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Articles 1 - 26 of 26
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8000 Years Of Environmental Evolution Of Barrier–Lagoon Systems Emplaced In Coastal Embayments (Nw Iberia), Rita González-Villanueva, Marta Pérez-Arlucea, Susana Costas, Roberto Bao, Xose L. Otero, Ronald J. Goble
8000 Years Of Environmental Evolution Of Barrier–Lagoon Systems Emplaced In Coastal Embayments (Nw Iberia), Rita González-Villanueva, Marta Pérez-Arlucea, Susana Costas, Roberto Bao, Xose L. Otero, Ronald J. Goble
Department of Earth and Atmospheric Sciences: Faculty Publications
The rocky and indented coast of NW Iberia is characterized by the presence of highly valuable and vulnerable, small and shallow barrier– lagoon systems structurally controlled. The case study was selected to analyse barrier–lagoon evolution based on detailed sedimentary architecture, chronology, geochemical and biological proxies. The main objective is to test the hypothesis of structural control and the significance at regional scale of any highenergy event recorded. This work is also aimed at identifying general patterns and conceptualizing the formation and evolution of this type of coastal systems. The results allowed us to establish a conceptual model of Holocene evolution …
Integration And Delivery Of Interferometric Synthetic Aperture Radar [Insar] Data Into Stormwater Planning Within Karst Terranes, Brian Bruckno, Andrea Vaccari, Edward Hoppe, Scott Acton, Elizabeth Campbell
Integration And Delivery Of Interferometric Synthetic Aperture Radar [Insar] Data Into Stormwater Planning Within Karst Terranes, Brian Bruckno, Andrea Vaccari, Edward Hoppe, Scott Acton, Elizabeth Campbell
Department of Earth and Atmospheric Sciences: Faculty Publications
As part of two USDOT-funded studies focused on the development of satellite-based Interferometric Synthetic Aperture Radar (InSAR) technology, the researchers integrated InSAR-derived point cloud data into the transportation design process to optimize the location of a stormwater management system in a karst terrane. After initial validation, the InSAR data (over 1.67 million data points comprising various “scatterers”) were brought into a GIS dataframe and georeferenced to locations of known sinkholes. This dataset was then used to evaluate karst hazard within a 40x40km data frame located in the Valley and Ridge Province of Virginia. The group identified systematic kinematic differences in …
A New Taeniolabidoid Multituberculate (Mammalia) From The Middle Puercan Of The Nacimiento Formation, New Mexico, And A Revision Of Taeniolabidoid Systematics And Phylogeny, Thomas E. Williamson, Stephen L. Brusatte, Ross Secord, Sarah Shelley
A New Taeniolabidoid Multituberculate (Mammalia) From The Middle Puercan Of The Nacimiento Formation, New Mexico, And A Revision Of Taeniolabidoid Systematics And Phylogeny, Thomas E. Williamson, Stephen L. Brusatte, Ross Secord, Sarah Shelley
Department of Earth and Atmospheric Sciences: Faculty Publications
Multituberculates were amongst the most abundant and taxonomically diverse mammals of the late Mesozoic and the Paleocene, reaching their zenith in diversity and body size in the Paleocene. Taeniolabidoidea, the topic of this paper, includes the largest known multituberculates, which possess highly complex cheek teeth adapted for herbivory. A new specimen from the early Paleocene (middle Puercan; biochron Pu2) of the Nacimiento Formation, New Mexico represents a new large-bodied taeniolabidoid genus and species, Kimbetopsalis simmonsae. A phylogenetic analysis to examine the relationships within Taeniolabidoidea that includes new information from Kimbetopsalis gen. et sp. nov. and gen. nov. and …
Aulacoseira Stevensiae Sp. Nov. (Coscinodiscophyceae, Bacillariophyta), A New Diatom From Ho Ba Bê, Bac Kan Province, Northern Viêt Nam, D. Marie Weide
Aulacoseira Stevensiae Sp. Nov. (Coscinodiscophyceae, Bacillariophyta), A New Diatom From Ho Ba Bê, Bac Kan Province, Northern Viêt Nam, D. Marie Weide
Department of Earth and Atmospheric Sciences: Faculty Publications
