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  • Other Sources  (35)
  • Bornträger  (17)
  • Inst. f. Geophys., Ruhr-Univ. Bochum  (12)
  • Elsevier  (6)
  • 2010-2014
  • 1980-1984  (35)
  • 1982  (17)
  • 1981  (18)
  • 1
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    Elsevier
    In:  Bull., Polar Proj. OP-O3A4, Computer-aided Seismic Analysis and Discrimination, London, Elsevier, vol. 16, no. 4, pp. 97-109, (ISBN 0080419208)
    Publication Date: 1981
    Keywords: Group veloc. ; Velocity analysis
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  • 2
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Wissenschaftl. Veröffentl. (Reihe B), Hrsg. H.-P. Harjes, Atlanta, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 10, no. PL-TR-91-2127, pp. 1219-1222
    Publication Date: 1981
    Keywords: BUG ; ERDSTOSS (see also rockburst and Gebirgsschlag) ; Mining geophysics ; GEBIRGSSCHLAG (see also rockburst and Erdstoss) ; Earthquake catalog ; Rock bursts (see also ERDSTOSS and GEBIRGSSCHLAG) ; Local earthquakes
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  • 3
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Dissertation, Berichte, Bochum, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 10, no. 9, pp. 1109-1111
    Publication Date: 1981
    Keywords: Geomagnetics ; Plate tectonics ; Borehole geophys.
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  • 4
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Wissenschaftl. Veröffentl. (Reihe B), Hrsg. H.-P. Harjes, Atlanta, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 10, no. PL-TR-91-2127, pp. 1219-1222
    Publication Date: 1982
    Keywords: BUG ; ERDSTOSS (see also rockburst and Gebirgsschlag) ; Mining geophysics ; GEBIRGSSCHLAG (see also rockburst and Erdstoss) ; Earthquake catalog ; Rock bursts (see also ERDSTOSS and GEBIRGSSCHLAG) ; Local earthquakes
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  • 5
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Diplomarbeit, La Jolla, CA, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 1034, no. 77-767, pp. 293-297, (ISBN 3-933346-037)
    Publication Date: 1982
    Keywords: Seismology ; Seismic arrays
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  • 6
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Diplomarbeit, Menlo Park, California, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 1034, no. 77-3, pp. 262-277, (ISBN 3-933346-037)
    Publication Date: 1982
    Keywords: Mining geophysics ; Channel waves ; Layers ; Layers ; Love-waves ; Dispersion ; Rader
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  • 7
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Diplomarbeit, Univ. Karlsruhe, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 1034, no. 85-739, pp. 1-109, (ISBN 3-933346-037)
    Publication Date: 1982
    Keywords: Seismic stratigraphy
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  • 8
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Diplomarbeit, Rome, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 10, no. 13, pp. 1431-1434, (ISBN 0 08 042822 3)
    Publication Date: 1981
    Keywords: Velocity ; Physical properties of rocks ; Laboratory measurements ; Instruments ; Wohrl
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  • 9
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Wissenschaftl. Veröffentl. (Reihe A), Los Angeles, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 10, no. 41, pp. 143, (ISBN 3-933346-037)
    Publication Date: 1982
    Keywords: Data analysis / ~ processing ; Discrimination ; PIC ; gab ; Seismology ; Surface waves ; Data analysis / ~ processing ; Broad-band ; Detectors ; Nuclear explosion
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  • 10
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Diplomarbeit, Tokyo, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. C 560, 183 pp., no. 29, pp. 1321-1323, (ISBN 3-933346-037)
    Publication Date: 1981
    Keywords: SEModelling ; Channel waves ; Mining geophysics ; Rayleigh waves ; Kuhbach
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  • 11
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Diplomarbeit, Hannover, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 10, no. Publ. num. 191, pp. 1-32, (ISBN 3-933346-037)
    Publication Date: 1982
    Keywords: Seismology ; Dispersion ; Rayleigh waves
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  • 12
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Technical Report, Hanscom Air Force Base, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. C 560, 183 pp., no. PL-TR-91-2250, pp. 1-25, (ISBN 3-933346-037)
    Publication Date: 1982
    Keywords: Seismics (controlled source seismology) ; SEModelling ; Mining geophysics ; Channel waves
