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Sample records for maars tuff-rings tuff-cones

  1. Subsurface structure of a maar-diatreme and associated tuff ring from a high-resolution geophysical survey, Rattlesnake Crater, Arizona

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    Marshall, Anita; Connor, Charles; Kruse, Sarah; Malservisi, Rocco; Richardson, Jacob; Courtland, Leah; Connor, Laura; Wilson, James; Karegar, Makan A.

    2015-10-01

    Geophysical survey techniques including gravity, magnetics, and ground penetrating radar were utilized to study the diatreme and tuff ring at Rattlesnake Crater, a maar in the San Francisco Volcanic Field of northern Arizona. Significant magnetic anomalies (+ 1600 nT) and a positive gravity anomaly (+ 1.4 mGal) are associated with the maar. Joint modeling of magnetic and gravity data indicate that the diatreme that underlies Rattlesnake Crater has volume of 0.8-1 km3, and extends to at least 800 m depth. The modeled diatreme comprises at least two zones of variable density and magnetization, including a low density, highly magnetized unit near the center of the diatreme, interpreted to be a pyroclastic unit emplaced at sufficiently high temperature and containing sufficient juvenile fraction to acquire thermal remanent magnetization. Magnetic anomalies and ground penetrating radar (GPR) imaging demonstrate that the bedded pyroclastic deposits of the tuff ring also carry high magnetization, likely produced by energetic emplacement of hot pyroclastic density currents. GPR profiles on the tuff ring reveal long ( 100 m) wavelength undulations in bedding planes. Elsewhere, comparable bedforms have been interpreted as base surge deposits inflated by air entrainment from eruption column collapse. Interpretation of these geophysical data suggests that Rattlesnake Crater produced highly energetic phreatomagmatic activity that gave way to less explosive activity as the eruption progressed. The positive gravity anomaly associated with the maar crater is interpreted to be caused by coherent bodies within the diatreme and possibly lava ponding on the crater floor. These dense magnetized bodies have excess mass of 2-4 × 1010 kg, and occupy approximately 5% of the diatreme by volume. Magnetic anomalies on the crater floor are elongate NW-SE, suggesting that the eruption may have been triggered by the interaction of ascending magma with water in fractures of this orientation. GPR

  2. Origin of the Joya Honda maar, San Luis Potosí, México

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    Aranda-Gómez, JoséJorge; Luhr, James F.

    1996-11-01

    Joya Honda is a Quaternary maar of unusual type from the Mexican Basin and Range Province. Its ~ 300-m-deep crater is excavated in Cretaceous limestones. The surrounding tephra deposit, which in places is > 100 m thick, begins with a series of weakly indurated pyroclastic-surge and -fall layers that we interpret as dry-surge deposits. These are overlain by the main sequence of strongly indurated, massive tuff breccias that we interpret as wet-surge deposits. Joya Honda formed subaerially from the interaction of groundwater with rapidly ascending intraplate-type basanitic magma carrying peridotitic mantle xenoliths. Local aquifer characteristics controlled the style of eruption and the nature of the deposits. Groundwater in the limestone-hosted aquifer beneath Joya Honda was apparently contained within solution-enhanced fractures. At the onset of the eruption, magma began to interact with a moderate amount of groundwater, producing the dry-surge deposits, which are typical of deposits found at many maars and tuff rings. As the eruption continued, the crater grew and the hydromagmatic blasts fractured the limestones around the explosion foci. A marked increase in the water/magma ratio of the system followed when a large fracture or a portion of the limestone with enhanced secondary permeability was intersected by the expanding crater. Subsequent phreatomagmatic explosions occurred in a system with groundwater flow rates several orders of magnitude larger than in the initial dry-surge stage. At the maar rim these wet eruptions led to the emplacement of massive tuff breccias through a combination of fallout, surges and mudflows. These steeply dipping tuff breccias are similar to deposits found at many tuff cones. Juvenile clasts in the near-vent deposits show marked upward increases in both hydration (palagonitization) and vesicularity. The increased palagonitization with height in the section appears to be a consequence of the overall increased wetness of the eruption

  3. Les anneaux de tufs enfouis : une nouvelle cible pour la recherche de ressources en eau en terrain volcanique. L'exemple des captages de Vourzac (Devès, Massif central français)Hidden tuff rings: a new target for water resource prospecting in volcanic rocks. The case of the well field of Vourzac (Devès, French Massif Central)

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    Boivin, Pierre; Livet, Marc

    2001-06-01

    Several independent and abundant springs are located in the valley of Vourzac. The geological context is a phreatomagmatic tuff-ring overlaid by a Strombolian cone, the two being interbedded in the Devès basaltic plateau. The tuff ring acts as a radial drainpipe system, which collects water at its periphery and drives it to the central part of the ring. The springs are at the intersection of the drainpipe with the talweg of the Vourzac valley. The basaltic plateaus, frequently associated with maars, could often contain such hidden tuff rings. Their detection could be useful to locate and exploit confined aquifers.

  4. Alberca De Guadalupe Maar Crater, Zacapu Basin : A Rare Type of Volcano within the Michoacán-Guanajuato Volcanic Field, México

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    Kshirsagar, P. V.; Siebe, C.; Guilbaud, M. N.; Salinas, S.

    2014-12-01

    Phreato-magmatic vents (esp. maar craters) are rare in the ~40,000 Km2 Plio-Quaternary monogenetic Michoacán-Guanajuato Volcanic Field (MGVF) located in the central part of the Mexican Volcanic Belt. In contrast to >1000 scoria cones, only 2 dozen phreato-magmatic monogenetic vents (e.g. tuff cones, tuff rings, and maars) have been identified. About half of these form a cluster near Valle de Santiago in the Lerma river valley at the northern margin of the MGVF, while the others occur in a rather scattered fashion. Here we discuss the origin of Alberca de Guadalupe maar crater, one of the three phreato-magmatic vents (in addition to El Caracol and Alberca de Los Espinos) that occur within the boundaries of the inter-montane lacustrine Zacapu basin, a tectonic graben bound by an ENE-WSW normal fault system. The maar crater came into existence between 20,000 and 23,000 y BP, forming a 140 m deep hole in the otherwise planar surrounding ground of theearly Pleistocene lava flows of Cerro Pelón.The maar crater has a diameter of ~1 Km and bears a 9 m deep lake. Eruptive products include typical surge deposits that are best exposed around the rim and inner crater walls. They are poorly sorted (Mdø= -1.56 to -3.75, ø= 1.43 to 3.23), rich in accidental lithics (angular andesitic lava and ignimbrite clasts) constituting 51-88% of the deposit with few juveniles (basaltic andesite with phenocrysts of plagioclase, olivine, and pyroxene in a quenched glassy matrix; SiO2=54-58 wt. %). Dry surge units are friable and clast-supported, in contrast the wet surge units are fairly indurated and bear accretionary lapilli. Bedding is frequently distorted by ballistic impact-sag structures. The entire construct is disrupted by an E-W trending regional fault, downthrowing the northern part by ~30 m.The unusual formation of this maar crater in the semi-arid highlands of Zacapu was favored by the local hydrological and topographical conditions. Such conditions still prevail in several

  5. Paleomagnetism in the Determination of the Emplacement Temperature of Cerro Colorado Tuff Cone, El Pinacate Volcanic Field, Sonora, Mexico.

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    Rodriguez Trejo, A.; Alva-Valdivia, L. M.; Vidal Solano, J. R.; Garcia Amador, B.; Gonzalez-Rangel, J. A.

    2014-12-01

    Cerro Colorado Maar is located at the World Heritage Site, biosphere reserve El Pinacate and Gran Desierto del Altar, at the NNW region of Sonora, Mexico (in El Pinacate Volcanic Field). It is a tuff cone, about 1 km diameter, result of several phreatomagmatic episodes during the late Quaternary. We report paleomagnetic and rock magnetic properties from fusiform volcanic bombs obtained from the borders of Cerro Colorado. This study is based in the thermoremanent magnetization TRM normally acquired by volcanic rocks, which can be used to estimate the emplacement temperature range. We performed the experiments on 20 lithic fragments (10 cm to 20 cm approximately), taking 6-8 paleomagnetic cores from each. Rock magnetic experiments (magnetic susceptibility vs. temperature (k-T), hysteresis curves and FORC analysis, shows that the main magnetic mineral carriers of magnetization are titanomagnetite and titanohematite in different levels of intergrowth. The k-T curves suggest in many cases, only one magnetic phase, but also in other cases a second magnetic phase. Thermal demagnetization was used to demagnetize the specimens in detailed short steps and make a well-defined emplacement temperature determination ranges. We found that temperature emplacement determination range for these two magnetic phases is between 350-450 °C, and 550-580 °C, respectively. These results are consistent with those expected in an eruption of Surtsey type, showing a distinct volcanic activity compared to the other craters from El Pinacate volcanic field.

  6. Cerro Xalapaxco: An Unusual Tuff Cone with Multiple Explosion Craters, in Central Mexico (Puebla)

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    Abrams, M. J.; Siebe, C.

    1994-01-01

    The Xalapaxco tuff cone is located on the northeast flank of La Malinche stratovolcano in central Mexico. An unusually large number (10) of explosion craters, concentrated on the central and on the uphill side of the cone, expose alternating beds of stratified surge deposits and massive fall deposits.

  7. Cerro Xalapaxco: An Unusual Tuff Cone with Multiple Explosion Craters, in Central Mexico (Puebla)

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    Abrams, M. J.; Siebe, C.

    1994-01-01

    The Xalapaxco tuff cone is located on the northeast flank of La Malinche stratovolcano in central Mexico. An unusually large number (10) of explosion craters, concentrated on the central and on the uphill side of the cone, expose alternating beds of stratified surge deposits and massive fall deposits.

  8. Scoria Cone and Tuff Ring Stratigraphy Interpreted from Ground Penetrating Radar, Rattlesnake Crater, Arizona

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    Kruse, S. E.; McNiff, C. M.; Marshall, A. M.; Courtland, L. M.; Connor, C.; Charbonnier, S. J.; Abdollahzadeh, M.; Connor, L.; Farrell, A. K.; Harburger, A.; Kiflu, H. G.; Malservisi, R.; Njoroge, M.; Nushart, N.; Richardson, J. A.; Rookey, K.

    2013-12-01

    Numerous recent studies have demonstrated that detailed investigation of scoria cone and maar morphology can reveal rich details the eruptive and erosion histories of these volcanoes. A suite of geophysical surveys were conducted to images Rattlesnake Crater in the San Francisco Volcanic Field, AZ, US. We report here the results of ~3.4 km of ground penetrating radar (GPR) surveys that target the processes of deposition and erosion on the pair of cinder cones that overprint the southeast edge of Rattlesnake crater and on the tuff ring that forms the crater rim. Data were collected with 500, 250, 100, and 50 MHz antennas. The profiles were run in a radial direction down the northeast flanks of the cones (~1 km diameter, ~120 meters height) , and on the inner and outer margins of the oblong maar rim (~20-80 meters height). A maximum depth of penetration of GPR signal of ~15m was achieved high on the flanks of scoria cones. A minimum depth of essentially zero penetration occurred in the central crater. We speculate that maximum penetration occurs near the peaks of the cones and crater rim because ongoing erosion limits new soil formation. Soil formation would tend to increase surface conductivity and hence decrease GPR penetration. Soil is probably better developed within the crater, precluding significant radar penetration there. On the northeast side of the gently flattened rim of the easternmost scoria cone, the GPR profile shows internal layering that dips ~20 degrees northeast relative to the current ground surface. This clearly indicates that the current gently dipping surface is not a stratigraphic horizon, but reflects instead an erosive surface into cone strata that formed close to the angle of repose. Along much of the cone flanks GPR profiles show strata dipping ~4-5 degrees more steeply than the current surface, suggesting erosion has occurred over most of the height of the cone. An abrupt change in strata attitude is observed at the gradual slope

  9. Stratigraphy, sedimentology and eruptive mechanisms in the tuff cone of El Golfo (Lanzarote, Canary Islands)

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    Pedrazzi, Dario; Martí, Joan; Geyer, Adelina

    2013-07-01

    The tuff cone of El Golfo on the western coast of Lanzarote (Canary Islands) is a typical hydrovolcanic edifice. Along with other edifices of the same age, it was constructed along a fracture oriented NEE-SWW that coincides with the main structural trend of recent volcanism in this part of the island. We conducted a detailed stratigraphic study of the succession of deposits present in this tuff cone and here interpret them in light of the depositional processes and eruptive dynamics that we were able to infer. The eruptive sequence is represented by a succession of pyroclastic deposits, most of which were emplaced by flow, plus a number of air-fall deposits and ballistic blocks and bombs. We distinguished five different eruptive/depositional stages on the basis of differences in inferred current flow regimes and fragmentation efficiencies represented by the resulting deposits; the different stages may be related to variations in the explosive energy. Eight lithofacies were identified based on sedimentary discontinuities, grain size, components, variations in primary laminations and bedforms. The volcanic edifice was constructed very rapidly around the vent, and this is inferred to have controlled the amount of water that was able to enter the eruption conduit. The sedimentological characteristics of the deposits and the nature and distribution of palagonitic alteration suggest that most of the pyroclastic succession in El Golfo was deposited in a subaerial environment. This type of hydrovolcanic explosive activity is common in the coastal zones of Lanzarote and the other Canary Islands and is one of the main potential hazards that could threaten the human population of this archipelago. Detailed studies of these hydrovolcanic eruptions such as the one we present here can help volcanologists understand the hazards that this type of eruption can generate and provide essential information for undertaking risk assessment in similar volcanic environments.

  10. Geological and environmental controls on the change of eruptive style (phreatomagmatic to Strombolian-effusive) of Late Pleistocene El Caracol tuff cone and its comparison with adjacent volcanoes around the Zacapu basin (Michoacán, México)

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    Kshirsagar, Pooja; Siebe, Claus; Guilbaud, Marie Noëlle; Salinas, Sergio

    2016-05-01

    The 28,300 year BP (cal 32,300 BP) El Caracol tuff cone complex is one of the few phreatomagmatic volcanoes in the scoria-cone dominated Plio-Quaternary Michoacán-Guanajuato Volcanic Field (MGVF). It displays a shallow circular crater of ~ 1 km in diameter that is filled with several meter-thick lava flows and is located between two NE-SW trending normal faults dipping NW. It lies directly on top of Pliocene lavas of the San Lorenzo shield volcano that forms part of a tectonic horst (topographic high) separating the Zacapu lake basin (1980 m) in the south from the Río Angulo river valley (1760 m) to the north. Detailed study of the tephra sequence indicates that the eruption occurred in two stages: 1) Weak phreatomagmatic, in which about 0.1-0.5 km3 dense rock equivalent (DRE) of magma was issued within ~ 1 to 3 months at the rate of 4-40 m3/s, and 2) purely magmatic (Strombolian-effusive) during which the vent shifted slightly its position toward the NW, forming a small scoria cone (~ 100 m high) on the crater rim of the tuff cone. From this scoria cone lava flows were issued, first into the tuff cone crater occupying its bottom, and subsequently toward the NW, down the outer flank of the tuff cone and into the plain, where they reached a distance of ~ 3.5 km. During this stage ~ 0.6 km3 DRE of magma was produced at the rate of ~ 4 m3/s in a period of ~ 5 months. Although El Caracol displays many features that are characteristic for a phreatomagmatic vent, its morphology, types of deposits, and its complex process of formation makes it strikingly different from the more typical case of the ~ 21,000 year BP (cal 25,300 BP) Alberca de Guadalupe maar volcano, situated not far at the SE margin of the Zacapu basin. The latter was solely phreatomagmatic during the course of its eruption and is formed in its entirety by surge and fallout breccias consisting largely of xenolithic material. In contrast, at El Caracol the hydrogeological environment (namely the low

  11. The palaeogeographic setting and the local environmental impact of the 130 ka Falconiera tuff-cone eruption (Ustica island, Italy)

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    de Vita, Sandro; Foresta Martin, Franco

    2017-04-01

    This research focuses on the effects of the last eruption at Ustica (Suthern Tyrrhenian Sea, Italy), which formed the Falconiera tuff-cone at around 130 ka BP in the north-eastern tip of the island. This eruption was mainly explosive and phreatomagmatic, and emplaced a series of pyroclastic surge beds that formed an asymmetric tuff cone. This is the most easily recognizable volcanic edifice on Ustica, although its north-eastern sector has been partially eroded. A section of the feeding conduit is exposed northward, and is composed of lavas that fed the last stages of the eruption characterized by an intracrateric lava lake and a Strombolian scoria-fallout deposit. The eruption occurred during Upper Pleistocene Marine Isotopic Substage 5.5, a warm period characterized by a high sea-level stand (6±3 m above the present sea level in stable areas) and the diffusion of subtropical flora and fauna across the Mediterranean sea. This eruption slightly modified the morphology of Ustica, but impacted both marine and terrestrial environments, burying beach deposits rich in mollusk shells (i.e. Strombus bubonius, Conus testudinarius, Brachidontes puniceus), colonies of corals (Cladocora caespitosa) and subaerial plants (Chamaerops humilis). These organisms, found in some cases in their life position, along with other lines of evidence, provide information on the palaeogeography of this sector of the island at the time of the eruption, and on the local impact of this event on the environment.

  12. Eruption sequence of the Suwanoharu tuff ring in the Pliocene Oyano formation, western Kyushu, Japan

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    Kosugi, H.; Yokose, H.

    2005-12-01

    Volcanism in the Ariake sea region, west Kyushu, Japan, where is the northern extension of the Okinawa trough, have been active during the last 5 million years, from Pliocene to present Unzen volcano. The region has been subsided with development of the tectonic graben. Pliocene Oyano formation is predominated in shallow marine pyroclastic deposits including some base surge deposits. A series of stratified pyroclastic deposits, which were originated by phreatomagmatic eruption cycles is exposed on a sea cliff and is considered to be a remnant of tuff ring, which is called Suwanoharu tuff ring. Suwanoharu tuff ring is expected to preserve the complete eruption sequence. The sequence is basically alternation of massive white tuff layers and laminated gray coarse to lapilli tuff layers. We can identify seven eruption cycles bounded by the massive white air fall pyroclastic deposits (unit 1- 7). The gray pyroclastic deposits consist of massive dark gray medium tuff, crudely laminated medium to coarse-grained tuff, inversely graded lapilli tuff, cross-bedded lapilli tuff, and lapillistone and are considered to be a base surge deposit. Ascending to the eruption cycles, the thickness of massive white tuff layers is decreasing, but the gray layers are increasing. Representative samples were collected from 42 horizons of the tuff ring sequence and analyzed the bulk rock chemical compositions using XRF and the mineral assemblages using XRD. The bulk rock chemical compositions of the gray layers changes from andesite at the lower horizon to basalt at the upper horizon. On the other hand, massive white tuff layers have almost identical and are andesite. Because the compositions of basal layers are very similar to the silt of the basement rock, the beds in the unit 1 may have been deposited fragmented basement rocks by the first phreatomagmatic eruption. At the upper layers of the first eruption cycle (unit 1), chlorine contents are up to the maximum level (ca. 4%) and the

  13. Diatreme evolution during the phreatomagmatic eruption of the Songaksan tuff ring, Jeju Island, Korea

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    Go, S. Y.; Kim, G. B.; Jeong, J. O.; Sohn, Y. K.

    2017-03-01

    The Songaksan tuff ring, Jeju Island, Korea, which erupted ca. 3.7 ka BP in a coastal setting, provides an unusual opportunity to study the processes of phreatomagmatic eruption and the formation of a diatreme because of the exceptionally well-preserved ejecta beds and well-known subsurface geology. The tuff sequence can be divided into four units (A to D), which have distinctly different accidental componentry (quartz-rich vs. quartz-poor), grain surface features (abraded and ash-coated vs. unabraded and uncoated), and chemical compositions of juvenile particles. The basal tephra bed of unit A, which probably erupted after the removal of the relatively hard shallow-level (120 m deep) accidental grains, suggesting that the early erupted tephra had not yet experienced recycling and pre-eruption mixing in the diatreme. On the other hand, the overlying tephra beds of units A, B, and D contain an abundance of abraded and ash-coated juvenile/accidental grains, suggesting that the tephra comprised significant proportions of "recycled" or "premixed" materials from previous eruptions or subsurface explosions, which participated in the explosion-driven mixing in the diatreme before eventual ejection from the diatreme. Unit C is unusual in that it comprises extremely rare accidental grains and ash-coated juvenile/accidental grains. We interpret that the supply of solid materials, either accidental or juvenile, to the diatreme was greatly reduced because of temporary stabilization of the diatreme and the reduction in magma flux to the diatreme. The diatreme is therefore envisaged to have been filled with a water-saturated slurry, in which particle abrasion and adhesion were inhibited. We also infer that the diatreme fill was temporarily removed by a powerful explosion before eruption of unit C on the basis of the near absence of the tephra grains from earlier eruptions throughout the tephra beds of unit C. The ratio of tachylite to sideromelane grains generally increases up

  14. Structure, stratigraphy, and eruption dynamics of a young tuff ring: Hanauma Bay, O'ahu, Hawai'i

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    Rottas, K. M.; Houghton, B. F.

    2012-09-01

    The Hanauma Bay-Koko Head complex is one of several young volcanic landforms along the Koko fissure, in southeastern O'ahu. The Hanauma Bay region of the complex comprises two nested tuff rings, inner and outer Hanauma Bay, and multiple smaller vents. The internal structure of the inner tuff ring, well exposed due to subsequent breaching by the ocean and wave erosion, indicates that it formed during a minimum of five distinct phases of deposition that produced five mappable units. Significant inward collapses generated major unconformities that separate the units exposed in the inner wall. The planes of failure are cut by narrow steep-walled, locally overhung channels and gullies, suggesting that the collapse events were each followed by short time breaks during which the deposits were eroded by rainfall runoff. Within each pyroclastic unit, there are many local slump scars and unconformities, suggesting that minor instability of the inner wall was a near-constant feature. From bedding sags and surge bed forms, it is apparent that the vent shifted at least twice during tuff ring growth. Ballistic blocks in the youngest unit indicate that the eruption overlapped in time with a separate eruption to the north, most likely to be that of the Kahauloa tuff ring 880 m away.

  15. Complex circular subsidence structures in tephra deposited on large blocks of ice: Varða tuff cone, Öræfajökull, Iceland

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    Smellie, J. L.; Walker, A. J.; McGarvie, D. W.; Burgess, R.

    2016-08-01

    Several broadly circular structures up to 16 m in diameter, into which higher strata have sagged and locally collapsed, are present in a tephra outcrop on southwest Öræfajökull, southern Iceland. The tephra was sourced in a nearby basaltic tuff cone at Varða. The structures have not previously been described in tuff cones, and they probably formed by the melting out of large buried blocks of ice emplaced during a preceding jökulhlaup that may have been triggered by a subglacial eruption within the Öræfajökull ice cap. They are named ice-melt subsidence structures, and they are analogous to kettle holes that are commonly found in proglacial sandurs and some lahars sourced in ice-clad volcanoes. The internal structure is better exposed in the Varða examples because of an absence of fluvial infilling and reworking, and erosion of the outcrop to reveal the deeper geometry. The ice-melt subsidence structures at Varða are a proxy for buried ice. They are the only known evidence for a subglacial eruption and associated jökulhlaup that created the ice blocks. The recognition of such structures elsewhere will be useful in reconstructing more complete regional volcanic histories as well as for identifying ice-proximal settings during palaeoenvironmental investigations.

  16. Felsic maar-diatreme volcanoes: a review

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    Ross, Pierre-Simon; Carrasco Núñez, Gerardo; Hayman, Patrick

    2017-02-01

    Felsic maar-diatreme volcanoes host major ore deposits but have been largely ignored in the volcanology literature, especially for the diatreme portion of the system. Here, we use two Mexican tuff rings as analogs for the maar ejecta ring, new observations from one diatreme, and the economic geology literature on four other mineralized felsic maar-diatremes to produce an integrated picture of this type of volcano. The ejecta rings are up to 50 m+ thick and extend laterally up to ˜1.5 km from the crater edge. In two Mexican examples, the lower part of the ejecta ring is dominated by pyroclastic surge deposits with abundant lithic clasts (up to 80% at Hoya de Estrada). These deposits display low-angle cross-bedding, dune bedforms, undulating beds, channels, bomb sags, and accretionary lapilli and are interpreted as phreatomagmatic. Rhyolitic juvenile clasts at Tepexitl have only 0-25% vesicles in this portion of the ring. The upper parts of the ejecta ring sequences in the Mexican examples have a different character: lithic clasts can be less abundant, the grain size is typically coarser, and the juvenile clasts can be different in character (with some more vesicular fragments). Fragmentation was probably shallower at this stage. The post-eruptive maar crater infill is known at Wau and consists of reworked pyroclastic deposits as well as lacustrine and other sediments. Underneath are bedded upper diatreme deposits, interpreted as pyroclastic surge and fall deposits. The upper diatreme and post-eruptive crater deposits have dips larger than 30° at Wau, with approximately centroclinal attitudes. At still lower structural levels, the diatreme pyroclastic infill is largely unbedded; Montana Tunnels and Kelian are good examples of this. At Cerro de Pasco, the pyroclastic infill seems bedded despite about 500 m of post-eruptive erosion relative to the pre-eruptive surface. The contact between the country rocks and the diatreme is sometimes characterized by country rock

  17. The origin of an unusual tuff ring of perlitic rhyolite pyroclasts: The last explosive phase of the Ramadas Volcanic Centre, Andean Puna, Salta, NW Argentina

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    Tait, M. A.; Cas, R. A. F.; Viramonte, J. G.

    2009-05-01

    A thick sequence of bedded pyroclastic deposits, comprised largely of crystal poor, partially flow-banded perlite fragments defines the remains of a tuff ring around the eastern margin of the Miocene Ramadas Volcanic Centre (RVC), Central Andes, NW Argentina. In numerous quarry exposures, planar bed-forms dominate, but low-angle cross-stratification, lensoidal truncations and lateral pinching and swelling of cm-dm scale bed-forms occur, consistent with pyroclastic surge as the dominant transport and depositional mechanism. Intercalated are mantling, very fine grained, well-sorted, mm-cm scale planar ash layers that represent deposition from pyroclastic fall out and are most likely the products of co-surge ash clouds. Also observed are thick m-scale, laterally continuous, poorly-sorted horizons that are interpreted as pyroclastic flow deposits. Grainsize variations within the > 70 m thick succession range from fine ash to coarse lapilli, with occasional large blocks reaching 20 cm. Clast vesicularities are typically very low. The sequence constitutes a rhyolitic tuff ring around the proximal margins of the RVC. Stratigraphic relationships indicate that the tuff ring was developed following cessation of the major plinian eruption phase of the RVC. A series of pyroclastic density currents and associated ash clouds is inferred to have resulted in the construction of the rhyolitic tuff ring, with deposition focussed on the eastern and southern margins of the central vent. The fine-grained nature of the deposits and low clast vesicularity are consistent with some degree of magma:water interaction during fragmentation. Pervasive perlitic fracturing of clasts found within the tuff deposits also indicates hydration and an extended, post-depositional hydration of the pyroclastic sequence, due to the influence of meteoric water, is likely to have occurred, with deposit permeability, clast specific surface and climate influential in facilitating additional textural

  18. Interpreting subsurface volcanic structures using geologically constrained 3-D gravity inversions: Examples of maar-diatremes, Newer Volcanics Province, southeastern Australia

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    Blaikie, T. N.; Ailleres, L.; Betts, P. G.; Cas, R. A. F.

    2014-04-01

    We present results and a method to geophysically image the subsurface structures of maar volcanoes to better understand eruption mechanisms and risks associated with maar-forming eruptions. High-resolution ground gravity and magnetic data were acquired across several maar volcanoes within the Newer Volcanics Province of southeastern Australia, including the Ecklin maar, Red Rock Volcanic Complex, and Mount Leura Volcanic Complex. The depth and geometry of subsurface volcanic structures were determined by interpretation of gridded geophysical data and constrained 2.5-D forward and 3-D inverse modeling techniques. Bouguer gravity lows identified across the volcanic craters reflect lower density lake sediments and pyroclastic debris infilling the underlying maar-diatremes. These anomalies were reproduced during modeling by shallow coalesced diatremes. Short-wavelength positive gravity and magnetic anomalies identified within the center of the craters suggest complex internal structures. Modeling identified feeder vents, consisting of higher proportions of volcanic debris, intrusive dikes, and ponded magma. Because potential field models are nonunique, sensitivity analyses were undertaken to understand where uncertainty lies in the interpretations, and how the models may vary between the bounds of the constraints. Rather than producing a single "ideal" model, multiple models consistent with available geologic information are created using different inversion techniques. The modeling technique we present focuses on maar volcanoes, but there are wider implications for imaging the subsurface of other volcanic systems such as kimberlite pipes, scoria cones, tuff rings, and calderas.

  19. Volcaniclastic facies architecture of a long-lived, nested silicic tuff ring: the Los Loros volcano, Mendoza, Argentina

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    Németh, Károly; Risso, Corina; Nullo, Francisco

    2010-05-01

    -bedded and having erosional contacts to the underlying pumice fall beds suggest deposition from high particle concentration pyroclastic density currents. This succession is inferred to represent an original pumice ring formation in a braided river network, where external surface and shallow sub-surface water were available to influence the eruption, causing slight phreatomagmatic affinity. This initial volcaniclastic succession is covered by immature, but thick (dm-to-m) pelitic palosoils and/or channel-filling volcanic conglomerates, suggesting a significant time break (tens of thousands of years), erosion and landscape resetting by fluvial networks after the pumice ring was formed. The rejuvenation of the volcanic vent is represented by a thick pyroclastic and lava capping unit. At least three units of trachytic pyroclastic breccias can be separated on the basis of their welding textures and pumice-to-lithic ratios. The gradual transition from stratified trachytic pumiceous beds to welded units indicates that these units are formed from laterally moving pumiceous pyroclastic density currents (e.g. small-volume ignimbrites). The topmost unit of Los Loros is a trachytic lava flow, which is well-preserved in the East. Monomict volcanic conglomerate covers the eastern sector of the lower slopes of Los Loros, suggesting long-lasting alluvial deposition since the volcanism. The eruptive sequence preserved at Los Loros indicates an initial pumice ring formation on an active alluvial plain. The significant time gap between the basal and capping volcanic units suggests a long-lasting inter-eruptive period prior to resumption of volcanic activity, forming small-volume, low aspect ratio trachytic ignimbrites and capping lava flows. Los Loros is a unique volcano in the sense that it "mimics" a tuff ring in its morphology and geometrical parameters; however, its eruptive sequence is more typical to those eruptions associated with large-volume silicic composition volcanoes with

  20. Gunung api maar di Semenanjung Muria

    Directory of Open Access Journals (Sweden)

    Sutikno Bronto

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol2no1.20074Three maars are well identifi ed in the Muria Peninsula, i.e. Bambang Maar, Gunungrowo Maar, and Gembong Maar. The maars were formed by monogenetic volcanic eruptions due to the interaction between heat source (magma, groundwater and calcareous basement rocks. This interaction is able to produce very high pressure of gas and steam causing phreatic explosions, followed by phreatomagmatic- or even magmatic explosions and ended by a lava extrusion. Satellite image analyses have recognized twelve circular features, comprising Bambang Maar, Gunungrowo Maar, and Gembaong Maar. Phisiographically, these maars are characterized by circular depressions which are surrounded by hills that are gently sloping down away from the crater or having a radier pattern morphology. Outcrops and drilling core in the circular areas that are considered as volcanic maars are lava fl ows, pyroclastic breccias, lapillistones, and tuffs, located far away from the eruption centres of Muria and Genuk Volcanoes. One of the circular features, i.e. Jepara Circular Feature, is also supported by negative anomaly (<30 mgal showing a circular pattern. In the future, a maar volcano could possibly erupt depending on the tectonic reactivity in the region.  

  1. Kribbebijters worden niet geboren maar gemaakt

    OpenAIRE

    Visser, E.K.

    2007-01-01

    Paarden en pony’s spelen tegenwoordig nog maar een klein rolletje in de landbouw en bij het transport van mensen en goederen. Maar daarmee zijn ze allerminst uit ons land verdwenen. In tegendeel, bijna een half miljoen exemplaren bieden bijna een miljoen mensen sportief of recreatief plezier. Ze worden door verzorgers vaak verwend en vertroeteld, maar toch blijkt uit onderzoek dat er nog heel wat schort aan hun welbevinden. Met wat goede wil is daar best wat aan te doen

  2. Kanssteekproef, of toch maar de gemakssteekproef?

    NARCIS (Netherlands)

    de Leeuw, Edith

    2014-01-01

    Statistiek is gebaseerd op kanssteekproeven: een aselecte steekproef waarbij ieder element een bekende kans heeft om getrokken te worden. Die kans dient bekend te zijn en mag niet nul zijn, maar hoeft niet voor iedereen gelijk te zijn. Soms worden interessante, maar kleine groepen expres ‘oversample

  3. Kanssteekproef, of toch maar de gemakssteekproef?

    NARCIS (Netherlands)

    de Leeuw, Edith|info:eu-repo/dai/nl/073351385

    2014-01-01

    Statistiek is gebaseerd op kanssteekproeven: een aselecte steekproef waarbij ieder element een bekende kans heeft om getrokken te worden. Die kans dient bekend te zijn en mag niet nul zijn, maar hoeft niet voor iedereen gelijk te zijn. Soms worden interessante, maar kleine groepen expres

  4. Kanssteekproef, of toch maar de gemakssteekproef?

    NARCIS (Netherlands)

    de Leeuw, Edith|info:eu-repo/dai/nl/073351385

    2014-01-01

    Statistiek is gebaseerd op kanssteekproeven: een aselecte steekproef waarbij ieder element een bekende kans heeft om getrokken te worden. Die kans dient bekend te zijn en mag niet nul zijn, maar hoeft niet voor iedereen gelijk te zijn. Soms worden interessante, maar kleine groepen expres ‘oversample

  5. Japanners importeren aardappelkennis maar houden markt gesloten

    NARCIS (Netherlands)

    Haverkort, A.J.

    2009-01-01

    Onlangs is WUR onderzoeker Anton Haverkort door de Janpanse overheid uitgenodigd om de universiteit van het noordelijke eiland Hokkaido in Sapporo te bezoeken. In dit artikel hij een indruk van de aardappel, die een bescheiden, maar een vaste en gewaardeerde plek in Japan heeft veroverd. Het blijft

  6. The expressive 'en maar'-construction

    NARCIS (Netherlands)

    Broekhuis, Hans; Corver, Norbert; Reckmann, Hilke; Cheng, Lisa L.S.; Hijzelendoorn, Maarten; Sybesma, Rint

    2017-01-01

    This article discusses constructions of the type 'En maar zeuren!' (You keep on nagging), which express a negative attitude of the speaker towards the proposition expressed by the construction. We will argue that 'en' (and) should be seen as a regular conjunction conjoining a phonetically empty

  7. Hunting remnants of maar-diatreme-volcanoes

    Science.gov (United States)

    Kroner, Corinna; Kämpf, Horst; Matthes, Heidrun; Jahr, Thomas; Markwart, David; Hermann, Tobias; Mrlina, Jan

    2010-05-01

    In the area of the Rostock-Leipzig-Regensburg fault zone (Germany) several centres of seismic activity are found with seismicity manifesting itself in swarm earthquakes. The occurrence of these earthquakes is globally linked to ascending magma and magmatic fluids. Information is scarce regarding the depth and geometry of the magmatic source, dynamics in the sub-Moho/lower crust region and fluid-tectonic processes in the upper crust in this area. From studies of maar structures located in the seismic active section of the fault zone magma-tectonic phenomena can be reconstructed. For this purpose two relicts of maar volcanoes of different age within a distance of 60 km are investigated by geophysical surveys. Both structures are located in a distance of a few 10 km from recent swarm earthquake centres. The diatreme structure near Ebersbrunn/W-Saxony which is probably of tertiary age is known for several years, the late Quaternary, volcanic palaeo-lake near Mýtina close to the Czech-German border was only recently discovered. Both structures are characterized by distinct gravimetric and magnetic anomalies of about -2 mGal and several 100 nT resp. indicating steeply dipping structures as well as electrical conductivity anomalies. The magnetic total field anomaly of the Ebersbrunn structure has an uncommon rugged appearance. The hypothesis of an origin related to a redistribution of material with high magnetic susceptibility values and saponification of magnetic minerals due to melt water run-off after the last glacial period could not be confirmed. Thus the heterogeneous anomaly character appears to be mainly associated with the degree of weathering of the volcanic material within the diatreme with depth. From 3D gravimetric and magnetic modelling information is gained on geometry and structural composition. Drilling results were used as additional boundary conditions. In both cases modelling reveals an inner zone of significantly reduced density and increased

  8. Official naming of the 1977 maars, south shore, Becharof Lake

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In preparing for a reply to your memo of July 15, 1993, regarding the naming of the Ukinrek Maars following their emplacement in 1977, I once again contacted the...

  9. Origin and age of the Lake Nyos maar, Cameroon

    Science.gov (United States)

    Lockwood, J.P.; Rubin, M.

    1989-01-01

    Lake Nyos occupies a young maar crater in the Precambrian granitic terrane of northwest Cameroon. The lake is partly surrounded by poorly consolidated, ultramafic nodule-bearing pyroclastic surge deposits that were explosively ejected from the Nyos crater at the time of its formation. Radiocarbon dates show that the maar probably formed about 400 years ago. Field evidence suggests that carbon dioxide could have been the principal volatile involved in the formation of the Nyos maar, and that the role of water may have been minor. The formation of the Nyos maar was preceded by a brief period of effusive basaltic volcanism, but the maar itself may have largely formed by cold, 'dry' explosive processes. Carbon dioxide may still be trapped interstitially in a diatreme inferred to underlie Lake Nyos; its gradual release into the waters of Lake Nyos may have set the stage for the tragic gas-release event of August 21, 1986. Only young maar lakes such as Nyos may pose a danger of future lethal gas releases. ?? 1989.

  10. Monogenetic volcanism: personal views and discussion

    Science.gov (United States)

    Németh, K.; Kereszturi, G.

    2015-11-01

    Monogenetic volcanism produces small-volume volcanoes with a wide range of eruptive styles, lithological features and geomorphic architectures. They are classified as spatter cones, scoria (or cinder) cones, tuff rings, maars (maar-diatremes) and tuff cones based on the magma/water ratio, dominant eruption styles and their typical surface morphotypes. The common interplay between internal, such as the physical-chemical characteristics of magma, and external parameters, such as groundwater flow, substrate characteristics or topography, plays an important role in creating small-volume volcanoes with diverse architectures, which can give the impression of complexity and of similarities to large-volume polygenetic volcanoes. In spite of this volcanic facies complexity, we defend the term "monogenetic volcano" and highlight the term's value, especially to express volcano morphotypes. This study defines a monogenetic volcano, a volcanic edifice with a small cumulative volume (typically ≤1 km3) that has been built up by one continuous, or many discontinuous, small eruptions fed from one or multiple magma batches. This definition provides a reasonable explanation of the recently recognized chemical diversities of this type of volcanism.

  11. Interpreting the subsurface architecture of maar volcanoes using geologically constrained 3D gravity inversions

    OpenAIRE

    Blaikie, Teagan; Ailleres, Laurent; Betts, Peter; Cas, Ray

    2016-01-01

    Presentation describing a method for applying forward and inverse gravity and magnetic modelling for understanding the subsurface architecture of maar volcanoes. Results of modelling, implications for understand maar-diatreme eruptions and further applications of modelling results are also presented.

  12. Hogere derving maar omzet en winst ook omhoog

    NARCIS (Netherlands)

    Luitjes, H.; Westra, E.H.

    2004-01-01

    Wageningen UR heeft een ready-to-eatconcept voor mango's in kaart gebracht, waarbij de retailers de derving omhoog zien gaan, maar de omzet en winst ook. "Dit concept is toepasbaar op alle versproducten," aldus Henri Luitjes, hoofd van de afdeling verpakking en logistiek van Wageningen UR agrotechno

  13. Exhibition of photography from the Estonian diaspora / Ellu Maar

    Index Scriptorium Estoniae

    Maar, Ellu, 1982-

    2010-01-01

    Näitus "Photography from the Estonian Diaspora / Väliseesti foto" Kumu Kunstimuuseumis 8.10.-19.11.2010, kuraatorid Eha Komissarov ja Ellu Maar. Näitus tutvustas 1944. a. Eestist lahkunud või juba võõrsil sündinud fotograafide (Eric Soovere, Karl Hintzer, Priit Vesilind, Rein Välme jt.) loomingut ja valikut väliseesti fotoarhiividest

  14. Exhibition of photography from the Estonian diaspora / Ellu Maar

    Index Scriptorium Estoniae

    Maar, Ellu, 1982-

    2010-01-01

    Näitus "Photography from the Estonian Diaspora / Väliseesti foto" Kumu Kunstimuuseumis 8.10.-19.11.2010, kuraatorid Eha Komissarov ja Ellu Maar. Näitus tutvustas 1944. a. Eestist lahkunud või juba võõrsil sündinud fotograafide (Eric Soovere, Karl Hintzer, Priit Vesilind, Rein Välme jt.) loomingut ja valikut väliseesti fotoarhiividest

  15. The origin of a large (> 3 km) maar volcano by coalescence of multiple shallow craters: Lake Purrumbete maar, southeastern Australia

    Science.gov (United States)

    Jordan, S. C.; Cas, R. A. F.; Hayman, P. C.

    2013-03-01

    Lake Purrumbete maar is located in the intraplate, monogenetic Newer Volcanics Province in southeastern Australia. The extremely large crater of 3000 m in diameter formed on an intersection of two fault lines and comprises at least three coalesced vents. The evolution of these vents is controlled by the interaction of the tectonic setting and the properties of both hard and soft rock aquifers. Lithics in the maar deposits originate from country rock formations less than 300 m deep, indicating that the large size of the crater cannot only be the result of the downwards migration of the explosion foci in a single vent. Vertical crater walls and primary inward dipping beds evidence that the original size of the crater has been largely preserved. Detailed mapping of the facies distributions, the direction of transport of base surges and pyroclastic flows, and the distribution of ballistic block fields, form the basis for the reconstruction of the complex eruption history,which is characterised by alternations of the eruption style between relatively dry and wet phreatomagmatic conditions, and migration of the vent location along tectonic structures. Three temporally separated eruption phases are recognised, each starting at the same crater located directly at the intersection of two local fault lines. Activity then moved quickly to different locations. A significant volcanic hiatus between two of the three phases shows that the magmatic system was reactivated. The enlargement of especially the main crater by both lateral and vertical growth led to the interception of the individual craters and the formation of the large circular crater. Lake Purrumbete maar is an excellent example of how complicated the evolution of large, seemingly simple, circular maar volcanoes can be, and raises the question if these systems are actually monogenetic.

  16. High level triggers for explosive mafic volcanism: Albano Maar, Italy

    Science.gov (United States)

    Cross, J. K.; Tomlinson, E. L.; Giordano, G.; Smith, V. C.; De Benedetti, A. A.; Roberge, J.; Manning, C. J.; Wulf, S.; Menzies, M. A.

    2014-03-01

    Colli Albani is a quiescent caldera complex located within the Roman Magmatic Province (RMP), Italy. The recent Via dei Laghi phreatomagmatic eruptions led to the formation of nested maars. Albano Maar is the largest and has erupted seven times between ca 69-33 ka. The highly explosive nature of the Albano Maar eruptions is at odds with the predominant relatively mafic (SiO2 = 48-52 wt.%) foiditic (K2O = 9 wt.%) composition of the magma. The deposits have been previously interpreted as phreatomagmatic, however they contain large amounts (up to 30%vol) of deep seated xenoliths, skarns and all pre-volcanic subsurface units. All of the xenoliths have been excavated from depths of up to 6 km, rather than being limited to the depth at which magma and water interaction is likely to have occurred, suggesting an alternative trigger for eruption. High precision geochemical glass and mineral data of fresh juvenile (magmatic) clasts from the small volume explosive deposits indicate that the magmas have evolved along one of two evolutionary paths towards foidite or phonolite. The foiditic melts record ca. 50% mixing between the most primitive magma and Ca-rich melt, late stage prior to eruption. A major result of our study is finding that the generation of Ca-rich melts via assimilation of limestone, may provide storage for significant amounts of CO2 that can be released during a mixing event with silicate magma. Differences in melt evolution are inferred as having been controlled by variations in storage conditions: residence time and magma volume.

  17. Periodicity of Holocene climatic variations in the Huguangyan Maar Lake

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There exist five primary periods of 2 930, 1 140, 490, 250 and 220 a in the Holocene climatic variations in the Huguangyan Maar Lake, according to the energy-spectrum and filter analyses of high-resolution time sequences (10-15 a) of the sediment dry density. The peak values of the three temperature-decreasing periods with the 2 930 a cycle occur at about 7 300, 4 250 and 1 200 Cal. aBP. There are 7-8 temperature-decreasing periods with the 1 140 a cycle, and the climate fluctuation range is largest in the early Holocene, and reduces gradually in the middle and late Holocene. The millennial-scale climatic change in the Holocene may adjust the global water cycle and the thermohaline circulation intensity through the harmonic tones of the earth's precession cycle, which in turn influences the global climate change.

  18. Maars to calderas: end-members on a spectrum of explosive volcanic depressions

    Directory of Open Access Journals (Sweden)

    Danilo M. Palladino

    2015-07-01

    Full Text Available We discuss maar-diatremes and calderas as end-members on a spectrum of negative volcanic landforms (depressions produced by explosive eruptions (note – we focus on calderas formed during explosive eruptions, recognizing that some caldera types are not related to such activity. The former are dominated by ejection of material during numerous discrete phreatomagmatic explosions, brecciation, and subsidence of diatreme fill, while the latter are dominated by subsidence over a partly evacuated magma chamber during sustained, magmatic volatile-driven discharge. Many examples share characteristics of both, including landforms that are identified as maars but preserve deposits from non-phreatomagmatic explosive activity, and ambiguous structures that appear to be coalesced maars but that also produced sustained explosive eruptions with likely magma reservoir subsidence. A convergence of research directions on issues related to magma-water interaction and shallow reservoir mechanics is an important avenue toward developing a unified picture of the maar-diatreme-caldera spectrum.

  19. Eifel maars: Quantitative shape characterization of juvenile ash particles (Eifel Volcanic Field, Germany)

    Science.gov (United States)

    Rausch, Juanita; Grobéty, Bernard; Vonlanthen, Pierre

    2015-01-01

    The Eifel region in western central Germany is the type locality for maar volcanism, which is classically interpreted to be the result of explosive eruptions due to shallow interaction between magma and external water (i.e. phreatomagmatic eruptions). Sedimentary structures, deposit features and particle morphology found in many maar deposits of the West Eifel Volcanic Field (WEVF), in contrast to deposits in the East Eifel Volcanic Field (EEVF), lack the diagnostic criteria of typical phreatomagmatic deposits. The aim of this study was to determine quantitatively the shape of WEVF and EEVF maar ash particles in order to infer the governing eruption style in Eifel maar volcanoes. The quantitative shape characterization was done by analyzing fractal dimensions of particle contours (125-250 μm sieve fraction) obtained from Scanning electron microscopy (SEM) and SEM micro-computed tomography (SEM micro-CT) images. The fractal analysis (dilation method) and the fractal spectrum technique confirmed that the WEVF and EEVF maar particles have contrasting multifractal shapes. Whereas the low small-scale dimensions of EEVF particles (Eppelsberg Green Unit) coincide with previously published values for phreatomagmatic particles, the WEVF particles (Meerfelder Maar, Pulvermaar and Ulmener Maar) have larger values indicating more complex small-scale features, which are characteristic for magmatic particles. These quantitative results are strengthening the qualitative microscopic observations, that the studied WEVF maar eruptions are rather dominated by magmatic processes. The different eruption styles in the two volcanic fields can be explained by the different geological and hydrological settings found in both regions and the different chemical compositions of the magmas.

  20. Volcanology, history and myths of the Lake Albano maar (Colli Albani volcano, Italy)

    Science.gov (United States)

    De Benedetti, A. A.; Funiciello, R.; Giordano, G.; Diano, G.; Caprilli, E.; Paterne, M.

    2008-10-01

    The polygenetic Albano maar is the most recent centre of the Colli Albani volcano, located just few kilometres to the south-east of Roma. Presently the maar hosts a 167.5 m deep crater lake, the deepest in Europe. The maar is to be considered quiescent, as phreatic activity is documented throughout the Holocene. This paper illustrates the close relationships between the activity of the maar and the history of settlement in the Roman region as recorded in the geology, archaeology, history and legends of the area. Severe fluctuations of the groundwater table and catastrophic overflows of the Lake Albano from the maar rim had occurred prior to and after the early prehistoric settlements dated in the maar area at the Eneolithic times (ca. III millennium B.C.). Repeated lahars occurred along the northwestern slope of the maar filling in the paleodrainage network and forming a vast plain. Paleohydraulic analyses on fluvial and lahar deposits originated from the Holocene phreatic activity of the Albano maar indicate sediment-water flows in excess of hundreds of cubic metres per second. Absolute age determinations of the paleosoil underlying one of the most recent deposits of the lahar succession at 5800 ± 100 yr B.P. ( 14C CAL) are in perfect agreement with the age of the overlying Eneolithic age settlements. The last catastrophic overflow is described in the Roman literature as a consequence of the anger of Poseidon against the Romans in 398 B.C. for their war against the Etruscans. In 394 B.C. the Romans decided to prevent the repetition of such events by the excavation through the maar crater wall of a 1.5 km long drain tunnel, which is still operational, keeping the lake 70 m below the lowest point of the maar rim. This tunnel drain may be regarded as the first prevention device for volcanic hazard in history and shows an unprecedented development of the engineering technology under the pressure of hazard perception. The surprising and still largely unknown results

  1. The recent activity of the lake Albano (Castelgandolfo, Italy) maar.

    Science.gov (United States)

    Funiciello, Renato; Giordano, Guido; de Rita, Donatella; Carapezza, Maria Luisa; Barberi, Franco

    Lake Albano is a complex maar that fed the last phases of Colli Albani volcanic activity. The study of several new stratigraphic sections opened by archeological excavations and civil works has revealed the existence of two previously unknown, primary explosive volcanic deposits, and of several lahar deposits, distributed mainly in the Ciampino plain. Morphological analysis, radiometric dating, the distribution of the early human settlements in the area and the revision of the ancient history and myths of Roma, are coherent in indicating that the activity of lake Albano is much younger than previously believed and extends into Holocene. Until the 4th century B.C. catastrophic exondations have occurred from the lowest rim of the lake, with lahar emplacement on the northern slope. The repetition of these phenomena was prevented by a drain-tunnel dug by the Romans. The overflows were possibly triggered by sudden injections, in the lake bottom, of hot and CO2-rich fluids that are certainly present underneath the volcano. The presence of several gas emission sites, the high CO2 flux in zones corresponding to structural highs of the carbonate basement, the existence of pressurised aquifers also at shallow depth and the reported sudden increase of water temperature and gas release in relation to earthquakes, indicate that a similar hazard persists nowadays.

  2. Structure of the Pliocene Camp dels Ninots maar-diatreme (Catalan Volcanic Zone, NE Spain)

    Science.gov (United States)

    Oms, O.; Bolós, X.; Barde-Cabusson, S.; Martí, J.; Casas, A.; Lovera, R.; Himi, M.; Gómez de Soler, B.; Campeny Vall-Llosera, G.; Pedrazzi, D.; Agustí, J.

    2015-11-01

    Maar volcanoes expose shallower or deeper levels of their internal structure as a function of the degree of erosion. In El Camp dels Ninots maar-diatreme (Catalan Volcanic Zone, Spain), the tephra ring has been largely eroded, and the remaining volcanic deposits infilling the diatreme are hidden under a lacustrine sedimentary infill of the crater. The volcano shows hardly any exposure, so its study needs the application of direct (e.g., boreholes) and indirect (shallow geophysics) subsurface exploration techniques. Additionally, this maar-diatreme was built astride two different substrates (i.e., mixed setting) as a result of its location in a normal fault separating Neogene sediments from Paleozoic granites. In order to characterize the internal structure and post-eruption stratigraphy of the maar-diatreme, we did geological studies (mapping, continuous core logging, and description of the tephra ring outcrops) and near-surface geophysics, including nine transects of electric resistivity tomography and a gravity survey. Results show that the deeper part of the diatreme is excavated into granites and is relatively steep and symmetrical. The uppermost diatreme is asymmetrical because of mechanical contrast between granites and Pliocene sands. The maar crater contained a lake permanently isolated from the surrounding relief and was deep enough to host anoxic bottom waters while its margins had shallower waters. These lake conditions preserved the remarkable Pliocene fossil record found in the lacustrine sediments.

  3. Identification of a Buried Late Cenozoic Maar-Diatreme Structure (North Moravia, Czech Republic

    Directory of Open Access Journals (Sweden)

    Šešulka Vojtěch

    2015-01-01

    Full Text Available The maar-diatreme volcanic structure in the vicinity of the village of Lomnice near the town of Bruntál (North Moravia, Czech Republic has been investigated using a set of geophysical methods including ground magnetometry, gravimetry and electrical resistivity tomography. The structure was detected by an aerial magnetic survey in the second half of the 20th century. Since its discovery only limited information about this buried structure has been available. The coherence of the magnetic anomaly of 190 nT and Bouguer anomaly of -4.7 mGal indicates a volcanic origin of the structure. The funnel-shaped maar-diatreme structure is filled with lacustrine clay and colluvium of Car-boniferous greywacke, which forms the country rock. The surface diameter of the structure is about 600 m, the depth is more than 400 m. The spatial association with other volcanic centers in the surroundings of the town of Bruntál infers the relative dating of the Lomnice maar. The phreatic eruption and maar-diatreme formation could be an indirect conse-quence of effusive activity of the nearby Velký Roudný volcano. The Lomnice structure is the first Plio-Pleistocene maar-diatreme ever described in North Moravia and Silesia.

  4. Discrimination of two kinds of sedimentary laminae in maar lakes of China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Varved lacustrine sediments have been found from high latitude to low latitude, even in tropical area. Paleoenvironmental and paleoclimatic research has increasingly relied on the use of varved sediments to provide high-resolution geochronologies and climatic reconstructions. However, a special depositional environment is necessary for varve formation and preservation. Generally, varves can be found in the sediments of maar lakes because of their special geological and hydrological environment. The preliminary research showed that a few carbonate laminations are developed in the Huguangyan maar lake, south China. They are poorly developed and not annual laminations, and may be related to periodically drought. Diatomaceous laminations are found in the maar lakes in northeast China. Diatomaceous laminations with cyclic nature corresponding with seasonal diatom blooming are the credible natural clock.

  5. Magnetic fabric and implications for pyroclastic flow and lahar emplacement, Albano maar, Italy

    Science.gov (United States)

    Porreca, M.; Mattei, M.; Giordano, G.; de Rita, D.; Funiciello, R.

