DOCSLIB.ORG

1 KECK PROPOSAL: Eocene Tectonic Evolution of the Teton-Absaroka

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
1 KECK PROPOSAL: Eocene Tectonic Evolution of the Teton-Absaroka KECK PROPOSAL: Eocene Tectonic Evolution of the Teton-Absaroka Ranges, Wyoming (Year 2) Project Leaders: John Craddock (Macalester College; [email protected]) and Dave Malone (Illinois State University; [email protected]) Host Institution: Macalester College, St. Paul, MN Project Dates: ~July 15-August 14, 2011 Student Prerequisites: Structural Geology, Sedimentology. Preamble: This project is an expansion of a 2010 Keck project that was funded at a reduced level (Craddock, 3 students); Malone and 4 students participated with separate funding. We completed or are currently working on three 2010 projects: 1. Structure, geochemistry and geochronology (U-Pb zircon) of carbonate pseudotachylite injection, White Mtn. (J. Geary, Macalester; note that this was not part of last year’s proposal but a new discovery in 2010 caused us to redirect our efforts), 2. Calcite twinning strains within the S. Fork detachment allochthon, northwest, WY (K. Kravitz, Smith; note because of a heavy snow pack in the Tetons this past summer, we chose a different structure to study), and 3. Provenance of heavy minerals and detrital zircon geochronology, Eocene Absaroka volcanics, northwest, WY (R. McGaughey, Carleton). We did not sample the footwall folds proposed in the previous proposal (under snow) and will focus on this project and mapping efforts of White Mountain and the 40 x 10 km S. Fork detachment area near Cody, WY, in part depending on the results (calcite strains, detrital zircons) of the 2010-11 effort. All seven students are working on the detrital zircon geochronology project, and two abstracts are accepted at the 2011 Denver GSA meeting. Overview: This proposal requests funding for 2 faculty to engage 6 students researching a variety of outstanding problems in the tectonic evolution of the Sevier-Laramide orogens as exposed in the Teton and Absaroka ranges in northwest Wyoming. Although the projects that we propose are quite varied in theme, it is important to note that all faculty and students will work as a group for the entire field season, and that all students will participate in at least some level on all of the projects. The Eocene was a time when the thin-skinned Sevier orogen was replaced with the thick-skinned Laramide orogen in the Cordillera, producing a variety of complex, overlapping structures. We will 1. study the strain history of footwall Paleozoic sediments overthrust by Archean gneisses in the Teton range and, 2. produce a detailed geologic map of the S. Fork detachment (SFD) allochthon exposed in the S. Fork of the Shoshone River valley, and 3. complete a geologic map of White Mtn., where we discovered 1 enormous vertical injection of carbonate pseudotachylite related to the Heart Mountain detachment in 2010. We have also included budget for detrital zircon analyses which will allow us to 1. Finish dating samples collected in 2010 (we’re on the laser in Tucson in early Nov.) or 2. Collect additional samples in 2011 depending on our results from this year, especially the White Mtn. CUC rocks (we’ve found 2 zircon populations). Introduction Orogenic shortening is accommodated by hanging wall folding above thrust faults, and the Sevier belt (late Jurassic-Eocene) records this shortening as an orderly “younging toward the craton” sequence of thrust motions with dated synorogenic sediments (Armstrong and Oriel, 1965; Dorr et al., 1977, Wiltschko and Dorr, 1983, Craddock, 1992). The transition from Sevier, east-vergent thin- skinned shortening, with 45° slab dip to the west, to west-vergent, thick-skinned shortening, occurred with decreasing slap (5°) dip in the Eocene (Bird, 1988). These crustal-scale offsets of Archean crust are dated by synorogenic deposits (Gries, 1983; DeCelles et al., 1991; Fuentes et al., 2009) and fission track studies (Roberts and Burbank, 1993; Crowley et al., 2002), and many Laramide