Publications
Filter Total Items: 897
Soils as relative-age dating tools Soils as relative-age dating tools
Soils develop at the earth's surface via multiple processes that act through time. Precluding burial or disturbance, soil genetic horizons form progressively and reflect the balance among formation processes, surface age, and original substrate composition. Soil morphology provides a key link between process and time (soil age), enabling soils to serve as both relative and numerical...
Authors
Helaine W. Markewich, Milan J. Pavich, Douglas A. Wysocki
Application of molluscan analyses to the reconstruction of past environmental conditions in estuaries Application of molluscan analyses to the reconstruction of past environmental conditions in estuaries
Molluscs possess a number of attributes that make them an excellent source of past environmental conditions in estuaries: they are common in estuarine environments; they typically have hard shells and are usually well preserved in sediments; they are relatively easy to detect in the environment; they have limited mobility as adults; they grow by incremental addition of layers to their...
Authors
G. Lynn Wingard, Donna Surge
Olivine-melt relationships and syneruptive redox variations in the 1959 eruption of Kīlauea Volcano as revealed by XANES Olivine-melt relationships and syneruptive redox variations in the 1959 eruption of Kīlauea Volcano as revealed by XANES
The 1959 summit eruption of Kīlauea Volcano exhibited high lava fountains of gas-rich, primitive magma, containing olivine + chromian spinel in highly vesicular brown glass. Microprobe analysis of these samples shows that euhedral rims on olivine phenocrysts, in direct contact with glass, vary significantly in forsterite (Fo) content, at constant major-element melt composition, as do...
Authors
Rosalind L. Helz, Elizabeth Cottrell, Maryjo N. Brounce, Katherine A. Kelley
Geologic controls on cave development in Burnsville Cove, Bath and Highland Counties, Virginia Geologic controls on cave development in Burnsville Cove, Bath and Highland Counties, Virginia
Burnsville Cove in Bath and Highland Counties (Virginia, USA) is a karst region in the Valley and Ridge Province of the Appalachian Mountains. The region contains many caves in Silurian to Devonian limestone, and is well suited for examining geologic controls on cave location and cave passage morphology. In Burnsville Cove, many caves are located preferentially near the axes of synclines...
Authors
Christopher S. Swezey, John T. Haynes, Philip C. Lucas, Richard A. Lambert
Cosmogenic nuclide age estimate for Laurentide Ice Sheet recession from the terminal moraine, New Jersey, USA, and constraints on latest Pleistocene ice sheet history Cosmogenic nuclide age estimate for Laurentide Ice Sheet recession from the terminal moraine, New Jersey, USA, and constraints on latest Pleistocene ice sheet history
The time at which the Laurentide Ice Sheet reached its maximum extent and subsequently retreated from its terminal moraine in New Jersey has been constrained by bracketing radiocarbon ages on preglacial and postglacial sediments. Here, we present measurements of in situ produced 10Be and 26Al in 16 quartz-bearing samples collected from bedrock outcrops and glacial erratics just north of...
Authors
Lee B. Corbett, Paul R. Bierman, Byron D. Stone, Marc W. Caffee, Patrick L. Larsen
North American Commission on Stratigraphic Nomenclature Report 12 – Revision of article 37, lithodemic units, of the North American Stratigraphic Code North American Commission on Stratigraphic Nomenclature Report 12 – Revision of article 37, lithodemic units, of the North American Stratigraphic Code
At the 71st Annual Meeting of the North American Commission on Stratigraphic Nomenclature, 26 September, 2016, in Denver, Colorado, the Commission voted unanimously to accept the revision of Article 37 of the North American Stratigraphic Code (North American Commission on Stratigraphic Nomenclature, 2005), printed below. It replaces all older versions of this Article. An application for...
