DOCSLIB.ORG

Zircon Geochemistry and Geochronology of the Seven Devils

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Zircon Geochemistry and Geochronology of the Seven Devils ZIRCON GEOCHEMISTRY AND GEOCHRONOLOGY OF THE SEVEN DEVILS MOUNTAINS, WESTERN IDAHO: TESTING PROPOSED TIES TO THE WRANGELLIA TERRANE A THESIS SUBMITTED TO THE GRADUATE SCHOOL IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE MASTER OF SCIENCE BY HEATHER CASARES DR. KIRSTEN NICHOLSON- ADVISOR DEPARTMENT OF GEOLOGICAL SCIENCES BALL STATE UNIVERSITY MUNCIE INDIANA MAY 2019 Table of Contents Chapter 1 Overview……………………………………………………………………………….1 Introduction………………………………………………………………………………..1 Previous Work…………………………………………………………………………….3 Objectives and Significance……………………………………………………………….4 Chapter 2 Background…………………………………………………………………………….6 Tectonics of Western North America……………………………………………………..6 Geologic Setting………………………………………………………………………..….9 The Blue Mountains Province…………………………………………………………….9 Wallowa terrane Seven Devils Group…………………………………………………..10 Baker terrane………………………………………………………………………….…13 Izee terrane………………………………………………………………………….…..13 Olds Ferry terrane……………………………………………………………………….13 Wrangellia…………………………………………………………………………….….14 Chapter 3 Analytical Methods…………………………………………………………..……….17 Sample Collection………………………………………….…………………………….17 Thin Section Preparation…………………………………………………………………19 Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) Analysis…………………………………………………………………………………..19 X-ray Fluorescence spectrometry (XRF) Analysis…………………………………..…..21 Chapter 4 Manuscript………………………………………………………………………….....24 Acknowledgements………………………………………………………………………………49 References………………………………………………………………………………………..50 Appendix……………………………………………………………………………………...….59 i List of Tables Table A-1: U-Pb dating and of zircons from this study using LA-ICPMS…………………..…68 Table A-2: In Situ Lu-Hf isotopic data of zircons from this study…………………………..…..72 Table A-3: Average εHf(t) and errors for the Seven Devils samples……………...…………….73 Table A-4: Loss on Ignition (LOI)…………………………………………………………….....73 Table A-5: Whole Rock Geochemistry for the Seven Devils terrane determined by XRF……..74 ii List of Figures Figure 1-1: Location of the Seven Devils Mountains in Western Idaho………………………….1 Figure 2-1: Arc-arc collision model of the Blue Mountains Province……………………………8 Figure 2-2: The Blue Mountains Province and locations of terranes……………………………10 Figure 2-3: Close up view of the Wallowa terrane and rocks…………………………………..11 Figure 2-4: The location of the Wrangellia terrane……………………………………………..16 Figure 3-1: Sample location map…………………………………………………………...……18 Figure A-1: Sample SD001………………………………………………………………………60 Figure A-2: Sample SD002………………………………………………………………………61 Figure A-3: Sample SD003………………………………………………………………………62 Figure A-4: Sample SD004………………………………………………………………………63 Figure A-5: Sample SD005………………………………………………………………………64 Figure A-6: Sample SD006………………………………………………………………………65 Figure A-7: Sample SD007………………………………………………………………………66 Figure A-8: Sample SD008………………………………………………………...…………….67 Figure A-9: Sample SD009………………………………………………………………………68 Figure A-10: Average U-Pb ages for sample SD004…………………………………………….70 Figure A-11: Average U-Pb ages for sample SD006…………………………………………….70 Figure A-12: Average U-Pb ages for sample SD007…………………………………………….71 Figure A-13: Average U-Pb ages for sample SD008………………………………………….…71 Figure A-14: Average U-Pb ages for sample SD009…………………………………………….72 Figure A-15: Volcanic Rock Diagram Using Immobile Trace Elements………………………..76 Figure A-16: Discriminate within-plate granites, volcanic arc granites & ocean ridge granites using Nb vs. Y…………………………………………………………………………...………76 iii Figure A-17: Discriminate within-plate granites, volcanic arc granites & ocean ridge granites using Rb vs. Nb+Y……………………………………………………………………………….77 iv Chapter One 1.1 Introduction The western part of North America preserves a rich tectonic history. The western margin of the North American Craton has many terrains and microcontinents that have accreted to it. The boundary between terranes is known as the suture zone. These terranes and microcontinents began forming during and after the breakup of Pangaea in the early Triassic (Murphy et al., 2009). The forces created by such massive movement allowed for changes in the plate boundaries which caused the Farallon plate to begin subducting off of North America (Sigloch and Mihalynuk, 2013). The process of subduction ultimately created much of the volcanic arc terranes and microcontinents that now form the North American Cordillera. Figure (1-1) Location map of the Seven Devils Mountains field study area from (Farag, 2018). 