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Articles 23611 - 23640 of 29957
Full-Text Articles in Geology
Carbon Cycling Dynamics Inferred From Carbon Isotope Sourcing In A Mid-Latitude Karst-Influenced River, Kegan N. Mcclanahan
Carbon Cycling Dynamics Inferred From Carbon Isotope Sourcing In A Mid-Latitude Karst-Influenced River, Kegan N. Mcclanahan
Masters Theses & Specialist Projects
As ever-increasing levels of carbon dioxide alter the chemistry of the Earth’s atmosphere, understanding the global carbon cycle becomes increasingly important. A particularly important component is the riverine carbon cycle, as rivers are the primary conduits for dissolved inorganic carbon from terrestrial watersheds to ocean basins. Stable carbon isotopes (13C/12C) were collected weekly and input into the mixing model IsoSource to delineate seasonal carbon sourcing along two nested basins in the upper Green River System, Kentucky. In the more siliciclastic upstream catchment, dissolved inorganic carbon (DIC) was primarily derived from soil respiration (34%). Groundwater dissolving carbonate bedrock and carbonate dissolution/precipitation …
Investigation Of The Flow And Fate Of Nitrate In Epikarst At The Savoy Experimental Watershed, Northwest Arkansas, Jozef Laincz
Investigation Of The Flow And Fate Of Nitrate In Epikarst At The Savoy Experimental Watershed, Northwest Arkansas, Jozef Laincz
Graduate Theses and Dissertations
Many karst aquifers are at high risk of nitrate contamination due to a combination of vulnerable geology characterized by thin soils and conduit flow, and excess inputs of nutrients from animal feeding operations. One zone that is present in many karst regions and could play an important role in nitrate attenuation due to properties such as increased residence time and matrix-water contact is the upper, weathered portion of karst, the epikarst. However, the understanding of this role is lacking, and the objective of this dissertation was to elucidate it. The fate of nitrate in the epikarst was traced along a …
Time, Money, And Melting Ice: Proposal For A Coopertive Study Of The World’S Cave Ice In A Race Against Climate Change, George Veni, Lewis Land, Aurel Perşoiu
Time, Money, And Melting Ice: Proposal For A Coopertive Study Of The World’S Cave Ice In A Race Against Climate Change, George Veni, Lewis Land, Aurel Perşoiu
The International Workshop on Ice Caves
Climate change is a global phenomenon that is melting and threatening to melt ice deposits in many of the world’s ice caves. The National Cave and Karst Research Institute of the USA is concerned that major and important paleoclimate and paleoenvironmental records stored in cave ice will soon be lost, and is proposing an international collaborative effort to overcome funding and logistical challenges to sample and analyze at least a representative collection of ice from several regions before further melting occurs.
Climate Study In An Abandoned Auto Tunnel In Alaska, Usa, Andreas Pflitsch, David Holmgren
Climate Study In An Abandoned Auto Tunnel In Alaska, Usa, Andreas Pflitsch, David Holmgren
The International Workshop on Ice Caves
An abandoned auto tunnel in south central Alaska in an elevation of 118 m above sea level seemed to be a perfect laboratory for studying the evolution of ice speleothems in a yearly cycle. More than 1,500 ice forms like stalagmites, stalactites, columns in various shape and arrangements, developed in just 2 month to a high up to 6 meters and lasted for another 5 to 6 month. In October just the remains of the melted ice in rings and rectangular patterns of a white powder could be found. Unfortunately the mostly sealed tunnel was opened in January 2014 by …
The Monica (Monitoring Of Ice Within Caves) Project: A Multidisciplinary Approach For The Geophysical And Paleoclimatic Characterization Of Permanent Ice Deposits In The Southeastern Alps, Renato R. Colucci, Emanuele Forte, Barbara Stenni, Marco Basso Bondini, Mauro Colle Fontana, Costanza Del Gobbo, Daniele Fontana, Doriana Belligoi, Valter Maggi, Marco Filipazzi
The Monica (Monitoring Of Ice Within Caves) Project: A Multidisciplinary Approach For The Geophysical And Paleoclimatic Characterization Of Permanent Ice Deposits In The Southeastern Alps, Renato R. Colucci, Emanuele Forte, Barbara Stenni, Marco Basso Bondini, Mauro Colle Fontana, Costanza Del Gobbo, Daniele Fontana, Doriana Belligoi, Valter Maggi, Marco Filipazzi
The International Workshop on Ice Caves
On days 30 September and 1-2 October 2013, a 7.8 m long ice core has been extracted from a permanent ice cave deposit in the Southeastern Alps (Vasto’s cave, Mt.Canin - Julian Alps). Each 20 to 100 cm long section of the ice core have been immediately stored in plastic bags and preserved thanks to dry ice. The ice samples, thanks to the helicopter, has been subsequently brought on valley and promptly stored in a refrigerated van, made available by BoFrost. Thus the ice cores has been transported intact to the EUROCOLD laboratory in Milan. These operations have been carried …
