Mountain Views Vol. 6, No. 2
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Two Contrasting Phanerozoic Orogenic Systems Revealed by Hafnium Isotope Data William J
ARTICLES PUBLISHED ONLINE: 17 APRIL 2011 | DOI: 10.1038/NGEO1127 Two contrasting Phanerozoic orogenic systems revealed by hafnium isotope data William J. Collins1*(, Elena A. Belousova2, Anthony I. S. Kemp1 and J. Brendan Murphy3 Two fundamentally different orogenic systems have existed on Earth throughout the Phanerozoic. Circum-Pacific accretionary orogens are the external orogenic system formed around the Pacific rim, where oceanic lithosphere semicontinuously subducts beneath continental lithosphere. In contrast, the internal orogenic system is found in Europe and Asia as the collage of collisional mountain belts, formed during the collision between continental crustal fragments. External orogenic systems form at the boundary of large underlying mantle convection cells, whereas internal orogens form within one supercell. Here we present a compilation of hafnium isotope data from zircon minerals collected from orogens worldwide. We find that the range of hafnium isotope signatures for the external orogenic system narrows and trends towards more radiogenic compositions since 550 Myr ago. By contrast, the range of signatures from the internal orogenic system broadens since 550 Myr ago. We suggest that for the external system, the lower crust and lithospheric mantle beneath the overriding continent is removed during subduction and replaced by newly formed crust, which generates the radiogenic hafnium signature when remelted. For the internal orogenic system, the lower crust and lithospheric mantle is instead eventually replaced by more continental lithosphere from a collided continental fragment. Our suggested model provides a simple basis for unravelling the global geodynamic evolution of the ancient Earth. resent-day orogens of contrasting character can be reduced to which probably began by the Early Ordovician12, and the Early two types on Earth, dominantly accretionary or dominantly Paleozoic accretionary orogens in the easternmost Altaids of Pcollisional, because only the latter are associated with Wilson Asia13. -
Climate Change May Induce Connectivity Loss and Mountaintop Extinction in Central American Forests ✉ Lukas Baumbach 1 , Dan L
ARTICLE https://doi.org/10.1038/s42003-021-02359-9 OPEN Climate change may induce connectivity loss and mountaintop extinction in Central American forests ✉ Lukas Baumbach 1 , Dan L. Warren 2, Rasoul Yousefpour1 & Marc Hanewinkel 1 The tropical forests of Central America serve a pivotal role as biodiversity hotspots and provide ecosystem services securing human livelihood. However, climate change is expected to affect the species composition of forest ecosystems, lead to forest type transitions and trigger irrecoverable losses of habitat and biodiversity. Here, we investigate potential impacts of climate change on the environmental suitability of main plant functional types (PFTs) across Central America. Using a large database of occurrence records and physiological data, 1234567890():,; we classify tree species into trait-based groups and project their suitability under three representative concentration pathways (RCPs 2.6, 4.5 and 8.5) with an ensemble of state-of- the-art correlative modelling methods. Our results forecast transitions from wet towards generalist or dry forest PFTs for large parts of the study region. Moreover, suitable area for wet-adapted PFTs is projected to latitudinally diverge and lose connectivity, while expected upslope shifts of montane species point to high risks of mountaintop extinction. These findings underline the urgent need to safeguard the connectivity of habitats through biological corridors and extend protected areas in the identified transition hotspots. 1 Chair of Forestry Economics and Forest Planning, -
Castle Crags State Park Brochure
