Sample records for southern marginal zone

  1. Imprint of Southern Red Sea Major Tectonic Zone In A New Bouguer Anomaly Map of Southern Yemen Margin (United States)

    Blecha, V.

    A new Bouguer anomaly map of western part of southern Yemen margin has been compiled. Densities of rock samples from main geological units (Precambrian base- ment, Mesozoic sediments, Tertiary volcanites) have been measured and used for grav- ity modeling. Regional gravity map indicates decrease of thickness of continental crust from volcanites of the Yemen Trap Series towards the coast of the Gulf of Aden. Most remarkable feature in the map of residual anomalies is a positive anomaly over the Dhala graben. The Dhala graben is a prominent geological structure in the area of study trending parallel to the Red Sea axis. Gravity modeling on a profile across the Dhala graben presumes intrusive plutonic rocks beneath the graben. There are two other areas in the southwestern tip of Arabia, which have essentially the same struc- tural position as the Dhala graben: the Jabal Tirf volcanic rift zone in the southern Saudi Arabia and Jabal Hufash extensional zone in northern Yemen. All three areas extend along the line trending parallel to the Red Sea axis with length of about 500 km. The line coincides with the axis of Afar (Danakil) depression after Arabia is shifted and rotated back to Africa. These facts imply conclusion that the Oligocene - Early Miocene magmatic activity on the Jabal Tirf - Dhala lineament is related to the same original deep tectonic zone, forming present-day Afar depression and still active.

  2. Ductile extension of syn-magmatic lower crusts, with application to volcanic passive margins: the Ivrea Zone (Southern Alps, Italy) (United States)

    Bidault, Marie; Geoffroy, Laurent; Arbaret, Laurent; Aubourg, Charles


    Deep seismic reflection profiles of present-day volcanic passive margins often show a 2-layered lower crust, from top to bottom: an apparently ductile 12 km-thick middle-lower layer (LC1) of strong folded reflectors and a 4 km-thick supra-Moho layer (LC2) of horizontal and parallel reflectors. Those layers appear to be structurally disconnected and to develop at the early stages of margins evolution. A magmatic origin has been suggested by several studies to explain those strong reflectors, favoring mafic sills intrusion hypothesis. Overlying mafic and acidic extrusives (Seaward Dipping Reflectors sequences) are bounded by continentward-dipping detachment faults rooting in, and co-structurated with, the ductile part of the lower crust (LC1). Consequently the syn-rift to post-rift evolution of volcanic passive margins (and passive margins in general) largely depends on the nature and the properties of the lower crust, yet poorly understood. We propose to investigate the properties and rheology of a magma-injected extensional lower crust with a field analogue, the Ivrea Zone (Southern Alps, Italy). The Ivrea Zone displays a complete back-thrusted section of a Variscan continental lower crust that first underwent gravitational collapse, and then lithospheric extension. This Late Paleozoic extension was apparently associated with the continuous intrusion of a large volume of mafic to acid magma. Both the magma timing and volume, and the structure of the Ivrea lower crust suggest that this section represents an adequate analogue of a syn-magmatic in-extension mafic rift zone which aborted at the end of the Permian. Notably, we may recognize the 2 layers LC1 and LC2. From a number of tectonic observations, we reconstitute the whole tectonic history of the area, focusing on the strain field evolution with time, in connection with mafic magma injection. We compare those results with available data from extensional mafic lower crusts at rifts and margins.

  3. Left-lateral transtension along the Tierra Colorada deformation zone, northern margin of the Xolapa magmatic arc of southern Mexico (United States)

    Riller, U.; Ratschbacher, L.; Frisch, W.


    Structural analysis of steeply NNW-dipping tectonites along the northern margin of the Xolapa magmatic arc, southern Mexico, reveals progressive deformation involving ductile and brittle deformation mechanisms. Ductile deformation detached Cretaceous cover rocks from the Xolapa basement along a crustal-scale mylonite zone with normal fault geometry. Normal faults dissected the mylonite zone into blocks which rotated a minimum of 35° to the north. Stress tensors calculated from fault-striae data show subhorizontal, roughly N/S-trending principal extension. Deformation resulted from differential uplift of the Xolapa magmatic arc with respect to its northern hinterland (Mixteca terrane). The oblique normal fault geometry of the mylonites conforms with strike-slip and dip-slip movements along the faults. Left-lateral transtension commenced ductilely between 90 Ma (age of deformed cover rocks) and 34 Ma (U/Pb zircon age of an undeformed pluton cutting the mylonite zone) and continued brittlely into the late Tertiary (tilted Miocene volcanic rocks). We argue that deformation resulted from the interaction of a left-lateral strike-slip regime established during formation of the Caribbean, and an extensional collapse of the Xolapa magmatic arc resulting from a change in steady-state plate-boundary conditions in the early Tertiary.

  4. Subduction Zone Dewatering at the Southern End of New Zealand's Hikurangi Margin - Insights from 2D Seismic Tomography (United States)

    Crutchley, G. J.; Klaeschen, D.


    The southern end of New Zealand's Hikurangi subduction margin is characterised by highly-oblique convergence as it makes a southward transition into a right-lateral transform plate boundary. Long-offset seismic data that cross part of the offshore portion of this transition zone give new insight into the nature of the margin. We have carried out two-dimensional pre-stack depth migrations with an iterative reflection tomography to update the velocity field on two seismic lines in this area. The depth-migrated sections show much-improved imaging of faulting within the wedge, and the seismic velocities themselves give clues about the distribution of gas and/or overpressured regions at the plate boundary and within the overlying wedge. A fascinating observation is a major splay fault that has been (or continues to be) a preferred dewatering pathway through the wedge, evidenced by a thermal anomaly that has left its mark on the overlying gas hydrate layer. Another interesting observation is a thick and laterally extensive low velocity zone beneath the subduction interface, which might have important implications for the long-term mechanical stability of the interface. Our on-going work on these data is focused on amplitude versus offset analysis in an attempt to better understand the nature of the subduction interface and also the shallower gas hydrate system. This study is an example of how distinct disturbances of the gas hydrate system can provide insight into subduction zone fluid flow processes that are important for understanding wedge stability and ultimately earthquake hazard.

  5. Air-sea interaction regimes in the sub-Antarctic Southern Ocean and Antarctic marginal ice zone revealed by icebreaker measurements (United States)

    Yu, Lisan; Jin, Xiangze; Schulz, Eric W.; Josey, Simon A.


    This study analyzed shipboard air-sea measurements acquired by the icebreaker Aurora Australis during its off-winter operation in December 2010 to May 2012. Mean conditions over 7 months (October-April) were compiled from a total of 22 ship tracks. The icebreaker traversed the water between Hobart, Tasmania, and the Antarctic continent, providing valuable in situ insight into two dynamically important, yet poorly sampled, regimes: the sub-Antarctic Southern Ocean and the Antarctic marginal ice zone (MIZ) in the Indian Ocean sector. The transition from the open water to the ice-covered surface creates sharp changes in albedo, surface roughness, and air temperature, leading to consequential effects on air-sea variables and fluxes. Major effort was made to estimate the air-sea fluxes in the MIZ using the bulk flux algorithms that are tuned specifically for the sea-ice effects, while computing the fluxes over the sub-Antarctic section using the COARE3.0 algorithm. The study evidenced strong sea-ice modulations on winds, with the southerly airflow showing deceleration (convergence) in the MIZ and acceleration (divergence) when moving away from the MIZ. Marked seasonal variations in heat exchanges between the atmosphere and the ice margin were noted. The monotonic increase in turbulent latent and sensible heat fluxes after summer turned the MIZ quickly into a heat loss regime, while at the same time the sub-Antarctic surface water continued to receive heat from the atmosphere. The drastic increase in turbulent heat loss in the MIZ contrasted sharply to the nonsignificant and seasonally invariant turbulent heat loss over the sub-Antarctic open water.Plain Language SummaryThe icebreaker Aurora Australis is a research and supply vessel that is regularly chartered by the Australian Antarctic Division during the southern summer to operate in waters between Hobart, Tasmania, and Antarctica. The vessel serves as the main lifeline to three permanent research stations on the

  6. The Two Subduction Zones of the Southern Caribbean: Lithosphere Tearing and Continental Margin Recycling in the East, Flat Slab Subduction and Laramide-Style Uplifts in the West (United States)

    Levander, A.; Bezada, M. J.; Niu, F.; Schmitz, M.


    The southern Caribbean plate boundary is a complex strike-slip fault system bounded by oppositely vergent subduction zones, the Antilles subduction zone in the east, and a currently locked Caribbean-South American subduction zone in the west (Bilham and Mencin, 2013). Finite-frequency teleseismic P-wave tomography images both the Atlanic (ATL) and the Caribbean (CAR) plates subducting steeply in opposite directions to transition zone depths under northern South America. Ps receiver functions show a depressed 660 discontinuity and thickened transition zone associated with each subducting plate. In the east the oceanic (ATL) part of the South American (SA) plate subducts westward beneath the CAR, initiating the El Pilar-San Sebastian strike slip system, a subduction-transform edge propagator (STEP) fault (Govers and Wortel, 2005). The point at which the ATL tears away from SA as it descends into the mantle is evidenced by the Paria cluster seismicity at depths of 60-110 km (Russo et al, 1993). Body wave tomography and lithosphere-asthenosphere boundary (LAB) thickness determined from Sp and Ps receiver functions and Rayleigh waves suggest that the descending ATL also viscously removes the bottom third to half of the SA continental margin lithospheric mantle as it descends. This has left thinned continental lithosphere under northern SA in the wake of the eastward migrating Antilles subduction zone. The thinned lithosphere occupies ~70% of the length of the El Pilar-San Sebastian fault system, from ~64oW to ~69oW, and extends inland several hundred kilometers. In northwestern SA the CAR subducts east-southeast at low angle under northern Colombia and western Venezuela. The subducting CAR is at least 200 km wide, extending from northernmost Colombia as far south as the Bucaramanga nest seismicity. The CAR descends steeply under Lake Maracaibo and the Merida Andes. This flat slab is associated with three Neogene basement cored, Laramide-style uplifts: the Santa Marta

  7. How the gas hydrate system gives insight into subduction wedge dewatering processes in a zone of highly-oblique convergence on the southern Hikurangi margin of New Zealand (United States)

    Crutchley, Gareth; Klaeschen, Dirk; Pecher, Ingo; Henrys, Stuart


    The southern end of New Zealand's Hikurangi subduction margin is characterised by highly-oblique convergence as it makes a southward transition into a right-lateral transform plate boundary at the Alpine Fault. Long-offset seismic data that cross part of the offshore portion of this transition zone give new insight into the nature of the plate boundary. We have carried out 2D pre-stack depth migrations, with an iterative reflection tomography to update the velocity field, on two seismic lines in this area to investigate fluid flow processes that have implications for the mechanical stability of the subduction interface. The results show distinct and focused fluid expulsion pathways from the subduction interface to the shallow sub-surface. For example, on one of the seismic lines there is a clear disruption of the gas hydrate system at its intersection with a splay fault - a clear indication of focused fluid release from the subduction interface. The seismic velocities derived from tomography also highlight a broad, pronounced low velocity zone beneath the deforming wedge that we interpret as a thick zone of gas-charged fluids that may have important implications for the long-term frictional stability of the plate boundary in this area. The focused flow upward toward the seafloor has the potential to result in the formation of concentrated gas hydrate deposits. Our on-going work on these data will include amplitude versus offset analysis in an attempt to better characterise the nature of the subduction interface, the fluids in that region, and also the shallower gas hydrate system.

  8. Marginal Ice Zone: Biogeochemical Sampling with Gliders (United States)


    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Marginal Ice Zone: Biogeochemical Sampling with Gliders...under the ice and in the marginal ice zone. The project specific goals are to develop biogeochemical and optical proxies for glider optics; to use the...water, in the marginal ice zone, and under the ice; to use glider optical measurements to compute fields of rates of photosynthetic carbon fixation

  9. Primary extranodal marginal zone lymphoma - Epididymis

    Directory of Open Access Journals (Sweden)

    Shanmugasundaram Rajaian


    Full Text Available An elderly male presented with painful swelling in the right side of scrotum. He was treated with antibiotics for epididymoorchitis without any response. Ultrasound examination revealed a hypoechoic vascular mass in the tail of the epididymis. Fine needle aspirate cytology was inconclusive. Excision of the mass was done and biopsy revealed primary extranodal marginal zone lymphoma arising from mucosa associated lymphoid tissue (MALT of epididymis. Marginal zone lymphoma arising from the MALT of epididymis is very rare. Lymphoma should be considered as a differential diagnosis of any epididymal swelling unresponsive to conservative treatment. We report a rare case of primary extranodal marginal lymphoma of MALT arising from epididymis.

  10. Heavy mineral provinces of the Palos Verdes margin, southern California (United States)

    Wong, Florence L.


    Natural sources of sediment for the Palos Verdes margin, southern California, have been augmented by effluent discharged from Los Angeles County Sanitation District's sewage-treatment facility and by the reactivation of the Portuguese Bend landslide. Heavy minerals in very fine and fine sand (63-250 μm) from beach and shelf sites off the Palos Verdes Peninsula distinguish effluent-affected sediment from unaffected deposits, and track the sediment contributed by the Portuguese Bend landslide. Heavy minerals also identify heterogeneous sediment sources for the nearshore zone and relate outer-shelf sediment to depositional cells north and south of the area.

  11. Marginal Ice Zone Flux and Variability (United States)

    Pfirman, S. L.; Tremblay, B.; Newton, R.; Fowler, C.


    Arctic sea ice acts as a conveyor, collecting and transporting material across the central basin, and releasing it in the marginal ice zone (MIZ). Where and when ice with different transport histories melts, has a large impact on the MIZ and is critical for understanding the vulnerability of the Arctic system to climate change. This study focuses on the effects of changing the location and timing of fluxes to the MIZ, as well as the age and origin of ice delivered there. Combining observations and models, we analyze sea ice motion for origin, age, drift path, and flux (both along the drift path and to the MIZ) for past, recent, and future scenarios. We examine temporal and spatial variations in the transport of sea ice and ice-rafted material between different source and melt regions for interannual and seasonal variability, including: a) How the distribution, origin, and age of ice delivered to various MIZs has changed over time, especially during the spring bloom. b) How changes in ice drift related to changes in atmospheric, oceanic, sedimentologic, and ecologic conditions have influenced the delivery of freshwater, sediments, and biological material. c) How changes have varied regionally and with respect to water depth. For example, whether maximum ice melt - and therefore material release - occurs over deep waters or shallow shelves is an important ecological parameter. As the Arctic transitions toward ice free summer conditions, the seasonal ice zone will expand, shifting the location of the marginal ice zone. It is critical to understand processes governing these changes because the MIZ is the most dynamic, most productive, and most vulnerable region in the Arctic.

  12. Surgical management of splenic marginal zone lymphoma. (United States)

    Kennedy, N D; Lê, G N; Kelly, M E; Harding, T; Fadalla, K; Winter, D C


    Splenic marginal zone lymphoma (SMZL) is a rare indolent B-cell lymphoma with variable prognosis. As a result, there is sparse knowledge on the role of splenectomy and best management approaches. We aim to explore management strategies and outcomes amongst the cohort of SMZL patients at our centre. A retrospective review of all splenectomies performed at a tertiary referral unit over a 23-year period was assessed. Immunohistochemical and pathological results of splenic samples, bone marrow biopsies, and peripheral blood were compiled. Operative management, surgical, and survival outcomes were assessed. Prognostic stratifications were applied and survival rates were calculated. Eight cases of SMZL from a database of 693 splenectomies were identified. All patients had intermediate/high-risk disease. All patients underwent splenectomy with one patient receiving preoperative rituximab. All patients had progression-free survival and resolution of disease. Based on the data obtained, current practice requires defined guidelines and centralised care.

  13. Waves and Fetch in the Marginal Ice Zone (United States)


    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Waves and fetch in the Marginal Ice Zone Jim Thomson... Marginal Ice Zone (MIZ) by improving basic understanding of the interaction between waves, sea ice, and open water (i.e., fetch). OBJECTIVES The...for deployments in the marginal ice zone. Color scale is ice concentration. 3 Figure 2. Example estimates of fetch distance analysis in

  14. Air-Sea Interactions in the Marginal Ice Zone (United States)


    Journal article postprint 3. DATES COVERED (From - To) 01/01/2012 - 30/09/2016 4. TITLE AND SUBTITLE Waves & Fetch in the Marginal Ice Zone...5a. CONTRACT NUMBER Air-sea interactions in the marginal ice zone 5b. GRANT NUMBER N00014-12-1-0113 5c. PROGRAM Air-sea interactions in the marginal ice zoneAir-Sea interactions in the Marginal Ice Zone Seth Zippel1* • Jim Thomson1 1Applied

  15. The origin of marginal zone B cells in the rat

    NARCIS (Netherlands)

    Dammers, PM; de Boer, NK; Deenen, GJ; Nieuwenhuis, P; Kroese, FGM

    The marginal zone is a unique compartment that is only found in the spleen. Rat marginal zone B cells (MZ-B) can be distinguished from other B cells, e.g. recirculating follicular B cells (RF-B), by several phenotypic characteristics. Typically MZ-B cells are surface (s)IgM(hi), sIgD(lo) and

  16. Extranodal marginal zone (MALT) lymphoma in common variable immunodeficiency.

    NARCIS (Netherlands)

    Desar, I.M.; Keuter, M.; Raemaekers, J.M.M.; Jansen, J.B.M.J.; Krieken, J.H.J.M. van; Meer, J.W.M. van der


    We describe two patients with common variable immunodeficiency (CVID) who developed extranodal marginal zone lymphoma (formerly described as mucosa-associated lymphoid tissue lymphoma or MALT lymphoma). One patient, with documented pernicious anaemia and chronic atrophic gastritis with metaplasia,

  17. Reconstructing the Avalon continent: Marginal to inner platform transition in the Cambrian of southern New Brunswick (United States)

    Landing, E.


    A west to east, marginal to inner Avalonian platform transition, comparable to that in southeast Newfoundland and southern Britain, is present in the Cambrian of southern New Brunswick. The Saint John - Caton's Island - Hanford Brook area lay on the marginal platform, and its thick, uppermost Precambrian - lower Lower Cambrian is unconformably overlain by trilobite-bearing, upper Lower Cambrian. An inner platform remnant is preserved in the Cradle Brook outlier 60 km northeast of Saint John. In contrast to the marginal platform sequences, the Cradle Brook outlier has a very thin lower Lower Cambrian and has middle Lower Cambrian strata (Bonavista Group) not present on the marginal platform. The Cradle Brook Lower Cambrian closely resembles inner platform successions in eastern Massachusetts and Trinity and Placentia bays, southeast Newfoundland. A limestone with Camenella baltica Zone fossils on Cradle Brook seems to be the peritidal limestone cap of the subtrilobitic Lower Cambrian known in Avalonian North America (Fosters Point Formation) and England (Home Farm Member).

  18. (Tele)presenting Secrets from the Deep Southern California Margin (United States)

    Levin, L. A.; Girguis, P. R.; Brennan, M.; German, C. R.; Raineault, N.; Le, J. T.; Grupe, B.; Gallo, N.; Inderbitzen, K. E.; Tuzun, S.; Wagner, J.


    This past summer scientists, students and the public participated through telepresence in 2 weeks of deep-sea exploration via the EV Nautilus, visiting a tremendous diversity of sites found along the southern California continental margin (200-900m). We observed previously unknown cold seeps; new and unexpected assemblages and species distributions; and novel animal behaviors; all under the overarching influence of strong oxygen gradients from the East Pacific oxygen minimum zone (OMZ). The expedition discovered four new methane seep sites, each with distinct biota reflecting varying depth and oxygen levels. OMZ specialists such as lucinid clams, hagfish, and thornyhead fishes coexisted with seep biota (vesicoymid clams) at a 1.4-km long seep off Point Dume (Malibu, CA), forming a blended ecosystem with distinct zonation. A range of habitats (canyons, knolls, mounds) within the OMZ hosted fish, crustacean, echinoderm and cnidarian species with unusual hypoxia tolerance to important roles in environmental management of the deep ocean as disturbance from resource extraction and climate change intensify.

  19. Heterogeneity of memory marginal zone B cells in the rat

    NARCIS (Netherlands)

    Hendricks, Jacobus


    The spleen is an important organ of the immune system. Like other lymphoid organs, the spleen is compartmentalized. Different compartments harbor different populations of lymphocytes, subpopulation of the white blood cells. One of these compartments in the spleen is the so-called marginal zone. Most

  20. Physical properties of southern Alaska margin sediments in the context of global convergent margins (United States)

    Daigle, H.; Piña, O.; Screaton, E.; James, S.


    At convergent margins, the deformation response due to external forcing by sedimentation, tectonic stress, and volume changes during chemical reactions is closely interrelated with the ability of excess pore pressure to dissipate. These excess pore pressures in turn can affect plate boundary fault location and strength, rates of sediment accretion or subduction, the taper angle of material on the overriding plate, and may also play a role in the generation of earthquakes and propagation of seismic slip. Offshore southern Alaska, rapid sedimentation and glacial loading are interpreted to have influenced the location of thrust faulting by rapid transport of sediment offshore, where previously active faults were deactivated by increased normal stresses as a result of sediment loading. The response of the wedge to external forcing is linked to permeability of the wedge sediments, as well as those in the underriding plate. We determined permeability of sediments from the glacial sediment dominated accretionary wedge, sampled at Sites U1420 and U1421 on the Yakutat Block, and sediments from the Surveyor Fan that overlies the Pacific Plate and are inputs to the Aleutian Trench, sampled at Sites U1417 and U1418. We found that the Surveyor Fan sediments have porosity-permeability relationships that are comparable to sediments from other reference sites worldwide. However, the sediments in the wedge have somewhat higher permeability, much larger grain sizes, and are much less compressible compared with other wedge sediments. This suggests that the physical properties that control overpressure generation and dissipation in the input sediments to the Aleutian Trench are comparable to other subduction zones, but that the accretionary wedge on the Yakutat Block is uniquely strong and well-drained due to the predominance of glacigenic sediments.

  1. Wave-ice Interaction and the Marginal Ice Zone (United States)


    single buoys that were moved from place to place. These new data, obtained within the comprehensive set of ocean, ice and atmosphere sensors and remote...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Wave- ice interaction and the Marginal Ice Zone Prof...between ocean waves and a sea ice cover, in terms, of scattering, attenuation, and mechanical effect of the waves on the ice . OBJECTIVES The

  2. Long-term outcome for gastric marginal zone lymphoma treated with radiotherapy

    DEFF Research Database (Denmark)

    Wirth, A; Gospodarowicz, M; Aleman, B M P


    We evaluated the long-term results of radiotherapy for patients with gastric marginal zone lymphoma (GMZL).......We evaluated the long-term results of radiotherapy for patients with gastric marginal zone lymphoma (GMZL)....

  3. Paediatric nodal marginal zone B cell lymphadenopathy of the neck : a Haemophilus influenzae driven immune disorder?

    NARCIS (Netherlands)

    Kluin, Philip M.; Langerak, Anton W.; Beverdam-Vincent, Jannetta; Geurts-Giele, Willemina R. R.; Visser, Lydia; Rutgers, Bea; Schuuring, Ed; Van Baarlen, Joop; Lam, King H.; Seldenrijk, Kees; Kibbelaar, Robby E.; de Wit, Peter; Diepstra, Arjan; Rosati, Stefano; van Noesel, Max M.; Zwaan, C. Michel; Hunting, Jarmo C. B.; Hoogendoorn, Mels; van der Gaag, Ellen J.; van Esser, Joost W. J.; de Bont, Eveline; Kluin-Nelemans, Hanneke C.; Winter, Rik H.; Lo ten Foe, Jerome R.; van der Zanden, Adri G. M.

    Many hyperplasias and lymphomas of marginal zone B-cells are associated with infection. We identified 6 children and 1 adolescent with cervical lymphadenopathy showing a prominent polyclonal nodal marginal zone hyperplasia (pNMZH) and 4 adolescents with monoclonal paediatric nodal marginal zone

  4. Post Rift Evolution of the Indian Margin of Southern Africa (United States)

    Baby, Guillaume; Guillocheau, François; Robin, Cécile; Dall'asta, Massimo


    The objective of this study is to discuss the evolution of the South African Plateau along the Indian margin of Southern Africa. Since the classical works of A. du Toit and L.C. King and the improvement of thermochronological methods and numerical models, the question of the uplift of South African Plateau was highly debated with numerous scenarios: early Cretaceous at time of rifting (Van der Beek et al., J.Geophys.Res., 2002), late Cretaceous (Braun et al., Solid Earth, 2014), late Cenozoic (Burke & Gunnell, Geol.Soc.of America, 2008). Limited attention has been paid on the constraints provided by the offshore stratigraphic record of the surrounding margins. The objective of our study is to integrate onshore and offshore data (seismic profiles and industrial wells) to (1) analyse the infill of the whole margin (21°S to 31°S) from its hinterland to the distal deep water basin, (2) to constrain and quantify the vertical movements. We discuss the impact on accommodation and sediments partitioning, and their significance on South African Plateau uplift history. 1. Sedimentary basins of the Indian margin of Southern Africa are related to the break-up of Gondwana during late Jurassic, resulting in rifts and flexural basins. First marine incursions started during early Cretaceous times (oldest marine outcropping sediments are of Barremian age ~128 Ma). The region developed as a normal continental shelf at the Aptian-Albian transition (~113 Ma). 2. The Cretaceous geological history of the basins is characterized by differential uplift and subsidence of the basement, controlled by structures inherited from break up. As example, major early Cretaceous depocenters of the margin are located on the north of Save-Limpopo uplift (Forster, Paleogography, Paleoclimatology, Paleoecology, 1975) showing an eastward drainage pattern, maybe related to a proto Limpopo drainage. Those observations suggest that the escarpment bordering the Bushveld depression is an old relief inherited

  5. Dissecting the gray zone between follicular lymphoma and marginal zone lymphoma using morphological and genetic features

    NARCIS (Netherlands)

    Krijgsman, Oscar; Gonzalez, Patricia; Ponz, Olga Balague; Roemer, Margaretha G. M.; Slot, Stefanie; Broeks, Annegien; Braaf, Linde; Kerkhoven, Ron M.; Bot, Freek; van Groningen, Krijn; Beijert, Max; Ylstra, Bauke; de Jongi, Daphne


    Nodal marginal zone lymphoma is a poorly defined entity in the World Health Organization classification, based largely on criteria of exclusion and the diagnosis often remains subjective. Follicular lymphoma lacking t(14;18) has similar characteristics which results in a major potential diagnostic

  6. Marginal Ice Zone Processes Observed from Unmanned Aerial Systems (United States)

    Zappa, C. J.


    Recent years have seen extreme changes in the Arctic. Marginal ice zones (MIZ), or areas where the "ice-albedo feedback" driven by solar warming is highest and ice melt is extensive, may provide insights into the extent of these changes. Furthermore, MIZ play a central role in setting the air-sea CO2 balance making them a critical component of the global carbon cycle. Incomplete understanding of how the sea-ice modulates gas fluxes renders it difficult to estimate the carbon budget in MIZ. Here, we investigate the turbulent mechanisms driving mixing and gas exchange in leads, polynyas and in the presence of ice floes using both field and laboratory measurements. Measurements from unmanned aerial systems (UAS) in the marginal ice zone were made during 2 experiments: 1) North of Oliktok Point AK in the Beaufort Sea were made during the Marginal Ice Zone Ocean and Ice Observations and Processes EXperiment (MIZOPEX) in July-August 2013 and 2) Fram Strait and Greenland Sea northwest of Ny-Ålesund, Svalbard, Norway during the Air-Sea-Ice Physics and Biogeochemistry Experiment (ASIPBEX) April - May 2015. We developed a number of new payloads that include: i) hyperspectral imaging spectrometers to measure VNIR (400-1000 nm) and NIR (900-1700 nm) spectral radiance; ii) net longwave and net shortwave radiation for ice-ocean albedo studies; iii) air-sea-ice turbulent fluxes as well as wave height, ice freeboard, and surface roughness with a LIDAR; and iv) drone-deployed micro-drifters (DDµD) deployed from the UAS that telemeter temperature, pressure, and RH as it descends through the atmosphere and temperature and salinity of the upper meter of the ocean once it lands on the ocean's surface. Visible and IR imagery of melting ice floes clearly defines the scale of the ice floes. The IR imagery show distinct cooling of the skin sea surface temperature (SST) as well as an intricate circulation and mixing pattern that depends on the surface current, wind speed, and near

  7. Propagation and Directional Scattering of Ocean Waves in the Marginal Ice Zone and Neighboring Seas (United States)


    the Marginal Ice Zone and Neighboring Seas William Perrie Bedford Institute of Oceanography 1 Challenger Dr. Dartmouth, Nova Scotia B2Y 4A2...the spatial and temporal variability of sea state, and improve forecasting of waves on the open ocean and in the marginal ice zone; 2. Develop an...the Beaufort and Chukchi Seas, of relevance to oil and gas exploitation. This project also involves wave-ice interactions in the marginal ice zone, MIZ

  8. An Observational and Analytical Study of Marginal Ice Zone Atmospheric Jets (United States)


    AND ANALYTICAL STUDY OF MARGINAL ICE ZONE ATMOSPHERIC JETS by David M. Price December 2016 Thesis Advisor: Peter Guest Second Reader...DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE AN OBSERVATIONAL AND ANALYTICAL STUDY OF MARGINAL ICE ZONE ATMOSPHERIC JETS 5. FUNDING NUMBERS 6...12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) Low-level atmospheric jets have been observed to occur frequently in marginal ice zones (MIZs

  9. Ice, Ocean and Atmosphere Interactions in the Arctic Marginal Ice Zone (United States)


    release; distribution is unlimited. DRI TECHNICAL PROGRAM: Emerging Dynamics Of The Marginal Ice Zone Ice, Ocean and Atmosphere Interactions in the...Arctic Marginal Ice Zone Year 4 Annual Report Jeremy Wilkinson British Antarctic Survey phone: 44 (0)1223 221489 fax: 44 (0) LONG-TERM GOALS This DRI TECHNICAL PROGRAM (Emerging Dynamics Of The Marginal Ice Zone) brings together a high-level

  10. An Integrative Wave Model for the Marginal Ice Zone Based on a Rheological Parameterization (United States)


    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. An Integrative Wave model for the Marginal Ice LONG-TERM GOALS To enhance wave forecasting models such as WAVEWATCH III (WW3) so that they can predict the marginal ice zone (MIZ...Antarctic marginal ice zone were used to evaluate the viscoelastic ice damping models. The 2012 data came from two buoys separated by over 100km

  11. Evolution of the Marginal Ice Zone: Adaptive Sampling with Autonomous Gliders (United States)


    access marginal ice zone . When operating in ice-covered waters, gliders navigate by trilateration from acoustic sound sources (or dead reckoning should...release; distribution is unlimited. Evolution of the Marginal Ice Zone : Adaptive Sampling with Autonomous Gliders Craig M. Lee, Luc Rainville and Jason I...edge after one week. All for gliders did several sections from the open ocean, through the marginal ice zone , to the fully ice-covered ocean (Fig. 1

  12. Back-arc basin opening and closure along the southern margin of the Sea of Japan (United States)

    Sato, Hiroshi; Claringbould, Johan; Ishiyama, Tatsuya; Kato, Naoko; Abe, Susumu; Kawasaki, Shinji


    Following the tsunami disaster produced by 2001 Off-Tohoku earthquake (M9) along the Pacific coast of Japan, the Japanese government started an intense evaluation of tsunami hazards. This evaluation spanned along the full Japanese coast, including the Sea of Japan coast on the western side of the Japan arc. In the Sea of Japan, tsunamis are produced by crustal faults. As the longer interval of faulting activity, the historical records of tsunamis in the Sea of Japan are not enough for the evaluation of tsunami height. Thus, the evaluation is carried out based on structural analyses of the margin of the Sea of Japan. To get better understanding of the present-day structural geometry and develop a source-fault model in this region, intense seismic reflection profiling has been carried out since 2013. We introduce the results of the seismic reflection profiles and discuss the structural evolution of the southern margin of the Sea of Japan. 2D seismic reflection profiles were acquired using 1950 cu. in. air-gun and 2100 m streamer cable. The seismic profiles provide the image image up to 3 seconds TWT. The southern margin of the Sea of Japan was produced by back-arc opening and post-rift deformation, and the structural evolution of this area is divided into several stages: rifting (25 - 14 Ma), post-rift compression (14 - 5 Ma), weak thrusting (5 - 1 Ma), and strike-slip deformation (1 Ma to present). During the rifting stage that is associated with the fan-shaped opening of the Sea of Japan, grabens and half-grabens were formed trending parallel to the extension of SW-Japan arc. These grabens were filled by syn-rift sediments, and the maximum thickness of basin fill is observed along the southern margin of the rifted crust. The opening of the Sea of Japan ceased as a result of the collision of Izu-Bonin-Mariana arc system at the Izu collision zone on the central part of Honshu, Japan. Soon after the this event, the young Shikoku basin within the Philippine Sea plate

  13. Modeling Wave-Ice Interactions in the Marginal Ice Zone (United States)

    Orzech, Mark; Shi, Fengyan; Bateman, Sam; Veeramony, Jay; Calantoni, Joe


    The small-scale (O(m)) interactions between waves and ice floes in the marginal ice zone (MIZ) are investigated with a coupled model system. Waves are simulated with the non-hydrostatic finite-volume model NHWAVE (Ma et al., 2012) and ice floes are represented as bonded collections of smaller particles with the discrete element system LIGGGHTS (Kloss et al., 2012). The physics of fluid and ice are recreated as authentically as possible, to allow the coupled system to supplement and/or substitute for more costly and demanding field experiments. The presentation will first describe the development and validation of the coupled system, then discuss the results of a series of virtual experiments in which ice floe and wave characteristics are varied to examine their effects on energy dissipation, MIZ floe size distribution, and ice pack retreat rates. Although Wadhams et al. (1986) suggest that only a small portion (roughly 10%) of wave energy entering the MIZ is reflected, dissipation mechanisms for the remaining energy have yet to be delineated or measured. The virtual experiments are designed to focus on specific properties and processes - such as floe size and shape, collision and fracturing events, and variations in wave climate - and measure their relative roles the transfer of energy and momentum from waves to ice. Questions to be examined include: How is energy dissipated by ice floe collisions, fracturing, and drag, and how significant is the wave attenuation associated with each process? Do specific wave/floe length scale ratios cause greater wave attenuation? How does ice material strength affect the rate of wave energy loss? The coupled system will ultimately be used to test and improve upon wave-ice parameterizations for large-scale climate models. References: >Kloss, C., C. Goniva, A. Hager, S. Amberger, and S. Pirker (2012). Models, algorithms and validation for opensource DEM and CFD-DEM. Progress in Computational Fluid Dynamics 12(2/3), 140-152. >Ma, G

  14. Upper Ocean Evolution Across the Beaufort Sea Marginal Ice Zone (United States)

    Lee, C.; Rainville, L.; Gobat, J. I.; Perry, M. J.; Freitag, L. E.; Webster, S.


    The observed reduction of Arctic summertime sea ice extent and expansion of the marginal ice zone (MIZ) have profound impacts on the balance of processes controlling sea ice evolution, including the introduction of several positive feedback mechanisms that may act to accelerate melting. Examples of such feedbacks include increased upper ocean warming though absorption of solar radiation, elevated internal wave energy and mixing that may entrain heat stored in subsurface watermasses (e.g., the relatively warm Pacific Summer and Atlantic waters), and elevated surface wave energy that acts to deform and fracture sea ice. Spatial and temporal variability in ice properties and open water fraction impact these processes. To investigate how upper ocean structure varies with changing ice cover, how the balance of processes shift as a function of ice fraction and distance from open water, and how these processes impact sea ice evolution, a network of autonomous platforms sampled the atmosphere-ice-ocean system in the Beaufort, beginning in spring, well before the start of melt, and ending with the autumn freeze-up. Four long-endurance autonomous Seagliders occupied sections that extended from open water, through the marginal ice zone, deep into the pack during summer 2014 in the Beaufort Sea. Gliders penetrated up to 200 km into the ice pack, under complete ice cover for up to 10 consecutive days. Sections reveal strong fronts where cold, ice-covered waters meet waters that have been exposed to solar warming, and O(10 km) scale eddies near the ice edge. In the pack, Pacific Summer Water and a deep chlorophyll maximum form distinct layers at roughly 60 m and 80 m, respectively, which become increasingly diffuse late in the season as they progress through the MIZ and into open water. Stratification just above the Pacific Summer Water rapidly weakens near the ice edge and temperature variance increases, likely due to mixing or energetic vertical exchange associated with strong

  15. Submesoscale Sea Ice-Ocean Interactions in Marginal Ice Zones (United States)

    Manucharyan, Georgy E.; Thompson, Andrew F.


    Signatures of ocean eddies, fronts, and filaments are commonly observed within marginal ice zones (MIZs) from satellite images of sea ice concentration, and in situ observations via ice-tethered profilers or underice gliders. However, localized and intermittent sea ice heating and advection by ocean eddies are currently not accounted for in climate models and may contribute to their biases and errors in sea ice forecasts. Here, we explore mechanical sea ice interactions with underlying submesoscale ocean turbulence. We demonstrate that the release of potential energy stored in meltwater fronts can lead to energetic submesoscale motions along MIZs with spatial scales O(10 km) and Rossby numbers O(1). In low-wind conditions, cyclonic eddies and filaments efficiently trap the sea ice and advect it over warmer surface ocean waters where it can effectively melt. The horizontal eddy diffusivity of sea ice mass and heat across the MIZ can reach O(200 m2 s-1). Submesoscale ocean variability also induces large vertical velocities (order 10 m d-1) that can bring relatively warm subsurface waters into the mixed layer. The ocean-sea ice heat fluxes are localized over cyclonic eddies and filaments reaching about 100 W m-2. We speculate that these submesoscale-driven intermittent fluxes of heat and sea ice can contribute to the seasonal evolution of MIZs. With the continuing global warming and sea ice thickness reduction in the Arctic Ocean, submesoscale sea ice-ocean processes are expected to become increasingly prominent.

  16. Crustal structure north of the Taiping Island (Itu Aba Island), southern margin of the South China Sea (United States)

    Chang, Jih-Hsin; Hsieh, Hsien-Hsiang; Mirza, Arif; Chang, Sung-Ping; Hsu, Ho-Han; Liu, Char-Shine; Su, Chih-Chieh; Chiu, Shye-Donq; Ma, Yu-Fang; Chiu, Ying-Hui; Hung, Hau-Ting; Lin, Yen-Chun; Chiu, Chien-Hsuan


    Based on the multi-channel seismic (MCS) and gravity data offshore north of Taiping Island (Itu Aba Island) in the Spratly Islands (Nansha Islands), we revisited the crustal structures in the northern part of the southern margin of the Southwest (SW) Sub-basin of the South China Sea (SCS). The MCS data suggest that the basement structural highs in the southwest margin of the SCS are dominated by both fault blocks and volcanic basement structures that probably formed along with the basement faults. The gravity modeling results reveal that these volcanic basement structures were probably associated with the high velocity or density lower crust (HVDLC), suggesting that the southern margin of the SW Sub-basin serves as an intermediate margin. Based on the tectonic features in the SCS margins, including (1) the transition between the magma-poor margins of the Northwest (NW) Sub-basin and intermediate margins of the East and SW Sub-basins; (2) the cessation of the seafloor spreading in the NW Sub-basin being succeeded by a major ridge jump event, which was very likely to reflect an active mantle upwelling event; (3) the extensive distribution of the HVDLC beneath in the well-investigated northern margin of the East Sub-basin and as explored in the SW Sub-basin in this study; and (4) basement faulting and volcanism shown in this study that may be related to the HVDLC and hyper-extension, we proposed a conceptual model to interpret the origin of the HVDLC in the southern margin of the SW Sub-basin. The margin of the SCS basin was magma-poor at the time it occurred. An active mantle upwelling event caused by small-scale mantle convection, possibly related to the influence of the nascent Hainan mantle plume, was formed subsequently, resulting in a southward ridge jump and the HVDLC beneath the current margins of the East and SW Sub-basins. The East and SW Sub-basins continued to spread, latitudinally dividing their HVDLCs as the margins separated accordingly. Afterwards, the

  17. The oceanic segment of the southern Brazilian margin: Morpho-structural domains and their tectonic significance (United States)

    Bassetto, Marcelo; Alkmim, Fernando F.; Szatmari, Peter; Mohriak, Webster U.

    A descriptive and evolutionary analysis of the main morpho-structural features of the oceanic domain of the southern portion of the Brazilian Continental Margin is supported by regional seismic profiles and potential field data from the Brazilian governmental LEPLAC (Plano de Levantamento da Plataforma Continental Brasileira) Project. The several morpho-structural elements can be differentiated, as for example: the dominant structural pattern of the acoustic basement, including extensional faulting and long-wavelength folding, crustal thickness changes, fracture zones location, distribution of volcanic centers, and development of wedges of seaward-dipping reflectors. Four broad distinct morpho-structural domains, separated by fracture zones and oceanic lineaments. Domain I is located south of the Porto Alegre Lineament; Domain II corresponds to the area between the Porto Alegre Lineament and the Rio Grande Fracture Zone; Domain III spans the area of the São Paulo Plateau; and Domain IV is located to the east of this plateau, towards the abyssal portions of the oceanic crust. These domains are defined by their distinct regional morphologic and structural characteristics. Sometimes these elements are well imaged in the seismic profiles, corroborated by gravity and magnetic anomalies, and eventually identified as prominent features at the sea bottom physiography. Using a multidisciplinary approach based on bathymetric maps, regional seismic interpretation, magnetic data analysis, and gravity models, this work attempts to characterize these elements in a descriptive and evolutionary view, identifying their role in the tectonic development of this portion of the South Atlantic.

  18. Coastal zone management around the southern North Sea

    NARCIS (Netherlands)

    Hillen, R.; Van de Wetering, B.G.M.; Verhagen, H.J.


    The Southern North Sea is bordered by Great-Britain, France, Belgium, The Netherlands, Germany and Denmark. The North Sea basin and its adjacent shorelines are intensively used. Management of the basin and the coastal zone is therefore essential. Because of the small scale of the area, the dense

  19. Marginal Ice Zone (MIZ) Program: Science and Experiment Plan (United States)


    followed by a Fram Strait ice edge component called SIZEX (Seasonal Ice Zone Experiment) (Johannessen and Sandven, 1989) in early spring 1989. The focus...from the Arctic Basin through Fram Strait as sea ice (about 105 m3 s −1) is roughly comparable to the total continental runoff entering the basin. In...summer. A project timeline (Figure 3) provides an overview of field operations. The flexible nature of ice- mounted and mobile, autonomous oceanographic

  20. Radiocarbon geochronology of the sediments of the Sao Paulo bight (Southern Brazilian upper margin)

    Energy Technology Data Exchange (ETDEWEB)

    Mahiques, Michel M.; Sousa, Silvia H.M.; Burone, Leticia; Nagai, Renata H.; Silveira, Ilson C.A.; Figueira, Rubens C.L.; Soutelino, Rafael G.; Ponsoni, Leandro; Klein, Daniel A., E-mail: mahiques@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Inst. Oceanografico


    The aim of this work was to generate an inventory of the data on radiocarbon dating obtained from sediments of the Sao Paulo bight (southern Brazilian upper margin) and to analyze the data in terms of Late Quaternary sedimentary processes and sedimentation rates. A total of 238 radiocarbon dating from materials collected using different sampling procedures was considered for this work. The sedimentation rates varied from less than 2 to 68 cm.kyr{sup -1}. The highest sedimentation rate values were found in a low-energy (ria type) coastal system as well as in the upwelling zones of Santa Catarina and Cabo Frio. The lowest rates were found on the outer shelf and upper slopes. Our results confirm the strong dependency of the shelf currents, with an emphasis to the terrigenous input from the Rio de La Plata outflow which is transported via the Brazilian coastal current, as well as of the coupled Brazil Current - Intermediate Western Boundary Current (BC-IWBC) dynamics on the sedimentary processes. At least three indicators of the paleo sea level were found at 12200 yr BP (conventional radiocarbon age) (103 meters below sea level - mbsl), 8300-8800 cal yr BP (13 mbsl) and 7700-8100 cal yr BP (6 mbsl). (author)

  1. Evolution of the continental margin of southern Spain and the Alboran Sea (United States)

    Dillon, William P.; Robb, James M.; Greene, H. Gary; Lucena, Juan Carlos


    Seismic reflection profiles and magnetic intensity measurements were collected across the southern continental margin of Spain and the Alboran basin between Spain and Africa. Correlation of the distinct seismic stratigraphy observed in the profiles to stratigraphic information obtained from cores at Deep Sea Drilling Project site 121 allows effective dating of tectonic events. The Alboran Sea basin occupies a zone of motion between the African and Iberian lithospheric plates that probably began to form by extension in late Miocene time (Tortonian). At the end of Miocene time (end of Messinian) profiles show that an angular unconformity was cut, and then the strata were block faulted before subsequent deposition. The erosion of the unconformity probably resulted from lowering of Mediterranean sea level by evaporation when the previous channel between the Mediterranean and Atlantic was closed. Continued extension probably caused the block faulting and, eventually the opening of the present channel to the Atlantic through the Strait of Gibraltar and the reflooding of the Mediterranean. Minor tectonic movements at the end of Calabrian time (early Pleistocene) apparently resulted in minor faulting, extensive transgression in southeastern Spain, and major changes in the sedimentary environment of the Alboran basin. Active faulting observed at five locations on seismic profiles seems to form a NNE zone of transcurrent movement across the Alboran Sea. This inferred fault trend is coincident with some bathymetric, magnetic and seismicity trends and colinear with active faults that have been mapped on-shore in Morocco and Spain. The faults were probably caused by stresses related to plate movements, and their direction was modified by inherited fractures in the lithosphere that floors the Alboran Sea.

  2. Autonomous Observations of the Upper Ocean Stratification and Velocity Fields About the Seasonally-Retreating Marginal Ice Zone (United States)


    Stratification and Velocity Fields About the Seasonally-Retreating Marginal Ice Zone John M. Toole MS 21/354 Clark Laboratory, WHOI Woods Hole, MA 02543...OBJECTIVES As a contribution to the Marginal Ice Zone DRI, this research element is designed to observe the seasonal evolution of the upper-ocean...Figure 4. Drift tracks of the 5 ITP-V systems deployed during the Marginal Ice Zone DRI program. RESULTS Analysis of the MIZ

  3. Autonomous Observations of the Upper Ocean Stratification and Velocity Field about the Seasonality Retreating Marginal Ice Zone (United States)


    stratification and velocity field about the seasonality-retreating marginal ice zone 5b. GRANT NUMBER N00014-12-1-0140 Sc. PROGRAM ELEMENT NUMBER 6...STATEMENT UNLIMITED - UNCLASSIFIED 13. SUPPLEMENTARY NOTES 14. ABSTRACT As a contribution to the Marginal Ice Zone ORI, this research element was...understanding of the Arctic air-ice-ocean system. 15. SUBJECT TERMS Arctic Ocean Air-Ice-Ocean Interaction Marginal Ice Zone 16. SECURITY

  4. Wave-Ice interaction in the Marginal Ice Zone: Toward a Wave-Ocean-Ice Coupled Modeling System (United States)


    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Wave-Ice interaction in the Marginal Ice Zone: Toward a...scattering of waves by interaction with ice in the Marginal Ice Zone (MIZ). The wave model physics developed here will later be part of an operational...10.5670/oceanog.2014.73. Liu, A.K., B. Holt, and P.W. Vachon, 1991: Wave propagation in the Marginal Ice Zone: Model predictions and comparisons

  5. Autonomous Observations of the Upper Ocean Stratification and Velocity Field about the Seasonally-Retreating Marginal Ice Zone (United States)


    stratification and velocity field about the seasonality-retreating marginal ice zone Sb. GRANT NUMBER N00014-12-1 -0140 Sc. PROGRAM ELEMENT NUMBER 6...STATEMENT UNLIMITED- UNCLASSIFIED 13. SUPPLEMENTARY NOTES 14. ABSTRACT As a contribution to the Marginal Ice Zone DRI , this research element was...understanding of the Arctic air-ice-ocean system. 15. SUBJECT TERMS Arctic Ocean Air-Ice-Ocean Interaction Marginal Ice Zone 16. SECURITY

  6. Timing of the Southern African Plateau uplift : a couple landforms-margin study of Southern Namibia (United States)

    Guillocheau, François; Dauteuil, Olivier; Baby, Guillaume; Pickford, Martin; Senut, Brigitte


    The timing of the uplift of the Southern African (or Kalahari) Plateau is debated, with four scenarios of uplift: (1) at time of rifting (Early Cretaceous), (2) during Late Cretaceous, (3) around the Eocene-Oligocene boundary and (4) during Pliocene times. This knowledge is of primary importance for a better understanding of the mantle processes at the origin of this very long wavelength structure. To answer this question, we studied the key area of the northern Orange Margin (sequence stratigraphic analysis of seismic lines and wells), offshore of the Sperrgebiet. This study is coupled with an analysis of the landforms dated with associated sediments and volcanics. (1) The first uplift of the Plateau was during Late Cretaceous times, with a first increase of siliciclastic sediments supply during Late Cenomanian (95-90 Ma) in response to the beginning of the uplift along the Indian Ocean side that propagates eastward around the Campanian (85-70 Ma). (2) Because of the humid climatic conditions prevailing since Santonian (85 Ma), most of the relief of this first plateau is removed by erosion. At the end of the planation of this topography, chemical erosion is dominant with the growth of thick lateritic profiles (55?-45 Ma). (3) A second uplift of the Plateau occurred during Late Eocene-Early Oligocene (30-40 Ma - paroxysm) and Miocene with the incision of at least three generations of pediments that shape the present-day ""Great"" Escarpment. (4) This "old" Oligocene relief is probably preserved because of the decrease of the erosion due to the climate aridification, starting at Middle Miocene times (around 15 Ma).

  7. Pegfilgrastim and Rituximab in Treating Patients With Untreated, Relapsed, or Refractory Follicular Lymphoma, Small Lymphocytic Lymphoma, or Marginal Zone Lymphoma (United States)


    Contiguous Stage II Grade 1 Follicular Lymphoma; Contiguous Stage II Grade 2 Follicular Lymphoma; Contiguous Stage II Grade 3 Follicular Lymphoma; Contiguous Stage II Marginal Zone Lymphoma; Contiguous Stage II Small Lymphocytic Lymphoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Grade 1 Follicular Lymphoma; Noncontiguous Stage II Grade 2 Follicular Lymphoma; Noncontiguous Stage II Grade 3 Follicular Lymphoma; Noncontiguous Stage II Marginal Zone Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Small Lymphocytic Lymphoma; Splenic Marginal Zone Lymphoma; Stage I Grade 1 Follicular Lymphoma; Stage I Grade 2 Follicular Lymphoma; Stage I Grade 3 Follicular Lymphoma; Stage I Marginal Zone Lymphoma; Stage I Small Lymphocytic Lymphoma; Stage III Grade 1 Follicular Lymphoma; Stage III Grade 2 Follicular Lymphoma; Stage III Grade 3 Follicular Lymphoma; Stage III Marginal Zone Lymphoma; Stage III Small Lymphocytic Lymphoma; Stage IV Grade 1 Follicular Lymphoma; Stage IV Grade 2 Follicular Lymphoma; Stage IV Grade 3 Follicular Lymphoma; Stage IV Marginal Zone Lymphoma; Stage IV Small Lymphocytic Lymphoma

  8. Paleozoic evolution of active margin basins in the southern Central Andes (northwestern Argentina and northern Chile) (United States)

    Bahlburg, H.; Breitkreuz, C.

    The geodynamic evolution of the Paleozoic continental margin of Gondwana in the region of the southern Central Andes is characterized by the westward progression of orogenic basin formation through time. The Ordovician basin in the northwest Argentinian Cordillera Oriental and Puna originated as an Early Ordovician back-arc basin. The contemporaneous magmatic arc of an east-dipping subduction zone was presumably located in northern Chile. In the back-arc basin, a ca. 3500 meter, fining-up volcaniclastic apron connected to the arc formed during the Arenigian. Increased subsidence in the late Arenigian allowed for the accomodation of large volumes of volcaniclastic turbidites during the Middle Ordovician. Subsidence and sedimentation were caused by the onset of collision between the para-autochthonous Arequipa Massif Terrane (AMT) and the South American margin at the Arenigian-Llanvirnian transition. This led to eastward thrusting of the arc complex over its back-arc basin and, consequently, to its transformation into a marine foreland basin. As a result of thrusting in the west, a flexural bulge formed in the east, leading to uplift and emergence of the Cordillera Oriental shelf during the Guandacol Event at the Arenigian-Llanvirnian transition. The basin fill was folded during the terminal collision of the AMT during the Oclóyic Orogeny (Ashgillian). The folded strata were intruded post-tectonically by the presumably Silurian granitoids of the "Faja Eruptiva de la Puna Oriental." The orogeny led to the formation of the positive area of the Arco Puneño. West of the Arco Puneño, a further marine basin developed during the Early Devonian, the eastern shelf of which occupied the area of the Cordillera Occidental, Depresión Preandina, and Precordillera. The corresponding deep marine turbidite basin was located in the region of the Cordillera de la Costa. Deposition continued until the basin fill was folded in the early Late Carboniferous Toco Orogeny. The basin

  9. Tectonic phase separation applied to the Sudetic Marginal Fault Zone (NE part of the Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Nováková, Lucie


    Roč. 12, č. 2 (2015), s. 251-267 ISSN 1672-6316 R&D Projects: GA ČR GA205/09/1244 Institutional support: RVO:67985891 Keywords : Sudetic Marginal Fault Zone * paleostress reconstruction * active tectonics * frequency analysis Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.017, year: 2015

  10. Recruitment and selection of marginal zone B cells is independent of exogenous antigens

    NARCIS (Netherlands)

    Dammers, PM; Kroese, FGM

    Marginal zone B (MZ-B) cells of the spleen contribute significantly to the immunity against invasive infections with polysaccharide-encapsulated bacteria. Recent evidence indicates that recruitment and selection of MZ-B cells occurs on the basis of positive selection constraints that likely operate

  11. lmmunohistochemical and Molecular Characterization of Extranodal Marginal Zone B-Cell Lymphoma in Salivary Glands (United States)


    in its classification to refer to a primary extranodal lymphoma composed of morphologically heterogeneous small B- cells (marginal zone cells...this review. In addition to characteristic morphologic appearance during microscopic evaluation, immunohistochemical (IHC) staining techniques...lymphocytic lymphoma/chronic lymphocytic leukemia , mantle cell lymphoma, and follicular lymphoma.40 The ten cases (59%) with κ light-chain

  12. Subduction zone processes and continental crust formation in the southern Central Andes: insights from geochemistry and geochronology


    Jones, Rosemary Ellen


    Subduction zones, such as the Andean convergent margin, are the sites at which new continental crust is generated, and where subducting material is either recycled to the crust via arc magmatism or transferred to the deep mantle. The composition of arc magmas and associated new continental crust reflects variable contributions from mantle, crustal and subducted reservoirs. Insights into crustal growth and recycling processes in the southern Central Andes, specifically in the ...

  13. Glacigenic landform features in marginal zone of Russell and Leverett glaciers, West Greenland (United States)

    Šinkūnas, Petras; Česnulevičius, Algimantas; Karmaza, Bronislavas; Baltrūnas, Valentinas


    During glacial ice melting, the sedimentation of transported material creates a variety of landforms depending on bedrock surface, glaciodynamic processes and features of sedimentation in glacial and periglacial environments in the ice marginal zone. The landforms created during sedimentation in glacial and periglacial environments are greatly dependent on the location or subenvironment of the sedimentation process, i. e. on whether it is taking place in subglacial, englacial, supraglacial, terminoglacial or proglacial subenvironments. The landform study at the marginal zone of the Russell and the Leverett glaciers in Western Greenland near Kangerlussuaq was carried out in glacial and periglacial environments. Besides morphological observations, the architecture of glacially accumulated forms was studied in outcrops. All these studies enabled to analyse the landforms in relation to glacial and periglacial facies. Marginal and proglacial forms in front of the Leverett Glacier were mapped in detail. Sedimentation of lodgement, basal, ablation and flow till deposits was observed in different subenvironments of the glacial environment in the marginal part of the glacier. These deposits in the form of till complexes in the periglacial environment were studied as landforms - lateral and end moraines formed in a terminoglacial subenvironment and basal till plains in a proglacial subenvironment left after ice retreat. Ice-cored moraines with a washboard moraine type surface of kettled topography with water ponds in kettle holes were studied in the ice divide area between the Russell and the Isunnguata glaciers. The whole complex of landforms of different origin was studied in the ice marginal zone of the Leverett Glacier, the south-western branch of the Russell Glacier. The data collected during this study indicate the importance of the climatological factors lying behind the exceptional geodiversity of the area and the glaciodynamic contribution to the richness of

  14. Miocene to Present evolution of the Calabria Tyrrhenian continental margin (Southern Tyrrhenian Sea) (United States)

    Pepe, F.; Sulli, A.; Bertotti, G.; Cella, F.


    The Miocene to Present evolution of the Calabria Tyrrhenian Continental Margin (CTCM, Southern Tyrrhenian Sea) are reconstructed using two ENE-WSW oriented, near-vertical seismic profiles (CROP-M27 and SISTER 11 lines). The interpreted profiles were time-to-depth converted, merged and translated in a geological section, which was also extended to the Tyrrhenian bathial plain and the Calabrian arc using wide-angle seismic data [Scarascia et al., 1994], and tested with gravity modelling. Across the CTCM, top of KCU is laterally variable in depth forming basins filled by Oligo-Miocene clastic to terrigenous deposits up to 1500m thick. Basins are separated by major structures with contractional or transcurrent kinematics, where faults are arranged in a positive flower structure fashion, affecting the KCU as well as lower Oligocene to Miocene deposits. The Messinian evaporites display essentially a constant thickness of ~-400m with the exception of the Paola Basin where deep-water Messinian evaporites are up to 1000 m thick. Plio-Quaternary deposits display a remarkable variation in thickness from ~-4.5 km in the Paola Basin to less then 400m in the central sector of the margin. Plio-Quaternary sediments are internally sub-divisible into four sub-units separated by tectonics enhanced angular unconformities. W-ward vergent reverse faults with limited vertical displacement offset the top of KCU as well as the Oligo-Miocene sedimentary and evaporitic units in the eastern side of the Paola basin and in the distal part of the CTCM where a number of closely spaced, W-vergent thrust faults are also observed in the Plio-Pleistocene deposits. Along the CTCM, the only significant normal fault which was identified is located around its central sector, dips to the W and has a displacement of ~-580m. Across the margin, the Moho was inferred at ~-35 km beneath the Calabria Arc and shallows up to 24 km in correspondence with the coastline. Moho deepens again to a depth of ~-28 km in

  15. Strain distribution across magmatic margins during the breakup stage: Seismicity patterns in the Afar rift zone (United States)

    Brown, C.; Ebinger, C. J.; Belachew, M.; Gregg, T.; Keir, D.; Ayele, A.; Aronovitz, A.; Campbell, E.


    Fault patterns record the strain history along passive continental margins, but geochronological constraints are, in general, too sparse to evaluate these patterns in 3D. The Afar depression in Ethiopia provides a unique setting to evaluate the time and space relations between faulting and magmatism across an incipient passive margin that formed above a mantle plume. The margin comprises a high elevation flood basalt province with thick, underplated continental crust, a narrow fault-line escarpment underlain by stretched and intruded crust, and a broad zone of highly intruded, mafic crust lying near sealevel. We analyze fault and seismicity patterns across and along the length of the Afar rift zone to determine the spatial distribution of strain during the final stages of continental breakup, and its relation to active magmatism and dike intrusions. Seismicity data include historic data and 2005-2007 data from the collaborative US-UK-Ethiopia Afar Geodynamics Project that includes the 2005-present Dabbahu rift episode. Earthquake epicenters cluster within discrete, 50 km-long magmatic segments that lack any fault linkage. Swarms also cluster along the fault-line scarp between the unstretched and highly stretched Afar rift zone; these earthquakes may signal release of stresses generated by large lateral density contrasts. We compare Coulomb static stress models with focal mechanisms and fault kinematics to discriminate between segmented magma intrusion and crank- arm models for the central Afar rift zone.

  16. Wave Climate and Wave Mixing in the Marginal Ice Zones of Arctic Seas, Observations and Modelling (United States)


    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Wave Climate and Wave Mixing in the Marginal Ice Zones of... Australia phone: +61-3-9214-8033 fax: +61-3-9214-8264 email: Ian R. Young The Australian National University Canberra, ACT 2000... Australia phone: +61-2-6125-2510 fax: +61-2-6257-3292 email: S. Zieger Swinburne University of Technology PO Box 218 (H38

  17. Crustal structure of the Gulf of Aden southern margin: Evidence from receiver functions on Socotra Island (Yemen) (United States)

    Ahmed, Abdulhakim; Leroy, Sylvie; Keir, Derek; Korostelev, Félicie; Khanbari, Khaled; Rolandone, Frédérique; Stuart, Graham; Obrebski, Mathias


    Breakup of continents in magma-poor setting occurs primarily by faulting and plate thinning. Spatial and temporal variations in these processes can be influenced by the pre-rift basement structure as well as by early syn-rift segmentation of the rift. In order to better understand crustal deformation and influence of pre-rift architecture on breakup we use receiver functions from teleseismic recordings from Socotra which is part of the subaerial Oligo-Miocene age southern margin of the Gulf of Aden. We determine variations in crustal thickness and elastic properties, from which we interpret the degree of extension related thinning and crustal composition. Our computed receiver functions show an average crustal thickness of ~ 28 km for central Socotra, which decreases westward along the margin to an average of ~ 21 km. In addition, the crust thins with proximity to the continent-ocean transition to ~ 16 km in the northwest. Assuming an initial pre-rift crustal thickness of 35 km (undeformed Arabian plate), we estimate a stretching factor in the range of ~ 2.1-2.4 beneath Socotra. Our results show considerable differences between the crustal structure of Socotra's eastern and western sides on either side of the Hadibo transfer zone; the east displays a clear intracrustal conversion phase and thick crust when compared with the western part. The majority of measurements across Socotra show Vp/Vs ratios of between 1.70 and 1.77 and are broadly consistent with the Vp/Vs values expected from the granitic and carbonate rock type exposed at the surface. Our results strongly suggest that intrusion of mafic rock is absent or minimal, providing evidence that mechanical thinning accommodated the majority of crustal extension. From our observations we interpret that the western part of Socotra corresponds to the necking zone of a classic magma-poor continental margin, while the eastern part corresponds to the proximal domain.

  18. The evolution of the southern Baltic coastal zone

    Directory of Open Access Journals (Sweden)

    Józef E. Mojski


    Full Text Available This article discusses the formation and evolution of the coastal zone of the southern Baltic from the decay of the last Scandinavian ice-sheet, which took place some 14 ka BP. During the first 4 ka, the shores of the then southern Baltic basins were shaped under the dominant influence of considerable variations in water level and the young, post-glacial topography emerging from under the ice. Later, until the beginning of the Atlantic transgression, the shores were also unstable, because sea level changes resulting from periodic connections with the World Ocean followed one another in rapid succession. Since that transgression destroyed much of the former shoreline, its reconstruction is at best highly problematical, and in some places no longer possible. The maximum range of the Litorina Sea gave rise to a coastal zone that in many places is to this day quite conspicuous in the local topography and sediments. During the last 4 ka, the shoreline has changed relatively little, thus the present shoreline is largely redolent of the original one. In the coming 100 years or so, the abrasion of the cliffs along the southern Baltic shore will probably accelerate, as will the retrogradation of certain sections of the shoreline, with the result that the shoreline will be less of a straight line than it is at present. Land up to a height of 1 m above sea level will be inundated. The greatest changes in the lie of the shoreline are to be expected in the River Wisla (Vistula delta and around the Zalew Szczecinski (Oderhaff, Szczecin Lagoon.

  19. The southern Svalbard Margin sedimentary system: preliminary results from EGLACOM cruise 2008 (United States)

    Melis, Romana; Lucchi, Renata G.; Giorgetti, Giovanna; Persico, Davide; Ángeles Bárcena, Maria; Caburlotto, Andrea; Macrı, Patrizia; Villa, Giuliana; Sagnotti, Leonardo; Rebesco, Michele


    The Storfjorden sedimentary system (South-western Svalbard margin) was investigated during the EGLACOM cruise between 8th July and 4th August 2008 on board R/V OGS-Explora. EGLACOM (Evolution of a GLacial Arctic COntinental Margin: the southern Svalbard ice stream-dominated sedimentary system) project is the Italian contribution to the International Polar Year (IPY) Activity 367 (Neogene ice streams and sedimentary processes on high-latitude continental margins - NICE STREAMS) in combination with the IPY-Spanish SVAIS project. Four EGLACOM sediment cores were collected from the slope and shelf areas and were scanned for radiographs and multi-sensor core logger for physical properties. Sediment samples were collected every 10 cm, and analyzed for textural and compositional characteristics including the biogenic components. Paleomagnetic and rock-magnetic investigations were carried out at high-resolution along the core's length. Both data sets contributed to develop a high-resolution age models in combination with the palaeostratigraphy (using foraminifera, diatoms and nannoplankton) and AMS dating. On the upper slope, coarser-grained sediments containing abundant pebbles (IRD-rich facies), overlain a sequence of laminated mud interbedded with silt layers (laminated facies), having scarce, badly preserved and often reworked biogenic fraction. On the lower slope, the uppermost sequence is formed by fine-grained bioturbated sediments with abundant planktonic and benthic foraminifera reflecting open-ocean conditions similar to present days. The dominance of the benthic foraminifera Cibicidoides wuellerstorfi indicates well oxygenated bottom waters and the calcareous nannofossil' assemblage indicates this facies deposited within the Emiliania huxleyi Acme Zone. The bioturbated facies overlay an interval of crudely laminated mud containing a peak of diatoms and sponge spiculae abundance that corresponds to a decrease in foraminifers content. Here the nannofossil

  20. Synthesis and tectonic interpretation of the westernmost Paleozoic Variscan orogen in southern Mexico: From rifted Rheic margin to active Pacific margin (United States)

    Keppie, J. Duncan; Dostal, Jaroslav; Murphy, J. Brendan; Nance, R. Damian


    origin along the southern margin of the Rheic Ocean. Latest Devonian-Permian deposition was synchronous with Mississippian extrusion of the HP rocks into the upper plate during extensional deformation. The HP Cambro-Orodivician rift-shelf rocks are inferred to have originated in the forearc region of the upper plate that was removed by subduction erosion, carried down the subduction channel, and then extruded into the upper plate in the middle of the Mixteca terrane. The presence of arc-related rocks in the HP assemblage suggests that the arc complex was also removed, whereas the MORB rocks may have been derived from the subducting slab. Detrital zircons in the Carboniferous rocks of both the Mixteca and Oaxaquia terranes contain Devonian detrital zircons and volcanic clasts that are inferred to have come from the removed Devonian arc on the western margin of the Mixteca terrane and/or from exhumed HP rocks. During the Permian, arc-related intrusions in both the Mixteca and Oaxaquia terranes were accompanied by dextral transtensional deformation and deposition of clastic rocks containing Permian detrital zircons and carbonates in periarc, pull-apart basins. Empirical relationships between the dip of the Benioff zone and the widths of arc and forearc indicate that the Permian trench lay beneath the eastern edge of the Mesozoic Guerrero terrane.

  1. A new integrated tectonic model for the Mesozoic-Early Cenozoic subduction, spreading, accretion and collision history of Tethys adjacent to the southern margin of Eurasia (NE Turkey) (United States)

    Robertson, Alastair; Parlak, Osman; Ustaömer, Timur; Taslı, Kemal; İnan, Nurdan; Dumitrica, Paulian; Karaoǧlan, Fatih


    A major Tethyan suture zone (İzmir-Ankara-Erzincan-Kars Suture Zone) borders the southern margin of Eurasia throughout the Pontides. In eastern Turkey the suture zone includes a range of redeposited terrigenous and volcanogenic sedimentary rocks, pelagic sedimentary rocks and also igneous/metamorphic rocks. The igneous rocks are mostly basaltic blocks and thrust sheets within melange, plus relatively intact, to dismembered, ophiolitic rocks (oceanic crust). Two alternative hypotheses have been developed and tested during this work: 1. The suture zone preserves a single Andean-type active continental margin associated with northward subduction, accretion and arc magmatism during Mesozoic-early Cenozoic time; 2. The suture zone preserves the remnants of two different subduction zones, namely a continental margin subduction zone (as above) and an intra-ocean subduction zone (preferred model). To determine the age of the oceanic crust, relevant to both hypotheses, zircons were extracted from basic ophiolitic rocks (both intact and dismembered) and dated by the U/Pb method (U238/U236) using an ion probe at Edinburgh University. This yielded the following results for the intact ophiolites (Ma): plagiogranite cutting sheeted dykes of the Refahiye ophiolite (east of Erzincan), 183.6±1.7 (2σ); isotropic gabbro from the Karadaǧ ophiolite (northeast of Erzurum), 179.4±1.7 (2σ). In addition, dismembered ophiolites gave the following ages: gabbro cumulate (Bayburt area), 186.2±1.4 (2σ), gabbro cumulate (N of Horasan), 178.1±1.8 (2σ). Furthermore, two samples from a kilometre-sized (arc-related) tonalite body, mapped as cutting a thrust sheet of ophiolitic isotropic gabbro in the Kırdaǧ area, yielded ages of 182.1±3.2 (2σ) and 185.1±3.0 (2σ) Ma. We infer that the ophiolitic and related magmatic arc rocks formed by spreading in a supra-subduction zone setting during the late Early Jurassic (Pliensbachian-Toarcian). This amends former assumptions of a Late

  2. Structural style and tectonic evolution of the easternmost Gulf of Aden conjugate margins (Socotra - Southern Oman) (United States)

    Nonn, Chloe; Leroy, Sylvie; Castilla, Raymi; de Clarens, Philippe; Lescanne, Marc


    Observations from distal rifted margins in present day magma-poor rifted margins led to the discovery of hyperextended crust and exhumed sub-continental mantle. This finding allowed to better figure out how thinning process are accommodate by tectonic structures, forming various crustal domains, as the deformation localized towards the future area of breakup. However, some of the current challenges are about clarifying how factors as oblique kinematic, pre-existing structures and volcanism can control the 3D geometry and crustal architecture of the passive margins? A key to better understand the rifting evolution in its entirety is to study conjugate margins. The gulf of Aden is a young oceanic basin (with a global trend about N75°E) oblique to the divergence (about 30°N), separating Arabia from Somalia of less than 800 km. Thanks to its immerged margins and its thin post-rift sediment cover, the gulf of Aden basin is a natural laboratory to investigate conjugate margins and strain localisation throughout the rift history. In this contribution, we focus our interest on offshore Socotra Island (Yemen) and its conjugate in Southeastern Oman. This area extends from Socotra-Hadbeen (SHFZ) and the eastern Gulf of Aden fault zones (EGAFZ). In the easternmost part of the gulf of Aden, we provide new insights into crustal deformation and emplacement of the new oceanic crust thanks to bathymetric, magnetic, gravimetric data and single-, multi-channel, high speed seismic reflection data collected during Encens-Sheba (2000), Encens (2006) and the more recent Marges-Aden (2012) cruises respectively. The results obtained after compilation of these data, previous geological (field works) and geophysical (receiver functions, Pn-tomography, magnetic anomalies, heat flow) studies on the focused area, allowed us to provide new structural mapping and stratigraphic correlation between onshore and offshore parts of Socotra and Oman margins. We precisely defined and map crustal

  3. Apoptotic cell responses in the splenic marginal zone: A paradigm for immunologic reactions to apoptotic antigens with implications for autoimmunity (United States)

    McGaha, Tracy L.; Karlsson, Mikael C.I.


    Summary Apoptotic cells drive innate regulatory responses that result in tolerogenic immunity. This is a critical aspect of cell physiology as apoptotic cells expose potentially dangerous nuclear antigens on the surface in apoptotic blebs, and failure in their recognition, phagocytosis, or destruction can cause dramatic autoimmunity in experimental models and is linked to development and progression of systemic pathology in man. The marginal zone is a specialized splenic environment that serves as a transitional site from circulation to peripheral lymphoid structures. The marginal zone serves a key role in trapping of particulates and initiation of innate responses against systemic microbial pathogens. However in recent years it has become clear the marginal zone is also important for initiation of immune tolerance to apoptotic cells, driving a coordinated response involving multiple phagocyte and lymphocyte subsets. Recent reports linking defects in splenic macrophage function to SLE in a manner analogous to marginal zone macrophages in lupus-prone mice provides an impetus to better understand the mechanistic basis of the apoptotic cell response in the marginal zone and its general applicability to apoptotic cell-driven tolerance at other tissue sites. In this review we discuss immune responses to apoptotic cells in the spleen in general and the marginal zone in particular, the relationship of these responses to autoimmune disease, and comparisons to apoptotic cell immunity in humans. PMID:26683143

  4. A Regional View of the Margin: Salmonid Abundance and Distribution in the Southern Appalachian Mountains of North Carolina and Virginia (United States)

    Patricia A. Flebbe


    In the southern Appalachian Mountains, native brook trout Salvelinus fontinalis and introduced rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta are at the southern extremes of their distributions, an often overlooked kind of marginal habitat. At a regional scale composed of the states of Virginia...


    Directory of Open Access Journals (Sweden)



    Full Text Available The Guadalquivir foreland basin, located between the Iberian basement northward and the Betic orogen to the South, represents the western sector of the earlier foredeep basin of the Betic Cordillera. Along the northern foreland margin, the sedimentary fill of this basin includes a Tortonian Basal Transgressive Complex (BTC, composed of five internal sequences bounded by transgressive surfaces. Two main parts are distinguished within each sequence: the lower transgressive lag deposits, and the upper stillstand/prograding sediments. Three facies associations were distinguished within this stratigraphic succession along the central sector of this basin margin: unfossiliferous conglomerates and coarse-grained sands (A, fossiliferous conglomerates and coarse-grained sands (B, and yellow medium-coarse-grained fossiliferous sands (C. A fourth facies association (D: blue silty marlstones and shales overlies the BTC. Deposits of alluvial sediments (facies association A and shallow-marine/foreshore sediments (facies association C, were recurrently interrupted by transgressive pulses (facies associations B and C. Every pulse is recorded by an erosional, cemented sandy-conglomerate bar with bivalves (Ostreidae, Isognomon, balanids, gastropods and other marine bioclasts; or their transgressive equivalents. The lateral facies changes in each individual sequence of the BTC are related to: (1 the influence on the northern foreland margin of the tectonic activity of the southern orogenic margin; (2 the palaeorelief formed by irregularities of the substrate which controls the sediment dispersal; and (3 the evolution stages of the sedimentary systems. 

  6. Extranodal marginal zone lymphoma in the ocular region: clinical, immunophenotypical, and cytogenetical characteristics

    DEFF Research Database (Denmark)

    Sjö, Lene D; Heegaard, Steffen; Prause, Jan U


    the period 1980 to 2005 were reviewed and reclassified according to the World Health Organization (WHO) classification. Cases reclassified as EMZL were selected and reviewed with respect to clinical characteristics and outcome. The presence of translocations involving IGH and/or MALT1 was investigated in 42......PURPOSE: To evaluate clinical, immunophenotypical, and cytogenetical characteristics of 116 patients with a diagnosis of extranodal marginal zone lymphoma (EMZL) presenting primarily in the ocular region. METHODS: Specimens from all patients with a diagnosis of ophthalmic lymphoma in Denmark during...

  7. Interference from lupus anticoagulant on von Willebrand factor measurement in splenic marginal zone lymphoma

    DEFF Research Database (Denmark)

    Vinholt, Pernille J; Nybo, Mads


    We present a case concerning a patient with splenic marginal zone lymphoma (SMZL) and isolated prolonged activated partial thromboplastin time (aPTT) caused by lupus anticoagulant. Von Willebrand factor (VWF) activity and antigen were immeasurable by latex particle immunoturbidimetric assays......, and several coagulation factor levels were decreased. However, VWF activity and antigen were normal when analyzed by other methods. Also, coagulation factor levels were normal if an aPTT reagent with low lupus anticoagulant sensitivity or a chromogenic method was applied. Altogether, the initial findings were...

  8. An Early Cretaceous volcanic arc/marginal basin transition zone, Peninsula hardy, southernmost Chile (United States)

    Miller, Christopher A.; Barton, Michael; Hanson, Richard E.; Fleming, Thomas H.


    The Hardy Formation represents a latest Jurassic-Early Cretaceous volcanic arc that was located along the Pacific margin of southern South America. It was separated from the continent by a marginal basin floored by portions of an ophiolite sequence (the Rocas Verdes ophiolites). The transition between the arc and marginal basin occurs on Peninsula Hardy, southernmost Chile, where there is a lateral facies transition from arc deposits of the Hardy Formation into proximal marginal basin fill of the Yahgan Formation. Interfingering of arc and marginal basin sequences demonstrates that subduction-related arc magmatism was concurrent with marginal basin formation. The lateral facies transition is reflected in the geochemistry of volcanic rocks from the Hardy and Yahgan formations. Basalts, andesites and dacites of the arc sequence follow a calc-alkaline differentiation trend whereas basalts from the marginal basin follow a tholeiitic differentiation trend. Estimates of temperature and oxygen fugacity for crystallization of the arc andesites are similar to values reported for other calc-alkaline andesites. It is suggested that water activity influenced the early or late crystallization of Ti-magnetite and this controlled the style of differentiation of the magmas erupted on Peninsula Hardy. Magmas with high water contents evolved along the calc-alkaline differentiation trend whereas those with low water contents evolved along the tholeiitic differentiation trend. Some rhyolites are differentiated from the calc-alkaline andesites and dacites, but most appear to be the products of crustal anatexis on the basis of trace-element evidence. The arc basalts and some marginal basin basalts show relative enrichment in LILE, relative depletion in HFSE, and enrichment in LREE. Other marginal basin basalts are LREE depleted and show small relative depletions in HFSE. Basalts with both calc-alkaline and tholeiitic affinities can also be recognized in the Rocas Verdes ophiolites

  9. 76 FR 34859 - Safety Zone; Augusta Southern Nationals Drag Boat Race, Savannah River, Augusta, GA (United States)


    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Augusta Southern Nationals Drag Boat Race... during the Augusta Southern Nationals Drag Boat Race. The Augusta Southern Nationals Drag Boat Race will consist of a series of high-speed boat races. The event is scheduled to take place from Thursday, July 14...