1 The Seven Devils Mountains (Figure 1-1) are located along a 70 km stretch on the eastern side of the Snake River in Western Idaho within an area known as Hells Canyon Wilderness by the town of Riggings, Idaho (Sarewitz, 1983). The Seven Devils Mountains consist of mostly intermediate to mafic igneous rocks with rare felsic rocks that have all been variably metamorphosed. These rocks are considered to be the easternmost exposure of Permian to Triassic volcanic rocks in the North American Cordillera (Vallier, 1977). Modern analytical tools and scientific understanding of trace element chemistry has improved significantly since the last study of the Seven Devils Mountains, conducted in the 1970s to the 1980s (Jones et al., 1977; Sarewitz, 1982). Conducting modern whole rock geochemical analysis including major and trace element geochemistry, and zircon U-Pb geochronology, will bring new insight on the formation of the Seven Devils, how volcanic arcs evolve over time, and importantly, how western North America has evolved. The North American Cordillera provides an excellent location to study terrane translation in an accretionary orogeny. Previous studies and speculations have provided the Baja B.C. (Baja-British Columbia) hypothesis of terrane transport (Champion et al., 1984; Umhoefer, 1987; Wyld and Wright, 2001; Wyld et al., 2006). Northward terrane transport in the Cordillera, such as the Wrangellia terrane, is supported by fault displacements and paleomagnetic data suggesting displacements from 1100 to 3000 km in Washington and the British Columbia (Champion et al., 1984; Wynne et al., 1995; Wyld et al., 2006). Trace element geochemistry, improved U-Pb geochronology, and Hf isotope analysis will allow a better understanding of the tectonic history of the terrane and test models for northward displacement of the arc, by allowing for robust comparisons with data from the Wrangellia terrane and the surrounding Blue Mountains terranes. If the Seven Devils terrane is indeed part 2 of the Wrangellia terrane, then collected data will provide additional evidence for significant long-range transport along the Cordilleran margin. If not, then the Seven Devils terrane may represent an independent tectonic element of the Cordillera that may not require orogenic displacement. 1.2 Previous Work The main terranes (Wallowa, Baker, Izee, and Olds Ferry) of the Blue Mountains Province formed as island arc systems along the continental margin of western Laurentia. The Wallowa terrane has been known by many names such as the “volcanic arc terrane”, “Wallowa Mountains–Seven Devils Mountains volcanic arc terrane” (Brooks and Vallier, 1978), and the “Seven Devils terrane” (Vallier, 1977). The Wallowa terrane is the most outboard from the continental margin and is an island arc terrane that formed in an intra- oceanic setting in the Blue Mountains Province (LaMaskin et al., 2008; 2011). The Seven Devils terrane, which has been interpreted to be part of the Wallowa terrane, and even the Wrangellia terrane, is a volcanic complex in what is now western Idaho. Vallier (1977) described the Seven Devils and identified four separate formations: The Permian Windy Ridge formation, Permian Hunsaker Creek formation, Triassic Wild Sheep Creek formation, and the Triassic Doyle Creek formation. The majority of the volcanic rocks in these formations were called spilite, keratophyre, and quartz keratophyre. They are now reclassified as metabasalt, meta-andesite, metadacite, and metarhyolite based on their greenschist metamorphic facies (Vallier et al. 2016). Previous work comparing the Seven Devils to Wrangellia includes paleomagnetic studies, comparative studies using fossils, and geochemistry. Several authors including Hillhouse et al. (1982) and Harbert et al. (1995) worked to provide evidence for the migration of the Wallowa and Wrangellia terranes using 3 paleomagnetism. The core samples collected for these studies include volcanoclastic sedimentary, sedimentary, and volcanic flow rocks. Paleomagnetic data provide inclination and declination information that yields a paleolatitude, as well as paleopole locations comparable to other data sets. The two studies from Hillhouse in 1982 and again in 1984 on the Wallowa and Wrangellia terranes respectively, provide a paleolatitude ranging from 10 to 18 degrees from the Late Triassic in either the northern or southern hemisphere. The studies also show that there had to have been some kind of rotation in the Seven Devils terrane in order to bring it to where it is present day (Hillhouse, 1984). Comparative fossil studies and the use of fossils were the main source for age dating the surrounding rocks. The Seven Devils terrane contains fossils in the Wild Sheep Creek formation. These fossils are concentrations of the bivalves Daonella degeeri and D. frami (Jones, 1977). These fossils resemble others in beds beneath the Nikolai Greenstone of the Wrangellia terrane in southern Alaska. The only other congeneric bivalves that resemble these two species are seen in only two other localities
