Imaging Laurentide Ice Sheet Drainage Into the Deep Sea: Impact on Sediments and Bottom Water
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Vegetation and Fire at the Last Glacial Maximum in Tropical South America
Past Climate Variability in South America and Surrounding Regions Developments in Paleoenvironmental Research VOLUME 14 Aims and Scope: Paleoenvironmental research continues to enjoy tremendous interest and progress in the scientific community. The overall aims and scope of the Developments in Paleoenvironmental Research book series is to capture this excitement and doc- ument these developments. Volumes related to any aspect of paleoenvironmental research, encompassing any time period, are within the scope of the series. For example, relevant topics include studies focused on terrestrial, peatland, lacustrine, riverine, estuarine, and marine systems, ice cores, cave deposits, palynology, iso- topes, geochemistry, sedimentology, paleontology, etc. Methodological and taxo- nomic volumes relevant to paleoenvironmental research are also encouraged. The series will include edited volumes on a particular subject, geographic region, or time period, conference and workshop proceedings, as well as monographs. Prospective authors and/or editors should consult the series editor for more details. The series editor also welcomes any comments or suggestions for future volumes. EDITOR AND BOARD OF ADVISORS Series Editor: John P. Smol, Queen’s University, Canada Advisory Board: Keith Alverson, Intergovernmental Oceanographic Commission (IOC), UNESCO, France H. John B. Birks, University of Bergen and Bjerknes Centre for Climate Research, Norway Raymond S. Bradley, University of Massachusetts, USA Glen M. MacDonald, University of California, USA For futher -
The Cordilleran Ice Sheet 3 4 Derek B
1 2 The cordilleran ice sheet 3 4 Derek B. Booth1, Kathy Goetz Troost1, John J. Clague2 and Richard B. Waitt3 5 6 1 Departments of Civil & Environmental Engineering and Earth & Space Sciences, University of Washington, 7 Box 352700, Seattle, WA 98195, USA (206)543-7923 Fax (206)685-3836. 8 2 Department of Earth Sciences, Simon Fraser University, Burnaby, British Columbia, Canada 9 3 U.S. Geological Survey, Cascade Volcano Observatory, Vancouver, WA, USA 10 11 12 Introduction techniques yield crude but consistent chronologies of local 13 and regional sequences of alternating glacial and nonglacial 14 The Cordilleran ice sheet, the smaller of two great continental deposits. These dates secure correlations of many widely 15 ice sheets that covered North America during Quaternary scattered exposures of lithologically similar deposits and 16 glacial periods, extended from the mountains of coastal south show clear differences among others. 17 and southeast Alaska, along the Coast Mountains of British Besides improvements in geochronology and paleoenvi- 18 Columbia, and into northern Washington and northwestern ronmental reconstruction (i.e. glacial geology), glaciology 19 Montana (Fig. 1). To the west its extent would have been provides quantitative tools for reconstructing and analyzing 20 limited by declining topography and the Pacific Ocean; to the any ice sheet with geologic data to constrain its physical form 21 east, it likely coalesced at times with the western margin of and history. Parts of the Cordilleran ice sheet, especially 22 the Laurentide ice sheet to form a continuous ice sheet over its southwestern margin during the last glaciation, are well 23 4,000 km wide. -
Spatial Variability of Levees As Measured Using the CPT
2nd International Symposium on Cone Penetration Testing, Huntington Beach, CA, USA, May 2010 Spatial Variability of Levees as Measured Using the CPT R.E.S. Moss Assistant Professor, Cal Poly, San Luis Obispo J. C. Hollenback Graduate Researcher, U.C. Berkeley J. Ng Undergraduate Researcher, Cal Poly, San Luis Obispo ABSTRACT: The spatial variability of a soil deposit is something that is commonly discussed but difficult to quantify. The heterogeneity as a function of lateral distance can be critical to the design of long engineered structures such as highways, bridges, levees, and other lifelines. This paper presents a methodology for using CPT mea- surements to quantifying the spatial variability of cone tip resistance along a levee in the California Bay Delta. The results, presented in the form of a general relative va- riogram, identify the distance at which the maximum spatial variability is achieved for a given soil strata. This information helps define minimally correlated stretches of levee for proper failure and risk analysis. Presented herein are methods of interpret- ing, calculating, and analyzing CPT data to arrive at the quantified spatial variability with respect to different static and seismic failure modes common to levee systems. 