Characterization Of Two Permanent Ice Cave Deposits In The Southeastern Alps (Italy) By Means Of Ground Penetrating Radar (Gpr), Renato R. Colucci, Daniele Fontana, Emanuele Forte
Characterization Of Two Permanent Ice Cave Deposits In The Southeastern Alps (Italy) By Means Of Ground Penetrating Radar (Gpr), Renato R. Colucci, Daniele Fontana, Emanuele Forte
The International Workshop on Ice Caves
In order to assess the thickness and the inner structure of some permanent ice deposits in two high elevated alpine karstic caves of the Canin massif (Alpi Giulie, Italy), we performed several multi frequency Ground Penetrating Radar (GPR) surveys. The surveys have been conducted within the project MONICA (MOnitoring of Ice within Caves), aimed at the paleoclimatic characterization of the considered cave ice deposits. GPR surveys have proved to be crucial also in finding the most suitable place for carrying out a drilling core. This has been particularly useful in the Vasto’s ice cave (VIC) in which the direct/visual estimation …
New Research In Cave Ledenica In Bukovi Vrh On Velebit Mt In Croatian Dinaric Karst, Mladen Garasic
New Research In Cave Ledenica In Bukovi Vrh On Velebit Mt In Croatian Dinaric Karst, Mladen Garasic
The International Workshop on Ice Caves
No abstract provided.
Effects Of Road Salt On Asylum Lake Geochemistry, Davina A. Wyman
Effects Of Road Salt On Asylum Lake Geochemistry, Davina A. Wyman
Masters Theses
Several studies indicate that seasonal applications of road deicers can lead to saline runoff entering surface water and groundwater, which can in turn change the chemistry, density, and physical mixing patterns of urban lakes. An investigation at Asylum Lake, an urban lake located near three major roadways, was conducted to determine the degree of road salt contamination in the lake, to determine if salt loading disrupts seasonal mixing patterns, and to determine the extent of redox stratification present due to eutrophic conditions. Samples were collected monthly from the deepest point in Asylum Lake over a 19-month period and analyzed for …
Seismic Imaging Of Mantle Transition Zone Discontinuities Beneath The Northern Red Sea And Adjacent Areas, A. A. Mohamed, Stephen S. Gao, A. A. Elsheikh, Kelly H. Liu, Youqiang Yu, R. E. Fat-Helbary
Seismic Imaging Of Mantle Transition Zone Discontinuities Beneath The Northern Red Sea And Adjacent Areas, A. A. Mohamed, Stephen S. Gao, A. A. Elsheikh, Kelly H. Liu, Youqiang Yu, R. E. Fat-Helbary
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The dramatic asymmetry in terms of surface elevation, Cenozoic volcanisms and earthquake activity across the Red Sea is an enigmatic issue in global tectonics, partially due to the unavailability of broad-band seismic data on the African Plate adjacent to the Red Sea. Here, we report the first comprehensive image of the mantle transition zone (MTZ) discontinuities using data from the Egyptian National Seismic Network, and compare the resulting depths of the 410 and 660-km discontinuities with those observed on the Arabian side. Our results show that when a standard earth model is used for time-to-depth conversion, the resulting depth of …
Mantle Transition Zone Discontinuities Beneath The Contiguous United States, Stephen S. Gao, Kelly H. Liu
Mantle Transition Zone Discontinuities Beneath The Contiguous United States, Stephen S. Gao, Kelly H. Liu
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Using over 310,000 high-quality radial receiver functions recorded by the USArray and other seismic stations in the contiguous United States, the depths of the 410 km and 660 km discontinuities (d410 and d660) are mapped in over 1,000 consecutive overlapping circles with a radius of 1⁰. The average mantle transition zone (MTZ) thickness for both the western and central/eastern U.S. is within 3 km from the global average of 250 km, suggesting an overall normal MTZ temperature beneath both areas. The Pacific Coast Ranges and the southern Basin and Range Province are underlain by a depressed d410, indicating higher-than-normal temperature …
The Significance Of Dolomitized Hunton Strata In The Kinta And Bonanza Fields Of The Arkoma Basin, Christopher William Trotter
The Significance Of Dolomitized Hunton Strata In The Kinta And Bonanza Fields Of The Arkoma Basin, Christopher William Trotter
Graduate Theses and Dissertations
The Hunton Group has been a prolific hydrocarbon-producing reservoir across much of Oklahoma and western Arkansas. The group is a Silurian-Devonian aged interval that is comprised of sequences of limestone, dolomite, and calcareous shale. The group is divided into several formations. The subdivisions include the Chimneyhill Subgroup, Henryhouse, Haragan and Bois d'Arc Formations. Reservoir quality in the Hunton Group is significantly dependent upon the diagenetic events and depositional environments of the sediments. Most hydrocarbon production, from within the Hunton Group, comes from members that have undergone dolomite replacement of the parent limestone.
