Highwood Mountains Range Analysis Project Area on Those Resources Affected by Implementation

Total Page:16

File Type:pdf, Size:1020Kb

Highwood Mountains Range Analysis Project Area on Those Resources Affected by Implementation United States Department of Agriculture Environmental Forest Service Assessment 2015 Highwood Mountains Range Judith Ranger District, Lewis and Clark National Forest Cascade, Choteau and Judith Basin Counties, Montana For More Information Contact: Lewis and Clark National Forest Judith Ranger District Standford, Montana www.fs.fed.us/r1/lewisclark/projects 406-566-2292. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual’s income is derived from any public assistance program. (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 TTY). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, SW., Washington, DC 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 (TTY). USDA is an equal opportunity provider and employer. Environmental Assessment Table of Contents Introduction ...................................................................................................................................................4 Location of the Proposed Project Area ..........................................................................................................4 Purpose and Need for the Proposal ...............................................................................................................5 Purpose for the Proposal ...........................................................................................................................5 Need for the Proposal ................................................................................................................................6 Who Will Make the Decision and What Will Be Considered .......................................................................8 Public Involvement ........................................................................................................................................9 Proposed Action and Alternatives .................................................................................................................9 Alternative 1- No Action(No Grazing) ................................................................................................... 10 Alternative 2-Current Grazing Management........................................................................................... 10 Alternative 3 – Proposed Adaptive Grazing Management ...................................................................... 11 Environmental Impacts of the Proposed Action and Alternatives............................................................... 14 A: Past, Present, and Reasonably Foreseeable Activities ....................................................................... 14 B: Range .................................................................................................................................................. 14 Alternative 1 – No Grazing ................................................................................................................. 25 Alternative 2 – Current Management .................................................................................................. 25 Alternative 3 – Proposed Action - Adaptive Management .................................................................. 29 C: Watershed .......................................................................................................................................... 35 Alternative 1 – No-Action/No Grazing ............................................................................................... 46 Alternative 2 –Current Management ................................................................................................... 46 Alternative 3 – Proposed Action ......................................................................................................... 47 D: Fisheries ............................................................................................................................................ 49 Effects Common to All Alternatives ................................................................................................... 51 Conclusions by Alternative ................................................................................................................. 53 E: Economics ......................................................................................................................................... 57 Alternative 1 – No Grazing ................................................................................................................. 67 Alternative 2 – No Action (Current Grazing Program) ....................................................................... 69 Alternative 3 – Proposed Action ......................................................................................................... 70 Cumulative Effects .............................................................................................................................. 72 F: Wildlife .............................................................................................................................................. 73 Existing Condition ............................................................................................................................... 73 Threatened, Endangered, Candidate and Proposed Species ................................................................ 81 Sensitive Species ................................................................................................................................. 84 Sensitive Wildlife Species Analyzed ................................................................................................... 85 Management Indicator Species Analyzed ........................................................................................... 96 Migratory Birds ................................................................................................................................. 116 G: Soils .................................................................................................................................................. 126 Alternative 1 – No Action ................................................................................................................. 132 Alternative 2 – Current Management ................................................................................................ 133 Alternative 3 – Adaptive Management .............................................................................................. 134 H: Recreation ....................................................................................................................................... 136 Alternative 1 – No Action ................................................................................................................. 137 Alternative 2 – Current Management ................................................................................................ 138 Alternative 3 – Adaptive Management .............................................................................................. 138 I: Inventoried Roadless Areas .............................................................................................................. 139 Direct, Indirect and Cumulative Effects ............................................................................................ 140 J: Sensitive Plants ................................................................................................................................. 141 Existing Condition ............................................................................................................................. 141 i Name of Project Alternative 1 – No Action ................................................................................................................ 145 Effects Common to All Action Alternatives (2 and 3) ..................................................................... 146 K: Noxious Weeds .............................................................................................................................. 148 Alternative 1 – No Grazing .............................................................................................................. 150 Alternative 2 – Current Management ............................................................................................... 150 L: Heritage .......................................................................................................................................... 153 Alternative 1 - No Action ................................................................................................................. 156 Alternative 2 – Current Grazing Permits Renewed .......................................................................... 156 Alternative 3 – Adaptive Management Strategies ............................................................................ 157 Agencies and Persons Consulted .............................................................................................................
