scholarly journals Tertiary development of the Faeroe-Rockall Plateau based on reflection seismic data

1994 ◽  
Vol 41 ◽  
pp. 162-180
Author(s):  
L O. Baldreel ◽  
M.S. Andersen
Keyword(s):  
Seismic Data ◽  
Seismic Facies ◽  
Early Eocene ◽  
Ne Atlantic ◽  
Seismic Profiles ◽  
Norwegian Sea ◽  
Reflection Seismic ◽  
The North ◽  
Rockall Trough ◽  
Ne Atlantic Ocean

The Faeroe-Rockall Plateau is located in the NE Atlantic Ocean between Iceland and Scotland and is characterized by a late Paleocene-early Eocene basalt cover, which was extruded in association with the incipient opening of the NE Atlantic. The Faeroe-Rockall Plateau is separated from the NW European continental shelf by the Rockall Trough and the Faeroe­Shetland Channel, whose nature and age is still debated. Reflector configuration within the basalt allows volcanic seismic facies inteipretation to be carried out. The thickness of the basalt cover is estimated from reflection seismic data. Subbasalt geological structures are identified below subaerially extruded basalt on recently acquired as well as reprocessed seismic profiles. Overlying the basalt are early Eocene and younger Sediments. The distribution of these sedi- . ments is largely controlled by 1) the topography after the cessation of the volcanism, 2) the post volcanic subsidence of the area which is estimated from the depth to the breakpoints located on prim¥)' volcanic escaipments, 3) the Eocene-Miocene compressional tectonics which formed ridge& and minor basins, and 4) bottom currents of Norwegian Sea Deep Water (NSDW) which in the Neogene flowed into the North Atlantic south of the Greenland-Iceland-Faeroe-Scotland Ridg,e. A considerable part of the NSDW flows east and south of th

The syn-rift sedimentary cover of the North Biscay Margin (bay of Biscay): from new reflection seismic data

2002 ◽  
Vol 173 (6) ◽  
pp. 515-522 ◽  
Author(s):  
Isabelle Thinon ◽  
Jean-Pierre Réhault ◽  
Luis Fidalgo-González
Keyword(s):  
Seismic Data ◽  
Sedimentary Basin ◽  
Sedimentary Cover ◽  
Seismic Facies ◽  
Bay Of Biscay ◽  
Seismic Reflection Data ◽  
Reflection Seismic ◽  
The North ◽  
Reflection Data ◽  
Lower Aptian

Abstract The Armorican Basin is a deep sedimentary basin lying at the footside of the North Bay of Biscay. From previous scattered inadequate data, the age and nature of this basin, oceanic domain or deep part of the Armorican margin itself were largely speculated. From this new seismo-stratigraphic study based on a dense seismic cover, the sedimentation within the Armorican Basin is beginning in the Aptian times, during the last tectonic rifting episode of the margin. The first sediments formation identified as the « 3B layer » is characterised on the profiles by a chaotic and transparent seismic facies and was emplaced by slumping process when the margin collapsed, at the final rifting phase, just before the oceanic accretion. The new seismic reflection data give also some informations on the polyphased evolution of the North Biscay Margin during the rifting period. Two main events occurred during the Lower Cretaceous times (the first one is pre-Berriasian, the second is Aptian), separated by a quiet tectonic period including the Upper Berriasian and Lower Aptian times. The first event is responsible of the margin tectonic structuration in some blocks, the second of collapsing and the emplacement of the allochthonous sediments (3B layer) in the Armorican Basin.

