Publications
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Evidence for an ice shelf covering the central Arctic Ocean during the penultimate glaciation Evidence for an ice shelf covering the central Arctic Ocean during the penultimate glaciation
The hypothesis of a km-thick ice shelf covering the entire Arctic Ocean during peak glacial conditions was proposed nearly half a century ago. Floating ice shelves preserve few direct traces after their disappearance, making reconstructions difficult. Seafloor imprints of ice shelves should, however, exist where ice grounded along their flow paths. Here we present new evidence of ice...
Authors
Martin Jakobsson, Johan Nilsson, Leif G. Anderson, Jan Backman, Goran Bjork, Thomas M. Cronin, Nina Kirchner, Andrey Koshurnikov, Larry Mayer, Riko Noormets, Matthew O’Regan, Christian Stranne, Roman Ananiev, Natalia Barrientos Macho, Dennis Cherniykh, Helen Coxall, Bjorn Eriksson, Tom Floden, Laura Gemery, Orjan Gustafsson, Kevin Jerram, Carina Johansson, Alexey Khortov, Rezwan Mohammad, Igor Semiletov
Metaultramafic schists and dismembered ophiolites of the Ashe Metamorphic Suite of northwestern North Carolina, USA Metaultramafic schists and dismembered ophiolites of the Ashe Metamorphic Suite of northwestern North Carolina, USA
Metaultramafic rocks (MUR) in the Ashe Metamorphic Suite (AMS) of northwestern North Carolina include quartz ± feldspar-bearing QF-amphibolites and quartz-deficient, locally talc-, chlorite-, and/or Mg-amphibole-bearing TC-amphibolites. Some workers divide TC-amphibolites into Todd and Edmonds types, based on mineral and geochemical differences, and we provisionally add a third type –...
Authors
Loren A. Raymond, Arthur J. Merschat, R. Kelly Vance
Paleogeographic implications of Late Miocene lacustrine and nonmarine evaporite deposits in the Lake Mead region: Immediate precursors to the Colorado River Paleogeographic implications of Late Miocene lacustrine and nonmarine evaporite deposits in the Lake Mead region: Immediate precursors to the Colorado River
Thick late Miocene nonmarine evaporite (mainly halite and gypsum) and related lacustrine limestone deposits compose the upper basin fill in half grabens within the Lake Mead region of the Basin and Range Province directly west of the Colorado Plateau in southern Nevada and northwestern Arizona. Regional relations and geochronologic data indicate that these deposits are late...
Authors
James E. Faulds, Charlotte Schreiber, Victoria E. Langenheim, Nicholas H. Hinz, Tom Shaw, Matthew T. Heizler, Michael E Perkins, Mohammed El Tabakh, Michael J. Kunk
Structural geometry of the Valley and Ridge and Plateaus provinces Structural geometry of the Valley and Ridge and Plateaus provinces
The Valley and Ridge physiographic province comprises the area between the Blue Ridge province on the east and the Appalachian Plateau province on the west. The province consists of Paleozoic carbonate and clastic rocks that were folded and thrust faulted during the Alleghanian orogeny. The Appalachian Plateau province consists of mostly flat lying to gently dipping upper Paleozoic rocks...
Authors
Mark A. Evans, Randall C. Orndorff, William S. Henika
Awell-preserved conodont fauna from the Pennsylvanian Excello Shale of Iowa, U. S. A. Awell-preserved conodont fauna from the Pennsylvanian Excello Shale of Iowa, U. S. A.
A superbly preserved discrete element conodont fauna has been recovered from carbonate concretions from the upper Desmoinesian (Pennsylvanian) Excello Shale at two localities in south-central Iowa. The multielement apparatuses for Gondolella wardlawi (new species), Idiognathodus acutus, Idioprioniodus conjunctus, and Neognathodus roundyi are reconstructed. Rare specimens of Idiognathodus...