  10. Tsunami Hazard Posed to New Zealand by the Kermadec and Southern New Hebrides Subduction Margins: An Assessment Based on Plate Boundary Kinematics, Interseismic Coupling, and Historical Seismicity (United States)

    Power, William; Wallace, Laura; Wang, Xiaoming; Reyners, Martin


    We assess the tsunami hazard posed to New Zealand by the Kermadec and southern New Hebrides subduction margins. Neither of these subduction zones has produced tsunami large enough to cause significant damage in New Zealand over the past 150 years of well-recorded history. However, as this time frame is short compared to the recurrence interval for major tsunamigenic earthquakes on many of the Earth's subduction zones, it should not be assumed that what has been observed so far is representative of the long term. For each of these two subduction zones we present plate kinematic and fault-locking results from block modelling of earthquake slip vector data and GPS velocities. The results are used to estimate the current rates of strain accumulation on the plate interfaces where large tsunamigenic earthquakes typically occur. We also review data on the larger historical earthquakes that have occurred on these margins, as well as the Global CMT catalogue of events since 1976. Using this information we have developed a set of scenarios for large earthquakes which have been used as initial conditions for the COMCOT tsunami code to estimate the subsequent tsunami propagation in the southwest Pacific, and from these the potential impact on New Zealand has been evaluated. Our results demonstrate that there is a significant threat posed to the Northland and Coromandel regions of New Zealand should a large earthquake ( M w ≳8.5) occur on the southern or middle regions of the Kermadec Trench, and that a similarly large earthquake on the southern New Hebrides Trench has the potential to strongly impact on the far northern parts of New Zealand close to the southern end of the submarine Three Kings Ridge. We propose logic trees for the magnitude-frequency parameters of large earthquakes originating on each trench, which are intended to form the basis for future probabilistic studies.

  11. Meso- and submesoscale structures in marginal ice zone in Arctic ocean using Sentinel-1 data (United States)

    Tarasenko, Anastasiia


    A marginal sea ice zone is a region where ocean currents interact with the sea ice. Recently freezed small sea ice particles (frazil) can be used as a passive tracer for the ocean surface dynamics studies. Sentinel-1 SAR images with a high spatial resolution (40 or 25 m) permit to exploit this approach of "frazil as surface current's passive tracer". A preliminary research on meso- and submesoscale structures in marginal sea ice zone was carried out using Sentinel-1 SAR data. A new dataset of mesoscale structures was created for Eastern Greenland, Barents and Kara seas for 2014-2015. The raw data was processed with SNAP (Sentinel application Platform designed by ESA). A classical method of maximum cross-correlation was tested together with a method developed based on (Kudriavtsev et al, 2014) for eddy-like structures detection. References: Kudryavtsev, Vladimir, I. Kozlov, Bertrand Chapron, and J. A. Johannessen. "Quad-polarization SAR features of ocean currents." Journal of Geophysical Research: Oceans 119, no. 9 (2014): 6046-6065.

  12. Stereotyped patterns of B-cell receptor in splenic marginal zone lymphoma

    KAUST Repository

    Zibellini, S.


    Antigen stimulation may be important for splenic marginal zone lymphoma pathogenesis. To address this hypothesis, the occurrence of stereotyped B-cell receptors was investigated in 133 SMZL (26 HCV+) compared with 4,414 HCDR3 sequences from public databases. Sixteen SMZL (12%) showed stereotyped BCR; 7 of 86 (8%) SMZL sequences retrieved from public databases also belonged to stereotyped HCDR3 subsets. Three categories of subsets were identified: i) SMZL-specific subsets (n=5), composed only of 12 SMZL (9 HCV- from our series); ii) Non-Hodgkin\\'s lymphoma-like subsets (n=5), comprising 5 SMZL (4 from our series) clustering with other indolent lymphomas; iii) "CLL-like subsets" (n=6), comprising 6 SMZL (3 from our series) that belonged to known CLL subsets (n=4) or clustered with public CLL sequences. Immunoglobulin 3D modeling of 3 subsets revealed similarities in antigen binding regions not limited to HCDR3. Overall, data suggest that the pathogenesis of splenic marginal zone lymphoma may involve also HCV unrelated epitopes or an antigenic trigger common to other indolent lymphomas. ©2010 Ferrata Storti Foundation.

  13. Energy-conserving perennial agriculture for marginal land in southern Appalachia. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.


    USDA economists predict the end of surplus farm production in the US within this decade. More and more marginal land will be cropped to provide feed for the growing world population and to produce energy. Much of this potential cropland in Southern Appalachia is poorly suited to annual crops, such as corn. Perennial crops are much better suited to steep, rocky, and wet sites. Research was undertaken on the theoretical potentials of perennial species with high predicted yields of protein, carbohydrates, or oils. Several candidate staple perennial crops for marginal land in Southern Appalachia were identified, and estimates were made of their yields, energy input requirements, and general suitabilities. Cropping systems incorporating honeylocust, persimmon, mulberry, jujube, and beech were compared with corn cropping systems. It appears that these candidate staple perennials show distinct advantages for energy conservation and environmental preservation. Detailed economic analyses must await actual demonstration trials, but preliminary indications for ethanol conversion systems with honeylocust are encouraging. It is suggested that short-term loans to farmers undertaking this new type of agriculture would be appropriate to solve cash-flow problems.

  14. Comparative analysis of glucagonergic cells, glia and the circumferential marginal zone in the reptilian retina (United States)

    Todd, Levi; Suarez, Lilianna; Squires, Natalie; Zelinka, Christopher Paul; Gribbins, Kevin; Fischer, Andy J.


    Retinal progenitors in the circumferential margin zone (CMZ) and Müller glia-derived progenitors have been well-described in the eyes of fish, amphibians and birds. However, there is no information regarding a CMZ and the nature of retinal glia in species phylogenetically bridging amphibians and birds. Thus, the purpose of this study was to examine the retinal glia and investigate whether a CMZ is present in the eyes of reptilian species. We used immuno-histochemical analyses to study retinal glia, neurons that could influence CMZ-progenitors, the retinal margin, and non-pigmented epithelium (NPE) of ciliary body of garter snakes, queen snakes, anole lizards, snapping turtles, and painted turtles. We compare our observations in reptile eyes to the CMZ and glia of fish, amphibians and birds. In all species, Sox9, Pax6 and the glucocorticoid receptor are expressed by Müller glia and cells at the retinal margin. However, proliferating cells were found only in the CMZ of turtles, but not in the eyes of anoles and snakes. Similar to eyes of chickens, the retinal margin in turtles contains accumulations of GLP1/glucagonergic neurites. We find that filamentous proteins, vimentin and GFAP, are expressed by Müller glia, but have different patterns of sub-cellular localization in the different species of reptiles. We provide evidence that the reptile retina may contain Non-astrocytic Inner Retinal Glial (NIRG) cells, similar to those described in the avian retina. We conclude that the retinal glia, glucagonergic neurons and CMZ of turtles appears to be the most similar to that of fish, amphibians and birds. PMID:26053997

  15. Hydraulic structure of a fault zone at seismogenic depths (Gole Larghe Fault Zone, Italian Southern Alps) (United States)

    Bistacchi, Andrea; Mittempergher, Silvia; Di Toro, Giulio; Smith, Steve; Garofalo, Paolo; Vho, Alice


    The Gole Larghe Fault Zone (GLFZ, Italian Southern Alps) was exhumed from c. 8 km depth, where it was characterized by seismic activity (pseudotachylytes), but also by hydrous fluid flow (alteration halos and precipitation of hydrothermal minerals in veins and cataclasites). Thanks to glacier-polished outcrops exposing the fault zone over a continuous area > 1 km2, the fault zone architecture has been quantitatively described with an unprecedented detail (Bistacchi 2011, PAGEOPH; Smith 2013, JSG; Mittempergher 2016, this meeting), providing a rich dataset to generate 3D Discrete Fracture Network (DFN) models and simulate the fault zone hydraulic properties. Based on field and microstructural evidence, we infer that the opening and closing of fractures resulted in a toggle-switch mechanism for fluid flow during the seismic cycle: higher permeability was obtained in the syn- to early post-seismic period, when the largest number of fractures was (re)opened by off-fault deformation, then permeability dropped due to hydrothermal mineral precipitation and fracture sealing. Since the fracture network that we observe now in the field is the result of the cumulative deformation history of the fault zone, which probably includes thousands of earthquakes, a fundamental parameter that cannot be directly evaluated in the field is the fraction of fractures-faults that were open immediately after a single earthquake. Postseismic permeability has been evaluated in a few cases in the world thanks to seismological evidences of fluid migration along active fault systems. Therefore, we were able to develop a parametric hydraulic model of the GLFZ and calibrate it, varying the fraction of faults/fractures that were open in the postseismic period, to obtain on one side realistic fluid flow and permeability values, and on the other side a flow pattern consistent with the observed alteration/mineralization pattern. The fraction of open fractures is very close to the percolation threshold

  16. Rainfall reductions over Southern Hemisphere semi-arid regions: the role of subtropical dry zone expansion. (United States)

    Cai, Wenju; Cowan, Tim; Thatcher, Marcus


    Since the late 1970s, Southern Hemisphere semi-arid regions such as southern-coastal Chile, southern Africa, and southeastern Australia have experienced a drying trend in austral autumn, predominantly during April and May. The rainfall reduction coincides with a poleward expansion of the tropical belt and subtropical dry zone by around 2°-3° in the same season. This has raised questions as to whether the regional rainfall reductions are attributable to this poleward expansion. Here we show that the impact of the poleward subtropical dry-zone shift is not longitudinally uniform: a clear shift occurs south of Africa and across southern Australia, but there is no evidence of a poleward shift in the southern Chilean sector. As such, a poleward shift of climatological April-May rainfall can explain most of the southeastern Australia rainfall decline, a small portion of the southern Africa rainfall trend, but not the autumn drying over southern Chile.

  17. A Novel del(20q) in Aggressive Nodal Marginal Zone Lymphoma (United States)

    Kern, Jason B.; Duff, Deiter J.; Odem, Jamie L.; Esebua, Magda; Smith, Lisa R.; Doll, Donald; Wang, Michael


    This is a case report of a previously undescribed 20q chromosomal deletion (del(20q)) in marginal zone lymphoma (MZL). A 54-year-old Caucasian male presented with an enlarging neck mass and multiple violaceous skin nodules over his chest. Biopsy of the neck mass and cervical lymph nodes revealed MZL. Cytogenetic evaluation of both lymph node and bone marrow tissue revealed del(20q). This was an unexpected finding, as del(20q) is associated with myelodysplastic syndromes and myeloproliferative neoplasms and rarely seen in diffuse large B-cell lymphoma, follicular lymphoma, and T-cell lymphoma, but has not previously been described in MZL. We describe the case presentation and histologic findings and discuss the significance of this novel finding. PMID:23476863

  18. A Novel del(20q in Aggressive Nodal Marginal Zone Lymphoma

    Directory of Open Access Journals (Sweden)

    Jason B. Kern


    Full Text Available This is a case report of a previously undescribed 20q chromosomal deletion (del(20q in marginal zone lymphoma (MZL. A 54-year-old Caucasian male presented with an enlarging neck mass and multiple violaceous skin nodules over his chest. Biopsy of the neck mass and cervical lymph nodes revealed MZL. Cytogenetic evaluation of both lymph node and bone marrow tissue revealed del(20q. This was an unexpected finding, as del(20q is associated with myelodysplastic syndromes and myeloproliferative neoplasms and rarely seen in diffuse large B-cell lymphoma, follicular lymphoma, and T-cell lymphoma, but has not previously been described in MZL. We describe the case presentation and histologic findings and discuss the significance of this novel finding.

  19. Seroprevalence and sociocultural conditionants of Chagas disease in school aged children of marginal zones of Asunción

    Directory of Open Access Journals (Sweden)

    Vera Ninfa I.


    Full Text Available Chagas disease is becoming a public health problem in Latin America due to the wide distribution, the high prevalence, the magnitude of the damage caused and the difficulties to control it. In Paraguay, the disease is mainly distributed in the departments of Paraguari, Cordillera and Central. Prevalence in marginal zones, where migrations from rural populations and endemic areas make possible the urbanization of the disease, has no been studied yet. This is a descriptive study with a cross-sectional sampling and a probabilistic system recruitment carried out in school aged children from marginal zones of Asuncion to determine the prevalence of Chagas' disease. Serological methods, parasite isolation and questionnaires were used to achieve the goals. Nine hundred and fifty three children were studied to determine the prevalence of Chagas' disease in marginal zones which was 1.4%.

  20. The Floe Size Distribution in the Marginal Ice Zone of the Beaufort and Chukchi Seas (United States)

    Schweiger, A. J. B.; Stern, H. L., III; Stark, M.; Zhang, J.; Steele, M.; Hwang, P. B.


    Several key processes in the Marginal Ice Zone (MIZ) of the Arctic Ocean are related to the size of the ice floes, whose diameters range from meters to tens of kilometers. The floe size distribution (FSD) influences the mechanical properties of the ice cover, air-sea momentum and heat transfer, lateral melting, and light penetration. However, no existing sea-ice/ocean models currently simulate the FSD in the MIZ. Model development depends on observations of the FSD for parameterization, calibration, and validation. To support the development and implementation of the FSD in the Marginal Ice Zone Modeling and Assimilation System (MIZMAS), we have analyzed the FSD in the Beaufort and Chukchi seas using multiple sources of satellite imagery: NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua satellites (250 m pixel size), the USGS Landsat 8 satellite (80 m pixel size), the Canadian Space Agency's synthetic aperture radar (SAR) on RADARSAT (50 meter pixel size), and declassified National Technical Means imagery from the Global Fiducials Library (GFL) of the USGS (1 m pixel size). The procedure for identifying ice floes in the imagery begins with manually delineating cloud-free regions (if necessary). A threshold is then chosen to separate ice from water. Morphological operations and other semi-automated techniques are used to identify individual floes, whose properties are then easily calculated. We use the mean caliper diameter as the measure of floe size. The FSD is adequately described by a power-law in which the exponent characterizes the relative number of large and small floes. Changes in the exponent over time and space reflect changes in physical processes in the MIZ, such as sea-ice deformation, fracturing, and melting. We report results of FSD analysis for the spring and summer of 2013 and 2014, and show how the FSD will be incorporated into the MIZMAS model.

  1. Velocity structure of the mantle transition zone beneath the southeastern margin of the Tibetan Plateau (United States)

    Li, Guohui; Bai, Ling; Zhou, Yuanze; Wang, Xiaoran; Cui, Qinghui


    P-wave triplications related to the 410 km discontinuity (the 410) were clearly observed from the vertical component seismograms of three intermediate-depth earthquakes that occurred in the Indo-Burma Subduction Zone (IBSZ) and were recorded by the Chinese Digital Seismic Network (CDSN). By matching the observed P-wave triplications with synthetics through a grid search, we obtained the best-fit models for four azimuthal profiles (I-IV from north to south) to constrain the P-wave velocity structure near the 410 beneath the southeastern margin of the Tibetan Plateau (TP). A ubiquitous low-velocity layer (LVL) resides atop the mantle transition zone (MTZ). The LVL is 25 to 40 km thick, with a P-wave velocity decrement ranging from approximately - 5.3% to - 3.6% related to the standard Earth model IASP91. An abrupt transition in the velocity decrement of the LVL was observed between profiles II and III. We postulate that the mantle structure beneath the southeastern margin of the TP is primarily controlled by the southeastern extrusion of the TP to the north combined with the eastward subduction of the Indian plate to the south, but not affected by the Emeishan mantle plume. We attribute the LVL to the partial melting induced by water and/or other volatiles released from the subducted Indian plate and the stagnant Pacific plate, but not from the upwelling or the remnants of the Emeishan mantle plume. A high-velocity anomaly ranging from approximately 1.0% to 1.5% was also detected at a depth of 542 to 600 km, providing additional evidence for the remnants of the subducted Pacific plate within the MTZ.

  2. A Comparison of Radiation Budgets in the Fram Strait Summer Marginal Ice Zone. (United States)

    Francis, Jennifer A.; Ackerman, Thomas P.; Katsaros, Kristina B.; Lind, Richard J.; Davidson, Kenneth L.


    Measurements of surface radiation fluxes and meteorological conditions collected in the Fram Strait during the summer 1984 Marginal Ice Zone Experiment (MIZEX) are presented and analyzed. These data were combined with calculations from a radiative transfer model to estimate surface and atmospheric moan radiation budgets on a daily basis and for the early summer season over both sea ice and open water in the marginal ice zone (MIZ). Intensities of solar and infrared fluxes within the atmospheric column, radiative properties of Arctic stratus, and atmospheric cooling rates due to the net loss of radiation were computed by the model.Results show significant differences between the radiation budgets of sea-ice and open-water regimes in the MIZ. Fluxes averaged over the experimental period (16 June to 10 July) indicate that the atmosphere-open water system gained approximately 60 W m2, while the atmosphere-ice regime was nearly in equilibrium. The open water absorbed twice as much radiation as did the ice, and the mean cooling rate of the over-water atmosphere was approximately 15% larger than that over ice. Observations and model calculations agree that the effect of varying surface albedo on flux intensities is significantly reduced in overcast conditions as compared to under clear skies.Fluxes and atmospheric cooling rates were compared to values computed by other investigators. Few studies of Arctic radiation exist due to the dearth of observations from polar regions, but available values compare well with those derived from MIZEX data. Cooling rates calculated for the Farm Strait MIZ are twice as large as estimates for the central Arctic in summer. Evidence suggests that this cooling may be offset by a relatively strong poleward atmospheric advection of sensible and latent heat from the Norwegian Sea area.

  3. Prospecting for oil formations along the marginal zone of the Aznayevskiy trough

    Energy Technology Data Exchange (ETDEWEB)

    Samoylov, V.A.; Danilova, A.P.


    Data are obtained which make it possible to outline areas on which new oil accumulations can be discovered. It has been proven that the Satayevskiy field is restricted by two graben-formed troughs, from the northwest Sergeyevsko-Demskiy, and from the southeast by the Aznayevskiy. Industrial influxes of oil have been obtained in well 224-Zildyarovo, 120-Satayvo and others in bed D-1 of the Pashiyskiy level. These formations are screened by the Aznayevskiy trough. Wells have established only their marginal parts. It is proposed that prospecting be accelerated for new formations of oil along the southeast marginal zone in the Aznayevskiy trough, especially in the area between wells 3-Zildyarovo and 18-Satayevo extending 9 km. The Satayevskiy field is divided by cross disorders into blocks which explains the presence in the fields of different water-oil contacts in bed D-1. Along the southeast edge of the Aznayevskiy trough, one should expect similar tectonic blocks, in whose limits the formations will have different water-oil contacts. Here autonomy of four oil formations is predicted which have different water-oil contacts. In order to confirm the detected formations in evaluating reserves, it is necessary to drill 3 wells at the apexes of the detected lower Permian elevations, where bed D-1 possibly is completely oil-saturated.

  4. The Cambrian-Ordovician rocks of Sonora, Mexico, and southern Arizona, southwestern margin of North America (Laurentia): chapter 35 (United States)

    Page, William R.; Harris, Alta C.; Repetski, John E.; Derby, James R.; Fritz, R.D.; Longacre, S.A.; Morgan, W.A.; Sternbach, C.A.


    Cambrian and Ordovician shelf, platform, and basin rocks are present in Sonora, Mexico, and southern Arizona and were deposited on the southwestern continental margin of North America (Laurentia). Cambrian and Ordovician rocks in Sonora, Mexico, are mostly exposed in scattered outcrops in the northern half of the state. Their discontinuous nature results from extensive Quaternary and Tertiary surficial cover, from Tertiary and Mesozoic granitic batholiths in western Sonora, and from widespread Tertiary volcanic deposits in the Sierra Madre Occidental in eastern Sonora. Cambrian and Ordovician shelf rocks were deposited as part of the the southern miogeocline on the southwestern continental margin of North America.

  5. Paleomagnetic correlation of ignimbrites along the southern margin of the central Snake River Plain, Yellowstone hotspot (United States)

    Finn, D. R.; Coe, R. S.; Spinardi, F.; Reichow, M. K.; Knott, T.; McDonnell, L.; Cunningham, D.; Branney, M.


    Mid-late Miocene explosive volcanism associated with the Yellowstone hotspot occurred in the central Snake River Plain, for example at the 12.5-11.3 Ma Bruneau-Jarbidge and 10-8.6 Ma Twin Falls eruptive centres. The volcanism was characterized by high-temperature rhyolitic caldera-forming super-eruptions, some exceeding 450 km3. To determine the number and scales and of these giant eruptions we are investigating successions of outflow ignimbrites at the southern and northern margins of the plain. The ignimbrites are exposed discontinuously in widely spaced (50-200 km) mountain ranges and are typically extensive, intensely welded and rheomorphic. Paleomagnetic characterization of individual (paleosol-bounded) eruption-units together with field, petrographic and chemical characterization will aid in stratigraphic correlation between distant sections. By correlating and mapping the eruption-units we can better estimate how the frequencies and volumes of the super-eruptions changed during eastward progression of Yellowstone hotspot volcanism. This information helps distinguish between effects of thermal flux, crustal structure, and tectonics on magmatic history of this continental large igneous province. Additionally, large caldera collapse events dramatically modify landscapes, and location and scale of calderas may have significantly contributed to Snake River Plain topography. Over 300 paleomagnetic cores were collected in September 2010 from the Cassia Hills, Rogerson Graben, and Bruneau-Jarbidge regions in the southern margin of the Snake River Plain. We drilled 10 oriented cores per eruption unit at reference sections from each location and demagnetized them with alternating-field (AF) and thermal demagnetization techniques. In some cases AF treatment up to 200 mT was unable to completely destroy a specimen's natural remnant magnetization and so thermal treatment was used to finish the experiment. Zjiderveld diagrams from AF, thermal and hybrid experiments show

  6. Are subduction zones invading the atlantic? Evidence from the southwest iberia margin

    NARCIS (Netherlands)

    Duarte, João C.; Rosas, Filipe M.; Terrinha, Pedro; Schellart, Wouter P.; Boutelier, David; Gutscher, Marc André; Ribeiro, António

    Subduction initiation at passive margins plays a central role in the plate tectonics theory. However, the process by which a passive margin becomes active is not well understood. In this paper we use the southwest Iberia margin (SIM) in the Atlantic Ocean to study the process of passive margin

  7. Epi-benthic megafaunal zonation across an oxygen minimum zone at the Indian continental margin (United States)

    Hunter, William R.; Oguri, Kazumasa; Kitazato, Hiroshi; Ansari, Zakir A.; Witte, Ursula


    The Arabian Sea oxygen minimum zone (OMZ) impinges upon the Indian continental margin at bathyal depths (150-1500 m) producing changes in ambient oxygen availability and sediment geochemistry across the seafloor. The influence of these environmental changes upon the epi-benthic megafaunal assemblage was investigated by video survey at six stations spanning the OMZ core (540 m), lower boundary (800-1100 m) and below the OMZ (2000 m), between September and November 2008. Structural changes in the megafaunal assemblage were observed across the six stations, through changes in both megafaunal abundance and lebensspuren (biogenic traces). Most megafauna were absent in the OMZ core (540 m), where the assemblage was characterised by low densities of fishes (0.02-0.03 m -2). In the lower OMZ boundary, megafaunal abundance peaked at 800 m, where higher densities of ophiuroids (0.20-0.44 m -2) and decapods (0.11-0.15 m -2) were present. Total abundance declined with depth between 800 and 2000 m, as the number of taxa increased. Changes in the megafaunal assemblage were predicted by changes in abundance of seven taxonomic groups, correlated to both oxygen availability and sediment organic matter quality. Lebensspuren densities were highest in the OMZ boundary (800-1100 m) but traces of large infauna (e.g., echiurans and enteropneusts) were only observed between 1100 and 2000 m station, where the influence of the OMZ was reduced. Thus, changes in the megafaunal assemblage across the Indian margin OMZ reflect the responses of specific taxa to food availability and oxygen limitation.

  8. Wave-Ice Interaction in the Marginal Ice Zone: Toward a Wave-Ocean-Ice Coupled Modeling System (United States)


    Wave- ice the Marginal Ice Zone: toward a wave-ocean- ice coupled modeling system W. E. Rogers Naval Research Laboratory, Code 7322, Stennis Space Center...Mississippi, Stennis Space Center, MS Now at: COEST, Swinburne Univ. Tech., Melbourne , Australia Phone: +61 3 9214 5430 email: szieger

  9. Extranodal marginal zone non Hodgkin's lymphoma of the lung: A ten-year experience

    Directory of Open Access Journals (Sweden)

    Milošević Violeta


    Full Text Available Background/Aim. Bronchus-associated lymphoid tissue (BALT lymphoma is a rare subtype of low grade marginal zone B cell lymphoma representing 10% of all MALT lymphomas. The purpose of this study was to analyze the outcome of this group of patients comparing prognostic parameters and therapy modalities. Methods. A total of eight patients with BALT lymphoma had diagnosed between January 1998 - April 2008 at the Institute of Hematology, Clinical Center of Serbia, Belgrade, and they were included in this retrospective analysis. Results. Male/female ratio was 2/6, the median age was 64 years (range 37-67 years. Six patients had nonspecific respiratory symptoms and all of them had B symptoms. The patients were seronegative for HIV, HCV and HBsAg. Three patients had Sjogren's syndrome, rheumatoid arthritis and pulmonary tuberculosis, respectively. Seven patients were diagnosed by transbronchial biopsy and an open lung biopsy was done in one patient. Patohistological findings revealed lymphoma of marginal zone B cell lymphoma: CD20+/CD10-/CD5-/CyclinD1- /CD23-/IgM- with Ki-67+<20% of all cells. According to the Ferraro staging system, five patients had localized disease (CS I-IIE and three had stage IVE; bulky tumor mass had 3 patients. All patients had Eastern Cooperative Oncology Group (ECOG performance status (PS 0 or 1. Five patients received monochemotherapy with chlorambucil and 3 were treated with CHOP regimen (cyclophosphamide, doxorubicin, vincristine and prednisone. A complete response (CR was achieved in 5 patients and a partial response (PR in 3 of them, treated with chlorambucil monotherapy and CHOP regimen. All patients were alive during a median follow-up period of 49 months (range 6- 110 months. Three patients relapsed after monochemotherapy into the other extranodal localization. They were treated with CHOP regimen and remained in stable PR. Conclusion. BALT lymphoma tends to be localised disease at the time of diagnosis, responds well

  10. Stratigraphical and sedimentary characters of Late Cretaceous formations outcropping in central and southern Tunisia, Tethyan southern margin (United States)

    Jaballah, J.; Negra, M. H.


    The main goals of our approach are to identify some local to global events in relation with tectonic instabilities and/or sea-level changes, occurring during the deposition of Cenomanian-Coniacian carbonate series in Tunisia. Several sections surveyed in Central-Southern Tunisia, along a North-South transect extending from Sidi Bouzid to Gafsa area, show that the Cenomanian-Coniacian series include rudist-rich facies associated to other shallow marine to deeper deposits. Detailed sedimentological studies supported by new biostratigraphical data (provided by H. Bismuth, oral comm.), have allowed to add more precisions on the lithostratigraphical stacking and thus on the Central Tunisia Stratigraphic Chart. Some carbonate members such as the Middle Turonian Bireno and the Late Turonian-Coniacian Douleb have been identified in certain localities for the first time. Indeed, these members were never described before at Jebel el Kébar and Jebel Meloussi. In the Sidi Bouzid area, especially at Jebel el Kébar, the Cenomanian-Coniacian carbonate members are characterized by frequent and rapid changes, related to the existence of highs (horsts, probably) and depressed depositional domains (grabens, probably), which formed during the deposition of the two lower Units of the Middle Turonian Bireno Member. Above, the Late Turonian to Coniacian deposits, have tended to seal the irregular paleotopography affected, at least locally, by Middle Turonian extensional tectonic movements. They could be related, in contrast, to a drowning linked to a sea level rise. Similar events were described abroad during Late Turonian times; a partial drowning of carbonate platforms was already identified in other localities of the African Tethyan margin. However, the global drowning corresponding to the C/T event was not identified in the present study, although previous works have described this event North of the studied sector. As demonstrated in other localities, a global eustatic event could

  11. Lower crustal intrusions beneath the southern Baikal Rift Zone

    DEFF Research Database (Denmark)

    Nielsen, Christoffer; Thybo, Hans


    The Cenozoic Baikal Rift Zone (BRZ) is situated in south-central Siberia in the suture between the Precambrian Siberian Platform and the Amurian plate. This more than 2000-km long rift zone is composed of several individual basement depressions and half-grabens with the deep Lake Baikal at its ce...

  12. The endocytic adaptor Eps15 controls marginal zone B cell numbers.

    Directory of Open Access Journals (Sweden)

    Benedetta Pozzi

    Full Text Available Eps15 is an endocytic adaptor protein involved in clathrin and non-clathrin mediated endocytosis. In Caenorhabditis elegans and Drosophila melanogaster lack of Eps15 leads to defects in synaptic vesicle recycling and synapse formation. We generated Eps15-KO mice to investigate its function in mammals. Eps15-KO mice are born at the expected Mendelian ratio and are fertile. Using a large-scale phenotype screen covering more than 300 parameters correlated to human disease, we found that Eps15-KO mice did not show any sign of disease or neural deficits. Instead, altered blood parameters pointed to an immunological defect. By competitive bone marrow transplantation we demonstrated that Eps15-KO hematopoietic precursor cells were more efficient than the WT counterparts in repopulating B220⁺ bone marrow cells, CD19⁻ thymocytes and splenic marginal zone (MZ B cells. Eps15-KO mice showed a 2-fold increase in MZ B cell numbers when compared with controls. Using reverse bone marrow transplantation, we found that Eps15 regulates MZ B cell numbers in a cell autonomous manner. FACS analysis showed that although MZ B cells were increased in Eps15-KO mice, transitional and pre-MZ B cell numbers were unaffected. The increase in MZ B cell numbers in Eps15 KO mice was not dependent on altered BCR signaling or Notch activity. In conclusion, in mammals, the endocytic adaptor protein Eps15 is a regulator of B-cell lymphopoiesis.

  13. Defective anti-polysaccharide response and splenic marginal zone disorganization in ALPS patients. (United States)

    Neven, Bénédicte; Bruneau, Julie; Stolzenberg, Marie-Claude; Meyts, Isabelle; Magerus-Chatinet, Aude; Moens, Leen; Lanzarotti, Nina; Weller, Sandra; Amiranoff, Denise; Florkin, Benoit; Bader-Meunier, Brigitte; Leverger, Guy; Ferster, Alice; Chantrain, Christophe; Blanche, Stéphane; Picard, Capucine; Molina, Thierry Jo; Brousse, Nicole; Durandy, Anne; Rizzi, Marta; Bossuyt, Xavier; Fischer, Alain; Rieux-Laucat, Frederic


    Autoimmune lymphoproliferative syndrome (ALPS) caused by impaired FAS-mediated apoptosis of lymphocytes is characterized by lymphoproliferation, autoimmunity, but also an increased risk of invasive bacterial infection, notably following splenectomy. We surveyed a cohort of 100 ALPS patients (including 33 splenectomized) and found that 12 (10 splenectomized) had experienced 23 invasive bacterial infections mainly caused by Streptococcus pneumoniae. This vulnerability was associated with evidence of defective B-cell function characterized by low serum immunoglobulin (Ig) M, low IgM antibody production in response to S pneumoniae following nonconjugated immunization, and low blood memory B-cells counts (including marginal zone [MZ] B-cell counts). This immunodeficiency strongly correlated with intensity of lymphoproliferation. Spleen sections from 9 ALPS patients revealed double-negative T-cell (DN-T) infiltration of the MZ, which was depleted of B cells. MZ in ALPS patients contained an abnormally thick layer of MAdCAM-1((+)) stromal cells and an excess of DN-Ts. DN-Ts were shown to express MAdCAM-1 ligand, the α4β7 integrin. These observations suggest that accumulating DN-Ts are trapped within stromal cell meshwork and interfere with correct localization of MZ B cells. Similar observations were made in spleens of fas-deficient mice. Our data revealed an unexpected mechanism by which ALPS results in anti-polysaccharide IgM antibody production-specific defect. Splenectomy should be avoided. © 2014 by The American Society of Hematology.

  14. Modelling wave-induced sea ice break-up in the marginal ice zone (United States)

    Montiel, F.; Squire, V. A.


    A model of ice floe break-up under ocean wave forcing in the marginal ice zone (MIZ) is proposed to investigate how floe size distribution (FSD) evolves under repeated wave break-up events. A three-dimensional linear model of ocean wave scattering by a finite array of compliant circular ice floes is coupled to a flexural failure model, which breaks a floe into two floes provided the two-dimensional stress field satisfies a break-up criterion. A closed-feedback loop algorithm is devised, which (i) solves the wave-scattering problem for a given FSD under time-harmonic plane wave forcing, (ii) computes the stress field in all the floes, (iii) fractures the floes satisfying the break-up criterion, and (iv) generates an updated FSD, initializing the geometry for the next iteration of the loop. The FSD after 50 break-up events is unimodal and near normal, or bimodal, suggesting waves alone do not govern the power law observed in some field studies. Multiple scattering is found to enhance break-up for long waves and thin ice, but to reduce break-up for short waves and thick ice. A break-up front marches forward in the latter regime, as wave-induced fracture weakens the ice cover, allowing waves to travel deeper into the MIZ.


    Directory of Open Access Journals (Sweden)

    Salvatore Perrone


    Full Text Available Marginal zone lymphomas have been associated with several infectious agents covering both viral and bacterial pathogens and in some cases a clear aetiological role has been established. Pathogenetic mechanisms are currently not completely understood, however the role of chronic stimulation of the host immune response with persistent lymphocyte activation represents the most convincing explanation for lymphoproliferation. Gastric MALT lymphoma is strictly associated with Helicobacter pylori infection and various eradicating protocols, developed due to increasing antibiotic resistance, represent the first line therapy. The response rate to eradication is good with 80% of response at 1 year; this finding is also noteworthy because recapitulates a cancer cured only by antibacterial approach and it satisfies the Koch postulates of causation, establishing a causative relationship between Hp and gastric MALT lymphoma. Patients with chronic HCV infection have 5 times higher risk to develop MZL, in particular an association with splenic and nodal MZL has been shown in several studies. Moreover, there is evidence of lymphoma regression after antiviral therapy with interferon+ribavirin, thus rising hope that new available drugs, extremely effective against HCV replication, could improve outcome also in HCV-driven lymphomas. The rare cases of MZL localized to orbital fat and eye conjunctivas have been associated with Chlamydia psittaci infection carried by birds. Efficacy of antibacterial therapy against C. psittaci are conflicting and generally poorer thain gastric MALT. Finally some case-reports will cover the relationship between primary cutaneous B-cell Lymphomas and Borrelia Burgdorferi.

  16. Employment of Oligodeoxynucleotide plus Interleukin-2 Improves Cytogenetic Analysis in Splenic Marginal Zone Lymphoma

    Directory of Open Access Journals (Sweden)

    Antonella Bardi


    Full Text Available To compare the efficiency of novel mitogenic agents and traditional mitosis inductors, 18 patients with splenic marginal zone lymphoma (SMZL were studied. Three cultures using oligodeoxynucleotide (ODN plus interleukin-2 (IL-2, or TPA, or LPS were setup in each patient. Seventeen/18 cases with ODN+IL2 had moderate/good proliferation (94,4% as compared with 10/18 cases with TPA and LPS (55% (P=.015; 14/18 (77,7% cases with ODN+IL2 had sufficient good quality of banding as compared with 8/18 cases (44,4% with TPA and LPS. The karyotype could be defined from ODN+IL2-stimulated cultures in all 18 patients, 14 of whom (77,7% had a cytogenetic aberration, whereas clonal aberrations could be documented in 9 and in 3 cases by stimulation with LPS and TPA, respectively. Recurrent chromosome aberrations in our series were represented by aberrations of chromosome 14q in 5 patients, by trisomy 12 and 7q deletion in 4 cases each, and by abnormalities involving 11q and 13q in two cases each. These findings show that stimulation with ODN+IL2 offers more mitotic figures of better quality and results in an increased rate of clonal aberrations in SMZL, making this method ideal for prospective studies aiming at the definition of the prognostic impact of cytogenetic aberrations in this disorder.

  17. Modelling wave-induced sea ice break-up in the marginal ice zone. (United States)

    Montiel, F; Squire, V A


    A model of ice floe break-up under ocean wave forcing in the marginal ice zone (MIZ) is proposed to investigate how floe size distribution (FSD) evolves under repeated wave break-up events. A three-dimensional linear model of ocean wave scattering by a finite array of compliant circular ice floes is coupled to a flexural failure model, which breaks a floe into two floes provided the two-dimensional stress field satisfies a break-up criterion. A closed-feedback loop algorithm is devised, which (i) solves the wave-scattering problem for a given FSD under time-harmonic plane wave forcing, (ii) computes the stress field in all the floes, (iii) fractures the floes satisfying the break-up criterion, and (iv) generates an updated FSD, initializing the geometry for the next iteration of the loop. The FSD after 50 break-up events is unimodal and near normal, or bimodal, suggesting waves alone do not govern the power law observed in some field studies. Multiple scattering is found to enhance break-up for long waves and thin ice, but to reduce break-up for short waves and thick ice. A break-up front marches forward in the latter regime, as wave-induced fracture weakens the ice cover, allowing waves to travel deeper into the MIZ.

  18. The ciliary margin zone of the mammalian retina generates retinal ganglion cells (United States)

    Marcucci, Florencia; Murcia-Belmonte, Veronica; Coca, Yaiza; Ferreiro-Galve, Susana; Wang, Qing; Kuwajima, Takaaki; Khalid, Sania; Ross, M. Elizabeth; Herrera, Eloisa; Mason, Carol


    Summary The retina of lower vertebrates grows continuously by integrating new neurons generated from progenitors in the ciliary margin zone (CMZ). Whether the mammalian CMZ provides the neural retina with retinal cells is controversial. Live-imaging of embryonic retina expressing eGFP in the CMZ shows that cells migrate laterally from the CMZ to the neural retina where differentiated retinal ganglion cells (RGCs) reside. As Cyclin D2, a cell-cycle regulator, is enriched in ventral CMZ, we analyzed Cyclin D2−/− mice to test whether the CMZ is a source of retinal cells. Neurogenesis is diminished in Cyclin D2 mutants, leading to a reduction of RGCs in the ventral retina. In line with these findings, in the albino retina, the decreased production of ipsilateral RGCs is correlated with fewer Cyclin D2+ cells. Together, these results implicate the mammalian CMZ as a neurogenic site that produces RGCs and whose proper generation depends on Cyclin D2 activity. PMID:28009286

  19. Cambrian-lower Middle Ordovician passive carbonate margin, southern Appalachians: Chapter 14 (United States)

    Read, J. Fred; Repetski, John E.


    The southern Appalachian part of the Cambrian–Ordovician passive margin succession of the great American carbonate bank extends from the Lower Cambrian to the lower Middle Ordovician, is as much as 3.5 km (2.2 mi) thick, and has long-term subsidence rates exceeding 5 cm (2 in.)/k.y. Subsiding depocenters separated by arches controlled sediment thickness. The succession consists of five supersequences, each of which contains several third-order sequences, and numerous meter-scale parasequences. Siliciclastic-prone supersequence 1 (Lower Cambrian Chilhowee Group fluvial rift clastics grading up into shelf siliciclastics) underlies the passive margin carbonates. Supersequence 2 consists of the Lower Cambrian Shady Dolomite–Rome-Waynesboro Formations. This is a shallowing-upward ramp succession of thinly bedded to nodular lime mudstones up into carbonate mud-mound facies, overlain by lowstand quartzose carbonates, and then a rimmed shelf succession capped by highly cyclic regressive carbonates and red beds (Rome-Waynesboro Formations). Foreslope facies include megabreccias, grainstone, and thin-bedded carbonate turbidites and deep-water rhythmites. Supersequence 3 rests on a major unconformity and consists of a Middle Cambrian differentiated rimmed shelf carbonate with highly cyclic facies (Elbrook Formation) extending in from the rim and passing via an oolitic ramp into a large structurally controlled intrashelf basin (Conasauga Shale). Filling of the intrashelf basin caused widespread deposition of thin quartz sandstones at the base of supersequence 4, overlain by widespread cyclic carbonates (Upper Cambrian lower Knox Group Copper Ridge Dolomite in the south; Conococheague Formation in the north). Supersequence 5 (Lower Ordovician upper Knox in the south; Lower to Middle Ordovician Beekmantown Group in the north) has a basal quartz sandstone-prone unit, overlain by cyclic ramp carbonates, that grade downdip into thrombolite grainstone and then storm

  20. Late Palaeozoic heavy mineral and clast modes from the Betic Cordillera (southern Spain): transition from a passive to an active continental margin (United States)

    Herbig, Hans-Georg; Stattegger, Karl


    Silurian to Late Carboniferous sediments constitute most of the uppermost nappe (Malaguides) in the internal zone of the Betic Cordillera. The sediments represent continuous deep-water environments dominated by flysch deposition. Repeated changes between acid plutonic/recycled cratonic and metamorphic sedimentary input are evidenced by heavy mineral spectra and psephitic clast modes of the Devonian-Carboniferous formations. Oscillations and amplitudes, especially of metamorphic detrital influx, become more frequent and larger, respectively, near the Variscan disconformity. Permo-Triassic redbeds are clearly post-orogenic sediments according to lithofacies and heavy mineral content. The joint development of lithofacies, clast modes and heavy mineral spectra demonstrates the transition from a passive to an active continental margin during the Palaeozoic: the Silurian-Devonian sediments of the Malaguide realm were deposited during a divergent cratonic stage north of the Betico-Rifean block, which is a detached sliver of the African plate. The Viséan-Upper Carboniferous formations record the collision orogenic stage between the Betico-Rifean block and the southern margin of the Southern Europe plate. The collision processes induced strong uplift and erosion of successively shallowing carbonate shelf realms and the connected crystalline, mostly metamorphic hinterland. The source area was the Betico-Rifean block south of the Malaguide basin. Palaeogeographic connections of the Malaguides, especially with Minorca (Baleares), are shortly discussed.

  1. SIGNR1-Negative Red Pulp Macrophages Protect against Acute Streptococcal Sepsis after Leishmania donovani-Induced Loss of Marginal Zone Macrophages

    NARCIS (Netherlands)

    Kirby, A.C.; Beattie, L.; Maroof, A.; Rooijen, van N.; Kaye, P.M.


    Marginal zone macrophages in the murine spleen play an important role in the capture of blood-borne pathogens and are viewed as an essential component of host defense against the development of pneumococcal sepsis. However, we and others have previously described the loss of marginal zone

  2. The Central Alborz Permian basaltic magmatism: an evidence of southern passive continental margin of Paleo- Tethys

    Directory of Open Access Journals (Sweden)

    Morteza Delavari


    Full Text Available The study area is located in the Central Alborz (northeast of Baladeh. The Permianmagmatism in this area occurs as a basaltic unit between Ruteh-Nessen Formation.Petrographically, the rocks are plagioclase phyric and geochemically, display alkalinesodic nature. Chondrite- normalized rare earth element (REE patterns are extremely LREE- enriched similar to those of oceanic island basalts (OIB with (La/SmN,(Sm/YbN and (La/YbN in the ranges of 1.95- 4.62, 4.23- 5.45 and 8.30- 20.52,respectively. Furthermore, primitive mantle normalized multi element diagramsrepresent OIB characteristics. Modeling based on trace element values and the contentof some major elements reveal low degree partial melting (< 10% of a deep (~110 kmgarnet-bearing mantle source. In addition, variation of some trace element ratios such asNb/Rb, K/La, La/Nb, Ba/Nb, Th/Nb and K/Nb suggests a HIMU mantle origin. As thesamples geochemically show intra-plate tectonomagmatic setting without subductionzone signatures. Thus, during the Permian (and earlier times, Alborz has been as apassive continental margin in the southern border of Paleo-Tethys and its magmatism was more probably affected by extensional tectonism or mantle plume activity related toearlier stages of Neo-Tethys ocean development.

  3. Morphosedimentary expression of the Giant Pock Mark structure known as the "Gran Burato" (Transitional Zone, Galicia continental margin) (United States)

    Lopez, Angel Enrique; Rubio, Belén; Rey, Daniel; Mohamed, Kais; Alvarez, Paula; Plaza-Morlote, Maider; Bernabeu, Ana; Druet, Maria; Martins, Virginia


    This paper presents the characterization of the sedimentary environment and other sedimentological features of the Transitional Zone of the Galicia continental margin, in the vicinity of the giant pock -mark structure known as the Gran Burato. The area is characterized by marginal platforms and a horst-graben system controlled by NW-SE oriented normal faults. In this zone, three giant pockmark structures, one of them known as the Gran Burato, were reported as associated to large-scale fluid escapes. The study area is located on the Transitional Zone (TZ) of the Galicia passive continental margin, which extends from Cape Finisterre (43o N) in the North to around 40oN in the South. This margin shows a complex structural configuration, which is reflected in the seabed, owing to tectonic movements from Mesozoic rifting phases and Eocene compression (Pyrennean Orogeny). Sedimentological, geochemical and physical properties analysis and 14C AMS-dating of a 4 m piston core extracted in the vicinity of the Gran Burato complemented by multibeam and TOPAS surveys allowed characterizing of the sedimentary environment in the study area. The interpretation of these data showed that the sedimentary and tectonic evolution of the area controlled by the activity of fluid dynamics.

  4. MIZMAS: Modeling the Evolution of Ice Thickness and Floe Size Distributions in the Marginal Ice Zone of the Chukchi and Beaufort Seas (United States)


    Size Distributions in the Marginal Ice Zone of the Chukchi and Beaufort Seas Jinlun Zhang Applied Physics Laboratory, University of Washington...high-resolution coupled sea ice–ocean modeling and assimilation system that is capable of accurately predicting sea ice conditions in the marginal ice...the scientific objectives, we plan to develop, implement, and validate a new coupled ice– ocean Marginal Ice Zone Modeling and Assimilation System

  5. Fault Zone Architecture and Mineralogy: Implications in Fluid Flow and Permeability in Crustal Scale Fault Zones in the Southern Andes. (United States)

    Roquer, T.; Terrón, E.; Perez-Flores, P.; Arancibia, G.; Cembrano, J. M.


    Fluid flow in the upper crust is controlled by the permeability and interconnection of fractures in the fault zones. The permeability within the fault zone is determined by its activity, architecture and, in particular, by the mineralogy of the core and the damage zone. Whereas the permeability structure of a fault zone can be defined by the volume proportion of the core with respect to the damage zone, the relationship between the mineralogy and permeability along fault zones still remains obscure. This work examines structural and mineralogical data to show the relationship between the mineral composition of the fault zone with its permeability in the Liquiñe-Ofqui Fault System (LOFS) and the Arc-oblique Long-lived Fault Systems (ALFS), Southern Chile. The LOFS is an active ca. 1200 km long strike-slip Cenozoic intra-arc structure that strikes NNE in its master traces and NE in its subsidiary traces, with dextral and dextral-normal movement mostly developed in the last 6 My. Although the LOFS and the ALFS cross-cut each other, the ALFS is an apparently older basement fault system where seismic and field evidences record sinistral, sinistral-normal and sinistral-reverse movements. One 22-m-long NE transect was mapped orthogonal to a segment of the ALFS, where host rocks are Miocene andesitic rocks. Structural and XRD sampling were conducted in the core and damage zone. Structural mapping shows a multiple core, NW-striking fault zone with foliated gouge and an asymmetric damage zone, where the hanging wall has significantly higher mesoscopic fracture density than the footwall. The hanging wall is characterized by NW-striking, steeply dipping veins. Preliminary XRD results indicate the presence of homogenously distributed Ca-rich zeolite (mainly laumontite) in the core and the veins of the damage zone, which could indicate that the core acted as a conduit for low-temperature (ca. 220°C) fluids.

  6. Sediment accumulation on the Southern California Bight continental margin during the twentieth century (United States)

    Alexander, C.R.; Lee, H.J.


    Sediment discharged into the portion of the Southern California Bight extending from Santa Barbara to Dana Point enters a complex system of semi-isolated coastal cells, narrow continental shelves, submarine canyons, and offshore basins. On both the Santa Monica and San Pedro margins, 210Pb accumulation rates decrease in an offshore direction (from ??0.5 g cm-2yr-1 to 0.02 g cm-2yr -1), in concert with a fining in sediment grain size (from 4.5?? to 8.5??), suggesting that offshore transport of wave-resuspended material occurs as relatively dilute nepheloid layers and that hemiplegic sedimentation dominates the supply of sediment to the outer shelf, slope, and basins. Together, these areas are effectively sequestering up to 100% of the annual fluvial input. In contrast to the Santa Monica margin, which does not display evidence of mass wasting as an important process of sediment delivery and redistribution, the San Pedro margin does provide numerous examples of failures and mass wasting, suggesting that intraslope sediment redistribution may play a more important role there. Basin deposits in both areas exhibit evidence of turbidites tentatively associated with both major floods and earthquakes, sourced from either the Redondo Canyon (San Pedro Basin) or Dume Canyon (Santa Monica Basin). On the Palos Verdes shelf, sediment-accumulation rates decrease along and across the shelf away from the White's Point outfall, which has been a major source of contaminants to the shelf deposits. Accumulation rates prior to the construction of the outfall were ??0.2 g cm-2yr-1 and increased 1.5-3.7 times during peak discharges from the outfall in 1971. The distal rate of accumulation has decreased by ??50%, from 0.63 g cm -2yr-1 during the period 1971-1992 to 0.29 g cm -2yr-1 during the period 1992-2003. The proximal rate of accumulation, however, has only decreased ??10%, from 0.83 g cm -2yr-1 during the period 1971-1992 to 0.73 g cm -2yr-1 during the period 1992-2003. Effluent

  7. Ecological zones in the Southern Appalachians: first approximation (United States)

    Steven A. Simon; Thomas K. Collins; Gary L. Kauffman; W. Henry McNab; Christopher J. Ulrey


    Forest environments of the Southern Appalachian Mountains and their characteristic plant communities are among the most varied in the Eastern United States. Considerable data are available on the distribution of plant communities relative to temperature and moisture regimes, but not much information on fertility as an environmental influence has been published; nor has...

  8. CR2+ marginal zone B cell production of pathogenic natural antibodies is C3 independent. (United States)

    Woods, Keith M; Pope, Michael R; Hoffman, Sara M; Fleming, Sherry D


    Intestinal ischemia-reperfusion (IR)-induced damage requires complement receptor 2 (CR2) for generation of the appropriate natural Ab repertoire. Pathogenic Abs recognize neoantigens on the ischemic tissue, activate complement, and induce intestinal damage. Because C3 cleavage products act as ligands for CR2, we hypothesized that CR2(hi) marginal zone B cells (MZBs) require C3 for generation of the pathogenic Abs. To explore the ability of splenic CR2(+) B cells to generate the damaging Ab repertoire, we adoptively transferred either MZBs or follicular B cells (FOBs) from C57BL/6 or Cr2(-/-) mice into Rag-1(-/-) mice. Adoptive transfer of wild type CR2(hi) MZBs but not CR2(lo) FOBs induced significant damage, C3 deposition, and inflammation in response to IR. In contrast, similarly treated Rag-1(-/-) mice reconstituted with either Cr2(-/-) MZB/B1 B cells (B1Bs) or FOBs lacked significant intestinal damage and displayed limited complement activation. To determine whether C3 cleavage products are critical in CR2-dependent Ab production, we evaluated the ability of the natural Ab repertoire of C3(-/-) mice to induce damage in response to IR. Infusion of C3(-/-) serum into Cr2(-/-) mice restored IR-induced tissue damage. Furthermore, Rag-1(-/-) mice sustained significant damage after infusion of Abs from C3(-/-) but not Cr2(-/-) mice. Finally, adoptive transfer of MZBs from C3(-/-) mice into Rag-1(-/-) mice resulted in significant tissue damage and inflammation. These data indicate that CR2 expression on MZBs is sufficient to induce the appropriate Abs required for IR-induced tissue damage and that C3 is not critical for generation of the pathogenic Abs.

  9. Small-Scale Modeling of Waves and Floes in the Marginal Ice Zone (United States)

    Orzech, M.; Shi, F.; Calantoni, J.; Bateman, S. P.; Veeramony, J.


    We are conducting a model-based investigation into the small-scale (O(m)) physics of wave-ice floe interaction in the marginal ice zone (MIZ), in order to test and improve parameterizations utilized by large-scale climate models. The presentation will describe the development and validation of a coupled system to track the wave-forced motion of floating objects (collections of bonded particles) and the concurrent effects of the moving objects on the surrounding fluid. NHWAVE, a fully dispersive wave model with a vertical sigma-coordinate, is extended to model moving objects by including vertical boundary fitted meshing and horizontal immersed boundary method. LIGGGHTS, a discrete element granular particle-tracking simulator, is configured to include realistic bonding forces between elements and incorporate velocity and pressure gradient effects from the fluid model. Following an overview of the coupled system, validation results will be presented for the standalone wave and ice models. For NHWAVE, model estimates of surface wave patterns generated by oscillating surface objects are compared to LIDAR measurements from corresponding laboratory experiments. For LIGGGHTS, the stress-strain response is measured for collections of bonded particles under tension and/or compression, then compared to available lab and field data. Results will also be presented from simplified MIZ simulations with the coupled system, in which waves pass through groups of rigid ice blocks and their refraction, diffraction, and reflection are measured. Finally, we will provide a preview of an upcoming series of targeted virtual experiments in which momentum/energy exchange between waves and ice floes is measured under varied conditions.

  10. Microbial methanogenesis in the sulfate-reducing zone of surface sediments traversing the Peruvian margin (United States)

    Maltby, J.; Sommer, S.; Dale, A. W.; Treude, T.


    We studied the concurrence of methanogenesis and sulfate reduction in surface sediments (0-25 cm below sea floor) at six stations (70, 145, 253, 407, 990 and 1024 m) along the Peruvian margin (12° S). This oceanographic region is characterized by high carbon export to the seafloor creating an extensive oxygen minimum zone (OMZ) on the shelf, both factors that could favor surface methanogenesis. Sediments sampled along the depth transect traversed areas of anoxic and oxic conditions in the bottom-near water. Net methane production (batch incubations) and sulfate reduction (35S-sulfate radiotracer incubation) were determined in the upper 0-25 cm b.s.f. of multiple cores from all stations, while deep hydrogenotrophic methanogenesis (> 30 cm b.s.f., 14C-bicarbonate radiotracer incubation) was determined in two gravity cores at selected sites (78 and 407 m). Furthermore, stimulation (methanol addition) and inhibition (molybdate addition) experiments were carried out to investigate the relationship between sulfate reduction and methanogenesis.Highest rates of methanogenesis and sulfate reduction in the surface sediments, integrated over 0-25 cm b.s.f., were observed on the shelf (70-253 m, 0.06-0.1 and 0.5-4.7 mmol m-2 d-1, respectively), while lowest rates were discovered at the deepest site (1024 m, 0.03 and 0.2 mmol m-2 d-1, respectively). The addition of methanol resulted in significantly higher surface methanogenesis activity, suggesting that the process was mostly based on non-competitive substrates - i.e., substrates not used by sulfate reducers. In the deeper sediment horizons, where competition was probably relieved due to the decrease of sulfate, the usage of competitive substrates was confirmed by the detection of hydrogenotrophic activity in the sulfate-depleted zone at the shallow shelf station (70 m).Surface methanogenesis appeared to be correlated to the availability of labile organic matter (C / N ratio) and organic carbon degradation (DIC production

  11. Chemostratigraphic Constraints on Late Jurassic Paleoceanography of the East Texas Basin, Southern Margin of North America (United States)

    Mainali, P.; Rowe, H. D.


    Late Jurassic deposition of organic-rich muds occurred in the East Texas Basin of modern-day Texas and Louisiana in a ramp-style marine setting during the early formation of the Gulf of Mexico. These mudrocks are regional known as the Haynesville and Bossier Formations. The goals of the current project are to 1) develop a better understanding of the paleoceanographic conditions and the depositional environment, and 2) develop linkages between the record from the southern margin of North America and other well-documented paleoceanographic records of Kimmeridgian age. Ten drill cores from the study area have been studied for their geochemistry. Each core was scanned at a 1-foot interval using a handheld x-ray fluorescence instrument, providing rapid, quantitative analysis of the following elemental concentrations: Mg, Al, S, Si, P, K, Ti, Ca, Mn, Fe, Mo, Cr, Ni, Cu, Zn, Th, Rb, U, Sr, Zr, and V. In addition, preliminary interpretations for total inorganic carbon (TIC), total organic carbon (TOC), total nitrogen (%N), and bulk rock TOC and N isotopic composition of core samples reveal distinct differences between the Bossier and Haynesville formations. Results from previous geochemical studies suggest that the siliciclastic-dominated Bossier formation has less TOC than the underlying Haynesville formation. Furthermore, the Haynesville is much more carbonate-rich (calcite) than the overlying Bossier. An upwardly increasing trend in Si/Al in some cores suggests increasing detrital quartz influx. A linear relationship between Fe and Al suggest that iron is primarily in clay mineral phases in the Haynesville. Enrichments in Mo concentrations and Cr/V ratios reveal periods of anoxic conditions.

  12. Pre-collisional accretionary growth of the southern Laurasian active margin, Central Pontides, Turkey (United States)

    Aygül, Mesut; Okay, Aral I.; Oberhänsli, Roland; Sudo, Masafumi


    Cretaceous subduction-accretionary complexes crop out over wide areas in the central part of the Pontides, northern Turkey. To the north, the wedge consists of a low-grade metaflysch sequence with blocks of marble, Na-amphibole-bearing metabasite (PT = 7-12 kbar; 400 ± 70 °C) and serpentinite. 40Ar/39Ar phengite ages from the phyllites of the metaflysch are ca. 100 Ma. The metaflysch sequence is underlain by oceanic crust-derived HP/LT metabasites and micaschists along a major detachment fault. The metabasites are epidote-blueschists consisting of glaucophane, epidote, titanite, and phengite locally with garnet. Fresh lawsonite-blueschists are exposed as blocks along the detachment fault. Peak metamorphic conditions of a garnet-blueschist are constrained to 17 ± 1 kbar and 500 ± 40 °C and of a lawsonite-blueschist to 14 ± 2 kbar and 370-440 °C. 40Ar/39Ar phengite dating on the micaschists constrains the HP/LT metamorphism as 101-92 Ma, younging southward. Middle Jurassic (ca. 160 Ma) accretionary complexes consisting of blueschist to lower greenschist facies metabasites, marble and volcanogenic metasediment intercalations are exposed at the southern part of the Cretaceous wedge. In the studied area, the North Anatolian Fault forms the contact between Cretaceous and Middle Jurassic HP/LT metamorphic rocks. Wide distribution of Cretaceous subduction-accretionary complexes implies accretionary tectonic continental growth along the Laurasian active margin. High amount of clastic sediment flux into the trench has a major effect on enlarging the wedge during the Albian. Tectonic thickening of the oceanic HP/LT metamorphic sequence, however, was possibly achieved by propagation of the décollement along the retreating slab which can create the space necessary for progressive deep level basal underplating and extension of the wedge for subsequent syn-subduction exhumation.

  13. Bovine Mastitis in Selected Districts of Borena Zone, Southern Ethiopia

    African Journals Online (AJOL)

    A cross-sectional study was conducted on 397 lactating Boran cows in pastoral areas of Borana Zone, Ethiopia to determine the prevalence of mastitis, major causes and ... The prevalence of mastitis was significantly higher (p=0.00) among animals with tick infestation and those with history of previous exposure to mastitis ...

  14. Bovine Mastitis in Selected Districts of Borena Zone, Southern Ethiopia

    African Journals Online (AJOL)

    A cross-sectional study was conducted on 397 lactating Boran cows in pastoral areas of Borana Zone, Ethiopia to determine the prevalence of mastitis, major causes and associated risk factors of mastitis using California mastitis test and bacteriology. The study showed an overall prevalence of 70.8%; out of which 12.4% ...

  15. Geology of the continental margin beneath Santa Monica Bay, Southern California, from seismic-reflection data (United States)

    Fisher, M.A.; Normark, W.R.; Bohannon, R.G.; Sliter, R.W.; Calvert, A.J.


    We interpret seismic-reflection data, which were collected in Santa Monica Bay using a 70-in3 generator-injector air gun, to show the geologic structure of the continental shelf and slope and of the deep-water, Santa Monica and San Pedro Basins. The goal of this research is to investigate the earthquake hazard posed to urban areas by offshore faults. These data reveal that northwest of the Palos Verdes Peninsula, the Palos Verdes Fault neither offsets the seafloor nor cuts through an undeformed sediment apron that postdates the last sea level rise. Other evidence indicates that this fault extends northwest beneath the shelf in the deep subsurface. However, other major faults in the study area, such as the Dume and San Pedro Basin Faults, were active recently, as indicated by an arched seafloor and offset shallow sediment. Rocks under the lower continental slope are deformed to differing degrees on opposite sides of Santa Monica Canyon. Northwest of this canyon, the continental slope is underlain by a little-deformed sediment apron; the main structures that deform this apron are two lower-slope anticlines that extend toward Point Dume and are cored by faults showing reverse or thrust separation. Southeast of Santa Monica Canyon, lower-slope rocks are deformed by a complex arrangement of strike-slip, normal, and reverse faults. The San Pedro Escarpment rises abruptly along the southeast side of Santa Monica Canyon. Reverse faults and folds underpinning this escarpment steepen progressively southeastward. Locally they form flower structures and cut downward into basement rocks. These faults merge downward with the San Pedro Basin fault zone, which is nearly vertical and strike slip. The escarpment and its attendant structures diverge from this strike-slip fault zone and extend for 60 km along the margin, separating the continental shelf from the deep-water basins. The deep-water Santa Monica Basin has large extent but is filled with only a thin (less than 1.5-km

  16. Paleoseismology of the Southern Section of the Black Mountains and Southern Death Valley Fault Zones, Death Valley, United States (United States)

    Sohn, Marsha S.; Knott, Jeffrey R.; Mahan, Shannon


    The Death Valley Fault System (DVFS) is part of the southern Walker Lane–eastern California shear zone. The normal Black Mountains Fault Zone (BMFZ) and the right-lateral Southern Death Valley Fault Zone (SDVFZ) are two components of the DVFS. Estimates of late Pleistocene-Holocene slip rates and recurrence intervals for these two fault zones are uncertain owing to poor relative age control. The BMFZ southernmost section (Section 1W) steps basinward and preserves multiple scarps in the Quaternary alluvial fans. We present optically stimulated luminescence (OSL) dates ranging from 27 to 4 ka of fluvial and eolian sand lenses interbedded with alluvial-fan deposits offset by the BMFZ. By cross-cutting relations, we infer that there were three separate ground-rupturing earthquakes on BMFZ Section 1W with vertical displacement between 5.5 m and 2.75 m. The slip-rate estimate is ∼0.2 to 1.8 mm/yr, with an earthquake recurrence interval of 4,500 to 2,000 years. Slip-per-event measurements indicate Mw 7.0 to 7.2 earthquakes. The 27–4-ka OSL-dated alluvial fans also overlie the putative Cinder Hill tephra layer. Cinder Hill is offset ∼213 m by SDVFZ, which yields a tentative slip rate of 1 to 8 mm/yr for the SDVFZ.

  17. Observations of surface momentum exchange over the marginal ice zone and recommendations for its parametrisation

    Directory of Open Access Journals (Sweden)

    A. D. Elvidge


    Full Text Available Comprehensive aircraft observations are used to characterise surface roughness over the Arctic marginal ice zone (MIZ and consequently make recommendations for the parametrisation of surface momentum exchange in the MIZ. These observations were gathered in the Barents Sea and Fram Strait from two aircraft as part of the Aerosol–Cloud Coupling And Climate Interactions in the Arctic (ACCACIA project. They represent a doubling of the total number of such aircraft observations currently available over the Arctic MIZ. The eddy covariance method is used to derive estimates of the 10 m neutral drag coefficient (CDN10 from turbulent wind velocity measurements, and a novel method using albedo and surface temperature is employed to derive ice fraction. Peak surface roughness is found at ice fractions in the range 0.6 to 0.8 (with a mean interquartile range in CDN10 of 1.25 to 2.85  ×  10−3. CDN10 as a function of ice fraction is found to be well approximated by the negatively skewed distribution provided by a leading parametrisation scheme (Lüpkes et al., 2012 tailored for sea-ice drag over the MIZ in which the two constituent components of drag – skin and form drag – are separately quantified. Current parametrisation schemes used in the weather and climate models are compared with our results and the majority are found to be physically unjustified and unrepresentative. The Lüpkes et al. (2012 scheme is recommended in a computationally simple form, with adjusted parameter settings. A good agreement holds for subsets of the data from different locations, despite differences in sea-ice conditions. Ice conditions in the Barents Sea, characterised by small, unconsolidated ice floes, are found to be associated with higher CDN10 values – especially at the higher ice fractions – than those of Fram Strait, where typically larger, smoother floes are observed. Consequently, the important influence of sea-ice morphology and floe size on

  18. Geology of the Elephanta Island fault zone, western Indian rifted margin, and its significance for understanding the Panvel flexure (United States)

    Samant, Hrishikesh; Pundalik, Ashwin; D'souza, Joseph; Sheth, Hetu; Lobo, Keegan Carmo; D'souza, Kyle; Patel, Vanit


    The Panvel flexure is a 150-km long tectonic structure, comprising prominently seaward-dipping Deccan flood basalts, on the western Indian rifted margin. Given the active tectonic faulting beneath the Panvel flexure zone inferred from microseismicity, better structural understanding of the region is needed. The geology of Elephanta Island in the Mumbai harbour, famous for the ca. mid-6th century A.D. Hindu rock-cut caves in Deccan basalt (a UNESCO World Heritage site) is poorly known. We describe a previously unreported but well-exposed fault zone on Elephanta Island, consisting of two large faults dipping steeply east-southeast and producing easterly downthrows. Well-developed slickensides and structural measurements indicate oblique slip on both faults. The Elephanta Island fault zone may be the northern extension of the Alibag-Uran fault zone previously described. This and two other known regional faults (Nhava-Sheva and Belpada faults) indicate a progressively eastward step-faulted structure of the Panvel flexure, with the important result that the individual movements were not simply downdip but also oblique-slip and locally even rotational (as at Uran). An interesting problem is the normal faulting, block tectonics and rifting of this region of the crust for which seismological data indicate a normal thickness (up to 41.3 km). A model of asymmetric rifting by simple shear may explain this observation and the consistently landward dips of the rifted margin faults.

  19. Late Permian topography at the southern margin of the Northern Permian Basin: Paleogeography inferred from 3D seismic analysis (United States)

    Clausen, Ole R.; Andresen, Katrine J.; Rasmussen, Jens A.


    The Top Pre Zechstein (TPZ) surface in the North Sea Basin is often mapped because it reveals the total basement tectonics in the area. In areas where Zechstein salt is present halokinetic processes, differential subsidence, and Mesozoic faulting however significantly alter the TPZ surface. The study area is located at the southern margin of the Northern Permian Basin in the eastern North Sea at the northern flank of the Ringkøbing-Fyn High. This area occurs approximately at the pinch-out line of the late Permian Zechstein salt and constitutes an excellent theater illustrating a range of salt-related problems. The TPZ surface is characterized by an overall NNW-ward dip defining the northern flank of the RFH and is transected by a set of NNW-SSE striking faults, and a E-W striking set of minor faults. Salt structures in the northern part of the study area introduce velocity pull-up (artefacts) at the TPZ surface and furthermore cause intense faulting of the Mesozoic and Cenozoic cover sediments. Pronounced isolated topographic highs similar to hills can be observed in the southern part of the study area where no to very little Zechstein evaporites are present. In the central part where Zechstein evaporites are present, small topographic highs similar to ridges can be observed at the footwall crest of minor faults. The Zechstein evaporites generally onlap towards the south in the study area but in the transitional zone around the hills, onlap from all directions onto the hills is observed. This suggests that the hills reflect paleo-topography developed during sub-aerial exposure before and perhaps during the deposition of the Zechstein sediments. The internal reflections within the hills show that they are composed of southward dipping sediments and very evident erosional truncations can be observed. The hills are aligned parallel to the major E-W striking basement fault, but are not directly associated to faults offsetting the TPZ surface. However, the alignment

  20. Phytoplankton and pigment patterns across frontal zones in the Atlantic sector of the Southern Ocean

    NARCIS (Netherlands)

    Van Leeuwe, M.A.; Kattner, G.; van Oijen, T.; de Jong, J.T.M.; de Baar, H.J.W.


    Phytoplankton distribution and concentrations of macronutrients and iron were studied in the Polar Frontal Zone (PFZ) and the eastern Weddell Gyre of the Southern Ocean, during austral autumn. HPLC analysis of algal pigments was combined with microscopy observations to assess algal distribution.

  1. Effects of riparian zone buffer widths on vegetation diversity in southern Appalachian headwater catchments (United States)

    Katherine J. Elliott; James M. Vose


    In mountainous areas such as the southern Appalachians USA, riparian zones are difficult to define. Vegetation is a commonly used riparian indicator and plays a key role in protecting water resources, but adequate knowledge of floristic responses to riparian disturbances is lacking. Our objective was to quantify changes in stand-level floristic diversity of...

  2. Evidence for Recent Extension and Volcanism inside the Southern Margin of Mare Frigoris (United States)

    Albin, Edward F.; Harris, R. Scott


    We report the identification of possible recent volcanic activity inside the southern margin of Mare Frigoris. Evidence includes two elliptical constructs with associated dark flows found at 56.6° N, - 19.7° W, north of the La Condamine J impact crater. They were discovered on high resolution (0.5 m/pixel) LROC WAC and NAC imagery (e.g., M188379739R and M142393589L) by the first author while performing a systematic geologic overview of the area.The constructs occur along a 3.2 km lineament trending southwest to northwest. The southwestern construct is the largest, measuring approximately 1.4 km in diameter by 65 m in height while the northeastern structure measures 1.2 km wide by 40 m high. The summits appear to be concave and contain well-defined pits 190 m and 120 m in diameter, respectively, each encircled by a deposit of raised material. Distinct dark deposits, exhibiting flow lobes, emanate from the pits. In addition, rubbly, flow-like dark deposits are found sporadically along the flanks of each feature.We interpret these structures as low profile steep-sided volcanic domes. Hawke et al. (2014) discussed volcanic constructs in the eastern part of Mare Frigoris; however, the features described in this study appear to be significantly younger. The domes may represent upwelling along a localized rift. Continued extension on the flanks appears to have released discrete dark flows. Well-defined flows crossing the floors of summit pits appear to have flowed uphill. We suggest that the evacuation of the magma chambers beneath these flows caused subsidence, forming the pits and giving the illusion that the lava flowed up and over the rims. Although the age of these constructs and flows is unknown, the paucity of impact craters suggests that they are relatively young. These could represent very recent eruptions of evolved magma on the Moon, similar to those reported by Jolliff et al. (2011). References: B. R. Hawke et al., 2014, LPSC, 45, 1318. Jolliff et al., 2012

  3. Early and abrupt retreat of the Laurentide Ice Sheet margin from the Mackenzie River valley, southern Northwest Territories (United States)

    Margold, Martin; Froese, Duane G.; Gosse, John C.; Yang, Guang; McKenna, Jillian; Hidy, Alan J.


    The detachment of the Laurentide Ice Sheet margin from the Canadian Cordillera opened the present-day drainage route of the Mackenzie River to the Arctic Ocean and an ice-free corridor that allowed for migration of species between Beringia and the mid-latitudes of North America. The existing ice-margin chronology depicts the southern reach of the Mackenzie River between 61 and 63° N as glaciated until about 13 ka, representing the last portion of the Laurentide Ice Sheet margin abutting the eastern foot of the Cordillera. A substantial retreat of the ice sheet margin in this region has been suggested to have occurred during the subsequent Younger Dryas cold period, despite the fact that in many other regions ice masses stabilised or even re-grew at this time. However, until now, deglacial chronometry for this region and the western LIS margin is sparse and consists mostly of minimum-limiting macrofossil and bulk C-14 ages from organics materials overlying glacial sediment. With the aim to bring new data on the deglaciation history of the Mackenzie River valley, we collected samples for Be-10 exposure dating from glacial erratic boulders in the southern Franklin Mountains that bound the Mackenzie River valley from the east. The sampling elevations ranged between 1480 and 800 m a.s.l., however, the measured ages show only a weak correlation with elevation. Instead, 10 out of 12 measured samples cluster tightly around 15 ka, with the remaining two samples likely containing Be-10 inherited from previous periods of exposure. Our results thus indicate a pre-Younger Dryas rapid down-wasting of the ice sheet surface, which we infer was accompanied by an ice margin retreat to the southeast. The southern reach of the Mackenzie River valley at the eastern foot of the Cordillera was, according to our results, ice free shortly after 15 ka, with the prospect that the ice-free corridor might have opened significantly earlier than hitherto anticipated. Further research is

  4. Investigations of Spatial and Temporal Variability of Ocean and Ice Conditions in and Near the Marginal Ice Zone. The “Marginal Ice Zone Observations and Processes Experiment” (MIZOPEX) Final Campaign Summary

    Energy Technology Data Exchange (ETDEWEB)

    DeMott, P. J. [Colorado State Univ., Fort Collins, CO (United States); Hill, T. C.J. [Colorado State Univ., Fort Collins, CO (United States)


    Despite the significance of the marginal ice zones of the Arctic Ocean, basic parameters such as sea surface temperature (SST) and a range of sea-ice characteristics are still insufficiently understood in these areas, and especially so during the summer melt period. The field campaigns summarized here, identified collectively as the “Marginal Ice Zone Ocean and Ice Observations and Processes Experiment” (MIZOPEX), were funded by U.S. National Aeronautic and Space Administration (NASA) with the intent of helping to address these information gaps through a targeted, intensive observation field campaign that tested and exploited unique capabilities of multiple classes of unmanned aerial systems (UASs). MIZOPEX was conceived and carried out in response to NASA’s request for research efforts that would address a key area of science while also helping to advance the application of UASs in a manner useful to NASA for assessing the relative merits of different UASs. To further exercise the potential of unmanned systems and to expand the science value of the effort, the field campaign added further challenges such as air deployment of miniaturized buoys and coordinating missions involving multiple aircraft. Specific research areas that MIZOPEX data were designed to address include relationships between ocean skin temperatures and subsurface temperatures and how these evolve over time in an Arctic environment during summer; variability in sea-ice conditions such as thickness, age, and albedo within the marginal ice zone (MIZ); interactions of SST, salinity, and ice conditions during the melt cycle; and validation of satellite-derived SST and ice concentration fields provided by satellite imagery and models.

  5. Receptor Activator of NF-κB Orchestrates Activation of Antiviral Memory CD8 T Cells in the Spleen Marginal Zone

    Directory of Open Access Journals (Sweden)

    Mohamed Habbeddine


    Full Text Available The spleen plays an important role in protective immunity to bloodborne pathogens. Macrophages and dendritic cells (DCs in the spleen marginal zone capture microbial antigens to trigger adaptive immune responses. Marginal zone macrophages (MZMs can also act as a replicative niche for intracellular pathogens, providing a platform for mounting the immune response. Here, we describe a role for RANK in the coordinated function of antigen-presenting cells in the spleen marginal zone and triggering anti-viral immunity. Targeted deletion of RANK results in the selective loss of CD169+ MZMs, which provide a niche for viral replication, while RANK signaling in DCs promotes the recruitment and activation of anti-viral memory CD8 T cells. These studies reveal a role for the RANKL/RANK signaling axis in the orchestration of protective immune responses in the spleen marginal zone that has important implications for the host response to viral infection and induction of acquired immunity.

  6. Three-Dimensional Thermal Structure of the Middle-America Subduction Zone: Along-margin mantle flow and slab metamorphism (United States)

    Rosas, J. C.; Currie, C. A.; He, J.