Allopodocotyle margolisi n.sp. (Digenea: Opecoelidae) from the deep-sea fish Coryphaenoides (Chalinura) mediterraneus in the northeastern Atlantic

1995 ◽  
Vol 52 (S1) ◽  
pp. 90-94 ◽  
Author(s):  
David I. Gibson
Keyword(s):  
Atlantic Ocean ◽  
Deep Sea ◽  
Ne Atlantic ◽  
The North ◽  
Rockall Trough ◽  
Ne Atlantic Ocean ◽  
Sea Fish ◽  
Northeastern Atlantic ◽  
North Rockall Trough

An opecoelid digenean parasite, Allopodocotyle margolisi n.sp., is described from the macrourid fish Coryphaenoides (Chalinura) mediterraneus from benthopelagic waters of the North Rockall Trough, NE Atlantic Ocean. This is the first member of the genus to be recorded from deep-sea fishes. It is distinguished from its neritic congeners on the basis of features that include the arrangement of the testes, length of the cirrus-sac, and sucker-ratio. Its distinctness from other opecoelids from deep-sea fishes is also commented upon.

scholarly journals A new species of Ampharete (Annelida: Ampharetidae) from the West Shetland shelf (NE Atlantic Ocean), with two updated keys to the species of the genus in North Atlantic waters

2019 ◽  
Author(s):  
Julio Parapar ◽  
Juan MOREIRA ◽  
Ruth BARNICH
Keyword(s):  
North Atlantic ◽  
Small Body ◽  
New Taxon ◽  
Ne Atlantic ◽  
The West ◽  
The North ◽  
Joint Nature Conservation Committee ◽  
Ne Atlantic Ocean ◽  
Micro Morphology ◽  
A New Species

Ampharete oculicirrata sp. nov. (Annelida: Ampharetidae) is described from samples collected by the Joint Nature Conservation Committee and Marine Scotland Science, in the West Shetland Shelf NCMPA in the NE Atlantic. This species is characterised by a very small body size, thin and slender paleae, twelve thoracic and eleven abdominal uncinigers, presence of eyes both in the prostomium and the pygidium, the latter provided with a pair of long lateral cirri. The external micro-morphology of the new taxon was studied using scanning electron microscopy and compared with species described or reported from the North Atlantic. Two complementary keys to all species of Ampharete in the area are also provided.

Twelve years of vertical birefringence in nine‐component VSP data

Geophysics ◽  
2001 ◽  
Vol 66 (2) ◽  
pp. 582-597 ◽  
Author(s):  
Donald F. Winterstein ◽  
Gopa S. De ◽  
Mark A. Meadows
Keyword(s):  
Seismic Data ◽  
Azimuthal Anisotropy ◽  
Vertical Shear ◽  
S Wave ◽  
Seismic Profiles ◽  
Surface Reflection ◽  
Vertical Seismic Profiles ◽  
Reflection Seismic ◽  
San Andreas ◽  
Vsp Data

Since 1986, when industry scientists first publicly showed data supporting the presence of azimuthal anisotropy in sedimentary rock, we have studied vertical shear‐wave (S-wave) birefringence in 23 different wells in western North America. The data were from nine‐component vertical seismic profiles (VSPs) supplemented in recent years with data from wireline crossed‐dipole logs. This paper summarizes our results, including birefringence results in tabular form for 54 depth intervals in 19 of those 23 wells. In the Appendix we present our conclusions about how to record VSP data optimally for study of vertical birefringence. We arrived at four principal conclusions about vertical S-wave birefringence. First, birefringence was common but not universal. Second, birefringence ranged from 0–21%, but values larger than 4% occurred only in shallow formations (<1200 m) within 40 km of California’s San Andreas fault. Third, at large scales birefringence tended to be blocky. That is, both the birefringence magnitude and the S-wave polarization azimuth were often consistent over depth intervals of several tens to hundreds of meters but then changed abruptly, sometimes by large amounts. Birefringence in some instances diminished with depth and in others increased with depth, but in almost every case a layer near the surface was more birefringent than the layer immediately below it. Fourth, observed birefringence patterns generally do not encourage use of multicomponent surface reflection seismic data for finding fractured hydrocarbon reservoirs, but they do encourage use of crossed‐dipole logs to examine them. That is, most reservoirs were birefringent, but none we studied showed increased birefringence confined to the reservoir.

