Institute of Geological science

Hanoi, Vietnam

Institute of Geological science

Hanoi, Vietnam
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Arndt J.E.,Alfred Wegener Institute for Polar and Marine Research | Schenke H.W.,Alfred Wegener Institute for Polar and Marine Research | Jakobsson M.,University of Stockholm | Nitsche F.O.,Lamont Doherty Earth Observatory | And 12 more authors.
Geophysical Research Letters | Year: 2013

The International Bathymetric Chart of the Southern Ocean (IBCSO) Version 1.0 is a new digital bathymetric model (DBM) portraying the seafloor of the circum-Antarctic waters south of 60°S. IBCSO is a regional mapping project of the General Bathymetric Chart of the Oceans (GEBCO). The IBCSO Version 1.0 DBM has been compiled from all available bathymetric data collectively gathered by more than 30 institutions from 15 countries. These data include multibeam and single-beam echo soundings, digitized depths from nautical charts, regional bathymetric gridded compilations, and predicted bathymetry. Specific gridding techniques were applied to compile the DBM from the bathymetric data of different origin, spatial distribution, resolution, and quality. The IBCSO Version 1.0 DBM has a resolution of 500 × 500 m, based on a polar stereographic projection, and is publicly available together with a digital chart for printing from the project website ( and at Key Points The first regional bathymetric compilation covering the entire Southern Ocean A new keystone dataset for Antarctic research The southern equivalent to IBCAO is now released ©2013. American Geophysical Union. All Rights Reserved.

Berger C.,Swiss Federal Institute of forest | Berger C.,Institute of Geological science | McArdell B.W.,Swiss Federal Institute of forest | Fritschi B.,Swiss Federal Institute of forest | Schlunegger F.,Institute of Geological science
Water Resources Research | Year: 2010

We describe a novel channel bed erosion sensor and the first results of its usage. The sensor is based on a resistance chain built into a column of 5 cm tall cylindrical aluminum elements. The timing and change in resistance as elements are removed from the column are logged outside of the channel. Five sensor columns were placed in the Illgraben torrent bed prior to the start of the 2008 flow season. Before the first debris flow event, 0.1 m of sediment was deposited by small flood events. During the 16 June 2008 debris flow, this layer was eroded, and erosion was therefore first measured 44 min after front arrival and took place progressively over the next 12 min. The results at the erosion sensors are consistent with measurements over the entire reach using traditional surveying methods, and data from the adjacent debris flow monitoring station provide a basis for interpretation. The main limitation is that this sensor records only the rate and timing of the maximum bed erosion and cannot be used to determine deposition and subsequent erosion within a given event. Copyright 2010 by the American Geophysical Union.

Bekaddour T.,Institute of Geological science | Schlunegger F.,Institute of Geological science | Attal M.,Institute of Geography | Norton K.P.,Victoria University of Wellington
Sedimentology | Year: 2013

Modern mixed alluvial-bedrock channels in mountainous areas provide natural laboratories for understanding the time scales at which coarse-grained material has been entrained and transported from their sources to the adjacent sedimentary sink, where these deposits are preserved as conglomerates. This article assesses the shear stress conditions needed for the entrainment of the coarse-bed particles in the Glogn River that drains the 400 km2 Val Lumnezia basin, eastern Swiss Alps. In addition, quantitative data are presented on sediment transport patterns in this stream. The longitudinal stream profile of this river is characterized by three ca 500 m long knickzones where channel gradients range from 0·02 to 0·2 m m-1, and where the valley bottom confined into a <10 m wide gorge. Downstream of these knickzones, the stream is flat with gradients <0·01 m m-1 and widths ≥30 m. Measurements of the grain-size distribution along the trunk stream yield a mean D84 value of ca 270 mm, whereas the mean D50 is ca 100 mm. The consequences of the channel morphology and the grain-size distribution for the time scales of sediment transport were explored by using a one-dimensional step-backwater hydraulic model (Hydrologic Engineering Centre - River Analysis System). The results reveal that, along the entire trunk stream, a two to 10 year return period flood event is capable of mobilizing both the D50 and D84 fractions where the Shields stress exceeds the critical Shields stress for the initiation of particle motion. These return periods, however, varied substantially depending on the channel geometry and the pebble/boulder size distribution of the supplied material. Accordingly, the stream exhibits a highly dynamic boulder cover behaviour. It is likely that these time scales might also have been at work when coarse-grained conglomerates were constructed in the geological past. © 2012 The Authors. Journal compilation © 2012 International Association of Sedimentologists.