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  • 13
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Dissertation, Berichte, Houston, Inst. f. Geophys., Ruhr-Univ. Bochum, no. 10, pp. 103-155
    Publication Date: 1981
    Keywords: Stress ; cracks and fractures (.NE. fracturing) ; Fracture ; Laboratory measurements
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  • 14
    Publication Date: 2016-04-08
    Description: Acoustic basement lies at an average of between 6.0 and 6.5 sec two-way time below sea level in the southern Rockall Trough and northern Porcupine Abyssal Plain. The overlying sedimentary succession reaches maximum thicknesses of at least 4.0 sec, and can be divided by 3 regionally-developed seismic reflecting horizons, which are used as a framework to establish an acoustic stratigraphy for the area by selecting three “type” seismic sections. These reflectors are named, in ascending order, Shackleton, Charcot and Challenger. The area is crossed by E—W basement high structures, the Clare Lineament (which may be an easterly extension of the Charlie Gibbs Fracture Zone), that separates the Porcupine Abyssal Plain from the eastern part of southern Rockall Trough. Under the latter, the post-Shackleton acoustic sequence is thickened, as if dammed to the north of the Clare Lineament, whilst a further thickening, above reflector Charcot, occurs along a NE—SW line somewhat farther north into the southern Rockall Trough. This can also be related to shallow-lying acoustic basement features. Pre-Shackleton sediments overlie a very irregular basement topography. The acoustic characters of the various sediment packages are described and it is speculated that major changes in the sedimentary environments took place across reflectors Shackleton and Challenger, the latter probably establishing the modern bottom current circulation patterns. No ages can be unequivocally assigned to the main reflectors, but previously published data suggest a late Eocene—Oligocene age for Challenger. Possible lavas or sills are identified in the succession between reflectors Shackleton and Charcot.
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  • 15
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    Elsevier
    In:  Tectonophysics, 73 (1-3). pp. 151-168.
    Publication Date: 2021-06-08
    Description: The structural setting of the Maltese Islands is governed by two rift systems of different ages and trends and the interference of both. Accompanying faults are exposed at many places along cliffs and belong to the most spectacular phenomena of rift faulting of the world. Malta is part of a wide shelf bridge that connects the Ragusa platform of southern Sicily and the Tripolitanian platform of northern Libya. The archipelago is underlain by a continental crust of African provenance. The older rift generation traversing the islands strikes about 50° to 70° to create a basin-and-range structure on western Malta, Comino and eastern Gozo. This micro-province is framed by two master faults at an average distance of 14 km. Crustal extension started during the Early Miocene, as observed by growth faulting and sedimentary dikes parallel to the future rift. A syndepositional uparching of about 200 m has preceded the physiographical rifting in post-Middle Miocene times. Discrete dip-slip faulting created an external wedge block, split by internal tilt blocks of antithetic character, both compensating an average 15% crustal spreading normal to the rift axis. Shoulder upwarping of approximately 120 m has evolved synchronously with the rifting. Structures of the first generation are crosscut by still active, second-generation rift faults, which on Malta strike about 120°, but on Gozo between 80° and 90°. These faults are associated with the Pantelleria rift, whose deep trough sets immediately south of the islands. Rifting was mainly originated during Late Miocene/Early Pliocene time to continue in parts up to the Present. A set of transform faults runs through the straits on both sides of Comino to form a complicated en echelon or Riedel shear structure on easternmost Gozo and westernmost Malta. Shoulder upwarping related to the Pantelleria rift has considerably tilted the block of Malta NNE-ward and caused the inundated river valleys of the natural harbour of Valletta. The superimposition of two rift structures of different trends has been caused principally by a rotation of the controlling stress regime about 10 m.y. ago. The active Afro—Eurasian collision front is located about 200 km north and northwest of the islands. A contemporary change of plate tectonic stresses is discussed to explain the intraplate rift pattern on Malta as foreland-specific reactions to plate tectonic processes.