    2003-05-01

    The Albano polygenetic maar is the youngest eruptive center of the quiescent Colli Albani volcano, located near the city of Rome. The most recent activity of the Albano maar extends from ˜23 ka into the Holocene and produced the small volume, basic, phreatomagmatic Peperino Albano (PA) ignimbrite, and, more recently, phreatomagmatic surge and lahar deposits related to the overspill of the Albano maar lake. We have performed an anisotropy of magnetic susceptibility (AMS) study, in order to define the relationships between the magnetic fabric and the flow mechanisms of the PA and of the phreatomagmatic deposits and lahars. AMS results indicate different transport and/or depositional systems for the veneer and valley pond facies in the PA ignimbrite and for the lahar deposits. AMS also demonstrates that flow directions are mainly controlled by the paleotopography. The paleotopographic control has been interpreted in terms of talweg sedimentation even at proximal locations where deposition occurs from dilute pyroclastic flows. Furthermore, AMS results clearly evidence a southward provenance for Holocene post-PA ignimbrite units, cropping out in the Ciampino plain, and confirm their origin from Albano maar lake overspill. We demonstrate that AMS is a reliable marker to determine paleoflow directions also in small volume phreatomagmatic ignimbrites and in syneruptive lahar deposits and can be successfully used to define their depositional systems.

  6. Kijken naar porno : Subcorticale hersenactiviteit weerspiegelt negatieve maar niet positieve impliciete seksuele associaties

    NARCIS (Netherlands)

    Bosman, Renske; Borg, Charmaine; Jong, de Peter J.; Georgiadis, Janniko

    Samenvatting Achtergrond Aan de ene kant kunnen mensen visuele seksuele stimulatie (VSS) ervaren als plezierig, maar aan de andere kant kunnen mensen VSS ook ervaren als iets “viezigs” en negatief. Dit onderzoek richt zich op de vraag hoe het brein bij vrouwen reageert op VSS en hoe de

  7. New thermoluminescence age estimates for the Nyos maar eruption (Cameroon Volcanic Line).

    Science.gov (United States)

    Schmidt, Christoph; Tchouankoue, Jean Pierre; Nkouamen Nemzoue, Peguy Noel; Ayaba, Félicité; Nformidah-Ndah, Siggy Signe; Nformi Chifu, Emmanuel

    2017-01-01

    Nyos maar is located in the Cameroon Volcanic Line and generates a multitude of primary and secondary hazards to the local population. For risk assessment and hazard mitigation, the age of the Nyos maar eruption provides some vital information. Since previous dating efforts using a range of techniques resulted in vastly varying eruption ages, we applied thermoluminescence (TL) methods to obtain independent and direct chronological constraints for the time of maar formation. Target minerals were granitic quartz clasts contained in pyroclastic surge deposits. Thermoluminescence plateau results prove that heat and/or pressure during the phreatomagmatic eruption was sufficient to reset the inherited luminescence signal of granitic bedrock quartz. Parallel application of three TL measurement protocols to one of the two samples gave consistent equivalent doses for the quartz ultra-violet emission. Despite the robustness of our dose estimates, the assessment of the dose rate was accompanied by methodological challenges, such as estimation of the original size distribution of quartz grains in the pyroclastic deposits. Considering results from additional laboratory analyses to constrain these uncertainties, we calculate an average maximum TL age of 12.3 ± 1.5 ka for the Nyos maar eruption. Based on these new data, a more solid risk assessment can be envisaged.

  8. The formation and evolution of Hule and Río Cuarto maars, Costa Rica

    Science.gov (United States)

    Alvarado, Guillermo E.; Soto, Gerardo J.; Salani, Flavia M.; Ruiz, Pablo; de Mendoza, Luis Hurtado

    2011-04-01

    The Hule and Río Cuarto maars are respectively located 11 and 18 km northward of the active crater of Poás volcano, on the Caribbean side of the Central Volcanic Range of Costa Rica. They lie on the northern part of Poás volcano massif, along a N-S trending, ~ 27 km-long volcanic fracture crossing the Poás volcano. The volcanic products from Hule maar (2.3 km × 1.8 km, area ~ 3.5 km 2) are mainly pyroclastic surges (poorly vesiculated andesites with very small plagioclases), silica-rich andesitic pumice flows, air-fall deposits, ballistic blocks, and reworked deposits that overlie the regional Pleistocene volcanic basement. They were produced during three main explosive phases. Two overlapping pyroclastic cones have developed within the Hule maar, and at least three lava fields are related to them (high-Al basalt to basaltic andesite). Another maar, Pata de Gallo (400 m across), is located less than 1 km off the SE rim of Hule. Río Cuarto is a nearly circular maar (700-850 m across) with a surface area of 0.33 km 2. Río Cuarto products include surges, ballistics and air-fall tephra, produced during three main explosive phases. These deposits show a narrow fan oriented westward, according to westerly wind direction. They indicate a westerly-directed surge (first 2 km), followed by air-fall deposits (up to 5 km away). Radiocarbon dating has shown that Hule was formed ~ 6.2 ka ago and Pata de Gallo probably formed ~ 2.8 ka ago, while the intra-maar products could have ages of ~ 1.7 ka or ~ 0.7 ka, indicating that Hule is a polygenetic maar. There are no radiocarbon ages yet for dating the formation of Río Cuarto maar, but archaeological data suggest that it erupted between 3-4 ka ago. The volume of pyroclastic deposits associated to Hule maar is estimated to be 0.51-0.53 km 3, from which ~ 20% is juvenile material, therefore 0.07-0.08 km 3 of new dense rock equivalent (DRE) magma, after subtracting 20-30% of porosity. The tephra from Río Cuarto is estimated

  9. OSL dating of a Pleistocene maar: Birket Ram, the Golan heights

    Science.gov (United States)

    Shaanan, U.; Porat, N.; Navon, O.; Weinberger, R.; Calvert, A.; Weinstein, Y.

    2011-01-01

    Direct dating of maars and their phreatomagmatic deposits is difficult due to the dominance of lithic (host rock) fragments and glassy particles of the juvenile magma. In this paper we demonstrate that optically stimulated luminescence (OSL) dating can be successfully used for age determination of phreatomagmatic deposits. We studied the tuff deposit of Birket Ram, a basanitic maar located at the northern edge of the Golan heights on the western Arabian plate. The maar is underlain by a thick section of Pleistocene basalts, and currently hosts a small lake. It is filled by approximately 90m of lacustrine sediments with radiocarbon ages extrapolated to 108ka at the base. OSL was applied to quartz grains extracted from tuffs and paleosols in order to set the time frame of the phreatomagmatism at the site. A maximum age constraint of 179??13ka was determined for a paleosol that underlies the maar ejecta. Quartz grains from two layers in the tuff section yielded a direct age of 129??6ka for the phreatomagmatic eruption. A younger age of 104??7ka, which was determined for a tuff layer underlying a basaltic flow, was attributed to thermal resetting during the lava emplacement. This was confirmed by an 40Ar/39Ar age of 101??3ka determined on the overlying basalt. The internal consistency of the OSL ages and the agreement with the 40Ar/39Ar age determination as well as with previous estimates demonstrates the potential of OSL for maar dating. ?? 2010 Elsevier B.V.

  10. Alteration of hydrovolcanic basaltic ash - Observations with visible and near-infrared spectrometry

    Science.gov (United States)

    Farrand, William H.; Singer, Robert B.

    1992-01-01

    Altered basaltic tephras from tuff rings and tuff cones across the Basin and Range were examined using visible and NIR (Vis/IR) reflectance spectrometry and a variety of other techniques. It was found that Vis/IR spectrometry is sensitive to subtle changes in the hydration and oxidation state of these tephras. In the tuffs examined, ferrous and ferric iron minerals produce one composite absorption feature rather than two resolvable bands. Different styles of alteration were noted between thinly bedded tuff ring deposits emplaced by high energy, largely dry, pyroclastic surge and massively bedded tuff cone deposits emplaced by wetter, lower energy pyroclastic flow. The former class of tephras become hydrated and only moderately oxidized with some limited development of dioctehedral smectite clay minerals and minimal palagomitization. The latter class of tephras are highly palagonitized which implies a high degree of hydration and oxidation. In the most of highly altered tephras, all the Fe(2+) that is initially in the volcanic glass is converted to Fe(3+) within nanophase and bulk ferric oxide phases in the palagonite. There is also more extensive development in tuff cone beds of zeolite and phyllosilicate minerals. The differences in reflectance spectra of altered basaltic tephras can be traced to initial differences in the water/magma ratio extant at the volcanic vent.

  11. High-resolution records of Holocene from the Shuangchi Maar Lake in Hainan Island

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The results of sedimentary characteristics, grain-size, clay mineral, C/N and pollen analysis reveal the evolution history of the Shuangchi Maar Lake of Hainan Island as well as the short-term climate variations in tropical areas. It is testified that the Maar sediment system was sensitive in recording the rapid climate changes in the Holocene. These multidisciplinary results demonstrate that the thermal maximum in the Holocene climate lasted from 7200 to 2700 aBP, with several abrupt ephemeral vibrations occurring between 7250-6120 aBP and at around 4460, 3850 and 2700 aBP. In the late Holocene, particularly at ~2700 aBP, a distinct environmental change indicating an important climate transition in the tropical eastern Asia was recorded, probably responding to the enhancement of ENSO phenomena in the Pacific Ocean. In addition, the high-resolution algae record clearly indicates periodical climate fluctuations at 500 a cyclicity during the last 2500 years.

  12. Geophysical surveys of the Joya Honda maar (México) and surroundings; volcanic implications

    Science.gov (United States)

    López Loera, Héctor; Aranda-Gómez, José Jorge; Arzate, Jorge A.; Molina-Garza, Roberto Stanley

    2008-03-01

    Joya Honda (JH) is a Quaternary maar excavated in Mesozoic limestone. It is located in central Mexico and belongs to the Ventura volcanic field (VVF), which is composed by cinder cones and maars made of intraplate-type mafic alkalic rocks. Volcanoes in the region form ˜ N20W lineaments, roughly parallel to a regional set of normal faults, but there is no obvious relation between these faults and vent distribution in the exposed geology around the maar. The volcanic rock volume is small in the VVF, and most volcanoes and their products are scattered in a region where outcrops are dominated by limestone. The near-vent tephra associated to the JH maar lies north of the crater. This relation suggests that the crater was formed by directed hydromagmatic explosions and may indicate an inclined volcanic conduit near the surface. The tephra stratigraphy suggests that the initial explosions were relatively dry and the amount of water increased during the maar forming eruption. Therefore, the existing model of the maar-diatreme formation may not be applicable to Joya Honda as it requires the formation of a cone of depression in the aquifer and deepening of the focii of the explosions as the crater and underlying diatreme grew. Thus, it is unlikely that there is a diatreme below Joya Honda. Aeromagnetic data shows a boundary between two regional magnetic domains near the elongated volcanic cluster of the VVF. The boundary is straight, with a distinct kink, from NE- to NW-trend, near JH. The limit between the domains is interpreted as fault contacts between mid-Tertiary volcanic rocks and marine Mesozoic sedimentary rocks. Hence, magma ascent in the area may have been facilitated by fractures near the surface. Magnetic and gravimetric ground surveys show that the anomalies associated with the maar are not centered in the crater, which could be consistent with an inclined volcanic conduit. A magnetic profile measured on exposed limestone across the volcanic lineament failed to

  13. Economic and ecologic importance of the non - metalic deposits in basalt maars of Southern Slovakia

    Directory of Open Access Journals (Sweden)

    Vass Dionýz

    1998-03-01

    Full Text Available By investigation of the basalt maars infill in Luèenská kotlina Depression the diatomite and alginite deposits have been found. Both maars belong to Podreèany basalt formation, Pontian (Late Miocene in age. By technological investigation it was proved the diatomite can be used in the building trade as raw materil for light tiles convenient especially for the construction of the saddle roof with attic appatments. The alginite can be used in the agriculture and horticulture, as a fertiliser becouse of humus, nutritive end same trace elements, a desodorant in livestoc feedlots, a water and nutritive elements trap to distribute them for the growing plants. The alginite can be used as well as in pharmacy and in different industrial branches. Both deposits are of high significance for the ecology and the nature protection.

  14. The Maars of the Tuxtla Volcanic Field: the Example of 'laguna Pizatal'

    Science.gov (United States)

    Espindola, J.; Zamora-Camacho, A.; Hernandez-Cardona, A.; Alvarez del Castillo, E.; Godinez, M.

    2013-12-01

    Los Tuxtlas Volcanic Field (TVF), also known as Los Tuxtlas massif, is a structure of volcanic rocks rising conspicuously in the south-central part of the coastal plains of eastern Mexico. The TVF seems related to the upper cretaceous magmatism of the NW part of the Gulf's margin (e.g. San Carlos and Sierra de Tamaulipas alkaline complexes) rather than to the nearby Mexican Volcanic Belt. The volcanism in this field began in late Miocene and has continued in historical times, The TVF is composed of 4 large volcanoes (San Martin Tuxtla, San Martin Pajapan, Santa Marta, Cerro El Vigia), at least 365 volcanic cones and 43 maars. In this poster we present the distribution of the maars, their size and depths. These maars span from a few hundred km to almost 1 km in average diameter, and a few meters to several tens of meters in depth; most of them filled with lakes. As an example on the nature of these structures we present our results of the ongoing study of 'Laguna Pizatal or Pisatal' (18° 33'N, 95° 16.4'W, 428 masl) located some 3 km from the village of Reforma, on the western side of San Martin Tuxtla volcano. Laguna Pisatal is a maar some 500 meters in radius and a depth about 40 meters from the surrounding ground level. It is covered by a lake 200 m2 in extent fed by a spring discharging on its western side. We examined a succession of 15 layers on the margins of the maar, these layers are blast deposits of different sizes interbedded by surge deposits. Most of the contacts between layers are irregular; which suggests scouring during deposition of the upper beds. This in turn suggests that the layers were deposited in a rapid series of explosions, which mixed juvenile material with fragments of the preexisting bedrock. We were unable to find the extent of these deposits since the surrounding areas are nowadays sugar cane plantations and the lake has overspilled in several occassions.

  15. The Randeck Maar: Facies development and habitat differentiation of a Miocene lacustrine system

    Science.gov (United States)

    Rasser, Michael W.; Kern, Andrea K.

    2015-04-01

    The Randeck Maar in S Germany is a well-known fossil lagerstätte (Early/Middle Miocene, MN5) with exceptionally preserved fossils. Although it is a locally restricted succession of lake sediments with a diameter of only 1200 m and less than 60 m of preserved sediments, it appears to comprise a complex structure with a high scientific potential on a global scale, because the lake sediments and their fossils can provide evidence for the impact of the Mid-Miocene Climatic Optimum (MMCO) on the environment and its organisms as well as the ecological interactions between animals and/or plants during that interval. No other European locality provides such a rich insight into an ecosystem that existed during the MMCO. Excavations of Staatliches Museum für Naturkunde Stuttgart provided new insights into the facies types of this maar lake. They showed that a high variety of facies types existed beside the traditional separation into a basal tuffitic development, followed by calcareous and bituminous ('dysodil') laminates, and terminal massive freshwater limestones. Palaeoenvironmental reconstructions are based on the mentioned excavations and re-evaluations of collection material. They show that the Randeck Maar was a typical maar lake with a rich flora and fauna. Based on all plant remains, the IPR vegetational analysis points towards subhumid sclerophyllous forests, suggesting seasonal drought. 380 taxa in all are known thus far, which are dominated by plants (168) and insects (79). The taxonomic re-evaluation combined with palaeoecological considerations allows for the reconstruction of a palaeoenvironmental model. In brief, three main sections can be differentiated for the habitats of the Randeck Maar lake system: (1) Deep- and open-water lake habitats with local and short-termed mass occurrences of insect larvae, amphibians, and/or gastropods, while fish are particularly scarce. The interpretation of the water chemistry is problematic because palaeoenvironmental

  16. Base surge deposits, eruption history, and depositional processes of a wet phreatomagmatic volcano in Central Anatolia (Cora Maar)

    Science.gov (United States)

    Gençalioğlu-Kuşcu, Gonca; Atilla, Cüneyt; Cas, Ray A. F.; Kuşcu, İlkay

    2007-01-01

    Cora Maar is a Quaternary volcano located to the 20 km northwest of Mount Erciyes, the largest of the 19 polygenetic volcanic complexes of the Cappadocian Volcanic Province in central Anatolia. Cora Maar is a typical example of a maar-diatreme volcano with a nearly circular crater with a mean diameter of c.1.2 km, and a well-bedded base surge-dominated maar rim tephra sequence up to 40 m in thickness. Having a diameter/depth ratio ( D/ d) of 12, Cora is a relatively "mature" maar compared to recent maar craters in the world. Cora crater is excavated within the andesitic lava flows of Quaternary age. The tephra sequence is not indurated, and consists of juvenile clasts up to 70 cm, non-juvenile clasts up to 130 cm, accretionary lapilli up to 1.2 cm in diameter, and ash to lapilli-sized tephra. Base surge layers display well-developed antidune structures indicating the direction of the transport. Both progressive and regressive dune structures are present within the tephra sequence. Wavelength values increase with increasing wave height, and with large wavelength and height values. Cora tephra display similarities to Taal and Laacher See base surge deposits. Impact sags and small channel structures are also common. Lateral and vertical facies changes are observed for the dune bedded and planar bedsets. According to granulometric analyses, Cora Maar tephra samples display a bimodal distribution with a wide range of Md φ values, characteristic for the surge deposits. Very poorly sorted, bimodal ash deposits generally vary from coarse tail to fine tail grading depending on the grain size distribution while very poorly sorted lapilli and block-rich deposits display a positive skewness due to fine tail grading.

  17. Anthropogenic influences on Pb/Al and lead isotope signature in annually layered Holocene Maar lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Schettler, G.; Romer, R.L. [GeoForschungsZentrum Potsdam, Telegrafenberg, D-14473 Potsdam (Germany)

    1998-08-01

    Annually laminated sediments from two Maar lakes in the West Eifel volcanic field (Germany) show anomalously high Pb within sections deposited during the first centuries A.D. exceeding the local geological background 8.5-fold in Lake Meerfelder Maar (MFM) and 4-fold in Lake Schalkenmehrener Maar (SMM). These Pb anomalies are associated with a distinct shift in the Pb isotope signature to less radiogenic compositions. The excess Pb causing the anomaly has the same isotopic composition as galena deposits 60 km to the NW of the Maar lakes. It is suggested that this component was transported airborne into the Maar lakes and originates from regional Roman Pb refinement and cupellation of argentiferous Pb. Varve chronostratigraphy of correlated cores indicates that significant Roman Pb input lasted for about 230 a. SMM does not get fluviatile input. Its sedimentary record is more sensitive to variations in airborne input than that of MFM, which had an inflow. SMM sediment sections deposited during periods of low soil erosion (early Holocene, Dark Ages) with comparably high Pb/Al values also show little radiogenic Pb. This is caused by airborne minerogenic matter from a geochemically and isotopically distinct remote source that becomes apparent only in sedimentation periods of very restricted local allochthonous input. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. 米国New Mexico州の火山地域の地形とその分類

    OpenAIRE

    守屋, 以智雄

    1990-01-01

    Geomorphology and evolution of the volcanic fields in New Mexico have been studied. Thirteen volcanic fields being active in the late Tertiary-Quaternary are classified into 4 - A, B, C, and D types. A-type volcanic fields are simple lava fields, composed of basaltic lava flows, scoria cones, tuff rings, tuff cones, and small shields. B-type volcanic fields are lava fields on which small to medium-scale andesitic stratovolcanoes and dacitic to rhyolitic lava domes stand. C-type volcanic field...

  19. Physical experiments of land subsidence within a maar crater: insights for porosity variations and fracture localization

    Science.gov (United States)

    Cerca, M.; Rocha, L.; Carreón-Freyre, D.; Aranda, J.

    2015-11-01

    We present the results of a series of physical models aiming to reproduce rapid subsidence (at least 25 m in 30 years) observed in the sediments of a maar crater caused by extraction of groundwater in the interconnected adjacent aquifer. The model considered plausible variations in the geometry of the crater basement and the measured rate of groundwater extraction (1 m per year in the time interval from 2005 to 2011) in 15 wells located around the structure. The experiments were built within a rigid plastic bowl in which the sediments and rocks of the maar sequence were modeled using different materials: (a) plasticine for the rigid country rock, (b) gravel for the fractured country rock forming the diatreme fill and, (c) water saturated hollow glass microbeads for the lacustrine sedimentary fill of the crater. Water table was maintained initially at the surface of the sediments and then was allowed to flow through a hole made at the base of the rigid bowl. Water extraction provoked a sequence of gentle deformation, fracturing, and faulting of the surface in all the experiments. Vertical as well as lateral displacements were observed in the surface of the experiments. We discuss the results of 2 representative models. The model results reproduced the main geometry of the ring faults affecting the crater sediments and helps to explain the diversity of structures observed in relation with the diatreme geometry. The surface of the models was monitored continuously with an optical interferometric technique called structured light projection. Images collected at nearly constant time intervals were analyzed using the ZEBRA software and the obtained interferometric pairs permitted to analyze the full field subsidence in the model (submilimetric vertical displacements). The experiments were conducted at a continuous flow rate extraction and show a also a linear subsidence rate. Comparison among the results of the physical models and the fault system associated to

  20. Eckfeld Maar: Window into an Eocene Terrestrial Habitat in Central Europe

    Institute of Scientific and Technical Information of China (English)

    Herbert LUTZ; Martin KOZIOL; Uwe KAULFUSS; Torsten WAPPLER; Werner L(O)HNERTZ; Volker WILDE; Dieter F.MERTZ; Jens MINGRAM; Jens L.FRANZEN; Herbert FRANKENH(A)USER

    2010-01-01

    To mark the occasion of the 175th anniversary of the Rheinische Naturforschende Gesellschaft in 2009 and of the centennial of the Mainz Natural History Museum in 2010,we present a short account of our present knowledge of the Eckfeld Maar after 20 years of continuous research.This paper does not attempt to include all of the detailed results on the geology of the Eckfeld site or its biota.To date,nearly 250 papers and books have been published since the start of our project.An up-to-date list of these publications can be found at www.eckfeldermaar.de.

  1. Magma ascent, fragmentation and depositional characteristics of "dry" maar volcanoes: Similarities with vent-facies kimberlite deposits

    Science.gov (United States)

    Berghuijs, Jaap F.; Mattsson, Hannes B.

    2013-02-01

    Several maar craters within the Lake Natron-Engaruka monogenetic volcanic field (LNE-MVF) of northern Tanzania show compelling evidence for magmatic fragmentation and dry deposition. This is in contradiction of the common belief that most maars are formed through the explosive interaction between ascending magma and ground- or surface water. We here present a detailed study on the eruptive and depositional characteristics of the Loolmurwak and Eledoi maar volcanoes, two of the largest craters in the LNE-MVF, focusing on high-resolution stratigraphy, sedimentology, grain size distribution, pyroclast textures and morphologies, bulk geochemistry and mineral chemistry. At both maars, ejected material has been emplaced by a combination of pyroclastic surges and fallout. Indicators of phreatomagmatic fragmentation and wet deposition, such as impact sags, accretionary lapilli, vesiculated tuffs and plastering against obstacles, are absent in the deposits. Juvenile material predominantly occurs as fluidal-shaped vesicular melt droplets and contains no glass shards produced by the breakage of bubble walls. The Eledoi deposits comprise a large amount of inversely graded beds and lenses, which result from grain flow in a dry depositional environment. Preferential deposition of fine material toward the northern side of its crater can be related to effective wind winnowing in a dry eruption plume. This large variety of observations testifies to the dominance of magmatic fragmentation as well as dry deposition at the Loolmurwak and Eledoi maars, which is in line with what has been found for other structures in the LNE-MVF but contrasts with current ideas on maar formation. We infer that a volatile-rich, olivine melilitic magma was formed by small amounts of partial melting at upper mantle depths. With minimum average ascent rates of 5.3 m s- 1 for Loolmurwak and 26.2 m s- 1 for Eledoi, this magma rapidly moved toward the surface and exsolved a substantial amount of volatiles

  2. Influence of the substrate on maar-diatreme volcanoes — An example of a mixed setting from the Pali Aike volcanic field, Argentina

    Science.gov (United States)

    Ross, Pierre-Simon; Delpit, Séverine; Haller, Miguel J.; Németh, Károly; Corbella, Hugo

    2011-04-01

    The morphologic parameters, pyroclastic deposits and evolution of maar-diatreme volcanoes are affected by the type of environment in which they are emplaced. End-member cases are a hard substrate (rocks) and a soft substrate (unconsolidated volcaniclastic or sedimentary deposits). In this paper, we present an example of a volcanic complex emplaced in a mixed hard-soft setting from the Pali Aike volcanic field (PAVF) near the Argentina-Chile border. The Plio-Pleistocene PAVF is an alkaline, mafic, back-arc monogenetic field which contains over 100 phreatomagmatic volcanoes. The studied volcanic complex contains two large coalescent maars overlain by scoria and spatter. The 1.4 × 1.3 km East Maar has better exposures than the shallower, 1.9 km-wide West Maar and seems to have been less modified by post-eruptive processes. The tephra rim of the East Maar was studied in detail and we infer it was produced mostly by base surges from phreatomagmatic eruption columns, with rare instances of intercalated scoria fall layers. Based on regional information, the general pre-maar stratigraphy is dominated by sedimentary and volcaniclastic rocks of the Magallanes Basin, including a thick poorly consolidated upper unit dating from the Miocene. These are overlain by Plio-Pleistocene fluvio-glacial deposits and PAVF lavas, some of which are exposed in the East Maar just below the phreatomagmatic deposits. All of these units are represented as lithic clasts in the tephra rim of the East Maar, the most abundant being the clasts from the earlier basaltic lavas and rock fragments derived from the glacial deposits. There is no specific evidence for a deep diatreme under the East Maar, and in this particular case, the mixed environment seems to have produced a maar-diatreme volcano typical of a soft substrate.

  3. Een onbekende vrouw heeft een visioen van een geliefde die zij niet noemt...Maar dat is Hadewijch!

    NARCIS (Netherlands)

    Vandermeersch, Patrick

    2000-01-01

    P. Vandermeersch, Een onbekende vrouw heeft een visioen van een geliefde die zij niet noemt... Maar dat is Hadewijch! In: D. Pätzold, P. Vandermeersch & H. Wilcox, `What's in a Name?' Three Essays on Naming and Individual Identity, Groningen, Onderzoeksschool Rudolf Agicola Instituut, 2000, 9-18.

  4. Multidisciplinary characterisation of sedimentary processes in a recent maar lake (Lake Pavin, French Massif Central and implication for natural hazards

    Directory of Open Access Journals (Sweden)

    E. Chapron

    2010-09-01

    Full Text Available Sedimentation processes occurring in the most recent maar lake of the French Massif Central (Lake Pavin are documented for the first time based on high resolution seismic reflection and multibeam bathymetric surveys and by piston coring and radiocarbon dating on a sediment depocentre developed on a narrow sub aquatic plateau. This new data set confirms the mid Holocene age of maar lake Pavin formation at 6970±60 yrs cal BP and highlights a wide range of gravity reworking phenomena affecting the basin. In particular, a slump deposit dated between AD 580–640 remoulded both mid-Holocene lacustrine sediments, terrestrial plant debris and some volcanic material from the northern crater inner walls. Between AD 1200 and AD 1300, a large slide scar mapped at 50 m depth also affected the southern edge of the sub aquatic plateau, suggesting that these gas-rich biogenic sediments (laminated diatomite are poorly stable. Although several triggering mechanisms can be proposed for these prehistoric sub-aquatic mass wasting deposits in Lake Pavin, we argue that such large remobilisation of gas-rich sediments may affect the gas stability in deep waters of meromictic maar lakes. This study highlights the need to further document mass wasting processes in maar lakes and their impacts on the generation of waves, favouring the development of dangerous (and potentially deadly limnic eruptions.

  5. Origin and evolution of the Laguna Potrok Aike maar (Patagonia, Argentina)

    Science.gov (United States)

    Gebhardt, A. C.; de Batist, M.; Niessen, F.; Anselmetti, F. S.; Ariztegui, D.; Ohlendorf, C.; Zolitschka, B.

    2009-04-01

    Laguna Potrok Aike, a maar lake in southern-most Patagonia, is located at about 110 m a.s.l. in the Pliocene to late Quaternary Pali Aike Volcanic Field (Santa Cruz, southern Patagonia, Argentina) at about 52°S and 70°W, some 20 km north of the Strait of Magellan and approximately 90 km west of the city of Rio Gallegos. The lake is almost circular and bowl-shaped with a 100 m deep, flat plain in its central part and an approximate diameter of 3.5 km. Steep slopes separate the central plain from the lake shoulder at about 35 m water depth. At present, strong winds permanently mix the entire water column. The closed lake basin contains a sub saline water body and has only episodic inflows with the most important episodic tributary situated on the western shore. Discharge is restricted to major snowmelt events. Laguna Potrok Aike is presently located at the boundary between the Southern Hemispheric Westerlies and the Antarctic Polar Front. The sedimentary regime is thus influenced by climatic and hydrologic conditions related to the Antarctic Circumpolar Current, the Southern Hemispheric Westerlies and sporadic outbreaks of Antarctic polar air masses. Previous studies demonstrated that closed lakes in southern South America are sensitive to variations in the evaporation/precipitation ratio and have experienced drastic lake level changes in the past causing for example the desiccation of the 75 m deep Lago Cardiel during the Late Glacial. Multiproxy environmental reconstruction of the last 16 ka documents that Laguna Potrok Aike is highly sensitive to climate change. Based on an Ar/Ar age determination, the phreatomagmatic tephra that is assumed to relate to the Potrok Aike maar eruption was formed around 770 ka. Thus Laguna Potrok Aike sediments contain almost 0.8 million years of climate history spanning several past glacial-interglacial cycles making it a unique archive for non-tropical and non-polar regions of the Southern Hemisphere. In particular, variations of

  6. Assessment of local seismic response of the Stracciacappa maar (Central Italy)

    Science.gov (United States)

    Moscatelli, Massimiliano; Simionato, Maurizio; Gaudiosi, Iolanda; Sottili, Gianluca; Pagliaroli, Alessandro; Sirianni, Pietro; Pileggi, Domenico; Avalle, Alessandra; Giallini, Silvia; Razzano, Roberto; Mancini, Marco; Vignaroli, Gianluca; Piscitelli, Sabatino; Bellanova, Jessica; Calamita, Giuseppe; Perrone, Angela; Lanzo, Giuseppe

    2016-04-01

    In this work, we face the definition of a subsoil model aimed at the local seismic response assessment of the Stracciacappa maar (Sabatini Volcanic District, central Italy) (e.g., De Rita and Zanetti, 1986; Marra et al., 2014). The pyroclastic succession of Stracciacappa records two main hydromagmatic eruptive phases ended about 0.09 Ma ago (e.g., Sottili et al., 2010). The preserved crater, with a diameter of about 1500 meters and a crater floor of about 30-40 m, hosted a lake until it was drained in AD 1834. In the framework of the cooperation between CNR IGAG and Italian Department of Civil Protection (DPC) of the Presidency of Council of Ministers (DPC funds 2014), a multidisciplinary approach including detailed stratigraphic and geophysical study has been carried out in the Stracciacappa maar and surrounding areas. New geological map and cross sections illustrate the complex geometric relationships between the thick pyroclastic surge succession, showing diffuse sandwave structures, and even meter-sized lava ballistic. A composite interdigitation between lacustrine and epiclastic debris sediments fills the crater floor. A continuous coring borehole was drilled inside the crater, 45 meters deep from the wellhead, with sampling of undisturbed samples. In addition, four MASW and one SCPTU test were carried out, in order to define the velocity profile of the s-waves within the lacustrine deposits. This Vs profile was then extended at higher depths by using the results of four 2D seismic passive arrays. Moreover, in order to define the resonance frequency of sedimentary covers via the HVSR technique, twenty-eight measurements were carried out with digital sensor Tromino® and seven measurements were performed with a Lennartz® Le-3D/5s sensor with Lennartz Marslite® digitizer. Finally, three electrical resistivity tomography tests, with a total length of about 3500 meters, were carried out with the purpose of constraining the subsoil model. Regarding the non linear

  7. ELSA flood stack for MIS 2-3 from dry maar lakestructure Auel (Eifel/Germany)

    Science.gov (United States)

    Brunck, Heiko; Sirocko, Frank

    2015-04-01

    Lacustrine sediments are very sensitive to natural and anthropogenically enviromental changes. Thus, lake sediments are excellent climate archives and can be used for reconstructions of past precipitation and flood events. However, until now, there is no continous flood record for the entire last 60 000 years for Central Europe. The present study reconstructs paleo floods from event layers in the sediment, of dry maar lakestructure Auel (Eifel). This silted up basin has an inflow by a local stream. Accordingly the sedimentation rate is directly linked to runoff activity. The bioturbation was low so that event layers become visible, but varves are not preserved. The maar site is near to the town of Gerolstein in the Eifel; the core AU2 was drilled in the ELSA (Eifel Laminated Sediment archive) project and is 123m long. AU2 has the highest sedimentation rate of all ELSA cores, due to abundant fluvial input. The Eifel area is well suited to approximate Central European weather, because modern water level gauge data from Eifel rivers correlate with respective data from the Rhine (Wernli and Pfahl, 2009). Due to the high inflow into the maar, Auel has the highest number of botanical macro remains of all ELSA cores. These specific conditions explain why only in AU2 all 21 Greenland interstadials can be observed in the abundance of wood remains and the organic carbon concentration. In a final stratigraphic step the time series of Corg was tuned to the Greenland ice core chronology to link the central European landscape evolution directly to the Greenland climate curve (Svensson et al., 2008). Combined sedimentological, paleobotanical and geochemical data received from AU2 builds the foundation of the 14C based chronology. The synchronisation of the record with other cores is controlled by tephra time markers and pollen. Both are used to align the main cores of the ELSA project and construct an integrated age model for the last 220 000 years [b2k] (Förster and Sirocko

  8. Numerical dating of the Eckfeld maar fossil site, Eifel, Germany: a calibration mark for the Eocene time scale.

    Science.gov (United States)

    Mertz, D F; Swisher, C C; Franzen, J L; Neuffer, F O; Lutz, H

    2000-06-01

    Sediments of the Eckfeld maar (Eifel, Germany) bear a well-preserved Eocene fauna and flora. Biostratigraphically, Eckfeld corresponds to the Middle Eocene mammal reference level MP (Mammals Paleogene) 13 of the ELMA (European Land Mammal Age) Geiseltalian. In the maar crater, basalt fragments were drilled, representing explosion crater eruption products. By 40Ar/39Ar dating of the basalt, for the first time a direct numerical calibration mark for an Eocene European mammal locality has been established. The Eckfeld basalt inverse isochron date of 44.3 +/- 0.4 Ma suggests an age for the Geiseltalian/Robiacian boundary at 44 Ma and, together with the 1995 time scale of Berggren et al., a time span ranging from 49 to 44 Ma for the Geiseltalian and from 44 to 37 Ma for the Robiacian, respectively. Additional 40Ar/39Ar dating on a genetically related basalt occurrence close to the maar confirms a period of volcanism of ca. 0.6 m.y. in the Eckfeld area, matching the oldest Eocene volcanic activity of the Hocheifel volcanic field.

  9. The Albano multiple-maar center (Rome, Italy): an active volcanic area since 70 ka

    Science.gov (United States)

    Freda, C.; Gaeta, M.; Karner, D. B.; Marra, F.; Renne, P. R.; Scarlato, P.; Taddeucci, J.

    2003-04-01

    The Albano multiple-maar center hosted the most recent activity of the Alban Hills Volcanic District. The determination of its petrochemical characteristics and its geochronology is therefore of great importance in order to evaluate the status of this volcanic area and to assess the possible volcanic hazard for Rome. Despite the detailed 40Ar/39Ar geochronologic history of the products of its activity, relatively poor information on the stratigraphy and the petrology of this volcanic center exists. In order to develop a detailed chronostratigraphy, petrology, and a more thorough knowledge of the eruptive mechanisms that characterized the recent activity of the Albano center, a joint research project is being conducted by scientists from the Istituto Nazionale di Geofisica e Vulcanologia, the University of California at Berkeley, and the Berkeley Geochronology Center. Here we have studied the most complete stratigraphic section located within the northern crater rim of Albano, where most of the products are exposed. We have investigated proximal and distal outcrops, in order to correlate them to the units identified in the northern crater rim section. We will present our recently acquired geochronologic and petrochemical data, which indicates magma chamber recharge associated with this <70 ka volcanism.

  10. A Flood Layer Reconstruction from the Laminated Sediments of Eifel Maar Structures (Germany) during the Last 60 000 Years

    Science.gov (United States)

    Brunck, H.; Sirocko, F.

    2015-12-01

    Lake sediments are excellent climate archives and can be used for reconstructions of past precipitation and flood events. However, until now, there is no continous flood record for the entire last 60 000 years for Central Europe. This study reconstructs the history of the main flood events in central Europe from event layers in sediment cores from Holocene Eifel maar lakes and Pleistocene dry maar structures. The cores were drilled in the Eifel region of western Germany. All maars have an inflow by a local stream and the largest flood events and associated suspension injections are nicely visible in the sediment. The specific sedimentation conditions explain the unique possibility to detect all 18 Greenland Interstadials in the total carbon concentration of the analysed maars. The allocation of the core material to all Greenland Interstadials and Stadials enables the exact climatic interpretation of the flood frequency. The stratigraphical concept leads to a classification of Landscape Evolution Zones in the Eifel region, which reconstruct the vegetation and the climate change. This classification is used to discuss the flood event succession concerning environmental changes. To study the past flood events in detail, 10 cm long thin sections were sedimentological and geochemical analysed to distinguish flood layers from turbidites and slumps.Turbidites have a continuous grain size gradation; the grain size profile of flood events is in contrast characterized by several grain size maxima over the entire layer thickness. A flood event over several days shows numerous peaks of intense discharge, which lead to a discontinuous grain size gradient. As a consequence, 233 flood layers over 7.5 mm thickness were detected. The main flood stages are from: 0 - 4000, 11 500 - 17 500, 23 000 - 24 000, 29 000 - 35 000 and 44 000 - 44 500 b2k. Our time-series from the Eifel represents the first highly-resolved chronology for flood events from 60 000 years until present times and

  11. The ELSA - Flood - Stack: A reconstruction from the laminated sediments of Eifel Maar structures during the last 60 000 years

    Science.gov (United States)

    Brunck, Heiko; Sirocko, Frank; Albert, Johannes

    2016-04-01

    Lake sediments are excellent climate archives and can be used for reconstructions of past precipitation and flood events. However, until now, there is no continous flood record for the entire last 60 000 years for Central Europe. This study reconstructs the history of the main flood events in central Europe from event layers in sediment cores from Holocene Eifel maar lakes and Pleistocene dry maar structures. The cores were drilled in the Eifel region of western Germany. All maars have an inflow by a local stream and the largest flood events and associated suspension injections are nicely visible in the sediment. The specific sedimentation conditions explain the unique possibility to detect all 18 Greenland Interstadials in the total carbon concentration of the analysed maars. The allocation of the core material to all Greenland Interstadials and Stadials enables the exact climatic interpretation of the flood frequency. The stratigraphical concept leads to a classification of Landscape Evolution Zones in the Eifel region, which reconstruct the vegetation and the climate change (Sirocko et al., 2015). This classification is used to discuss the flood event succession concerning environmental changes. To study the past flood events in detail, 10 cm long thin sections were sedimentological and geochemical analysed to distinguish flood layers from turbidites and slumps. Turbidites have a continuous grain size gradation; the grains size profile of flood events is in contrast characterized by several grain size maxima over the entire layer thickness. A flood event over several days shows numerous peaks of intense discharge, which lead to a discontinuous grain size gradient. As a consequence, 233 flood layers over 7.5 mm thickness were detected. The main flood stages are from: 0 - 4000, 11 500 - 17 500, 23 000 - 24 000, 29 000 - 35 000 and 44 000 - 44 500 b2k (Brunck et al., 2015). Our time-series from the Eifel represents the first highly-resolved chronology for flood

  12. The role of phreatomagmatism in a Plio-Pleistocene high-density scoria cone field: Llancanelo Volcanic Field (Mendoza), Argentina

    Science.gov (United States)

    Risso, Corina; Németh, Károly; Combina, Ana María; Nullo, Francisco; Drosina, Marina

    2008-01-01

    The Plio-Pleistocene Llancanelo Volcanic Field, together with the nearby Payun Matru Field, comprises at least 800 scoria cones and voluminous lava fields that cover an extensive area behind the Andean volcanic arc. Beside the scoria cones in the Llancanelo Field, at least six volcanoes show evidence for explosive eruptions involving magma-water interaction. These are unusual in the context of the semi-arid climate of the eastern Andean ranges. The volcanic structures consist of phreatomagmatic-derived tuff rings and tuff cones of olivine basalt composition. Malacara and Jarilloso tuff cones were produced by fallout of a range of dry to wet tephra. The Malacara cone shows more evidence for a predominance of wet-emplaced units, with a steep slump-slope characterized by many soft-sediment deformation structures, such as: undulating bedding planes, truncated beds and water escape features. The Piedras Blancas and Carapacho tuff rings resulted from explosive eruptions with deeper explosion loci. These cones are hence dominated by lapilli tuff and tuff units, emplaced mainly by wet and/or dry pyroclastic surges. Carapacho is the only centre that appears to have started with phreatomagmatic eruptions, with lowermost tephra being rich in non-volcanic country rocks. The presence of deformed beds with impact sags, slumping textures, asymmetrical ripples, dunes, cross- and planar lamination, syn-volcanic faulting and accretionary lapilli beds indicate an eruption scenario dominated by excessive water in the transportational and depositional regime. This subordinate phreatomagmatism in the Llancanelo Volcanic Field suggests presence of ground and/or shallow surface water during some of the eruptions. Each of the tuff rings and cones are underlain by thick, fractured multiple older lava units. These broken basalts are inferred to be the horizons where rising magma interacted with groundwater. The strong palagonitization at each of the phreatomagmatic cones formed hard beds

  13. Multiproxy Paleoenvironmental Records Spanning the INTIMATE Timescale from Auckland Maar Lakes, New Zealand

    Science.gov (United States)

    Augustinus, Paul; D'Costa, Donna; Stephens, Tom; Atkin, Dan; Shane, Phil; Cochran, Ursula; Snowball, Ian; Nilsson, Andreas; Street-Perrott, Alayne; Davies, Sarah

    2010-05-01

    High-resolution Late Quaternary paleoclimate archives are preserved in the lake sediment records contained in several maar craters from the Auckland region in northern New Zealand. Tephrochronology, AMS 14C and Ar/Ar -based chronostratigraphies were developed with several lakes containing laminated sediment records spanning much of the last glacial cycle. A multi-proxy approach was taken to construct a reliable record of local and regional paleoenvironments including: pollen and diatom paleoecology, environmental magnetism, grain size, XRF geochemistry, TOC, TN, TS, organic matter δ13C, δ15N and δD, as well as δ18O in biogenic silica. Pollen and diatom analysis of records spanning the last ca 60 ka show marked vegetation changes that reflect orbital forcing, although diatoms suggest significant hydrological changes that are not reflected in the pollen. Reduction of forest with expansion of grass and shrublands at the start of the LGM (29 ka BP), is accompanied by cool, dry and windy conditions, although the situation is complex with multiple brief warmer phases punctuating the LGM. Post-glacial warming commenced ca 17.9 ka BP and is reflected in several proxies, although the pollen record does not display the marked changes displayed in many of the other proxies during the LGIT and Holocene. Some of the inferred environmental changes are similar to the nature and timing of short-duration events during the last glacial cycle from the North Atlantic region, although others appear to reflect a southern polar forcing. The multi-proxy approach used has produced one of the most complete, well-dated and high-resolution paleoenvironmental records spanning the INTIMATE timescale from the mid-latitude Southern Hemisphere with implications for the nature, timing and forcings of climate change in the Southwest Pacific region.

  14. Late-stage magmatic processes at Albano Maar, Colli Albani, Italy: insights from FTIR analysis of leucites

    Science.gov (United States)

    Cross, J. K.; Roberge, J.; Smith, V.; Giordano, G.; Tomlinson, E.; Menzies, M. A.

    2011-12-01

    The recently erupted Albano Maar, one of the Via dei Laghi phreatomagmatic eruptions of Colli Albani, Italy have eruptive deposits that are K-foiditic (9wt% K2O) and silica under-saturated (48-52wt% SiO2). These compositions suggest the melts are low viscosity [1, 2], but they fuelled very explosive eruptions, namely the widespread large Peperino ignimbrite (phreato-Plinian) deposits. Therefore a question asked by researchers is how could these melts explode and would they, if they had not interacted with groundwater? Experimental work has shown that the melt chemistries at Colli Albani require a volatile saturated system [3]. Consequently the CO2 and H2O content of the melts are critical to understanding the petrogenetic processes at Albano Maar. Since the juvenile tephra clasts exhibit extensive late stage micro-crystallization (mainly leucite), analysis of glass is difficult and not representative as the majority of the volatile components may have exsolved from the melt. Melt inclusions are also commonly recrystallized and often leaky so here we unravel the complex volatile histories of the melts using the abundant leucite crystals, which have been shown to contain magmatic water in recent studies [4]. FTIR analysis of leucite phenocrysts and microcrysts within juvenile tephra clasts (syn-eruptive) of all the erupted units at Albano Maar provide an interesting insight into volatile variations and record a late stage CO2 fluxing event, which would have contributed to the explosive nature of the eruptions. This study has also allowed for an increased understanding of the nominally anhydrous minerals (NAMs) that crucially record volatile speciation and fluxing in high level magmatic systems. [1] Freda et al., 2006, Bul Vol, 68, pp567-591 [2] Cross et al., 2011 IUGG abs [3] Freda et al., 2008, Lithos, pp397-415 [4] Ventura et al., 2008, Am Min, 93, pp1538-1544

  15. Origin and evolution of the Laguna Potrok Aike maar (Southern Patagonia, Argentina) as revealed by seismic data

    Science.gov (United States)

    Gebhardt, C.; de Batist, M. A.; Niessen, F.; Anselmetti, F.; Ariztegui, D.; Haberzettl, T.; Ohlendorf, C.; Zolitschka, B.

    2009-12-01

    Seismic reflection and refraction data provide insights into the sedimentary infill and the underlying volcanic structure of Laguna Potrok Aike, a maar lake situated in the Pali Aike Volcanic Field, Southern Patagonia. The lake has a diameter of ~3.5 km, a maximum water depth of ~100 m and a presumed age of ~770 ka. Its sedimentary regime is influenced by climatic and hydrologic conditions related to the Antarctic Circumpolar Current, the Southern Hemispheric Westerlies and sporadic outbreaks of Antarctic polar air masses. Multiproxy environmental reconstructions of the last 16 ka document that this terminal lake is highly sensitive to climate change. Laguna Potrok Aike has recently become a major focus of the International Continental Scientific Drilling Program and was drilled down to 100 m below lake floor in late 2008 within the PASADO project. The sediments are likely to contain a continental record spanning the last ca. 80 kyrs unique in the South American realm. Seismic reflection data show relatively undisturbed, stratified lacustrine sediments at least in the upper ~100 m of the sedimentary infill but are obscured possibly by gas and/or coarser material in larger areas. A model calculated from seismic refraction data reveals a funnel-shaped structure embedded in the sandstone rocks of the surrounding Santa Cruz Formation. This funnel structure is filled by lacustrine sediments of up to 370 m in thickness. These can be separated into two distinct subunits with low acoustic velocities of 1500-1800 m s-1 in the upper subunit pointing at unconsolidated lacustrine muds, and enhanced velocities of 2000-2350 m s-1 in the lower subunit. Below these lacustrine sediments, a unit of probably volcanoclastic origin is observed (>2400 m s-1). This sedimentary succession is well comparable to other well-studied sequences (e.g. Messel and Baruth maars, Germany), confirming phreatomagmatic maar explosions as the origin of Laguna Potrok Aike.

  16. The Albano Maar Lake (colli Albani Volcano, Italy): History of A Pre-roman Age Killer Lake.

    Science.gov (United States)

    Funiciello, R.; Giordano, G.; de Rita, D.

    The evaluation of volcanic hazard in the Roman hinterland related to the quiescent Colli Albani volcano has recently been the subject of renewed attention and several interpretations by many authors. However, very little was known up-to-date of the re- cent history of the volcano making such interpretations rather speculative. The most recent activity from Colli Albani volcano originated from the Albano polygenetic maar lake, which erupted several phreatomagmatic units, the most recent of which, the Peperino Albano ignimbrite, has been dated at around 25 ka. An area of several square kilometres centred around the Albano lake is presently interested by shallow and frequent seismic activity and gaseous emission as well as hydrothermal activity and is therefore considered the most prone to geologic hazards. This paper presents new stratigraphic and geomorphologic data as well as age determinations that allow to reconstruct the most recent activity of the Colli Albani volcano, and particularly of the Albano maar lake, since last known eruption to Holocene. This study allows for the first time to identify a potential hazard related to the Albano maar lake withdrawal interpreted to be related to endogenous causes, and namely CO2 emission. The main results of the study are: a) the Peperino Albano is not, as generally believed, the last phreatomagmatic eruption from the Colli Albani volcano; a previously unrecognised phreatomagmatic surge deposit has been identified overlying the paleosol at the top of the Peperino Albano and related lahar deposits; b) two lahar deposits separated by paleosols top the stratigraphic succession and are dispersed only to the NW, that corresponds to the lowest point of the maar rim, indicating that catastrophic hydro- logic events occurred from the Albano lake in recent times; rapid and substantial lake level variations and lake withdrawal are reported by Roman historians and recorded by the stratigraphy of the Albano lake lacustrine sediments

  17. New Constraints on Maar Geometry and Sedimentary Fill of Laguna Potrok Aike, Southern Patagonia

    Science.gov (United States)

    Gebhardt, C. A.; Niessen, F.; Anselmetti, F.; Ariztegui, D.; de Batist, M.; Haberzettl, T.; Ohlendorf, C.; Zolitschka, B.

    2007-12-01

    Laguna Potrok Aike is located in Southern Patagonia, Argentina, at 52°S and 70°W. The maar lake has a diameter of 3.5 km and is almost circular and bowl-shaped with a deep, flat plain (100 m water depth) in its central part. Steep flanks separate the lake shoulders at 15 to 35 m water depth from the central plain. The lake is situated in the Pali Aike Volcanic Field at the present boundary between the Southern Hemispheric Westerlies and the Antarctic Polar Front. Its lake level is highly susceptible to changes in the Antarctic Circumpolar Current that controls the regional precipitation patterns. Its sedimentary infill possibly contains a long and continuous record of several glacial and interglacial cycles, which is unique in the southern South American realm. Two major stratigraphic units (I and II) were distinguished in the seismic sections. Unit I consists of the lacustrine infill and was further subdivided into Sub-units I-a and I-b on the lake shoulders and I-ab, I-c, and I-d in the central basin. Sub-units I-a and I-b on the lake shoulders are separated by a major unconformity and contain several paleoshoreline structures formed during a step-wise transgression after a lake level lowstand of approx. 35 m below the present lake level. In the central basin, Sub-units I-a and I-b are merged into Sub-unit I-ab, not being separated by any unconformity. Pelagic sedimentation dominates in the northern and central parts, whereas mass movement deposits were found in the southern, western and eastern parts close to the steep diatreme flanks. The boundary between I-ab and I-c is non-erosive with I-ab forming downlaps onto I-c from the eastern and western parts of the lake, pointing at a significantly lower lake level during its accumulation. Sub-unit I-d shows similar characteristics as I-ab. The bedrock (Unit II) that forms the steep diatreme flanks consists of the well-layered sandstones found in the lake surroundings.

  18. Changes in mid to late Holocene monsoon strength in eastern Mexico inferred from high-resolution maar lake sediments

    Science.gov (United States)

    Bhattacharya, T.; Byrne, R.; Wogau, K.; Bohnel, H.

    2013-12-01

    Understanding the Holocene variation in central Mexico's summer precipitation can help identify the processes responsible for climatic change and clarify the role of climate in Mesoamerican cultural change. We present proxy results from Aljojuca, a maar lake in the Oriental-Serdan Basin in Mexico's Trans-Mexican Volcanic Belt. The 12 m sediment core from Aljojuca features a laminated, high-resolution proxy archive. A chronology established via radiocarbon dating shows a basal date of 6,200 cal. years B.P. We use fluctuations in pollen, elemental geochemistry, and the stable isotope ratios of authigenic carbonates to reconstruct the timing and duration of mid to late Holocene droughts in central Mexico. We compare these results with geochemical analyses of maar wall rocks and palynological analyses of modern moss polsters to strengthen our interpretations of proxy results. We interpret periods of aridity as periods of reduced summer precipitation and therefore decreased summer monsoon strength. Our results reveal evidence of a gradual decrease in monsoon strength from the mid to late Holocene. We also identify a multi-century dry period between 1,150 and 800 cal yr. BP, coinciding with the abandonment of the nearby fortified city of Cantona. Spatiotemporal analysis of this and other paleoclimatic records reveals region-wide evidence of this ';Terminal Classic' drought, although its timing is spatially heterogeneous. Our results represent one of the only high-resolution mid-Holocene records from the eastern Trans-Mexican Volcanic Belt.

  19. Study of the varve record from Erlongwan maar lake,NE China, over the last 13 ka BP

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In a sediment sequence from Erlongwan maar lake that spans the last 13 ka BP, two main varve types can be recognized: biogenic varves (from the present to ~11.2 ka BP, 0-632 cm) and clastic varves (from ~11.2 to ~12.7 ka BP, 632-700 cm). Based on the dominant types of algae contained in the sediment, the biogenic varves can be classified into dinocyst-biogenic varves (0-63 cm) and mixed (dinocyst and diatom)-biogenic varves (214-632 cm). In this paper, the formation process and components of the varve are described, the possible reason for the types of varve changing throughout the record is discussed and a high-resolution varve chronology is established spanning the last 13 ka BP.Although further varve counting and error assessment are needed, the results presented here represent a solid foundation for studying the palaeoclimate record of Erlongwan maar lake.

  20. Compositional and Textural Analysis of Maar-Diatreme Volcanic Deposits at Hopi Buttes Volcanic Field (AZ) Using GigaPan Panoramic and Thermal Infrared Imagery

    Science.gov (United States)

    Lee, R.; Graettinger, A. H.; Weinell, M.; Hughes, C. G.