    Temperature is the primary control parameter of several processes occurring at subduction zones, such as slab metamorphism and dehydration, arc volcanism and the rupture width of megathrust earthquakes. The thermal state depends on the temperature of the oceanic slab and the flow pattern of the overlying mantle wedge. In most previous studies, mantle flow was modeled as two-dimensional (2D) corner flow, driven by the subducting plate. However, recent studies have shown the limitations of the 2D corner flow scheme, as a three-dimensional (3D) oceanic plate structure can generate along-strike pressure gradients, producing a trench-parallel flow component. One region where 3D effects may be important is the Middle America Subduction Zone (MASZ). Here, the dip of the oceanic plate varies from 0 to 70 degrees along the margin, with abrupt changes in slab dip in Central Mexico and Costa Rica-Nicaragua. Seismic anisotropy and arc magma geochemistry variations suggest a significant along-margin component of flow in these areas. Further, offshore surface heat flow measurements show that there may be along-margin variations in the temperature of the subducting oceanic plate, due to variations in plate age and hydrothermal circulation. In this study, we quantify the changes in the thermal structure of a subduction zone that result from along-margin variations in oceanic plate structure. We use 3D numerical models that consist of kinematically-defined subducting and overriding plates, and a flowing mantle wedge driven by drag exerted by the subducting plate. The finite-element code PGCtherm-3D is used to solve the steady-state governing equations for mantle wedge flow and the 3D thermal structure of the subduction zone. The models employ an oceanic plate that smoothly dips into the mantle and has along-margin variations in the deep dip of 40 and 70 degrees over a distance of 50km to 300km, as observed in some regions of the MASZ. Using an isoviscous mantle wedge, our

  7. Combination of hand-held probe and microscopy for fluorescence guided surgery in the brain tumor marginal zone. (United States)

    Richter, Johan C O; Haj-Hosseini, Neda; Hallbeck, Martin; Wårdell, Karin


    Visualization of the tumor is crucial for differentiating malignant tissue from healthy brain during surgery, especially in the tumor marginal zone. The aim of the study was to introduce a fluorescence spectroscopy-based hand-held probe (HHF-probe) for tumor identification in combination with the fluorescence guided resection surgical microscope (FGR-microscope), and evaluate them in terms of diagnostic performance and practical aspects of fluorescence detection. Eighteen operations were performed on 16 patients with suspected high-grade glioma. The HHF-probe and the FGR-microscope were used for detection of protoporphyrin (PpIX) fluorescence induced by 5-aminolevulinic acid (5-ALA) and evaluated against histopathological analysis and visual grading done through the FGR-microscope by the surgeon. A ratio of PpIX fluorescence intensity to the autofluorescence intensity (fluorescence ratio) was used to quantify the spectra detected by the probe. Fluorescence ratio medians (range 0 - 40) measured by the probe were related to the intensity of the fluorescence in the FGR-microscope, categorized as "none" (0.3, n=131), "weak" (1.6, n=34) and "strong" (5.4, n=28). Of 131 "none" points in the FGR-microscope, 88 (67%) exhibited fluorescence with the HHF-probe. For the tumor marginal zone, the area under the receiver operator characteristics (ROC) curve was 0.49 for the FGR-microscope and 0.65 for the HHF-probe. The probe was integrated in the established routine of tumor resection using the FGR-microscope. The HHF-probe was superior to the FGR-microscope in sensitivity; it detected tumor remnants after debulking under the FGR-microscope. The combination of the HHF-probe and the FGR-microscope was beneficial especially in the tumor marginal zone. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Primary Endobronchial Marginal Zone B-Cell Lymphoma of Bronchus-Associated Lymphoid Tissue: CT Findings in 7 Patients (United States)

    Yoon, Ra Gyoung; Song, Jae Woo; Chae, Eun Jin; Choi, Chang Min; Jang, SeJin


    Objective To investigate CT and 18F-flurodeoxyglucose (18F-FDG) positron-emission tomography/CT findings of primary endobronchial marginal zone B-cell lymphoma of the bronchus-associated lymphoid tissue (BALT). Materials and Methods From June 2006 through April 2012, seven patients (six female, one male; age range, 21-61 years; mean age, 49 years) were examined who were pathologically diagnosed with the primary endobronchial marginal zone B-cell lymphoma of BALT. We evaluated the locations and characteristics of the lesions on CT and 18F-FDG-PET/CT scans. The lesions were classified into the following three patterns: 1) solitary intraluminal nodule; 2) several tiny nodular protrusions; and 3) diffuse wall thickening. Results A solitary intraluminal nodule was observed in four patients (57.1%), several tiny nodular protrusion in two patients (28.6%), and diffuse wall thickening in one patient (14.3%). The lesions were categorized into 3 major locations: confined to the trachea (n = 3), confined to the lobar bronchus (n = 2), and diffuse involvement of the trachea and both main bronchi (n = 2). All lesions demonstrated homogeneous iso-attenuation as compared with muscle on pre- and post-enhancement scans. Secondary findings in the lungs (n = 3; 42.9%) included postobstructive lobar atelectasis (n = 1), air trapping (n = 1), and pneumonia (n = 1). On 18F-FDG-PET/CT (n = 5), 4 lesions showed homogeneous uptake with maximum standardized uptake values (mSUV), ranging 2.3-5.7 (mean mSUV: 3.3). One lesion showed little FDG uptake. Conclusion Primary endobronchial marginal zone B-cell lymphoma of the BALT manifests as three distinct patterns on CT, with the solitary intraluminal nodule presenting as the main pattern. Most lesions demonstrate homogeneous but weak FDG uptake on 18F-FDG-PET/CT. PMID:23483549

  9. Primary endobronchial marginal zone B-cell lymphoma of bronchus-associated lymphoid tissue: CT findings 7 patients

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Ra Gyoung; Kim, Mi Young; Song, Jae Woo; Chae, Eun Jin; Choi, Chang Min; Jang, Se Jin [University of Ulsan College of Medicine, Seoul (Korea, Republic of)


    To investigate CT and 1{sup 8F}-fluorodeoxyglucose (1{sup 8F}-FDG) positron-emission tomography/CT findings of primary endobronchial marginal zone B-cell lymphoma of the bronchus-associated lymphoid tissue (BALT). From June 2006 through April 2012, seven patients (six female, one male; age range, 21-61 years; mean age, 49 years) were examined who were pathologically diagnosed with the primary endobronchial marginal zone B-cell lymphoma of BALT. We evaluated the locations and characteristics of the lesions on CT and 1{sup 8F}-FDG-PET/CT scans. The lesions were classified into the following three patterns: 1) solitary intraluminal nodule; 2) several tiny nodular protrusions; and 3) diffuse wall thickening. A solitary intraluminal nodule was observed in four patients (57.1%), several tiny nodular protrusion in two patients (28.6%), and diffuse wall thickening in one patient (14.3%). The lesions were categorized into 3 major locations: confined to the trachea (n 3), confined to the lobar bronchus (n = 2), and diffuse involvement of the trachea and both main bronchi (n = 2). All lesions demonstrated homogeneous iso-attenuation as compared with muscle on pre- and post-enhancement scans. Secondary findings in the lungs (n = 3; 42.9%) included postobstructive lobar atelectasis (n = 1), air trapping (n = 1), and pneumonia (n = 1). On 1{sup 8F}-FDG-PET/CT (n = 5), 4 lesions showed homogeneous uptake with maximum standardized uptake values (mSUV), ranging 2.3-5.7 (mean mSUV: 3.3). One lesion showed little FDG uptake. Primary endobronchial marginal zone B-cell lymphoma of the BALT manifests as three distinct patterns on CT, with the solitary intraluminal nodule presenting as the main pattern. Most lesions demonstrate homogeneous but weak FDG uptake on 1{sup 8F}-FDG-PET/CT.


    Directory of Open Access Journals (Sweden)



    Full Text Available The Late Jurassic-Early Cretaceous Apulia platform margin and the transition to adjacent basinal deposits (inner platform to basin are well exposed in the Gargano Promontory. Detailed field work has allowed to recognize eight main facies associations which reflect various depositional environments, and which document a differentiated zonation, from the inner platform to the basin. A shallow lagoon existed in the internal part of the Gargano Promontory with a transition to tidal flat areas (F1. Oolitic shoals (F2 bordered this internal peritidal area passing seaward to a reef-flat with abundant corals (F3. A reef-front, associated with a coral rubble zone, has been found in some areas (F4. In the external margin zone, massive wackestones with Ellipsactinia occur (F5 and pass gradually to a rudstone facies on the proximal slope (F6. The base-of-slope facies association consists of pelagic sediments interbedded with gravity-displaced deposits (F7 and F8. The depositional profile of the Apulia Platform is typical of the Tethyan Jurassic-Early Cretaceous platforms, with slope declivities in the order of 25°-28°. The remarkable progradation of the platform in the northern tract of the Gargano (Lesina and Varano lakes area and its substantial stability east- and southwards (Mattinata area suggest a possible windward position of the margin in this latter portion and, in contrast, a leeward position of the northern portion.   

  11. Late Cretaceous crinoids (Echinodermata) from the southwestern margin of the Holy Cross Mts. (southern Poland) and phylogenetic relationships among bourgueticrinids. (United States)

    Lach, Rafał; Salamon, Mariusz A


    A systematic account of crinoids from the Upper Coniacian-Lower Campanian of the southwestern margin of the Holy Cross Mountains in southern Poland is presented. Seven crinoid taxa [Marsupites testudinarius (von Schlotheim), Bourgueticrinus ellipticus (Miller), Bourgueticrinus sp., I.? granosus Valette, Isocrinus? sp., Nielsenicrinus carinatus Roemer and Austinocrinus bicoronatus (von Hagenow)] are described and illustrated. The new material from Poland extends down the stratigraphic range of Austinocrinus bicoronatus to the Lower Campanian. Morphometric data support that Bourgueticrinus ellipicus and B.? suedicus are conspecific. Taphonomy and paleoecology of recorded crinoid assemblages are discussed. Phylogeny of Cretaceous bourgueticrinids is also revisited.

  12. Strong depth-related zonation of megabenthos on a rocky continental margin (∼700-4000 m) off southern Tasmania, Australia

    National Research Council Canada - National Science Library

    Thresher, Ronald; Althaus, Franziska; Adkins, Jess; Gowlett-Holmes, Karen; Alderslade, Phil; Dowdney, Jo; Cho, Walter; Gagnon, Alex; Staples, David; McEnnulty, Felicity; Williams, Alan


    Assemblages of megabenthos are structured in seven depth-related zones between ∼700 and 4000 m on the rocky and topographically complex continental margin south of Tasmania, southeastern Australia...


    Directory of Open Access Journals (Sweden)

    K. Zh. Seminsky


    Full Text Available The zone-block structure of the lithosphere is represented by a hierarchically organized pattern of stable blocks and mobile zones which border such blocks and contain highly dislocated geological medium (Fig. 1. Today, different specialists adhere to different concepts of blocks and zones, which are two main elements of the lithosphere structure. Differences are most significant in determinations of ‘interblock zones’ that are named as deformation / destructive / contact / mobile / fracture zones etc. due to their diversity in different conditions of deformation. One of the most effective approaches to studying the zone-block structure of the lithosphere is a combination of geological and geophysical studies of interblock zones tectonic features on various scales, which can make it possible to reveal the most common patterns of the interblock zones, general regularities of their development and relationships between the interblock zones.The main objectives of our study were (1 to identify the zone-block structure of the crust in the southern regions of East Siberia from tectonophysical analysis of geological and geophysical surveys conducted on four different scales along the 500 km long Shertoy-Krasny Chikoy transect crossing the marginal segment of the Siberian block, the Baikal rift and the Transbaikalian block (Fig. 2; (2 to clarify structural features of the central part of the Baikal rift (representing the tectonic type of interblock extension zone by applying new research methods, such as radon emanation survey, to the Shertoy-Krasny Chikoy transect and using the previously applied methods, such as magnetotelluric sounding, on a smaller scale; and (3 to study manifestation of interblock zones of various ranks in different geological and geophysical fields, to reveal common specific features of their structural patterns for the upper crust, and to establish regularities of hierarchic and spatial relationships between the interblock

  14. Early Ordovician conodonts from the Sakmara Zone of the Southern Urals) and their biogeography (United States)

    Tolmacheva, T. Yu.; Ryazantsev, A. V.


    The new data obtained on conodonts from the Lower Ordovician of the Kidryasovo, Akbulaksai, and Kuagach formations (the central part of the Sakmara Zone of the Southern Urals) allow to evaluate the biogeography of conodonts of this region. The comparison of conodont assemblages of the Southern Urals with well-studied conodont assemblages of the Baltoscandian Basin situated in the northwestern part of the East European Platform show that these assemblages were biogeographically isolated. This shows that basins of the central and eastern parts of the East European Platform were separated by land in the Early Ordovician.

  15. The configuration of the seismic zone and the downgoing slab in southern Peru


    Grange, F.; Cunningham, P.; Gagnepain, J.; Hatzfeld, D.; Molnar, P.; L. Ocola; Rodrígues, A.; S. W. Roecker; Stock, J. M.; Suárez, G


    Using data from temporary networks of portable seismographs in southern Peru, we located 888 shallow and intermediate depth events near a proposed discontinuity in the seismic zone there. These events reveal a prominent contortion, instead of a discontinuity, that trends approximately N80°E, parallel to the direction of relative plate motion. North of about 15°S, the seismic zone beneath Peru is nearly horizontal, but south of about 15.5°S, it dips at about 25°. Volcanoes lie above the more s...


    Directory of Open Access Journals (Sweden)


    Full Text Available ABSTRACT Pear is among the fruits of major commercial interest in the world and one of the most imported in Brazil. Brazilian production is very small and the fruit quality is low, due to production problems. The success of culture in the country, among other factors, may be linked to the choice of cultivars, pollinating and rootstocks better adapted to local conditions, and thus depend on the particulars of an agricultural zoning. The aim of this study was to identify, in southern Brazil, homogeneous climatic zones with potential for growing of European and Asian pears, through climate risk studies. The regions were defined by the seasonal availability of chilling hours (<7.2 °C accumulated during the period from May to September and the monthly risk of drought. The analysis allowed the recognition of four homogeneous areas for the production of pears in southern Brazil.

  17. A sea ice model for the marginal ice zone with an application to the Greenland Sea

    DEFF Research Database (Denmark)

    Pedersen, Leif Toudal; Coon, Max D.


    A model is presented that describes the formation, transport, and desalinization of frazil and pancake ice as it is formed in marginal seas. This model uses as input the total ice concentration evaluated from Special Sensor Microwave Imager and wind speed and direction. The model calculates...... the areal concentration, thickness, volume concentration, and salinity of frazil ice as well as the areal concentration, thickness, and salinity of pancakes. A simple parameterization for the Odden region of the Greenland Sea is presented. The model is run for the winter of 1996-1997. There are direct...... observations of the thickness and salinity of pancakes and the volume concentration of frazil ice to compare with the model. The model results compare very well with the measured data. This new ice model can be tuned to work in marginal seas elsewhere to calculate ice thickness, motion, and brine rejection...

  18. Enhanced expression of Pafah1b1 causes over-migration of cerebral cortical neurons into the marginal zone. (United States)

    Katayama, Kei-Ichi; Hayashi, Kanehiro; Inoue, Seika; Sakaguchi, Kazushige; Nakajima, Kazunori


    Mutations of PAFAH1B1 cause classical lissencephaly in humans. In addition, duplications and triplications of PAFAH1B1 are found in individuals with intellectual disability and other neurological disorders suggesting that proper brain development is highly sensitive to the PAFAH1B1 dosage. To examine the effect of PAFAH1B1 over-dosage in neural development, especially in migration of neurons and layer formation during cerebral cortical development, we overexpressed Pafah1b1 in migrating neurons in the mouse embryonic cortex using in utero electroporation. Enhanced expression of Pafah1b1 in radially-migrating neurons resulted in their over-migration into the marginal zone. Neurons that invaded the marginal zone were oriented abnormally. Layer distribution of Pafaha1b1-overexpressing neurons shifted more superficially than control neurons. Some of the Pafaha1b1-overexpressing future layer 4 neurons changed their positions to layers 2/3. Furthermore, they also changed their layer marker expression from layer 4 to layers 2/3. These results suggest that overexpression of Pafah1b1 affects the migration of neurons and disrupts layer formation in the developing cerebral cortex, and further support the idea that appropriate dosage of Pafah1b1 is crucial for the proper development of the brain.

  19. Deglacial changes in the strength of deep southern component water and sediment supply at the Argentine continental margin (United States)

    Warratz, Grit; Henrich, Rüdiger; Voigt, Ines; Chiessi, Cristiano M.; Kuhn, Gerhard; Lantzsch, Hendrik


    The deep southern component water (SCW), comprising Lower Circumpolar Deep Water (LCDW) and Antarctic Bottom Water (AABW), is a major component of the global oceanic circulation. It has been suggested that the deep Atlantic water mass structure changed significantly during the last glacial/interglacial cycle. However, deep SCW source-proximal records remain sparse. Here we present three coherent deep SCW paleocurrent records from the deep Argentine continental margin shedding light on deep water circulation and deep SCW flow strength in the Southwest Atlantic since the Last Glacial Maximum (LGM). Based on increased sortable silt values, we propose enhanced deep SCW flow strength from 14 to 10 cal ka B.P. relative to the early deglacial/LGM and the Holocene. We propose a direct influence of deep northern component water (NCW) on deep SCW flow strength due to vertical narrowing of deep SCW spreading, concurrent with a migration of the high-energetic LCDW/AABW interface occupying our core sites. We suggest a shoaled NCW until 13 cal ka B.P., thereby providing space for deep SCW spreading that resulted in reduced carbonate preservation at our core sites. Increased carbonate content from 13 cal ka B.P. indicates that the NCW expanded changing deep water properties at our core sites in the deep Southwest Atlantic. However, southern sourced terrigenous sediments continued to be deposited at our core sites, suggesting that deep SCW flow was uninterrupted along the Argentine continental margin since the LGM.

  20. Ins and outs of a complex subduction zone: C cycling along the Sunda margin, Indonesia (United States)

    House, B. M.; Bebout, G. E.; Hilton, D. R.


    Subduction of C in marine sediments and altered oceanic crust is the main mechanism for reintroducing C into the deep earth and removing it from communication with the ocean and atmosphere. However, detailed studies of individual margins - which are necessary to understanding global C cycling - are sparse. The thick, C-rich sediment column along the Sunda margin, Indonesia makes understanding this margin crucial for constructing global C cycling budgets. Furthermore it is an ideal location to compare cycling of organic and carbonate C due to the abrupt transition from carbonate-dominated sediments in the SE to sediments rich in organic C from the Nicobar Fan in the NW. To quantify and characterize C available for subduction, we analyzed samples from DSDP 211, 260, 261, and ODP 765, all outboard of the trench, as well as piston and gravity cores of locally-sourced terrigenous trench fill. We created a 3-D model of overall sediment thickness and the thicknesses of geochemically distinct sedimentary units using archived and published seismic profiles to infer unit thicknesses at and along the 2500 km trench. This model vastly improves estimates of the C available for subduction and also reveals that the Christmas Island Seamount Province serves as a barrier to turbidite flow, dividing the regions of the trench dominated by organic and inorganic C input. Incorporating best estimates for the depth of the decollement indicates that the terrigenous trench fill, with up to 1.5 wt % organic C, is entirely accreted as is the thick section of carbonate-rich turbidites that dominate the southeastern portion of the margin (DSDP 261/ODP 765). Organic C accounts for most of the C bypassing the accretionary complex NW of the Christmas Island Seamount Province, and C inputs to the trench are lower there than to the SE where carbonate units near the base of the sediment column are the dominant C source. Release of C from altered oceanic crust - a C reservoir up to 10 times greater

  1. In situ measurements of thermal diffusivity in sediments of the methane-rich zone of Cascadia Margin, NE Pacific Ocean

    Directory of Open Access Journals (Sweden)

    Kira Homola


    Full Text Available Abstract Thermal diffusivity (TD is a measure of the temperature response of a material to external thermal forcing. In this study, TD values for marine sediments were determined in situ at two locations on the Cascadia Margin using an instrumented sediment probe deployed by a remotely operated vehicle. TD measurements in this area of the NE Pacific Ocean are important for characterizing the upslope edge of the methane hydrate stability zone, which is the climate-sensitive boundary of a global-scale carbon reservoir. The probe was deployed on the Cascadia Margin at water depths of 552 and 1049 m for a total of 6 days at each site. The instrumented probe consisted of four thermistors aligned vertically, one sensor exposed to the bottom water and one each at 5, 10, and 15 cm within the sediment. Results from each deployment were analyzed using a thermal conduction model applying a range of TD values to obtain the best fit with the experimental data. TD values corresponding to the lowest standard deviations from the numerical model runs were selected as the best approximations. Overall TDs of Cascadia Margin sediments of 4.33 and 1.15 × 10–7 m2 s–1 were calculated for the two deployments. These values, the first of their kind to be determined from in situ measurements on a methane hydrate-rich continental margin, are expected to be useful in the development of models of bottom-water temperature increases and their implications on a global scale.

  2. Diagenetic paths in the margin of a Triassic Basin: NW zone of the Iberian Chain, Spain (United States)

    Ochoa, Maria; Arribas, José


    Buntsandstein deposits generated in a slowly subsiding basin on the western margin of the Iberian Chain are represented by a stratigraphic succession of fluvial deposits less than 100 m thick (conglomerates, sandstones, and shales). Diagenetic processes in sandstones can be grouped as eodiagenetic, mesodiagenetic, and telodiagenetic. Eodiagenesis can be associated with Muschelkalk, Keuper, and probably early Jurassic times. Mesodiagenesis is probably related to Jurassic times. Diagenetic chemical reactions suggest a maximum burial less than 1.5 km and low temperatures (mean, 30%). Type II sandstones are characterized by high compactional porosity loss and exhibit low values of intergranular volume (mean, 16.9%). Type II sandstones are associated with the dissolution of cement and later re-compaction of type I sandstones. An intermediate telodiagenetic phase is deduced and related to the sharp unconformity between Lower Cretaceous sediments and the underlying sediments. This suggests that a mechanically unstable framework collapsed during the Cretaceous, generating type II sandstones. The analyzed diagenetic paths have a wide applicability on similar marginal areas of rift basins.

  3. Tectonics and geochronology of the northern margin of the Zhongba terrane, Southern Tibet: implications for the closing processes of the western Neo-Tethys (United States)

    Liu, Q.; Li, S.; DONG, Y.; Han, G.


    The Zhongba terrane represents a special tectonic unit sitting between the northern and the southern ophiolitic sub-belt in the western segment of the Yarlung Zangbo Suture Zone (YZSZ), which separates the Indian and the Eurasian continental plates. The central-east section of the Zhongba terrane can be divided into fault-fold belt, fold belt and fault belt. The fault-fold belt, composed of northward-dipping thrust faults and asymmetric folds in the Carboniferous and late Devonian strata, mainly occurs at the northern margin of the Zhongba terrane. Four stages of deformation (D1-D4) can be recognized in this belt. Stage D1 is recorded by the rolling folds in the Devonian strata in which the residual S0 can be observed in asymmetric small folds. Quartz c-axis fabrics show that the dominant slip system of quartz is basal under transpression and low temperature (~ 400℃). In the stage D2, many small folds with axial plane inclined at high angle to the north were formed. The highly inclined C foliation in mylonitic limestones suggests that this belt represents the strain concentration zone during the northward subduction of the Neo-Tethyan lithosphere beneath the Gangdese arc belt. Coaxial progressive deformation is demonstrated by strongly shortened layers and abundant cleavages that are parallel to the axial plane of pre-existing folds in the stage D3. Mylonitic foliation is replaced by the cleavages plane (S2) associated with southward thrusts. In the stage D4, some northward thrusts and relevant cleavage with medium angle replaced early folds. Zircon U-Pb ages found in nearby quartz diorites at Gangdese arc belt yielded 91.8 ± 1.3 Ma. Since these quartz diorites are compositionally similar to island-arc magma from active continental margins, we infer that the northward subduction of the north sub-belt of the YZSZ started in the upper Cretaceous. Muscovite separates from representative tectonites within the strain concentration zone and the southward thrust belts

  4. Macrofaunal community structure in the western Indian continental margin including the oxygen minimum zone

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Sautya, S.; Sivadas, S.; Singh, R.; Nanajkar, M.

    been reported from the low-oxygen zone in a basin off Peru with partially laminated sediments (Levin et al. 2002). During the present study, macrofaunal diversity was generally higher at shelf and basin sites than on the slope reflecting the lower.... (1997) The Tanaidacea. In: J.A. Blake., P.H. Scott (Eds). Taxonomic Atlas of the Benthic Fauna of the Santa Maria Basin and western Santa Barbara Channel, Santa Barbara Museum of Natural History, Santa Barbara,181–278 Chapter 11: The Crustacea, Part 2...

  5. A coupled dynamic-thermodynamic model of an ice-ocean system in the marginal ice zone (United States)

    Hakkinen, Sirpa


    Thermodynamics are incorporated into a coupled ice-ocean model in order to investigate wind-driven ice-ocean processes in the marginal zone. Upswelling at the ice edge which is generated by the difference in the ice-air and air-water surface stresses is found to give rise to a strong entrainment by drawing the pycnocline closer to the surface. Entrainment is shown to be negligible outside the areas affected by the ice edge upswelling. If cooling at the top is included in the model, the heat and salt exchanges are further enhanced in the upswelling areas. It is noted that new ice formation occurs in the region not affected by ice edge upswelling, and it is suggested that the high-salinity mixed layer regions (with a scale of a few Rossby radii of deformation) will overturn due to cooling, possibly contributing to the formation of deep water.

  6. Is bone marrow biopsy always indicated in patients with primary cutaneous marginal zone B-cell lymphoma? (United States)

    Muniesa, C; Hernández-Machín, B


    Bone marrow involvement at the time of diagnosis is uncommon in patients with primary cutaneous marginal zone B-cell lymphoma (PCMZL). Moreover, in these patients such involvement is rarely found in isolation on diagnosis. Typically the few patients with PCMZL who have early bone marrow involvement also present secondary nodal or visceral involvement, which is detected by other staging studies (usually computed tomography). In recent years, this has given rise to some debate about whether a bone marrow biopsy should be routinely performed in patients diagnosed with PCMZL in view of the good prognosis and low incidence of bone marrow infiltration and/or extracutaneous involvement in this type of lymphoma. Copyright © 2012 Elsevier España, S.L. and AEDV. All rights reserved.

  7. Extranodal marginal zone B cell lymphoma: An unexpected complication in children with Sjögren's syndrome. (United States)

    Collado, Paz; Kelada, Aml; Cámara, Maria; Zeft, Andrew; Flagg, Aron


    Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by the infiltration of lymphocytes into exocrine glands, resulting in the typical sicca symptoms. Unlike adults, primary SS is a very rare condition in childhood, and the risk of malignancy in juvenile SS (JSS) has not been defined. We report the detection of extranodal marginal zone B-cell lymphoma (EMZL) occurring in two children with SS. Fine needle aspiration of the salivary glands (SG) showed nonspecific findings that led to delayed diagnosis of SS. The diagnosis of B-cell lymphoma associated with JSS was based on morphologic and immunohistochemical staining done during the biopsy. To highlight awareness of EMZL as a timely and appropriate update of an unusual complication in children with SS. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  8. Bilateral Bronchiectasis as a Presentation Form of Pulmonary Marginal Zone B-Cell Lymphoma of Bronchus Associated Lymphoid Tissue

    Directory of Open Access Journals (Sweden)

    Glenda Ernst


    Full Text Available The pulmonary marginal zone B-cell lymphoma of bronchus associated lymphoid tissue of the lung (BALT is a rare illness that can remain without symptoms. Radiological findings of pulmonary lymphoma are heterogeneous. In literature, bronchiectasis is only described in one patient who also had besides adenomegalies. We reported on a 48-year-old female patient. She showed symptoms consistent with dyspnea with productive cough; there were crepitant sounds in the auscultation. Pulmonary functional test has shown a severe restrictive pattern with a low FVC and DLCO. CT scan showed bronchiectasis in the medium lobule without adenomegalies. Echocardiogram was normal, and the laboratory findings only showed leukocytosis. There were no findings in the bronchoscopy, but the lung biopsy showed a B-cell pulmonary lymphoma (positive to CD20 and CD79a in immunostaining. A wide variety of radiological manifestations has been previously described; however, we have presented this rare case, with bronchiectasis, as unique radiological finding.

  9. A new interpretation for the interference zone between the southern Brasília belt and the central Ribeira belt, SE Brazil (United States)

    Trouw, Rudolph A. J.; Peternel, Rodrigo; Ribeiro, Andre; Heilbron, Mônica; Vinagre, Rodrigo; Duffles, Patrícia; Trouw, Camilo C.; Fontainha, Marcos; Kussama, Hugo H.


    In southeastern Brazil, the Neoproterozoic NNW-SSE trending southern Brasília belt is apparently truncated by the ENE-WSW central Ribeira belt. Different interpretations in the literature of the transition between these two belts motivated detailed mapping and additional age dating along the contact zone. The result is a new interpretation presented in this paper. The southern Brasília belt resulted from E-W collision between the active margin of the Paranapanema paleocontinent, on the western side, now forming the Socorro-Guaxupé Nappe, with the passive margin of the São Francisco paleocontinent on the eastern side. The collision produced an east vergent nappe stack, the Andrelândia Nappe System, along the suture. At its southern extreme the Brasília belt was thought to be cut off by a shear zone, the "Rio Jaguari mylonites", at the contact with the Embu terrane, pertaining to the Central Ribeira belt. Our detailed mapping revealed that the transition between the Socorro-Guaxupé Nappe (Brasília belt) and the Embu terrane (Ribeira belt) is not a fault but rather a gradational transition that does not strictly coincide with the Rio Jaguari mylonites. A typical Cordilleran type magmatic arc batholith of the Socorro-Guaxupé Nappe with an age of ca. 640 Ma intrudes biotite schists of the Embu terrane and the age of zircon grains from three samples of metasedimentary rocks, one to the south, one to the north and one along the mylonite zone, show a similar pattern of derivation from a Rhyacian source area with rims of 670-600 Ma interpreted as metamorphic overgrowth. We dated by LA-MC-ICPMS laser ablation (U-Pb) zircon grains from a calc-alkaline granite, the Serra do Quebra-Cangalha Batholith, located within the Embu terrane at a distance of about 40 km south of the contact with the Socorro Nappe, yielding an age of 680 ± 13 Ma. This age indicates that the Embu terrane was part of the upper plate (Socorro-Guaxupé Nappe) by this time. Detailed mapping

  10. The January 25th, 2014 Kebumen earthquake: A normal faulting in subduction zone of Southern Java (United States)

    Serhalawan, Yopi Ruben; Sianipar, Dimas; Suardi, Iman


    Normal faulting mechanism of earthquake in subduction zone is quite interested to study further. We investigated the Kebumen, January 25, 2014 earthquake sequences by retrieving focal mechanisms using full moment tensor inversion. We used BMKG seismic data from stations in the vicinity of Central Java region for these inversions. Then we correlated the static coulomb stress change by the mainshock to the aftershocks. We found that mainshock is a normal faulting earthquake with nodal plane 1; strike 283, dip 22 and rake -100; nodal plane 2 with strike 113, dip 68 and rake -86. Using distribution analysis of high precision aftershocks after relocated; we considered that the reliable fault plane was nodal plane 1 with strike trending SE-NW. The focal mechanisms provide an estimate of the local stress field in the Wadati-Beniof Zone of Southern Java subduction zone. There is also conclution stating that the mainshock may trigger the aftershocks mainly in three zones, i.e. in continental crustal, upper mantle and on the oceanic slab. This is visually showed that the high quality aftershocks located in positive zones of static coulomb stress change.

  11. A Experimental Study of the Coherent Under-Ice Reflectivity of Sound in the Greenland Sea Marginal Ice Zone. (United States)

    Gruber, Patricia L.


    The coherent component of acoustic under-ice reflectivity was investigated as a function of frequency and grazing angle in the Marginal Ice Zone (MIZ). Measured reflectivity was compared with predictions by scattering theories to test the hypothesis of ridge scattering dominance in the MIZ. Explosive source acoustic signals were received on a vertical array, during the Marginal Ice Zone Experiment (MIZEX 84), and deconvolved to separate the direct and surface-reflected arrivals. Data was available from multiple days and ranges, resulting in an ensemble of ice-scattered measurements. The surface arrivals were aligned in time and coherently averaged over grazing angle for frequency bins from 64 to 256 Hz. Coherent reflectivity decreased with grazing angle from 12^circ to 35^circ and with frequency from 64 to 256 Hz. Remote sensing data, taken during the experiment, showed that the ice cover was primarily composed of small floes (ice-surface height measurements were analyzed to infer a pressure ridge sail height distribution or surface rms roughness for input to corresponding scattering theories. The measured reflectivity was compared with reflectivity from smooth elastic plate theory, perturbation theory for a rough pressure release surface, perturbation theory for a rough elastic surface, and Burke-Twersky theory for hard and soft, infinite, semi-elliptical cylinders on a soft plane. Perturbation theories were limited to the low frequencies (sail ratio of 6.5 was assumed. The data-theory comparison suggested that under-ice scattering in the MIZ, at angles less than 30 ^circ, and frequencies less than 256 Hz, is dominated by ridge-like scattering which depends on the geometric rather than the physical properties of the ice.

  12. CD5-positive marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT of the lung

    Directory of Open Access Journals (Sweden)

    Terada Tadashi


    Full Text Available Abstract CD5-positive marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT of the lung is very rare. An 82-year-old Japanese woman was found to have an abnormal lung shadow on chest X-ray photography, and was admitted to our hospital. Imaging modalities including X-ray photography, computed tomography, and magnetic resonance imaging showed a small (2 × 1 × 1 cm opacity of the right upper lobe. Transbronchial lung biopsy was performed. It showed severe proliferation of small lymphocytes. The small lymphocytes were centrocytes-like, and minor plasma cell differentiation was recognized. Lymphoepithelial lesions were scattered. Immunohistochemically, the tumor cells were positive for CD5, CD20, CD43, CD45, CD79α, bcl-2, and κ-chain, but negative for CD2, CD3, CD10, CD21, CD23, CD35, CD45RO, CD56, IgA, IgG, IgM, IgD, λ-chain, TdT, and cyclin D1. The Ki-67 labeling was 10%. CD3-positive and CD45RO-positive inflammatory T-cells were scattered in small amount. The pathological diagnosis was CD5-positive marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT of the lung. The patient was treated with chemotherapy (CHOP: cyclophosphamide, hydroxydaunorbicin, vincristine, and predonisone, and the lung tumor disappeared. The patient is now free of the lymphoma 10 years after the first manifestation. Virtual slides The virtual slide(s for this article can be found here:

  13. Two new species and a new record of Comesomatidae (Nematoda, Araeolaimida) from Southern Hikurangi Margin, New Zealand. (United States)

    Rosli, Norliana; Leduc, Daniel; Probert, P Keith


    We describe two new species and provide one new species record of the family Comesomatidae from a submarine canyon habitat on the Southern Hikurangi margin, New Zealand. Vasostoma hexodontium n. sp. is characterized by having an amphideal fovea with three turns, buccal cavity with six teeth and gubernaculum with long and straight caudal apophyses. Sabatieria dispunctata n. sp. is characterized by the absence of cuticle punctations, large amphideal fovea with 4.5 turns, pharynx with posterior bulb, absence of pre-cloacal supplements, strongly arcuate and cuticularized spicules, simple gubernaculum with short caudal apophyses, and vulva opening directed posteriorly. Laimella subterminata Chen & Vincx, 2000, which was originally described from the Beagle Channel and the Magellan Strait (Chile), is recorded from the Southwest Pacific for the first time. 

  14. Late Wisconsin periglacial environments of the southern margin of the Laurentide Ice Sheet reconstructed from pollen analyses (United States)

    Heusser, Linda; Maenza-Gmelch, Terryanne; Lowell, Thomas; Hinnefeld, Rebecca


    Full-glacial pollen assemblages from four radiocarbon-dated interstadial deposits in southwestern Ohio and southeastern Indiana imply the presence of herbaceous vegetation (tundra or muskeg with subarctic indicator Selaginella selaginoides) on the southern margin of the Miami lobe of the Laurentide Ice Sheet ca. 20 000 14C yr BP. Scattered Picea (spruce) and possibly Pinus (pine) may have developed regionally ca. 19 000 14C yr BP, and ca. 18 000 14C yr BP, respectively. Spruce stumps in growth position support a local source of pollen. Prior to the ca. 14 000 14C yr BP glacial advance, small amounts of Quercus (oak) and other deciduous pollen suggest development of regional boreal (conifer-hardwood) forests.

  15. Macrofaunal communities and sediment structure across the Pakistan margin Oxygen Minimum Zone, North-East Arabian Sea (United States)

    Hughes, David J.; Lamont, Peter A.; Levin, Lisa A.; Packer, Margaret; Feeley, Kathleen; Gage, John D.


    Benthic macrofauna and sediment column features were sampled at five stations along a bathymetric transect (depths 140, 300, 940, 1200, 1850 m) through the Pakistan margin Oxygen Minimum Zone (OMZ) during the 2003 intermonsoon (March-May) and late-post-monsoon (August-October) periods. Objectives were to compare patterns with those described from other OMZs, particularly the Oman margin of the Arabian Sea, in order to assess the relative influence of bottom-water oxygenation and sediment organic content on macrofaunal standing stock and community structure. Macrofaunal density was highest at the 140-m station subject to monsoon-driven shoaling of the OMZ, but there was no elevation of density at the lower OMZ boundary (1200 m). Numbers was extremely low in the OMZ core (300 m) and were not readily explicable from the environmental data. There was no consistent depth-related trend in macrofaunal biomass. Macrofaunal densities were consistently lower than found off Oman but there was less contrast in biomass. A significant post-monsoon decline in macrofaunal density at 140 m was driven by selective loss of polychaete taxa. Polychaeta was the most abundant major taxon at all stations but did not dominate the macrofaunal community to the extent reported from Oman. Cirratulidae and Spionidae were major components of the polychaete fauna at most stations but Acrocirridae, Ampharetidae, Amphinomidae and Cossuridae were more important at 940 m. Polychaete assemblages at each station were almost completely distinct at the species level. Polychaete species richness was positively correlated with bottom-water dissolved oxygen and negatively correlated with sediment TOC, C:N ratio and total phytopigments. Community dominance showed the opposite pattern. The strongly inverse correlation between oxygen and measures of sediment organic content made it difficult to distinguish their relative effects. The strongly laminated sediments in the OMZ core contrasted with the homogeneous

  16. Fire Regime in Marginal Jack Pine Populations at Their Southern Limit of Distribution, Riding Mountain National Park, Central Canada

    Directory of Open Access Journals (Sweden)

    Jacques C. Tardif


    Full Text Available In central Canada, long fire history reconstructions are rare. In a context where both anthropogenic and climate influences on fire regime have changed, Parks Canada has a mandate to maintain ecological integrity. Here we present a fire history derived from fire-scarred jack pine (Pinus banksiana Lamb. trees growing at their southern distribution limit in Riding Mountain National Park (RMNP. In Lake Katherine Fire Management Unit (LKFMU, a subregion within the park, fire history was reconstructed from archival records, tree-ring records, and charcoal in lake sediment. From about 1450 to 1850 common era (CE the fire return intervals varied from 37 to 125 years, according to models. During the period 1864–1930 the study area burned frequently (Weibull Mean Fire Intervals between 2.66 and 5.62 years; this period coincided with the end of First Nations occupation and the start of European settlement. Major recruitment pulses were associated with the stand-replacing 1864 and 1894 fires. This period nevertheless corresponded to a reduction in charcoal accumulation. The current fire-free period in LKFMU (1930–today coincides with RMNP establishment, exclusion of First Nations land use and increased fire suppression. Charcoal accumulation further decreased during this period. In the absence of fire, jack pine exclusion in LKFMU is foreseeable and the use of prescribed burning is advocated to conserve this protected jack pine ecosystem, at the southern margins of its range, and in the face of potential climate change.

  17. Natural History Study of Monoclonal B Cell Lymphocytosis (MBL), Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL), Lymphoplasmacytic Lymphoma (LPL)/Waldenstrom Macroglobulinemia (WM), and Splenic Marginal Zone Lymphoma (SMZL) (United States)


    B-Cell Chronic Lymphocytic Leukemia; Monoclonal B-Cell Lymphocytosis; Lymhoma, Small Lymphocytic; Chronic Lymphocytic Leukemia; Lymphoplasmacytic Lymphoma; Waldenstrom Macroglobulinemia; Splenic Marginal Zone Lymphoma

  18. Animated tectonic reconstruction of the Southern Pacific and alkaline volcanism at its convergent margins since Eocene times (United States)

    Eagles, Graeme; Gohl, Karsten; Larter, Robert D.


    An animated reconstruction shows South Pacific plate kinematics, in the reference frame of West Antarctica, between 55 Ma and the present-day. The ocean floor in the region formed due to seafloor spreading between the Antarctic, Pacific, Phoenix and Nazca plates (a plate formed by fragmentation of the Farallon plate early in Oligocene times). The Pacific-Antarctic Ridge remained fairly stable throughout this time, migrating relatively northwestwards, by various mechanisms, behind the rapidly-moving Pacific plate. The Nazca and Phoenix plates also moved quickly, but relatively towards the east or southeast, and were subducted in these directions beneath the South American and Antarctic plates. Segments of spreading centres forming at the trailing edges of the Nazca and Phoenix plates periodically collided with these subduction zones, resulting in the total destruction of the Nazca-Phoenix spreading centre and the partial destruction of the Nazca-Antarctica spreading centre (the Chile Ridge) and Antarctic-Phoenix Ridge, which ceased to operate shortly before its northeasternmost three segments could collide with the Antarctic margin. Following collision of segments of the Chile Ridge, parts of the Antarctic plate underwent subduction at the Chile Trench. After these collisions, slab windows should have formed beneath both the South American and Antarctic convergent margins, and the animation shows occurrences of alkaline volcanism that have been, or can newly be, related to them. Further occurrences of alkali basalts, at the margins of the Powell Basin and, more speculatively, James Ross Island, can be related to the formation of a slab window beneath them following the collision of segments of the South America-Antarctica spreading centre in the northwest Weddell Sea.

  19. Sone megafan: A non-Himalayan megafan of craton origin on the southern margin of the middle Ganga Basin, India (United States)

    Sahu, Sudarsan; Saha, Dipankar; Dayal, Shankar


    Researchers in the last few decades have focused on the fluvial megafans at the base of Himalayan foothills in the Ganga Basin. No major effort has so far been made to delineate any such large depositional environment at the base of the northern Indian peninsular craton at the distal parts of the basin. In this work, for the first time, we document a megafan, unusually created by the cratonic Sone River in the marginal plains south of the Ganga. The geomorphology of the megafan surface, distribution of palaeochannels, sedimentology, and areal extent of the megafan are described. The study also reconstructs the tectonic and palaeoclimatic conditions, which might have helped in sediment supply from the cratonic catchment areas of the Sone. We suggest tectonic control over the Sone River channel dynamics and development of the megafan. The oval- and fan-shaped, craton-derived sediment body covers an area of around 12,000 km2 in the marginal plains and about 9000 km2 in the central alluvium north of the Ganga River. The megafan is around 190 km long and 240 km wide. The mean slope of the megafan surface is 0.03°. An onlap of Himalayan sediments has occurred over the megafan at its toe parts caused by southward encroachment of the Ganga during the Holocene. The megafan sediments comprise brownish yellow fine to coarse sand and gravels with an admixture of carbonaceous nodules (kankars). The thickness of the megafan sediment, which directly overlies the Precambrian basement, varies from only a few meters in the south near the peninsular craton to 1000 m at the north in the central alluvial plain. The granular zones form prolific aquifer systems in an otherwise poor hydrogeological setting of the marginal plains.

  20. Morphotectonics of the Padul-Nigüelas Fault Zone, southern Spain

    Directory of Open Access Journals (Sweden)

    Jochen Hürtgen


    Full Text Available The Padul-Nigüelas Fault Zone (PNFZ is situated at the south-western mountain front of the Sierra Nevada (southern Spain in the Internal Zone of the Betic Cordilleras and belongs to a NW-SE trending system of normal faults dipping SW. The PNFZ constitutes a major tectonic and lithological boundary in the Betics, and separates the metamorphic units of the Alpujárride Complex from Upper Tertiary to Quaternary deposits. Due to recent seismicity and several morphological and geological indicators, such as preserved fault scarps, triangular facets, deeply incised valleys and faults in the colluvial wedges, the PNFZ is suspected to be a tectonically active feature of the south-eastern Granada Basin. We performed morphotectonic GIS analyses based on digital elevation models (DEM, cell size: 10 m to obtain tectonic activity classes for each outcropping segment of the PNFZ. We have determined the following geomorphic indices: mountain front sinuosity, stream-length gradient index, concavity index and valley floor width to height ratio. The results show a differentiation in the states of activity along the fault zone strike. The western and eastern segments of the PNFZ indicate a higher tectonic activity compared to the center of the fault zone. We discuss and critically examine the comparability and reproducibility of geomorphic analyses, concluding that careful interpretation is necessary, if no ground-truthing can be performed.

  1. Geomorphic evidence of Quaternary tectonics within an underlap fault zone of southern Apennines, Italy (United States)

    Giano, Salvatore Ivo; Pescatore, Eva; Agosta, Fabrizio; Prosser, Giacomo


    A composite seismic source, the Irpinia - Agri Valley Fault zone, located in the axial sector of the fold-and-thrust belt of southern Apennines, Italy, is investigated. This composite source is made up of a series of nearly parallel, NW-striking normal fault segments which caused many historical earthquakes. Two of these fault segments, known as the San Gregorio Magno and Pergola-Melandro, and the fault-related mountain fronts, form a wedge-shaped, right-stepping, underlap fault zone. This work is aimed at documenting tectonic geomorphology and geology of this underlap fault zone. The goal is to decipher the evidence of surface topographic interaction between two bounding fault segments and their related mountain fronts. In particular, computation of geomorphic indices such as mountain front sinuosity (Smf), water divide sinuosity (Swd), asymmetry factor (AF), drainage basin elongation (Bs), relief ratio (Rh), Hypsometry (HI), normalized steepness (Ksn), and concavity (θ) is integrated with geomorphological analysis, the geological mapping, and structural analysis in order to assess the recent activity of the fault scarp sets recognized within the underlap zone. Results are consistent with the NW-striking faults as those showing the most recent tectonic activity, as also suggested by presence of related slope deposits younger than 38 ka. The results of this work therefore show how the integration of a multidisciplinary approach that combines geomorphology, morphometry, and structural analyses may be key to solving tectonic geomorphology issues in a complex, fold-and-thrust belt configuration.

  2. Thin-skinned gravitational transfer zone in the Southern part of Santos basin

    Energy Technology Data Exchange (ETDEWEB)

    Demercian, Luis Santiago; Szatmari, Peter [PETROBRAS, Rio de Janeiro, RJ (Brazil)


    The sedimentary sequence of the Santos Basin is structured mainly by salt tectonics, with limited contribution of basement involved tectonics. The ductility of the salt, which permits it to flow at low pressures and temperatures, is well known; interaction between the ductile behavior o the salt and the brittle behavior of the overlying sediments controls salt tectonics. Gliding and gravity spreading over the salt produce a good variety of structures such as listric faults with rollovers, salt walls, folds and thrusts. These structures are not evenly distributed in the Santos Basin but define distinct Salt Tectonic Provinces (Demercian and Szatmari, 1993; Demercian and Szatmari, 1993; Demercian, 1993), each with its characteristic pattern of flow and structure. The limits between these Provinces are always parallel to the main direction of flow at that location; they are nearly and abrupt, satisfying the criteria of transfer zones. Three such transfer zones have been defined: those of Ilha Grande, Merluza, and Tubarao. Below we are going to focus on the Tubarao Transfer Zone that divides the Southern and Southwestern Provinces of the basin (S and SW). It os worth nothing that our interest in identifying and analyzing these transfer zones derived from their providing long, nearly vertical fault planes which may act as important pathways in hydrocarbon migration and hence deserve the attention of explorationists. (author)

  3. Medicine on the margins: perspectives of abortion operating surgeons in southern New Zealand. (United States)

    Haslett, L; Barnett, P


    This research surveys operating surgeon perspectives on their work with a view to providing information relevant to improving access to abortion services. In depth interviews were held with 14 abortion operating surgeons in the southern region. Interviews were transcribed and analysed according to emergent themes. Operating surgeons reported their work as technically uninteresting but felt an obligation to provide a safe service and derived important satisfaction from helping patients. They valued peer support in the workplace and did not feel isolated from colleagues or lacking professional status. They noted that the introduction of medical abortions would provide opportunities to improve access. Mainstreaming abortions into other gynaecology services might improve the work environment for operating surgeons and training opportunities for doctors. Increased use of medical abortion techniques, may encourage doctors to become operating surgeons and improve access to services in some localities.

  4. Influences of temperature and environmental variables on the distribution of bull trout within streams at the southern margin of its range (United States)

    J. Dunham; B. Rieman; G. Chandler


    The bull trout Salvelinus confluentus is believed to be among the most thermally sensitive species in coldwater habitats in western North America. We conducted a comprehensive field assessment of thermal habitat associations throughout the southern margin of the species' range. We developed models of thermal habitat associations using two data sets representing a...

  5. Magnetotelluric Study of the Southern Margin of the Capricorn Orogen, Western Australia (United States)

    Piña-Varas, P.; Dentith, M. C.


    We present the current status and the preliminary results of a magnetotelluric (MT) study that is being performed in the Capricorn Orogen, in northern Western Australia. This project is a component of large multi-disciplinary geoscience project on the 'Distal Footprints of Giant Ore Systems'. The Capricorn Orogen, a largely Proterozoic orogenic belt, is being used as a natural laboratory to develop methods for exploring for mineral deposits 'under cover'. The MT dataset consists of a total of 240 broadband magnetotelluric stations (BBMT) and 84 long period stations (LMT). Analysis of the dataset reveals the area to have complex 3-D variations in electrical conductivity, making 3-D interpretation methods essential. The first 3-D inversion model encompasses south-eastern part of the Capricorn Orogen (Padbury-Bryah Basins) and the adjoining Yilgarn Craton, and involves the inversion of 58 BBMT sites. The results shown a prominent resistive feature that is tentatively correlated with the northern boundary of the Yilgarn Craton. Apart from this, the other main geoelectrical feature is a high conductivity body located within the Yilgarn Craton. This structure could be related to tectonic features associated with the accretion of the different terranes composing this part of the craton. Forward models were used to validate these and other structures. Major faults occurring at cratonic margins are known to be important indicators of increased prospectivity and our preliminary results suggest MT surveys are a useful tool for regional scale exploration in the study area.

  6. Biodiversity and spatial distribution of medusae in the Magellan Region (Southern Patagonian Zone

    Directory of Open Access Journals (Sweden)

    Sergio Palma


    Full Text Available Epipelagic medusae collected in the Magellan Region (Southern Patagonian Zone during spring 2009 were analyzed. A total of 27 species of medusae were identified (25 hydromedusae and 2 scyphomedusae. Twelve medusae species were recorded for the first time in the Magellan region. Six dominant species were found: Clytia simplex (19.8%, Rhopalonema funerarium (16.2%, Aurelia sp. (15.9%, Bougainvillia muscoides (15.5%, Proboscidactyla stellata (8.9%, and Obelia spp. (6.0%. The horizontal distribution of all these species, except Obelia spp., showed the highest abundances to the south of 54°S, particularly in the Almirantazgo and Agostini fjords and in the Beagle Channel. Most of the dominant species were collected in shallow strata (0-50 m, with less saline waters (<30, except for R. funerarium, which was mainly collected above depths deeper than 25 m in more saline waters (30-33. These results confirm the success of several species in the colonization of the inland waters of the Southern Patagonian Zone.

  7. Structure and function of nematode communities across the Indian western continental margin and its oxygen minimum zone (United States)

    Singh, R.; Ingole, B. S.


    We studied patterns of nematode distribution along the western Indian continental margin to determine the influence of habitat heterogeneity and low oxygen levels on the community's taxonomic and functional structure. A single transect, perpendicular to the coast at 14° N latitude was sampled from 34 to 2546 m depth for biological and environmental variables during August 2007. The oxygen minimum zone extended from 102 to 1001 m. Nematodes (described and undescribed) were identified to species and classified according to biological and functional traits. A total of 110 nematode species belonging to 24 families were found along the transect. Three depth zones were identified: the shelf (depth range: 34-102 m; highest nematode mean density: 176.6 ± 37 ind 10 cm-2), the slope (525-1524 m; 124.3 ± 16 ind 10 cm-2), and the basin (2001-2546 m; 62.9 ± 2 ind 10 cm-2). Across the entire study area, the dominant species were Terschellingia longicaudata, Desmodora sp. 1, Sphaerolaimus gracilis, and Theristus ensifer; their maximum density was at shelf stations. Nematode communities in different zones differed in species composition. Chromadorita sp. 2 (2.78 %) and Sphaerolaimus gracilis (2.21 %) were dominant on the shelf, whereas Terschellingia longicaudata (4.73 %) and Desmodora sp. 1 (4.42 %) were dominant on the slope, but in the basin, Halalaimus sp. 1(1.11 %) and Acantholaimus elegans (1.11 %) were dominant. The information in a particular functional group was not a simple reflection of the information in species abundance. Ecological information captured by adult length, adult shape, and life-history strategy was less site-specific and thus differed notably from information contained in other taxonomic groups. The functional composition of nematodes was strongly linked to the organic-carbon and dissolved-oxygen concentration. Seven species were found exclusively in the oxygen minimum zone: Pselionema sp. 1, Choanolaimus sp. 2, Halichoanolaimus sp. 1, Cobbia dentata

  8. Chronic Brucella Infection Induces Selective and Persistent Interferon Gamma-Dependent Alterations of Marginal Zone Macrophages in the Spleen. (United States)

    Machelart, Arnaud; Khadrawi, Abir; Demars, Aurore; Willemart, Kevin; De Trez, Carl; Letesson, Jean-Jacques; Muraille, Eric


    The spleen is known as an important filter for blood-borne pathogens that are trapped by specialized macrophages in the marginal zone (MZ): the CD209(+) MZ macrophages (MZMs) and the CD169(+) marginal metallophilic macrophages (MMMs). Acute systemic infection strongly impacts MZ populations and the location of T and B lymphocytes. This phenomenon has been linked to reduced chemokine secretion by stromal cells. Brucella spp. are the causative agent of brucellosis, a widespread zoonotic disease. Here, we used Brucella melitensis infection as a model to investigate the impact of chronic stealth infection on splenic MZ macrophage populations. During the late phase of Brucella infection, we observed a loss of both MZMs and MMMs, with a durable disappearance of MZMs, leading to a reduction of the ability of the spleen to take up soluble antigens, beads, and unrelated bacteria. This effect appears to be selective as every other lymphoid and myeloid population analyzed increased during infection, which was also observed following Brucella abortus and Brucella suis infection. Comparison of wild-type and deficient mice suggested that MZ macrophage population loss is dependent on interferon gamma (IFN-γ) receptor but independent of T cells or tumor necrosis factor alpha receptor 1 (TNF-αR1) signaling pathways and is not correlated to an alteration of CCL19, CCL21, and CXCL13 chemokine mRNA expression. Our results suggest that MZ macrophage populations are particularly sensitive to persistent low-level IFN-γ-mediated inflammation and that Brucella infection could reduce the ability of the spleen to perform certain MZM- and MMM-dependent tasks, such as antigen delivery to lymphocytes and control of systemic infection. Copyright © 2017 American Society for Microbiology.

  9. Lateral extension in Sphagnum mires along the southern margin of the boreal region, Western Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Peregon, A; Uchida, M; Yamagata, Y, E-mail: anna.peregon@nies.go.j [Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan)


    Although recent studies have recognized Northern Eurasian ecosystems as an important carbon reservoir, little is known about the forest-peatland interactions in a boreal environment induced by ongoing climatic changes. This study focuses on the evaluation of both the long-term and contemporary trends of land-cover changes and rates of lateral extension of peat-accumulating wetlands toward the adjacent forests, estimated at the southern climatic range of the Sphagnum-dominated mires in Western Siberia. We used the radiocarbon dates and stratigraphy of peat sediments from seven peat cores, analyzed at two types of forest-peatland ecotones, which are located close to each other but differ by topography and composition of their plant communities. The rate of lateral extension was found in a wide range varying from 2.3 to 791.7 cm yr{sup -1}. It was observed to be rapid during the initial stage of mire development, but to have slowed down over the last 2000-3000 yr. Our results, therefore, strongly contradict the concept of progressive peat accumulation throughout the late Holocene and contribute to our knowledge about ongoing land-cover change in the natural ecosystems of the Northern hemisphere.

  10. The majority of cutaneous marginal zone B-cell lymphomas expresses class-switched immunoglobulins and develops in a T-helper type 2 inflammatory environment

    NARCIS (Netherlands)

    van Maldegem, Febe; van Dijk, Remco; Wormhoudt, Thera A. M.; Kluin, Philip M.; Willemze, Rein; Cerroni, Lorenzo; van Noesel, Carel J. M.; Bende, Richard J.


    Extranodal marginal zone B-cell lymphomas (MZBCLs) arise on a background of chronic inflammation resulting from organ-specific autoimmunity, infection, or by unknown causes. Well-known examples are salivary gland MZBCL in Sjorgren's sialadenitis and gastric MZBCL in Helicobacter pylori gastritis.

  11. Farmers' perception on the importance of variegated grasshopper (Zonocerus variegatus (L. in the agricultural production systems of the humid forest zone of Southern Cameroon

    Directory of Open Access Journals (Sweden)

    Messi Jean


    Full Text Available Abstract Background Zonocerus variegatus (Linnaeus, 1758 (Orthoptera: Pyrgomorphidae is known as an agricultural pest in West and Central Africa. However, its importance in the agricultural production system in Cameroon has not been investigated. The study assesses farmers' perception on the importance of Z. variegatus in the agricultural production systems of the humid forest zone of Southern Cameroon. Methods Research was carried out in 5 villages of each of three Agro-Ecological, Cultural and Demographic Blocks (AECD-Blocks of the Forest Margin Benchmark Area (FMBA. In each village, a semi-structured survey was used; male and female groups of farmers were interviewed separately. Results Z. variegatus is present throughout the humid forest zone of Southern Cameroon, where it is ranked as the third most economically important insect pest of agriculture. In the farmers' opinion, Z. variegatus is a polyphagous insect with little impact on young perennial crops. The length of the pre-farming fallow does not affect Z. variegatus pest pressure in the following crops. The increased impact of the grasshopper observed today in the fields, compared to what existed 10 years ago is as a result of deforestation and increase in surface of herbaceous fallow. The damage caused by Z. variegatus is higher in fields adjacent to C. odorata and herbaceous fallows than in those adjacent to forests and shrubby fallows. The fight against this grasshopper is often done through physical methods carried out by hand, for human consumption. The farmers highlight low usage of the chemical methods and a total absence of biological and ecological methods. Conclusion Farmers' perception have contributed to understanding the status of Z. variegatus in the humid forest zone of Southern Cameroon. The results are in general similar to those obtained in other countries.

  12. Benthic-pelagic coupling: effects on nematode communities along southern European continental margins.

    Directory of Open Access Journals (Sweden)

    Ellen Pape

    Full Text Available Along a west-to-east axis spanning the Galicia Bank region (Iberian margin and the Mediterranean basin, a reduction in surface primary productivity and in seafloor flux of particulate organic carbon was mirrored in the in situ organic matter quantity and quality within the underlying deep-sea sediments at different water depths (1200, 1900 and 3000 m. Nematode standing stock (abundance and biomass and genus and trophic composition were investigated to evaluate downward benthic-pelagic coupling. The longitudinal decline in seafloor particulate organic carbon flux was reflected by a reduction in benthic phytopigment concentrations and nematode standing stock. An exception was the station sampled at the Galicia Bank seamount, where despite the maximal particulate organic carbon flux estimate, we observed reduced pigment levels and nematode standing stock. The strong hydrodynamic forcing at this station was believed to be the main cause of the local decoupling between pelagic and benthic processes. Besides a longitudinal cline in nematode standing stock, we noticed a west-to-east gradient in nematode genus and feeding type composition (owing to an increasing importance of predatory/scavenging nematodes with longitude governed by potential proxies for food availability (percentage of nitrogen, organic carbon, and total organic matter. Within-station variability in generic composition was elevated in sediments with lower phytopigment concentrations. Standing stock appeared to be regulated by sedimentation rates and benthic environmental variables, whereas genus composition covaried only with benthic environmental variables. The coupling between deep-sea nematode assemblages and surface water processes evidenced in the present study suggests that it is likely that climate change will affect the composition and function of deep-sea nematodes.

  13. Heavy minerals from the Palos Verdes Margin, Southern California: data and actor analysis (United States)

    Wong, Florence L.


    Heavy or high-density minerals in the 63-250-_m (micron) size fraction (very fine and fine sand) were analyzed from 36 beach and offshore sites (38 samples) of the Palos Verdes margin to determine the areal and temporal mineralogic distributions and the relation of those distributions to the deposit affected by material discharged from the Los Angeles County Sanitation District sewage system (Lee, 1994) (Figure 1). Data presented here were tabulated for a report to the Department of Justice (Wong, 1994). The results of the data analysis are discussed in Wong (in press). The study of heavy minerals is a common method of determining sources (provenance) and distributions of sediments (e.g., Van Andel and Poole, 1960). The choice of grain size is governed by ease of sample preparation, examination by optical microscopy, and comparability to previous studies. How representative the 63-250-_m heavy minerals are of the whole sample can be approximated by the amount of sand in the sample. Lee and others (1994) mapped a pre-effluent, effluent-affected, and surface layer in the study area off Palos Verdes. The amount of sand in the top and pre-effluent layers ranges from about 20 to 80 percent; in the middle of the effluent body, sand is less than 20 percent (Figure 2; MacArthur and others, 1994). Qualitatively, the 63-250-_m heavy minerals are more representative of the top and pre-effluent layer, but these minerals will also provide useful information about the middle layer.

  14. Deep critical zone weathering at the southern Sierra Nevada Critical Zone Observatory imaged by seismic waveform tomography (United States)

    Hayes, J. L.; Holbrook, W.; Riebe, C. S.


    We present seismic velocity profiles that constrain the extent of weathering and frequency of velocity heterogeneities at depths less than 40 m in the southern Sierra Nevada Critical Zone Observatory (SSCZO) from waveform tomography modeling of a seismic refraction experiment. Near-surface variations in seismic velocity reflect differences in alteration of parent material by chemical, hydrological and biological processes. Previous traveltime tomography models from these data suggest that the depth to bedrock in the SSCZO is typically ~25 m; thus the potential for subsurface water storage in regolith may be a larger component of water storage than previously thought. Traveltime tomography is unable to resolve heterogeneities with horizontal wavelengths less than 10 m, such as those observed along a surveyed road cut beneath our seismic profile. For a higher resolution seismic image, we apply waveform tomography, which is more robust than traveltime tomography at approximating the wave equation and thus should provide images of subsurface heterogeneities such as corestones and fracture networks. This technique uses a weak scattering approximation to account for the amplitude and phase of the recorded waveforms, rather than just the traveltimes. A 48-channel vertical geophone array and hammer source was deployed over a 7 m high road cut with receiver and shot spacing of 2 m and 4 m respectively. The road cut displays lateral variation in weathering from a friable saprolite to coherent granodiorite which are compared to velocity variations modeled using waveform tomography.

  15. Finite deformation and displacement fields on the southern yemen margin using satellite images, topographic data and a restoration method (United States)

    Thoue, Frédéric; Vidal, Gérard; Gratier, Jean-Pierre


    Geological interpretations of processed satellite images and structural field measurements were used to calculate the amount of extension and the finite displacement field of two stretched areas located on the northern margin of the Gulf of Aden, in Yemen. This calculation was done by a comparison between the deformed and the undeformed states of each studied area. The structural setting established from satellite-image interpretations and fieldwork yields a detailed geometry of the deformed state. The undeformed state was reconstructed from reference layers chosen on satellite images from folded and faulted geological markers. The strike and dip of those layers were computed directly from dip indicator measurements, identified on three-dimensional (3D) realistic views of the sites (derived from SPOT stereoscopic views and topographic data) and controlled by field measurements. From the previous structural data, a numerical model of the deformed state was prepared with respect to the structural setting. The two stretched areas were then restored to their undeformed state successively by (1) an unfolding method (use of the UNFOLD program on each folded piece bounded by faults), and (2) a best-fit method (fitting along the boundary of the unfolded pieces). The comparison between the deformed and undeformed states leads to quantifying the amount of strain and to establishing the total finite displacement field. The results point to differences in the amount of extension and in the finite displacement field between the two areas studied. Within the regional context of the Afar triple junction kinematics, this leads to the conclusion that there was an early extensional tectonic phase recorded on the southern Yemen margin, probably linked to the earlier opening of the Gulf of Aden.

  16. Cenozoic Extension of the Southern Menderes Massif along the Kayabuku Shear Zone, Western Anatolia Extended Terrane, Turkey (United States)

    Diniz, E.; Cemen, I.; Catlos, E. J.; Konak, N.; Goncuoglu, C. M.; Kohn, M. J.; Baker, C.; Hancer, M.


    Four major low angle extensional shear zones are located in the Menderes massif of the Western Anatolia Extended Terrane in western Turkey. The shear zones are, from north to south, Simav, Alasehir, Buyuk Menderes and Kayabuku (Selimiye) shear zones. We have conducted a detailed field oriented study to determine the role of the Kayabuku (Selimiye) shear zone in the Cenozoic extensional evolution of the Menderes massif. The south-dipping Kayabuku (Selimiye) shear zone of the southern Menderes massif contains well- developed mesoscopic and microscopic shear sense indicators, and separates orthogneiss and augengneiss in its footwall from schist and marble rock units in its hanging wall. Within the shear zone, the average attitude of the foliation planes between the towns of Milas and Yatagan is measured as N86W/50°S. The shear zone shows two ductile sense of shearing; 1) top to the north and 2) top to the south which overprinted the former one. Many thin sections also show top to the south brittle shear sense indicators overprinting the ductile shear sense indicators. The trend of the ductile shear sense indicators, such as stretching lineations, range from N10E to N30E indicating that they are parallel to the shear sense indicators measured along the Simav shear zone of the northern and, Alasehir and Buyuk Menderes shear zones of the central Menderes massif. This suggests to us that the Cenozoic extension which was initiated in Oligocene by the processes of Orogenic Collapse effected the Kayabuku (Selimiye) shear zone. The hanging wall of the Kayabuku shear zone is also locally brittely deformed by a south-dipping normal fault zone, discontinuously exposed between the schist and marble units. The fault zone suggests that the hanging wall of the shear zone has been brittely deformed during the extensional exhumation of the southern Menderes massif. Our field observations and microtectonic studies suggest that the rocks within the Kayabuku (Selimiye) shear zone gained

  17. The evolution of the southern margin of the East European Craton based on seismic and potential field data (United States)

    Kostyuchenko, S. L.; Morozov, A. F.; Stephenson, R. A.; Solodilov, L. N.; Vedrentsev, A. G.; Popolitov, K. E.; Aleshina, A. F.; Vishnevskaya, V. S.; Yegorova, T. P.


    This paper presents an integrated geophysical study of the southern margin of the East European Craton (EEC) in the Karpinksy Swell-North Caucasus area. It presents new interpretations of deep refraction and wide-angle reflection "deep seismic sounding" (DSS) data as well as conventional seismic and CDP profiling and new analyses of potential field data, including three-dimensional gravity and magnetic modelling. An integrated model of the physical properties and structure of the Earth's crust and, partially, upper mantle displays distinct features that are related to tectonic history of the study area. The Voronezh Massif (VM), the Ukrainian Shield and Rostov Dome (RD) of the EEC as well as the Donbas Foldbelt (DF), Karpinsky Swell (KS), Scythian Plate (SP) and Precaspian Basin (PCB) constitute the geodynamic ensemble that developed on the southern margin of the continent Baltica. There proposed evolutionary model comprises a stage of rifting during the middle to late Devonian, post-rift extension and subsidence during Carboniferous-early Permian times (synchronous with and related to the southward displacement of the Rostov Dome and extension in a palaeo-Scythian back-arc basin), and subsequent Mesozoic and younger evolution. A pre-Ordovician, possibly Riphean (?), mafic magmatic complex is inferred on a near vertical reflection seismic cross-section through the western portion of the Astrakhan Dome in the southwest part of the Precaspian Basin. This complex combined with evidence of a subducting slab in the upper mantle imply the presence of pre-Ordovician (Riphean?) island arc, with synchronous extension in a Precaspian back-arc basin is suggested. A middle Palaeozoic back-arc basin ensemble in what is now the western Karpinsky Swell was more than 100 km to the south from its present location. The Stavropol High migrated northwards, dislocating and moving fragments of this back-arc basin sometime thereafter. Linear positive magnetic anomalies reflect the

  18. Variability of the fauna within drifting sea ice floes in the seasonal ice zone of the Southern Ocean during the austral summer (United States)

    Ojima, Motoha; Takahashi, Kunio T.; Iida, Takahiro; Moteki, Masato; Miyazaki, Naho; Tanimura, Atsushi; Odate, Tsuneo


    Sea ice covering the seasonal ice zone in the Southern Ocean contains micro-organisms (sea ice biota). Studies of sea ice biota have mostly been conducted on the land-fast ice and large ice floes, despite most sea ice in the Southern Ocean being seasonal and drifting ice types. We sampled 17 drifting sea ice floes in the marginal ice zone off Adélie Land, East Antarctica, in January 2013 and 2014. We found high densities of copepods such as Harpacticoida species (18,787 ± 50,647 inds.m-3), Paralabidocera antarctica (1773 ± 6370) and their nauplii (69,943 ± 149,607), as well as foraminiferans (193,869 ± 408,721) within ice. Variability in the animal assemblages among the different ice floes was observed. Cluster analysis of samples based on the assemblage of sea ice fauna revealed two major groups, which were divided by the year of the sampling, and were dominated by harpacticoid nauplii and foraminiferans, respectively. Sea ice trajectory and drifting duration estimated from satellite data were different for both years, although the origin of the sea ice was in the same bay. This study suggests that the variability of fauna among sea ice floes may reflect the continuance period of ice formation and the trajectory from where they originated.

  19. Late Paleozoic accretionary complexes on the Gondwana margin of southern Chile: Evidence from the Chonos Archipelago (United States)

    Davidson, John; Mpodozis, Constantino; Godoy, Estanislao; Hervé, Francisco; Pankhurst, Robert; Brook, Maureen

    The late Paleozoic "basement" rocks that crop out along the Pacific side of the Chonos Archipelago (44°-46°S) can be divided into two north-south trending belts: (1) an eastern belt formed of submarine fan-turbidites and subordinate pelagic cherts, each containing well-preserved primary sedimentary structures, and (2) a western belt, mainly formed by strongly foliated mica schists and greenschists. Trace element contents in the cherts and greenschists indicate rocks of oceanic affinity. The structures present within the eastern rock suite are principally subiso-clinal folds (with tectonic imbrication) and locally developed zones of broken formation. The transition from these rocks into the foliated schists appears to be related to a progressive increase in metamorphism and strain associated with the development of westward verging recumbent folds and a flat-lying crenulation cleavage. It is inferred that these structures developed during the construction of a Late Carboniferous-Early Permian accretionary prism (about 260 Ma Rb-Sr ages), although sedimentation may have taken place throughout the upper Paleozoic. Rb-Sr whole-rock isochrons giving Late Jurassic to Early Cretaceous ages for some localities may indicate much later development of S2 structures. Alternatively, they may represent isotopic resetting by hydrothermal effects during the emplacement of transgressive Early Cretaceous granites, one of which gives a new Rb-Sr isochron age of 125±2Ma. This overall scenario seems to be consistent with that reported in the slightly older coastal metamorphic basement north of 34°S and equivalent or younger complexes farther south in the Madre de Dios Archipelago.

  20. Mid-Late Mississippian Paleoceanography at the Southern Margin of Laurasia (United States)

    Hoelke, J.; Rowe, H. D.


    The Mississippian (Visean-Serpukhovian) Barnett Formation is a lithologic unit composed primarily of laminated siliceous mudrock with some lime mudrock intervals. The Barnett Formation was deposited in the Fort Worth Basin, a marine foreland basin that formed as a result of the early Ouachita Orogeny from the collision of Laurasia and Gondwana. The focus of the research project will better characterize the different aspects of the Barnett Formation paleodepositional environment in the southern Fort Worth Basin including: degree of basin restriction, redox conditions, organic character, and other geochemical changes along a northeast-southwest transect of the basin. This will be accomplished by examining the Barnett Formation chemostratigraphy and linking it with observed sedimentological changes in Barnett strata. Eight drill cores from four counties in Central Texas will be evaluated. Each core was scanned at a 1-foot (~0.3m) interval with an X-ray fluorescence (XRF) spectrometer to provide quantitative analysis of the following elemental concentrations: Mg, Al, S, Si, P, K, Ti, Ca, Mn, Fe, Mo, Cr, Co, Ni, Cu, Zn, Th, Rb, U, Sr, Zr, and V. In addition, total organic carbon (TOC), total inorganic carbon (TIC), percent nitrogen and sulfur data will be gathered from each core. At present, major and trace element XRF data are available from six cores. In addition, TOC, TIC, nitrogen and sulphur data is available for three cores. Preliminary data show that the Barnett Formation from the cores is largely siliceous mudstone. It is unclear whether the silica is of a biogenic or detrital origin. Elevated concentrations of redox-sensitive trace elements, including molybdenum, vanadium, zinc and uranium indicate that periods of anoxia and euxinia existed during deposition. These conditions likely contributed to a high level of preservation for organic material. Total organic carbon (TOC) averages 4.3% for the three cores for which data are available. Initial analysis of the

  1. Transformation and additional malignancies are leading risk factors for an adverse course of disease in marginal zone lymphoma. (United States)

    Meyer, A H; Stroux, A; Lerch, K; Eucker, J; Eitle, J; Hohloch, K; Andrzejak, M; Possinger, K; Dörken, B; Pezzutto, A; Scholz, C W


    Marginal zone lymphoma (MZL) is a non-Hodgkin lymphoma that occurs as extra nodal, nodal, or splenic. While MZL is generally considered an indolent disease, a substantial percentage of patients follow an unfavorable course. The objective of this retrospective analysis was to identify predictors for a reduced overall survival (OS), or conversely an increased OS. One hundred and ninety-seven MZL patients were analyzed. Apart from assessing previously published risk factors, concomitant morbidity at diagnosis, transformation into aggressive lymphoma, and occurrence of additional malignancies were evaluated. Next to the known risk factors, i.e. above 60 years of age and elevated serum lactate dehydrogenase (LDH), we demonstrate that transformation into aggressive lymphoma, as well as additional malignancies, are important independent risk factors for a shortened OS in a multivariate analysis, irrespective of the MZL localization. Impressively, in the group of patients lacking LDH elevation, transformation, and/or additional malignancies, only 1 of 63 patients died during follow-up compared with 37 of 87 patients in the high-risk group (HR = 22.8; 95% confidence interval 3.1-167.0; P = 0.002). Our analysis proposes novel risk factors and warrants for a continuous follow-up to detect the occurrence of transformation and additional malignancies early on.

  2. Expression of Immunoglobulin Receptors with Distinctive Features Indicating Antigen Selection by Marginal Zone B Cells from Human Spleen (United States)

    Colombo, Monica; Cutrona, Giovanna; Reverberi, Daniele; Bruno, Silvia; Ghiotto, Fabio; Tenca, Claudya; Stamatopoulos, Kostas; Hadzidimitriou, Anastasia; Ceccarelli, Jenny; Salvi, Sandra; Boccardo, Simona; Calevo, Maria Grazia; De Santanna, Amleto; Truini, Mauro; Fais, Franco; Ferrarini, Manlio


    Marginal zone (MZ) B cells, identified as surface (s)IgMhighsIgDlowCD23low/−CD21+CD38− B cells, were purified from human spleens, and the features of their V(D)J gene rearrangements were investigated and compared with those of germinal center (GC), follicular mantle (FM) and switched memory (SM) B cells. Most MZ B cells were CD27+ and exhibited somatic hypermutations (SHM), although to a lower extent than SM B cells. Moreover, among MZ B-cell rearrangements, recurrent sequences were observed, some of which displayed intraclonal diversification. The same diversifying sequences were detected in very low numbers in GC and FM B cells and only when a highly sensitive, gene-specific polymerase chain reaction was used. This result indicates that MZ B cells could expand and diversify in situ and also suggested the presence of a number of activation-induced cytidine deaminase (AID)-expressing B cells in the MZ. The notion of antigen-driven expansion/selection in situ is further supported by the VH CDR3 features of MZ B cells with highly conserved amino acids at specific positions and by the finding of shared (“stereotyped”) sequences in two different spleens. Collectively, the data are consistent with the notion that MZ B cells are a special subset selected by in situ antigenic stimuli. PMID:23877718

  3. Chemical characterization of fractions of dissolved humic substances from a marginal sea—a case from the Southern Yellow Sea (United States)

    Zhang, Yaoling; Yang, Keli; Du, Jinzhou; Zhang, Fenfen; Dong, Yaping; Li, Wu


    Marine dissolved organic matter (DOM) is one of the largest dynamic pools of organic carbon in the global carbon cycle, yet DOM is still chemically poorly characterized. To better understand the origin, composition, and cycling of DOM in the China marginal sea, dissolved humic substances (DHS) were isolated from seawaters in two locations in the Southern Yellow Sea. The DHS were subdivided into fulvic acids (FAs), humic acids (HAs) and the XAD-4 fractions. Complementary analytical approaches were used to characterize the isolated DHS samples including stable carbon isotopic composition, Fourier transform infrared spectroscopy (FTIR), 13C cross polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR), and pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The results demonstrated that both DHS samples encountered the influences from marine source, indicating that algal and microbial-derived materials are the predominant precursors for the studied samples. The three fractions of DHS showed different properties. FAs presented more aromatic features, whereas HAs contained more aliphatic lipids and proteinaceous materials. The XAD-4 fractions were enriched in 13C and contained more carbohydrates but less aromatic compounds. The lower molecular weight and higher heteroatom content and number of carboxyl groups for the XAD-4 fractions may give them considerable geochemical significance for aspects of trace metal species, bioavailability of pollutants, mineral weathering and water acidification in marine environments.

  4. A hybrid zone of the genus Ctenomys: a case study in southern Brazil

    Directory of Open Access Journals (Sweden)

    Camila S. Castilho


    Full Text Available We describe variation at microsatellite loci and the chromosomal polymorphisms of a hybrid population, and hybridizing populations of Ctenomys minutus (the minor tuco-tuco from the coastal plain of Rio Grande do Sul, southern Brazil. Cytogenetic analysis and a survey of six microsatellite loci included 101 specimens of C. minutus from the parental populations (2n/AN = 42/74 and 48a/76 and their contact zone. Cytogenetic analysis recorded 26 different karyotypes exhibited by 50 individuals from the hybrid population. Of the 26 karyotypes, only 14% presented a parental-like configuration, and none had the combinations of 2n and AN expected for an F1 hybrid. The remaining karyotypes were alternative hybrid forms, with 2n varying from 42 to 46 and AN from 68 to 80. These results suggest chromosomal rearrangements are only of minor significance in the establishment of reproductive barriers for this species.

  5. Marginal Ice Zone Bibliography. (United States)


    on sea ice area.) Akademiia Nauk SSSR. Tikho- okeanskii Institut Geografii. Issledovanie Sistemy ’Lednikii-Okean- Atmosfera ’. Vladivostok, p.23-28. 66...Sistemy ’Lednikii-Okean- Atmosfera ’. Vladivostok, p.23-28. Keen, R.A., 1977: The response of Baffin Bay ice conditions to changes in atmospheric...surface atmosphere on sea ice area.) Akademiia Nauk SSSR. Tikho- okeanskii Institut Geografii. Issledovanie Sistemy ’Lednikii-Okean- Atmosfera

  6. Influence of tropical easterlies in southern Africa's winter rainfall zone during the Holocene (United States)

    Chase, Brian M.; Lim, Sophak; Chevalier, Manuel; Boom, Arnoud; Carr, Andrew S.; Meadows, Michael E.; Reimer, Paula J.