Load more

Recommended publications
  • The Natural Science Underlying Big History
    Review Article [Accepted for publication: The Scientific World Journal, v2014, 41 pages, article ID 384912; printed in June 2014 http://dx.doi.org/10.1155/2014/384912] The Natural Science Underlying Big History Eric J. Chaisson Harvard-Smithsonian Center for Astrophysics Harvard University, Cambridge, Massachusetts 02138 USA [email protected] Abstract Nature’s many varied complex systems—including galaxies, stars, planets, life, and society—are islands of order within the increasingly disordered Universe. All organized systems are subject to physical, biological or cultural evolution, which together comprise the grander interdisciplinary subject of cosmic evolution. A wealth of observational data supports the hypothesis that increasingly complex systems evolve unceasingly, uncaringly, and unpredictably from big bang to humankind. This is global history greatly extended, big history with a scientific basis, and natural history broadly portrayed across ~14 billion years of time. Human beings and our cultural inventions are not special, unique, or apart from Nature; rather, we are an integral part of a universal evolutionary process connecting all such complex systems throughout space and time. Such evolution writ large has significant potential to unify the natural sciences into a holistic understanding of who we are and whence we came. No new science (beyond frontier, non-equilibrium thermodynamics) is needed to describe cosmic evolution’s major milestones at a deep and empirical level. Quantitative models and experimental tests imply that a remarkable simplicity underlies the emergence and growth of complexity for a wide spectrum of known and diverse systems. Energy is a principal facilitator of the rising complexity of ordered systems within the expanding Universe; energy flows are as central to life and society as they are to stars and galaxies.
    [Show full text]
  • Subduction Polarity in Ancient Arcs: a Call to Integrate Geology And
    COMMENT & REPLY Subduction Polarity in Ancient Arcs: A Call to Integrate Geology and Geophysics to Decipher the Mesozoic Tectonic History of the Northern Cordillera of North America: REPLY Terry L. Pavlis, Dept. of Geological Sciences, University of Texas, El Paso, Texas 79968, USA; Jeffrey M. Amato, Dept. of Geological Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA; Jeffrey M. Trop, Dept. of Geology and Environmental Geosciences, Bucknell University, Lewisburg, Pennsylvania 17837, USA; Kenneth D. Ridgway, Dept. of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907, USA; Sarah M. Roeske, Earth and Planetary Sciences Dept., University of California, Davis, California 95616, USA; and George E. Gehrels, Dept. of Geosciences, University of Arizona, Tucson, Arizona, 85721, USA INTRODUCTION drafts of the paper. However, when we problem is not solved, which underscores We welcome the opportunity to discuss the realized that experts in this field were our conclusion that resolving ancient sub- views expressed by Sigloch and Mihalynuk in actively debating the topic, we reduced our duction polarity problems requires a con- their Comment (Sigloch and Mihalynuk, discussion to a short paragraph. In their certed collaborative effort between the geo- 2020; referred to here as SM) on Pavlis et al. Comment, SM reiterate parts of their model logic and geophysical communities. (2019) because it provides an opportunity to but emphasize a consensus in the geophysi- A foundation of Sigloch and Mihalynuk’s elaborate on the criteria for determining sub- cal community that deep mantle tomo- (2013, 2017) interpretations is that plate duction polarity, an important problem in the graphic anomalies are subduction zone rem- reconstructions restore North America to a North American Cordillera and for tectonic nants.