uplifts preserve a curious peneplain surface at high elevation (Smith and Seigel, 2000). The zone of overlap between thin and thick-skinned structures is in the vicinity of Jackson Hole and the Teton Range. The Heart Mountain detachment system, arguably the largest volcanic landslide deposit (Malone, 1995 and 1996; Craddock et al., 2009; Malone and Craddock, 2008) in the world, is also an Eocene event in the vicinity of Jackson Hole and the greater Absaroka volcanic province. The South Fork detachment system is contemporaneous with the HMD event. Figure 1 is a location map with specific field sites identified; this is correlated to the student project table below (and vice versa). 2 Figure 1: Digital elevation (DEM) base of northwest Wyoming. Projects include footwall folds (1a and 1b), mapping the S. Fork detachment (2), and White Mountain (3). Proposed Projects 1. Laramide Footwall Folds (2 students) Orogenic shortening is accommodated by hangingwall folding above thrust faults. Uplift of the hangingwall ramp-anticline buries the footwall leading geologist’s to presume the footwall is undeformed. Where the footwall rocks are exposed, which is rare, the underlying sediments are usually layered parallel to the thrust with one exception, where complex folds are exposed (Craddock et al., 1985). The Laramide Fourellen fault (and Buck Mtn. fault to the south; Smith, 1991) strikes N-S and dips east along the length of the Teton Range where spectacular exposures of Archean gneisses are in thrust contact with an overturned footwall syncline in Cambrian-Mississippian sediments (Figures 2a- b). The exposures near Fourellen Peak and Alaska Basin are ideal for studying the strain history of this folded structure (N-S trend, shallow plunges). Both sandstones (quartzites; finite strains) and carbonates (calcite twin analysis on limestone and calcite veins) will preserve the deformation history around the fold curvature and along strike, and results will be compared with strain analyses nearby in the southern Cache Creek thrust sheet (Craddock et al., 1988) as well as the fold strain history of the nearby Derby Dome Laramide uplift (Craddock and Relle, 2003). We may also find syn-faulting calcite that can be 3 used to record the stress-strain field when the fault was active (Craddock et al., in review). Oriented samples will be collected throughout for thin section work on the universal stage. Each student project will include field mapping of part of the synclinal structure, sampling and measuring of fault-fold kinematic indicators, and collection of oriented samples for 3-D strain analysis. Strain analysis will involve either using 3 orthogonal oriented sections (ACF method for finite strain ellipsoids) or 1-3 oriented sections for measuring mechanical twins in calcite (limestones and veins). Fig. 2: Fourellen fault (left), with Archean gneisses over the Cambrian-Pennsylvanian section (photo from Love et al., 2007) and, right, the trace of the same fault placing Archean gneisses over the Cambrian Flathead Sandstone (circled) on the west side of the Teton’s (photo from Smith, 1991). 2. South Fork Detachment Strains and Mapping (2 students) The Heart Mountain Detachment in northwest Wyoming has been the focus of scientific inquiry for more than 100 years. The lesser known South Fork detachment, which is temporally and spatially related to the Heart Mountain detachment, has had much less attention over the years. The South Fork detachment (SFD) is exposed in the drainage of the South Fork of the Shoshone River and along Rattlesnake Creek. Dake (1918) initially described and named the SFF and Pierce further defined and mapped its extent (Pierce, 1957, 1966, 1970; Pierce and Nelson, 1968, 1969). Bucher (1936) first suggested gravity as a driving mechanism for movement and formation of this 10 X 40 km rootless, folded structure (Fig. 3). 