    South Africa's southwestern Cape occupies a critical transition zone between Southern Hemisphere temperate (winter) and tropical (summer) moisture-bearing systems. In the recent geological past, it has been proposed that the relative influence of these systems may have changed substantially, but little reliable evidence regarding regional hydroclimates and rainfall seasonality exists to refine or substantiate the understanding of long-term dynamics. In this paper we present a mid-to late Holocene multi-proxy record of environmental change from a rock hyrax midden from Katbakkies Pass, located along the modern boundary between the winter and summer rainfall zones. Derived from stable carbon and nitrogen isotopes, fossil pollen and microcharcoal, these data provide a high resolution record of changes in humidity, and insight into changes in rainfall seasonality. Whereas previous work concluded that the site had generally experienced only subtle environmental change during the Holocene, our records indicate that significant, abrupt changes have occurred in the region over the last 7000 years. Contrary to expectations based on the site's location, these data indicate that the primary determinant of changes in humidity is summer rather than winter rainfall variability, and its influence on drought season intensity and/or length. These findings are consistent with independent records of upwelling along the southern and western coasts, which indicate that periods of increased humidity are related to increased tropical easterly flow. This substantially refines our understanding of the nature of temperate and tropical circulation system dynamics in SW Africa, and how changes in their relative dominance have impacted regional environments during the Holocene.

  7. Mid-Neoproterozoic intraplate magmatism in the northern margin of the Southern Granulite Terrane, India: Constraints from geochemistry, zircon U-Pb geochronology and Lu-Hf isotopes (United States)

    Deeju, T. R.; Santosh, M.; Yang, Qiong-Yan; Pradeepkumar, A. P.; Shaji, E.


    The northern margin of the Southern Granulite Terrane in India hosts a number of mafic, felsic and alkaline magmatic suites proximal to major shear/paleo-suture zones and mostly represents magmatism in rift-settings. Here we investigate a suite of gabbros and granite together with intermediate (dioritic) units generated through mixing and mingling of a bimodal magmatic suite. The massive gabbro exposures represent the cumulate fraction of a basic magma whereas the granitoids represent the product of crystallization in felsic magma chambers generated through crustal melting. Diorites and dioritic gabbros mostly occur as enclaves and lenses within host granitoids resembling mafic magmatic enclaves. Geochemistry of the felsic units shows volcanic arc granite and syn-collisional granite affinity. The gabbro samples show mixed E-MORB signature and the magma might have been generated in a rift setting. The trace and REE features of the rocks show variable features of subduction zone enrichment, crustal contamination and within plate enrichment, typical of intraplate magmatism involving the melting of source components derived from both depleted mantle sources and crustal components derived from older subduction events. The zircons in all the rock types show magmatic crystallization features and high Th/U values. Their U-Pb data are concordant with no major Pb loss. The gabbroic suite yields 206Pb/238U weighted mean ages in the range of 715 ± 4-832.5 ± 5 Ma marking a major phase of mid Neoproterozoic magmatism. The diorites crystallized during 206Pb/238U weighted mean age of 724 ± 6-830 ± 2 Ma. Zircons in the granite yield 206Pb/238U weighted mean age of 823 ± 4 Ma. The age data show broadly similar age ranges for the mafic, intermediate and felsic rocks and indicate a major phase of bi-modal magmatism during mid Neoproterozoic. The zircons studied show both positive and negative εHf(t) values for the gabbros (-6.4 to 12.4), and negative values for the diorites (-7

  8. Quantifying the Floe Size Distribution in the Marginal Ice Zone from Satellite Imagery for use in Model Development and Validation (United States)

    Schweiger, A. J.; Stern, H. L.; Stark, M.; Zhang, J.; Hwang, P.; Steele, M.


    Several key processes in the Marginal Ice Zone (MIZ) of the Arctic Ocean are related to the size of the ice floes, whose diameters range from meters to tens of kilometers. The floe size distribution (FSD) influences mechanical properties of the ice and thus its response to winds, currents, and waves, which is likely to modify the air-sea momentum transfer. The FSD also influences the air-sea heat transfer and the response of the MIZ ice cover to the thermal forcing. The FSD also has a significant role in lateral melting. No existing sea-ice/ocean models currently simulate the FSD in the MIZ. Significant uncertainties in FSD-related processes hinder model incorporation of the FSD, and model development must heavily depend on observations of the FSD for parameterization, calibration, and validation. To support the development and implementation of the FSD in the Marginal Ice Zone Modeling and Assimilation System (MIZMAS), we have conducted an analysis of the FSD in the Beaufort and Chukchi seas using three sources of satellite imagery: NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua satellites, the Canadian Space Agency's synthetic aperture radar (SAR) on RADARSAT, and declassified National Technical Means imagery from the Global Fiducials Library (GFL) of the U.S. Geological Survey. The MODIS visible and short-wave infrared bands have a pixel size of 250 meters, and are only useful in cloud-free regions. The SAR imagery is unaffected by clouds and darkness, and has a pixel size of 50 meters. The GFL visible imagery, with a pixel size of 1 meter, is only useful in cloud-free regions. The resolution and spatial extent of the various image products allows us to identify ice floes of all sizes from 10 meters to 100 kilometers. The general procedure for identifying ice floes in the imagery is as follows: delineate cloud-free regions (if necessary); choose a threshold to separate ice from water, and create a binary image; apply the

  9. Induced abortion and associated factors in health facilities of Guraghe zone, southern Ethiopia. (United States)

    Tesfaye, Gezahegn; Hambisa, Mitiku Teshome; Semahegn, Agumasie


    Unsafe abortion is one of the major medical and public health problems in developing countries including Ethiopia. However, there is a lack of up-to-date and reliable information on induced abortion distribution and its determinant factors in the country. This study was intended to assess induced abortion and associated factors in health facilities of Guraghe zone, Southern Ethiopia. Institution based cross-sectional study was conducted in eight health facilities in Guraghe zone. Client exit interview was conducted on 400 patients using a structured questionnaire. Bivariate and multivariate logistic regression analysis was performed to identify factors associated with induced abortion. Out of 400 women, 75.5% responded that the current pregnancy that ended in abortion is unwanted. However, only 12.3% of the respondents have admitted interference to the current pregnancy. Having more than four pregnancies (AOR = 4.28, CI: (1.24-14.71)), age of 30-34 years (AOR = 0.15, CI: (0.04-0.55)), primary education (AOR = 0.26, CI: (0.13-0.88)), and wanted pregnancy (AOR = 0.44, CI: (0.14-0.65)) were found to have association with induced abortion. The study revealed high level of induced abortion which is underpinned by high magnitude of unwanted pregnancy. There is requirement for widespread expansion of increased access to high quality family planning service and post-abortion care.

  10. Mercury concentration variability in the zooplankton of the southern Baltic coastal zone (United States)

    Bełdowska, Magdalena; Mudrak-Cegiołka, Stella


    Being a toxic element, mercury is introduced to the human organism through the consumption of fish and seafood, which in turn often feed on zooplankton. The bioaccumulation of Hg by zooplankton is an important factor influencing the magnitude of the mercury load introduced with food into the predator organism. Therefore the present article attempts to identify the processes and factors influencing Hg concentration in the zooplankton of the coastal zone, an area where marine organisms - an attractive food source for humans - thrive. This is particularly important in areas where climate changes influence the species composition and quantity of plankton. The studies were carried out on three test sites in the coastal zone of the southern Baltic Sea in the period from December 2011 to May 2013. The obtained results show that the shorting of the winter season is conducive to Hg increase in zooplankton and, consequently, in the trophic chain. High mercury concentrations were measured in genus Synchaeta and Keratella when Mesodinium rubrum were predominant in phytoplankton, while other sources of this metal in the plankton fauna were epilithon, epiphton and microbenthos. This is of particular importance when it comes to sheltered bays and estuaries with low water dynamics.

  11. Permissible emission limit estimation via iterative back-calculation: Case of Assaluyeh energy zone, southern Iran. (United States)

    Khajehpour, Hossein; Saboohi, Yadollah; Tsatsaronis, George


    In the present research work, an environmental policy procedure for setting a cap on emissions, as a crucial step in any total emission control system, has been provided and evaluated. It is shown that general regulations on emission intensities and rates do not guarantee that ambient air quality standards are met in intense industrial zones. Local emission limits are necessary to meet ambient air quality standards in these zones. To that end, we used dispersion simulators to back-calculate pollutant concentration thresholds for a large and intense energy system in the Assaluyeh region of southern Iran. Verified modeling results indicate 218 d of pollutant concentration threshold exceedance in Assaluyeh in a simulated year. Back-calculation to assess the total permissible emission level indicates the need for 68% reduction in total emission to meet ambient air quality standards. We then used the model to help identify effective control strategies, including emission reductions and appropriate timing of specific operations. Integr Environ Assess Manag 2018;14:130-138. © 2017 SETAC. © 2017 SETAC.

  12. Selective preservation of bone marrow mature recirculating but not marginal zone B cells in murine models of chronic inflammation.

    Directory of Open Access Journals (Sweden)

    Elisabetta Traggiai

    Full Text Available Inflammation promotes granulopoiesis over B lymphopoiesis in the bone marrow (BM. We studied B cell homeostasis in two murine models of T cell mediated chronic inflammation, namely calreticulin-deficient fetal liver chimeras (FLC, which develop severe blepharitis and alopecia due to T cell hyper responsiveness, and inflammatory bowel disease (IBD caused by injection of CD4(+ naïve T cells into lymphopenic mice. We show herein that despite the severe depletion of B cell progenitors during chronic, peripheral T cell-mediated inflammation, the population of BM mature recirculating B cells is unaffected. These B cells are poised to differentiate to plasma cells in response to blood borne pathogens, in an analogous fashion to non-recirculating marginal zone (MZ B cells in the spleen. MZ B cells nevertheless differentiate more efficiently to plasma cells upon polyclonal stimulation by Toll-like receptor (TLR ligands, and are depleted during chronic T cell mediated inflammation in vivo. The preservation of mature B cells in the BM is associated with increased concentration of macrophage migration inhibitory factor (MIF in serum and BM plasma. MIF produced by perivascular dendritic cells (DC in the BM provides a crucial survival signal for recirculating B cells, and mice treated with a MIF inhibitor during inflammation showed significantly reduced mature B cells in the BM. These data indicate that MIF secretion by perivascular DC may promote the survival of the recirculating B cell pool to ensure responsiveness to blood borne microbes despite loss of the MZ B cell pool that accompanies depressed lymphopoiesis during inflammation.

  13. gp49B-mediated negative regulation of antibody production by memory and marginal zone B cells. (United States)

    Fukao, Saori; Haniuda, Kei; Nojima, Takuya; Takai, Toshiyuki; Kitamura, Daisuke


    The rapid Ab responses observed after primary and secondary immunizations are mainly derived from marginal zone (MZ) and memory B cells, respectively, but it is largely unknown how these responses are negatively regulated. Several inhibitory receptors have been identified and their roles have been studied, but mainly on follicular B cells and much less so on MZ B, and never on memory B cells. gp49B is an Ig superfamily member that contains two ITIMs in its cytoplasmic tail, and it has been shown to negatively regulate mast cell, macrophage, and NK cell responses. In this study, we demonstrate that gp49B is preferentially expressed on memory and MZ B cells. We show that gp49B(-/-) mice produce more IgM after a primary immunization and more IgM and IgG1 after a secondary immunization than gp49B(+/+) mice in T cell-dependent immune responses. Memory and MZ B cells from gp49B(-/-) mice also produce more Abs upon in vitro stimulation with CD40 than those from gp49B(+/+) mice. The in vitro IgM production by MZ B cells from gp49B(+/+), but not gp49B(-/-), mice is suppressed by interaction with a putative gp49B ligand, the integrin αvβ3 heterodimer. In addition, gp49B(-/-) mice exhibited exaggerated IgE production in the memory recall response. These results suggest that plasma cell development from memory and MZ B cells, as well as subsequent Ab production, are suppressed via gp49B. In memory B cells, this suppression also prevents excessive IgE production, thus curtailing allergic diseases. Copyright © 2014 by The American Association of Immunologists, Inc.

  14. Robust wavebuoys for the marginal ice zone: Experiences from a large persistent array in the Beaufort Sea

    Directory of Open Access Journals (Sweden)

    Martin J. Doble


    Full Text Available An array of novel directional wavebuoys was designed and deployed into the Beaufort Sea ice cover in March 2014, as part of the Office of Naval Research 'Marginal Ice Zone' experiment. The buoys were designed to drift with the ice throughout the year and monitor the expected breakup and retreat of the ice cover, forced by waves travelling into the ice from open water. Buoys were deployed from fast-and-light air-supported ice camps, based out of Sachs Harbour on Canada’s Banks Island, and drifted westwards with the sea ice over the course of spring, summer and autumn, as the ice melted, broke up and finally re-froze. The buoys transmitted heave, roll and pitch timeseries at 1 Hz sample frequency over the course of up to eight months, surviving both convergent ice dynamics and significant waves-in-ice events. Twelve of the 19 buoys survived until their batteries were finally exhausted during freeze-up in late October/November. Ice impact was found to have contaminated a significant proportion of the Kalman-filter-derived heave records, and these bad records were removed with reference to raw x/y/z accelerations. The quality of magnetometer-derived buoy headings at the very high magnetic field inclinations close to the magnetic pole was found to be generally acceptable, except in the case of four buoys which had probably suffered rough handling during transport to the ice. In general, these new buoys performed as expected, though vigilance as to the veracity of the output is required.

  15. Activity-dependent endogenous taurine release facilitates excitatory neurotransmission in the neocortical marginal zone of neonatal rats

    Directory of Open Access Journals (Sweden)

    Taizhe eQian


    Full Text Available In the developing cerebral cortex, the marginal zone (MZ, consisting of early-generated neurons such as Cajal-Retzius cells, plays an important role in cell migration and lamination. There is accumulating evidence of widespread excitatory neurotransmission mediated by γ-aminobutyric acid (GABA in the MZ. Cajal-Retzius cells express not only GABAA receptors but also α2/β subunits of glycine receptors, and exhibit glycine receptor-mediated depolarization due to high [Cl−]i. However, the physiological roles of glycine receptors and their endogenous agonists during neurotransmission in the MZ are yet to be elucidated. To address this question, we performed optical imaging from the MZ using the voltage-sensitive dye JPW1114 on tangential neocortical slices of neonatal rats. A single electrical stimulus evoked an action-potential-dependent optical signal that spread radially over the MZ. The amplitude of the signal was not affected by glutamate receptor blockers, but was suppressed by either GABAA or glycine receptor antagonists. Combined application of both antagonists nearly abolished the signal. Inhibition of Na+, K+-2Cl− cotransporter by 20 µM bumetanide reduced the signal, indicating that this transporter contributes to excitation. Analysis of the interstitial fluid obtained by microdialysis from tangential neocortical slices with high-performance liquid chromatography revealed that GABA and taurine, but not glycine or glutamate, were released in the MZ in response to the electrical stimulation. The ambient release of taurine was reduced by the addition of a voltage-sensitive Na+ channel blocker. Immunohistochemistry and immunoelectron microscopy indicated that taurine was stored both in Cajal-Retzius and non-Cajal-Retzius cells in the MZ, but was not localized in presynaptic structures. Our results suggest that activity-dependent non-synaptic release of endogenous taurine facilitates excitatory neurotransmission through activation of

  16. Small-scale sea ice deformation during N-ICE2015: From compact pack ice to marginal ice zone (United States)

    Oikkonen, Annu; Haapala, Jari; Lensu, Mikko; Karvonen, Juha; Itkin, Polona


    We studied small-scale (50 m to 5 km) sea ice deformation from ship radar images recorded during the N-ICE2015 campaign. The campaign consisted of four consecutive drifting ice stations (Floes 1-4) north of Svalbard, with a total duration of nearly 5 months. Deformation was calculated using 5 different time intervals from 10 min to 24 h, and the deformation rate was found to depend strongly on the time scale. Floes 1-3 had a mean deformation rate within the range of 0.06-0.07 h-1 with the interval of 10 min, and 0.03-0.04 h-1 with the interval of 1 h. Floe 4 represented marginal ice zone (MIZ) with very high deformation rate, 0.14/0.08 h-1 with the interval of 10 min/1 h. Deep in the ice pack, high deformation rates occurred only with high wind and drift speed, while in MIZ they were found also during calm conditions. The deformation rates were found to follow power law scaling with respect to length and time scale even on this small scale and in small domain (15 km × 15 km). The length scale dependence of deformation rate depends on the time scale: the power law scaling exponent β of the whole study period decreases from 0.82 to 0.52 with the time interval increasing from 10 min to 24 h. Ship radar images reveal the importance of the deformation history of the ice pack, since the deformation events were initialized along the lines of previous damages.

  17. Persistent indolent pancolonic marginal zone lymphoma of MALT-type with plasmacytic differentiation – A rare post-transplant lymphoma?

    Directory of Open Access Journals (Sweden)

    Joanna M. Chaffin


    Full Text Available Marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma is associated with chronic inflammatory disorders. We present an indolent pancolonic MALT lymphoma occurring in a 39-year-old female with history of autoimmune hepatitis requiring liver transplant in 1997 and ulcerative colitis diagnosed in 2004. Random biopsies from a grossly unremarkable surveillance colonoscopy in 2015 revealed a dense monomorphic plasmacytoid infiltrate causing expansion of lamina propria without significant crypt infiltration or destruction. These cells were positive for CD79a and CD138 and showed lambda restriction; however, CD20, CD43, CD56, HHV8, and EBER were negative. A similar pancolonic infiltrate was identified in all prior colorectal biopsies from 2010 and 2012 upon retrospective review. Subsequent computed tomography of the abdomen revealed no bowel wall thickening nor enlarged lymph nodes. Bone marrow revealed involvement consistent with stage IV disease. Biopsies from 2010 and 2015 demonstrated clonal immunoglobulin gene rearrangement. MYD88 mutation was not detected. The overall features were indicative of MALT lymphoma. Although low-grade B-cell lymphomas are not considered part of the post-transplant lymphoproliferative disorder spectrum, such cases have been reported, and are typically EBV-negative. Patient underwent treatment with pentostatin for her MALT lymphoma reaching a sustained remission despite additional immunosuppression for resurgent hepatic dysfunction. To our knowledge, this is the first reported case of EBV-negative pancolonic MALT lymphoma with plasmacytic differentiation post liver transplant presenting in an indolent, asymptomatic fashion with persistence for greater than five years successfully managed without compromising the patient's liver transplant.

  18. Impact of the invasive species Elaeagnus Angustifolia L. on vegetation in Pontic desert steppe zone (Southern Ukraine)

    NARCIS (Netherlands)

    Sudnik-Wojcikowska, B.; Moysiyenko, I.; Slim, P.A.; Moraczewski, I.R.


    The Irano-Turanian species – Russian olive (Elaeagnus angustifolia L.) – is one of most commonly planted tree in the shelterbelts in southern Ukraine. The consequences of introduction of the species from windbreaks, into areas of different land use in west and central Pontic desert steppe zone are

  19. Teachers of Poor Communities: The Tale of Instructional Media Use in Primary Schools of "Gedeo" Zone, Southern Ethiopia (United States)

    Abdo, Mehadi; Semela, Tesfaye


    The purpose of this study was to investigate the impact of working conditions at school on teachers' level of instructional media use in the primary school system of Gedeo Zone, southern Ethiopia. The survey was made on a sample of 139 (24.4% female and male 75.6%) teachers who were randomly drawn from 9 primary schools (four rural and five urban…

  20. The Relationship between Teachers Commitment and Female Students Academic Achievements in Some Selected Secondary School in Wolaita Zone, Southern Ethiopia (United States)

    Bibiso, Abyot; Olango, Menna; Bibiso, Mesfin


    The purpose of this study was to investigate the relationship between teacher's commitment and female students academic achievement in selected secondary school of Wolaita zone, Southern Ethiopia. The research method employed was survey study and the sampling techniques were purposive, simple random and stratified random sampling. Questionnaire…

  1. Soil macrofauna community structure along a gradient of land use intensification in the humid forest zone of southern Cameroon.

    NARCIS (Netherlands)

    Madong à Birang,


    The impact of land use systems on soil macrofauna community structures is described as well as their relationships with the vegetation and soil parameters in the humid forest zone of southernCameroon

  2. Pre-existing oblique transfer zones and transfer/transform relationships in continental margins: New insights from the southeastern Gulf of Aden, Socotra Island, Yemen (United States)

    Bellahsen, N.; Leroy, S.; Autin, J.; Razin, P.; d'Acremont, E.; Sloan, H.; Pik, R.; Ahmed, A.; Khanbari, K.


    Transfer zones are ubiquitous features in continental rifts and margins, as are transform faults in oceanic lithosphere. Here, we present a structural study of the Hadibo Transfer Zone (HTZ), located in Socotra Island (Yemen) in the southeastern Gulf of Aden. There, we interpret this continental transfer fault zone to represent a reactivated pre-existing structure. Its trend is oblique to the direction of divergence and it has been active from the early up to the latest stages of rifting. One of the main oceanic fracture zones (FZ), the Hadibo-Sharbithat FZ, is aligned with and appears to be an extension of the HTZ and is probably genetically linked to it. Comparing this setting with observations from other Afro-Arabian rifts as well as with passive margins worldwide, it appears that many continental transfer zones are reactivated pre-existing structures, oblique to divergence. We therefore establish a classification system for oceanic FZ based upon their relationship with syn-rift structures. Type 1 FZ form at syn-rift structures and are late syn-rift to early syn-OCT. Type 2 FZ form during the OCT formation and Type 3 FZ form within the oceanic domain, after the oceanic spreading onset. The latter are controlled by far-field forces, magmatic processes, spreading rates, and oceanic crust rheology.

  3. Marginal zone B-cell lymphoma with multiple extranodal locations in a patient with Sjögren’s syndrome – a diagnostic problem

    Directory of Open Access Journals (Sweden)

    Marta Domżalska


    Full Text Available Sjögren’s syndrome is a chronic autoimmune disease characterized by the presence of lymphocytic infiltrates in exocrine glands, mainly salivary and lacrimal glands, which result in xerophthalmia and xerostomia. About half of the patients develop systemic complications, including lymphoproliferative disorders. We report a case of a 27-year-old woman with a diagnosis of Sjögren’s syndrome and a suspicion of respiratory system involvement in the course of granulomatosis with polyangiitis. Histopathological examination of a skin lesion suggested marginal zone B-cell lymphoma. After pathological and immunohistochemical evaluation of all available previous biopsy samples and the medical documentation the diagnosis of extranodal marginal zone B-cell lymphoma stage IV according to the Ann Arbor classification was rendered. The patient was referred to the Department of Haematology and was treated with R-CVP (cyclophosphamide, vincristine, prednisone, rituximab.

  4. Shifts in Köppen-Geiger climate zones over southern Africa in relation to key global temperature goals (United States)

    Engelbrecht, Christien J.; Engelbrecht, Francois A.


    Potential changes in Köppen-Geiger climate zones over southern Africa (Africa south of 22 °S) under future climate change are investigated using an ensemble of high-resolution projections of a regional climate model. The projections are performed under the A2 scenario of the Special Report on Emission Scenarios (SRES), and changes are presented for those times in the future when the increase in global average surface temperature reaches thresholds of 1, 2, and 3 °C, relative to the present-day baseline climatology. Widespread shifts in climate regimes are projected, of which the southern and eastern expansion of the hot desert and hot steppe zones is the most prominent. From occupying 33.1 and 19.4 % of southern Africa under present-day climate, these regions are projected to occupy between 47.3 and 59.7 % (hot desert zone) and 24.9 and 29.9 % (hot steppe zone) of the region in a future world where the global temperature has increased by 3 °C. The cold desert and cold steppe zones are projected to decrease correspondingly. The temperate regions of eastern South Africa, the Cape south coast, and winter rainfall region of the southwestern Cape are also projected to contract. An expansion of the hot steppe zone into the cold steppe and temperate zones may favor the intrusion of trees (and therefore the savanna biome) into the most pristine grasslands of southern Africa. However, the correlative climate-vegetation approach of using projected changes in Köppen-Geiger zones to infer future vegetation patterns is of limited value in the savanna complex of southern Africa, where complex feedbacks occur between carbon dioxide (CO2) concentrations, trees, C4 grasses, fire, and climate. The present-day temperate Cape Fynbos regime may come under increasing pressure as the encompassing temperate zone is invaded mainly from the east by the hot steppe climate regime under climate change, with the incidence of Fynbos fires also becoming more likely in a generally warmer and

  5. Investigation of Along-Arc Geochemical Variations in the Southern Volcanic Zone: Azufre-Planchon-Peteroa Volcanic Complex, Southern Chile (United States)

    Holbik, S. P.; Hickey-Vargas, R.; Tormey, D.


    The Andean Southern Volcanic Zone (SVZ) is a vast and complex continental arc that has been studied extensively to provide an understanding of arc-magma genesis, the origin and chemical evolution of the continental crust, and geochemical compositions of volcanic products. This study focuses on volcanic rocks from the Azufre-Planchon-Peteroa (APP 35°15'S) volcanic complex, within the Transitional SVZ (34.3-37.0 °S), where crustal thickness increases from approximately 30 km in the south (Central SVZ), to 55 km in the north (Northern SVZ). Planchon is the northernmost volcano in the SVZ to erupt basaltic products, while Peteroa is the currently active cone, erupting tephra of andesitic composition, most recently in September of 2011. New data for the APP are consistent with the hypothesis of Tormey et al. (1995) that the APP experienced variable depths of crystal fractionation, and that crustal assimilation at Planchon is restricted to the lower crustal depths, as reflected by limited variability in 87Sr/86Sr isotopes. New δ18O data (26.5‰) from an outcropping dolomitic limestone country rock in the vicinity of the Azufre volcano also confirms the upper crustal source of anomalously high (7.1 and 7.3‰) oxygen isotopic values for Azufre dacites. A trend of high La/Yb (6.5-9.1) and Yb depletion with increasing La/Yb for Planchon basalts is consistent with the role of garnet as a residual or crystallizing phase at lower crustal depths, however, the La/Yb range is small when compared to published data from nearby TSVZ centers such as Nevado de Longavi (La/Yb = 5.5 to 16.7) and San Pedro Pellado (La/Yb =7.2 to 13.6). Geochemical modeling of the Planchon data shows that both hornblende and garnet must be involved in the magmatic evolution, even though erupted basalts are free of major hydrous phases, in order to account for the more limited range of La/Yb. Interestingly, baseline values of La/Yb for basalt and basaltic andesites from throughout the TSVZ, including

  6. The southern Sierra Nevada Frontal Fault Zone: what longitudinal stream profiles tell us about fault evolution and the presence of relay zone structures (United States)

    Koehler, K.; Krugh, W. C.


    The mechanical linkage of normal faults can result in spatial variations in fault displacement. In this study we use ArcGIS®, Matlab®, and software from to perform stream profile analysis along the southern Sierra Nevada Frontal Fault Zone (SNFFZ). This work aims to constrain the pattern of rock uplift and identify potential relay zone structures associated with fault evolution. Stream profile analysis is suitable for this investigation since the fluvial network upholds a continuous connection to the driving forces of tectonics. For this study we expect to find higher channel steepness indices and rates of rock uplift where the processes of mechanical fault linkage have occurred most recently. Using a 10m digital elevation model from the USGS, watershed boundaries and longitudinal stream profiles were extracted for divide reaching, and select non-divide reaching, drainages along the footwall of the southern SNFFZ. The relationship between channel slope and contributing drainage area for each watershed was then used to determine an average channel concavity, and to specify a regional reference concavity of θref = 0.695. This information was used to calculate the normalized steepness index for each watershed. Preliminary findings, using an initial θref = 0.45, indicated that the max channel steepness occurs at Cottonwood Creek, which drains much of the relay zone, with ksn values decreasing in both directions along strike. With further analyses using θref = 0.695, it is evident that anomalous values of ksn are present around the Cottonwood Creek drainage, and near Sawmill Creek to the north. Knickpoint examination shows that a prominent trend exists within the southern catchments, while north of Cottonwood Creek knickpoint elevations are highly erratic. Interpretation of this suggests that the southern knickpoints hold greater value for tectonic analyses. The findings of this study provide evidence that relay zone structures are potentially

  7. Distinctive Features of the Human Marginal Zone and Cajal-Retzius Cells: Comparison of Morphological and Immunocytochemical Features at Midgestation.

    Directory of Open Access Journals (Sweden)

    Lyubov Aleksandrovna Tkachenko


    Full Text Available Despite a long history of research of cortical marginal zone (MZ organization and development, a number of issues remain unresolved. One particular issue is the problem of Cajal-Retzius cells (C‑R identification. It is currently based on morphology and Reelin expression. The aim of this research is to investigate MZ cytoarchitectonics and Reelin-producing cells morphotypes in the superior temporal, pre- and postcentral cortex at GW24-26. We used Reelin (Reln as the marker for Cajal-Retzius cells and microtubule-associated protein 2 (MAP2 and neurofilament heavy chain protein (N200 as markers of neuronal maturation. The MZ of all of the investigated areas had the distinct cytoarchitectonic of alternating cell sparse (MZP, SR and cell dense (SGL, DGL layers. The distribution of the neuromarkers across the MZ also showed layer specificity. MAP2-positive cells were only found in the SGL. N200 and Reelin-positive neurons in the MZP. N200-positive processes were forming a plexus at the DGL level. All of the N200-positive neurons found were in the MZP and had distinctive morphological features of C‑R cells. All of the N200-positive neurons in MZ were also positive for Reelin, whereas MAP2-positive cells lack Reelin. Thus, the joint use of two immunomarkers allowed us to discern the C‑R cells based on their morphotype and neurochemistry and indicate that the Reelin-positive cells of MZ at 24-26 GW were morphologically C‑R cells. In the current study, we identified three C‑R cells morphotypes. Using a 3D reconstruction, we made sure that all of them belonged to the single morphotype of triangular C‑R cells. This approach will allow future studies to separate C‑R cells from other Reelin-producing neurons which appear at later corticogenesis stages. In addition, our findings support the assumption that a plexus could be formed not only with C‑R cells processes but also possibly by other cell processes by the poorly researched DGL, which is

  8. A synthesis of Jurassic and Early Cretaceous crustal evolution along the southern margin of the Arctic Alaska–Chukotka microplate and implications for defining tectonic boundaries active during opening of Arctic Ocean basins (United States)

    Till, Alison B.


    A synthesis of Late Jurassic and Early Cretaceous collision-related metamorphic events in the Arctic Alaska–Chukotka microplate clarifies its likely movement history during opening of the Amerasian and Canada basins. Comprehensive tectonic reconstructions of basin opening have been problematic, in part, because of the large size of the microplate, uncertainties in the location and kinematics of structures bounding the microplate, and lack of information on its internal deformation history. Many reconstructions have treated Arctic Alaska and Chukotka as a single crustal entity largely on the basis of similarities in their Mesozoic structural trends and similar late Proterozoic and early Paleozoic histories. Others have located Chukotka near Siberia during the Triassic and Jurassic, on the basis of detrital zircon age populations, and suggested that it was Arctic Alaska alone that rotated. The Mesozoic metamorphic histories of Arctic Alaska and Chukotka can be used to test the validity of these two approaches.A synthesis of the distribution, character, and timing of metamorphic events reveals substantial differences in the histories of the southern margin of the microplate in Chukotka in comparison to Arctic Alaska and places specific limitations on tectonic reconstructions. During the Late Jurassic and earliest Cretaceous, the Arctic Alaska margin was subducted to the south, while the Chukotka margin was the upper plate of a north-dipping subduction zone or a zone of transpression. An early Aptian blueschist- and greenschist-facies belt records the most profound crustal thickening event in the evolution of the orogen. It may have resulted in thicknesses of 50–60 km and was likely the cause of flexural subsidence in the foredeep of the Brooks Range. This event involved northern Alaska and northeasternmost Chukotka; it did not involve central and western Chukotka. Arctic Alaska and Chukotka evolved separately until the Aptian thickening event, which was likely a

  9. Lithospheric delamination in post-collisional setting: Evidence from intrusive magmatism from the North Qilian orogen to southern margin of the Alxa block, NW China (United States)

    Zhang, Liqi; Zhang, Hongfei; Zhang, Shasha; Xiong, Ziliang; Luo, Biji; Yang, He; Pan, Fabin; Zhou, Xiaochun; Xu, Wangchun; Guo, Liang


    Post-collisional granitoids are widespread in the North Qilian and southern margin of the Alxa block and their petrogenesis can provide important insights into the lithospheric processes in a post-collisional setting. This paper carries out an integrated study of U-Pb zircon dating, geochemical and Sr-Nd-Hf isotopic compositions for five early Paleozoic intrusive plutons from the North Qilian to southern margin of the Alxa block. The geochronological and geochemical results show that their magmatism can be divided into three periods with distinct geochemical features. The early-period intrusive rocks ( 440 Ma) include the Lianhuashan (LHS) and Mengjiadawan (MJDW) granodiorites. Both of them display high Sr/Y ratios (52-91), coupled with low Y and HREE contents, implying that they were derived from partial melting of thickened lower crust, with garnet in the residue. The middle-period intrusive rocks ( 430 Ma), including the MJDW quartz diorites and Yangqiandashan (YQDS) granodiorites, are high-K calc-alkaline with low Sr/Y values. The geochemical and isotopic data suggest that they are generated from partial melting of lower crust without garnet in the residue. The late-period intrusive rocks (414-422 Ma), represented by the Shengrongsi (SRS) and Xinkaigou (XKG) plutons, are A-type or alkali-feldspar granites. They are possibly derived from partial melting of felsic crustal material under lower pressure condition. Our data show decreasing magma crystallization ages from MJDW pluton in the north and LHS pluton in the south to the SRS and XKG plutons in the central part of the study area. We suggest that such spatial and temporal variations of magmatic suites were caused by lithospheric delamination after the collision between the Central Qilian and the Alxa block. A more plausible explanation is that the delamination propagated from the margin part of the thickened lithosphere to inward beneath the North Qilian and southern margin of the Alxa block.

  10. Is the Vincent fault in southern California the Laramide subduction zone megathrust? (United States)

    Xia, H.; Platt, J. P.


    The Vincent fault (VF) in the San Gabriel Mountains, southern California separates a Meso-Proterozoic gneiss complex and Mesozoic granitoid rocks in the upper plate from the ocean-affiliated Late Cretaceous Pelona schist in the lower plate, and it has been widely interpreted as the original Laramide subduction megathrust. A 500 to 1000 m thick mylonite zone, consisting of a low-stress (LS) section at the bottom, a high-stress (HS) section at the top, and a weakly deformed section in between, is developed above the VF. Our kinematic, thermobarometric and geochronological analysis of the mylonite zone indicates that the VF is a normal fault. Shear sense indicators including asymmetric porphyroblasts, quartz new grain fabric, mineral fish, and quartz CPO from the HS and the LS sections exhibit a top-to-SE sense of shear on the SW-dipping mylonitic foliation, which is contrary to what one would expect for the Laramide subduction megathrust. A few samples from the LS section were overprinted by HS microstructure, implying that the LS mylonites predate the HS mylonites. TitaniQ thermometer and Si-in-muscovite barometer show that the P-T conditions are 389 ± 6 °C, 5 kbar for the LS mylonites and 329 ± 6 °C, 2.4 kbar for HS mylonites. Considering the temporal sequence of HS and LS mylonites, they are likely to be formed during exhumation. A comparison with the lower plate leads to the same conclusion. The top 80-100 m of the Pelona schist underneath the VF is folded and also mylonitized, forming the Narrows synform and S3 simultaneously. Our previous study found that S3 of the Pelona schist has a top-to-SE sense of shear and similar P-T conditions as the LS mylonite in the upper plate, so S3 of the Pelona schist is likely to be formed together with the LS mylonites in the upper plate. While mylonitization of Pelona schist (S3) overprinted both the subduction-related S1 fabric and the return-flow-related S2 fabric, it is reasonable to argue that the mylonite zone above

  11. Wave-induced bedload transport – a study of the southern Baltic coastal zone

    Directory of Open Access Journals (Sweden)

    Dudkowska Aleksandra


    Full Text Available The wave-induced bedload transport and spatial distribution of its magnitude in the southern Baltic coastal zone of Poland are estimated. The vicinity of Lubiatowo was selected as a representative part of the Polish coast. It was assumed that transport is a function of shear stress; alternative approaches, based on force balances and discharge relationships, were not considered in the present study. Four models were studied and compared over a wide range of bottom shear stress and wind-wave conditions. The set of models comprises classic theories that assume a simplified influence of turbulence on sediment transport (e.g., advocated by authors such as Du Boys, Meyer-Peter and Müller, Ribberink, Engelund and Hansen. It is shown that these models allow to estimate transport comparable to measured values under similar environmental conditions. A united general model for bedload transport is proposed, and a set of maps of wave bedload transport for various wind conditions in the study area is presented.

  12. Invasion of alien plants in fire-damaged forests at southern boundary of the taiga zone

    Energy Technology Data Exchange (ETDEWEB)

    Khapugin, A.A.; Vargot, E.V.; Chugunov, G.G.; Shugaev, N.I.


    Aim of the study: Biological invasions are one of the most important areas of forest research. In this study, we revealed invasibility of fire-damaged forests at the southern boundary of the taiga zone. Area of study: The Mordovia State Nature Reserve (Central Russia). Material and Methods: Altogether, 11 square plots of each 100 ×100 m were established in different types of fire-damaged forests. To test plant invasion outside the established plots, field researches were carried out by route method in fire-damaged area of the Mordovia Reserve. Main Results: Six alien species (Erigeron canadensis, E. annuus, Oenothera biennis, Lactuca serriola, Sambucus racemosa, Viola arvensis) were registered within the established plots in 2011–2014. In addition, two alien invasive plants (Solidago canadensis and Bidens frondosa) were found outside these plots. No differences were detected in invasibility of the tested forest ecosystems. Research highlights: Among the revealed alien species, Erigeron canadensis, Lactuca serriola and Solidago canadensis are the most invasive plants in forest ecosystems. The first one was observed with a high occurrence frequency and abundance in all forest types tested. The second one has not been differed by abundance, but it characterized by a high competition as well as a large biomass and a large number of seeds. Solidago canadensis penetrated to natural forest ecosystem in a short time period due to closest location of its dispersal centers near the boundary of the Mordovia Reserve. These species are the most probable invaders of the forest ecosystems. (Author)

  13. Prevalence and zoonotic aspects of small ruminant mange in the lateritic and waterlogged zones, southern Benin

    Directory of Open Access Journals (Sweden)

    Sahidou Salifou

    Full Text Available An epidemiological survey was undertaken from March to September 2010 to assess the prevalence and zoonotic aspects of scabies in small ruminants in two agro-ecological zones in southern Benin. Small ruminant (n = 444 smallholders and 1,807 of their animals (1,233 West African dwarf goats and 574 West African dwarf sheep were included in the study. The animals underwent physical examination and, when scabies-like lesions were found, crusts and integument scrapings were collected for microscopic parasitological tests. The samples collected in each survey were coded in accordance with the owner-animal pairings in order to assess the degree of correlation between mange cases in humans (smallholders and their animals. The overall prevalence of scabies was 28.33% and 9.5% in animals and smallholders (human cases respectively. Infestations were significantly (p < 0.001 more frequent in goats (39.6% than in sheep. The uniqueness of the etiological agent (Sarcoptes scabiei, the very high predictive value of human scabies in infected farms (83.67% and a very high odds ratio (OR = 2,019.25 indicate that small ruminant scabies has been transmitted to smallholders by their animals. Close contact between these smallholders and their animals was a determining factor in this interspecies communicability of sarcoptic mange.

  14. Miocene uplift of the NE Greenland margin linked to plate tectonics: Seismic evidence from the Greenland Fracture Zone, NE Atlantic

    DEFF Research Database (Denmark)

    Døssing Andreasen, Arne; Japsen, Peter; Watts, Anthony B.


    Tectonic models predict that, following breakup, rift margins undergo only decaying thermal subsidence during their post-rift evolution. However, post-breakup stratigraphy beneath the NE Atlantic shelves shows evidence of regional-scale unconformities, commonly cited as outer margin responses to ...... by plate tectonic forces, induced perhaps by a change in the Iceland plume (a hot pulse) and/or by changes in intra-plate stresses related to global tectonics....

  15. A reworked Lake Zone margin: Chronological and geochemical constraints from the Ordovician arc-related basement of the Hovd Zone (western Mongolia)

    Czech Academy of Sciences Publication Activity Database

    Soejono, I.; Buriánek, D.; Janoušek, V.; Svojtka, Martin; Čáp, P.; Erban, V.; Ganpurev, D.

    294/295, December (2017), s. 112-132 ISSN 0024-4937 Institutional support: RVO:67985831 Keywords : Ordovician magmatic arc * Mid-Silurian intra-plate magmatism * Hovd Zone * Reworked Lake Zone Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.677, year: 2016

  16. An Unusual Case of Marginal Zone B-Cell Lymphoma Arising in the Breast - Its Diagnosis and the Role of Radiotherapy in its Management.

    LENUS (Irish Health Repository)

    Rock, Kathy


    BACKGROUND: Primary lymphoma of the breast accounts for 0.04-0.5% of all breast malignancies and approximately 1% of all extranodal lymphomas. For stage IE node-negative disease, involved field radiotherapy is recommended except for very young women in whom the risk of breast cancer is a concern. The rate of complete response for limited stage extranodal marginal B-cell lymphoma is in excess of 90%. CASE REPORT: We report the case of a 62-year-old lady who presented with a unilateral painless palpable right breast lump. She subsequently underwent a trucut biopsy of the lesion. The histology revealed a low-grade B-cell non-Hodgkin\\'s lymphoma (NHL). Immunohistochemistry showed that more than 95% of the cells were B cells which were CD 20+\\/CD 45+ and BC L6+. This confirmed the diagnosis of marginal zone lymphoma. Staging work-up was negative for distant metastases. Serum alkaline phosphatase and lactate dehydrogenase were normal. The patient had no \\'B\\' symptoms. Her final diagnosis was clinical stage IAE NHL, and she was referred for curative radiotherapy. CONCLUSION: Radiation treatment is a safe and extremely effective modality of treatment for early stage I marginal zone B-cell lymphomas of the breast.

  17. Heat Flow Assesment From Bottom Simulating Reflector and Its Evolution Along The Southern Colombian Convergent Margin (1.5 To 3.5°n). (United States)

    Marcaillou, Boris; Yves Collot, Jean; Spence, Georges; Wang, Kelin

    Several multichannel seismic profiles acquired during the Sisteur experiment, across the Colombia convergent margin, exhibit well identified Bottom Simulating Reflectors (BSRs). These BSRs, controlled by temperature and pressure conditions, coincide with the base of the gas hydrate stability field. Thus BSRs can be used to assess heat flow and hence the thermal regime of the Colombian margin. The BSRs show a negative polarity and extend to depths of 0.15 s below the seafloor (bsf) on the upper margin (~800 m of water depth) and to 0.78 s bsf at trench depths (3800 m). We assumed a purely conductive model to determine heat flow and its variation across the Colombian margin. The seafloor temperature was obtained from local CTD measurements and the thermal conductivity of the sediments was extrapolated from ODP Leg112 offshore Peru. BSRs are clearly identified along several dip and strike seismic lines. The heat flow values inferred from the BSR picks range between 30-40 mW/m2 along the middle and upper margin slopes, whereas these heat flow values increase to 80-100 mW/m2 close to the trench. Mapping these heat flow values exhibits important thermal variations along the Colombian margin. These variations could be accounted by the variating age of the crust from north to south, the different thicknesses of the trench sedimentary layer between the profiles or by the crustal structure complexity. The thermal modeling allowed us to obtain approximate temperatures along the top of the subducting Nazca plate. This late Miocene plate is considered as the main thermal source because the interpreted ophiolitic nature of the margin is believed to have negligible radiogenic heat production. The model integrates a 5 cm/year plate convergence rate and the margin structures as obtained from the SISTEUR multichannel seismic reflection and refraction data. The thermal parameters, in this model, were inferred from the rocks type within each layer. Temperatures at the top of the

  18. Holocene late Pleistocene non-tropical carbonate sediments and tectonic history of the western rift basin margin of the southern Gulf of California (United States)

    Halfar, Jochen; Godinez-Orta, Lucio; Goodfriend, Glenn A.; Mucciarone, David A.; Ingle, James C.; Holden, Peter


    Using high-resolution seismic reflection profiling and dating of (1) shallow marine vibracores and (2) sediments collected from uplifted marine terraces we reconstruct the tectonic history and sediment accumulation patterns of Holocene to late Pleistocene warm-temperate to subtropical carbonates in the southern Gulf of California, Mexico. The study was conducted in the vicinity of La Paz where carbonates form along the fault bounded narrow western shelf of the tectonically active Gulf of California rift basin. The non-tropical nature of the setting is responsible for (1) poor cementation of the bioclastic carbonates, and (2) a composition which is dominated by rhodoliths (coralline red algae), corals and mollusks. Unrimmed carbonate flats forming in small pocket bays and a rhodolith bioherm, which has a surface area of more than 20 km2 and is up to 16 m thick, constitute the major carbonate factories. Holocene carbonate accumulation rates were deduced from seismic and core data and are highest on the rhodolith bioherm (260 cm/ka) and in subtidal zones of pocket bays (210 cm/ka), and lowest on the inner and middle shelf (100 cm/ka). Taken together, rates of carbonate accumulation are intermediate in magnitude between higher rates recorded in fully tropical carbonate settings and lower rates typical of cool-water carbonates. Seismic reflection profiles demonstrate that Isla Espiritu Santo in the center of the study area is a west dipping fault block, which is tectonically influenced by two distinct faults, the La Paz and Espiritu Santo faults. The latter fault accommodates at least 700 m of east-side down normal offset, and forms a steep eastern escarpment leading into the La Paz slope basin. Some of the sediments produced in the shallow carbonate factories of the narrow La Paz shelf are transported across this escarpment and are redeposited in the slope basin at a water depth of 750 m. Uranium-series dates of marine terraces exposed on Isla Espiritu Santo indicate

  19. Coastal zone color scanner pigment concentrations in the Southern Ocean and relationships to geophysical surface features (United States)

    Comiso, J. C.; McClain, C. R.; Sullivan, C. W.; Ryan, J. P.; Leonard, C. L.


    The spatial and seasonal distributions of phytoplankton pigment concentration over the entire southern ocean have been studied for the first time using the coastal zone color scanner historical data set (from October 1978 through June 1986). Enhanced pigment concentrations are observed between 35°S and 55°S throughout the year, with such enhanced regions being more confined to the south in the austral summer and extending further north in the winter. North and south of the polar front, phytoplankton blooms (>1 mg/m3) are not uniformly distributed around the circumpolar region. Instead, blooms appear to be located in regions of ice retreat (or high melt areas) such as the Scotia Sea and the Ross Sea, in relatively shallow areas (e.g., the Patagonian and the New Zealand shelves), in some regions of Ekman upwelling like the Tasman Sea, and near areas of high eddy kinetic energy such as the Agulhas retroflection. Among all features examined by regression analysis, bathymetry appears to be the one most consistently correlated with pigments (correlation coefficient being about -0.3 for the entire region). The cause of negative correlation with bathymetry is unknown but is consistent with the observed abundance of iron in shallow areas in the Antarctic region. It is also consistent with resuspension of phytoplankton cells by wind-induced mixing, especially in shallow waters. On the other hand, in the deep ocean (especially at latitudes nutrients may be limiting), upwelling induced by topographic features may cause resupply of nutrients to the surface and shoaling of the subsurface chlorophyll maximum. Low pigment values are common at low latitudes and in regions of high wind stress, where deep mixing and net loss of surface pigment occur. Nutrients (phosphate, nitrate, and silicate) are found to correlate significantly with pigments when the entire southern ocean is considered, but south of 55°S the correlation is poor, probably because the Antarctic waters are not

  20. Status of bovine tuberculosis and its zoonotic implications in Borana zone, Southern Ethiopia. (United States)

    Duguma, Ararsa; Abera, Shubisa; Zewdie, Wubishet; Belina, Dinaol; Haro, Godana


    A cross-sectional study was carried out from April 2015 to June 2016 to estimate the status of bovine tuberculosis (BTB), assessment of community's current knowledge, and zoonotic importance on this disease in Borana zone, southern Ethiopia. In this study, comparative intradermal tuberculin (CIDT) test, structured questionnaires, and retrospective data were used, while the result indicated 3.8% prevalence at individual animal level with 5.6% (31/554) of doubtful reactors. Among related risk factors included, old animals were significantly infected by BTB than young one (χ 2  = 32.005, P = 0.001). Parity number again showed significant difference (χ 2  = 29.163, P = 0.001) where animals with many parity were more reactive to conducted test than few parity numbers. Animals born in the breeding center managed under semi-intensive production system were more infected (χ 2  = 10.795, P = 0.029) than those brought from outside of the center. Questionnaire survey in this study indicated that out of 130 interviewed respondents, only 30% pastoralists knew what BTB mean; whereas the level of individual knowledge from interviewed showed about 72.3% of respondents had poor understanding of BTB and only about 11.5% of them knew its zoonotic importance. Meat eating habit of communities in the area were culturally inhabited to eat cooked meat and only 12.3% (16/130) of respondents gave response on habit of eating both raw and cooked meat. Milk drinking habit of pastoralist in the area showed about 79.2% drunk raw milk and the rest 20.8% used both raw and boiled milk. A retrospective data from Yabello Hospital indicated that current prevalence of human TB as 38.79% and showing the disease was highly increasing from year to year in the study area. This implies a great importance of human tuberculosis and its future concern in Borana zone. From this, there should be detail awareness of communities on BTB, its zoonotic importance, and the need of further

  1. Spatio-temporal analysis of smear-positive tuberculosis in the Sidama Zone, southern Ethiopia.

    Directory of Open Access Journals (Sweden)

    Mesay Hailu Dangisso

    Full Text Available Tuberculosis (TB is a disease of public health concern, with a varying distribution across settings depending on socio-economic status, HIV burden, availability and performance of the health system. Ethiopia is a country with a high burden of TB, with regional variations in TB case notification rates (CNRs. However, TB program reports are often compiled and reported at higher administrative units that do not show the burden at lower units, so there is limited information about the spatial distribution of the disease. We therefore aim to assess the spatial distribution and presence of the spatio-temporal clustering of the disease in different geographic settings over 10 years in the Sidama Zone in southern Ethiopia.A retrospective space-time and spatial analysis were carried out at the kebele level (the lowest administrative unit within a district to identify spatial and space-time clusters of smear-positive pulmonary TB (PTB. Scan statistics, Global Moran's I, and Getis and Ordi (Gi* statistics were all used to help analyze the spatial distribution and clusters of the disease across settings.A total of 22,545 smear-positive PTB cases notified over 10 years were used for spatial analysis. In a purely spatial analysis, we identified the most likely cluster of smear-positive PTB in 192 kebeles in eight districts (RR= 2, p<0.001, with 12,155 observed and 8,668 expected cases. The Gi* statistic also identified the clusters in the same areas, and the spatial clusters showed stability in most areas in each year during the study period. The space-time analysis also detected the most likely cluster in 193 kebeles in the same eight districts (RR= 1.92, p<0.001, with 7,584 observed and 4,738 expected cases in 2003-2012.The study found variations in CNRs and significant spatio-temporal clusters of smear-positive PTB in the Sidama Zone. The findings can be used to guide TB control programs to devise effective TB control strategies for the geographic areas

  2. Determinants of use of health facility for childbirth in rural Hadiya zone, Southern Ethiopia. (United States)

    Asseffa, Netsanet Abera; Bukola, Fawole; Ayodele, Arowojolu


    Maternal mortality remains a major global public health concern despite many international efforts. Facility-based childbirth increases access to appropriate skilled attendance and emergency obstetric care services as the vast majority of obstetric complications occur during delivery. The purpose of the study was to determine the proportion of facility delivery and assess factors influencing utilization of health facility for childbirth. A cross-sectional study was conducted in two rural districts of Hadiya zone, southern Ethiopia. Participants who delivered within three years of the survey were selected by stratified random sampling. Trained interviewers administered a pre-tested semi-structured questionnaire. We employed bivariate analysis and logistic regression to identify determinants of facility-based delivery. Data from 751 participants showed that 26.9% of deliveries were attended in health facilities. In bivariate analysis, maternal age, education, husband's level of education, possession of radio, antenatal care, place of recent ANC attended, planned pregnancy, wealth quintile, parity, birth preparedness and complication readiness, being a model family and distance from the nearest health facility were associated with facility delivery. On multiple logistic regression, age, educational status, antenatal care, distance from the nearest health facility, wealth quintile, being a model family, planned pregnancy and place of recent ANC attended were the determinants of facility-based childbirth. Efforts to improve institutional deliveries in the region must strengthen initiatives that promote female education, opportunities for wealth creation, female empowerment and increased uptake of family planning among others. Service related barriers and cultural influences on the use of health facility for childbirth require further evaluation.

  3. On the distribution of silicic acid as a frontal zone tracer in the Indian sector of the Southern Ocean

    Directory of Open Access Journals (Sweden)

    R. Prego


    Full Text Available The subantarctic frontal zone surveyed during the April-May 1991 SUZIL cruise in the Crozet-Kerguelen-Amsterdam area shows a strong horizontal (north to south gradient of dissolved silicate, increasing with depth, from 5 to 10 µmolSi kg-1 at 100 m, and 10 to 70 µmolSi kg-1 at 600 m. The northern limit of this frontal zone, which is formed by the confluence of the Subtropical and Subantarctic Fronts, is delimited at the surface by the 2 µmolSi kg-1 silicate isoline. Silicate-salinity diagrams also allow different water regimes to be positioned relative to the frontal zone. This sloping interface is between two water bodies, one to the north with more saline subtropical waters of less concentrated silicate than the southern one, corresponding to subantarctic waters which are less saline and richer in silicate. It is concluded that dissolved silicate can be used as a useful tracer of frontal zone water masses in the Indian sector of the Southern Ocean, providing a sound complement to other hydrographic data.

  4. Tectonic lineaments in the cenozoic volcanics of southern Guatemala: Evidence for a broad continental plate boundary zone (United States)

    Baltuck, M.; Dixon, T. H.


    The northern Caribbean plate boundary has been undergoing left lateral strike slip motion since middle Tertiary time. The western part of the boundary occurs in a complex tectonic zone in the continental crust of Guatemala and southernmost Mexico, along the Chixoy-Polochic, Motogua and possibly Jocotan-Chamelecon faults. Prominent lineaments visible in radar imagery in the Neogene volcanic belt of southern Guatemala and western El Salvador were mapped and interpreted to suggest southwest extensions of this already broad plate boundary zone. Because these extensions can be traced beneath Quaternary volcanic cover, it is thought that this newly mapped fault zone is active and is accommodating some of the strain related to motion between the North American and Caribbean plates. Onshore exposures of the Motoqua-Polochic fault systems are characterized by abundant, tectonically emplaced ultramafic rocks. A similar mode of emplacement for these off shore ultramafics, is suggested.

  5. Thermal Structure of the Cascadia Subduction Zone on the Washington Margin (AT26-04, EM122) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We propose to conduct a comprehensive study of the thermal environment of the Cascadia Subduction Zone (CSZ) within the NSF GeoPRISM Corridor off the Washington...

  6. Contribution to the Triassic ostracode faunas of the Betic Zone (southern Spain)

    NARCIS (Netherlands)

    Kozur, H.; Kampschuur, W.; Mulder-Blanken, C. W. H.; Simon, O.J.


    Ostracodes are reported for the first time from epimetamorphic, strongly tectonized Triassic rock sequences from the internal part of the Betic Cordilleras. Three ostracode-zones have been established. The lower and middle zones are attributed to the Late Ladinian (Longobardian) and the upper zone

  7. Sedimentary pigments and nature of organic matter within the oxygen minimum zone (OMZ) of the Eastern Arabian Sea (Indian margin)

    Digital Repository Service at National Institute of Oceanography (India)

    Rasiq, K.T.; Kurian, S.; Karapurkar, S.G.; Naqvi, S.W.A.

    al., 2002). The comparative lability and source specificity makes them a powerful tool used to investigate many aspects of benthic biogeochemical processes as well as OM source and history (Jeffrey and Vesk, 1997; Boon and Duineveld, 1998... pigments. The absence of β- carotene at 1100m site may be due to its degradation through a sequence of transformation reactions possibly initiated by epoxidation as described by Repeta and Gagosian (1984) from the Peru margin sediments. The decreasing...

  8. Chlorophyll-a Variability in the Southern Ocean Mixed Layer and Euphotic Zone From Elephant Seals and Profiling Floats (United States)

    Carranza, M. M.; Gille, S. T.; Franks, P. J. S.; Johnson, K. S.; Girton, J. B.


    The Southern Ocean contains some of the ocean's deepest mixed layers. Because deep mixed layers can transport phytoplankton below the euphotic zone, light levels depend on mixed-layer depth (MLD), and phytoplankton growth is hypothesized to be co-limited by iron and light. Estimates of Chl-a fluorescence, particle backscattering and hydrographic profiles collected by southern elephant seals, EM-APEX, and biogeochemical Argo floats are used to evaluate the extent to which MLD influences phytoplankton bloom development and the vertical structure of chlorophyll-a (Chl-a) in the Southern Ocean. We find that surface Chl-a (i.e., mean Chl-a for the upper light penetration depth) is a relatively good proxy of phytoplankton biomass (i.e., depth-integrated Chl-a) within the euphotic zone but gives an inadequate representation of biomass within the mixed layer, particularly in the summer. Although nearly vertically homogeneous Chl-a within the mixed layer prevails in seasonal mean profiles, subsurface Chl-a maxima are not uncommon from spring through fall. Deep Chl-a maxima that correlate with particle backscattering in summer and fall are found near the base of the mixed layer, closer to the nutrient maximum than the light maximum, suggesting that nutrient limitation (i.e., essentially iron) can play a greater role than light limitation in governing productivity.

  9. Wetlands as principal zones of methylmercury production in southern Louisiana and the Gulf of Mexico region

    Energy Technology Data Exchange (ETDEWEB)

    Hall, B.D. [Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, WI 53706 (United States); Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK, S4S 0A2 (Canada)], E-mail:; Aiken, G.R. [United States Geological Survey, 3215 Marine Street, Boulder, CO 80303 (United States); Krabbenhoft, D.P. [United States Geological Survey, 8505 Research Way, Middleton, WI 53562 (United States); Marvin-DiPasquale, M. [United States Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025 (United States); Swarzenski, C.M. [United States Geological Survey, Suite 120, 3535 S. Sherwood Forest Blvd., Baton Rouge, LA 70816 (United States)


    It is widely recognized that wetlands, especially those rich in organic matter and receiving appreciable atmospheric mercury (Hg) inputs, are important sites of methylmercury (MeHg) production. Extensive wetlands in the southeastern United States have many ecosystem attributes ideal for promoting high MeHg production rates; however, relatively few mercury cycling studies have been conducted in these environments. We conducted a landscape scale study examining Hg cycling in coastal Louisiana (USA) including four field trips conducted between August 2003 and May 2005. Sites were chosen to represent different ecosystem types, including: a large shallow eutrophic estuarine lake (Lake Pontchartrain), three rivers draining into the lake, a cypress-tupelo dominated freshwater swamp, and six emergent marshes ranging from a freshwater marsh dominated by Panicum hemitomon to a Spartina alterniflora dominated salt marsh close to the Gulf of Mexico. We measured MeHg and total Hg (THg) concentrations, and ancillary chemical characteristics, in whole and filtered surface water, and filtered porewater. Overall, MeHg concentrations were greatest in surface water of freshwater wetlands and lowest in the profundal (non-vegetated) regions of the lake and river mainstems. Concentrations of THg and MeHg in filtered surface water were positively correlated with the highly reactive, aromatic (hydrophobic organic acid) fraction of dissolved organic carbon (DOC). These results suggest that DOC plays an important role in promoting the mobility, transport and bioavailability of inorganic Hg in these environments. Further, elevated porewater concentrations in marine and brackish wetlands suggest coastal wetlands along the Gulf Coast are key sites for MeHg production and may be a principal source of MeHg to foodwebs in the Gulf of Mexico. Examining the relationships among MeHg, THg, and DOC across these multiple landscape types is a first step in evaluating possible links between key zones for

  10. Critical zone weathering in the southern Sierra Nevada and Laramie Mountains imaged by seismic tomography (United States)

    Hayes, J. L.; Holbrook, W. S.; Riebe, C. S.


    Near-surface variations in seismic velocity reflect differences in physical properties such as density and porosity, which in turn reflect differences in alteration of parent material by exposure to water and biologic activity. Here we present tomographic analysis of the extent of weathering from seismic refraction experiments at two areas underlain by granite: the Southern Sierra Critical Zone Observatory (SSCZO) in the fall of 2010 & 2011 and the Laramie Mountains in the spring of 2010. A 48-channel geophone array and hammer source was deployed in both surveys. In both areas seismic velocities suggest that weathering has progressed to depths of 10 m or more. When coupled with geochemical measurements of the degree of regolith weathering, these depths imply that the potential for subsurface water storage in regolith may be a larger component of the water budget than previously thought at the SSCZO. The velocity of granite bedrock was determined independently in both studies to be ~4 km/s by seismic experiments directly on outcropping granite. Two other ranges of seismic velocities seem consistent between the studies: a saprolite layer of chemically altered but still intact rock (2-4 km/s) and a regolith layer more altered than the underlying saprolite layer (<2 km/s). Using these parameters we tested hypotheses in two different granite-weathering environments. In the SSCZO a velocity-depth profile that crosses a water-saturated meadow and an adjoining forest reveal relatively low gradients in the first ten meters beneath the forest (0.75 km/s per 10 m) and higher gradients beneath the meadow (3 km/s per 10 m). From these observations, we hypothesize that the saturated meadow may provide a reducing environment that inhibits chemical weathering relative to better-drained, more oxidizing conditions in the forest. In the 1.4 Ga Sherman batholith of the Laramie Mountains we observe isolated outcrops of Lincoln Granite within the Sherman Granite. Two 0.5 km profiles

  11. A Low Velocity Zone along the Chaochou Fault in Southern Taiwan: Seismic Image Revealed by a Linear Seismic Array

    Directory of Open Access Journals (Sweden)

    Hsin-Chieh Pu


    Full Text Available The Chaochou fault is one of the major boundary faults in southern Taiwan where strong convergence has taken place between the Eurasian and Philippine Sea plates. The surface fault trace between the Pingtung plain and the Central Range follows a nearly N-S direction and stretches to 80 km in length. In order to examine the subsurface structures along the Chaochou fault, a linear seismic array with 14 short-period stations was deployed across the fault to record seismic data between August and December 2001. Detailed examination of seismic data generated by 10 local earthquakes and recorded by the linear array has shown that the incidence angles of the first P-waves recorded by several seismic stations at the fault zone were significantly larger than those located farther away from the fault zone. This difference might reflect the lateral variation of velocity structures across the Chaochou fault. Further examination of ray-paths of seismic wave propagation indicates that a low-velocity zone along the Chaochou fault is needed to explain the significant change in incidence angles across the fault zone. Although we do not have adequate information to calculate the exact geometry of the fault zone well, the variation in incidence angles across the fault can be explained by the existence of a low-velocity zone that is about 3 km in width on the surface and extends downward to a depth of 5 km. The low-velocity zone along the Chaochou fault might imply that the fault system consists of several splay faults on the hanging wall in the Central Range.

  12. Thermochronology and Tectonics of the Leeward Antilles: evolution of the Southern Caribbean Plate Boundary Zone and accretion of the Bonaire Block (United States)

    van der Lelij, Roelant; Spikings, Richard; Kerr, Andrew; Kounov, Alexandre; Cosca, Michael; Chew, David; Villagomez, Diego


    Tectonic reconstructions of the Caribbean Plate are severely hampered by a paucity of geochronologic and exhumation constraints from anastomosed basement blocks along its southern margin. New zircon U/Pb, 40Ar/39Ar, apatite fission track and apatite (U-Th)/He data constrain quantitative thermal and exhumation histories, which have been used to propose a model for the tectonic evolution of the emergent parts of the Bonaire Block, and the Southern Caribbean Plate Boundary Zone. An east-facing arc system intruded through an oceanic plateau during ~90 to ~87 Ma, and crops out on Aruba. Subsequent structural displacements resulted in >80°C of cooling on Aruba during 70-60 Ma. In contrast, exhumation of the island arc sequence exposed on Bonaire occurred at 85-80 Ma and 55-45 Ma. Santonian exhumation on Bonaire occurred immediately subsequent to burial metamorphism and may have been driven by the collision of a west-facing island arc with the Caribbean Plate. Island-arc rocks intruded oceanic plateau rocks on Gran Roque at ~65 Ma and exhumed rapidly at 55-45 Ma. We attribute Maastrichtian - Danian exhumation on Aruba and early Eocene exhumation on Bonaire and Gran Roque to sequential diachronous accretion of their basement units to the South American Plate. Widespread unconformities indicate late Eocene subaerial exposure. Late Oligocene - early Miocene dextral transtension within the Bonaire block drove subsidence and burial of crystalline basement rocks of the Leeward Antilles to ≤1 km. Late Miocene - recent transpression caused inversion and ≤1 km of exhumation, possibly as a result of the northwards escape of the Maracaibo Block.

  13. Late Holocene and modern glacier changes in the marginal zone of Sólheimajökull, South Iceland

    DEFF Research Database (Denmark)

    Schomacker, Anders; Benediktsson, Ívar Örn; Ingólfsson, Ólafur


    The forefield of the Sólheimajökull outlet glacier, South Iceland, has a variety of glacial landforms and sediments that are products of late Holocene and modern glacier oscillations. Several sets of moraine ridges reflect past ice front positions and river-cut sedimentary sections provide inform...... the last 50 years. The glacier margin thickened 70-100 m from 1960 to 1996 and then thinned 120-150 m between 1996 and 2010. In 2010, the glacier snout was 20-40 m thinner than in 1960. Additionally, the DEM time-series detect areas of erosion and deposition in the forefield....

  14. Zoned amphibole in an eclogite from the Hida Marginal belt in the Hakuba district, Nagano Prefecture, Japan


    Takasu, Akira; Sakurai, Tsuyoshi; Kashiwabara, Y.; Minamide, Sachiyo


    A cobble-sized clast of eclogite was recently found in gravels in the bed of the Matsukawa River at Wadano in Hakuba village,Nagano Prefecture.The cobble was probably derived from an area in the Hida Marginal belt,which consists of high-pressure type schists and closely associated serpentinites,and also includes blocks of garnet glaucophane schist and garnet-epidote-glaucophane schist. The eclogite cobble consists mainly of garnet,omphacite,epidote and amphibole,along with small amounts of qu...

  15. Evolution of the broadly rifted zone in southern Ethiopia through gravitational collapse and extension of dynamic topography (United States)

    Emishaw, Luelseged; Laó-Dávila, Daniel A.; Abdelsalam, Mohamed G.; Atekwana, Estella A.; Gao, Stephen S.


    The Broadly Rifted Zone (BRZ) is a 315 km wide zone of extension in southern Ethiopia. It is located between the Southern Main Ethiopian Rift and the Eastern Branch of the East African Rift System (EARS) represented by the Kenya-Turkana Rift. The BRZ is characterized by NE-trending ridges and valleys superimposed on regionally uplifted ( 2 km average elevation) terrain. Previous studies proposed that the BRZ is an overlap zone resulted from northward propagation of the Kenya-Turkana Rift and southward propagation of the Southern Main Ethiopian Rift. To understand the relationship between the BRZ's extensional style and its crustal and upper mantle structures, this work first estimated the Moho depth using the two-dimensional (2D) radially-averaged power spectral analysis of the World Gravity Map. Verification of these results was accomplished through lithospheric-scale 2D forward gravity models along E-W profiles. This work found that the Moho topography beneath the BRZ depicts a dome-like shape with a minimum depth of 27 km in the center of the dome. This work proposes that the Moho doming, crustal arching underlying the BRZ and associated topographic uplift are the result of asthenospheric mantle upwelling beneath the BRZ. This upwelling changed to a NE-directed lateral mantle flow at shallower depth. This is supported by seismic tomography imaging which shows slow S-wave velocity anomaly at lithospheric depth of 75 km to 150 km stretching in a NE-SW direction from beneath the BRZ to the Afar Depression. This work proposes that the asthenospheric upwelling created gravitationally unstable dynamic topography that triggered extensional gravitational collapse leading to the formation of the BRZ as a wide rift within the narrow rift segments of the EARS.

  16. Study of channels and margins of milk commercialization at the highlands zone of Sugamuxi providence (Department of Boyacá

    Directory of Open Access Journals (Sweden)

    Paulo Rodríguez Romero


    Full Text Available The objective of the present study is to give information about the milk marketing characteristics in Sugamuxi province. The commercialization channels were identified and the commercial agents’ participation margins were established along with the current state of the links that form the production chain. Furthermore, the diffusion and application of the Treaty of Competitiveness of the Milk Sector (ACCL and of its system of prices were evaluated. This analysis discovered problems in two clearly defined areas based on topographical conditions (plain and hillside areas. They each present different problems and use different commercialisation channels. For this reason 235 surveys were given to the different links of the chain in each area. The commercialisation channel in plain areas is: producer, regional processors, wholesaler, consumer, and in hillside areas: producer, transporters, regional processor, local distributor and consumer. The commercialisation margins were calculated for raw milk, pasteurised milk and cheese. Because the profits are greater the great majority of producers in the plain areas are not applying the prices system. Furthermore, there is deficient knowledge of the ACCL on the part of the other links of the chain. Added to the small amount of information about the milk sector and the regional participants the development of a national competitive milk chain is blocked.

  17. Evolution of a Western Arctic Ice Ocean Boundary Layer and Mixed Layer Across a Developing Thermodynamically Forced Marginal Ice Zone (United States)


    in the Canada Basin seasonal ice zone. The subsections below outline the new contributions to the field of Arctic ice-ocean science discovered during...doi:10.1002/2013GL058956. Paulson, C.A. and W. S. Pegau, 2001: The summertime thermohaline evolution of an Arctic lead: Heat budget of the surface...Menge, 2010: Influences of the ocean surface mixed layer and thermohaline stratification on Arctic Sea ice in the central Canada Basin. J. Geophys. Res

  18. Structure, inferred mechanical properties, and implications for fluid transport in the décollement zone, Costa Rica convergent margin (United States)

    Tobin, Harold; Vannucchi, Paola; Meschede, Martin


    Faults in a variety of tectonic settings can act as both conduits for and barriers to fluid flow, sometimes simultaneously. Documenting the interaction between hydrologic and tectonic processes in active faults in situ is the key to understanding their mechanical behavior and large-scale fluid transport properties. We present observations of the plate boundary décollement zone at the Middle America Trench off Costa Rica, showing that it is structurally divisible into an upper brittle-fracture dominated domain overlying a lower, ductile domain. Pore-water geochemical evidence shows that along-fault flow is occurring specifically in the upper brittle domain, but is hydrologically isolated from fluids in the underlying footwall sediments. We propose a model for the mechanics of these contrasting domains in which differing stress paths coexist in the upper and lower parts of the décollement zone. The data suggest a mechanically controlled permeability anisotropy at a scale of several meters to ˜10 m across the décollement zone. This documentation of separate yet simultaneously active mechanical and hydrologic subregimes within a décollement provides a relatively simple explanation for enhanced along-fault permeability coexisting with reduced cross-fault permeability, without requiring matrix-scale permeability anisotropy.

  19. Mantle enrichment by volatiles as the Nazca plate subducts beneath the Payenia backarc of the Southern Volcanic Zone, Argentina

    DEFF Research Database (Denmark)

    Brandt, Frederik Ejvang

    , minerals, fluid and melt inclusions from the Payenia backarc province of the Andean Southern Volcanic Zone. Major emphasis has been on olivine hosted melt inclusions. The study gives evidence for the role of fluids in the metasomatism of the backarc mantle, and outlines the trend of the variation...... of the metasomatism in Payenia, which is also characterized by a variation in oxidation state and other geochemical parameters of the melt inclusions, and is moreover related to mantle lithological variations. The mantle metasomatism by melts of subducted crust and fluid-borne enrichment is quantitatively modelled......, the origin of Chlorine is explained via slab-derived fluids, and the contrast between backarc and frontal arc magmas is discussed. These results add to the understanding of the origin of the complexities in the mantle wedge under arc-backarc in a subduction zone which has transition to flat slab conditions...

  20. Preliminary Thermo-Chronometric and Paleo-Magnetic Results from the Western Margin of The Kırşehir Block: Implications for the Timing of Continental Collisions Occurred Along Neo-Tethyan Suture Zones (Central Anatolia, Turkey) (United States)

    Gülyüz, Erhan; Özkaptan, Murat; Langereis, Cor G.; Kaymakcı, Nuretdin


    Closures of Paleo- (largely Paleozoic) and Neo-Tethys (largely Mesozoic) Oceans developed between Europe, Africa and Arabia are the main driving mechanisms behind the post-Triassic tectonics, magmatism and metamorphism occurred in Anatolia. Although various scenarios have been suggested for the timing and characteristics of the subduction systems, it is largely accepted that these blocks are progressively collided and amalgamated along the northern (İzmir-Ankara-Erzincan suture zone; IAESZ) and the southern (Bitlis-Zagros suture zone; BZSZ) branches of Neo-Tethys Ocean. The geographic positions of these suture zones in Anatolia are marked by imbricated stacks of largely metamorphosed remnants of the Paleo- and Neo-Tethys Oceans. In addition to this tectonic frame, the existence of another suture zone within the northern branch of the Neo-Tethys separating the Kırşehir Block, a triangular (200km*200km*200km) continental domain represented by mainly high-pressure (HP) meta-sedimentary rocks, from the Taurides, is proposed and named as Intra-Tauride Suture Zone (ITSZ). Although traces of the Neo-Tethyan closure and continental collisions in the Central Anatolia are recorded (1) in sedimentary basins as fold and thrust belt developments (as northern Taurides fold and thrust belt along IAESZ and central Taurides fold and thrust belt along ITSZ), (2) on metamorphic rocks with Late Cretaceous to Late Paleocene peak metamorphism, and (3) on magmatic rocks with Late Cretaceous - Paleocene arc-related intrusions and post-Paleocene post-collisional magmatism, timing of these continental collisions are discussed in limited studies and furthermore they indicate a large time span (post-Paleocene to Miocene) for the collisions. This study aims to date continental collisions occurred in Central Anatolia qualitatively. In this regard, low-temperature thermo-chronometric and paleo-magnetic studies were conducted on the sedimentary units cropped-out along the western and north

  1. Constraints on the thermal evolution of the Adriatic margin during Jurassic continental break-up: U-Pb dating of rutile from the Ivrea-Verbano Zone, Italy (United States)

    Ewing, Tanya A.; Rubatto, Daniela; Beltrando, Marco; Hermann, Jörg


    The Ivrea-Verbano Zone (IVZ), northern Italy, exposes an attenuated section through the Permian lower crust that records high-temperature metamorphism under lower crustal conditions and a protracted history of extension and exhumation associated partly with the Jurassic opening of the Alpine Tethys ocean. This study presents SHRIMP U-Pb geochronology of rutile from seven granulite facies metapelites from the base of the IVZ, collected from locations spanning ~35 km along the strike of Paleozoic fabrics. Rutile crystallised during Permian high-temperature metamorphism and anatexis, yet all samples give Jurassic rutile U-Pb ages that record cooling through 650-550 °C. Rutile age distributions are dominated by a peak at ~160 Ma, with a subordinate peak at ~175 Ma. Both ~160 and ~175 Ma age populations show excellent agreement between samples, indicating that the two distinctive cooling stages they record were synchronous on a regional scale. The ~175 Ma population is interpreted to record cooling in the footwall of rift-related faults and shear zones, for which widespread activity in the Lower Jurassic has been documented along the western margin of the Adriatic plate. The ~160 Ma age population postdates the activity of all known rift-related structures within the Adriatic margin, but coincides with extensive gabbroic magmatism and exhumation of sub-continental mantle to the floor of the Alpine Tethys, west of the Ivrea Zone. We propose that this ~160 Ma early post-rift age population records regional cooling following episodic heating of the distal Adriatic margin, likely related to extreme lithospheric thinning and associated advection of the asthenosphere to shallow levels. The partial preservation of the ~175 Ma age cluster suggests that the post-rift (~160 Ma) heating pulse was of short duration. The regional consistency of the data presented here, which is in contrast to many other thermochronometers in the IVZ, demonstrates the value of the rutile U

  2. Late extensional shear zones and associated recumbent folds in the Alpujarride subduction complex, Betic Cordillera, southern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Orozco, M.; Alonso-Chaves, F.; Platt, J.


    The existence in the Alpujarride Complex (Betic Cordillera, southern Spain) of a relatively continuous extensional event (following crustal thickening) is based on detailed structural studies and is consistent with the P-T paths and geochronological data established for the Alpujarride rocks. According to our research, the Alpujarride Complex contains two large-scale shear zones accommodating early Miocene extension. The shear zones contain km-scale recumbent folds, some with sheath fold geometry, and megaboudinage structures, and are closely associated with detachment faults. Large-scale folds and boudins cause dome-like undulations in the detachments, which are inferred to overlap in time with the deformation in the shear zones. One shear zone in the eastern part of the orogen is top-N; the other, in the western part, is top-E. The change in the shear direction may represent a temporal evolution in the direction of shear, possibly related to a change in the subduction direction in space and time.

  3. Cutaneous manifestations of B-cell chronic lymphocytic leukemia associated with Borrelia burgdorferi infection showing a marginal zone B-cell lymphoma-like infiltrate. (United States)

    Kash, Natalie; Fink-Puches, Regina; Cerroni, Lorenzo


    We report on a 69-year-old female patient with specific cutaneous manifestations of B-cell chronic lymphocytic leukemia that arose at the site of erythema chronicum migrans due to Borrelia burgdorferi infection. Histological examination revealed the presence of dense infiltrates of small hyperchromatic lymphocytes admixed with clusters of plasma cells. Immunohistology showed a CD5+/CD20+ phenotype of the lymphocytes and monoclonal expression of kappa immunoglobulin light chain by the plasma cells. Presence of Borrelia DNA was confirmed by polymerase chain reaction studies. The unusual histopathological and phenotypic findings described in this case of cutaneous manifestations of B-cell chronic lymphocytic leukemia associated with Borrelia burgdorferi infection may lead to the misdiagnosis of cutaneous marginal zone B-cell lymphoma.