    2016-12-01

    Basaltic maar-diatreme volcanoes are produced when rising magma interacts with groundwater and produces a maar crater at the ground surface. This crater is underlain by a diatreme, a downward-tapering conical structure filled with a mixture of fragments of intruded magma, fractured host rock, and clasts recycled through repeated discrete subsurface explosions. The debris of the diatreme records the mixing processes caused by subsurface explosions and is the source for ejected material that forms maar tephra rings. Determining the variable depths and lateral locations of these explosions and how energy is dissipated in the subsurface is critical to understanding how maar-diatreme eruptions progress. The Hopi Buttes Volcanic Field (HBVF) in the Navajo Nation, Arizona, USA, contains several diatremes and incised tephra rings with heterolithic clasts 10 mm - 10 m in size, and are well-exposed near-vertical to vertical outcrops. Our ability to measure the length scales and distribution of textures produced by subsurface explosions in these diatremes is limited by the physical accessibility of the exposures, due to both the verticality of the outcrops and the cultural sensitivity of the site. Quantifying the number and locations of explosions is dependent on our ability to investigate the full diatreme outcrop, and not just what can be accessed through traditional field observations. We present a novel field and computer-based technique for both quantitatively and qualitatively characterizing the composition and texture of maar-diatreme deposits in vertical outcrops. This technique uses a combination of field-collected multispectral thermal infrared (TIR) image data and visible wavelength GigaPan imagery to characterize the compositional and textural variations over a whole outcrop. To increase the spatial and spectral resolution of the TIR data, a super-resolution technique will be applied. The technique provides a simple and efficient method to augment the study of the

  1. Omgang met lepra in ‘de West’ in de negentiende eeuw. Tegendraadse maar betekenisvolle geluiden vanuit Suriname

    Directory of Open Access Journals (Sweden)

    Henk Menke

    2014-05-01

    Full Text Available Aan de hand van de ontwikkeling en invloed van een zogenaamd ‘West-Indisch lepra-conta- gionisme’ zullen wij in dit artikel laten zien dat de vertaalslag van medisch-wetenschappelijke noties en concepten naar beleid en voorschriften (mede bepaald wordt door andere dan medisch inhoudelijke factoren. Volgens de Amerikaanse historicus Baldwin bestaat er een correlatie tussen profylactische strategieën, politiek en ideologie. Maar hij laat ook zien dat het niet om de tegenstelling tussen een conservatieve en/of autoritaire neiging tot interventie en een liberale neiging tot laissez-faire gaat. Sterker nog: onder de vlag van het hygiënisme pro- pageerden liberalen juist publieke gezondheidsmaatregelen waartegen conservatieven vaak in het geweer kwamen. Het draait bij de ontwikkeling en keuze voor interventies veel meer om verschillende soorten van afwegingen tussen individuele en collectieve belangen, ver- antwoordelijkheden en rechten in diverse landen. Het is de vraag of het West-Indische leprabestrijdingsysteem gefaciliteerd werd door de politieke en ideologische bestuursstructuur van de slavensamenleving aldaar. De koloniën in de West hadden een autoritaire bestuursstructuur, die zich weinig gelegen liet aan de rechten van met name de niet-blanke bewoners. Maar was dit een voldoende voorwaarde voor het gevolgde traject van een profy- lactische strategie? En bestaat er een relatie tussen de aanscherping van het bestrijdingsbeleid en een verharding van de medische opvattingen over lepra als besmettelijke ziekte in West- Indië? In dit artikel zullen we de historische ontwikkeling van de wetgeving betreffende de bestrijding van besmettelijke ziekten, in het bijzonder lepra, koppelen aan de ontwikkeling van een medisch-wetenschappelijk West-Indisch lepracontagionisme. We zullen laten zien hoe bepaalde kennis en beleid betreffende lepra gedijden binnen een specifieke lokale context – Suriname met zijn quarantainebeleid – zonder invloed te

  2. Estudio vulcanológico y qeoquímico del maar de la Caldera del Rey. Tenerife (Canarias

    Directory of Open Access Journals (Sweden)

    Paradas Herrero, A.

    1984-12-01

    Full Text Available In this study a cartographic, morphological, geochemical and petrographic study is made of the ''Caldera del Rey". The "Caldera del Rey" is a volcanic structure formed by two overlapping maars, The second one (maar that was formed is of greaten dimensions and destroyed part of the first one, Both maars erupted throught a possible fracture N 35 E, which is one of the directions with regional importance in the Archipelago. The eruption, which was very explosive, has been thought to be due in part to the great importance of the gaseous phase of the salic magma and also to the steam produced during the interaction of the magma with underground water. This explosivity can be clearly seen in the cleaf resalte cul out in the "Serie Basáltica Antigua" to some extent penetrated and fragmented by the eruption, The phreatomagmatic character of the eruption is evident because of the existence of accretionary lapilli. The materials emitted are exc1usively of aerial projection: agglomerates, tuffs cinerites. There was no flow of lava. ' Some of the fragments of tuffs as cinerites and pumice are comagmatic. These correspond to salic trachytic phonolitic rocks, which represent one of the last stages of differentiation of the alkaline oceanic magmas. The geochemical character of the materials of the "Caldera del Rey" is characteristic and can be easily distinguished from other nearly salic deposits formed in different cycles.

    En este trabajo se hace el estudio cartográfico, morfológico, petrográfico y geoquímico de la Caldera del Rey. La Caldera del Reyes un edificio volcánico formado por dos maars imbricados. El que se formó en segundo lugar es de mayores dimensiones y destruyó en parte el primero. Ambos aprovecharon para hacer erupción una posible fractura de dirección N 35'"E, de importancia regional en el Archipiélago. La erupción fue de una gran explosividad, que se supone debida, en parte, a la gran importancia de la fase gaseosa del

  3. The two-step monsoon changes of the last deglaciation recorded in tropical Maar Lake Huguangyan,southern China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The concentrations of biogenic silica, total organic carbon, total nitrogen and total hydrogen inferred from the sediments of tropical Maar Lake Huguangyan, southern China, provide a climate record of the last deglaciation with century resolution. The records fully demonstrate the existence of the two-step shape of the last deglaciation in tropic East Asia, and they point out noticeable differences between the low and high latitudes in the Northern Hemisphere. Thus, the Bφlling first warming at the last deglaciation in the low latitude may have preceded that of the high latitude, whereas the cooling of the Younger Dryas occurred synchronously in the two regions. These results likely suggest that the links between the low and high latitude climates in the Northern Hemisphere during this period are complexity.

  4. The Albano Maar Lake high resolution bathymetry and dissolved CO 2 budget (Colli Albani volcano, Italy): Constrains to hazard evaluation

    Science.gov (United States)

    Anzidei, Marco; Carapezza, Maria Luisa; Esposito, Alessandra; Giordano, Guido; Lelli, Matteo; Tarchini, Luca

    2008-04-01

    The Albano Lake is the deepest volcanic lake in Italy (- 167 m) and fills the youngest maar of the quiescent Colli Albani volcano. The lake has undergone significant level changes and lahar generating overflows occurred about 5800 yrs B.P. and likely in 398 b.C., when Romans excavated a tunnel drain through the maar wall. Hazardous lake rollovers and CO 2 release are still possible because the Albano volcano shows active ground deformation, gas emission and periodic seismic swarms. On November 2005, the first high resolution bathymetric survey of the Albano Lake was performed. Here we present the results provided by a Digital Elevation Model and 2-D and 3-D images of the crater lake floor, which is made by coalescent and partly overlapping craters and wide flat surfaces separated by some evident scarps. Submerged shorelines are identified at depths between - 20 m and - 41 m and indicate the occurrence of significant lake level changes, likely between 7.1 and 4.1 ka. The current lake volume is ~ 447.5 × 10 6 m 3 and the total quantity of dissolved CO 2 is 6850 t estimated by chemical analyses of samples collected on May 2006. A decrease of nearly one order of magnitude of the CO 2 dissolved in the lake water below - 120 m, observed from December 1997 to May 2006 (from 4190 to 465 t respectively), has been attributed to lake water overturn. The observed oscillations of the dissolved CO 2 concentrations justify the efforts of monitoring the chemical and physical characteristics of the lake. At present the quantity of dissolved CO 2 is very far from saturation and Nyos-type events cannot presently occur.

  5. The ELSA-Flood-Stack: A reconstruction from the laminated sediments of Eifel maar structures during the last 60 000 years

    Science.gov (United States)

    Brunck, H.; Sirocko, F.; Albert, J.

    2016-07-01

    This study reconstructs the main flood phases in central Europe from event layers in sediment cores from Holocene Eifel maar lakes and Pleistocene dry maar structures. These reconstructions are combined with recent gauge time-series to cover the entire precipitation extremes of the last 60 000 years. In general, Eifel maar sediments are perfectly suited for the preservation of event layers since the deep water in the maar lakes is seasonal anoxic and therefore, bioturbation is low. However, the preservation of annual lamination is only preserved in Holzmaar and Ulmener Maar; the other cores are dated by 14C, magnetostratigraphy, tephra markers and ice core tuning. The cores were drilled in the Eifel region of central western Germany, which represents a climatic homogenous region from Belgium to Poland and all across Central Europe. A total of 233 flood layers over 7.5 mm were detected in all analysed cores. The stratigraphic classification of the flood events follows the newly defined Landscape Evolution Zones (LEZ). The strongest events in the Holocene have occurred during LEZ 1 (0-6000 b2k) in the years 658, 2800 and 4100 b2k. Flood layers in the LEZ 2 (6000-10 500 b2k) are not as frequent as during the LEZ 1, nevertheless, the floods cluster between 6000 and 6500 b2k. Twenty flood layers are found in the LEZ 3 (10 500-14 700 b2k); 11 in LEZ 4 (14 700-21 000 b2k); 15 in LEZ 5 (21 000-28 500 b2k); 34 in LEZ 6 (28 500-36 500 b2k); 8 in LEZ 7 (36 500-49 000 b2k); zero in LEZ 8 (49 000-55 000 b2k) and LEZ 9 (55 000-60 000 b2k). The maximum flood phases during the Pleistocene are at 11 500-17 500 (late glacial and Younger Dryas), 23 000-24 000 (before Greenland Interstadial (GI) 2), 29 000-35 000 (especially between GI 5 and 4) and 44 000-44 500 b2k (transition from GI 12 to 11). The variations in flood dynamics are climatically driven and mainly associated with climate transitions and colder periods, combined with light vegetation. It turns out that low vegetation

  6. The Maar-Diatreme System in a Mixed "Hard/Soft-Rock" Setting: an Example from the Pali Aike Volcanic Field, Argentina

    Science.gov (United States)

    Delpit, S.; Ross, P.

    2009-05-01

    The eruptive processes in diatremes remain poorly understood compared to those at other volcano types, because these processes occur at depth. Except for maar-diatreme volcanoes formed during kimberlitic eruptions, volcanologists agree that these systems are of phreatomagmatic origin. The origin of kimberlitic diatremes is more contentious, but studying non kimberlitic equivalents can be a good approach to better understand kimberlitic diatremes considering their numerous common characteristics. The geometry of maar-diatreme systems is strongly influenced by their setting in "hard-rock" or "soft-rock" environments (Lorenz, 2003, Geolines 15:72-83). Formation of maar-diatreme systems in "hard-rock" environments, like in the West Eifel Volcanic Field of Germany, is largely described in the literature but emplacement in "soft-rock" environments or mixed settings is not. In the case of "hard-rock" environments external water is provided by fracture aquifers. The eruption products are juvenile clasts and country rock fragments. The inner crater walls of the maar, and the diatreme walls, have steep slopes. In the case of "soft- rock" environments, water is contained in the sediment pores and the walls tend to be at lower angles. We recently conducted field work on maars, cinder cones and spatter rings of the Pali Aike Volcanic Field of southern Argentina as part of the Potrok Aike Maar Lake Sediment Archive Drilling Project (PASADO). These Quaternary monogenetic volcanoes were emplaced in a mixed "hard/soft-rock" environment containing young glacial sediments, basaltic lava flows, partly consolidated fluviatile sediments, and older indurated sedimentary rocks. The mixed environment of emplacement is reflected in a phreatomagmatic deposit on the inner slope of a tephra ring exposing some lapilli-tuff layers. The lapilli fraction comprises approximately 40% lithics on average (visual estimate): at least half of the fraction is composed of basaltic lava derived from a pre

  7. Geoheritage values of one of the largest maar craters in the Arabian Peninsula: the Al Wahbah Crater and other volcanoes (Harrat Kishb, Saudi Arabia)

    Science.gov (United States)

    Moufti, Mohammed; Németh, Károly; El-Masry, Nabil; Qaddah, Atef

    2013-06-01

    Al Wahbah Crater is one of the largest and deepest Quaternary maar craters in the Arabian Peninsula. It is NW-SE-elongated, ˜2.3 km wide, ˜250 m deep and surrounded by an irregular near-perpendicular crater wall cut deeply into the Proterozoic diorite basement. Very few scientific studies have been conducted on this unique site, especially in respect to understanding the associated volcanic eruption processes. Al Wahbah and adjacent large explosion craters are currently a research subject in an international project, Volcanic Risk in Saudi Arabia (VORiSA). The focus of VORiSA is to characterise the volcanic hazards and eruption mechanisms of the vast volcanic fields in Western Saudi Arabia, while also defining the unique volcanic features of this region for use in future geoconservation, geoeducation and geotourism projects. Al Wahbah is inferred to be a maar crater that formed due to an explosive interaction of magma and water. The crater is surrounded by a tephra ring that consists predominantly of base surge deposits accumulated over a pre-maar scoria cone and underlying multiple lava flow units. The tephra ring acted as an obstacle against younger lava flows that were diverted along the margin of the tephra ring creating unique lava flow surface textures that recorded inflation and deflation processes along the margin of the post-maar lava flow. Al Wahbah is a unique geological feature that is not only a dramatic landform but also a site that can promote our understanding of complex phreatomagmatic monogenetic volcanism. The complex geological features perfectly preserved at Al Wahbah makes this site as an excellent geotope and a potential centre of geoeducation programs that could lead to the establishment of a geopark in the broader area at the Kishb Volcanic Field.

  8. Eruptive history of the Barombi Mbo Maar, Cameroon Volcanic Line, Central Africa: Constraints from volcanic facies analysis

    Science.gov (United States)

    Tchamabé, Boris; Youmen, Dieudonné; Owona, Sébastien; Issa; Ohba, Takeshi; Németh, Károly; Ngapna, Moussa; Asaah, Asobo; Aka, Festus; Tanyileke, Gregory; Hell, Joseph

    2013-12-01

    his study presents the first and detail field investigations of exposed deposits at proximal sections of the Barombi Mbo Maar (BMM), NE Mt Cameroon, with the aim of documenting its past activity, providing insight on the stratigraphic distribution, depositional process, and evolution of the eruptive sequences during its formation. Field evidence reveals that the BMM deposit is about 126m thick, of which about 20m is buried lowermost under the lake level and covered by vegetation. Based on variation in pyroclastic facies within the deposit, it can be divided into three main stratigraphic units: U1, U2 and U3. Interpretation of these features indicates that U1 consists of alternating lapilli-ash-lapilli beds series, in which fallout derived individual lapilli-rich beds are demarcated by surges deposits made up of thin, fine-grained and consolidated ash-beds that are well-defined, well-sorted and laterally continuous in outcrop scale. U2, a pyroclastic fall-derived unit, shows crudely lenticular stratified scoriaceous layers, in which many fluidal and spindle bombs-rich lapilli-beds are separated by very thin, coarse-vesiculatedash-beds, overlain by a mantle xenolith- and accidental lithic-rich explosive breccia, and massive lapilli tuff and lapillistone. U3 displays a series of surges and pyroclastic fall layers. Emplacement processes were largely controlled by fallout deposition and turbulent diluted pyroclastic density currents under "dry" and "wet" conditions. The eruptive activity evolved in a series of initial phreatic eruptions, which gradually became phreatomagmatic, followed by a phreato-Strombolian and a violent phreatomagmatic fragmentation. A relatively long-time break, demonstrated by a paleosol between U2 and U3, would have permitted the feeding of the root zone or the prominent crater by the water that sustained the next eruptive episode, dominated by subsequent phreatomagmatic eruptions. These preliminary results require complementary studies, such as

  9. A 1000-yr record of environmental change in NE China indicated by diatom assemblages from maar lake Erlongwan

    Science.gov (United States)

    Wang, Luo; Rioual, Patrick; Panizzo, Virginia N.; Lu, Houyuan; Gu, Zhaoyan; Chu, Guoqiang; Yang, Deguang; Han, Jingtai; Liu, Jiaqi; Mackay, Anson W.

    2012-07-01

    Past environmental changes based on diatom relative abundances have been inferred from the maar Lake Erlongwan in northeast China. The limnology of Lake Erlongwan is affected by the strongly seasonal regional climate. The composition of diatom assemblages, in turn, responds to changes in the seasonal duration of ice cover in winter, water-column turnover in spring and autumn, and thermal stratification in summer. Statistical analysis of the sedimentary diatom assemblages reveals three significant stratigraphic zones over the past 1000 yr. The highest abundance of the planktonic species Discostella species occurs between AD 1050 and 1400 and suggests an annual ice-free period of long duration and well-developed summer stratification of the water column. This planktonic diatom peak between ca. AD 1150 and 1200 suggests that this period was the warmest over the past 1000 yr. The interval between AD 1400 and 1800 is marked by a decline in planktonic diatoms and suggests shorter duration of the ice-free season, weaker water stratification and possibly generally cold conditions. After AD 1800 relative abundances of planktonic diatoms, including Puncticulata praetermissa and Asterionella formosa, increase again, which indicates lengthening of the duration of the annual ice-free period and a stronger overturn of the water column. All these data imply that the pattern of the seasons is different between the MWP and the 20th century.

  10. Chemical structure of the organic matter in a Pliocene maar-type shale: Implicated Botryococcus race strains and formation pathways

    Science.gov (United States)

    Derenne, Sylvie; Largeau, Claude; Hetényi, Magdolna; Brukner-Wein, Alice; Connan, Jacques; Lugardon, Bernard

    1997-05-01

    A maar-type Pliocene oil shale from Pula (Hungary) was examined by Scanning and Transmission Electron Microscopy (SEM, TEM) bitumen analysis, spectroscopic analyses (FTIR, solid state 13C NMR) and pyrolytic analyses of insoluble material. The investigated samples, corresponding to the "massive section" of Pula deposit, exhibit TOC values ranging from 18 to 42%, and Rock-Eval analysis indicated that such samples are comprised of low maturity type I kerogen. Electron Microscopy observations confirmed that recognizable microfossils in this organic matter-rich material almost exclusively correspond to Botryococcus braunii colonies, the morphology of which is perfectly retained. Identification of bitumen and pyrolysate constituents (hydrocarbons, ketones, fatty acids), along with morphological and spectroscopic features, indicate (1) that B. braunii provided a major input to the most organic matter-rich section of Pula oil shale; (2) that both the n-alkadienes-producing and the lycopadiene-producing strains ( A and L, respectively) were present; (3) that the selective preservation of the insoluble and non-hydrolysable macromolecules building up B. braunii outer walls was by far the main process in the formation of this material; (4) that such a process, along with B. braunii prolific growth in the favourable environment that occurred in the crater lake, accounts for the very high TOC and oil potential of Pula deposit; and (5) that the condensation of high molecular weight ether lipids from the A race and of some bacterial lipids also likely contributed to Pula kerogen formation.

  11. Rock magnetic studies on sediments from Erlongwan maar lake, Long Gang Volcanic Field, Jilin province, NE China

    Science.gov (United States)

    Frank, Ute

    2007-01-01

    Detailed rock magnetic investigations were carried out on two 23-m-long sediment cores from Erlongwan maar lake, NE China. The completely laminated sediment sequence of the lake is interrupted by 410 graded layers with thicknesses between 0.1 and 150 cm. Magnetite of PSD-size was identified as the main magnetic carrier mineral by temperature-dependent measurements of the saturation magnetization and determination of hysteresis parameters. The minerogenic components in the laminated sediments and the graded layers are nearly identical, and their rock magnetic characteristics reflect the prevailing conditions, anoxic or oxic, during deposition. The most reliable criteria for estimating the availability of oxygen is whether an increase in minerogenic influx is linked to a shift in the magnetic grain size spectrum to coarser (oxic) or finer (anoxic) grains. Comparison of different rock magnetic parameters indicative for magnetic grain size and coercitivity revealed, that the S-ratio which is known to reflect the presence of high coercive minerals, is grain size indicative in sediments with a monomineralic magnetic composition.

  12. The early Holocene optimum inferred from a high-resolution pollen record of Huguangyan Maar Lake in southern China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A high-resolution pollen record of the past 13000 a from Huguangyan Maar Lake reveals the vegetation and environment changes in southern China during the Holocene. It shows that (i) pollen percentage of trees and shrubs reached 56% during the early Holocene (11600―7800 cal a BP), of which the pollen percentage of tropical trees reached a maximum at 9500―8000 cal a BP, reflecting a hot and wet environment; (ii) during the mid-Holocene (7800―4200 cal a BP), the pollen percentage of montane coniferous trees and herbs increased, while the percentage of tropical-subtropical trees decreased, indicating lower temperature and humidity; (iii) in the late Holocene spanning from 4200 to 350 cal a BP, the pollen percentage of herbs and montane conifer increased significantly, indicating a marked decrease of temperature and humidity. Our pollen data reveal that the time period 9500―8000 cal a BP in southern China represents a climatic optimum for the Holocene characterized by hot and wet conditions. This is consistent with the Holocene optimum found in lower latitude regions globally. We speculate that strong insolation might cause the northward migration of the ITCZ and subtropical summer monsoon front, which resulted in an early Holocene optimum in the Huguangyan area. The dry tendency and climate fluctuations of the middle and late Holocene could be associated with a decrease in solar insolation and frequent ENSO event.

  13. How well suited are maar lakes of Madagascar for palaeoenvironmental multi-proxy reconstructions? - First results from shallow seismic, sedimentological and hydrological investigations in Central and Northwest Madagascar.

    Science.gov (United States)

    Daut, Gerhard; Jasmin Krahn, Kim; Rabhobisoa, Jean-Jacques; Ornella Moanazafy, Sergénie; Haberzettl, Torsten; Kasper, Thomas; Mäusbacher, Roland; Schwalb, Antje

    2017-04-01

    Madagascar is well known for its unique flora and fauna which are frequently in the focus of scientific investigations. However, studies on environmental changes in Madagascar linked to Quaternary climatic and/or anthropogenic impact are scarce. The aim of this initial study is to evaluate the potential of maar lakes, situated in different climatic zones of Madagascar, for paleoenvironmental studies and to identify promising coring sites with continuous sediment sequences reaching far back in time. Therefore, in November 2016, a shallow seismic profiling campaign, combined with surface sediment, short gravity core (max. 1.8 m), water and plankton sampling was performed on three target sites. These were two deep maar lakes, i.e., Andraikiba (Central Madagascar, 50m waterdepth) as well as Amparahibe (46,5m waterdepth) and Andampy Ambatoloaka, a shallow (5m waterdepth during low tide) former maar lake now connected to the Ocean (both NW-Madagascar. Vertical water parameter measurements in Lake Amparahibe confirm anoxic bottom conditions, while dissolved oxygen values at the water surface are about 7.9 mg/L (103%). Temperature decreases with depth from 29.3 °C to 27.2 °C, and the lake is slightly alkaline with an electrical conductivity of around 245 µS/cm. Since Andampy Ambatoloaka is connected to the ocean, it shows slightly alkaline conditions as well, electrical conductivity is high ( 57.8 mS/cm) and dissolved oxygen and temperature values are relatively stable at about 8.2 mg/L (104%) and 28.1 °C, respectively. The shallow seismic survey shows an infill with layered sediments of >50 m thickness in Lake Andraikiba. In Lake Amparahibe natural gas in the sediment prevented deeper penetration, however the record shows 10 m of undisturbed, layered sediments in the uppermost part. Sediment cores obtained from both lakes consist of dark brownish to blackish, clayey to silty and partly laminated sediments. High values of magnetic susceptibilities (>1800*10-6 SI) and

  14. Reconstruction of Landscape Evolution Zones (LEZ) from laminated Eifel maar sediments of the last 60 000 years

    Science.gov (United States)

    Sirocko, Frank

    2016-04-01

    Tephra, eolian dust, organic carbon, pollen and botanical macroremains from the dry maar lake structures auf Auel and Dehner are used to synthesize and define Landscape Evolution Zones (LEZ) for the Eifel during the last 60 000 years. LEZ 1-3 reiterate the established succession of vegetation during the Holocene and late glacial. The maximum of the last glaciation (LEZ 4: 14 700 - 23 000 b2k) was characterized by extremely sparse vegetation of some moss and characeae, however, characterized by annual activity of eolian dust. These sediments are generally devoid of clay and sand and reveal no indication of snow-meltwater events; accordingly, the Last Glacial Maximum (LGM) must have been extremely arid in central Europe. The sediments of the subsequent LEZ 5 from 23 000 ‒ 28 500 b2k preserve however distinct layers of clay and coarse sand, which indicates running water with clay in suspension and ephemeral coarse grained fluvial sediment discharge; abundant Ranunculaceae macroremains (used for 14C dating), insects, moss and fungi sclerotia reflect a tundra environment during a time of frequent strong snow melt events. Total carbon content and Betula-Pinus pollen reach increased concentrations during all MIS 3 interstadials that occurred between 28 500 - 36 500 b2k (LEZ 6). Grass pollen and heliophytes indicate a steppe environment with scattered/patchy trees during the interstadials. The stadial phases of LEZ 6 reveal first activity of eolian dust deflation. The opening of the early MIS 3 forested landscape to a steppe occurred with the LEZ 7 - LEZ 6 transition at 36 500 b2k. This is the time when modern man arrived in central Europe; possibly because the vegetation change must have favoured the spread of horse, which was the favoured hunting prey of the modern humans. Accordingly, we postulate that the migration of the modern humans into central Europe could have been mainly driven by climate and vegetation change. The LEZ 7 encompassing the time interval from 36

  15. New palynology-based astronomical and revised 40Ar/39Ar ages for the Eocene maar lake of Messel (Germany)

    Science.gov (United States)

    Lenz, Olaf K.; Wilde, Volker; Mertz, Dieter F.; Riegel, Walter

    2015-04-01

    The annually laminated oil shale from the Eocene maar lake at Messel (Federal State of Hessen, Germany) provides unique paleoenvironmental data for a time interval of ~640 ka during the Paleogene greenhouse phase. As a consequence of orbitally controlled changes in the vegetation in the vicinity of the lake, the lacustrine laminites can now be astronomically tuned. Dating is based on the short eccentricity amplitude modulations of the regional pollen rain and their correlation to the astronomical La2010a/La2010d solutions in combination with a revised 40Ar/39Ar age of a basalt fragment from a lapilli tuff section below the first lacustrine sediments. Depending on different newly suggested ages for the Fish Canyon sanidine used as monitor for neutron irradiation, the age for the eruption at Messel is between 48.27 ± 0.22 and 48.11 ± 0.22 Ma. This allows for the first time the exact correlation of a Paleogene lacustrine sequence to the marine record in Central Europe. The Messel oil shale becomes now slightly older than previously assumed and includes the Ypresian/Lutetian boundary that moves the base of the European Land Mammal Age Geiseltalian (MP 11) into the Lower Eocene. This opens a window for establishing an independent chronostratigraphic framework for Paleogene terrestrial records and their correlation to the marine realm. Furthermore, the study reveals that higher amounts of pollen from "wet" and thermophilous plants indicate less seasonal and more balanced precipitation and slightly higher temperatures during a well-expressed eccentricity minimum.

  16. Cretaceous basaltic phreatomagmatic volcanism in West Texas: Maar complex at Peña Mountain, Big Bend National Park

    Science.gov (United States)

    Befus, K. S.; Hanson, R. E.; Lehman, T. M.; Griffin, W. R.

    2008-06-01

    A structurally complex succession of basaltic pyroclastic deposits produced from overlapping phreatomagmatic volcanoes occurs within Upper Cretaceous floodplain deposits in the Aguja Formation in Big Bend National Park, West Texas. Together with similar basaltic deposits recently documented elsewhere in the Aguja Formation, these rocks provide evidence for an episode of phreatomagmatic volcanism that predates onset of arc magmatism in the region in the Paleogene. At Peña Mountain, the pyroclastic deposits are ≥ 70 m thick and consist dominantly of tabular beds of lapillistone and lapilli tuff containing angular to fluidal pyroclasts of altered sideromelane intermixed with abundant accidental terrigenous detritus derived from underlying Aguja sediments. Tephra characteristics indicate derivation from phreatomagmatic explosions involving fine-scale interaction between magma and sediment in the shallow subsurface. Deposition occurred by pyroclastic fall and base-surge processes in near-vent settings; most base-surge deposits lack tractional sedimentary structures and are inferred to have formed by suspension sedimentation from rapidly decelerating surges. Complexly deformed pyroclastic strata beneath a distinct truncation surface within the succession record construction and collapse of an initial volcano, followed by a shift in the location of the conduit and excavation of another maar crater into Aguja strata nearby. Preserved portions of the margin of this second crater are defined by a zone of intense soft-sediment disruption of pyroclastic and nonvolcanic strata. U-Pb isotopic analyses of zircon grains from three basaltic bombs in the succession reveal the presence of abundant xenocrysts, in some cases with ages > 1.0 Ga. The youngest concordant analyses for all three samples yield a weighted mean age of 76.9 ± 1.2 Ma, consistent with the presence of Late Campanian vertebrate fossils in the upper Aguja Formation. We infer that the volcanism is related to the

  17. Huguangyan Maar Lake (SE China): A solid record of atmospheric mercury pollution history in a non-remote region

    Science.gov (United States)

    Zeng, Yan; Chen, Jingan; Yang, Yongqiong; Wang, Jianxu; Zhu, Zhengjie; Li, Jian

    2017-10-01

    Mercury is a highly toxic metal that can cause harm to environment and human health. As atmospheric deposition is the main source of total Hg input to aquatic system in remote and pristine regions, almost all the studies on atmospheric Hg pollution history concentrated in these areas, while the studies in non-remote areas are much limited, especially for the long history records. In this study, Huguangyan Maar Lake, an undisturbed lake system at low altitude in China, was selected to reconstruct the atmospheric mercury pollution history. Variation patterns of TOC, Hg and non-residual Sr in the sediment core indicated that, compared to the direct atmospheric Hg deposition, the effect of either Hg scavenging from water column by algae or the catchment inputs of previously deposited Hg on the Hg accumulation in the lake sediment was limited. The sediment Hg content in Huguangyan Lake was mainly controlled by the atmospheric Hg deposition, and thus accurately reflected the atmospheric Hg pollution history. The Hga (Hg content from atmospheric deposition) in Huguangyan Lake presented a comparable variation pattern to that in remote sites. It had the same variation trend as the global atmospheric Hg before 1950 CE, which could be attributed to the Industrial Revolution. After that, it was mainly controlled by Hg emissions from Asian countries. The variation of Hga also indicated that atmospheric Hg deposition accelerated significantly since 2000 CE. This study, along with other investigations in remote sites in China, showed that the sediment Hg in Huguangyan Lake responded to the atmospheric Hg pollution more sensitively than in the alpine regions. It should be noted that, the more intensive acceleration of Hg deposition in Huguangyan Lake may imply that the South of China suffered from much more serious atmospheric Hg pollution than previous studies revealed.

  18. Geochemical characterization of a Quaternary monogenetic volcano in Erciyes Volcanic Complex: Cora Maar (Central Anatolian Volcanic Province, Turkey)

    Science.gov (United States)

    Gencalioglu-Kuscu, Gonca

    2011-11-01

    Central Anatolian Volcanic Province (CAVP) is a fine example of Neogene-Quaternary post-collisional volcanism in the Alpine-Mediterranean region. Volcanism in the Alpine-Mediterranean region comprises tholeiitic, transitional, calc-alkaline, and shoshonitic types with an "orogenic" fingerprint. Following the orogenic volcanism, subordinate, within-plate alkali basalts ( sl) showing little or no orogenic signature are generally reported in the region. CAVP is mainly characterized by widespread calc-alkaline andesitic-dacitic volcanism with orogenic trace element signature, reflecting enrichment of their source regions by subduction-related fluids. Cora Maar (CM) located within the Erciyes pull-apart basin, is an example to numerous Quaternary monogenetic volcanoes of the CAVP, generally considered to be alkaline. Major and trace element geochemical and geochronological data for the CM are presented in comparison with other CAVP monogenetic volcanoes. CM scoria is basaltic andesitic, transitional-calc-alkaline in nature, and characterized by negative Nb-Ta, Ba, P and Ti anomalies in mantle-normalized patterns. Unlike the "alkaline" basalts of the Mediterranean region, other late-stage basalts from the CAVP monogenetic volcanoes are classified as tholeiitic, transitional and mildly alkaline. They display the same negative anomalies and incompatible element ratios as CM samples. In this respect, CM is comparable to other CAVP monogenetic basalts ( sl), but different from the Meditterranean intraplate alkali basalts. Several lines of evidence suggest derivation of CM and other CAVP monogenetic basalts from shallow depths within the lithospheric mantle, that is from a garnet-free source. In a wider regional context, CAVP basalts ( sl) are comparable to Apuseni (Romania) and Big Pine (Western Great Basin, USA) volcanics, except the former have depleted Ba contents. This is a common feature for the CAVP volcanics and might be related to crustal contamination or source

  19. Valley pond and ignimbrite veneer deposits in the small-volume phreatomagmatic `Peperino Albano' basic ignimbrite, Lago Albano maar, Colli Albani volcano, Italy: influence of topography

    Science.gov (United States)

    Giordano, G.; De Rita, D.; Cas, R.; Rodani, S.

    2002-11-01

    The ca. 23-ka, small-volume, basic phreatomagmatic Peperino Albano ignimbrite, from the polygenetic Albano maar (Colli Albani volcano, central Italy) shows valley pond facies as well as veneer deposits along the maar rim and along topographic ridges. Valley pond facies is characterised mainly by massive structure and chaotic texture and can be up to 30 m thick. Veneer deposit facies is characterised by parallel to low-angle cross-stratified bedforms alternating fines-depleted lapilli-sized layers, and massive, matrix-supported beds. Occurrence of uncharred wood remains and accretionary lapilli suggests temperature of emplacement comprised between 246° and 100°C. We have interpreted the lateral facies variations in terms of temporal and spatial variations of the sediment supply from the transport system to the depositional system of the pyroclastic flow. Ignimbrite veneer facies at the maar rim may reflect pulsatory eruption dynamics, whereas valley pond facies may reflect the bulking of the pyroclastic flow inside the valleys and consequent high sedimentation rates. Ignimbrite veneer facies at topographic ridges has been interpreted to reflect detachment processes of more concentrated undercurrents draining within valleys from the more dilute upper part of the pyroclastic flow that climbs the ridges. The present interpretation suggests that processes of pyroclastic flow transformation downcurrent and induced by topography are not necessarily peculiar of hot, high-mobility pyroclastic density currents. The more likely source of water interacting with magma is interpreted to be groundwater contained within the karstic aquifer located at approximately 1 km below the ground level. This is inferred by both the large amount of limestone xenoliths present in the Peperino Albano and the absence of vesicular juvenile clasts, the latter implying that magma-water interaction occurred before gas exolution processes were significant.

  20. The Albano maar lake (Colli Albani Volcano, Italy): recent volcanic activity and evidence of pre-Roman Age catastrophic lahar events

    Science.gov (United States)

    Funiciello, R.; Giordano, G.; De Rita, D.

    2003-04-01

    The evaluation of volcanic hazard in the Roman hinterland related to the quiescent Colli Albani Volcano has recently been the subject of renewed attention and several interpretations by many authors. However, very little was known of the recent history of the volcano, making such interpretations rather speculative. The most recent activity of Colli Albani Volcano originated from the Albano polygenetic maar lake, which erupted several phreatomagmatic units, the most recent of which, the Peperino Albano ignimbrite, has been dated at around 25 ka. An area of several square kilometers centered around Albano Lake is presently the site of shallow and frequent seismic activity and gaseous emission as well as hydrothermal activity and is therefore considered the most prone to geologic hazards. This paper presents new stratigraphic and geomorphologic data as well as age determinations that allow rejuvenation of the most recent activity of the Colli Albani Volcano, and particularly the Albano maar lake, to the Holocene. This study allows for the first time to identify a potential hazard related to the Albano maar lake withdrawal interpreted to be related to endogenous causes, namely CO 2 emission. The main results of the study are: (1) the Peperino Albano is not, as is generally believed, the last phreatomagmatic eruption from the Colli Albani Volcano; a previously unrecognized phreatomagmatic surge deposit has been identified overlying the paleosol at the top of the Peperino Albano and related lahar deposits; (2) two lahar deposits separated by paleosols top the stratigraphic succession and are dispersed only to the NW, corresponding to the lowest point of the maar rim, indicating that catastrophic hydrologic events occurred at the Albano Lake in recent times; rapid and substantial lake-level variations and lake withdrawal are reported by Roman historians and recorded by the stratigraphy of the Albano Lake lacustrine sediments; (3) microfracturing related to seismic energy

  1. Absurdist trends in american children's theatre : the case of "Noodle Doodle Box" by Paul Maar (1972) and "In a room somewhere" by Susan Zeder (1985)

    OpenAIRE

    Cirella-Urrutia, Anne

    2000-01-01

    Anne Cirella-Urrutia evalúa el nacimiento del movimiento del absurdo en la historia del teatro juvenil americano. En particular, el artículo analiza el uso de técnicas del absurdo en las obras Noodle Doodle Box, escrita en 1972 por el dramaturgo alemán Paul Maar, y In a Room Somewhere, por la dramaturga americana Susan Zeder, actuada en 1985. La autora señala cómo estas obras adaptan fuentes familiares del Absurdo para ajustarse a su audiencia, con esta innovación estilística. Además, el a...

  2. Craters on Earth, Moon, and Mars - Multivariate classification and mode of origin

    Science.gov (United States)

    Pike, R. J.

    1974-01-01

    Testing extraterrestrial craters and candidate terrestrial analogs for morphologic similitude is treated as a problem in numerical taxonomy. According to a principal-components solution and a cluster analysis, 402 representative craters on the Earth, the Moon, and Mars divide into two major classes of contrasting shapes and modes of origin. Craters of net accumulation of material (cratered lunar domes, Martian calderas, and all terrestrial volcanoes except maars and tuff rings) group apart from craters of excavation (terrestrial meteorite impact and experimental explosion craters, typical Martian craters, and all other lunar craters). Maars and tuff rings belong to neither group but are transitional. The classification criteria are four independent attributes of topographic geometry derived from seven descriptive variables by the principal-components transformation. Morphometric differences between crater bowl and raised rim constitute the strongest of the four components.

  3. Diagenetic effects on magnetic minerals in a Holocene lacustrine sediment core from Huguangyan maar lake, southeast China

    Science.gov (United States)

    Wu, Xudong; Wang, Yong; Bian, Liu; Shen, Ji

    2016-09-01

    Post-depositional reductive diagenesis usually results in partial or entire cleansing of the pristine palaeomagnetic signal, therefore, its intensity is important to be assessed for sediments that are in the purpose of retrieving palaeomagnetic information. Grain size, rock magnetic and geochemical studies on the entire core, along with scanning electron microscope observations and X-ray diffraction analyses for representative samples were carried out on a Holocene sediment core retrieved from the deep water part of Huguangyan maar lake (HGY), southeast China. The pristine magnetic mineral assemblage of the studied core is domianted by superparamagnetic (SP) and stable single domain titanomagnetite, and high coercivity minerals are not detectable. Based on down-core variations of the average grain size (MZ), total organic carbon (TOC), detrital elements (Al, Ti, Fe and Mn) and the concentration and mineralogy of magnetic minerals, the studied core could be divided into three subsections. The uppermost subsection is the least affected by diagenesis, with detrital titanomagnetite as the dominant magnetic mineral. This is owing to low TOC contents, but high detrital input generated by weak Asian summer monsoon intensity during the late Holocene. The intermediate subsection shows down-core progressively enhanced dissolution of detrital titanomagnetite, and concomitant formation of authigenic pyrite and siderite, which indicates down-core progressively enhanced diagenesis generated by down-core progressive increasing TOC content, but decreasing detrital input as the result of down-core progressively strengthened Asian summer monsoon intensity. The pristine magnetic mineral assemblage has been profoundly modified in the lowermost subsection. At certain positions of the lowermost subsection, detrital titanomagnetite has been even completely dissolved via diagenesis, giving place to authigenic pyrite and siderite. High TOC content, but low detrital input generated from

  4. The Magnetic Properties of Indonesian Lake Sediment: A Case Study of a Tectonic Lake in South Sulawesi and Maar Lakes in East Java

    Directory of Open Access Journals (Sweden)

    Gerald Tamuntuan

    2010-03-01

    Full Text Available Magnetic properties of sediments from two different environmental settings in Indonesia have been studied using rock magnetic methods and scanning electron microscopy (SEM. In the first setting, magnetic measurements were conducted on core sediments from two maar lakes in East Java (Lakes Lading and Bedali that represent very confined environments where sediments are derived mainly from rocks and soils within the craters. In the second setting, similar measurements were obtained on core sediment from Lake Matano, a cryptodepression lake in tectonically active South Sulawesi where the area around the lake is dominated by highly magnetic lateritic soils. The results show that the predominant magnetic mineralogy in sediments from Lakes Lading, Bedali, as well as Matano is pseudo-single domain (PSD magnetite (Fe3O4. Compared to that of Lake Matano, the maar lake sediments of Lakes Lading and Bedali have higher magnetic susceptibility as well as high intensity of ARM and SIRM. Variations in magnetic susceptibility in all core sediments are controlled mainly by the concentration of magnetic minerals. The homogeneity of magnetic minerals in these three lakes sediment provides an excellent setting for interpreting paleoclimatic signals as they will be recorded as anomalies of magnetic susceptibility.

  5. Kleine retentie: ja, maar ...

    NARCIS (Netherlands)

    Jaskula-Joustra, A.; Mioduszewski, W.; Plaza, W.; Bakel, van J.

    2005-01-01

    Het vasthouden en bergen van water wordt heel vaak genoemd als een maatregel tegen overstroming, hoewel hieraan veel haken en ogen zitten. Kan vasthouden werkelijk een bijdrage leveren aan het bestrijden van hoogwater? Om hierover van mening te kunnen wisselen ging de NVA- werkgroep Twinning Polen s

  6. Oskus kuulata / Ellu Maar

    Index Scriptorium Estoniae

    Maar, Ellu

    2007-01-01

    Clare Charnley näitus "Keelte and" Hobusepea galeriis kuni 17. XII. Projektis osalevad kaaskunstnikud, Eestist Katrin Kivimaa. Avamisel esitleti raamatut "So communications : translating each other's words"

  7. Luchtwassers effectief, maar kostbaar

    NARCIS (Netherlands)

    Middelkoop, van J.H.

    1995-01-01

    Het PP onderzoekt naast verschillende vormen van emissiebeperkende huisvestingssystemen ook luchtwassers op hun effectiviteit en praktische inpasbaarheid. Het blijkt dat een biochemische luchtwasser de ammoniakemissie met 80procent kan verminderen

  8. Oskus kuulata / Ellu Maar

    Index Scriptorium Estoniae

    Maar, Ellu

    2007-01-01

    Clare Charnley näitus "Keelte and" Hobusepea galeriis kuni 17. XII. Projektis osalevad kaaskunstnikud, Eestist Katrin Kivimaa. Avamisel esitleti raamatut "So communications : translating each other's words"

  9. Thermoluminescence dating: study of a possible chronological correlation between the maar of la Vestide-du-Pal and a tephra layer from la Baume-Moula-Guercy (Ardeche, France); Datation par thermoluminescence: etude d'une correlation chronologique possible entre le maar de la Vestide-du-Pal et un niveau de tephra de La Baume-Moula-Guercy (Ardeche, France)

    Energy Technology Data Exchange (ETDEWEB)

    Sanzelle, S.; Pilleyre, Th.; Montret, M.; Fain, J.; Miallier, D. [Universite Blaise Pascal, Clermont-Ferrand II, (CNRS), 63 - Aubiere (France); Camus, G.; Goer de Herve, A. de [Universite Blaise Pascal, Centre de Recherches volcanologiques, 63 - Clermont-Ferrand (France); Defleur, A. [Universite de la Mediterranee, Faculte de Medecine secteur nord, Lab. d' anthropologie, UMR 6569, 13 - Marseille (France)

    2000-04-01

    The origin of an ash level sampled in the archaeological site 'La Baume-Moula-Guercy' (Soyons, Ardeche, France), was previouslyattributed to the maar 'La Vestide-du Pal' (Bas-Vivarais, Massif Central, France). In order to test this assumption by means of absolute chronology, thermoluminescence dating was applied to both sites. The results, 72{+-}12 ka for La Baume-Moula and 49{+-} 7 ka for La Vestide-du-Pal were not in agreement. The initial assumption must then be questioned. (authors)

  10. The ELSA-Vegetation-Stack: Reconstruction of Landscape Evolution Zones (LEZ) from laminated Eifel maar sediments of the last 60,000 years

    Science.gov (United States)

    Sirocko, F.; Knapp, H.; Dreher, F.; Förster, M. W.; Albert, J.; Brunck, H.; Veres, D.; Dietrich, S.; Zech, M.; Hambach, U.; Röhner, M.; Rudert, S.; Schwibus, K.; Adams, C.; Sigl, P.

    2016-07-01

    Laminated sediment records from several maar lakes and dry maar lakes of the Eifel (Germany) reveal the history of climate, weather, environment, vegetation, and land use in central Europe during the last 60,000 years. The time series of the last 30,000 years is based on a continuous varve counted chronology, the MIS3 section is tuned to the Greenland ice - both with independent age control from 14C dates. Total carbon, pollen and plant macrofossils are used to synthesize a vegetation-stack, which is used together with the stacks from seasonal varve formation, flood layers, eolian dust content and volcanic tephra layers to define Landscape Evolution Zones (LEZ). LEZ 1 encompasses the landscape dynamics of the last 6000 years with widespread human influence. The natural oak and hazel forests of the early Holocene back to 10,500 b2k define LEZ 2. LEZ 3, the late glacial between 10,500 and 14,700 b2k, shows the development of a boreal forest with abundant grass and shallow water biomass in the lakes. The maximum of the last glaciation (LEZ 4: 14,700-23,000 b2k) was characterized by sparse vegetation of moss and characeae. These sediments are generally devoid of clay and sand and reveal no indication of snow-meltwater events. Accordingly, the Last Glacial Maximum (LGM) must have been extremely arid in central Europe. The sediments of the subsequent LEZ 5 from 23,000-28,500 b2k preserve distinct layers of clay and coarse sand, which indicates running water with clay in suspension and ephemeral coarse-grained fluvial sediment discharge. Abundant Ranunculaceae macroremains (used for 14C dating), insects, moss and fungi sclerotia reflect a tundra environment during a time of frequent strong snowmelt events. Total carbon content, Betula-Pinus pollen and diatoms reach increased concentrations during Marine Isotope Stage (MIS) 3 interstadials that occurred between 28,500 and 36,500 b2k (LEZ 6). The entire MIS3 interstadials are well documented in the organic carbon record

  11. Drill Core Mineral Analysis by Means of the Hyperspectral Imaging Spectrometer HySpex, XRD and Asd in Proximity of the MÝTINA Maar, Czech Republic

    Science.gov (United States)

    Koerting, F.; Rogass, C.; Kaempf, H.; Lubitz, C.; Harms, U.; Schudack, M.; Kokaly, R.; Mielke, C.; Boesche, N.; Altenberger, U.

    2015-12-01

    Imaging spectroscopy is increasingly used for surface mapping. Therefore different expert systems are being utilized to identify surface cover materials. Those expert systems mainly rely on the spectral comparison between unknown and library spectra, but their performances were only limited qualified. This study aims on the comparative analysis of drill core samples from the recently discovered maar system in the Czech Republic. Drill core samples from the surrounding area of the Mýtina maar were analyzed by X-Ray diffraction (XRD) and the hyperspectral spectrometer HySpex. Additionally, soil samples were measured in-situ by the ASD FieldSpec4 and in the laboratory by the HySpex VNIR/SWIR spectrometer system. The data was then analyzed by the MICA-algorithm and the results were compared to the results of the XRD -analysis. The XRD-analysis served here as validation basis. The results of the hyperspectral and the XRD analyses were used to densify a volcanic map that also integrates in-situ soil measurements in the surrounding area of Mýtina. The comparison of the XRD- and solaroptical remote sensing results showed a good correlation of qualified minerals if the soil organic carbon content was significantly low. Contrary to XRD, smectites and muscovites were also straightforward identified that underlines the overall performance of the approach to identify minerals. Basically, in this work an operable approach is proposed that enables the fast, repeatable and detailed analysis of drill cores, drill core samples and soil samples and, hence, provides a higher performance than state-of-the-art XRD-analyses.

  12. The Last Glacial Maximum in the Northern European loess belt: Correlations between loess-paleosol sequences and the Dehner Maar core (Eifel Mountains)

    Science.gov (United States)

    Zens, Joerg; Krauß, Lydia; Römer, Wolfgang; Klasen, Nicole; Pirson, Stéphane; Schulte, Philipp; Zeeden, Christian; Sirocko, Frank; Lehmkuhl, Frank

    2016-04-01

    The D1 project of the CRC 806 "Our way to Europe" focusses on Central Europe as a destination of modern human dispersal out of Africa. The paleo-environmental conditions along the migration areas are reconstructed by loess-paleosol sequences and lacustrine sediments. Stratigraphy and luminescence dating provide the chronological framework for the correlation of grain size and geochemical data to large-scale climate proxies like isotope ratios and dust content of Greenland ice cores. The reliability of correlations is improved by the development of precise age models of specific marker beds. In this study, we focus on the (terrestrial) Last Glacial Maximum of the Weichselian Upper Pleniglacial which is supposed to be dominated by high wind speeds and an increasing aridity. Especially in the Lower Rhine Embayment (LRE), this period is linked to an extensive erosion event. The disconformity is followed by an intensive cryosol formation. In order to support the stratigraphical observations from the field, luminescence dating and grain size analysis were applied on three loess-paleosol sequences along the northern European loess belt to develop a more reliable chronology and to reconstruct paleo-environmental dynamics. The loess sections were compared to newest results from heavy mineral and grain size analysis from the Dehner Maar core (Eifel Mountains) and correlated to NGRIP records. Volcanic minerals can be found in the Dehner Maar core from a visible tephra layer at 27.8 ka up to ~25 ka. They can be correlated to the Eltville Tephra found in loess section. New quartz luminescence ages from Romont (Belgium) surrounding the tephra dated the deposition between 25.0 + 2.3 ka and 25.8 + 2.4 ka. In the following, heavy minerals show an increasing importance of strong easterly winds during the second Greenland dust peak (~24 ka b2k) correlating with an extensive erosion event in the LRE. Luminescence dating on quartz bracketing the following soil formation yielded ages of

  13. Environment and climate of the last 51,000 years - new insights from the Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO)

    Science.gov (United States)

    Zolitschka, B.; Anselmetti, F.; Ariztegui, D.; Corbella, H.; Francus, P.; Lücke, A.; Maidana, N. I.; Ohlendorf, C.; Schäbitz, F.; Wastegård, S.

    2013-07-01

    In this introductory paper we summarize the history and achievements of the Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO), an interdisciplinary project embedded in the International Continental Scientific Drilling Program (ICDP). The stringent multiproxy approach adopted in this research combined with radiocarbon and luminescence dating provided the opportunity to synthesize a large body of hydrologically relevant data from Laguna Potrok Aike (southern Patagonia, Argentina). At this site, lake level was high from 51 ka until the early Holocene when the Southern Hemisphere Westerlies (SHW) were located further to the north. At 9.3 ka cal. BP the SHW moved southward and over the latitude of the study area (52°S) causing a pronounced negative water balance with a lake level decrease of more than 50 m. Two millennia later, the SHW diminished in intensity and lake level rose to a subsequent maximum during the Little Ice Age. Since the 20th century, a strengthening of the SHW increased the evaporative stress resulting in a more negative water balance. A comparison of our data with other hydrological fluctuations at a regional scale in south-eastern Patagonia, provides new insights and also calls for better chronologies and high-resolution records of climate variability.

  14. 湖光岩火山灰古剂量的两种计算比较%Comparison of Calculated Paleodoses of Volcano Ash beside Huguang Maar Lake

    Institute of Scientific and Technical Information of China (English)

    丁萍; 熊正烨; 王文华; 李永强; 唐强; 黄存友

    2011-01-01

    Based on the thermoluminescence (TL) data, the paleodose of volcanic ash near Huguangyan Maar Lake was calculated with sensitized revision technique. The calculated paleodose depending on TL about 330 ℃ is (75.3±4.8) Gy, while the calculated paleodose depending on TL about 400 ℃ is (115±8)Gy. A physical model is set up to analyze the difference between the two results.%根据热释光测量结果,用敏化修正方法计算了湖光岩玛珥湖周围岩洞内的火山灰的古剂量.用330℃附近的热释光峰作为剂量响应计算出的结果为(75.3±4.8)Gy,但取400℃附近的热释光作为剂量响应计算出的结果为(115±8)Gy.建立物理模型分析了这两种结果不同的内在原因.

  15. 锡林浩特-阿巴嘎火山群内的玛珥式火山%MAARS IN XILINHOT-ABAGA VOLCANIC CLUSTER

    Institute of Scientific and Technical Information of China (English)

    王锡娇; 白志达; 谭琳; 吴之理; 王妍

    2012-01-01

    Xilinhot-Abaga volcanic cluster is located in Xilin Gol League of Inner Mongolia Autonomous Region , and it is in the centre of Daxinganling-Datong volcanic eruption belt. There are more than 300 Quaternary basaltic volcanoes of different types. Maars are found for the first time there,with Haotewula in the southeast of Abagaqi, Chelewula and Esigewula in the northwest of Abagaqi being the most representative. They all have large scale,and the diameter of cone is generally 3 ~4km,the largest is up to 6. 5km. They have relatively intact structure,similar two-ringed mountain landscape and obvious phreas-ic eruption which contains strong phreatomagmatic eruption at the earlier stage, later weak magmatic e-ruption and at last basaltic lava overflowing phase. This eruption sequence reflects the interaction between magma and groundwater, the change in intrusive speed and the flow-out rate of magma. The sand and gravel of Middle Pleistocene depositing in the valley are covered by basal surge deposits. The TL age of sandstone-shale inclusion which was found in the spattering deposits close to crater is(0. 112± 0. 0096) Ma, which indicates that the eruption times of the maars are early Late Pleistocene.%锡林浩特-阿巴嘎火山群位于内蒙古自治区锡林郭勒盟,处于大兴安岭-大同新生代火山喷发带中段.火山群内发育300余座不同类型的第四纪玄武质火山,其中玛珥式火山属首次发现,以阿巴嘎旗东南部的浩特乌拉、西北部的车勒乌拉和额斯格乌拉玛珥式火山最具代表性,其火山规模较大,锥体直径一般为3~4km,大者约6.5km.火山结构较完整,具有相似的双轮山地貌景观和明显的阶段性喷发过程,喷发阶段早期为强烈的射汽-岩浆爆发,晚期均转变为弱岩浆爆发,最后为玄武质熔岩流的溢出.这种喷发序列反映了岩浆与水相互作用以及岩浆上升速度和溢出率变化的过程.火山喷发形成的基浪堆积物覆盖在中更新

  16. Diatom responses to limnological and climatic changes at Ribains Maar (French Massif Central) during the Eemian and Early Würm

    Science.gov (United States)

    Rioual, Patrick; Andrieu-Ponel, Valérie; de Beaulieu, Jacques-Louis; Reille, Maurice; Svobodova, Hélèna; Battarbee, Richard W.

