Geological and geophysical structural features of Predverkhoyansky Foreland Basin and neighbouring areas: data from new along-river 2D CDP seismic survey line and reinterpretation of legacy data

2021 ◽  
pp. 55-73
Author(s):  
Mariya Shaporina ◽  
Evgenii Mosyagin ◽  
Oleg Sadur ◽  
Vladimir Bespechnyi
Keyword(s):  
Foreland Basin ◽  
Structural Features ◽  
Seismic Survey ◽  
Survey Line ◽  
Legacy Data

scholarly journals Basement Structure and Styles of Active Tectonic Deformation in Central Interior Alaska

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 127
Author(s):  
Nilesh C. Dixit ◽  
Catherine Hanks
Keyword(s):  
Crustal Structure ◽  
Foreland Basin ◽  
Active Regions ◽  
Structural Features ◽  
Tectonic Deformation ◽  
Block Rotation ◽  
High Concentration ◽  
Intraplate Earthquakes ◽  
Interior Alaska ◽  
Nenana Basin

Central Interior Alaska is one of the most seismically active regions in North America, exhibiting a high concentration of intraplate earthquakes approximately 700 km away from the southern Alaska subduction zone. Seismological evidence suggests that intraplate seismicity in the region is not uniformly distributed, but concentrated in several discrete seismic zones, including the Nenana basin and the adjacent Tanana basin. Although the location and magnitude of the seismic activity in both basins are well defined by a network of seismic stations in the region, the tectonic controls on these intraplate earthquakes and the heterogeneous nature of Alaska’s continental interior remain poorly understood. We investigated the crustal structure of the Nenana and Tanana basins using available seismic reflection, aeromagnetic and gravity anomaly data, supplemented by geophysical well logs and outcrop data. We developed nine new two-dimensional forward models to delineate internal geometries and the crustal structure of Alaska’s interior. The results of our study demonstrates a strong crustal heterogeneity beneath both basins. The Tanana basin is a relatively shallow (up to 2 km) asymmetrical foreland basin with its southern, deeper side controlled by the northern foothills of the Central Alaska Range. Northeast-trending left lateral strike-slip faults within the Tanana basin are interpreted as a zone of clockwise crustal block rotation. The Nenana basin has a fundamentally different geometry. It is a deep (up to 8 km), narrow transtensional pull-apart basin that is deforming along the left-lateral Minto Fault. This study identifies two distinct modes of current tectonic deformation in Central Interior Alaska and provides a basis for modeling the interplay between intraplate stress fields and major structural features that potentially influence the generation of intraplate earthquakes in the region.

A PROPOSED GEOPHYSICAL PROGRAM OF EXPLORATION FOR NEBRASKA AND THE DAKOTAS

Geophysics ◽  
1936 ◽  
Vol 1 (2) ◽  
pp. 189-195
Author(s):  
John H. Wilson
Keyword(s):  
Structural Features ◽  
Resolving Power ◽  
Seismic Survey ◽  
Geological Information

The known geological information, particularly with reference to possible oil‐producing horizons, is discussed briefly. A method is proposed whereby the area is subjected to a reconnaissance seismic survey to determine the location of the major structural features, followed by other methods of successively higher resolving power in the favorable areas outlined by the reconnaissance.

KINEMATICAL MODEL FOR FORMING THE SIMEAN LOW OF THE URALIAN FORELAND BASIN

2018 ◽  
pp. 23-32
Author(s):  
Al. V. Tevelev ◽  
I. A. Prudnikov ◽  
Ark. V. Tevelev ◽  
A. O. Khotylev ◽  
E. A. Volodina
Keyword(s):  
Foreland Basin ◽  
Shear Zones ◽  
Structural Features ◽  
The North ◽  
Lateral Extrusion ◽  
Kinematical Model

In this work we reported the structural features and mechanism of the formation of the Simskaya low of the Uralian foreland basin, besides the Karatau-Suleyman block as a whole. This block has the shape of a wedge, so with a general latitudinal compression, it experienced lateral extrusion to the north along the conjugated shear zones. This factor determined the local situation of meridional compression and latitudinal tension. In the central part of the block, the latitudinal stretching was compensated for by gradual deflection, which led to the formation of the Simskaya low.

