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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, -
Characterization of Ecoregions of Idaho
1 0 . C o l u m b i a P l a t e a u 1 3 . C e n t r a l B a s i n a n d R a n g e Ecoregion 10 is an arid grassland and sagebrush steppe that is surrounded by moister, predominantly forested, mountainous ecoregions. It is Ecoregion 13 is internally-drained and composed of north-trending, fault-block ranges and intervening, drier basins. It is vast and includes parts underlain by thick basalt. In the east, where precipitation is greater, deep loess soils have been extensively cultivated for wheat. of Nevada, Utah, California, and Idaho. In Idaho, sagebrush grassland, saltbush–greasewood, mountain brush, and woodland occur; forests are absent unlike in the cooler, wetter, more rugged Ecoregion 19. Grazing is widespread. Cropland is less common than in Ecoregions 12 and 80. Ecoregions of Idaho The unforested hills and plateaus of the Dissected Loess Uplands ecoregion are cut by the canyons of Ecoregion 10l and are disjunct. 10f Pure grasslands dominate lower elevations. Mountain brush grows on higher, moister sites. Grazing and farming have eliminated The arid Shadscale-Dominated Saline Basins ecoregion is nearly flat, internally-drained, and has light-colored alkaline soils that are Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and America into 15 ecological regions. Level II divides the continent into 52 regions Literature Cited: much of the original plant cover. Nevertheless, Ecoregion 10f is not as suited to farming as Ecoregions 10h and 10j because it has thinner soils. -
(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. -
Tectonic Features of the Precambrian Belt Basin and Their Influence on Post-Belt Structures
... Tectonic Features of the .., Precambrian Belt Basin and Their Influence on Post-Belt Structures GEOLOGICAL SURVEY PROFESSIONAL PAPER 866 · Tectonic Features of the · Precambrian Belt Basin and Their Influence on Post-Belt Structures By JACK E. HARRISON, ALLAN B. GRIGGS, and JOHN D. WELLS GEOLOGICAL SURVEY PROFESSIONAL PAPER X66 U N IT ED STATES G 0 V ERN M EN T P R I NT I N G 0 F F I C E, \VAS H I N G T 0 N 19 7 4 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 74-600111 ) For sale by the Superintendent of Documents, U.S. GO\·ernment Printing Office 'Vashington, D.C. 20402 - Price 65 cents (paper cO\·er) Stock Number 2401-02554 CONTENTS Page Page Abstract................................................. 1 Phanerozoic events-Continued Introduction . 1 Late Mesozoic through early Tertiary-Continued Genesis and filling of the Belt basin . 1 Idaho batholith ................................. 7 Is the Belt basin an aulacogen? . 5 Boulder batholith ............................... 8 Precambrian Z events . 5 Northern Montana disturbed belt ................. 8 Phanerozoic events . 5 Tectonics along the Lewis and Clark line .............. 9 Paleozoic through early Mesozoic . 6 Late Cenozoic block faults ........................... 13 Late Mesozoic through early Tertiary . 6 Conclusions ............................................. 13 Kootenay arc and mobile belt . 6 References cited ......................................... 14 ILLUSTRATIONS Page FIGURES 1-4. Maps: 1. Principal basins of sedimentation along the U.S.-Canadian Cordillera during Precambrian Y time (1,600-800 m.y. ago) ............................................................................................... 2 2. Principal tectonic elements of the Belt basin reentrant as inferred from the sedimentation record ............ -
Brief Overview of North American Cordilleran Geology by Cin-Ty Lee Topography Map of North America
