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1

Digitale Medien

Mud volcano gas hydrates in the Gulf of Cadiz (2002)

Mazurenko, L. L. ; Soloviev, V. A. ; Belenkaya, I. ; [weitere]

Oxford, UK : Blackwell Science Ltd

Terra nova 14 (2002), S. 0

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ISSN: 1365-3121

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Geologie und Paläontologie

Notizen: This paper presents new geochemical data on gas-hydrate-bearing mud volcanoes discovered for the first time in the Gulf of Cadiz during cruises TTR9 and TTR10 of the R/V Professor Logachev in 1999–2000. The estimated gas hydrate content is 3–16% of sediment volume and 5–31% of pore space volume. Estimated values of the water isotopic composition for the Ginsburg mud volcano are very heavy for δ18O (up to +53‰) and light for δD (up to − 210‰). Gas released from the hydrates contains 81% of C1 and 19% of C2+. The inferred source of the gas in the hydrates is enriched in C2–C6 (≤ 5%), indicating that the gas has a thermogenic origin. Gas hydrate of cubic structure II should be formed from a gas of such composition. It is interpreted that the composition of the mud volcano fluid corresponds to deep oil basins below the Gulf of Cadiz.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1046/j.1365-3121.2002.00428.x

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2

Digitale Medien

The seismic velocity structure of some NE Atlantic continental rise sediments; a lithification index? (1990)

Whitmarsh, R. B. ; Miles, P. R. ; Pinheiro, L. M.

Oxford, UK : Blackwell Publishing Ltd

Geophysical journal international 101 (1990), S. 0

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ISSN: 1365-246X

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Geologie und Paläontologie

Notizen: Two separate sets of experiments with digital ocean-bottom seismographs (DOBS) and airguns, on continental rise areas off Madeira and west of Portugal, produced en echelon second arrivals from the sediment layer on record sections. Traveltime and synthetic seismograrn modelling indicate that the arrivals represent multiply-reflected refracted phases which have undergone reflection within the sediment layer itself. Further, although the P-wave contrast at the intrasediment reflecting horizon is relatively small, the modelling indicates a large downward increase in S-wave velocity from 100–250 m s−1 (Poisson's ratio of at least 0.42) to about 1200 m s−1 (Poisson's ratio of about 0.25). A reflection event can usually be found on reflection profiles along the refraction lines at almost exactly the same ‘depth’ as the intrasediment reflector. In one case such an event can be traced to a nearby Deep Sea Drilling Project (DSDP) borehole where it is associated with the transition from ooze to chalk. This, and other circumstantial evidence, suggests that the intrasediment reflector marks an important increase in lithification within the sediment layer. If so it means that, in future, straightforward OBS experiments may be used to measure the depth of this increase without resorting to the drill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1365-246X.1990.tb06575.x

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3

Digitale Medien

The ocean–continent boundary off the western continental margin of Iberia—II. Crustal structure in the Tagus Abyssal Plain (1992)

Pinheiro, L. M. ; Whitmarsh, R. B. ; Miles, P. R.

Oxford, UK : Blackwell Publishing Ltd

Geophysical journal international 109 (1992), S. 0

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ISSN: 1365-246X

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Geologie und Paläontologie

Notizen: An 80 km long reversed seismic refraction line (Line 5) was shot over the Tagus Abyssal Plain off Portugal. The main P-wave reflected and refracted phases were modelled both for traveltime and amplitude. The resulting P-wave velocity/depth model has the following features: (a) an extremely thin crust of about 2 km; (b) the absence of oceanic layer 3; and (c) very low upper mantle velocities between 7.6 and 7.9 km s-1. This very unusual seismic velocity crustal structure is quite unlike thinned continental crust but is remarkably similar to the seismic crustal structures found at Atlantic fracture zones, and in particular to the structures found in profiles shot along the transform valley and near ridge-transform intersections. A magnetic anomaly chart seems to allow the possibility of several fracture zones one of which could intersect the centre of Line 5.As an alternative to the fracture zone hypothesis we show that if the ocean–continent transition in the Tagus Abyssal Plain is located at about 11°30'W, in a symmetric position with respect to the ocean–continent transition in the conjugate South Newfoundland Basin, then magnetic anomalies can be modelled simply by assuming sea-floor spreading west of 11°45'W at 10 mm yr-1 beginning at M11 time (133 Myr BP), and blocks of rifted continental crust to the east. The location of the proposed ocean–continent transition in the Tagus Abyssal Plain is marked by a well-defined N–S linear magnetic anomaly which is adjacent to the oldest sea-floor spreading block. East of the proposed ocean–continent transition there is an increase in the depth to basement similar to that found east of the ocean–continent transition in the Iberia Abyssal Plain and elsewhere. This model also allows us to explain why Purdy's (1975) seismic refraction line A–AR in the Tagus Abyssal Plain cannot be interpreted as a conventional reversed pair because most of Line A was shot over the ocean–continent transition zone and most of Line AR over thinned continental crust.Remarkably similar velocity/depth structures to that under Line 5 are found close to the ocean–continent transition zone off the whole of western Iberia, in areas which show no clear evidence of fracture zones. Therefore it appears more likely that the seismic structure of Line 5 is due to its proximity to the ocean–continent transition than to a local association with a fracture zone and further, that its structure is typical of this transition off the western margin of Iberia. We also suspect that the low upper mantle velocities associated with the ocean–continent transition indicate the widespread occurrence of serpentinized peridotite.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1365-246X.1992.tb00082.x

