scholarly journals Structures of the Kirkuk Embayment, northern Iraq: Foreland structures or Zagros Fold Belt structures?

GeoArabia ◽  
2010 ◽  
Vol 15 (4) ◽  
pp. 147-188 ◽  
Author(s):  
W. Norman Kent
Keyword(s):  
Cross Sections ◽  
Seismic Data ◽  
Field Data ◽  
Fault System ◽  
Normal Faults ◽  
Fold Belt ◽  
Potential Field Data ◽  
Northern Iraq ◽  
Fault Propagation Fold ◽  
Zagros Orogen

ABSTRACT Several anticlines in northern Iraq and Syria have been studied through the construction of balanced and restored cross sections. Based upon structural analysis, each of the studied anticlines is a fault-propagation fold that developed due to Zagros-related, recent inversion of much older normal faults. Studies on the Iranian part of the Zagros Fold Belt have suggested that the regional variation in the character of the fold belt is related to weak detachment surfaces in the stratigraphic section, primarily the decollement developed near the top of the Hormuz Salt where the salt is present. No evidence for Hormuz Salt has been found within the Kirkuk Embayment, and although detachment surfaces contribute the area’s structural character, the prominent folds seem to originate mainly from basement involved faults. Two distinct inversion structural trends exist: E-W system and a NW system of inverted grabens. In Syria, several of the faults associated with the EW-trending system cut the basement on seismic data and have stratigraphic relationships indicating that their displacement originated in the Neoproterozoic. In Iraq, the thicker sedimentary section did not allow the deep parts of the fault systems to be imaged on the available seismic. While the NW fault system of inverted normal faults could be linked to the Zagros Orogen by a decollement surface in the sedimentary section, regional relationships and potential-field data suggest that this trend also is basement involved and has a Neoproterozoic origin.

scholarly journals Structural cross sections through the Corinth-Patras detachment fault-system in Northern Peloponnesus (Aegean Arc, Greece)

2001 ◽  
Vol 34 (1) ◽  
pp. 235 ◽  
Author(s):  
N. FLOTTÉ ◽  
D. SOREL
Keyword(s):  
Cross Sections ◽  
Detachment Fault ◽  
Fault System ◽  
Normal Faults ◽  
Field Observations ◽  
Structural Mapping ◽  
The North ◽  
Gulf Of Corinth ◽  
Aegean Arc

Structural mapping in northern Peloponnesus reveals the emergence of an E-W striking, more than 70km long, low angle detachment fault dipping to the north beneath the Gulf of Corinth. This paper describes four north-south structural cross-sections in northern Peloponnesus. Structural and sedimentological field observations show that in the studied area the normal faults of northern Peloponnesus branch at depth on this major low angle north-dipping brittle detachment. The southern part of the detachment and the related normal faults are now inactive. To the north, the active Helike and Aigion normal faults are connected at depth with the seismically active northern part of the detachment beneath the Gulf of Corinth.

Three-dimensional depth-to-basement modelling based on seismic and potential field data – basement configuration in the westernmost Polish Outer Carpathians

2020 ◽  
Author(s):  
Mateusz Mikołajczak ◽  
Jan Barmuta ◽  
Małgorzata Ponikowska ◽  
Stanislaw Mazur ◽  
Krzysztof Starzec
Keyword(s):  
Qualitative Analysis ◽  
Cross Sections ◽  
Potential Field ◽  
Field Data ◽  
Gravity Data ◽  
Three Dimensional ◽  
Magnetic Data ◽  
Gravity Inversion ◽  
Potential Field Data ◽  
Outer Carpathians

<p>The Silesian Nappe in the westernmost part of the Polish Outer Carpathians Fold and Thrust Belt exhibits simple, almost homoclinal character. Based on the field observations, a total stratigraphic thickness of this sequence equals to at least 5400 m. On the other hand, the published maps of the sub-Carpathian basement show its top at depths no greater than 3000 m b.s.l. or even 2000 m b.s.l. in the southern part of the Silesian Nappe. Assuming no drastic thickness variations within the sedimentary sequence of the Silesian Nappe, such estimates of the basement depth are inconsistent with the known thickness of the Silesian sedimentary succession. The rationale behind our work was to resolve this inconsistency and verify the actual depth and structure of the sub-Carpathian crystalline basement along two regional cross-sections. In order to achieve this goal, a joint 2D quantitative interpretation of gravity and magnetic data was performed along these regional cross-sections. The interpretation was supported by the qualitative analysis of magnetic and gravity maps and their derivatives to recognize structural features in the sub-Carpathian basement. The study was concluded with the 3D residual gravity inversion for the top of basement. The cross-sections along with the borehole data available from the area were applied to calibrate the inversion.</p><p>In the westernmost part of the Polish Outer Carpathians, the sub-Carpathian basement comprises part of the Brunovistulian Terrane. Because of great depths, the basement structure was investigated mainly by geophysical, usually non-seismic, methods. However, some deep boreholes managed to penetrate the basement that is composed of Neoproterozoic metamorphic and igneous rocks. The study area is located within the Upper Silesian block along the border between Poland and Czechia. There is a basement uplift as known mainly from boreholes, but the boundaries and architecture of this uplift are poorly recognized. Farther to the south, the top of the Neoproterozoic is buried under a thick cover of lower Palaeozoic sediments and Carpathian nappes.</p><p>Our integrative study allowed to construct a three-dimensional map for the top of basement the depth of which increases from about 1000 m to over 7000 m b.s.l. in the north and south of the study area, respectively. Qualitative analysis of magnetic and gravity data revealed the presence of some  basement-rooted faults delimiting the extent of the uplifted basement. The interpreted faults are oriented mainly towards NW-SE and NE-SW. Potential field data also document the correlation between the main basement steps and important thrust faults.</p><p> </p><p>This work has been funded by the Polish National Science Centre grant no UMO-2017/25/B/ST10/01348</p>