Brief overview of North American Cordilleran geology by Cin‐Ty Lee Note: make sure to take notes as I will talk or sketch on the board many things that are not presented explicitly in these slides Topography map of North America Topography map How does the NthNorth AiAmerican Cor dillera fit itinto a glbllobal contt?text? Dickinson 2004 P‐wave tomography: Seismic structure beneath western USA Burdick et al. 2008 Crustal provinces of North America (Laurentia) ‐Proterozoic and Archean terranes were already assembled by 1.6 Ga Hoffman, 1988 Crustal provinces in southwestern USA Hoffman, 1988 Bennett and DePaolo, 1987 Some examples of tectonic margins for your reference Dickinson and Snyder, 1978 1.1 Ga = Rodinia Super‐continent (Grenvillian age) Neo‐Proterozoic = Rodinia breaks up “western” margin of Laurentia represents a passive margin due to opening of the Panthalassan ocean 700‐400 Ma Western margin of Laurentia represents a passive margin Dickinson and Snyder, 1978 400‐250 Ma Passive margin is interrupted in Devonian times by the accretion of island arcs Antler and Sonoma orogenies Accretion of allochthonous terranes to the western margin of the NhNorth AiAmerican craton Antler/Sonoma orogenies result in the accretion of Paleozoic island arc terranes to western North America Permian Formation of Pangea “”“western” margin of NhNorth AiAmerica now didominate d by subduct ion zone 250‐50 Ma Subduction results in continued accretion of fringing island arcs and the generation of continental magmatic arcs Sierra Nevada batholith Sevier and -
Hydrodynamic Mechanism for the Laramide Orogeny
Hydrodynamic mechanism for the Laramide orogeny Craig H. Jones1, G. Lang Farmer1, Brad Sageman2, and Shijie Zhong3 1Department of Geological Sciences and CIRES (Cooperative Institute for Research in Environmental Science), University of Colo- rado at Boulder, 2200 Colorado Avenue, Boulder, Colorado 80309-0390, USA 2Department of Earth and Planetary Sciences, Northwestern University, 1850 Campus Drive, Evanston, Illinois 60208-2150, USA 3Department of Physics, University of Colorado at Boulder, 2000 Colorado Avenue, Boulder, Colorado 80309-0390, USA ABSTRACT INTRODUCTION subduction and attendant subduction erosion only affected only a narrow (~200 km) swath The widespread presumption that the Far- The Late Cretaceous to early Tertiary of oceanic lithosphere underthrusting present- allon plate subducted along the base of North Laramide orogeny that affected much of south- day southern California (Barth and Schneider- American lithosphere under most of the western North America was not only a major man, 1996; Saleeby, 2003). If so, why was the western United States and ~1000 km inboard mountain building event, but also coincided with shallowly subducting lithosphere so restricted from the trench has dominated tectonic stud- major shifts in the distribution of both igneous spatially, and how could such narrow “fl at-slab” ies of this region, but a number of variations activity and sedimentary depocenters. Despite produce the array of geologic features generally of this concept exist due to differences in the critical role the Laramide orogeny played in attributed to the Laramide orogeny throughout interpretation of some aspects of this orogeny. the geologic evolution of western North Amer- western North America? We contend that fi ve main characteristics are ica, its origin remains enigmatic (e.g., English To address these issues we explore in this central to the Laramide orogeny and must and Johnston, 2004). -
The Geological Framework of the Yukon Territory by C
Y GSEOLOGICAL URVEY The Geological Framework of the Yukon Territory by C. Hart The Yukon Territory occupies the northern portion of a large geologic (and physiographic) province known as the Cordillera. This province is composed of relatively young mountain belts that range from Alaska to Mexico. Like most of the Cordillera, Yukon is composed of a diverse array of rock types that record more than a billion years of geological history. Most of the rocks have been affected by folding, faulting, metamorphism and uplift during various deformation events over at least the last 190 million years. This deformation has resulted in a complex arrangement of rock units and the mountainous terrain we see today. In Yukon, there are two main geological components which are largely separated by a major, northwest- trending fault (the Tintina): 1) the northeastern region is composed of a thick, older sequence of sedimentary rocks which was deposited upon a stable geological basement; and 2) the southwestern