Authors
Robert M. Easton, Lucy E. Edwards, Randall C. Orndorff, Manuel Duguet, Ismael Ferrusquia-Villafranca
The 3.6 ka Aniakchak tephra in the Arctic Ocean: A constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea The 3.6 ka Aniakchak tephra in the Arctic Ocean: A constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea
The caldera-forming eruption of the Aniakchak volcano in the Aleutian Range on the Alaskan Peninsula at 3.6 cal kyr BP was one of the largest Holocene eruptions worldwide. The resulting ash is found as a visible sediment layer in several Alaskan sites and as a cryptotephra on Newfoundland and Greenland. This large geographic distribution, combined with the fact that the eruption is...
Authors
Christof Pearce, Aron Varhelyi, Stefan Wastegard, Francesco Muschitiello, Natalia Barrientos Macho, Matt O’Regan, Thomas M. Cronin, Laura Gemery, Igor Semiletov, Jan Backman, Martin Jakobsson
Creating high-resolution bare-earth digital elevation models (DEMs) from stereo imagery in an area of densely vegetated deciduous forest using combinations of procedures designed for lidar point cloud filtering Creating high-resolution bare-earth digital elevation models (DEMs) from stereo imagery in an area of densely vegetated deciduous forest using combinations of procedures designed for lidar point cloud filtering
For areas of the world that do not have access to lidar, fine-scale digital elevation models (DEMs) can be photogrammetrically created using globally available high-spatial resolution stereo satellite imagery. The resultant DEM is best termed a digital surface model (DSM) because it includes heights of surface features. In densely vegetated conditions, this inclusion can limit its...
Authors
Jessica D. DeWitt, Timothy A. Warner, Peter G. Chirico, Sarah E. Bergstresser
Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands
Permafrost peatlands store one-third of the total carbon (C) in the atmosphere and are increasingly vulnerable to thaw as high-latitude temperatures warm. Large uncertainties remain about C dynamics following permafrost thaw in boreal peatlands. We used a chronosequence approach to measure C stocks in forested permafrost plateaus (forest) and thawed permafrost bogs, ranging in thaw age...
Authors
Miriam C. Jones, Jennifer W. Harden, Jonathan A. O’Donnell, Kristen L. Manies, M. Torre Jorgenson, Claire C. Treat, Stephanie Ewing
Reply to: Terry, J. and Goff, J. comment on “Late Cenozoic sea level and the rise of modern rimmed atolls” by Toomey et al. (2016), Palaeogeography, Palaeoclimatology, Palaeoecology 4 51: 73–83. Reply to: Terry, J. and Goff, J. comment on “Late Cenozoic sea level and the rise of modern rimmed atolls” by Toomey et al. (2016), Palaeogeography, Palaeoclimatology, Palaeoecology 4 51: 73–83.
We appreciate Terry and Goff's thoughtful comment in response to our proposed atoll development model. Flank collapse of reef-built slopes likely does affect plan-form atoll morphology in some locations and potentially poses a tsunami hazard to low-lying Pacific islands (Terry and Goff, 2013). However, given the often rapid rates of lagoon infill (> 1 mm/yr; Montaggioni, 2005), such...
Authors
Michael Toomey, Andrew Ashton, Maureen E. Raymo, J. Taylor Perron
Extended late Holocene relative sea-level histories for North Carolina, USA Extended late Holocene relative sea-level histories for North Carolina, USA
We produced ∼3000-year long relative sea-level (RSL) histories for two sites in North Carolina (USA) using foraminifera preserved in new and existing cores of dated salt-marsh sediment. At Cedar Island, RSL rose by ∼2.4 m during the past ∼3000 years compared to ∼3.3 m at Roanoke Island. This spatial difference arises primarily from differential GIA that caused late Holocene RSL rise to...
Authors
Andrew C. Kemp, Jessica J. Kegel, Stephen J. Culver, Donald C. Barber, David J. Mallinson, Eduardo Leorri, Christopher E. Bernhardt, Niamh Cahill, Stanley R. Riggs, Anna L. Woodson, Ryan P. Mulligan, Benjamin P. Horton
Book review: Karst without boundaries Book review: Karst without boundaries
No abstract available.
Authors
Daniel H. Doctor