A new species of Aulacoseira Thwaites is described from piston core samples from Ho Ba Bê in the karst region of northern Viêt Nam. Although it closely resembles Aulacoaseira subborealis (Nygaard) Denys, Muylaert & Krammer, A. stevensiae Weide sp. nov. is designated a new species based mainly on morphological differences in the spines, including invariably inclined spines that are rounded, differences in the Ringleiste, areola pattern and overall size. Aulacoseira stevensiae is present throughout a core that spans the last 500 years. It was a major component of the diatom community, but the populations have recently decreased, possibly being outcompeted …
Post-Mississippian Tectonic Evolution Of The Nemaha Tectonic Zone And Midcontinent Rift System, Se Nebraska And N Kansas, Caroline M. Burberry, R. Matthew Joeckel, Jesse T. Korus
Post-Mississippian Tectonic Evolution Of The Nemaha Tectonic Zone And Midcontinent Rift System, Se Nebraska And N Kansas, Caroline M. Burberry, R. Matthew Joeckel, Jesse T. Korus
Department of Earth and Atmospheric Sciences: Faculty Publications
The geologic structures of the central Midcontinent of the USA are largely buried and known only from geophysical datasets, coupled with sparse well control and limited outcrop. Such unconstrained geophysical models preclude a deeper assessment of possible continental interior seismic hazards, which have the potential to cause appreciable damage. Within the study area in southeastern Nebraska and northeastern Kansas is an area of elevated seismic risk, with a spatial relationship to the Nemaha Tectonic Zone and the Midcontinent Rift System. Using sequential restorations of three published cross sections within Nebraska and Kansas this study demonstrates that the Nemaha Tectonic Zone …
Hydroclimatic Shifts In Northeast Thailand During The Last Two Millennia — The Record Of Lake Pa Kho, Sakonvan Chawchai, Akkaneewut Chabangborn, Sherilyn C. Fritz, Minna Väliranta, Carl-Magnus Mörth, Maarten Blaauw, Paul J. Reimer, Paul J. Kusic, Ludvig Löwemark, Barbara Wohlfarth
Hydroclimatic Shifts In Northeast Thailand During The Last Two Millennia — The Record Of Lake Pa Kho, Sakonvan Chawchai, Akkaneewut Chabangborn, Sherilyn C. Fritz, Minna Väliranta, Carl-Magnus Mörth, Maarten Blaauw, Paul J. Reimer, Paul J. Kusic, Ludvig Löwemark, Barbara Wohlfarth
Department of Earth and Atmospheric Sciences: Faculty Publications
The Southeast Asian mainland is located in the central path of the Asian summer monsoon, a region where paleoclimatic data are still sparse. Here we present a multi-proxy (TOC, C/N, δ13C, biogenic silica, and XRF elemental data) study of a 1.5 m sediment/peat sequence from Lake Pa Kho, northeast Thailand, which is supported by 20 AMS 14C ages. Hydroclimatic reconstructions for Pa Kho suggest a strengthened summer monsoon between BC 170–AD 370, AD 800–960, and after AD 1450; and a weakening of the summer monsoon between AD 370–800, and AD 1300–1450. Increased run-off and a higher nutrient supply after AD …
The Effect Of Basement Fault Reactivation On The Triassic—Recent Geology Of Kurdistan, North Iraq, Caroline M. Burberry
The Effect Of Basement Fault Reactivation On The Triassic—Recent Geology Of Kurdistan, North Iraq, Caroline M. Burberry
Department of Earth and Atmospheric Sciences: Faculty Publications
The Zagros orogenic belt is underlain by a complex faulted Precambrian basement. Major fault trends originating in this basement have been invoked to explain large-scale structural changes along the strike of the orogen, e.g. the development of the Kirkuk Embayment (Kurdistan, Iraq) and the Lurestan Salient (Iran). However, within the Kirkuk Embayment, these structural trends have not previously been considered as an interacting group of faults which are periodically reactivated. This contribution first presents a revised basement fault map for the Kirkuk Embayment, created from interpreted gravity data, existing fault maps and remote sensing lineament analyses. This map is then …
Temporal And Spatial Variability In Dune Reactivation Across The Nebraska Sand Hills, Usa, Rebecca L. Schmeisser Mckean, Ronald J. Goble, Joseph B. Mason, James Swinehart, David B. Loope
Temporal And Spatial Variability In Dune Reactivation Across The Nebraska Sand Hills, Usa, Rebecca L. Schmeisser Mckean, Ronald J. Goble, Joseph B. Mason, James Swinehart, David B. Loope