Recommended publications
  • Geological Sukvey
    DEPABTMENT OF THE IHTERIOE BULLETIN OF THE UNITED STATES GEOLOGICAL SUKVEY No. 148 WASHINGTON' G-OVEKNMENT PRINTING OFFICE 1897 UNITED STATES GEOLOGICAL SUEYEY CHARLES D. WALCOTT, 'DIRECTOR ANALYSES OF ROCKS ANALYTICAL METHODS LABORATORY OF THE UNITED STATES GEOLOGICAL SURVEY 1880 to 1896 BY F. W. CLAEKE AND W. F. HILLEBEAND WASHINGTON GOVERNMENT PRINTING OFFICE 1897 CONTENTS. Pago. Introduction, by F. W. Clarke ....'.......................................... 9 Some principles and methods of analysis applied to silicate rocks; by W. F. Hillebrand................................................................ 15 Part I. Introduction ................................................... 15 Scope of the present paper .......................................... 20 Part II. Discussion of methods ..................................i....... 22 Preparation of sample....................:.......................... 22 Specific gravity. ............................: ......--.........--... 23 Weights of sample to be employed for analysis....................... 26 Water, hygroscopic ................................ ................. 26 Water, total or combined....... ^.................................... 30 Silica, alumina, iron, etc............................................ 34 Manganese, nickel, cobalt, copper, zinc.............................. 41 Calcium and strontium...................................... ........ 43 Magnesium......................................................... 43 Barium and titanium............... .... ............................
    [Show full text]
  • The Catalyst
    THE CATALYST Vol. 47, No. 3 The Independent Student Newspaper of Colorado College September 16, 2016 East Campus Housing Designs Revealed plan in place for how this will work. By RILEY HUTCHINGS Living in any of these rooms Come next fall, what looks like an should cost the same amount as empty lot now will house 154 Colo- living in Jackson, Arthur, or the rado College students. Construc- Western Ridge Apartments. tion began on July 25, 2016 and is The construction project is mak- scheduled to be completed on July ing progress every day. The new 1, 2017. buildings will be powered by geo- The complex will consist of two thermal heating, which will be in small houses and six apartments. place by this Friday, Sept. 14. This The two houses will face Uintah energy will fuel the new construc- Street and be similar to the exist- tion and will be available for school ing Jackson and Arthur Houses. use, if CC decides to build more in Four apartments will stretch along the future. Nevada Avenue and will mimic the Two weeks ago, workers finished style of the neighborhood around laying the electrical, sewage, water, the east side of campus. Behind and gas utilities. Next week start- those will be the final two “Brown- ing at 7 a.m. every day, work on the stone” apartments, along with a foundations for the buildings will community building. begin. By early November, 120 park- The community building will face ing spaces will open up for students. Pike’s Peak and include a class- “In order to meet the July 1, 2017 room and laundry facilities for the deadline, we need every bit of complex.
    [Show full text]
  • Description of the Fort Benton Quadrangle
    DESCRIPTION OF THE FORT BENTON QUADRANGLE. INTRODUCTION. steeply inclined sides. In the center of the range of the throat of a volcano, the dikes which radiate heat and cold, varying greatly, of course, with the the limestones and other stratified rocks are hori­ from these centers of activity, and the loose mate­ altitude. The annual rainfall is from 13 to 20 General relations. The Fort Benton quad­ zontal, or nearly so, while on the flanks structure of rials and lava flows of which the cones Structure_. , of. inches, being greatest in the mountains; June and rangle extends in longitude from 110° to 111° of the mountains they are sharply BheuLMoun- were built. The sedimentary strata October are the rainy months. The snowfall is and in latitude from 47° to 48°. It is inclined and dip away from the moun­ through which the volcanoes broke up heavy and the mountain tracts are well watered. 69.25 miles Ions; from north to south. extent°ofan tains to the lower plains country. The horizontal and upon which their materials accumulated are, Agriculture is therefore confined to the foothills . quadrangle. 47.36 miles wide, and contains 3272.7 attitude is well shown in the rocks of Belt Park, over most of the area, nearly horizontal or inclined and stream bottoms, except where irrigation is square miles. It includes part of Choteau, the whereas farther north the mountain masses near gently to the north. These rocks belong entirely possible. northwest corner of Fergus, and the eastern part Monarch are formed of blocks of tilted limestones to the Cretaceous system, and denudation has Culture.