1 INTRODUCTION Spatial variability of engineering properties in soil strata is inherent to the nature of soil. Spatial variability is controlled primarily by the depositional environment where high energy systems usually deposit materials with high spatial variability (e.g. al- luvial gravels) and low energy systems usually deposit materials with low spatial va- riability (e.g. lacustrine clays). This spatial variability is generally taken into account in geotechnical design in a qualitative empirical manner through appropriately spaced borings to assess the changing subsurface conditions. -
Oxygen Isotope Geochemistry of Laurentide Ice-Sheet Meltwater Across Termination I
Quaternary Science Reviews 178 (2017) 102e117 Contents lists available at ScienceDirect Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I * Lael Vetter a, , Howard J. Spero a, Stephen M. Eggins b, Carlie Williams c, Benjamin P. Flower c a Department of Earth and Planetary Sciences, University of California Davis, Davis, CA 95616, USA b Research School of Earth Sciences, The Australian National University, Canberra 0200, ACT, Australia c College of Marine Sciences, University of South Florida, St. Petersburg, FL 33701, USA article info abstract Article history: We present a new method that quantifies the oxygen isotope geochemistry of Laurentide ice-sheet (LIS) Received 3 April 2017 meltwater across the last deglaciation, and reconstruct decadal-scale variations in the d18O of LIS Received in revised form meltwater entering the Gulf of Mexico between ~18 and 11 ka. We employ a technique that combines 1 October 2017 laser ablation ICP-MS (LA-ICP-MS) and oxygen isotope analyses on individual shells of the planktic Accepted 4 October 2017 18 foraminifer Orbulina universa to quantify the instantaneous d Owater value of Mississippi River outflow, which was dominated by meltwater from the LIS. For each individual O. universa shell, we measure Mg/ Ca (a proxy for temperature) and Ba/Ca (a proxy for salinity) with LA-ICP-MS, and then analyze the same 18 18 O. universa for d O using the remaining material from the shell. From these proxies, we obtain d Owater and salinity estimates for each individual foraminifer. Regressions through data obtained from discrete 18 18 core intervals yield d Ow vs. -
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Bildnachweis Im Bildnachweis verwendete Abkürzungen: With permission from the Geological Society of Ame- rica l – links; m – Mitte; o – oben; r – rechts; u – unten 4.65; 6.52; 6.183; 8.7 Bilder ohne Nachweisangaben stammen vom Autor. Die Autoren der Bildquellen werden in den Bildunterschriften With permission from the Society for Sedimentary genannt; die bibliographischen Angaben sind in der Literaturlis- Geology (SEPM) te aufgeführt. Viele Autoren/Autorinnen und Verlage/Institutio- 6.2ul; 6.14; 6.16 nen haben ihre Einwilligung zur Reproduktion von Abbildungen gegeben. Dafür sei hier herzlich gedankt. Für die nachfolgend With permission from the American Association for aufgeführten Abbildungen haben ihre Zustimmung gegeben: the Advancement of Science (AAAS) Box Eisbohrkerne Dr; 2.8l; 2.8r; 2.13u; 2.29; 2.38l; Box Die With permission from Elsevier Hockey-Stick-Diskussion B; 4.65l; 4.53; 4.88mr; Box Tuning 2.64; 3.5; 4.6; 4.9; 4.16l; 4.22ol; 4.23; 4.40o; 4.40u; 4.50; E; 5.21l; 5.49; 5.57; 5.58u; 5.61; 5.64l; 5.64r; 5.68; 5.86; 4.70ul; 4.70ur; 4.86; 4.88ul; Box Tuning A; 4.95; 4.96; 4.97; 5.99; 5.100l; 5.100r; 5.118; 5.119; 5.123; 5.125; 5.141; 5.158r; 4.98; 5.12; 5.14r; 5.23ol; 5.24l; 5.24r; 5.25; 5.54r; 5.55; 5.56; 5.167l; 5.167r; 5.177m; 5.177u; 5.180; 6.43r; 6.86; 6.99l; 6.99r; 5.65; 5.67; 5.70; 5.71o; 5.71ul; 5.71um; 5.72; 5.73; 5.77l; 5.79o; 6.144; 6.145; 6.148; 6.149; 6.160; 6.162; 7.18; 7.19u; 7.38; 5.80; 5.82; 5.88; 5.94; 5.94ul; 5.95; 5.108l; 5.111l; 5.116; 5.117; 7.40ur; 8.19; 9.9; 9.16; 9.17; 10.8 5.126; 5.128u; 5.147o; 5.147u; -