region is composed of a younger, complex mosaic of varying rock types that amalgamated and accreted to the stable sedimentary package. This paper briefly describes the geological framework of Yukon south of 65 degrees N and, with some exceptions, uses the Tectonic Assemblage Map of the Canadian Cordillera (Wheeler and McFeely 1991) and the Terrane Map of the Canadian Cordillera (Wheeler et al. 1991) as a foundation. However, some of the names used on these maps have been superseded by new terminology and they are included in this paper. Recent brief syntheses of Yukon physiography and geology are rare (Tempelman-Kluit, 1979; 1981), although geological compilations of Cordilleran geology are numerous and contain useful information about Yukon geology (Monger et al., 1982; Monger, 1989; Gabrielse and Yorath, 1992). -
108Th Congress of the United States WASHINGTON CANADA
108th Congress of the United States WASHINGTON CANADA 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 33 3 3 3 333333 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 Osoyoos Nooksack 3 3 3 3 3 3 3 Lake Trust Land 3 3 3 3 3 3 3 3 3 3 3 r 3 e 3 3 v 3 3 i 3 R 3 Birch 3 ck 3 Ross Strait of Georgia 3 sa 3 3 Bay ok 3 o 3 N 3 3 Nooksack 3 Lake 3 3 3 3 Trust Land 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 North Cascades 3 3 3 3 3 3 3 3 3 3 3 National Park 3 WHATCOM 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 PEND 3 3 3 3 3 3 3 3 3 3 3 3 3 Lummi Nooksack Res 3 3 3 3 3 3 3 3 Res 3 3 3 OREILLE 3 3 3 3 3 3 3 Bellingham 3 3 3 Bay 3 33 3 3 Pend Oreille River 3 3 3 3 3 3 3 3 3 3 3 Bellingham 3 3 3 3 3 3 3 3 3 3 3 3 3 Ross Lake 3 3 Cowlitz 3 3 3 3 3 3 3 3 3 3 3 3 3 NRA 3 3 3 3 3 3 3 3 3 3 3 3 Bay 3 3 3 3 3 3 3 Okanogan River 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 Samish 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 TDSA 3 3 3 3 3 3 3 3 3 3 3 Samish 3 3 3 3 3 3 3 3 Rosario Strait Bay 3 3 FERRY 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 Upper Skagit Res 3 SAN JUAN 3 Haro Strait 3 North Cascades 3 3 3 3 3 3 3 National Park 3 OKANOGAN Upper Skagit Res 3 3 3 3 3 3 3 3 3 Skagit River 3 3 3 3 3 3 3 Padilla 3 3 3 3 Griffin Bay 3 3 3 3 3 3 3 Bay 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 US Coast Guard Station 3 3 3 SKAGIT 3 3 3 3 3 3 3 Neah Bay 3 3 3 3 3 3 3 3 3 3 3 STEVENS 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 -
The Skagit-High Ross Controversy: Negotiation and Settlement
Volume 26 Issue 2 U.S. - Canada Transboundary Resource Issues Spring 1986 The Skagit-High Ross Controversy: Negotiation and Settlement Jackie Krolopp Kirn Marion E. Marts Recommended Citation Jackie K. Kirn & Marion E. Marts, The Skagit-High Ross Controversy: Negotiation and Settlement, 26 Nat. Resources J. 261 (1986). Available at: https://digitalrepository.unm.edu/nrj/vol26/iss2/6 This Article is brought to you for free and open access by the Law Journals at UNM Digital Repository. It has been accepted for inclusion in Natural Resources Journal by an authorized editor of UNM Digital Repository. For more information, please contact [email protected], [email protected], [email protected]. JACKIE KROLOPP KIRN* and MARION E. MARTS** The Skagit-High Ross Controversy: Negotiation and Settlement SETTING AND BACKGROUND The Skagit River is a short but powerful stream which rises in the mountains of southwestern British Columbia, cuts through the northern Cascades in a spectacular and once-remote mountain gorge, and empties into Puget Sound approximately sixty miles north of Seattle. The beautiful mountain scenery of the heavily glaciated north Cascades was formally recognized in the United States by the creation of the North Cascades National Park and the Ross Lake National Recreation Area in 1968, and earlier in British Columbia by creation of the E.C. Manning Provincial Park. The Ross Lake Recreation Area covers the narrow valley of the upper Skagit River in Washington and portions of several tributary valleys. It was created as a political and, to environmentalists who wanted national park status for the entire area, controversial, compromise which accom- modated the city of Seattle's Skagit River Project and the then-planned North Cascades Highway. -