Our Mission The mission of California State Parks is Castle Crags to provide for the health, inspiration and education of the people of California by helping he lofty spires and to preserve the state’s extraordinary biological T State Park diversity, protecting its most valued natural and granite dome of Castle Crags cultural resources, and creating opportunities for high-quality outdoor recreation. rise to more than 6,500 feet. The grandeur of the crags has been revered as California State Parks supports equal access. an extraordinary place Prior to arrival, visitors with disabilities who need assistance should contact the park for millennia. at (530) 235-2684. This publication can be made available in alternate formats. Contact [email protected] or call (916) 654-2249. CALIFORNIA STATE PARKS P.O. Box 942896 Sacramento, CA 94296-0001 For information call: (800) 777-0369 (916) 653-6995, outside the U.S. 711, TTY relay service www.parks.ca.gov Discover the many states of California.™ Castle Crags State Park 20022 Castle Creek Road Castella, CA 96017 (530) 235-2684 © 2014 California State Parks M ajestic Castle Crags have inspired The Okwanuchu Shasta territory covered A malaria epidemic brought by European fur enduring myths and legends since about 700 square miles of forested mountains trappers wiped out much of the Okwanuchu prehistoric times. More than 170 million from the headwaters of the Sacramento River Shasta populace by 1833. years old, these granite formations in to the McCloud River and from Mount Shasta With the 1848 gold discoveries at the the Castle Crags Wilderness border the to Pollard Flat. -
Geologic Map of the Frisco Quadrangle, Summit County, Colorado
Geologic Map of the Frisco Quadrangle, Summit County, Colorado By Karl S. Kellogg, Paul J. Bartos, and Cindy L. Williams Pamphlet to accompany MISCELLANEOUS FIELD STUDIES MAP MF-2340 2002 U.S. Department of the Interior U.S. Geological Survey Geologic Map of the Frisco Quadrangle, Summit County, Colorado By Karl S. Kellogg, Paul J. Bartos, and Cindy L. Williams DESCRIPTION OF MAP UNITS af Artificial fill (recent)—Compacted and uncompacted rock fragments and finer material underlying roadbed and embankments along and adjacent to Interstate 70. Also includes material comprising Dillon Dam dt Dredge tailings (recent)—Unconsolidated, clast-supported deposits containing mostly well- rounded to subrounded, cobble- to boulder-size clasts derived from dredging of alluvium for gold along the Blue and Swan Rivers; similar dredge tailings along Gold Run Gulch are too small to show on map. Dredge tailings were mapped from 1974 air photos; most tailings have now been redistributed and leveled for commercial development Qal Alluvium (Holocene)—Unconsolidated clast-supported deposits containing silt- to boulder-size, moderately sorted to well-sorted clasts in modern floodplains; includes overbank deposits. Clasts are as long as 1 m in Blue River channel; clasts are larger in some side-stream channels. Larger clasts are moderately rounded to well rounded. Includes some wetland deposits in and adjacent to beaver ponds along Ryan Gulch. Maximum thickness unknown, but greater than 10 m in Blue River channel Qw Wetland deposits (Holocene)—Dark-brown to black, organic-rich sediment underlying wetland areas, commonly containing standing water and dense willow stands. Maximum thickness estimated to be about 15 m Qav Avalanche deposits (Holocene)—Unsorted, unstratified hummocky deposits at the distal ends of avalanche-prone hillside in Sec. -
Inyo National Forest Visitor Guide
>>> >>> Inyo National Forest >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> Visitor Guide >>> >>> >>> >>> >>> $1.00 Suggested Donation FRED RICHTER Inspiring Destinations © Inyo National Forest Facts “Inyo” is a Paiute xtending 165 miles Bound ary Peak, South Si er ra, lakes and 1,100 miles of streams Indian word meaning along the California/ White Mountain, and Owens River that provide habitat for golden, ENevada border between Headwaters wildernesses. Devils brook, brown and rainbow trout. “Dwelling Place of Los Angeles and Reno, the Inyo Postpile Nation al Mon ument, Mam moth Mountain Ski Area National Forest, established May ad min is tered by the National Park becomes a sum mer destination for the Great Spirit.” 