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>

Simultaneous inversion modeling of gravity and aeromagnetic data applied to a geothermal study in Utah

Geophysics ◽  
1984 ◽  
Vol 49 (8) ◽  
pp. 1327-1337 ◽  
Author(s):  
Laura F. Serpa ◽  
Kenneth L. Cook
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Hot Springs ◽  
Normal Faults ◽  
Geothermal Resource ◽  
Aeromagnetic Data ◽  
Potential Field Data ◽  
Simultaneous Inversion ◽  
Geothermal Potential ◽  
Deep Faults

Aeromagnetic and gravity surveys were conducted in the Black Rock Desert, Utah to assess the geothermal potential of the Meadow‐Hatton Known Geothermal Resource Area (KGRA). The presence of basalt flows less than 1000 yr old and a 400 000 yr old rhyolite dome suggested that a hot intrusive body, which should be detectable in both types of potential field data, may provide the heat source for hot springs in the study area. A simultaneous inversion computer program was developed as part of this study to model these potential field data. The resulting models indicate hydrothermal alteration about the hot springs extending to a depth of approximately 1 km. Normal faults above a low‐angle detachment appear to reach a depth of approximately 4 km and provide a path for the circulation of groundwater in the area. No evidence for a buried igneous body was found in the study area, and it is therefore concluded that the migration of fluids along the deep faults is sufficient to account for the water temperatures estimated for the KGRA.

scholarly journals Implications of Tectonic Anomalies From Potential Field Data in Some Parts of Southeast Nigeria.

2021 ◽  
Author(s):  
STEPHEN EGUBA EKWOK ◽  
Anthony Effiong Akpan ◽  
Ogiji-Idaga Martins Achadu ◽  
Christian Atelwhobel Ulem
Keyword(s):  
Potential Field ◽  
High Frequency ◽  
Short Wavelength ◽  
Field Data ◽  
Low Frequency ◽  
Normal Faults ◽  
Tectonic Structures ◽  
Potential Field Data ◽  
Igneous Intrusions ◽  
Basin Topography

Abstract Tectonic structures controlling mineralization in some parts of Southeast Nigeria were evaluated using airborne potential field data. High and low frequency filters and depth determination tools were adopted to evaluate short and long wavelength anomalies, resolve the spatial spreading of igneous intrusions, depths to geologic sources and basin topography. The high frequency results exhibited high concentration of short wavelength anomalies in the Obudu Plateau and Ikom-Mamfe Rift. The underlying main tectonics of the area elucidated by the low frequency results caused the widespread occurrences of short wavelength geologic structures that are revealed by the high frequency maps. The study area is characterized by comparatively thin (~13.0 to <3000 m) sedimentation. The observed thin thickness is as a result of the massive Precambrian basement outcrops in some locations in the Obudu Plateau and the proliferation of igneous intrusions within this part of the Lower Benue Trough. The 2-D models showed the undulating nature of the underlying basin topography, the location of intrusions, domal structures and related normal faults. The locations and neighbourhood of intrusions and/or short wavelength structures are viable sites for lead-zinc-barite, brine and metallogenic minerals.

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

Inversion structures in a foreland domain: Seismic examples from the Italian Adriatic Sea

2015 ◽  
Vol 3 (4) ◽  
pp. SAA161-SAA176 ◽  
Author(s):  
Paolo Pace ◽  
Vittorio Scisciani ◽  
Fernando Calamita ◽  
Robert W. H. Butler ◽  
David Iacopini ◽  
...  
Keyword(s):  
Cross Sections ◽  
Seismic Data ◽  
Adriatic Sea ◽  
Forward Modeling ◽  
Normal Faults ◽  
Regional Structure ◽  
Thrust Belts ◽  
Structural Inversion ◽  
Half Graben ◽  
Adriatic Region

Positive structural inversion within foreland domains ahead of thrust belts can create structures with significant hydrocarbon potential in mature and underexplored areas. Within this context, the Adriatic region represents a well-established hydrocarbon province constituting a foreland domain bounded by the Apennines, Southern Alps, and Dinaric fold-and-thrust belts. Newly reprocessed regional 2D seismic data and a renewed exploration interest in the area motivate a reappraisal of the regional structure and stratigraphy of the deformed Central Adriatic region of Italy (i.e., the Mid-Adriatic Ridge). Here, we developed and discussed examples of inversion structures that have different structural styles. The structural interpretations displayed on time-to-depth converted profiles had been validated by 2D structural-kinematic balancing and forward modeling. Our aim was to better define the geometry, style, and timing of the analyzed inversion-related folds. Positive inversion structures appeared locally as asymmetric harpoon-shaped anticlines riding over high-angle blind thrusts. More commonly, inversion structures were symmetric anticlines formed above conjugate faults. Retrodeformed cross sections showed that positive inversion involved symmetric graben and asymmetric half-graben that originated during the Triassic and Jurassic. That these inversion structures developed during basement-involved thrusting, as suggested for the Adriatic in general, was consistent with forward modeling. Regionally, the contractional structures belonging to the Mid-Adriatic Ridge can be explained in terms of intraplate deformation that chiefly acted through reactivation of Mesozoic normal faults.

Sign in / Sign up

Export Citation Format

Share Document