  4. Rapidly induced, T-cell independent xenoantibody production is mediated by marginal zone B cells and requires help from NK cells. (United States)

    Li, Shengqiao; Yan, Yehong; Lin, Yuan; Bullens, Dominique M; Rutgeerts, Omer; Goebels, Jozef; Segers, Constant; Boon, Louis; Kasran, Ahmad; De Vos, Rita; Dewolf-Peeters, Christiane; Waer, Mark; Billiau, An D


    Xenoantibody production directed at a wide variety of T lymphocyte-dependent and T lymphocyte-independent xenoantigens remains the major immunologic obstacle for successful xenotransplantation. The B lymphocyte subpopulations and their helper factors, involved in T-cell-independent xenoantibody production are only partially understood, and their identification will contribute to the clinical applicability of xenotransplantation. Here we show, using models involving T-cell-deficient athymic recipient mice, that rapidly induced, T-cell-independent xenoantibody production is mediated by marginal zone B lymphocytes and requires help from natural killer (NK) cells. This collaboration neither required NK-cell-mediated IFN-gamma production, nor NK-cell-mediated cytolytic killing of xenogeneic target cells. The T-cell-independent IgM xenoantibody response could be partially suppressed by CD40L blockade.

  5. Palaeomagnetism of Cretaceous to Tertiary sediments from southern Tibet: evidence for the extent of the northern margin of India prior to the collision with Eurasia (United States)

    Patzelt, A.; Li, Huamei; Wang, Junda; Appel, E.


    Palaeomagnetic studies have been carried out on mid-Cretaceous to latest Palaeocene sediments from the Tethyan Himalaya on the northern margin of the Indian Plate near the localities of Gamba (28.3°N, 88.5°E) and Duela (28.0°N, 89.2°E) in southern Tibet. A total of 61 sites (more than 700 cores) have been sampled mainly from limestones (Zongshan Formation, Jidula Formation Member II, Zongpu Formation), sandstones (Jidula Formation Member III) and graywackes (Gamba Group Member II), with ages well defined from detailed lithological and biostratigraphic analyses. Carriers of characteristic remanences are magnetite in limestones and graywackes, and hematite in sandstones. Reliable palaeodirections were obtained from 35 sites (356 specimens). Positive fold tests, antiparallel normal and reverse polarities, a northward trend of the palaeolatitudes with decreasing age, and absence of any metamorphic overprint indicate a primary origin for the characteristic remanences. The results have been compared with expected palaeodirections according to available data for the Indian subcontinent based on its present-day geometry. The late Maastrichtian sites (fourteen sites, 156 specimens) and the middle-Late Palaeocene sites (fourteen sites, 113 specimens) yield palaeolatitudes of 5.7°S and 4.0°N for the sampling localities in southern Tibet, respectively. These palaeolatitudes are much further north than expected and imply that crustal shortening between the Tethyan Himalaya and the Indian Shield since the time of India-Eurasia collision has occurred on the order of 1500 km at the longitude of Gamba/Duela. Comparison of our observed palaeolatitudes with palaeolatitudes for the Lhasa block during Cretaceous and Palaeocene times indicate that initial contact of the northern Indian margin with the Lhasa block was already established at 65-60 Ma with suturing completed at about 55-50 Ma.

  6. Meso-/Cenozoic long-term landscape evolution at the southern Moroccan passive continental margin, Tarfaya Basin, recorded by low-temperature thermochronology (United States)

    Sehrt, Manuel; Glasmacher, Ulrich A.; Stockli, Daniel F.; Jabour, Haddou; Kluth, Oliver


    This paper presents the first regional study of low-temperature thermochronology to be undertaken in the Tarfaya Basin at the southern Moroccan passive continental margin. The basin is characterised by vast subsidence since Mid-Triassic times, whereby up to 12 km of Meso- to Cenozoic sedimentary rocks accumulated. The study focused on the post-rift vertical movements along a typical ;passive; margin and besides dealt with the timing and maximum temperature reached by potential source rocks of the basin. To unravel the t-T development, thermochronological analyses were performed on 50 outcrop and well samples from Meso-Cenozoic rocks. Thermochronological data reveal a continuous subsidence phase in the offshore basin from Mid-Triassic to recent times. In contrast, apatite (U-Th-Sm)/He and apatite fission-track data as well as thermal modelling point to an inversion of the northeastern onshore basin starting in the Palaeogene at 65-55 Ma. The rock uplift and exhumation period resulted in the erosion of a 1.0-1.4 km thick Cretaceous-Palaeogene sedimentary pile contemporaneously with peak Atlas surface uplift in the Cenozoic. The exhumation stage could be an explanation for the increasing periodic influx of detrital material into the offshore and southern onshore Tarfaya Basin since Palaeocene. Detrital apatite fission-track ages from 92 (± 16) to 237 (± 35) Ma of the Upper Cretaceous-Neogene succession indicate no heating above 60 °C confirming immature to early mature Cenomanian to Campanian and Eocene source rocks in the onshore Tarfaya Basin.

  7. Geophysical evidence for wedging in the San Gorgonio Pass structural knot, southern San Andreas fault zone, southern California (United States)

    Langenheim, V.E.; Jachens, R.C.; Matti, J.C.; Hauksson, E.; Morton, D.M.; Christensen, A.


    Geophysical data and surface geology define intertonguing thrust wedges that form the upper crust in the San Gorgonio Pass region. This picture serves as the basis for inferring past fault movements within the San Andreas system, which are fundamental to understanding the tectonic evolution of the San Gorgonio Pass region. Interpretation of gravity data indicates that sedimentary rocks have been thrust at least 5 km in the central part of San Gorgonio Pass beneath basement rocks of the southeast San Bernardino Mountains. Subtle, long-wavelength magnetic anomalies indicate that a magnetic body extends in the subsurface north of San Gorgonio Pass and south under Peninsular Ranges basement, and has a southern edge that is roughly parallel to, but 5-6 km south of, the surface trace of the Banning fault. This deep magnetic body is composed either of upper-plate rocks of San Gabriel Mountains basement or rocks of San Bernardino Mountains basement or both. We suggest that transpression across the San Gorgonio Pass region drove a wedge of Peninsular Ranges basement and its overlying sedimentary cover northward into the San Bernardino Mountains during the Neogene, offsetting the Banning fault at shallow depth. Average rates of convergence implied by this offset are broadly consistent with estimates of convergence from other geologic and geodetic data. Seismicity suggests a deeper detachment surface beneath the deep magnetic body. This interpretation suggests that the fault mapped at the surface evolved not only in map but also in cross-sectional view. Given the multilayered nature of deformation, it is unlikely that the San Andreas fault will rupture cleanly through the complex structures in San Gorgonio Pass. ?? 2005 Geological Society of America.

  8. Metamorphic history of garnet-rich gneiss at Ktiš in the Lhenice shear zone, Moldanubian Zone of the southern Bohemian Massif, inferred from inclusions and compositional zoning of garnet (United States)

    Kobayashi, Tomoyuki; Hirajima, Takao; Kawakami, Tetsuo; Svojtka, Martin


    Multiple equilibrium stages were identified from garnet-rich gneiss at Ktiš in the Lhenice shear zone of the southern Bohemian Massif, Czech Republic. The matrix of the rock mainly comprises cordierite (Crd), sillimanite (Sil), biotite (Bt), garnet (Grt), quartz (Qtz), K-feldspar (Kfs) and plagioclase (Pl) along with accessory minerals such as spinel (Spl), apatite (Ap), monazite (Mnz) and zircon (Zrn). Bt, Sil, kyanite (Ky) and Pl occur as inclusion phases in Grt. Crd occurs only in the matrix both as isolated grains and as reaction coronas developed around Grt. Spl is closely correlated with the Crd corona. Some coarse-grained (> 3 mm) Grts show chemical heterogeneity both in major and trace elements. Grossular (Grs)-content is homogeneous and high {Xgrs = Ca / (Ca + Mg + Fe + Mn) = 0.27} in a center of the grain and smoothly decreases towards the grain margin (Xgrs = 0.02). However, pyrope (Prp)-content shows an inverse pattern against Grs-content; i.e., Prp-content is low and constant {Xprp = Mg / (Ca + Mg + Fe + Mn) = 0.03} in the center of the grain and gradually increases towards the margin (up to Xprp = 0.28). The contours of Grs- and Prp-contents show symmetrical hexagonal shapes. The distribution pattern of phosphorus, however, shows a striking contrast against Grs-content. The core of the grain is characterized by low-phosphorus content almost below the detection limit of the EPMA analysis but it is armored by the high-phosphorus rim accompanying with local development of phosphorus-poor outermost rim. The outline of phosphorus-poor core shows a hexagonal shape, which is symmetrical to those of Grs- and Prp-content contours, but it is located outside of higher-Grs (Xgrs = 0.27)- and lower-Prp (Xprp = 0.03)-content contours. These observations suggest that the outline of phosphorus-poor core should indicate the original shape of Grs-rich garnet developed during an early stage of the metamorphism. The zoning pattern of major/trace elements in garnet and

  9. Long-term geomorphological evolution of the axial zone of the Campania-Lucania Apennine, southern Italy: a review

    Directory of Open Access Journals (Sweden)

    Schiattarella Marcello


    Full Text Available Uplift and erosion rates have been calculated for a large sector of the Campania-Lucania Apennine and Calabrian arc, Italy, using both geomorphological observations (elevations, ages and arrangement of depositional and erosional land surfaces and other morphotectonic markers and stratigraphical and structural data (sea-level related facies, base levels, fault kinematics, and fault offset estimations. The values of the Quaternary uplift rates of the southern Apennines vary from 0.2 mm/yr to about 1.2–1.3 mm/yr. The erosion rates from key-areas of the southern Apennines, obtained from both quantitative geomorphic analysis and missing volumes calculations, has been estimated at 0.2 mm/yr since the Middle Pleistocene. Since the Late Pleistocene erosion and uplift rates match well, the axial-zone landscape could have reached a flux steady state during that time, although it is more probable that the entire study area may be a transient landscape. Tectonic denudation phenomena — leading to the exhumation of the Mesozoic core of the chain — followed by an impressive regional planation started in the Late Pliocene have to be taken into account for a coherent explanation of the morphological evolution of southern Italy.

  10. Did prolonged two-stage fragmentation of the supercontinent Kenorland lead to arrested orogenesis on the southern margin of the Superior province?

    Directory of Open Access Journals (Sweden)

    Grant M. Young


    Full Text Available Recent geochronological investigations reinforce the early suggestion that the upper part of the Paleoproterozoic Huronian Supergroup of Ontario, Canada is present in the Animikie Basin on the south shore of Lake Superior. These rocks, beginning with the glaciogenic Gowganda Formation, are interpreted as passive margin deposits. The absence of the lower Huronian (rift succession from the Animikie Basin may be explained by attributing the oldest Paleoroterozoic rocks in the Animikie Basin (Chocolay Group to deposition on the upper plate of a north-dipping detachment fault, which lacks sediments of the rift phase. Following thermal uplift that led to opening of the Huronian Ocean on the south side of what is now the Superior province, renewed uplift (plume activity caused large-scale gravitational folding of the Huronian Supergroup accompanied by intrusion of the Nipissing diabase suite and Senneterre dikes at about 2.2 Ga. Termination of passive margin sedimentation is normally followed by ocean closure but in the Huronian and Animikie basins there was a long hiatus -- the Great Stratigraphic Gap -- which lasted for about 350 Ma. This hiatus is attributed to a second prolonged thermal uplift of part of Kenorland that culminated in complete dismemberment of the supercontinent shortly before 2.0 Ga by opening of the Circum-Superior Ocean. These events caused regional uplift (the Great Stratigraphic Gap and delayed completion of the Huronian Wilson Cycle until a regional compressional tectonic episode, including the Penokean orogeny, belatedly flooded the southern margin of the Superior province with foreland basin deposits, established the limits of the Superior structural province and played an important role in constructing Laurentia.

  11. Constraints on the thermal evolution of the Adriatic margin during Jurassic continental break-up from U-Pb dating of rutile (Ivrea-Verbano Zone, Italy) (United States)

    Ewing, T. A.; Rubatto, D.; Hermann, J.; Beltrando, M.


    U­-Pb dating of rutile is an ideal tool for exploring the cooling and exhumation history of the lower crust, given its moderate closure temperature and the occurrence of rutile in relevant lithologies. We present an example from the Ivrea-Verbano Zone (IVZ, Italy), a classic section through the Permian lower crust that records high-temperature metamorphism followed by extension and exhumation associated partly with the Jurassic opening of the Alpine Tethys ocean. Granulite facies metapelites collected across ~35 km have Zr-in-rutile temperatures that record crystallisation during Permian metamorphism and anatexis, but SHRIMP U-Pb dating of rutile records cooling through 650-550 °C in the Jurassic. Rutile age distributions are dominated by a peak at ~160 Ma, with a subordinate peak at ~175 Ma. Both age populations show excellent agreement between samples, indicating that the two distinctive cooling stages they record were synchronous on a regional scale. The ~175 Ma population is interpreted to record cooling in the footwall of rift-related faults and shear zones, for which widespread activity in the Lower Jurassic has been documented along the western margin of the Adriatic plate. The ~160 Ma age population postdates the activity of all known rift-related structures within the Adriatic margin, but coincides with extensive gabbroic magmatism and exhumation of sub-continental mantle to the floor of the Alpine Tethys, west of the IVZ. We propose that this ~160 Ma early post-rift age population records regional cooling following episodic heating of the distal Adriatic margin. The partial preservation of the ~175 Ma age cluster suggests that the post-rift (~160 Ma) heating pulse was of short duration. The regional consistency of the rutile U-Pb data is in contrast to many other thermochronometers in the IVZ, demonstrating the value of this technique for probing the thermal evolution of high-grade metamorphic terranes. The decoupling between Zr-in-rutile temperatures

  12. Soil Moisture/ Tree Water Status Dynamics in a Mid-Latitude Montane Forest, Southern Sierra Critical Zone Observatory, CA (United States)

    Hartsough, P. C.; Malazian, A.; Kamai, T.; Roudneva, E.; Hopmans, J. W.


    In the Mediterranean climate of the Sierra Nevada, snow pack persists well into the spring after precipitation has effectively stopped. With the onset of summer and continued dry conditions, snow quickly melts, and soil profiles dry out as shrubs and trees deplete the available soil moisture. A better understanding of surface and subsurface water budgets in remote landscapes warrants closer monitoring of moisture and temperature variability in near surfaces soils. As part of the Southern Sierra Critical Zone Observatory (CZO), investigators from University of California deployed approximately 150 soil moisture, water potential and temperature sensors within the root structure of an individual white fir tree (Abies concolor) located in the Kings River Experimental Watershed (KREW). These sensors complement sap flow measurements in the trunk, stem water potential measurements in the canopy, and snow depth measurements, to enable the Southern Sierra CZO researchers to investigate how soil environmental stresses (water, temperature, and nutrients) impact forest ecosystems across the rain-to-snow-dominated transition zone. We captured the dynamics of the soil profile desiccation at various depths beneath the snow pack as soils went from wet to very dry conditions. Monitoring of sap flow and periodic leaf water potential measurements, we tracked the activity of the tree as it responded to changing available moisture in the root zone. All sensors were reactive to moisture and temperature variations and showed dynamic responses to precipitation, snow melt and changes in vegetative demand. We demonstrate here the initial phase of a multi-year deployment of soil moisture sensors as a critical integrator of hydrologic/ biotic interaction in a forested catchment as part of a wider effort to document changing ecosystem response to changing environmental inputs.

  13. Formation processes of sea ice floe size distribution in the interior pack and its relationship to the marginal ice zone off East Antarctica (United States)

    Toyota, Takenobu; Kohout, Alison; Fraser, Alexander D.


    To understand the behavior of the Seasonal Ice Zone (SIZ), which is composed of sea-ice floes of various sizes, knowledge of the floe size distribution (FSD) is important. In particular, FSD in the Marginal Ice Zone (MIZ), controlled by wave-ice interaction, plays an important role in determining the retreating rates of sea-ice extent on a global scale because the cumulative perimeter of floes enhances melting. To improve the understanding of wave-ice interaction and subsequent effects on FSD in the MIZ, FSD measurements were conducted off East Antarctica during the second Sea Ice Physics and Ecosystems eXperiment (SIPEX-2) in late winter 2012. Since logistical reasons limited helicopter operations to two interior ice regions, FSD in the interior ice region was determined using a combination of heli-photos and MODIS satellite visible images. The possible effect of wave-ice interaction in the MIZ was examined by comparison with past results obtained in the same MIZ, with our analysis showing: (1) FSD in the interior ice region is basically scale invariant for both small- (1 km) scale regimes; (2) although fractal dimensions are quite different between these two regimes, they are both rather close to that in the MIZ; and (3) for floes pack.

  14. Transport of East Asian dust storms to the marginal seas of China and the southern North Pacific in spring 2010 (United States)

    Tan, Sai-Chun; Li, Jiawei; Che, Huizheng; Chen, Bin; Wang, Hong


    The transport of a super-severe dust storm that occurred in East Asia from 19 to 22 March 2010 has been well documented by both model simulations and surface observations. We investigated the transport of this severe dust storm and several other spring 2010 dust storms using model simulations, backward trajectories, and measurements from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. The model simulations indicated that the emission of dust in spring 2010 was about 35% higher than that in spring 2006 and was twice that of the 44-year average from 1960 to 2003. The dust emissions over two major source regions (western China and the Gobi Desert) in spring 2010 accounted for 86% of the total amount of dust. The simulated depositional flux over the two major source regions was c.2.7-9.0 times that over two marginal seas (the Yellow Sea and the East China Sea) and more than two magnitudes higher than that over the North Pacific Subtropical Gyre. The mean extinction coefficient observed by the CALIPSO satellite over the two source regions was c.1.3-3.7 times that over the two marginal seas and one magnitude higher than that over the North Pacific. This was consistent with the result from our model, suggesting that this model is able to capture the major features of dust storms. The vertical profiles recorded by the CALIPSO satellite indicated that the dust aerosol mainly floated from the ground to 13 km above ground level over the source regions and above the seas. A multiple dust layer appeared over the seas and the backward trajectories suggested that the dust aerosol in different layers may have been sourced from different regions.

  15. Does water level affect benthic macro-invertebrates of a marginal lake in a tropical river-reservoir transition zone? (United States)

    Zerlin, R A; Henry, R


    Benthic macro-invertebrates are important components of freshwater ecosystems which are involved in ecological processes such as energy transfer between detritus and consumers and organic matter recycling. The aim of this work was to investigate the variation in organism richness, diversity and density of benthic fauna during the annual cycle in Camargo Lake, a lake marginal to Paranapanema River, southeast Brazil. The correlation of environmental factors with community attributes of the macro-benthic fauna was assessed. Since Camargo Lake is connected to the river, we tested the hypothesis that water level variation is the main regulating factor of environmental variables and of the composition and abundance of benthic macro-invertebrates. The results indicated that lake depth varied with rainfall, being the highest at the end of the rising water period and the lowest at the beginning of this period. The sediment granulometry was more heterogeneous at the bottom of the lake by the end of the high water period. The benthic macro-invertebrate fauna was composed by 15 taxa. The Diptera order was represented by seven taxa and had greater richness in relation to other taxa. This group was responsible for 60% of the total abundance of organisms, followed by Ephemeroptera (22%) and Anellida (16%). Significant differences were observed over time in total richness and, in density of Narapa bonettoi, Chaoborus, Ablabesmyia gr. annulata, Chironomus gigas, Larsia fittkau, and Procladius sp. 2. Total taxa richness correlated negatively with water pH, transparency, conductivity, and bottom water oxygen. Higher positive correlations were found between the densities of some taxa and bottom water oxygen, conductivity and very fine sand, silt + clay of sediment, while negative correlations were recorded with organic matter, and fine, medium and coarse sand, bottom water temperature, mean temperature and rainfall. The significant temporal difference in water level was associated

  16. Miocene burial and exhumation of the India-Asia collision zone in southern Tibet: response to slab dynamics and erosion (United States)

    Carrapa, Barbara; Orme, D.A.; DeCelles, Peter G.; Kapp, Paul; Cosca, Michael A.; Waldrip, R.


    The India-Asia collision zone in southern Tibet preserves a record of geodynamic and erosional processes following intercontinental collision. Apatite fission-track and zircon and apatite (U-Th)/He data from the Oligocene–Miocene Kailas Formation, within the India-Asia collision zone, show a synchronous cooling signal at 17 ± 1 Ma, which is younger than the ca. 26–21 Ma depositional age of the Kailas Formation, constrained by U-Pb and 40Ar/39Ar geochronology, and requires heating (burial) after ca. 21 Ma and subsequent rapid exhumation. Data from the Gangdese batholith underlying the Kailas Formation also indicate Miocene exhumation. The thermal history of the Kailas Formation is consistent with rapid subsidence during a short-lived phase of early Miocene extension followed by uplift and exhumation driven by rollback and northward underthrusting of the Indian plate, respectively. Significant removal of material from the India-Asia collision zone was likely facilitated by efficient incision of the paleo–Indus River and paleo–Yarlung River in response to drainage reorganization and/or intensification of the Asian monsoon.

  17. Variations of mesoscale and large-scale sea ice morphology in the 1984 Marginal Ice Zone Experiment as observed by microwave remote sensing (United States)

    Campbell, W. J.; Gloersen, P.; Josberger, E. G.; Johannessen, O. M.; Guest, P. S.; Mognard, N.; Shuchman, R.; Burns, B. A.; Lannelongue, N.; Davidson, K. L.


    During the summer 1984 Marginal Ice Zone Experiment in the Fram Strait and Greenland Sea (MIZEX '84), passive and active microwave sensors on five aircraft and the Nimbus 7 scanning multichannel microwave radiometer (SMMR) acquired synoptic sequential observations which when combined give a comprehensive sequential description of the mesoscale and large-scale ice morphology variations during the period June 9 through July 16, 1984. The high-resolution ice concentration distributions in these images agree well with the low-resolution SMMR distributions. For diffuse ice edges the 30% SMMR ice concentration isopleth corresponds to the ice edge, while for compact conditions the ice edge falls within the 40 to 50% SMMR isopleths. Throughout the experiment, ice edge meanders and eddies repeatedly formed, moved, and disappeared, but the ice edge remained within a 100-km-wide zone. The ice pack behind this alternately diffuse and compact edge underwent rapid and pronounced variations in ice concentration over a 200-km-wide zone. The aircraft microwave images show the complex structures and ephemeral nature of the mesoscale sea ice morphology. The difference in oceanographic forcing between the eastern and western sectors of the experiment area generated pronounced ice morphology differences. On the Yermak Plateau, from 3°E to 10°E, the weak ocean circulation allowed the wind to be the dominant force in determining the ice morphology. To the southwest of this region, over the Molloy Deep and the Greenland continental shelf break, from 3°E to 8°W, the ice morphology was dominated by the energetic East Greenland Current with its associated eddies and meanders.

  18. Structural and functional study of the nematode community from the Indian western continental margin with reference to habitat heterogeneity and oxygen minimum zone (United States)

    Singh, R.; Ingole, B. S.


    We studied patterns of nematode distribution along the western Indian continental margin to determine the influence of habitat heterogeneity and oxygen minimum on the community's taxonomic and functional structure. A single transect, perpendicular to the coast at 14° N latitude was sampled from 34 to 2546 m depth for biological and environmental variables during August 2007. Nematodes were identified to species and classified according to biological/functional traits. A total of 110 nematode species belonging to 24 families were found along the transect. Mean nematode density was higher on the shelf (176 ind 10 cm-2, 34 m depth) than on the slope (124 ind 10 cm-2) or in the basin 62.9 ind 10 cm-2). Across the entire study area, the dominant species were Terschellingia longicaudata, (15.2 %), Desmodora sp 1, Sphaerolaimus gracilis, and Theristus ensifer; their maximum density was at shelf stations. Multidimensional scaling ordination (nMDS) of the nematode species abundance data indicated the effect of different zones (ANOSIM; Global R = 0.607; P = 0.028), but it was not the same in case of functional traits. Only seven species were found exclusively in the oxygen minimum zone: Pselionema sp 1, Choanolaimus sp 2, Halichoanolaimus sp 1, Cobbia dentata, Daptonema sp 1, Trissonchulus sp 1, and Minolaimus sp 1. Moreover, in our study, species diversity was higher on the shelf than on the slope or in the basin. The distinctive features of all three zones as based on nematofaunal abundance were also reflected in the functional traits (feeding types, body shape, tail shape, and life history strategy). Correlation with a number of environmental variables indicated that food quality (measured as the organic carbon content and chlorophyll content) and oxygen level were the major factors that influenced the nematode community (structural and functional).

  19. A relict triangle zone at Benjamin Creek gas field, southern Alberta Foothills: geometry, kinematics and preservation

    Energy Technology Data Exchange (ETDEWEB)

    Dechesne, R. G.; Muraro, J. W.


    A triangle zone with an internal duplex in the Williams Creek Syncline in the footwall of the Burnt Timber Thrust in the Alberta Foothills was studied and characterized as a relict intercutaneous wedge. This interpretation was based on the presence of a roof thrust that does not wrap over the duplex, the apparent absence of shortening transferred through the triangle zone towards the foreland, and the younger structures below and east of the triangle zone. Three possible histories, based on the presence and amount of out-of-sequence motion on the Burnt Timber Thrust, were advanced to explain the kinematic relationship of the intercutaneous wedge with the Burnt Timber Thrust. 36 refs., 8 figs.

  20. Factors affecting women’s intention to use long acting and permanent contraceptive methods in Wolaita Zone, Southern Ethiopia: A cross-sectional study


    Meskele,Mengistu; Mekonnen, Wubegzier


    Background The use of long acting and permanent contraceptive methods (LAPMs) has not kept step with that of short-acting methods such as oral pills and injectable in Africa. This study explores the association between women’s awareness, attitude and barriers with their intention to use LAPMs among users of short term methods, in Southern Ethiopia. Methods A cross-sectional study design of mixed methods was conducted in the public health facilities of Wolaita zone, Southern Ethiopia, in Janua...

  1. First evidence of lamprophyric magmatism within the Subbetic Zone (Southern Spain)

    NARCIS (Netherlands)

    Puga, E.; Beccaluva, L.; Bianchini, G.; De Federico, A.D.; Puga, M.A.D.; Alvarez-Valero, A.M.; Galindo-Zaldivar, J.; Wijbrans, J.R.


    Two drillings carried out at Cerro Prieto (Province of Málaga), together with additional geophysical data, revealed the existence of an igneous body formed of rock-types previously unknown in the Subbetic zone. The recovered rocks, emplaced under hypoabyssal conditions, are predominantly porphyric,

  2. Spatial and temporal distribution of contaminated, effluent-affected sediment on the Palos Verdes margin, southern California (United States)

    Lee, Homa J.; Sherwood, Christopher R.; Drake, David E.; Edwards, Brian D.; Wong, Florence; Hamer, Michael


    A sedimentary deposit on the continental margin near the Palos Verdes Peninsula, California is comprised of sewage effluent and geologic materials and is contaminated with metals, pesticides (including DDT and associated compounds), and PCBs. The deposit was mapped with subbottom acoustic profilers, and sediment cores were analyzed for geochemical and physical properties to determine the volume of the deposit and the distribution and mass of contaminants. Mapping showed that the deposit ranges up to 60-cm thick, has a total volume exceeding 9 million m 3, and covers over 40 km 2. Virtually the entire effluent-affected deposit is contaminated with DDT and PCBs. Nearly half of the area of the deposit lies on the continental slope, but 70-75% of the volume of the deposit and total mass of DDT reside on the continental shelf. Analysis of data collected biennially since 1981 by the Sanitation Districts of Los Angeles County show that the mass of DDT has apparently decreased at some stations but has remained essentially constant at others. Temporal changes in mass per unit area of DDT are not statistically significant (at the 90% confidence level) at the most contaminated locations over a 16-yr period. The results of this mapping effort were used as a basis for modeling efforts described elsewhere in this issue.

  3. Large-scale hydraulic structure of a seismogenic fault at 10 km depth (Gole Larghe Fault Zone, Italian Southern Alps) (United States)

    Bistacchi, Andrea; Di Toro, Giulio; Smith, Steve; Mittempergher, Silvia; Garofalo, Paolo


    The definition of hydraulic properties of fault zones is a major issue in structural geology, seismology, and in several applications (hydrocarbons, hydrogeology, CO2 sequestration, etc.). The permeability of fault rocks can be measured in laboratory experiments, but its upscaling to large-scale structures is not straightforward. For instance, typical permeability of fine-grained fault rock samples is in the 10-18-10-20 m2 range, but, according to seismological estimates, the large-scale permeability of active fault zones can be as high as 10-10 m2. Solving this issue is difficult because in-situ measurements of large-scale permeability have been carried out just at relatively shallow depths - mainly in oil wells and exceptionally in active tectonic settings (e.g. SAFOD at 3 km), whilst deeper experiments have been performed only in the stable continental crust (e.g. KTB at 9 km). In this study, we apply discrete fracture-network (DFN) modelling techniques developed for shallow aquifers (mainly in nuclear waste storage projects like Yucca Mountain) and in the oil industry, in order to model the hydraulic structure of the Gole Larghe Fault Zone (GLFZ, Italian Southern Alps). This fault, now exposed in world-class glacier-polished outcrops, has been exhumed from ca. 8 km, where it was characterized by a well-documented seismic activity, but also by hydrous fluid flow evidenced by alteration halos and precipitation of hydrothermal minerals in veins and along cataclasites. The GLFZ does not show a classical seal structure that in other fault zones corresponds to a core zone characterized by fine-grained fault rocks. However, permeability is heterogeneous and the permeability tensor is strongly anisotropic due to fracture preferential orientation. We will show with numerical experiments that this hydraulic structure results in a channelized fluid flow (which is consistent with the observed hydrothermal alteration pattern). This results in a counterintuitive situation

  4. Symbiodinium (Dinophyceae) community patterns in invertebrate hosts from inshore marginal reefs of the southern Great Barrier Reef, Australia. (United States)

    Tonk, Linda; Sampayo, Eugenia M; Chai, Aaron; Schrameyer, Verena; Hoegh-Guldberg, Ove


    The broad range in physiological variation displayed by Symbiodinium spp. has proven imperative during periods of environmental change and contribute to the survival of their coral host. Characterizing how host and Symbiodinium community assemblages differ across environmentally distinct habitats provides useful information to predict how corals will respond to major environmental change. Despite the extensive characterizations of Symbiodinium diversity found amongst reef cnidarians on the Great Barrier Reef (GBR) substantial biogeographic gaps exist, especially across inshore habitats. Here, we investigate Symbiodinium community patterns in invertebrates from inshore and mid-shelf reefs on the southern GBR, Australia. Dominant Symbiodinium types were characterized using denaturing gradient gel electrophoresis fingerprinting and sequencing of the ITS2 region of the ribosomal DNA. Twenty one genetically distinct Symbiodinium types including four novel types were identified from 321 reef-invertebrate samples comprising three sub-generic clades (A, C, and D). A range of host genera harbored C22a, which is normally rare or absent from inshore or low latitude reefs in the GBR. Multivariate analysis showed that host identity and sea surface temperature best explained the variation in symbiont communities across sites. Patterns of changes in Symbiodinium community assemblage over small geographic distances (100s of kilometers or less) indicate the likelihood that shifts in Symbiodinium distributions and associated host populations, may occur in response to future climate change impacting the GBR. © 2017 Phycological Society of America.

  5. Palaeoenvironmental and geochemical approach of Archaeocyath-rich facies from Lower Cambrian of Western Gondwana margin at Central Iberian Zone (Urda, Toledo Mountains, Spain) (United States)

    Menéndez, Silvia; Rodríguez-Martínez, Marta; Moreno-Eris, Elena; Perejón, Antonio; Reitner, Joachim


    Archaeocyath-rich facies are located in a quarry close to Urda village, at Toledo Mountains, Spain. The outcrops belong to the Caliza de los Navalucillos Formation and they record a considerably high diverse archaeocyath assemblage in the Lower Cambrian successions from the Central Iberian Zone (Julivert et al. 1972 [1974]). In fact, it is first time recorded the presence of Agyrekocyathus, Dokidocyathus, and Plicocyathus in the Central Iberian Zone. Therefore Plicocyathus is no longer exclusive to biozone VI in Spain. The presence of Anthomorpha is characteristic for the early Botomian, presently early Stage 4 (ICS, 2009), and the assemblage corresponds to the biozone VII (late Ovetian, following the biozonation of Perejón & Moreno-Eiris, 2006). The fossiliferous part of the succession is formed by seven lithofacies, all of them tectonically folded and with a low grade metamorphic overprint. They are comprised by two main groups of facies: (a) mound-shaped to massive lithofacies (A1, A2, A3, A4) and (b) massive to bedded and nodular lithofacies (B1, B2, B3). Archaeocyaths occur in several facies: (A1) mound-shaped white marble with irregular to stromatactoid cavities; (A2) massive mottled white to grey limestone; (A3) massive grey limestone with slumps levels; (A4) massive archaeocyath-rich orange limestone; as well as in carbonate nodules embedded in siltstones and cherts (B1, B2 and B3). The best preserved assemblage comes from the nodule record, where fossils are partially pyritized. This type of preservation is exceptional and has never been described before. XRD and wavelength-dispersive electron microprobe analyses reveal the presence of pyrite and pyrrotine partially altered to iron oxides and hydroxides (hematite and goethite) surrounding the archaeocyath cups. In Central Iberian Zone, the development of mounds and nodular facies like those described here is unusual, although the Botomian marks the peak for Early Cambrian archaeocyathan-microbial mounds

  6. Strong depth-related zonation of megabenthos on a rocky continental margin (∼700-4000 m) off southern Tasmania, Australia. (United States)

    Thresher, Ronald; Althaus, Franziska; Adkins, Jess; Gowlett-Holmes, Karen; Alderslade, Phil; Dowdney, Jo; Cho, Walter; Gagnon, Alex; Staples, David; McEnnulty, Felicity; Williams, Alan


    Assemblages of megabenthos are structured in seven depth-related zones between ∼700 and 4000 m on the rocky and topographically complex continental margin south of Tasmania, southeastern Australia. These patterns emerge from analysis of imagery and specimen collections taken from a suite of surveys using photographic and in situ sampling by epibenthic sleds, towed video cameras, an autonomous underwater vehicle and a remotely operated vehicle (ROV). Seamount peaks in shallow zones had relatively low biomass and low diversity assemblages, which may be in part natural and in part due to effects of bottom trawl fishing. Species richness was highest at intermediate depths (1000-1300 m) as a result of an extensive coral reef community based on the bioherm-forming scleractinian Solenosmilia variabilis. However, megabenthos abundance peaked in a deeper, low diversity assemblage at 2000-2500 m. The S. variabilis reef and the deep biomass zone were separated by an extensive dead, sub-fossil S. variabilis reef and a relatively low biomass stratum on volcanic rock roughly coincident with the oxygen minimum layer. Below 2400 m, megabenthos was increasingly sparse, though punctuated by occasional small pockets of relatively high diversity and biomass. Nonetheless, megabenthic organisms were observed in the vast majority of photographs on all seabed habitats and to the maximum depths observed--a sandy plain below 3950 m. Taxonomic studies in progress suggest that the observed depth zonation is based in part on changing species mixes with depth, but also an underlying commonality to much of the seamount and rocky substrate biota across all depths. Although the mechanisms supporting the extraordinarily high biomass in 2000-2500 m depths remains obscure, plausible explanations include equatorwards lateral transport of polar production and/or a response to depth-stratified oxygen availability.

  7. Strong Depth-Related Zonation of Megabenthos on a Rocky Continental Margin (∼700–4000 m) off Southern Tasmania, Australia (United States)

    Thresher, Ronald; Althaus, Franziska; Adkins, Jess; Gowlett-Holmes, Karen; Alderslade, Phil; Dowdney, Jo; Cho, Walter; Gagnon, Alex; Staples, David; McEnnulty, Felicity; Williams, Alan


    Assemblages of megabenthos are structured in seven depth-related zones between ∼700 and 4000 m on the rocky and topographically complex continental margin south of Tasmania, southeastern Australia. These patterns emerge from analysis of imagery and specimen collections taken from a suite of surveys using photographic and in situ sampling by epibenthic sleds, towed video cameras, an autonomous underwater vehicle and a remotely operated vehicle (ROV). Seamount peaks in shallow zones had relatively low biomass and low diversity assemblages, which may be in part natural and in part due to effects of bottom trawl fishing. Species richness was highest at intermediate depths (1000–1300 m) as a result of an extensive coral reef community based on the bioherm-forming scleractinian Solenosmilia variabilis. However, megabenthos abundance peaked in a deeper, low diversity assemblage at 2000–2500 m. The S. variabilis reef and the deep biomass zone were separated by an extensive dead, sub-fossil S. variabilis reef and a relatively low biomass stratum on volcanic rock roughly coincident with the oxygen minimum layer. Below 2400 m, megabenthos was increasingly sparse, though punctuated by occasional small pockets of relatively high diversity and biomass. Nonetheless, megabenthic organisms were observed in the vast majority of photographs on all seabed habitats and to the maximum depths observed - a sandy plain below 3950 m. Taxonomic studies in progress suggest that the observed depth zonation is based in part on changing species mixes with depth, but also an underlying commonality to much of the seamount and rocky substrate biota across all depths. Although the mechanisms supporting the extraordinarily high biomass in 2000–2500 m depths remains obscure, plausible explanations include equatorwards lateral transport of polar production and/or a response to depth-stratified oxygen availability. PMID:24465758

  8. Strong depth-related zonation of megabenthos on a rocky continental margin (∼700-4000 m off southern Tasmania, Australia.

    Directory of Open Access Journals (Sweden)

    Ronald Thresher

    Full Text Available Assemblages of megabenthos are structured in seven depth-related zones between ∼700 and 4000 m on the rocky and topographically complex continental margin south of Tasmania, southeastern Australia. These patterns emerge from analysis of imagery and specimen collections taken from a suite of surveys using photographic and in situ sampling by epibenthic sleds, towed video cameras, an autonomous underwater vehicle and a remotely operated vehicle (ROV. Seamount peaks in shallow zones had relatively low biomass and low diversity assemblages, which may be in part natural and in part due to effects of bottom trawl fishing. Species richness was highest at intermediate depths (1000-1300 m as a result of an extensive coral reef community based on the bioherm-forming scleractinian Solenosmilia variabilis. However, megabenthos abundance peaked in a deeper, low diversity assemblage at 2000-2500 m. The S. variabilis reef and the deep biomass zone were separated by an extensive dead, sub-fossil S. variabilis reef and a relatively low biomass stratum on volcanic rock roughly coincident with the oxygen minimum layer. Below 2400 m, megabenthos was increasingly sparse, though punctuated by occasional small pockets of relatively high diversity and biomass. Nonetheless, megabenthic organisms were observed in the vast majority of photographs on all seabed habitats and to the maximum depths observed--a sandy plain below 3950 m. Taxonomic studies in progress suggest that the observed depth zonation is based in part on changing species mixes with depth, but also an underlying commonality to much of the seamount and rocky substrate biota across all depths. Although the mechanisms supporting the extraordinarily high biomass in 2000-2500 m depths remains obscure, plausible explanations include equatorwards lateral transport of polar production and/or a response to depth-stratified oxygen availability.

  9. Sub-crustal earthquakes within the Australia-Pacific plate boundary zone beneath the Southern Alps, New Zealand (United States)

    Boese, C. M.; Stern, T. A.; Townend, J.; Bourguignon, S.; Sheehan, A.; Smith, E. G. C.


    Sub-crustal earthquakes have been observed sporadically for ∼40 years in the central South Island of New Zealand. We report on 20 events recorded between December 2008 and February 2012 near the Alpine Fault in the continental collision zone between the Australian and Pacific plates. A subset of 18 events at depths of 47-74 km occurs south of Mt. Cook and together with recently reported tremor locations indicates along-strike variations in deformation behaviour along the plate boundary. The sub-crustal earthquakes south of Mt. Cook increase in depth, frequency and size southwards towards the Puysegur subduction zone. Focal mechanisms could be determined for 14 earthquakes and exhibit predominantly strike-slip and reverse faulting solutions. Stress inversion analysis of the focal mechanisms yields a stress field favouring oblique-reverse faulting. We interpret the geographic and vertical distributions of these sub-crustal events in relation to a previously proposed tectonic model of a remnant passive margin that formed south of New Zealand in the Eocene and was overridden when dextral strike-slip motion initiated on the Alpine Fault. We infer that sub-crustal earthquakes occur along the leading edge of this structure, which is attached to the continental Australian crust.

  10. A Case of Contiguous Primary Hepatic Marginal Zone B-Cell Lymphoma and Hemangioma Ultimately Diagnosed Using Contrast-Enhanced Ultrasonography

    Directory of Open Access Journals (Sweden)

    Kazue Shiozawa


    Full Text Available Primary hepatic marginal zone B-cell malignant lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma is extremely rare. We present a case in which a lesion was diagnosed as 2 contiguous tumors (MALT lymphoma and hemangioma using contrast-enhanced ultrasonography (US with sonazoid. There has been no previous case of contiguous hepatic MALT lymphoma and hemangioma. The present case was a female with no medical history. We detected a snowman-like appearance, which was a tumor of 15 mm in diameter with hypo- and hyper-echogenicities in the lateral and medial parts, respectively, in the Couinaud's segment (S6 of the liver on US. The tumor appeared as a single lesion with a low-density area in the unenhanced phase and prolonged enhancement in the equilibrium phases on dynamic CT. On MRI, the whole lesion showed a low-intensity signal on T1-weighted imaging, but isointensity in the lateral part and high intensity in the medial part were seen on T2-weighted imaging. On contrast-enhanced US, the lateral hypoechoic region was homogenously hyperenhanced in the early vascular phase, and the contrast medium was washed out after about 30 s; in contrast, the medial hyperechoic region was gradually stained from the margin toward the central region. The tumor showed a defect in both hypo- and hyperechoic regions in the postvascular phase. Hemangioma was suspected for the medial part based on the typical image findings, but the lateral part was not given a diagnosis. Thus, surgical resection was performed. The medial part was a hemangioma, and the lateral part was a MALT lymphoma by histopathological findings.

  11. Distribution of TEP in the euphotic and upper mesopelagic zones of the southern Iberian coasts (United States)

    Prieto, L.; Navarro, G.; Cózar, A.; Echevarría, F.; García, C. M.


    The spatial and temporal distributions of transparent exopolymer particles (TEP) were studied for the Gulf of Cádiz, by analyzing its abundance in the euphotic and upper mesopelagic zones. Both layers of the water column should reflect a distinct pattern in TEP distribution, as production of TEP is mainly linked to phytoplankton activity, which is sited in the euphotic zone, while losses of TEP due to aggregation-sinking and degradation occur from the surface to further below in the water column. Concentration of TEP in the euphotic zone reflected the varied oceanographic characteristics of the studied region. It was higher in coastal upwellings, fronts and such areas of topographic forcing, suggesting that TEP were being produced by active growing phytoplankters. A comparison with a well-known ecosystem, the coastal upwelling in the northwestern Alboran Sea, showed that the TEP:Chl a ratio at stations with clear eutrophic characteristics was several orders of magnitude lower than in the area southwest of the anticyclonic current of the Gulf. This ratio in the highly dynamic system of the Strait of Gibraltar seems to have a much clearer relation with the stage of a bloom and, at a basin scale, to the trophic condition of the ecosystem than TEP concentrations alone. Throughout the area studied in the Gulf of Cádiz, the role of TEP for aggregation processes was analyzed based on two aggregation models. Both approximations pointed to the importance of TEP in the export of matter from the euphotic zone to deeper waters in the Gulf of Cádiz.

  12. Marginal zone lymphoma-derived interfollicular diffuse large B-cell lymphoma harboring 20q12 chromosomal deletion and missense mutation of BIRC3 gene: a case report. (United States)

    Hatem, Joseph; Schrank-Hacker, April M; Watt, Christopher D; Morrissette, Jennifer J D; Rubin, Adam I; Kim, Ellen J; Nasta, Sunita D; Wasik, Mariusz A; Bogusz, Agata M


    Diffuse large B-cell lymphoma (DLBCL) typically leads to effacement of the nodal architecture by an infiltrate of malignant cells. Rarely (DLBCL can present with an interfollicular pattern (DLBCL-IF) preserving the lymphoid follicles. It has been postulated that DLBCL-IF is derived from marginal zone B cells and may represent a large-cell transformation of marginal zone lymphoma (MZL), however no direct evidence has been provided to date. Here we describe a rare case of a diagnostically challenging DLBCL-IF involving a lymph node in a patient with a prior history of lymphadenopathy for several years and MZL involving skin. A 53-year old man presented to our Dermatology Clinic due to a 1-year history of generalized itching, fatigue of 2-3 month's duration, nausea and mid back rash that was biopsied. PET (positron emission tomography)/CT (computed tomography) was performed and revealed inguinal, pelvic, retroperitoneal, axillary, and cervical lymphadenopathy. The patient was referred to surgery for excisional biopsy of a right inguinal lymph node. Diagnostic H&E stained slides and ancillary studies were reviewed for the lymph node and skin specimens. B-cell clonality by PCR and sequencing studies were performed on both specimens. We demonstrate that this patient's MZL and DLBCL-IF are clonally related, strongly suggesting that transformation of MZL to DLBCL had occurred. Furthermore, we identified a novel deletion of the long arm of chromosome 20 (del(20q12)) and a missense mutation in BIRC3 (Baculoviral IAP repeat-containing protein 3) in this patient's DLBCL that are absent from his MZL, suggesting that these genetic alterations contributed to the large cell transformation. To our knowledge, this is the first report providing molecular evidence for a previously suspected link between MZL and DLBCL-IF. In addition, we describe for the first time del(20q12) and a missense mutation in BIRC3 in DLBCL. Our findings also raise awareness of DLBCL-IF and discuss the

  13. Recovery of secular deformation field of Mojave Shear Zone in Southern California from historical terrestrial and GPS measurements (United States)

    Liu, Shaozhuo; Shen, Zheng-Kang; Bürgmann, Roland


    The 1992 Mw 7.3 Landers and 1999 Mw 7.1 Hector Mine earthquakes struck the Eastern California Shear Zone (ECSZ) in the Mojave Desert, Southern California. Coseismic and postseismic deformation from these events affect efforts to use Global Positioning System (GPS) observations collected since these events to establish a secular surface velocity field, especially in the near field of the coseismic ruptures. We devise block motion models constrained by both historical pre-Landers triangulation and trilateration observations and post-Landers GPS measurements to recover the secular deformation field and differentiate the postseismic transients in the Mojave region. Postseismic transients are found to remain in the Southern California Earthquake Center Crustal Motion Map Version 4, Plate Boundary Observatory, and Scripps Orbit and Permanent Array Center GPS velocity solutions in the form of 2-3 mm/yr excess right-lateral shear across the Landers and Hector Mine coseismic ruptures. The cumulative deformation rate across the Mojave ECSZ is 13.2-14.4 mm/yr, at least twice the geologic rate since the late Pleistocene (≤6.2 ± 1.9 mm/yr). Postseismic GPS time series based on our secular velocity field reveal enduring late-stage transient motions in the near field of the coseismic ruptures that provide new constraints on the rheological structure of the lower crust and upper mantle.

  14. Predictive zoning of rice stem borer damage in southern India through spatial interpolation of weather-based models. (United States)

    Reji, G; Chander, Subhash; Kamble, Kalpana


    Rice stem borer is an important insect pest causing severe damage to rice crop in India. The relationship between weather parameters such as maximum (T(max)) and minimum temperature (T(min)), morning (RH1) and afternoon relative humidity (RH2) and the severity of stem borer damage (SB) were studied. Multiple linear regression analysis was used for formulating pest-weather models at three sites in southern India namely, Warangal, Coimbatore and Pattambi as SB = -66.849 + 2.102 T(max) + 0.095 RH1, SB = 156.518 - 3.509 T(min) - 0.785 RH1 and SB = 43.483 - 0.418 T(min) - 0.283 RH1 respectively. The pest damage predicted using the model at three sites did not significantly differ from the observed damage (t = 0.442; p > 0.05). The range of weather parameters favourable for stem borer damage at each site were also predicted using the models. Geospatial interpolation (kriging) of the pest-weather models were carried out to predict the zones of stem borer damage in southern India. Maps showing areas with high, medium and low risk of stem borer damage were prepared using geographical information system. The risk maps of rice stem borer would be useful in devising management strategies for the pest in the region.

  15. A shifting rift—Geophysical insights into the evolution of Rio Grande rift margins and the Embudo transfer zone near Taos, New Mexico (United States)

    Grauch, V.J.S.; Bauer, Paul W.; Drenth, Benjamin J.; Kelson, Keith I.


    We present a detailed example of how a subbasin develops adjacent to a transfer zone in the Rio Grande rift. The Embudo transfer zone in the Rio Grande rift is considered one of the classic examples and has been used as the inspiration for several theoretical models. Despite this attention, the history of its development into a major rift structure is poorly known along its northern extent near Taos, New Mexico. Geologic evidence for all but its young rift history is concealed under Quaternary cover. We focus on understanding the pre-Quaternary evidence that is in the subsurface by integrating diverse pieces of geologic and geophysical information. As a result, we present a substantively new understanding of the tectonic configuration and evolution of the northern extent of the Embudo fault and its adjacent subbasin.We integrate geophysical, borehole, and geologic information to interpret the subsurface configuration of the rift margins formed by the Embudo and Sangre de Cristo faults and the geometry of the subbasin within the Taos embayment. Key features interpreted include (1) an imperfect D-shaped subbasin that slopes to the east and southeast, with the deepest point ∼2 km below the valley floor located northwest of Taos at ∼36° 26′N latitude and 105° 37′W longitude; (2) a concealed Embudo fault system that extends as much as 7 km wider than is mapped at the surface, wherein fault strands disrupt or truncate flows of Pliocene Servilleta Basalt and step down into the subbasin with a minimum of 1.8 km of vertical displacement; and (3) a similar, wider than expected (5–7 km) zone of stepped, west-down normal faults associated with the Sangre de Cristo range front fault.From the geophysical interpretations and subsurface models, we infer relations between faulting and flows of Pliocene Servilleta Basalt and older, buried basaltic rocks that, combined with geologic mapping, suggest a revised rift history involving shifts in the locus of fault activity as

  16. Regional Climate Zone Modeling of a Commercial Absorption Heat Pump Hot Water Heater Part 1: Southern and South Central Climate Zones

    Energy Technology Data Exchange (ETDEWEB)

    Geoghegan, Patrick J [ORNL; Shen, Bo [ORNL; Keinath, Christopher M. [Stone Mountain Technologies, Inc., Johnson City; Garrabrant, Michael A. [Stone Mountain Technologies, Inc., Johnson City


    Commercial hot water heating accounts for approximately 0.78 Quads of primary energy use with 0.44 Quads of this amount from natural gas fired heaters. An ammonia-water based commercial absorption system, if fully deployed, could achieve a high level of savings, much higher than would be possible by conversion to the high efficiency nonheat-pump gas fired alternatives. In comparison with air source electric heat pumps, the absorption system is able to maintain higher coefficients of performance in colder climates. The ammonia-water system also has the advantage of zero Ozone Depletion Potential and low Global Warming Potential. A thermodynamic model of a single effect ammonia-water absorption system for commercial space and water heating was developed, and its performance was investigated for a range of ambient and return water temperatures. This allowed for the development of a performance map which was then used in a building energy modeling software. Modeling of two commercial water heating systems was performed; one using an absorption heat pump and another using a condensing gas storage system. The energy and financial savings were investigated for a range of locations and climate zones in the southern and south central United States. A follow up paper will analyze northern and north/central regions. Results showed that the system using an absorption heat pump offers significant savings.

  17. Geochronological and geochemical constraints on the petrogenesis of the early Paleoproterozoic potassic granite in the Lushan area, southern margin of the North China Craton (United States)

    Zhou, Yanyan; Zhai, Mingguo; Zhao, Taiping; Lan, Zhongwu; Sun, Qianying


    We conducted a geochronological and geochemical study on the Paleoproterozoic potassic granites in the Lushan area, southern margin of the North China Craton (NCC) to understand the tectonic regime of the NCC at 2.2-2.1 Ga. This rock suite formed at 2194 ± 29 Ma. The rocks are rich in SiO2 (76.10-77.73 wt.%), and K2O (5.94-6.90 wt.%) with high K2O + Na2O contents from 7.56 wt.% to 8.48 wt.%, but poor in CaO (0.10-0.28 wt.%), P2O5 (0.02-0.05 wt.%) and MgO (0.01-0.30 wt.%, Mg# = 1.08-27.3), indicating they experienced fractional crystallization. Major element compositions suggest the potassic granites share an affinity with high K calc-alkaline granite. Even though the Lushan potassic granitic rocks have high A/CNK ratios (1.11-1.25), which can reach peraluminous feature, the very low P2O5 contents and negative correlation of P2O5 and SiO2 ruling out they are S-type granites. Different from peralkaline A-type granites, the Lushan potassic granites have variable Zr concentrations (160-344 ppm, 226 ppm on average) and 10,000 Ga/Al ratios (1.76-3.00), together with high zircon saturation temperatures (TZr = 826-885 °C), indicating they are fractionated aluminous A-type granites. Enriched LREE ((La/Yb)N = 9.72-81.8), negative Eu anomalies, and low Sr/Y with no correlations in Sr/Y and Sr/Zr versus CaO suggest the possible presence of Ca-rich plagioclase and absence of garnet in the residual. Magmatic zircon grains have variable εHf(t) values (-2.4 to +7.3) with zircon two-stage Hf model ages (TDMC) varying from 2848 Ma to 2306 Ma (mostly around ca. 2.5 Ga), and are plotted in the evolution line of crustal felsic rock. We propose that the rocks mainly formed by partial melting of ca. 2.50 Ga tonalitic-granodioritic crust as a result of upwelling mantle-derived magmas which provided thermal flux and source materials in an intra-continent rifting. The ca. 2.2 Ga magmatism suggests that intra-continental rifting occurred at 2.35-1.97 Ga at least in the southern margin of

  18. Regional reconstruction of subglacial hydrology and glaciodynamic behaviour along the southern margin of the Cordilleran Ice Sheet in British Columbia, Canada and northern Washington State, USA (United States)

    Lesemann, Jerome-Etienne; Brennand, Tracy A.


    Subglacial landsystems in and around Okanagan Valley, British Columbia, Canada are investigated in order to evaluate landscape development, subglacial hydrology and Cordilleran Ice Sheet dynamics along its southern margin. Major landscape elements include drumlin swarms and tunnel valleys. Drumlins are composed of bedrock, diamicton and glaciofluvial sediments; their form truncates the substrate. Tunnel valleys of various scales (km to 100s km length), incised into bedrock and sediment, exhibit convex longitudinal profiles, and truncate drumlin swarms. Okanagan Valley is the largest tunnel valley in the area and is eroded >300 m below sea level. Over 600 m of Late Wisconsin-age sediments, consisting of a fining-up sequence of cobble gravel, sand and silt fill Okanagan Valley. Landform-substrate relationships, landform associations, and sedimentary sequences are incompatible with prevailing explanations of landsystem development centred mainly on deforming beds. They are best explained by meltwater erosion and deposition during ice sheet underbursts. During the Late-Wisconsin glaciation, Okanagan Valley functioned as part of a subglacial lake spanning multiple connected valleys (few 100s km) of southern British Columbia. Subglacial lake development started either as glaciers advanced over a pre-existing sub-aerial lake (catch lake) or by incremental production and storage of basal meltwater. High geothermal heat flux, geothermal springs and/or subglacial volcanic eruptions contributed to ice melt, and may have triggered, along with priming from supraglacial lakes, subglacial lake drainage. During the underburst(s), sheetflows eroded drumlins in corridors and channelized flows eroded tunnel valleys. Progressive flow channelization focused flows toward major bedrock valleys. In Okanagan Valley, most of the pre-glacial and early-glacial sediment fill was removed. A fining-up sequence of boulder gravel and sand was deposited during waning stages of the underburst(s) and

  19. Uranium-Lead Ages of Lake Margin Tufa Calcite From the Middle Miocene Barstow Formation, Southern California (United States)

    Cole, J. M.; Rasbury, E. T.; Montañez, I. P.; Pedone, V. A.; Hemming, S. R.; Lanzirotti, A.; Becker, M. L.; Hanson, G. N.


    of just less than 1%. Our results show that lake margin tufa deposits as young as Miocene can preserve original U-Pb systematics and provide precise and concordant ages. This tool should be helpful in constraining the ages of similar sedimentary deposits that lack other datable materials.

  20. IODP Expedition 334: An Investigation of the Sedimentary Record, Fluid Flow and State of Stress on Top of the Seismogenic Zone of an Erosive Subduction Margin

    Directory of Open Access Journals (Sweden)

    Paola Vannucchi


    Full Text Available The Costa Rica Seismogenesis Project (CRISP is an experiment to understand the processes that control nucleation and seismic rupture of large earthquakes at erosional subduction zones. Integrated Ocean Drililng Program (IODP Expedition 334 by R/V JOIDES Resolution is the first step toward deep drilling through the aseismic and seismicplate boundary at the Costa Rica subduction zone offshore the Osa Peninsula where the Cocos Ridge is subducting beneath the Caribbean plate. Drilling operations included logging while drilling (LWD at two slope sites (Sites U1378 and U1379 and coring at three slope sites (Sites U1378–1380and at one site on the Cocos plate (Site U1381. For the first time the lithology, stratigraphy, and age of the slope and incoming sediments as well as the petrology of the subducting Cocos Ridge have been characterized at this margin.The slope sites recorded a high sediment accumulation rate of 160–1035m m.y.-1 possibly caused by on-land uplift triggered by the subduction of the Cocos Ridge. The geochemical data as well as the in situ temperature data obtained at the slope sites suggest that fluids are transported from greater depths. The geochemical profiles at Site U1381 reflect diffusional communication of a fluid with seawater-likechemistry and the igneous basement of the Cocos plate (Solomon et al., 2011; Vannucchi et al., 2012a. The present-day in situ stress orientation determined by borehole breakouts at Site U1378 in the middle slope and Site U1379 in the upper slope shows a marked change in stress state within ~12 km along the CRISP transect; that maycorrespond to a change from compression (middle slope to extension (upper slope.

  1. Crust and upper-mantle structure of Wanganui Basin and southern Hikurangi margin, North Island, New Zealand as revealed by active source seismic data (United States)

    Tozer, B.; Stern, T. A.; Lamb, S. L.; Henrys, S. A.


    Wide-angle reflection and refraction data recorded during the Seismic Array HiKurangi Experiment (SAHKE) are used to constrain the crustal P-wave velocity (Vp) structure along two profiles spanning the length and width of Wanganui Basin, located landwards of the southern Hikurangi subduction margin, New Zealand. These models provide high-resolution constraints on the structure and crustal thickness of the overlying Australian and subducted Pacific plates and plate interface geometry. Wide-angle reflections are modelled to show that the subducted oceanic Pacific plate crust is anomalously thick (∼10 km) below southern North Island and is overlain by a ∼1.5-4.0 km thick, low Vp (4.8-5.4 km s-1) layer, interpreted as a channel of sedimentary material, that persists landwards at least as far as Kapiti Island. Distinct near vertical reflections from onshore shots identify a ∼4 km high mound of low-velocity sedimentary material that appears to underplate the overlying Australian plate crust and is likely to contribute to local rock uplift along the Axial ranges. The overriding Australian plate Moho beneath Wanganui Basin is imaged as deepening southwards and reaches a depth of at least 36.4 km. The Moho shape approximately mirrors the thickening of the basin sediments, suggestive of crustal downwarping. However, the observed crustal thickness variation is insufficient to explain the large negative Bouguer gravity anomaly (-160 mGal) centred over the basin. Partial serpentinization within the upper mantle with a concomitant density decrease is one possible way of reconciling this anomaly.

  2. Crust and upper-mantle structure of Wanganui Basin and southern Hikurangi margin, North Island, New Zealand as revealed by active source seismic data (United States)

    Tozer, B.; Stern, T. A.; Lamb, S. L.; Henrys, S. A.


    Wide-angle reflection and refraction data recorded during the Seismic Array HiKurangi Experiment (SAHKE) are used to constrain the crustal P-wave velocity (Vp) structure along two profiles spanning the length and width of Wanganui Basin, located landwards of the southern Hikurangi subduction margin, New Zealand. These models provide high-resolution constraints on the structure and crustal thickness of the overlying Australian and subducted Pacific plates and plate interface geometry. Wide-angle reflections are modelled to show that the subducted oceanic Pacific plate crust is anomalously thick (˜10 km) below southern North Island and is overlain by a ˜1.5-4.0 km thick, low Vp (4.8-5.4 km s-1) layer, interpreted as a channel of sedimentary material, that persists landwards at least as far as Kapiti Island. Distinct near vertical reflections from onshore shots identify a ˜4 km high mound of low-velocity sedimentary material that appears to underplate the overlying Australian plate crust and is likely to contribute to local rock uplift along the Axial ranges. The overriding Australian plate Moho beneath Wanganui Basin is imaged as deepening southwards and reaches a depth of at least 36.4 km. The Moho shape approximately mirrors the thickening of the basin sediments, suggestive of crustal downwarping. However, the observed crustal thickness variation is insufficient to explain the large negative Bouguer gravity anomaly (-160 mGal) centred over the basin. Partial serpentinization within the upper mantle with a concomitant density decrease is one possible way of reconciling this anomaly.

  3. Southern elephant seals (Mirounga leonina Linn. depredate toothfish longlines in the midnight zone.

    Directory of Open Access Journals (Sweden)

    John van den Hoff

    Full Text Available Humans have devised fishing technologies that compete with marine predators for fish resources world-wide. One such fishery for the Patagonian toothfish (Dissostichus eleginoides has developed interactions with a range of predators, some of which are marine mammals capable of diving to extreme depths for extended periods. A deep-sea camera system deployed within a toothfish fishery operating in the Southern Ocean acquired the first-ever video footage of an extreme-diver, the southern elephant seal (Mirounga leonina, depredating catch from longlines set at depths in excess of 1000m. The interactions recorded were non-lethal, however independent fisheries observer reports confirm elephant seal-longline interactions can be lethal. The seals behaviour of depredating catch at depth during the line soak-period differs to other surface-breathing species and thus presents a unique challenge to mitigate their by-catch. Deployments of deep-sea cameras on exploratory fishing gear prior to licencing and permit approvals would gather valuable information regarding the nature of interactions between deep diving/dwelling marine species and longline fisheries operating at bathypelagic depths. Furthermore, the positive identification by sex and age class of species interacting with commercial fisheries would assist in formulating management plans and mitigation strategies founded on species-specific life-history strategies.

  4. Relations of zoned pegmatites to other pegmatites, granite, and metamorphic rocks in the southern Black Hills, South Dakota (United States)

    Norton, J.J.; Redden, J.A.


    The pegmatite field and the Harney Peak Granite of the southern Black Hills, South Dakota, form an igneous system that progresses from slightly biotitic muscovite granite through layered pegmatitic granite, with alternating sodic and potassic rocks, to simple plagioclase-quartz-perthite pegmatites, and on to zoned pegmatites. Most of the country rocks are Lower Proterozoic mica schists. At 1700 Ga, intrusion of the Harney Peak Granite created a large dome in these rocks, a thermal aureole with a staurolite, a first sillimanite isograd, and a small area of metamorphism above the second sillimanite isograd. The zoned pegmatites have a strong tendency to occur in clusters, and the types of pegmatites are different in different clusters. A less obvious tendency is a regional zonation in which rare-mineral pegmatites become more abundant and muscovite pegmatites less abundant toward the outskirts of the region. The composition of the granite indicates that its magma originated by partial melting of metasedimentary mica schists similar to those at the present surface. The pegmatitic nature of most of the granite probably reflects exsolution of an aqueous phase. -from Authors

  5. Paleoclimate and paleoceanographic reconstruction in the southern Iberian Mediterranean and Atlantic margins across the Younger Dryas event (United States)

    Rodrigo-Gámiz, Marta; Martínez-Ruiz, Francisca


    The Alboran Sea basin in the Mediterranean and the Gulf of Cadiz in the Atlantic have provided excellent paleoarchives for reconstructing past climate variability in southern Iberian regions. Particularly interesting has been the study of the paleoclimate evolution of abrupt climate events from the Last Glacial Maximum (LGM) to the onset of the Holocene such as the Younger Dryas (YD). A diverse range of geochemical proxies, integrating inorganic and organic, has been used for paleoclimate reconstructions in these regions. Elemental concentrations and elemental ratios have been used for determining detrital inputs and bottom water oxygen conditions while organic molecular biomarkers as algal and archaea derived lipids have been used for estimating sea surface temperature (SST). Al-ratios mirroring eolian input, such as Zr/Al and Si/Al ratios, record enhanced dust input at the end of the LGM, during the last Heinrich event (H1) and at the onset of the YD in the Alboran Sea. For this latest interval, these ratios suggest an initial dry phase followed by a progressive aridity decrease throughout the YD. In the Gulf of Cadiz, these variations are not similarly recorded, probably due to less sensitive open ocean records in comparison to the restricted nature of the Alboran Sea basin. Selected redox proxies, Fe/Al and Mn/Al ratios, show peaks of oxidation fronts during the LGM and the H1 in the Alboran Sea and during the Bölling-Alleröd and the onset of the Holocene in the Gulf of Cadiz, derived from variations in ventilation and oxygen conditions that differ in the Mediterranean and Atlantic regions. SST records have also showed remarkable differences between both basins with minima temperature estimated values during the YD of ca. 12°C in the Alboran Sea and ca. 18°C in the Gulf of Cadiz, according to the freshening of the Atlantic jet along the Alboran basin. In general, a different paleoclimate and oceanographic evolution with a different YD response is recorded

  6. Areas of residential development in the southern Appalachian Mountains are characterized by low riparian zone nitrogen cycling and no increase in soil greenhouse gas emissions (United States)

    Peter Baas; Jennifer D. Knoepp; Daniel Markewitz; Jacqueline E. Mohan


    The critical role streamside riparian zones play in mitigating the movement of nitrogen (N) and other elements from terrestrial to aquatic ecosystems could be threatened by residential development in the southern Appalachian Mountains. Many studies have investigated the influence of agriculture on N loading to streams but less is known about the impacts of residential...

  7. Geophysics in the Critical Zone: Constraints on Deep Weathering and Water Storage Potential in the Southern Sierra CZO (United States)

    Holbrook, W.; Riebe, C. S.; Hayes, J. L.; Reeder, K.; Harry, D. L.; Malazian, A. I.; Dosseto, A.; Hartsough, P. C.; Hopmans, J. W.


    Quantifying the depth and degree of subsurface weathering in landscapes is crucial for quantitative understanding of the biogeochemistry of weathering, the mechanics of hillslope sediment transport, and biogeochemical cycling of nutrients and carbon over both short and long timescales. Although the degree of weathering can be readily measured from geochemical and physical properties of regolith and rock, many distributed samples are needed to measure it over broad spatial scales. Moreover, quantifying the thickness of subsurface weathering has remained challenging, in part because the interface between altered and unaltered rock is often buried at difficult to access depths. To overcome these challenges, we combined seismic refraction and resistivity surveys to estimate regolith thickness and generate representative hillslope-scale images of subsurface weathering and water storage at the Southern Sierra Critical Zone Observatory (SSCZO). Inferred seismic velocities and electrical resistivities of the subsurface provide evidence for a weathering zone with thickness ranging from 10 to 35 m (average = 23 m) along one intensively studied transect. This weathering zone consists of roughly equal thicknesses of saprolite (P-velocity < 2 km/s) and moderately weathered bedrock (P-velocity < 4 km/s). We use a rock physics model of seismic velocities, based on Hertz-Mindlin contact theory, to estimate lateral and vertical variations in porosity as a metric of water storage potential along the transect. Inferred porosities are as high as 55% near the surface and decrease to zero at the base of weathered rock. Model-predicted porosities are broadly consistent with values measured from physical properties of saprolite, suggesting that our analysis of the geophysical data provides realistic estimates of subsurface water storage potential. A major advantage of our geophysical approach is that it quickly and non-invasively quantifies porosity over broad vertical and lateral scales

  8. Modern diatom assemblages as tools for paleoenvironmental reconstruction: a case study from estuarine intertidal zones in southern Iberia (United States)

    Gomes, Ana; Boski, Tomasz; Moura, Delminda; Szkornik, Katie; Witkowski, Andrzej; Connor, Simon; Laut, Lazaro; Sobrinho, Frederico; Oliveira, Sónia


    Diatoms are unicellular algae that live in saline, brackish and freshwater environments, either floating in the water column or associated with various substrates (e.g., muddy and sandy sediments). Diatoms are sensitive to changes in environmental variables such as salinity, sediment texture, nutrient availability, light and temperature. This characteristic, along with their short lifespan, allows diatoms to quickly respond to environmental changes. Since the beginning of the 20th century, diatoms have been widely used to study the Holocene evolution of estuaries worldwide, particularly to reconstruct ecological responses to sea-level and climate changes. However, diatoms have been poorly studied in estuarine intertidal zones, due to the complexity of these environments, which have both fluvial and marine influences. The aim of this study was to understand diatom diversity and spatial distribution in intertidal zones from two geomorphologically and hydrologically distinct estuaries. Sediment samples were collected from within the intertidal zones along the Arade and Guadiana River estuaries in southern Iberia. The sampling points embraced almost all the tidal and salinity gradients of both estuaries, capturing the highest possible environmental variability and hence of diatom assemblages. At each sampling point, the salinity and pH of the sediment interstitial water were measured. The sediment samples were subdivided for diatom identification, textural analysis and organic matter determination. All sampling points were georeferenced by DGPS and the duration of tidal inundation was calculated for each site. Following diatom identification, the data were analysed statistically (i.e. cluster analysis, PCA, DCA and RDA). The present study revealed that there is a great diatom diversity in both estuaries (418 species), with several species new to science. The most important diatom species (with abundances higher or equal to 5%) occur in five ecological groups, which are

  9. Marginal zone lymphoma of mucosa-associated lymphoid tissue with prominent plasma cell differentiation affecting the palatine tonsil: histopathological and immunohistochemical analysis. (United States)

    Carlos Bregni, Román; Nuyens, Michel; Vassallo, José; Soares, Fernando Augusto; Romañach, Mário José; León, Jorge Esquiche; Almeida, Oslei Paes


    Non-Hodgkin lymphomas (NHLs) of the oral cavity and oropharynx constitute 13% of all primary extranodal NHLs. Marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) in the palatine tonsil is rare, corresponding to 6% of the NHLs of the Waldeyer ring. Some cases of MALT lymphoma can present prominent plasma cell differentiation, and less commonly, monoclonal gammopathy. The differential diagnosis of these cases from other NHLs with plasmacytic differentiation or plasma cell neoplasms is very difficult. In this article, we describe a rare case of MALT lymphoma in a 34-year-old man presenting as a swelling of the palatine tonsil. The tumor mass was diagnosed as MALT lymphoma with prominent plasma cell differentiation. Systemic evaluation was noncontributory. This is the first report of MALT lymphoma showing extensive plasmacytic differentiation of the palatine tonsil, and reinforces a possible relationship between extramedullary plasmacytoma and MALT lymphoma. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. A minute focus of extranodal marginal zone B-cell lymphoma arising in Hashimoto thyroiditis diagnosed with PCR after laser capture microdissection: a case report

    Directory of Open Access Journals (Sweden)

    D'Antonio Antonio


    Full Text Available Abstract Background Primary thyroid gland lymphomas are uncommon tumours that occur in the setting of lymphocytic thyroiditis or Hashimoto's disease in almost all cases. In this condition a distinction between an inflammatory lymphoid infiltrate and a low grade lymphoma may be extremely difficult and precise criteria are necessary for a correct diagnosis. Patient and methods We report a case of a minute focus of primary extranodal marginal zone B-cell lymphoma (EMZBCL, incidentally discovered in a 63-year-old man with Hashimoto thyroiditis (HT and diagnosed by means of polymerase chain reaction (PCR after laser capture microdissection. The histological examination of surgical specimen confirmed the diagnosis of HT and showed a minute focus of dense lymphoid infiltrate (less than 4 mm in diameter, composed by centrocyte-like cells forming MALT balls. Immunoistochemistry was not useful. A microscopic focus of EMZBCL was suspected on the basis of morphological features. PCR assays revealed the rearrangement of the heavy chain of immunoglobulins only in the microdissected suspicious area, confirming the diagnosis of EMZBCL. Conclusion Our finding suggests that in cases of autoimmune thyroiditis a careful examination of the thyroid specimen is warranted, in order to disclose areas or small foci of lymphomatous transformation. Furthermore, in difficult cases with doubtful immunohistological findings, ancillary techniques, such as molecular studies, are necessary for a conclusive diagnosis.

  11. Rituximab monotherapy for splenic marginal zone lymphoma with villous lymphocytes: report on long-term disease control for two patients with recurrence after splenectomy

    Directory of Open Access Journals (Sweden)

    Márcio Debiasi

    Full Text Available CONTEXT: Splenic marginal zone lymphoma (SMZL is a lymphoproliferative B-cell disorder that has a favorable prognosis, with estimated overall five-year survival of 70%. The majority of symptomatic patients undergo splenectomy, while a few receive first-line chemotherapy, especially with purine analogues. There are no specific treatment guidelines for patients for whom splenectomy fails to provide a cure. It is still unclear whether these patients should undergo cytotoxic chemotherapy, considering they have now a relapsed lymphoma (which is theoretically more aggressive, or whether they should be spared from treatments of greater toxicity, given that their disease usually develops with a more indolent course, even when it recurs. CASE REPORT: Here, we present two patients whose disease recurred after splenectomy and for whom rituximab monotherapy provided satisfactory treatment. From these cases, it can be suggested that postponement of cytotoxic treatments may be possible in at least some situations. It needs to be emphasized that the evidence to support this approach is based only on case reports, since there are no randomized clinical trials on this subject.

  12. Multiple reactivation of a crustal-scale weakness zone - the Sveconorwegian Sokna-Saggrenda tectonic contact of southern Norway (United States)

    Scheiber, Thomas; Viola, Giulio; Peters, Max; Bingen, Bernard; Henderson, Iain


    The Sokna-Saggrenda tectonic contact (SSTC) is traditionally drawn on maps of southern Norway as the first-order, curved boundary between the Kongsberg-Modum terrane in the east and the Telemark terrane in the west, which were assembled during the Grenvillian-Sveconorwegian orogeny. New field observations along the entire length (120 km) of this deformation zone together with microstructural and textural data from selected transects suggest a more complex structural architecture and evolution than previously assumed. The following five structural elements resulting from several deformation episodes can be distinguished: (1) Amphibolite-facies mineral assemblages occurring together with a prominent E-dipping ductile foliation and a mineral lineation plunging moderately towards the NE. This fabric is associated with top-to-the-SW kinematics and is well preserved west of the SSTC. (2) Static overprint of the dynamically recrystallized quartz microstructure of (1) indicates cessation of deformation at relatively high temperatures. (3) (Ultra-)mylonites thoroughly overprinting the previous structures are confined to large-scale subvertical to moderately E-dipping shear zones bearing a gently SE-plunging stretching lineation. At the micro-scale, these structures are characterized by domains of older statically recrystallized quartz (2), being progressively reworked through dynamic recrystallization into quartz-rich aggregates. In the shear zone centers severe grain size reduction by mechanical comminution and phase mixing indicates granular flow. At the map-scale, the shear zones are arranged geometrically in a sinistral transpressional en-échelon network defining parts of the SSTC. Three crustal blocks can be identified as less-affected units in between these shear zones: the Telemark block, a western Kongsberg block and an eastern Modum block. A tens of kilometer-scale fold structure reorients the main ductile fabric (1) in the northern part of the Modum block and is

  13. Distribution of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and organochlorinated pollutants in deep-sea sediments of the Southern Cretan margin, Eastern Mediterranean Sea: a baseline assessment. (United States)

    Mandalakis, Manolis; Polymenakou, Paraskevi N; Tselepides, Anastasios; Lampadariou, Nikolaos


    Deep sediments from the southern Cretan margin were analyzed to establish baseline levels for various types of organic pollutants before the anticipated intensification of anthropogenic activities. The total concentration of aliphatic hydrocarbons (ΣAH:326-3758ngg(-1), dry weight) was similar to those reported for deep sediments of the western Mediterranean Sea, while considerably lower levels were measured for polycyclic aromatic hydrocarbons (ΣPAH:9-60ngg(-1)). Source-diagnostic ratios suggested that the aliphatic hydrocarbons in sediments were mainly of terrestrial biogenic origin, while polycyclic aromatic hydrocarbons stemmed from the deposition of long-range transported combustion aerosols. Among the organochlorinated compounds analyzed, β-hexachlorocyclohexane (β-HCH:222-7052pgg(-1)), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT:37-2236pgg(-1)) and polychlorinated biphenyls (ΣPCB:38-1182pgg(-1)) showed the highest abundance in sediments. The presence of HCHs and PCBs was attributed to historical inputs that have undergone extensive weathering, whereas an ongoing fresh input was suggested for p,p'-DDT. Multiple linear regression analysis revealed that the levels of the various pollutants in sediments were controlled by different factors, but with organic carbon content playing a prominent role in most cases. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Stratigraphic record of Pliocene-Pleistocene basin evolution and deformation within the Southern San Andreas Fault Zone, Mecca Hills, California (United States)

    McNabb, James C.; Dorsey, Rebecca J.; Housen, Bernard A.; Dimitroff, Cassidy W.; Messé, Graham T.