    2007-06-01

    High-resolution diatom analysis was carried out to assess the limnological and climatic changes that took place at Ribains maar (French Massif Central) during the Late Pleistocene (˜131-˜105 ka BP), with a focus on the Eemian interglacial in particular. Numerical analyses were used to show that most of the variability in the fossil diatom assemblages was due to climate independently from the changes in the lake catchment vegetation (as represented by pollen data). Diatom-based quantitative reconstructions of the past limnological conditions, as well as a comprehensive literature review on the auto-ecological requirements for the principal diatom taxa, were used to interpret the record. An absolute time-scale for the sequence was derived by matching the major pollen shifts with the radiometrically dated changes in oxygen isotopes observed in Italian stalagmites. This study shows that at Ribains maar, the transition from the Riss (=Saalian) Glacial to the Eemian interglacial was marked by a gradual increase in the contribution of spring-blooming diatom species, indicating a longer growing season and milder winter/spring conditions at that time. A short cooling event interrupts this trend and may correspond to a stadial. At the start of the Eemian a peak in benthic taxa and the suppression of spring-blooming flora probably reflects the effects of deglaciation on the catchment. During the Eemian interglacial itself three main phases were distinguished within the diatom record. The first phase (˜8000 years in duration) was dominated by Stephanodiscus minutulus, which suggests that intense mixing in the water-column took place during spring. The pollen record was simultaneously dominated by Quercus and Corylus that typify this phase as the climatic optimum of the Eemian. The second phase, almost equal in duration to the first phase (˜7000 years), is generally dominated by Cyclotella taxa and suggests a less productive lake and much reduced period of spring mixing

  17. Magnetic Fabric and Implications For Emplacement Processes of The Phreatomagmatic Peperino Albano Basic Ignimbrite, Lago Albano Maar, Colli Albani Volcano, Italy

    Science.gov (United States)

    Porreca, M.; Mattei, M.; Funiciello, R.; Giordano, G.; de Rita, D.

    We carried out anisotropy of magnetic susceptibility (AMS) analysis on the small vol- ume, basic phreatomagmatic Peperino Albano (PA) ignimbrite erupted about 25 ka, from the polygenetic Albano maar (Colli Albani volcano, central Italy), and from the overlying succession of lahars deposits cropping out in proximity of the city of Rome. The AMS in the PA shows different magnetic fabrics according to different facies such as the intracrater facies, the valley pond and the veneer facies, suggesting that the magnetic fabric is related to different emplacement mechanisms. In the intracrater facies, the magnetic lineation is poorly defined, although clearly radial with respect to the vent. In the valley pond facies, the magnetic lineation is well defined and its imbrication permits to define the direction of flow, which is oriented predominantly downcurrent. The presence of magnetic foliation is characteristic of the veneer facies along topographic ridges, and the imbrication of the foliation indicates paleo-flow di- rections radial to the vent. The distinction of facies is further confirmed by means of values of magnetic susceptibility. These magnetic facies differences have been inter- preted to reflect temporal and spatial variations of depositional and transport systems of the PA pyroclastic flow. Ignimbrite veneer facies may reflect dilute and turbulent flow unsteadiness related to the eruption dynamics, decoupled to more concentrated flow draining inside the valleys and characterised by high sedimentation rates (valley pond facies). This study demonstrates like AMS is a powerful indicator of the pre- ferred orientation of minerals and provides information about the process leading to the transport and deposition of pyroclastic rocks.

  18. Reconstructing hydroclimatic variations using compound-specific hydrogen isotope analysis of biomarkers from a maar lake in the Central Highlands, Vietnam

    Science.gov (United States)

    Doiron, Kelsey; Stevens, Lora; Sauer, Peter

    2017-04-01

    Monsoonal variation in Southeast Asia affects a significant portion of the global population, but knowledge regarding response of the monsoon system to changing boundary conditions is limited. The paleoclimatic tool of compound-specific isotope analysis(CSIA) provides the ability to reconstruct past precipitation using a diverse set of biomarkers preserved in the sedimentary record. Limited proxies in tropical southeast Asia and difficult site access have led to a deficit in paleoclimate records. Ia M'He (14˚ 10'45" N, 107˚ 52' E) is a shallow volcanic crater (maar) lake, approximately 57 ha, located in the Central Highlands of Vietnam. Precipitation in the Central Highlands is sensitive to reorganizations of major climatic features, such as the migration of the ITCZ and the coupled Indo-Asian monsoon, ENSO and related shifts in the Pacific Walker Circulation and typhoon frequency. To examine this complex behavior, this pilot study aims to provide a 500-year record of effective moisture inferred from CSIA of hydrogen isotopes on biomarkers. Carbon/nitrogen ratios and carbon isotope ratios indicate that bulk organic matter is a combination of algae and C3 vegetation, offering the potential to use compound-specific hydrogen isotopes of aquatic and terrestrial organic matter in tandem. Preliminary analysis of the core shows dominant alkane chain lengths of C27 and C29, associated with terrestrial plant leaf waxes. The hydrogen isotope ratios of the plant wax components provide a proxy for paleo precipitation in a region where rainfall and droughts heavily influence population dynamics and create social discord. The CSIA record is expected to correlate with records from northern Vietnam, the South China Sea and Indonesia, with greater precipitation during the Little Ice Age. The degree to which evaporative modification of lake water (i.e., seasonal drying) occurs will be estimated by comparing the terrestrial CSIA values indicative of meteoric water with aquatic CSIA

  19. Hydrological and ecological changes in western Europe between 3200 and 2000 years BP derived from lipid biomarker δD values in lake Meerfelder Maar sediments

    Science.gov (United States)

    Rach, O.; Engels, S.; Kahmen, A.; Brauer, A.; Martín-Puertas, C.; van Geel, B.; Sachse, D.

    2017-09-01

    One of the most significant Late Holocene climate shifts occurred around 2800 years ago, when cooler and wetter climate conditions established in western Europe. This shift coincided with an abrupt change in regional atmospheric circulation between 2760 and 2560 cal years BP, which has been linked to a grand solar minimum with the same duration (the Homeric Minimum). We investigated the temporal sequence of hydroclimatic and vegetation changes across this interval of climatic change (Homeric climate oscillation) by using lipid biomarker stable hydrogen isotope ratios (δD values) and pollen assemblages from the annually-laminated sediment record from lake Meerfelder Maar (Germany). Over the investigated interval (3200-2000 varve years BP), terrestrial lipid biomarker δD showed a gradual trend to more negative values, consistent with the western Europe long-term climate trend of the Late Holocene. At ca. 2640 varve years BP we identified a strong increase in aquatic plants and algal remains, indicating a rapid change in the aquatic ecosystem superimposed on this long-term trend. Interestingly, this aquatic ecosystem change was accompanied by large changes in δD values of aquatic lipid biomarkers, such as nC21 and nC23 (by between 22 and 30‰). As these variations cannot solely be explained by hydroclimate changes, we suggest that these changes in the δDaq value were influenced by changes in n-alkane source organisms. Our results illustrate that if ubiquitous aquatic lipid biomarkers are derived from a limited pool of organisms, changes in lake ecology can be a driving factor for variations on sedimentary lipid δDaq values, which then could be easily misinterpreted in terms of hydroclimatic changes.

  20. Characterizing and tracing the dust sources of Lakes Sihailongwan and Huguangyan Maar in NE and SE China over the past 80 kyrs

    Science.gov (United States)

    Zaarur, Shikma; Stein, Mordechai; Mingram, Jens; Erel, Yigal

    2017-04-01

    A major challenge in the field of quaternary paleoclimate lies in reconstructing and understanding changes in atmospheric circulation and its relation to global and regional climate patterns. In this study, we use mineralogical, chemical and isotopic signatures of fine size particles in lake sediments to trace the sources of dust, as a tool to understand the synoptic patterns in East Asia during the past ˜80 kyrs. The study focuses on sediments from two maar lakes: Sihailongwan and Huguangyan in NE and SE China, respectively. These two are ideal for our study; they are hydrologically confined and do not drain any rivers or streams that introduce additional particle sources other than the volcanic rims and windblown dust. Sediment cores from both lakes were obtained by the German-Chinese drilling project (Mingram et al. 2004). Both cores have been previously dated and their general composition had been characterized (Mingram et al. 2004, Zhu et al. 2013). To characterize the local signature we additionally collected sediments from the rim and the vicinity of the lakes. Because we are interested in windblown particles, we concentrate on fine sediment fraction (material. Sr and Nd isotope ratios of materials from the lakes' rim and vicinity display large variations (87Sr/86Sr and ɛNd values of 0.7042-0.7202 and 6.0 to -8.8 for, respectively) and form two distinct mixing lines between the local basalt and two different end members. Isotopic values of core samples fall between the two lines and likely represent shifts in the relative contribution of each source.

  1. Characteristics and Environmental Significance of Magnetic Susceptibility of the Tianyang Maar Lake since Middle Pleistocene%田洋玛珥湖中更新世以来磁化率特征及其环境意义

    Institute of Scientific and Technical Information of China (English)

    杨士雄; 郑卓; 宗永强; 李杰; 黄康有

    2012-01-01

    对雷州半岛东南部的田洋玛珥湖TYC孔前40 m岩芯进行了研究,结果表明,磁化率与孢粉有很好的对应关系,因而磁化率值的高低变化能够作为该区气候环境变化的替代指标.沉积物磁化率与气候变化的关系为:磁化率的低值与气候暖湿对应;磁化率的高值则与气候寒冷或温凉相对应.中更新世以来,田洋玛珥湖气候环境演化经历了9个不同的阶段:346~301.4 kaBP,气候相对暖湿.301.4 ~248.8 kaBP,气候寒冷干燥.248.8 ~ 188.8 kaBP,气候相对暖湿.188.8~125.2 kaBP,气候寒冷干燥.125.2~69.3 kaBP,气候较为暖湿.69.3 ~ 40.43 kaBP,气候偏凉.40.43 ~25.5 kaBP,气候偏凉但较上阶段温度低,此时玛珥湖呈现出沼泽化过渡阶段.25.5~10.8 kaBP,气候寒冷干燥,玛珥湖干枯成为干玛珥湖.10.8 kaBP以来,由于后期人类活动对玛珥湖的改造,致使磁化率值不断升高.%The Tianyang Maar Lake is situated in the southeastern Leizhou Peninsula, the transitional climate zone between tropical and subtropical region of China. In this paper, a study was carried out on the upper 40 meters of core TYC collected from the Tianyang Maar Lake. The results suggest that magnetic susceptibility (MS) correlates well with pollen records. Thus, variations of MS can be used as an indicator for climate and environmental changes in the Tianyang Maar Lake. Generally, a low MS indicates a warm and humid environmental condition, while a high MS suggests a cold or cool environment. Results of the MS analysis suggest that the environmental history of the Tianyang Maar lake area since the Middle Pleistocene can be divided into 9 stages; 346 ~301.4 ka BP, the climate was relatively warm and humid. 301. 4 -248. 8 ka BP, the climate became relatively cool and dry. 248. 8 ~ 188. 8 ka BP, the climate was warm and humid. 188. 8 ~ 125. 2 ka BP, it was cold and dry. 125. 2 - 69. 3 ka BP, the climate was relatively warm and humid. 69. 3 -40. 43 ka BP

  2. Shallow-seated explosions in the construction of the Motukorea tuff ring (Auckland, New Zealand): Evidence from lithic and sedimentary characteristics

    Science.gov (United States)

    Agustín-Flores, Javier; Németh, Károly; Cronin, Shane J.; Lindsay, Jan M.; Kereszturi, Gábor

    2015-10-01

    At least 52 eruption centres are scattered within the 360 km2 Auckland Volcanic Field (AVF). Motukorea, now an island in the Waitemata Harbour, is one of 39 AVF volcanoes that experienced a phreatomagmatic explosive phase, before a magmatic phase. The volcano erupted through a 200-300 m-thick, consolidated, mudstone/sandstone sequence of the Miocene Waitemata Group, which overlies the Waipapa Terrane greywacke basement. Detailed field descriptions of the sedimentary characteristics of the early phreatomagmatic deposits were carried out, along with examination of lithics. The ejecta ring deposit comprises 55 to 60 vol.% lithics, of which Waitemata Group fragments constitute approximately 90 vol.%, whereas surges at the beginning of the eruption with progression into drier sequences upwards. This is reflected in increasing inter-bedded juvenile-pyroclast-dominated fall deposits up-sequence. These characteristics are attributed to the changing hydrogeological conditions within the diatreme and the host rocks. These findings shed light on the eruption dynamics of phreatomagmatic eruptions through consolidated rocks in the AVF and enable the depiction of a scenario of future eruptions within the field in similar substrates.

  3. Interannual and orbital-scale climate variability in the early Miocene: Compound-specific D/H records from the Foulden Maar Diatomite, New Zealand

    Science.gov (United States)

    D'Andrea, W. J.; Fox, B.; Lee, D.

    2013-12-01

    The El Niño-Southern Oscillation (ENSO) cycle is the most important interannual climate variation on Earth and has far reaching impacts on global climate. However, the behavior of ENSO over orbital timescales and under different global climate states is poorly understood and controversial. It has been proposed that ENSO behaved much differently in the past, perhaps even transitioning toward a permanent El Niño-like state. Our understanding of the ENSO response to orbital variations and the background climate state is incomplete and there are fundamental flaws in our knowledge of this important player in Earth's climate system. Here we present a 100,000-yr long compound-specific hydrogen isotope (D/H) record along with varve thickness data that document southern New Zealand (46°S, 170°E) climate in the early Miocene; the results suggest modulation of ENSO by Earth's orbital changes at precession (~22,000 year) and semiprecession (~11,000 year) timescales. Our data come from analyses of the Foulden Maar Diatomite, an annually laminated sediment sequence from an early Miocene freshwater lake in Otago, New Zealand. The diatomite contains approximately 100,000 dark-light couplets interpreted as biogenic varves, and has exquisite preservation of leaves, flowers, insects, diatom frustules and n-alkanoic acids derived from leaf waxes and algae. D/H records from n-alkanoic acids reveal large variations corresponding to precession (~22,000 yrs) and semi-precession (~11,000 yrs) timescales that reflect large paleohydrological changes. Varve thickness records reveal spectral power that exceeds the 99% confidence limit in the 3 to 7-yr band, and indicate that ENSO was an important driver of interannual climate variability in southern New Zealand during the early Miocene. We propose that the semiprecession-paced hydrologic changes represented by our compound-specific D/H record document the modulation of ENSO by variations in Earth's orbital configuration; specifically, that

  4. Geen Sedum maar kruidenrijk gras

    NARCIS (Netherlands)

    Metselaar, K.; Vrolijk, M.; Kromhout, R.

    2013-01-01

    Veel groene daken bestaan uit gemakkelijk te onderhouden Sedum-plantjes. In dit artikel uitleg over de vegetatiekeuze bij de aanleg van het experimentendak van NIOO, aangelegd in najaar 2012. Klaas Metselaar en Stef Jansen onderzoeken het gedrag van verschillende soorten begroeiing. Het dak is daart

  5. Kuidas õppida klassikutelt? / Ellu Maar

    Index Scriptorium Estoniae

    Maar, Ellu

    2007-01-01

    Anders Härmi ja Priit Raua kureeritud II NU performance'i-festival: Susanne Linke "Akuutne" (2003) ja "Im Dade Wannen" (1980) 9. XI ning Roi Vaara "Möödalöögid" 10. XI Kanuti gildi saalis. Performance'i rekonstrueerimisest

  6. Frequency of event deposits reflecting glacial/interglacial conditions during the last ca. 50,000 years in the south Patagonian maar lake Laguna Potrok Aike, Argentina

    Science.gov (United States)

    Kliem, Pierre; Hahn, Annette; Ohlendorf, Christian; Zolitschka, Bernd; Pasado Science Team

    2010-05-01

    Laguna Potrok Aike is a 100m deep maar lake located in the dry steppe of southern Patagonia. The catchment area of >200km² mainly consists of till from Bella Vista and Río Ciaike Glaciations as well as of alkali-olivine basalts of the Pali Aike Volcanic Field. Today's regional climate is affected by the Southern Hemispheric Westerlies and the rainshadow effect of the north-south striking Andean mountain chain. Since lakes are valuable terrestrial paleoclimate archives, sediments of Laguna Potrok Aike should reflect shifts of mid latitude wind and pressure fields as well as precipitation changes in southeastern South America. Aiming at the reconstruction of past climate, the deep drilling at Laguna Potrok Aike was accomplished in the framework of the ICDP project PASADO during Sept. to Dec. 2008. By correlation of three holes drilled at Site 2 ca. 700 m south of the lake's center, a composite profile of 106.09 mcd (meters composite depth) was established. According to the lowermost 14C-age of aquatic macro remains from 80.6 mcd, the entire record comprises at least 50,000 years. The initial lithological description indicates that 50.74 m (i.e. 47.8%) of the sediment record consists of remobilized sediment (turbidity currents; homogenites; ball and pillow structures, gravel layers, slumps). Such deposits are almost absent in the top 12 mcd, where laminated clays and silts dominate. Correlation with an existing piston core allows a temporal relation to the Holocene. Apart from obviously remobilized deposits Holocene sediments are distinguished from Late Glacial deposits by a lower frequency of coarse silt/fine sand layers within a silt/clay matrix. Frequency and thickness of remobilized deposits increase with sediment depth. Most reworked sections are composed of three units: (1) a dark, coarse and fining upward base overlain by (2) a homogeneous layer of silt and (3) clay capped by a relatively thin light colored clay layer. Such sequences were often described as

  7. 湛江湖光岩玛珥湖全新世粒度变化特征及古气候意义%Grain size variation and its environmental significance from Huguangyan Maar Lake, Zhanjiang since the Holocene

    Institute of Scientific and Technical Information of China (English)

    吴旭东; 刘国旭; 沈吉

    2016-01-01

    Through investigation on grain size parameters, loss on ignition ( 550℃) and Ti contents of Huguangyan Maar Lake sed-iment during the Holocene, frequency curve of grain size suggests that terrestrial input of Huguangyan Maar Lake are predominantly from its small catchment, and grain size variation of the sediment during the Holocene was determined by precipitation instead of lake level fluctuation, with coarser grain size indicating higher precipitation and finer grain size indicating lower precipitation. Asian monsoon at Zhanjiang area was strong in the early Holocene, and weakened substantially since 6085 a B.P.. The substantial weake-ning of Asian monsoon in the mid-Holocene recorded by Huguangyan Maar Lake sediment occurred at the time which was very close to the time of substantially weakened monsoon event recorded by many other archives around the globe, embodying globalization of monsoon evolution during the Holocene of Zhanjiang area. Weakened Asian monsoon and enhanced drought since 6085 a B. P. might be related to the enhanced ENSO activity. The amplitude of grain size parameters, loss on ignition ( 550℃) and Ti content increased remarkably after 2000 a B.P., which may be due to intensified human activity and it is the result of both human activities and climate change.%对湖光岩玛珥湖沉积物全新世粒度参数、550℃烧失量和Ti元素含量的变化特征研究后认为:粒度频率特征曲线指示湖光岩玛珥湖沉积物的外源输入部分主要来自其小流域;沉积物粒径的变化主要受降雨量,而不是湖泊水位波动的控制;较粗的粒径指示降雨量增加,较细的粒径指示降雨量降低.湛江地区全新世早期季风强盛,6085 a B.P.以后,季风显著减弱.湖光岩沉积物记录的全新世中期季风迅速减弱的发生时间与全球很多地质载体记录的全新世中期季风迅速减弱时间都非常接近,体现了湛江地区全新世季风演化的全球性.

  8. 离子色谱法同时测定湖光岩玛珥湖水中5种阴离子%Simultaneous Determination of Five Kinds of Anions in Huguangyan Maar Lake Water by Ion Chromatography

    Institute of Scientific and Technical Information of China (English)

    张兆霞; 李泳

    2016-01-01

    Simultaneous determination of five kinds of anions in Huguangyan Maar Lake water by ion chro-matography was established in this paper.Water samples were filtered by 0.22 μm microporous membrane fil-ter,then five kinds of anions including F- ,Cl- ,NO-2 ,NO-3 ,and SO2 -4 in Huguangyan Maar Lake water were determined quickly and accurately with 1.8 mmol·L-1 Na2 CO3-1.7 mmol·L-1 NaHCO3 mixed solution as a mobile phase,and the flow rate was 1.0 mL·min-1 .Detection results had wide linear range and good linear correlation(R =0.9990 ~0.9995 ),the relative standard deviation(RSD)was below 5%,the average recovery rate was 95.2%~106.5%,and the minimum detection limit was 0.01 ~0.28 μg·mL-1 .This method is sim-ple,rapid,accurate and reliable,and it can be used for simultaneous determination of anions in water.%建立了一种同时测定湖光岩玛珥湖水中5种阴离子的离子色谱分析法。水样经0.22μm 微孔滤膜过滤后直接进样,以1.8 mmol·L-1碳酸钠-1.7 mmol·L-1碳酸氢钠混合溶液为流动相,流速为1.0 mL·min-1,快速准确地同时测定湖光岩玛珥湖水中 F-、Cl-、NO-2、NO-3、SO2-4等5种阴离子。检测结果线性范围广,线性相关性好(R=0.9990~0.9995),相对标准偏差(RSD)均低于5%,平均加标回收率为95.2%~106.5%,最低检测限为0.01~0.28μg·mL-1。该法简便、快速、准确、可靠,可用于水中阴离子的同时测定。

  9. Testing the sensitivity of stable carbon isotopes of sub-fossil Sphagnum cellulose to past climate variability: a two millennia high resolution stable carbon isotope time series from the peat deposit "Dürres Maar", Germany

    Science.gov (United States)

    Moschen, Robert; Kühl, Norbert; Peters, Sabrina; Vos, Heinz; Lücke, Andreas

    2010-05-01

    Peat deposits are terrestrial archives of environmental changes and climate dynamics over time. They are widely distributed and cover a large part of the earth's land surface often within human habitat and, thus, form an excellent basis for evaluating ecosystem and climate dynamics by multiple geochemical and biological methods. Records of the stable carbon composition of cellulose separately extracted from selected Sphagnum plant components (δ13CSphagnum) from the kettle-hole type peat deposit of 'Dürres Maar' are presented. Manually separated Sphagnum stems, branches and the small leaves covering Sphagnum branches were used for cellulose extraction and subsequent isotope measurements, because intra-plant δ13CSphagnum variability between different physical components of individual modern plants has been described (Loader et al. 2007). We observed the same isotopic offset between single plant components of sub-fossil Sphagnum plant components which is statistically highly significant and observable down-core (Moschen et al. 2009). Using the size fraction of 355-630 μm, which almost exclusively consists of single Sphagnum leaves, allows to derive environmental and climate signals based on a plant response to external controls, presumably including temperature and relative humidity. Because down-core changes in the ratio of different plant components in the peat profile seem probable, erroneous interpretations of isotope records are likely if no differentiation into single Sphagnum plant components is possible. A high resolution time series of δ13CSphagnum is presented covering the last two millennia, tracing decadal to sub-decadal past environmental and climate dynamics. The thickness of the water film surrounding the chloroplasts of Sphagnum plants has been suggested as the most important factor influencing δ13CSphagnum. This points to bog surface wetness which is primarily driven by precipitation and evaporation temperature as the major control of δ13

  10. 40Ar/ 39Ar and 14C geochronology of the Albano maar deposits: Implications for defining the age and eruptive style of the most recent explosive activity at Colli Albani Volcanic District, Central Italy

    Science.gov (United States)

    Giaccio, B.; Marra, F.; Hajdas, I.; Karner, D. B.; Renne, P. R.; Sposato, A.

    2009-09-01

    New 40Ar/ 39Ar and 14C ages have been found for the Albano multiple maar pyroclastic units and underlying paleosols to document the most recent explosive activity in the Colli Albani Volcanic District (CAVD) near Rome, Italy, consisting of seven eruptions (Albano 1 = oldest). Both dating methodologies have been applied on several proximal units and on four mid-distal fall/surge deposits, the latter correlated, according to two current different views, to either the Albano or the Campi di Annibale hydromagmatic center. The 40Ar/ 39Ar ages on leucite phenocrysts from the mid-distal units yielded ages of ca. 72 ka, 73 ka, 41 ka and 36 ka BP, which are indistinguishable from the previously determined 40Ar/ 39Ar ages of the proximal Albano units 1, 2, 5 and 7, thus confirming their stratigraphic correspondence. Twenty-one 14C ages of the paleosols beneath Albano units 3, 5, 6 and 7 were found for samples collected from 13 proximal and distal sections, some of which were the same sections sampled for 40Ar/ 39Ar measurements. The 14C ages were found to be stratigraphically inconsistent and highly scattered, and were systematically younger than the 40Ar/ 39Ar ages, ranging from 35 ka to 3 ka. Considering the significant consistence of the 40Ar/ 39Ar chronological framework, we interpret the scattered and contradictory 14C ages to be the result of a variable contamination of the paleosols by younger organic carbon deriving from the superficial soil horizons. These results suggest that multiple isotopic systems anchored to a robust stratigraphic framework may need to be employed to determine accurately the geochronology of the CAVD as well as other volcanic districts.

  11. A Compilation of Gas Emission-Rate Data from Volcanoes of Cook Inlet (Spurr, Crater Peak, Redoubt, Iliamna, and Augustine) and Alaska Peninsula (Douglas, Fourpeaked, Griggs, Mageik, Martin, Peulik, Ukinrek Maars, and Veniaminof), Alaska, from 1995-2006

    Science.gov (United States)

    Doukas, Michael P.; McGee, Kenneth A.

    2007-01-01

    INTRODUCTION This report presents gas emission rates from data collected during numerous airborne plume-measurement flights at Alaskan volcanoes since 1995. These flights began in about 1990 as means to establish baseline values of volcanic gas emissions during periods of quiescence and to identify anomalous levels of degassing that might signal the beginning of unrest. The primary goal was to make systematic measurements at the major volcanic centers around the Cook Inlet on at least an annual basis, and more frequently during periods of unrest and eruption. A secondary goal was to measure emissions at selected volcanoes on the Alaska Peninsula. While the goals were not necessarily met in all cases due to weather, funding, or the availability of suitable aircraft, a rich dataset of quality measurements is the legacy of this continuing effort. An earlier report (Doukas, 1995) presented data for the period from 1990 through 1994 and the current report provides data through 2006. This report contains all of the available measurements for SO2, CO2, and H2S emission rates in Alaska determined by the U. S. Geological Survey from 1995 through 2006; airborne measurements for H2S began in Alaska in 2001. The results presented here are from Cook Inlet volcanoes at Spurr, Crater Peak, Redoubt, Iliamna, and Augustine and cover periods of unrest at Iliamna (1996) and Spurr (2004-2006) as well as the 2006 eruption of Augustine. Additional sporadic measurements at volcanoes on the Alaska Peninsula (Douglas, Martin, Mageik, Griggs, Veniaminof, Ukinrek Maars, Peulik, and Fourpeaked during its 2006 unrest) are also reported here.

  12. Continuous monitoring of diffuse CO2 degassing at Taal volcano, Philippines

    Science.gov (United States)

    Padron, E.; Hernandez Perez, P. A.; Arcilla, C. A.; Lagmay, A. M. A.; Perez, N. M.; Quina, G.; Padilla, G.; Barrancos, J.; Cótchico, M. A.; Melián, G.

    2016-12-01

    Observing changes in the composition and discharge rates of volcanic gases is an important part of volcanic monitoring programs, because some gases released by progressive depressurization of magma during ascent are highly mobile and reach the surface well before their parental magma. Among volcanic gases, CO2 is widely used in volcano studies and monitoring because it is one of the earliest released gas species from ascending magma, and it is considered conservative. Taal Volcano in Southwest Luzon, Philippines, lies between a volcanic arc front (facing the subduction zone along the Manila Trench) and a volcanic field formed from extension beyond the arc front. Taal Volcano Island is formed by a main tuff cone surrounded by several smaller tuff cones, tuff rings and scoria cones. This island is located in the center of the 30 km wide Taal Caldera, now filled by Taal Lake. To monitor the volcanic activity of Taal volcano is a priority task in the Philippines, because several million people live within a 20-km radius of Taal's caldera rim. In the period from 2010-2011, during a period of volcanic unrest, the main crater lake of Taal volcano released the highest diffuse CO2 emission rates reported to date by volcanic lakes worldwide. The maximum CO2 emission rate measured in the study period occurred two months before the strongest seismic activity recorded during the unrest period (Arpa et al., 2013, Bull Volcanol 75:747). In the light of the excellent results obtained through diffuse degassing studies, an automatic geochemical station to monitor in a continuous mode the diffuse CO2 degassing in a selected location of Taal, was installed in January 2016 to improve the early warning system at the volcano. The station is located at Daang Kastila, at the northern portion of the main crater rim. It measures hourly the diffuse CO2 efflux, atmospheric CO2 concentration, soil water content and temperature, wind speed and direction, air temperature and humidity, rainfall

  13. Geochemical monitoring of Taal volcano (Philippines) by means of diffuse CO2 degassing studies

    Science.gov (United States)

    Padrón, Eleazar; Hernández, Pedro A.; Arcilla, Carlo; Pérez, Nemesio M.; Lagmay, Alfredo M.; Rodríguez, Fátima; Quina, Gerald; Alonso, Mar; Padilla, Germán D.; Aurelio, Mario A.

    2017-04-01

    Observing changes in the discharge rate of CO2 is an important part of volcanic monitoring programs, because it is released by progressive depressurization of magma during ascent and reach the surface well before their parental magma. Taal Volcano in Southwest Luzon, Philippines, lies between a volcanic arc front facing the subduction zone along the Manila Trench and a volcanic field formed from extension beyond the arc front. Taal Volcano Island is formed by a main tuff cone surrounded by several smaller tuff cones, tuff rings and scoria cones. This island is located in the center of the 30 km wide Taal Caldera, now filled by Taal Lake. To monitor the volcanic activity of Taal volcano is a priority task in the Philippines, because several million people live within a 20-km radius of Taal's caldera rim. During the last period of volcanic unrest from 2010 to 2011, the main crater lake of Taal volcano released the highest diffuse CO2 emission rates through the water surface reported to date by volcanic lakes worldwide. The maximum CO2 emission rate measured in the study period occurred two months before the strongest seismic activity recorded during the unrest period (Arpa et al., 2013, Bull Volcanol 75:747). After the unrest period, diffuse CO2 emission has remained in the range 532-860 t/d in the period 2013-2016. In January 2016, an automatic geochemical station to monitor in a continuous mode the diffuse CO2 degassing in a selected location of Taal, was installed in January 2016 to improve the early warning system at the volcano. The station is located at Daang Kastila, at the northern portion of the main crater rim. It measures hourly the diffuse CO2 efflux, atmospheric CO2 concentration, soil water content and temperature, wind speed and direction, air temperature and humidity, rainfall, and barometric pressure. The 2016 time series show CO2 efflux values in the range 20-690 g m-2 d-1.Soil temperature, heavily influenced by rainfall, ranged between 74 and 96o

  14. Uptake of dissolved nitrogen by phytoplankton in spring in Huguangyan Maar Lake%湖光岩玛珥湖春季浮游植物对溶解态氮的吸收∗

    Institute of Scientific and Technical Information of China (English)

    张国维; 李长玲; 黄翔鹄; 古滨河

    2015-01-01

    利用15 N稳定同位素示踪技术,采用现场挂瓶培养的方法测定了湖光岩玛珥湖浮游植物群落对铵态氮、硝态氮和尿素态氮的吸收速率,研究了湖光岩玛珥湖浮游植物群落氮吸收及其吸收动力学特征.结果表明:湖光岩玛珥湖共检测到浮游植物7门54种(包括变种和变型),主要为蓝藻门、硅藻门和绿藻门种类,分别占浮游植物总量的44.68%、26.70%和19.21%,其中水华微囊藻(Microcystis flos-aquae)与铜绿微囊藻(Microcystis aeruginosa)为绝对优势种,优势度分别为0.39与0.28.湖光岩玛珥湖浮游植物群落对铵态氮的绝对吸收速率最高,分别是对硝态氮、尿素态氮绝对吸收速率的5.8和4.2倍,占3种溶解态氮总吸收量的73.3%.铵态氮、硝态氮和尿素态氮的相对优先指数分别为2.907、0.190和1.192,说明浮游植物群落优先吸收铵态氮,其次为尿素态氮,最后为硝态氮.铵态氮、硝态氮和尿素态氮的周转时间分别为3.72、57.03和9.07 h.湖光岩玛珥湖浮游植物对溶解态氮的吸收可用Michaelis-Menten酶动力学方程描述,最大比吸收速率表现为铵态氮>尿素态氮>硝态氮,亲和力表现为硝态氮>铵态氮>尿素态氮.湖光岩玛珥湖浮游植物群落对铵态氮具有较高的吸收潜力,并且对硝态氮具有一定的亲和力,具备利用硝态氮的能力.%Using 15 N stable isotope tracer technique by adopting the in-situ flask culture, the uptake rates of ammonium, nitrate and urea by phytoplankton community were measured in Huguangyan Maar Lake, in order to characterize the nitrogen absorption and the characteristics of absorption kinetics by phytoplankton community in spring in the lake. The results showed that there were 54 species ( including varieties and forms belonging to 7 phyla) of phytoplankton in the lake, mainly from the Cyanophyta, Bacilla-riophyta and Chlorophyta, which accounted for 44. 68%, 26. 70% and 19. 21%, respectively

  15. Foliumzuursuppletiebeleid bij zwangerschap werkt, maar moet beter

    NARCIS (Netherlands)

    de Smid, Denhard J; de Jong-van den Berg, Lolkje T W; Cornel, Martina C

    2012-01-01

    The correct usage of folic acid (FA) supplements to prevent neural tube defects (NTDs) increased from 28% in 1996 to 50% in 2005 and remained stable until 2009. Recent data from national birth defect registries show a decrease of NTD prevalence from 13.2 (per 10,000) in 1997 to 8.3 in 2005 and stabi

  16. Rajangu, omandireform ja inimkehad / Ellu Maar

    Index Scriptorium Estoniae

    Maar, Ellu

    2007-01-01

    Raul Rajangu näitus "Kuldne kodu. Muldne kodu" Vaal galeriis. Sepakunsti, ehtekunsti ning skulptuuri õppivate tudengite (juhendajad Anu Juurak, Jüri Ojaver) ja Raoul Kurvitza näitus "Luik, haug ja vähk" Kunstihoone galeriis. Eesti Maalikunstnike Liidu näitus "Keha muutumine" ArtDepo Galeriis, kuraator Ado Lill. Loetletud osavõtjaid

  17. Field-mapping and petrographic analysis of volcanoes surrounding the Lake Natron Homo sapiens footprint site, northern Tanzania

    Science.gov (United States)

    Hewitt, S. M.; Zimmer, B.; Liutkus, C.; Carmichael, S. K.; McGinnis, K.

    2010-12-01

    The Lake Natron Homo sapiens footprint site is located in northern Tanzania along the East African Rift escarpment. The site is positioned south of Lake Natron within an ephemeral channel of the Engare Sero River. The hominid footprints are preserved in a tuff, which originated from one of the volcanic centers surrounding the site. Two large volcanoes in the surrounding region, including the active carbonatite producing Oldoinyo L’engai and the now extinct Kerimasi are possible sources. This area also contains over 30 smaller tuff cones and tuff rings that have been poorly mapped and not analyzed in detail. The site is significant as it is the oldest modern human trackway in East Africa and one of the largest collections of hominid footprints in the world. Determining the source of the footprinted volcanic ash requires detailed field mapping, and both petrographic and geochemical analyses. Extensive field-mapping of the region revealed multiple regional beds that stratigraphically overlay the footprinted layer. Age dating as well as geochemical analysis is being conducted to relate these beds to the footprinted layer. Field-mapping showed that the footprinted tuff is over 35 cm thick, suggesting a large, sustained eruption. The bulk of the tuff cones examined in the field visibly varied in composition to the footprinted tuff and, based on proximity to the footprint site, are too small to produce the requisite volume of ash. Field analysis of samples collected from Oldoinyo L’engai reveal the most similar mineral assemblages to the footprinted layer, and the large volcano provides a source substantial enough to create a thick ash bed 10 km north of the summit. Preliminary research reveals that the footprinted tuff is a phonolite, characterized by silica depletion and the presence of sanidine, augite, and annite with interstitial calcite. XRD analysis of samples collected from Oldoinyo L’engai reveal a nepheline-rich phonolite with zeolites (ie. phillipsite

  18. Spatial analysis of the Los Tuxtlas Volcanic Field (LTVF) and hazard implications

    Science.gov (United States)

    Sieron, K.; Alvarez, D.

    2013-05-01

    The Tuxtlas volcanic field (LTVF) is located in the southern part of Veracruz state (Mexico) adjacent to the Gulf of Mexico and consists of 4 large volcanic edifices, 3 of them considered inactive and the active San Martin shield volcano. The monogenetic volcanoes belonging to the younger series are represented by hundreds of scoria cones and tens of maars and tuff cones, all of which show ages less than 50,000 years. In comparison to other monogenetic fields, the scoria cone density is quite elevated with 0.2 cones/km2, although the highest scoria cone density can be observed along narrow zones corresponding to the main NW-SE fault system where it reaches 0.7 cones/km2. Scoria cones occur as single edifices and in clusters and show individual edifice volumes of 0.0009 km3 to 0.2 km3, cone heights varying between 21.39 m and 299.21 m. Lava flows associated to scoria cones originate especially along the main NW-SE trending main fault and present run out distances up to 11 kilometers. Only few radiocarbon and Ar-Ar dates exist for the LTVF, mostly because of the high cone density and dense vegetation of the Los Tuxtlas region. Therefore, morphological parameters were used to estimate relative ages. In consequence, the scoria cones can be subdivided into four age groups; the members of each group do not seem to follow any particular trend and are rather scattered throughout the field. The explosive (or wet) equivalents of the mainly basaltic strombolian scoria cones are explosion craters, such as maars and tuff cones, show the highest concentration along the border of the two main geological units to the S of the area with the highest scoria cone concentration. Although the relatively small scale strombolian eruptions associated to scoria cone emplacement do not represent a considerable hazard for the surrounding population, lava flows can easily extent to the main urban zones accommodating about 262,384 inhabitants. Within the area prone to maar formation, the hazard

  19. 玛珥湖好氧不产氧光合细菌pufM基因DNA和mRNA的定量及多样性分析%Genetic diversity and quantification of aerobic anoxygenic phototrophic bacteria in Hugangyan Maar Lake based on pufM DNA and mRNA analysis

    Institute of Scientific and Technical Information of China (English)

    陈晓洁; 曾永辉; 简纪常; 鲁义善; 吴灶和

    2012-01-01

    [Objective] Maar lake is a special type of Crater Lake.Huguangyan Maar Lake was formed about 140 k-160 k years ago, fully closed, and has not yet been affected by human activities, where abundant and novel microbial species might dwell as reported previously.Aerobic anoxygenic phototrophic bacteria (AAPB) is a functional bacterial group with long evolution history in Earth possessing unique physiological and ecological characteristics.To date, our knowledge about AAPB distribution in Maar Lake is still blank.[Methods] Here, by constructing and analyzing six clone libraries of the photosynthetic reaction center pufM gene from total DNA and RNA, respectively, with 1 m, 5 m, and 12 m water layers in Huguangyan Maar Lake, and combining quantitative Real-time PCR, we studied AAPB's distribution, phy-logenetic diversity and the proportion in the total bacteria in different water layers.The results of coverage value and rarefaction curves of six libraries showed that AAPB diversity was sampled well for the purpose of revealing the diversity of main AAPB groups in each water layer.[Results] BLAST analysis showed that pufM sequences in Maar Lake were 80%-93% similar to public sequences.Diversity index indicated that the AAPB diversity in surface and deep layers was similar, whereas diversity in the intermediate layer was lowest.In view of total RNA and DNA data, pufM RNA diversity was higher than that of DNA.Phylogenetic and statistical analysis revealed that 49.43% sequences are fell into the OTUs 21-24 which were closely related to P-proteobacteria and represent dominated AAPB groups.Quantitative PCR results showed that the percentage of AAPB in total bacteria in 1 m water layer reached a highest value of 38.06%, whereas only 0.85% and 9.54% in 5 m and 12 m, respectively.[Conclusion] Huguangyan Maar Lake is occupied by rich and diverse AAPB groups.%[目的]湖光岩玛珥湖是一类特殊的火山口湖,它完全封闭,地质年代久远,尚未受人类活动的剧烈

  20. Volcanism-sedimentation interaction in the Campo de Calatrava Volcanic Field (Spain): a magnetostratigraphic and geochronological study

    Science.gov (United States)

    Herrero-Hernández, Antonio; López-Moro, Francisco Javier; Gallardo-Millán, José Luis; Martín-Serrano, Ángel; Gómez-Fernández, Fernando

    2015-01-01

    This work focuses on the influence of Cenozoic volcanism of the Campo de Calatrava volcanic field on the sedimentation of two small continental basins in Spain (Argamasilla and Calzada-Moral basins). The volcanism in this area was mainly monogenetic, according to the small-volume volcanic edifices of scoria cones that were generated and the occurrence of tuff rings and maars. A sedimentological analysis of the volcaniclastic deposits led to the identification of facies close to the vents, low-density (dilute) pyroclastic surges, secondary volcanic deposits and typical maar deposits. Whole-rock K/Ar dating, together with palaeomagnetic constraints, yielded an age of 3.11-3.22 Ma for the onset of maar formation, the deposition finished in the Late Gauss-Early Matuyana. Using both techniques and previous paleontological data allowed it to be inferred that the maar formation and the re-sedimentation stage that occurred in Argamasilla and Calzada-Moral basins were roughly coeval. The occurrence of syn-eruption volcaniclastic deposits with small thicknesses that were separated by longer inter-eruption periods, where fluvial and lacustrine sedimentation was prevalent, together with the presence of small-volume volcanic edifices indicated that there were short periods of volcanic activity in this area. The volcanic activity was strongly controlled by previous basement faults that favoured magma feeding, and the faults also controlled the location of volcanoes themselves. The occurrence of the volcanoes in the continental basins led to the creation of shallow lakes that were related to the maar formation and the modification of sedimentological intra-basinal features, specifically, valley slope and sediment load.

  1. The Holocene Climate Linkage between Low Latitude Area and North Atlantic:Case study on element and element ratios of Huguangyan Maar lake%全新世低纬地区古环境演化与北大西洋之间的联系——以湖光岩玛珥湖元素和元素比值记录为例

    Institute of Scientific and Technical Information of China (English)

    吴旭东; 沈吉; 汪勇

    2011-01-01

    Future environment evolution is a great composition of global change research.High resolution paleoenvironment study can help us to understand the rules of past global change and provides scientific basis for forecasting future environment evolution.As a special type of crater lake,maar lake has unique advantages in forming and conserving high resolution geological record.Elementary assemblages of the lake sediment are not only affected by depositional environment,but also linked to geochemical property of the element.There is not straightforward connection between most of the elements and the environment variation due to the complexity of depositional environment and various changes after deposition.The combination of element and element ratios can magnify the response to climate change,thus weaken the effect of disturbing factors.The Huguangyan maar lake(21°9′N,110°17′E) is located 18 km southwest of Zhanjiang City,Guangdong province.In November,2009,we sampled two parallel long cores using UWITEC platform and a piston corer in the western part of the Huguangyan maar lake where the water depth is 16.2m(N 21°08′38.28″,E 110°16′45.66″).The drill core for this study is 855 cm long.The core was split along the axle wire before elementary analysis,elementary analysis is carried by X-ray fluorescence spectrometer at State Key Laboratory of Marine Geology of Tongji University,the measuring space is 1 cm.Age model is obtained through comparison with previous study.Fe/Mn ratios,Rb/Sr ratios,Sr intensities and 550℃ loss on ignition(LOI) are good indicators of environmental change: Fe/Mn ratios can reflect water depth variation due to different sensibilities toward oxido-reduction condition,Rb/Sr ratios can reflect weathering intensity within the drainage basin,550℃ loss on ignition(LOI) is an indicator of lake productivity,thus reflect the climate indirectly.Through high resolution investigation of above indicators,we reconstructed

  2. Hydrovolcanism: Basic considerations and review

    Science.gov (United States)

    Sheridan, Michael F.; Wohletz, Kenneth H.

    1983-09-01

    Hydrovolcanism refers to natural phenomena produced by the interaction of magma or magmatic heat with an external source of water, such as a surface body or an aquifer. Hydroexplosions range from relatively small single events to devastating explosive eruptive sequences. Fuel-coolant interaction (FCI) serves as a model for understanding similar natural explosive processes. This phenomena occurs with magmas of all compositions. Experiments have determined that the optimal mass mixing ratio of water to basaltic melt for efficient conversion of thermal energy into mechanical energy is in the range of 0.1 to 0.3. For experiments near this optimum mixture, the grain-size of explosion products is always fine (less than 50 μm). The particles generated are much larger (greater than 1-10 mm) for explosions at relatively low or high ratios. Both natural and experimental pyroclasts produced by hydroexplosions have characteristic morphologies and surface textures. SEM micrographs show that blocky, equant grain shapes dominate. Glassy clasts formed from fluid magma have low vesicularity, thick bubble walls, and drop-like form. Microcystalline essential clasts result from chilling of magma during or shortly following explosive mixing. Crystals commonly exhibit perfect faces with patches of adhering glass or large cleavage surfaces. Edge modification and rounding of pyroclasts is slight to moderate. Grain surface alteration (pitting and secondary mineral overgrowths) are a function of the initial water to melt ratio as well as age. Deposits are typically fine-grained and moderately sorted, having distinctive size distributions compared with those of fall and flow origin. Hydrovolcanic processes occur at volcanoes of all sizes ranging from small phreatic craters to huge calderas. The most common hydrovolcanic edifice is either a tuff ring or a tuff cone, depending on whether the surges were dry (superheated steam media) or wet (condensing steam media). Hydrovolcanic products are

  3. Volcanic sulfur dioxide index and volcanic explosivity index inferred from eruptive volume of volcanoes in Jeju Island, Korea: application to volcanic hazard mitigation

    Science.gov (United States)

    Ko, Bokyun; Yun, Sung-Hyo

    2016-04-01

    Jeju Island located in the southwestern part of Korea Peninsula is a volcanic island composed of lavaflows, pyroclasts, and around 450 monogenetic volcanoes. The volcanic activity of the island commenced with phreatomagmatic eruptions under subaqueous condition ca. 1.8-2.0 Ma and lasted until ca. 1,000 year BP. For evaluating volcanic activity of the most recently erupted volcanoes with reported age, volcanic explosivity index (VEI) and volcanic sulfur dioxide index (VSI) of three volcanoes (Ilchulbong tuff cone, Songaksan tuff ring, and Biyangdo scoria cone) are inferred from their eruptive volumes. The quantity of eruptive materials such as tuff, lavaflow, scoria, and so on, is calculated using a model developed in Auckland Volcanic Field which has similar volcanic setting to the island. The eruptive volumes of them are 11,911,534 m3, 24,987,557 m3, and 9,652,025 m3, which correspond to VEI of 3, 3, and 2, respectively. According to the correlation between VEI and VSI, the average quantity of SO2 emission during an eruption with VEI of 3 is 2-8 × 103 kiloton considering that the island was formed under intraplate tectonic setting. Jeju Island was regarded as an extinct volcano, however, several studies have recently reported some volcanic eruption ages within 10,000 year BP owing to the development in age dating technique. Thus, the island is a dormant volcano potentially implying high probability to erupt again in the future. The volcanoes might have explosive eruptions (vulcanian to plinian) with the possibility that SO2 emitted by the eruption reaches stratosphere causing climate change due to backscattering incoming solar radiation, increase in cloud reflectivity, etc. Consequently, recommencement of volcanic eruption in the island is able to result in serious volcanic hazard and this study provides fundamental and important data for volcanic hazard mitigation of East Asia as well as the island. ACKNOWLEDGMENTS: This research was supported by a grant [MPSS

  4. Voldemar Miller ja kodu-uurimisliikumine / Eva Maaring

    Index Scriptorium Estoniae

    Maaring, Eva

    2011-01-01

    Eesti NSV Teaduste Akadeemia kodu-uurimise komisjoni liikmeks kinnitati Voldemar Miller 1961. aastal. Ta oli Tallinna Linnamuuseumi kodu-uurimisringi asutaja (1963) ja juht. Voldemar Millerist kui kodu-uurimistöö juhendajast, õpetajast ja mõtestajast

  5. De voorspellende overheid : Transparantie is noodzakelijk, maar hoe?

    NARCIS (Netherlands)

    Leenes, Ronald

    2016-01-01

    Public administrations have always dealt with large volumes of data. They are now increasingly adopting sophisticated big data technologies to further leverage the data. Data provided by citizens, observed by sensors, deduced and inferred from diverse data sets are being used for decision making and

  6. Hans Kruusi seotusest kodu-uurimisliikumisega / Eva Maaring

    Index Scriptorium Estoniae

    Maaring, Eva

    2011-01-01

    Uks kodu-uurimise valdkonda paotus Hans Kruusile Tartu Õpetajate Seminaris õppides 1910. aastal. 1920. aastatel elavnes Tartus teaduslik kodu-uurimine, hakkasid ilmuma koguteosed. Ajaloolasena oli nendes oma osa H. Kruusil. 1958. aastal sai Hans Kruusist Eesti NSV TA juures tegutseva kodu-uurimise komisjoni esimees. Hans Kruusi tabavaid ütlusi

  7. Maar hier gaat alles gewoon verder.’

    Directory of Open Access Journals (Sweden)

    Hilde van Belle

    2015-05-01

    Full Text Available But here everything keeps going on. Lieve Joris’ journalistic ethos in De poorten van Damascus In her book De poorten van Damascus (Damascus’ gates (1993, Lieve Joris reports on her longtime stay in the early nineties with an old friend in Damascus. As a literary journalist, Joris diverges from the conventional reporting style that follows strict rules in order to ensure an objectivity effect, and chooses a narrative form that allows for more personal interaction between journalist and source. Since this narrative form is widely used in fiction, Joris runs the risk of losing her ethos as a journalist. I will examine in what ways Joris negotiates this ethos, and how she manages to bring the risks of her personal and empathic style of journalism to the fore. This analysis draws from the rhetorical perspective introduced by Ruth Amossy, and particularly its focus on ethos both in media and literary discourse.

  8. Pestalozzi was een verdienstelijk didacticus maar slecht organisator

    NARCIS (Netherlands)

    Jong, Barbara de

    1996-01-01

    Johann Heinrich Pestalozzi (1746-1827) behoort volgens de traditie in het rijtje klassieke ‘grote pedagogen’. Pestalozzi, de onruststoker, kindervriend en failliet verklaarde weeshuisdirecteur. Pestalozzi, de didacticus die in de vorige eeuw van grote invloed is geweest op de Nederlandse kweekschole

  9. Pijnregistratie niet voor Inspectie maar voor patiënt

    NARCIS (Netherlands)

    van Boekel, Rianne L M; Steegers, Monique A H; de Blok, Carolien; Schilp, Janneke

    2014-01-01

    Increasing attention is currently being directed to the measurement and treatment of pain. A recent study concluded that the implementation of a patient safety programme was successful because 99% of the hospitals indicated that they measure postoperative pain. However, another recent study, evaluat

  10. Van eerste overheid naar eerst de burger, maar hoe?

    NARCIS (Netherlands)

    Kleistra, Yvonne; Walraven, Guido

    2014-01-01

    The first report (2013) by the Association of Netherlands Municipalities think tank deals with the question of how local governments can improve their own performance regarding the current trend of social initiatives in which citizens organize themselves to tackle problems in their neighborhoods.

  11. Van eerste overheid naar eerst de burger, maar hoe?

    NARCIS (Netherlands)

    Kleistra, Yvonne; Walraven, Guido

    2014-01-01

    The first report (2013) by the Association of Netherlands Municipalities think tank deals with the question of how local governments can improve their own performance regarding the current trend of social initiatives in which citizens organize themselves to tackle problems in their neighborhoods. Kl

  12. Pestalozzi was een verdienstelijk didacticus maar slecht organisator

    OpenAIRE

    Jong, Barbara de

    1996-01-01

    Johann Heinrich Pestalozzi (1746-1827) behoort volgens de traditie in het rijtje klassieke ‘grote pedagogen’. Pestalozzi, de onruststoker, kindervriend en failliet verklaarde weeshuisdirecteur. Pestalozzi, de didacticus die in de vorige eeuw van grote invloed is geweest op de Nederlandse kweekscholen. In 1996 wordt zijn 250ste geboortedag gevierd.

  13. Kernicterus is vermijdbaar, maar komt nog steeds voor

    NARCIS (Netherlands)

    Bousema, Sara; Govaert, Paul; Dudink, Jeroen; Steegers, Eric A P; Reiss, Irwin K M; de Jonge, Rogier C J

    2015-01-01

    Kernicterus is a severe neurological condition, caused by bilirubin-induced damage in the basal ganglia. The neurological outcome is often poor. In the past decades there seems to have been an increase in the number of reported cases of kernicterus. In order to raise awareness of this condition, we

  14. Late Holocene Human Activity Inferred from Sedimentary n-Alkanes and Their Carbon Isotope in the Huguangyan Maar Lake%湖光岩玛珥湖晚全新世人类活动的叶蜡烷烃及其碳同位素沉积记录

    Institute of Scientific and Technical Information of China (English)

    柏杨; 欧阳婷萍; 贾国东

    2014-01-01

    通过对广东省湛江市湖光岩玛珥湖晚全新世沉积物中叶蜡烷烃(n-C29,n-C31,n-C33)及其碳同位素(δ13C)进行分析,探讨该湖区约3.5 ka BP以来的植被变化历史,重点讨论了人类活动对该区域植被变化可能带来的影响。叶蜡烷烃δ13C在1.7 ka BP以前偏轻,例如长链烷烃碳同位素在1.78 ka BP为-33.27‰,表明湖区C3植物占绝对优势,表现为典型的C3型生态系统;在1.7 ka BP之后碳同位素明显快速偏重,在1.63 ka BP为-28.26‰,指示了C4植物出现和C4比例上升的过程。C4植物的出现通常指示气候的干旱化,但是烷烃Paq和ACL指数(平均链长)则显示湖区气候可能在1.7 ka BP后变湿润。通过与研究区甘蔗的同位素和ACL指数的比较分析,推测这一矛盾现象可能与湖区开始有一定规模的甘蔗种植活动有关。%In this study, late Holocene sedimentary records of leaf wax n-alkanes and theirδ13 C from Huguangyan Maar Lake (H.M.L) in Zhanjiang, Guangdong Province, were used to reconstruct the vegetation variations as well as human activities in the lake catchment over the past 3500 years. Carbon isotopic compositions (δ13C) of leaf wax n-alkanes (n-C29, n-C31 and n-C33) were predominantly lighter than-32‰before 1.7 ka BP, suggesting that a typically pure C3 ecosystem might exist before 1.7 ka BP; for example, carbon isotope average value of long-chain n-alkanes was -33.27 ‰ in 1.78 ka BP; after that δ13C values increased rapidly and significantly, carbon isotope value was-28.26‰in 1.63 ka BP, indicating the emergence and increase of C4 plants. C4 plants usually indicate an arid climate, however, the n-alkanes indices that both increased Paq and reduced ACL indicate a humid climate after 1.7 ka BP. This contradiction can be well explained by invoking anthropogenic sugarcane plantation in the catchment at 1.7 ka BP. Furthermore, when it comes to the isotope change of samples, we find

  15. Types of phreatomagmatic volcanoes in the western Snake River Plain, Idaho, USA

    Science.gov (United States)

    Godchaux, M.M.; Bonnichsen, B.; Jenks, M.D.