Department of Earth and Atmospheric Sciences: Faculty Publications
The Nebraska Sand Hills is a stabilized dune field on the Great Plains of North America. Although it is well known that this dune field, like several others on the Great Plains, last experienced widespread activity during the Medieval Climatic Anomaly (MCA, ~AD 900–1300), spatial variation in the timing and nature of drought development is poorly constrained. To elucidate spatial trends in dune reactivation, samples potentially representing MCA activity across the Sand Hills were collected and dated using optically stimulated luminescence (OSL). Ages from the older part of the MCA were obtained from eolian sediments in the northwestern Sand Hills, …
Patterns Of Terrestrial And Limnologic Development In The Northern Greater Yellowstone Ecosystem (Usa) During The Late-Glacial/Early-Holocene Transition, Teresa R. Krause, Yanbin Lu, Cathy Whitlock, Sherilyn C. Fritz, Kenneth L. Pierce
Patterns Of Terrestrial And Limnologic Development In The Northern Greater Yellowstone Ecosystem (Usa) During The Late-Glacial/Early-Holocene Transition, Teresa R. Krause, Yanbin Lu, Cathy Whitlock, Sherilyn C. Fritz, Kenneth L. Pierce
Department of Earth and Atmospheric Sciences: Faculty Publications
A high-resolution record of pollen, charcoal, diatom, and lithologic data from Dailey Lake in south-western Montana describes postglacial terrestrial and limnologic development from ice retreat ca. 16,000 cal yr BP through the early Holocene. Following deglaciation, the landscape surrounding Dailey Lake was sparsely vegetated, and erosional input into the lake was high. As summer insolation increased and ice recessional processes subsided, Picea parkland developed and diatoms established in the lake at 13,300 cal yr BP. Closed subalpine forests of Picea, Abies, and Pinus established at 12,300 cal yr BP followed by the development of open Pinus and Pseudotsuga forests at …
A Fast Visible Infrared Imaging Radiometer Suite Simulator For Cloudy Atmospheres, Chao Liu, Ping Yang, Shaima L. Nasiri, Steven Platnick, Kerry G. Meyer, Chenxi Wang, Shouguo Ding
A Fast Visible Infrared Imaging Radiometer Suite Simulator For Cloudy Atmospheres, Chao Liu, Ping Yang, Shaima L. Nasiri, Steven Platnick, Kerry G. Meyer, Chenxi Wang, Shouguo Ding
Department of Earth and Atmospheric Sciences: Faculty Publications
A fast instrument simulator is developed to simulate the observations made in cloudy atmospheres by the Visible Infrared Imaging Radiometer Suite (VIIRS). The correlated k distribution technique is used to compute the transmissivities associated with absorbing atmospheric gases. The bulk scattering properties of ice clouds are based on the ice model used for the Moderate Resolution Imaging Spectroradiometer Collection 6 ice cloud products, and those of water clouds are computed with the Lorenz-Mie theory. Two fast radiative transfer models based on precomputed ice cloud look-up tables are used for the VIIRS solar and infrared channels. The accuracy and efficiency of …
Diatoms At >5000 Meters In The Quelccaya Summit Dome Glacier, Peru, Sherilyn C. Fritz, Bruce E. Brinson, W. E. Billups, Lonnie G. Thompson
Diatoms At >5000 Meters In The Quelccaya Summit Dome Glacier, Peru, Sherilyn C. Fritz, Bruce E. Brinson, W. E. Billups, Lonnie G. Thompson
Department of Earth and Atmospheric Sciences: Faculty Publications
Diatoms were found in late Holocene age ice-core samples recovered from the Quelccaya Summit Dome in the tropical Andes of Peru and were imaged by environmental scanning electron microscopy and identified. Freshwater diatoms in the genera Hantzschia, Pinnularia, and Aulacoseira were the most common taxa in the samples and indicate a freshwater source for the material, which also is suggested by the presence of the freshwater alga Volvox. The overall species composition of the diatoms suggests that the majority of taxa originated from a high-elevation lake or wetland in the cordillera surrounding the ice cap. The abundant …
The Footprints Of Ancient Co2-Driven Flow Systems: Ferrous Carbonate Concretions Below Bleached Sandstone, David B. Loope, Richard M. Kettler