    A thick section of Pliocene-Pleistocene nonmarine sedimentary rocks exposed in the Mecca Hills, California, provides a record of fault-zone evolution along the Coachella Valley segment of the San Andreas fault (SAF). Geologic mapping, measured sections, detailed sedimentology, and paleomagnetic data document a 3-5 Myr history of deformation and sedimentation in this area. SW-side down offset on the Painted Canyon fault (PCF) starting 3.7 Ma resulted in deposition of the Mecca Conglomerate southwest of the fault. The lower member of the Palm Spring Formation accumulated across the PCF from 3.0 to 2.6 Ma during regional subsidence. SW-side up slip on the PCF and related transpressive deformation from 2.6 to 2.3 Ma created a time-transgressive angular unconformity between the lower and upper members of the Palm Spring Formation. The upper member accumulated in discrete fault-bounded depocenters until initiation of modern deformation, uplift, and basin inversion starting at 0.7 Ma. Some spatially restricted deposits can be attributed to the evolution of fault-zone geometric complexities. However, the deformation events at ca. 2.6 Ma and 0.7 Ma are recorded regionally along 80 km of the SAF through Coachella Valley, covering an area much larger than mapped fault-zone irregularities, and thus require regional explanations. We therefore conclude that late Cenozoic deformation and sedimentation along the SAF in Coachella Valley has been controlled by a combination of regional tectonic drivers and local deformation due to dextral slip through fault-zone complexities. We further propose a kinematic link between the 2.6-2.3 Ma angular unconformity and a previously documented but poorly dated reorganization of plate-boundary faults in the northern Gulf of California at 3.3-2.0 Ma. This analysis highlights the potential for high-precision chronologies in deformed terrestrial deposits to provide improved understanding of local- to regional-scale structural controls on basin

  15. Biological valorisation of the southern Baltic Sea (Polish Exclusive Economic Zone

    Directory of Open Access Journals (Sweden)

    Jan Marcin Węsławski


    Full Text Available A biological valuation system to assess the value associated with ecosystem stability and richness (and not that from the point of view of users is proposed to provide scientific decision support for marine protected areas and marine spatial planning. The system is based on the assessment of individual species and habitat/species assemblages. An extensive set of recently collected (2007-08 and archival (1970-2000 data on the occurrence of marine benthos was analysed for the Polish Marine Areas. Based on matching data sets of sediments, the euphotic zone, temperature and salinity, as well as fetch and sea current values, a GIS model was used to visualise the results; a map indicates the two areas which are considered to be biologically the most valuable (Puck Bay and the stony shallows of the central coast.

  16. Tertiary plutonic rocks of southern Serbia Vardar Zone as dimension stone

    Directory of Open Access Journals (Sweden)

    Kurešević Lidja


    Full Text Available Three granitoid plutons of south-Serbian part of the Vardar Zone, of Tertiary age were studied in order to establish their potential for utilization as dimension stone. These rocks vary in composition from quartzmonconite to quartzdiorite. Field study aimed at establishing the geological factors - presence of fractures, harmful minerals, alterations, jointing type and fabric homogeneity in order to determine the possibility of obtaining large size blocks of stone from the plutons. Laboratory examinations comprised petrological analyses and testing of technical properties. Stone from these plutons has shown favourable results in both field and laboratory examinations. Evaluation of the rock based on obtained laboratory testing results is performed according to technical requirements of the Serbian standard B.B3.200. It has shown that rocks from these plutons can be used as dimension stone for the production of slabs for the exterior and interior paving and cladding. [Projekat Ministarstva nauke Republike Srbije, br. OI176016

  17. Late Quaternary strike-slip along the Taohuala Shan-Ayouqi fault zone and its tectonic implications in the Hexi Corridor and the southern Gobi Alashan, China (United States)

    Yu, Jing-xing; Zheng, Wen-jun; Zhang, Pei-zhen; Lei, Qi-yun; Wang, Xu-long; Wang, Wei-tao; Li, Xin-nan; Zhang, Ning


    The Hexi Corridor and the southern Gobi Alashan are composed of discontinuous a set of active faults with various strikes and slip motions that are located to the north of the northern Tibetan Plateau. Despite growing understanding of the geometry and kinematics of these active faults, the late Quaternary deformation pattern in the Hexi Corridor and the southern Gobi Alashan remains controversial. The active E-W trending Taohuala Shan-Ayouqi fault zone is located in the southern Gobi Alashan. Study of the geometry and nature of slip along this fault zone holds crucial value for better understanding the regional deformation pattern. Field investigations combined with high-resolution imagery show that the Taohuala Shan fault and the E-W trending faults within the Ayouqi fault zone (F2 and F5) are left-lateral strike-slip faults, whereas the NW or WNW-trending faults within the Ayouqi fault zone (F1 and F3) are reverse faults. We collected Optically Stimulated Luminescence (OSL) and cosmogenic exposure age dating samples from offset alluvial fan surfaces, and estimated a vertical slip rate of 0.1-0.3 mm/yr, and a strike-slip rate of 0.14-0.93 mm/yr for the Taohuala Shan fault. Strata revealed in a trench excavated across the major fault (F5) in the Ayouqi fault zone and OSL dating results indicate that the most recent earthquake occurred between ca. 11.05 ± 0.52 ka and ca. 4.06 ± 0.29 ka. The geometry and kinematics of the Taohuala Shan-Ayouqi fault zone enable us to build a deformation pattern for the entire Hexi Corridor and the southern Gobi Alashan, which suggest that this region experiences northeastward oblique extrusion of the northern Tibetan Plateau. These left-lateral strike-slip faults in the region are driven by oblique compression but not associated with the northeastward extension of the Altyn Tagh fault.

  18. Patterns of forest composition and their long term environmental drivers in the tropical dry forest transition zone of southern Africa

    Directory of Open Access Journals (Sweden)

    Vera De Cauwer


    Full Text Available Background Tropical dry forests cover less than 13 % of the world’s tropical forests and their area and biodiversity are declining. In southern Africa, the major threat is increasing population pressure, while drought caused by climate change is a potential threat in the drier transition zones to shrub land. Monitoring climate change impacts in these transition zones is difficult as there is inadequate information on forest composition to allow disentanglement from other environmental drivers. Methods This study combined historical and modern forest inventories covering an area of 21,000 km2 in a transition zone in Namibia and Angola to distinguish late succession tree communities, to understand their dependence on site factors, and to detect trends in the forest composition over the last 40 years. Results The woodlands were dominated by six tree species that represented 84 % of the total basal area and can be referred to as Baikiaea - Pterocarpus woodlands. A boosted regression tree analysis revealed that late succession tree communities are primarily determined by climate and topography. The Schinziophyton rautanenii and Baikiaea plurijuga communities are common on slightly inclined dune or valley slopes and had the highest basal area (5.5 – 6.2 m2 ha−1. The Burkea africana - Guibourtia coleosperma and Pterocarpus angolensis – Dialium englerianum communities are typical for the sandy plateaux and have a higher proportion of smaller stems caused by a higher fire frequency. A decrease in overall basal area or a trend of increasing domination by the more drought and cold resilient B. africana community was not confirmed by the historical data, but there were significant decreases in basal area for Ochna pulchra and the valuable fruit tree D. englerianum. Conclusions The slope communities are more sheltered from fire, frost and drought but are more susceptible to human expansion. The community with the important timber tree P

  19. Study on the prevalence of Foot and Mouth Disease in Borana and Guji Zones, Southern Ethiopia

    Directory of Open Access Journals (Sweden)

    Ashenafi Feyisa and Fufa Abunna

    Full Text Available A cross sectional study was conducted on Borana plateau and Guji highlands of southern Ethiopia to determine the prevalence of Foot and Mouth Disease (FMD in bovine species. Seroprevalence investigation was performed using 3ABC- ELISA technique. The result indicated that the overall prevalence of Foot and Mouth Disease was 24.6 %(113/460. Significantly higher prevalence was recorded in Borana 53.6 % ( 82/153 compared to Guji 10.1 %( 31/307. From the various risk factors, geographical distribution (÷²=104.26, P<0.05 and age (÷²=6.68, P<0.05 were seen to be significantly associated with the seroprevalence. The result of this study indicated that FMD is highly prevalent in lowland area (Borana than highland (Guji due to contact of different origin cattle in search of feed and water. The presence of higher prevalence of Foot and Mouth Disease in pastoralists\\\\\\\\\\\\\\' cattle of the area warrants further investigation and characterization of the circulating virus serotype to apply effective control and prevention measures. [Vet. World 2011; 4(7.000: 293-296

  20. Fault zone characteristics and basin complexity in the southern Salton Trough, California (United States)

    Persaud, Patricia; Ma, Yiran; Stock, Joann M.; Hole, John A.; Fuis, Gary S.; Han, Liang


    Ongoing oblique slip at the Pacific–North America plate boundary in the Salton Trough produced the Imperial Valley (California, USA), a seismically active area with deformation distributed across a complex network of exposed and buried faults. To better understand the shallow crustal structure in this region and the connectivity of faults and seismicity lineaments, we used data primarily from the Salton Seismic Imaging Project to construct a three-dimensional P-wave velocity model down to 8 km depth and a velocity profile to 15 km depth, both at 1 km grid spacing. A VP = 5.65–5.85 km/s layer of possibly metamorphosed sediments within, and crystalline basement outside, the valley is locally as thick as 5 km, but is thickest and deepest in fault zones and near seismicity lineaments, suggesting a causative relationship between the low velocities and faulting. Both seismicity lineaments and surface faults control the structural architecture of the western part of the larger wedge-shaped basin, where two deep subbasins are located. We estimate basement depths, and show that high velocities at shallow depths and possible basement highs characterize the geothermal areas.

  1. Agrogenic transformation of soil organic C in conditions of southern-taiga zone, European Russia (United States)

    Yashin, Ivan; Vasenev, Ivan; Atenbekov, Ramiz


    The principal regional features of soil organic carbon (SOC) agrogenic transformation and water-soluble organic substances (WSOS) genesis and environmental functions have been investigated in the Podzols and Podzoluvisols of the representative natural and agro- ecosystems in the southern taiga subzone of the European part of Russia. Especial attention has been done to the role of SOC agrogenic degradation and WSOS with acidic and ligand properties in soil carbon dioxide emission. The long-term agroecological investigations run in the regional set of representative agrolandscape monitoring stations in the educational farm "Mikhailovskoye" (Podolsk district, Moscow region), Field experimental station and Forest experimental station (RTSAU campus, Moscow) and in the Central Forest biosphere reserve (Nelidovo district, Tver region). Field research methods include sorption lysimetry and radioactive tracers. The laboratory ones - chromatography and spectrophotometry. There were used activated charcoal brand "Carbolite", chemically purified quartz sand and barley plant residues (2-3 mm), totally labeled with 14C in the soil-horizontally distributed sorption columns. Obtained results became useful for quantitative assessment of the principal stages and processes in soil CO2 emission, including the water-soluble organic substances formation (3.0 g of SOC per 100 g of plant litter or 60-75 g of SOC per square meter of the organo-mineral horizon A0 per year) and CO2 emission. In the middle taiga ecosystem conditions (with relatively low soil biological activity) the highest emission of CO2 (83,0±4.1 % of the newly formed WSOS) was in case of arable Podzoluvisols, and lowest one (32,4±2,5%) - in their semihydromorphic versions.

  2. Human response and adaptation to drought in the arid zone: lessons from southern Africa

    Directory of Open Access Journals (Sweden)

    W. R.J. Dean


    Full Text Available Human adaptation and response to drought is primarily through evasion or endurance. A review of historical agricultural practices in southern Africa demonstrates evidence of drought evasion response strategies in well-established transhumance routes, where herders move livestock on a seasonal basis in order to exploit resources subject to different climatic regimes. European settlers to the arid regions of South Africa quickly recognised the necessity of these evasion options to survive drought, and adopted the transhumance practices of indigenous farmers. Areas of geographically diverse resource bases became hotly contested by settlers and indigenous farmers. The success of evasion systems are shown to hinge on good social and institutional support structures. When movement is not an option, drought endurance is pursued by attempting to limit the damage to the natural resource base. This is through a number of means such as forage conservation, varying livestock types and numbers, water and soil conservation and taking up alternative livelihood options. State responses to drought over the last century reflect the general South African pattern of racially divided and unjust policies relating to resource access. Historically the state provided considerable support to white commercial farmers. This support was frequently contradictory in its aims and generally was inadequate to enable farmers to cope with drought. Since the advent of democracy in 1994, the state has intervened less, with some support extended to previously disadvantaged and poor communal farmers. Climate change predictions suggest an increase in drought, suggesting that the adoption of mitigating strategies should be a matter of urgency. To do this South Africa needs to build social and institutional capacity, strive for better economic and environmental sustainability, embed drought-coping mechanisms into land restitution policy to ensure the success of this programme, and

  3. Seismogenic rotational slumps and translational glides in pelagic deep-water carbonates. Upper Tithonian-Berriasian of Southern Tethyan margin (W Sicily, Italy) (United States)

    Basilone, Luca


    related to local-scale faults. To explain the translational glides of the upper portion of the section, the aforementioned outside sector earthquakes produced instability of the sea-floor through thixotropy of marls. In this case, the driving forces (i.e., gravitational) were favoured by the uplifting trend that is well recorded in the Southern Tethyan continental margin. We suggest that the various early deformations represent rotational slump and sediment creep that may be characteristic for slump structures in pelagic carbonates, depending on the involved lithologies (i.e., paleoenvironmental setting) and the intensity/distance of the trigger mechanism (i.e., earthquake epicentre).

  4. Negative role of TAK1 in marginal zone B-cell development incidental to NF-κB noncanonical pathway activation. (United States)

    Shinohara, Hisaaki; Kurosaki, Tomohiro


    The transcription factor nuclear factor-κB (NF-κB) signaling pathway is crucial in B-cell physiology. One key molecule regulating this pathway is the serine/threonine kinase TAK1 (MAP3K7). TAK1 is responsible for positive feedback mechanisms in B-cell receptor signaling that serve as an NF-κB activation threshold. This study aimed to better understand the correlation between TAK1-mediated signaling and B-cell development and humoral immune responses. Here we showed that a B-cell conditional deletion of TAK1 using mb1-cre resulted in a dramatic elimination of the humoral immune response, consistent with the absence of the B-1 B-cell subset. When monitoring the self-reactive B-cell system (the immunoglobulin hen egg lysozyme/soluble hen egg lysozyme double-transgenic mouse model), we found that TAK1-deficient B cells exhibited an enhanced susceptibility to cell death that might explain the disappearance of the B1 subset. In contrast, these mice gained numerous marginal zone (MZ) B cells. We consequently examined the basal and B-cell receptor-induced activity of NF-κB2 that is reported to regulate MZ B-cell development, and demonstrated that the activity of NF-κB2 increased in TAK1-deficient B cells. Thus, our results present a novel in vivo function, the negative role of TAK1 in MZ B-cell development that is likely associated with NF-κB2 activation.

  5. Radiation Therapy Administration and Survival in Stage I/II Extranodal Marginal Zone B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue

    Energy Technology Data Exchange (ETDEWEB)

    Olszewski, Adam J., E-mail:; Desai, Amrita


    Purpose: To determine the factors associated with the use of radiation therapy and associated survival outcomes in early-stage marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT). Methods and Materials: We extracted data on adult patients with stage I/II MALT lymphoma diagnoses between 1998 and 2010 recorded in the Surveillance, Epidemiology, and End Results (SEER) database. We studied factors associated with radiation therapy administration in a logistic regression model and described the cumulative incidence of lymphoma-related death (LRD) according to receipt of the treatment. The association of radiation therapy with survival was explored in multivariate models with adjustment for immortal time bias. Results: Of the 7774 identified patients, 36% received radiation therapy as part of the initial course of treatment. Older patients; black or Hispanic men; white, Hispanic, and black women; and socioeconomically disadvantaged and underinsured patients had a significantly lower chance of receiving radiation therapy. Radiation therapy administration was associated with a lower chance of LRD in most sites. In cutaneous, ocular, and salivary MALT lymphomas, the 5-year estimate of LRD after radiation therapy was 0%. The association of radiation therapy with overall survival in different lymphoma sites was heterogeneous, and statistically significant in cutaneous (hazard ratio 0.45, P=.009) and ocular (hazard ratio 0.47, P<.0001) locations after multivariate adjustment. Conclusions: Demographic factors are associated with the use of radiation therapy in MALT lymphoma. Clinicians should be sensitive to those disparities because the administration of radiation therapy may be associated with improved survival, particularly in cutaneous and ocular lymphomas.

  6. Notch-RBP-J-independent marginal zone B cell development in IgH transgenic mice with VH derived from a natural polyreactive antibody. (United States)

    Zhang, Zhuo; Zhou, Lanhua; Yang, Xinwei; Wang, Yaochun; Zhang, Ping; Hou, Lihong; Hu, Xinbin; Xing, Ying; Liu, Yufeng; Li, Wei; Han, Hua


    Both the B cell antigen receptor (BCR) signaling and Notch signaling pathway play important roles in marginal zone (MZ) B cell development; however, if and how these two signaling pathways engage in crosstalk with each other remain unclear. In the present study, IgH transgenic mice (TgV(H)3B4) were crossed with mice with Notch downstream transcription factor RBP-J floxed alleles (RBP-J(f/f)) and Mx-Cre transgene. Subsequently, MZ B cell development was analyzed in 3B4/Cre/RBP-J(f/f) mice that expressed the transgenic 3B4 IgH and exhibited a deficiency in Notch signaling in B cells upon poly (I:C) injection. We observed that MZ B cell numbers were severely reduced, but still detectable in 3B4/Cre/RBP-J(f/f) mice, in contrast to increased numbers of MZ B cells in TgV(H)3B4 mice and almost no MZ B cells in Cre/RBP-J(f/f) mice. The majority of the MZ B cells in the 3B4/Cre/RBP-J(f/f) mice had the same antigen specificity with that of 3B4 antibody, indicating that a particular BCR specificity might direct MZ B cell development in the absence of Notch signaling. The number of MZ B precursor (MZP) cells was reduced sharply in 3B4/Cre/RBP-J(f/f) mice, and the number of transitional stage 1 and transitional stage 2 cells did not change that much, indicating that the interaction between BCR and Notch signaling likely occurred during the T2-MZP stage. Based on the transgenic mouse model, our data indicate that MZ B cells with certain BCR specificity can develop in a Notch-RBP-J independent manner.

  7. Notch-RBP-J-independent marginal zone B cell development in IgH transgenic mice with VH derived from a natural polyreactive antibody.

    Directory of Open Access Journals (Sweden)

    Zhuo Zhang

    Full Text Available Both the B cell antigen receptor (BCR signaling and Notch signaling pathway play important roles in marginal zone (MZ B cell development; however, if and how these two signaling pathways engage in crosstalk with each other remain unclear. In the present study, IgH transgenic mice (TgV(H3B4 were crossed with mice with Notch downstream transcription factor RBP-J floxed alleles (RBP-J(f/f and Mx-Cre transgene. Subsequently, MZ B cell development was analyzed in 3B4/Cre/RBP-J(f/f mice that expressed the transgenic 3B4 IgH and exhibited a deficiency in Notch signaling in B cells upon poly (I:C injection. We observed that MZ B cell numbers were severely reduced, but still detectable in 3B4/Cre/RBP-J(f/f mice, in contrast to increased numbers of MZ B cells in TgV(H3B4 mice and almost no MZ B cells in Cre/RBP-J(f/f mice. The majority of the MZ B cells in the 3B4/Cre/RBP-J(f/f mice had the same antigen specificity with that of 3B4 antibody, indicating that a particular BCR specificity might direct MZ B cell development in the absence of Notch signaling. The number of MZ B precursor (MZP cells was reduced sharply in 3B4/Cre/RBP-J(f/f mice, and the number of transitional stage 1 and transitional stage 2 cells did not change that much, indicating that the interaction between BCR and Notch signaling likely occurred during the T2-MZP stage. Based on the transgenic mouse model, our data indicate that MZ B cells with certain BCR specificity can develop in a Notch-RBP-J independent manner.

  8. Long-Term Outcomes and Patterns of Relapse of Early-Stage Extranodal Marginal Zone Lymphoma Treated With Radiation Therapy With Curative Intent

    Energy Technology Data Exchange (ETDEWEB)

    Teckie, Sewit; Qi, Shunan; Lovie, Shona [Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York (United States); Navarrett, Scott [Weill Cornell Medical College, New York, New York (United States); Hsu, Meier [Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, New York (United States); Noy, Ariela; Portlock, Carol [Lymphoma Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York (United States); Yahalom, Joachim, E-mail: [Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York (United States)


    Purpose: To report the long-term outcome and patterns of relapse of a large cohort of marginal zone lymphoma (MZL) patients treated with curative-intent radiation therapy (RT) alone. Patients and Methods: We reviewed the charts of 490 consecutive patients with stage IE or IIE MZL referred between 1992 and 2012 to our institution. Of those, 244 patients (50%) were treated with RT alone. Pathology was confirmed by hematopathologists at our institution. Patient and disease factors were analyzed for association with relapse-free survival (RFS) and overall survival (OS). Results: Median age of the cohort was 59 years, and median follow-up was 5.2 years. Ann Arbor stage was IE in 92%. Most common disease sites were stomach (50%), orbit (18%), non-thyroid head-and-neck (8%), skin (8%), and breast (5%). Median RT dose was 30 Gy. Five-year OS and RFS were 92% and 74%, respectively. Cumulative incidence of disease-specific death was just 1.1% by 5 years. Sixty patients (24%) developed relapse of disease; 10 were in the RT field. Crude rate of transformation to pathologically confirmed large-cell lymphoma was 1.6%. On multivariable analysis, primary disease site (P=.007) was independently associated with RFS, along with age (P=.04), presence of B-symptoms (P=.02), and International Prognostic Index risk group (P=.03). All disease sites except for head-and-neck had worse RFS relative to stomach. Conclusion: Overall and cause-specific survival are high in early-stage extra-nodal MZL treated with curative RT alone. In this large cohort of 244 patients, most patients did not experience relapse of MZL after curative RT; when relapses did occur, the majority were in distant sites. Stomach cases were less likely to relapse than other anatomic sites. Transformation to large-cell lymphoma was rare.

  9. AL Amyloidoma of the Skin/Subcutis: Cutaneous Amyloidosis, Plasma Cell Dyscrasia or a Manifestation of Primary Cutaneous Marginal Zone Lymphoma? (United States)

    Walsh, Noreen M; Lano, Ian Marie; Green, Peter; Gallant, Christopher; Pasternak, Sylvia; Ly, Thai Yen; Requena, Luis; Kutzner, Heinz; Chott, Andreas; Cerroni, Lorenzo


    It is unclear whether AL amyloidoma of the skin/subcutis represents a distinct entity, an indolent precursor of systemic amyloidosis, or a manifestation of cutaneous marginal zone lymphoma (cMZL). We collected 10 cases of cutaneous AL amyloidoma in order to better characterize the clinicopathologic features of this elusive entity (M:F=4:6; median age: 62.5 y, range: 31 to 82 y). Nine patients had a solitary nodule or plaque on the lower extremity (n=7), upper extremity (n=1), or chin (n=1). One patient had an AL amyloidoma on the right thigh and a second lesion on the right arm showing histopathologic features of cMZL without amyloid deposits. Clinical investigations excluded relevant systemic disease in all cases. Microscopically, dermal/subcutaneous deposits of amyloid were associated with sparse to moderate perivascular infiltrates of lymphocytes and monotypic plasma cells (7 with kappa and 3 with lambda light chain restriction). The plasma cells expressed CD56 in one of 9 studied cases. One case was characterized by a t(14;18)(q32;q21)/IGH-MALT1 translocation. Follow-up was available in 8 cases. All remain systemically well after a median time of 86.5 months (range: 40 to 144 mo). Local recurrence of disease was observed in 3 patients. A fourth patient presented with a cMZL without amyloid deposits 8 years after excision of the cutaneous AL amyloidoma. Although our series is small, careful categorization and follow-up of the cases, together with updated information in the literature, show clinical and biological links between AL amyloidomas of the skin/subcutis and cMZL, suggesting that at least a subset of cutaneous AL amyloidoma may represent an unusual manifestation of cMZL (cutaneous mucosa-associated lymphoid tissue lymphomas).

  10. Wetlands as principal zones of methylmercury production in southern Louisiana and the Gulf of Mexico region. (United States)

    Hall, B D; Aiken, G R; Krabbenhoft, D P; Marvin-Dipasquale, M; Swarzenski, C M


    It is widely recognized that wetlands, especially those rich in organic matter and receiving appreciable atmospheric mercury (Hg) inputs, are important sites of methylmercury (MeHg) production. Extensive wetlands in the southeastern United States have many ecosystem attributes ideal for promoting high MeHg production rates; however, relatively few mercury cycling studies have been conducted in these environments. We conducted a landscape scale study examining Hg cycling in coastal Louisiana (USA) including four field trips conducted between August 2003 and May 2005. Sites were chosen to represent different ecosystem types, including: a large shallow eutrophic estuarine lake (Lake Pontchartrain), three rivers draining into the lake, a cypress-tupelo dominated freshwater swamp, and six emergent marshes ranging from a freshwater marsh dominated by Panicum hemitomon to a Spartina alterniflora dominated salt marsh close to the Gulf of Mexico. We measured MeHg and total Hg (THg) concentrations, and ancillary chemical characteristics, in whole and filtered surface water, and filtered porewater. Overall, MeHg concentrations were greatest in surface water of freshwater wetlands and lowest in the profundal (non-vegetated) regions of the lake and river mainstems. Concentrations of THg and MeHg in filtered surface water were positively correlated with the highly reactive, aromatic (hydrophobic organic acid) fraction of dissolved organic carbon (DOC). These results suggest that DOC plays an important role in promoting the mobility, transport and bioavailability of inorganic Hg in these environments. Further, elevated porewater concentrations in marine and brackish wetlands suggest coastal wetlands along the Gulf Coast are key sites for MeHg production and may be a principal source of MeHg to foodwebs in the Gulf of Mexico. Examining the relationships among MeHg, THg, and DOC across these multiple landscape types is a first step in evaluating possible links between key zones for

  11. Spatial/temporal patterns of Quaternary faulting in the southern limb of the Yellowstone-Snake River Plain seismic parabola, northeastern Basin and Range margin

    Energy Technology Data Exchange (ETDEWEB)

    McCalpin, J.P. (GEO-HAZ Consultants, Estes Park, CO (United States))


    During the period 1986--1991, 11 backhoe trenches were excavated across six Quaternary faults on the northeastern margin of the Basin and Range province. These faults comprise the southern limb of a parabola of Quaternary faults and historic moderate-magnitude earthquakes which is roughly symmetrical about the Snake River Plain, and heads at the Yellowstone hot spot. Fifteen Holocene paleoseismic events have been bracketed by radiocarbon or thermoluminescence ages. On the six central faults, the latest rupture event occurred in a relatively short time interval between 3 ka and 6 ka. The period between 6 ka and the end of the latest glaciation (ca. 15 ka) was a period of relative tectonic quiescence on the central faults, but not on the two end faults with higher slip rates (Wasatch and Teton faults). Southward-younging of events in the 3--6 ka period may indicate that temporally-clustered faulting was initiated at the Yellowstone hot spot. Faults at the same latitude, such as the Star Valley-Grey's River pair of faults, or the East Cache-Bear Lake-Rock Creek system of faults, show nearly identical timing of latest rupture events within the pairs or systems. Faults at common latitudes probably sole into the same master decollement, and thus are linked mechanically like dominoes. The timing of latest ruptures indicates that faulting on the westernmost fault preceded faulting on successively more eastern faults by a few hundred years. This timing suggests that slip on the westernmost faults mechanically unloaded the system, causing tectonic instabilities farther east.

  12. Petrology and petrogenesis of Mesoproterozoic lamproites from the Ramadugu field, NW margin of the Cuddapah basin, Eastern Dharwar craton, southern India (United States)

    Chalapathi Rao, N. V.; Kumar, Alok; Sahoo, Samarendra; Dongre, A. N.; Talukdar, Debojit


    Petrography, mineral chemistry, and major and trace element data are presented for the newly discovered Mesoproterozoic (1.33-1.43 Ga) lamproites from the Ramadugu field (RLF), at the NW margin of the Paleo-Mesoproterozoic Cuddapah basin, in the Eastern Dharwar craton (EDC), southern India. RLF lamproites are emplaced as dykes, have a NW-SE trend and their petrography reveal the effects of low-temperature alteration. However, their textural features, mineralogy and geochemistry are closely similar to other well-characterised lamproites worldwide, including examples from the Eastern Dharwar craton, Leucite Hills, West Kimberley, Smoky Butte and Labrador. The RLF magmas have undergone varying degrees of olivine + clinopyroxene fractionation; yet their compatible and incompatible trace element concentrations are sufficiently high to signal a primitive character. Incompatible element ratios suggest limited contamination by continental crust. Geochemical evidence indicates the derivation of RLF magmas from metasomatised harzburgite within the garnet stability field. Rare earth element inversion modelling further highlights substantial involvement of the sub-continental lithospheric mantle in their genesis. The RLF lamproites are geochemically similar to the well-known extension-related ultrapotassic lavas from eastern Virunga and western Anatolia, and exclude an affinity with orogenic lamproites, such as those from the Mediterranean region. Bulk-rock geochemical models, recently developed to infer diamond potential, reveals that RLF lamproites are non-prospective. Lamproites of the RLF, together with those from the Krishna lamproite field and Cuddapah basin are interpreted as an expression of extensional events in the Eastern Dharwar craton possibly related to the break-up of the supercontinent of Columbia between 1.5 and 1.3 Ga.

  13. Instability and deformation in the sedimentary cover on the upper slope of the southern Aquitaine continental margin, north of the Capbreton canyon (Bay of Biscay

    Directory of Open Access Journals (Sweden)

    Eliane Gonthier


    Full Text Available Acoustic and core data have recently been collected on the shelf break and the upper part of the slope of the south Aquitaine continental margin. They reveal the major role played by mass-flow gravity processes in deposit erosion and redistribution, modelling of the sea-bed, and transfer of sediment toward the deep-sea. The study region is bounded in the south by the Capbreton canyon. The northern area, which shows a smooth morphology, is characterised by small-scale deformations due to sediment creep or low-amplitude slide processes. The deformations are associated with mini listric-like faults that bound packets of sediments in which the deposit geometry is typical of constructional sediment waves. These sediment waves result from the interaction of depositional and gravity deformation processes. In the southern area, closer to the canyon, wave-like structures are still present but mostly of smaller size. They only result from gravity deformation processes without any evidence of constructional processes. In the vicinity of the Capbreton canyon, the shelf break and upper slope have a much more uneven morphology with sedimentary reliefs, escarpments and depressions directed toward the canyon thalweg. The depressions look like slide scars, and could be the result of regressive slides initiated at the top of the canyon flank. The age of the sliding event responsible for the formation of the depression observed today could be middle to upper Quaternary. Since their formation, these depressions act as conduits that channel the transfer of shelf sediment into the canyon, as demonstrated by the occurrence of a meandering channel on the sea-floor of one depression.

  14. Late Pleistocene to Holocene sedimentation and hydrocarbon seeps on the continental shelf of a steep, tectonically active margin, southern California, USA (United States)

    Draut, Amy E.; Hart, Patrick E.; Lorenson, T.D.; Ryan, Holly F.; Wong, Florence L.; Sliter, Ray W.; Conrad, James E.


    Small, steep, uplifting coastal watersheds are prolific sediment producers that contribute significantly to the global marine sediment budget. This study illustrates how sedimentation evolves in one such system where the continental shelf is largely sediment-starved, with most terrestrial sediment bypassing the shelf in favor of deposition in deeper basins. The Santa Barbara-Ventura coast of southern California, USA, is considered a classic area for the study of active tectonics and of Tertiary and Quaternary climatic evolution, interpretations of which depend upon an understanding of sedimentation patterns. High-resolution seismic-reflection data over >570 km2 of this shelf show that sediment production is concentrated in a few drainage basins, with the Ventura and Santa Clara River deltas containing most of the upper Pleistocene to Holocene sediment on the shelf. Away from those deltas, the major factor controlling shelf sedimentation is the interaction of wave energy with coastline geometry. Depocenters containing sediment 5-20 m thick exist opposite broad coastal embayments, whereas relict material (bedrock below a regional unconformity) is exposed at the sea floor in areas of the shelf opposite coastal headlands. Locally, natural hydrocarbon seeps interact with sediment deposition either to produce elevated tar-and-sediment mounds or as gas plumes that hinder sediment settling. As much as 80% of fluvial sediment delivered by the Ventura and Santa Clara Rivers is transported off the shelf (some into the Santa Barbara Basin and some into the Santa Monica Basin via Hueneme Canyon), leaving a shelf with relatively little recent sediment accumulation. Understanding factors that control large-scale sediment dispersal along a rapidly uplifting coast that produces substantial quantities of sediment has implications for interpreting the ancient stratigraphic record of active and transform continental margins, and for inferring the distribution of hydrocarbon resources

  15. Separation of the Guajira-Bonaire pair in the southern margin of the Caribbean: 65-50 Ma exhumation followed by 300 km right-lateral transtensional deformation (United States)

    Zapata Henao, S.; Cardona, A.; Montes, C.; Valencia, V.; Vervoort, J. D.; Reiners, P. W.


    Middle to upper Eocene fluvial strata in the island of Bonaire contains detrital components that were tracked to the basement massifs of the Guajira Peninsula in northern Colombia. These detrital components confirm previous hypothesis that the Guajira-Bonaire pair constitute a tectonic piercing point along the southern Caribbean plate margin that was right-laterally displaced approximately 300 km after middle Eocene times. Other possible sources, the nearby Curacao and the far away Santa Marta massif, did not pass statistical similarity and overlap tests. U-Pb LA-ICP-MS from the metamorphic boulders of the Soebi Blanco Formation in Bonaire yield Grenvillian ages (1084 Ma, 1130 Ma and 1184 Ma), while the detrital zircons recovered from the sandy matrix of the conglomerates contains populations with peaks of 1000 Ma - 1200 Ma, 750 Ma - 950 Ma, and 200 Ma - 300 Ma. Overlap and Similarity tests run between these populations and published data from Guajira yield values of 0.750 and 0.680, which are significantly higher than the same comparison against the Santa Marta Massif (0.637 and 0.522), and the Curacao island (0.629 and 0.467). Thermochronological results from the metamorphic clasts yield Paleocene-middle Eocene ages (65 - 50 Ma) that confirm not only a regional-scale cooling event in this time period, but also help constrain the maximum depositional age (50 Ma) of the poorly dated Soebi Blanco Formation. Figure 6. U-Pb results from analyzed samples and other Caribbean provinces. (A), Detrital zircons from Soebi Blanco conglomerate matrix; (B), Zircon ages from metamorphic clasts (C), detrital zircons from late Cretaceous Etpana Formation in Guajira Peninsula (Weber et al., 2010); (D), detrital zircons from late Cretaceous Santa Marta San Lorenzo schists (Cardona et al., 2010a); (E), detrital zircons from late Cretaceous Knip Group (Wrigth and Wyld, 2010); (F), overlap and similarity values.

  16. Continental margin radiography from a potential field and sediment thickness standpoint: the Iberian Atlantic Margin

    Energy Technology Data Exchange (ETDEWEB)

    Catalan, M.; Martos, Y. M.; Martin-Davila, J.; Munoz-Martin, A.; Carbo, A.; Druet, M.


    This study reviews the state of knowledge in the Iberian Atlantic margin. In order to do this, the margin has been divided into three provinces: the Galicia margin, the southern Iberian abyssal plain, and the Tagus abyssal plain. We have used potential field and sediment thickness data. This has allowed us to study the crust, setting limits for the continental crust domain, and the amplitude of the so-called ocean-continent transition, whose end marks the beginning of the oceanic crust. The study shows the continental crust in the Galician margin to be the widest, about 210 km in length, whilst the ocean-continent transition varies slightly in this province: between 65 km wide in the south and 56 km wide in the north. This result shows up some differences with the hypothesis of other authors. The situation in the southern Iberian abyssal plain is nearly the opposite. Its continental crust extends approximately 60 km, whilst the ocean-continent transition zone is 185 km long. The Tagus abyssal plain study shows a faster morphological evolution than the others, according with the amount of crustal thinning β, the ocean-continent transition domain spanning 100 km. These results support a transitional intermediate character for almost the whole Tagus plain, in contrary to what other authors have stated. (Author)

  17. Soil Moisture/ Tree Water Status Dynamics in Mid-Latitude Montane Forest, Southern Sierra Critical Zone Observatory, CA (United States)

    Hartsough, P. C.; Malazian, A.; Meadows, M. W.; Roudneva, K.; Storch, J.; Bales, R. C.; Hopmans, J. W.


    As part of an effort to understand the root-water-nutrient interactions in the multi-dimensional soil/vegetation system surrounding large trees, in August 2008 we instrumented a mature white fir (Abies concolor) and the surrounding soil to better define the water balance in a single tree. In July 2010, we instrumented a second tree, a Ponderosa pine (Pinus ponderosa) in shallower soils on a drier, exposed slope. The trees are located in a mixed-conifer forest at an elevation of 2000m in the Southern Sierra Critical Zone Observatory. The deployment of more than 250 sensors to measure temperature, volumetric water content, matric potential, and snow depth surrounding the two trees complements sap-flow measurements in the trunk and stem-water-potential measurements in the canopy to capture the seasonal cycles of soil wetting and drying. We show here the results of a multi-year deployment of soil moisture sensors as critical integrators of hydrologic/ biotic interaction in a forested catchment. Sensor networks such as deployed here are a valuable tool in closing the water budget in dynamic forested catchments. While the exchange of energy, water and carbon is continuous, the pertinent fluxes are strongly heterogeneous in both space and time. Thus, the prediction of the behavior of the system across multiple scales constitutes a major challenge.

  18. The TESS-HERMES survey data release 1: high-resolution spectroscopy of the TESS southern continuous viewing zone (United States)

    Sharma, Sanjib; Stello, Dennis; Buder, Sven; Kos, Janez; Bland-Hawthorn, Joss; Asplund, Martin; Duong, Ly; Lin, Jane; Lind, Karin; Ness, Melissa; Huber, Daniel; Zwitter, Tomaz; Traven, Gregor; Hon, Marc; Kafle, Prajwal R.; Khanna, Shourya; Saddon, Hafiz; Anguiano, Borja; Casey, Andrew R.; Freeman, Ken; Martell, Sarah; De Silva, Gayandhi M.; Simpson, Jeffrey D.; Wittenmyer, Rob A.; Zucker, Daniel B.


    The Transiting Exoplanet Survey Satellite (TESS) will provide high-precision time series photometry for millions of stars with at least a half-hour cadence. Of particular interest are the circular regions of 12° radius centred around the ecliptic poles that will be observed continuously for a full year. Spectroscopic stellar parameters are desirable to characterize and select suitable targets for TESS, whether they are focused on exploring exoplanets, stellar astrophysics or Galactic archaeology. Here, we present spectroscopic stellar parameters (Teff, log g, [Fe/H], v sin i, vmicro) for about 16 000 dwarf and subgiant stars in TESS' southern continuous viewing zone. For almost all the stars, we also present Bayesian estimates of stellar properties including distance, extinction, mass, radius and age using theoretical isochrones. Stellar surface gravity and radius are made available for an additional set of roughly 8500 red giants. All our target stars are in the range 10, or at Mikulski Archive for Space Telescopes (MAST).

  19. A new prozostrodontian cynodont (Therapsida from the Late Triassic Riograndia Assemblage Zone (Santa Maria Supersequence of Southern Brazil

    Directory of Open Access Journals (Sweden)



    Full Text Available We report here on a new prozostrodontian cynodont, Botucaraitherium belarminoi gen. et sp. nov., from the Late Triassic Riograndia Assemblage Zone (AZ of the Candelária Sequence (Santa Maria Supersequence, collected in the Botucaraí Hill Site, Candelária Municipality, state of Rio Grande do Sul, Brazil. The new taxon is based on a single specimen (holotype MMACR-PV-003-T which includes the left lower jaw, without postdentary bones, bearing the root of the last incisor, canine and four postcanines plus one partial crown inside the dentary, not erupted, and two maxillary fragments, one with a broken canine and another with one postcanine. The features of the lower jaw and lower/upper postcanines resemble those of the prozostrodontians Prozostrodon brasiliensis from the older Hyperodapedon AZ and Brasilodon quadrangularis and Brasilitherium riograndensis from the same Riograndia AZ. The inclusion of Botucaraitherium within a broad phylogenetic analysis, positioned it as a more derived taxon than tritylodontids, being the sister-taxon of Brasilodon, Brasilitherium plus Mammaliaformes. Although the new taxon is based on few cranial elements, it represents a additional faunal component of the Triassic Riograndia AZ of southern Brazil, in which small-sized derived non-mammaliaform cynodonts, closely related to the origin of mammaliaforms, were ecologically well succeed and taxonomically diverse.

  20. The Importance of Southern Hemisphere CZOs for Evaluating Spatial Patterns of Chemical Structure in the Critical Zone and Assisting Human Development (United States)

    Chadwick, O.


    The US Critical Zone Exploration Network (CZEN) is a network of sites designed to provide a better understanding of the integrated Earth surface system. The capacity of the critical zone to withstand perturbations, whether driven by climate, land use change, or spread of invasive species, depends on its chemical composition and physical state, which in turn depends on the time evolution of the critical zone. Many temperate and/or tectonically active critical zones contain a relatively short history due to rapid erosion but tectonically quiescent, tropical regions of the planet contain much longer records that need to be understood to cover the full suite of critical zone processes. Southern Hemisphere Critical Zone Observatories such as those proposed for Kruger National Park (KNP) in South Africa and for portions of the Yilgarn Craton in Western Australa will allow us to extend our temporal understanding of development of spatial heterogeneity in the chemical and physical structure of the critical zone. In addition to considering Earth and climate boundary conditions, these sites incorporate the roles that humans play in driving critical zone processes. For instance along the edges of KNP there is strong evidence of soil erosions due to periurbanization and small-scale agriculture. The existence of KNP provides an important contrast between a "natural" and "human-dominated" landscape that can be exploited to evaluate human impacts on critical zone resources and to develop targeted mitigation strategies. Western Australia has an exploitive economy that relies on large-scale agriculture and mineral extraction, both are intensive users of water which is scarce. The proposed CZO there will be partly focused on managing water under intense economic pressures. It is evident that if funding can be found for these sites they will enhance both critical zone science and practical applied science.

  1. Chronic Exposure to Malaria Is Associated with Inhibitory and Activation Markers on Atypical Memory B Cells and Marginal Zone-Like B Cells

    Directory of Open Access Journals (Sweden)

    Itziar Ubillos


    Full Text Available In persistent infections that are accompanied by chronic immune activation, such as human immunodeficiency virus, hepatitis C virus, and malaria, there is an increased frequency of a phenotypically distinct subset of memory B cells lacking the classic memory marker CD27 and showing a reduced capacity to produce antibodies. However, critical knowledge gaps remain on specific B cell changes and immune adaptation in chronic infections. We hypothesized that expansion of atypical memory B cells (aMBCs and reduction of activated peripheral marginal zone (MZ-like B cells in constantly exposed individuals might be accompanied by phenotypic changes that would confer a tolerogenic profile, helping to establish tolerance to infections. To better understand malaria-associated phenotypic abnormalities on B cells, we analyzed peripheral blood mononuclear cells from 55 pregnant women living in a malaria-endemic area of Papua Nueva Guinea and 9 Spanish malaria-naïve individuals using four 11-color flow cytometry panels. We assessed the expression of markers of B cell specificity (IgG and IgM, activation (CD40, CD80, CD86, b220, TACI, and CD150, inhibition (PD1, CD95, and CD71, and migration (CCR3, CXCR3, and CD62l. We found higher frequencies of active and resting aMBC and marked reduction of MZ-like B cells, although changes in absolute cell counts could not be assessed. Highly exposed women had higher PD1+-, CD95+-, CD40+-, CD71+-, and CD80+-activated aMBC frequencies than non-exposed subjects. Malaria exposure increased frequencies of b220 and proapoptotic markers PD1 and CD95, and decreased expression of the activation marker TACI on MZ-like B cells. The increased frequencies of inhibitory and apoptotic markers on activated aMBCs and MZ-like B cells in malaria-exposed adults suggest an immune-homeostatic mechanism for maintaining B cell development and function while simultaneously downregulating hyperreactive B cells. This mechanism would keep the B cell

  2. Mapping and assessing variability in the Antarctic marginal ice zone, pack ice and coastal polynyas in two sea ice algorithms with implications on breeding success of snow petrels (United States)

    Stroeve, Julienne C.; Jenouvrier, Stephanie; Campbell, G. Garrett; Barbraud, Christophe; Delord, Karine


    Sea ice variability within the marginal ice zone (MIZ) and polynyas plays an important role for phytoplankton productivity and krill abundance. Therefore, mapping their spatial extent as well as seasonal and interannual variability is essential for understanding how current and future changes in these biologically active regions may impact the Antarctic marine ecosystem. Knowledge of the distribution of MIZ, consolidated pack ice and coastal polynyas in the total Antarctic sea ice cover may also help to shed light on the factors contributing towards recent expansion of the Antarctic ice cover in some regions and contraction in others. The long-term passive microwave satellite data record provides the longest and most consistent record for assessing the proportion of the sea ice cover that is covered by each of these ice categories. However, estimates of the amount of MIZ, consolidated pack ice and polynyas depend strongly on which sea ice algorithm is used. This study uses two popular passive microwave sea ice algorithms, the NASA Team and Bootstrap, and applies the same thresholds to the sea ice concentrations to evaluate the distribution and variability in the MIZ, the consolidated pack ice and coastal polynyas. Results reveal that the seasonal cycle in the MIZ and pack ice is generally similar between both algorithms, yet the NASA Team algorithm has on average twice the MIZ and half the consolidated pack ice area as the Bootstrap algorithm. Trends also differ, with the Bootstrap algorithm suggesting statistically significant trends towards increased pack ice area and no statistically significant trends in the MIZ. The NASA Team algorithm on the other hand indicates statistically significant positive trends in the MIZ during spring. Potential coastal polynya area and amount of broken ice within the consolidated ice pack are also larger in the NASA Team algorithm. The timing of maximum polynya area may differ by as much as 5 months between algorithms. These

  3. [Marginalization and health. Introduction]. (United States)

    Yunes, J


    The relationship between marginalization and health is clear. In Mexico, for example, life expectancy is 53 years for the poorest population sectors and 20 years more for the wealthiest. Infant mortality in poor Colombian families is twice that of wealthier families, and one-third of developing countries the rural population is only half as likely as the urban to have access to health services. Women in the Southern hemisphere are 12 times likelier than those in the Northern to die of maternal causes. The most important step in arriving at a solution to the inequity may be to analyze in depth the relationship between marginality and health. Marginality may be defined as the lack of participation of individuals or groups in certain key phases of societal life, such as production, consumption, or political decision making. Marginality came to be viewed as a social problem only with recognition of the rights of all individuals to participate in available social goods. Marginality is always relative, and marginal groups exist because central groups determine the criteria for inclusion in the marginal and central groups. Marginality thus always refers to a concrete society at a specific historical moment. Marginal groups may be of various types. At present, marginal groups include women, rural populations, people with AIDS or mental illness or certain other health conditions, refugees, ethnic or religious groups, homosexuals, and the poor, who are the largest group of marginal persons in the world. Even in developed countries, 100-200 million persons live below the poverty line. Latin America is struggling to emerge from its marginal status in the world. The economic crisis of the 1980s increased poverty in the region, and 40% are not considered impoverished. Latin America is a clear example of the relationship between marginality and health. Its epidemiologic profile is intimately related to nutrition, availability of potable water, housing, and environmental

  4. The seasonal succession of zooplankton in the Southern Ocean south of Australia, part I: The seasonal ice zone (United States)

    Hunt, Brian P. V.; Hosie, Graham W.


    Between November 2001 and March 2002 an Australian/Japanese collaborative study completed six passes of a transect line in the Seasonal-Ice Zone (south of 62°S) along 140°E. Zooplankton samples were collected with a NORPAC net on 22-28 November, and a Continuous Plankton Recorder on 10-15 January, 11-12 February, 19-22 February, 25-26 February, and 10-11 March. Zooplankton densities were lowest on 22-28 November (ave=61 individuals (ind) m -3), when almost the entire transect was covered by sea ice. By 10-15 January sea surface temperature had increased by ˜2 °C across the transect line, and the study area was ice-free. Total zooplankton abundance had increased to maximum levels for the season (ave=1301 ind m -3; max=1979 ind m -3), dominated by a "Peak Community" comprising Oithona similis, Ctenocalanus citer, Clausocalanus laticeps, foraminiferans, Limacina spp., appendicularians, Rhincalanus gigas and large calanoid copepodites (C1-3). Total densities declined on each subsequent transect, returning to an average of 169 ind m -3 on 10-11 March. The seasonal density decline was due to the decline in densities of "Peak Community" taxa, but coincided with the rise of Euphausia superba larvae into the surface waters, increased densities of Salpa thompsoni, and an increased contribution of C4 to adult stages to the populations of Calanoides acutus, Calanus propinquus and Calanus simillimus. The seasonal community succession appeared to be influenced by the low sea ice extent and southward projection of the ACC in this region. The relatively warm ACC waters, together with low krill biomass, favoured high densities of small grazers during the January/February bloom conditions. The persistence of relatively warm surface waters in March and the seasonal decrease in chlorophyll a biomass provided favorable conditions for salps, which were able to penetrate south of the Southern Boundary.

  5. Temporal variability and coherence of euphotic zone bacterial communities over a decade in the Southern California Bight. (United States)

    Chow, Cheryl-Emiliane T; Sachdeva, Rohan; Cram, Jacob A; Steele, Joshua A; Needham, David M; Patel, Anand; Parada, Alma E; Fuhrman, Jed A


    Time-series are critical to understanding long-term natural variability in the oceans. Bacterial communities in the euphotic zone were investigated for over a decade at the San Pedro Ocean Time-series station (SPOT) off southern California. Community composition was assessed by Automated Ribosomal Intergenic Spacer Analysis (ARISA) and coupled with measurements of oceanographic parameters for the surface ocean (0-5 m) and deep chlorophyll maximum (DCM, average depth ≈ 30 m). SAR11 and cyanobacterial ecotypes comprised typically more than one-third of the measured community; diversity within both was temporally variable, although a few operational taxonomic units (OTUs) were consistently more abundant. Persistent OTUs, mostly Alphaproteobacteria (SAR11 clade), Actinobacteria and Flavobacteria, tended to be abundant, in contrast to many rarer yet intermittent and ephemeral OTUs. Association networks revealed potential niches for key OTUs from SAR11, cyanobacteria, SAR86 and other common clades on the basis of robust correlations. Resilience was evident by the average communities drifting only slightly as years passed. Average Bray-Curtis similarity between any pair of dates was ≈ 40%, with a slight decrease over the decade and obvious near-surface seasonality; communities 8-10 years apart were slightly more different than those 1-4 years apart with the highest rate of change at 0-5 m between communities <4 years apart. The surface exhibited more pronounced seasonality than the DCM. Inter-depth Bray-Curtis similarities repeatedly decreased as the water column stratified each summer. Environmental factors were better predictors of shifts in community composition than months or elapsed time alone; yet, the best predictor was community composition at the other depth (that is, 0-5 m versus DCM).

  6. Faulting, volcanism, and basin development along the western margin of the southern San Luis Basin segment of the Rio Grande rift, New Mexico and Colorado (United States)

    Turner, K. J.; Thompson, R. A.; Cosca, M. A.; Drenth, B.; Lee, J.; Budahn, J. R.


    The San Luis Basin segment of the northern Rio Grande rift, straddling the Colorado-New Mexico border, is an asymmetrical graben where the major basin-bounding fault is on the east side. In contrast, the west side is a basin-directed dip slope surface cut by north to northwest trending faults with predominantly down-to-southwest displacement. Around 26 Ma, initial rift-related faulting formed broad, shallow basins coincident with basaltic volcanism of the Hinsdale Formation. Later episodes of rifting produced deep and narrow sub-basins generally along the eastern boundary. Basin-fill deposits along the western margin are generally thin. However, in the northern Tusas Mountains, gravity data identifies a small, yet deep, sub-basin that may contain 750 m of basin-filling Los Pinos Formation based on thickness projections derived from mapping. The Los Pinos Formation is overlain by early rift-related Hinsdale Formation basalt flows indicating this sub-basin formed as part of early rifting; the sub-basin may be a southern extension of the Monte Vista graben to the north. The stratigraphic section along the western boundary includes Precambrian basement up to volcanic rocks of the Taos Plateau volcanic field (~5-2Ma). Dips on the early-rift Miocene to Oligocene Hinsdale Formation lavas (3-5 degrees) reflect the cumulative eastward tilting corresponding to continued basin subsidence. Shallower dips (1-2 degrees) on early Pliocene volcanic rocks suggest continued subsidence up to about 3 Ma, or younger. Down-to-southwest faults accommodating eastward tilting are mostly in areas west of Pliocene volcanic rocks; individual faults offset Hinsdale Formation and older rocks by up to 200 m. The few observed faults in the Pliocene volcanic rocks have minor offset. Numerous volcanic vents are in close proximity to the faults along the western boundary. Volcanoes are commonly low to medium relief shield volcanoes with basaltic andesite composition capped by late stage cinder cones

  7. Marginal Models

    CERN Document Server

    Bergsma, Wicher; Hagenaars, Jacques A


    Presents an overview of the basic principles of marginal modeling and offers a range of possible applications. This book includes many real world examples, explains the types of research questions for which marginal modeling is useful, and provides a description of how to apply marginal models for a great diversity of research questions.

  8. Semi-automatic mapping of fault rocks on a Digital Outcrop Model, Gole Larghe Fault Zone (Southern Alps, Italy) (United States)

    Mittempergher, Silvia; Vho, Alice; Bistacchi, Andrea


    A quantitative analysis of fault-rock distribution in outcrops of exhumed fault zones is of fundamental importance for studies of fault zone architecture, fault and earthquake mechanics, and fluid circulation. We present a semi-automatic workflow for fault-rock mapping on a Digital Outcrop Model (DOM), developed on the Gole Larghe Fault Zone (GLFZ), a well exposed strike-slip fault in the Adamello batholith (Italian Southern Alps). The GLFZ has been exhumed from ca. 8-10 km depth, and consists of hundreds of individual seismogenic slip surfaces lined by green cataclasites (crushed wall rocks cemented by the hydrothermal epidote and K-feldspar) and black pseudotachylytes (solidified frictional melts, considered as a marker for seismic slip). A digital model of selected outcrop exposures was reconstructed with photogrammetric techniques, using a large number of high resolution digital photographs processed with VisualSFM software. The resulting DOM has a resolution up to 0.2 mm/pixel. Most of the outcrop was imaged using images each one covering a 1 x 1 m2 area, while selected structural features, such as sidewall ripouts or stepovers, were covered with higher-resolution images covering 30 x 40 cm2 areas.Image processing algorithms were preliminarily tested using the ImageJ-Fiji package, then a workflow in Matlab was developed to process a large collection of images sequentially. Particularly in detailed 30 x 40 cm images, cataclasites and hydrothermal veins were successfully identified using spectral analysis in RGB and HSV color spaces. This allows mapping the network of cataclasites and veins which provided the pathway for hydrothermal fluid circulation, and also the volume of mineralization, since we are able to measure the thickness of cataclasites and veins on the outcrop surface. The spectral signature of pseudotachylyte veins is indistinguishable from that of biotite grains in the wall rock (tonalite), so we tested morphological analysis tools to discriminate

  9. Sedimentary architecture and palaeogeography of lower Slochteren Aeolian cycles from the Rotliegend desert-lake margin (Permian), the Markham area, Southern North Sea

    NARCIS (Netherlands)

    Belt, F.J.G. van den; Hulten, F.F.N. van


    The Rotliegend gas play in the Southern Permian Basin has yielded over 200 gas fields in the Netherlands; they are found in an E-W fairway along the southern flank of the basin. Sandstones generally pinch out basinward, but localized, isolated sands are present north of the main fairway. The

  10. A quasi-linear structure of the southern margin of Eurasia prior to the India-Asia collision: First paleomagnetic constraints from Upper Cretaceous volcanic rocks near the western syntaxis of Tibet (United States)

    Yi, Zhiyu; Huang, Baochun; Yang, Liekun; Tang, Xiangde; Yan, Yonggang; Qiao, Qingqing; Zhao, Jie; Chen, Liwei


    We report the first combined geochronologic and paleomagnetic study of volcanic rocks from the Shiquanhe and Yare Basins at the westernmost Lhasa Terrane, which aims to provide an accurate constraint on the shape and paleoposition of the southern margin of Asia prior to the India-Asia collision. Three new 40Ar/39Ar ages of 92.5 ± 2.9 Ma, 92.4 ± 0.9 Ma, and 79.6 ± 0.7 Ma determined by fresh matrix or feldspar from lava flows suggest a Late Cretaceous age for the investigated units. Characteristic remanent magnetizations have been successfully isolated from 38 sites which pass positive fold and/or reversal, conglomerate tests and are hence interpreted as primary in origin. The two paleopoles obtained from Yare and Shiquanhe yield consistent paleolatitudes of 13.6°N ± 9.6°N and 14.2°N ± 2.7°N, respectively (for a reference site of 31.5°N, 80°E), indicating that the southern margin of Asia near the western syntaxis was located far south during the Late Cretaceous time. A reconstruction of the Lhasa Terrane in the frame of Eurasia with paleomagnetic data obtained from its western and eastern parts indicates that the southern margin of Eurasia probably had a quasi-linear orientation prior to the collision formerly trending approximately 315°E. This is compatible with the shape of the Neo-Tethys slab observed from seismic tomographic studies. Our findings provide a solid basis for evaluating Cenozoic crustal shortening in the Asian interior and the size of Greater India near the western syntaxis.

  11. Inter-species hybridization among Neotropical cats of the genus Leopardus, and evidence for an introgressive hybrid zone between L. geoffroyi and L. tigrinus in southern Brazil. (United States)

    Trigo, T C; Freitas, T R O; Kunzler, G; Cardoso, L; Silva, J C R; Johnson, W E; O'Brien, S J; Bonatto, S L; Eizirik, E


    Natural hybrid zones between distinct species have been reported for many taxa, but so far, few examples involve carnivores or Neotropical mammals in general. In this study, we employed mitochondrial DNA (mtDNA) sequences and nine microsatellite loci to identify and characterize a hybrid zone between two Neotropical felids, Leopardus geoffroyi and L. tigrinus, both of which are well-established species having diverged from each other c. 1 million years ago. These two felids are mostly allopatric throughout their ranges in South America, with a narrow contact zone that includes southern Brazil. We present strong evidence for the occurrence of hybridization between these species and identify at least 14 individuals (most of them originating from the geographical contact zone) exhibiting signs of interspecific genomic introgression. The genetic structure of Brazilian L. tigrinus populations seems to be affected by this introgression process, showing a gradient of differentiation from L. geoffroyi correlated with distance from the contact zone. We also corroborate and extend previous findings of hybridization between L. tigrinus and a third related felid, L. colocolo, leading to an unusual situation for a mammal, in which the former species contains introgressed mtDNA lineages from two distinct taxa in addition to its own.

  12. Phosphorites from the Oman Margin, ODP Leg 117

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Lamboy, M.

    Pliocene - Early Pleistocene sediments is favoured by the deepening of the Oman margin which took place during the Late Pliocene and the establishment of an oxygen minimum zone at about this time. Unlike the Peru margin phosphorites, the Oman margin...

  13. Epidemiology of intestinal helminthiasis among school children with emphasis on Schistosoma mansoni infection in Wolaita zone, Southern Ethiopia

    Directory of Open Access Journals (Sweden)

    Bereket Alemayehu


    Full Text Available Abstract Background Intestinal helminth infections are major parasitic diseases causing public health problems in Ethiopia. Although the epidemiology of these infections are well documented in Ethiopia, new transmission foci for schistosomiasis are being reported in different parts of the country. The objective of this study was to assess the prevalence of Schistosoma mansoni and other intestinal helminth infections among school children and determine the endemicity of schistosomiasis in Wolaita Zone, southern Ethiopia. Methods Cross-sectional parasitological and malacological surveys were conducted by collecting stool samples for microscopic examination and snails for intermediate host identification. Stool samples were collected from 503 children and processed for microscopic examination using Kato-Katz and formalin-ether concentration methods. Snails collected from aquatic environments in the study area were identified to species level and Biomphalaria pfeifferi snails, the intermediate host of S. mansoni,, were individually exposed to artificial light in order to induce cercariae shedding. Cercariae shed from snails were used to infect laboratory-bred Swiss albino mice in order to identify the schistosome to species level. Results The overall prevalence of intestinal helminth infections was 72.2% among school children. S. mansoni infection prevalence was 58.6%. The prevalence and intensity of S. mansoni infections varied among schools and sex of children. Swimming was the only factor reported to be significantly associated with S. mansoni infection (AOR = 2.954, 95% CI:1.962-4.449. Other intestinal helminth species identified were hookworms (27.6%, Ascaris lumbricoides (8.7%, E. vermicularis (2.8%, Taenia species (2.6%, T. trichiura (1.2% and H. nana (0.6%. Only B. pfeifferi snails collected from streams shed schistosome cercariae and 792 adult S. mansoni worms were harvested from mice exposed to cercariae shed from B. pfeifferi on the 6th

  14. Estimating CH4 emission from paddy managed soils in southern guinea savanna zone of Nigeria using an integrated approach (United States)

    Akpeokhai, Agatha; Menz, Gunter; Thonfeld, Frank; Akinluyi, Francis


    ESTIMATING CH4 EMISSION FROM PADDY MANAGED SOILS IN SOUTHERN GUINEA SAVANNA ZONE OF NIGERIA USING AN INTEGRATED APPROACH Akpeokhai Agatha 1, Menz Gunter 1, Thonfeld Frank 1, Akinluyi Francis 2 1 Remote Sensing Research Group (RSRG), Geography Institute, University of Bonn, Germany. 2 Department Remote Sensing and Geo-Science Information System, School of Earth and Mineral Science, Federal University of Technology, Akure Nigeria. Methane is one of the most important greenhouse gases as it has the second greatest climate forcing potential. Paddy fields have been identified to be sources of methane and Nigerian paddies are not left out. In Nigeria, the guinea savanna region is regarded as the bread basket of the nation and this area is one of the major rice producing regions in Nigeria. Its location in the food basket region of the country makes this part a very important study site. However, since Nigerian paddies contribute to methane emission by how much do these paddies contribute to the emissions? Also, so far, there limited studies on methane from rice fields in West Africa thus making this study a very important start off point. To answer this huge question, methane emission will be estimated using an integrated approach in the North Central part of Nigeria. Land use change cultivated to rice was analysed using Remote sensing techniques to determine the changes in land cultivated to rice. Methane emission from these identified rice fields will be estimated using the IPCC Tier 1 set of equations. First relevant indices (Normalized Differential Moisture Index, Normalized Differential Wetness Index and Rice Growth Vegetation Index) were generated to aid classification of rice fields using LANDSAT data from the USGS. Next the LANDSAT datasets were analyzed for land use change cultivated to rice from 1990 to 2014 to generate rice field maps. ERDAS Imagine, ARCGIS and ENVI tools were used to meet these spatial needs. Methane emissions from this region will be

  15. Differentiation of Secular and Postseismic Deformation in the Mojave Shear Zone in Southern California and Inference of Lithospheric Rheology (United States)

    Shen, Z.; Liu, S.; Burgmann, R.


    The 1992 Mw 7.3 Landers and 1999 Mw7.1 Hector Mine earthquakes struck the Eastern California Shear Zone (ECSZ) in the Mojave Desert, Southern California. Coseismic and postseismic deformation from these events affect efforts to use Global Positioning System (GPS) observations collected since these events to establish a secular surface velocity field, especially in the near field of the coseismic ruptures. We devise block motion models constrained by both historical pre-Landers triangulation and trilateration observations and post-Landers GPS measurements to recover the secular deformation field and differentiate the postseismic transients in the Mojave region. Postseismic transients are found to remain in various "interseismic" GPS velocity solutions in the form of 2-3 mm/yr excess right-lateral shear across the Landers and Hector Mine coseismic ruptures [Liu et al., 2015 JGR]. Postseismic GPS time series differentiated from the secular velocity field reveal enduring late-stage transient motions in the near field of the coseismic ruptures. Using the postseismic time series data as model constraints, we develop postseismic deformation model invoking afterlip on faults and viscoelastic relaxation in the lower crust and upper mantle. A Burgers body material and a Maxwell material are assumed for the lower crust and upper mantle respectively. Our preliminary modeling result, constrained using GPS time series data from the SCEC Crustal Motion Map 4.0 (covering the time period of 1992-2004), reveals that both the long-term viscosities for the lower crust and upper mantle are on the order of e+19 Pa-s. This finding differs significantly from the "Crème Brulee" model predictions about the rheological structure of the lower crust and upper mantle, in which the lower crust has a substantially higher viscosity. We are incorporating more GPS time series data into our model, particularly the ones from continuous sites of the Plate Boundary Observatory network with post-2004

  16. Epidemiology of intestinal helminthiasis among school children with emphasis on Schistosoma mansoni infection in Wolaita zone, Southern Ethiopia. (United States)

    Alemayehu, Bereket; Tomass, Zewdneh; Wadilo, Fiseha; Leja, Dawit; Liang, Song; Erko, Berhanu


    Intestinal helminth infections are major parasitic diseases causing public health problems in Ethiopia. Although the epidemiology of these infections are well documented in Ethiopia, new transmission foci for schistosomiasis are being reported in different parts of the country. The objective of this study was to assess the prevalence of Schistosoma mansoni and other intestinal helminth infections among school children and determine the endemicity of schistosomiasis in Wolaita Zone, southern Ethiopia. Cross-sectional parasitological and malacological surveys were conducted by collecting stool samples for microscopic examination and snails for intermediate host identification. Stool samples were collected from 503 children and processed for microscopic examination using Kato-Katz and formalin-ether concentration methods. Snails collected from aquatic environments in the study area were identified to species level and Biomphalaria pfeifferi snails, the intermediate host of S. mansoni,, were individually exposed to artificial light in order to induce cercariae shedding. Cercariae shed from snails were used to infect laboratory-bred Swiss albino mice in order to identify the schistosome to species level. The overall prevalence of intestinal helminth infections was 72.2% among school children. S. mansoni infection prevalence was 58.6%. The prevalence and intensity of S. mansoni infections varied among schools and sex of children. Swimming was the only factor reported to be significantly associated with S. mansoni infection (AOR = 2.954, 95% CI:1.962-4.449). Other intestinal helminth species identified were hookworms (27.6%), Ascaris lumbricoides (8.7%), E. vermicularis (2.8%), Taenia species (2.6%), T. trichiura (1.2%) and H. nana (0.6%). Only B. pfeifferi snails collected from streams shed schistosome cercariae and 792 adult S. mansoni worms were harvested from mice exposed to cercariae shed from B. pfeifferi on the 6th week post-exposure. The present study found high

  17. Young volcanoes in the Chilean Southern Volcanic Zone: A statistical approach to eruption prediction based on time series (United States)

    Dzierma, Y.; Wehrmann, H.


    Forecasting volcanic activity has long been an aim of applied volcanology with regard to mitigating consequences of volcanic eruptions. Effective disaster management requires both information on expected physical eruption behaviour such as types and magnitudes of eruptions as typical for the individual volcano, usually reconstructed from deposits of past eruptions, and the likelihood that a new eruption will occur within a given time. Here we apply a statistical procedure to provide a probability estimate for future eruptions based on eruption time series, and discuss the limitations of this approach. The statistical investigation encompasses a series of young volcanoes of the Chilean Southern Volcanic Zone. Most of the volcanoes considered have been active in historical times, in addition to several volcanoes with a longer eruption record from Late-Pleistocene to Holocene. Furthermore, eruption rates of neighbouring volcanoes are compared with the aim to reveal possible regional relations, potentially resulting from local to medium-scale tectonic dynamics. One special focus is directed to the two currently most active volcanoes of South America, Llaima and Villarrica, whose eruption records comprise about 50 historical eruptions over the past centuries. These two front volcanoes are considered together with Lanín Volcano, situated in the back-arc of Villarrica, for which the analysis is based on eight eruptions in the past 10 ka. For Llaima and Villarrica, affirmed tests for independence of the repose times between successive eruptions permit to assume Poisson processes; which is hampered for Lanín because of the more limited availability of documented eruptions. The assumption of stationarity reaches varying degrees of confidence depending on the time interval considered, ameliorating towards the more recent and hence probably more complete eruption record. With these pre-requisites of the time series, several distribution functions are fit and the goodness of

  18. Linking deformation and chemical re-equilibration: new results from the Cretaceous Vinschgau shear zone (Southern Tyrol, Italy) (United States)

    Eberlei, Tobias; Habler, Gerlinde; Grasemann, Bernhard; Abart, Rainer


    The Austroalpine Matsch Unit in the European Eastern Alps preserves evidence for at least three tectonometamorphic cycles, including a Variscan amphibolite-facies metamorphism, a Permian high-T/low-P event related to the intrusion of pegmatites and a Cretaceous metamorphism at the greenschist to amphibolite-facies transition. The southern tectonic boundary of the Matsch unit is formed by the about 2 km thick Vinschgau shear zone, which was active during the Cretaceous and involves metapelites, orthogneisses and metapegmatites (Schmid & Haas 1989). A characteristic mylonitic foliation with an E-W trending stretching lineation, S-C and S-C-Ć fabrics with general top W non-coaxial shear kinematics developed. Remarkable strain-gradients occur at the cm- to m-scale, partly associated with lithological heterogeneities. In this contribution we focus on the relationship between deformation and microstructural- and chemical re-equilibration of white mica and feldspar in the Permian metapegmatites. Based on detailed structural characterization during field work, we used optical microscopy and scanning electron microscopy (SEM) as well as electron backscatter diffraction (EBSD) for microstructural and microtextural characterization. An electron microprobe (EPMA) was used for analyzing the major element compositions of microstructurally different phase generations. In the Permian metapegmatites metamorphic white mica, plagioclase feldspar (ab87 - ab99) and K-feldspar replaced the primary pegmatite assemblages. Magmatic white mica with near-end member composition of muscovite is strongly deformed, showing kinks, undulose extinction and cracks. A new fine-grained white mica generation with elevated celadonite-component (SiIV = 3.05-3.25 cations/11O) not only predominates the mylonitic foliation and compressional quadrants of mm-sized albite and muscovite clasts but also compositionally altered zones within primary magmatic white mica along kink planes and cleavage planes. The

  19. IODP expedition 334: An investigation of the sedimentary record, fluid flow and state of stress on top of the seismogenic zone of an erosive subduction margin

    Digital Repository Service at National Institute of Oceanography (India)

    Vannucchi, P.; Ujiie, K.; Stroncik, N.; IODP Exp. 334 Scientific Party; Yatheesh, V.

    The Costa Rica Seismogenesis Project (CRISP) is an experiment to understand the processes that control nucleation and seismic rupture of large earthquakes at erosional subduction zones. Integrated Ocean Drililng Program (IODP) Expedition 334 by R...

  20. Petrology and ⁴⁰Ar/3⁹Ar-chronology of metavolcanic rocks from the Northern Phyllite Zone (Southern Hunsrück and Taunus Mountains, Germany): insights into a late Variscan ductile shear zone. (United States)

    Fladt, Matthias; Soder, Christian; Schwarz, Winfried; Trieloff, Mario


    The Northern Phyllite Zone (NPZ) is a low-grade mylonitic shear zone between the high-grade rocks of the Mid-German Crystalline Zone and the very low-grade rocks of the Rhenohercynian Zone of the Variscan orogen. The NPZ comprises low-grade metasedimentary and metavolcanic rocks. Basaltic, intermediate and rhyolitic metavolcanics from the Soonwald and the Southern Taunus Mountains show the following paragenesis: actinolite + chlorite + epidote + albite + phengite + titanite + quartz ± calcite ± stilpnomelane ± pumpellyite ± aegirine-augite; blue amphibole (winchite) + chlorite + phengite + stilpnomelane + albite + titanite + quartz + magnetite ± epidote ± hematite; quartz + albite + K-feldspar + phengite + chlorite + titanite ± stilpnomelane ± ilmenite ± magnetite ± hematite. Occasionally, relict magmatic phases are present. The foliation strikes SW-NE and dips 60-70° to the NW. Stretching lineations are subhorizontal. P-T-estimations were done on the basis of equilibrium assemblage modelling yielding peak metamorphic conditions of 300-350 °C and 6-6.5 kbar. Thus, burial depths of 20-22 km and a low geothermal gradient of 15-16 °C/km are inferred. ⁴⁰Ar/3⁹Ar-dating of stepwise heated phengite separates (100-200 µm) results in plateau ages of ˜320 Ma. Two of the examined separates show argon diffusive loss ⁴⁰Ar/3⁹Ar-age spectra, which yield a period of argon loss between 145 and 130 Ma. Diffusive argon loss is possibly related to widespread Jurassic-Cretaceous hydrothermal activity in SW Germany. We interpret the Northern Phyllite Zone as a sinistral shear zone documenting prolonged oblique convergence following the peak of the Variscan orogeny between 340-330 Ma until 320 Ma.

  1. Magmatic evolution in the N-Gondwana margin related to the opening of the Rheic Ocean—evidence from the Upper Parautochthon of the Galicia-Trás-os-Montes Zone and from the Central Iberian Zone (NW Iberian Massif) (United States)

    Dias da Silva, Ícaro; Díez Fernández, Rubén; Díez-Montes, Alejandro; González Clavijo, Emilio; Foster, David A.


    LA-MC-ICP-MS U-Pb zircon ages and whole-rock geochemical data obtained from volcanic rocks erupted in the northern margin of Gondwana provide new insights on the polyphase magmatic evolution of the NW Iberian domain during the establishment of passive margin conditions in Lower Paleozoic times. The U-Pb data show crystallization ages of ca. 455 Ma for two calc-alkaline rhyolites sampled in the Upper Parautochthon of the eastern Galicia—Trás-os-Montes Zone (GTMZ) and for an intraplate basalt intruded into Middle Ordovician slates of the autochthonous series of the Central Iberian Zone (CIZ). Together with previous data, the ages obtained reveal a periodic magmatic activity across the northern Gondwana margin during the Lower Paleozoic, which is comparable to that observed in NE Iberia and in other massifs of the Mediterranean realm. Both geochronological and geochemical data reinforce paleontological and stratigraphic evidences for paleogeographic proximity between these domains and contribute to the recognition of extensional-related magmatism along the northern margin of Central Gondwana associated with the opening of the Rheic Ocean.

  2. Evaluation of the effectiveness of riparian zone restoration in the southern Appalachians by assessing soil microbial populations (United States)

    Guanglong Tian; James M. Vose; David C. Coleman; Christopher D. Geron; John T. Walker


    Microbial biomass, nitrifiers and denitrifiers in surface soil (0-10 cm) were quantified in a riparian zone restoration project at Coweeta, North Carolina, USA. Four treatments are included in this study: ( I ) a degraded (+N) riparian zone with continued compaction, vegetation removal, and nutrient addition (mow, roll, and nutrient addition);(2) a degraded (-N)...

  3. Onshore-offshore seismic reflection profiling across the southern margin of the Sea of Japan: back-arc opening, shortening and active strike-slip deformation (United States)

    Sato, Hiroshi; Ishiyama, Tatsuya; Kato, Naoko; Toda, Shigeru; Kawasaki, Shinji; Fujiwara, Akira; Tanaka, Yasuhisa; Abe, Susumu


    M7-class crustal earthquakes of overlying plate in subduction system have tendency to increase before megathrust earthquake events. Due to stress buildup by the upcoming Nankai Trough megathrust earthquake, SW Japan has being seismically active for last 20 years. In terms of the mitigation of earthquake and tsunami hazards, to construct seismogenic source fault models is first step for evaluating the strong ground motions and height of tsunamis. Since 2013, we performed intense seismic profiling in and around the southern part of the Sea of Japan. In 2016, a 180-km-long onshore -offshore seismic survey was carried out across the volcanic arc and back-arc basins (from Kurayoshi to the Yamato basin). Onshore section, CMP seismic reflection data were collected using four vibroseis trucks and fixed 1150 channel recorders. Offshore part we acquired the seismic reflection data using 1950 cu inch air-guns towing a 4-km-long streamer cable. We performed CMP reflection and refraction tomography analysis. Obtained seismic section portrays compressively deformed rifted continental crust and undeformed oceanic back-arc basin, reflecting the rheological features. These basic structures were formed during the opening of the Sea of Japan in early Miocene. The sub-horizontal Pliocene sediments unconformably cover the folded Miocene sediments. The opening and clock-wise rotation of SW Japan has been terminated at 15 Ma and contacted to the young Shikoku basin along the Nankai trough. Northward motion of Philippine Sea plate (PHS) and the high thermal regime in the Shikoku basin produced the strong resistance along the Nankai trough. The main shortening deformation observed in the seismic section has been formed this tectonic event. After the initiation of the subduction along the Nankai trough, the rate of shortening deformation was decreased and the folded strata were covered by sub-horizontal Pliocene sediments. The thrusting trending parallel to the arc has been continued from

  4. Carlsbad, San Onofre, and San Mateo Fault Zones: Possible Right-Lateral Offset Along the Slope-Basin Transition, Offshore Southern California (United States)

    Conrad, J. E.; Dartnell, P.; Sliter, R. W.; Ryan, H. F.; Maier, K. L.; Brothers, D. S.


    Several poorly understood faults are exposed along the mid- and lower slope offshore southern California from Encinitas to San Clemente. From south to north, these faults have been referred to as the Carlsbad, San Onofre, and San Mateo fault zones, which are generally characterized as nearly vertical to steeply east-dipping faults with a reverse slip component. The U.S. Geological Survey collected high-resolution seismic reflection and bathymetric data from 2009-2012 to better characterize these faults. From offshore Encinitas to Oceanside, these data reveal a complex and variable fault zone that structurally controls the slope-basin transition. In this area, the faults show both reverse as well as normal offset, but may also include an unknown amount of strike-slip offset. North of Oceanside, however, faulting shows clear evidence of right-lateral slip, offsetting submarine channels near the base of the slope by approximately 60 m. North of these offset channels, the base of the slope bends about 30° to the west, following the trend of the San Mateo fault zone, but fault strands on strike with those that offset the channels trend obliquely up slope, appearing to merge with the Newport-Inglewood fault zone (NIFZ) on the shelf. These fault strands consist of several en echelon left-stepping segments separated by "pop-up" structures, which imply a significant component of right-lateral offset along this fault zone, and thus may serve to transfer right-lateral slip from faults along the base of the slope to the NIFZ. This fault zone also separates structures associated with the San Mateo fold and thrust belt to the west from undeformed slope sediments to the east. The existence of significant right-lateral slip on faults along the slope and slope-basin transition has implications for assessing seismic hazards associated with the NIFZ, and also provides constraints on possible reverse motion on the hypothesized Oceanside Thrust.

  5. Acute Disruption of Bone Marrow B Lymphopoiesis and Apoptosis of Transitional and Marginal Zone B Cells in the Spleen following a Blood-Stage Plasmodium chabaudi Infection in Mice

    Directory of Open Access Journals (Sweden)

    Viki Bockstal


    Full Text Available B cells and antibodies are essential for the protective immune response against a blood-stage Plasmodium infection. Although extensive research has focused on memory as well as plasma B-cell responses during infection, little is known about how malaria affects B-cell development and splenic maturation into marginal zone B (MZB and follicular B (FoB cells. In this study, we show that acute Plasmodium chabaudi AS infection in C57Bl/6 mice causes severe disruption of B lymphopoiesis in the bone marrow, affecting in particular pro-, pre-, and immature B cells as well as the expression of the bone marrow B-cell retention chemokine CXCL12. In addition, elevated apoptosis of transitional T2 and marginal zone (MZ B cells was observed during and subsequent to the control of the first wave of parasitemia. In contrast, Folllicular (Fo B cells levels were retained in the spleen throughout the infection, suggesting that these are essential for parasite clearance and proper infection control.