    [Show full text]
  • 2019 Montana Completed Projects
    2019 MONTANA COMPLETED PROJECTS 76,880 $13,933,555 TOTAL ACRES MISSION IMPACT 2019 LAND P R O T E C T I O N & ACCESS IN 2019, WE PROTECTED 6,388 ACRES, PROVIDING ACCESS TO 47,416 ACRES VALUED AT $9,750,000 Acres Acres Reported Project Brief Project Details Protected Access Value Permanent land/access project along Rocky Mountain Front Falls Creek 442 27,001 $2,460,000 conveyed wildlife/riparian habitat to Helena-Lewis and Clark National Forest Expansion of land protection & public access complementing Tenderfoot Creek II 448 9,341 $980,000 8,220 acres of previous work in the vicinity, conveyed to Lewis and Clark National Forest Donation to RMEF that protects critical elk/mule deer/ Bearmouth 3,450 5,200 $2,760,000 whitetail winter range and riparian habitat Permanent land/access project along Rocky Mountain Front Green Mountain 620 2,056 $837,000 conveyed land to Helena-Lewis and Clark Natl Forest & benefits National Trails System Acquired & conveyed two inholdings featuring wildlife & Mill Creek Arrow Peak 470 1,595 riparian habitat to Gallatin Natl Forest west of Absaroka Beartooth Wilderness TENDERFOOT CREEK II FALLS CREEK GREEN MOUNTAIN LAND PROTECTION & ACCESS continued MOUNT HAGGIN Acres Acres Reported Project Brief Project Details Protected Access Value Multi-partner collarboration led to construction of a 2.7-mile Crazy Mountains - 0 1,265 trail opening access to Crazy Mountains, resolving long-time Porcupine - Ibex Trail I access disputes Important corridor for elk & other wildlife RMEF purchased Swan Range 638 638 $2,234,000 from a private landowner & conveyed to Lolo Natl Forest Dome Mountain WMA Addition Assisted partners with the purchase/conveyance of vital elk 160 160 (A.
    [Show full text]
  • Summits on the Air – ARM for USA - Colorado (WØC)
    Summits on the Air – ARM for USA - Colorado (WØC) Summits on the Air USA - Colorado (WØC) Association Reference Manual Document Reference S46.1 Issue number 3.2 Date of issue 15-June-2021 Participation start date 01-May-2010 Authorised Date: 15-June-2021 obo SOTA Management Team Association Manager Matt Schnizer KØMOS Summits-on-the-Air an original concept by G3WGV and developed with G3CWI Notice “Summits on the Air” SOTA and the SOTA logo are trademarks of the Programme. This document is copyright of the Programme. All other trademarks and copyrights referenced herein are acknowledged. Page 1 of 11 Document S46.1 V3.2 Summits on the Air – ARM for USA - Colorado (WØC) Change Control Date Version Details 01-May-10 1.0 First formal issue of this document 01-Aug-11 2.0 Updated Version including all qualified CO Peaks, North Dakota, and South Dakota Peaks 01-Dec-11 2.1 Corrections to document for consistency between sections. 31-Mar-14 2.2 Convert WØ to WØC for Colorado only Association. Remove South Dakota and North Dakota Regions. Minor grammatical changes. Clarification of SOTA Rule 3.7.3 “Final Access”. Matt Schnizer K0MOS becomes the new W0C Association Manager. 04/30/16 2.3 Updated Disclaimer Updated 2.0 Program Derivation: Changed prominence from 500 ft to 150m (492 ft) Updated 3.0 General information: Added valid FCC license Corrected conversion factor (ft to m) and recalculated all summits 1-Apr-2017 3.0 Acquired new Summit List from ListsofJohn.com: 64 new summits (37 for P500 ft to P150 m change and 27 new) and 3 deletes due to prom corrections.
