Papers by Scott Lundstrom
Qayy Youngest fan alluvium (Holocene)--Noncemented alluvial-fan gravel, with interbedded sands; p... more Qayy Youngest fan alluvium (Holocene)--Noncemented alluvial-fan gravel, with interbedded sands; poorly to moderately well sorted; massive to well bedded; clast-supported to matrix-supported. Gravel is angular to subrounded, ranging in size from granules to boulders, and composed predominantly of carbonate lithologies derived from erosion of the Paleozoic section. Includes deposits of abundant modern channels that are too narrow (less than 30 m) to map separately, as well as Holocene deposits between modern channels. Etching on surficial limestone clasts ranges from absent on deposits of modern channels to incipient and sparse on deposits between modern channels. Bar-and-swale depositional morphology ranges from prominent in modern channels, to variably modified and muted by addition of eolian sediment in areas between modern channels. Desert pavement ranges from absent on deposits of modern channels, to loosely packed and weakly developed on deposits between active channels. Rock va...
DOE Scientific and Technical Information. DOE Scientific and Technical Information. ...
Quaternary International, 2012
Clastic cave sediments form in sheltered environments, collect material from airborne, water, and... more Clastic cave sediments form in sheltered environments, collect material from airborne, water, and faunal sources, and are important to archaeology and palaeontology. Novel tools for palaeoenvironmental reconstruction in this context are therefore of interest to Quaternary research. This study forms the first comprehensive investigation of lipid biomarkers preserved in cave sediments. Lipid biomarkers are molecules such as plant waxes, which derive from living organisms, therefore forming a valuable tool for investigating changes in past ecosystems, independent of and complementary to existing techniques such as pollen analysis. Lipid biomarkers have been recovered from samples from two caves in Vietnam; Hang Boi, and Hang Trong. These sites which lie in the Ninh Bình province are both dominated by anthropogenic shell middens interspersed with sedimentation from windblown sands and bedrock breakdown. Hang Boi is an open cave situated at 78m a.s.l.; radiocarbon dates from charcoal from the section indicate the sediment ranges from 12,100cal. yrs. b.p. to 12,400cal. yrs. b.p. at the base, approximately 1 m depth. The second site, Hang Trong, is situated 142m a.s.l. and has two openings on opposite sides of a karst tower making it a good site to investigate airborne deposition. Radiocarbon dates from charcoal indicate the sub-surface sediment is recent and at approximately 1.5m from the surface, 18,500yrs. b.p. A wide range of compounds have been found, including those derived from plants, midden shells, and microbes. Stratigraphic sequences, covering 300 years from Hang Boi and 20,000 years from Hang Trong, demonstrate how the biomarkers change through time. Future work will focus on investigating the integrity of the proxy, especially post-depositional movement of organic molecules. To address this, compound-specific radiocarbon dating, will be used to investigate the ages of different biomarkers compared to the established chronology.
Scientific Investigations Map
This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey e... more This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic code. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government
For an overview of USGS information products, including maps, imagery, and publications, visit ht... more For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.
ably the penultimate major wet-climate periods. Spring deposits at Crater Flat and at the Lathrop... more ably the penultimate major wet-climate periods. Spring deposits at Crater Flat and at the Lathrop Wells Diatomite 20 krn south of Yucca Mountain and paleowetland deposits near the Amargosa River show that discharge occurred between about 40,000 and 8,000 years before the present. The discharge, at least in part, came from the regional aquifer when the water tables rose to a maximum of about 100 m above present levels, as indicated from the depth to regional ground water at the Lathrop Wells diatomite site.
Portions of this document may be illegible electronic image products. Images are produced from th... more Portions of this document may be illegible electronic image products. Images are produced from the best available original document.