  6. Mercury concentration in the sediments as a function of changing climate in coastal zone of Southern Baltic Sea – preliminary results

    Directory of Open Access Journals (Sweden)

    Bełdowska M.


    Full Text Available Mercury, despite of its many uses in industry, is also highly toxic. It is highly neurotoxic, and because of the ability of mercury to penetrate placental barrier, in some countries ban on predatory fish consumption (the main route of mercury into human organism by pregnant women was introduced. There are very little publications describing the consequences of weather anomalies on contaminants cycles. No research was published concerning the reemission of Hg due to climate change in the Southern Baltic Sea. The study area was situated in the coastal zone of the Gulf of Gdansk - the Southern Baltic. Samples of different species of macrophytobenthos were collected once a month during 2006-2012. Samples of Potamogeton pectinatus, sediments and pore waters were collected once a month from February 2011 to January 2012. The climate changes in the moderate latitudes: extension of the fall season, has contributed to stabilization of high concentrations of mercury in pore waters. Lack of ice cover in the coastal zone and simultaneous occurrence of storms had an impact on supply of the organic matter to the sediments and the increased concentration of Hg. More intense burning of fossil fuels in this season favored the increased metal concentration in the atmosphere and consequently an increase of the atmospheric deposition of metals to the sediments. This led to a fourfold increase of the mercury concentration in sediments as compared to fall season.

  7. Range shifts and global warming: ecological responses of Empetrum nigrum. to experimental warming at its northern (high Arctic) and southern (Atlantic) geographical range margin

    NARCIS (Netherlands)

    Buizer, B.; van Bodegom, P.M.; Greve Alsos, I.; Bronken Eidesen, P.; van Breda, J.; de Korte, M.; van Rijckevorsel, J.; Rozema, J.


    Global change is expected to lead to range shifts of plant species. The ecological mechanisms underpinning these shifts are currently not well understood. Here, we compared ecological responses possibly underlying southern range contraction and northern range expansion of Empetrum nigrum, a key

  8. From the passive to the active Neotethyan margin : preliminary insights from the structure of the Crush zone in north-central Zagros (Iran) (United States)

    Agard, P.; Omrani, J.; Jolivet, L.


    Although first-order unknowns still remain (such as the exact timing of the final oceanic closure or the inception of collision, or even the location of the Neotethyan suture zone), the Zagros orogen provides a unique opportunity, within the convergent Alpine system running from Turkey to Oman, to evaluate the interplay between the young (and diachronous along strike) Tertiary collision and earlier subduction/obduction processes. We present a review of existing data together with the results of preliminary observations made across the main Zagros fault (MZF; Kermanshah-Hamadan area), that is across the Crush zone and the internal Sanandaj-Sirjan zone (SSZ). The new cross-section from the Zagros folded belt to the SSZ points to several major tectonic steps taking place at the end of the Cretaceous, during the late Eocene and from the Mio-Pliocene onwards (ca. < 20 Ma), respectively. Observations are in overall agreement with Braud's conclusions (1971) on the structure of the Crush zone, showing that the following units are piled up, from bottom to top: radiolarites, Bisotun 'exotic' limestones, the obducted ophiolite, Eocene volcanics, unconformably lying Miocene deposits and the SSZ proper. However, it is shown that: 1) radiolarites appear to be partly associated to the obducted ophiolites, 2) deformation partitionning is marked in the Bisotun units by a 20 km wide shear band (evidenced by fold patterns along the MZF), and 3) Bisotun units are shown to be boudinaged at the regional scale. The overall deformation style and the lack of HP metamorphism suggest that, unlike for Turkey and Oman, HP rocks are still buried down below the Crush zone and point to a different subduction dynamics. The tectono-metamorphic study of the Jurassic Hamadan phyllites from the SSZ shows that the HT-LP metamorphism related to late Cretaceous granite intrusions (i.e., more or less contemporaneous to the obduction stage) affects rocks metamorphosed earlier, under metamorphic MP

  9. Rangeland dynamics in South Omo Zone of Southern Ethiopia: Assessment of rangeland condition in relation to altitude and Grazing types

    NARCIS (Netherlands)

    Terefe, A.; Ebro, A.; Tessema, Z.K.


    A study was undertaken in Hamer and Benna-Tsemay districts of the Southern Ethiopia with the objective to determine the condition of the rangelands for grazing animals as influenced by altitude and grazing types. The rangelands in each of the study districts were stratified based on altitude and

  10. Radiographic evaluation of marginal bone levels during healing period, adjacent to parallel-screw cylinder implants inserted in the posterior zone of the jaws, placed with flapless surgery. (United States)

    Nickenig, Hans-Joachim; Wichmann, Manfred; Schlegel, Karl Andreas; Nkenke, Emeka; Eitner, Stephan


    The purpose of this study was to compare changes at the marginal bone level adjacent to implants placed with flapless surgery and flap surgery during a stress-free healing period. Seven hundred and eighty-five implants were placed in 417 patients with a flapless approach and 459 implants were placed in 227 patients using flap techniques. The marginal bone level was determined radiographically, using digitized panoramic radiographs, at two time points: at implant placement (baseline) and after the healing period. The median follow-up time was 0.5 years (SD, 1.2; range: 0.3-0.7). Implants placed with flapless surgery had a mean crestal bone loss of 0.5 mm (SD, 0.5; range: -0.7-2.4) and implants placed with flap surgery had a mean bone loss of 0.5 mm (SD, 0.7; range: -2.0-3.0) after healing. Differences in bone level changes between smokers and non-smokers were statistically significant for the flapless group (Pflapless surgery and flap surgery. Appropriate case selection after virtual planning of the implant position and a sound surgical protocol is necessary for flapless surgery. Smoking habits may compromise the efficacy of flapless implant procedures. © 2010 John Wiley & Sons A/S.

  11. Basin evolution at the SW Barents Sea margin and its conjugate off NE Greenland (United States)

    Faleide, Jan Inge; Wong, Po Wan; Helge Gabrielsen, Roy; Tsikalas, Filippos; Blaich, Olav A.; Planke, Sverre; Myklebust, Reidun


    The SW Barents Sea margin developed from a megashear zone which linked the Norwegian-Greenland Sea and the Artic Eurasia Basin during the initial Eocene opening. Within the dextral megashear system, a series of deep and narrow basins formed in the SW Barents Sea. These basins formed in response to multiple rift events and rapid differential subsidence. The distribution of salt structures both in the SW Barents Sea and on the conjugate NE Greenland margin reflects the Late Paleozoic basin configuration. Late Middle Jurassic to Early Cretaceous rifting affected all deep basins in the SW Barents Sea (e.g., Bjørnøya, Tromsø, Harstad and Sørvestsnaget basins) as on the mid-Norwegian margin and the conjugate NE Greenland margin. Following rifting, a wide region subsided and was covered by thick Cretaceous strata. Late Cretaceous-Paleocene rifting between Norway and Greenland was taken up within the megashear zone and pull-apart basins formed in the SW Barents Sea and in the Wandel Sea Basin in NE Greenland. Contraction/inversion formed structural highs separating distinct Late Cretaceous depocenters that continued to subside rapidly. The rifting culminated in crustal breakup and accretion of oceanic crust near the Paleocene-Eocene transition. NE Atlantic breakup was accompanied by large-scale igneous activity, which also affected parts of the SW Barents Sea margin. The sheared Senja FZ margin is segmented, each segment having different structural styles reflecting a complex interplay between the geometry of the sheared margin segments and the opening direction. A continental sliver was also cut off the SW Barents Sea margin, now forming the Greenland Ridge which is a protrusion of the NE Greenland margin. The continent-ocean transition is confined within a narrow zone, bounded by a characteristic marginal high along the Senja Fracture Zone. During Eocene, the Harstad and southern Sørvestsnaget basins developed as narrow, elongated, en echelon basins landward of the

  12. Evaluating potential man-induced changes in fish communities at estuarine and surf-zone areas: a long-term case study in Southern Brasil

    Directory of Open Access Journals (Sweden)

    Joao Vieira


    Full Text Available Anthropogenic impacts as environmental degradation and fisheries have been historically associated with changes in structure and dynamics of fish assemblages. A fundamental requisite to evaluate such man-induced changes on fish assemblages is the analysis of long-term time series that allow factoring out inter-annual and decadal natural variations in physical and biotic factors. Based on a standardized monthly long-term database (1997-2012 of experimental fish collections at shallow waters of estuarine and adjacent surf-zone areas of sub-tropical coastal lagoon in southern Brazil (32ºS-52ºW, we evaluated long-term trends in fish abundance and diversity and their correlates with fisheries and environmental factors. Overall species composition and species richness (S at both estuarine (95 and surf-zone (54 were quite similar across years (similarity=52.1 ± 5.8 SD, but there was high inter-annual variability correlated with local (temperature, salinity, regional (precipitation and global (ENSO factors. In the estuary, species richness decreased substantially between 2002 (S=45 and 2012 (S=22, and there were marked variability in abundance across years (CPUE mean =92.3; Min=34.5; Max=163.4. A contrasting pattern was observed at the surf-zone, with lower inter-annual variation in species richness, a marked decrease in fish abundance (CPUE mean=101.9; Min=31.3; Max=221.5. Bayesian generalized additive models (GAMs corroborate with those results and revealed a decrease in both species richness and abundance of both estuarine and adjacent surf-zone areas. Environmental conditions explained only partially the observed inter-annual and decadal variability in both estuarine and marine fish assemblages. Man-made changes associated with habitat loss and increasing fishing pressure could be responsible by some of long-term variations observed in these fish assemblages.

  13. Late Cretaceous-Cenozoic Evolution of the Central Andean Foreland Basin System in the Eastern Cordillera to Subandean Zone, Southern Bolivia (United States)

    Calle, A.; Horton, B. K.; Anderson, R. B.; Long, S. P.


    Evaluation of foreland basin deposystems and provenance across southern Bolivia reveals punctuated growth of the central Andean orogenic wedge. New and published sedimentology, provenance data, stratigraphy, subcrop mapping, and apatite (U-Th)/He thermochronometry along two transects (19.5, 21°S) from the easternmost Eastern Cordillera (EC) to the western Subandean Zone (SAZ) shed light on Late Cretaceous-Miocene thrust belt and foreland basin dynamics. Sediment dispersal patterns are constrained by paleocurrents, detrital zircon U-Pb geochronology, sandstone petrography, and conglomerate clast compositions. Spatial and temporal changes in the Andean thrust belt are recorded in asymmetric foreland basin thicknesses, facies distributions, and provenance within the EC (Incapampa and Camargo synclines) and SAZ (El Rosal and Entre Rios synclines). The >4 km uppermost Cretaceous-lower Miocene EC succession and ~2.5 km upper Oligocene-Miocene SAZ clastic successions record a shift from fluvial backbulge to pedogenic forebulge deposition. Braided, meandering, and lacustrine foredeep deposition records the most-rapid subsidence, with a later shift to progradational braided and alluvial fan deposition in the wedge-top zone. Growth strata preserved in EC and SAZ wedge-top deposits suggest unsteady eastward advance of the deformation front. Distal foreland deposits show west-directed paleocurrents with >1 Ga detrital zircon populations. Emerging Andean sources are indicated by east-directed paleocurrents, 36-25 Ma), Interandean Zone (IAZ, ~22-7 Ma) and SAZ (<6 Ma) can be linked to eastward passage of a flexural forebulge, recorded as a 50-200 m thick condensed zone in EC and SAZ basin fill. Integrated assessment of basin architecture, provenance, and exhumation highlights the potential influence of pre-Cenozoic IAZ heterogeneities on orogenic wedge growth.

  14. Evolution of the South Atlantic passive continental margin and lithosphere dynamic movement in Southern Brazil derived from zircon and apatite (U-Th-Sm)/He and fission-track data (United States)

    Krob, Florian; Stippich, Christian; Glasmacher, Ulrich A.; Hackspacher, Peter C.


    Passive continental margins are important geoarchives related to mantle dynamics, the breakup of continents, lithospheric dynamics, and other processes. The main concern yields the quantifying long-term lithospheric evolution of the continental margin between São Paulo and Laguna in southeastern Brazil since the Neoproterozoic. We put special emphasis on the reactivation of old fracture zones running into the continent and their constrains on the landscape evolution. In this contribution, we represent already consisting thermochronological data attained by fission-track and (U-Th-Sm)/He analysis on apatites and zircons. The zircon fission-track ages range between 108.4 (15.0) and 539.9 (68.4) Ma, the zircon (U-Th-Sm)/He ages between 72.9 (5.8) and 427.6 (1.8) Ma whereas the apatite fission-track ages range between 40.0 (5.3) and 134.7 (8.0) Ma, and the apatite (U-Th-Sm)/He ages between 32.1 (1.52) and 92.0 (1.86) Ma. These thermochronological ages from metamorphic, sedimentary and intrusive rocks show six distinct blocks (Laguna, Florianópolis, Curitiba, Ilha Comprida, Peruibe and Santos) with different evolution cut by old fracture zones. Furthermore, models of time-temperature evolution illustrate the differences in Pre- to post-rift exhumation histories of these blocks. The presented data will provide an insight into the complex exhumation history of the continental margin based on the existing literature data on the evolution of the Paraná basin in Brazil and the latest thermochronological data. We used the geological model of the Paraná basin supersequences (Rio Ivaí, Paraná, Gondwana I-III and Bauru) to remodel the subsidence and exhumation history of our consisting thermochronological sample data. First indications include a fast exhumation during the early Paleozoic, a slow shallow (northern blocks) to fast and deep (Laguna block) subduction from middle Paleozoic to Mesozoic time and a extremely fast exhumation during the opening of the South Atlantic

  15. [Effect of soil texture in unsaturated zone on soil nitrate accumulation and groundwater nitrate contamination in a marginal oasis in the middle of Heihe River basin]. (United States)

    Su, Yong-Zhong; Yang, Xiao; Yang, Rong


    In irrigated agricultural ecosystems, the accumulation, distribution and transfer of nitrate nitrogen (NO(3-)-N) in soil profile and groundwater nitrate pollution were influenced by irrigation and fertilization, and were closely related to soil textural characteristics. In this study, a monitoring section with 10 groundwater observation wells along Heihe River flood land-old oasis croplands-newly cultivated sandy croplands-fixed sandy land outside oasis was established in Pingchuan desert-oasis in Linze county in the middle of Heihe river basin, and groundwater NO(3-)-N concentration was continuously monitored. Soil texture and NO(3-)-N concentration in the unsaturated zone at different landscape locations were determined. The NO(3-)-N transfer change in soil profile, nitrate leaching of soils with different texture and fertility levels in the 0-100 cm layer were analyzed. The results indicated that the vertical distribution of soil texture was sandy loam in the 0-130 cm depth, loam in the 130-190 cm and clay loam in the 190-300 cm for the old oasis croplands. For newly cultivated sandy croplands, sand content was more than 80% in each soil layer of the 0-300 cm profile, although a thin clay layer occurred in the 140-160 cm depth. The clay layer occurred 160 cm below the sand-fixing zone outside oasis. There were significant correlations between soil NO(3-)-N concentration and silt + clay content, and the order of significant degree was the natural soils of sandy lands > the newly cultivated sandy croplands > the old oasis croplands. The loss of N leaching was closely correlated to the silt + caly content in the 0-100 cm soil depth. The groundwater NO(3-)-N concentration varied from 1.01 to 5.17 mg · L(-1), with a mean value of 2.65 mg · L(-1) and from 6.6 to 29.5 mg · L(-1), with an average of 20.8 mg · L(-1) in the area of old oasis croplands and the newly cultivated croplands, respectively. The averaged groundwater NO(3-)-N concentration in the area of newly

  16. Terminal suturing of Gondwana along the southern margin of South China Craton: Evidence from detrital zircon U-Pb ages and Hf isotopes in Cambrian and Ordovician strata, Hainan Island (United States)

    Xu, Yajun; Cawood, Peter A.; Du, Yuansheng; Zhong, Zengqiu; Hughes, Nigel C.


    Hainan Island, located near the southern end of mainland South China, consists of the Qiongzhong Block to the north and the Sanya Block to the south. In the Cambrian, these blocks were separated by an intervening ocean. U-Pb ages and Hf isotope compositions of detrital zircons from the Cambrian succession in the Sanya Block suggest that the unit contains detritus derived from late Paleoproterozoic and Mesoproterozoic units along the western margin of the West Australia Craton (e.g., Northampton Complex) or the Albany-Fraser-Wilkes orogen, which separates the West Australia and Mawson cratons. Thus, in the Cambrian the Sanya Block was not part of the South China Craton but rather part of the West Australian Craton and its environs. In contrast, overlying Late Ordovician strata display evidence for input of detritus from the Qiongzhong Block, which constituted part of the southeastern convergent plate margin of the South China Craton in the early Paleozoic. The evolving provenance record of the Cambrian and Ordovician strata suggests that the juxtaposition of South China and West Australian cratons occurred during the early to mid-Ordovician. The event was linked with the northern continuation of Kuungan Orogeny, with South China providing a record of final assembly of Gondwana.

  17. The Influence of Land Subsidence, Quarrying, Drainage, Irrigation and Forest Fire on Groundwater Resources and Biodiversity Along the Southern Po Plain Coastal Zone (Italy) (United States)

    Antonellini, M. A.; Mollema, P. N.


    The coastal zone of the southern Po plain is characterized by low lying land, which is reclaimed to permit settlements and agriculture. The history, tourism resorts and peculiar coastal environments make this territory attractive and valuable. Natural and fluid-extraction-induced land subsidence along with coastal erosion are major problems. Touristic development has strongly modified the landscape; coastal dunes have been in part removed to make room for hotels and quarrying has caused the formation of gravel pit lakes close to the shoreline. Protected natural areas include a belt of coastal dunes, wetlands, and the internal historical forests of San Vitale and Classe. The dunes have largely lost their original vegetation ecosystem, because years ago they have been colonized with pine trees to protect the adjacent farmland from sea spray. These pine forests are currently a fire hazard. Land reclamation drainage keeps the water table artificially low. Results of these anthropogenic disturbances on the hydrology include a decrease in infiltration rates, loss of freshwater surface bodies, encroachment of saltwater inland from the river estuaries, salinization of the aquifer, wetlands and soil with a loss in plant and aquatic species biodiversity. Feedback mechanisms are complex: as land subsidence continues, drainage increases at the same pace promoting sea-water intrusion. The salinity of the groundwater does not allow for plant species richness nor for the survival of large pine trees. Farmland irrigation and fires in the pine forests, on the other hand, allow for increased infiltration and freshening of the aquifer and at the same time promote plant species diversity. Our work shows that the characteristics of the southern Po coastal zone require integrated management of economic activities, natural areas, and resources. This approach is different from the ad hoc measures taken so far, because it requires long term planning and setting a priority of objectives.

  18. The Jurassic of Denmark and Greenland: Late Triassic – Jurassic development of the Danish Basin and the Fennoscandian Border Zone, southern Scandinavia

    Directory of Open Access Journals (Sweden)

    Nielsen, Lars Henrik


    Full Text Available The continental to marine Upper Triassic – Jurassic succession of the Danish Basin and the Fennoscandian Border Zone is interpreted within a sequence stratigraphic framework, and the evolution of the depositional basin is discussed. The intracratonic Permian–Cenozoic Danish Basin was formed by Late Carboniferous – Early Permian crustal extension followed by subsidence governed primarily by thermal cooling and local faulting. The basin is separated from thestable Precambrian Baltic Shield by the Fennoscandian Border Zone, and is bounded by basement blocks of the Ringkøbing–Fyn High towards the south. In Late Triassic – Jurassic times, the basin was part of the epeiric shallow sea that covered most of northern Europe. The Upper Triassic – Jurassic basin-fill is subdivided into two tectono-stratigraphic units by a basinwide intra-Aalenian unconformity. The Norian – Lower Aalenian succession was formed under relative tectonic tranquillity and shows an overall layer-cake geometry, except for areas with local faults and salt movements.Deposition was initiated by a Norian transgression that led to shallow marine deposition and was accompanied by a gradual climatic change to more humid conditions. Extensive sheets of shoreface sand and associated paralic sediments were deposited during short-lived forced regressions in Rhaetian time. A stepwise deepening and development of fully marine conditions followed in the Hettangian – Early Sinemurian. Thick uniform basinwide mud blankets weredeposited on an open storm-influenced shelf, while sand was trapped at the basin margins. This depositional pattern continued until Late Toarcian – Early Aalenian times when the basin became restricted due to renewed uplift of the Ringkøbing–Fyn High. In Middle Aalenian – Bathonian times, the former basin area was subjected to deep erosion, and deposition became restricted to the fault-bounded Sorgenfrei–Tornquist Zone. Eventually the fault margins

  19. Erosion of seafloor ridges at the top of the gas hydrate stability zone, Hikurangi margin, New Zealand : new insights from research cruises between 2005 and 2007

    Energy Technology Data Exchange (ETDEWEB)

    Pecher, I.A. [Heriot-Watt Univ., Edinburgh (United Kingdom). Inst. of Petroleum Engineering; Henrys, S.A.; Ellis, S. [SNS Science, Lower Hutt (New Zealand); Crutchley, G.; Fohrmann, M.; Gorman, A.R. [Otago Univ., Dunedin (New Zealand). Dept. of Geology; Greinert, J. [Ghent Univ., Ghent (Belgium). Renard Centre of Marine Geology; Chiswell, S.M. [NIWA, Wellington (New Zealand)


    Studies have suggested that the erosion of subsea ridges on the Hikurangi margin is related to fluctuating levels of gas hydrate stability in the surrounding ocean. This paper described 3 field studies conducted to examine the region. The studies included a 15-month time series of temperature sensors deployed at 580 meters on the Ritchie Banks. Seismic data showed evidence of bottom simulating reflectors (BSRs). Water temperature fluctuations occurred at lower frequencies and higher amplitudes than previous studies indicated. Data obtained in the studies indicated that changes in temperature are having an impact on the sub-seafloor gas hydrates. Consolidated mudstones were observed in dredge samples obtained during the expeditions. The study indicated that repeated pore volume expansion and contraction caused by the releases of gas during gas hydrate dissociation are contributing to sea floor weakening in the region. It was concluded that gas hydrate freeze-thaw events are contributing to the dilation of fractures in mudstones and weakening the sea floor. However, gas pockets beneath the ridge may also be contributing to fracturing of the sea floor. 35 refs., 1 tab., 8 figs.

  20. Migration and Interaction in a Contact Zone: mtDNA Variation among Bantu-Speakers in Southern Africa (United States)

    Barbieri, Chiara; Vicente, Mário; Oliveira, Sandra; Bostoen, Koen; Rocha, Jorge; Stoneking, Mark; Pakendorf, Brigitte


    Bantu speech communities expanded over large parts of sub-Saharan Africa within the last 4000–5000 years, reaching different parts of southern Africa 1200–2000 years ago. The Bantu languages subdivide in several major branches, with languages belonging to the Eastern and Western Bantu branches spreading over large parts of Central, Eastern, and Southern Africa. There is still debate whether this linguistic divide is correlated with a genetic distinction between Eastern and Western Bantu speakers. During their expansion, Bantu speakers would have come into contact with diverse local populations, such as the Khoisan hunter-gatherers and pastoralists of southern Africa, with whom they may have intermarried. In this study, we analyze complete mtDNA genome sequences from over 900 Bantu-speaking individuals from Angola, Zambia, Namibia, and Botswana to investigate the demographic processes at play during the last stages of the Bantu expansion. Our results show that most of these Bantu-speaking populations are genetically very homogenous, with no genetic division between speakers of Eastern and Western Bantu languages. Most of the mtDNA diversity in our dataset is due to different degrees of admixture with autochthonous populations. Only the pastoralist Himba and Herero stand out due to high frequencies of particular L3f and L3d lineages; the latter are also found in the neighboring Damara, who speak a Khoisan language and were foragers and small-stock herders. In contrast, the close cultural and linguistic relatives of the Herero and Himba, the Kuvale, are genetically similar to other Bantu-speakers. Nevertheless, as demonstrated by resampling tests, the genetic divergence of Herero, Himba, and Kuvale is compatible with a common shared ancestry with high levels of drift, while the similarity of the Herero, Himba, and Damara probably reflects admixture, as also suggested by linguistic analyses. PMID:24901532

  1. Migration and interaction in a contact zone: mtDNA variation among Bantu-speakers in Southern Africa.

    Directory of Open Access Journals (Sweden)

    Chiara Barbieri

    Full Text Available Bantu speech communities expanded over large parts of sub-Saharan Africa within the last 4000-5000 years, reaching different parts of southern Africa 1200-2000 years ago. The Bantu languages subdivide in several major branches, with languages belonging to the Eastern and Western Bantu branches spreading over large parts of Central, Eastern, and Southern Africa. There is still debate whether this linguistic divide is correlated with a genetic distinction between Eastern and Western Bantu speakers. During their expansion, Bantu speakers would have come into contact with diverse local populations, such as the Khoisan hunter-gatherers and pastoralists of southern Africa, with whom they may have intermarried. In this study, we analyze complete mtDNA genome sequences from over 900 Bantu-speaking individuals from Angola, Zambia, Namibia, and Botswana to investigate the demographic processes at play during the last stages of the Bantu expansion. Our results show that most of these Bantu-speaking populations are genetically very homogenous, with no genetic division between speakers of Eastern and Western Bantu languages. Most of the mtDNA diversity in our dataset is due to different degrees of admixture with autochthonous populations. Only the pastoralist Himba and Herero stand out due to high frequencies of particular L3f and L3d lineages; the latter are also found in the neighboring Damara, who speak a Khoisan language and were foragers and small-stock herders. In contrast, the close cultural and linguistic relatives of the Herero and Himba, the Kuvale, are genetically similar to other Bantu-speakers. Nevertheless, as demonstrated by resampling tests, the genetic divergence of Herero, Himba, and Kuvale is compatible with a common shared ancestry with high levels of drift, while the similarity of the Herero, Himba, and Damara probably reflects admixture, as also suggested by linguistic analyses.

  2. Rangeland dynamics in South Omo Zone of Southern Ethiopia: Assessment of rangeland condition in relation to altitude and Grazing types


    Terefe, A.; Ebro, A.; Tessema, Z.K.


    A study was undertaken in Hamer and Benna-Tsemay districts of the Southern Ethiopia with the objective to determine the condition of the rangelands for grazing animals as influenced by altitude and grazing types. The rangelands in each of the study districts were stratified based on altitude and grazing types. In the study districts, a total of 32, 3, 2, 7 and 29 species of grasses, legumes, sedges, other herbaceous plants and woody species were identified, respectively. The common and/or dom...

  3. Tectonic growth of a Cretaceous-Eocene accretionary orogen formed at the southern margin of the Caribbean Plate: integrated geological insights from northernmost Colombia (United States)

    Cardona, A.; Weber, M. B.; Bayona, G.; Jaramillo, C.; Montes, C.; Ojeda, G.; Duque, J. F.; Salazar, C. A.


    Geological characteristics from the Cretaceous to Eocene metamorphic and igneous basement rocks from the Guajira and the NW corner of the Sierra Nevada de Santa Marta massifs in the northern Colombian Caribbean region, and the stratigraphy of adjacent basins, reveal different stages of growth of a segmented Late Cretaceous to Eocene accretionary orogen formed by interaction between the NW margin of South America and the Caribbean plate. Extensive intercalations of metavolcano-sedimentary rocks in the Santa Marta region, chemical composition of spinels and pyroxenes from serpentinized mantle tectonites and gabbros, as well as whole rock geochemistry from basaltic dykes from the Guajira massifs, record the evolution of a Cretaceous intra-oceanic arc in a succesion of Mariana- and Chile-type subduction styles. Geological and positive gravity signatures suggest that this arc was accreted and tectonically underplated to the continental margin of South America, creating a Maastrichian-Paleocene syn-orogenic basin, presently cropping out in the Cesar-Rancheria valley. After this collisional event, subduction of the Caribbean plate under South America started, as revealed by intrusion of composite stitched Late Paleocene-Eocene granitoids in the NW corner of the SNSM and Guajira massifs. These plutons show continental calc-alkaline geochemical signatures and more evolved Sr and Nd isotopic compositions than juvenile and older intra-oceanic arc magmatic rocks. This new subduction environment is linked to the convergence between North and South America at this time. Low pressure estimations and fast cooling rates between 450-250° for the Eocene granitoids in the Guajira and Santa Marta regions, indicate shallow < 7 Km depths of intrusion. Local unconformable stratigraphic relationships with Eocene-Miocene sediments at the Guajira region and overimposed post-magmatic low temperature deformation in some of these granitoids suggest an important Late Eocene unroofing and

  4. Tectonic Evolution of Mozambique Ridge in East African continental margin (United States)

    Tang, Yong


    Tectonic Evolution of Mozambique Ridge in East African continental margin Yong Tang He Li ES.Mahanjane Second Institute of Oceanography,SOA,Hangzhou The East Africa passive continental margin is a depression area, with widely distributed sedimentary wedges from southern Mozambique to northern Somali (>6500km in length, and about 6km in thickness). It was resulted from the separation of East Gondwana, and was developed by three stages: (1) rifting in Early-Middle Jurassic; (2) spreading from Late Jurassic to Early Cretaceous; (3) drifting since the Cretaceous period. Tectonic evolution of the Mozambique continental margin is distinguished by two main settings separated by a fossil transform, the Davie Fracture Zone; (i) rifting and transform setting in the northern margin related to opening of the Somali and Rovuma basins, and (ii) rifting and volcanism setting during the opening of the Mozambique basin in the southern margin. 2D reflection seismic investigation of the crustal structure in the Zambezi Delta Depression, provided key piece of evidence for two rifting phases between Africa and Antarctica. The magma-rich Rift I phase evolved from rift-rift-rift style with remarkable emplacement of dyke swarms (between 182 and 170 Ma). Related onshore outcrops are extensively studied, the Karoo volcanics in Mozambique, Zimbabwe and South Africa, all part of the Karoo "triple-junction". These igneous bodies flow and thicken eastwards and are now covered by up to 5 km of Cretaceous and Tertiary sediments and recorded by seismic and oil exploration wells. Geophysical and geological data recorded during oceanographic cruises provide very controversial results regarding the nature of the Mozambique Ridge. Two conflicting opinions remains open, since the early expeditions to the Indian Ocean, postulating that its character is either magmatic (oceanic) or continental origin. We have carried out an China-Mozambique Joint Cruise(CMJC) on southern Mozambique Basin on 1st June to

  5. Cambrian intermediate-mafic magmatism along the Laurentian margin: Evidence for flood basalt volcanism from well cuttings in the Southern Oklahoma Aulacogen (U.S.A.) (United States)

    Brueseke, Matthew E.; Hobbs, Jasper M.; Bulen, Casey L.; Mertzman, Stanley A.; Puckett, Robert E.; Walker, J. Douglas; Feldman, Josh


    The Southern Oklahoma Aulocogen (SOA) stretches from southern Oklahoma through the Texas panhandle and into Colorado and New Mexico, and contains mafic through silicic magmatism related to the opening of the Iapetus Ocean during the early Cambrian. Cambrian magmatic products are best exposed in the Wichita Mountains (Oklahoma), where they have been extensively studied. However, their ultimate derivation is still somewhat contentious and centers on two very different models: SOA magmatism has been suggested to occur via [1] continental rifting (with or without mantle plume emplacement) or [2] transform-fault related magmatism (e.g., leaky strike-slip faults). Within the SOA, the subsurface in and adjacent to the Arbuckle Mountains in southern Oklahoma contains thick sequences of mafic to intermediate lavas, intrusive bodies, and phreatomagmatic deposits interlayered with thick, extensive rhyolite lavas, thin localized tuffs, and lesser silicic intrusive bodies. These materials were first described in the Arbuckle Mountains region by a 1982 drill test (Hamilton Brothers Turner Falls well) and the best available age constraints from SOA Arbuckle Mountains eruptive products are 535 to 540 Ma. Well cuttings of the mafic through intermediate units were collected from that well and six others and samples from all but the Turner Falls and Morton wells are the focus of this study. Samples analyzed from the wells are dominantly subalkaline, tholeiitic, and range from basalt to andesite. Their overall bulk major and trace element chemistry, normative mineralogy, and Srsbnd Nd isotope ratios are similar to magmas erupted/emplaced in flood basalt provinces. When compared with intrusive mafic rocks that crop out in the Wichita Mountains, the SOA well cuttings are geochemically most similar to the Roosevelt Gabbros. New geochemical and isotope data presented in this study, when coupled with recent geophysical work in the SOA and the coeval relationship with rhyolites, indicates

  6. Architecture of ductile-type, hyper-extended passive margins: Geological constraints from the inverted Cretaceous basin of the North-Pyrenean Zone ('Chaînons Béarnais', Western Pyrenees) (United States)

    Corre, Benjamin; Lagabrielle, Yves; Labaume, Pierre; Lahfid, Abdeltif; Boulvais, Philippe; Bergamini, Geraldine; Fourcade, Serge; Clerc, Camille


    Sub-continental lithospheric mantle rocks are exhumed at the foot of magma-poor distal passive margins as a response to extreme stretching of the continental crust during plate separation. Remnants of the Northern Iberian paleo-passive margin are now exposed in the North-Pyrenean Zone (NPZ) and represent field analogues to study the processes of continental crust thinning and subcontinental mantle exhumation. The NPZ results from the inversion of basins opened between the Iberia and Europa plates during Albo-Cenomanian times. In the western NPZ, the 'Chaînons Béarnais' ranges display a fold-and-thrust structure involving the Mesozoic sedimentary cover, decoupled from its continental basement and associated with peridotite bodies in tectonic contact with Palaeozoic basement lenses of small size. Continental extension developed under hot thermal conditions, as demonstrated by the syn-metamorphic Cretaceous ductile deformation affecting both the crustal basement and the allochthonous Mesozoic cover. In this study, we present structural and geochemical data providing constraints to reconstruct the evolution of the northern Iberia paleo-margin. Field work confirms that the pre-rift Mesozoic cover is intimately associated to mantle rocks and to thin tectonic lenses of crustal basement. It also shows that the pre-rift cover was detached from its bedrock at the Keuper evaporites level and was welded to mantle rocks during their exhumation at the foot of the hyper-extended margin. The crust/mantle detachment fault is a major shear zone characterized by anastomosed shear bands defining a plurimetric phacoidal fabric at the top of the serpentinized mantle. The detachment is marked by a layer of metasomatic rocks, locally 20 meters thick, made of talc-chlorite-pyrite-rich rocks that developped under greenschist facies conditions. Raman Spectroscopy on Carbonaceous Materials (RSCM), performed on the Mesozoic cover reveal that the entire sedimentary pile underwent temperatures

  7. Prevalence of smear positive pulmonary tuberculosis and associated risk factors among prisoners in Hadiya Zone prison, Southern Ethiopia. (United States)

    Fuge, Terefe G; Ayanto, Samuel Y


    People concentrated in congregated systems such as prisons, are important but often neglected reservoirs for tuberculosis transmission, and threaten those in the outside community. The condition is more serious in Africa particularly in Sub-Saharan Africa (SSA) due to its poor living conditions and ineffective health services. This study was conducted to determine the prevalence of smear positive pulmonary tuberculosis and associated risk factors among prisoners in Hadiya Zone prison. A cross-sectional survey was carried out from May to June 2013 in Hadiya Zone prison. Prison inmates who had history of cough for at least a week were included in the study. Three morning sputum samples were collected from suspected inmates and examined through compound light microscopy. The data obtained was analyzed using statistical software like Epidata and STATA. A total of 164 prisoners were included in the survey using active screening strategy and the point prevalence of smear positive pulmonary tuberculosis (PTB) in the prison was 349.2 per 100,000 populations; about three times higher than its prevalence in the general population. Even though lack of visit from family was the only variable identified as a risk factor for PTB (P = 0.029), almost all of the PTB positive cases were rural residents, farmers, male youngsters and those who shared cell with TB patients and chronically coughing persons as well as those who stayed in a cell that contains >100 inmates. There is high prevalence of TB in Hadiya Zone prison with possible active transmission of TB within the prison. The study also documented a number of factors which may facilitate exposures to TB though most of them are not significantly associated. Therefore, strong cooperation between prison authorities and the national tuberculosis control programmes is urgently required to develop locally appropriate interventions to reduce transmission.

  8. Teleconnection between the South Atlantic convergence zone and the southern Indian Ocean: Implications for tropical cyclone activity (United States)

    DeBlander, Evan; Shaman, Jeffrey


    A link between anomalous austral summer convection over the South Atlantic convergence zone (SACZ) and atmospheric conditions over the South Indian Ocean is investigated. Interannual north-south shifts in the SACZ produce a dipole of anomalous convection and precipitation over South America. The South Atlantic convergence zone index (SACZI) capturing this variability is presented and associated with a midlatitude Rossby wave train that propagates from South America eastward and south of Africa before curving north into the tropical Indian Ocean. This wave train is reproduced using Rossby wave ray tracing and simulations with a linearized barotropic vorticity equation model forced with divergence and convergence consistent with the observed dipole of anomalous convection. The wave train acts to excite anomalies in wind shear and relative humidity over the tropical south Indian Ocean, which in turn impact tropical cyclone (TC) genesis and distribution over this region. We find that changes in the wind shear and relative humidity associated with the SACZI effect changes in TC genesis, which result in a change in observed TC days over portions of the South Indian Ocean.

  9. Structure of the Cocos subduction zone in central and southern Mexico from three-dimensional body-wave attenuation and travel time tomography (United States)

    Chen, T.; Clayton, R. W.


    The 3D P- and S-wave attenuation and velocity structure of the Cocos subduction zone in Mexico is imaged using seismic events recorded by the MASE (100 seismometers running across central Mexico, 2005-2007) and VEOX (47 seismometers running across southern Mexico, 2007-2009) arrays, supplemented by stations from the National Seismic Network in Mexico (SSN). Using a spectral-decay method, we obtain a path attenuation operator t* for each seismogram in the frequency band 1 to 30 Hz, depending on the signal quality. These measurements are then inverted for 3D spatial variations in attenuation. Direct body-wave arrivals from local events are used for 3D velocity inversion. Deeper velocity structures along MASE and VEOX arrays are obtained by including teleseismic events. Inversion results show low attenuation associated with the Cocos slab, and show the slab dip angle increases from central to southern Mexico. High attenuation is imaged in the mantle wedge and the crust above. The highest attenuation is found in the crust near the active Los Tuxtlas volcanic field, probably related to the dehydration and melting process. Low velocity is observed in the mantle wedge and the crust above from velocity inversion. The Cocos slab is traced as high-velocity structure. The Cocos slab dips down to about 500 km in central Mexico along MASE array as shown by previous study (Perez-Campos, GRL, 2008). In southern Mexico along VEOX line, no clear continuous Cocos slab is observed deeper than about 150 km, which is also found by receiver function studies (Kim et al., in press; Perez-Campos et al., in press). There are some indications that the Cocos slab in southern Mexico near the Isthmus of Tehuantepec is truncated by some high-velocity structure dipping south from the Gulf of Mexico. This anomalous south-dipping structure is also seen in receiver function images, and may be related to the collision between the Yucatan Block and Mexico in the Miocene (Kim et al., in press).

  10. Resolving arc processes through detrital zircon U-Pb geochronology and geochemistry: a case study from the southern California Mesozoic convergent margin (United States)

    Johnston, S. M.; Kylander-Clark, A. R.


    Detrital zircon geochronology has been widely exploited to establish temporal characteristics in sedimentary source terranes. Detrital zircon geochemistry, however, has been largely overlooked given results from continentally derived igneous zircon that show subtle intersample variation in trace-element concentrations, and which make correlation between detrital zircon and their host terrane difficult. Nevertheless, recent studies suggest systematically variable geochemistry in McCoy Mountain detrital zircons derived from the southern California Mesozoic arc, and our preliminary data from the Peninsular Ranges batholith indicates strong correlations between whole-rock and zircon geochemistry. Here, we present coupled U-Pb geochronology and geochemistry measured by laser ablation split stream ICPMS on detrital zircons from Nacimiento block forearc sediments in Central California to characterize temporal and geochemical trends in the adjacent Mesozoic arc terrane. 1098 grains of Mesozoic age analyzed from 22 samples in the Nacimiento block define three periods of high magmatic flux in the Permian (270-250 Ma), Jurassic (170-140 Ma), and late Cretaceous (115-90 Ma). Zircon from the Permian arc is the least abundant of the three magmatic pulses, although they consistently display elevated Yb/Gd and U/Yb. Jurassic zircons display consistently low U/Yb, variably elevated Yb/Gd, abruptly higher Th/U and LREE from 155-145, and abruptly lower REE concentrations from 145-140 Ma. Zircon from the Cretaceous arc displays gradually increasing U/Yb, Th/U and LREE, with abruptly decreasing Yb/Gd at 95 Ma. The geochemical trends observed in the Nacimiento block detrital zircons of Cretaceous age are strikingly similar to temporal changes in geochemistry known from Cretaceous arc rocks of the Mojave and Peninsular Ranges, and strongly suggest a southern California provenance for Nacimiento block sediments. Furthermore, the similarity of geochemical trends between Cretaceous detrital

  11. Basin analysis in the Southern Tethyan margin: Facies sequences, stratal pattern and subsidence history highlight extension-to-inversion processes in the Cretaceous Panormide carbonate platform (NW Sicily) (United States)

    Basilone, Luca; Sulli, Attilio


    In the Mediterranean, the South-Tethys paleomargin experienced polyphased tectonic episodes and paleoenvironmental perturbations during Mesozoic time. The Cretaceous shallow-water carbonate successions of the Panormide platform, outcropping in the northern edge of the Palermo Mountains (NW Sicily), were studied by integrating facies and stratal pattern with backstripping analysis to recognize the tectonics vs. carbonate sedimentation interaction. The features of the Requienid limestone, including geometric configuration, facies sequence, lithological changes and significance of the top-unconformity, highlight that at the end of the Lower Cretaceous the carbonate platform was tectonically dismembered in various rotating fault-blocks. The variable trends of the subsidence curves testify to different responses, both uplift and downthrow, of various platform-blocks impacted by extensional tectonics. Physical stratigraphic and facies analysis of the Rudistid limestone highlight that during the Upper Cretaceous the previously carbonate platform faulted-blocks were subjected to vertical movements in the direction opposite to the displacement produced by the extensional tectonics, indicating a positive tectonic inversion. Comparisons with other sectors of the Southern Tethyan and Adria paleomargins indicate that during the Cretaceous these areas underwent the same extensional and compressional stages occurring in the Panormide carbonate platform, suggesting a regional scale significance, in time and kinematics, for these tectonic events.

  12. Mercury in marine fish, mammals, seabirds, and human hair in the coastal zone of the southern Baltic. (United States)

    Bełdowska, Magdalena; Falkowska, Lucyna

    Mercury (Hg), aside from having high toxicity, is characterized by its ability to biomagnify in the marine trophic chain. This is an important problem especially in estuaries, or in the coastal zone, particularly near the mouths of large rivers. This study was conducted in the years 2001-2011, in the coastal zone of the Baltic Sea near to the mouth of the River Vistula, which is the second biggest river discharging into the Baltic. Mercury concentration was measured in the tissues and organs of cod, flounder, herring, seals (living in the wild and in captivity), great black-backed gulls, and African penguins from Gdańsk Zoo, and also in human hair. Penguins and seals at the seal sanctuary in Hel were fed only herring. In marine birds and mammals and in the pelagic herring, the highest Hg concentration was observed in the kidney and in the liver, while in cod and flounder (located on a higher trophic level) the muscles were the most contaminated with mercury. In gray seals living in the seal sanctuary, Hg concentration in all analyzed tissues and organs except the kidneys was lower in comparison with seals living in the wild. The comparatively small share of fish in the diet of local Polish people and their preference towards the consumption of herring contributed to low concentration of Hg in their hair. The protective mechanisms related to detoxification and elimination of mercury were shown to be more effective in the seals than in the penguins, despite the former consuming around 10 times more food per day.

  13. Repeated occurrences of methanogenic zones, diagenetic dolomite formation and linked silicate alteration in southern Bering Sea sediments (Bowers Ridge, IODP Exp. 323 Site U1341) (United States)

    Wehrmann, L. M.; Ockert, C.; Mix, A. C.; Gussone, N.; Teichert, B. M. A.; Meister, P.


    Diagenetic precipitates, such as dolomite, and the chemistry of residual deeply buried porewater often represent the only traces of past biogeochemical activity in marine sediments. A 600 m thick sedimentary section, recently drilled at Integrated Ocean Drilling Program (IODP) Site U1341 on Bowers Ridge (southern Bering Sea), provides insight into such a 4.3 Ma old paleo-diagenetic archive. Hard-lithified calcite-dolomite layers, and laminae of disseminated carbonate, were recovered in diatom-rich sediments over a depth range of 400 m. Carbon isotope values of the diagenetic carbonates between -16.6 and -14.4‰ (VPDB) and strontium isotope ratios of dolomites close to past seawater values suggest carbonate precipitation induced by the production of dissolved inorganic carbon (DIC) during elevated rates of organic carbon mineralization, primarily via sulfate reduction, at shallow sediment depth below the paleo-seafloor. Diagenetic carbonates at 280-440 m below seafloor were likely also produced by the intermittent onset of sulfate reduction coupled to the anaerobic oxidation of methane (AOM) at sulfate-methane transition zones (SMTZ). These microbially mediated processes do not occur in the sediment at this site at present but were likely connected to the presence of a methanogenic zone at 2.58-2.51 Ma. A minimum in sulfate concentrations in modern porewaters and low sedimentary Ba/Al ratios resulting from former sulfate depletion are reminiscent of the presence of this large methanogenic zone. The minimum in sulfate concentrations is reflected in a minimum in magnesium concentrations, less radiogenic strontium and isotopically light calcium in the porewater. It is proposed that magnesium was removed from the porewater during carbonate precipitation and volcanic ash alteration which occurred in the former methanogenic zone and also released strontium with a less radiogenic isotope ratio and isotopically light calcium into the porewater. The isotopic composition of

  14. Assessing vulnerability mapping and protection zones of karst spring waters and validating by the joint use of natural and artificial tracers. The case of Auta Spring (Southern Spain) (United States)

    Marín, Ana Isabel; Mudarra, Matías; Andreo, Bartolomé


    Delineation of protection zones for water supply and implementation of proper land-use practices in surrounding areas are crucial aspects for a sustainable use of valuable drinking water resources. This is even more important in karst aquifers, which are particularly sensitive to contamination, having a very low self-cleaning capacity due to their structure and hydrological behavior. Consequently, specific methodologies adapted to the particular characteristics of karst media are necessary. In this work, an approach for protection zoning of the pilot site of Auta karst spring (southern Spain) is proposed, based on the application of COP+K method for contamination vulnerability and validation of results by natural (organic) tracers of infiltration (NO3-, TOC, intrinsic fluorescence) and by a dye tracer test conducted on June, 2011 (injecting 500 mg uranine). The aquifer drained by Auta spring (8.5 km2) presents a complex geological structure, formed by Jurassic dolostones and limestones highly folded and fractured. Recharge takes place by the infiltration of rainfall through karst landforms and also by losses in an adjacent river when it flows over the carbonate outcrops (dye injection point). Drainage is mainly through several springs located at the southwest, including Auta spring and 5 overflow springs. The source vulnerability map obtained by applying COP+K method can be adopted as the baseline to delineate the protection zones, through the conversion from vulnerability classes to degrees of protection. Dye tracer test and natural tracers of infiltration corroborate that aquifer sectors influenced by the river can be extremely vulnerable to pollution, but also well-developed exokarst features. In fact, slight evidences of pollution have been detected during the study period, with relatively-high NO3- contents and high fluorescence linked to bacteriological activity in Auta spring water. The jointly use of natural and artificial tracers constitute a reliable and

  15. A tight balance between natural selection and gene flow in a southern African arid-zone endemic bird. (United States)

    Ribeiro, Ångela M; Lloyd, Penn; Bowie, Rauri C K


    Gene flow is traditionally thought to be antagonistic to population differentiation and local adaptation. However, recent studies have demonstrated that local adaptation can proceed provided that selection is greater than the homogenizing effects of gene flow. We extend these initial studies by combining ecology (climate), phenotype (body size), physiological genetics (oxidative phosphorylation genes), and neutral loci (nuclear microsatellites and introns) to test whether selection can counter-balance gene flow and hence promote local adaptation in a bird whose distribution spans an aridity gradient. Our results show that the Karoo scrub-robin's climatic niche is spatially structured, providing the potential for local adaptation to develop. We found remarkably discordant patterns of divergence among mtDNA, morphology, and neutral loci. For the mitochondrial genes, two amino acid replacements, strong population structure and reduced gene flow were associated with the environmental gradient separating western coastal sites from the interior of southern Africa. In contrast, morphology and the neutral loci exhibited variation independent of environmental variables, and revealed extensive levels of gene flow across the aridity gradient, 50 times larger than the estimates for mitochondrial genes. Together, our results suggest that selective pressures on physiology, mediated by the mitochondrial genome, may well be a common mechanism for facilitating local adaptation to new climatic conditions. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  16. The influence of El Niño-Southern Oscillation (ENSO) cycles on wave-driven sea-floor sediment mobility along the central California continental margin (United States)

    Storlazzi, Curt D.; Reid, Jane A.


    Ocean surface waves are the dominant temporally and spatially variable process influencing sea floor sediment resuspension along most continental shelves. Wave-induced sediment mobility on the continental shelf and upper continental slope off central California for different phases of El Niño-Southern Oscillation (ENSO) events was modeled using monthly statistics derived from more than 14 years of concurrent hourly oceanographic and meteorologic data as boundary input for the Delft SWAN wave model, gridded sea floor grain-size data from the usSEABED database, and regional bathymetry. Differences as small as 0.5 m in wave height, 1 s in wave period, and 10° in wave direction, in conjunction with the spatially heterogeneous unconsolidated sea-floor sedimentary cover, result in significant changes in the predicted mobility of continental shelf surficial sediment in the study area. El Niño events result in more frequent mobilization on the inner shelf in the summer and winter than during La Niña events and on the outer shelf and upper slope in the winter months, while La Niña events result in more frequent mobilization on the mid-shelf during spring and summer months than during El Niño events. The timing and patterns of seabed mobility are addressed in context of geologic and biologic processes. By understanding the spatial and temporal variability in the disturbance of the sea floor, scientists can better interpret sedimentary patterns and ecosystem structure, while providing managers and planners an understanding of natural impacts when considering the permitting of offshore activities that disturb the sea floor such as trawling, dredging, and the emplacement of sea-floor engineering structures.

  17. Cenozoic faults and faulting phases in the western Tarim Basin (NW China): Effects of the collisions on the southern margin of the Eurasian Plate (United States)

    Li, Yue-Jun; Zhang, Qiang; Zhang, Guang-Ya; Tian, Zuo-Ji; Peng, Geng-Xin; Qiu, Bin; Huang, Zhi-Bin; Luo, Jun-Cheng; Wen, Lei; Zhao, Yan; Jia, Tie-Gan


    The Bachu Rise in the western Tarim Basin is the fore-bulge of the Kunlun late Cenozoic intra-continental foreland basin system formed under the far-field effect of India-Asia collision. Cenozoic faults and faulting are abnormally developed in the Bachu Rise and its adjacent area. Taking the Niaoshan-Gudongshan area on the southern boundary of the Bachu Rise as the key study area, 5 Cenozoic faulting phases were identified in the Bachu Rise and its adjacent area after careful seismic interpretation. They are end Cretaceous ∼ beginning Paleogene (ca. 65 Ma) décollement-thrusting, end Paleogene ∼ beginning Neogene (ca. 23 Ma) décollement-thrusting, end Miocene ∼ beginning Pliocene (ca. 5 Ma) basement-involved thrusting, late Pliocene ∼ early Pleistocene (ca. 3-2 Ma) normal faulting, middle Pleistocene ∼ Holocene (ca. <1.5 Ma) décollement-thrusting and strike-slip faulting. The Middle Cambrian and Paleogene gypsum-salt layers serve as the two main décollement layers in the study area. Thrusting of ca. 65 Ma was under the far-field effect of the collision between Lhasa (part of the Cimmerian Continent) and Asia; and the other 4 Cenozoic faulting phases were all under the far-field effect of the India-Asia collision. The late Cenozoic faulting is characterized by pulse thrust. There is one tectonic pause between each two successive thrust pulses. The compressive tectonic stress is weaker and even evolved into a slight tensional tectonic stress and forms normal fault in the tectonic pauses.

  18. P-T and structural constraints of lawsonite and epidote blueschists from Liberty Creek and Seldovia: Tectonic implications for early stages of subduction along the southern Alaska convergent margin (United States)

    López-Carmona, Alicia; Kusky, Timothy M.; Santosh, M.; Abati, Jacobo


    The southern Alaska convergent margin contains several small belts of sedimentary and volcanic rocks metamorphosed to blueschist facies, located along the Border Ranges fault on the contact between the Wrangellia and Chugach terranes. These belts are significant in that they are the most inboard, and thus probably contain the oldest record of Triassic-Jurassic northward-directed subduction beneath Wrangellia. The Liberty Creek HP-LT schist belt is the oldest and the innermost section of the Chugach terrane. Within this belt lawsonite blueschists contains an initial high-pressure assemblage formed by lawsonite + phengite + chlorite + sphene + albite ± apatite ± carbonates and quartz. Epidote blueschists are composed of sodic, sodic-calcic and calcic amphiboles + epidote + phengite + chlorite + albite + sphene ± carbonates and quartz. P-T pseudosections computed from four representative samples constrain maximum pressures at 16 kbar and 250-280 °C for the Lawsonite-bearing blueschists, and 15 kbar and 400-500 °C for the epidote-bearing blueschists, suggesting a initial subduction stage of 50-55 km depth. The growth of late albite porphyroblasts in all samples suggests a dramatic decompression from ca. 9 kbar to 5 kbar. The Liberty Creek schists can be correlated with the Seldovia blueschist belt on the Kenai Peninsula. Metamorphism in both terranes took place in the Early Jurassic (191-192 Ma), recording an early stage of subduction beneath Wrangellia. In the nearby terranes of the same margin, the age of metamorphism records an early stage of subduction at 230 Ma. Based on this difference in age, a maximum of 40 Ma were necessary to subduct the protoliths of the Seldovia and Liberty Creek blueschists to depths of circa 50-55 km, suggesting a minimum vertical component of subduction of 1.2-1.5 cm/year.

  19. Reactivation of the Archean-Proterozoic suture along the southern margin of Laurentia during the Mazatzal orogeny: Petrogenesis and tectonic implications of ca. 1.63 Ga granite in southeastern Wyoming (United States)

    Jones, Daniel S.; Barnes, Calvin G.; Premo, Wayne R.; Snoke, Arthur W.


    The presence of ca. 1.63 Ga monzogranite (the “white quartz monzonite”) in the southern Sierra Madre, southeastern Wyoming, is anomalous given its distance from the nearest documented plutons of similar age (central Colorado) and the nearest contemporaneous tectonic margin (New Mexico). It is located immediately south of the Cheyenne belt—a ca. 1.75 Ga Archean-Proterozoic tectonic suture. New geochronological, isotopic, and geochemical data suggest that emplacement of the white quartz monzonite occurred between ca. 1645 and 1628 Ma (main pulse ca. 1628 Ma) and that the white quartz monzonite originated primarily by partial melting of the Big Creek Gneiss, a modified arc complex. There is no evidence that mafic magmas were involved. Open folds of the ca. 1750 Ma regional foliation are cut by undeformed white quartz monzonite. On a regional scale, rocks intruded by the white quartz monzonite have experienced higher pressure and temperature conditions and are migmatitic as compared to the surrounding rocks, suggesting a genetic relationship between the white quartz monzonite and tectonic exhumation. We propose that regional shortening imbricated the Big Creek Gneiss, uplifting the now-exposed high-grade rocks of the Big Creek Gneiss (hanging wall of the thrust and wall rock to the white quartz monzonite) and burying correlative rocks, which partially melted to form the white quartz monzonite. This tectonism is attributed to the ca. 1.65 Ga Mazatzal orogeny, as foreland shortening spread progressively into the Yavapai Province. Mazatzal foreland effects have also been described in the Great Lakes region and have been inferred in the Black Hills of South Dakota. We suggest that the crustal-scale rheologic contrast across the Archean-Proterozoic suture, originally developed along the southern margin of Laurentia, and including the Cheyenne belt, facilitated widespread reactivation of that boundary during the Mazatzal orogeny. This finding emphasizes the degree to

  20. Shear wave velocity structure in the lithosphere and asthenosphere across the Southern California continent and Pacific plate margin using inversion of Rayleigh wave data from the ALBACORE project. (United States)

    Price, A. C.; Weeraratne, D. S.; Kohler, M. D.; Rathnayaka, S.; Escobar, L., Sr.


    single plate as well as across the continental margin.

  1. Geotherms and heat flow estimates in the Odra Fault Zone (NE margin of Bohemian Massif, Central Europe) and its relationships to geological structure of NE termination of the European Variscan Orogen (United States)

    Puziewicz, Jacek; Czechowski, Leszek; Majorowicz, Jacek; Pietranik, Anna; Grad, Marek


    The NE margin of Variscan Orogen in Europe comprises Sudety Mts., Fore-Sudetic Block, Odra Fault Zone and Fore-Sudetic Homocline. The Sudety Mts. together with the located to the NE Fore-Sudetic Block form NE part of the Bohemian Massif. The Variscan crystalline basement is exposed at the surface here. The Odra Fault Zone is situated further to the NE. It is a ca. 20 km wide horst of crystalline basement, hidden beneath relatively thin (thick Cenozoic sedimentary layer (Żelaźniewicz et al. 2016 and references therein). The Odra Horst is possibly a continuation of the Mid German Crystalline High at the NE side of the Bohemian Massif (Dörr et al. 2006). The copper mines located at the central part of the Odra Horst at depth 600 - 1000 m enable the numerous high-quality temperature measurements. However, complicated geometry of geological units requires 3D simulations. We use 3D numerical thermal model for the considered region. The heat flow in the region is 80 mW/m2 (corrected for paleclimate). This value is higher than in the neighbouring parts of Sudetes and Fore-Sudetic Block ( 70 mW/m2) and compares rather to positive heat flow anomaly stretching NW-SE in Wielkopolska region north of the Dolsk Fault and continuing to NE Germany. This anomaly corresponds crudely to the extent of the Permian volcanic province of Polish and North-East German Basin. Unfortunately, preliminary results of the model are not conclusive, because they depend on many parameters, (compare e.g. Puziewicz et al 2012). It remains an open question if this anomaly could be related to the lithospheric mantle thermal anomalies (Tesauro et al. 2009) or is rather due to crustal rock contributions. Funding. This study was possible thanks to the project NCN UMO-2014/15/B/ST10/00095 of Polish National Centre for Science to JP. Dörr W., Żelaźniewicz A., Bylina P., Schastok J., Franke W., Haack U., Kulicki C., 2006. Tournaisian age of granitoids from the Odra Fault Zone (southwestern Poland

  2. Detection of small earthquakes with dense array data: example from the San Jacinto fault zone, southern California (United States)

    Meng, Haoran; Ben-Zion, Yehuda


    We present a technique to detect small earthquakes not included in standard catalogues using data from a dense seismic array. The technique is illustrated with continuous waveforms recorded in a test day by 1108 vertical geophones in a tight array on the San Jacinto fault zone. Waveforms are first stacked without time-shift in nine non-overlapping subarrays to increase the signal-to-noise ratio. The nine envelope functions of the stacked records are then multiplied with each other to suppress signals associated with sources affecting only some of the nine subarrays. Running a short-term moving average/long-term moving average (STA/LTA) detection algorithm on the product leads to 723 triggers in the test day. Using a local P-wave velocity model derived for the surface layer from Betsy gunshot data, 5 s long waveforms of all sensors around each STA/LTA trigger are beamformed for various incident directions. Of the 723 triggers, 220 are found to have localized energy sources and 103 of these are confirmed as earthquakes by verifying their observation at 4 or more stations of the regional seismic network. This demonstrates the general validity of the method and allows processing further the validated events using standard techniques. The number of validated events in the test day is >5 times larger than that in the standard catalogue. Using these events as templates can lead to additional detections of many more earthquakes.

  3. A critical analysis of the long-term impact (1936-2015) of grazing management on Land Degradation in a marginal, rural community of Southern Italy (United States)

    Quaranta, Giovanni; Salvia, Rosanna; De Paola, Velia; Coluzzi, Rosa; Imbrenda, Vito; Simoniello, Tiziana


    Unsustainable grazing, one of the most diffused problem in land management at the global scale, is considered as a serious pressure on natural landscapes. Particularly in the Mediterranean agroforestry landscapes, unsustainable grazing is regarded as a key factor of degradation processes, mostly determined and exacerbated by evolving socioeconomic and environmental conditions at the local scale, revised agricultural policies and changing international market scenario. The Common Agricultural Policy set at the European level plays a powerful and twofold role in shaping the dynamics at local level. Measures adopted for Less Favoured Areas, for example, have stimulated grazing intensification based on financial supports whose effectiveness is shaped by the socioeconomic local context. At the same time, pasture-based livestock farming systems are considered priority habitats preserving traditional and high natural value farmlands in Mediterranean Europe. A sustainable management of pastures may also contribute to limit soil erosion and to mitigate land degradation. This paper critically analyses the drivers of change and the challenges facing a Mediterranean upland pastoralist systems in Southern Italy along a period of almost 80 years (1936-2015). The detailed case study highlights the linkages between the evolution of landscape, grazing management, locally adapted animal breeds and social capital. Historical forest maps, aerial imagery and satellite data at different spatial resolutions have been used to trace land use trajectories occurred during the investigated period within the study area. The integration in a GIS environment of the obtained results with diachronic detailed farm management surveys and semi-structured interviews, shows a strong link between land use changes and economic performances mainly connected to policy orientation. Along the time period considered, different adaptation strategies adopted by local actors are analysed leading to the present

  4. Slab geometry of the South American margin from joint inversion of body waves and surface waves (United States)

    Porritt, R. W.; Ward, K. M.; Porter, R. C.; Portner, D. E.; Lynner, C.; Beck, S. L.; Zandt, G.


    The western margin of South America is a long subduction zone with a complex, highly three -dimensional geometry. The first order structure of the slab has previously been inferred from seismicity patterns and locations of volcanoes, but confirmation of the slab geometry by seismic imaging for the entire margin has been limited by either shallow, lithospheric scale models or broader, upper mantle images, often defined on a limited spatial footprint. Here, we present new teleseismic tomographic SV seismic models of the upper mantle from 10°S to 40°S along the South American subduction zone with resolution to a depth of 1000 km as inferred from checkerboard tests. In regions near the Peru Bolivia border (12°S to 18°S) and near central Chile and western Argentina (29.5°S to 33°S) we jointly invert the multi-band direct S and SKS relative delay times with Rayleigh wave phase velocities from ambient noise and teleseismic surface wave tomography. This self-consistent model provides information from the upper crust to below the mantle transition zone along the western margin in these two regions. This consistency allows tracing the slab from the South American coastline to the sub-transition zone upper mantle. From this model we image several features, but most notable is a significant eastward step near the southern edge of the margin (24°-30° S). West of this step, a large high shear velocity body is imaged in the base of and below the transition zone. We suggest this may be a stagnant slab, which is descending into the lower mantle now that it is no longer attached to the surface. This suggests a new component to the subduction history of western South America when an older slab lead the convergence before anchoring in the transition zone, breaking off from the surface, and being overtaken by the modern, actively subducting slab now located further east.

  5. New Constraints on the Timing of Deformation in the Maberly Shear Zone, Southern Ontario, Canada from Electron Microprobe Dating of Monazite (United States)

    Markley, M. J.; Dunn, S. R.; Williams, M. L.; Jercinovic, M. J.


    The Maberly Shear Zone (MSZ) is a significant terrane boundary (sensu lato) within the Central Metasedimentary Belt of the Grenville Province of Southern Ontario, Canada. The MSZ juxtaposes the granulite-facies Frontenac Terrane to the southeast against the lower-grade Sharbot Lake Terrane to the northwest. The MSZ is characterized by a mylonitic foliation that dips moderately to steeply to the southeast and a stretching lineation that rakes to the east when it occurs. Rare kinematic indicators yield an ambiguous sense of shear. Previous workers infer that shearing along the MSZ occurred soon after Shawinigan events based on mineral cooling ages and because plutons yielding U/Pb zircon ages of 1180-1160 Ma occur in both neighboring terranes. We investigated monazite from a quartzo-feldspathic biotite-bearing straight gneiss that essentially represents the type locality of the shear zone (cropping out on route 7 just west of Maberly, Ontario, at Fall River crossing). This sample is the only one of a MSZ suite to yield monazite grains, and only five grains occur; other clots of concentrated lanthanide and actinide elements are likely retrogressed monazite. Most dates from the monazite grains are in the range 1160-1120 Ma, likely the timing of significant deformation accommodated by the MSZ. This interpretation is consistent with two previously published U/Pb titanite dates for the MSZ (even though these dates were tentatively interpreted as cooling ages). One monazite domain in our study, however, yielded a date of 1038 ± 10 Ma. Microstructural observations suggest that this domain is associated with reactivation of foliation in the MSZ. Although our results appear to confirm that the development of the MSZ directly postdated the Shawinigan orogeny, they also suggest that at least some deformation occurred in the MSZ during the Ottawan Orogeny, when this region was likely high in the orogenic pile and part of the Ottawan Orogenic Lid.

  6. Influence of growth regulator on plant growth, development and yield formation of sunflower hybrids (F1 under the conditions of Southern Steppe zone of Ukraine

    Directory of Open Access Journals (Sweden)

    О. А. Єременко


    Full Text Available Purpose. To study the effect of AKM plant growth regulator on growth, development and yield formation of sunflower (Helianthus annuus L. hybrids in hybridization plots under the conditions of the Southern Steppe zone of Ukraine. Methods. Laboratory tests, field study, statistical evaluation. Results. The results of studies devoted to determining the optimal AKM concentration for the treatment of seeds of the maternal and paternal lines, the effect of AKM on field germination, biometric parameters of sunflower plants, seed quality (F1 and yield are presented. Three hybrids of the Ukrainian selection, such as ‘Alpha’, ‘Logos’ and ‘Persei’ were studied during 2014–2016. Optimal concentration of AKM (0.0015 g/l was defined. The vigor of seeds processed by AKM was higher than in check variety by 0.8–12.8 р.р. (♂; 0.4–10.7 p.p. (♀, laboratory germination – by 2.3–6.1 p.p. (♂; 3.5–6.2 p.p. (♀. In 2016, the sunflower plant height for all variants exceeded this parameter to be obtained for other years of the study. This could be explained by the fact that HTC in 2016 for the BBCH 00–39 period was 1.4 times higher than in 2015. In general, hybrids as the studied factor considerably influenced sunflower yield, and the share of the hybrid (factor A influence is 33%. This should be considered when selecting hybrids for sunflower cultivation technologies in the Steppe zone of Ukraine. Conclusions. Hydrothermal conditions of the year had the maximum impact on the formation of seed quality and yield of sunflower plants of the hybrids under study, but when using AKM growth regulator for presowing seed treatment, this negative impact was reduced by an average of 23%.

  7. Stability of infant and child feeding index over time and its association with nutritional status of HIV exposed infants in Sidama Zone, Southern Ethiopia: a longitudinal study. (United States)

    Haile, Demewoz; Belachew, Tefera; Berhanu, Getenesh; Setegn, Tesfaye; Biadgilign, Sibhatu


    Even though many studies showed that infant and child feeding index has a statistically significant association with nutritional status, there is paucity of studies on stability of infant and child feeding index over time and its association with nutritional status of HIV exposed infants. This study aimed to investigate the stability of infant and child feeding index over time that is developed based on the current recommendations and its association with nutritional status of HIV exposed infants in Sidama Zone, Southern Ethiopia. A panel study design was conducted in health institutions in Sidama Zone from February to July, 2012. Three repeated measurements of data were collected from each HIV exposed infant aged 6-17 months over the 6 month follow-up period approximately per 2 month interval. The cross-sectional index was found stable overtime with the repeatability coefficient of 0.802 which differed significantly from zero (95% CI: 0.75-0.85). A longitudinal infant and child feeding index (L-ICFI) has a statistically significant association with length for age Z scores (LAZ) and weight for age Z scores (WAZ) at visit three (β=0.262, p=0.007; β=0.226, p=0.017), respectively. But the longitudinal index has no statistically significant association with WLZ score (p=0.552). There was no significant difference in change of LAZ and WAZ over time between L-ICFI tertiles for both female and male HIV exposed infants. The index is stable overtime at individual level even though one third of the index components were not stable. The L-CFI was associated with LAZ and WAZ but not with WLZ. However there was no significant difference in change of HAZ and WAZ over time between L-ICFI tertiles for both female and male HIV exposed infants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Factors controlling sedimentation in the Toruń-Eberswalde ice-marginal valley during the Pomeranian phase of the Weichselian glaciation: an overview (United States)

    Pisarska-Jamroży, Małgorzata


    During the Pleistocene the Scandinavian ice sheet drained huge quantities of sediment-laden meltwaters. These meltwaters supplied ice-marginal valleys that formed parallel to the front of the ice sheet. Not without significance was the supply of ice-marginal valleys from extraglacial rivers in the south. Moreover, periglacial conditions during and after sedimentation in ice-marginal valleys, the morphology of valley bedrocks, and erosion of older sediments played important roles in the depositional scenarios, and in the mineralogical composition of the sediments. The mechanisms that controlled the supply and deposition in ice-marginal valleys were analysed on the basis of a Pleistocene ice-marginal valley that was supplied by northern and southern source areas in the immediate vicinity. Investigations were conducted in one of the largest ice-marginal valleys of the Polish-German lowlands, i.e., the Toruń-Eberswalde ice-marginal valley, in sandurs (Drawa and Gwda) supplied sediments and waters from the north into this valley, and on extraglacial river terraces (pre-Noteć and pre-Warta rivers), formed simultaneously with the sandurs and ice-marginal valley (Pomeranian phase of Weichselian glaciation) supplied sediments and waters from the south into this valley. A much debated question is how similar, or different, depositional processes and sediments were that contributed to the formation of the Toruń-Eberswalde ice-marginal valley, and whether or not it is possible to differentiate mostly rapidly aggraded sandur sediments from ice-marginal valley sediments. Another question addresses the contribution of extraglacial feeding of the Toruń-Eberswalde ice-marginal valley. These matters were addressed by a wide range of analyses: sediment texture and structure, architectural elements of sediments, frequency of sedimentary successions, heavy-mineral analysis (both transparent and opaque heavy minerals), analysis of rounding and frosting of quartz grains, and

  9. Cattle-rangeland management practices and perceptions of pastoralists towards rangeland degradation in the Borana zone of southern Ethiopia. (United States)

    Solomon, T B; Snyman, H A; Smit, G N


    A survey was conducted in the Borana pastoral areas of southern Ethiopia to assess current livestock production systems, rangeland management practices and the perceptions of the pastoralists towards rangeland degradation. This information is considered vital to future pastoral development planning and interventions. Data were collected from a total of 20 villages that were identified from 5 peasant associations, namely Did Yabello, Moyatte, Did Harra, Dubuluk and Melbana. The average household size in the study area was 7.23. The majority of the pastoralists relied on both livestock and crop farming. The average livestock holding per household was 14 cattle, 10 goats, 6 sheep and 2 camels. Livestock holdings, with the exception of camels, has shown a declining trend over time. The two most important traditional rangeland management strategies adopted by the pastoralists included burning and mobility, but since 1974/75 burning has no longer been practised. With regard to mobility, the livestock herding falls in two categories, namely: home based and satellite herding. The former involves the herding of milking cows, calves and immature animals (2 years) further away from the encampments. Based on the pastoralists' perceptions, the major constraints on livestock production in descending order, were recurrent drought, feed and water scarcity, animal diseases, predators and communal land ownership. All the respondents considered the condition of the rangelands to have declined dramatically over time. In the past most development policies were based on equilibrium theories that opposed the communal use of the rangelands and traditional range management practices. The way in which the pastoral system affects the rangeland ecosystem functioning is contentious to this theory and the 'tragedy of the commons'. There was also a perceived problem of bush encroachment and the ban on traditional burning practices and recurrent droughts were seen as aggravating factors to this

  10. Crystallization and preliminary X-ray diffraction studies of the carbohydrate-recognition domain of SIGN-R1, a receptor for microbial polysaccharides and sialylated antibody on splenic marginal zone macrophages. (United States)

    Silva-Martin, Noella; Schauer, Joseph D; Park, Chae Gyu; Hermoso, Juan A


    SIGN-R1, or CD209b, is a mouse C-type lectin receptor that is expressed at high levels on macrophages in lymphoid tissues, especially within the marginal zone of the spleen. SIGN-R1 can bind and mediate the uptake of various microbial polysaccharides, including dextrans, lipopolysaccharides and pneumococcal capsular polysaccharides. It has been shown that SIGN-R1 mediates the clearance of encapsulated pneumococcus, complement fixation via binding C1q independent of antibody and innate resistance to pneumococcal infection. Recently, SIGN-R1 has also been demonstrated to bind sialylated antibody and mediate its activity to suppress autoimmunity. The carbohydrate-recognition domain (CRD) of SIGN-R1 has been cloned and overexpressed in a soluble secretory form in mammalian Chinese hamster ovary (CHO) cells. The CRD protein of SIGN-R1 was purified from CHO cell-culture supernatant and concentrated for crystallization using the hanging-drop vapour-diffusion method at 291 K. Crystals grew from a mixture of 2 M ammonium sulfate in 0.1 M bis-tris pH 5.5. Single crystals, which belonged to the monoclinic space group C2 with unit-cell parameters a = 146.72, b = 92.77, c = 77.06 A, beta = 121.66 degrees , allowed the collection of a full X-ray data set to a maximum resolution of 1.87 A.

  11. Eμ-BCL10 mice exhibit constitutive activation of both canonical and noncanonical NF-κB pathways generating marginal zone (MZ) B-cell expansion as a precursor to splenic MZ lymphoma (United States)

    Li, Zhaoyang; Wang, Hongsheng; Xue, Liquan; Shin, Dong-Mi; Roopenian, Derry; Xu, Wu; Qi, Chen-Feng; Sangster, Mark Y.; Orihuela, Carlos J.; Tuomanen, Elaine; Rehg, Jerold E.; Cui, Xiaoli


    BCL10, required for nuclear factor κB (NF-κB) activation during antigen-driven lymphocyte responses, is aberrantly expressed in mucosa-associated lymphoid tissue-type marginal zone (MZ) lymphomas because of chromosomal translocations. Eμ-driven human BCL10 transgenic (Tg) mice, which we created and characterize here, had expanded populations of MZ B cells and reduced follicular and B1a cells. Splenic B cells from Tg mice exhibited constitutive activation of both canonical and noncanonical NF-κB signaling pathways is associated with increased expression of NF-κB target genes. These genes included Tnfsf13b, which encodes the B-cell activating factor (BAFF). In addition, levels of BAFF were significantly increased in sera from Tg mice. MZ B cells of Tg mice exhibited reduced turnover in vivo and enhanced survival in vitro, indicative of lymphoaccumulation rather than lymphoproliferation as the cause of MZ expansion. In vivo antibody responses to both T-independent, and especially T-dependent, antigens were significantly reduced in Tg mice. Mortality was accelerated in Tg animals, and some mice older than 8 months had histologic and molecular findings indicative of clonal splenic MZ lymphoma. These results suggest that, in addition to constitutive activation of BCL10 in MZ B cells, other genetic factors or environmental influences are required for short latency oncogenic transformation. PMID:19696203

  12. Boiling and vertical mineralization zoning: a case study from the Apacheta low-sulfidation epithermal gold-silver deposit, southern Peru (United States)

    André-Mayer, Anne-Sylvie; Leroy, Jacques; Bailly, Laurent; Chauvet, Alain; Marcoux, Eric; Grancea, Luminita; Llosa, Fernando; Rosas, Juan


    The Au-Ag (±Pb-Zn) Apacheta deposit is located in the Shila district, 600 km southeast of Lima in the Cordillera Occidental of Arequipa Province, southern Peru. The vein mineralization is found in Early to Middle Miocene calc-alkaline lava flows and volcanic breccias. Both gangue and sulfide mineralization express a typical low-sulfidation system; assay data show element zoning with base metals enriched at depth and higher concentrations of precious metals in the upper part of the veins. Three main deposition stages are observed: (1) early pyrite and base-metal sulfides with minor electrum 1 and acanthite; (2) brecciation of this mineral assemblage and cross-cutting veinlets with subhedral quartz crystals, Mn-bearing calcite and rhombic adularia crystals; and finally (3) veinlets and geodal filling of an assemblage of tennantite/tetrahedrite + colorless sphalerite 2 + galena + chalcopyrite + electrum 2. Fluid inclusions in the mineralized veins display two distinct types: aqueous-carbonic liquid-rich Lw-c inclusions, and aqueous-carbonic vapor-rich Vw-c inclusions. Microthermometric data indicate that the ore minerals were deposited between 300 and 225 °C from relatively dilute hydrothermal fluids (0.6-3.4 wt% NaCl). The physical and chemical characteristics of the hydrothermal fluids show a vertical evolution, with in particular a drop in temperature and a loss of H2S. The presence of adularia and platy calcite and of co-existing liquid-rich and vapor-rich inclusions in the ore-stage indicates a boiling event. Strong H2S enrichment in the Vw-c inclusions observed at -200 m, the abundance of platy calcite, and the occurrence of hydrothermal breccia at this level may indicate a zone of intense boiling. The vertical element zoning observed in the Apacheta deposit thus seems to be directly related to the vertical evolution of hydrothermal-fluid characteristics. Precious-metal deposition mainly occurred above the 200-m level below the present-day surface, in response

  13. Breaking out of the comfort zone: El Niño-Southern Oscillation as a driver of trophic flows in a benthic consumer of the Humboldt Current ecosystem. (United States)

    Riascos, José M; Solís, Marco A; Pacheco, Aldo S; Ballesteros, Manuel


    The trophic flow of a species is considered a characteristic trait reflecting its trophic position and function in the ecosystem and its interaction with the environment. However, climate patterns are changing and we ignore how patterns of trophic flow are being affected. In the Humboldt Current ecosystem, arguably one of the most productive marine systems, El Niño-Southern Oscillation is the main source of interannual and longer-term variability. To assess the effect of this variability on trophic flow we built a 16-year series of mass-specific somatic production rate (P/B) of the Peruvian scallop (Argopecten purpuratus), a species belonging to a former tropical fauna that thrived in this cold ecosystem. A strong increase of the P/B ratio of this species was observed during nutrient-poor, warmer water conditions typical of El Niño, owing to the massive recruitment of fast-growing juvenile scallops. Trophic ecology theory predicts that when primary production is nutrient limited, the trophic flow of organisms occupying low trophic levels should be constrained (bottom-up control). For former tropical fauna thriving in cold, productive upwelling coastal zones, a short time of low food conditions but warm waters during El Niño could be sufficient to waken their ancestral biological features and display massive proliferations. © 2017 The Author(s).