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4

Digitale Medien

Incidental findings on trauma ultrasonography (2000)

Pinheiro, L. W. ; McKenney, K. L. ; Rivas, L. ; [weitere]

Springer

Emergency radiology 7 (2000), S. 19-24

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ISSN: 1438-1435

Schlagwort(e): Key words Ultrasonography, emergency – Ultrasonography, abdominal – Trauma, blunt abdominal

Quelle: Springer Online Journal Archives 1860-2000

Thema: Medizin

Notizen: Abstract Purpose: To determine the prevalence of incidental findings detected on the focused abdominal sonogram for trauma. Methods: From November 1996 to February 1998, 1914 radiologist-assisted trauma ultrasound examinations were performed. Incidental findings were tabulated by retrospective review of the trauma radiology daily logbooks. Results: Incidental nontraumatic findings were detected in 160 (8.36 %) of the acutely injured patients. Most findings were benign, including echogenic liver, renal cysts, and cholelithiasis. However, significant pathology was detected in several patients, including renal masses, hepatic metastases, and gynecologic disease. Conclusion: The radiologist-assisted trauma ultrasound examination can provide valuable diagnostic information beyond the detection of free fluid. This may have important implications, as nonradiologists are increasingly involved in the practice of trauma ultrasonography. Even in the setting of trauma, significant occult pathology can be detected on a targeted ultrasound examination.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/s101400050005

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5

Digitale Medien

High sensitivity of detection of human malaria parasites by the use of nested polymerase chain reaction

Snounou, G. ; Viriyakosol, S. ; Xin Ping Zhu ; [weitere]

Amsterdam : Elsevier

Molecular & Biochemical Parasitology 61 (1993), S. 315-320

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ISSN: 0166-6851

Schlagwort(e): Diagnosis ; Epidemiology ; Mixed infection ; Plasmodium falciparum ; Plasmodium malariae ; Plasmodium ovale ; Plasmodium vivax ; Polymerase chain reaction ; [abr] PCR; polymerase chain reaction ; [abr] ssrRNA; small subunit ribosomal RNA

Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Thema: Biologie

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1016/0166-6851(93)90077-B

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6

Unbekannt

Microbial methane turnover at mud volcanoes of the Gulf of Cadiz. (2006)

Niemann, H. ; Duarte, J. ; Hensen, C. ; [weitere]

In: EPIC3Geochemica Cosmochemica Acta, 70, pp. 5336-5335

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Publikationsdatum: 2014-09-17

Repository-Name: EPIC Alfred Wegener Institut

Materialart: Article , peerRev

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7

Unbekannt

Multiple sources of hydrocarbon gases in mud volcanoes of the Gulf of Cadiz (SW Iberian Margin) – insights from a large organic geochemistry data set (2013)

Nuzzo, Marianne ; Hensen, Christian ; Schmidt, Mark ; [weitere]

In: [Poster] In: AAPG Annual Convention & Exhibition 2013, 19.-22.05.2013, Pittsburgh, USA .

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Publikationsdatum: 2013-12-19

Materialart: Conference or Workshop Item , NonPeerReviewed

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OceanRep: Poster

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8

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Morphotectonics and strain partitioning at the Iberia–Africa plate boundary from multibeam and seismic reflection data (2009)

Terrinha, P. ; Matias, L. ; Vicente, J. ; [weitere]

Elsevier

In: Marine Geology, 267 (3-4). pp. 156-174.

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Publikationsdatum: 2015-01-27

Beschreibung: The Gulf of Cadiz, off SW Iberia and the NW Moroccan margin, straddles the cryptic plate boundary between Africa and Eurasia, a region where the orogenic Alpine compressive deformation in the continental collision zone passes laterally to the west to strike-slip deformation. A set of new multibeam bathymetry, multi-channel and single-channel seismic data presented here image the main morphological features of tectonic origin of a significant part of the Gulf of Cadiz from the continental shelf to the abyssal plain. These morphotectonic features are shown to result from the reactivation of deeply rooted faults that changed their kinematics from the early Mesozoic rifting, through the Late Cretaceous–Paleogene collision, to the Pliocene–Quaternary thrusting and wrenching. The old faults control deep incised, more than 100 km long canyons and valleys. Several effects of neotectonics on deep water seabed are shown. These include: i) the complex morphology caused by wrenching on the 230 km long WNW–ESE faults that produced en echelon folds on the sediments; ii) the formation of up to 5 km wide crescent shaped scours at roughly 4 km water depth by reactivation of thrusts; iii) 10 km long creep folds on the continental slope; and iv) the formation of landslides on active fault escarpments. The present day deformation is partitioned on NE–SW thrusts and WNW–ESE to W–E strike-slip faults and is propagating northwards on N–S trending thrusts along the West Iberia Margin from 35.5°N to 38°N, which should be considered for seismic hazard.

Materialart: Article , PeerReviewed

Format: text

DOI: 10.1016/j.margeo.2009.09.012

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