The higher amounts of porosity and permeability are …
Comparisons Of Hydrogeologic Modeling Methods To Define Capture Zones For Public Water Supply Wells In Northern Arkansas, Paula Anderson
Comparisons Of Hydrogeologic Modeling Methods To Define Capture Zones For Public Water Supply Wells In Northern Arkansas, Paula Anderson
Graduate Theses and Dissertations
The usefulness, applicability, and practicality of more complex and resource consuming methods for groundwater modeling has been in question since computer based groundwater modeling was established (Anderson, 1992). In many situations, computer modeling of groundwater flow is a necessity and useful for extrapolating data where none exists or it is impossible or impractical to acquire. However, when delineating a recharge area around a public water well for protection purposes, it is unknown if more detailed computer modeling results are better than simpler hydrologic calculations and site study. In the case of public drinking water supply wells located in various aquifers …
Mars-Relevant Phosphate Minerals And Implications For Martian Habitability, Christopher Adcock
Mars-Relevant Phosphate Minerals And Implications For Martian Habitability, Christopher Adcock
UNLV Theses, Dissertations, Professional Papers, and Capstones
This dissertation is comprised of three studies focused on martian phosphate availability, with an introductory chapter introducing and linking the three studies. Chapter two is on the subject of merrillite synthesis. Merrillite is an extraterrestrial Ca-phosphate mineral similar to the mineral whitlockite and is found as a dominant primary phosphate mineral in martian meteorites. The chapter includes methods of whitlockite and merrillite synthesis as well as a detailed characterization of the produced minerals and a mechanism by which charge balance can be maintained when merrillite is synthesized through dehydrogenation of whitlockite.
Chapter three presents the results of kinetic and thermodynamic …
Porphyry Copper Exploration Of The Hualapai Mountains, Mohave County, Arizona, Usa: A Multi-Faceted Approach, Patrick Kevin Meazell
Porphyry Copper Exploration Of The Hualapai Mountains, Mohave County, Arizona, Usa: A Multi-Faceted Approach, Patrick Kevin Meazell
UNLV Theses, Dissertations, Professional Papers, and Capstones
A variety of exploration methods including geologic mapping, trace- and major-level geochemical analyses, fluid inclusion petrography, remote sensing, and SWIR clay spectroscopy were used to investigate the potential for porphyry Cu-Mo mineralization at the Wikieup prospect, in the southern Hualapai Mountains of northwestern Arizona. Aspects of the Mineral Park mine were used as an analogue to guide exploration due to the proximity and similar geology of the area.