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  • 16
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    Elsevier
    In:  Zentralblatt für Bakteriologie Mikrobiologie und Hygiene: I. Abt. Originale C: Allgemeine, angewandte und ökologische Mikrobiologie, 3 (3). pp. 358-363.
    Publication Date: 2021-04-26
    Description: Menaquinones (vitamin K2) were the only isoprenoid quinones found in the Actinomycetes tested. Thermomonospora strains belonging to the species T. alba, T. curvata and T. fusca contained very complex mixtures of menaquinones with nine, ten and eleven isoprene units. Hexa- and octahydrogenated menaquinones with ten isoprene units constituted the major components in T. alba, whereas, octahydrogenated menaquinones with ten isoprene units predominated in T. curvata and T. fusca. Substantial amounts of hitherto undescribed hexa-, octa-, and decahydrogenated menaquinones with eleven isoprene units were also present in the three species. The representative of the taxon Thermomonospora (Actinobifida) chromogena examined differed in possessing major amounts of tetrahydrogenated menaquinones with only nine isoprene units; a pattern also found in Saccharomonospora viridis, Actinomadura flexuosa and Micromonospora halophytica subsp. halophytica. The chemotaxonomic data and supporting results of numerical taxonomic studies suggest that Actinobifida chromogena may have been wrongly classified in the genus Thermomonospora.
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  • 17
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    Elsevier
    In:  Geochimica et Cosmochimica Acta, 45 (4). pp. 577-588.
    Publication Date: 2016-03-01
    Description: Generally, oxidative regeneration of phosphate from anoxic sediments is by microbially mediated sulfate reduction processes. Stoichiometric modelling of such reactions takes into consideration varying proportions of ‘decomposable’ organically bound P to account for the ratios among nutrients in depth-concentration profiles of near-surface sediments. New results of interstitial water composition from sediments underlying the water masses influenced by coastal upwelling of the eastern boundary current system off Peru indicate that dissolution of phosphatic fish debris represents a mechanism for remineralization of phosphate comparable to or larger in magnitude than that by oxidative regeneration of organically bound P. Dissolved interstitial phosphate from fish debris is revealed by an excess amount of phosphate over that predicted from a simple stoichiometric oxidative regeneration model and by anomalously high dissolved interstitial fluoride concentrations. Phosphate flux estimates based on diffusion from the sediment suggest that this mechanism may generate up to 10% of the nutrient pool in the waters of the Peru undercurrent. Partitioning of P among the two sources reveals further that fish debris phosphate is about four times more important than organically bound P in nutrient generation from sediments of the Peru continental margin. Not only does this mechanism of regeneration affect the nutrient cycling but may also control widespread phosphorite formation in this area.
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  • 18
    Publication Date: 2018-07-25
    Description: Investigations of formation-fluid salinities in a transect from western Georgia to the edge of the Blake Plateau off the coast of Georgia show surprisingly similar hydrochemical features offshore and onshore. A fresh-brackish wedge of groundwater (〈25 g/kg total dissolved solids) lies beneath the shelf to a depth of ∼ 900 m. On land, brackish waters extend to a maximum depth of ∼ 1.2 km below sea level in Lowndes County, Georgia. In deeper horizons, hypersaline brines (〉 100 g/kg) occur in Lower Cretaceous (?) strata. These strata have a pronounced evaporitic (anhydritic) character in the offshore segment. Strong salinity gradients in interstitial waters signify buried evaporite deposits at drill sites beneath the Blake Plateau.
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  • 19
    Publication Date: 2022-06-27
    Description: Tracking a balloon with a single ship-based theodolite, is a method which has been used for a long time to determine the wind profile over the sea. There are two main sources of error: (a) the incorrect estimate of the height of the balloon and (b) the pitch and roll motions of the ship. In this paper the effects of both errors are investigated. The ship's motion is simulated with use of a transformation from a fixed (earth) to a moving (ship) coordinate system. Some examples are presented to illustrate the magnitude of these effects.