OPPOSITE THRUST-VERGENCIES in the PRECORDILLERA and WESTERN CORDILLERA in NORTHERN CHILE and Structurally LINKED CENOZOIC PALEOENVIRONMENTAL EVOLUTION
Fourth /SAG. Goettingen (Germany), 04 - 06//0//999 155 OPPOSITE THRUST-VERGENCIES IN THE PRECORDILLERA AND WESTERN CORDILLERA IN NORTHERN CHILE AND STRUCTURALLy LINKED CENOZOIC PALEOENVIRONMENTAL EVOLUTION Reynaldo CHARRIER(I-7), Gérard HERAIL(2-7), John FLYNN(3), Rodrigo RIQUELME(I-7), Marcelo GARCIA(4-7), Darin CROFf(5) and André WYSS(6) (1) Departamento de Geologfa, Universidad de Chile; [email protected]. (2) IRD, 209-213, Rue La Fayette, 75010 Paris,[email protected]. (3) The Field Museum of Natural History, Chicago, USA. [email protected]. (4) SERNAGEOMIN. Av. Sta. Maria 0104, Providencia, Santiago, Chile. [email protected]. (5) The Field Museum of Natural History, Chicago, and University of Chicago, USA. (6) Department of Geological Sciences, University of California Santa Barbara, USA [email protected]. (7) Convenio IRD-Departamento de Geologïa, Universidad de Chi le. KEY WORDS: Altiplano, Chile, syntectonic sedimentation, Cenozoic paleoenvironment. INTRODUCTION Morphologie units in the northern Chilean Andes parailei one another and the offshore trench. These units are, from west to east: Coastal Cordillera, Central Depression, Precordillera, Western Cordillera and Altiplano (Fig. i). The development of the west part of the Western Cordillera (Chapiquifia-Belén Ridge), in the Chilean Altiplano, was controlled by two diverging, trench-parallel systems of thrusts and folds, one located along the Precordil1era and the other along the eastern side of the Western Cordillera. Although total shortening associated with these systems is only 12 to 14 km, their activity determined the development of fluvial and lacustrine basins which recorded the synorogenic paleoenvironmental evolution of this region. We describe here facies, geometry and chronology of the deposits associated with both systems and provide an explanation for the differing depositional environments developed on the Precordillera and the Western Cordillera. -
40Ar/39Ar Mineral Dates from Retrogressed Eclogites Within the Baltoscandian Miogeocline: Implications for a Polyphase Caledonian Orogenic Evolution
40Ar/39Ar mineral dates from retrogressed eclogites within the Baltoscandian miogeocline: Implications for a polyphase Caledonian orogenic evolution R. D. DALLMEYER Department of Geology, University of Georgia, Athens, Georgia 30602 D. G. GEE Geological Survey of Sweden, Box 670, S-751 28 Uppsala, Sweden ABSTRACT Late Silurian to Early Devonian transport suggest that this tectonic activity occurred while onto the Baltoscandian Platform. Baltica and Laurentia were separated by a con- Late Proterozcic, rift-fades dolerite dikes siderable expanse of the Iapetus Ocean (Ilruton within Baltoscandian rocks of the Seve INTRODUCTION and Bockelie, 1980). Nappe Complex locally underwent eclogite A comprehensive geochronological program metamorphism during Caledonian orogen- Scandinavian portions of the Caledonian oro- is underway to more fully document the ;xtent esis. Hornblende from retrograde amphibo- gen are represented by a succession of far- and character of the pre-Scandian tectono- lite selvages developed around two eclogite traveled allochthons which were emplaced onto thermal record within the Scandinavian Cal- boudins exposed at Grapesvare, Norrbotten the Baltoscandian Platform during the early to edonides. This report presents new 40Ar/39Ar County, Sweden, record identical 40Ar/39Ar middle Paleozoic (Fig. 1). Medium- and high- data for hornblende in retrograde selvages plateau dates of 491 ± 8 Ma. Phengitic mus- grade Baltoscandian rocks of the Seve Nappe developed from eclogite assemblages within covite from host schists records plateau dates Complex constitute one of the major tectonic Seve rocks. These results bear directly ori both of 447 ± 7 Ma and 436 ± 7 Ma. Coexisting units in central parts of the orogen (Zachrisson, the chronology and nature of pre-Scandian oro- biotite yields plateau dates of 594 ± 10 Ma 1973).