Cenozoic crustal deformation of the offshore Burgos basin region (NE Gulf of Mexico). A new interpretation of deep penetration multichannel seismic reflection lines

2008 ◽  
Vol 179 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Charlotte Le Roy ◽  
Claude Rangin
Keyword(s):  
Gulf Of Mexico ◽  
Fault Zone ◽  
Coastal Plain ◽  
Crustal Deformation ◽  
Seismic Reflection ◽  
Tectonic Activity ◽  
Normal Faults ◽  
Deep Penetration ◽  
Reverse Fault ◽  
Seismic Profiles

Abstract Along northeastern Mexico close to the Texas-Mexico border, the Burgos basin and its extension offshore was developed and deformed from the Paleocene up to Present time. This is a key triple junction between the sub meridian dextral transtensive coastal plain of the Gulf of Mexico extending far to the south in Mexico, the NE Corsair fault zone offshore and the sinistral Rio Bravo fault zone, a reactivated segment of the Texas lineament. Offshore NE Mexico, in the main study area covered by available seismic profiles, we have evidenced below the main well known gravitational décollement level (5 to 7 s twtt → 6 to 8 km) a Cenozoic deep-rooted deformation outlined by a N010° W trending deep-seated reverse fault zone and crustal folding down to the Moho (11 s twtt → ~ 20 km). Based on extensive offshore 2D industrial multi-channel seismic reflection surveys, deep exploration wells and gravimetric data, we focus our study on the deep crustal fabric and its effects on the gravitational tectonics in the upper sedimentary layers: submeridian crustal transtensional normal faults and open folding of the identified Mesozoic basement were interpreted as Cenozoic buckling of the crust during a major phase of oblique crustal extension. This deformation has probably enhanced gravity sliding along N030° growth-faults related to salt withdrawal and halokinesis in the offshore Burgos basin. We have tentatively made a link between this crustal deformation episode and the Neogene tectonic inversion of the Laramide foredeep basin of the Sierra Madre Oriental. The latter is still affected by crustal strike slip faulting associated with basaltic volcanism observed into the gulf coastal plain. This study favours a dominant crustal Cenozoic tectonic activity along the gulf margin without any clear evidence of Mesozoic tectonic reactivation. We propose that the large gravity collapse of the gulf margin was triggered by subsequent crustal deformation.

Neogene crustal shear zone along the western Gulf of Mexico margin and its implications for gravity sliding processes. Evidences from 2D and 3D multichannel seismic data

2008 ◽  
Vol 179 (2) ◽  
pp. 175-193 ◽  
Author(s):  
Charlotte Le Roy ◽  
Claude Rangin ◽  
Xavier Le Pichon ◽  
Hai Nguyen Thi Ngoc ◽  
Louis Andreani ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Shear Zone ◽  
Fault Zone ◽  
Crustal Deformation ◽  
Volcanic Belt ◽  
Reverse Fault ◽  
Fold Belt ◽  
Seismic Reflection Data ◽  
Late Neogene ◽  
2D And 3D

Abstract No significant crustal deformation was registered along the western Gulf of Mexico margin since the late Jurassic except the well known Cenozoic gravity tectonics. This is marked by a major extension across the platform and the upper continental slope compensated downslope by shortening across the Mexican Ridges fold belt. Based on extensive offshore 2D and 3D industrial multichannel seismic reflection data provided to us by PEMEX, we have evidenced significant Neogene deep-rooted deformation below the main décollement level (5 to 7 s-twtt) related to these gravitational processes. The main crustal deformation is outlined by a N170° trending deep-seated reverse fault zone, which flattens downwards near the Moho and merges upwards near the main Oligo-Miocene décollement level, close to the Neogene Mexican Ridges fold belt. This deep seated fabric is interpreted as the result of a dextral strike slip fault zone rather steep and linear into the north and connecting southwards to a N150° trending dextral wrench zone east of the Trans-Mexican volcanic belt. We consider that this Neogene transpressive dextral motion could have triggered gravity sliding along the Mexican Gulf margin. It could be located at the continent-ocean boundary and is probably linked to conjugate dextral slip related to the late Neogene N140° trending left lateral slip along the Veracruz shear zone active since the Late Miocene. We discuss whether this deep thrust wrench zone is related with the eastward migrating Laramide orogeny front dated Paleocene-Eocene.