Lithospheric buckling dominates the Cenozoic subsidence of the Qaidam Basin, NE Tibetan Plateau

2021 ◽  
Author(s):  
Hu Xiaoyi ◽  
Wu Lei
Keyword(s):  
Tibetan Plateau ◽  
Qaidam Basin ◽  
Foreland Basin ◽  
Structural Features ◽  
Tectonic Subsidence ◽  
The Tibetan Plateau ◽  
Basin Formation ◽  
Orogenic Belts ◽  
The Impact ◽  
First Time

<p>Flexural basins are the common geological feature in convergent settings, and usually regarded as the result of flexural subsidence of the margins of under-thrusting cratons in response to the gravitational load of over-riding orogens. This process usually causes the fastest tectonic subsidence and thickest orogenic-related deposits in the basin margins adjacent to the orogens, such as India Foreland Basin in front of the Himalaya. The Qaidam Basin, which is the largest sedimentary basin within the Tibetan Plateau interior, was once interpreted to belong to this type and form by flexural subsidence on its south and north margins in response to loading of the Qiman Tagh and the South Qilian Shan orogenic belts, respectively. However, the latest studies present sedimentary and structural features that contrast to a typical foreland basin. These features include (1) depocenters being located along the central axis, rather than the margins, with thickest sediments up to 15 km, and (2) development of many high-angle reverse faults, rather than thin-skinned thrusts, to generate upper-crustal shortening as low as 10-15% (20 – 30 km), indicating that the widths of the orogenic belts juxtaposed atop the basin margins are limited. These features cannot be explained by the flexural subsidence of basin margins and/or sediment load. Herein, we investigate the impact of lithospheric buckling, which has been ignored in most studies of basin formation in compressional settings, on the tectonic subsidence of the Qaidam Basin through numerical simulation based on finite elastic plate model. We first use the flexural backstripping method to calculate the tectonic subsidence of the Cenozoic basement across the Qaidam Basin. And then, we simulate the tectonic subsidence caused by (1) gravitational load of orogenic belts alone, and (2) combined gravitational load and lithosphere buckling. The result shows that the simulated tectonic subsidence curve fits well with the real one only when considering the effect of lithospheric buckling that accounts for >90% tectonic subsidence. Our finding indicates for the first time that lithospheric buckling is also an important mechanism for the subsidence of intramountain basins like the Qaidam Basin, and should not be ignored when studying lithospheric-scale deformation across large orogenic belts.</p>

Detailed basin structure and tectonic evolution of the Midcontinent Rift System in eastern Lake Superior from reprocessing of GLIMPCE deep reflection seismic data

1994 ◽  
Vol 31 (4) ◽  
pp. 629-639 ◽  
Author(s):  
C. Samson ◽  
G. F. West
Keyword(s):  
Lake Superior ◽  
Detailed Examination ◽  
Structural Features ◽  
Seismic Survey ◽  
Rift System ◽  
Midcontinent Rift ◽  
Reflection Seismic ◽  
Basic Wavelet ◽  
Midcontinent Rift System ◽  
In The Beginning

Line F of the GLIMPCE deep marine reflection seismic survey has been reprocessed according to a data-dependent strategy aimed at enhancing the fine structural features of the Midcontinent Rift System in eastern Lake Superior. The processing sequence was specially designed to attenuate first-order water reverberations and to reduce the excessive oscillatory character of the basic wavelet. A detailed examination of the final migrated stacked section reveals that, beneath line F, the Midcontinent Rift System is an almost perfectly symmetric syncline. The structure appears to have formed in the beginning by the extrusion of lavas on a horizontal platform subsiding without major deformation. The initial phase was followed by local crustal sagging in the centre. The transition is marked by a major reflector, which is hypothesized to correspond to the boundary between reverse- and normal-polarity volcanics in eastern Lake Superior. Integrating the results of several recent investigations, a five-stage evolutionary scenario is proposed for the Midcontinent Rift System in eastern Lake Superior: (1) onset of extrusive volcanism, (2) platform subsidence, (3) local crustal sagging, (4) deposition of postrift sediments, and (5) tectonic inversion.