4 Figure 3: Geologic map of the South Fork Detachment area (from Love and Christianson, 1985, above), and and air photo composite (1”=10 km) of the S. Fork detachment southwest of Cody, WY. The decollement surface is at the base of the Jurassic Sundance Formation. It ramps up section to the Cretaceous Cody Shale, and ramps once again up section to the Eocene Willwood Formation. The South Fork detachment is obscured by younger volcanic rocks to the west and south. As much as 10 km of displacement is indicated and the hanging wall structures (folds) are oriented SW‐NE with shallow plunges. Some bedding is overturned, indicating nappe‐ 5 like folds, in association with “circular” faults (Fig. 4). Although the motion direction of the South Fork fault seems to align with the presumed displacement direction the Heart Mountain slide block (to the SE), the orientation of pre‐ Cenozoic rocks in the lower plate and those to the southeast and southwest of the upper plate of the fault are consistent with the variable pattern of E‐W Sevier‐ Laramide shortening. The South Fork detachment has been interpreted to be the front of a gravity detachment that is older than and unrelated to the Heart Mountain Detachment (Blackstone, 1985; and Pierce, 1957, 1986), the easternmost expression of the Cordilleran overthrust belt (Clarey, 1990), or the toe of the Heart Mountain detachment (Beutner and Hauge 2009). The data supporting either interpretation are so poorly constrained that new detailed mapping of critical exposures is warranted. Most of the reinterpretations used by Clarey, Beutner, and Hauge used existing mapping of Pierce and his colleagues, which has been called into question by all of the workers in the area for the past 30+ years. The principal scientific question advanced with this subproject is: Does the new detailed geometric (through geologic mapping) and kinematic (through calcite strain analysis) advance the Sevier‐Laramide shortening or the Heart Mountain‐related gravity slide hypothesis? Mapping done as part of this project will be at the 1:24,000 scale on modern base maps in the Twin Creek and Belknap Creek 7.5 Minute Quadrangles. Reconnaissance mapping will be conducted in critical surrounding areas.
Load more

Recommended publications
  • WPLI Resolution
    Matters from Staff Agenda Item # 17 Board of County Commissioners ‐ Staff Report Meeting Date: 11/13/2018 Presenter: Alyssa Watkins Submitting Dept: Administration Subject: Consideration of Approval of WPLI Resolution Statement / Purpose: Consideration of a resolution proclaiming conservation principles for US Forest Service Lands in Teton County as a final recommendation of the Wyoming Public Lands Initiative (WPLI) process. Background / Description (Pros & Cons): In 2015, the Wyoming County Commissioners Association (WCCA) established the Wyoming Public Lands Initiative (WPLI) to develop a proposed management recommendation for the Wilderness Study Areas (WSAs) in Wyoming, and where possible, pursue other public land management issues and opportunities affecting Wyoming’s landscape. In 2016, Teton County elected to participate in the WPLI process and appointed a 21‐person Advisory Committee to consider the Shoal Creek and Palisades WSAs. Committee meetings were facilitated by the Ruckelshaus Institute (a division of the University of Wyoming’s Haub School of Environment and Natural Resources). Ultimately the Committee submitted a number of proposals, at varying times, to the BCC for consideration. Although none of the formal proposals submitted by the Teton County WPLI Committee were advanced by the Board of County Commissioners, the Board did formally move to recognize the common ground established in each of the Committee’s original three proposals as presented on August 20, 2018. The related motion stated that the Board chose to recognize as a resolution or as part of its WPLI recommendation, that all members of the WPLI advisory committee unanimously agree that within the Teton County public lands, protection of wildlife is a priority and that there would be no new roads, no new timber harvest except where necessary to support healthy forest initiatives, no new mineral extraction excepting gravel, no oil and gas exploration or development.