    1992-01-01

    The western Snake River Plain graben in southwestern Idaho includes a large hydrovolcanic field which was produced in late Miocene to Pleistocene time by the interaction of rising basaltic magmas with the waters and water-saturated deposits of an enormous freshwater lake, Lake Idaho. The phreatomagmatic volcanoes in this field may be grouped into three types: emergent, subaqueous and subaerial. Emergent volcanoes, which began erupting under water and built up above the lake level, are relatively large and symmetrical, are dominated by bedded tuffs and late magmatic deposits, and are excellent indicators of water depth at the time of the eruption. Subaqueous volcanoes, which never built up above the lake level, are relatively small and asymmetrical, are dominated by basal massive deposits, and are potentially useful in discriminating between deep- and very-deep-water settings. Subaerial volcanoes, which were formed when magmas intercepted buried aquifers and interacted explosively with water, are small tuff rings and maars with variable shapes, are composed of subequal (although variable) proportions of basal massive deposits, bedded tuffs and late magmatic deposits, and are useful in determining the stratigraphic successions underlying them. ?? 1992.

  16. Carbonatitic lavas in Catanda (Kwanza Sul, Angola): Mineralogical and geochemical constraints on the parental melt

    Science.gov (United States)

    Campeny, Marc; Kamenetsky, Vadim S.; Melgarejo, Joan C.; Mangas, José; Manuel, José; Alfonso, Pura; Kamenetsky, Maya B.; Bambi, Aurora C. J. M.; Gonçalves, Antonio O.

    2015-09-01

    A set of small volcanic edifices with tuff ring and maar morphologies occur in the Catanda area, which is the only locality with extrusive carbonatites reported in Angola. Four outcrops of carbonatite lavas have been identified in this region and considering the mineralogical, textural and compositional features, we classify them as: silicocarbonatites (1), calciocarbonatites (2) and secondary calciocarbonatites produced by the alteration of primary natrocarbonatites (3). Even with their differences, we interpret these lava types as having been a single carbonatite suite related to the same parental magma. We have also estimated the composition of the parental magma from a study of melt inclusions hosted in magnetite microphenocrysts from all of these lavas. Melt inclusions revealed the presence of 13 different alkali-rich phases (e.g., nyerereite, shortite, halite and sylvite) that argues for an alkaline composition of the Catanda parental melts. Mineralogical, textural, compositional and isotopic features of some Catanda lavas are also similar to those described in altered natrocarbonatite localities worldwide such as Tinderet or Kerimasi, leading to our conclusion that the formation of some Catanda calciocarbonatite lavas was related to the occurrence of natrocarbonatite volcanism in this area. On the other hand, silicocarbonatite lavas, which are enriched in periclase, present very different mineralogical, compositional and isotopic features in comparison to the rest of Catanda lavas. We conclude that its formation was probably related to the decarbonation of primary dolomite bearing carbonatites.

  17. 3D-Reconstruction of recent volcanic activity from ROV-video, Charles Darwin Seamounts, Cape Verdes

    Science.gov (United States)

    Kwasnitschka, T.; Hansteen, T. H.; Kutterolf, S.; Freundt, A.; Devey, C. W.

    2011-12-01

    As well as providing well-localized samples, Remotely Operated Vehicles (ROVs) produce huge quantities of visual data whose potential for geological data mining has seldom if ever been fully realized. We present a new workflow to derive essential results of field geology such as quantitative stratigraphy and tectonic surveying from ROV-based photo and video material. We demonstrate the procedure on the Charles Darwin Seamounts, a field of small hot spot volcanoes recently identified at a depth of ca. 3500m southwest of the island of Santo Antao in the Cape Verdes. The Charles Darwin Seamounts feature a wide spectrum of volcanic edifices with forms suggestive of scoria cones, lava domes, tuff rings and maar-type depressions, all of comparable dimensions. These forms, coupled with the highly fragmented volcaniclastic samples recovered by dredging, motivated surveying parts of some edifices down to centimeter scale. ROV-based surveys yielded volcaniclastic samples of key structures linked by extensive coverage of stereoscopic photographs and high-resolution video. Based upon the latter, we present our workflow to derive three-dimensional models of outcrops from a single-camera video sequence, allowing quantitative measurements of fault orientation, bedding structure, grain size distribution and photo mosaicking within a geo-referenced framework. With this information we can identify episodes of repetitive eruptive activity at individual volcanic centers and see changes in eruptive style over time, which, despite their proximity to each other, is highly variable.

  18. Linking magma composition with volcano size and eruptive style in basaltic monogenetic systems

    Science.gov (United States)

    Smith, I. E.; McGee, L. E.; Cronin, S. J.

    2012-12-01

    Magma composition, volcano size and eruptive style (together with vent locations) are the definitive parameters of basaltic monogenetic systems. These variables are not independent, but the relationships between them are complex. Monogenetic volcano fields that episodically erupt small-volume, discrete magma batches such as the Auckland Volcanic Field (AVF, northern New Zealand), typically represent primary mantle melts variably modified by near source processes. In such cases, where the volume of magma is small, eruption styles are strongly controlled by the interaction of magma with the surficial environment and this is determined by both magma volume and its rise rate. The magmatic compositional extremes of primitive magmas in the AVF define a spectrum ranging from strongly silica-undersaturated nephelinite to sub-alkalic basalt. Nephelinites are low SiO2 (~40 wt.%), highly incompatible-element enriched compositions, representing very low degrees of partial melting (indicates that all of these magmas are sourced within the same general mantle region at depths of 80-70 km. The two compositional extremes also define extremes in volume of magma and ultimately magma flux at the surface. The surficial environment of the AVF is characterized by highly water saturated sediments of variable competency and many pressurized aquifer systems. Where there is a combination of small volumes and low flux rates, environmental factors dominate and phreatomagmatic explosive eruptions ensue, forming tuff cones, rings and maars. Larger volumes and flux rates result in dry eruptions forming cinder cones and lava fields. Thus at a fundamental level defining magma source characteristics and temporal or spatial variation in these (such as cyclic or evolutionary trends) can inform better long term forecasts of surface eruption processes and thus should be more closely examined in hazard studies of monogentic fields.

  19. Monogenetic volcanic fields and their geoheritage values of western Saudi Arabia and their implication to holistic geoeducation projects locally and globally (Invited)

    Science.gov (United States)

    Nemeth, K.; Moufti, R.

    2013-12-01

    Monogeneitc volcanic fields are the most common manifestation of volcanism on Earth and other planets. They composed of small volume and short lived volcanoes each of them with a relatively simple eruption history. In spite of recent researches demonstrated complex, repeated and geochemically distinct eruption histories commonly associated with te formation of small-volume volcanoes, they are still considerred as volcanoes that are in human-scale and therefore ideal to use them as educational tools or part of volcanic geoheritage projects including geopark developments. In the western margin of the Kingdom of Saudi Arabia there are at least 9 intracontinental volcanic fields subparalell with the Red Sea Rift ranging from alkaline basaltic to basalt-trachyte bimodal dispersed volcanic systems. Among these volcanic fields the geoheritage value of three fields were recently evaluated and proposed that they are suitable for further development to establish the first volcanic geoparks in the Arabian Peninsula in the area of 1) Al Madinah (AMVF) 2) Kishb (KVF) and 3) Hutaymah Volcanic Fields (HVF). The AMVF offers a natural concept based on specific volcanic precinct ordering of its volcanic geoheritages from the most accessable and most common volcanism that is historically significant (eg. scoria and lava spatter cones with extensive lava fields) toward a more adventure geotourism style approach in remote, less common but more destructive type of volcanism (eg. trachytic explosion craters). In the contrary, the KVF is a perfect site where phreatomagmatic volcanism and their consequences were identified as a major driving force for further geopark developments. The HVF with its rich archaeological and cultural sites and superbly exposed variously eroded tuff rings and maars offer a good location to develop geoeducation programs to highlight short- and long-term climatic and hydrologic changes in an area a volcanic field evolved. The three Saudi projects also demonstrate

  20. From olivine nephelinite, basanite and basalt to peralkaline trachyphonolite and comendite in the Ankaratra volcanic complex, Madagascar: 40Ar/39Ar ages, phase compositions and bulk-rock geochemical and isotopic evolution

    Science.gov (United States)

    Cucciniello, Ciro; Melluso, Leone; le Roex, Anton P.; Jourdan, Fred; Morra, Vincenzo; de'Gennaro, Roberto; Grifa, Celestino

    2017-03-01

    The Ankaratra volcanic field covers an area of 3800 km2 in central Madagascar and comprises of lava flows, lava domes, scoria cones, tuff rings and maars emplaced at different ages (Miocene to Recent). The volcanic products include ultramafic-mafic (olivine-leucite nephelinite, basanite, alkali basalt, hawaiite and tholeiitic basalt), intermediate (mugearite and benmoreite) and felsic rocks (trachyphonolite, quartz trachyte and rhyolite), the latter often peralkaline. The 40Ar/39Ar determinations for mafic lavas yield ages of 17.45 ± 0.12 Ma, 16.63 ± 0.08 Ma and 8.62 ± 0.09 Ma, indicating a prolonged magmatic activity. The mineralogical and geochemical variations suggest that the magmatic evolution of the alkali basalt-hawaiite-mugearite-benmoreite-trachyte series can be accounted for by removal of olivine, feldspars, clinopyroxene, Fe-Ti oxides and accessory phases, producing residual trachytic and trachyphonolitic compositions mineralogically very similar to those of other volcanic areas and tectonic settings. The Ankaratra olivine leucite nephelinites, basanites and tholeiitic basalts do not seem to be associated with significant amounts of evolved comagmatic rocks. The 87Sr/86Sr (0.70504-0.71012), 143Nd/144Nd (0.51259-0.51244) and 206Pb/204Pb (17.705-18.563) isotopic ratios of trachytes and comendite are consistent with open-system processes. However, other trachyphonolites have 143Nd/144Nd (0.51280), 206Pb/204Pb (18.648), 207Pb/204Pb (15.582) and 208Pb/204Pb (38.795) similar to those of mafic rocks, suggesting differentiation processes without appreciable interaction with crustal materials. The Ankaratra volcanism is to be directly linked to a broadly E-W-trending intracontinental extension. A large-scale thermal anomaly, associated with an anomalously hot source region, is not required to explain the Cenozoic magmatism of Madagascar.

  1. Scientific Drilling in a Central Italian Volcanic District

    Directory of Open Access Journals (Sweden)

    Paola Montone

    2007-09-01

    Full Text Available The Colli Albani Volcanic District, located 15 km SE of Rome (Fig. 1, is part of the Roman Magmatic Province, a belt of potassic to ultra-potassic volcanic districts that developed along the Tyrrhenian Sea margin since Middle Pleistocene time (Conticelli and Peccerillo, 1992; Marra et al., 2004; Giordano et al., 2006 and references therein. Eruption centers are aligned along NW-SE oriented majorextensional structures guiding the dislocation of Meso-Cenozoic siliceous-carbonate sedimentary successions at the rear of the Apennine belt. Volcanic districts developed in structural sectors with most favorable conditions for magma uprise. In particular, the Colli Albani volcanism is located in a N-S shear zone where it intersects the extensional NW- and NE-trending fault systems. In the last decade, geochronological measurements allowed for reconstructions of the eruptive history and led to the classification as "dormant" volcano. The volcanic history may be roughly subdivided into three main phases marked by different eruptive mechanisms andmagma volumes. The early Tuscolano-Artemisio Phase (ca. 561–351 ky, the most explosive and voluminous one, is characterized by five large pyroclastic flow-forming eruptions. After a ~40-ky-long dormancy, a lesser energetic phase of activity took place (Faete Phase; ca. 308–250 ky, which started with peripheral effusive eruptions coupled with subordinate hydromagmatic activity. A new ~50-ky-long dormancypreceded the start of the late hydromagmatic phase (ca. 200–36 ky, which was dominated by pyroclastic-surge eruptions, with formation of several monogenetic or multiple maars and/or tuff rings.

  2. Spatial distribution of cones and satellite-detected lineaments in the Pali Aike Volcanic Field (southernmost Patagonia): insights into the tectonic setting of a Neogene rift system

    Science.gov (United States)

    Mazzarini, Francesco; D'Orazio, Massimo

    2003-07-01

    The relationships between the distribution and morphometric features of eruptive structures (scoria and spatter cones, maar, tuff rings) and the fracture network were investigated in the Pliocene-Quaternary Pali Aike Volcanic Field (southernmost Patagonia, Argentina-Chile). The alkali basaltic/basanitic magmas which erupted in this area have nearly primary magma compositions and often bear mantle xenoliths; hence magma ascent from deep-seated reservoirs was probably very fast, with no significant stagnation at crustal levels. Field surveys and satellite image analysis led to the identification of up to 467 eruptive structures and four main NW-SE, NE-SW, E-W and N-S fracture systems. The spatial distribution of eruptive cones and fractures was investigated through the computation of power-law exponents ( Df) for self-similar clustering. The self-similarity of cones and fractures was defined between lower and upper cut-offs which were in turn related to the thickness of the fractured mechanical layer. The fractal character of cones and fracture distribution (clustering) in the Pali Aike Volcanic Field area was thus correlated with crustal thickness. The self-similarity of fractures was used to establish the relative chronology of the detected fracture systems. The self-similar clustering exponent is highest in the E-W and NW-SE fracture systems ( Df=1.78 and 1.77, respectively), and lowest in the N-S system ( Df=1.65). The self-similar clustering of eruptive structures is well defined ( Df=1.45). The intense volcano-tectonic activity in the Pali Aike area marks a major Pliocene-Quaternary phase in the development of the Magellan Neogene Rift System.

  3. The well-known unknown photographer Jaan Klõšeiko / Ellu Maar

    Index Scriptorium Estoniae

    Maar, Ellu, 1982-

    2010-01-01

    Graafik ja fotograaf Jaan Klõšeikost, kes on 45 aastat jäädvustanud kunsti- ja kultuurisündmusi. Galerii Vaal kodulehel ilmunud J. Klõšeiko fotoseeriatest (12), fotod valis ja saatesõnad kirjutas J. Klõšeiko

  4. Ruimere toepassingsmogelijkheden landfarming van verontreinigde baggerspecie : het duurt even, maar de specie wordt echt schoon

    NARCIS (Netherlands)

    Harmsen, J.; Zweers, A.J.

    2009-01-01

    Bijna 20 jaar geleden is op de locatie Kreekraksluizen een experiment gestart om verontreinigde baggerspecie biologisch te reinigen met behulp van landfarming. De gereinigde baggerspecie ligt hier nog steeds en wordt nog gemonitored en dit heeft een unieke waarnemingsreeks opgeleverd

  5. Populariteit, maar niet geliefdheid, is gerelateerd aan risicogedrag van Nederlandse adolescenten

    NARCIS (Netherlands)

    Broek, N. van den; Deutz, M.H.F.; Franken, A.; Cillessen, A.H.N.

    2017-01-01

    Ondanks dat theoretisch en empirisch bewijs aantoont dat Amerikaanse en Australische adolescenten risicogedrag vertonen om sociale status te verwerven, is er weinig bekend over de relatie tussen risicogedrag en sociale status bij Europese adolescenten. De huidige studie onderzocht deze relatie

  6. Nostalgia Arhitektuurimuuseumis : kuldsed kuuekümnendad / Karen Jagodin ; interv. Ellu Maar

    Index Scriptorium Estoniae

    Jagodin, Karen, 1982-

    2007-01-01

    Näitusest "Kuuekümnendad. Eesti moodne arhitektuur" ja sisearhitektide Väino Tamme ning Vello Asi loomingu näitusest Eesti Arhitektuurimuuseumis. Kuraatorid Karin Hallas-Murula ja Karen Jagodin. Eesti 1960. aastate sisearhitektuurist

  7. Veel haring, maar vrijwel geen jonge kabeljauw: International Bottom Trawl Survey 2003

    NARCIS (Netherlands)

    Heessen, H.J.L.

    2003-01-01

    Onderzoeksvaartuigen hebben de jaarlijkse International Bottom Trawl Survey (IBTS) uitgevoerd om een indruk te krijgen van de jongste jaarklassen van jonge haring, sprot en rondvis. Overzicht van de bestanden van kabeljauw, schelvis, wijting en haring 1978-2002

  8. Nostalgia Arhitektuurimuuseumis : kuldsed kuuekümnendad / Karen Jagodin ; interv. Ellu Maar

    Index Scriptorium Estoniae

    Jagodin, Karen, 1982-

    2007-01-01

    Näitusest "Kuuekümnendad. Eesti moodne arhitektuur" ja sisearhitektide Väino Tamme ning Vello Asi loomingu näitusest Eesti Arhitektuurimuuseumis. Kuraatorid Karin Hallas-Murula ja Karen Jagodin. Eesti 1960. aastate sisearhitektuurist

  9. Duurzaam maar niet biologisch. Certificeren van duurzaamheid in de grondgebonden landbouw

    NARCIS (Netherlands)

    Feitsma, Louis

    2008-01-01

    Duurzaam is een trend. Zo ook in de landbouw. Het aantal innovatieve initiatieven met een duurzaam kaliber in de agrarische sector stijgt. In tegenstelling tot biologische initiatieven en producten, zijn duurzame initiatieven nog niet toetsbaar en erkend. Fiscaal is het moeilijk duurzame initiatieve

  10. Dieetmarkt slankt zelf af: vraag naar maaltijdvervangers daalt dramatisch: doe maar gewoon lijkt het credo

    NARCIS (Netherlands)

    Dagevos, H.; Pronk, A.

    2008-01-01

    Het succes van Sonja Bakker en een groeiende aandacht voor gezondheid wekken de indruk dat we in Nederland massaal aan het lijnen zijn. Het lijkt logisch te veronderstellen dat de markt voor dieetproducten hier garen bij spint en volop in de lift zit. Niets blijkt echter minder waar. Hoewel cijfers

  11. Populariteit, maar niet geliefdheid, is gerelateerd aan risicogedrag van Nederlandse adolescenten

    NARCIS (Netherlands)

    Broek, N. van den; Deutz, M.H.F.; Franken, A.; Cillessen, A.H.N.

    2017-01-01

    Ondanks dat theoretisch en empirisch bewijs aantoont dat Amerikaanse en Australische adolescenten risicogedrag vertonen om sociale status te verwerven, is er weinig bekend over de relatie tussen risicogedrag en sociale status bij Europese adolescenten. De huidige studie onderzocht deze relatie daaro

  12. 'Mensen ... worden niet geboren maar gevormd': Erasmus en het principe van de opvoeding

    Directory of Open Access Journals (Sweden)

    J. van Herwaarden

    2007-01-01

    Full Text Available ‘People... are not born but formed’: Erasmus and the principle of educating young peopleIn Erasmus’ opinion human beings ware created by God with the propensity for reason that enables them to develop the potential that nature has given them. Breeding and education should be initiated as soon as possible after birth and should focus on making the child think and act independently, within the framework of christian pietas. Language and letters - the bonae litterae - were indispendable instruments for what was named the studia humanitatis, which moulded people into citizens of the world, marked by an acute awareness of their obligations to the Christian community.

  13. Limnological studies on the Pretoria Salt Pan, a hypersaline maar lake

    CSIR Research Space (South Africa)

    Ashton, PJ

    1983-01-01

    Full Text Available The Pretoria Salt pan is shallow and alkaline with pronounced mesothermy at a depth of between 0.55 and 0.7 metres. Secchi disc transparencies ranged from 7 to 19 cm. Endorheic or closed drainage basins are widely distributed in many climate...

  14. Peenteelt wordt uitdaging; nog maar één middel tegen wortelvlieg

    NARCIS (Netherlands)

    Rozen, van K.; Broek, van den R.C.F.M.

    2011-01-01

    Hoe zal het dit jaar gaan met de wortelvlieg? Het enig toegelaten insecticide mag alleen beperkt worden toegepast. Is dit voldoende om de schade te beheersen? Slim telen op basis van teeltdoel, teeltduur en levenscyclus is de uitdaging voor de huidige peenteelt. Inzet van monitoring wordt steeds bel

  15. Compensatie eigen risico: nooit van gehoord, maar ik denk wel dat ik er recht op heb.

    NARCIS (Netherlands)

    Reitsma-van Rooijen, M.; Jong, J. de

    2011-01-01

    There are many different compensatory arrangements for health related expenses. It is important that these are executed correctly, to prevent that people who are entitled to compensation do not receive the compensation and that people claim the compensation who are not entitled to receive a compensa

  16. Voedsel labelen met land van herkomst: leuk, maar geen voorwaarde. Onderzoek onder Nederlandse consumenten

    NARCIS (Netherlands)

    Haaster-de Winter, van M.A.; Ruissen, A.

    2012-01-01

    De vermelding van het land van herkomst is in de Europese Unie verplicht voor enkele agrarische producten, te weten: rundvlees, honing, verse groenten en fruit en olijfolie. In Nederland wordt het land van herkomst buiten de verplichte etikettering van deze productgroepen nog nauwelijks vermeld.

  17. 'Mensen ... worden niet geboren maar gevormd': Erasmus en het principe van de opvoeding

    Directory of Open Access Journals (Sweden)

    J. van Herwaarden

    2007-01-01

    Full Text Available ‘People... are not born but formed’: Erasmus and the principle of educating young peopleIn Erasmus’ opinion human beings ware created by God with the propensity for reason that enables them to develop the potential that nature has given them. Breeding and education should be initiated as soon as possible after birth and should focus on making the child think and act independently, within the framework of christian pietas. Language and letters - the bonae litterae - were indispendable instruments for what was named the studia humanitatis, which moulded people into citizens of the world, marked by an acute awareness of their obligations to the Christian community.

  18. Balans van 25 jaar arbeids- en organisatiepsychologie : nieuwe thema's en methoden, maar praktische relevantie onder druk

    NARCIS (Netherlands)

    Smulders, P.; Schouteten, R.

    2009-01-01

    Op basis van reviewartikelen, trend- en inhoudsanalyses poogt dit artikel een overzicht te geven van 25 jaar A&O-psychologie. Daarbij gaat de aandacht uit naar zowel nationale als internationale ontwikkelingen. Geconcludeerd wordt dat er grote verschillen bestaan tussen de Verenigde Staten, het Vere

  19. De commons zijn niet overal een tragedie, maar wel in het Groene Hart

    NARCIS (Netherlands)

    L.J. de Haan (Leo)

    1995-01-01

    textabstractIn de Tragedy of the Commons voert Hardin (1968) een denkbeeldig dorp ten tonele, waar de gemeenschappelijke weidegronden verloren gaan door overheersend eigenbelang van de herders. Privatisering of vergaande regulering van het gebruik zouden de enige oplossingen zijn. In dit artikel wor

  20. Terug naar af?: PEC wil vernieuwing, maar vertrouwt voor marktwerking op de verkeerde soort concurrentie

    NARCIS (Netherlands)

    Dorée, André; Boes, Hans

    2003-01-01

    In drie eerdere artikelen gingen Dorée en Boes in op de ontwikkelingen rond de parlementaire enquête. Nu het stof rondom het rapport optrekt, staan ze stil bij het recept waarmee de commissie gezonde marktwerking en mededinging wil herstellen. De commissie lijkt van concurrentie een te éénzijdig bee

  1. The well-known unknown photographer Jaan Klõšeiko / Ellu Maar

    Index Scriptorium Estoniae

    Maar, Ellu, 1982-

    2010-01-01

    Graafik ja fotograaf Jaan Klõšeikost, kes on 45 aastat jäädvustanud kunsti- ja kultuurisündmusi. Galerii Vaal kodulehel ilmunud J. Klõšeiko fotoseeriatest (12), fotod valis ja saatesõnad kirjutas J. Klõšeiko

  2. Computerbeveiliging kijkt naar buiten, maar het gevaar komt van binnen de organisatie!

    NARCIS (Netherlands)

    Luiijf, H.A.M.

    1997-01-01

    Ieder bedrijf wil tegenwoordig op het Internet. De voordelen zijn bekend. Wereldwijde, goedkope en snelle communicatie met tientallen miljoenen computers en toegang tot een overvloed aan gratis beschikbare informatie. De nadelen zijn minder duidelijk. Aansluiting van de computers op het voor het Int

  3. Lithofacies, eruptive phases and processes of Udo monogenetic multiple volcano near Jeju Island, South Sea, Korea

    Institute of Scientific and Technical Information of China (English)

    HWANG Sang-koo

    2004-01-01

    A monogenetic multiple volcano was emergent on Udo island, 3 km offthe sea shore of the eastern promontory of Jeju Island, South Sea,Korea. All of the preserved volcanic successions occur in a regular pattern of sequences,representing an excellent example of an eruptive cycle. The island represents volcanic stratigraphy that comprises a horseshoe-shaped tuff cone, a nested cinder cone on the crater floor of the tuff cone,and basalt lavas which extend northwest from the moat between tuff and cinder cones. The volcanic stratigraphy suggests eruptive styles that start with emergent Surtseyan eruption, progressing through Strombolian eruption and end with lava effusion.

  4. "Absindijoojad" ja "Eesti neiu" graafikute pilgu läbi / Enno Ootsing, Vive Tolli ; intervjueerinud Ellu Maar

    Index Scriptorium Estoniae

    Ootsing, Enno, 1940-

    2007-01-01

    Graafikud Enno Ootsing puugravüüri spetsialistina ja Vive Tolli sügavtrükispetsialistina Eduard Wiiralti töödest, erinevatest graafikatehnikatest ja nende iseärasustest, värvilise kõrg- ja sügavtrüki tegemise tehnilisest poolest ning tõmmisteks sobivatest paberitest

  5. Complex subvolcanic magma plumbing system of an alkali basaltic maar-diatreme volcano (Elie Ness, Fife, Scotland)

    Science.gov (United States)

    Gernon, T. M.; Upton, B. G. J.; Ugra, R.; Yücel, C.; Taylor, R. N.; Elliott, H.

    2016-11-01

    Alkali basaltic diatremes such as Elie Ness (Fife, Scotland) expose a range of volcanic lithofacies that points to a complex, multi-stage emplacement history. Here, basanites contain phenocrysts including pyrope garnet and sub-calcic augites from depths of 60 km. Volcanic rocks from all units, pyroclastic and hypabyssal, are characterised by rare earth element (REE) patterns that show continuous enrichment from heavy REE (HREE) to light REE (LREE), and high Zr/Y that are consistent with retention of garnet in the mantle source during melting of peridotite in a garnet lherzolite facies. Erupted garnets are euhedral and unresorbed, signifying rapid ascent through the lithosphere. The magmas also transported abundant pyroxenitic clasts, cognate with the basanite host, from shallower depths ( 35-40 km). These clasts exhibit wide variation in texture, mode and mineralogy, consistent with growth from a range of compositionally diverse melts. Further, clinopyroxene phenocrysts from both the hypabyssal and pyroclastic units exhibit a very wide compositional range, indicative of polybaric fractionation and magma mixing. This is attributed to stalling of earlier magmas in the lower crust - principally from 22 to 28 km - as indicated by pyroxene thermobarometry. Many clinopyroxenes display chemical zoning profiles, occasionally with mantles and rims of higher magnesium number (Mg#) suggesting the magmas were mobilised by juvenile basanite magma. The tuffs also contain alkali feldspar megacrysts together with Fe-clinopyroxene, zircon and related salic xenoliths, of the 'anorthoclasite suite' - inferred to have crystallised at upper mantle to lower crustal depths from salic magma in advance of the mafic host magmas. Despite evidence for entrainment of heterogeneous crystal mushes, the rapidly ascending melts experienced negligible crustal contamination. The complex association of phenocrysts, megacrysts and autoliths at Elie Ness indicates thorough mixing in a dynamic system immediately prior to explosive diatreme-forming eruptions.

  6. "Absindijoojad" ja "Eesti neiu" graafikute pilgu läbi / Enno Ootsing, Vive Tolli ; intervjueerinud Ellu Maar

    Index Scriptorium Estoniae

    Ootsing, Enno, 1940-

    2007-01-01

    Graafikud Enno Ootsing puugravüüri spetsialistina ja Vive Tolli sügavtrükispetsialistina Eduard Wiiralti töödest, erinevatest graafikatehnikatest ja nende iseärasustest, värvilise kõrg- ja sügavtrüki tegemise tehnilisest poolest ning tõmmisteks sobivatest paberitest

  7. 'Het Afghaanse volk heeft onze maar ook uw steun nodig' : de rol van buitenlands beleid in de Amerikaanse presidentsverkiezingen

    NARCIS (Netherlands)

    Janssens, R.

    2008-01-01

    Ruud Janssens presents his essay 'The Afghan People need Our Troops and Your Troops': The role of foreign policy in the American Presidential Elections. Given the Global War on Terror, and specifically the American military presence in Iraq and Afghanistan, foreign policy plays a prominent role in t

  8. Collective but individual. Electrical engineering, monitoring and rules; Collectie maar toch individueel. Elektrotechniek/meet- en regelgeving

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-09-01

    An overview is given of the components and performance of the Synergyr system, developed by Siemens Building Technologies and the Landis and Staefa Division. The Synergyr system is a monitoring and control system that provides a correct heat distribution and recording of the supplied energy. Based on Synergyr, Electrabel Distributie Vlaanderen (Electrabel Distribution for Flanders in Belgium) developed a system for individual cost calculation and invoicing. Under the name GCV (Dutch abbreviation for individualized collective heating) the total system can be applied in large residential buildings.

  9. Net maar diere? ʼn Tematiese oorsig van die plek van die diereryk in die skepping volgens geselekteerde Skrifgedeeltes

    Directory of Open Access Journals (Sweden)

    Jannie Du Preez

    2011-09-01

    Full Text Available A thematic survey of the place of the animal kingdom in God’s world according to
    some Scripture passages
    In a time of growing ecological awareness it may prove valuable to trace the place
    which the animal kingdom according to the Scriptures takes in God’s world. The
    relevant material unfolds as follows:
    Every animal unique;
    The Creator’s compassion on animals;
    Animals as examples to humans;
    Animal images for God;
    Animal images for God’s people;
    The messianic kingdom sketched by way of animal images;
    The significance of animal sacrifices in salvation history;
    Animal service during Jesus’ earthly ministry;
    The “Prayer relationship” between Creator and animals.
    As God’s image bearers, who have been appointed to rule over the animal world
    (Gen. 1: 27-28, it is our duty and privilege to behave in such a way towards them
    that they will thereby be better enabled to fulfil the significance of their existence in
    God’s world.

  10. Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review

    Science.gov (United States)

    Lexa, Jaroslav; Seghedi, Ioan; Németh, Karoly; Szakács, Alexandru; Koneĉny, Vlastimil; Pécskay, Zoltan; Fülöp, Alexandrina; Kovacs, Marinel

    2010-09-01

    Neogene to Quaternary volcanic/magmatic activity in the Carpathian-Pannonian Region (CPR) occurred between 21 and 0.1 Ma with a distinct migration in time from west to east. It shows a diverse compositional variation in response to a complex interplay of subduction with rollback, back-arc extension, collision, slab break-off, delamination, strike-slip tectonics and microplate rotations, as well as in response to further evolution of magmas in the crustal environment by processes of differentiation, crustal contamination, anatexis and magma mixing. Since most of the primary volcanic forms have been affected by erosion, especially in areas of post-volcanic uplift, based on the level of erosion we distinguish: (1) areas eroded to the basement level, where paleovolcanic reconstruction is not possible; (2) deeply eroded volcanic forms with secondary morphology and possible paleovolcanic reconstruction; (3) eroded volcanic forms with remnants of original morphology preserved; and (4) the least eroded volcanic forms with original morphology quite well preserved. The large variety of volcanic forms present in the area can be grouped in a) monogenetic volcanoes and b) polygenetic volcanoes and their subsurface/intrusive counterparts that belong to various rock series found in the CPR such as calc-alkaline magmatic rock-types (felsic, intermediate and mafic varieties) and alkalic types including K-alkalic, shoshonitic, ultrapotassic and Na-alkalic. The following volcanic/subvolcanic forms have been identified: (i) domes, shield volcanoes, effusive cones, pyroclastic cones, stratovolcanoes and calderas with associated intrusive bodies for intermediate and basic calclkaline volcanism; (ii) domes, calderas and ignimbrite/ash-flow fields for felsic calc-alkaline volcanism and (iii) dome flows, shield volcanoes, maars, tuffcone/tuff-rings, scoria-cones with or without related lava flow/field and their erosional or subsurface forms (necks/ plugs, dykes, shallow intrusions

  11. The Pali Aike Volcanic Field, Patagonia: slab-window magmatism near the tip of South America

    Science.gov (United States)

    D'Orazio, Massimo; Agostini, Samuele; Mazzarini, Francesco; Innocenti, Fabrizio; Manetti, Piero; Haller, Miguel J.; Lahsen, Alfredo

    2000-06-01

    The Pali Aike Volcanic Field (PAVF) represents the southernmost occurrence of the Cenozoic back-arc Patagonian Plateau Lavas. Its activity (Pliocene-Recent) started forming tabular lavas followed by the growth of about 470 essentially monogenetic volcanic centers (tuff-rings, maars, spatter and scoria cones). Azimuths of cone alignment, cone elongation and morphologic lineations show prevailing ENE-WSW and NW-SE trends. Erupted products consist mainly of alkaline basalt and basanite, with minor olivine basalt. PAVF rocks are quite primitive in composition (average Mg#=66, Ni=220 ppm and Cr=313 ppm) with relatively high TiO 2 (average 3.0 wt.%). Ultramafic garnet- and/or spinel-bearing xenoliths are found within PAVF volcanics. Chondrite-normalized REE patterns are significantly LREE-enriched and almost rectilinear [(La/Yb) N=10.9-21.0]. Primordial mantle-normalized distributions of incompatible trace elements, as well as Sr and Nd isotope ratios ( 87Sr/ 86Sr=0.70317-0.70339, 143Nd/ 144Nd=0.51290-0.51294), show values typical of intra-plate basalts, despite the fact that these rocks occur only 200 km east of the Andean Cordillera. Primary magmas were generated from a fertile garnet-bearing asthenospheric source at P=1.9-2.9 GPa and T=1420-1470°C. The data suggest a geodynamic model that implies sub-slab asthenosphere flow through a slab window, which started opening below this sector of South America 14 m.y. ago as a consequence of the collision of the Chile Ridge with the Chile Trench. The trailing edge of the Nazca Plate crossed below the Pali Aike area at 9-10 Ma, that is 6-5 m.y. before the onset of the volcanic activity. We hypothesize that this time delay resulted from changes in the kinematics of the South America-Scotia transform plate boundary which only allowed the Pali Aike magmas to rise after about 4 m.y.

  12. Investigating the explosivity of shallow sub-aqueous basaltic eruptions

    Science.gov (United States)

    Murtagh, R.; White, J. D. L.

    2009-04-01

    Volcanic eruptions produce pyroclasts containing vesicles, clearly implying exsolution of volatiles from the magma has occurred. Our aim is to understand the textural characteristics of vesiculated clasts as a quantitative indicator of the eruptive behaviour of a volcano. Assessing water's role in volatile degassing and outgassing has been and is being well documented for terrestrial eruptions; the same cannot be said, however, for their shallow subaqueous counterparts. The eruptive behaviour of Surtseyan volcanoes, which include both subaqueous and subaerial phases (for example, the type-location Surtsey, Iceland in 1963) is under investigation here and for good reason. Volcanic eruptions during which water and basaltic magma come into contact appear to ignite violent eruptions of many of the small "monogenetic" volcanoes so abundant on Earth. A key problem remains that detailed conditions of water-magma interactions are not yet fully understood. Field samples obtained from exposed sequences deposited originally in a subaqueous environment allow for the necessary analysis of lapilli. With the aid of experimental data, mathematical modelling and terrestrial analogues the ambition is to unravel volatile degassing, ascent histories and fragmentation processes, allowing us ultimately to identify both the role water plays in the explosivity of shallow subaqueous eruptions, and the rise history of magma to the point of interaction. The first site, Pahvant Butte is located in southwest Utah, U.S. It is a well preserved tuff cone overlying a subaqueously deposited mound of glassy ash composed of sideromelane and tachylite. It was erupted under ~85m of water into Lake Bonneville approximately 15,300 years ago. Our focus is on samples collected from a well-bedded, broadly scoured coarse ash and lapilli lithofacies on the eastern flank of the edifice. Vesicularity indices span from 52.6% - 60.8%, with very broad vesicularity ranges, 20.6% - 81.0% for one extreme sample. The

  13. The reinterpretation of Leone Lake sediments as a pyroclastic surge deposit and its tectonic significance. [volcanics in Cascade Range of Oregon

    Science.gov (United States)

    Mcdonough, W. F.; Waibel, A. F.; Gannett, M. W.

    1984-01-01

    The Leone Lake sediments, previously interpreted as being of fluvial and lacustrine origin, are reinterpreted as subaerial pyroclastic surge and palagonite tuff cone deposits. This conclusion is based on bedforms, particle morphology, the primary mineral assemblage, and the nature and mineralogy of the alteration. The principal characteristics of the pyroclastic surge units and palagonite tuffs are examined, and the tectonic significance of the reinterpretation is briefly discussed.

  14. RemBrand Fase 1 ; Niet harder rijden, maar voorkomen en slimmer bestrijden. Quick Research Scan naar een model voor de operationeleen maatschappelijke prestaties gericht op brandveiligheid

    NARCIS (Netherlands)

    Dijk, W.J.; Don, J.A.; Butter, M.; Bousché, H.F.

    2013-01-01

    Brandveiligheid is een brede maatschappelijke verantwoordelijkheid die niet exclusief aan te brandweer valt toe te bedelen. Op dit moment voorziet de Wet Veiligheidsregio’s niet in een vorm van maatschappelijke verantwoording die rekening houdt met zowel het blussen alsook het voorkomen, beperken en

  15. The feasibility of a 20% CO sub 2 emission reduction in 2005. 20% CO sub 2 -emissiereductie in 2005: Moeilijk maar haalbaar

    Energy Technology Data Exchange (ETDEWEB)

    Okken, P.A.; Boonekamp, P.G.M.; Rouw, M.; Ybema, J.R. (Energy Study Centre, Netherlands Energy Research Foundation, Petten (Netherlands))

    1991-09-01

    Changes in the Dutch energy economy form an important part of the CO{sub 2} reduction policy, which has been presented to the Lower chamber of the Dutch Parliament August 1991 in the Climate Change Bill. An important chapter of the Bill is based on a study, in which a quantitative elaboration of a baseline for the year 2005 to realize a 20% reduction of CO{sub 2} emission has been carried out. A separate abstract has been prepared of this study (report number ECN-C--91-045). In this article attention is paid to the Dutch CO{sub 2} emission, the options to reduce CO{sub 2} emission, and the investment costs for the options to reduce CO{sub 2} emission in the year 2005. 2 figs., 3 tabs., 8 refs.

  16. Breder screenen op hemoglobinopathie: niet alleen na de geboorte testen op HbP, maar ook daarvóór.

    NARCIS (Netherlands)

    Cornel, M.C.; Detmar, S.; Plass, A.M.C.; Moerman, D.; Waarlo, A.J.; Kinderen, M. de; Giordano, P.C.

    2009-01-01

    Vrijwel overal ter wereld wordt dragerschapsscreening op hemoglobinopathie aanbevolen tijdens of voorafgaand aan de zwangerschap met het oog op reproductieve keuzes. In Nederland wordt sinds 2007 sikkelcelziekte neonataal opgespoord ter preventie van complicaties bij het kind (hielprik). Ook dragers

  17. Morphology of cone-fields in SW Elysium Planitia - Traces of hydrothermal venting on Mars?

    Science.gov (United States)

    Lanz, J. K.; Saric, M. B.

    2008-09-01

    Introduction Small cone-shaped features with summit pits can be found in several regions on Mars; mainly in Isidis Planitia; Elysium Planitia; Amazonis Planitia; Acidalia Planitia; in the Cydonia Region; in Cerberus Planum; the Phlegra Montes and on several volcanic flanks. They vary greatly in size and morphology and have been compared to terrestrial features of various origins; namely (1) cinder cones (e.g. [1]), (2) tuff cones or tuff rings (e.g. [2]), (3) rootless cones (pseudocraters) (e.g. [3], [4]), (4) pingos (e.g. [5], [6]) and (5) mud volcanoes (e.g. [7]). They are often found near volcanic centers and large lava fields or cluster in regions where the volatile content of the Martian regolith was/is supposedly high. This has led to the assumption that (ground-) water or ground ice was a trigger or driving force of cone formation. They could therefore, be an important indicator of the history of water on the planet. We have studied an area in western Elysium Planitia, bordering the Aeolis Planum plateau, which exhibits a large number of pitted cones, ridges and dome-like structures. Their distribution and morphology differs strongly from pitted cones elsewhere in Elysium Planitia, which have mainly been interpreted as hydrovolcanic rootless cones, and from other regions on Mars. Based on our observations, we present an alternative model for cone formation in the study area that might hint towards hydrothermal processes in the Aeolis Planum region and possibly young igneous activity. Aeolis Planum Cones The Aeolis Planum pitted cones (referred to as APCs from now on) cluster along the southern edges of the broad shallow valley that borders the Aeolis Planum Formation (APF) to the north. Cones along the northern edges of the valley are rare and can only be found in association with APF remnants where they strongly resemble the cones in the south. Along the southern border the cone coverage is almost continuous, describing a narrow band approximately 2 to 3 km

  18. The Western Arabian intracontinental volcanic fields as a potential UNESCO World Heritage site

    Science.gov (United States)

    Németh, Károly; Moufti, Mohammed R.

    2017-04-01

    UNESCO promotes conservation of the geological and geomoprhological heritage through promotion of protection of these sites and development of educational programs under the umbrella of geoparks among the most globally significant ones labelled as UNESCO Global Geoparks. UNESCO also maintains a call to list those natural sites that provide universal outstanding values to demonstrate geological features or their relevance to our understanding the evolution of Earth. Volcanoes currently got a surge in nomination to be UNESCO World Heritage sites. Volcanic fields in the contrary fell in a grey area of nominations as they represents the most common manifestation of volcanism on Earth hence they are difficult to view as having outstanding universal values. A nearly 2500-km long 300-km wide region of dispersed volcanoes located in the Western Arabian Penninsula mostly in the Kingdom of Saudi Arabia form a near-continuous location that carries universal outstanding value as one of the most representative manifestation of dispersed intracontinental volcanism on Earth to be nominated as an UNESCO World Heritage site. The volcanic fields formed in the last 20 Ma along the Red Sea as group of simple basaltic to more mature and long-lived basalt to trachyte-to-rhyolite volcanic fields each carries high geoheritage values. While these volcanic fields are dominated by scoria and spatter cones and transitional lava fields, there are phreatomagmatic volcanoes among them such as maars and tuff rings. Phreatomagmatism is more evident in association with small volcanic edifices that were fed by primitive magmas, while phreatomagmatic influences during the course of a larger volume eruption are also known in association with the silicic eruptive centres in the harrats of Rahat, Kishb and Khaybar. Three of the volcanic fields are clearly bimodal and host small-volume relatively short-lived lava domes and associated block-and-ash fans providing a unique volcanic landscape commonly not

  19. The Rise and Fall of a Surtseyan Volcano: 2005 AD Eruption of Ambae (vanuatu, Sw-Pacific

    Science.gov (United States)

    Nemeth, K.

    2011-12-01

    On November 27th 2005 vapour plumes and minor ash columns emerged from the summit of Ambae. By the 3rd December, subaqueous explosive eruptions were confirmed in Lake Vui caldera lake and an island ~10 m high and ~100 m long emerged. Every 30 seconds an explosion took place, forming dense "cock's-tail" jets of steaming rock debris up to ~100 m high. These jets were initially black, but the condensing steam turned the clouds white as they collapsed back into Lake Vui, forming base surges that travelled with a speed of ~50-100 m/s over not more than 200 m from the vent. Debris jets were charged with water and mud and appeared to contain only rare large (jets were vertical and ejected material fell back commonly into the vent zone. Base surges formed especially after larger eruptive bursts, and travelled about 150 m away from their source before stalling. By the 8th December, a tephra apron (~70 m high) had grown to form an elliptical island, which was still open to the caldera lake. Since 5th December, the vent zone had shifted north-westward by 100-150 m. Eruptions still emanated from a subaqueous vent. Along with the debris jets, subaqueous pyroclastic density current activity continued on a larger scale than before, generating surface waves on the lake with amplitudes of ~1 m. The connection between the crater and caldera lake was maintained by subaqueous mass-wasting of the edifice. Larger explosive events initiated pyroclastic surges that covered the whole growing tuff cone. By the 12th December, the frequency of the individual explosions had dropped (3-5 per minute). They were more energetic, forming higher plumes reaching >200 m in height and containing large amounts of juvenile pyroclasts. The tuff cone had reached ~100 m in height by this time in its western rim. On the 13th December, energetic surges were witnessed that travelled 2-3 times farther than during the initial phase of the eruption, reaching at least 300 m from the vent. After the 13th December

  20. Physical Volcanology and Hazard Analysis of a Young Volcanic Field: Black Rock Desert, Utah, USA

    Science.gov (United States)

    Hintz, A. R.

    2009-05-01

    The Black Rock Desert volcanic field, located in west-central Utah, consists of ~30 small-volume monogenetic volcanoes with compositions ranging from small rhyolite domes to large basaltic lava flow fields. The field has exhibited bimodal volcanism for > 9 Ma with the most recent eruption of Ice Springs volcano ˜ 600 yrs ago. Together this eruptive history along with ongoing geothermal activity attests to the usefulness of a hazard assessment. The likelihood of a future eruption in this area has been calculated to be ˜ 8% over the next 1 Ka (95% confidence). However, many aspects of this field such as the explosivity and nature of many of these eruptions are not well known. The physical volcanology of the Tabernacle Hill volcano, suggests a complicated episodic eruption that may have lasted up to 50 yrs. The initial phreatomagmatic eruptions at Tabernacle Hill are reported to have begun ~14 Ka. This initial eruptive phase produced a tuff cone approximately 150 m high and 1.5 km in diameter with distinct bedding layers. Recent mapping and sampling of Tabernacle Hill's lava field, tuff cone and intra-crater deposits were aimed at better constraining the eruptive history, physical volcanology, and explosive energy associated with this eruption. Blocks ejected during the eruption were mapped and analyzed to yield minimum muzzle velocities of 60 - 70 meters per second. These velocities were used in conjunction with an estimated shallow depth of explosion to calculate an energy yield of ˜ 0.5 kT.

  1. Vredemakers as kinders van God (Matt 5:9): 'n Pragmaties ...

    African Journals Online (AJOL)

    24 Jul 2015 ... Department of New. Testament Studies, Faculty ... Testament, maar ook – sover my kennis strek – in antieke Griekse letterkunde.1 ..... noem, maar nie in Fitzmyer en Harrington (1978) se Manual of Palesfinian Aramaic.

  2. Prize something, including quality. The price of supply interruption. On the search for {phi}. Technical report; Op prijs gesteld, maar ook op kwaliteit. De prijs van stroomonderbrekingen. Op zoek naar {phi}. Technisch rapport

    Energy Technology Data Exchange (ETDEWEB)

    Baarsma, B.E.; Berkhout, P.H.G.; Hop, J.P.

    2004-04-01

    The Dutch Office of Energy Regulation (DTe) plans to adjust the present regulations with regard to regional electricity network companies. In 2002 an integrated model for pricing and quality regulations is drafted, which is expected to be implemented in 2005. This report serves as input for such a model. Quality is defined in terms of electricity supply disruptions. The aim of the study on the title subject is to determine prices for different types of power supply disruptions. The study is based on a survey among 12,400 households and nearly 2,500 small and medium-sized businesses in the Netherlands. [Dutch] De Dienst uitvoering en Toezicht energie (DTe) is voornemens om de huidige regelgeving ten aanzien van de regionale elektriciteitsnetbedrijven aan te passen. Hiertoe zijn in 2002 verkenningen voor een geintegreerd prijs- en kwaliteitsreguleringsmodel opgesteld, dat naar verwachting begin 2005 worden ingevoerd. Dit rapport dient als input voor het kwaliteitsreguleringsmodel. Kwaliteit is hier gedefinieerd in termen van stroomonderbrekingen. Het doel van het onderzoek is om prijskaartjes vast te stellen voor verschillende soorten stroomonderbrekingen. Zo kunnen de onderbrekingskosten verschillen afhankelijk van bijvoorbeeld het tijdstip (dagdeel, dag van de week, seizoen), de duur van de onderbreking, het wel of niet ontvangen van een waarschuwing vooraf en het aantal onderbrekingen. Het onderzoek is gebaseerd op een enquete onder 12.400 huishoudens en bijna 2500 MKB-bedrijven.

  3. Higher air quality through cleaner maritime shipping. IMO decree for less SO2, but more CO2; Gezondere lucht door schoner varen op zee. IMO-besluit betekent minder SO2, maar meer CO2

    Energy Technology Data Exchange (ETDEWEB)

    Dame, E. [Department Energy and Environment, Directorate-General Environment, European Commission, Brussels (Belgium); Meijer, H. [Department Clean Air and Transport, Directorate-General Environment, European Commission, Brussels (Belgium)

    2008-07-01

    In October, the International Maritime Organisation (IMO) will take the definitive decision that maritime shipping must decrease their emissions of sulphur dioxide (SO2) and nitrous oxides (NOx). At the same time this will also lead to less particulate matter. This article addresses the environmental consequences of this radical IMO decision. The total CO2 emission will increase, for example. The health benefits for European citizens, the cost of these measures and the influence on European legislation will also be addressed. [mk]. [Dutch] De Internationale Maritieme Organisatie (IMO) zal in oktober definitieve besluiten dat de zeescheepvaart minder zwaveldioxide (SO2) en stikstofoxiden (NOx) gaat uitstoten. En passant levert dit ook minder fijn stof op. Dit artikel gaat in op de milieugevolgen die verband houden met het ingrijpende IMO-besluit. Zo zal bijvoorbeeld de totale uitstoot van CO2 omhoog gaan. Ook de gezondheidswinst voor de Europese burgers, de kosten van de maatregelen en de invloed op Europese regelgeving worden belicht.

  4. ‘Als gy maar schérp wordt, zo zyn wy, én gy voldaan.’ Rationalistische ideeën van het kunstgenootschap Nil Volentibus Arduum 1669-1680

    NARCIS (Netherlands)

    Holzhey, T.

    2014-01-01

    Dit proefschrift analyseert de activiteiten en werken van het Amsterdamse kunstgenootschap Nil Volentibus Arduum (Waar een wil is, is een weg) gedurende de eerste tien jaar van zijn bestaan, tegen de achtergrond van het rationalisme. Meerdere oprichtingsleden hingen de opvattingen van rationalistisc

  5. 东北四海龙湾玛珥湖沉积物纹层计年与137Cs、210Pb测年%VARVECHRONOLOGY AND RADIOMETRIC DATING (137Cs,210Pb)FROM THE SIHAILONGWAN MAAR,NORTHEASTERN CHINA

    Institute of Scientific and Technical Information of China (English)

    储国强; 顾兆炎; 许冰; 刘强; 孙青; 汉景泰; 刘嘉麒

    2005-01-01

    对东北四海龙湾玛珥湖SHL-F6孔纹层沉积物的137Cs放射性测量表明:137Cs比活度的最大值出现在5.5cm处,对应于1963年世界原子弹试爆高峰期.纹层计年表明0~6cm共有35个纹层层偶.从7.5cm到6.5cm,137Cs比活度从2.56±0.09dpm/g急剧增加到18.68±0.17dpm/g,可能6.5cm对应于1954年.通过测量226Ra子核214Pb和214Bi(能量为295keV,352keV和609keV)放射的光子数获得226Ra比活度数据,然后求得过剩210Pb比活度(210Pbuns). 210Pbuns比活度随深度增加而呈指数衰减,其异常波动可能与人类活动以及沉积速率变化有关,例如5.5cm处210Pb比活度较高,与137Cs的峰值对应,这可能与1963年前后人工核实验的高峰有关,因为核试验不仅产生137Cs,而且可以产生208Pb和210Pb; 4.5cm处210Pb比活度较低,而226Ra较高,可能与人类活动加剧,导致沉积速率增加有关.根据210PbunsCRS模式, SHL-F6孔0~19cm的平均沉积速率为20mg/cm2 · a,或约为0.11cm/a.210Pb测年数据与137Cs时标及纹层计年均有很好的一致性.四海龙湾玛珥湖发育的纹层为年纹层,可以建立高分辨率时间序列.

  6. "Als het bedrijf er maar niet teveel last van heeft" : de invloed van het ouderschapsbeleid en de ouderschapscultuur van supermarkten en boekhandels op de combinatieproblemen van mannelijke en vrouwelijke werknemers met jonge kinderen

    NARCIS (Netherlands)

    Veenis, E.

    2001-01-01

    What impact do businesses have on the efforts of parents with young children who combine work and family, and what factors within the business play a role in this? This was the principal question in this comparative case study of two retailers, a large supermarket chain and a small group of booksell

  7. Nieuwe uitbreidingen Center for Biobased Economy in het verschiet: 'Komende twee jaar starten met alle nieuwe vakken en minors'

    NARCIS (Netherlands)

    Wijffels, R.H.