Shumilovskikh L.S.,University of Gottingen | Marret F.,University of Liverpool | Fleitmann D.,Institute of Geological science | Fleitmann D.,University of Bern | And 3 more authors.
Marine Micropaleontology | Year: 2013

In order to compare the sea-surface conditions in the Black Sea during the Holocene and Eemian, sapropelic parts of marine core 22-GC3 (42°13.53'N/36°29.55'E, 838. m water depth) were studied for organic-walled dinoflagellate cyst content. The record shows a change from freshwater/brackish assemblages (Pyxidinopsis psilata, Spiniferites cruciformis, and Caspidinium rugosum) to more marine assemblages (Lingulodinium machaerophorum and Spiniferites ramosus complex) during each interglacial, due to the inflow of saline Mediterranean water. The lacustrine-marine transitions in 22-GC3 occurred at ~. 8.3. cal. kyr BP during the early Holocene and ~. 128. kyr BP during the early Eemian, slightly later compared to the onset of interglacial conditions on the adjacent land. Dinoflagellate cyst assemblages reveal higher sea-surface salinity (~. 28-30) (e.g. Spiniferites pachydermus, Bitectatodinium tepikiense, and Spiniferites mirabilis) around ~. 126.5-121. kyr BP in comparison to the Holocene (~. 15-20) as well as relatively high sea-surface temperature (e.g. Tuberculodinium vancampoae, S. pachydermus, and S. mirabilis) especially at ~. 127.6-125.3. kyr BP. Establishment of high sea-surface salinity during the Eemian correlates very well with reconstructed relatively high global sea-level and is explained as a combined effect of increased Mediterranean supply and high temperatures at the beginning of the last interglacial. The observed changes in the dinocyst record highlight the importance of nutrients for the composition of the Eemian and Holocene dinocyst assemblages. © 2013 Elsevier B.V.

Olshtynskaya A.P.,Institute of Geological science | Stefanskaya T.A.,Dnipropetrovsk National University
International Journal on Algae | Year: 2016

Numerous imprints of valves and inner cores of diatoms were revealed by means of a scanning electron microscope on the shells of fossil agglutinating foraminifera Spiroplectammina from the Lower Oligocene deposits of Southern Ukraine. The taxonomic composition of Bacillariophyta, used by foraminifera to build their sceletons, is given. Representatives of at least ten genera were identified including Paralia Heib., Radialiplicata (Z.I. Glezer) Z.I. Glezer, Pseudopodosira A.P. Jousé, Trochosira Kitton, Actinoptychus Ehrenb., and Sceptroneis Ehrenb. We discuss a possible generic composition and ecological preferences of siliceous algae present in the surface layer of bottom sediments of the Maikop basin. © Begell House Inc., 2016.

Angiboust S.,Helmholtz Center Potsdam | Pettke T.,Institute Of Geological science | De Hoog J.C.M.,University of Edinburgh | Caron B.,CNRS Institute of Earth Sciences | Oncken O.,Helmholtz Center Potsdam
Journal of Petrology | Year: 2014