    [Show full text]
  • Teton Range Bighorn Sheep Herd Situation Assessment January 2020
    Teton Range Bighorn Sheep Herd Situation Assessment January 2020 Photo: A. Courtemanch Compiled by: Teton Range Bighorn Sheep Working Group Table of Contents EXECUTIVE SUMMARY ............................................................................................................ 2 Introduction and Overview .................................................................................................... 2 Assessment Process ................................................................................................................. 2 Key Findings: Research Summary and Expert Panel ......................................................... 3 Key Findings: Community Outreach Efforts ....................................................................... 4 Action Items .............................................................................................................................. 4 INTRODUCTION AND BACKGROUND ............................................................................... 6 Purpose of this Assessment .................................................................................................... 6 Background ............................................................................................................................... 6 ASSESSMENT APPROACH....................................................................................................... 6 PART 1: Research Summary and Expert Panel ................................................................... 6 Key Findings: Research Summary
    [Show full text]
  • WYOMING Adventure Guide from YELLOWSTONE NATIONAL PARK to WILD WEST EXPERIENCES
    WYOMING adventure guide FROM YELLOWSTONE NATIONAL PARK TO WILD WEST EXPERIENCES TravelWyoming.com/uk • VisitTheUsa.co.uk/state/wyoming • +1 307-777-7777 WIND RIVER COUNTRY South of Yellowstone National Park is Wind River Country, famous for rodeos, cowboys, dude ranches, social powwows and home to the Eastern Shoshone and Northern Arapaho Indian tribes. You’ll find room to breathe in this playground to hike, rock climb, fish, mountain bike and see wildlife. Explore two mountain ranges and scenic byways. WindRiver.org CARBON COUNTY Go snowmobiling and cross-country skiing or explore scenic drives through mountains and prairies, keeping an eye out for foxes, coyotes, antelope and bald eagles. In Rawlins, take a guided tour of the Wyoming Frontier Prison and Museum, a popular Old West attraction. In the quiet town of Saratoga, soak in famous mineral hot springs. WyomingCarbonCounty.com CODY/YELLOWSTONE COUNTRY Visit the home of Buffalo Bill, an American icon, at the eastern gateway to Yellowstone National Park. See wildlife including bears, wolves and bison. Discover the Wild West at rodeos and gunfight reenactments. Hike through the stunning Absaroka Mountains, ride a mountain bike on the “Twisted Sister” trail and go flyfishing in the Shoshone River. YellowstoneCountry.org THE WORT HOTEL A landmark on the National Register of Historic Places, The Wort Hotel represents the Western heritage of Jackson Hole and its downtown location makes it an easy walk to shops, galleries and restaurants. Awarded Forbes Travel Guide Four-Star Award and Condé Nast Readers’ Choice Award. WortHotel.com welcome to Wyoming Lovell YELLOWSTONE Powell Sheridan BLACK TO YELLOW REGION REGION Cody Greybull Bu alo Gillette 90 90 Worland Newcastle 25 Travel Tips Thermopolis Jackson PARK TO PARK GETTING TO KNOW WYOMING REGION The rugged Rocky Mountains meet the vast Riverton Glenrock Lander High Plains (high-elevation prairie) in Casper Douglas SALT TO STONE Wyoming, which encompasses 253,348 REGION ROCKIES TO TETONS square kilometres in the western United 25 REGION States.
    [Show full text]
  • Chapter 17. Quartzite Gravel Northwest Wyoming
    Chapter 17 Quartzite Gravel of Northwest Wyoming The quartzites of southwest Montana and adjacent Idaho extend eastward into Wyoming1 in a semi-continuous belt, as shown on Figure 16.1 of the previous chapter. This chapter will describe those deposits. Quartzite Gravel Lag John Hergenrather and I have found scattered surficial quartzites from near Interstate 15 in northeastern Idaho, just south of Lima, Montana, eastward to the northern Teton Mountains and over a four-wheel drive pass between Yellowstone and Grand Teton National Parks. These quartzites seem to have mostly formed a thin layer or lag deposit on the surface or were reworked by local mountain glaciation. This lag rep- resents the red hashed area in Figure 16.1. Quartzites on Top of the Northern Teton Mountains Probably the most fascinating quartz- ite location is on top of the northern Teton Mountains! Brent Carter and I took a Figure 17.1. Slightly dipping limestone at the top three day round trip hike to the top of Red of Red Mountain. Mountain in the northern Teton Moun- tains, 10,177 feet (3,102 m) msl!2,3 Red Mountain and Mount Moran (12,605 feet, 3,842 m msl) represent remnants of a flat-topped planation surface.2 Red Mountain is composed of slightly tilted limestones (Figure 17.1), while Mount Moran is composed of granite or gneiss with a 50-foot (15 m) thick cap of Flathead Sandstone on top (see Figure 33.7). The quartzites on top of Red Mountain are mainly a thin lag mixed with angular lime- stone cobbles and boulders (Figure 17.2).