    [Show full text]
  • Inactive Mines on Gallatin National Forest-Administered Land
    Abandoned-Inactive Mines on Gallatin National Forest-AdministeredLand Montana Bureau of Mines and Geology Abandoned-Inactive Mines Program Open-File Report MBMG 418 Phyllis A. Hargrave Michael D. Kerschen CatherineMcDonald JohnJ. Metesh PeterM. Norbeck RobertWintergerst Preparedfor the u.s. Departmentof Agriculture ForestService-Region 1 Abandoned-Inactive Mines on Gallatin National Forest-AdministeredLand Open-File Report 418 MBMG October 2000 Phyllis A. Hargrave Michael D. Kerschen Catherine McDonald John J. Metesh Peter M. Norbeck Robert Wintergerst for the U.S. Department of Agriculture Forest Service-Region I Prepared Contents List of Figures .V List of Tables . VI IntToduction 1 1.IProjectObjectives 1 1.2AbandonedandInactiveMinesDefined 2 1.3 Health and Environmental Problems at Mines. 3 1.3.1 Acid-Mine Drainage 3 1.3.2 Solubilities of SelectedMetals 4 1.3.3 The Use of pH and SC to Identify Problems. 5 1.4Methodology. 6 1.4.1 Data Sources : 6 1.4.2Pre-Field Screening. 6 1.4.3Field Screening. 7 1.4.3.1 Collection of Geologic Samples. 9 1.4.4 Field Methods ' 9 1.4.4.1 Selection of Sample Sites 9 1.4.4.2 Collection of Water and Soil Samples. 10 1.4.4.3 Marking and Labeling Sample Sites. 10 1.4.4.4ExistingData 11 1.4.5 Analytical Methods """"""""""""""""'" 11 1.4.6Standards. 12 1.4.6.1Soil Standards. 12 1.4.6.2Water-QualityStandards 13 1.4.7 Analytical Results 13 1.5 Gallatin National Forest 14 1.5.1 History of Mining 16 1.5.1.1 Production 17 1.5.1.2Milling 18 1.6SummaryoftheGallatinNationaIForestInvestigat~on 19 1.7 Mining Districts and Drainages 20 Gallatin National Forest Drainages 20 2.1 Geology "' ' '..' ,.""...' ""." 20 2.2 EconomicGeology.
    [Show full text]
  • The Archean Geology of Montana
    THE ARCHEAN GEOLOGY OF MONTANA David W. Mogk,1 Paul A. Mueller,2 and Darrell J. Henry3 1Department of Earth Sciences, Montana State University, Bozeman, Montana 2Department of Geological Sciences, University of Florida, Gainesville, Florida 3Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana ABSTRACT in a subduction tectonic setting. Jackson (2005) char- acterized cratons as areas of thick, stable continental The Archean rocks in the northern Wyoming crust that have experienced little deformation over Province of Montana provide fundamental evidence long (Ga) periods of time. In the Wyoming Province, related to the evolution of the early Earth. This exten- the process of cratonization included the establishment sive record provides insight into some of the major, of a thick tectosphere (subcontinental mantle litho- unanswered questions of Earth history and Earth-sys- sphere). The thick, stable crust–lithosphere system tem processes: Crustal genesis—when and how did permitted deposition of mature, passive-margin-type the continental crust separate from the mantle? Crustal sediments immediately prior to and during a period of evolution—to what extent are Earth materials cycled tectonic quiescence from 3.1 to 2.9 Ga. These compo- from mantle to crust and back again? Continental sitionally mature sediments, together with subordinate growth—how do continents grow, vertically through mafi c rocks that could have been basaltic fl ows, char- magmatic accretion of plutons and volcanic rocks, acterize this period. A second major magmatic event laterally through tectonic accretion of crustal blocks generated the Beartooth–Bighorn magmatic zone assembled at continental margins, or both? Structural at ~2.9–2.8 Ga.