25, 1907, in cludes over two million Ser vice, is also located within the mountain bike en thu si asts as they acres of pris tine lakes, fragile Inyo Na tion al For est in the Reds ride the chal leng ing Ka mi ka ze Contents Trail from the top of the 11,053-foot mead ows, wind ing streams, rugged Mead ow area west of Mam moth Wildlife 2 Sierra Ne va da peaks and arid Great Lakes. In addition, the Inyo is home high Mam moth Moun tain or one of Basin moun tains. El e va tions range to the tallest peak in the low er 48 the many other trails that transect Wildflowers 3 from 3,900 to 14,494 feet, pro vid states, Mt. Whitney (14,494 feet) the front coun try of the forest. Wilderness 4-5 ing diverse habitats that sup port and is adjacent to the lowest point Sixty-five trailheads provide Regional Map - North 6 vegetation patterns ranging from in North America at Badwater in ac cess to over 1,200 miles of trail Mono Lake 7 semiarid deserts to high al pine Death Val ley Nation al Park (282 in the 1.2 million acres of wil der- meadows. -
Martian Crater Morphology
ANALYSIS OF THE DEPTH-DIAMETER RELATIONSHIP OF MARTIAN CRATERS A Capstone Experience Thesis Presented by Jared Howenstine Completion Date: May 2006 Approved By: Professor M. Darby Dyar, Astronomy Professor Christopher Condit, Geology Professor Judith Young, Astronomy Abstract Title: Analysis of the Depth-Diameter Relationship of Martian Craters Author: Jared Howenstine, Astronomy Approved By: Judith Young, Astronomy Approved By: M. Darby Dyar, Astronomy Approved By: Christopher Condit, Geology CE Type: Departmental Honors Project Using a gridded version of maritan topography with the computer program Gridview, this project studied the depth-diameter relationship of martian impact craters. The work encompasses 361 profiles of impacts with diameters larger than 15 kilometers and is a continuation of work that was started at the Lunar and Planetary Institute in Houston, Texas under the guidance of Dr. Walter S. Keifer. Using the most ‘pristine,’ or deepest craters in the data a depth-diameter relationship was determined: d = 0.610D 0.327 , where d is the depth of the crater and D is the diameter of the crater, both in kilometers. This relationship can then be used to estimate the theoretical depth of any impact radius, and therefore can be used to estimate the pristine shape of the crater. With a depth-diameter ratio for a particular crater, the measured depth can then be compared to this theoretical value and an estimate of the amount of material within the crater, or fill, can then be calculated. The data includes 140 named impact craters, 3 basins, and 218 other impacts. The named data encompasses all named impact structures of greater than 100 kilometers in diameter. -
(1987): "Tectonomagmatic Evolution of Cenozoic Extension in the North American Cordillera"
Downloaded from http://sp.lyellcollection.org/ by Frances J Cooper on January 21, 2013 Geological Society, London, Special Publications Tectonomagmatic evolution of Cenozoic extension in the North American Cordillera Brian P. Wernicke, Philip C. England, Leslie J. Sonder and Robert L. Christiansen Geological Society, London, Special Publications 1987, v.28; p203-221. doi: 10.1144/GSL.SP.1987.028.01.15 Email alerting click here to receive free e-mail alerts when service new articles cite this article Permission click here to seek permission to re-use all or request part of this article Subscribe click here to subscribe to Geological Society, London, Special Publications or the Lyell Collection Notes © The Geological Society of London 2013 Downloaded from http://sp.lyellcollection.org/ by Frances J Cooper on January 21, 2013 Tectonomagmatic evolution of Cenozoic extension in the North American Cordillera B.P. Wernicke, R.L. Christiansen, P.C. England & L.J. Sonder SUMMARY: The spatial and temporal distributions of Cenozoic extension and magmatism in the Cordillera suggest that the onset of major crustal extension at a particular latitude was confined to a relatively narrow belt (< 100 km, pre-extension) and followed the onset of intermediate and silicic magmatism by no more than a few million years. Extension began in early Eocene time in southern British Columbia, northern Washington, Idaho and Montana. Farther S, extension began at about the Eocene- Oligocene boundary in the Great Basin and slightly later in the Mojave-Sonora Desert region. The intervening area, at the latitude of Las Vegas, remained quiescent until mid- Miocene time. Compositional and isotopic characteristics of most pre-Miocene magmas are consistent with their containing major components of melted continental crust. -