Detailed studies of trenches 14D and 14C on the Bow Ridge fault indicate two to three displacemen... more Detailed studies of trenches 14D and 14C on the Bow Ridge fault indicate two to three displacements and long recurrence intervals during the middle to late Quaternary. The main trace of the fault is marked by a thick (20--40 centimeters wide) subvertical shear zone coated with multiple carbonate-silica laminae and several generations of fine-grained fissure-fill debris. Exposed in the trenches
Open-File Report
This map is preliminary and has not been reviewed for conformity with U.S. Geological Survey edit... more This map is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature Description of map units [Descriptive colors for map units are from the Rock-Color Chart Committee (1951) Qayy Youngest fan alluvium (Holocene)-Noncemented alluvial-fan gravel, with interbedded sands; poorly to moderately well sorted; massive to well bedded; clast-supported to matrix-supported. Gravel is angular to subrounded, ranging in size from granules to boulders, and composed predominantly of carbonate lithologies derived from erosion of the Paleozoic section. Includes deposits of abundant modern channels that are too narrow (less than 30 m) to map separately, as well as Holocene deposits between modern channels. Etching on surficial limestone clasts ranges from absent on deposits of modern channels to incipient and sparse on deposits between modern channels. Bar-and-swale depositional morphology ranges from prominent in modern channels, to variably modified and muted by addition of eolian sediment in areas between modern channels. Desert pavement ranges from absent on deposits of modern channels, to loosely packed and weakly developed on deposits between active channels. Rock varnish, which does not form on many common limestone clasts, is generally very weakly developed to absent on more siliceous lithologies (including siliceous carbonates) except for relict rock varnish not abraded during transport. Typical non-cemented and weak soil development is characterized by the presence of stage I-II secondary carbonate morphology (mostly thin coats on clast undersides), and by a gradual increase of sand toward the surface through the upper 10 to 30 cm of the unit. The surficial sand component is considered to be a pedogenically mixed and infiltrated eolian sediment deposited after fluvial deposition of fan gravel. Minimum thickness is 1-2 m; base of unit is generally not exposed. Qay Young fan alluvium (Holocene and latest Pleistocene)~Noncemented alluvial-fan gravel, with interbedded sands; poorly to moderately well sorted; massive to well bedded; clast-supported to matrix-supported. Gravel is angular to subrounded, ranging in size from granules to boulders, and composed predominantly of carbonate lithologies derived from erosion of the Paleozoic section. Includes deposits in common modern channels that are too narrow (less than 30 m) to map separately, as well as Holocene and locally latest Pleistocene (younger than about 15 ka) deposits between modern channels. Etching on surficial limestone clasts ranges from absent on deposits of modern channels to incipient and sparse to moderately developed and common on deposits between modern channels. Bar-and-swale depositional morphology ranges from prominent in modern channels, to variably modified and muted by addition of eolian sediment in areas between modern channels. Even in the most muted cases, cobbles and boulders protrude from eolian sand cover, and relict depositional microrelief is evident on aerial photographs. Desert pavement ranges from absent on deposits in modern channels, to loosely packed and weakly developed (especially in areas of relatively low dust-flux, as on the upper part of the fan) to moderately well packed in areas of higher dust flux, such as the lower southern ends of the fans which are more proximal to fine grained eolian source areas of the Las Vegas Valley. Rock varnish, which does not form on many common limestone clasts, is generally weakly developed to absent on more siliceous lithologies (including siliceous carbonates) except for relict rock varnish not abraded during transport. Typical non-cemented and weak soil development is characterized by a cambic Bw horizon, by the presence of stage I-II secondary carbonate morphology (mostly thin coats on clast undersides), and by a gradual increase of sand toward the surface through the top 0.5 m of the deposit. The surficial sand component is considered to be a
Scientific Investigations Map
Open-File Report
Geologic mapping studies are underway to help define the geologic framework for integrated ecosys... more Geologic mapping studies are underway to help define the geologic framework for integrated ecosystem and climate change research in the Greater Platte River Basins, an ecoregion being targeted for collaborative observation and research by the Climate Effects Network (CEN) of the U.S. Geological Survey (USGS) Global Change Program. Geologic mapping and associated geochronological research provide information about physical and chemical properties, distribution, age, origin, and stratigraphic relations of surficial geologic deposits for reconstructing geologic and hydrologic history and for recognizing geomorphic response to climate change that is recorded in the geologic record. Planned surficial geologic mapping and research under the new "Greater Platte River Basins and Northern Plains Geologic Framework Studies Project" primarily focuses on three areas: (1) the South Platte River on the drought-prone eastern plains of Colorado, a semiarid environment where geomorphic systems tend to be highly sensitive to climate change; (2) the Niobrara National Scenic River in northern Nebraska, situated at the crossroads of several ecosystems, where many plant and animal species are near the limits of their usual geographic range, and geomorphic systems may be near threshold limits; and (3) the Crescent Lake Wildlife Refuge area in the western Nebraska Sand Hills, where dune migration during past episodes of eolian sand activity blocked stream drainages and created numerous lakes. In each of these areas, the geologic records of fluvial and eolian systems are intimately connected and reflective of past climate change. Large-scale geologic mapping in these areas, which will complement ongoing studies by other researchers, will lead to a better understanding of how climate change has affected the geomorphic systems in the past, and how it might affect them in the future. This information is vital to preserving and sustaining healthy human and wildlife habitats, adequate water supplies, and operational infrastructure. Planned hydrogeologic framework studies under the new "Greater Platte River Basins and Northern Plains Geologic Framework Studies Project" focus primarily on groundwater issues in a fourth area, the Republican River drainage of southern Nebraska and northern Kansas. Sustainability of water in the basin has been a key topic of concern between states sharing the water supply, a concern intensified by the possibility of further diminishing water resources as climate changes. New digital geologic mapping of selected areas will improve understanding of the complex geologic framework that affects groundwater flow and groundwater-surface water interactions in and around the basin, and help address the major issue of water sustainability.
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Papers by Scott Lundstrom