The Footprints Of Ancient Co2-Driven Flow Systems: Ferrous Carbonate Concretions Below Bleached Sandstone, David B. Loope, Richard M. Kettler
Department of Earth and Atmospheric Sciences: Faculty Publications
Iron-rich carbonates and the oxidized remains of former carbonates (iron-oxide concretions) underlie bleached Navajo Sandstone over large portions of southern Utah. Iron in the carbonates came from hematite rims on sand grains in the upper Navajo that were dissolved when small quantities of methane accumulated beneath the sealing Carmel Formation. As a second buoyant gas (CO2 derived from Oligocene–Miocene magmas) reached the seal and migrated up dip, it dissolved in the underlying water, enhancing the solution’s density. This water carried the released ferrous iron and the methane downward. Carbonates precipitated when the descending, reducing water degassed along fractures. The …
First Report On Dinosaur Tracks From The Burro Can Yon Formation, San Juan County, Utah, Usa – Evidence Of A Diverse, Hitherto Un Known Lower Cretaceous Dinosaur Fauna, Jesper Milan, Luis M. Chiappe, David B. Loope, James I. Kirkland, Martin G. Lockley
First Report On Dinosaur Tracks From The Burro Can Yon Formation, San Juan County, Utah, Usa – Evidence Of A Diverse, Hitherto Un Known Lower Cretaceous Dinosaur Fauna, Jesper Milan, Luis M. Chiappe, David B. Loope, James I. Kirkland, Martin G. Lockley
Department of Earth and Atmospheric Sciences: Faculty Publications
The newly discovered White Mesa tracksite in the Burro Canyon Formation represents a snap shot of a diverse, Lower Cretaceous dinosaur fauna from south-eastern Utah. The tracks were found at a construction site where the sand stone had been bull dozed and broken up. All tracks were found as deep, well-preserved natural casts on the under side of the sand stone slabs. Individual theropod tracks are 19–57 cm in length; one peculiar track shows evidence of a possible pathological swelling in the middle of digit III and an apparently didactyl track is tentatively as signed to a dromaeosaurid. Individual sauropod …
Life And Liesegang: Outcrop-Scale Microbially Induced Diagenetic Structures And Geochemical Self-Organization Phenomena Produced By Oxidation Of Reduced Iron, Richard M. Kettler, David B. Loope, Karrie A. Weber, Paul B. Niles
Life And Liesegang: Outcrop-Scale Microbially Induced Diagenetic Structures And Geochemical Self-Organization Phenomena Produced By Oxidation Of Reduced Iron, Richard M. Kettler, David B. Loope, Karrie A. Weber, Paul B. Niles
Department of Earth and Atmospheric Sciences: Faculty Publications
The Kanab Wonderstone is sandstone (Shinarump Member, Chinle Formation) that is cemented and stained with iron oxide. The iron-oxide cementation and staining in these rocks have been considered examples of the Liesegang phenomenon, but we will show that they comprise a microbially induced structure. The spacing of bands of iron-oxide stain follow the Jablczynski spacing law (wherein the spacing between bands of iron-oxide stain increases as one traverses a series of bands) characteristic of Liesegang. Bands of iron-oxide cement exhibit more variable spacing and exhibit a weak but significant correlation between band thickness and distance between bands of cement. The …
Effect Of Cold Wave On Winter Visibility Over Eastern China, Wenjun Qu, Jun Wang, Xiaoye Zhang, Zhifeng Yang, Shanhong Gao
Effect Of Cold Wave On Winter Visibility Over Eastern China, Wenjun Qu, Jun Wang, Xiaoye Zhang, Zhifeng Yang, Shanhong Gao
Department of Earth and Atmospheric Sciences: Faculty Publications
Considerable concern has been raised on the severe wintertime haze episodes over eastern China (ECN) where visibility (Vis) decline in winter is identified from 1973 to 2012 (-0.68 km per 10 years or -26% in 40 years). Based upon the analysis of daily Vis and weather records, cold wave (CW) originating from high latitudes is found to increase Vis by 2.7 km on average because of its relatively stronger wind and drier, cleaner air mass compared with the typical, stable midlatitude air over ECN in winter. However, the lessening frequency of CW occurrence and cold air activity in recent years …
A Fast Visible Infrared Imaging Radiometer Suite Simulator For Cloudy Atmospheres, Chao Liu, Ping Yang, Steven Platnick, Kerry G. Meyer, Chenxi Wang, Shouguo Ding