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  • 20
    Publication Date: 2022-06-27
    Description: During the 1971 "Meteor" survey of the Mediterranean Outflow, seven current meter moorings were deployed and several hydrographic stations executed. The time series data from almost all the current meters revealed a solitary increase in temperature with an amplitude of ≃ 1 °C and a duration of 2-4 days. The present analysis of the event shows that it was due to a thickening of the Mediterranean Outflow and an increase in the volume transport. The origin of the event is traced to the source of the Outflow from where it propagated with a speed of 16 cm s-1. Coinciding with the time at which the event passed the Strait of Gibraltar, the cross channel water level difference revealed an anomalous variation of about 8-cm amplitude and 3-day duration. Through conversion the magnitude of this fluctuation is now shown to simply a significant increase in the Outflow volume transport. An investigation of the reigning meteorological conditions indicates that, simultaneously, an impulse of water in the Alboran Sea was transported westwards by the wind. Through a qualitative and quantitative approach, the atmospheric forcing of the Western Mediterranean is thus linked to a large variation in the Outflow structure.
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  • 21
    Publication Date: 2022-06-27
    Description: On a cruise from the eastern into the western Mediterranean Sea in November/December 1978 a total of 126 samples were collected from 8 vertical profiles and 7 coastal stations for trace metal analysis. The sampling, processing and analysis was performed under strict "clean room" conditions. The concentration of the open-sea samples are close to oceanic results gathered under similar conditions. The grand averages from all profiles ( ± st. dev. of the individual samples) of 0.40 ± 0.16 µg l-1 Zn, 17.4 ± 7.4 ng l-1 Cd, 0.21 ± 0.07 µg l-1 Cu, 0.21 ± 0.13 µg l-1 Mn and 0.25 ± 0.09 μg l-1 Fe indicate that a "metal problem" does not exist in the open Mediterranean. A biologically mediated depletion in surface waters or correlation with nutrients have not been observed under the conditions established on this cruise. This is probably due to low primary production and seasonal advection processes prevailing in this sea. The data for manganese show generally higher values in the surface layer (0-75 m) than in deep waters. This could evidently proved in the nearshore profile indicating a terrigenous source for manganese.
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  • 22
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    Bornträger
    Publication Date: 2022-06-27
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  • 23
    Publication Date: 2022-06-28
    Description: In general the natural aerosol reacts very sensitively to the change of relative humidity. This behaviour could be observed from August to September during the Atlantic "Meteor" -Expedition 1965, but not during the periods January to May 1969 and July to August 1974. There are some reasons for the assumption that this is an effect of organic material in the surfaces of the particles. But we do not know if this is an effect of different seasons or of increasing pollution of the atmospheric aerosol.
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  • 24
    Publication Date: 2022-07-26
    Description: Five reflection seismic profiles from the borderland between Messina Abyssal Plain and Malta Ridge (= Medina Rise), recorded during "Meteor" cruise no. 50 in 1978, are described. The subbottom/bottom structures are interpreted as a pattern of broad grabens and intercalated SW-NE striking narrow horsts. Within the grabens great thicknesses of Messinian evaporites as well as of Quaternary turbiditic sediments, depending on the respective differential sinking, were accumulated. Some of the horsts rise above the surrounding seafloor. Ontop of the horsts, being mainly composed of pre-Messinian series, only little or no evaporites at all were deposited. The cover of Quaternary sediments depends on the position of the horst with respect to the seafloor. The thickness of Pliocene sediments is constant within the whole studied area. The authors conclude from the observations that the pattern of horsts and grabens acted already during Messinian time producing the variable thickness of the evaporite layer. The relative movements between grabens and horsts as well as a general sinking of the whole area must have acted also in Pliocene and Quaternary time.
