Service Additional Principal Investigators: Dino DeSimone – Natural Resources Conservation Service, Phoenix, Arizona Keith Larson – Natural Resources Conservation Service, Phoenix, Arizona Kristine Uhlman – Water Resources Research Center, University of Arizona D. Phil Guertin – School of Natural Resources, University of Arizona Deborah Young – Associate Director, Cooperative Extension, University of Arizona The United States Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact
    [Show full text]
  • Pantano Wash
    Released by: Sharon Medgal David McKay Director State Conservationist University of Arizona U.S. Department of Agriculture Water Resources Research Center Natural Resources Conservation Service Principle Investigators: Dino DeSimone - Natural Resources Conservation Service, Phoenix, Arizona Keith Larson - Natural Resources Conservation Service, Phoenix, Arizona Kristine Uhlman - Water Resources Research Center, University of Arizona D. Phil Guertin - School of Natural Resources, University of Arizona Cite as: USDA Natural Resource ConservationConservations Service, Serivce, Arizona Arizona and and University University of of Arizona Arisona Water Water Resources Resources Research Center. 2008. Little Colorado River HeadwatersHeadwaters, Watershed, Arizona, Rapid Arizona, Watershed Rapid WatershedAssessment. Assessment. The United States Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD). To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326W, Whitten Building, 14th and Independence Avenue, SW, Washington, D.C., 20250-9410 or call (202) 720-5964 (voice or TDD).
    [Show full text]
  • Geologic Map of the Redington 7½' Quadrangle, Cochise, Graham, And
    Geologic Map of the Soza Canyon 7½' Quadrangle, Cochise and Pima Counties, Arizona by Jon E. Spencer, Stephen M. Richard, Joseph P. Cook, William R. Dickinson, Steven H. Lingrey, and Jerome H. Guynn Arizona Geological Survey Digital Geologic Map DGM-61 version 2.0 May, 2009 Scale 1:24,000 (1 sheet, with text) Arizona Geological Survey 416 W. Congress St., #100, Tucson, Arizona 85701 This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program, award no. 06HQAG0051. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. Geologic Map of the Soza Canyon 7½' Quadrangle, Cochise and Pima Counties, Arizona by Jon E. Spencer, Stephen M. Richard, Joseph P. Cook, William R. Dickinson, Steven H. Lingrey, and Jerome H. Guynn INTRODUCTION The Soza Canyon 7 ½′ Quadrangle includes part of the San Pedro River, flanking valley fill, and bedrock on the southwest side of the valley that forms part of the Rincon Mountains (Figure 1). Production of this new geologic map continues the Arizona Geological Survey mapping program of the San Pedro River valley. This mapping was done under the joint State-Federal STATEMAP program, as specified in the National Geologic Mapping Act of 1992, and was jointly funded by the Arizona Geological Survey and the U.S. Geological Survey under STATEMAP Program Contract award number 06HQAG0051. Mapping was compiled digitally using ESRI ArcGIS software. Parts of the Soza Canyon 7 ½′ Quadrangle were mapped previously by Thorman and Drewes (1981), Lingrey (1982), Dickinson (1987, 1991, 1998), and Dickinson and Olivares (1987).
    [Show full text]
  • South Carolina Landform Regions (And Facts About Landforms) Earth Where Is South Carolina? North America United States of America SC
    SCSouth Carolina Landform Regions (and facts about Landforms) Earth Where is South Carolina? North America United States of America SC Here we are! South Carolina borders the Atlantic Ocean. SC South Carolina Landform Regions Map Our state is divided into regions, starting at the mountains and going down to the coast. Can you name these? Blue Ridge Mountains Landform Regions SC The Blue Ridge Mountain Region is only 2% of the South Carolina land mass. Facts About the Blue Ridge Mountains . ◼ It is the smallest of the landform regions ◼ It includes the state’s highest point: Sassafras Mountain. ◼ The Blue Ridge Mountains are part of the Appalachian Mountain Range Facts About the Blue Ridge Mountains . ◼ The Blue Ridge Region is mountainous and has many hardwood forests, streams, and waterfalls. ◼ Many rivers flow out of the Blue Ridge. Blue Ridge Mountains, SC Greenville Spartanburg Union Greenwood Rock Hill Abbeville Piedmont Landform Regions SC If you could see the Piedmont Region from space and without the foliage, you would notice it is sort of a huge plateau. Facts About the Piedmont Region . ◼ The Piedmont is the largest region of South Carolina. ◼ The Piedmont is often called The Upstate. Facts About the Piedmont Region . ◼ It is the foothills of the mountains and includes rolling hills and many valleys. ◼ Piedmont means “foot of the mountains” ◼ Waterfalls and swift flowing rivers provided the water power for early mills and the textile industry. Facts About the Piedmont Region . ◼ The monadnocks are located in the Piedmont. ◼ Monadnocks – an isolated or single hill made of very hard rock.
    [Show full text]
  • New Particle Formation Infrequently Observed in Himalayan Foothills – Why?