    [Show full text]
  • GEOHYDROLOGY of TERTIARY ROCKS in the GREEN RIVER STRUCTURAL BASIN in WYOMING, UTAH, and COLORADO by Lawrence J
    GEOHYDROLOGY OF TERTIARY ROCKS IN THE GREEN RIVER STRUCTURAL BASIN IN WYOMING, UTAH, AND COLORADO by Lawrence J. Martin U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 92-4164 Prepared in cooperation with the WYOMING STATE ENGINEER Cheyenne, Wyoming 1996 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director The use of trade, product, industry, or firm names i$ for descriptive purposes only and does not imply endorsement by thelU.S. Government. For additional information Copies of this report can be write to: purchased from: District Chief U.S. Geological Survey U.S. Geological Survey, WRD Branch of Information Services 2617 E. Lincolnway, Suite B Box 25286, Denver Federal Center Cheyenne, Wyoming 82001-5662 Denver, Colorado 80225 CONTENTS Page Abstract ................................................................................................................................................................................ 1 Introduction .......................................................................................................................................................................... 1 Purpose and scope .................................................................................................................................................... 3 Criteria for data selection ......................................................................................................................................... 3 Previous investigations ............................................................................................................................................
    [Show full text]
  • Bridger-Teton National Forest Evaluation of Areas with Wilderness Potential
    BTNF Evaluation of Areas with Wilderness Potential 2008 BRIDGER-TETON NATIONAL FOREST EVALUATION OF AREAS WITH WILDERNESS POTENTIAL Phillips Ridge Roadless Area 9/23/2009 1 CONTENTS Introduction ..................................................................................................................................2 The 2001 roadless rule, areas with wilderness potential, and process for integration .................2 Capability factors defined ............................................................................................................4 Availability defined .....................................................................................................................9 Need defined ................................................................................................................................9 BTNF areas with wilderness potential .........................................................................................11 Eligibility factors by area .............................................................................................................15 Summary of capability factors .....................................................................................................68 Areas with Wilderness potential and Forest Plan revision ..........................................................70 INTRODUCTION Roadless areas were identified during the Roadless Area Review and Evaluation II (RARE II) analysis conducted in 1978 and re-evaluated in 1983 to include all areas of at least
    [Show full text]
  • Fen Mapping for the Bridger-Teton National Forest
    Fen Mapping for the Bridger-Teton National Forest November 2018 CNHP’s mission is to preserve the natural diversity of life by contributing the essential scientific foundation that leads to lasting conservation of Colorado's biological wealth. Colorado Natural Heritage Program Warner College of Natural Resources Colorado State University 1475 Campus Delivery Fort Collins, CO 80523 Report Prepared for: Bridger-Teton National Forest 340 N. Cache Jackson, WY 83001 Recommended Citation: Smith, G. and J. Lemly. 2018. Fen Mapping for the Bridger-Teton National Forest. Colorado Natural Heritage Program, Colorado State University, Fort Collins, Colorado. Front Cover: © Colorado Natural Heritage Program Fen Mapping for the Bridger-Teton National Forest Gabrielle Smith and Joanna Lemly Colorado Natural Heritage Program Warner College of Natural Resources Colorado State University Fort Collins, Colorado 80523 November 2018 Page intentionally left blank. EXECUTIVE SUMMARY The Bridger-Teton National Forest (BTNF) covers 3.4 million acres within the Upper Green and Snake Headwaters River Basins in northwest Wyoming. The diverse geography of the BTNF creates an equally diverse set of wetlands that provide important ecological services to both BTNF and lands downstream. Organic soil wetlands known as fens are an irreplaceable resource that the U.S. Forest Service has determined should be managed for conservation and restoration. Fens are defined as groundwater-fed wetlands with organic soils that typically support sedges and low stature shrubs. In the arid west, organic soil formation can take thousands of years. Long-term maintenance of fens requires maintenance of both the hydrology and the plant communities that enable fen formation. In 2012, the U.S.