The Monviso ophiolite Lago Superiore Unit (LSU;Western Alps) constitutes a well-preserved, largely coherent fragment of eclogitic upper oceanic lithosphere subducted to c. 80 km depth (between 50 and 40Ma) and exhumed along the subduction interface.Withinslab, 10-100 m thick, eclogite-facies shear zones cut this section; the Intermediate Shear Zone (ISZ) follows the boundary between gabbroic and basaltic eclogites (associated with minor calcschist lenses), and the Lower Shear Zone (LSZ) marks the contact between gabbroic eclogites and the antigorite serpentinite sole. Up to 10 m fragments of mylonitic gabbroic eclogites were transported within serpentinite schists from the LSZ during eclogite-facies deformation. Metasomatic rinds, formed on these fragments during peak to early retrograde lawsonite-eclogite-facies metamorphism (c. 550°C and 2·6 GPa), document episodic, prominent rock-fluid interaction along intra-slab, channelized fluid migration pathways associated with deformation. We present new petrological and geochemical data on hydrous eclogites (talc-, chlorite-, lawsoniteand phengite-bearing eclogites) and serpentinite-derived ultrabasic schists from block rinds. Bulk-rock compositions, laser ablation inductively coupled plasma mass spectrometry mineral analyses and X-ray Cr and Mg maps of garnet and clinopyroxene demonstrate that these samples underwent significant enrichments in Mg, Cr, Ni,large ion lithophile elements and prominent depletions in Fe and V during eclogite-facies metasomatism. Boron isotope data for phengite (δ11B=0 to+7‰; 80

Shumilovskikh L.S.,University of Gottingen | Fleitmann D.,University of Reading | Fleitmann D.,Institute of Geological science | Fleitmann D.,University of Bern | And 5 more authors.
Climate of the Past | Year: 2014

High-resolution pollen and dinoflagellate cyst records from sediment core M72/5-25-GC1 were used to reconstruct vegetation dynamics in northern Anatolia and surface conditions of the Black Sea between 64 and 20 ka BP. During this period, the dominance of Artemisia in the pollen record indicates a steppe landscape and arid climate conditions. However, the concomitant presence of temperate arboreal pollen suggests the existence of glacial refugia in northern Anatolia. Long-term glacial vegetation dynamics reveal two major arid phases ∼64-55 and 40-32 ka BP, and two major humid phases ∼54-45 and 28-20 ka BP, correlating with higher and lower summer insolation, respectively. Dansgaard-Oeschger (D-O) cycles are clearly indicated by the 25-GC1 pollen record. Greenland interstadials are characterized by a marked increase in temperate tree pollen, indicating a spread of forests due to warm/wet conditions in northern Anatolia, whereas Greenland stadials reveal cold and arid conditions as indicated by spread of xerophytic biomes. There is evidence for a phase lag of ∼500 to 1500 yr between initial warming and forest expansion, possibly due to successive changes in atmospheric circulation in the North Atlantic sector. The dominance of Pyxidinopsis psilata and Spiniferites cruciformis in the dinocyst record indicates brackish Black Sea conditions during the entire glacial period. The decrease of marine indicators (marine dinocysts, acritarchs) at ∼54 ka BP and increase of freshwater algae (Pediastrum, Botryococcus) from 32 to 25 ka BP reveals freshening of the Black Sea surface water. This freshening is possibly related to humid phases in the region, to connection between Caspian Sea and Black Sea, to seasonal freshening by floating ice, and/or to closer position of river mouths due to low sea level. In the southern Black Sea, Greenland interstadials are clearly indicated by high dinocyst concentrations and calcium carbonate content, as a result of an increase in primary productivity. Heinrich events show a similar impact on the environment in the northern Anatolia/Black Sea region as Greenland stadials. © Author(s) 2014.

Haertel M.,Institute of Geological science | Herwegh M.,Institute of Geological science
Journal of Structural Geology | Year: 2014

This manuscript deals with the adaptation of quartz-microfabrics to changing physical deformation conditions, and discusses their preservation potential during subsequent retrograde deformation. Using microstructural analysis, a sequence of recrystallization processes in quartz, ranging from Grain-Boundary Migration Recrystallization (GBM) over Subgrain-Rotation Recrystallization (SGR) to Bulging Nucleation (BLG) is detected for the Simplon fault zone (SFZ) from the low strain rim towards the internal high strain part of the large-scale shear zone. Based on: (i) the retrograde cooling path; (ii) estimates of deformation temperatures; and (iii) spatial variation of dynamic recrystallization processes and different microstructural characteristics, continuous strain localization with decreasing temperature is inferred. In contrast to the recrystallization microstructures, crystallographic preferred orientations (CPO) have a longer memory. CPO patterns indicative of prism and rhomb glide systems in mylonitic quartz veins, overprinted at low temperatures (≤400°C), suggest inheritance of a high-temperature deformation. In this way, microstructural, textural and geochemical analyses provide information for several million years of the deformation history. The reasons for such incomplete resetting of the rock texture is that strain localization is caused by change in effective viscosity contrasts related to temporal large- and small-scale temperature changes during the evolution of such a long-lived shear zone. The spatially resolved, quantitative investigation of quartz microfabrics and associated recrystallization processes therefore provide great potential for an improved understanding of the geodynamics of large-scale shear zones. © 2014 Elsevier Ltd.