    [Show full text]
  • 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.
    [Show full text]
  • Confronting History on Campus
    CHRONICLEFocusFocus THE CHRONICLE OF HIGHER EDUCATION Confronting History on Campus As a Chronicle of Higher Education individual subscriber, you receive premium, unrestricted access to the entire Chronicle Focus collection. Curated by our newsroom, these booklets compile the most popular and relevant higher-education news to provide you with in-depth looks at topics affecting campuses today. The Chronicle Focus collection explores student alcohol abuse, racial tension on campuses, and other emerging trends that have a significant impact on higher education. ©2016 by The Chronicle of Higher Education Inc. All rights reserved. No part of this publication may be reproduced, forwarded (even for internal use), hosted online, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the publisher, except in the case of brief quotations embodied in critical reviews and certain other noncommercial uses permitted by copyright law. For bulk orders or special requests, contact The Chronicle at [email protected] ©2016 THE CHRONICLE OF HIGHER EDUCATION INC. TABLE OF CONTENTS OODROW WILSON at Princeton, John Calhoun at Yale, Jefferson Davis at the University of Texas at Austin: Students, campus officials, and historians are all asking the question, What’sW in a name? And what is a university’s responsibil- ity when the name on a statue, building, or program on campus is a painful reminder of harm to a specific racial group? Universities have been grappling anew with those questions, and trying different approaches to resolve them. Colleges Struggle Over Context for Confederate Symbols 4 The University of Mississippi adds a plaque to a soldier’s statue to explain its place there.
    [Show full text]
  • New Late Carboniferous Heritschioidinae (Rugosa) from the Kuiu Island Area and Brooks Range, Alaska
    Geologica Acta, Vol.12, Nº 1, March 2014, 29-52 DOI: 10.1344/105.000002074 New Late Carboniferous Heritschioidinae (Rugosa) from the Kuiu Island area and Brooks Range, Alaska J. FEDOROWSKI1 C.H. STEVENS2 E. KATVALA3 1Institute of Geology, Adam Mickiewicz University Makow Polnych 16, PL-61-606, Poznan, Poland. E-mail: [email protected] 2Department of Geology, San Jose Unversity San Jose, California 95192, USA. E-mail: [email protected] 3Department of Geology, University of Calgary Calgary, Canada. E-mail: [email protected] ABS TRACT Three new species of the genus Heritschioides, i.e., H. alaskensis sp. nov., H. kuiuensis sp. nov., and H. splendidus sp. nov., and Kekuphyllum sandoense gen. et sp. nov. from the northeastern Kuiu Island area and nearby islets, part of Alexander terrane in southeastern Alaska, and Heritschioides separatus sp. nov. from the Brooks Range, Alaska, are described and illustrated. The three new fasciculate colonial coral species from the Kuiu Island area, collected from the Moscovian Saginaw Bay Formation, are phylogenetically related to those of probable Bashkirian age in the Brooks Range in northern Alaska as shown by the presence of morphologically similar species of Heritschioides. These corals from both areas also are related to one species in the Quesnel terrane in western Canada. Kekuphyllum sandoense from the Saginaw Bay Formation of the Kuiu Island area is the only cerioid-aphroid species within the Subfamily Heritschioidinae described so far. The complete early ontogeny of a protocorallite is for the first time described here on a basis of H. kuiuensis sp. nov. and compared to the hystero-ontogeny in order to show similarities and differences in those processes.