Seismic stratigraphy of the East-Siberian and Chukchi seas as a key to the Amerasia Basin stratigraphy end evolution

2020 ◽  
Author(s):  
Kseniia Startseva ◽  
Anatoly Nikishin
Keyword(s):  
Foreland Basin ◽  
Sedimentary Basins ◽  
Geological Structure ◽  
Seismic Survey ◽  
Normal Faults ◽  
Seismic Profiles ◽  
The North ◽  
Sea Bottom ◽  
Reported Study ◽  
Bottom Sampling

<p>Based on new seismic survey, offshore drilling and geological structure of the adjacent onshore a new model of geological evolution of sedimentary basins of the East-Siberian and Chukchi seas since the Mesozoic has been constructed. The main stages of their tectonic history are highlighted: 1) forming of the foreland basin in Jurassic – Early Creatceous time; 2) synrift extension in Aptian-Albian time; 3) start of postrift subsidence in Later Cretaceous; 4) uplift and deformations at the turn of Cretaceous and Paleogene, start of forming of the thick (up to 4-6 km) clinoform complex; 5) episode of synrift extension in Middle-Later Eocene, forming of the system of multiple low-amplitude normal faults; 6) inversion deformations in Oligocene-Miocene; 7) relatively calm tectonic conditions in Neogene-Quaternary time. Boundaries of the interpreted seismic complexes corresponding to these stages has been extended to the entire Amerasia basin with regards to the ages of magnetic anomalies in the Gakkel Ridge and sea-bottom sampling on the Mendeleev Rise. Volcanic areas of the De Long Islands and the North Wrangel High has been traced on the seismic profiles toward Mendeleev Rise and Podvodnikov Basin and dated as ±125 Ma. According to the seismic interpretation, the age of the Podvodnikov and Toll basins is not older than Aptian. The reported study was funded by RFBR and NSFB, project number 18-05-70011, 18-05-00495 and 18-35-00133.</p>

scholarly journals Structural Features and Evolution of the Northwestern Sichuan Basin: Insights From Discrete Numerical Simulations

2021 ◽  
Vol 9 ◽  
Author(s):  
Wenqiao Xu ◽  
Hongwei Yin ◽  
Dong Jia ◽  
Changsheng Li ◽  
Wei Wang ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Sichuan Basin ◽  
Lower Layer ◽  
Foreland Basin ◽  
Middle Layer ◽  
Lower Triassic ◽  
Structural Features ◽  
Tectonic Deformation ◽  
Thrust Front ◽  
Rapid Uplift