    Atmos. Chem. Phys., 11, 8447–8458, 2011 www.atmos-chem-phys.net/11/8447/2011/ Atmospheric doi:10.5194/acp-11-8447-2011 Chemistry © Author(s) 2011. CC Attribution 3.0 License. and Physics New particle formation infrequently observed in Himalayan foothills – why? K. Neitola1, E. Asmi1, M. Komppula2, A.-P. Hyvarinen¨ 1, T. Raatikainen1,3, T. S. Panwar4, V. P. Sharma4, and H. Lihavainen1 1Finnish meteorological Institute, Helsinki, Finland 2Finnish meteorological Institute, Kuopio, Finland 3Georgia Institute of Technology, Atlanta, Georgia, USA 4Energy and Resource Institute, New Delhi, India Received: 10 December 2010 – Published in Atmos. Chem. Phys. Discuss.: 29 April 2011 Revised: 29 July 2011 – Accepted: 16 August 2011 – Published: 19 August 2011 Abstract. A fraction of the Himalayan aerosols originate 1 Introduction from secondary sources, which are currently poorly quan- tified. To clarify the climatic importance of regional sec- Secondary particle formation from gaseous precursors is ondary particle formation in the Himalayas, data from 2005 largely recognised as an important worldwide mechanism in- to 2010 of continuous aerosol measurements at a high- creasing the number of atmospheric particles (Kulmala et al., altitude (2180 m) Indian Himalayan site, Mukteshwar, were 2004; Spracklen et al., 2006, 2009). While in the atmo- analyzed. For this period, the days were classified, and the sphere, these particles are affected by several physical and particle formation and growth rates were calculated for clear chemical processes influencing the particle climatic proper- new particle formation (NPF) event days. The NPF events ties, such as their scattering and absorbing characteristics and showed a pronounced seasonal cycle. The frequency of the their ability to act as Cloud Condensation Nuclei (CCN).
    [Show full text]
  • Physiographic Map of Virginia Counties
    Physiographic Map of FREDERICK Winchester CLARKE Virginia Counties LOUDOUN WARREN 2000 ARLINGTON FAUQUIER FAIRFAX C. Roberts & C.M. Bailey, College of William & Mary SHENANDOAHM RAPPAHANNOCK PRINCE F WILLIAM PAGE CULPEPER AP ML Modified from Virginia Division of Mineral Resources/ STAFFORD U.S. Geological Survey Map of Mineral Producing Localities ROCKINGHAM MADISON HIGHLAND Fredericksburg KING http://minerals.usgs.gov/minerals/pubs/state/985199mp.pdf RV GREENE GEORGE ORANGE WESTMORELAND 0 50 100 AUGUSTA ALBEMARLE SPOTSYLVANIA RICHMOND BATH Charlottesville CAROLINE miles GV LOUISA CU CU NORTHUMBERLAND KINGESSEX CL BM 0 50 100 ROCKBRIDGE nBR KING FLUVANNA HANOVER ALLEGHANY & LANCESTER kilometers NELSON WILLIAMQUEEN CL GOOCHLAND ACCOMACK HENRICO CU MIDDLESEX BM AMHERST BUCKINGHAM Richmond POWHATAN NEW GLOUCESTER BOTETOURT KENT MATHEWS CRAIG JAMES APPOMATTOX CHESTER CHARLES FIELD CITY CITY Lynchburg CUMBERLANDAMELIA CL YORK NORTHAMPTON GILES ROANOKE BEDFORD NEWPORT Roanoke PRINCE PRINCE NEWS BUCHANAN GEORGE RV MONTGOMERY CAMPBELL EDWARD NOTTOWAY DICKENSON BLAND SURRY HAMPTON TAZEWELL F DINWIDDIE AP PULASKI CHARLOTTE CU ISLE OF GV FRANKLIN SUSSEX WISE RUSSELL LUNENBURG WIGHT WYTHE FLOYD OP Norfolk BRUNSWICK SMYTH sBR VIRGINIA BEACH PITTSYLVANIA SOUTHAMPTON BM HALIFAX CHESAPEAKECL CARROLL MECKLENBURG PATRICK SCOTT WASHINGTON GRAYSON LEE HENRY GREEN- CL NANSEMOND SVILLE Appalachian Plateau Valley & Ridge Blue Ridge Piedmont Coastal Plain province province province province province AP- Rugged, well-dissected RV- Ridge & Valley nBR- northern Blue Ridge F- Foothills subprovince: CU- Upland subprovince: landscape with dendritic subprovince: long linear subprovince: rugged region region with broad rolling broad upland with low slopes drainage pattern. Elevation- ridges separated by linear with steep slopes narrow hills and moderate slopes. and gentle drainage divides. 1000'-3000' with High Knob valleys with trellis ridges, broad mountains, Elevation 400'-1000' with Steep slopes develop where dissected by stream erosion.