    [Show full text]
  • Wolverines in Idaho 2014–2019
    Management Plan for the Conservation of Wolverines in Idaho 2014–2019 Prepared by IDAHO DEPARTMENT OF FISH AND GAME July 2014 2 Idaho Department of Fish & Game Recommended Citation: Idaho Department of Fish and Game. 2014. Management plan for the conservation of wolverines in Idaho. Idaho Department of Fish and Game, Boise, USA. Idaho Department of Fish and Game – Wolverine Planning Team: Becky Abel – Regional Wildlife Diversity Biologist, Southeast Region Bryan Aber – Regional Wildlife Biologist, Upper Snake Region Scott Bergen PhD – Senior Wildlife Research Biologist, Statewide, Pocatello William Bosworth – Regional Wildlife Biologist, Southwest Region Rob Cavallaro – Regional Wildlife Diversity Biologist, Upper Snake Region Rita D Dixon PhD – State Wildlife Action Plan Coordinator, Headquarters Diane Evans Mack – Regional Wildlife Diversity Biologist, McCall Subregion Sonya J Knetter – Wildlife Diversity Program GIS Analyst, Headquarters Zach Lockyer – Regional Wildlife Biologist, Southeast Region Michael Lucid – Regional Wildlife Diversity Biologist, Panhandle Region Joel Sauder PhD – Regional Wildlife Diversity Biologist, Clearwater Region Ben Studer – Web and Digital Communications Lead, Headquarters Leona K Svancara PhD – Spatial Ecology Program Lead, Headquarters Beth Waterbury – Team Leader & Regional Wildlife Diversity Biologist, Salmon Region Craig White PhD – Regional Wildlife Manager, Southwest Region Ross Winton – Regional Wildlife Diversity Biologist, Magic Valley Region Additional copies: Additional copies can be downloaded from the Idaho Department of Fish and Game website at fishandgame.idaho.gov/wolverine-conservation-plan Front Cover Photo: Composite photo: Wolverine photo by AYImages; background photo of the Beaverhead Mountains, Lemhi County, Idaho by Rob Spence, Greater Yellowstone Wolverine Program, Wildlife conservation Society. Back Cover Photo: Release of Wolverine F4, a study animal from the Central Idaho Winter Recreation/Wolverine Project, from a live trap north of McCall, 2011.
    [Show full text]
  • Selections from the Correspondence of The
    .. SELECTIONS FROM THE CORRESPONDENCE OF THE FIRST LORD ACTON ~ 1 'I A FRIEND sends me La l·'lanare LibCrale of Ghent for August 21st, with this article marked in heavy blue pencil. I publish it without any comment whatever. ," "CATHOLIC TOLERANCE /~ / }' :?£, "The punishment of death for heretics. ' "Fr. Lcpicia, professor of theology at the College of Prop- . aganda in Rome, is the author of a text-book in common use by the future priests who study at Rome. The book is entitled: Ooncerning the Stability ana the Proorese 01 Dogma. It was reissued with augmentations in 1910. A new edition has just appeared, bearing the approbation of high Church authorities. And here is what one reads on page 103: "'Q. Can heretics be tolerated, and if so, on what condi- tions?' "'A. As soon as one proclaims in public a heretical doc- trine, and tries to corrupt others by words or example, he can not only be excommunicated (to speak abstractly) but he ought to be killed, in all justice, to the end that he may not corrupt I a very great number by contamination. For a bad man is worse than a wild beast, and he docs more harm, as Aristotle says t (Ethic8 I, vil, in fine). So as it is not evil to kill a noxious beast of the forest, it is good to take away the life of a heretic who denies divine truth and hinders the salvation of others.' "And on page 200 this sentence is to be found: "'To the Church returns, in truth, the right of pronouncing sentence of death against heretics.' Who then can say that the Roman Catholic Church is becoming more tolerant? Nunc erudimini/" '00.-- __ > _ i, ~-....