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  • 25
    Publication Date: 2022-07-26
    Description: Three sediment cores from the continental shelf and slope off NW Africa (Banc d'Arguin; 52 m, 665 m, and 973 m water depth) have been investigated by means of a coarse fraction analysis. The two shallower cores have been deposited during less than 10,000 years, the deeper one during the last 36,000 years. The Holocene sedimentation (〈 4000 years) in the deeper part of core 79 from the edge of the Banc d'Arguin is strongly influenced by reworking of Late Glacial dune sands and biogenic particles from shallower water (〈 40 m), as well as eroding current influence. A decrease in grain size of silicate material and a decrease in lateral supply, correlated to a doubling of accumulation rates in the upper part of the core, indicates a more autochthonous sedimentation with less sorting influence in the youngest Holocene. In core 86 from 665 m water depth a turbidite consisting mainly of silicate sand and silt separates two layers of autochthonous Holocene sediments. This turbidite shows a complete bioturbational mixing, only at its bottom the original bedding can be detected. Gradational changes in sediment composition indicate the decreasing admixture of allochthonous material from the bottom of the turbidite in 300 cm to about 140 (100) cm core depth. The depth of provenance of the allochthonous material can be assumed in 100-300 m water depth as indicated by various biogenous particles. Small amounts of shallow water particles in the autochthonous layers indicate a supply from shallow water, which probably occurred by the mechanism of "particle by particle supply". None of the three cores indicates upwelling influence, although oceanographers found intense upwelling in the area of the Banc d'Arguin. The Holocene climate in that area probably has been arid, small variations in terrigenous matter composition and grain size in the Early Holocene might be due to decreased wind strength or to an increase in rain fall. The Peak Glacial section (14,000-22,000 y.B.P.) of the deepest core 88 indicates a very much intensified eolian silt supply and an additional bottom supply of quartz sand. In the interval 22,000-36,000 y.B.P. wind strength decreased, but probably no increase in humidity occurred. So this area in about 19° 40' N had an arid climate in the Late Holocene and in the Peak Glacial. The fragmentation of planktonic foraminifers and the abundance of aragonitic tests of pteropods in core 88 indicate an Early Holocene (8330 y.B.P.) preservation spike. Two minima in fragmentation correlated to maxima in pteropod content at about 15,700 and 21,000 y.B.P. are correlated to maxima in shallow water supply and thus do not reflect preservation conditions, but only lateral supply from the carbonate dissolution minimum zone in about 300 m water depth.
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  • 26
    Publication Date: 2022-07-26
    Description: 86 sediment cores retrieved from water depths greater than 500 m off NW Africa between 12° and 28° N, were investigated by means of X-ray radiographs. Biogenic sedimentary structures occupy more than 90% of the examined area of sediment sections with the remaining 2% being turbidites and 8% slump masses. More than 20 types of lebensspuren can be distinguished. Most of them correspond to ichnogenera known from the fossil record: Chondrites, Corophioides, Helminthopsis, Lophoctenium, Planolites, Scolicia, Skolithos) Teichichnus) Thalassinoides) Trichichnus and Zoophycos. The observations are "uniformitarian" with respect to the lebensspuren encountered. Nevertheless, fossil counterparts to our sediments are not known, because (i) similar sedimentation processes at present are restricted to small areas, (ii) all of them are situated on passive continental margins, which are rarely preserved in the fossil record, and (iii) biogenic structures in silty marlstones are normally not very conspicuous in the fossil state. The sediments are highly bioturbated; in most cases biogenic reworking occurs repeatedly. The behaviour of the infaunal organisms and thus the formation of lebensspuren depends from the nutrient supply: In sediments with Corg greater than 2% only biodeformational structures are observed, while with Corg lower than 2% lebensspuren predominate. The lebensspuren inventory was found to be systematically arranged in a number of "bioturbation levels" below the sediment surface. With increasing sediment depth, a higher specialisation in the behaviour of the fauna is observed. Moreover, in each group of lebensspuren, the diameter decreases. The following levels are established: i. Level with biologically homogenized sediment, ii. Scolicia level (tubes, 2-4 cm diameter), iii. Planolites level tubes, 1 cm diameter), iv. level with small burrows of Chondrites) Helminthopsis (tube systems, 1-3 mm diameter) and spreiten burrows of Corophioides) Lophoctenium) and Teichichnus, v. Zoophycos level (spreiten burrows). With increasing water depth, the thickness of the bioturbated sediment decreases from 80 cm at 500 m to 40-60 cm at 2000 m and 15-25 cm at 4750 m. Based on the levels, biogenic sedimentary structures are grouped into "associations" having ecological significance. The following associations are established: (1) biodeformational association dominating in sediments with Corg greater than 2% ; (2) Scolicia association, (3) Planolites association [(2) and (3) depend on the sediment grain size: (2) in sediments with high content of silicate particles 〉 20 μm, (3) in sediments with clay content 〉 50%] ; ( 4) Vertical spreiten association, (5) Chondrites association, (6) Zoophycos association [( 4) through ( 6) predominate in glacial sediments, (4) in water depth about 1000 m, (5) below 1000 m, and (6) between 2000 and 4000 m]. The formation of different biogenic sedimentary structures and thus the distribution of lebensspuren associations depends on the environmental conditions. Generally, the diversity of lebensspuren is higher in glacial than interglacial sediments. This phenomenon is attributed to a higher rate of Corg accumulation and preservation in glacial sediments, possibly because of changes in the circulation of water masses. The sediments become mixed in different style by different lebensspuren types. Because biogenic reworking is - as a rule - repeated several times, the vertical mixing effect is considerable, though difficult to estimate. Stratigraphic resolution is optimal in core sections with Scolicia, where vertical mixing is restricted. Here stratigraphic resolution reaches an accuracy of about 200-300 years where the sedimentation rate is 10-20 cm/1000 years.