Schlich K.,Fraunhofer Institute for Molecular Biology and Applied Ecology | Klawonn T.,Fraunhofer Institute for Molecular Biology and Applied Ecology | Terytze K.,Institute of Geological science | Hund-Rinke K.,Fraunhofer Institute for Molecular Biology and Applied Ecology
Environmental Sciences Europe | Year: 2013

Background: Silver nanoparticles (AgNPs) are widely used in many fields of application and consumer products due to their antibacterial properties. The aim of this study was to prepare a hazard assessment for one specific AgNP in soil, incorporated via sewage sludge (the sewage sludge pathway). The effects of pristine AgNPs on microorganisms, plants and earthworms were first determined in screening tests. Long-term tests over 140 days were then conducted with AgNPs added to soil via sewage sludge. AgNPs were incorporated into the sludge through a simulated sewage treatment plant (STP) over 10 days to allow transformation to occur and also by manual spiking over 2 h. The results of the most sensitive organism from the long-term tests, the soil microorganisms, are presented. Results: The STP simulations confirmed that at environmentally relevant concentrations >90% of AgNPs remain bound to sewage sludge. Effects of AgNPs bound to sewage sludge and added to soil were similar to that of pristine NM-300K after degradation of the sludge. The predicted no-effect concentration for NM-300K in soil of 0.05 mg/kg dry soil determined a maximum threshold of 30 mg/kg dry sludge per application, considering the maximum addition of sewage sludge in Germany (5 tons per hectare every 3 years). Conclusion: At environmentally relevant concentrations, AgNP absorption to sludge and aging in soil (even after transformation) cause toxic effects on soil microorganisms of the terrestrial ecosystem. © 2013 Schlich et al.; licensee Springer.

Schlich K.,Fraunhofer Institute for Molecular Biology and Applied Ecology | Schlich K.,Institute of Geological science | Klawonn T.,Fraunhofer Institute for Molecular Biology and Applied Ecology | Terytze K.,Institute of Geological science | Hund-Rinke K.,Fraunhofer Institute for Molecular Biology and Applied Ecology
Environmental Toxicology and Chemistry | Year: 2013

The widespread use of silver nanoparticles (Ag-NPs), for example, in textiles and cleaning products, means that they are likely to reach the environment via biosolids or the effluent from wastewater treatment plants. The aim of the present study was to determine the ecotoxicity of Ag-NPs in the earthworm reproduction test using Eisenia andrei. In addition to the usual endpoints, the authors also investigated the uptake and accumulation of Ag by adult earthworms and the concentration of free Ag+ in soil pore water. Silver nanoparticles and Ag nitrate showed similar toxicities in the earthworm reproduction test. The uptake of Ag from Ag-NPs in the earthworm was slightly higher than the uptake of Ag from Ag nitrate. Spiked soils showed a concentration-dependent effect on reproduction, but there was no concentration-dependent increase in the amount of Ag in earthworm tissues. The authors noted a concentration-dependent increase in the levels of free Ag+ in the soil pore water regardless of the Ag source. The number of juveniles is a more suitable endpoint than biomass or mortality. The uptake of Ag does not appear to inhibit reproduction. Instead, inhibition seems to reflect Ag+ released into the soil pore water, which affects cocoons and juveniles in the soil. Analysis of transformed Ag-NPs after purification in wastewater treatment plants would provide additional information. © 2012 SETAC.

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