    [Show full text]
  • Eocene Green River Formation, Western United States
    Synoptic reconstruction of a major ancient lake system: Eocene Green River Formation, western United States M. Elliot Smith* Alan R. Carroll Brad S. Singer Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA ABSTRACT Members. Sediment accumulation patterns than being confi ned to a single episode of arid thus refl ect basin-center–focused accumula- climate. Evaporative terminal sinks were Numerous 40Ar/39Ar experiments on sani- tion rates when the basin was underfi lled, initially located in the Greater Green River dine and biotite from 22 ash beds and 3 and supply-limited accumulation when the and Piceance Creek Basins (51.3–48.9 Ma), volcaniclastic sand beds from the Greater basin was balanced fi lled to overfi lled. Sedi- then gradually migrated southward to the Green River, Piceance Creek, and Uinta ment accumulation in the Uinta Basin, at Uinta Basin (47.1–45.2 Ma). This history is Basins of Wyoming, Colorado, and Utah Indian Canyon, Utah, was relatively con- likely related to progressive southward con- constrain ~8 m.y. of the Eocene Epoch. Mul- stant at ~150 mm/k.y. during deposition of struction of the Absaroka Volcanic Prov- tiple analyses were conducted per sample over 5 m.y. of both evaporative and fl uctuat- ince, which constituted a major topographic using laser fusion and incremental heating ing profundal facies, which likely refl ects the and thermal anomaly that contributed to a techniques to differentiate inheritance, 40Ar basin-margin position of the measured sec- regional north to south hydrologic gradient. loss, and 39Ar recoil.
    [Show full text]
  • Water Development Office 6920 YELLOWTAIL ROAD TELEPHONE: (307) 777-7626 CHEYENNE, WY 82002 FAX: (307) 777-6819 TECHNICAL MEMORANDUM
    THE STATE OF WYOMING Water Development Office 6920 YELLOWTAIL ROAD TELEPHONE: (307) 777-7626 CHEYENNE, WY 82002 FAX: (307) 777-6819 TECHNICAL MEMORANDUM TO: Water Development Commission DATE: December 13, 2013 FROM: Keith E. Clarey, P.G. REFERENCE: Snake/Salt River Basin Plan Update, 2012 SUBJECT: Available Groundwater Determination – Tab XI (2012) Contents 1.0 Introduction .............................................................................................................................. 1 2.0 Hydrogeology .......................................................................................................................... 4 3.0 Groundwater Development .................................................................................................... 15 4.0 Groundwater Quality ............................................................................................................. 21 5.0 Geothermal Resources ........................................................................................................... 22 6.0 Groundwater Availability ...................................................................................................... 22 References ..................................................................................................................................... 23 Appendix A: Figures and Table ....................................................................................................... i 1.0 Introduction This 2013 Technical Memorandum is an update of the September 10, 2003,
    [Show full text]
  • Attachment J Assessment of Existing Paleontologic Data Along with Field Survey Results for the Jonah Field
    Attachment J Assessment of Existing Paleontologic Data Along with Field Survey Results for the Jonah Field June 12, 2007 ABSTRACT This is compilation of a technical analysis of existing paleontological data and a limited, selective paleontological field survey of the geologic bedrock formations that will be impacted on Federal lands by construction associated with energy development in the Jonah Field, Sublette County, Wyoming. The field survey was done on approximately 20% of the field, primarily where good bedrock was exposed or where there were existing, debris piles from recent construction. Some potentially rich areas were inaccessible due to biological restrictions. Heavily vegetated areas were not examined. All locality data are compiled in the separate confidential appendix D. Uinta Paleontological Associates Inc. was contracted to do this work through EnCana Oil & Gas Inc. In addition BP and Ultra Resources are partners in this project as they also have holdings in the Jonah Field. For this project, we reviewed a variety of geologic maps for the area (approximately 47 sections); none of maps have a scale better than 1:100,000. The Wyoming 1:500,000 geology map (Love and Christiansen, 1985) reveals two Eocene geologic formations with four members mapped within or near the Jonah Field (Wasatch – Alkali Creek and Main Body; Green River – Laney and Wilkins Peak members). In addition, Winterfeld’s 1997 paleontology report for the proposed Jonah Field II Project was reviewed carefully. After considerable review of the literature and museum data, it became obvious that the portion of the mapped Alkali Creek Member in the Jonah Field is probably misinterpreted.