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  • 27
    Publication Date: 2022-07-26
    Description: The terrigenous sediment proportion of the deep-sea sediments from off Northwest Africa has been studied in order to distinguish between the aeolian and the fluvial sediment supply. The present and fossil Saharan dust trajectories were recognized from the distribution patterns of the aeolian sediment. The following time slices have been investigated: Present, 6,000, 12,000 and 18,000 y.B.P. Futhermore, the quantity of dust deposited off the Saharan coast has been estimated. For this purpose, 80 surface sediment samples and 34 sediment cores have been analysed. The stratigraphy of the cores has been achieved from oxygen isotopic curves, 14 C-dating, foraminiferal transfer temperatures, and carbonate contents. Silt sized biogenic opal generally accounts for less than 2% of the total insoluble sediment proportion. Only under productive upwelling waters and off river mouths, the opal proportion exceeds 2% significantly. The modern terrigenous sediment from off the Saharan coast is generally characterized by intensely stained quartz grains. They indicate an origin from southern Saharan and Sahelian laterites, and a zonal aeolian transport in midtropospheric levels, between 1.5 and 5.5 km, by "Harmattan" Winds. The dust particles follow large outbreaks of Saharan air across the African coast between 15° and 21° N. Their trajectories are centered at about 18° N and continue further into a clockwise gyre situated south of the Canary Islands. This course is indicated by a sickle-shaped tongue of coarser grain sizes in the deep-sea sediment. Such loess-sized terrigenous particles only settle within a zone extending to 700 km offshore. Fine silt and clay sized particles, with grain sizes smaller than 10-15 μm, drift still further west and can be traced up to more than 4,000 km distance from their source areas. Additional terrigenous silt which is poor in stained quartz occurs within a narrow zone off the western Sahara between 20° and 27° N only. It depicts the present dust supply by the trade winds close to the surface. The dust load originates from the northwestern Sahara, the Atlas Mountains and coastal areas, which contain a particularly low amount of stained quartz. The distribution pattern of these pale quartz sediments reveals a SSW-dispersal of dust being consistent with the present trade wind direction from the NNE. In comparison to the sediments from off the Sahara and the deeper subtropical Atlantic, the sediments off river mouths, in particular off the Senegal river, are characterized by an additional input of fine grained terrigenous particles (〈 6 μm). This is due to fluvial suspension load. The fluvial discharge leads to a relative excess of fine grained particles and is observed in a correlation diagram of the modal grain sizes of terrigenous silt with the proportion of fine fraction (〈 6 μm). The aeolian sediment contribution by the Harmattan Winds strongly decreased during the Climatic Optimum at 6,000 y.B.P. The dust discharge of the trade winds is hardly detectable in the deep-sea sediments. This probably indicates a weakened atmospheric circulation. In contrast, the fluvial sediment supply reached a maximum, and can be traced to beyond Cape Blanc. Thus, the Saharan climate was more humid at 6,000 y.B.P. A latitudinal shift of the Harmattan driven dust outbreaks cannot be observed. Also during