A Fast Visible Infrared Imaging Radiometer Suite Simulator For Cloudy Atmospheres, Chao Liu, Ping Yang, Steven Platnick, Kerry G. Meyer, Chenxi Wang, Shouguo Ding
Department of Earth and Atmospheric Sciences: Faculty Publications
A fast instrument simulator is developed to simulate the observations made in cloudy atmospheres by the Visible Infrared Imaging Radiometer Suite (VIIRS). The correlated k distribution technique is used to compute the transmissivities associated with absorbing atmospheric gases. The bulk scattering properties of ice clouds are based on the ice model used for the Moderate Resolution Imaging Spectroradiometer Collection 6 ice cloud products, and those ofwater clouds are computedwith the Lorenz-Mie theory. Two fast radiative transfer models based on precomputed ice cloud look-up tables are used for the VIIRS solar and infrared channels. The accuracy and efficiency of the fast …
4-D Evolution Of Anticlines And Implications For Hydrocarbon Exploration Within The Zagros Fold-Thrust Belt, Kurdistan Region, Iraq, Mjahid M. Zebari, Caroline M. Burberry
4-D Evolution Of Anticlines And Implications For Hydrocarbon Exploration Within The Zagros Fold-Thrust Belt, Kurdistan Region, Iraq, Mjahid M. Zebari, Caroline M. Burberry
Department of Earth and Atmospheric Sciences: Faculty Publications
The Zagros Fold-Thrust Belt, extending from southern Iran, through northern Iraq and into Turkey, is characterized by elongate NW-trending anticlines that house large hydrocarbon accumulations. In recent years, the Kurdistan region of northern Iraq has become an area of interest for both structural studies and petroleum exploration-related investigation. Key questions to be answered concern the nature of the anticlines and whether the geometry of any associated thrusts can be predicted from surface geomorphology, as well the 4-D evolution of the area and along-strike continuity of the anticlines. To address these questions, this study combines field data, remote-sensing data concerning the …
Spatial And Temporal Variation In Penetrative Strain During Compression: Insights From Analog Models, Caroline M. Burberry
Spatial And Temporal Variation In Penetrative Strain During Compression: Insights From Analog Models, Caroline M. Burberry
Department of Earth and Atmospheric Sciences: Faculty Publications
Penetrative strain constitutes the proportion of the total shortening across an orogen that is not accommodated by the development of macroscale structures such as folds and thrusts. The accommodation of shortening by penetrative strain is widely considered to be an important process during compression, but variation in the distribution of penetrative strain during a deformation sequence is not well understood. This study provides some first-order constraints on magnitude, timing, and distribution of penetrative strain during deformation. Eight simple models, each with a geometrically and mechanically similar starting configuration, within the limits of sandbox models, were shortened to different amounts. Model …
Integrating Geoscience Into Undergraduate Education About Environment, Society, And Sustainability Using Place-Based Learning: Three Examples, David Gosselin, Steven Burian, Tim Lutz, Julie Maxson
Integrating Geoscience Into Undergraduate Education About Environment, Society, And Sustainability Using Place-Based Learning: Three Examples, David Gosselin, Steven Burian, Tim Lutz, Julie Maxson
Department of Earth and Atmospheric Sciences: Faculty Publications
From water to energy, and from climate change to natural hazards, the geosciences (marine, Earth, and atmospheric science) have an important role to play in addressing a wide range of societal issues, with particular relevance to how humans can live sustainably on Earth. Although arguably important to developing solutions for many societal issues, more often than not, students have limited exposure to the geosciences in high school or college. To address this geoscience literacy problem, the Interdisciplinary Teaching of Geoscience for a Sustainable Future (InTeGrate) Talent Expansion Center has engaged members of the geoscience community and their colleagues in allied …