scholarly journals Shallow seismic reflection imaging of the Inabanga–Clarin portion of the North Bohol Fault, Central Visayas, Philippines

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Romer Carlo T. Gacusan ◽  
Alfredo Mahar Francisco A. Lagmay
Keyword(s):  
Seismic Reflection ◽  
Risk Mitigation ◽  
High Surface ◽  
Normal Faults ◽  
Reverse Fault ◽  
Flower Structure ◽  
Seismic Profiles ◽  
The North ◽  
Shallow Seismic ◽  
Earthquake Hazard Assessment

Abstract On 15 October 2013, a magnitude 7.2 earthquake was generated from a previously unidentified fault in the island of Bohol. This fault was named the North Bohol Fault (NBF) by authorities. We investigated the geometry of the Inabanga–Clarin portion of the NBF using three high-resolution shallow seismic reflection profiles to image sections of the fault up to 150 m depth not seen in trenching and regional offshore seismic profiles. These seismic profiles are along the Calubian, Napo, and Caluwasan transects which run perpendicular to the N$$40^{\circ }$$ 40 ∘ E strike of the NBF. Reverse faults were identified in the Calubian and Napo profiles, whereas a positive flower structure was seen in the Caluwasan profile. Normal faults were also identified in the Caluwasan and Napo profiles. This study corroborates the observations in earlier trenching studies that measured the reverse fault dip angle and direction of the NBF at $$70^{\circ }$$ 70 ∘ SE. It also demonstrates that topographic flexures are the surface manifestation of steeply dipping faults. The downthrown block of the reverse faults in the Calubian profile defines a depression on the surface; the Napo seismic profile displacement of 3 m is consistent with the 3-m-high surface rupture in Barangay Anonang; and the flower structure in the Caluwasan profile is related to the pressure ridge and right lateral offset stream on the surface. Furthermore, the presence of normal faults as well as the other deformational features is consistent with the transpressional regime described in the literature, wherein the principal horizontal stress is oriented NW–SE. These findings complement earlier geomorphic and trenching investigations of the NBF and demonstrate the application of a tool to image the subsurface and characterize undescribed or hidden faults, which is necessary for earthquake hazard assessment and attendant risk mitigation and prevention planning.

scholarly journals Extensive Sills in the Continental Basement from Deep Seismic Reflection Profiling

Geosciences ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 449
Author(s):  
Larry D. Brown ◽  
Doyeon Kim
Keyword(s):  
Seismic Reflection ◽  
Country Rock ◽  
High Amplitude ◽  
Tectonic Activity ◽  
Seismic Profiles ◽  
Mafic Intrusions ◽  
Bright Spots ◽  
Crystalline Crust ◽  
Seismic Reflection Profiling ◽  
Fluid Magma

Crustal seismic reflection profiling has revealed the presence of extensive, coherent reflections with anomalously high amplitudes in the crystalline crust at a number of locations around the world. In areas of active tectonic activity, these seismic “bright spots” have often been interpreted as fluid magma at depth. The focus in this report is high-amplitude reflections that have been identified or inferred to mark interfaces between solid mafic intrusions and felsic to intermediate country rock. These “frozen sills” most commonly appear as thin, subhorizontal sheets at middle to upper crustal depths, several of which can be traced for tens to hundreds of kilometers. Their frequency among seismic profiles suggest that they may be more common than widely realized. These intrusions constrain crustal rheology at the time of their emplacement, represent a significant mode of transfer of mantle material and heat into the crust, and some may constitute fingerprints of distant mantle plumes. These sills may have played important roles in overlying basin evolution and ore deposition.

Structural Relations and Earthquake Hazards of the Crittenden County Fault Zone, Northeastern Arkansas

1992 ◽  
Vol 63 (3) ◽  
pp. 249-262 ◽  
Author(s):  
Anthony J. Crone
Keyword(s):  
Fault Zone ◽  
Crystalline Basement ◽  
Normal Faults ◽  
Reverse Fault ◽  
Seismic Zone ◽  
Earthquake Hazards ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Magnetic Basement ◽  
Structural Relations