the Glacial, 18,000 y.B.P., Harmattan dust transport crossed the African coast at latitudes of 15°-20° N. Its sediment load increased intensively, and markedly coarser grains spread further into the Atlantic Ocean. An expanded zone of pale-quartz sediments indicates an enhanced dust supply by the trade winds blowing from the NE. No synglacial fluvial sediment contribution can be recognized between 12° and 30° N. This indicates a dry glacial climate and a strengthened atmospheric circulation over the Sahelian and Saharan region. The climatic transition phase, at 12,000 y.B.P., between the last Glacial and the Interglacial, which is comparable to the Allernd in Europe, is characterized by an intermediate supply of terrigenous particles. The Harmattan dust transport was weaker than during the Glacial. The northeasterly trade winds were still intensive. River supply reached a first postglacial maximum seaward of the Senegal river mouth. This indicates increasing humidity over the southern Sahara and a weaker atmospheric circulation as compared to the Glacial. The accumulation rates of the terrigenous silt proportion (〉 6 μm) decrease exponentially with increasing distance from the Saharan coast. Those of the terrigenous fine fraction (〈 6 μm) follow the same trend and show almost similar gradients. Accordingly, also the terrigenous fine fraction is believed to result predominantly from aeolian transport. In the Atlantic deep-sea sediments, the annual terrigenous sediment accumulation has fluctuated, from about 60 million tons p.a. during the Late Glacial (13,500-18,000 y.B.P., aeolian supply only) to about 33 million tons p.a. during the Holocene Climatic Optimum (6,000-9,000 y.B.P., mainly fluvial supply), when the river supply has reached a maximum, and to about 45 million tons p.a. during the last 4,000 years B.P. (fluvial supply only south of 18° N).
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  • 28
    Publication Date: 2022-07-27
    Description: Psephitic particles in the region of the Iceland-Faeroe-Ridge have been transported and deposited by means of a complex interplay of glacier movements and drifting icebergs. The composition of the particle association is controlled by the sedimentation of basaltic rock particles derived from the ridge itself and, in addition to that and in southern parts of the ridge, from the Faeroe Islands, the Faeroe-Bank and the Bill Baileys-Bank. Besides, there are crystalline and sedimentary dropstones showing a very varied petrography and a wide range of particle sizes. Their percentage becomes greater as the distance from the ridge increases. The association of dropstones is relatively homogeneous in the region of the ridge and only at greater distances from the ridge it becomes more differentiated. Owing to their composition and distribution, as well as on the basis of characteristic fossils and rock types, the dropstones are derived from Scandinavia and Great Britain. During periods of maximum glaciation, the Iceland-Faeroe-Ridge, the Faeroe-Bank and the Bill Baileys-Bank were under ice.
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  • 29
    Publication Date: 2022-07-27
    Description: The aragonite compensation depth was described by pteropods in surface sediments at the northeastern Atlantic continental margin between 12° and 48° N. It rises from 3100 m up to 400 m water depth in the high-productivity zones of fertile upwelling and river discharge.