    2013-01-01

    Het Nederlandse onderwijslandschap heeft haar keuze gemaakt. De biobased economy vergt geen nieuwe opleidingen, maar de integratie van biobased bouwstenen in bestaande opleidingen. Op die manier worden geen generalisten, maar biobased specialisten gecreëerd. Onder de vlag van het Center for Biobased

  8. Diminished capability to recognize the optimal temperature for sleep initiation may contribute to poor sleep in elderly people

    NARCIS (Netherlands)

    Raymann, R.J.E.M.; Someren, E.J.W. Van

    2008-01-01

    Milde huidverwarming verhoogt de slaperigheid en slaapdruk niet alleen bij volwassenen maar ook bij ouderen, maar ouderen met slaapproblemen kunnen deze milde veranderingen in huidtemperatuur niet of nauwelijks waarnemen, waardoor het buiten de experimentele setting/in het dagelijks leven dus

  9. Usability evaluation of healthcare information systems: comparison of methods and classification of usability problems

    NARCIS (Netherlands)

    Khajouei, R.

    2011-01-01

    In ziekenhuizen wordt steeds meer gebruik gemaakt van informatiesystemen, maar de usability laat vaak te wensen over. Reza Khajouei testte twee methodes om de usability te beoordelen. Hij constateert dat beide methoden ongeveer evenveel, maar verschillende problemen aan het licht brengen. Uit een en

  10. Mathematical modelling in Swirling flows; a Hamiltonian perspective

    NARCIS (Netherlands)

    Fledderus, E.R.

    1997-01-01

    De aanwezigheid van wervels is een essentieel onderdeel in veel industri¨ele processen zoalsmenging, scheiding, stabilisatie, etc. Maar het onbedoeld optreden van wervelingen, al dan niet door toedoen van de mens, kan ook grote schade aanrichten; tornado's zijn waarschijnlijk het meest bekend, maar

  11. Een punt voor gym!? : beoordelen in de lichamelijke opvoeding

    NARCIS (Netherlands)

    Borghouts, Lars; Dokkum, Gertjan van; Slingerland, Menno

    2013-01-01

    Het is logisch dat je een cijfer krijgt voor wiskunde, Engels, Nederlands, scheikunde. Maar hoe zit het eigenlijk met het vak Lichamelijke Opvoeding? Leerlingen, ouders, de school, iedereen verwacht een 'punt voor gym' op het rapport. Maar het zal niet gauw voorkomen dat een leerling die op de cogni

  12. Productinnovatie voor nichemarkten

    NARCIS (Netherlands)

    Veggel, van R.J.F.M.

    2008-01-01

    Voor het uitbreiden van de afzetmarkt en het aanboren van nieuwe markten zijn productinnovaties nodig. Maar wat voor productinnovaties vallen in de smaak bij consumenten en niet te vergeten bij de retail? En wat doe je als je maar weinig budget hebt voor innovatie en marketing? Ziehier de insteek va

  13. Spuitmachine-wasprogramma's doen wat ze moeten doen : Vergelijking door PPO Vredepeel

    NARCIS (Netherlands)

    Hoenderken, J.; Zevenbergen, G.J.; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente

    2009-01-01

    De veldspuit moet je elke dag of bij verandering van middel reinigen. Dat kan met de hand, maar halfautomatische en automatische spoelsystemen sparen tijd. Alle wasprogramma¿s krijgen de spuit schoon, maar er zijn verschillen, ondervonden LandbouwMechanisatie, PPO Vredepeel en DLV Plant tijdens een

  14. Ongelijkheid in Nederland

    NARCIS (Netherlands)

    Salverda, W.

    2014-01-01

    Een goede vergelijking van de ongelijkheid in Nederland met de uitkomsten van Piketty’s onderzoek is niet goed mogelijk, al was het maar omdat onze cijfers over vermogens niet verder teruggaan dan de jaren negentig. Maar duidelijk is dat de Nederlandse vermogensongelijkheid internationaal gezien gro

  15. Een punt voor gym!?

    NARCIS (Netherlands)

    drs Menno Slingerland; dr. Lars B. Borghouts; Gertjan van Dokkum

    2013-01-01

    Het is logisch dat je een cijfer krijgt voor wiskunde, Engels, Nederlands, scheikunde. Maar hoe zit het eigenlijk met het vak Lichamelijke Opvoeding? Leerlingen, ouders, de school, iedereen verwacht een 'punt voor gym' op het rapport. Maar het zal niet gauw voorkomen dat een leerling die op de cogni

  16. Hoeveel

    NARCIS (Netherlands)

    Jansen, J.J.G.

    2005-01-01

    Betrouwbare getallen over de aantallen moslims in Nederland bestaan niet. Rond de jaarwisseling 2004/2005 werd algemeen uitgegaan van een miljoen, maar daar moet er in ieder geval één van worden afgetrokken: Ayaan Hirsi Ali. Dan zijn het er nog steeds 999.999, maar ik heb heel wat vrienden en

  17. Veerkrachtige innovatieteams: onderzoek van Peter Oeij

    NARCIS (Netherlands)

    Oosthoek, E.

    2017-01-01

    In de l&d-werkpraktijk is innovatie niet meer weg te denken. Hardop zeggen we dat vernieuwing het nieuwe normaal is, maar zie dat maar eens constructief te maken. Door verschillende belangen is het vaak lastig manoeuvreren. Een theoretische onderbouwing en best practices van andere innovatieve organ

  18. Drie nationale cyber security strategieën vergeleken

    NARCIS (Netherlands)

    Luiijf, H.A.M.

    2011-01-01

    Onafhankelijk van elkaar brachten Frankrijk, Duitsland en Nederland hun nationale cyber security strategieën vrijwel tegelijk uit. De strategieën hebben overeenkomsten, maar tonen ook grote verschillen. De drie landen onderkennen een urgente noodzaak om cyber security aan te pakken, maar hebben ande

  19. Mathematical modelling in swirling flows: a Hamiltonian perspective

    NARCIS (Netherlands)

    Fledderus, Erik Richard

    1997-01-01

    De aanwezigheid van wervels is een essentieel onderdeel in veel industri¨ele processen zoalsmenging, scheiding, stabilisatie, etc. Maar het onbedoeld optreden van wervelingen, al dan niet door toedoen van de mens, kan ook grote schade aanrichten; tornado's zijn waarschijnlijk het meest bekend, maar

  20. Quantumcomputers: hoe en wanneer?

    NARCIS (Netherlands)

    Hanson, Ronald; Zwanenburg, Floris

    2014-01-01

    Door gebruik te maken van superpositie en verstrengeling kunnen quantumcomputers en quantumnetwerken taken verrichten die met de huidige ICT gebaseerd op ‘klassieke’ bits niet mogelijk zijn. Maar hoe maak je eigenlijk een quantumcomputer? Is er maar één manier? En wat zijn de fysische bouwstenen? In

  1. Bijblijven op je vakgebied nieuwe stijl! : Awareness tools voor e-journals

    NARCIS (Netherlands)

    Bijker, Alie; van den Brekel, Guus

    2013-01-01

    "Ik probeer regelmatig een aantal favoriete tijdschriften via email alerts te lezen, maar blijf het omslachtig vinden en mijn mailbox raakt maar voller en voller!" "Ik vind het lastig om op mijn tablet of via de email vanaf thuis toegang te krijgen tot de full text van artikelen" Hoe blijf je op de

  2. Capacitive bioanodes for electricity storage in Microbial Fuel Cells

    NARCIS (Netherlands)

    Deeke, A.

    2014-01-01

    Denkend aan het opraken van de fossiele brandstoffen, wordt de noodzaak om naar hernieuwbare alternatieven te kijken alleen maar groter. Zon, wind, water en biomassa zijn al hernieuwbare bronnen die actueel gebruikt worden. Maar voor zonne-, wind- en waterenergie beperkt die discontinue aanwezigheid

  3. Bijblijven op je vakgebied nieuwe stijl! : Awareness tools voor e-journals

    NARCIS (Netherlands)

    Bijker, Alie; van den Brekel, Guus

    2013-01-01

    "Ik probeer regelmatig een aantal favoriete tijdschriften via email alerts te lezen, maar blijf het omslachtig vinden en mijn mailbox raakt maar voller en voller!" "Ik vind het lastig om op mijn tablet of via de email vanaf thuis toegang te krijgen tot de full text van artikelen" Hoe blijf je op de

  4. Drie nationale cyber security strategieën vergeleken

    NARCIS (Netherlands)

    Luiijf, H.A.M.

    2011-01-01

    Onafhankelijk van elkaar brachten Frankrijk, Duitsland en Nederland hun nationale cyber security strategieën vrijwel tegelijk uit. De strategieën hebben overeenkomsten, maar tonen ook grote verschillen. De drie landen onderkennen een urgente noodzaak om cyber security aan te pakken, maar hebben

  5. Belasting betalen met kunst. Openheid in het belang van de democratische rechtsstaat en het openbaar kunstbezit

    NARCIS (Netherlands)

    S.J.C. Hemels (Sigrid)

    2011-01-01

    textabstractHet kan in Nederland al bijna 15 jaar, maar slechts weinig mensen zijn ervan op de hoogte: belasting betalen met kunst. Het gebrek aan openheid bemoeilijkt niet alleen de democratische controle op de rechtvaardigheid en efficiëntie van de belastingheffing, maar frustreert ook de effectiv

  6. Lichtintensiteit en -kleur beïnvloeden ontwikkeling ziekten en plagen

    NARCIS (Netherlands)

    Hofland-Zijlstra, J.D.; Heuvelink, E.; Kierkels, T.

    2013-01-01

    Met het oprukken van LED-lampen nemen de sturingsmogelijkheden toe. En tevens de complexiteit van het telen. Want licht beïnvloedt niet alleen de planten, maar ook hun ziekten en plagen. Lange tijd was dat een blinde vlek, zowel binnen het onderzoek als de praktijk. Maar de inzichten groeien.

  7. Wat is goede compost?

    NARCIS (Netherlands)

    Willekens, K.; Janmaat, L.

    2014-01-01

    Compost wordt voor meerdere doelen ingezet. Als meststof, maar ook om de organische stofbalans op peil te houden. Maar compost heeft nog meer voordelen. Zo worden aan compost ziektewerende eigenschappen toegekend. Het doel van compostgebruik bepaalt voor een groot deel welke prijs er voor wordt beta

  8. Never waste a good crisis: De maatschappelijke waarde van pop-up retail

    NARCIS (Netherlands)

    Loggers, B.; Kooijman, D.C.

    2014-01-01

    Pop-up retail is tijdelijke winkelverkoop. Pop-up retail is hip en hot, maar evengoed een crisisverschijnsel. Het kan alleen maar bestaan als er leegstand is en die leegstand is er tot verdriet van vastgoedbeleggers, ontwikkelaars, gemeenten en retailers de laatste jaren in toenemende mate.

  9. Fokken op kale koppen : hoornloosheid nu nog vooral gezien als ‘leuke bijkomstigheid’

    NARCIS (Netherlands)

    Drie, van I.

    2008-01-01

    Welzijnsonvriendelijke ingrepen bij dieren stuiten op steeds meer maatschappelijke weerstand. Dat geldt voor het castreren van biggen, maar ook voor het onthoornen van dieren. Fokken op hoornloosheid geldt als mogelijke oplossing. Een aantal hoornloze stieren is beschikbaar, maar de animo onder veeh

  10. Phreatomagmatic and water-influenced Strombolian eruptions of a small-volume parasitic cone complex on the southern ringplain of Mt. Ruapehu, New Zealand: Facies architecture and eruption mechanisms of the Ohakune Volcanic Complex controlled by an unstable fissure eruption

    Science.gov (United States)

    Kósik, S.; Németh, K.; Kereszturi, G.; Procter, J. N.; Zellmer, G. F.; Geshi, N.

    2016-11-01

    The Ohakune Volcanic Complex is a late Pleistocene tuff ring - scoria/spatter cone complex located south of Ruapehu volcano. This small-volume volcano consists of an outer E-W elongated compound tuff ring edifice, three inner scoria-spatter cones and further volcanic depressions, located on the Ohakune Fault. We quantified accurately the variations of the eruptive styles and processes through time by systematic sampling of key stratigraphic marker beds at proximal and distal locations, and the determination of grain size distribution, componentry, density and vesicularity. Using a Digital Terrain Model coupled with stratigraphic data, we also determined the spatial distribution and volume of each identified unit and individual edifices within the Ohakune Volcanic Complex. Activity began with a shallow phreatomagmatic phase characterized by an almost continuous generation of a low eruptive column, accompanied by wet pyroclastic density currents, together with the ejection of juvenile fragments and accidental lithics from the surrounding country rocks. Subsequent activity was dominated by a variety of Strombolian eruptions exhibiting differing intensities that were at times disrupted by phreatic blasts or phreatomagmatic explosions due to the interaction with external water and/or sudden changes in magma discharge rate. At least three major vent-shifting events occurred during the eruption, which is demonstrated by the truncation of the initial tuff ring and the infilling of the truncated area by several coarse grained surge units. Our study indicates that approx. 12 × 106 m3 DRE magma erupted within maximum 2.5 to 5 months through multiple vents. The erupted magma ascended from a depth of 16-18 km, and reached the surface within approximately 50 h. Alternating eruption styles, frequent vent-shifting and a variety of emplacement mechanisms inferred from the deposits of the Ohakune Volcanic Complex demonstrate the unpredictable nature of small-volume volcanism

  11. An unusually energetic basaltic phreatomagmatic eruption: Using deposit characteristics to constrain dilute pyroclastic density current dynamics

    Science.gov (United States)

    Brand, Brittany D.; Clarke, Amanda B.

    2012-10-01

    Multiple, highly erosive base surges of the Table Rock Complex tuff ring (TRC2), Oregon, produced dune-bedded deposits with crest to crest bedform wavelengths up to 200 m, which are amongst the largest ever recognized in the deposits of pyroclastic density currents. Here we use bedform wavelength, surmounted obstacles, and a large chute-and-pool feature to estimate near-source velocities (118-233 m s- 1), lower-bound velocities at radial distances of 1.6, 2 and 4.7 km from source (34, 29 and 20 m s- 1, respectively), and corresponding column collapse heights (up to 2.8 km). This paper represents one of the few studies that attempt to quantify flow characteristics, such as emplacement velocities at different distances from source, eruption column collapse height, and eruptive energy, based on deposit characteristics.

  12. Environmental and Compositional Controls on the Texture and Composition of Palagonitized Hyaloclastites

    Science.gov (United States)

    Pauly, B. D.; Schiffman, P.; Zierenberg, R. A.; Yin, Q.

    2008-12-01

    Palagonitization is a widespread geochemical process in which sideromelane is converted to hydrous alteration products (palagonite and a variety of authigenic minerals) in subaqueous environments that produce volcanic glass. Recognizing that an 'aging' process may influence the textural and compositional properties of palagonite over time, we have been investigating the direct effects of specific environmental conditions (e.g. glass and fluid composition, fluid/rock ratio) on palagonite formation. For this study, hyaloclastite samples inferred to have palagonitized in relatively low fluid/rock ("closed") environments (submarine volcano flanks, submarine volcaniclastic basins) as well as from relatively high fluid/rock ("open") environments (tuff cones, subaqueous and subglacial eruption sites) were subjected to petrographic, electron microprobe, and LA-ICP-MS analysis. Palagonite rind textures are broadly consistent at each sampled site, but there is a wide range of textural variation between the sites. Rind thickness in all our samples varies from 0.05 to 1.0 mm, and the thicker rinds are generally from localities where it is believed that the aging of palagonite glass has occurred over a relatively long time. Authigenic zeolites are much more common in samples palagonitized in lower fluid/rock environments. Inferred water content of palagonite in our samples varies from 17 to 37 weight percent and appears to be highest from tuff cones, intermediate from subaqueous eruption sites, and lowest from submarine volcaniclastic basins. In submarine volcaniclastic sandstones sampled offshore of Kilauea and Mauna Loa volcanoes, palagonite rind compositions from adjacent grains of alkalic and tholeiitic sideromelane are distinguishable and reflect the original glass composition. Palagonite REE patterns parallel those of adjacent sideromelane, but the REE concentrations are higher in the palagonite and increase systematically towards the outermost palagonitized rim

  13. Petrology and geochemistry of the San Félix-San Ambrosio islands, Eastern Pacific

    Science.gov (United States)

    Cooper Percker, Oliver; Lara, Luis E.

    2015-04-01

    The San Félix-San Ambrosio (SF-SA) islands, Eastern Pacific, are fragments of two volcanic sequences 20 km apart. Both represent the top of an eroded large shield-volcano which rises over the Nazca Plate. Here, new geochemical and 40Ar/39Ar geochronological data are presented in order to understand magmatic evolution and source features. Two units are recognized on the SF island: (1) the Cerro Amarillo unit (CAU) (190±30 ka) formed by a hyaloclastic-tuff cone and basanitic lavas (Ba/Yb=519; Ba/Zr=2.19; La/Yb=49.88; Nb/Ta=17.96; Nb/Y=3.78; Nb/Zr=0.25) with absent or scarce modal content of plagioclase (20%). The hyaloclastic-tuff cone of the CAU contains aphanitic-trachytic lithic fragments of Na-augite and kaersutite, which correspond to the final product of fractional crystallization of olivine+clinopyroxene+Fe-Ti oxides+apatite±plagioclase from alkaline primitive liquids similar to SF-SA lavas. The geochemical data suggest that the islands represent different evolutive stages of a same volcanic intraplate complex. The alkaline to transitional SA lavas (Ba/Yb=249; Ba/Zr=1.60; La/Yb=24.62; Nb/Ta=16.55; Nb/Y=2.22; Nb/Zr=0.19) would represent the shield stage (ca 2.9 Ma), while the basanitic SF lavas the post-erosional stage (ca 0.2 Ma). Considering the Sr-Nd-Pb isotopic data of the SF-SA lavas, previous works have ruled out a genetic relationship between SF-SA islands and the nearby Nazca Ridge. An heterogeneous mantle plume with mantelic metasomatized recycled lithologies is hypothesized as a possible magmatic source capable of explaining the petrologic differences between the SF-SA islands and between the CAU and PU, in SF island. This research is supported by FONDECYT Project 1141303.

  14. Stratigraphy and eruption ages of deposits at the southeast side of Nishiyama volcano, Hachijo island during the last 2,500 years; Hachijojima, Nishiyama kazan nantoroku ni okeru saikin 2,500 nenkan no funshutsubutsu no sojo to funka nendai

    Energy Technology Data Exchange (ETDEWEB)

    Sugihara, S.; Shimada, S. [Meiji University, Tokyo (Japan)

    1998-10-25

    The Nishiyama volcano of the Hachijo island is a stratovolcano whose volcanic activity started approximately 10,000 years ago. Among the lateral volcanos surrounding the cone-shaped mountain, there is a Kandoyama tuff cone formed by a phreatomagmatic eruption at the southeastern base of the Nishiyama volcano. It is known that Kandoyama`s latest eruption is not older than 4,000 years. In this report, the stratigraphy of eruptive deposits and the types of eruptions involving Nishiyama after Kandoyama formation are clarified. Also, the history of Nishiyama` eruption is discussed, for which a study is made about the stratigraphic relationship between its eruption and the results of {sup 14}C dating or the eruption remainders, corresponding terrestrial episodes recorded in ancient literature usable for eruption dating, etc. The conclusion is summarized below. The eruptive deposits are to be supposedly dated at a period after the completion of caldera aggradation. At the southeastern base of Nishiyama, the eruption of 1605 is to immediately follow the eruption of approximately 1,100 years ago, and no eruption so active as to cause the outflow of lava is noticed therebetween. It is inferred that the Nishiyama volcano erupts once in a period of 300-700 years. 44 refs., 11 figs., 2 tabs.

  15. Amazonian volcanism inside Valles Marineris on Mars

    Science.gov (United States)

    Brož, Petr; Hauber, Ernst; Wray, James J.; Michael, Gregory

    2017-09-01

    The giant trough system of Valles Marineris is one of the most spectacular landforms on Mars, yet its origin is still unclear. Although often referred to as a rift, it also shows some characteristics that are indicative of collapse processes. For decades, one of the major open questions was whether volcanism was active inside the Valles Marineris. Here we present evidence for a volcanic field on the floor of the deepest trough of Valles Marineris, Coprates Chasma. More than 130 individual edifices resemble scoria and tuff cones, and are associated with units that are interpreted as lava flows. Crater counts indicate that the volcanic field was emplaced sometime between ∼0.4 Ga and ∼0.2 Ga. The spatial distribution of the cones displays a control by trough-parallel subsurface structures, suggesting magma ascent in feeder dikes along trough-bounding normal faults. Spectral data reveal an opaline-silica-rich unit associated with at least one of the cones, indicative of hydrothermal processes. Our results point to magma-water interaction, an environment of astrobiological interest, perhaps associated with late-stage activity in the evolution of Valles Marineris, and suggest that the floor of Coprates Chasma is promising target for the in situ exploration of Mars.

  16. Electrical Resistivity Monitoring of an Active Hydrothermal Degassing Area at Solfatara, Phlegrean Fields.

    Science.gov (United States)

    Vandemeulebrouck, J.; Byrdina, S.; Grangeon, J.; Lebourg, T.; Bascou, P.; Mangiacapra, A.

    2015-12-01

    Campi Flegrei caldera (CFc) is an active volcanic complex covering a ~100 km² densely populated area in the western part of Naples (Italy) that is presently showing clear signs of unrest. Solfatara volcano, a tuff cone crater formed ~4000 yrs B.P. ago by phreato-magmatic eruptions represents the main degassing outflow of CFc. Magmatic gases which are exsolved from a ~8 km deep magmatic reservoir mix at 4 km depth with meteoric hydrothermal fluids then reach the surface in the Solfatara area. These hydrothermal and magmatic gases, mainly H2O and CO2, are released through both diffuse degassing structures and fumaroles. In the frame of the MedSuv (Mediterranean Supervolcanoes) FP7 european project , we are performing a time-lapse electrical resistivity monitoring of an active degassing area of Solfatara. Using a 500-m-long cable and 48 electrodes, an electrical resistivity tomography (ERT) is performed on a two-day basis since May 2013. The time-lapse inversion of the ERT gives an image of the temporal variations of resistivity up to 100 m depth that can be compared with the variations of ground deformation, CO2 flux, soil temperature and seismic ambient noise. Resistivity variations can originate from fluid composition, gas ratio and temperature. For example, the abrupt change of resistivity that was observed mid-2014 during a period of uplift and gas flux increase, could be associated with the rise of hydrothermal fluids.

  17. Geologic map of the Paintbrush Canyon Area, Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Dickerson, R.P. [Geological Survey, Denver, CO (United States); Drake, R.M. II [Pacific Western Technologies, Ltd., Lakewood, CO (United States)

    1998-11-01

    This geologic map is produced to support site characterization studies of Yucca Mountain, Nevada, site of a potential nuclear waste storage facility. The area encompassed by this map lies between Yucca Wash and Fortymile Canyon, northeast of Yucca Mountain. It is on the southern flank of the Timber Mountain caldera complex within the southwest Nevada volcanic field. Miocene tuffs and lavas of the Calico Hills Formation, the Paintbrush Group, and the Timber Mountain Group crop out in the area of this map. The source vents of the tuff cones and lava domes commonly are located beneath the thickest deposits of pyroclastic ejecta and lava flows. The rocks within the mapped area have been deformed by north- and northwest-striking, dominantly west-dipping normal faults and a few east-dipping normal faults. Faults commonly are characterized by well developed fault scarps, thick breccia zones, and hanging-wall grabens. Latest movement as preserved by slickensides on west-dipping fault scarps is oblique down towards the southwest. Two of these faults, the Paintbrush Canyon fault and the Bow Ridge fault, are major block-bounding faults here and to the south at Yucca Mountain. Offset of stratigraphic units across faults indicates that faulting occurred throughout the time these volcanic units were deposited.

  18. Moeilijk te sturen met groeilicht: drie belichtingssystemen onderzocht bij paprika

    NARCIS (Netherlands)

    Stijger, H.; Hogendonk, L.

    2005-01-01

    De stuurbaarheid van paprika is moeilijk zonder buitenlicht, maar ook mét groeilicht. De productieverschillen tussen de drie verschillende belichtingssystemen zijn minimaal. Bij het systeem dat de meeste kilo's geeft, de vaste belichting, zijn de kosten het laagst.

  19. Verf en biodiesel uit algen

    NARCIS (Netherlands)

    Mooibroek, H.

    2009-01-01

    Met algen kun je niet alleen biodiesel en groene coatings produceren, maar ook iets doen aan het mestoverschot en de uitstoot van kooldioxide. In Delfzijl zijn kweekvijvers geopend om de technologie hiervoor te ontwikkelen

  20. Nieuwe ontwikkelingsrichtingen voor verpakte groente- en fruitproducten : verpakte groente- en fruitproducten voor nieuwe eetmomenten

    NARCIS (Netherlands)

    Thoden van Velzen, E.U.

    2012-01-01

    De huidige standaardverpakkingen voor vers verwerkte groente- en fruitproducten zijn glas, blik en kartonlaminaat en zakken en vouwkarton voor diepvriesproducten. Deze verpakkingen ondersteunen het thuisgebruik bij het avondeten, maar niet nieuwe eetmomenten als ontbijt, lunch, tussendoortje en eten

  1. Ideaalbeeld freesia op de kop (interview met Frank van der Helm)

    NARCIS (Netherlands)

    Sleegers, J.; Helm, van der F.P.M.

    2012-01-01

    Een onderzoek naar bodemisolatie in freesia heeft niet het bedoelde effect opgeleverd. Maar het heeft wel het ideaalbeeld van de plant op zijn kop gezet. De schraalste planten leverden de mooiste takken op.

  2. Over de relatie tussen P.G.Wodehouse en Georges Mazure

    NARCIS (Netherlands)

    Nieuwenhuizen, Peter I.

    2007-01-01

    Over de werken van de illustrator Georges Mazure in relatie tot de teksten van P.G.Wodehouse. Mazure verwerkte de Wodehouse-uitgave "Leave it to Psmith" tot de krantenstrip "Laat 't maar aan Psmith over!".

  3. Groenbemesters in de strijd tegen gewone wortellesieaaltjes (Pratylenchus penetrans) : eindrapportage

    NARCIS (Netherlands)

    Elberse, I.A.M.; Hoek, H.

    2012-01-01

    Wortellesieaaltjes (Pratylenchus penetrans) kunnen in vele gewassen grote schade aanrichten. Bestrijding kan chemisch gebeuren, met natte grondontsmetting, maar een goed alternatief is het bestrijden door het telen van Tagetes patula (afrikaantjes). Een geslaagde teelt van deze groenbemester zorgt z

  4. Voedingsonderzoek gaat digitaal

    NARCIS (Netherlands)

    Top, J.

    2005-01-01

    Bedrijven en kennisinstellingen in de voedingsmiddelenbranche doen veel onderzoek, maar de resultaten worden vaak onvoldoende benut. Informatietehnologie biedt mogelijkheden voor een beter gebruik van onderzoeksresultaten en voor virtueel onderzoek. Hoe werkt e-science?

  5. Stressgerelateerd verzuim terugdringen met de beslisboom

    NARCIS (Netherlands)

    Pijnappel, B.; Ipkens, T. van; Schelvis, R.M.C.

    2014-01-01

    Medewerkers in het onderwijs ervaren meer variatie, creativiteit en tevredenheid op het werk dan de beroepsbevolking gemiddeld, maar diezelfde medewerkers ervaren ook meer vermoeidheid, stress en burn-out dan medewerkers in andere sectoren, zo blijkt uit onderzoek van TNO.

  6. Dalende rozenscheutboorder verstopt zich

    NARCIS (Netherlands)

    Elberse, I.A.M.

    2004-01-01

    Levenscyclus van Ardis brunniventris en beschrijving van gewasschade in de onderstammenteelt van Rosa canina 'Pfänder'. Onderzoek moet nog worden gedaan naar bestrijden met feromoon. Chemische en biologische bestrijdingsmiddelen zijn nog niet voorhanden, maar worden wel getest

  7. Spordifoorum aitas tekitada ühtsustunnet / Anne Põder

    Index Scriptorium Estoniae

    Põder, Anne, 1973-

    2005-01-01

    Järvamaa spordielust. Vestlusringis osalesid spordinõukogu juht Piret Sapp, spordiliidu tegevjuht Piret Maaring, treenerid Villi Vantsi, Janno Viilup, Rein Valdru, Leonhard Soom ja Järva Teataja spordireporter Anne Põder

  8. Rapport over een inventarisatie van- en een studie over de entomofauna van het C.R.M. reservaat Broekhuizen

    NARCIS (Netherlands)

    Peerdeman, M.P.

    1976-01-01

    Inventarisatie van het terrein rondom het kasteel te Broekhuizen/Leersum. De inventarisatie werd hoofdzakelijk gericht op de entomofauna, maar in dit rapport zijn ook enkele gegevens over andere diergroepen opgenomen.

  9. Techniek moet rijtaak ondersteunen : interview met Fred Wegman, directeur SWOV, over verkeersveiligheid.

    NARCIS (Netherlands)

    Ohm, R.

    2010-01-01

    Het gaat nog steeds goed, maar het kan altijd beter. Helaas is de problematiek ingewikkelder geworden en zijn er geen snelle oplossingen met veel effect meer voorhanden. Daarom moet het karakter van de aanpak van verkeersonveiligheid veranderen. (Author/publisher)

  10. De jonge consument

    NARCIS (Netherlands)

    Buijzen, M.A.; Rozendaal, E.

    2012-01-01

    Kinderen vormen een steeds aantrekkelijkere doelgroep voor marketeers, adverteerders en voorlichters. Maar behalve een aantrekkelijke doelgroep is het ook een bijzondere: kinderen zijn immers nog in ontwikkeling en hebben daardoor specifieke kenmerken en gevoeligheden. Bij het benaderen van de jonge

  11. Het nieuwe meten

    NARCIS (Netherlands)

    Ramaker, R.; Khoury, C.K.

    2015-01-01

    Al decennialang wordt wetenschappelijke kwaliteit en invloed op dezelfde manier gemeten. Maar deugt die methode nog wel in een wereld die door digitalisering en social media ingrijpend is veranderd? Altmetrics biedt een alternatief.

  12. Acute giftigheid en risico's voor kinderen actueel

    NARCIS (Netherlands)

    Kloet, D.

    2000-01-01

    Tijdens de vergaderingen van 1 tot en met 8 mei in Den Haag vormde de acue giftigheid en risico's voor kinderen een belangrijk onderwerp. Vooralsnog komen er geen strengere normen maar de berekeningsmethode voor acute giftigheid wordt verfijnd

  13. Kosten mastitis onderschat: Hoogste kostenpost bij mastitis is melkproductieverlies

    NARCIS (Netherlands)

    Huijps, K.; Lam, T.J.G.M.; Hogeveen, H.

    2007-01-01

    Mastitis kost geld. Maar hoeveel? Beduidend meer dan melkveehouders denken, zo blijkt uit recent onderzoek van het Uiergezondheidscentrum Nederland en de faculteit Diergeneeskunde onder 64 veehouders. Vooral het productieverlies bij subklinische mastitis kost veel euro’s

  14. Landbouw in perspectief van ruimtelijke ordening

    NARCIS (Netherlands)

    Ploeg, van der B.

    2001-01-01

    De Vijfde Nota Ruimtelijke Ordening is eindelijk uitgekomen. Hierin lijkt niet de landbouweconomie het zwaarst te tellen, maar de invloed van de landbouw op de natuur en de leefomgeving van burgers in een stedelijk land.

  15. Mineralenbalans op verschillende schapenbedrijven

    NARCIS (Netherlands)

    Boer, de J.; Bodegraven, van D.

    1994-01-01

    Uit berekeningen blijkt dat naarmate de schapenhouderij intensiever wordt, ook het overschot op de mineralenbalans toeneemt. Jaarrondproduktie heeft het hoogste overschot aan mineralen, maar daarnaast ook het hoogste saldo.

  16. Diagnosis and Treatment of Unconjugated Hyperbilirubinemia

    NARCIS (Netherlands)

    Schreuder, Andrea Bertilde

    2014-01-01

    Bilirubine is een geel afbraakproduct van heem met tegenstrijdige eigenschappen. In lage concentraties is (ongeconjugeerd) bilirubine een antioxidant, maar in hoge concentraties is het zeer schadelijk voor onze hersencellen. Ophoping van (ongeconjugeerd) bilirubine in ons lichaam kan leiden tot perm

  17. Ontwikkeling in groepshuisvesting voor dragende zeugen

    NARCIS (Netherlands)

    Hoste, R.

    2008-01-01

    Vanaf 2013 moeten alle dragende zeugen in Nederland in groepshuisvesting worden gehouden. Het omschakelingsproces is al enige jaren aan de gang, maar veel bedrijven moeten de komende jaren de stap nog maken

  18. Legaliteit en legitimiteit

    NARCIS (Netherlands)

    Gribnau, J.L.M.

    2001-01-01

    Door een aantal factoren is het gewicht van rechtsbeginselen toegenomen. De wetgever wil steeds meer de maatschappelijke ontwikkelingen sturen (modificatie overlopend in instrumentalisme), maar moet de formulering van de norm in concreto vaak aan het bestuur overlaten. De bestuurlijke rechtsvorming

  19. Marketing Planning en Strategische Beleidsvorming bij Nederlandse Bedrijven

    NARCIS (Netherlands)

    B. Wierenga (Berend); J.B. Vollering; R. Amsterdam; C.J. Poederbach

    1986-01-01

    textabstractMarketing-management en strategische beleidsvorming zijn twee belangrijke aandachtsvelden bij de bestudering van ondernemingen en andere organisaties. Hoewel beide gebieden duidelijk van elkaar te onderscheiden zijn, kan een scheiding tussen deze twee voor een onderneming alleen maar des

  20. Kroniek van de intellectuele eigendom

    NARCIS (Netherlands)

    Visser, D.J.G.

    2015-01-01

    Het online doorverkopen en uitlenen van e-books is omstreden. De thuiskopieheffing blijft een kostbaar hoofdpijndossier. Een parodie vereist een humoristische bedoeling. Onpersoonlijke geschriften en verweesde werken zijn niet meer beschermd. Een stoel is geen merk, maar een winkelinrichting

  1. Kosten mastitis onderschat: Hoogste kostenpost bij mastitis is melkproductieverlies

    NARCIS (Netherlands)

    Huijps, K.; Lam, T.J.G.M.; Hogeveen, H.

    2007-01-01

    Mastitis kost geld. Maar hoeveel? Beduidend meer dan melkveehouders denken, zo blijkt uit recent onderzoek van het Uiergezondheidscentrum Nederland en de faculteit Diergeneeskunde onder 64 veehouders. Vooral het productieverlies bij subklinische mastitis kost veel euro’s

  2. Literatuuronderzoek naar gegevens betreffende de betekenis van een aantal verwekkers van zoonosen in verband met de vleesconsumptie. VI: Yersinia enterocolitica

    NARCIS (Netherlands)

    Bos; J.M.; Engel; H.W.B.; Groothuis; D.G.; Knapen; F.van; Oosterom; J.; Weiss; J.W.

    1985-01-01

    Yersinia enterocolitica kan bij de mens aanleiding geven tot verschillende ziektebeelden. Het meest wordt de acute enterocolitis beschreven, vooral bij zeer jonge kinderen, maar daarnaast zijn ook de acute mesenteriale lymfadenitis en terminale ileitis (pseudoappendicitis) bekend. Dragerschap zo

  3. Snijmais of krachtvoer bijvoedering naast gras in het rantsoen voor hoogproduktief melkvee = Maize silage or concentrates as supplements in a grass based diet for high yielding dairy cows

    NARCIS (Netherlands)

    Valk, H.; Klein Poelhuis, H.W.; Wentink, H.J.

    1990-01-01

    Voederproeven, waarbij het niet draait om een optimaal melkproduktieresultaat, maar om de vergelijking tussen diverse bijvoederingsmiddelen voor wat betreft het effect op de N-benutting en N-uitscheiding bij dezelfde VEM-opname

  4. Palmzaadkever opsporen met lichtval en alcohol

    NARCIS (Netherlands)

    Bloemhard, C.M.J.

    2006-01-01

    De palmzaadkever houdt er een verborgen levenswijze op na. Met een lichtval zijn de volwassenen, vliegende vrouwtjes goed te vangen. Tijdige signalering verbetert de bestrijding, maar vooral schoon uitgangsmateriaal importeren verlaagt de infectiedruk

  5. Verba volant, scripta manent / Milvi Tedremaa

    Index Scriptorium Estoniae

    Tedremaa, Milvi, 1937-2012

    1999-01-01

    Rets. rmt.: Meie õppisime raamatukogundust Tartu Ülikoolis / koost. Maare Kümnik, Kaja Noodla. Tartu, 1998. Vastukaja: Peep, Laine. Mitte ainult Milvi Tedremaale // Raamatukogu (1999) nr. 4, lk. 44

  6. Dairy Campus in Leeuwarden krijgt vorm

    NARCIS (Netherlands)

    Koning, de C.J.A.M.; Rotgers, G.

    2011-01-01

    Dairy Campus begint vorm te krijgen. Nog niet in gemetselde bouwstenen, maar in projecten en op papier. Sinds maart 2011 heeft dit nieuwe melkvee-innovatiecentrum van Wageningen Universiteit en Research Center een manager: Kees de Koning.

  7. Rondom rotondes : onderzoek naar markeringen en bewegwijzering bij tweestrooksrotondes

    NARCIS (Netherlands)

    Knabben, E.H.M.; Martens, M.H.

    2001-01-01

    Rotondes duiken in steeds meer varianten op. Vooral de nieuwe tweestrooksrotondes met gescheiden rijstroken vragen nogal wat van de weggebruiker. Wegbeheerders proberen met borden en pijlen de bestuurders een handje te helpen. Maar heipen ze echt?

  8. Comprehensive competence-based vocational education : the development and use of a curriculum analysis and improvement model

    NARCIS (Netherlands)

    Wesselink, R.

    2010-01-01

    Competentiegericht beroepsonderwijs is zowel nationaal als internationaal een populair concept. Een eenduidige definitie ontbrak echter, maar is wel noodzakelijk als uitspraken moeten worden gedaan over de effectiviteit er van. Door middel van het vaststellen van acht principes, die zijn uitgewerkt

  9. Pompidou keskus on vääriline partner / Reet Varblane

    Index Scriptorium Estoniae

    Varblane, Reet, 1952-

    2008-01-01

    Pariisi Pompidou keskuse näitus "Tegelikkuse sabotaazh. Sürrealism Euroopa fotokunstis 1922-1947" Kumu Kunstimuuseumis. Kuraator Quentin Bajac. Kuulsamatest kunstnikest on näitusel esindatud Man Ray, Dora Maar, Brassai, Eli Lotar, Claude Cahun

  10. Glasgroentesector staat voor grote uitdaging

    NARCIS (Netherlands)

    Wijnands, J.H.M.; Poot, E.H.

    2005-01-01

    De glasgroentesector kan internationaal voorop blijven lopen, maar alléén met een forse inspanning volgens LEI en PPO. Samenwerking is het sleutelwoord om alle uitdagingen te overwinnen en een juiste strategie voor de toekomst te ontwikkelen

  11. Concurrentie op Friedmans platte aarde: Online marktplaatsen als voorbode van globale concurrentie

    NARCIS (Netherlands)

    Beerepoot, N.

    2012-01-01

    Online markplaatsen waar iedereen zijn digitaal leverbare diensten kan aanbieden, confronteren westerse freelancers direct met concurrentie uit ontwikkelingslanden. Maar hoger opgeleiden in niet-westerse regio’s krijgen zo nieuwe kansen.

  12. Diergeneesmiddelen en natuurlijke hormonen in oppervlaktewater van gebieden met intensieve veehouderij

    NARCIS (Netherlands)

    Montforts MHMM; Rijs GBJ; Staeb JA; Schmitt H; SEC

    2008-01-01

    Natuurlijke hormonen komen voor in kleine oppervlaktewateren in het landelijk gebied, maar effecten op de lokale brasempopulatie werden niet gevonden. Daarnaast zijn antibiotica aangetoond, en werd een grotere verscheidenheid aan resistentiegenen in bacterien tegen antibiotica aangetoond, dan in

  13. Ook een honingbij ontgift zich : drugkoeriers en narcoticabrigades actief in de bij

    NARCIS (Netherlands)

    Scheer, van der H.; Blacquiere, T.

    2014-01-01

    Honingbijen komen bij het foerageren met allerlei stoffen in aanraking, ook met insecticiden.Maar ze zijn ook in staat tot ontgiften. Dit artikel geeft uitleg over het mechanisme daarvan enover recent onderzoek op dit gebied aan bijen.

  14. De vrijheid van meningsuiting en hate speech: een rechtsvergelijking met de VS

    NARCIS (Netherlands)

    van Vugt, Eva

    2016-01-01

    De vrijheid van meningsuiting is een groot goed in een democratische samenleving maar kan onder bepaalde voorwaarden ingeperkt worden. Haatuitingen genieten bijvoorbeeld in veel westerse democratieën geen (volledige) bescherming. De VS vormt een uitzondering in dit opzicht

  15. Het gebruik van voedingssupplementen en sportvoeding door meer en minder actieve Nederlanders – Een inventarisatie op basis van het Nationaal Sport Onderzoek

    NARCIS (Netherlands)

    Wardenaar, F.C.; Geelen, I.J.M.; Dool, van den R.; Witkamp, R.F.; Mensink, M.R.

    2014-01-01

    Achtergrond - Gegevens over het gebruik van sportvoedingsproducten en voedingssupplementen onder de algemene bevolking zijn zeer beperkt en onderling moeilijk vergelijkbaar. Het gebruik van voedingssupplementen onder (top)sporters is goed gedocumenteerd, maar veel producten worden waarschijnlijk ook

  16. Is met Predictive Policing de heilige graal gevonden?

    NARCIS (Netherlands)

    Smit, S.K.; Vries, A. de

    2016-01-01

    Het politiewerk gaat ingrijpend veranderen door de invoering van Predictive Policing. Door verfijnde algoritmen los te laten op big data over eerdere incidenten – en die hoeveelheid gegevens neemt alleen maar toe – kan de politie straks misdaden voorspellen.

  17. Schoon blijven in een modderbad

    NARCIS (Netherlands)

    Wagemakers, J.

    2015-01-01

    Extremistisch, streng, en zelfs gevaarlijk: dat is hoe veel mensen salafisten zien. Maar voor de aanhangers van deze stroming is het simpelweg de meest zuivere vorm van de islam. Hoe staan salafi’s in het leven?

  18. Flexible filter feeders : The gelatinous zooplankton community in the Netherlands after the invasion of the ctenophore Mnemiopsis leidyi

    NARCIS (Netherlands)

    van Walraven, Lodewijk

    2016-01-01

    Of kwallen wereldwijd steeds meer voorkomen is een onderwerp van discussie, maar ze zorgen steeds vaker voor problemen zoals verstopte visnetten, verstopte koelwaterinlaten of wegblijvende toeristen. In Nederlandse kustwateren zorgde de vondst van de invasieve Amerikaanse ribkwal Mnemiopsis leidyi v

  19. Comparison of methods for enumeration of total coliforms and Escherichia coli in water samples in the Netherlands

    NARCIS (Netherlands)

    Schets FM; Nobel PJ; Strating S; Mooijman KA; Engels GB; Brouwer A; MGB

    2001-01-01

    De nieuwe Europese Drinkwater Richtlijn (december 1998) definieert een referentiemethode voor de schatting van de concentratie bacterien van de coligroep en Escherichia coli in drinkwater. Laboratoria mogen andere methoden gebruiken, maar moeten aantonen dat de verkregen resultaten minstens zo betr

  20. Flexible filter feeders : The gelatinous zooplankton community in the Netherlands after the invasion of the ctenophore Mnemiopsis leidyi

    NARCIS (Netherlands)

    van Walraven, Lodewijk

    2016-01-01

    Of kwallen wereldwijd steeds meer voorkomen is een onderwerp van discussie, maar ze zorgen steeds vaker voor problemen zoals verstopte visnetten, verstopte koelwaterinlaten of wegblijvende toeristen. In Nederlandse kustwateren zorgde de vondst van de invasieve Amerikaanse ribkwal Mnemiopsis leidyi v

  1. Qualitative research in nursing - Advancing the humanistic imperative

    Directory of Open Access Journals (Sweden)

    A Botes

    1996-01-01

    Full Text Available Die boek spreek nie net die filosofiese dimentsies van kwalitatiewe navorsing aan nie, maar ook die metodologiese aspekte. *Please note: This is a reduced version of the abstract. Please refer to PDF for full text.

  2. Leibniz, metafysicus van het atoomtijdperk

    NARCIS (Netherlands)

    Romeijn, J.-W.

    2008-01-01

    Wat heeft de rekenkunde met de metafysica van doen? Massimo Mugnai laat ons in “Leibniz, Filosoof en Mathematicus” kennismaken met Leibniz als grondlegger van de logica. Maar dat is lang niet alles.

  3. Chemische onkruidbestrijding op verhardingen : zeven machines getest

    NARCIS (Netherlands)

    Kempenaar, C.

    2009-01-01

    Met onkruidstrijkers, sensorgestuurde technieken en schijfvernevelaars mag je chemisch onkruid bestrijden op verhardingen. Maar wat is het verbruik, de selectiviteit en effectiviteit van deze technieken? Een onderzoek geeft inzicht.

  4. Burgers tegen Plasterk: het Nederlandse staartje van de Snowden-saga

    NARCIS (Netherlands)

    van Daalen, O.

    2015-01-01

    De Snowden-onthullingen haalden niet alleen wereldwijd de media en het parlementair debat. Ze leidden zelfs tot een Nederlandse rechtszaak over communicatieprivacy. Een principiële rechtszaak over burgerrechtenactivisme, surveillance en politieke intrige, met een verrassende, maar ook

  5. 'Verleid consumenten tot gezond gedrag'

    NARCIS (Netherlands)

    Trijp, van J.C.M.

    2008-01-01

    Dat de gemiddelde Nederlander niet gezond leeft, dat is ondertussen bekend. Maar wat doe je eraan? Met marketing kom je een heel eind, weet Hans van Trijp, hoogleraar bij de Wageningse leerstoelgroep Marktkunde en consumentengedrag

  6. Generating incremental attribute evaluators

    NARCIS (Netherlands)

    Pennings, Maarten Christiaan

    2001-01-01

    In onze maatschappij wordt tegenwoordig veel met software, dat wil zeggen com- puterprogramma's, gewerkt. Denk daarbij niet alleen aan tekstverwerkers, maar ook aan software in geldautomaten, videorecorders en het administratiesysteem van de scus. Software moet geschreven worden. Programmeurs schrij

  7. Lymphotropic Herpesvirus infection and malignant lymphoma, immunological aspects of cytomegalovirus and Epstein- Barr virus infections

    NARCIS (Netherlands)

    Napel, Christianus Hubertus Henricus ten

    1979-01-01

    In de voorgaande hoofdstukken van dit proefschrift werd de oorspronkelijke chronologische volgorde van het onderzoek aangehouden. Maar in dit deel wordt hiervan afgeweken en zullen de resultaten worden samengevat en besproken volgens onderstaande indeling: 1. Cytomegalovirus( CMV)-specifieke immuunr

  8. Bylaag 3 tot „Koer&’’, April en Junie, 1955: Die belang van toegepaste geologie en die werk van die geoloog in ons mineral afhanklike besawing

    Directory of Open Access Journals (Sweden)

    P. B. Ackermann

    1955-03-01

    Full Text Available Die toekomstigc ontwikkeling, welvaart en sekuriteit van ons land en die handhawing en verbetering van ons huidige lewenstandaard hang tot’n groot mate af van die doeltreffendste gebruik van ons oorvloedige mineraalhulpbronne, maar beperkte watervoorrade.

  9. Competentiegericht leren in een innovatieve leeromgeving

    NARCIS (Netherlands)

    Wals, A.E.J.

    2007-01-01

    Informatie over twaalf innovatieve leeromgevingen (ILO's) en hun kern, belangrijkste werkvormen en resultaat. De ILO's zijn in eerste instantie bedoeld voor ondernemers maar kunnen deels ook gebruikt worden in het onderwijs

  10. Van SCHEP naar VEP, het voederwaarderingssysteem voor paarden

    NARCIS (Netherlands)

    Bruin, G.; Knaap, J.; Smolders, E.A.A.; Spek, van der M.C.

    1997-01-01

    Veel voedermiddelen zijn geschikt voor paarden en pony's, maar niet ieder voedermiddel bevat evenveel energie, en niet ieder paard heeft een gelijke energiebehoefte. Dit gegeven houdt de vraag actueel hoeveel voer een paard dagelijks nodig heeft.

  11. De functionele eigenschappen van suiker : de rol van suiker

    NARCIS (Netherlands)

    Boekel, van M.A.J.S.

    2010-01-01

    Suiker kan om veel verschillende redenen aan voeding worden toegevoegd. Om de zoete smaak natuurlijk, maar er is meer. Professor Tiny van Boekel van Wageningen Universiteit legt uit waarom suiker zo uniek is.

  12. Onlusten in Kenia: Een beeld van stabiliteit

    NARCIS (Netherlands)

    Dietz, T.; Rutten, M.

    2008-01-01

    Het verkiezingsgeweld in Kenia wordt afgeschilderd als een etnische strijd. Maar de situatie ligt veel ingewikkelder. Het gebrek aan perspectief en de schrijnende kloof tussen arm en rijk lopen niet langs etnische lijnen.

  13. Met een Happy Meal duurzaam leren handelen

    NARCIS (Netherlands)

    Noorduyn, L.; Wals, A.E.J.

    2010-01-01

    Afgestudeerden van groene opleidingen moeten over duurzaamheidscompetenties beschikken, willen ze problemen echt op kunnen lossen. Bijvoorbeeld “omgaan met onzekerheid” en “inleven in een ander”. Maar hoe breng je een student die competenties bij?

  14. Balanced Scorecard voor inkoop

    NARCIS (Netherlands)

    Honing, van der R.; Schotanus, F.

    2003-01-01

    Een Balanced Scorecard kan ontwikkeld worden voor de hele organisatie, maar ook voor onderdelen daarvan. In dit artikel wordt ingegaan op de ontwikkeling van een Balanced Scorecard voor de inkoopafdeling

  15. Het onheil zit vooral onder water (interview J.H.M. Schobben)

    NARCIS (Netherlands)

    Vre, de K.; Schobben, J.H.M.

    2010-01-01

    Als de olie van het wateroppervlak is opgeruimd, lijkt de milieuramp in de Golf van Mexico voorbij. Maar experts waarschuwen voor de gevolgen ónder water. „Polycyclische aromaten zijn kankerverwekkend.”

  16. Broeikasgasmetingen binnen project CTF Flevoland 2009

    NARCIS (Netherlands)

    Wijk, van C.A.P.

    2010-01-01

    Meting van de uitstoot van de broeikasgassen lachgas, methaan en koolzuurgas bij drie (biologische) teeltsystemen: Teeltsysteem met beperkte berijding maar met standaard hoofd grondbewerking; Teelstysteem met onbereden bedden en minimale grondbewerking; Teeltsysteem met standaard grondbewerking en b

  17. De vrijheid van meningsuiting en hate speech: een rechtsvergelijking met de VS

    NARCIS (Netherlands)

    van Vugt, Eva

    2016-01-01

    De vrijheid van meningsuiting is een groot goed in een democratische samenleving maar kan onder bepaalde voorwaarden ingeperkt worden. Haatuitingen genieten bijvoorbeeld in veel westerse democratieën geen (volledige) bescherming. De VS vormt een uitzondering in dit opzicht

  18. Epidemiology and outcomes of renal replacement therapy: results from the ERA-EDTA registry

    NARCIS (Netherlands)

    Kramer, A.

    2011-01-01

    Anneke Kramer onderzocht de epidemiologie van nierfunctievervangende therapie (dialyse of transplantatie) bij zeer ernstig nierfalen. De prevalentie van chronische nierschade is redelijk gelijk binnen Europa. De incidentie van nierfunctievervangende therapie in Europa was lang stijgende maar blijft

  19. Biofilm on orthodontic retention wires : an in vitro and in vivo study

    NARCIS (Netherlands)

    Jongsma, Marije

    2015-01-01

    Orthodontische behandelingen worden steeds populairder. Om na een orthodontische behandeling het resultaat vast te houden, worden retentiedraden achter de voortanden geplaatst. Deze draden zijn heel effectief, maar hebben als nadeel dat er biofilm (tandplaque) aan de draden hecht, waardoor rondom

  20. Leibniz, metafysicus van het atoomtijdperk

    NARCIS (Netherlands)

    Romeijn, J.-W.

    2008-01-01

    Wat heeft de rekenkunde met de metafysica van doen? Massimo Mugnai laat ons in “Leibniz, Filosoof en Mathematicus” kennismaken met Leibniz als grondlegger van de logica. Maar dat is lang niet alles.

  1. Bacterieziekte Erwinia groeiend probleem

    NARCIS (Netherlands)

    Wolf, van der J.M.

    2012-01-01

    Het grootste probleem van Nederlandse pootgoedtelers is tegenwoordig de bacterieziekte Erwinia. Het is een sluipmoordenaar waar nog geen bestrijdingsmiddelen tegen bestaan. Maar onderzoekers komen steeds meer over de bacterie te weten.

  2. Lawaai schaadt

    NARCIS (Netherlands)

    Janssen, S.A.

    2013-01-01

    Wie aan milieuvervuiling denkt, denkt aan giflozingen, het broeikaseffect of vervuilde lucht, maar schade door lawaai, daar hoor je niet vaak over, en dat terwijl lawaai jaarlijks duizenden gezonde levensjaren kost

  3. Genotypische diversiteit en rhizosfeerkolonisatie van DAPG-producerende Pseudomonas spp.

    NARCIS (Netherlands)

    Bergsma-Vlami, M.

    2009-01-01

    Het antibioticum 2,4-diacetylphloroglucinol (DAPG) speelt een belangrijke rol in biologische bestrijding van verschillende plantenpathogenen door fluorescerende Pseudomonas-soorten. DAPG-producerende Pseudomonas-stammen zijn effectief in biologische bestrijding, maar hun saprofytisch vermogen is vaa

  4. Hoornloos fokken vraagt draagvlak ( interview met Jack Windig)

    NARCIS (Netherlands)

    Knaap, J.

    2009-01-01

    Het fokken op hoornloosheid kan een einde maken aan het kunstmatige onthoornen. Dat is goed voor het dierwelzijn vinden veehouders, maar de burger denkt daar in eerste instantie anders over, zo blijkt uit onderzoek van ASG

  5. Nieuw Zorgaanbod: Gesloten jeugdzorg voor adolescenten met ernstige gedragsproblemen

    NARCIS (Netherlands)

    Nijhof, K.S.; Dam, C. van; Veerman, J.W.; Engels, R.C.M.E.; Scholte, R.H.J.

