96 research outputs found

    Geological and geophysical maps of the Illinois Basin-Ozark Dome region

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    Map 1. Land surface topography -- Map 2. Bedrock topography -- Map 3. Surficial geology with shaded relief -- Map 4. Bedrock geology with bedrock topography -- Map 5. Structure contours of the top of the Pennsylvanian Springfield Coal and Bevier Coal (Missouri) -- Map 6. Structure contours of the top of the Mississippian-Devonian New Albany Shale and correlatives -- Map 7. Structure contours of the top of the Ordovician Trenton Limestone (or equivalent) -- Map 8. Structure contours of the top of the Precambrian -- Map 9. Isostatic gravity anomaly -- Map 10. Magnetic anomaly -- Map 11. Fault and fold traces -- Map 12. Earthquake epicenters 1804-2014.Ope

    Transamazonian orogeny in the Southern S?o Francisco craton region, Minas Gerais, Brazil : evidence for paleoproterozoic collision and collapse in the Quadril?tero Ferr??fero.

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    The Paleoproterozoic Transamazonian orogeny yielded a series of discrete orogens in Brazil. The present field study in the Quadril?tero Ferr??fero (QF) indicates that the southern S?o Francisco craton region of the Brazilian highlands preserves a portion of one of these orogens. Two sets of Transamazonian structures occur in this region. The first consists of northwest-verging folds and thrusts affecting supracrustal sequences. It is suggested that this set formed in a fold-thrust belt setting shortly after 2.125 Ga, during the closure of a passive-margin basin that had initiated along the margins of a preexisting continental mass at ca 2.5 Ga. The second set consists of structures defining the prominent dome-and-keel architecture of the QF. This set, a consequence of the emplacement of basement domes against supracrustal rocks at 2.095 Ga, may reflect the consequences of orogenic collapse. Narrow, conglomerate-filled intermontane basins may have formed coevally with dome emplacement. Formation of an ocean basin east of the present-day S?o Francisco craton eventually occurred in Late Mesoproterozoic. In effect, the Transamazonian orogen of the QF represents the collision and collapse stages of a Paleoproterozoic Wilson cycle. The contractional phase of the Transamazonian orogeny probably represents accretion of an offshore arc to the eastern and southeastern margin of the present-day S?o Francisco craton region. The arc, and an associated suture, may be traced in the Brasiliano (Pan African) orogen east of the S?o Francisco craton, northwards into the northeastern lobe of the S?o Francisco craton. Clearly, initial assembly of crustal blocks to form a larger continent involving South America occurred during the Paleoproterozoic (2.1 Ga). Post-Transamazonian rifting of this continent created the basins which were later inverted during the Brasiliano assembly of Gondwana

    Assessment of Cloud Screening with Apparent Surface Reflectance in Support of the ICESat-2 Mission

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    The separation of cloud and clear scenes is usually one of the first steps in satellite data analysis. Before deriving a geophysical product, almost every satellite mission requires a cloud mask to label a scene as either clear or cloudy through a cloud detection procedure. For clear scenes, products such as surface properties may be retrieved; for cloudy scenes, scientist can focus on studying the cloud properties. Hence the quality of cloud detection directly affects the quality of most satellite operational and research products. This is certainly true for the Ice, Cloud, and land Elevation Satellite-2 (lCESat-2), which is the successor to the ICESat-l. As a top priority mission, ICESat-2 will continue to provide measurements of ice sheets and sea ice elevation on a global scale. Studies have shown that clouds can significantly affect the accuracy of the retrieved results. For example, some of the photons (a photon is a basic unit of light) in the laser beam will be scattered by cloud particles on its way. So instead of traveling in a straight line, these photons are scattered sideways and have traveled a longer path. This will result in biases in ice sheet elevation measurements. Hence cloud screening must be done and be done accurately before the retrievals

    First Satellite-detected Perturbations of Outgoing Longwave Radiation Associated with Blowing Snow Events over Antarctica

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    We present the first satellite-detected perturbations of the outgoing longwave radiation (OLR) associated with blowing snow events over the Antarctic ice sheet using data from Cloud-Aerosol Lidar with Orthogonal Polarization and Clouds and the Earth's Radiant Energy System. Significant cloud-free OLR differences are observed between the clear and blowing snow sky, with the sign andmagnitude depending on season and time of the day. During nighttime, OLRs are usually larger when blowing snow is present; the average difference in OLRs between without and with blowing snow over the East Antarctic Ice Sheet is about 5.2 W/m2 for the winter months of 2009. During daytime, in contrast, the OLR perturbation is usually smaller or even has the opposite sign. The observed seasonal variations and day-night differences in the OLR perturbation are consistent with theoretical calculations of the influence of blowing snow on OLR. Detailed atmospheric profiles are needed to quantify the radiative effect of blowing snow from the satellite observations

    Structural style of basin inversion at mid-crustal levels : two transects in the internal zone of the Brasiliano Ara?ua? belt, Minas Gerais, Brazil.

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    The Ara?uai belt is the orogenic belt that directly borders the eastern margin of the S?o Francisco Craton in eastern Brazil. Detailed structural investigations in the Governador Valadares region of Minas Gerais indicate that the amphibolite-to granulite-grade internal zones of the Ara?uai belt contain several major, west-vergent, crystalline overthrust sheets. These thrust sheets contain approximately homoclinal east-dipping gneissic banding and are separated from one another by zones of isoclinally and sheath-folded, ductiley sheared, metasedimentary units that behaved as mechanically weak glide horizons during deformation. We interpret this regionally imbricated sequence of basement and cover to be the mid-crustal level manifestation of closure of a mid-Neoproterozoic rift basin that existed to the east of the S?o Francisco Craton. The major thrusts, which are all cratonvergent, are of Brasiliano/Pan-African age (650-450 Ma) becuase they cut the Neoproterozoic Galil?ia batholith. Older fabrics are locally preserved in the basement slices, and these fabrics may be relicts of the Transamazonian orogeny (2.0 Ga). Discrete zones of ductile-brittle extension that were identified in several localities in the study area suggest the occurrence of postorogenic collapse following Brasiliano overthrusting. Alternations of rigid crystalline thrust sheets and highly deformed metasedimentary sequences, such as those of the Governador Valadares region, may be a common structural geometry at a depth of 15?20 km in modern regions of collision and basin closure

    A42A-04: Determination of Cloud Thermodynamic Phase with Ground Based, Polarimetrically Sensitive, Passive Sky Radiometers

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    When observed from the ground, optically thick clouds minimally polarize light, while the linear polarization direction (angle) of optically thin clouds contains information about thermodynamic phase. For instruments such at the Cimel radiometers that comprise the AErosol RObotic NEtwork (AERONET), these properties can also be exploited to aid cloud optical property retrievals. Using vector radiative transfer simulations, we explore the conditions most favorable to cloud thermodynamic phase determination, then test with actual AERONET data. Results indicate that this technique may be appropriate for some, but not all, conditions, and motivate a deeper investigation about the polarization direction measurement capability of Cimel instruments, which to date have been primarily used to determine degree of polarization. Recent work explores these measurement issues using a newly installed instrument at the NASA Ames Research Center in Moffett Field, California

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure
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