Matthew Greene Were Starting to Understand the Grave the Following Day
VANISHED An account of the mysterious disappearance of a climber in the Sierra Nevada BY MONICA PRELLE ILLUSTRATIONS BY BRETT AFFRUNTI CLIMBING.COM — 61 VANISHED Three months earlier in July, the 39-year-old high school feasted on their arms. They went hiking together often, N THE SMALL SKI TOWN of Mammoth Lakes in math teacher dropped his car off at a Mammoth auto shop even in the really cold winters common to the Northeast. California’s Eastern Sierra, the first snowfall of the for repairs. He was visiting the area for a summer climb- “The ice didn’t slow him down one bit,” Minto said. “I strug- ing vacation when the car blew a head gasket. The friends gled to keep up.” Greene loved to run, competing on the track year is usually a beautiful and joyous celebration. Greene was traveling with headed home as scheduled, and team in high school and running the Boston Marathon a few Greene planned to drive to Colorado to join other friends times as an adult. As the student speaker for his high school But for the family and friends of a missing for more climbing as soon as his car was ready. graduation, Greene urged his classmates to take chances. IPennsylvania man, the falling flakes in early October “I may have to spend the rest of my life here in Mam- “The time has come to fulfill our current goals and to set moth,” he texted to a friend as he got more and more frus- new ones to be conquered later,” he said in his speech. -
The High Deccan Duricrusts of India and Their Significance for the 'Laterite
The High Deccan duricrusts of India and their significance for the ‘laterite’ issue Cliff D Ollier1 and Hetu C Sheth2,∗ 1School of Earth and Geographical Sciences, The University of Western Australia, Nedlands, W.A. 6009, Australia. 2Department of Earth Sciences, Indian Institute of Technology (IIT) Bombay, Powai, Mumbai 400 076, India. ∗e-mail: [email protected] In the Deccan region of western India ferricrete duricrusts, usually described as laterites, cap some basalt summits east of the Western Ghats escarpment, basalts of the low-lying Konkan Plain to its west, as well as some sizeable isolated basalt plateaus rising from the Plain. The duricrusts are iron-cemented saprolite with vermiform hollows, but apart from that have little in common with the common descriptions of laterite. The classical laterite profile is not present. In particular there are no pisolitic concretions, no or minimal development of con- cretionary crust, and the pallid zone, commonly assumed to be typical of laterites, is absent. A relatively thin, non-indurated saprolite usually lies between the duricrust and fresh basalt. The duricrust resembles the classical laterite of Angadippuram in Kerala (southwestern India), but is much harder. The High Deccan duricrusts capping the basalt summits in the Western Ghats have been interpreted as residuals from a continuous (but now largely destroyed) laterite blan- ket that represents in situ transformation of the uppermost lavas, and thereby as marking the original top of the lava pile. But the unusual pattern of the duricrusts on the map and other evidence suggest instead that the duricrusts formed along a palaeoriver system, and are now in inverted relief. -
Stanford Alpine Club Journal, 1958
STANFORD ALPINE CLUB JOURNAL 1958 STANFORD, CALIFORNIA i-., r ' j , / mV « Club Officers 1956-57 John Harlin, President John Mathias, Vice President Karl Hufbauer, Secretary William Pope, Treasurer 1957-58 Michael Roberts, President Karl Hufbauer, Vice-President Sidney Whaley, Secretary- Ivan Weightman, Treasurer ADVISORY COUNCIL John Maling, Chairman Winslow Briggs Henry Kendall Hobey DeStaebler Journal Staff Michael Roberts, Editor Henry Kendall, Photography Sidney Whaley Lenore Lamb Contents First Ascent of the East Peak of Mount Logan 1 Out of My Journal (Peru, 1955) 10 Battle Range, 1957 28 The SAC Trans-Sierra Tour 40 Climbing Notes 51 frontispiece: Dave Sowles enroute El Cafitan Tree, Yosemite Valley. Photo by Henry Kendall Grateful acknowledgement is made to the following: Mr. Richard Keeble, printing consultant