Global Analysis Of Saturation Artifacts In The Viirs Infrared Channels And The Effects Of Sample Aggregation, Thomas N. Polivka, Edward Hyer, Jun Wang, David A. Peterson
Global Analysis Of Saturation Artifacts In The Viirs Infrared Channels And The Effects Of Sample Aggregation, Thomas N. Polivka, Edward Hyer, Jun Wang, David A. Peterson
Department of Earth and Atmospheric Sciences: Faculty Publications
Unlike previous spaceborne Earth observing sensors, the Visible Infrared Imaging Radiometer Suite (VIIRS) employs onboard sample aggregation to reduce downlink bandwidth requirements and preserve spatial resolution across the scan. To examine the potentially deleterious impacts of onboard sample aggregation when encountering detector saturation, nearly four months of the National Oceanic and Atmospheric Administration’s Nightfire product are analyzed, which contains a subset of the hottest observed nighttime pixels. An empirical method for identifying saturation is devised. The M12 band (3.69 μm) is the most frequently saturating band with 0.15% of the Nightfire pixels at or near the ~359-K detector saturation limit; …
Atmospheric Circulation Processes Contributing To A Multidecadal Variation In Reconstructed And Modeled Indian Monsoon Precipitation, Qianru Wu, Qi Hu
Atmospheric Circulation Processes Contributing To A Multidecadal Variation In Reconstructed And Modeled Indian Monsoon Precipitation, Qianru Wu, Qi Hu
Department of Earth and Atmospheric Sciences: Faculty Publications
An analysis of the recently reconstructed gridded May–September total precipitation in the Indian monsoon region for the past half millennium discloses significant variations at multidecadal timescales. Meanwhile, paleo-climate modeling outputs from the National Center for Atmospheric Research Community Climate System Model 4.0 show similar multidecadal variations in the monsoon precipitation. One of those variations at the frequency of 40–50 years per cycle is examined in this study. Major results show that this variation is a product of the processes in that the meridional gradient of the atmospheric enthalpy is strengthened by radiation loss in the high-latitude and polar region. Driven …
Temporal Dynamics Of Groundwater-Dissolved Inorganic Carbon Beneath A Drought-Affected Braided Stream: Platte River Case Study, Audrey R. Boerner, John B. Gates
Temporal Dynamics Of Groundwater-Dissolved Inorganic Carbon Beneath A Drought-Affected Braided Stream: Platte River Case Study, Audrey R. Boerner, John B. Gates
Department of Earth and Atmospheric Sciences: Faculty Publications
Impacts of environmental changes on groundwater carbon cycling are poorly understood despite their potentially high relevance to terrestrial carbon budgets. This study focuses on streambed groundwater chemistry during a period of drought-induced river drying and consequent disconnection between surface water and groundwater. Shallow groundwater underlying vegetated and bare portions of a braided streambed in the Platte River (Nebraska, USA) was monitored during drought conditions in summer 2012. Water temperature and dissolved inorganic carbon (dominated by HCO3-) in streambed groundwater were correlated over a 3 month period coinciding with a decline in river discharge from 35 to 0 …
Thunderstorm Observation By Radar (Thor): An Algorithm To Develop A Climatology Of Thunderstorms, Adam L. Houston, Noah A. Lock, Jamie Lahowetz, Brian L. Barjenbruch, George L. Limpert, Cody Oppermann
Thunderstorm Observation By Radar (Thor): An Algorithm To Develop A Climatology Of Thunderstorms, Adam L. Houston, Noah A. Lock, Jamie Lahowetz, Brian L. Barjenbruch, George L. Limpert, Cody Oppermann
Department of Earth and Atmospheric Sciences: Faculty Publications
The Thunderstorm Observation by Radar (ThOR) algorithm is an objective and tunable Lagrangian approach to cataloging thunderstorms. ThOR uses observations from multiple sensors (principally multisite surveillance radar data and cloud-to-ground lightning) along with established techniques for fusing multisite radar data and identifying spatially coherent regions of radar reflectivity (clusters) that are subsequently tracked using a new tracking scheme. The main innovation of the tracking algorithm is that, by operating offline, the full data record is available, not just previous cluster positions, so all possible combinations of object sequences can be developed using all observed object positions. In contrast to Eulerian …