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  • 30
    Publication Date: 2022-07-27
    Description: Seven sediment cores from the cruises of the "Meteor" and "Valdivia" were examined palynologically. The cores were retrieved from the lower continental slope in the area of between 33.5° N and 8° N, off the West African coast. Most of the cores contain sediments from the last Glacial and Interglacial period. In some cases, the Holocene sediments are missing. Some individual cores contain sediments also from earlier Glacial and Interglacial periods. The main reason for making this palynological study was to find out the differences between the vegetation of Glacial and Interglacial periods in those parts of West Africa which at present belong to the Mediterranean zone, the Sahara and the zones of the savannas and tropical forests. In today's Mediterranean vegetation zone at core 33.5° N, forests and deciduous forests in particular, are missing during Glacial conditions. Semi-deserts are found instead of these. In the early isotope stage 1, there is a very significant development of forests which contain evergreen oaks; this is the Mediterranean type of vegetation development. The Sahara type of vegetation development is shown in four cores from between 27° N and 19° N. The differences between Glacial and Interglacial periods are very small. It must be assumed therefore that in these latitudes, both Glacial and Interglacial conditions gave rise to deserts generally. The results are in favour of a slightly more arid climate during Glacial and a more humid one during Interglacial periods. The southern boundary of the Sahara and the adjacent savannas with grassland and tropical woods were situated more to the south during the Glacial periods than they were during the Interglacial ones. In front of today's savanna belt, it can be seen from the palynological results that there are considerable differences between the vegetation of Glacial and Interglacial periods. The woods are more important in Interglacial periods. During the Glacial periods these are replaced from north to south decreasingly by grassland (savanna and rainforest type of vegetation development). The southern limit of the Sahara during stage 2 was somewhere between 12° N and 8° N which is between 1.5 and 5 degrees in latitude further south than it is today. Not only do these differences in climate and vegetation apply to the maximum of the last Glacial and for the Holocene, but they apparently apply also to the older Glacial and Interglacial periods, where they have been found in the profiles. The North African desert belt can be said to have expanded during Glacial times both towards the north and towards the south. All the available evidence of this study indicates that the grassland or the semi-deserts of Southern Europe came into connection with those of N Africa; there could not have been any forest zone between them. The present study was also a good opportunity for investigating some of the basic marine palynological problems. The very well known overrepresentation of pollen grains of the genus Pinus in marine sediments can be traced as far as 21° N. The present southern limit for the genus Pinus is on the Canaries and on the African continent at approximately 31° N. Highest values of Ephedra pollen grains even occur south of the main area of the present distribution of that genus. There does not seem to be any satisfactory explanation for this. In general, it would appear that the transport of pollen grains from the north is more important than transport from the south. The results so far, indicate strongly that further palynological studies are necessary. These should concentrate particularly on cores from between 33° N and 27° N as well as between 17° N and 10° N. It would also be useful to have a more detailed examination of sediments from the last Interglacial period (substage 5 e). Absolute pollen counts and a more general examination of surface samples would be desirable. Surface samples should be taken from the shelf down to the bottom of the continental slope in different latitudes.
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  • 31
    Publication Date: 2022-08-29
    Description: 33 species of polychaetes were collected, 27 of them were determined to species level. The majority of the species are cosmopolitans. Pulliella armata FAUVEL was found the first time in the Atlantic Ocean off Northwest Africa.
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  • 32
    Publication Date: 2022-08-29
    Description: The new Harpacticoidea genus Thieliella nov. gen. of the family Ancorabolidae SARS sensu LANG, 1909 with two new species from 500 m depth of the Island-Faroer-Ridge is described and discussed: Thieliella nordatlantica nov. spec. and Th. reducta nov. spec.
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  • 33
    Publication Date: 2022-08-29
    Description: 80 species of polychaetes were collected, 76 of them were determined to species level. One species (Harmothoe [Austrolaenilla] meteorae n. sp.) was described as new species. The majority of the species including the species of the cruises 26 and 44 are cosmopolitans (18%); 16% are distributed in cool temperate to tropical zones, 12.5% have their distribution in the eastern Atlantic and the Mediterranean, and 11% are distributed in tropical-subtropical to warm temperate zones.
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  • 34
    Publication Date: 2022-08-29
    Description: Nine species of Flustridae were collected by the R.V. "Meteor" in one subantarctic and three antarctic stations. Two new genera (Austroflustra and Neoflustra) and three new species (Austroflustra gerlachi, A. australis and Neoflustra dimorphica) are described. The diagnosis of the family is emended to include species with adventitious avicularia. Nematoflustra bifoliata D'HONDT and Flustra thysanica MOYANO are placed in the genus Securiflustra SILEN, and Flustra vulgaris KLUGE is transfered to Austroflustra.
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  • 35
    Publication Date: 2022-08-29
    Description: The species Stenhelia (Delavalia) noodti n. sp., Stenhelia (Delavalia) islandica n. sp., Pseudomesochra scheibeli n. sp. and Ameira faroerensis n. sp. are described from 500 m depth on the Island-Faroer-Ridge. Of special interest is Stenhelia (Delavalia) noodti n. sp. showing a reduction of the Exp A2 to one segment, a character described for this genus for the first time.
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