scholarly journals Reflexně seismický výzkum pozdně kenozoické zlomové tektoniky na vybraných lokalitách hornomoravského úvalu

2020 ◽  
Vol 27 (1-2) ◽  
Author(s):  
Ondřej Bábek ◽  
Zuzana Lenďáková ◽  
Tamás Tóth ◽  
Daniel Šimíček ◽  
Ondřej Koukal
Keyword(s):  
Low Cost ◽  
Seismic Facies ◽  
Gravity Gradients ◽  
Seismic Profiles ◽  
Low Velocity ◽  
Shallow Subsurface ◽  
Static Correction ◽  
Reflection Seismic ◽  
Weight Drop ◽  
Siliciclastic Sediments

We measured shallow reflection seismic profiles across the assumed faults in the Late Cenozoic (Pliocene – Holocene) Upper Morava Basin (UMB). The faults in the UMB are indicated by horst-and-graben morphology, differential thickness of Pliocene and Quaternary siliciclastic sediments, considerable gravity gradients a present-day seismicity. Four seismic lines, 380 to 860 m long (fixed geophone spread) were designed to cross the assumed faults at three sites, Mezice, Drahlov and Výšovice. The data were acquired by 24-channel ABEM Terraloc Mk-8 seismic system with PEG-40 accelerated weight drop source and processed by Sandmaier ReflexW and Halliburton Landmark ProMax® seismic processing software. The processing included application of filters (DC shift, scaled windowgain, bandpass frequency and muting), stacking using normal moveout constant velocity stack, additional application of subtrack-mean (dewow) filter, topographic correction and low velocity layer static correction. Distinct reflectors were detected up to 400 ms TWT, which corresponds to maximum depth of 280 and 350 m at 1400 and 1750 km.s-1 velocities, respectively. The observed reflection patterns were classified into three seismic facies, which were interpreted as crystalline rocks (Brunovistulicum) and/or well consolidated Paleozoic sedimentary rocks (SF1), unconsolidated Quaternary siliciclastic sediments (SF2) and semi-consolidated Neogene clays (SF3) based on the cores drilled in their close vicinity. Distinct faults were observed at the Drahlov and Výšovice 2 profile, which coincided with the observed topographic steps between the horsts and grabens. Presence of the fault at the Drahlov profile separating the Hněvotín Horst from the Lutín Graben was demonstrated by independent electrical resistivity tomography profile. On the other hand, another topographic step at the Mezice profile, between the Hněvotín Horst and Olomouc Graben, does not correspond to any seismic indication of a fault. The reflection seismic proved to be useful and relatively low-cost method to visualize the shallow subsurface geology in the Upper Morava Basin.

scholarly journals Deep Structure of the North Natal Valley (Mozambique) Using Combined Wide‐Angle and Reflection Seismic Data

2021 ◽  
Vol 126 (4) ◽  
Author(s):  
A. Leprêtre ◽  
P. Schnürle ◽  
M. Evain ◽  
F. Verrier ◽  
D. Moorcroft ◽  
...  
Keyword(s):  
Seismic Data ◽  
Deep Structure ◽  
Wide Angle ◽  
Reflection Seismic ◽  
The North

SEISMIC DATA PROBLEMS ON COASTAL LIMESTONE, W.A.

1969 ◽  
Vol 9 (1) ◽  
pp. 136
Author(s):  
D. D. Taylor
Keyword(s):  
Seismic Data ◽  
The South ◽  
Reflection Seismic ◽  
The North ◽  
Great Portion

The surface Coastal Limestone in the Perth basin extends from Cape Leeuwin in the South to Geraldton in the north forming a strip along the coast up to 15 miles wide. Over a great portion of this area the reflection seismic results are unreliable. Seismic studies on the limestone disclose some aspects of the problem and indicate ways to improve the quality of the data.

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