    [Show full text]
  • Wrangellia Flood Basalts in Alaska, Yukon, and British Columbia: Exploring the Growth and Magmatic History of a Late Triassic Oceanic Plateau
    WRANGELLIA FLOOD BASALTS IN ALASKA, YUKON, AND BRITISH COLUMBIA: EXPLORING THE GROWTH AND MAGMATIC HISTORY OF A LATE TRIASSIC OCEANIC PLATEAU By ANDREW R. GREENE A THESIS SUBMITTED iN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES (Geological Sciences) UNIVERSITY OF BRITISH COLUMBIA (Vancouver) August 2008 ©Andrew R. Greene, 2008 ABSTRACT The Wrangellia flood basalts are parts of an oceanic plateau that formed in the eastern Panthalassic Ocean (ca. 230-225 Ma). The volcanic stratigraphy presently extends >2300 km in British Columbia, Yukon, and Alaska. The field relationships, age, and geochemistry have been examined to provide constraints on the construction of oceanic plateaus, duration of volcanism, source of magmas, and the conditions of melting and magmatic evolution for the volcanic stratigraphy. Wrangellia basalts on Vancouver Island (Karmutsen Formation) form an emergent sequence consisting of basal sills, submarine flows (>3 km), pillow breccia and hyaloclastite (<1 1cm), and subaerial flows (>1.5 km). Karmutsen stratigraphy overlies Devonian to Permian volcanic arc (—‘380-355 Ma) and sedimentary sequences and is overlain by Late Triassic limestone. The Karmutsen basalts are predominantly homogeneous tholeiitic basalt (6-8 wt% MgO); however, the submarine part of the stratigraphy, on northern Vancouver Island, contains picritic pillow basalts (9-20 wt% MgO). Both lava groups have overlapping initial and ENd, indicating a common, ocean island basalt (OIB)-type Pacific mantle source similar to the source of basalts from the Ontong Java and Caribbean Plateaus. The major-element chemistry of picrites indicates extensive melting (23 -27%) of anomalously hot mantle (‘—1500°C), which is consistent with an origin from a mantle plume head.
    [Show full text]
  • Michael Warren Powellis
    WELCOME to the Fifteenth Annual Last Frontier Theatre Conference. We at Prince William Sound Community College are very proud of this event, and hopefully by the end of the week you will see why. I started coming to Valdez (for the Conference) in 1995, its third year, and it became an annual pilgrimage for me. I quit jobs to make it here. I ran up credit cards. I did whatever it took for me to get to spend the week here. I crashed on the floor at the college, survived off the food at receptions, and worked on whatever anyone asked me to. No one was more important to me in those early years than Michael Warren Powell, the first coordinator of the Play Lab. I remember being in awe of how insightful the responding panel was critiquing plays that were all (in my opinion) pretty problematic. Michael and the other panelists became my idols. Which made it all the more important to me when one day I was hanging out with friends at the picnic tables in the middle of the park strip and we saw Michael walking our direction. He came up and engaged us in conversation, and we became friends. He let us know that he considered us his peers. In the late 90s, I decided that, of all the people I had met, there was no one whose life I wanted to emulate more than Michael’s. I made producing new work and nurturing playwrights my focus, and the answer to most of my questions can be found in the answer to the question “What would Michael do?” I am very excited to have him back with us this year.
    [Show full text]
  • The Nesting Season June 1 - July 31, 1976
    The Nesting Season June 1 - July 31, 1976 NORTHEASTERN MARITIME REGION SoA. /Davis W. Finch SeventeenNorth American reportstotaling 23 individuals of Black-browed and Yellow-nosed Mostof New Englandexperienced a hot, dry June-- it Albatrossprior to 1973have been carefullysum- was in fact the hottest and driest June in Massachusetts marized by McDaniel (Am. Birds 27:563-565), history.July was cooler and wetter,but theseconditions oneother convincing Gulf of Maine report(1968) seemedto have no detectableeffect on breedingbirds. being known to this editor. Sevensubsequent Writing of New Hampshire,Vera Hebert characterized reports appearingin Am. Birds involvedeight the periodquite succinctly: "Never has a nestingseason albatrossessighted from Maryland to Nova Sco- beenmore normal". Eventhe severalfirst statebreeding tia: five Black-broweds,two probable Black- recordsin NewEngland came only as gentle surprises. browedsand one positiveYellow-nosed, to which can be added this summer's Massachusetts birds. It mightbe notedthat of this overalltotal of 34 e. North American albatrosses (18, or more than half of them, in the Northeastern Maritime Region), 19 were identified as, and in five instancesproven to be, Yellow-nosed;that while Black-browedis the vagrant albatrossof the e. North Atlantic, North America'sonly provenone is still the 1935Greenland specimen; that aside fromthat bi•d all Black-broweds(11 plustwo "probables")have been reported since 1972; that consideringthe subtletiesof albatrossdiscrimina- tion curiouslyfew, in fact only two havenot been "identified" (see Warham, Bourne and Elliott, Albatross Identification in the North Atlantic-- Am. Birds28:585-603), and that consequentlyan unambiguousBIack-browed photograph would do wondersfor the persistentmalaise many feel regardingreports of this species. Happily, for the first time in over a year recordscam, OTHER TUBENOSES-- Followinga patternmore or fromalmost all partsof the Region,though in somecases less apparent in recent years, the withdrawal of N.