    [Show full text]
  • Paleontology and Stratigraphy of Upper Coniacianemiddle
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln USGS Staff -- Published Research US Geological Survey 2005 Paleontology and stratigraphy of upper Coniacianemiddle Santonian ammonite zones and application to erosion surfaces and marine transgressive strata in Montana and Alberta W. A. Cobban U.S. Geological Survey T. S. Dyman U.S. Geological Survey, [email protected] K. W. Porter Montana Bureau of Mines and Geology Follow this and additional works at: https://digitalcommons.unl.edu/usgsstaffpub Part of the Earth Sciences Commons Cobban, W. A.; Dyman, T. S.; and Porter, K. W., "Paleontology and stratigraphy of upper Coniacianemiddle Santonian ammonite zones and application to erosion surfaces and marine transgressive strata in Montana and Alberta" (2005). USGS Staff -- Published Research. 367. https://digitalcommons.unl.edu/usgsstaffpub/367 This Article is brought to you for free and open access by the US Geological Survey at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USGS Staff -- Published Research by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Cretaceous Research 26 (2005) 429e449 www.elsevier.com/locate/CretRes Paleontology and stratigraphy of upper Coniacianemiddle Santonian ammonite zones and application to erosion surfaces and marine transgressive strata in Montana and Alberta W.A. Cobban a,1, T.S. Dyman b,*, K.W. Porter c a US Geological Survey, Denver, CO 80225, USA b US Geological Survey, Denver, CO 80225, USA c Montana Bureau of Mines and Geology, Butte, MT 59701, USA Received 28 September 2004; accepted in revised form 17 January 2005 Available online 21 June 2005 Abstract Erosional surfaces are present in middle and upper Coniacian rocks in Montana and Alberta, and probably at the base of the middle Santonian in the Western Interior of Canada.
    [Show full text]
  • Comparative Study of the Economic and Business Potential of Chouteau and Teton Counties
    University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 1979 Comparative study of the economic and business potential of Chouteau and Teton counties Larry Ray Gerfen The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Gerfen, Larry Ray, "Comparative study of the economic and business potential of Chouteau and Teton counties" (1979). Graduate Student Theses, Dissertations, & Professional Papers. 5145. https://scholarworks.umt.edu/etd/5145 This Thesis is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. COMPARATIVE STUDY OF THE ECONOMIC AND BUSINESS POTENTIAL OF CHOUTEAU AND TETON COUNTIES By Larry R. Gerfen B.B.A., Baylor University, 1974 Presented in partial fulfillment of the requirements for the degree of Master of Business Administration UNIVERSITY OF MONTANA 1979 Approved by: Chai Board of Examiners Dean, Graduate School UMI Number: EP40609 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. JUM3LDissertation PaMWn® UMI EP40609 Published by ProQuest LLC (2014).
    [Show full text]
  • Postill Creek Ranch Geraldine, Montana
    POSTILL CREEK RANCH GERALDINE, MONTANA $1,800,000 | 933± ACRES LISTING AGENT: TIM MURPHY 1227 NORTH 14TH AVENUE, SUITE 1 BOZEMAN, MONTANA 59715 P: 406.587.3090 M: 406.209.0644 [email protected] POSTILL CREEK RANCH GERALDINE, MONTANA $1,800,000 | 933± ACRES LISTING AGENT: TIM MURPHY 1227 NORTH 14TH AVENUE, SUITE 1 BOZEMAN, MONTANA 59715 P: 406.587.3090 M: 406.209.0644 [email protected] Land… that’s where it all begins. Whether it is ranch land or family retreats, working cattle ranches, plantations, farms, estancias, timber or recreational ranches for sale, it all starts with the land. Since 1946, Hall and Hall has specialized in serving the owners and prospective owners of quality rural real estate by providing mortgage loans, appraisals, land management, auction and brokerage services within a unique, integrated partnership structure. Our business began by cultivating long-term relationships built upon personal service and expert counsel. We have continued to grow today by being client-focused and results-oriented—because while it all starts with the land, we know it ends with you. WITH OFFICES IN: DENVER, COLORADO BOZEMAN, MONTANA EATON, COLORADO MISSOULA, MONTANA STEAMBOAT SPRINGS, COLORADO VALENTINE, NEBRASKA SUN VALLEY, IDAHO COLLEGE STATION, TEXAS TETON VALLEY, IDAHO LAREDO, TEXAS HUTCHINSON, KANSAS LUBBOCK, TEXAS BUFFALO, WYOMING MELISSA, TEXAS BILLINGS, MONTANA SOUTHEASTERN US SALES | AUCTIONS | FINANCE | APPRAISALS | MANAGEMENT © 2020 HALL AND HALL | WWW.HALLANDHALL.COM | [email protected] — 2 — EXECUTIVE SUMMARY Postill Creek Ranch is a 933± acre mountain retreat located on the northeastern flank of the Highwood Mountains in central Montana. The Highwood Mountains are an island mountain range rising above a prairie ecosystem with fertile farmlands to over 7,600 feet in elevation.