    [Show full text]
  • To Kill Or Not to Kill? Managing Charismatic Ungulates in the Tetons
    To Kill or Not to Kill? Managing charismatic ungulates in the Tetons The wording of this article has been adjusted to a 7-8th grade reading level. Andrea Barbknecht of the Wyoming Wildlife Federation made the revisions as part of the organization’s curricula to engage kids in exploring their Wyoming landscape. The original article, written by Emily Reed for Western Confluence magazine, can be found here. By Emily Reed (May 2020) Michael Whitfield tells a story about the Now, 30 years later, that exact situation has first time he saw bighorn sheep in the high occurred. Mountain goats have established country. He stood on a ridgeline in the a breeding population in the Teton Range. shadow of the Teton Range and watched a Meanwhile, the bighorn sheep herd is group grazing along a plateau. As he snuck declining. Managers now face a decision up to get a closer look, “the about how to manage both species. sheep…disappeared right into the cliffs…and then they were gone,” he says. Whitfield spent most summers in the 1980s chasing these high-country sheep. He followed them across cliff faces through harsh weather for his graduate research. At the time, nobody knew much about the Teton sheep except that they seemed to be declining fast. Over years of field work in the high country, Two bighorn rams are some of the few last remaining Whitfield discovered a small, isolated members of the iconic Teton herd, which has remained population of bighorn sheep. They were intact, if diminished, while other herds around the West blinked out.
    [Show full text]
  • Status of Plant Species of Special Concern in US Forest Service
    Status of Plant Species of Special Concern In US Forest Service Region 4 In Wyoming Report prepared for the US Forest Service By Walter Fertig Wyoming Natural Diversity Database University of Wyoming PO Box 3381 Laramie, WY 82071 20 January 2000 INTRODUCTION The US Forest Service is directed by the Endangered Species Act (ESA) and internal policy (through the Forest Service Manual) to manage for listed and candidate Threatened and Endangered plant species on lands under its jurisdiction. The Intermountain Region of the Forest Service (USFS Region 4) has developed a Sensitive species policy to address the management needs of rare plants that might qualify for listing under the ESA (Joslin 1994). The objective of this policy is to prevent Forest Service actions from contributing to the further endangerment of Sensitive species and their subsequent listing under the ESA. In addition, the Forest Service is required to manage for other rare species and biological diversity under provisions of the National Forest Management Act. The current Sensitive plant species list for Region 4 (covering Ashley, Bridger-Teton, Caribou, Targhee, and Wasatch-Cache National Forests and Flaming Gorge National Recreation Area in Wyoming) was last revised in 1994 (Joslin 1994). Field studies by botanists with the Forest Service, Rocky Mountain Herbarium, Wyoming Natural Diversity Database (WYNDD), and private consulting firms since 1994 have shown that several currently listed species may no longer warrant Sensitive designation, while some new species should be considered for listing. Region 4 is currently reviewing its Sensitive plant list and criteria for listing. This report has been prepared to provide baseline information on the statewide distribution and abundance of 127 plants listed as “species of special concern” by WYNDD (Table 1) (Fertig and Beauvais 1999).
    [Show full text]