The northwestern Sichuan Basin has experienced Meso-Cenozoic intracontinental compressional tectonic processes and formed multi-detachment stratigraphic distribution of foreland basins and fold-thrust belts, which have caused complicated structural deformations in the deep buried layers. Rapid uplift with accelerated erosion and two sets of detachments in the Lower Triassic and Lower Cambrian controlled the multilevel deformation structure. We conducted discrete numerical simulations with double weak detachments and erosion under extrusion conditions in order to examine the mechanics and kinematics of the frontalpiedmont zones of the NW Sichuan Basin. The following findings were made. (1) With continuous compression, the weak detachments promoted the decoupled and ladder-like deformation of the thrust belt, where the deformation above the slip layer extended further than it did below it. Rapid uplift and erosion at the thrust front contributed to the formation of a passive roof fault and a monocline in the upper layer, a series of forward and backward thin-skinned thrust-buried structures in the middle layer sandwiched between two weak detachments and stacking structures in the lower layer. (2) Erosion effectively prevents the deformation from propagating above the upper detachment, but can advance a horizontal transition in the deformation style generated within the middle brittle layer: from oblique and tight fault propagation folds to symmetrical, wide, and gentle detachment folds. (3) The model results consistent with tectonic deformation in the NW Sichuan Basin indicate a possible evolutionary mechanism under compression. There is hierarchical deformation of uncoordinated contraction controlled by the Lower Triassic and Early Cambrian weak layers, with the characteristics of the shallow monocline, the middle thin-skinned thrusts, and the deeper basement-involved folds. Continuous compression contributed a sequential pattern of steps as a whole, from the frontalpiedmont zones to the foreland basin, autochthonous stacking thrusts, and the huge buried structure in the NW Sichuan Basin. During the Himalayan period, syntectonic erosion along with the uplifted thrust front maintained the development of a passive-roof duplex and a huge forward buried structure.

Lessons Learned From the World's Largest Continuous Onshore and Offshore 3D Seismic Survey

2021 ◽  
Author(s):  
Saif Ali Al Mesaabi ◽  
Guillaume Marie Cambois ◽  
James Cowell ◽  
David Arnold ◽  
Mohamed Fawzi Boukhanfra ◽  
...  
Keyword(s):  
Low Frequency ◽  
High Energy ◽  
Lessons Learned ◽  
Seismic Survey ◽  
3D Seismic ◽  
Low Frequencies ◽  
The Status ◽  
Seismic Acquisition ◽  
Abu Dhabi Emirate ◽  
Legacy Data

Abstract In 2017 ADNOC decided to cover the entire Abu Dhabi Emirate, onshore and offshore, with high- resolution and high-fold 3D seismic. Acquisition of the world's largest continuous seismic survey started in late 2018 and is around 77% complete at the time of writing. Data processing is well under way and interpretation of the first delivered 3D cubes is ongoing. Now is an opportune time to review the status of this gigantic project and draw preliminary lessons. Comparison with legacy data shows a massive improvement in deep imaging, which was one of the main objectives of this survey. The basement can clearly be interpreted, while it is hardly visible on legacy data being covered with high energy multiples. A thorough analysis demonstrated that increased offset is the main reason for the uplift. The large fold and the low frequency sweep also help recover signal down to 3 Hz. This extends the bandwidth in the low frequencies by one to two octaves compared to legacy data, which tremendously benefits structural interpretation and stratigraphic inversion.

Electron microscopy and diffraction studies of polyimides

1983 ◽  
Vol 41 ◽  
pp. 28-29
Author(s):  
O.C. de Hodgins ◽  
K. R. Lawless ◽  
R. Anderson
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Structural Features ◽  
Inert Atmosphere ◽  
Polyimide Films ◽  
Resolution Electron ◽  
The Matrix ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns ◽  
Polymeric Samples

Commercial polyimide films have shown to be homogeneous on a scale of 5 to 200 nm. The observation of Skybond (SKB) 705 and PI5878 was carried out by using a Philips 400, 120 KeV STEM. The objective was to elucidate the structural features of the polymeric samples. The specimens were spun and cured at stepped temperatures in an inert atmosphere and cooled slowly for eight hours. TEM micrographs showed heterogeneities (or nodular structures) generally on a scale of 100 nm for PI5878 and approximately 40 nm for SKB 705, present in large volume fractions of both specimens. See Figures 1 and 2. It is possible that the nodulus observed may be associated with surface effects and the structure of the polymers be regarded as random amorphous arrays. Diffraction patterns of the matrix and the nodular areas showed different amorphous ring patterns in both materials. The specimens were viewed in both bright and dark fields using a high resolution electron microscope which provided magnifications of 100,000X or more on the photographic plates if desired.

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