    [Show full text]
  • University of Montana Commencement Program, 1975
    University of Montana ScholarWorks at University of Montana University of Montana Commencement Programs, 1898-2020 Office of the Registrar 6-15-1975 University of Montana Commencement Program, 1975 University of Montana (Missoula, Mont. : 1965-1994). Office of the Registrar Follow this and additional works at: https://scholarworks.umt.edu/um_commencement_programs Let us know how access to this document benefits ou.y Recommended Citation University of Montana (Missoula, Mont. : 1965-1994). Office of the Registrar, "University of Montana Commencement Program, 1975" (1975). University of Montana Commencement Programs, 1898-2020. 78. https://scholarworks.umt.edu/um_commencement_programs/78 This Program is brought to you for free and open access by the Office of the Registrar at ScholarWorks at University of Montana. It has been accepted for inclusion in University of Montana Commencement Programs, 1898-2020 by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. SEVENTY-EIGHTH ANNUAL COMMENCEMENT UNIVERSITY OF MONTANA MISSOULA SUNDAY, JUNE THE FIFTEENTH NINETEEN HUNDRED AND SEVENTY-FIVE FIELD HOUSE AUDITORIUM THE MARSHALS James H. Lowe Chairman, Faculty Senate Associate Professor of Forestry Walter L. Brown R. Keith Osterheld Professor o f English Professor of Chemistry ORDER OF EXERCISES PROCESSIONAL BRASS ENSEMBLE AND ORGAN Lance Boyd, Director John Ellis, Organ PROCESSION Marshals, the Colors, Candidates for Degrees, the Faculty, Members of the Governing Boards, Guests of Honor, the President PRESENTATION OF COLORS NATIONAL ANTHEM The Star Spangled Banner O, say! can you see by the dawn’s early light, What so proudly we hailed at the twilight’s last gleaming, Whose broad stripes and bright stars, through the perilous flight O’er the ramparts we watched, were so gallantly streaming? And the rockets’ red glare, the bombs bursting in air, Gave proof through the night that our flag was still there.
    [Show full text]
  • Quaternary and Late Tertiary of Montana: Climate, Glaciation, Stratigraphy, and Vertebrate Fossils
    QUATERNARY AND LATE TERTIARY OF MONTANA: CLIMATE, GLACIATION, STRATIGRAPHY, AND VERTEBRATE FOSSILS Larry N. Smith,1 Christopher L. Hill,2 and Jon Reiten3 1Department of Geological Engineering, Montana Tech, Butte, Montana 2Department of Geosciences and Department of Anthropology, Boise State University, Idaho 3Montana Bureau of Mines and Geology, Billings, Montana 1. INTRODUCTION by incision on timescales of <10 ka to ~2 Ma. Much of the response can be associated with Quaternary cli- The landscape of Montana displays the Quaternary mate changes, whereas tectonic tilting and uplift may record of multiple glaciations in the mountainous areas, be locally signifi cant. incursion of two continental ice sheets from the north and northeast, and stream incision in both the glaciated The landscape of Montana is a result of mountain and unglaciated terrain. Both mountain and continental and continental glaciation, fl uvial incision and sta- glaciers covered about one-third of the State during the bility, and hillslope retreat. The Quaternary geologic last glaciation, between about 21 ka* and 14 ka. Ages of history, deposits, and landforms of Montana were glacial advances into the State during the last glaciation dominated by glaciation in the mountains of western are sparse, but suggest that the continental glacier in and central Montana and across the northern part of the eastern part of the State may have advanced earlier the central and eastern Plains (fi gs. 1, 2). Fundamental and retreated later than in western Montana.* The pre- to the landscape were the valley glaciers and ice caps last glacial Quaternary stratigraphy of the intermontane in the western mountains and Yellowstone, and the valleys is less well known.
    [Show full text]