    [Show full text]
  • Upper-Crustal Cooling of the Wrangellia Composite Terrane in the Northern St. Elias Mountains, Western Canada
    RESEARCH Upper-crustal cooling of the Wrangellia composite terrane in the northern St. Elias Mountains, western Canada Sarah Falkowski1 and Eva Enkelmann2 1UNIVERSITY OF TÜBINGEN, DEPARTMENT OF GEOSCIENCES, 72074 TÜBINGEN, GERMANY 2UNIVERSITY OF CINCINNATI, DEPARTMENT OF GEOLOGY, CINCINNATI, OHIO 45221-0037, USA ABSTRACT This study presents the long-term exhumation history of the Wrangellia composite terrane of the remote and ice-covered northern St. Elias Mountains in southwest Yukon, northwest British Columbia, and adjacent Alaska. Detrital zircon and apatite fission-track age distributions are presented from 21 glacial catchments. The detrital sampling approach allows for a large spatial coverage (~30,000 km2) and access to material eroded beneath the ice. An additional five bedrock samples were dated by zircon fission-track analysis for a comparison with detrital results. Our new thermochronology data record the Late Jurassic–mid-Cretaceous accretion of the Wrangellia composite terrane to the former North American margin and magmatism, which reset the older thermal record. The good preservation of the Jurassic–Cretaceous record suggests that Cenozoic erosion must have been limited overall. Nonetheless, Eocene spreading-ridge subduction and Oligocene–Neogene cooling in response to the ongoing Yakutat flat-slab subduction are evident in the study area despite its inboard position from the active plate boundary. The results further indicate an area of rapid exhumation at the northern end of the Fairweather fault ca. 10–5 Ma; this area is bounded by discrete, unmapped structures. The area of rapid exhumation shifted southwest toward the plate boundary and the center of the St. Elias syntaxis after 5 Ma. Integrating the new data with published detrital thermochronology from the southern St.
    [Show full text]
  • Clearwater Rapid Watershed Assessment
    Clearwater - 17060306 Idaho 8 Digit Hydrologic Unit Profile December 2006 Tensed Farmington Clearwater - 17060306 8-Digit Hydrologic Unit LATAHLATAH Location Map Potlatch Bovill WHITMAN WHITMAN Deary (Washington) (Washington) Elk River Troy Moscow CLEARWATERCLEARWATER Kendrick Juliaetta Genesee Pierce Clearwater Peck Orofino Clarkston 17060306 Lapwai Culdesac Weippe Lewiston Asotin Reubens LEWISLEWIS Kamiah Craigmont Winchester Nezperce Kooskia Ferdinand NEZNEZ Stites PERCEPERCE Cottonwood !COEUR d ALENE MOSCOW! IDAHOIDAHO Grangeville LEWISTON! !REXBURG CALDWELL! !BOISE NAMPA! !IDAHO FALLS : BLACKFOOT ! !POCATELLO 0 5 10 15 20 25 TWIN! FALLS Miles The United States Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD). To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326W, Whitten Building, 14 th and Independence Avenue, SW, Washington DC 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer. 1 Clearwater - 17060306 Idaho 8 Digit Hydrologic Unit Profile December 2006 Introduction The Clearwater 8-Digit Hydrologic Unit Code (HUC) subbasin is 1,503,992 acres. Clearwater and Nez Perce counties each account for approximately 24 percent of the subbasin. Twenty two percent of the subbasin is in Latah County, 18 percent in Lewis County, 13 percent in Idaho County and less than 0.5% in Whitman County, Washington.
    [Show full text]