The Hualapai Mountains are a series of northwest-trending Precambrian gneisses, schists, granitoids and amphibolites that have been cut by younger intrusive rocks. Within the Wikieup study area, the intrusive rocks include aplite …
Kinematics And Timing Of Superposed Deformation In The Funeral Mountains Metamorphic Core Complex, Death Valley, Ca, Katrina Marie Sauer
Kinematics And Timing Of Superposed Deformation In The Funeral Mountains Metamorphic Core Complex, Death Valley, Ca, Katrina Marie Sauer
UNLV Theses, Dissertations, Professional Papers, and Capstones
The Funeral Mountains metamorphic core complex (FMMCC) in Death Valley, California exposes middle to lower crustal rocks of the Sevier-Laramide orogen in the footwall of the Miocene Boundary Canyon detachment. The structurally deepest rocks in the FMMCC are exposed in Monarch Canyon, where the Meso- to Neoproterozoic metasedimentary rocks record upper amphibolite facies metamorphism with migmatites developed at the deepest levels. Distributed ductile deformation and stratigraphically-localized high-strain zones, termed intracore shear zones, are responsible for attenuation and local stratigraphic omission during top-northwest non-coaxial deformation. The structurally deepest Monarch Spring shear zone (MSSZ) juxtaposes the migmatitic paragneisses below against greenschist to …
Build-And-Fill Development Of Lower Ismay (Middle Pennsylvanian Paradox Formation) Phylloid-Algal Mounds Of The Paradox Basin, Southeastern Utah, Lincoln H. Reed
Build-And-Fill Development Of Lower Ismay (Middle Pennsylvanian Paradox Formation) Phylloid-Algal Mounds Of The Paradox Basin, Southeastern Utah, Lincoln H. Reed
Theses and Dissertations
Phylloid-algal mounds form heterogeneous hydrocarbon reservoirs in the southeastern portion (Blanding sub-basin) of the Paradox Basin. Well-studied Lower Ismay mounds exposed along walls of the San Juan River gorge in the vicinity of Eight Foot Rapids, the west limb of the Raplee Anticline, and at the classic Honaker Trail locality (southwestern Paradox Basin) have often been cited as outcrop analogs of productive subsurface mounds. Until now, however, there has not been a complete description of the distribution, size, and spacing of outcropping algal mounds at the classic Eight Foot Rapids locality. The Lower Ismay sequence was analyzed in the context …
Integrating Land Cover Modeling And Adaptive Management To Conserve Endangered Species And Reduce Catastrophic Fire Risk, David Breininger, Brean Duncan, Mitchell Eaton, Fred Johnson, James Nichols
Integrating Land Cover Modeling And Adaptive Management To Conserve Endangered Species And Reduce Catastrophic Fire Risk, David Breininger, Brean Duncan, Mitchell Eaton, Fred Johnson, James Nichols
United States Geological Survey: Staff Publications
Land cover modeling is used to inform land management, but most often via a two-step process, where science informs how management alternatives can influence resources, and then, decision makers can use this information to make decisions. A more efficient process is to directly integrate science and decision-making, where science allows us to learn in order to better accomplish management objectives and is developed to address specific decisions. Co-development of management and science is especially productive when decisions are complicated by multiple objectives and impeded by uncertainty. Multiple objectives can be met by the specification of trade offs, and relevant uncertainty …
Characterization Of The Depositional Environment Of Phreatic Overgrowths On Speleothems In The Littoral Caves Of Mallorca (Spain): A Physical, Geochemical, And Stable Isotopic Study, Liana Marie Boop
USF Tampa Graduate Theses and Dissertations
Phreatic overgrowths on speleothems (POS) are one of many sea-level proxies available to Quaternary geologists in Mallorca; these carbonate encrustations form at the air-water interface in cave passages flooded with brackish water. POS are ideal for reconstruction of western Mediterranean sea level because they are widespread in Mallorca's caves, can be precisely dated by U-series methods, constrain sea-level stands to sub-meter elevation, and are well preserved and accessible in the subterranean environment.
This research investigates the POS depositional environment, which is relatively understudied compared to the other proxies used for sea-level reconstructions. This disparity has led to assumptions on many …
Timing Of Svalbard/Barents Sea Ice Sheet Decay During The Last Glacial Termination, Tasha Snow
Timing Of Svalbard/Barents Sea Ice Sheet Decay During The Last Glacial Termination, Tasha Snow
USF Tampa Graduate Theses and Dissertations