Badger Printing Co., Appleton, Wise., photographic plates, press work and binding. Miss Mary Vogel, Appleton, Wise., composition and printing of text. Fox River Paper Corporation, Appleton, Wise., paper for text and photographs. FIRST ASCENT OF THE EAST PEAK OF MOUNT LOGAN by GILBERT ROBERTS Mount Logon. North America's second highest peak at 19,850 feet, is also one of the world's largest mountain masses. Located in the wildest part of the St. Elias Range, it has seen little mountaineering activity. In 1925, the first ascent was accomplished by a route from the Ogilvie Glacier which gained the long ridge leading to the summit from King Col. This ascent had gone down as one of the great efforts in mountaineering history. McCarthy, Foster, Lambert, Carpe, Read, and Taylor ulti- mately reached the central summit after months of effort including the relaying of loads by dog sled in the long Yukon winter--a far cry from the age of the air drop. -
Washington State's Scenic Byways & Road Trips
waShington State’S Scenic BywayS & Road tRipS inSide: Road Maps & Scenic drives planning tips points of interest 2 taBLe of contentS waShington State’S Scenic BywayS & Road tRipS introduction 3 Washington State’s Scenic Byways & Road Trips guide has been made possible State Map overview of Scenic Byways 4 through funding from the Federal Highway Administration’s National Scenic Byways Program, Washington State Department of Transportation and aLL aMeRican RoadS Washington State Tourism. waShington State depaRtMent of coMMeRce Chinook Pass Scenic Byway 9 director, Rogers Weed International Selkirk Loop 15 waShington State touRiSM executive director, Marsha Massey nationaL Scenic BywayS Marketing Manager, Betsy Gabel product development Manager, Michelle Campbell Coulee Corridor 21 waShington State depaRtMent of tRanSpoRtation Mountains to Sound Greenway 25 Secretary of transportation, Paula Hammond director, highways and Local programs, Kathleen Davis Stevens Pass Greenway 29 Scenic Byways coordinator, Ed Spilker Strait of Juan de Fuca - Highway 112 33 Byway leaders and an interagency advisory group with representatives from the White Pass Scenic Byway 37 Washington State Department of Transportation, Washington State Department of Agriculture, Washington State Department of Fish & Wildlife, Washington State Tourism, Washington State Parks and Recreation Commission and State Scenic BywayS Audubon Washington were also instrumental in the creation of this guide. Cape Flattery Tribal Scenic Byway 40 puBLiShing SeRviceS pRovided By deStination -
MILITARY AVIATION AUTHORITY Content
en MILITARY AVIATION AUTHORITY Content 2 — What we do _ Our mission _ Our vision _ Who we are 4 — Airworthiness 6 — Air Traffic Management (ATM) & Infrastructure 9 — Air Operation 11 — Defence Aviation Safety Management 13 — Swiss Air Force Aeromedical Institute 14 — Environment and Partnership 15 — Compliance and Quality Management 16 — Emblem Military Aviation Authority MAA Military airbase CH-1530 Payerne [email protected] www.armee.ch/maa Head of the Federal Department of Defence, Civil Protection and Sport DDPS, Federal Councillor Viola Amherd MAA, just three letters but a significant change for the Swiss military aviation. In today’s rapidly evolving world, where aviation is discover- ing a totally new range of operation with the emergence of drones and where access to airspace will soon be utmost critical, I am deeply per- suaded that the only way to achieve a maximized level of safety without prejudicing the operation in the interest of the state, is through magnifi- cation of the synergies between civil and military authorities. My prede- cessor has therefore ordered in 2017 the creation of the newborn Swiss MAA with the aim to maximize the coherence with FOCA, while high- lighting the specificities and needs of military aviation. The project team, under the lead of colonel GS Pierre de Goumoëns, was able to plan and initiate its deployment within a very short time period. I am very grate- ful to the whole team. Director of FOCA, Christian Hegner For decades, civilian aircraft and the Air Force have shared Swiss airspace. As a result, we have long had to work closely together to guarantee every- one the safe and efficient use of airspace.