    [Show full text]
  • Chapter 3. Vanishing Riparian Mesquite Bosques: Their Uniqueness and Recovery Potential
    Chapter 3. Vanishing Riparian Mesquite Bosques: Their Uniqueness and Recovery Potential R. Roy Johnson, Tanner S. Carothers, and Steven W. Carothers Introduction The “mesquite bosque” (Spanish for “forest” or “woodland”), one of the most unique and productive southwestern riparian habitat types, was once far more abundant than it is today. Twenty-five years ago, Stromberg (1993), with a focus on Arizona, provided an excellent review on the ecology, decline, existing threats, and potential for recovery of these mesquite forests. By 1993 the iconic mesquite bosque riparian habitat was in serious decline, due primarily to anthropogenic activities. Stromberg (1993) observed that previous attempts at habitat restoration were of limited success and indicated that much of the significant bosque habitat loss was largely the result of human-induced changes in the biotic and abiotic conditions and processes in river floodplains specifically required by species of mesquite (Prosopis spp.). In this chapter, we update elements of Stromberg’s 1993 review and provide a classification between two types of bosques based on distinct vegetation associations along a relatively dry to wet riparian continuum. We also discuss the uniqueness of mesquite bosques as wildlife habitat and chronicle the loss of some of the more distinctive of these forests in Arizona as well as conditions that led to their disappearance. Lastly, we suggest opportunities for a timely approach to mesquite habitat restoration that will likely arise as a result of recent litigation resolution between the Department of Agriculture and the Center for Biological Diversity and the Maricopa Audubon Society. The Mesquite Bosque Mesquite (Prosopis spp.) forests, or bosques, historically represented one of the most widespread of riparian communities in the Southwest.
    [Show full text]
  • A Photographic Field Guide to the Birds of India
    © Copyright, Princeton University Press. No part of this book may be 4 BIRDS OF INDIAdistributed, posted, or reproduced in any form by digital or mechanical means without prior written permission of the publisher. INTRODUCTION Birds of the Indian subcontinent an overview by Carol and Tim Inskipp The Indian subcontinent has a great wealth of birds, making it a paradise for the birdwatcher. The classic Handbook of the Birds of India and Pakistan by Salim Ali and S Dillon Ripley, which covers the whole region and was first published in 1968-1975, lists over 1,200 species. With additional recording and following the more up-to-date nomenclature in the Howard and Moore Complete Checklist of Birds of the World edited by E. C. Dickinson (2003) the current species total for the subcontinent stands at 1,375 species – 13 per cent of the world’s birds. A further relevant reference is Birds of South Asia: the Ripley Guide by Pamela Rasmussen and John Anderton, which has adopted much narrower species Dr. Salim Ali limits and, consequently, the latest edition (2012) recognises 1451 species in the region. Note that less than 800 species are found in all of North America. The Indian subcontinent is species-rich partly because of its wide altitudinal range extending from sea level up to the summit of the Himalayas, the world’s highest mountains. Another reason is the region’s highly varied climate and associated diverse vegetation. The extremes range from the almost rainless Great Indian or Thar Desert, where temperatures reach over 55°C, to the wet evergreen forests of the Assam Hills where 1,300 cm of rain a year have bee recorded at Cherrapunji – one of the wettest places on Earth, and the Arctic conditions of the Himalayan peaks where only alpine flowers and cushion plants flourish at over 4,900 m.
    [Show full text]
  • Geology of the Oracle Ridge Mine and Mining District, Pima County, AZ
    Geology of the Oracle Ridge Mine and Mining District Pima County, Arizona Contributions from the Staff of Oracle Ridge Mining Partners, Jon Spencer, and Excerpts from GSA Memoir 153 Edited by Mark Miller Guidebook for the Arizona Geological Society Spring Field Trip [April 1995] Arizona Geological Society P.O. Box 40952, Tucson, AZ 85717 THIS PAGE INTENTIONALLY BLANK Geology of the Oracle Ridge Mine and Mining District Pima County, Arizona Contributions from the Staff of Oracle Ridge Mining Partners, Jon Spencer, and Excerpts from GSA Memoir 153 Edited by Mark Miller Guidebook for the Arizona Geological Society Spring Field Trip [April 1995) Arizona Geological Society P.O. Box 40952, Tucson, AZ 85717 April 15, 1995 Dear Field Trip Participant: I bid you welcome to the 1995 spring field trip of the Arizona Geological Society. Today, we will be visiting the Oracle Ridge Mine owned and operated by the Oracle Ridge Mining Partners. The trip will encompass both a surface and underground look at a 1OOOTPD copper mine. The orebodies are hosted in Paleozoic carbonates which occur as a roof pendant above a Laramide quartz diorite intrusion and have been later structurally deformed. ORMP list reserves (in the proven and probable catagory) at 9.6 million tons at 2.32% Cu principally as chalcopyrite, chalcocite and bornite, There is a little gold and silver byproduct. I wish to thank the staff and management of ORMP for their permission to visit itt their operation. I would also like to thank Jon Spencer for his resume on the ... geology of the Catalina Mountains.
    [Show full text]