Relationship between salt and crustal tectonics in the Sørvestsnaget Basin, SW Barents Sea

2020 ◽  
Author(s):  
Gaia Travan ◽  
Benjamin Bellwald ◽  
Sverre Planke ◽  
Virginie Gaullier ◽  
Dwarika Maharjan ◽  
...  
Keyword(s):  
Seismic Data ◽  
Potential Field ◽  
Field Data ◽  
Barents Sea ◽  
Hydrocarbon Exploration ◽  
Salt Tectonics ◽  
Potential Field Data ◽  
The Barents Sea ◽  
Western Side ◽  
Seismic Anomalies

<p>The geology of the Barents Sea has been widely studied because of the interest for hydrocarbon exploration. Our study focuses on the SW Barents Sea, on the western side of the Senja Ridge in the Sørvestsnagets Basin, which is still a less deciphered area. Located at the limit of the continental shelf, this deep Cretaceous basin is characterized by a several-kilometer-thick sequence of Cenozoic sediments locally influenced by salt structures. Because of the peculiar rheological characteristics of salt, the deposition of evaporites during Permo-Carboniferous times still represents a key aspect to deeply understand the geological setting because salt tectonics considerably affects the brittle sedimentary cover.</p><p>5,500 km<sup>2</sup> of high-quality 3D seismic data, integrated with potential field data and existing wells, led to the interpretation of the main horizons and unconformities in the sedimentary sequence, with focus on the salt structures.</p><p>The top of the salt is characterized by a strong positive-amplitude reflection in the seismic data, and has been interpreted with a line spacing of 100 m. Subsequent gridding of the interpreted horizon to a bin size of 12.5 m highlights that the geomorphology for the top of the three salt structures is particularly complex, with presence of salt horns and development of minibasins above the salt. Integration of potential field data shows a strong correlation between salt structures and low values in Bouguer-Gravity anomalies. Different families of faults related to salt and to crustal tectonics have been mapped, and strong seismic anomalies related to faults above the salt structures are identified at multiple stratigraphic levels. Part of these faults have been active until 20 000 years ago, and are rarely active at present day.</p><p>The three salt structures interpreted on the western side of the Senja Ridge have a total extent of around 800 km<sup>2</sup> and are mainly the consequence of different pulses of reactive diapirism, due to several diachronous rifting events during the opening of the Barents Sea. After the opening of the Sørvestsnagets Basin, salt tectonics continued and was influenced by crustal movements and glacial sedimentation and erosion in this pull-apart basin setting.</p><p>The presence of the strong seismic anomalies above the salt structures is interpreted as gas accumulations, which makes this topic of particular interest for the future development of the oil and gas industry of the SW Barents Sea.</p>

Revealing tectonic evolution across the Northeastern Flemish Cap-Goban Spur margin

2020 ◽  
Author(s):  
Pei Yang ◽  
J.Kim Welford
Keyword(s):  
Seismic Data ◽  
Potential Field ◽  
Field Data ◽  
Velocity Structure ◽  
Crustal Thickness ◽  
Borehole Data ◽  
Seismic Reflection Data ◽  
Potential Field Data ◽  
Shelf Slope ◽  
Goban Spur

<p>In past years, a good understanding of the structure and tectonics of the Flemish Cap and the Goban Spur margin has been obtained based on seismic data, potential field data, and borehole data. However, due to limited data coverage and quality, the rift-related domains along the margin pair have remained poorly defined and their architecture has been primarily delineated on the basis of a small number of co-located 2-D seismic profiles. In addition, according to previous studies, the geophysical characteristics (e.g. velocity structure, crustal thickness, seismic patterns, etc.) across both the margins are strikingly different. Furthermore, from restored models of the southern North Atlantic, some scholars argue against the linkage of the Goban Spur and the Flemish Cap, questioning the widely-accepted “conjugate” relationship of the two margins. However, these restored models are mainly dependent on potential field data analysis, lacking seismic constraints, particularly for the Irish Atlantic Margin.</p><p>In this study, new long offset 2D multichannel seismic data, acquired in 2013 and 2014 by Eni Ireland for the Department of Communications, Climate Action & Environment of Ireland, cover the shelf, slope, and deepwater regions of the offshore Irish Altlantic margin. Combining these with seismic reflection data at the NE Flemish Cap, seismic refraction data, DSDP drilling sites, gravity and magnetic maps, crustal thickness maps, and oceanic isochrones, we integrate all constraints together to characterize the structure and evolution of both margins. These geophysical data reveal significant along-strike structural variations along both margins, and aid to delimit five distinct crustal zones related to different rifting stages and their regional extents. The geometries of each crustal domain are variable along the margin strike, probably suggestive of different extension rates during the evolution of the margin and/or inherited variations in crustal composition and rheology. Particularly, the along-strike exhumed serpentinized mantle domain of the Goban Spur margin spans a much wider (~ 42 - 60 km) area while it is much narrower (~25 km) at the NE Flemish Cap margin. In the exhumed domain, only peridotite ridges are observed at the Flemish Cap, while both peridotite ridges and a wide region of exhumed mantle with deeper basement are observed at the Goban Spur, indicative of a more complex evolutionary model than previously thought for both margins. Plate reconstruction of the Goban Spur and the Flemish Cap using GPlates reveals asymmetry in their crustal architectures, likely due to rift evolution involving more 3-D complexity than can be explained by simple 2-D extensional kinematics. In spite of uncertainties, the crustal architecture comparison between the two margins provides 3D seismic evidence related to the temporal and spatial rifting evolution on both sides.</p>