The Arctic and North Atlantic underwent significant climactic changes since the Last Glacial Maximum (25,000 years before present (1950 AD); ka BP), but offsets in the timing of events between the two regions are poorly constrained due to age model uncertainties that arise from changing radiocarbon reservoir ages. Here, we use a relatively high-resolution, multi-proxy stable isotope and sedimentologic dataset from Eastern Fram Strait (ODP Leg 162 Site 986) marine sediments to constrain the timing of Svalbard/Barents Sea Ice Sheet decay and infer deglacial reservoir ages over the last 30 ka. We use magnetic susceptibility, inorganic and organic carbon, foraminiferal …
Geochemistry And Stable Isotopes Of Surface Water And Groundwater In The Continental Pit In Butte, Montana, Usa, Amber Mcgivern
Geochemistry And Stable Isotopes Of Surface Water And Groundwater In The Continental Pit In Butte, Montana, Usa, Amber Mcgivern
Graduate Theses & Non-Theses
The Continental porphyry Cu‐Mo mine, located 2 km east of the famous Berkeley Pit lake of Butte, Montana, contains two small lakes that vary in size depending on mining activity. In contrast to the acidic Berkeley Pit lake, the Continental Pit waters have near-neutral pH and relatively low metal concentrations. The main reason is geological: whereas the Berkeley Pit mined highly‐altered granite rich in pyrite with no neutralizing potential, the Continental Pit is mining weakly‐altered granite with lower pyrite concentrations and up to 1‐2% hydrothermal calcite. The purpose of this study was to gather and interpret information that bears on …
Mechanistic Models Of Biofilm Growth In Porous Media, Priyank Jaiswal, K. Fathiya Al-Hadrami, Estella A. Atekwana, Eliot A. Atekwana
Mechanistic Models Of Biofilm Growth In Porous Media, Priyank Jaiswal, K. Fathiya Al-Hadrami, Estella A. Atekwana, Eliot A. Atekwana
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Nondestructive acoustics methods can be used to monitor in situ biofilm growth in porous media. In practice, however, acoustic methods remain underutilized due to the lack of models that can translate acoustic data into rock properties in the context of biofilm. In this paper we present mechanistic models of biofilm growth in porous media. The models are used to quantitatively interpret arrival times and amplitudes recorded in the 29 day long Davis et al. (2010) physical scale biostimulation experiment in terms of biofilm morphologies and saturation. The model pivots on addressing the sediment elastic behavior using the lower Hashin-Shtrikman bounds …
Effective Geoscience Pedagogy At The Undergraduate Level, Kelsey Warden
Effective Geoscience Pedagogy At The Undergraduate Level, Kelsey Warden
Open Access Theses
This investigation used constructivist pedagogical methods within the framework of an introductory level undergraduate geoscience course to gauge both the changes in attitude and cognition of students. Pedagogy was modified in the laboratory setting, but maintained in the lecture setting and homework. Curriculum was also maintained in the lecture, but was changed in the laboratory to emphasize the large concepts and systems stressed in Earth Science Literacy Principles. Student understanding of these concepts and systems was strengthened by factual knowledge, but recall and memorization were not the goal of the laboratory instruction. The overall goal of the study was to …
Paterae On Io: Geologic Mapping Of Tupan Patera And Experimental Models, Megan Carolee Decker
Paterae On Io: Geologic Mapping Of Tupan Patera And Experimental Models, Megan Carolee Decker
Theses and Dissertations
Paterae cover approximately 2% of the surface of Io, Jupiter’s volcanically active moon. To understand the formation of these volcano-tectonic depressions we created a geologic map of a key region and compared this map with experimental models for Io paterae. Our mapping region is Tupan Patera, a patera that has experienced recent activity and is a detected hot spot. We identified four primary types of geologic materials: plains, patera floors, flows, and diffuse deposits. We constructed an experimental model to test previous suggestions that paterae may form as volatiles in the silicate crust are vaporized by rising magma, creating instability, …
Tectonics Of Saturn's Moon Titan And Tsunami Modeling Of The 1629 Mega-Thrust Earthquake In Eastern Indonesia, Yung-Chun Liu
Tectonics Of Saturn's Moon Titan And Tsunami Modeling Of The 1629 Mega-Thrust Earthquake In Eastern Indonesia, Yung-Chun Liu
Theses and Dissertations
Chapter 1-2:The Cassini RADAR mapper has imaged elevated blocks and mountains on Titan we term ‘ridges’. Two unresolved problems regarding Titan's surface are still debated: what is the origin of its ridges and was there tectonic activity on Titan? To understand the processes that produced the ridges, in this study, (1) we analyze the distribution and orientation of ridges through systematic geomorphologic mapping and (2) we compare the location of the ridges to a new global topographic map to explore the correlation between elevation and ridges and the implications for Titan's surface evolution. Globally, the orientation of ridges is nearly …
A Multi-Proxy Approach To Understanding Abrupt Climate Change And Laurentide Ice Sheet Melting History Based On Gulf Of Mexico Sediments, Clare Carlisle Williams