  14. Intra-annual upwelling patterns and its linkage with primary production in the euphotic zone (24.5°N) of Southern Baja California coast (United States)

    Cervantes-Duarte, Rafael; Prego, Ricardo; Gaxiola-Castro, Gilberto; López-López, Silverio; Aguirre-Bahena, Fernando; Murillo-Murillo, Iban


    The continental shelf of Southern Baja California has been scarcely researched south of 25°N despite it being oceanographically necessary to gain a better understanding of the north-eastern Pacific transitional zone between middle and tropical latitudes. Therefore, the intra-annual patterns of the upwelling cycle and primary production were studied in a monitoring station (24.5°N, 112.1°W; 85 m depth) from August 2008 to December 2011. Monthly, thermohaline vertical profiles were recorded and seawater sampled at 100, 33, 10, 3 and 1% irradiance depth levels. Dissolved oxygen, nutrients and chlorophyll-a concentrations and net primary production (NPP, remote sensed and in situ) were determined. Two half-yearly recurrent periods (P < 0.001) were observed: an intense (cold) period from February to July and a faint (warm) period from August to January. In the euphotic layer, nitrate concentrations were inversely related to temperature, showing their dependence on upwelling. NPP was directly related to the upwelling process, with an annual average of 1.21 ± 0.81 gC m-2 d-1 in the triennium 2009-2011. Although the influence of La-Niña event was observed during the warm period of 2010 and the cold period of 2011, this change did not significantly affect NPP (P < 0.05).

  15. Volatiles in Olivine Hosted Melt Inclusions from Small Eruptive Centers of the Central Southern Volcanic Zone (CSVZ), Chile (United States)

    Wacaster, S.; Hickey-Vargas, R.; Wallace, P.


    This study is a geochemical analysis of basaltic scoria cones of the CSVZ, where bulk rock analyses have revealed two predominant lava types. We consider the relationship of cones to nearby stratovolcanos and the proximity of both to the Liquine-Ofqui Fault Zone to understand how primitive melts with wide ranging compositions are generated. We characterize melt inclusions to see if they show similar trends as bulk rocks and to evaluate degassing of melts during ascent and crystallization. We report new CO2, H2O, F, S, and Cl data collected by SIMS and FTIR. Type 1 and Type 2 lavas have been identified in prior studies. Type 1 rocks have significant 238U/232Th excesses and higher abundances of fluid mobile elements. Type 2 lavas and scorias have higher LREE/HREE ratios, lower abundances of fluid mobile elements, lower 87Sr/86Sr and U- series isotopes near secular equilibrium. Type 1, usually associated with composite volcanic centers, erupt at one cone in our field area, while Type 2 is found only at other individual cones aligned with the LOFZ. We characterize olivine-hosted melt inclusions with emphasis on volatile element analyses to test the hypotheses of flux melting beneath Type 1 centers versus a lesser extent of decompression melting beneath Type 2 centers. Melt inclusions show the following overall ranges of volatiles: CO2: below detection-1208 ppm; H2O(Total): 0.11-3.9 wt percent: F: 52-1442 ppm; S: 34-2884 ppm, and Cl: 177-1606 ppm. Inclusions from lavas are generally more degassed when compared to those from scoria for CO2 and H2O. Some Cl and F values are lower in inclusions from lavas, but not all. Sulfur is variably degassed in melt inclusions from both lavas and scoria. Melt inclusions from Type 2 Caburgua scoria show evidence for variable degassing and crystallization pressures. One subset of the inclusions were trapped at low pressures (P CO2 CO2 (1.5-4.0 wt % and 300-800 ppm and all under 1100 bars). Type I San Jorge melt inclusions also show

  16. Primary production and microbial activity in the euphotic zone of Lake Baikal (Southern Basin) during late winter (United States)

    Straškrábová, V.; Izmest'yeva, L. R.; Maksimova, E. A.; Fietz, S.; Nedoma, J.; Borovec, J.; Kobanova, G. I.; Shchetinina, E. V.; Pislegina, E. V.


    Three years of regular weekly/biweekly monitoring of seasonal changes in temperature, transparency, chlorophyll a (CHL) and bacteria [erythrosine-stained microscopic counts and cultivable colony forming units (CFUs)] at the vertical profile in the South basin of Lake Baikal (51°54'195″N, 105°04'235″E, depth 800 m) were evaluated. In more detail, the structure and function of phytoplankton and the microbial loop in the euphotic layer at the same site were investigated during the late-winter-early-spring period under the ice. The depth of euphotic zone (up to 1% of surface irradiation) was 35 to 40 m. Primary production was measured three times a week with the 14C method in 2, 10, 20, 30 and 40 m. Maximum production was found in 10 m, with lower values towards the surface (light inhibition) and towards the lower layers. The total production in cells larger than 1 μm in the column (0-40 m) was 204-240 mg C d -1 m -2, 30-40% of it being in cells 1-3 μm (mostly picocyanobacteria), which represented roughly 9% of the total chlorophyll a (estimated from pigment analyses). A major part of phytoplankton biomass was formed by diatoms ( Synedra acus Hust., Asterionella formosa Hass. and Stephanodiscus meyerii Genkal & Popovskaya). Total production (including extracellular, dissolved organic matter) was 235-387 mg C day -1 m -2, and the exudates were readily used by bacteria (particles 0.2-1 μm). This part amounted to 1-5% of cellular production in 2 to 20 m and 11-77% of cellular production in 20-40 m, i.e., in light-limited layers. From 0 to 30 m, chlorophyll a concentration was 0.8 to 1.3 μg l -1, wherefrom it decreased rapidly to 0.1 μg l -1 towards the depth of 40 m. Bacteria (DAPI-stained microscopic counts) reached 0.5-1.4×10 6 ml -1; their cell volumes measured via image analysis were small (average 0.05 μm -3), often not well countable when erythrosine stain was used. Bacterial biomasses were in the range of 6-21 μg C l -1. Numbers of colony forming

  17. Factors affecting women’s intention to use long acting and permanent contraceptive methods in Wolaita Zone, Southern Ethiopia: A cross-sectional study (United States)


    Background The use of long acting and permanent contraceptive methods (LAPMs) has not kept step with that of short-acting methods such as oral pills and injectable in Africa. This study explores the association between women’s awareness, attitude and barriers with their intention to use LAPMs among users of short term methods, in Southern Ethiopia. Methods A cross-sectional study design of mixed methods was conducted in the public health facilities of Wolaita zone, Southern Ethiopia, in January 2013. Women who were using short term contraceptive methods were the study population (n = 416). Moreover, 12 in-depth interviews were conducted among family planning providers and women who have been using short term methods. Data were entered into EPI Info version 3.5.3 and exported to SPSS version 16.0 for analysis. The odds ratios in the binary logistic regression model along with 95% confidence interval were used. Results One hundred fifty six (38%) of women had the intention to use LAPMs while nearly half of them (n = 216) had a negative attitude to use such methods. Moreover, two-third of study participants (n = 276) held myths and misconceptions about such methods. The women who had a positive attitude were found to be 2.5 times more intention to use LAPMs compared to women who had a negative attitude (AOR =2. 47; 95% CI: 1.48- 4.11). Women who had no myths and misconceptions on LAPMs were found to be 1.7 times more intention to use LAPMs compared to women who had myths and misconceptions (AOR = 1.71; 95% CI: 1.08- 2.72). Likewise, women who attained secondary and higher level of education were found to be 2 and 2.8 times more intention to use LAPMs compared to women with no education, respectively (AOR = 2. 10; 95% CI: 1.11- 3.98) and AOR = 2. 80; 95% CI: 1.15- 6.77). Conclusions Intention to use LAPMs was low and nearly half of women had a negative attitude to use such methods. Positive attitude, absence of myths and misconceptions on

  18. Factors affecting women's intention to use long acting and permanent contraceptive methods in Wolaita Zone, Southern Ethiopia: a cross-sectional study. (United States)

    Meskele, Mengistu; Mekonnen, Wubegzier


    The use of long acting and permanent contraceptive methods (LAPMs) has not kept step with that of short-acting methods such as oral pills and injectable in Africa. This study explores the association between women's awareness, attitude and barriers with their intention to use LAPMs among users of short term methods, in Southern Ethiopia. A cross-sectional study design of mixed methods was conducted in the public health facilities of Wolaita zone, Southern Ethiopia, in January 2013. Women who were using short term contraceptive methods were the study population (n = 416). Moreover, 12 in-depth interviews were conducted among family planning providers and women who have been using short term methods. Data were entered into EPI Info version 3.5.3 and exported to SPSS version 16.0 for analysis. The odds ratios in the binary logistic regression model along with 95% confidence interval were used. One hundred fifty six (38%) of women had the intention to use LAPMs while nearly half of them (n = 216) had a negative attitude to use such methods. Moreover, two-third of study participants (n = 276) held myths and misconceptions about such methods. The women who had a positive attitude were found to be 2.5 times more intention to use LAPMs compared to women who had a negative attitude (AOR =2. 47; 95% CI: 1.48- 4.11). Women who had no myths and misconceptions on LAPMs were found to be 1.7 times more intention to use LAPMs compared to women who had myths and misconceptions (AOR = 1.71; 95% CI: 1.08- 2.72). Likewise, women who attained secondary and higher level of education were found to be 2 and 2.8 times more intention to use LAPMs compared to women with no education, respectively (AOR = 2. 10; 95% CI: 1.11- 3.98) and AOR = 2. 80; 95% CI: 1.15- 6.77). Intention to use LAPMs was low and nearly half of women had a negative attitude to use such methods. Positive attitude, absence of myths and misconceptions on LAPMs and secondary and plus level of

  19. Assessing acid rain and climate effects on the temporal variation of dissolved organic matter in the unsaturated zone of a karstic system from southern China (United States)

    Liao, Jin; Hu, Chaoyong; Wang, Miao; Li, Xiuli; Ruan, Jiaoyang; Zhu, Ying; Fairchild, Ian J.; Hartland, Adam


    Acid rain has the potential to significantly impact the quantity and quality of dissolved organic matter (DOM) leached from soil to groundwater. Yet, to date, the effects of acid rain have not been investigated in karstic systems, which are expected to strongly buffer the pH of atmospheric rainfall. This study presents a nine-year DOM fluorescence dataset from a karst unsaturated zone collected from two drip sites (HS4, HS6) in Heshang Cave, southern China between 2005 and 2014. Cross-correlograms show that fluorescence intensity of both dripwaters lagged behind rainfall by ∼1 year (∼11 months lag for HS4, and ∼13 months for HS6), whereas drip rates responded quite quickly to rainfall (0 months lag for HS4, and ∼3 months for HS6), based on optimal correlation coefficients. The rapid response of drip rates to rainfall is related to the change of reservoir head pressure in summer, associated with higher rainfall. In winter, low rainfall has a limited effect on head pressure, and drip rates gradually slow to a constant value associated with base flow from the overlying reservoir- this effect being most evident on inter-annual timescales (R2 = 0.80 for HS4 and R2 = 0.86 for HS6, n = 9, p water and solute transport. After eliminating the one year lag, the congruent seasonal pacing and amplitude between fluorescence intensity and rainfall observed suggests that the seasonality of fluorescence intensity was mainly controlled by the monsoonal rains which can govern the output of DOM from the soil, as well as the residence time of water in the unsaturated zone. On inter-annual timescales, a robust linear relationship between fluorescence intensity and annual (effective) precipitation amount (R2 = 0.86 for HS4 and R2 = 0.77 for HS6, n = 9, p < 0.01) was identified, implying that annual (effective) precipitation is the main determinant of DOM concentration in the aquifer. Conversely, the insensitivity of fluorescence intensity and fluorescence wavelength maxima to

  20. Trends of tuberculosis case notification and treatment outcomes in the Sidama Zone, southern Ethiopia: ten-year retrospective trend analysis in urban-rural settings. (United States)

    Dangisso, Mesay Hailu; Datiko, Daniel Gemechu; Lindtjørn, Bernt


    Ethiopia is one of the high tuberculosis (TB) burden countries. An analysis of trends and differentials in case notifications and treatment outcomes of TB may help improve our understanding of the performance of TB control services. A retrospective trend analysis of TB cases was conducted in the Sidama Zone in southern Ethiopia. We registered all TB cases diagnosed and treated during 2003-2012 from all health facilities in the Sidama Zone, and analysed trends of TB case notification rates and treatment outcomes. The smear positive (PTB+) case notification rate (CNR) increased from 55 (95% CI 52.5-58.4) to 111 (95% CI 107.4-114.4) per 105 people. The CNRs of PTB+ in people older than 45 years increased by fourfold, while the mortality of cases during treatment declined from 11% to 3% for smear negative (PTB-) (X2trend, P<0.001) and from 5% to 2% for PTB+ (X2trend, P<0.001). The treatment success was higher in rural areas (AOR 1.11; CI 95%: 1.03-1.2), less for PTB- (AOR 0.86; CI 95%: 0.80-0.92) and higher for extra-pulmonary TB (AOR 1.10; CI 95%: 1.02-1.19) compared to PTB+. A higher lost-to-follow up was observed in men (AOR 1.15; CI 95%: 1.06-1.24) and among PTB- cases (AOR 1.14; CI 95%: 1.03-1.25). More deaths occurred in PTB-cases (AOR 1.65; 95% CI: 1.44-1.90) and among cases older than 65 years (AOR 3.86; CI 95%: 2.94-5.10). Lastly, retreatment cases had a higher mortality than new cases (6% vs 3%). Over the past decade TB CNRs and treatment outcomes improved, whereas the disparities of disease burden by gender and place of residence reduced and mortality declined. Strategies should be devised to address higher risk groups for poor treatment outcomes.

  1. Trends of tuberculosis case notification and treatment outcomes in the Sidama Zone, southern Ethiopia: ten-year retrospective trend analysis in urban-rural settings.

    Directory of Open Access Journals (Sweden)

    Mesay Hailu Dangisso

    Full Text Available Ethiopia is one of the high tuberculosis (TB burden countries. An analysis of trends and differentials in case notifications and treatment outcomes of TB may help improve our understanding of the performance of TB control services.A retrospective trend analysis of TB cases was conducted in the Sidama Zone in southern Ethiopia. We registered all TB cases diagnosed and treated during 2003-2012 from all health facilities in the Sidama Zone, and analysed trends of TB case notification rates and treatment outcomes.The smear positive (PTB+ case notification rate (CNR increased from 55 (95% CI 52.5-58.4 to 111 (95% CI 107.4-114.4 per 105 people. The CNRs of PTB+ in people older than 45 years increased by fourfold, while the mortality of cases during treatment declined from 11% to 3% for smear negative (PTB- (X2trend, P<0.001 and from 5% to 2% for PTB+ (X2trend, P<0.001. The treatment success was higher in rural areas (AOR 1.11; CI 95%: 1.03-1.2, less for PTB- (AOR 0.86; CI 95%: 0.80-0.92 and higher for extra-pulmonary TB (AOR 1.10; CI 95%: 1.02-1.19 compared to PTB+. A higher lost-to-follow up was observed in men (AOR 1.15; CI 95%: 1.06-1.24 and among PTB- cases (AOR 1.14; CI 95%: 1.03-1.25. More deaths occurred in PTB-cases (AOR 1.65; 95% CI: 1.44-1.90 and among cases older than 65 years (AOR 3.86; CI 95%: 2.94-5.10. Lastly, retreatment cases had a higher mortality than new cases (6% vs 3%.Over the past decade TB CNRs and treatment outcomes improved, whereas the disparities of disease burden by gender and place of residence reduced and mortality declined. Strategies should be devised to address higher risk groups for poor treatment outcomes.

  2. Assessment of the Impacts of Climate Change on Maize Production in the Southern and Western Highlands Sub-agro Ecological Zones of Tanzania

    Directory of Open Access Journals (Sweden)

    Philbert M. Luhunga


    Full Text Available The Intergovernmental Panel on Climate Change (IPCC fourth assessment report confirmed that climate change is unequivocal. It is coming to us faster with larger impacts and bigger risks than even most climate scientists expected as recently as a few years ago. One particular worry is the disastrous consequence to agriculture and food security sectors in many parts of the world, particularly in developing countries. Adaptation is the only option to reduce the impacts of climate change. However, before planning adaptation policies or strategies to climate change, it is important to assess the impacts of climate change at regional and local scale to have scientific evidence that would guide the formulation of such policies or strategies. In this study the impacts of climate change on rain-fed maize (Zea Mays production in the southern and western highlands sub-agro ecological zones of Tanzania are evaluated. High resolution climate simulations from the Coordinated Regional Climate Downscaling Experiment_Regional Climate Models (CORDEX_RCMs were used as input into the Decision Support System for Agro-technological Transfer (DSSAT to simulate maize yield in the historical climate condition (1971–2000, present (2010–2039, mid (2040–2069, and end (2070–2099 centuries. Daily rainfall, solar radiations, minimum and maximum temperatures for the historical (1971–2000 climate condition and future climate projections (2010–2099 under two Representative Concentration Pathways (RCPs RCP4.5 and RCP 8.5 were used to drive DSSAT. The impacts of climate change were assessed by comparing the average maize yields in historical climate condition against the average of simulated maize yields in the present, mid and end centuries under RCP4.5 and RCP8.5. Results of future maize yields estimates from DSSAT driven by individual RCMs under both RCP scenarios (RCP 4.5 and RCP 8.5 differs from one RCM to another and from one scenario to another. This highlight

  3. Hydration of an active shear zone: Interactions between deformation, metasomatism and magmatism - the spinel-lherzolites from the Montferrier (southern France) Oligocene basalts

    Energy Technology Data Exchange (ETDEWEB)

    Cabanes, N.; Briqueu, L.


    Geochemical and textural investigations have been simultaneously performed on spinel-lherzolite xenoliths from the Oligo-Miocene alkali basalts of Montferrier (southern France). All the investigated samples have undergone a deformation very particular by intense shearing under high stresses (up to 1.75 kbar), low temperatures (less than or equal to900/sup 0/C) and strain rates of about 10/sup -18/ to 10/sup -15/ s/sup -1/. Mineral chemistry reveals that the Montferrier lherzolites are fragments of an undepleted relatively shallow upper mantle level located at a depth of 50 km (15 kbar). Moreover, Na and Ti enrichment in diopside would reflect a metasomatic event, also emphasized by the common occurrence of pargasite in 50-70% of the investigated samples. Crystallization of this amphibole is attributed to a hydrous infiltration which is related in time and space to the deformation. Indeed, amphibole is preferentially concentrated in strongly deformed zones and in kink-band boundaries of orthopyroxene porphyroclasts. Moreover, the grain boundaries were used by the pervasive agent to percolate into the lherzolite: significant chemical variations (increase in MgO: 15% and decrease in Al/sub 2/O/sub 3/: 55%) are observed within the range of 7-5 adjacent to the grain boundary. Finally, Sr isotopic data (/sup 87/Sr//sup 86/Sr) demonstrate that the amphibole, i.e. the metasomatic agent, is genetically related to the host lava of the xenoliths. Thus, the hydrous silicate liquid from which the amphibole has crystallized may be an early percolation of the ascending alkali magma.

  4. Lateglacial-Holocene abrupt vegetation changes at Lago Trifoglietti in Calabria, Southern Italy: The setting of ecosystems in a refugial zone (United States)

    Beaulieu, Jacques-Louis de; Brugiapaglia, Elisabetta; Joannin, Sébastien; Guiter, Frédéric; Zanchetta, Giovanni; Wulf, Sabine; Peyron, Odile; Bernardo, Liliana; Didier, Julien; Stock, Agnès; Rius, Damien; Magny, Michel


    Retrospective science such as palaeoecology deeply depends on the preservation of archives in sensitive places. As an example, mountains of medium altitude from Mediterranean peninsulas have long been identified by biogeographers as refuges zones allowing the survival of European temperate taxa during the ice ages, but archives to validate this hypothesis are scarce, especially in Southern Italy. Here we present a new sequence from Lago Trifoglietti (1048 m a.s.l.) in the Calabrian Mountains, which covers the Late Glacial Interstadial (LGI, corresponding to the Bölling-Alleröd period in northern-central Europe) and the transition to the Holocene. The independent chronology based on seven radiocarbon dates is supported by the evidence of three tephra layers already identified in other regional sequences. During the LGI, besides the high diversity of non arboreal pollen grains, a great number of pollens of temperate forest trees are present or abundant (mostly deciduous oaks and fir). These assemblages suggest that the site was above but not far from the upper limit of diversified woodland stands. They confirm a local survival during the last glacial. The Younger Dryas is not marked by major changes, and oak percentages are even higher, suggesting a resilient expansion at lower altitude. Surprisingly the site remains above the timberline until an aridity crisis centered at 11,100 cal 14C yr PB, which is correlated with the Preboreal Oscillation (PBO). This event is immediately followed by the local settlement of a dense fir and beech forest around the lake. A comparison with other Italian key sequences aims at explaining the climate forcing factors that governed this original vegetation dynamic. Further investigations using additional proxies are needed for a more robust climate reconstruction.

  5. Timing of Deformation in the Central Metasedimentary Belt Boundary Thrust Zone (CMBbtz), southern Ontario, Canada, from Electron Microprobe Dating of Monazite (United States)

    Markley, M. J.; Dunn, S. R.; Peck, W. H.; Jercinovic, M. J.; Williams, M. L.


    In the Grenville Province of Southern Ontario, the Central Metasedimentary Belt boundary thrust zone (CMBbtz) is a crustal-scale tectonic boundary between the older, granulite-facies Central Gneiss Belt to the NW and the younger, amphibolite-facies Central Metasedimentary Belt to the SE. Although there are a range of tectonic models for the CMBbtz, most workers agree it is a major tectonic boundary that accommodated ductile thrusting and crustal shortening during the Ottawan phase of the Grenville Orogeny (~1080-1020 Ma). Some studies suggest that ductile thrusting in the CMBbtz was roughly synchronous with synorogenic extensional collapse below an orogenic lid. Previous geochronological studies also provide evidence of earlier deformation and/or metamorphic events in the CMBbtz, although the relation between deformation in the CMBbtz to the Elzeviran (~1230 Ma) and Shawinigan (~1180 Ma) orogenies is unclear. Our study is the first to report in situ electron microprobe monazite (mnz) dates from amphibolite-grade ortho- and para-gneisses of the CMBbtz. Our results are broadly consistent with other chronometers. We present dates from 132 age-domains within 83 mnz grains in 14 samples. Although our data provide strong evidence for deformation and metamorphism along the length of the CMBbtz during the Ottawan (1080-1020 Ma), we also report two other clusters of ages: 1140-1110 Ma and 1230-1170 Ma. The latter cluster falls between the widely accepted ranges for the Elzeviran and Shawinigan orogenies. In addition, some individual outcrops, particularly those in Killaloe and Minden, show mnz ages spanning over 200 m.y., and the setting and compositions of individual monazite domains allow us to link mnz growth to episodes of garnet growth during multiple events. Together these data indicate an unexpectedly continuous and long-lived period of deformation and metamorphism in the CMBbtz.

  6. Variations in magmatic processes along the East Greenland volcanic margin (United States)

    Voss, Max; Schmidt-Aursch, Mechita C.; Jokat, Wilfried


    Seismic velocities and the associated thicknesses of rifted and igneous crust provide key constraints on the rifting history, the differentiation between non-volcanic and volcanic rifted margins, the driving force of magmatism at volcanic margins, that is, active or passive upwelling and the temperature anomaly in the lithosphere. This paper presents two new wide-angle seismic transects of the East Greenland margin and combines the velocity models with a compilation of 30-wide-angle seismic velocity models from several publications along the entire East Greenland margin. Compiled maps show the depth to basement, depth to Moho, crustal thickness and thickness of high velocity lower crust (HVLC; with velocities above 7.0 km s-1). First, we present two new wide-angle seismic transects, which contribute to the compilation at the northeast Greenland margin and over the oceanic crust between Shannon Island and the Greenland Fracture Zone. Velocity models, produced by ray tracing result in total traveltime rms-misfits of 100-120 milliseconds and χ2 values of 3.7 and 2.3 for the northern and southern profiles with respect to the data quality and structural complexity. 2-D gravity modelling is used to verify the structural and lithologic constraints. The northernmost profile, AWI-20030200, reveals a magma starved break-up and a rapidly thinning oceanic crust until magnetic anomaly C21 (47.1 Ma). The southern seismic transect, AWI-20030300, exhibits a positive velocity anomaly associated with the Shannon High, and a basin of up to 15 km depth beneath flood basalts between Shannon Island and the continent-ocean boundary. Break-up is associated with minor crustal thickening and a rapidly decreasing thickness of oceanic crust out to anomaly C21. The continental region is proposed to be only sparsely penetrated by volcanism and not underplated by magmatic material at all compared to the vast amount of magmatism further south. Break-up is proposed to have occurred at the seaward

  7. Age and duration of intra-oceanic arc volcanism built on a suprasubduction zone type oceanic crust in southern Neotethys, SE Anatolia

    Directory of Open Access Journals (Sweden)

    Fatih Karaoğlan


    Full Text Available The southeastern Anatolia comprises numbers of tectono-magmatic/stratigraphic units such as the metamorphic massifs, the ophiolites, the volcanic arc units and the granitoid rocks. All of them play important role for the late Cretaceous evolution of the southern Neotethys. The spatial and temporal relations of these units suggest the progressive development of coeval magmatism and thrusting during the late Cretaceous northward subduction/accretion. Our new U-Pb zircon data from the rhyolitic rocks of the wide-spread volcanic arc unit show ages of (83.1 ± 2.2–(74.6 ± 4.4 Ma. Comparison of the ophiolites, the volcanic arc units and the granitoids suggest following late Cretaceous geological evolution. The ophiolites formed in a suprasubduction zone (SSZ setting as a result of northward intra-oceanic subduction. A wide-spread island-arc tholeiitic volcanic unit developed on the top of the SSZ-type crust during 83–75 Ma. Related to regional plate convergence, northward under-thrusting of SSZ-type ophiolites and volcanic arc units was initiated beneath the Tauride platform (Malatya-Keban and followed by the intrusion of I-type calc-alkaline volcanic arc granitoids during 84–82 Ma. New U-Pb ages from the arc-related volcanic-sedimentary unit and granitoids indicate that under-thrusting of ophiolites together with the arc-related units beneath the Malatya-Keban platform took place soon after the initiation of the volcanic arc on the top of the SSZ-type crust. Then the arc-related volcanic-sedimentary unit continued its development and lasted at ∼75 Ma until the deposition of the late Campanian–Maastrichtian shallow marine limestone. The subduction trench eventually collided with the Bitlis-Pütürge massif giving rise to HP-LT metamorphism of the Bitlis massif. Although the development of the volcanic arc units and the granitoids were coeval at the initial stage of the subduction/accretion both tectono-magmatic units were

  8. Knowledge of obstetric danger signs and associated factors among pregnant women attending antenatal care at health facilities of Yirgacheffe town, Gedeo zone, Southern Ethiopia. (United States)

    Hibstu, Desalegn Tsegaw; Siyoum, Yadeshi Demisse


    Obstetric danger signs are not the literal obstetric complications, merely symptoms that are well named by non-clinical personnel. The identification of these danger signs and its relation with complications during pregnancy would increase the capacity of women, their partners and families to seek for timely health care, following the appropriate steps to insure a safe birth and post-partum. The aim of this study was to assess the knowledge of obstetric danger signs and associated factors among pregnant women attending antenatal care in Yirgacheffe town, Gedeo zone, Southern Ethiopia. Institutional-based cross-sectional study was conducted from March 15-April 15, 2016. Data on pregnant women were collected using a pre-tested and interviewer administered structured questionnaire from 342 women using systematic random sampling technique. Bivariate and multivariate logistic regression was performed using SPSS version 20.0 software. A total of 342 (90%) pregnant women were included in the study. The level of obstetric knowledge of danger signs was 21.9% (95% CI: 20.2-55.65%). Maternal education (AOR = 0.26, CI: 0.08, 0.88), paternal education (AOR = 0.13, CI; 0.04, 04) and time taken to reach health facilities on foot (AOR = 0.06, CI: 0.02, 0.17) were negatively associated factors while maternal age (AOR = 3.68, CI: 1.30, 10.46), paternal occupation (AOR = 4.65, CI: 1.82, 11.87), place of residence (AOR = 2.61, CI: 1.35, 5.04) were positively associated factors with knowledge of obstetric danger signs. Maternal and paternal education, maternal age, paternal occupation, place of residence and time taken to reach health facility on foot were the main factors for knowledge of obstetric danger signs. Increasing knowledge of key danger signs, creating and promoting income generating mechanisms need to be continuously done at the health facility and the community as it makes ready women and their families for prompt and appropriate decisions and measures in case

  9. Prevalence and factors associated with trachoma among children aged 1–9 years in Zala district , Gamo Gofa zone, Southern Ethiopia

    Directory of Open Access Journals (Sweden)

    Mengistu K


    Full Text Available Kassahun Mengistu1 Mulugeta Shegaze2 Kifle Woldemichael3 Hailay Gesesew3,4 Yohannes Markos5 1Department of Zonal Health Office, Gamo Goffa Zone, Arba Minch, Ethiopia; 2Department of Nursing, Arba Minch University, Arba Minch, Ethiopia; 3Department of Epidemiology, Jimma University, Jimma, Ethiopia; 4Discipline of Public Health, Flinders University, Adelaide, Australia; 5Department of Medical Physiology, Jimma University, Jimma, Ethiopia Background: Trachoma is the leading cause of preventable blindness worldwide. It is common in areas where people are socioeconomically deprived. Globally, approximately 1.2 billion people live in trachoma-endemic areas, in which, 40.6 million individuals have active trachoma and 8.2 million have trichiasis. According to the World Health Organization’s 2007 report, globally close to 1.3 million people are blind due to trachoma, while approximately 84 million suffer from active trachoma. The National Survey (2007 of Ethiopia showed a prevalence of 40.1% active trachoma among children aged 1–9 years. Trachoma is still endemic in most parts of Ethiopia.Objective: To assess prevalence of trachoma and factors associated with it among children aged 1–9 years in Zala district, Gamo Gofa Zone, Southern Nations, Nationalities, and Peoples’ Region.Methods: A community-based cross-sectional study was conducted in Zala district from February 28 to March 26, 2014. A total of 611 children were examined for trachoma based on the simplified World Health Organization 1983 classification. A multistage stratified sampling technique with a systematic random sampling technique was used to select study participants. Data were collected by using a semistructured pretested questionnaire and clinical eye examination. The data were entered using EpiData version 3.1 and analyzed using SPSS version 16. Multivariable logistic regression analysis was used to identify independently associated factors.Results: The overall prevalence of

  10. Polyphase Rifting and Breakup of the Central Mozambique Margin (United States)

    Senkans, Andrew; Leroy, Sylvie; d'Acremont, Elia; Castilla, Raymi


    from strike-slip deformation localised along a proposed crustal weakness, represented by the Lurio-Pebane shear zone. A more north-south oriented extension is recorded by the continental breakup and oceanisation. A failed rift is initially formed between the Beira High and the African continent followed by the successful rifting of its southern margin. This study proposes a segmentation of the Central Mozambique margin, with oceanisation first occurring in the Angoche segment. The formation of the first oceanic crust in the Beira segment followed, likely delayed by the formation and failure of the northern Beira High rift. *The PAMELA project (PAssive Margin Exploration Laboratories) is a scientific project led by Ifremer and TOTAL in collaboration with Université Rennes 1, Université Pierre and Marie Curie, Université de Bretagne Occidentale, CNRS and IFPEN.

  11. Anomalous heat flow belt along the continental margin of Brazil (United States)

    Hamza, Valiya M.; Vieira, Fabio P.; Silva, Raquel T. A.


    A comprehensive analysis of thermal gradient and heat flow data was carried out for sedimentary basins situated in the continental margin of Brazil (CMB). The results point to the existence of a narrow belt within CMB, where temperature gradients are higher than 30 °C/km and the heat flow is in excess of 70 mW/m2. This anomalous geothermal belt is confined between zones of relatively low to normal heat flow in the adjacent continental and oceanic regions. The width of the belt is somewhat variable, but most of it falls within the range of 100-300 km. The spatial extent is relatively large in the southern (in the basins of Pelotas, Santos and Campos) and northern (in the basins of Potiguar and Ceará) parts, when compared with those in the central parts (in the basins of South Bahia, Sergipe and Alagoas). The characteristics of heat flow anomalies appear to be compatible with those produced by thermal sources at depths in the lower crust. Hence, magma emplacement at the transition zone between lower crust and upper mantle is considered the likely mechanism producing such anomalies. Seismicity within the belt is relatively weak, with focal depths less than 10 km for most of the events. Such observations imply that "tectonic bonding" between continental and oceanic segments, at the transition zone of CMB, is relatively weak. Hence, it is proposed that passive margins like CMB be considered as constituting a type of plate boundary that is aseismic at sub-crustal levels, but allows for escape of significant amounts of earth's internal heat at shallow depths.

  12. Superposition of structures in the interference zone between the southern Brasília belt and the central Ribeira belt in the region SW of Itajubá (MG, SE Brazil

    Directory of Open Access Journals (Sweden)

    Rodrigo Vinagre

    Full Text Available ABSTRACT: The study area is localized in the Socorro nappe, part of the southern Brasília belt, with a minor part in the Embu terrane, part of the central Ribeira belt. Three phases of deformation were detected, Dn-1, Dn and Dn+1. Sn-1 seems to be generally transposed into Sn, but in the northwestern part it is well preserved, dipping about 60º to W and SW, with a stretching and/or mineral lineation plunging down dip. The main foliation in most of the area is Sn, dipping about 70º to SSE. Dn folds are tight to isoclinal, with axes that plunge about 40º to SW. Quartz-feldspathic segregation veins are folded by Dn. The structures related to Dn-1 and Dn are cut and modified by four important shear zones ascribed to deformation phase Dn+1. Two samples of a granite that is elongated along the Caxambu shear zone, and also cut by it, were dated. One yielded a crystallization age of 575 ± 5 Ma, and the other one, from the shear zone, an age of 567 ± 8 Ma, interpreted either as representing the age of movement along the Caxambu shear zone, or as metamorphic growth.

  13. Marginalization and health geomatics. (United States)

    Alexander, Gregory L; Kinman, Edward L; Miller, Louise C; Patrick, Timothy B


    Marginalized groups have been defined as groups that have been peripheralized from the center of society. Increasing nursing knowledge of marginalized groups and the dynamics of population diversity will enable nurses to better recognize shifting health patterns, plan for utilization of health services, and determine ethnic and cultural differences that exist in marginalized populations. The authors of this article review theoretical models responsible for defining the concept marginalization, describe geographical information systems as a recommended tool to evaluate marginalized groups, and provide a case study utilizing tools and maps as a means of assessing marginal situations.

  14. 40Ar/39Ar ages (600-570 Ma of the Serra do Azeite transtensional shear zone: evidence for syncontractional extension in the Cajati area, southern Ribeira belt

    Directory of Open Access Journals (Sweden)

    Rômulo Machado


    Full Text Available This paper presents 40Ar/39Ar ages of the rocks from the Serra do Azeite transtensional shear zone in the southern part of the Ribeira belt, between the States of São Paulo and Paraná, and also discusses the regional correlations and the tectonic implications for other parts of the belt. The geochronological data suggest that transtensional deformation was active between 600 and 580 Ma (hornblende and muscovite apparent ages, respectively. This time span is considerably older than previous proposals for the period of activity of these structures (520-480 Ma in the northern segment of this belt and in the Araçuaí belt. Kinematic analysis of the dated mylonites shows extensional structures with top-down movement to ESE compatible with structures found in other tectonic segments in the eastern portion of the Quadrilátero Ferrífero and in the Rio Doce Valley region. Our ages are situated in the same time interval defined for the alkaline magmatism of the Serra do Mar suite. We suggest that the regional tectonic framework was developed during continental-scale extension. This process has been coeval with convergent strain in the adjacent Neoproterozoic shear zones of the Apiaí/Ribeira and Araçuaí belts, which make up significant segments of these belts. The available data show that these structures may not be simply related to post-orogenic gravitational collapse, but must involve a more complex process probably related to dynamic balance between crustal thickening and thinning during tectonic convergence, basin formation and exhumation processes.Este trabalho apresenta idades 40Ar/39Ar de rochas da Zona de Cisalhamento Transtrativa Sinistral da Serra do Azeite, situada na parte sul do cinturão Ribeira, entre os Estados de São Paulo e Paraná, bem como discute a correlação regional e as implicações tectônicas com outras partes do cinturão. Os dados geocronológicos sugerem que a deformação extensional foi ativa entre 600 e 580 Ma

  15. Transport accidents among children and adolescents at the emergency service of a teaching hospital in the southern zone of the city of São Paulo☆☆☆ (United States)

    Gorios, Carlos; de Souza, Renata Maia; Gerolla, Viviane; Maso, Bruno; Rodrigues, Cintia Leci; Armond, Jane de Eston


    Objective to describe the victim profile and circumstances of transport accidents involving children and adolescents who were attended at a teaching hospital in the southern zone of the city of São Paulo. Methods this was an individual observational case series study among patients up to the age of 19 years who were attended at a hospital in the southern zone of the city of São Paulo, state of São Paulo, Brazil, due to traffic accidents. The files notifying suspected or confirmed cases of violence and accidents (SIVVA files) covering January to December 2012 were analyzed. Results among the 149 cases notified, 64.4% related to males and 35.6% to females. The transport accidents were predominantly among males, irrespective of age. The main injury diagnoses were superficial head trauma (24.8%) followed by multiple non-specified trauma (36.4%), in both sexes. Conclusion transport accidents among children and adolescents occurred more often among males. The main transport accidents among the children and adolescents attended as emergency cases were caused by motor vehicles and motorcycles. Among the accident victims, the largest proportion was attended because of being run over. PMID:26229833

  16. Punctuated Neogene tectonics and stratigraphy of the African-Iberian plate-boundary zone: concurrent development of Betic-Rif basins (southern Spain, northern Morocco)

    NARCIS (Netherlands)

    Sissingh, W.


    This paper integrates the sequence stratigraphic and tectonic data related to the Neogene geodynamic and palaeogeographic development of the African-Iberian plate boundary zone between Spain and Morocco. Though the dating of individual tectonostratigraphic sequences and their delimiting sequence

  17. Geoelectrical behavior of a Fault Zone: the meaning of the electrical resistivity of metric-scale segments of the Liquiñe-Ofqui and the Arc-oblique Long-lived Fault Systems, Southern Andes (United States)

    Roquer, T.; Arancibia, G.; Yanez, G. A.; Estay, N.; Rowland, J. V.; Figueroa, R.; Iturrieta, P. C.


    The geoelectrical behavior of blind fault zones has been studied by different authors at decametric-to-kilometric scales, and inferred to reveal the dimensions of the main structural domains of a fault zone (core vs. damage zone). However, there is still a lack in the application of electrical methods in exposed fault zones, despite the importance of validating the inferences based on electrical measurements with direct geologic observation. In this study we correlate the results of structural mapping and geoelectrical measurements in two metric-scale, very well exposed segments of the Liquiñe-Ofqui Fault System (LOFS) and the Arc-oblique Long-lived Fault System (ALFS), Southern Andes. The LOFS is an active dextral and dextral-normal ca. 1200-km-long Cenozoic intra-arc structure that strikes NNE to NE. Although the LOFS and the ALFS cross-cut each other, the ALFS is an apparently older basement NW-striking fault system where mainly sinistral movement is recorded. Two 22-m-long transects were mapped revealing in both examples a simple core and an assymetric damage zone with more frequency of fractures in the hanging wall than in the footwall. The LOFS outcrop showed a WNW-striking, 65°S-dipping core; the ALFS, a NW-striking, 60°SW-dipping core. A 2D direct-current electrical survey was made at each locality, orthogonal to the respective strike of the core. The field installation of the electrical survey used two electrode configurations for each outcrop: (1) electrodes were put in a vertical wall of rock, which gives a resistivity profile in plan view; and (2) electrodes were put in the ground, which gives a cross-section resistivity profile. The combined structural and electrical results suggest that: (1) it is possible to discriminate the geoelectrical response of the main metric-scale structural domains: the core and the fractured damage zones are relative conductors (20-200 ohm-m), whereas the less fractured damage zones are relative resistive volumes (500

  18. A biodiversidade bentônica em lagoa marginal ao rio Paranapanema na zona de sua desembocadura, na represa de Jurumirim - DOI: 10.4025/actascibiolsci.v28i4.166 The benthic biodiversity in a lake marginal to the Paranapanema river in its mouth zone into Jurumirim reservoir- DOI: 10.4025/actascibiolsci.166

    Directory of Open Access Journals (Sweden)

    Rosemary Cristina Souza Davanso


    Full Text Available O presente trabalho teve como objetivo principal verificar a biodiversidade bentônica em áreas do fundo da lagoa do Coqueiral, zona de desembocadura do rio Paranapanema, na represa de Jurumirim, Estado de São Paulo. Foram selecionados dezoito pontos de amostragem, englobando áreas rasas e áreas profundas. As coletas foram feitas em intervalos trimestrais ao longo de um ano; também foram analisadas as variáveis físicas e químicas da água (nível, transparência, temperatura, oxigênio dissolvido, pH e condutividade elétrica. Amostras do sedimento, para análise da fauna e de fatores abióticos (granulometria e conteúdo orgânico, foram recolhidas em tréplicas, utilizando como coletor a draga de Petersen. O material foi triado e analisado sob microscópio estereoscópico. Contagem e identificação dos organismos foram realizadas, e densidade, abundância relativa, riqueza taxonômica e índice de dominância foram calculados. A análise revelou uma fauna com baixa diversidade e a dominância de Chironomidae e Ephemeroptera. Domínio de Ephemeroptera, constituído por Campsurus, ocorreu no período mais quente do ano e com baixa profundidade da lagoa. A distribuição dos organismos teve como principais fatores determinantes profundidade, transparência, pH e temperatura da água. Na comparação feita entre áreas rasas e profundas, foi observada uma menor densidade de organismos nas regiões profundas.Coqueiral lake is a marginal lake located at the southeast São Paulo State, in the mouth zone of the Paranapanema river into Jurumirim Reservoir and it has high connectivity with the Paranapanema river. This work aimed to verify the benthic biodiversity in areas of the lake bottom. 18 sampling sites in the lake were selected, including shallow and deep areas. The samples were taken every three months during one year. Physical and chemical water variables (level, transparency, dissolved oxygen, pH, and electric conductivity were

  19. Environment, agriculture, and settlement patterns in a marginal Polynesian landscape (United States)

    Kirch, P.V.; Hartshorn, A.S.; Chadwick, O.A.; Vitousek, P.M.; Sherrod, D.R.; Coil, J.; Holm, L.; Sharp, W.D.


    Beginning ca. A.D. 1400, Polynesian farmers established permanent settlements along the arid southern flank of Haleakala Volcano, Maui, Hawaiian Islands; peak population density (43-57 persons per km2) was achieved by A.D. 1700-1800, and it was followed by the devastating effects of European contact. This settlement, based on dryland agriculture with sweet potato as a main crop, is represented by >3,000 archaeological features investigated to date. Geological and environmental factors are the most important influence on Polynesian farming and settlement practices in an agriculturally marginal landscape. Interactions between lava flows, whose ages range from 3,000 to 226,000 years, and differences in rainfall create an environmental mosaic that constrained precontact Polynesian farming practices to a zone defined by aridity at low elevation and depleted soil nutrients at high elevation. Within this productive zone, however, large-scale agriculture was concentrated on older, tephra-blanketed lava flows; younger flows were reserved for residential sites, small ritual gardens, and agricultural temples.

  20. The winter pack-ice zone provides a sheltered but food-poor habitat for larval Antarctic krill


    Meyer, Bettina; Freier, Ulrich; Grimm, Volker; Groeneveld, Jürgen; Hunt, Brian P. V.; Kerwath, Sven; King, Rob; Klaas, Christine; Pakhomov, Evgeny A.; Meiners, Klaus M.; Melbourne-Thomas, Jessica; Murphy, Eugene J.; Thorpe, Sally E.; Stammerjohn, Sharon; Wolf-Gladrow, Dieter


    A dominant Antarctic ecological paradigm suggests that winter sea ice is generally the main feeding ground for krill larvae. Observations from our winter cruise to the southwest Atlantic sector of the Southern Ocean contradict this view and present the first evidence that the pack-ice zone is a food-poor habitat for larval development. In contrast, the more open marginal ice zone provides a more favourable food environment for high larval krill growth rates. We found that complex under-ice ha...

  1. The Links Between the Formation of the Gulf of Mexico and the Late Proterozoic to Mesozoic Tectonic Evolution of Southern North America (United States)

    Keller, G. R.; Mickus, K. L.; Gurrola, H.; Harry, D. L.; Pulliam, J.


    A full understanding of the Gulf of Mexico's geologic history depends on understanding the tectonic framework along the southern margin of North America. The first step in establishing this framework was the breakup of Laurentia during the Early Paleozoic. At least one tectonic block rifted away from Laurentia's southern margin at this time, and is interpreted to be presently located in Argentina. Rifting resulted in a sinuous margin consisting of alternating ridge and transform segments extending from the southeastern U.S. across Texas into northern Mexico. The Paleozoic margin is associated with a clearly defined gravity high, and ends in the trend of this high are associated with intersections of ridge and transform segments along the margin. By the end of the Paleozoic, continental assembly via the Appalachian-Ouachita orogeny added new terranes to the eastern and southern margins of Laurentia and the assembly of the supercontinent Pangea was complete. Triassic through Late Jurassic opening of the Gulf of Mexico (GOM) created a complex margin, initially mobilizing several crustal blocks that were eventually left behind on the North American margin as seafloor spreading developed within the Gulf and the Yucatan block separated and rotated into its current position. Recent deep seismic reflection profiles along the northern margin of the GOM show that rifted continental crust extends offshore for 250 km before the oceanic crust of the Gulf of Mexico is encountered. Our group has worked to produce four integrated models of the lithospheric structure based upon reflection, refraction, and teleseismic data acquired across this margin integrated with gravity, magnetic, geologic and drilling data. These models define a complex zone of crustal thinning along the Gulf Coastal plain of Texas that is covered by up to 10km of primarily Cretaceous and younger sedimentary rocks. To the east along the coastal plain region, we have defined two large crustal blocks that were

  2. Morpholithodynamical changes of the beach and the nearshore zone under the impact of submerged breakwaters – a case study (Orłowo Cliff, the Southern Baltic

    Directory of Open Access Journals (Sweden)

    Agnieszka Kubowicz-Grajewska


    Based on the conducted research and analysis, it has been found that the construction has a minor impact on the modification of the shore and nearshore zone morpholithodynamics, which is evidenced by a sinuate shape of the shoreline and a relatively stable cape in the central part of the area, present both before (1966–2005 and after SBWs were built. Furthermore, the progressive abrasion, the lack of significant changes in the morphology and particle size distribution of the beach and the nearshore zone, as well as the fact that those changes are limited only to the immediate surroundings of the submerged breakwaters prove their neutral impact.

  3. Assessment of Biomass Resources from Marginal Lands in APEC Economies

    Energy Technology Data Exchange (ETDEWEB)

    Milbrandt, A.; Overend, R. P.


    The goal of this study is to examine the marginal lands in Asia-Pacific Economic Cooperation (APEC) economies and evaluate their biomass productivity potential. Twelve categories of marginal lands are identified using the Global Agro-Ecological Zones system of the United Nations Food and Agriculture Organization.

  4. Simple shear detachment fault system and marginal grabens in the southernmost Red Sea rift (United States)

    Tesfaye, Samson; Ghebreab, Woldai


    The NNW-SSE oriented Red Sea rift, which separates the African and Arabian plates, bifurcates southwards into two parallel branches, southeastern and southern, collectively referred to as the southernmost Red Sea rift. The southern branch forms the magmatically and seismo-tectonically active Afar rift, while the less active southeastern branch connects the Red Sea to the Gulf of Aden through the strait of Bab el Mandeb. The Afar rift is characterized by lateral heterogeneities in crustal thickness, and along-strike variation in extension. The Danakil horst, a counterclockwise rotating, narrow sliver of coherent continental relic, stands between the two rift branches. The western margin of the Afar rift is marked by a series of N-S aligned right-lateral-stepping and seismo-tectonically active marginal grabens. The tectonic configuration of the parallel rift branches, the alignment of the marginal grabens, and the Danakil horst are linked to the initial mode of stretching of the continental crust and its progressive deformation that led to the breakup of the once contiguous African-Arabian plates. We attribute the initial stretching of the continental crust to a simple shear ramp-flat detachment fault geometry where the marginal grabens mark the breakaway zone. The rift basins represent the ramps and the Danakil horst corresponds to the flat in the detachment fault system. As extension progressed, pure shear deformation dominated and overprinted the initial low-angle detachment fault system. Magmatic activity continues to play an integral part in extensional deformation in the southernmost Red Sea rift.

  5. Marginalization of the Youth

    DEFF Research Database (Denmark)

    Jensen, Niels Rosendal


    The article is based on a key note speach in Bielefeld on the subject "welfare state and marginalized youth", focusing upon the high ambition of expanding schooling in Denmark from 9 to 12 years. The unintended effect may be a new kind of marginalization.......The article is based on a key note speach in Bielefeld on the subject "welfare state and marginalized youth", focusing upon the high ambition of expanding schooling in Denmark from 9 to 12 years. The unintended effect may be a new kind of marginalization....

  6. Zone of Nigeria

    African Journals Online (AJOL)

    Affected by Fertilizer in the Southern Guinea Savanna. Zone of Nigeria ... soybean varieties and the requirement by the exotic varieties ... Deficiencies of nitrogen and phosphorus ... maize at the time of sowing soybean. Maize ..... when cut open were pinkish red in colour. 56 ..... release from root of alfalfa and soybean grown.

  7. Temporal variation on environmental variables and pollution indicators in marine sediments under sea Salmon farming cages in protected and exposed zones in the Chilean inland Southern Sea. (United States)

    Urbina, Mauricio A


    The impacts of any activity on marine ecosystems will depend on the characteristics of the receptor medium and its resilience to external pressures. Salmon farming industry develops along a constant gradient of hydrodynamic conditions in the south of Chile. However, the influence of the hydrodynamic characteristics (weak or strong) on the impacts of intensive salmon farming is still poorly understood. This one year study evaluates the impacts of salmon farming on the marine sediments of both protected and exposed marine zones differing in their hydrodynamic characteristics. Six physico-chemical, five biological variables and seven indexes of marine sediments status were evaluated under the salmon farming cages and control sites. Our results identified a few key variables and indexes necessary to accurately evaluate the salmon farming impacts on both protected and exposed zones. Interestingly, the ranking of importance of the variables and the temporality of the observed changes, varied depending on the hydrodynamic characteristics. Biological variables (nematodes abundance) and environmental indexes (Simpson's dominance, Shannon's diversity and Pielou evenness) are the first to reflect detrimental impacts under the salmon farming cages. Then the physico-chemical variables such as redox, sulphurs and phosphorus in both zones also show detrimental impacts. Based on the present results we propose that the hydrodynamic regime is an important driver of the magnitude and temporality of the effects of salmon farming on marine sediments. The variables and indexes that best reflect the effects of salmon farming, in both protected and exposed zones, are also described. Copyright © 2016. Published by Elsevier B.V.

  8. Mineralogical constraint for metamorphic conditions in a shear zone affecting the Archean Ngoulemakong tonalite, Congo craton (Southern Cameroon) and retentivity of U-Pb SHRIMP zircon dates (United States)

    Tchameni, R.; Lerouge, C.; Penaye, J.; Cocherie, A.; Milesi, J. P.; Toteu, S. F.; Nsifa, N. E.


    In the Ngoulemakong region of the Ntem unit (South Cameroon), tonalite crops out as intrusions of various sizes cross-cutting the charnockite suite. Both of these granitoids are affected by NE-SW and WNW-ESE sinistral and dextral shear zones. Tonalite in the WNW-ESE shear zone are deformed and shows metamorphic assemblages represented by quartz-microcline-biotite-garnet-plagioclase-scapolite-fluoro-apatite and chlorite-sulfides-epidote-muscovite-quartz-calcite not recorded by the undeformed rocks outside it. These mineralogical assemblages provide evidence of decreasing pressure-temperature conditions from granulite-amphibolite-facies in the moderate deformed part to greenschist-facies in the central part of the shear plane. The higher fluid (H 2O, CO 2, S, F, Cl, K, and Na) activities and high-grade recrystallizations recorded in the shear zone favour a Pb loss hypothesis in the zircons. U-Pb SHRIMP zircon dating yield an emplacement age of 2865 ± 4 Ma for the tonalite but does not permit the determination of the age of the high-grade event responsible for the Pb loss. These results provide evidence of the retentivity of U-Pb zircon dates under high grade conditions.

  9. Upper triassic continental margin strata of the central alaska range: Implications for paleogeographic reconstruction (United States)

    Till, A.B.; Harris, A.G.; Wardlaw, B.R.; Mullen, M.


    Remnants of a Late Triassic continental margin and ocean basin are scattered across central and southern Alaska. Little is known about the fundamental nature of the margin because most remnants have not been studied in detail and a protracted period of terrane accretion and margin-parallel translation has disrupted original stratigraphic and structural relationships.

  10. Effect of Biochar Application on Growth of Garden Pea (Pisum sativum L.) in Acidic Soils of Bule Woreda Gedeo Zone Southern Ethiopia


    Berihun, Tariku; Tolosa, Shiferaw; Tadele, Muluken; Kebede, Firew


    The aim of this experiment was to study the effect of types and rates of biochar on growth, yield, and yield component of garden pea at Bule wereda, Southern Ethiopia. The treatments consist of two types of biochar (corncobs and Lantana camara) and four rates of biochar (0, 6, 12, and 18 t ha−1). The experiment was laid out as a randomized complete block design in a factorial arrangement with three replications. Soil samples were collected at a depth of 0–30 cm and germination parameter and p...

  11. The influence of air-sea-ice interactions on an anomalous phytoplankton bloom in the Indian Ocean sector of the Antarctic Zone of the Southern Ocean during the austral summer, 2011 (United States)

    Sabu, P.; Anilkumar, N.; George, Jenson V.; Chacko, Racheal; Tripathy, S. C.; Achuthankutty, C. T.


    An anomalous phytoplankton bloom was recorded in the Indian Ocean sector of the Antarctic Zone (AZ) of the Southern Ocean (SO) during the austral summer, 2011. Possible mechanisms for the triggering of such a large bloom were analyzed with the help of in situ and satellite data. The bloom, which formed in January 2011, intensified during February and weakened by March. High surface chlorophyll (Chl) concentrations (0.76 mg m-3) were observed in the area of the bloom (60°S, 47°E) with a Deep Chlorophyll Maximum (DCM) of 1.15 mg m-3 at a depth of 40-60 m. During 2011, both the concentration and spatial extent of sea ice were high on the western side of the bloom, between 0°E and 40°E, and enhanced freshwater influx was observed in the study area as a result of melting ice. A positive Southern Annular Mode (SAM) (with a resultant northward horizontal advection) and an intense La Niña during 2010-2011 are possible reasons for the high sea-ice concentrations. The enhanced Chl a observed in the study region, which can be attributed to the phytoplankton bloom, likely resulted from the influx of nutrient-laden freshwater derived from melting sea ice.

  12. Turbidite event history--Methods and implications for Holocene paleoseismicity of the Cascadia subduction zone (United States)

    Goldfinger, Chris; Nelson, C. Hans; Morey, Ann E.; Johnson, Joel E.; Patton, Jason R.; Karabanov, Eugene; Gutierrez-Pastor, Julia; Eriksson, Andrew T.; Gracia, Eulalia; Dunhill, Gita; Enkin, Randolph J.; Dallimore, Audrey; Vallier, Tracy; Kayen, Robert; Kayen, Robert


    Turbidite systems along the continental margin of Cascadia Basin from Vancouver Island, Canada, to Cape Mendocino, California, United States, have been investigated with swath bathymetry; newly collected and archive piston, gravity, kasten, and box cores; and accelerator mass spectrometry radiocarbon dates. The purpose of this study is to test the applicability of the Holocene turbidite record as a paleoseismic record for the Cascadia subduction zone. The Cascadia Basin is an ideal place to develop a turbidite paleoseismologic method and to record paleoearthquakes because (1) a single subduction-zone fault underlies the Cascadia submarine-canyon systems; (2) multiple tributary canyons and a variety of turbidite systems and sedimentary sources exist to use in tests of synchronous turbidite triggering; (3) the Cascadia trench is completely sediment filled, allowing channel systems to trend seaward across the abyssal plain, rather than merging in the trench; (4) the continental shelf is wide, favoring disconnection of Holocene river systems from their largely Pleistocene canyons; and (5) excellent stratigraphic datums, including the Mazama ash and distinguishable sedimentological and faunal changes near the Pleistocene-Holocene boundary, are present for correlating events and anchoring the temporal framework. Multiple tributaries to Cascadia Channel with 50- to 150-km spacing, and a wide variety of other turbidite systems with different sedimentary sources contain 13 post-Mazama-ash and 19 Holocene turbidites. Likely correlative sequences are found in Cascadia Channel, Juan de Fuca Channel off Washington, and Hydrate Ridge slope basin and Astoria Fan off northern and central Oregon. A probable correlative sequence of turbidites is also found in cores on Rogue Apron off southern Oregon. The Hydrate Ridge and Rogue Apron cores also include 12-22 interspersed thinner turbidite beds respectively. We use 14C dates, relative-dating tests at channel confluences, and

  13. The Rovuma Transform Margin: the enigmatic continent-ocean boundary of East Africa (United States)

    Phethean, Jordan; Kalnins, Lara; van Hunen, Jeroen; McCaffrey, Ken; Davies, Richard


    The N-S trending Davie Fracture Zone (DFZ) is often assumed to form the continent-ocean transform margin (COTM) of the Western Somali Basin. However, multiple plate tectonic reconstructions favour a pre-breakup location for Madagascar that crosses the DFZ, incompatible with its interpretation as the COTM (e.g., Lottes & Rowley, 1990; Reeves, 2014; Phethean et al., 2016). For the first time, we have identified classic COTM features in seismic reflection data from the Southern Rovuma Basin, to the west and inboard of the DFZ. These suggest a NNW trend to the margin, consistent with the tectonic reconstructions. 2D gravity models, with the seabed and top basement constrained by seismic data, are used to investigate the Moho structure across the Rovuma margin and are best fit using steep 'transform style' geometries, confirming the nature of the margin. We thus model generic COTM geometries elsewhere along the East African and Madagascan transform margins to locate best-fitting positions for these conjugate COTMs. This analysis confirms that the COTMs follow a NNW trend along the Rovuma Basin and Southern Madagascar, respectively, and allows a restoration of the conjugate COTMs. This restoration is used alongside geological maps and satellite imagery from Madagascar and East Africa to refine early plate motions and further constrain the precise origin of Madagascar within Gondwana. Our refined plate tectonic model independently predicts major observations made from seismic reflection and gravity data across the basin, including: regions of major transpression/transtension along the DFZ, merging of fracture zones to form the DFZ, oceanic crust on either side of the DFZ and within the Tanzania coastal basin, and the location of an abandoned MOR within the Tanzania coastal basin. We believe that this study finally provides conclusive evidence that Madagascar originated from within the Tanzania Coastal Basin, inboard of the DFZ, after some 30 years of debate regarding this

  14. Transform continental margins - part 1: Concepts and models (United States)

    Basile, Christophe


    This paper reviews the geodynamic concepts and models related to transform continental margins, and their implications on the structure of these margins. Simple kinematic models of transform faulting associated with continental rifting and oceanic accretion allow to define three successive stages of evolution, including intra-continental transform faulting, active transform margin, and passive transform margin. Each part of the transform margin experiences these three stages, but the evolution is diachronous along the margin. Both the duration of each stage and the cumulated strike-slip deformation increase from one extremity of the margin (inner corner) to the other (outer corner). Initiation of transform faulting is related to the obliquity between the trend of the lithospheric deformed zone and the relative displacement of the lithospheric plates involved in divergence. In this oblique setting, alternating transform and divergent plate boundaries correspond to spatial partitioning of the deformation. Both obliquity and the timing of partitioning influence the shape of transform margins. Oblique margin can be defined when oblique rifting is followed by oblique oceanic accretion. In this case, no transform margin should exist in the prolongation of the oceanic fracture zones. Vertical displacements along transform margins were mainly studied to explain the formation of marginal ridges. Numerous models were proposed, one of the most used is being based on thermal exchanges between the oceanic and the continental lithospheres across the transform fault. But this model is compatible neither with numerical computation including flexural behavior of the lithosphere nor with timing of vertical displacements and the lack of heating related to the passing of the oceanic accretion axis as recorded by the Côte d'Ivoire-Ghana marginal ridge. Enhanced models are still needed. They should better take into account the erosion on the continental slope, and the level of coupling

  15. Practical Marginalized Multilevel Models (United States)

    Griswold, Michael E.; Swihart, Bruce J.; Caffo, Brian S.; Zeger, Scott L.


    Clustered data analysis is characterized by the need to describe both systematic variation in a mean model and cluster-dependent random variation in an association model. Marginalized multilevel models embrace the robustness and interpretations of a marginal mean model, while retaining the likelihood inference capabilities and flexible dependence structures of a conditional association model. Although there has been increasing recognition of the attractiveness of marginalized multilevel models, there has been a gap in their practical application arising from a lack of readily available estimation procedures. We extend the marginalized multilevel model to allow for nonlinear functions in both the mean and association aspects. We then formulate marginal models through conditional specifications to facilitate estimation with mixed model computational solutions already in place. We illustrate the MMM and approximate MMM approaches on a cerebrovascular deficiency crossover trial using SAS and an epidemiological study on race and visual impairment using R. Datasets, SAS and R code are included as supplemental materials. PMID:24357884

  16. Deep structure and historical earthquakes in the Calabrian subduction zone (Southern Italy): preliminary results from multi-channel seismic reflection profiles (United States)

    Gallais, F.; Gutscher, M.; Torelli, L.; Polonia, A.; Riminucci, F.


    The Calabrian subduction zone is located in the complex Central Mediterranean area. This subduction is characterized by the presence of deep earthquakes under the Tyrrhenian Sea down to 500 km depth. The Tethyan remnant Ionian slab descends towards the NW at a dip of about 70° and is associated with an active volcanic arc (the Aeolian Islands). Recently reported GPS and seismicity studies suggest that the subduction of the Ionian lithosphere beneath the Calabrian Arc may be locally still active, though at very slow rates (thrust earthquakes, characteristic of active subduction zone, suggests that if subduction is active, the fault plane may be locked since the instrumental period. To seek evidence of continuous tectonic activity of the Calabrian system, we present preliminary results from reprocessed 96-channels seismic reflection profiles (French Archimede cruise, 1997) offshore Sicily. This analysis permits to recognize a well-defined stratigraphy in the Ionian Abyssal Plain, this stratigraphy becomes difficult to follow under the deformed Calabrian Prism. But the joint interpretation with the reprocessed PM01 profile (French PRISMED cruise, 1994) helps constrain this interpretation and to image some characteristic structures of an accretionary wedge (fore/back-thrusts, basal decollement...). This study also include interpretation of a more recent Italian seismic cruise (Calamare, 2008) and CROP profiles. This work will help to prepare a future cruise proposal (CIRCEE, to be submitted in January 2010) to study the Calabrian subduction with OBS, MCS seismic, heat-flow measurements and sediment coring. The goals are : 1/ to image the deep structure of this subduction zone, 2/ to characterize its thermal state to deduce a geometry of the seismogenic part of the plate interface and add new constraints on seismic risk linked with the Calabrian subduction.

  17. Quantification of the surface brackish water layer and frontal zones in southern Chilean fjords between Boca del Guafo (43°30‧S) and Estero Elefantes (46°30‧S) (United States)

    Calvete, Carolina; Sobarzo, Marcus


    The southern Chilean region between the Boca del Guafo passage and Estero Elefantes contains one of the estuarine zones with the greatest freshwater influence on the planet. At the surface, plumes of freshwater from the fjord heads to their mouths, emptying into the Moraleda-Costa-Elefantes channel system and then the coastal ocean. The influence of this freshwater on the region's estuarine dynamics, coastal ecology, and biogeochemical processes has only recently begun to be elucidated. Using hydrographic data from the CIMAR-Fiordos cruises (1998-2001), this study quantifies the equivalent height of freshwater, emphasizing the role it plays in the potential energy anomaly and front locations, as well as its relationship with river discharges. Using a criterion of equivalent height of freshwater >15% (density Elefantes), with horizontal extensions on the order of 100 km. The limits of this layer tended to coincide with frontal zones having potential energy anomaly gradients >0.005 J/m 4. The frontal zones were located in the extreme southeast of Jacaf Channel, at the head of Ventisquero Sound, in the central part of the Puyuguapi and Moraleda channels, and at the head and mouth of Aysén Fjord. The equivalent height of freshwater and potential energy anomaly showed a good correlation with the accumulated (5-day) river discharges ( r2=0.87), which were greatest toward the fjord heads in spring. The brackish surface water had short residence times (3.5 days) in Aysen Fjord, unlike the deep layer, which other authors report to have a longer residence time (near 1 year).

  18. Terminal suturing of Gondwana along the southern margin of South China Craton : evidence from detrital zircon U-Pb ages and Hf isotopes in Cambrian and Ordovician strata, Hainan Island


    Xu, Y; Cawood, P.A.; Du, Y; Zhong, Z.; Hughes, N.C.


    This work was supported by the National Natural Science Foundation of China (grants 41472086 and 41272120), “111” Project (B08030), the fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) (CUG2012019240 and CUG2013019137). The first author also acknowledges China Scholarship Council (grant 201208420001) for supporting his research in the University of St. Andrews. Date of Acceptance: 20/11/2014 Hainan Island, located near the southern end of mai...

  19. Paleomagnetism, rock magnetism and opaque mineralogy of iron ore deposits from southern Mexico and their implications for quantitative modelling of magnetometric data

    Energy Technology Data Exchange (ETDEWEB)

    Alva-Valdivia, L.M.; Fucugauchi, Urrutia, J.; Bohnel, H.; Moran Zenteno, D.J. (Universidad Nacional Autonoma de Mexico, Mexico City (Mexico))


    Paleomagnetism, Rock Magnetism and Opaque Mineralogy of Iron Ore Deposits from Southern Mexico and Their Implications for Quantitative Modelling of Magnetometric Data. The tectonic history of the Pacific continental margin is critical for understanding their mineral deposits. The margin presents intrusive and volcanic activity characteristic of magmatic arcs of subduction zones, which are genetically related with deposits of Cu, Fe, Mo, Au, and Ag. Although the tectonic history has been complex, involving oblique plate subduction, lateral movements, accretion of magmatic arcs and oceanic plateaux, and lateral displacements of major blocks, the mineral deposits are spatially distributed along elongated belts that roughly follow the margin. The authors have conducted paleomagnetic, rock magnetic, and petrological studies of the iron ore deposits to investigate genesis, magnetic mineralogy, stratigraphic relationships, metamorphism, and applications on quantitative modelling of magnetometric data. The remanent magnetization and susceptibility data are necessary for interpretation of magnetic anomalies. The results permit a comparison of the mineral deposits along the continental margin.

  20. Result of alpha track detection of radon in soil gas in the Khlong Marui Fault Zone, Southern Thailand: A possible earthquake precursor

    Directory of Open Access Journals (Sweden)

    Tripob Bhongsuwan


    Full Text Available Measurements of radon concentration in soil gas were conducted at ten stations (ST1-ST10, located mainly in theKhlong Marui Fault Zone, Thap Put District, Phang Nga Province over a period from 28 January to 25 April, 2007. The resultsof the radon concentration were presented as the variation of cumulative alpha track over a week period. At Station ST10 theradon concentrations are in general higher than those at other stations for every week. Two significant radon anomalies werefound to have the concentration above the mean value plus one standard deviation. During the period of monitoring thelocal and regional earthquake activities were observed showing patterns consistent with the occurrence of the radon anomalies.The maximum radon concentration is interpreted to be related to a possible influence of the pressure and stress increasedin the subsurface. An increase in the number of earthquakes is observed correlating to a lower radon concentration when thesubsurface pressure dropped due to tectonic stress release by seismic activities. Therefore, it would be possible to use thevariation of soil gas radon concentration as an earthquake precursor in the Khlong Marui Fault Zone.

  1. Analysis of ice shelf flexure and its InSAR representation in the grounding zone of the southern McMurdo Ice Shelf (United States)

    Rack, Wolfgang; King, Matt A.; Marsh, Oliver J.; Wild, Christian T.; Floricioiu, Dana


    We examine tidal flexure in the grounding zone of the McMurdo Ice Shelf, Antarctica, using a combination of TerraSAR-X repeat-pass radar interferometry, a precise digital elevation model, and GPS ground validation data. Satellite and field data were acquired in tandem between October and December 2014. Our GPS data show a horizontal modulation of up to 60 % of the vertical displacement amplitude at tidal periods within a few kilometres of the grounding line. We ascribe the observed oscillatory horizontal motion to varying bending stresses and account for it using a simple elastic beam model. The horizontal surface strain is removed from nine differential interferograms to obtain precise bending curves. They reveal a fixed (as opposed to tidally migrating) grounding-line position and eliminate the possibility of significant upstream bending at this location. The consequence of apparent vertical motion due to uncorrected horizontal strain in interferometric data is a systematic mislocation of the interferometric grounding line by up to the order of one ice thickness, or several hundred metres. While our field site was selected due to its simple boundary conditions and low background velocity, our findings are relevant to other grounding zones studied by satellite interferometry, particularly studies looking at tidally induced velocity changes or interpreting satellite-based flexure profiles.

  2. Analysis of ice shelf flexure and its InSAR representation in the grounding zone of the southern McMurdo Ice Shelf

    Directory of Open Access Journals (Sweden)

    W. Rack


    Full Text Available We examine tidal flexure in the grounding zone of the McMurdo Ice Shelf, Antarctica, using a combination of TerraSAR-X repeat-pass radar interferometry, a precise digital elevation model, and GPS ground validation data. Satellite and field data were acquired in tandem between October and December 2014. Our GPS data show a horizontal modulation of up to 60 % of the vertical displacement amplitude at tidal periods within a few kilometres of the grounding line. We ascribe the observed oscillatory horizontal motion to varying bending stresses and account for it using a simple elastic beam model. The horizontal surface strain is removed from nine differential interferograms to obtain precise bending curves. They reveal a fixed (as opposed to tidally migrating grounding-line position and eliminate the possibility of significant upstream bending at this location. The consequence of apparent vertical motion due to uncorrected horizontal strain in interferometric data is a systematic mislocation of the interferometric grounding line by up to the order of one ice thickness, or several hundred metres. While our field site was selected due to its simple boundary conditions and low background velocity, our findings are relevant to other grounding zones studied by satellite interferometry, particularly studies looking at tidally induced velocity changes or interpreting satellite-based flexure profiles.

  3. Recent progress in Pacific-Asian Marginal Seas (PAMS) studies (United States)

    Matsuno, Takeshi; Hirose, Naoki; Zhang, Jing; Cho, Yang-Ki; Chen, Dake; Yuan, Dongliang; Hung, Chin-Chang; Jan, Sen


    Marginal seas which represent the buffer zones between land and the pelagic ocean are being increasingly influenced by human activity. The role of the marginal seas is important for many reasons, among which are biological resources and climate change. In East Asia, we have marginal seas between the Asian Continent and the Pacific Ocean, where various countries and areas form complicated territories and EEZ. To understand the marine environment of marginal seas, international cooperative scientific activities are necessary, and it is essential to share the latest information and knowledge.

  4. Factors controlling sedimentation in the Toruń-Eberswalde ice-marginal valley during the Pomeranian phase of the Weichselian glaciation: an overview

    Directory of Open Access Journals (Sweden)

    Pisarska-Jamroży Małgorzata


    Full Text Available During the Pleistocene the Scandinavian ice sheet drained huge quantities of sediment-laden meltwaters. These meltwaters supplied ice-marginal valleys that formed parallel to the front of the ice sheet. Not without significance was the supply of ice-marginal valleys from extraglacial rivers in the south. Moreover, periglacial conditions during and after sedimentation in ice-marginal valleys, the morphology of valley bedrocks, and erosion of older sediments played important roles in the depositional scenarios, and in the mineralogical composition of the sediments. The mechanisms that controlled the supply and deposition in ice-marginal valleys were analysed on the basis of a Pleistocene ice-marginal valley that was supplied by northern and southern source areas in the immediate vicinity. Investigations were conducted in one of the largest ice-marginal valleys of the Polish-German lowlands, i.e., the Toruń-Eberswalde ice-marginal valley, in sandurs (Drawa and Gwda supplied sediments and waters from the north into this valley, and on extraglacial river terraces (pre-Noteć and pre-Warta rivers, formed simultaneously with the sandurs and ice-marginal valley (Pomeranian phase of Weichselian glaciation supplied sediments and waters from the south into this valley. A much debated question is how similar, or different, depositional processes and sediments were that contributed to the formation of the Toruń-Eberswalde ice-marginal valley, and whether or not it is possible to differentiate mostly rapidly aggraded sandur sediments from ice-marginal valley sediments. Another question addresses the contribution of extraglacial feeding of the Toruń-Eberswalde ice-marginal valley. These matters were addressed by a wide range of analyses: sediment texture and structure, architectural elements of sediments, frequency of sedimentary successions, heavy-mineral analysis (both transparent and opaque heavy minerals, analysis of rounding and frosting of quartz

  5. Gefangen in der Mobilität. Prekäre Zonierungsprozesse an den Rändern Europas. Caught in Mobility. New zones of precarity at the margins of Europe

    Directory of Open Access Journals (Sweden)

    Sabina Hess


    Full Text Available Against the background of the research project TRANSIT MIGRATION (2002–2004 on migration regimes in Turkey, Greece and the Balkan region the article will discuss new processes of zoning and fragmentation of citizenship rights at the fringes of Europe. By analyzing diverse practices of“transit migration” the article can show how the new Europeanised border regime does not totallystop migration. The text rather demonstrates how the deterritorialised and stretched border regimeproduces, in its course of struggling with migrants’ subjectivities and projects, something like “precarioustransit zones”.

  6. "We call ourselves marginalized"

    DEFF Research Database (Denmark)

    Jørgensen, Nanna Jordt


    In recent decades, indigenous knowledge has been added to the environmental education agenda in an attempt to address the marginalization of non-western perspectives. While these efforts are necessary, the debate is often framed in terms of a discourse of victimization that overlooks the agency...... argue that researchers not only need to pay attention to how certain voices are marginalized in Environmental Education research and practice, but also to how learners as agents respond to, use and negotiate the marginalization of their perspectives....

  7. Seismic hazard in low slip rate crustal faults, estimating the characteristic event and the most hazardous zone: study case San Ramón Fault, in southern Andes (United States)

    Estay, Nicolás P.; Yáñez, Gonzalo; Carretier, Sebastien; Lira, Elias; Maringue, José


    Crustal faults located close to cities may induce catastrophic damages. When recurrence times are in the range of 1000-10 000 or higher, actions to mitigate the effects of the associated earthquake are hampered by the lack of a full seismic record, and in many cases, also of geological evidences. In order to characterize the fault behavior and its effects, we propose three different already-developed time-integration methodologies to define the most likely scenarios of rupture, and then to quantify the hazard with an empirical equation of peak ground acceleration (PGA). We consider the following methodologies: (1) stream gradient and (2) sinuosity indexes to estimate fault-related topographic effects, and (3) gravity profiles across the fault to identify the fault scarp in the basement. We chose the San Ramón Fault on which to apply these methodologies. It is a ˜ 30 km N-S trending fault with a low slip rate (0.1-0.5 mm yr-1) and an approximated recurrence of 9000 years. It is located in the foothills of the Andes near the large city of Santiago, the capital of Chile (> 6 000 000 inhabitants). Along the fault trace we define four segments, with a mean length of ˜ 10 km, which probably become active independently. We tested the present-day seismic activity by deploying a local seismological network for 1 year, finding five events that are spatially related to the fault. In addition, fault geometry along the most evident scarp was imaged in terms of its electrical resistivity response by a high resolution TEM (transient electromagnetic) profile. Seismic event distribution and TEM imaging allowed the constraint of the fault dip angle (˜ 65°) and its capacity to break into the surface. Using the empirical equation of Chiou and Youngs (2014) for crustal faults and considering the characteristic seismic event (thrust high-angle fault, ˜ 10 km, Mw = 6.2-6.7), we estimate the acceleration distribution in Santiago and the hazardous zones. City domains that are under

  8. Agricultural land use patterns and their relative gross margins in the ...

    African Journals Online (AJOL)

    Agricultural land use patterns and their relative gross margins in the north-west zone of Nigeria. ... M G Maiangwa, B Okpukpara. Abstract. This study aimed at providing information on the land use practices of farmers and the associated gross margins of different farm production systems in the North-West Zone (NWZ) of ...

  9. Indian Ocean margins

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    The most important biogeochemical transformations and boundary exchanges in the Indian Ocean seem to occur in the northern region, where the processes originating at the land-ocean boundary extend far beyond the continental margins. Exchanges across...

  10. Marginal AMP chain graphs


    Pena, Jose M.


    We present a new family of models that is based on graphs that may have undirected, directed and bidirected edges. We name these new models marginal AMP (MAMP) chain graphs because each of them is Markov equivalent to some AMP chain graph under marginalization of some of its nodes. H