Diagenetic Incorporation Of Sr Into Aragonitic Bivalve Shells: Implications For Chronostratigraphic And Palaeoenvironmental Interpretations, Maria C. Marcano, Tracy D. Frank, Samuel B. Mukasa, Kyger C. Lohmann, Marco Taviani
Diagenetic Incorporation Of Sr Into Aragonitic Bivalve Shells: Implications For Chronostratigraphic And Palaeoenvironmental Interpretations, Maria C. Marcano, Tracy D. Frank, Samuel B. Mukasa, Kyger C. Lohmann, Marco Taviani
Department of Earth and Atmospheric Sciences: Faculty Publications
Aragonite is easily altered during diagenesis, therefore presumed pristine when present. In effect, beyond polymorphic transformation to calcite, alteration paths of aragonite remain poorly understood despite heavy reliance on such material to produce palaeoenvironmental and chronostratigraphic interpretations. Previous work on core material from Southern McMurdo Sound, Antarctica, showed that unlike their calcitic counterparts, seemingly unaltered aragonite shell fragments invariably produced older than expected 87Sr/86Sr ages. In this study, we pursued additional analyses of these aragonite shells and of the porewater of the core to understand this discrepancy. Aragonite mineralogy was reconfirmed and elemental mapping of shell fragments …
Trans-Amazon Drilling Project (Tadp): Origins And Evolution Of The Forests, Climate, And Hydrology Of The South American Tropics, P. A. Baker, S. C. Fritz, C. G. Silva, C. A. Rigsby, M. L. Absy, R. P. Almeida, M. Caputo, C. M. Chiessi, F. W. Cruz, C. W. Dick, S. J. Feakins, J. Figueiredo, K. H. Freeman, C. Hoorn, C. Jaramillo, A. K. Kern, E. M. Latrubesse, M. P. Ledru, A. Marzoli, A. Myrbo, A. Noren, W. E. Piller, M. I. F. Ramos, C. C. Ribas, R. Trnadade, A. J. West, I. Wahnfried, D. A. Willard
Trans-Amazon Drilling Project (Tadp): Origins And Evolution Of The Forests, Climate, And Hydrology Of The South American Tropics, P. A. Baker, S. C. Fritz, C. G. Silva, C. A. Rigsby, M. L. Absy, R. P. Almeida, M. Caputo, C. M. Chiessi, F. W. Cruz, C. W. Dick, S. J. Feakins, J. Figueiredo, K. H. Freeman, C. Hoorn, C. Jaramillo, A. K. Kern, E. M. Latrubesse, M. P. Ledru, A. Marzoli, A. Myrbo, A. Noren, W. E. Piller, M. I. F. Ramos, C. C. Ribas, R. Trnadade, A. J. West, I. Wahnfried, D. A. Willard
Department of Earth and Atmospheric Sciences: Faculty Publications
This article presents the scientific rationale for an ambitious ICDP drilling project to continuously sample Late Cretaceous to modern sediment in four different sedimentary basins that transect the equatorial Amazon of Brazil, from the Andean foreland to the Atlantic Ocean. The goals of this project are to document the evolution of plant biodiversity in the Amazon forests and to relate biotic diversification to changes in the physical environment, including climate, tectonism, and the surface landscape. These goals require long sedimentary records from each of the major sedimentary basins across the heart of the Brazilian Amazon, which can only be obtained …
Polarimetric Tornadic Debris Signature Variability And Debris Fallout Signatures, Matthew S. Van Den Broeke
Polarimetric Tornadic Debris Signature Variability And Debris Fallout Signatures, Matthew S. Van Den Broeke
Department of Earth and Atmospheric Sciences: Faculty Publications
Values of polarimetric radar variables may vary substantially between and through tornadic debris signature (TDS) events. Tornadoes with higher intensity ratings are associated with higher average and extreme values of reflectivity factor at horizontal polarization ZHH and lower values of copolar cross-correlation coefficient rhv. Although values of these variables often fluctuate through reported tornado life cycles, ZHH repeatably decreases and rhv repeatably increases across the volume scan immediately following reported tornado demise. Land cover has a relatively small effect on values of the polarimetric variables within TDSs, although near-radar urban TDSs may exhibit relatively high ZHH values. TDS areal extent …