The Congo Basin: Subsurface structure interpreted using potential field data and constrained by seismic data

2021 ◽  
pp. 103611
Author(s):  
Francesca Maddaloni ◽  
Carla Braitenberg ◽  
Mikhail K. Kaban ◽  
Magdala Tesauro ◽  
Damien Delvaux
Keyword(s):  
Seismic Data ◽  
Potential Field ◽  
Field Data ◽  
Congo Basin ◽  
Subsurface Structure ◽  
Potential Field Data

Basement inheritance and salt structures in the SE Barents Sea: Insights from new potential field data

2018 ◽  
Vol 119 ◽  
pp. 82-106 ◽  
Author(s):  
Laurent Gernigon ◽  
Marco Brönner ◽  
Marie-André Dumais ◽  
Sofie Gradmann ◽  
Arne Grønlie ◽  
...  
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Barents Sea ◽  
Potential Field Data

Improved salt imaging in a basin context by high resolution potential field data: Nordkapp Basin, Barents Sea

2014 ◽  
Vol 62 (3) ◽  
pp. 615-630 ◽  
Author(s):  
Christopher Stadtler ◽  
Christine Fichler ◽  
Ketil Hokstad ◽  
Eva Andrea Myrlund ◽  
Susann Wienecke ◽  
...  
Keyword(s):  
High Resolution ◽  
Potential Field ◽  
Field Data ◽  
Barents Sea ◽  
Potential Field Data

An improved approach for detecting the locations of the maxima in interpreting potential field data

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Luan Thanh Pham ◽  
Ozkan Kafadar ◽  
Erdinc Oksum ◽  
Ahmed M. Eldosouky
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Potential Field Data

Adaptive sampling of potential-field data: A direct approach to compressive inversion

Geophysics ◽  
2014 ◽  
Vol 79 (1) ◽  
pp. IM1-IM9 ◽  
Author(s):  
Nathan Leon Foks ◽  
Richard Krahenbuhl ◽  
Yaoguo Li
Keyword(s):  
Potential Field ◽  
Adaptive Sampling ◽  
Field Data ◽  
Computational Cost ◽  
Large Field ◽  
Magnetic Data ◽  
Data Sampling ◽  
Data Types ◽  
Data Set ◽  
Potential Field Data

Compressive inversion uses computational algorithms that decrease the time and storage needs of a traditional inverse problem. Most compression approaches focus on the model domain, and very few, other than traditional downsampling focus on the data domain for potential-field applications. To further the compression in the data domain, a direct and practical approach to the adaptive downsampling of potential-field data for large inversion problems has been developed. The approach is formulated to significantly reduce the quantity of data in relatively smooth or quiet regions of the data set, while preserving the signal anomalies that contain the relevant target information. Two major benefits arise from this form of compressive inversion. First, because the approach compresses the problem in the data domain, it can be applied immediately without the addition of, or modification to, existing inversion software. Second, as most industry software use some form of model or sensitivity compression, the addition of this adaptive data sampling creates a complete compressive inversion methodology whereby the reduction of computational cost is achieved simultaneously in the model and data domains. We applied the method to a synthetic magnetic data set and two large field magnetic data sets; however, the method is also applicable to other data types. Our results showed that the relevant model information is maintained after inversion despite using 1%–5% of the data.

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