Glaciation of Wisconsin Educational Series 36 | 2011 Fourth Edition
WISCONSIN GEOLOGICAL AND NATURAL HISTORY SURVEY Glaciation of Wisconsin Educational Series 36 | 2011 Fourth edition For the past 2.5 million years, Earth’s climate has fluctuated During the last part of the Wisconsin Glaciation, the between conditions of warm and cold. These cycles are the Laurentide Ice Sheet expanded southward into the Midwest result of changes in the shape of the Earth’s orbit and the tilt as far as Indiana, Illinois, and Iowa. The ice sheet advanced of the Earth’s axis. The colder periods allowed the growth of to its maximum extent by about 30,000 years ago and didn’t glaciers that covered large parts of the world’s high altitude melt back until thousands of years later. It readvanced a and high latitude areas. number of times before finally disappearing from Wisconsin about 11,000 years ago. Many of the state’s most prominent The last cycle of climate cooling and glacier expansion in landscape features were formed during the last part of the North America is known as the Wisconsin Glaciation. About Wisconsin Glaciation. 100,000 years ago, the climate cooled and a glacier, the Laurentide Ice Sheet, began to cover northern North America. The maps and diagrams in this publication show the tim- For the first 70,000 years the ice sheet expanded and con- ing and location of major ice-margin positions as well as the tracted but did not enter what is now Wisconsin. distribution of the glacial and related stratigraphic units that were deposited in Wisconsin. Tracking the glacier Maps showing the extent of the Laurentide Ice Sheet and changes to glacial lakes at several times. -
Summary of the Hudson Bay Marine Ecosystem Overview
i SUMMARY OF THE HUDSON BAY MARINE ECOSYSTEM OVERVIEW by D.B. STEWART and W.L. LOCKHART Arctic Biological Consultants Box 68, St. Norbert P.O. Winnipeg, Manitoba CANADA R3V 1L5 for Canada Department of Fisheries and Oceans Central and Arctic Region, Winnipeg, Manitoba R3T 2N6 Draft March 2004 ii Preface: This report was prepared for Canada Department of Fisheries and Oceans, Central And Arctic Region, Winnipeg. MB. Don Cobb and Steve Newton were the Scientific Authorities. Correct citation: Stewart, D.B., and W.L. Lockhart. 2004. Summary of the Hudson Bay Marine Ecosystem Overview. Prepared by Arctic Biological Consultants, Winnipeg, for Canada Department of Fisheries and Oceans, Winnipeg, MB. Draft vi + 66 p. iii TABLE OF CONTENTS 1.0 INTRODUCTION.........................................................................................................................1 2.0 ECOLOGICAL OVERVIEW.........................................................................................................3 2.1 GEOLOGY .....................................................................................................................4 2.2 CLIMATE........................................................................................................................6 2.3 OCEANOGRAPHY .........................................................................................................8 2.4 PLANTS .......................................................................................................................13 2.5 INVERTEBRATES AND UROCHORDATES.................................................................14 -
Part 629 – Glossary of Landform and Geologic Terms