A Multi-Proxy Approach To Understanding Abrupt Climate Change And Laurentide Ice Sheet Melting History Based On Gulf Of Mexico Sediments, Clare Carlisle Williams
USF Tampa Graduate Theses and Dissertations
During the last deglaciation (ca. 24-10 ka thousand years ago (ka)), the North American Laurentide Ice Sheet (LIS) was a major source of meltwater to the Arctic Ocean, North Atlantic Ocean, and the Gulf of Mexico (GOM), and it is hypothesized that meltwater routing played an important role in regulating Late Quaternary millennial-scale climate variability, via its influence on Atlantic Meridional Overturning Circulation (AMOC). For example, the meltwater routing hypothesis predicts that a rerouting of meltwater from the GOM to the North Atlantic and/or Arctic Oceans resulted in a decrease of North Atlantic Deep Water (NADW) formation and subsequent cooling …
Rapid Reservoir Erosion, Hyperconcentrated Flow, And Downstream Deposition Triggered By Breaching Of 38 M Tall Condit Dam, White Salmon River, Washington, Andrew C. Wilcox, Jim E. O'Connor, Jon J. Major
Rapid Reservoir Erosion, Hyperconcentrated Flow, And Downstream Deposition Triggered By Breaching Of 38 M Tall Condit Dam, White Salmon River, Washington, Andrew C. Wilcox, Jim E. O'Connor, Jon J. Major
Geosciences Faculty Publications
Condit Dam on the White Salmon River,Washington, a 38m high dam impounding a large volume (1.8 million m3) of fine-grained sediment (60% sand, 35% silt and clay, and 5% gravel), was rapidly breached in October 2011. This unique dam decommissioning produced dramatic upstream and downstream geomorphic responses in the hours and weeks following breaching. Blasting a 5 m wide hole into the base of the dam resulted in rapid reservoir drawdown, abruptly releasing ~1.6 million m3 of reservoir water, exposing reservoir sediment to erosion, and triggering mass failures of the thickly accumulated reservoir sediment. Within 90 min …
Evolution And Equilibration Of Artificial Morphologic Perturbations In The Form Of Nearshore Berm Nourishments Along The Florida Gulf Coast, Katherine Emily Brutsché
Evolution And Equilibration Of Artificial Morphologic Perturbations In The Form Of Nearshore Berm Nourishments Along The Florida Gulf Coast, Katherine Emily Brutsché
USF Tampa Graduate Theses and Dissertations
Inlets and channels are dredged often to maintain navigation safety. It is beneficial to reintroduce the dredged material back into the littoral system, in the form of beach or nearshore nourishments. Nourishment in the nearshore is becoming an increasingly utilized method, particularly for dredged material that contains more fine sediment than the native beach. This research examines the morphologic evolution of two different nearshore nourishments. A nearshore berm was constructed at Fort Myers Beach, Florida using mixed-sized sediment dredged from a nearby channel. The nearshore berm was placed in water depths between 1.2 and 2.4 m with the berm crest …
Wetlands On The Thousand Lake Mountain Mega-Landslide As Paleoclimate Proxies, Ryan Andros Shurtliff
Wetlands On The Thousand Lake Mountain Mega-Landslide As Paleoclimate Proxies, Ryan Andros Shurtliff
Theses and Dissertations
The Windy Ridge mega-landslide in Wayne and Sevier Counties originated in Lates tPleistocene time as established by 14C ages on basal organic-rich clay and peat sediment from bogs that developed on the slide. The contact depth between bog and landslide was estimated using high-resolution seismic reflection to find the thickest sediment. Four bogs were cored at their depocenters, and organic material at the slide contact was used for age determinations. The oldest bog sediments ages are 10,600 ± 46, 10,556 ± 34, 12,511 ± 134, and 12,886 ± 91 calibrated years BP. Ages represent two sliding events. First, at the …
Dendrochronological Analysis Of The Austin House
Dendrochronological Analysis Of The Austin House
Historic Structures
Dating historical structures using dendrochronology. The Historical Structures collection consists of reports that are the result of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: McGrath, Sarah; Reinthal, Mary; Starr, Kaitlin; Wiesenberg, Nicholas; Wiles, Greg
Sand Sea Extents And Sediment Volumes On Titan From Dune Parameters, Karl D. Arnold
Sand Sea Extents And Sediment Volumes On Titan From Dune Parameters, Karl D. Arnold
Theses and Dissertations
Linear dunes are one of the most abundant and important features on the surface of Titan. We present a model for estimating the volume of dune sediment using the area coverage of Titan's sand seas along with dune widths, spacings, and heights. This helps to reveal local sediment transport and deposition. We refine global dune area estimates from Cassini SAR (Synthetic Aperture RADAR) of 20 million km2 or 24 ± 3% of Titan's surface based on ~50% Cassini RADAR global coverage. Additionally, the global area of sand seas is estimated from a joint analysis of Cassini SAR and ISS (Imaging …