Authors
Merlynd K. Nestell, Bruce R. Wardlaw, John P. Pope
Petrology and tectonic history of the Green Bay Schist, Portmore, St. Catherine Parish, Jamaica Petrology and tectonic history of the Green Bay Schist, Portmore, St. Catherine Parish, Jamaica
There are three occurrences of medium- to high-grade metamorphic rocks in Jamaica: amphibolite facies Westphalia Schist, blueschist/greenschist facies Mt. Hibernia Schist, and the hitherto poorly characterized amphibolite facies Green Bay Schist. New trace element data and thermodynamic calculations show that Green Bay Schist is closely related to Westphalia Schist. The protoliths for...
Authors
Richard N. Abbott, David P. West, Betsy R. Bandy, Ryan J. McAleer
Early Mesozoic geology in Virginia Early Mesozoic geology in Virginia
No abstract available.
Authors
Joseph P. Smoot
Glacial Lake Hitchcock and the sea: Fieldtrip Guidebook for the 78th Annual Reunion of the Northeast Friends of the Pleistocene Glacial Lake Hitchcock and the sea: Fieldtrip Guidebook for the 78th Annual Reunion of the Northeast Friends of the Pleistocene
The fieldtrip will demonstrate the evidence for a close connection of Lake Hitchcock levels with lake levels and the position of sea level in Long Island Sound via a channel cut into glacial lake deposits in the lower Connecticut River valley, which issuperposed on a bedrock ridge at the mouth of the Connecticut River. On the trip we will explain important offshore features like an...
Authors
Janet Radway Stone, J.C. Ridge, Ralph S. Lewis, Mary L. DiGiacomo-Cohen
Reply Zalasiewicz et al. comment Reply Zalasiewicz et al. comment
No abstract available.
Authors
Stanley C. Finney, Lucy E. Edwards
Geology of the Mount Rogers area, revisited: Evidence of Neoproterozoic continental rifting, glaciation, and the opening and closing of the Iapetus ocean, Blue Ridge, VA–NC–TN Geology of the Mount Rogers area, revisited: Evidence of Neoproterozoic continental rifting, glaciation, and the opening and closing of the Iapetus ocean, Blue Ridge, VA–NC–TN
Recent field and geochronological studies in eight 7.5-minute quadrangles near Mount Rogers in Virginia, North Carolina and Tennessee recognize important stratigraphic and structural relationships for the Neoproterozoic Mount Rogers and Konnarock formations, the northeast end of the Mountain City window, the separation of Mesoproterozoic rocks of the Blue Ridge into three age groups, and...
Authors
Arthur J. Merschat, C. Scott Southworth, Christopher S. Holm-Denoma, Ryan J. McAleer
Geology and geomorphology of the Carolina Sandhills, Chesterfield County, South Carolina Geology and geomorphology of the Carolina Sandhills, Chesterfield County, South Carolina
This two-day field trip focuses on the geology and geomorphology of the Carolina Sandhills in Chesterfield County, South Carolina. This area is located in the updip portion of the U.S. Atlantic Coastal Plain province, supports an ecosystem of longleaf pine (Pinus palustris) and wiregrass (Aristida stricta), and contains three major geologic map units: (1) An ~60–120-m-thick unit of...
Authors
Christopher S. Swezey, Bradley A. Fitzwater, G. Richard Whittecar
Loamy, two-storied soils on the outwash plains of southwestern lower Michigan: Pedoturbation of loess with the underlying sand Loamy, two-storied soils on the outwash plains of southwestern lower Michigan: Pedoturbation of loess with the underlying sand
Soils on many of the outwash plains in southwestern Michigan have loamy upper profiles, despite being underlain by sand-textured outwash. The origin of this upper, loamy material has long been unknown. The purpose of this study is to analyze the spatio-textural characteristics of these loamy-textured sediments to ascertain their origin(s). The textural curves of this material have...
Authors
Michael D. Luehmann, Brad G. Peter, Christopher B. Connallon, Randall J. Schaetzl, Samuel J. Smidt, Wei Liu, Kevin A. Kincare, Toni A. Walkowiak, Elin Thorlund, Marie S. Holler