Abstract A preliminary interpretation of about 135 km of seismic-reflection data provides new information on the structural relations between the the Crittenden County fault zone and the subjacent rift-bounding faults along the southeastern margin of the Reelfoot rift in the New Madrid seismic zone. On the reflection data, the rift boundary is marked by a 4- to 8-km-wide zone of incoherent reflected energy and disrupted reflectors in the lower part of the well-stratified, lower Paleozoic sedimentary rocks and in the underlying Precambrian crystalline basement. In places, the zone of disrupted reflectors extends into the upper part of the Paleozoic rocks, and, on some lines, disrupted reflectors and distinct faults are present in the Upper Cretaceous and Tertiary rocks of the Mississippi Embayment. The Crittenden County fault zone is interpreted as a northwest-dipping, high-angle reverse fault with an up-to-the-northwest throw, which is opposite to the net structural relief in the subjacent graben. The fault zone is at least 32 km long and coincides with the rift margin in southwestern Crittenden County, but to the northeast, it diverges away from the aeromagnetically defined margin of the rift by almost 4 km. Most faults in the Crittenden County fault zone are apparently ancient rift-bounding normal faults that were reactivated with a significant amount of reverse slip during the Mesozoic and Cenozoic. On the basis of its apparent connection with the rift-bounding faults, the evidence of its long history of recurrent movement, and its orientation with respect to the modern stress field, the Crittenden County fault zone might be considered to potentially generate major earthquakes. In contrast, the possibility that the Crittenden County fault zone could be a bending-moment fault argues against it being extremely hazardous. Precambrian crystalline basement interpreted on the profiles is commonly deeper than magnetic basement by as much as 2.5 km. This discrepancy between shallow magnetic basement and deeper crystalline basement could be explained by the presence of igneous intrusions in the Paleozoic strata immediately above Precambrian basement.

scholarly journals Structural analysis of S-wave seismics around an urban sinkhole: evidence of enhanced dissolution in a strike-slip fault zone

2017 ◽  
Vol 17 (12) ◽  
pp. 2335-2350 ◽  
Author(s):  
Sonja H. Wadas ◽  
David C. Tanner ◽  
Ulrich Polom ◽  
Charlotte M. Krawczyk
Keyword(s):  
Fault Zone ◽  
Fracture Network ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Normal Faults ◽  
S Wave ◽  
Seismic Profiles ◽  
Near Surface ◽  
Reflection Seismic ◽  
Enhanced Dissolution

Abstract. In November 2010, a large sinkhole opened up in the urban area of Schmalkalden, Germany. To determine the key factors which benefited the development of this collapse structure and therefore the dissolution, we carried out several shear-wave reflection-seismic profiles around the sinkhole. In the seismic sections we see evidence of the Mesozoic tectonic movement in the form of a NW–SE striking, dextral strike-slip fault, known as the Heßleser Fault, which faulted and fractured the subsurface below the town. The strike-slip faulting created a zone of small blocks ( < 100 m in size), around which steep-dipping normal faults, reverse faults and a dense fracture network serve as fluid pathways for the artesian-confined groundwater. The faults also acted as barriers for horizontal groundwater flow perpendicular to the fault planes. Instead groundwater flows along the faults which serve as conduits and forms cavities in the Permian deposits below ca. 60 m depth. Mass movements and the resulting cavities lead to the formation of sinkholes and dissolution-induced depressions. Since the processes are still ongoing, the occurrence of a new sinkhole cannot be ruled out. This case study demonstrates how S-wave seismics can characterize a sinkhole and, together with geological information, can be used to study the processes that result in sinkhole formation, such as a near-surface fault zone located in soluble rocks. The more complex the fault geometry and interaction between faults, the more prone an area is to sinkhole occurrence.

Seismic reflection profiling studies of a buried Precambrian rift beneath the Wabash Valley fault zone

Geophysics ◽  
1986 ◽  
Vol 51 (3) ◽  
pp. 640-660 ◽  
Author(s):  
John L. Sexton ◽  
L. W. Braile ◽  
W. J. Hinze ◽  
M. J. Campbell
Keyword(s):  
Seismic Reflection ◽  
Fault System ◽  
Normal Faults ◽  
Rift System ◽  
Seismic Profiles ◽  
Seismic Reflection Data ◽  
Wabash River ◽  
Gravity And Magnetic ◽  
Wabash Valley ◽  
Wabash Valley Fault System