Title 430 – National Soil Survey Handbook Part 629 – Glossary of Landform and Geologic Terms Subpart A – General Information 629.0 Definition and Purpose This glossary provides the NCSS soil survey program, soil scientists, and natural resource specialists with landform, geologic, and related terms and their definitions to— (1) Improve soil landscape description with a standard, single source landform and geologic glossary. (2) Enhance geomorphic content and clarity of soil map unit descriptions by use of accurate, defined terms. (3) Establish consistent geomorphic term usage in soil science and the National Cooperative Soil Survey (NCSS). (4) Provide standard geomorphic definitions for databases and soil survey technical publications. (5) Train soil scientists and related professionals in soils as landscape and geomorphic entities. 629.1 Responsibilities This glossary serves as the official NCSS reference for landform, geologic, and related terms. The staff of the National Soil Survey Center, located in Lincoln, NE, is responsible for maintaining and updating this glossary. Soil Science Division staff and NCSS participants are encouraged to propose additions and changes to the glossary for use in pedon descriptions, soil map unit descriptions, and soil survey publications. The Glossary of Geology (GG, 2005) serves as a major source for many glossary terms. The American Geologic Institute (AGI) granted the USDA Natural Resources Conservation Service (formerly the Soil Conservation Service) permission (in letters dated September 11, 1985, and September 22, 1993) to use existing definitions. Sources of, and modifications to, original definitions are explained immediately below. 629.2 Definitions A. Reference Codes Sources from which definitions were taken, whole or in part, are identified by a code (e.g., GG) following each definition. -
Orbital Control of Productivity and of Sea-Ice Production/Drifting in the Central Arctic Ocean During the Late Quaternary
Geophysical Research Abstracts Vol. 21, EGU2019-1743, 2019 EGU General Assembly 2019 © Author(s) 2018. CC Attribution 4.0 license. Orbital control of productivity and of sea-ice production/drifting in the central Arctic Ocean during the late Quaternary Claude Hillaire-Marcel (1), Anne de Vernal (1), Yanguang Liu (2), Jenny Maccali (3), Karl Purcell (1), Bassam Ghaleb (1), Allison Jacobel (4), Rüdiger Stein (5), Jerry McManus (4), and Michel Crucifix (6) (1) GEOTOP-UQAM, Université du Québec, Montreal, Canada ([email protected]), (2) First Institute of Oceanography, State Oceanic Administration, Qingdao, China (yanguangliu@fio.org.cn), (3) Department of Earth Sciences, University of Bergen, Norway ([email protected]), (4) Lamont-Doherty Earth Observatory of Columbia University, New-York, USA ([email protected]), (5) Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany ([email protected]), (6) ELIC, Université catholique de Louvain, Louvain-la-Neuve, Belgium (michel.crucifi[email protected]) The recently revised chronostratigraphy of the central Arctic Ocean sedimentary sequences (https://doi.org/10.1002/2017GC007050) provides the means to insert the Arctic paleoceanography into the Earth’s global climate history. Based on magnetostratigraphy, 14C ages and 230Th-231Pa excess extinction ages in a series of sedimentary cores raised from the Mendeleev and Lomonosov ridges by the R/V Polarstern, Healy and MV Xue Long ice-breakers, with chronological complementary information from pre-2000 studies, we have been able to estimate sedimentation rates ranging from less than a few mm/ka to a few cm/ka along these ridges, with the highest accumulation rates eastward, near the ice-factories of the Russian shelf. -
Who Discovered the Northwest Passage? Janice Cavell1
ARCTIC VOL. 71, NO.3 (SEPTEMBER 2018) P.292 – 308 https://doi.org/10.14430/arctic4733 Who Discovered the Northwest Passage? Janice Cavell1 (Received 31 January 2018; accepted in revised form 1 May 2018) ABSTRACT. In 1855 a parliamentary committee concluded that Robert McClure deserved to be rewarded as the discoverer of a Northwest Passage. Since then, various writers have put forward rival claims on behalf of Sir John Franklin, John Rae, and Roald Amundsen. This article examines the process of 19th-century European exploration in the Arctic Archipelago, the definition of discovering a passage that prevailed at the time, and the arguments for and against the various contenders. It concludes that while no one explorer was “the” discoverer, McClure’s achievement deserves reconsideration. Key words: Northwest Passage; John Franklin; Robert McClure; John Rae; Roald Amundsen RÉSUMÉ. En 1855, un comité parlementaire a conclu que Robert McClure méritait de recevoir le titre de découvreur d’un passage du Nord-Ouest. Depuis lors, diverses personnes ont