    2010-01-01

    Tot voor kort werd een toenemend aantal jongeren met ernstige gedragsproblemen in jeugdgevangenissen geplaatst. Deze jongeren, ook wel ‘civielrechtelijke’ jongeren genoemd, werden niet geplaatst vanwege veroordelingen voor criminele activiteiten, maar omdat zij beschermd dienden te worden tegen zich

  6. Systeemverantwoordelijkheid in het natuurbeleid

    NARCIS (Netherlands)

    Boonstra, F.G.; Gerritsen, A.L.

    2016-01-01

    Het Rijk is systeemverantwoordelijke voor natuur. Maar over de inhoud van het begrip systeemverantwoordelijkheidbestaat geen eenduidigheid. Er zijn bovendien verschillende manieren waaropsysteemverantwoordelijkheid in de praktijk vorm krijgt. In de ruimtelijke ordening vult het Ministerie vanInfrast

  7. Industriele grondwaterwinningen en de Kaderrichtlijn Water

    NARCIS (Netherlands)

    Wuijts S; Lieste R; LER; mev

    2011-01-01

    De Europese Kaderrichtlijn Water bevat doelstellingen om bronnen van water voor menselijke consumptie veilig te stellen. Deze doelstellingen gelden niet alleen voor de openbare drinkwatervoorziening, maar voor alle toepassingen waarbij het onttrokken water direct voor consumptie wordt gebruikt. Voor

  8. Quantification of the myocardial area at risk using coronary CT angiography and Voronoi algorithm-based myocardial segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Kurata, Akira; Kono, Atsushi; Coenen, Adriaan; Saru-Chelu, Raluca G.; Krestin, Gabriel P. [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Sakamoto, Tsuyoshi [AZE inc, Development Division, Chiyoda, Tokyo (Japan); Kido, Teruhito; Mochizuki, Teruhito [Ehime University Graduate School of Medicine, Department of Radiology, Toon, Ehime (Japan); Higashino, Hiroshi [Yotsuba Circulation Clinic, Department of Radiology, Matsuyama, Ehime (Japan); Abe, Mitsunori [Yotsuba Circulation Clinic, Department of Cardiology, Matsuyama, Ehime (Japan); Feyter, Pim J. de; Nieman, Koen [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus University Medical Center, Department of Cardiology, Rotterdam (Netherlands)

    2015-01-15

    The purpose of this study was to estimate the myocardial area at risk (MAAR) using coronary computed tomography angiography (CTA) and Voronoi algorithm-based myocardial segmentation in comparison with single-photon emission computed tomography (SPECT). Thirty-four patients with coronary artery disease underwent 128-slice coronary CTA, stress/rest thallium-201 SPECT, and coronary angiography (CAG). CTA-based MAAR was defined as the sum of all CAG stenosis (>50 %) related territories (the ratio of the left ventricular volume). Using automated quantification software (17-segment model, 5-point scale), SPECT-based MAAR was defined as the number of segments with a score above zero as compared to the total 17 segments by summed stress score (SSS), difference (SDS) score map, and comprehensive SPECT interpretation with either SSS or SDS best correlating CAG findings (SSS/SDS). Results were compared using Pearson's correlation coefficient. Forty-nine stenoses were observed in 102 major coronary territories. Mean value of CTA-based MAAR was 28.3 ± 14.0 %. SSS-based, SDS-based, and SSS/SDS-based MAAR was 30.1 ± 6.1 %, 20.1 ± 15.8 %, and 26.8 ± 15.7 %, respectively. CTA-based MAAR was significantly related to SPECT-based MAAR (r = 0.531 for SSS; r = 0.494 for SDS; r = 0.814 for SSS/SDS; P < 0.05 in each). CTA-based Voronoi algorithm myocardial segmentation reliably quantifies SPECT-based MAAR. (orig.)

  9. Phreatomagmatic explosive eruptions along fissures on the top of mafic stratovolcanoes with overlapping compound calderas

    Science.gov (United States)

    Nemeth, Karoly; Geshi, Nobuo

    2017-04-01

    On near summit flank eruptions on stratovolcanoes it is commonly inferred that external water to have little or no influence on the course of the eruptions. Hence eruptions are typicaly "dry" that form spatter-dominated fissures and scoria cones. This assumption is based on that in elevated regions - especially on steep slopes - the hydrogeological conditions are not favourable to store large volume of ground water that can have effect on the eruptions. However there is some controversial trend of eruption progression from an early dry eruption below the summit that later turn to be phreatomagmatic as the eruption locus migrates toward the summit. The Suoana Ccrater on top of Miyakejima Island's mafic stratovolcano is a fine example to demonstrate such process. Suona Crater is the topmost crater of the 3 km long fissure aligned chain of small-volume volcanoes that formed in the 7th century flank of the summit region of the Miyakejima mafic stratovolcano. The oval shape crater of Suona (400 x 300 m) is surrounded by a tuff ring that developed over lava flows and epiclastic deposits accumulated in an older caldera forming about a tuff ring that is about 25 m in its thickest section with a basal consistent lava spatter dominated unit gradually transforming into a more scoria-dominated middle unit. A caldera-forming eruption in AD 2000 half-sectioned the Suona Crater exposing of its internal diatreme - crater in-fill - tephra rim succession providing a unique opportunity to understand the 3D architecture of the volcano. Toward the top of the preserved and exposed tuff ring section a clear gradual transition can be seen toward more abundance of chilled dark juvenile particles providing a matrix of a coarse ash that commonly hold cauliflower lapilli and bomb. This transition indicates that the eruption progressed from an early dry explosive phase such as lava fountaining to be a more Strombolian style explosive eruption that later on turned to be heavily influenced by

  10. Phreatomagmatic eruptions through unconsolidated coastal plain sequences, Maungataketake, Auckland Volcanic Field (New Zealand)

    Science.gov (United States)

    Agustín-Flores, Javier; Németh, Károly; Cronin, Shane J.; Lindsay, Jan M.; Kereszturi, Gábor; Brand, Brittany D.; Smith, Ian E. M.

    2014-04-01

    Maungataketake is a monogenetic basaltic volcano formed at ~ 85-89 ka in the southern part of the Auckland Volcanic Field (AVF), New Zealand. It comprises a basal 1100-m diameter tuff ring, with a central scoria/spatter cone and lava flows. The tuff ring was formed under hydrogeological and geographic conditions very similar to the present. The tuff records numerous density stratified, wet base surges that radiated outward up to 1 km, decelerating rapidly and becoming less turbulent with distance. The pyroclastic units dominantly comprise fine-grained expelled grains from various sedimentary deposits beneath the volcano mixed with a minor component of juvenile pyroclasts (~ 35 vol.%). Subtle lateral changes relate to deceleration with distance and vertical transformations are minor, pointing to stable explosion depths and conditions, with gradual transitions between units and no evidence for eruptive pauses. This volcano formed within and on ~ 60 m-thick Plio/Pleistocene, poorly consolidated, highly permeable shelly sands and silts (Kaawa Formation) capped by near-impermeable, water-saturated muds (Tauranga Group). These sediments rest on moderately consolidated Miocene-aged permeable turbiditic sandstones and siltstones (Waitemata Group). Magma-water fuelled thermohydraulic explosions remained in the shallow sedimentary layers, excavating fine-grained sediments without brittle fragmentation required. On the whole, the resulting cool, wet pyroclastic density currents were of low energy. The unconsolidated shallow sediments deformed to accommodate rapidly rising magma, leading to development of complex sill-like bodies and a range of magma-water contact conditions at any time. The weak saturated sediments were also readily liquefied to provide an enduring supply of water and fine sediment to the explosion loci. Changes in magma flux and/or subsequent stabilisation of the conduit area by a lava ring-barrier led to ensuing Strombolian and fire-fountaining eruption

  11. Pyroclastic Density Current Hazards in the Auckland Volcanic Field, New Zealand

    Science.gov (United States)

    Brand, B. D.; Gravley, D.; Clarke, A. B.; Bloomberg, S. H.

    2012-12-01

    The most dangerous phenomena associated with phreatomagmatic eruptions are dilute pyroclastic density currents (PDCs). These are turbulent, ground-hugging sediment gravity currents that travel radially away from the explosive center at up to 100 m/s. The Auckland Volcanic Field (AVF), New Zealand, consists of approximately 50 eruptive centers, at least 39 of which have had explosive phreatomagmatic behaviour. A primary concern for future AVF eruptions is the impact of dilute PDCs in and around the Auckland area. We combine field observations from the Maungataketake tuff ring, which has one of the best exposures of dilute PDC deposits in the AVF, with a quantitative model for flow of and sedimentation from a radially-spreading, steady-state, depth-averaged dilute PDC (modified from Bursik and Woods, 1996 Bull Volcanol 58:175-193). The model allows us to explore the depositional mechanisms, macroscale current dynamics, and potential impact on societal infrastructure of dilute PDCs from a future AVF eruption. The lower portion of the Maungataketake tuff ring pyroclastic deposits contains trunks, limbs and fragments of Podocarp trees (strength of the wood, we calculate that dynamic pressures (Pdyn) of 10-75 kPa are necessary to topple trees of this size and composition. Thus the two main criteria for model success based on the field evidence include (a) Pdyn must be >10 kPa nearer than 0.9 km to the vent, and 35 kPa can be expected within 3 km from source, ensuring complete destruction of the area; Pdyn > 15 kPa up to 5 km from source, resulting in heavy structural damage to most buildings and near destruction of weaker buildings; and Pdyn <10 kPa at ~6 km from source, resulting in severe damage to weaker structures at least up to this distance. This exercise illustrates our ability to combine field measurements with numerical techniques to explore controlling parameters of dilute PDC dynamics. These tools can be used to understand and estimate the damage potential and

  12. Outburst fan deposit from pyroclastic flows, Williamson River canyon, south-central Oregon

    Science.gov (United States)

    Cummings, M. L.; Eibert, D.

    2016-12-01

    Pyroclastic flows from the Holocene eruption of Mount Mazama in the Cascade volcanic arc of Oregon, blocked the narrow (210 to 225 m wide, 35 to 40 m deep), bedrock-lined canyon of the Williamson River. The estimated volume of the long, narrow blockage was 4.4 x 10^7 cubic meters. The blockage eventually failed releasing an impounded lake and depositing a debris fan at the mouth of the canyon. Remnants of the debris fan underlie a gently sloping surface dissected by various abandoned channels of the river. The modern Williamson River cut its channel across the upper part of the fan. Three bedrock units are present as boulders: hydrovolcanic tuff (Di = 2.75 m) derived from tuff cones in the lower reaches of the canyon, distinctly layered geochemically primitive olivine basalt (Di = 3.4 m) that crops out approximately 6 km upstream, and massive basaltic andesite that underlies the channel in the upper canyon and cliffs that define the right bank of the canyon near the mouth. Matrix between boulders and deposits that flank and overlie the boulder deposit are dominated by medium- to fine-grained sand (ASTM; 61-70 wt. % in matrix; 76-100 wt. % elsewhere). Sand grains are predominantly well-rounded phenocryst-bearing glass that vary from massive to moderately vesiculated and crystals of plagioclase and hornblende commonly with attached remnants of groundmass. Crystals are most abundant in the medium- and fine-grained size range (>20 and fragments (twigs and molds) are common in medium-sand and larger. Elongate bars of rounded pumice gravel provide local current directions during the waning stage of the outburst flood. The thickness of the boulder deposit near the mouth of the canyon is not known. Sand deposits are 1 to 1.5 m thick near the mouth of the canyon and thin to 70 cm at about 3.4 km from the mouth of the canyon.

  13. Comparative analyses of glass fragments from brittle fracture experiments and volcanic ash particles

    Science.gov (United States)

    Dürig, Tobias; Mele, Daniela; Dellino, Pierfrancesco; Zimanowski, Bernd

    2012-04-01

    Explosive volcanic eruptions are characterized by the rapid fragmentation of a magmatic melt into ash particles. In order to describe the energy dissipation during fragmentation it is important to understand the mechanism of material failure. A quantitative description of fragmentation is only possible under controlled laboratory conditions. Industrial silicate glasses have a high structural affinity with magmatic melts and have the advantage of being transparent, which allows the study of the evolution of fractures by optical methods on a time scale relevant for explosive volcanism. With this aim, a series of low speed edge-on hammer impact experiments on silicate glass targets has been conducted, leading to the generation of fragments in the grain-size spectra of volcanic ash. In order to verify the general transferability of the experimentally generated fragmentation dynamics to volcanic processes, the resulting products were compared, by means of statistical particle-shape analyses, to particles produced by standardized magma fragmentation experiments and to natural ash particles coming from deposits of basaltic and rhyolitic compositions from the 2004 Grimsvötn and the Quaternary Tepexitl tuff-ring eruptions, respectively. Natural ash particles from both Grimsvötn and Tepexitl show significant similarities with experimental fragments of thermally pre-stressed float glasses, indicating a dominant influence of preexisting stresses on particle shape and suggesting analogous fragmentation processes within the studied materials.

  14. Tecuamburro Volcano, Guatemala geothermal gradient core hole drilling, operations, and preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Goff, S.; Heiken, G.; Goff, F.; Gardner, J. (Los Alamos National Lab., NM (USA)); Duffield, W. (Geological Survey, Flagstaff, AZ (USA)); Martinelli, L.; Aycinena, S. (Swissboring Overseas Corp. Ltd., Guatemala City (Guatemala)); Castaneda, O. (Unidad de Desarrollo Geotermico, Guatemala City (Guatemala). Inst. Nacional de Electrificacion)

    1990-01-01

    A geothermal gradient core hole (TCB-1) was drilled to a depth of 700+ m at the Tecuamburro geothermal site, Guatemala during February and March, 1990. The core hole is located low on the northern flank of the Tecuamburro Volcano complex. Preliminary analysis of cores (>98% core recovery) indicates that the hydrothermal system may be centered in the 4-km-diameter Chupadero Crater, which has been proposed as the source of pyroxene pumice deposits in the Tecuamburro area. TCB-1 is located 300 m south of a 300-m-diameter phreatic crater, Laguna Ixpaco; the core hole penetrates the thin edge of a tuff ring surrounding Ixpaco and zones of hydrothermal brecciation within the upper 150 m may be related to the phreatic blast, dated at 2,910 {sup 14}C years. At the time of this writing, the unequilibrated temperature at a depth of 570m was 180{degree}C. Data on fracturing, permeability, hydrothermal alteration, and temperature will be presented. 3 refs., 3 figs.

  15. A model for the formation of vesiculated tuff by the coalescence of accretionary lapilli

    Science.gov (United States)

    Rosi, Mauro

    1992-07-01

    Observations on phreatomagmatic ash deposits of Phlegraean Fields and Vesuvius supply evidence for the origin of vesiculated tuff in a cool environment. Early deposition by fallout of a matrix-free bed of damp accretionary lapilli is followed by deposition of cohesive mud or a mud rain. The lapilli bed becomes partly or completely transformed into a vesiculated tuff by mud percolation and eventual coalescence of accretionary lapilli with consequent trapping of air originally contained in the interstices. The proposed mechanism accounts for vesiculated tuff formation in distal deposits beyond limits commonly attained by pyroclastic surges. This same mechanism may, nevertheless, also operate in proximal tuff-ring and cone deposits during fallout of phreatomagmatic ash separating bed sets in surge-dominated successions. The sequence of events in the proposed model fits well with the evolution of a cooling phreatomagmatic ash cloud in which early ash aggregation (accretionary lapilli fallout) is followed closely by steam condensation (mud or muddy rainfall). This new model invoking a cool-temperature origin is intended to be complementary to previously proposed theories. Although difficult to assess because of the often complete obliteration of original lapilli, the process is believed to be relatively common in the generasion of vesiculated tuffs within phreatomagmatic deposits.

  16. Analysis of the Gran Desierto, Pinacte Region, Sonora, Mexico, via shuttle imaging radar

    Science.gov (United States)

    Greeley, R.; Christensen, P. R.; Mchone, J. F.; Asmerom, Y.; Zimbelman, J. R.

    1984-01-01

    The radar discriminability of geolian features and their geological setting as imaged by the SIR-A experiment is examined. The Gran Desierto and Pincate volcanio field of Sonora, Mexico was used to analyze the radar characteristics of the interplay of aeolian features and volcano terrain. The area in the Gran Desierto covers 4000 sq. km. and contains sand dunes of several forms. The Pincate volcanio field covers more than 2.000 sq. km. and consists primarily of basaltic lavas. Margins of the field, especially on the western and northern sides, include several maar and maar-like craters; thus obtaining information on their radar characteristics for comparison with impact craters.

  17. Die oorsake vir die ontstaan en besondere aard van die Zion Christian Church

    Directory of Open Access Journals (Sweden)

    M. A. Kruger

    1972-06-01

    Full Text Available Aanvanklik het die Z.C.C. geen opsienbarende groei getoon nie, maar veral sedert die veertigerjare het hulle getalle skerp toegeneem en versprei oor die hele land. In 1963 is Edward Lekganyane toegelaat tot die Stofberg Teologiese Skool van die N.G. Kerk. Sedert die stigting van die Z.C.C. het die groep al verder van die Woord af weg beweeg, maar met hierdie toetrede tot die skool het daar by Edward self ’n mate van verandering gekom.

  18. Economics and Philosophy: more than having fun and making fun

    NARCIS (Netherlands)

    J.J. Vromen (Jack)

    2008-01-01

    textabstractEconomie is leuk, beweren steeds meer populariserende boeken. Deze wetenschap geeft een tegendraadse kijk op de meest uiteenlopende maatschappelijke verschijnselen. Het is de hoogste tijd dat filosofen economie niet langer meer als een armzalige wetenschap afschilderen, maar haar juist d

  19. De keerzijde van de medaille: Sociaal-psychologische en economisch-organisatorische inzichten over teamwerk

    NARCIS (Netherlands)

    Vermeulen, P.A.M.; Benders, J.G.J.M.

    1998-01-01

    Teamwerk is in veel bedrijfskundige publicaties het onderwerp van studie. Deze publicaties zijn over het algemeen positief over het werken in teams. Een klein aantal artikelen geeft aan dat het werken in teams toch zeker niet te makkelijk moet worden opgevat, maar dit leidt meestal niet tot scherpe

  20. Meting van ruimtelijke verdeling van temperatuur en RV met behulp van draadloze minisensoren (Smart Dust). Deel 1 : Programma van wensen en eisen voor het on-line meten van de ruimtelijke verdeling van temperatuur en RV met draadloze minisensoren

    NARCIS (Netherlands)

    Os, van E.A.; Bruins, M.A.; Tuijl, van B.A.J.

    2006-01-01

    De ruimtelijke verdeling van de kasluchttemperatuur en de relatieve vochtigheid is niet gelijk. Door de verschillen ontstaan koude en warme plekken in de kas, maar kunnen ook ziekten en onregelmatige groei van het gewas optreden. In deze studie wordt verslag gedaan van een inventarisatie onder

  1. Het heilige huis : De gotieke vertelling in de Nederlandse literatuur

    NARCIS (Netherlands)

    Buikema, Rosemarie; Wesseling, Lies

    2006-01-01

    Terwijl de gothic novel floreerde in de Engelse, Amerikaanse, Duitse en Franse literatuur, lijkt de Nederlandse literatuur zich tot diep in de twintigste eeuw te hebben onthouden van dit omstreden genre. Weliswaar verschenen er de nodige vertalingen, maar producten van eigen bodem lijken nagenoeg no

  2. Blaise Pascal, une biographie spirituelle

    NARCIS (Netherlands)

    Moulin, Henri Schmitz du

    1982-01-01

    Dat Blaise Pascal (1623-1662) niet alleen een scherpzinnig religieus denker was, maar ook een groot wis- en natuurkundige, mag als bekend worden verondersteld. Als twaal{arige werd hij door zijn vader al meegenomen naar de zittingen van de academie van P. Mersenne, waaraan de voornaamste wis- en nat

  3. Na charisma komt soberheid: charisma en leiderschap

    NARCIS (Netherlands)

    L. Karsten; S. Keulen; R. Kroeze

    2008-01-01

    Waarom worden charismatische leiders, zowel in politiek als bedrijfsleven, historisch gezien altijd opgevolgd door introvertere types? "Een charismatische leider put een organisatie uit", stellen de auteurs van dit artikel. "Maar er is geen enkele reden om aan te nemen dat charismatische leiders def

  4. Bad-Ass Librarians en Guerilla Archivists : Amerikaans activisme onder Trump

    NARCIS (Netherlands)

    Bakker, Marjo

    2017-01-01

    In de eerste honderd dagen van Donald Trumps presidentschap vonden niet alleen in Amerikaanse steden maar ook wereldwijd massale protesten plaats tegen zijn uitlatingen en voorgenomen beleid. Denk bijvoorbeeld aan de Women’s March op 21 januari, de March for Science op 22 april, de People’s Climate

  5. Hong Kong, een studie van de Huisvestingscydus

    NARCIS (Netherlands)

    1996-01-01

    Deze publikatie van de vakgroep Bouwmanagement en Vastgoed beheer is ontstaan uit de behoefte om de resultaten van een excursie nu eens een keer niet onopgemerkt in de archieven van de Stylos excursie verslagen te laten wegkwijnen, maar daarentegen juist een zo groot mogelijk aantal mensen te laten

  6. Boompje klimmen in eigen straat

    NARCIS (Netherlands)

    Bosch, van den F.J.P.

    2010-01-01

    Spelen tussen huizen of op een speelplaats met een zandbak, tegels en een wipkip is leuk, maar het is voor kinderen ook goed om door de bosjes te struinen, in poeltjes te peuren en in bomen te klimmen. Onderzoek naar hoe je in de stad meer van die speelplekken krijgt wijst onder meer uit dat een nat

  7. Opportunities for development of the Moringa sector in Bangladesh : Desk-based review of the Moringa value chains in developing countries and end-markets in Europe

    NARCIS (Netherlands)

    Saavedra Gonzalez, Y.R.; Maden, van der E.C.L.J.

    2015-01-01

    Moringa bomen in Bangladesh en andere ontwikkelingslanden hebben een groot potentieel op het gebied van voedselzekerheid en het genereren van inkomsten, maar lijken vaak te worden onderbenut. De Europese markt biedt wel mogelijkheden voor die leveranciers die bereid en in staat zijn om aan de EU-reg

  8. Exploring the metabolism of Streptomyces coelicolor using mass spectrometry-based metabolomics

    NARCIS (Netherlands)

    Merlo, Maria Eleno

    2012-01-01

    Micro-organismen spelen een belangrijke rol in onze levens: ze worden gebruikt in de industriële productie van brood, kaas, wijn, en bier, maar ook van vele waardevolle chemische stoffen zoals medicijnen en biobrandstoffen. Bovendien leven er enorme aantallen bacteriën en schimmels in het menselijke

  9. Voorwaarden voor BIM

    NARCIS (Netherlands)

    Sebastian, R.

    2012-01-01

    Werken met BIM kent vele voordelen. Maar het ontbreek aan goede afspraken over zaken als aansprakelijkheid, beheer en intellectuele eigendom. Daarom wli de BNA specifieke algemene BIM voorwaarden opstellen. NLingenieurs, Uneto-VNI, bouwend Nederland en TNO doen en denken mee

  10. The Times : russkije milliarderõ ne umejut dvigat brovjami

    Index Scriptorium Estoniae

    2006-01-01

    Sotheby's oksjonil müüdi Pablo Picasso maal "Dora Maar kassiga" 95,2 miljoni dollari eest. Kõige kallimalt müüdud maal oksjonite ajaloos on Picasso "Poiss piibuga", mis müüdi 104 miljoni 168 tuhande dollari eest

  11. Terminal Pleistocene to early Holocene volcanic eruptions at Zuni Salt Lake, west-central New Mexico, USA

    Science.gov (United States)

    Onken, Jill; Forman, Steven

    2017-01-01

    Zuni Salt Lake (ZSL) is a large maar in the Red Hill-Quemado volcanic field located in west-central New Mexico in the southwestern USA. Stratigraphic analysis of sections in and around the maar, coupled with optically stimulated luminescence (OSL) and accelerator mass spectrometry (AMS) 14C dating, indicate that ZSL volcanic activity occurred between ˜13.4 and 9.9 ka and was most likely confined to a ≤500-year interval sometime between ˜12.3 and 11.0 ka. The basal volcanic unit consists of locally widespread basaltic ash fallout interpreted to represent a violent or wind-aided strombolian eruption tentatively attributed to Cerro Pomo, a scoria cone ˜10 km south of ZSL. Subsequent eruptions emanated from vents near or within the present-day ZSL maar crater. Strombolian eruptions of multiple spatter and scoria cones produced basaltic lava and scoria lapilli fallout. Next, a phreatomagmatic eruption created the maar crater and surrounding tephra rim and apron. ZSL eruptions ended with strombolian eruptions that formed three scoria cones on the crater floor. The revised age range of ZSL is younger and more precise than the 190-24 ka 2-sigma age range derived from previous argon dating. This implies that other morphologically youthful, argon-dated volcanoes on the southern margin of the Colorado Plateau might be substantially younger than previously reported.

  12. ‘Ils ont bombardé Reims et nous avons vu cela!’ Eerste Wereldoorlog als katalysator van de verslaggeving ter plaatse

    NARCIS (Netherlands)

    Harbers, Frank

    2016-01-01

    abstractDe Eerste Wereldoorlog beteugelde niet alleen de vrije informatiegaring van de Britse, Nederlandse en Franse pers,maar gaf ook een impuls gaf aan de ontwikkeling van de professionele praktijk van de journalistiek. In het oorlogsgebied en in de buurt van het strijdtoneel raakten de journalist

  13. Smart vehicles, smart traffic: naar een nieuwe mobiliteit

    NARCIS (Netherlands)

    Nijmeijer, H.; Martens, M.H.; Arem, B. van

    2015-01-01

    In ons kleine en drukke Nederland is vlot en veilig verkeer belangrijk. Daarin is nog veel te verbeteren. Nederlanders staan samen zo’n 43 miljoen uur per jaar in de file, het equivalent van 26 duizend full-time banen. Het aantal verkeersdoden neemt af, maar het aantal ernstig gewonden neemt juist t

  14. Effectiviteit van de HRM-implementatie: een procesmodel in vier stappen

    NARCIS (Netherlands)

    Bos-Nehles, Anna Christina; Guest, David

    2015-01-01

    Stel je voor, een organisatie heeft een HR-beleid ontwikkeld dat aan alle eisen van de kunst voldoet: het is gebaseerd op best practices in de sector, het past bij de langeter- mijndoelen van het bedrijf en het is intern congruent. Maar dat wil nog niet zeggen dat het beleid ook overeenkomt met de

  15. Heel Nederland moet bloeden voor deelbelang TNT-postbezorgers

    NARCIS (Netherlands)

    Baarsma, B.

    2011-01-01

    Het kabinet wil dat voor aanstaande vrijdag vaste arbeidscontracten in de postbezorging zijn geregeld. Daarmee helpt het kabinet de concurrenten van TNT om zeep, stelt Barbara Baarsma. Het beleid is enorm kortzichtig, want zonder concurrentie wordt de TNT weer monopolist, maar dan een private. Daar

  16. Warmtepompen in bestaande flatbebouwing

    NARCIS (Netherlands)

    Türkmen, O.S.; Infante Ferreira, C.A.

    2014-01-01

    Nieuwbouw in Nederland is heel duurzaam, maar dit contingent omvat slechts vijf procent van het totale aantal gebouwen. Volgens de EU moet dus ook de bestaande bouw duurzamer. De EU-doelstelling is om het huidige energiegebruik (verwarming en elektriciteit) van gebouwen te verminderen in 2020 met tw

  17. Agressief en hardnekkig

    NARCIS (Netherlands)

    Baars, J.J.P.; Rutjens, A.J.

    2007-01-01

    De champignonteelt ondervindt sinds 2006 hardnekkige problemen met Trichoderma soorten. Tot dan werden infecties met Trichoderma gezien als bijzonder vervelend voor wie het betrof, maar niet als een structureel probleem. Er is dus een trendbreuk opgetreden. Wat is er in hemelsnaam veranderd?

  18. Retourstromen van nutriënten en organische stof naar de biologische landbouw = Reststromen van organische stof en nutriënten naar de biologische landbouw

    NARCIS (Netherlands)

    Dekker, P.H.M.; Bus, C.B.; Geel, van W.C.A.

    2009-01-01

    Doordat de biologische landbouw nutriënten en organische stof afvoert naar de samenleving, maar weinig nutriënten en organische stof uit deze samenleving terugneemt, ontstaat een verliespost in de nutriënten- en organische stofkringloop. De biologische landbouw is voor de nutriëntenvoorziening

  19. Innovaties in 3D-beeldtechniek : Driedimensionaal meekijken met de chirurg

    NARCIS (Netherlands)

    Wieringa, F.P.; Bouma, H.; Beerlage, H.P.

    2012-01-01

    Met de intrede van minimaal invasieve chirurgie werd 3D-zicht minder vanzelfsprekend. Daar komt steeds meer verandering in. In de console van de Da Vinci-robot beschikt de chirurg inmiddels over 3D-zicht, maar de operatieassistenten moeten het nog met tweedimensionaal beeld doen. TNO werkt samen met

  20. Nu ook nog een Brexit uit de Conventie?

    NARCIS (Netherlands)

    Zoethout, C.

    2016-01-01

    De uittreding van het Verenigd Koninkrijk uit de EU is inmiddels realiteit en de nieuwe premier heeft haar positie bepaald: een Brexit is een Brexit. De vraag is alleen nog hoe deze gestalte moet krijgen. Maar door het grote belang van de Britse toekomst binnen of buiten de EU is een ander majeur

  1. Acquisition and Loss of Nationality|Volume 1: Comparative Analyses : Policies and Trends in 15 European Countries

    NARCIS (Netherlands)

    2006-01-01

    Nationaliteit en burgerschap zijn recent in verschillende Europese landen een omstreden beleidsveld geworden. Zorgen over de integratie van immigranten, maar ook pogingen om de banden met emigranten te verstevigen hebben geleid tot wetswijzigingen ten aanzien van het verkrijgen of verliezen van nati

  2. Tussen Reich en Empire : De economische betrekkingen van Nederland met zijn belangrijkste handelspartners, Duitsland, Groot Brittannië en België en de Nederlandse handelspolitiek, 1929 1936

    NARCIS (Netherlands)

    H.A.M. Klemann (Hein)

    1990-01-01

    textabstractIn dit proefschrift wordt uiteengezet hoe Nederland zich in de jaren ’30 economisch staande hield. Daartoe wordt eerst Nederlands monetaire ontwikkeling – de gouden standaardpolitiek – maar ook die van Duitsland, Groot-Brittannië en België bezien, evenals de consequenties daarvan voor de

  3. Schimmels als nieuw wapen tegen malariamuggen

    NARCIS (Netherlands)

    Knols, B.G.J.; Takken, W.

    2008-01-01

    Er gaat ieder jaar veel geld om in de - chemische - bestrijding van malariamuggen. Maar dankzij een veelbelovende schimmel staat een heel nieuwe, duurzame aanpak voor de deur, zeggen medisch entomologen Bart Knols en Willem Takken. 'Het is toch schrijnend dat we aan het begin van de eenentwintigste

  4. Interview; kunst of kliederen; “De ene graffiti is de andere niet”

    NARCIS (Netherlands)

    Keus, R; Vanderveen, G.N.G.

    2010-01-01

    De aanpak van graffiti staat bij veel gemeenten hoog op de agenda. Het tegengaan van overlast en verloedering is hierbij meestal de belangrijkste reden. Maar om een aanpak echt te laten slagen, moet er volgens onderzoekster Gabry Vanderveen eerst goed worden nagegaan welke vormen van graffiti voor

  5. Witte lupine voor kalkrijke bodems : onderzoek over twee jaar naar perspectiefvolle lijnen

    NARCIS (Netherlands)

    Nuijten, H.A.C.P.; Prins, U.

    2014-01-01

    Lupine (Lupinus spp) kan interessant zijn voor zowel biologische als gangbare akkerbouwers die zoeken naar een vlinderbloemig gewas om hun vruchtwisseling te verruimen, niet alleen als veevoer maar ook voor humane voeding. De beschikbare rassen kunnen echter alleen op kalkarme (zand‐)grond geteeld

  6. Lupineveredeling voor kalkrijke bodems : onderzoek naar perspectiefvolle lijnen

    NARCIS (Netherlands)

    Nuijten, E.; Prins, U.

    2013-01-01

    Lupine (Lupinus spp) trekt belangstelling van zowel biologische als gangbare akkerbouwers die zoeken naar een vlinderbloemig gewas om hun vruchtwisseling te verruimen, niet alleen als veevoer, maar ook voor humane voeding. De beschikbare rassen kunnen echter alleen op kalkarme (zand-)grond geteeld

  7. Inflammation @ the heart of Kawasaki disease: Immunogenetic studies on etiology, pathophysiology and treatment effect

    NARCIS (Netherlands)

    Breunis, W.B.

    2010-01-01

    Bij de ziekte van Kawasaki raken de bloedvaten in het lichaam ontstoken. Om onbekende redenen is er een voorkeur voor de kransslagaderen. In Nederland is dit een zeldzame aandoening, maar in andere landen (bijvoorbeeld Japan) komt de ziekte veel vaker voor. Willemijn Breunis onderzocht welke genen

  8. Wees gegroet: Maria in beeld

    NARCIS (Netherlands)

    Vander Stichele, C.

    2009-01-01

    Jean-Luc Godard en Mark Donford-May maakten allebei een film waarin Maria, de moeder van Jezus, een rol speelt. Iedere regisseur portretteert haar op zijn eigen wijze. Allebei overstijgen ze het klassieke beeld van Maria als moeder-maagd, maar zij doen dat op een totaal verschillende manier.

  9. Grooming: over meerderjarigen die internet en jeugdigen misbruiken

    NARCIS (Netherlands)

    Lodder, A.R.

    2015-01-01

    Betoogd wordt dat de intentie van de dader bij grooming een nadrukkelijker rol zou moeten spelen dan thans het geval is. Het internet is voor jong en oud een plek waar veel tijd wordt doorgebracht. Zoals bekend beperken internetgebruikers zich niet tot goedaardige mensen, maar wordt cyberspace ook b

  10. Streptococcus pneumoniae and the host cell

    NARCIS (Netherlands)

    Gradstedt, Per Henrik

    2012-01-01

    Streptococcus pneumoniae is een bacterie die in de menselijke keel-neusholte voorkomt. Vaak is zij ongevaarlijk, maar soms kan zij van leefomgeving veranderen en zich als invasieve ziekteverwekker door het lichaam verspreiden. Dan kan de bacterie longontsteking, bloedvergiftiging of hersenvliesontst

  11. Amensie en demensie met verwysing na die intellek

    Directory of Open Access Journals (Sweden)

    P. C. W. Deppe

    1958-03-01

    Full Text Available ,,Es ist der Geist der sich den Kórper baut” het Goethe gesê en hy het daardeur die monistiese begrip in die psigiatrie beklemtoon. Dwarsdeur die eeue het die ontwikkelingsgeskiedenis van die mens maar telkens getoon hoedat daar by die mens veral, nie anders gedink kan word dan as 'n psigosomatiese eenheid nie. 

  12. Interplay between lipoproteins, the complement system and blood cells in atherosclerosis

    NARCIS (Netherlands)

    Klop, Boudewijn

    2014-01-01

    Er is toenemend bewijs dat het niet noodzakelijk is om cholesterol en vetzuren in nuchtere toestand te meten, maar dat een niet-nuchtere meting in de meeste gevallen ook kan volstaan. De ontwikkeling van aderverkalking is complex en gaat veel verder dan alleen het cholesterolgehalte in het bloed. Ad

  13. Vijf schimmels zijn boosdoener : zwarte vlekken op peen kosten teler veel geld Interview met Huub Schepers

    NARCIS (Netherlands)

    Hurkens, Y.; Schepers, H.T.A.M.

    2010-01-01

    Telers van peen hebben regelmatig te maken met zwarte vlekken op de penen. De peen gaat blank, onbeschadigd de bewaring in, maar bij het uitschuren zijn er kleine zwarte vlekjes te zien. Deze kunnen door vijf schimmels veroorzaakt worden. Om de kans op zwarte plekken zo klein mogelijk te houden geve

  14. Miniketen helpt introductie nieuwe fruitrassen vooruit

    NARCIS (Netherlands)

    Dubbeldam, R.

    2006-01-01

    Santana is een nieuwe appel. Milieuvriendelijk te telen en ook nog eens lekker van smaak. Maar hoe breng je zo’n nieuwe appel op de markt en bij de consument? Een miniketenaanpak kan een zinvol vehikel zijn. In een miniketen kun je het hele traject van teler tot de consument volgen, begeleiden, en

  15. De introduktie van streekproducten bij grote afnemers

    NARCIS (Netherlands)

    Kortstee, H.J.M.

    2008-01-01

    Hoe kunnen grote landelijk opererende bedrijven beter inspringen op de toenemende, maar vaak nog latente vraag naar belevingsproducten van het platteland? Om deze vraag van een antwoord te voorzien is gekeken hoe de introductie van streekproducten bij vier landelijk opererende afnemers in de praktij

  16. Miraculeus bewaard: middeleeuwse Utrechtse relieken op reis: de schat van de oud-katholieke Gertrudiskathedraal

    NARCIS (Netherlands)

    de Kruijf, A.C.

    2011-01-01

    Op veilingsites worden regelmatig eigendommen van popsterren en sporthelden aangeboden. De wc-bril van John Lennon, maar ook de rijstkom van Mahatma Gandhi wisselden onlangs voor grof geld van eigenaar. In de middeleeuwen was het niet anders, al waren toen vooral religieuze idolen populair.

  17. "Please Don't Stop the Music..." : the influence of music and radio on cognitive processes, arousal and driving performance

    NARCIS (Netherlands)

    Unal, Ayca Berfu

    2013-01-01

    Muziek luisteren tijdens autorijden beïnvloedt rijprestatie nauwelijks Rijden met de radio aan of een lekker muziekje in de cd-speler vinden de meeste automobilisten prettig. Ze zetten de radio vrijwel zonder nadenken aan. Maar is dat wel veilig? De invloed van muziek op de rijprestatie is niet

  18. Biofilm on orthodontic retention wires : an in vitro and in vivo study

    NARCIS (Netherlands)

    Jongsma, Marije

    2015-01-01

    Orthodontische behandelingen worden steeds populairder. Om na een orthodontische behandeling het resultaat vast te houden, worden retentiedraden achter de voortanden geplaatst. Deze draden zijn heel effectief, maar hebben als nadeel dat er biofilm (tandplaque) aan de draden hecht, waardoor rondom de

  19. De boze buitenwereld buiten houden

    NARCIS (Netherlands)

    Koch, G.; Elbers, A.R.W.

    2005-01-01

    Zolang vaccinatie niet is toegestaan, is het opwerpen van een barriere de enige verdediging tegen insleep van AI. De dreiging is groot, maar Azië leert ons dat bioveiligheid wel degelijk kan werken. Het is een zaak van strenge en consequent uitgevoerde maatregelen

  20. Nederlandse consumptie en energiegebruik in 2030, een verkennende basis van twee lange termijn scenario's

    NARCIS (Netherlands)

    Vringer K; Aalbers TG; Drissen E; Hoevenagel R; Bertens CAW; Rood GA; Ros JPM; Annema JA; LAE

    2001-01-01

    In de agenda van het vierde Nationale Milieu Beleidsplan (NMP4) (VROM, 1999) staat duurzaamheid en kwaliteit van leven centraal. Kwaliteit van leven wordt beinvloed door consumptie, maar ook door de daaruit volgende milieudruk. De milieudruk die wordt veroorzaakt door de consumptie van personen

  1. Produktieniveau en bedrijfsresultaat bij appelen

    NARCIS (Netherlands)

    Joosse, M.L.

    1986-01-01

    Het economisch resultaat van een appelaanplant wordt beinvloed door de omvang van de produktie, maar ook door de prijs per kilogram. De prijs per kilogram is in het algemeen hoger, naarmate de vruchtgrootte toeneemt. Anderzijds blijkt een hoger produktieniveau samen te gaan met lagere gemiddelde vru

  2. GIS-analyse van risico vuil oppervlaktewater voor vee in Friesland

    NARCIS (Netherlands)

    Querner, E.P.; Harmsen, J.; Dolfing, J.

    2004-01-01

    Vee dat in de wei loopt, drinkt water uit de sloot. Bij gezondheidsproblemen met vee wordt daarom ook gekeken in de richting van de kwaliteit van het slootwater, omdat dit water niet altijd even schoon is. De waterkwaliteit in sloten wordt beïnvloed door menselijke activiteiten, maar ook door natuur

  3. Knelpuntenanalyse oppervlaktewaterkwaliteit voor veedrenking; een toepassing m.b.v. een GIS-analyse in Friesland

    NARCIS (Netherlands)

    Querner, E.P.; Frissel, J.Y.; Harmsen, J.; Dolfing, J.; Toorn, van den A.

    2004-01-01

    Vee dat in de wei loopt, drinkt water uit de sloot. Een aantal veehouders heeft daardoor te maken met gezondheidsproblemen bij het vee. De waterkwaliteit in sloten wordt beïnvloed door een groot aantal factoren enerzijds het gevolg van menselijke activiteiten, maar ook van natuurlijke processen. Om

  4. Maken accountants systematisch onbewuste beoordelingsfouten?

    NARCIS (Netherlands)

    Meijs, K. (Koert); Grinsven, J.H.M. (Jürgen)

    2014-01-01

    Harvard Business Review auteurs Bazerman, Loewenstein en Moore stellen in hun artikel “Why good accountants do bad audits” (2002) dat het werkelijke probleem bij accountantscontroles niet zit in bewuste fraude door accountants maar schuilt in onbewuste beoordelingsfouten. Zij beroepen zich enerzijds

  5. Evaluatie van het pilotproject: SCEN verpleegkundigen & verzorgenden.

    NARCIS (Netherlands)

    Albers, G.; Onwuteaka-Philipsen, B.D.; Francke, A.L.

    2012-01-01

    Uit de evaluatie van de helpdesk SCEN v & v voor steun en consultatie bij euthanasie, blijkt dat de speciaal daarvoor geschoolde medewerkers goed werk hebben geleverd, maar dat ze te weinig zijn gebeld om door te gaan met het project. Kennelijk krijgen verpleegkundigen en verzorgenden hun informatie

  6. Ex ante Implementatietoetsing van Beleid, Een Methodiek Gebaseerd op Synergie Tussen Risicomanagement en Verandermanagement (Ex Ante Test for Policy Implementation - A Method Based Upon Synergy Between Risk Management an Change Management)

    Science.gov (United States)

    2006-12-01

    informele wijze van veranderen wordt gekeken zien we de gele benadering sterker naar voren komen. De krachten van politieke en militaire macht, de vele...8217 risico’s kunnen genegeerd worden maar de ’rode’ risico’s moeten zeker meegenomen worden. De ’ gele ’ risico’s kunnen per geval geevalueerd worden. Evenals

  7. Lexicon

    NARCIS (Netherlands)

    Coumans, Anke; Altena, Allie van; Faber, Johan; Niks, Simon; Straatman, Bibi

    2013-01-01

    In deze publicatie is een aantal vrij willekeurige concepten gebundeld die de verbeelding een plaats geven en die niet alleen verbonden wordt met de wereld buiten de taal, maar die ons ook laten zien hoe de taal ons kan helpen om die wereld te doorgronden. Dit alles vanuit het geloof dat taal net al

  8. Groei van de beverpopulatie: lusten en lasten

    NARCIS (Netherlands)

    Vreugdenhil, S.; Dekker, J.J.A.; Dijkstra, V.D.

    2012-01-01

    Het aantal bevers is in Nederland sterk gegroeid. In 1988 werden de eerste dieren losgelaten in de Biesbosch, en in 2012 wordt het aantal Nederlandse bevers al geschat op zeker 600 volwassen dieren. Bevers zijn door hun bijzondere gedrag een aanwinst voor onze natuur. Maar ditzelfde gedrag kan ook l

  9. De jacht op het geheim van cacao

    NARCIS (Netherlands)

    Hollman, P.C.H.

    2008-01-01

    Je kans op een dodelijke hartaanval halveert als je elke dag een groot paaseitje pure chocolade eet, blijkt uit een recente Nederlandse epidemiologische studie. En ook andere studies laten zien dat consumptie van cacao beschermt tegen hart- en vaatziekten. Maar het is nog een raadsel hoe dat precies

  10. De Eeuwwende 1700 (dl. 1): Filosofie en Natuurwetenschappen

    NARCIS (Netherlands)

    Klukhuhn, A.; Wielema, M.R.; Dooren, W. van; Zweerman, Th.H.; Snelders, H.A.M.; Pater, C. de; Palm, L.C.

    1991-01-01

    Aan het einde van de zeventiende eeuw wordt de filosofische discussie sterk bepaald door het spinozisme, het empirisme van Locke en het rationalisme van Leibniz. Spinoza was al overleden (1676), maar zijn invloed is sterk; Locke (overleden in 1804) en Leibniz (overleden in 1716) zijn op het hoogtepu

  11. Het boeck der natuere : Nederlandse geleerden en de wonderen van Gods schepping, 1575-1715

    NARCIS (Netherlands)

    Jorink, Henricus Gerardus Maria

    2004-01-01

    Nederlandse wetenschapsbeoefening in de Gouden Eeuw was veel minder pragmatisch en praktijkgericht dan wordt gedacht. De natuur werd niet bestudeerd om de wetenschap op een hoger plan te brengen, maar juist om God beter te kunnen eren. Dit concludeert historicus drs. Eric Jorink. Hij promoveert op 1

  12. Bariona, Sartre en zijn relatie met het christendom

    NARCIS (Netherlands)

    Stralen, J.J.M. van

    2006-01-01

    Het existentialisme (1935-1960) ontwikkelde zich binnen een christelijke traditie en heeft – ondanks de felle uithalen door sommige schrijvers naar de religie – gedurende haar kortstondige bestaan talrijke christelijke concepten een nieuw, maar ook antro-pocentrisch leven ingeblazen. Sartres project

  13. Inflammation @ the heart of Kawasaki disease: Immunogenetic studies on etiology, pathophysiology and treatment effect

    NARCIS (Netherlands)

    Breunis, W.B.

    2010-01-01

    Bij de ziekte van Kawasaki raken de bloedvaten in het lichaam ontstoken. Om onbekende redenen is er een voorkeur voor de kransslagaderen. In Nederland is dit een zeldzame aandoening, maar in andere landen (bijvoorbeeld Japan) komt de ziekte veel vaker voor. Willemijn Breunis onderzocht welke genen m

  14. Ongekende varkenshouderij floteert op Corsica

    NARCIS (Netherlands)

    Commandeur, M.A.M.

    2009-01-01

    De intensivering van de varkenshouderij in Europa in de tweede helft van de vorige eeuw betekende een krachtige trendbreuk met de huishoudelijke varkenshouderij van daarvoor. In heel Europa? Neen. Op Corsica ontstond er weliswaar een ontwikkeling naar gespecialiseerde bedrijven, maar die markante tr

  15. Effecten van onderwatergeluid op walvissen : Op zoek naar aanvaardbare grenzen

    NARCIS (Netherlands)

    Lam, F.P.A.

    2012-01-01

    Walvissen ‘kijken’ onder water met hun oren, maar er zijn steeds meer geluidsbronnen op zee. Hoe komen we er achter wanneer walvissen last krijgen van het onderwatergeluid dat door de mens wordt gemaakt? Een van deze geluidsbronnen is sonar van de marine voor het opsporen van onderzeeboten. TNO onde

  16. Voedselzekerheid is complex vraagstuk

    NARCIS (Netherlands)

    Dorp, van M.

    2010-01-01

    In 2009 had meer dan een miljard mensen te weinig te eten, het hoogste aantal sinds 1970. Dat blijkt uit cijfers van de VN. Jarenlang daalde het aantal mensen met honger, maar de laatste jaren is die trend gekeerd, mede door de wereldwijde economische crisis en de enorme prijsstijgingen van voedsel

  17. Genetiese, morflogiese en gedragsstudies van Cyrtophora spp . (Araneae: Araneidae in Suid Afrika

    Directory of Open Access Journals (Sweden)

    P.Z.N. Franzini

    2012-03-01

    Full Text Available Spinnekoppe van die genusCyrtophoravorm deel van die familieAraneidaeen staan algemeenbekend as tent-web spinnekoppe te danke aan die unieke vorm van hul web. ‘n Totaal van 41Cyrtophora spp.is in die hele wêreld bekend en vyf van hulle is uit Afrika aangeteken, maar geen formeel in Suid-Afrika nie.

  18. Beerling : 'GNO vergt een langduriger toepassing voor een goed effect' : interview

    NARCIS (Netherlands)

    Arkesteijn, M.; Beerling, E.A.M.

    2009-01-01

    Het gebruik van gewasbeschermingsmiddelen van natuurlijke oorsprong (GNO's) wint terrein door het optreden van resistentie tegen chemische middelen en doordat de markt erom vraagt. Er zijn diverse goed werkende GNO's op de markt, maar een teler moet er anders mee omgaan dan met chemische middelen. B

  19. The network is the message : Fase 1: het net ophalen

    NARCIS (Netherlands)

    Veen, Gerrita van der; Willemsen, Lotte M.; Waardenburg, Thijs; Brussee, Rogier

    2016-01-01

    Veel bedrijven staan reeds via social media als Facebook of Twitter in contact met hun gebruikers en iedere serieuze marketingcampagne werkt tegenwoordig met likes en tweets. Hoeveel ze daarin investeren en in de toekomst willen blijven doen, hangt af van de effectiviteit van social media. Maar wann

  20. Aanvullende COCO-berekeningen in het kader van nazorg van het DynAqua-project (kokkelkweek deel)

    NARCIS (Netherlands)

    Vries, de P.; Veenstra, F.A.

    2007-01-01

    COCO (COmputer COckle model) is ontwikkeld door het voormalig Nederlands Instituut voor Visserij Onderzoek (RIVO), tegenwoordig bekend als Wageningen IMARES. COCO berekent ondermeer de groei van een individuele kokkel, maar kan ook informatie met betrekking tot de productie van pseudo-feces oplevere

  1. Shooting the Family : Transnational Media and Intercultural Values

    NARCIS (Netherlands)

    2005-01-01

    Onder invloed van media als sateliettelevisie en cinema, is de rol van de familie in de hedendaagse, multiculturele samenleving aan het veranderen. Als gevolg van globalisatie en migratie staat de familie onder druk: de familie 'shot to pieces'. Maar tegelijkertijd keren zowel nieuwe als traditionel

  2. Praktijkevaluatie van 'piglet snatching'

    NARCIS (Netherlands)

    Smits, J.M.; Binnendijk, G.P.; Eijck, I.A.J.M.

    2002-01-01

    Bij piglet snatching worden biggen van een zeug direct bij de geboorte weggevangen en overgelegd naar een zeug op een ander bedrijf. In de praktijk is dit een goede, welzijnsvriendelijke manier om biggen van een bedrijf met een lage ziektevrij-status maar met een hoge genetische waarde over te breng

  3. Haalbaarheid gebruik onbemande meetvliegtuigjes bij calamiteiten

    NARCIS (Netherlands)

    Tukker K; Jentink HW; van Putten EM; Roelofsz MC; Muller CF; Vreeken J; M& M; M& V

    2014-01-01

    Onbemande vliegtuigjes die zijn toegerust met moderne meetinstrumenten, maken het in principe mogelijk om bij calamiteiten metingen hoog in de lucht te verrichten. Dat kan tot nu toe alleen nog op de grond. Het bleek mogelijk om een radioactieve bron vanuit een onbemand vliegtuigje te meten, maar om

  4. Voorwaarden voor BIM

    NARCIS (Netherlands)

    Sebastian, R.

    2012-01-01

    Werken met BIM kent vele voordelen. Maar het ontbreek aan goede afspraken over zaken als aansprakelijkheid, beheer en intellectuele eigendom. Daarom wli de BNA specifieke algemene BIM voorwaarden opstellen. NLingenieurs, Uneto-VNI, bouwend Nederland en TNO doen en denken mee

  5. Videogames en gender : over spelende meiden, sexy avatars en huiselijkheid op het scherm

    NARCIS (Netherlands)

    Vosmeer, M.S.

    2010-01-01

    Nog niet zo lang geleden waren videogames typische mannenmedia, maar tegenwoordig zijn er steeds meer meisjes en vrouwen die ook games spelen. Vergeleken met mannelijke gamers is deze groep echter tamelijk onzichtbaar, en is er weinig over hen bekend. In dit boek komen vrouwelijke gamers in verschil

  6. Praktijk weerbarstig bij aanpak kalverdiarree

    NARCIS (Netherlands)

    Cappellen, van J.; Boumans, I.J.M.M.; Stassen, E.N.

    2013-01-01

    Veehouders weten goed welke maatregelen er zijn tegen kalverdiarree, maar passen ze in de praktijk vaak niet toe. ‘Geen noodzaak’, ‘te weinig tijd’ of ‘te onpraktisch voor de eigen situatie’ zijn veelgehoorde argumenten om geen actie te ondernemen.

  7. Kroonjuwelen van de Kaap

    NARCIS (Netherlands)

    Sluiter, L.; Schaminee, J.H.J.

    2012-01-01

    'Kroonjuwelen van de Kaap' neemt de fascinerende wereld van de Kaap onder de loep. Niet alleen de biologische rijkdom van het fynbos, maar ook de geschiedenis van het gebied en zijn bewoners. Na eeuwenlang op zichzelf te hebben geleefd, in nauw samenspel met de natuur, kregen de oorspronkelijke bewo

  8. RELIGIOUS FANATICS THAT BECAME POLITICAL HEROES: THE HISTORICAL DISTORTIONS OF THE BULHOEK MASSACRE

    Directory of Open Access Journals (Sweden)

    D.H. Makobe

    2012-02-01

    Full Text Available In die slotartikel word die bronne asook die polemiek rondom die Bulhoekopstand ontleed. Gedurende die sewentigerjare is die opstand beskou as deel van die Suid-Afrikaanse swart versetgeskiedenis. Nou word die pleidooi gelewer dat die Bulhoekopstand nie uit 'n politieke oogpunt benader moet word nie maar dat die feite krities ontleed moet word.

  9. Cow health: bacteriological diagnostic examination

    NARCIS (Netherlands)

    Smith, H.E.; Sampimon, O.C.; Lam, T.J.G.M.

    2007-01-01

    Mastitis wordt vrijwel altijd veroorzaakt door een infectie met bacteriële ziektekiemen. Virale infecties kunnen ook een rol spelen, maar zijn van ondergeschikt belang. Dit artikel zal daarom alleen ingaan op diagnostisch onderzoek van bacteriele ziektekiemen. Er zijn veel verschillende bacteriën di

  10. Business Continuity Management: een zorg voor de omgeving?

    NARCIS (Netherlands)

    Rodenhuis, W.K.F. (Wilbert)

    2011-01-01

    Business continuity management (BCM) is allang niet meer alleen 'disaster recovery planning '. In dit artikel een schets van de ontwikkelingen van BCM in de afgelopen decennia tot wat het nu is: een holistisch managementproces. Maar inmiddels is er ook sprake van verwevenheid van de ondernem

  11. Maatschappij zonder managers

    NARCIS (Netherlands)

    Dicke, M.