Sixty‐eight kilometers of 12-fold seismic reflection data were collected in the Wabash River Valley of southwestern Indiana and southeastern Illinois to investigate the configuration of a basement structure inferred from regional gravity and magnetic anomaly data. The seismic profiles were also positioned to cross faults of the Wabash Valley fault system in a number of locations. Interpretation of the seismic reflection profiles and detailed gravity and magnetic profile data provides evidence for a series of northeasterly trending grabens in the basement. These grabens are filled with pre‐Mt. Simon layered rocks and are overlain by Paleozoic sedimentary rocks of the Illinois basin. Beneath the Wabash River near Grayville, Illinois, an interpreted graben (the Grayville graben) is approximately 15 km wide and contains about 3 km of fill. Individual boundary faults for the graben cut prominent reflectors within pre‐Mt. Simon rocks and display offsets of up to 500 m. The interpreted configuration of basement faults and thickness of pre‐Mt. Simon layered rocks provide evidence of a late Precambrian rift inferred to be one arm of the New Madrid rift complex. Post‐Pennsylvanian faulting of the Wabash Valley fault system is visible on the seismic reflection record sections as small offsets (less than 100 m) on steeply dipping normal faults. The downward projection of these faults intersects the older large‐offset faults within the pre‐Mt. Simon rocks suggesting that the Wabash Valley faults represent a post‐Pennsylvanian reactivation of the rift system.

scholarly journals Morphotectonics of the Padul-Nigüelas Fault Zone, southern Spain

2014 ◽  
Vol 56 (6) ◽  
Author(s):  
Jochen Hürtgen ◽  
Andreas Rudersdorf ◽  
Christoph Grützner ◽  
Klaus Reicherter
Keyword(s):  
Fault Zone ◽  
Sierra Nevada ◽  
Southern Spain ◽  
Tectonic Activity ◽  
Normal Faults ◽  
The South ◽  
Stream Length ◽  
Betic Cordilleras ◽  
Mountain Front ◽  
Granada Basin

The Padul-Nigüelas Fault Zone (PNFZ) is situated at the south-western mountain front of the Sierra Nevada (southern Spain) in the Internal Zone of the Betic Cordilleras and belongs to a NW-SE trending system of normal faults dipping SW. The PNFZ constitutes a major tectonic and lithological boundary in the Betics, and separates the metamorphic units of the Alpujárride Complex from Upper Tertiary to Quaternary deposits. Due to recent seismicity and several morphological and geological indicators, such as preserved fault scarps, triangular facets, deeply incised valleys and faults in the colluvial wedges, the PNFZ is suspected to be a tectonically active feature of the south-eastern Granada Basin. We performed morphotectonic GIS analyses based on digital elevation models (DEM, cell size: 10 m) to obtain tectonic activity classes for each outcropping segment of the PNFZ. We have determined the following geomorphic indices: mountain front sinuosity, stream-length gradient index, concavity index and valley floor width to height ratio. The results show a differentiation in the states of activity along the fault zone strike. The western and eastern segments of the PNFZ indicate a higher tectonic activity compared to the center of the fault zone. We discuss and critically examine the comparability and reproducibility of geomorphic analyses, concluding that careful interpretation is necessary, if no ground-truthing can be performed.

The evolution of the Malvern Lineament [abstract only]

1986 ◽  
Vol 317 (1539) ◽  
pp. 277-277 ◽  
Keyword(s):  
Seismic Reflection ◽  
Tectonic Activity ◽  
Normal Faults ◽  
Sedimentary Deposits ◽  
Westerly Direction ◽  
History Of ◽  
Early Palaeozoic ◽  
Western Side ◽  
Seismic Reflection Profiles ◽  
Uplift And Erosion

The geology of the Malvern Hills has been the subject of controversy since the 1850s. Many of the problems have now been resolved by using a combination of techniques including mapping, seismic-reflection profiling, deep drilling and geochronology. The Malvern Lineament is a major north-south trending crustal structure with a complex history of tectonic activity. In early Palaeozoic times thrusting on the Malvern axis caused uplift of the area to the east of the axis and some thickening of sedimentary deposits to the west. The importance of the Llandovery unconformity along the western side of the Malvern Hills is stressed. In late Carboniferous times there was major thrusting in a westerly direction, probably associated with dextral transpression, and considerable uplift and erosion of the area to the east of the Malverns. In Permian and Triassic times an extensional lithospheric stress field was initiated. This resulted in reactivation of the earlier thrusts as major normal faults down throwing to the east and with throws, locally, in excess of 2.5 km. These faults, which dip eastwards at between 35 and 50°, are detectable on seismic-reflection profiles to a depth of about 5 km and controlled the development of the Worcester Basin, inverting the site of an older ‘high’.

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