avancé des prétentions rivales à l’endroit de Sir John Franklin, de John Rae et de Roald Amundsen. Cet article se penche sur l’exploration européenne de l’archipel Arctique au XIXe siècle, sur la définition de la découverte d’un passage en vigueur à l’époque, de même que sur les arguments pour et contre les divers prétendants au titre. Nous concluons en affirmant que même si aucun des explorateurs n’a été « le » découvreur, les réalisations de Robert McClure méritent d’être considérées de nouveau. Mots clés : passage du Nord-Ouest; John Franklin; Robert McClure; John Rae; Roald Amundsen Traduit pour la revue Arctic par Nicole Giguère. -
Canadian Arctic Tide Measurement Techniques and Results
International Hydrographie Review, Monaco, LXIII (2), July 1986 CANADIAN ARCTIC TIDE MEASUREMENT TECHNIQUES AND RESULTS by B.J. TAIT, S.T. GRANT, D. St.-JACQUES and F. STEPHENSON (*) ABSTRACT About 10 years ago the Canadian Hydrographic Service recognized the need for a planned approach to completing tide and current surveys of the Canadian Arctic Archipelago in order to meet the requirements of marine shipping and construction industries as well as the needs of environmental studies related to resource development. Therefore, a program of tidal surveys was begun which has resulted in a data base of tidal records covering most of the Archipelago. In this paper the problems faced by tidal surveyors and others working in the harsh Arctic environment are described and the variety of equipment and techniques developed for short, medium and long-term deployments are reported. The tidal characteris tics throughout the Archipelago, determined primarily from these surveys, are briefly summarized. It was also recognized that there would be a need for real time tidal data by engineers, surveyors and mariners. Since the existing permanent tide gauges in the Arctic do not have this capability, a project was started in the early 1980’s to develop and construct a new permanent gauging system. The first of these gauges was constructed during the summer of 1985 and is described. INTRODUCTION The Canadian Arctic Archipelago shown in Figure 1 is a large group of islands north of the mainland of Canada bounded on the west by the Beaufort Sea, on the north by the Arctic Ocean and on the east by Davis Strait, Baffin Bay and Greenland and split through the middle by Parry Channel which constitutes most of the famous North West Passage. -
Documentation of Design Deficiencies Santa Clara River Levee System (Scr-1) 1
DOCUMENTATION OF DESIGN DEFICIENCIES SANTA CLARA RIVER LEVEE SYSTEM (SCR-1) 1. Project Description and Watershed Characteristics The Santa Clara River Levee (SCR-1) system is located in the city of Oxnard, in Ventura County, California. It is approximately 4.72 miles long, extending along the southeast bank of the Santa Clara River from Highway 101, at its downstream terminus, to the community of Saticoy, at its upstream terminus (see Figure 1). SCR-1 was originally designed in 1958 by the U.S. Army Corps of Engineers (Corps) to control the Corps’ predicted Standard Project Flood peak discharge of 225,000 cubic feet per second (cfs), a peak emanating from a partially regulated 1,600-square-mile Santa Clara River watershed. The height of SCR-1 varies from approximately 4 feet to 13 feet. The compacted fill embankment that forms SCR-1 has a top width of 18 feet. The levee embankment slopes are 2 horizontal to 1 vertical (2H:1V), on both the landward side and the riverward side. The riverward side of the embankment has a 1.5- to 2- foot-thick rock revetment, with a concrete facing at and near highway bridges. The rock revetment extends from the top of the embankment to varying depths. The lowest depth of the rock revetment is hereinafter referred to as the “toedown.” Construction of the SCR-1 project was completed in 1961. The levee was constructed adjacent to the active channel of the Santa Clara River. A review of historical aerial photography, dating as far back as 1927, indicates that before construction of the SCR-1, there were numerous locations along the project reach where the primary braid of the Santa Clara River impinged directly on the east and west banks of the river at rather abrupt flow angles.