    2007-01-01

    Mieren zijn een zeer succesvolle insectengroep. Niet zo zeer in aantal soorten: er zijn ongeveer 9.500 mierensoorten ofwel 0.5% van alle soorten op aarde zijn mieren. Maar veeleer in aantal individuen. Hun aantallen zijn enorm, evenals hun biomassa. Volgens schattingen is het gewicht aan mieren op a

  12. De staafmier Ponera coarctata in Nederland (Hymenoptera: Formicidae)

    NARCIS (Netherlands)

    Noordijk, J.; Boer, P.; Wijnhoven, H.; Raemakers, I.P.

    2008-01-01

    De staafmier staat bekend als zeldzaam, maar dat hangt samen met haar verborgen levenswijze. In deze bijdrage word eerst enkele opmerkelijke vindplaatsen van de staafmier uit het stedelijk gebied beschreven. De beschreven vondsten duiden erop dat de staafmier goed kan voorkomen in niet-natuurlijke s

  13. Nieuws over de Nederlandse mieren (2004-2008) (Hymenoptera: Formicidae)

    NARCIS (Netherlands)

    Boer, P.

    2009-01-01

    In het boek De wespen en mieren van Nederland uit 2004 wordt een overzicht gegeven van de kennis van de Nederlandse mierenfauna. In dit artikel worden de nieuwe inzichten samengevat. Zo zijn maar liefst zes nieuwe soorten voor ons land te melden en van diverse andere soorten is interessante nieuwe i

  14. Herfstakkoord kost vooral glastuinders geld

    NARCIS (Netherlands)

    Veen, van der H.B.

    2012-01-01

    Op 1 oktober hebben Rutte en Samson het deelakkoord over de begroting van 2013 gepresenteerd, bijgenaamd het herfstakkoord. Net als bij het Lenteakkoord kost dit vooral glastuinders geld, maar ook grote akkerbouwers. In diverse gemeenten is bij meer dan 15% van de bedrijven het nadelig effect groter

  15. The Politics of Justification : Party Competition and Welfare-State Retrenchment in Denmark and the Netherlands from 1982 to 1998

    NARCIS (Netherlands)

    Green-Pedersen, Christoffer

    2002-01-01

    The Politics of Justification onderzoekt de bezuinigingen op de sociale zekerheid die plaatsvonden in Nederland en Denemarken in de periode 1982-1998. Het korten op sociale voorzieningen ligt politiek uiterst gevoelig, maar toch snijden regeringen in hun uitgaven. Green-Pedersen bepleit dat regering

  16. Het wordt stil in de bijenkast : de wetenschap over bijensterfte (interview met A. van 't Hoog, T. Blacquiere, C. van Dooremalen)

    NARCIS (Netherlands)

    Hoog, van 't A.; Blacquiere, T.; Dooremalen, van C.; Cornelissen, B.

    2013-01-01

    Er is iets goed mis met de honingbij: ’s winters legt een derde van de volken het loodje. Geleidelijk aan krijgt de wetenschap meer inzicht in mogelijke oorzaken van deze bijensterfte, maar één boosdoener is (nog) niet aan te wijzen.

  17. Een letterlijke frisse bries in het ontwerponderwijs landschapsarchitectuur

    NARCIS (Netherlands)

    Lenzholzer, S.

    2010-01-01

    Hoe beïnvloedt het atmosferisch klimaat in Nederland de structuur van stad en landschap? Met die vraag heeft het ontwerponderwijs zich eigenlijk nooit integraal bezig gehouden. Maar daar is nu verandering in gekomen: in Wageningen hebben studenten landschapsarchitectuur binnen het project 'Future Ci

  18. Een beter leven met groene daken en muren

    NARCIS (Netherlands)

    Tonneijck, A.E.G.

    2006-01-01

    De toepassing van ‘gezond groen’ wordt vooral toegespitst op ‘ongezonde plekken’, zoals direct langs de snelweg. Maar het loont om wat beter na te denken over de inzet van groen. Tenminste, als het de bedoeling is om de concentraties van vuile stoffen op die ongezonde plekken zelf te verlagen. Een b

  19. Biodiversiteit in tuin en plantsoen

    NARCIS (Netherlands)

    Hoffman, M.H.A.

    2010-01-01

    Een rijk en gevarieerd groen in de stad wordt niet alleen door burgers erg gewaardeerd, maar het kan ook een uitstekende bijdrage leveren aan de biodiversiteit. Het biedt veel soorten insecten, vogels en andere dieren nieuwe levenskansen. En bovendien wordt zo de natuur dicht bij huis gehaald. Deze

  20. "Dit kunnen dak- en gevelgroen voor u betekenen"

    NARCIS (Netherlands)

    Hop, M.E.C.M.; Hiemstra, J.A.

    2013-01-01

    Groene ruimten in de stad zijn een leverancier van diensten als het gaat om het leefbaar houden van de stad. Het traditionele groen op maaiveldniveau speelt hierin de hoofdrol. Maar specifieke stadsproblemen als zomerhitte en wateroverlast na stortbuien doen zich vooral voor in volgebouwde binnenste

  1. Fusarium in uien : en rasverschillen in aantasting : evaluatie van een biotoets

    NARCIS (Netherlands)

    Visser, de C.L.M.

    1999-01-01

    Tolerante rassen kunnen een uitkomst bieden voor telers met percelen die aangetast zijn door Fusarium oxysporum f.sp. cepea. De biotoets kan inzicht geven in de kans op schade door Fusarium maar kost veel tijd en is daarmee relatief duur

  2. Studies on smoking in patients with inflammatory bowel disease and liver transplant recipients

    NARCIS (Netherlands)

    Heide, Frans van der

    2011-01-01

    Hoe meer ze roken, hoe minder patiënten met colitis ulcerosa last hebben van hun ziekte. Dat blijkt uit het promotieonderzoek van Frans van der Heide. Ook bevestigt de promovendus eerdere studies waaruit blijkt dat rokers minder kans hebben om colitis ulcerosa te ontwikkelen. Maar op een verwante ch

  3. Cool : wat wij kønnen leren van de Scandinavie͏̈rs

    NARCIS (Netherlands)

    Hospers, Gerrit J.; Vos, Martin; Krijnsen, Marco

    2015-01-01

    We slapen in een bed van IKEA, eten Noorse zalm, zweren bij Deense thrillerseries en komen tot rust in een Finse sauna. Maar wat weten we verder eigenlijk van Scandinavië? Lees in dit boek vol inspirerende verhalen waarom ze in het Noorden zo goed zijn in design en nieuwe technologie, een minister o

  4. Referentietoets poinsettia : ontwikkeling en beschrijving van het protocol

    NARCIS (Netherlands)

    Gelder, de A.; Wurff, van der A.A.M.

    1997-01-01

    De sortimentsontwikkeling bij Poinsettia gaat niet snel, maar wel gestaag door. Telers en veredelaars werken bij de beoordeling van nieuwe cultivars samen in sortimentsopplantingen. De informatie hieruit kunnen zij benutten bij de samenstelling van hun sortiment. Voor de afzet heeft dit echter geen

  5. Crisis redt ruimtelijke ordening

    NARCIS (Netherlands)

    L. Janssen-Jansen

    2011-01-01

    Wie buiten om zich heen kijkt, ziet een enorm overschot aan vastgoed variërend van leegstaande kantoren en winkels en eindeloos te koop staande woningen tot stilliggende bouwprojecten. In de vakwereld en media krijgt de fi nanciële crisis de schuld. Maar is de crisis wel de schuldige? Of juist de re

  6. Risicoreductie: het venijn zit in de staart

    NARCIS (Netherlands)

    Wild, A.F.; Versluis, V.

    2015-01-01

    In het kader van risicoacceptatie betekent risicomijden dat we de aandacht bij de ‘zwarte zwanen’ houden door prioriteit te geven aan risico’s met een kleine kans van optreden en een groot gevolg. Maar een risicomijdende houding levert ook voordelen op bij risicoreductie. Door bij het reduceren van

  7. Schematherapie bij adolescenten

    NARCIS (Netherlands)

    M.T. Geerdink; E.J. Jongman; H.A. Scholing

    2008-01-01

    Schematherapie (ST) werd ontwikkeld bij volwassen patiënten, maar wordt tegenwoordig ook gebruikt bij adolescenten (van circa 16 tot 23 jaar) die persoonlijkheidsproblemen ontwikkelen. Er is tot nu toe vrijwel geen literatuur over ST bij adolescenten. Een zoekactie op de termen ‘schema focused thera

  8. Logica en Recht: Naar een Rijkere Relatie

    NARCIS (Netherlands)

    van Benthem, J.; Groenhuijsen, M.; Hondius, E.; Soeteman, A.

    2014-01-01

    Logica en recht hebben gemeenschappelijke interesses, wellicht zelfs gezamenlijke wortels. Het gelijktijdig ontstaan van de logica in drie grote wereldculturen rond 500 B.C. wordt soms verklaard vanuit reflectie op de toen reeds lang bestaande juridische praktijk. Maar die juridische praktijk wordt

  9. Tussenrapport : uitloop biologische varkens : verslag studiemiddag biologische veehouderij PO-34

    NARCIS (Netherlands)

    Anonymous,

    2004-01-01

    Bij deze tussenrapportage zijn al een aantal (voorlopige)conclusies te trekken enaanbevelingen te doen rondom de uitloop voor varkens. Uit het thema dier komt naar voren dat bij vleesvarkens de meeste spoelwormeieren in de verharde uitloop te vinden zijn en dat er maar een gering aantal volwassen wo

  10. De relatie tussen roken en cafeïnegebruik en het (genetische) mechanisme wat hieraan ten grondslag ligt [The association between smoking and caffeine use and the (genetic) mechanism underlying this association

    NARCIS (Netherlands)

    Treur, J.L.

    2016-01-01

    Het is aangetoond dat roken sterk samenhangt met koffiegebruik, maar of dit ook zo is voor roken en andere cafeïnehoudende dranken is nog onbekend. Ook weten we nog niet welk mechanisme hieraan ten grondslag ligt. Met vragenlijstgegevens heeft de auteur allereerst de relatie tussen roken en

  11. De tomatenkaart is klaar, wat nu?

    NARCIS (Netherlands)

    Finkers, H.J.; Visser, R.G.F.

    2013-01-01

    In 2012 publiceerde Nature de genomische sequentie van de tomaat. Maar daarmee is het werk niet af, zegt Richard Finkers. Hij bepaalde de basenvolgorde van nog eens 150 verwanten van de modeltomaat, om plantenveredelaars in staat te stellen op zoek te gaan naar nieuwe genen in oude rassen.

  12. Leiderschap met social media: do's and don'ts

    NARCIS (Netherlands)

    Effing, Robin

    2010-01-01

    Het leiderschap van de Amerikaanse president Barack Obama is op verschillende manieren vernieuwend. Zijn succes heeft hij mede te danken aan zijn effectieve inzet van social media. Door het speelse karakter van deze nieuwe media wordt de bedrijfsmatige inzet ervan echter meestal onderschat. Maar als

  13. Te hard van stapel gelopen.

    NARCIS (Netherlands)

    W-J. Verhoeven (Willem-Jan)

    2008-01-01

    textabstractHoe goed we ook trachten de samenleving te organiseren, fraude maakt er deel van uit. Dit blijkt uit spraakmakende grote schandalen zoals de Enron-zaak, de Bouwfraude-zaak en de Nigerian letter scams. Maar fraude komt ook op minder geruchtmakende schaal voor, zoals oplichting op veilings

  14. Leiderschap met social media: do's and don'ts

    NARCIS (Netherlands)

    Effing, Robin

    2010-01-01

    Het leiderschap van de Amerikaanse president Barack Obama is op verschillende manieren vernieuwend. Zijn succes heeft hij mede te danken aan zijn effectieve inzet van social media. Door het speelse karakter van deze nieuwe media wordt de bedrijfsmatige inzet ervan echter meestal onderschat. Maar als

  15. Ontwikkeling van een toets ter detectie groene schimmel in compost

    NARCIS (Netherlands)

    Baars, J.J.P.; Rutjens, A.J.; Mumm, R.

    2011-01-01

    Sinds het voorjaar van 2006 komen op champignonteeltbedrijven met een zekere regelmaat infecties voor met een agressieve groene schimmel; Trichoderma aggressivum. De infectie treedt al op op de compostbedrijven, maar is op het moment waarop compost wordt uitgeleverd aan teeltbedrijven nog niet

  16. Legitimacy in European nature conservation policy : case-studies in multilevel governance

    NARCIS (Netherlands)

    Keulartz, Jozef; Leistra, G.R.

    2008-01-01

    Natura 2000 was tot voor kort vorral een ecologisch-bestuurlijk project, maar de invoering roept ook kritiek en verzet op vanwege belangrijke sociale implicaties. Natura 2000 lijkt een legitimiteitsprobleem te hebben. De twee peilers onder de legitimiteit zijn de overheid (nationaal en die van de Un

  17. Container Monitoring Device (case)

    NARCIS (Netherlands)

    Maas, A.; Ruijsbroek, W.G.J.

    2015-01-01

    Stage Gate 11 is een bedrijf dat technologische innovaties naar de markt brengt. De drie ondernemers hebben een nieuw product ontwikkeld, de Container Monitoring Device, een product dat stalen containers ‘smart’ maakt door er allerlei sensoren aan te koppelen. Maar waar ligt precies de toegevoegde w

  18. Succesvol interim-management : Meesterschap in een tijdelijke context

    NARCIS (Netherlands)

    Schaveling, J.

    2010-01-01

    Als flexibele optie om het management van organisaties aan te vullen, past interim-management helemaal in deze tijd. Maar wat maakt een interim-managementopdracht succesvol? ‘Succesvol interim-management’ is een studie naar de succesfactoren van interim-management. In de literatuur worden verschille

  19. Scoren met interim-management : De weg naar tevreden opdrachtgevers

    NARCIS (Netherlands)

    Schaveling, J.

    2010-01-01

    Tegenwoordig kijkt niemand in organisaties meer op van de aanwezigheid van interim-managers. Interim-management biedt dé flexibiliteit om het management van organisaties aan te vullen. Maar wat maakt interim-managementopdrachten succesvol? Daarover gaat 'Scoren met interim-management: de weg naar te

  20. Cooperparen van een elektron en een gat

    NARCIS (Netherlands)

    Versteegh, M.A.M.; van Lange, A.J.; Stoof, H.T.C.; Dijkhuis, J.I.

    2013-01-01

    Cooperparen kennen we als paren van elektronen in een supergeleider. In dit artikel beschrijven we onze waarneming van Cooperparen van een elektron en een gat. Deze elektron-gat-Cooperparen komen niet voor in supergeleiders, maar wel in halfgeleiders. Onder sterke excitatie van de halfgeleider zinko

  1. Interview; kunst of kliederen; “De ene graffiti is de andere niet”

    NARCIS (Netherlands)

    Keus, R; Vanderveen, G.N.G.

    2010-01-01

    De aanpak van graffiti staat bij veel gemeenten hoog op de agenda. Het tegengaan van overlast en verloedering is hierbij meestal de belangrijkste reden. Maar om een aanpak echt te laten slagen, moet er volgens onderzoekster Gabry Vanderveen eerst goed worden nagegaan welke vormen van graffiti voor o

  2. Smaakvervlakking biedt productontwikkelaars kansen

    NARCIS (Netherlands)

    Lankveld, J.M.G.

    2005-01-01

    In dit dossier aandacht voor: Verslag van het jubileumcongres van CSK food enrichment over 'zuivel en smaak' in september 2005 in Leeuwarden. Smaak en geur, maar ook gevoel, uiterlijk en geluid bepalen de zintuiglijke beleving van een voedingsmiddel. Belangrijk is dat deze kenmerken bij productontwi

  3. Le miroir de la France : Johan Huizinga et les historiens français

    NARCIS (Netherlands)

    Voogd, Christophe Nicolaas de

    2013-01-01

    Het werk van Johan Huizinga (1872-1945) heeft al vroeg aandacht en weerklank gevonden bij Franse historici. Huizinga's Herfsttij der Middeleeuwen vond onmiddellijk na de publicatie ervan in het Duits bewondering maar ook kritiek. De Franse vertaling verscheen in 1932 en wordt er nog altijd herdrukt.

  4. De kwaliteit van beoordelingen door simulatiepatiënten in een Objective Structured Clinical Examination (OSCE): Een analyse van interbeoordelaarsovereenstemming

    NARCIS (Netherlands)

    Pelgrim, E.A.M.; Denessen, E.J.P.G.; Hettinga, A.M.; Postma, C.T.

    2009-01-01

    Inleiding: In deze studie staat de kwestie centraal of simulatiepatiënten, die getraind zijn in het spelen van de rol van patiënt tijdens examens maar niet medisch geschoold zijn, in staat zijn kandidaten bij een stationsexamen te beoordelen. De context waarbinnen dit onderzoek plaatsvond was de toe

  5. Erosie van rivieroevers

    NARCIS (Netherlands)

    Mosselman, E.

    1987-01-01

    Oevers staan sinds kart in het middelpunt van de belangstellingbij beheerders van oppervlaktewateren in Nederland. Niet langerbeschouwt men oevers slechts als randverschijnsel, maar alsobjecten met een duidelijk eigen plaats en functie.Het streven om te komen tot een integraal waterbeleid

  6. Rare jongens, die ICT'ers

    NARCIS (Netherlands)

    Thiadens, Th.J.G.

    2009-01-01

    Voor de aanleg van een tegelvloer in huis betaal je de tegelzetter een fors bedrag. Maar dan nog zou de opdrachtgever in het contract van tevoren expliciet schriftelijk moeten vastleggen dat hij de nieuwe tegelvloer in eigendom krijgt, anders heeft hij slechts gebruiksrecht.

  7. Strooisels in de paardenhouderij en arbeidsverbruik bij instrooien en uitmesten : onderzoek op het Paardenproefbedrijf te Brunssum en de Waiboerhoeve te Lelystad = Experiments on the use of litter and the labour requirement of mucking out stables in horse husbandry

    NARCIS (Netherlands)

    Smolders, E.A.A.; Giesen, J.H.J.

    1986-01-01

    In de paardenhouderij wordt het uitmesten als zwaar en onaangenaam werk ervaren, maar over de arbeidsbehoefte ervan zijn weinig exacte gegevens bekend. Daarom is onderzoek uitgevoerd met in totaal 60 rijpaardmerries en 12 draverruins, gehuisvest in boxen van 3 x 3 m en 1,5 x 3 m met gedeeltelijk roo

  8. Stakeholderengagement en stakeholderdialoog

    NARCIS (Netherlands)

    Elving, W.J.L.; Kok, D.; de Voogd, E.

    2015-01-01

    Sociale media vragen om een nieuwe vorm van dialoog en engagement van je stakeholders. Daar zitten voordelen aan, maar uiteraard kent verregaande interactie op digitale media ook veel gevaren. In dit hoofdstuk koppel ik sociale media aan stakeholder engagement en stakeholderdialoog. Daarbij kijk ik

  9. Celwandverteerbaarheid: hoe belangrijk is het?

    NARCIS (Netherlands)

    Groten, J.A.M.

    2010-01-01

    "De maïsrassenlijsten van de afgelopen dertig jaar zijn kolder en kunnen we het beste weggooien." Maïszadenleverancier KWS schopt tegen de huidige manier van classificeren van maïs. Maar is het werkelijk zo slecht gesteld met de Aanbevelende Rassenlijst?

  10. Strategische marketing : De tien geboden van het gezonden verstand

    NARCIS (Netherlands)

    Moenaert, R.K.; Robben, M.

    2007-01-01

    Door de jaren heen is de klassieke strategische doctrine nogal eens ter discussie gesteld. En het boek ‘Blue Ocean Strategy’ versterkt die trend alleen maar. In het boek staat waarde-innovatie centraal en het biedt, in tegenstelling tot eerdere werken zoals het pamflettistisch-kritische betoog van M

  11. Aanslagen VS geen vorm van nieuw terrorisme : tegen terreur met simpele middelen kan veiligheidsdienst weinig doen

    NARCIS (Netherlands)

    Teszelszky, Roger; Maat, Johri H.

    2001-01-01

    Politici en media spreken sinds de aanslagen in de Verenigde Staten van het "nieuwe terrorisme". Begrijpelijk, want de gebeurtenissen in de Verenigde Staten en vooral in New York zijn van een nieuwe orde. Toch is het terrorisme dat zich daar heeft gemanifesteerd niet nieuw, maar 'slechts' een extrem

  12. Crowdsourcing

    NARCIS (Netherlands)

    Vliet, Harry van; Brussee, Rogier; Hekman, Erik; Swart, Dick; Rovers, Michiel

    2013-01-01

    In dit boekje over crowdsourcing worden een aantal relevante aspecten van crowdsourcing behandeld. Allereerst beschrijven we een aantal historische voorbeelden om duidelijk te maken dat crowdsourcing niet ontstaan is als gevolg van de opkomst van internet maar als fenomeen al bestond voor het intern

  13. Agressief en hardnekkig

    NARCIS (Netherlands)

    Baars, J.J.P.; Rutjens, A.J.

    2007-01-01

    De champignonteelt ondervindt sinds 2006 hardnekkige problemen met Trichoderma soorten. Tot dan werden infecties met Trichoderma gezien als bijzonder vervelend voor wie het betrof, maar niet als een structureel probleem. Er is dus een trendbreuk opgetreden. Wat is er in hemelsnaam veranderd?

  14. De waarde van monitoring en evaluatie

    NARCIS (Netherlands)

    Vogelezang, J.V.M.; Wijnands, F.G.

    2008-01-01

    Alleen door ingrijpende vernieuwingen kan de landbouw echt verduurzamen. Innovatie-experimenten leveren daar een belangrijke bijdrage aan. Maar is de bijdrage aan het veranderingsproces wel te meten, en hoe en wat meet je dan? En is het mogelijk leerinstrumenten te ontwikkelen die het succes van

  15. Stimuleren om te inhiberen. Over de geschiedenis van de nervus vagus stimulatie behandeling

    NARCIS (Netherlands)

    Eling, P.A.T.M.; Renier, W.O.

    2013-01-01

    Meestal wordt gedacht dat te veel prikkels leiden tot een epileptische aanval. Waarom dan stimuleren? Bij nervus vagus stimulatie wordt inderdaad geprikkeld, maar het doel is dat daardoor het optreden van een aanval wordt afgeremd. In dit essay gaan we in op de historische achtergronden van deze beh

  16. Tussen God en gekte. Een studie over zekerheid en symbolisering in psychose en geloven.

    NARCIS (Netherlands)

    Ypma, Sytze

    2001-01-01

    De centrale vraagstelling van dit onderzoek luidt: wat leert de bestudering van de psychose ons over zekerheid en symbolisering in het geloven? Dit onderzoek richt zich daarmee niet zozeer op de inhoudelijke verwantschap tussen de voorstellingswerelden in psychose en geloven, maar op het specifieke

  17. Korte verblijftijd haalbaar bij mestvergisting

    NARCIS (Netherlands)

    Timmerman, M.; Eekert, M.; Riel, van J.W.; Schuman, E.

    2013-01-01

    Vergisting van mest bij verblijftijden van korter dan 15 dagen is haalbaar, maar mestsoort en mestkwaliteit blijken een groot effect te hebben op de biogasproductie bij deze korte verblijftijden. Het is mogelijk om bij deze korte verblijftijd een kleine hoeveelheid (<5%) glycerine toe te voegen w

  18. De smaak is raak

    NARCIS (Netherlands)

    Noorduyn, L.; Verkerke, W.

    2009-01-01

    Een goede smaak van biologische producten kan helpen de afzet structureel te vergroten. Daarbij is niet alleen de technische smaak van belang, maar ook of het product voldoende aansluit bij de beleving van de consument. Zeker als het om de 'light users' gaat

  19. Internetmarkten: wie profiteert?

    NARCIS (Netherlands)

    M.C.W. Janssen (Maarten); J.L. Moraga-Gonzalez (José Luis)

    2000-01-01

    textabstractEconomen lijken het er over eens dat het internet positieve welvaartseffecten kan hebben. Maar of het werkelijk de mogelijkheden biedt om tot een perfecte markt te komen, blijft de vraag. Werpt het internet geen nieuwe barrières op? En aan wie valt de extra welvaart toe? Over visionairs

  20. Snelstartgids voor preventiemedewerkers

    NARCIS (Netherlands)

    Anonymous

    2015-01-01

    Als preventiemedewerker houd je je bezig met veilig en gezond werken in jouw organisatie. Maar wat houdt dat precies in? En hoe begin je? In deze Snelstartgids voor preventiemedewerkers vind je antwoord op deze vragen, met praktische tips, checklists en verwijzingen naar handige websites en tools.

  1. De preventiemedewerker op maat van gemeenten : handreiking voor invoering van preventietaken voor de alledaagse zorg voor veiligheid en gezondheid naar aanleiding van de wijziging Arbowet juli 2005

    NARCIS (Netherlands)

    Kwantes, J.H.

    2005-01-01

    De werkgever en de OR spelen een sleutelrol bij het vaststellen van de preventietaken. Deze handreiking is daarom geen blauwdruk, maar wijst op de overwegingen en aandachtspunten die van belang zijn om een juiste keuze te maken. Een keuze die aansluit bij de bestaande risico's en het bestaande arbob

  2. MOOCs; vanwaar al die ophef?

    NARCIS (Netherlands)

    Henderikx, Maartje; Kreijns, Karel

    2016-01-01

    MOOCs; vanwaar die ophef? Het nog maar zeer recente fenomeen MOOCs (massive open online courses) heeft zich in korte tijd al een onwrikbare positie weten in te nemen in het open online onderwijs. De hype rondom deze nieuwe manier van onderwijs geven bereikte zijn hoogtepunt in 2012, dat prompt werd

  3. Hoe ontwerpt u een effectieve MOOC? Voorbeelden uit de praktijk

    NARCIS (Netherlands)

    Firssova, Olga; Brouns, Francis

    2016-01-01

    Wat is kenmerkend voor het design van Massive Open Online Courses (MOOCs)? Wat maakt ontwerpen van MOOCs bijzonder uitdagend maar ook bijzonder interessant? In de workshop over MOOC Ontwerp gaat u actief op zoek naar antwoorden aan de hand van ervaringen met het ontwerpen en uitleveren van MOOCs in

  4. Closing the loop : optimal strategies for hybrid manufacturing /remanufacturing systems

    NARCIS (Netherlands)

    Caner Bulmus, Serra

    2013-01-01

    Serra Caner Bulmus beschrijft in haar proefschrift optimale strategieën voor inzameling van gebruikte producten en herfabricage van die producten door bedrijven. Bij herfabricage worden niet alleen de materialen hergebruikt, maar wordt ook de toegevoegde productiewaarde behouden. Daarmee is herfabri

  5. De acceptatie van innovaties in de context van een netwerksamenleving

    NARCIS (Netherlands)

    Hillebrand, B.; Driessen, P.H.; Kok, R.A.W.

    2010-01-01

    De acceptatie van nieuwe producten is in de literatuur uitgebreid bestudeerd. Maar er is weinig aandacht besteed aan de acceptatie van nieuwe producten in de context van een netwerksamenleving. In een netwerksamenleving hangt de acceptatie van een nieuw product niet alleen af van de bereidheid van k

  6. The network is the message

    NARCIS (Netherlands)

    Thijs Waardenburg; Dr. Gerrita van der Veen; Dr. Lotte M. Willemsen; Rogier Brussee

    2016-01-01

    Veel bedrijven staan reeds via social media als Facebook of Twitter in contact met hun gebruikers en iedere serieuze marketingcampagne werkt tegenwoordig met likes en tweets. Hoeveel ze daarin investeren en in de toekomst willen blijven doen, hangt af van de effectiviteit van social media. Maar wann

  7. De beleidswijziging levenslange gevangenisstraf : Of: de nieuwe kleren van de staatssecretaris

    NARCIS (Netherlands)

    van Hattum, Wiene

    2016-01-01

    De staatssecretaris slaagt er met zijn onlangs gepresenteerde beleidswijziging voor de tenuitvoerlegging van de levenslange gevangenisstraf niet in deze straf EVRM-proof te maken, integendeel. De rechtspositie van de levenslanggestrafte wordt alleen maar verslechterd. Dat betekent enerzijds dat de s

  8. Te hard van stapel gelopen.

    NARCIS (Netherlands)

    W-J. Verhoeven (Willem-Jan)

    2008-01-01

    textabstractHoe goed we ook trachten de samenleving te organiseren, fraude maakt er deel van uit. Dit blijkt uit spraakmakende grote schandalen zoals de Enron-zaak, de Bouwfraude-zaak en de Nigerian letter scams. Maar fraude komt ook op minder geruchtmakende schaal voor, zoals oplichting op veilings

  9. De redenloze consument

    NARCIS (Netherlands)

    dr. A. Maas

    2013-01-01

    Marketers moeten klantenbehoeften vervullen. Zij werken klantgericht en baseren zich daarbij vaak op enquêtes en andere verbale uitingen van klanten. Vanuit de psychologie is inmiddels echter duidelijk dat mensen vaak helemaal niet zeggen wat ze echt vinden. Niet omdat ze dat niet willen, maar omdat

  10. Een klok doet geen "pok"

    NARCIS (Netherlands)

    Engelen, Johan

    2010-01-01

    Debakel, fiasco, mislukking. Het zijn dagelijkse bezigheden voor ons onderzoekers. Je kan er dus maar beter mee leren omgaan. Veel mensen hebben zich uitgesproken over hun tevredenheid met mislukkingen. Bijvoorbeeld Albert Einstein’s “Anyone who has never made a mistake has never tried anything new.

  11. Immature dengue virus : functional properties and potential contribution to disease

    NARCIS (Netherlands)

    Da Silva-Voorham, Júlia Maria

    2013-01-01

    Beter inzicht in mechanismen achter infectieziekte dengue Dengue (‘knokkelkoorts’) is een veelvoorkomende, tropische infectieziekte die wordt overgebracht door muggen. Naar schatting raken jaarlijks zo’n vijftig tot honderd miljoen mensen besmet. Meestal gaat dengue vanzelf over, maar in zo’n

  12. Kraamkamer van duurzaamheid : de innovatieve kracht van biologische landbouw voor verduurzaming van de gangbare landbouw

    NARCIS (Netherlands)

    Teenstra, E.D.

    2004-01-01

    Velen dichten de biologische landbouw een grote rol toe in de verduurzaming van de gangbare landbouw. Maar hoe groot is nu die innovatieve kracht van de biologische landbouw en welke invloed heeft dit op een aantal duurzaamheidthema’s? Dit zijn de vragen waarop deze publicatie een antwoord geeft. De

  13. Stoomcursus Europees beleid

    NARCIS (Netherlands)

    Silvis, H.J.

    2008-01-01

    Mensen meer laten begrijpen van de Europese Unie. Dat willen de auteurs van het boek EU-beleid voor landbouw, voedsel en groen. "Er is veel onbegrip over de EU", zegt Huib Silvis, één van de samenstellers, "maar we kunnen niet zonder. Zaken als de voedselvoorziening, milieu en natuur ontstijgen nou

  14. Innovatie in de digital age....

    NARCIS (Netherlands)

    Reep, Frans van der

    2013-01-01

    1e alinea column: Hoe ziet innovatie in de digital age eruit? Anders dan daarvoor? Is succes van innovatie in de digital age wel voorspelbaar? Bestaat er zoiets als een business logica voor innovatie? Voor echt nieuwe business is dat maar heel beperkt zo. Er zijn geen marktvoorbeelden waar je naar k

  15. Advances in digital chest radiography: impact on reader performance

    NARCIS (Netherlands)

    De Boo, D.W.

    2012-01-01

    Digitalisering binnen de radiologie heeft de nodige verbeteringen opgeleverd, onder andere voor de longfoto. Vroege stadia van longkanker en kleine uitzaaiingen naar de longen worden geregeld gemist op scans, maar computerprogramma’s kunnen deze gemiste afwijkingen soms wel detecteren. De programma’

  16. Column: lef

    NARCIS (Netherlands)

    Reep, Frans van der

    2012-01-01

    1e alinea column: Ook in je beleggingsbeslissingen is het voor echte performance wellicht tijd om eens voorbij best practices (dan word je namelijk hoogstens tweede) te kijken naar next practices. Als je op zeker speelt, verdien je weinig geld. Want anderen gingen je al voor. Maar kun je nog meer op

  17. Die mites rondom die val van Troje en Vergilius se uitbeelding daarvan in die tweede boek van die Aeneïs

    Directory of Open Access Journals (Sweden)

    J. Swanepoel

    1981-05-01

    Full Text Available Die mites oor die val van Troje vertel ’n aangrypende verhaal en in die tweede boek van die Aeneïs gee Vergilius op ’n besondere wyse gestalte daaraan. Maar Vergilius se vergestalting daarvan is slegs een van die variante van die verhaal.

  18. Metateks ('n Vakfilosofiese vergelyking van twee analises van ‘Droogte’ van Leon Strydom

    Directory of Open Access Journals (Sweden)

    J. Swanepoel

    1984-05-01

    Full Text Available In hierdie artikel sal twee analises van Leon Strydom se gedig “Droogte” uit ’n vakfilosofiese hoek met mekaar vergelyk word. Die analises is uitgevoer deur dr. G.F.T. Kuschke en prof. Ina Grähe, albei opgeleide literatore, maar wetenskaplikes wal die literatuur uit verskillende denkraamwerke benader.

  19. Patronen doorbreken in het Amsterdamse Jeugddomein

    NARCIS (Netherlands)

    Metze, T.A.P.; van den Berg, Douwe; Hafkamp, Wim; Koffijberg, Jos; Rutjens, Ton; Teisman, Geert

    2015-01-01

    In juli 2007 besloot Lodewijk Asscher, toen wethouder in Amsterdam, een onderzoek in te stellen naar de mazen in het ‘systeem’ van de jeugdzorg. Dit naar aanleiding van aangrijpende incidenten waarbij veel hulpverleners betrokken waren. Het onderzoek, ‘Operatie Frankenstein’ genoemd maar met de offi

  20. CQ-index Stomazorg: kwaliteit van de stomazorg in Nederlandse ziekenhuizen vanuit het perspectief van patiënten.

    NARCIS (Netherlands)

    Triemstra, M.; Asmoredjo, J.

    2013-01-01

    Mensen met een stoma zijn positief over de zorg. Zij beoordelen de stomazorg gemiddeld met een 8,6. De stomazorg is beter dan tien jaar geleden. Maar er zijn duidelijke verschillen tussen ziekenhuizen. Wat vinden mensen met een stoma belangrijk in de zorg die ze krijgen in een ziekenhuis? Wat zijn

  1. Biozuiveringssystemen voor de open teelten : stand van zaken van onderzoek 2009

    NARCIS (Netherlands)

    Wenneker, M.; Beltman, W.H.J.; Lans, van der A.; Weide, van der R.Y.; Werd, de H.A.E.

    2010-01-01

    In dit project werd gezocht naar zuiveringssystemen voor de verwerking van restwater die gemakkelijk op bedrijven zijn te implementeren. Daarbij is voor agrariërs belangrijk dat de systemen goedkoop en betrouwbaar zijn, met een minimum aan arbeid, maar hoog rendement.

  2. Miljoenennota 2012 zwijgt over cybercrime

    NARCIS (Netherlands)

    Reep, Frans van der

    2011-01-01

    1e alinea column: De Miljoenennota 2012 zwijgt over cybercrime. Ik kan je verzekeren dat het onderwerp, na het Diginotar-debacle, wel snel weer op de agenda komt. Nog voordat er een oplossing is. Het bestuurlijk en wettelijk kader, maar ook het besef van de omvang van cybercrime, passen zich onvoldo

  3. Process Control Security in het Informatieknooppunt Cybercrime NICC : Eén publiekprivate geïntegreerde aanpak. Eén sluitende nationale infrastructuur ter bestrijding van cybercrime.

    NARCIS (Netherlands)

    Luiijf, H.A.M.

    2009-01-01

    Opsporing en vervolging van cybercrime? Heel belangrijk, maar niet dé oplossing voor het probleem. Voorkómen is beter! De sectoren die zijn aangesloten op het Informatieknooppunt Cybercrime hebben de (informatie)beveiliging van procescontrolesystemen (PCS), waaronder SCADA, als uitdaging opgepakt. D

  4. Samen tegen cybercrime, een aanpak die werkt

    NARCIS (Netherlands)

    Zielstra, A.; Ali, M.; Luiijf, H.A.M.

    2008-01-01

    Opsporing en vervolging van cybercrime is nodig, maar niet dé oplossing om veilig digitaal te kunnen werken. Alleen als overheid en bedrijfsleven de handen ineenslaan en informatie over dreigingen uitwisselen, wordt het mogelijk cybercriminelen een stap voor te blijven. In Nederland hebben overheid

  5. Bad-Ass Librarians en Guerilla Archivists : Amerikaans activisme onder Trump

    NARCIS (Netherlands)

    Bakker, Marjo

    In de eerste honderd dagen van Donald Trumps presidentschap vonden niet alleen in Amerikaanse steden maar ook wereldwijd massale protesten plaats tegen zijn uitlatingen en voorgenomen beleid. Denk bijvoorbeeld aan de Women’s March op 21 januari, de March for Science op 22 april, de People’s Climate

  6. Akoepedie voor auditors?

    NARCIS (Netherlands)

    K.I. Mollema (Kornelis)

    2008-01-01

    textabstractBinnen audit en accountancy heeft men de controle van de informatietechnologie (IT) te lang overgelaten aan specialisten (IT-auditors). Maar inmiddels is de IT te zeer het kloppend hart van de onderneming om haar nog langer te negeren, stelt Mollema. Door de toenemende frequentie en snel

  7. Oosterschelde geschikt als habitat voor bruinvis?

    NARCIS (Netherlands)

    Jansen, O.E.; Aarts, G.M.; Reijnders, P.J.H.

    2013-01-01

    Sinds tientallen jaren zijn er weer meer bruinvissen waargenomen in de Noordzee rond Nederland. De dieren drongen onlangs ook door in estuaria, zoals de Oosterschelde. Maar is het habitat in de Oosterschelde eigenlijk wel geschikt voor de bruinvis en is er voldoende voedselaanbod en rust? En welke i

  8. Mogelijkheden voor verder herstel van fauna in rivieruiterwaarden

    NARCIS (Netherlands)

    Lange, de H.J.; Noordijk, J.; Nijssen, M.

    2014-01-01

    In het Nederlandse rivierengebied zijn de afgelopen decennia veel natuurontwikkelingsprojecten uitgevoerd, geïnspireerd door Plan Ooievaar. Er zijn voor de fauna zeker successen te melden, maar sommige soorten hebben het nog steeds zeer moeilijk of zijn nog niet teruggekeerd. In dit artikel beschrij

  9. Foodtopia : het voedsel van de toekomst

    NARCIS (Netherlands)

    Govers, F.; Boekel, van T.; Buiter, R.

    2015-01-01

    Van gekookte en luchtdicht verpakte producten tot sterk geconcentreerde voedingsmiddelen; in de afgelopen eeuwen hebben diverse innovaties ons voedsel veiliger, langer houdbaar en beter beschikbaar gemaakt. Maar ook al lijkt het voedsel in de westerse wereld nu overvloedig en gevarieerd voor handen,

  10. Verlenging groeiseizoen grasland

    NARCIS (Netherlands)

    Visscher, J.

    2010-01-01

    Verlenging van het groeiseizoen van grasland betekent meer grasgroei in het late najaar, maar ook een vroegere groei in het voorjaar. Bemesting, grassoorten, graslandgebruik en stoppelgewassen bieden hiervoor mogelijkheden. Het graslandgebruik is van invloed op de benutting van het geproduceerde gra

  11. Oogstschadeverzekering in de belangstelling

    NARCIS (Netherlands)

    Meer, van der R.W.

    2007-01-01

    Een brede weersverzekering waarmee niet alleen het risico op oogstschade door hagel, storm of wateroverlast, maar ook door vorst, droogte of sneeuw wordt afgedekt, bestaat reeds in diverse Europese landen. Uit een recentelijk gehouden enquête onder akkerbouwers blijkt dat zo’n verzekering ook in Ned

  12. Ontwikkeling van de sojateelt in Noord Nederland

    NARCIS (Netherlands)

    Timmer, R.D.; Visser, de C.L.M.

    2014-01-01

    In Europa wordt voor non-GMO soja een premie betaald van zo'n 150 euro per ton. Dit geldt voor soja voor de humane voeding zoals sojadrinks en vleesvervangers. Het volume van deze markt is beperkt, maar in Hamburg staat een fabriek die graag Nederlandse soja koopt terwijl inmiddels ook een Nederland

  13. Confrontatie met de slachtoffers: Nazi-Duitsland en de jodenvervolging [Review of: S. Friedländer Nazi-Duitsland en de joden

    NARCIS (Netherlands)

    Melching, W.

    2008-01-01

    Historicus Melching beoordeelt het boek Nazi-Duitsland en de joden van Saul Friedländer op zijn merites. Friedländers historische visie op de holocaust en Hitler is tamelijk gangbaar en niet origineel, ontdekt Melching, maar ‘door het intensieve gebruik van primaire bronnen is de wijze waarop hij he

  14. Kostprijzen tomaat, komkommer en paprika in Nederland en Spanje

    NARCIS (Netherlands)

    Verhaegh, A.P.

    1998-01-01

    De productiekosten van losse tomaten bedragen in Spanje ongeveer de helft van die in Nederland. Vooral de toonaangevende en grote bedrijven in Murcia en de moderne maar veel kleinere bedrijven in Almeria kunnen tegen lage kosten telen. De afzetkosten naar de West-Europese markt zijn voor Spanje fors

  15. Niets doen loont bij Jakobskruiskruidplaag

    NARCIS (Netherlands)

    Bezemer, T.M.; Putten, van der W.H.; Rienks, F.

    2006-01-01

    Via het hooi veroorzaakt jakobskruiskruid in toenemende mate problemen voor het vee. Ook in natuurontwikkelingsgebieden komt de plant veelvuldig voor, maar verdwijnt dan ook op den duur vanzelf weer. Dit wordt meestal in verband gebracht met de verzuring van de bodem. Nieuw onderzoek laat echter zie

  16. Van bricks tot clicks in de mix: navigatie-strategie als basis voor multi-channelmanagement

    NARCIS (Netherlands)

    Veen, Gerrita van der; Ossenbruggen, Robert

    2013-01-01

    Veel bedrijven stemmen hun communicatie en interactie met de consument af door te segmenteren op kanaalgebruik. In deze studie tonen wij aan dat een focus op kanalen maar zeer beperkt bruikbaar is. Deze beperking is een logisch gevolg van het feit dat de meeste consumenten meerdere kanalen gebruiken

  17. Recht voor big data, big data voor recht

    NARCIS (Netherlands)

    Lafarre, Anne

    Big data is een niet meer weg te denken fenomeen in onze maatschappij. Het is de hype cycle voorbij en de eerste implementaties van big data-technieken worden uitgevoerd. Maar wat is nu precies big data? Wat houden de vijf V's in die vaak genoemd worden in relatie tot big data? Ter inleiding van

  18. Big data is de hype voorbij: Nieuwe regelgeving leidt tot realistischer beeld

    NARCIS (Netherlands)

    van Eijk, N.

    2016-01-01

    Big data leek een synoniem voor gouden bergen. Maar door nieuwe wetgeving wordt de betekenis ervan behoorlijk genuanceerd. Een betoog over de (on)mogelijkheden van big data aan de hand van de meldplicht datalekken en het gebruik van data door inlichtingen- en veiligheidsdiensten.

  19. Sound Souvenirs : Audio Technologies, Memory and Cultural Practices

    NARCIS (Netherlands)

    2009-01-01

    Herinneringen halen we niet alleen op aan de hand van beelden, maar ook met behulp van geluid. We koesteren onze versleten bandrecorderspoelen, cassettebandjes en langspeelplaten - onze "sound souvenirs" - om de muziek van vroeger nog eens te horen. Radioprogramma's als de Top2000 houden oude nummer

  20. Luchtverontreinigende emissies onder controle?

    NARCIS (Netherlands)

    Verbeek, R.P.; Smokers, R.T.M.

    2011-01-01

    De luchtverontreinigende emissies van vrachtauto's en binnenvaartschepen moeten aan steeds strengere eisen voldoen. Daardoor zullen de emissies van nieuwe voer- en vaartuigen in 2020 nog maar een fractie zijn in vergelijking tot bijvoorbeeld 1990. Werkt het allemaal goed in de praktijk? En heeft het

  1. Onderzoek naar bemesting als mogelijke oorzaak voor verfijning in Crocus

    NARCIS (Netherlands)

    Leeuwen, van P.J.; Trompert, J.P.T.

    2005-01-01

    Verfijning in Crocus is een verschijnsel waarbij de nieuwe knollen op de oude knol niet uitgroeien tot leverbare maten. Het is dus geen echte verfijning waarbij de vermeerdering sterk toeneemt, maar het niet uitgroeien van knollen. Vaak blijven na het rooien de nieuwe knollen vast zitten op de oude

  2. Ethnicity in the Caribbean : Essays in Honor of Harry Hoetink

    NARCIS (Netherlands)

    Oostindie, Gert

    2005-01-01

    Het'Amsterdam Academic Archive is een initiatief van Amsterdam University Press. In de serie verschijnen (populair-)wetenschappelijke publicaties die niet meer leverbaar zijn, maar waarnaar nog wel vraag is in binnen- en buitenland. Relevante delen van deze publicaties zijn ook in te zien in het rep

  3. Draadloze ondergang van een bedrijf

    NARCIS (Netherlands)

    Degen, A.J.G.

    2003-01-01

    Draadloze netwerken zijn meer dan een rage. Ze bieden netwerktoegang onafhankelijk van kabelaansluitingen, wat bijvoorbeeld zorgt voor flexibiliteit qua werkplekken. Bedrijven kunnen zodoende heel wat besparen op de aanlegkosten voor hun intranet en interne verhuiskosten. Maar hoe zit het met de bev

  4. Reumaatjes@work De invloed van een gedragsinterventie op de mate van self-efficacy bij kinderen met JIA

    NARCIS (Netherlands)

    Lodder, A. J. T.

    2013-01-01

    Samenvatting Juveniele Idiopathische Artritis (JIA) is een chronische heterogene auto-immuunziekte die zich openbaart bij kinderen voor het 16e levensjaar. Het heeft niet alleen invloed heeft op de fysieke gesteldheid van patiënten, maar brengt ook psychosociale problemen met zich mee. Het intervent

  5. BEPS: quo vadis Nederland?

    NARCIS (Netherlands)

    Cornelisse, R.P.C.

    2015-01-01

    Schrijver blikt vooruit op de ontwikkelingen die dit jaar in de fiscale wereld gaan plaatsvinden. Hij stelt de vraag aan de orde of Nederland de ontwikkelingen op dit terrein moet afwachten of dat het verstandiger is juist niet af te wachten maar pro-actief haar fiscale stelsel op korte termijn zoda

  6. Olaf van Kooten, hoogleraar Wageningen UR en lector InHolland: ‘hoezo slechte markt; we zijn zelf de markt’

    NARCIS (Netherlands)

    Kierkels, T.; Kooten, van O.

    2014-01-01

    Er is iets grondig mis in de afzetketen van met name groente en fruit; de samenwerking komt maar moeilijk van de grond. Als gevolg daarvan liggen er producten van een lage kwaliteit in de winkel en verdient niemand iets. Dat het anders kan bewijzen schaarse voorbeelden. Hoogleraar tuinbouwketens Ola

  7. De geest in dit huis is liefderijk: het leven en De Werkplaats van Kees Boeke (1884-1966)

    NARCIS (Netherlands)

    Hooghiemstra, D.A.

    2013-01-01

    De christen-pacifist Kees Boeke (1884-1966) wordt wel ‘onderwijshervormer’ genoemd maar hij beoogde niet minder dan de stichting van een nieuwe wereld. Toen de poging om die gemeenschap te stichten mislukte, besloot Boeke een school te stichten waar de ‘nieuwe wereld’ van de grond af opgebouwd moest

  8. Glutenvrije oergranen sluiten aan bij gezondheidtrend

    NARCIS (Netherlands)

    Janssens, S.R.M.

    2008-01-01

    Er liggen kansen voor de productie van glutenvrije oergranen in Nederland, maar deze liggen niet zozeer bij mensen met een glutenvrij dieet. De keten kan het beste inspelen op de huidige trends gezondheid en authenticiteit, waarmee ze een bredere doelgroep aanspreekt. Dit blijkt uit een verkenning d

  9. Dokter Google

    NARCIS (Netherlands)

    Kruisinga, F.H.; Huibers, Theo W.C.; Kuijpers, T.W.

    2007-01-01

    Het internet is een rijke maar onbetrouwbare bron van informatie. Daarom beperken artsen zich bij het zoeken naar informatie meestal tot een beperkt en gecontroleerd domein. Door de kracht van zoekmachines echter optimaal te benutten kan op een effectieve manier toegang worden verkregen tot

  10. Casus: behandeling in het buitenland. If you pay peanuts...

    NARCIS (Netherlands)

    F. van der Weijden

    2015-01-01

    Tandartsen in Ierland hebben vorig jaar de noodklok geluid, omdat een groeiend aantal patiënten verminkt terugkomt van tandartsbehandelingen in het buitenland. Een onderwerp waar tandartsen in Nederland ook tegenaan lopen, maar waar weinig over wordt geschreven. In dit artikel een casus uit mijn eig

  11. Napoleon : Voor en tegen in de Franse geschiedschrijving

    NARCIS (Netherlands)

    Geyl, Pieter C.A.

    2006-01-01

    Wie was Napoleon? Over die vraag werd door Franse historici al tijdens zijn leven (1769-1821) gediscussieerd. Na zijn dood nam de discussie alleen maar toe. Was Napoleon een machtswellusteling en een tiran? Of bezorgde Napoleon Europa de beginselen van de Franse Revolutie (vrijheid, gelijkheid en br

  12. Plastic zonder olie : lesmodule voor nieuwe scheikunde

    NARCIS (Netherlands)

    Langejan, B.; Klein Douwel, C.; Horst, ter J.J.; Tijdink, K.; Marle, van N.; Klaasen, P.; Coolen, R.; Assenbergh, van P.; Sijbers, J.P.J.; Mast, A.

    2013-01-01

    Lesmodule voor nieuwe scheikunde voor leerlingen uit 5 en 6 vwo. Bioplastics worden gemaakt uit natuurlijke grondstoffen. Als ze de synthetische plastics vervangen kan de voorraad aardolie ontzien worden. Omdat veel bioplastics afbreekbaar zijn, kan ook de berg plastic afval krimpen. Maar zijn biopl

  13. Lintwormen bij schapen niet gauw gevaarlijk voor de mens

    NARCIS (Netherlands)

    Borgsteede, F.H.M.

    1997-01-01

    Schapen kunnen fungeren als tussengastheer van 4 lintwormsoorten die alle de hond als eindgastheer hebben. Een van deze 4 is ook gevaarlijk voor de mens, namelijk Echinococcus granulosus. het gevaar komt dan niet van het schaap, maar van de eindgastheer, de hond

  14. Nazomeren [redactioneel

    NARCIS (Netherlands)

    Wester, F.P.J.

    2016-01-01

    Als u dit leest, is het misschien wat moeilijk voorstelbaar, maar ik schrijf deze boodschap op een bijna tropische dag in september. Een bijzondere tijd, niet vanwege het weer, want in 1929 leer ik zojuist, was het in september ook al 34,4 graden Celsius. Ik weet niet hoe u daar achteraf tegen aanki

  15. Twitterende Bibliotheken: een praktische handreiking

    NARCIS (Netherlands)

    Brink, van den Wilma

    2011-01-01

    Twitter lijkt het nieuwe wondermiddel te zijn om in contact te komen en banden te smeden met de doelgroep. Het aantal bibliotheken dat daarom een Twitteraccount opent groeit hard. Maar worden de verwachtingen ook gehaald? Het artikel staat stil bij de wijze waarop bibliotheken en informatiespecialis

  16. Wat iedere journalist moet weten van marktonderzoek : Doorvragen bij wie

    NARCIS (Netherlands)

    de Leeuw, Edith

    2014-01-01

    Een gouden regel in de journalis-tiek vormen de vijf W’s (en een H). Een goede onderzoeksjournalist zal altijd vragen: wie, waarom, wat, waar, wanneer en hoe. Het zijn prima basisvragen, maar wanneer een journalist een item voorbereidt en daarbij gebruik maakt van marktonderzoek, moet er nog even do

  17. Van wie is de Mona Lisa? Over culturele identiteit en globalisering

    NARCIS (Netherlands)

    de Boer, T.; Groenhuijsen, M.; Hondius, E.; Soeteman, A.

    2014-01-01

    Kunstvoorwerpen hebben geen paspoort, maar kennelijk wel een nationaliteit. Sinds de 19e eeuw kent het recht de bescherming van het ‘nationaal erfgoed’, dat in beginsel behouden moet blijven voor het land waar het is ontstaan of waarvan de maker onderdaan was of is. Het is de vraag of dit

  18. Korte verblijftijd haalbaar bij mestvergisting

    NARCIS (Netherlands)

    Timmerman, M.; Eekert, M.; Riel, van J.W.; Schuman, E.

    2013-01-01

    Vergisting van mest bij verblijftijden van korter dan 15 dagen is haalbaar, maar mestsoort en mestkwaliteit blijken een groot effect te hebben op de biogasproductie bij deze korte verblijftijden. Het is mogelijk om bij deze korte verblijftijd een kleine hoeveelheid (<5%) glycerine toe te voegen w

  19. Artsen onder druk: Het kwaliteitsbeleid van de medische beroepen in Groot-Brittannië, Nederland en België tussen 1970 en 1996, als gevolg van de interne en externe druk op de zelfregulering van artsen.

    NARCIS (Netherlands)

    R. van Herk (Rudi)

    1997-01-01

    textabstractTot in de jaren zeventig werd de medische professie gezien als een beroepsgroep met een grote mate van gezag en professionele vrijheid, die haar kennis in dienst stelde van de belangen van patiënten en samenleving. Omdat de samenleving vanouds een groot belang aan gezondheid hecht, maar

  20. De strijd tegen eenzaamheid. Technologie als wondermiddel?

    NARCIS (Netherlands)

    MD E.J.M. Wouters; Dr. Sil Aarts

    2016-01-01

    De kranten stonden er de afgelopen jaren vol van. Krantenkoppen zoals “Meer ouderen digitaal; toename van tablet-en smartphonegebruik” (plusonline, 15 december 2014) en “Opa en Oma aan de Whatsapp” (telegraaf.nl, 3 oktober 2015). Maar welke rol kan technologie nu ECHT spelen in de strijd tegen