Fault-bounded Sedimentary Basins Research Articles

Postmagmatic Tectonic Evolution of the Outer Izu-Bonin Forearc Revealed by Sediment Basin Structure and Vein Microstructure Analysis: Implications for a 15 Ma Hiatus Between Pacific Plate Subduction Initiation and Forearc Extension.

International Ocean Discovery Program Expedition 352 recovered sedimentary‐volcaniclastic successions and extensional structures (faults and extensional veins) that allow the reconstruction of the Izu‐Bonin forearc tectonic evolution using a combination of shipboard core data, seismic reflection images, and calcite vein microstructure analysis. The oldest recorded biostratigraphic ages within fault‐bounded sedimentary basins (Late Eocene to Early Oligocene) imply a ~15 Ma hiatus between the formation of the igneous basement (52 to 50 Ma) and the onset of sedimentation. At the upslope sites (U1439 and U1442) extension led to the formation of asymmetric basins reflecting regional stretch of ~16–19% at strain rates of ~1.58 × 10−16 to 4.62 × 10−16 s−1. Downslope Site U1440 (closer to the trench) is characterized by a symmetric graben bounded by conjugate normal faults reflecting regional stretch of ~55% at strain rates of 4.40 × 10−16 to 1.43 × 10−15 s−1. Mean differential stresses are in the range of ~70–90 MPa. We infer that upper plate extension was triggered by incipient Pacific Plate rollback ~15 Ma after subduction initiation. Extension was accommodated by normal faulting with syntectonic sedimentation during Late Eocene to Early Oligocene times. Backarc extension was assisted by magmatism with related Shikoku and Parece‐Vela Basin spreading at ~25 Ma, so that parts of the arc and rear arc, and the West Philippine backarc Basin were dismembered from the forearc. This was followed by slow‐rift to postrift sedimentation during the transition from forearc to arc rifting to spreading within the Shikoku‐Parece‐Vela Basin system.

Crustal structure of the Gunsan Basin in the SE Yellow Sea from ocean bottom seismometer (OBS) data and its linkage to the South China Block

Two major tectonic units in NE Asia are the Sino-Korean (or North China) and South China Blocks that collided in the Permo-Triassic periods. The South China Block is suggested to extend eastward to the Korean Peninsula across the southern Yellow Sea. The Gunsan Basin is a well-defined, fault-bounded sedimentary basin in the SE Yellow Sea and is regarded as a structural link of the South China Block to the Korean Peninsula. We collected deep seismic sounding data recorded on ocean bottom seismometers to investigate how the crustal structure and nature of the South China Block vary in the Gunsan Basin toward the middle part of the Korean Peninsula. The main part of the Gunsan Basin is underlain by relatively thin (∼10 km thick) upper and much thicker (∼20 km thick) lower crustal layers, indicating a close affinity to the South China Block; whereas it shows distinction from the Korean Peninsula underlain by upper and lower crustal layers with equal (∼15 km) thickness. A change in crustal structure is recognized under the eastern margin of the Gunsan Basin toward the Korean Peninsula, that features a transition to the Korean Peninsula. The thick lower crustal layer in the Gunsan Basin appears to be inherited from the evolution of the South China Block including crustal shortening associated with the assembly of Rodinia in the Neoproterozoic before the collision between the Sino-Korean and South China Blocks.

Influence of pre-existing pervasive fabrics on fault patterns during orthogonal and oblique rifting: An experimental approach

Pervasive mechanical anisotropy (e.g. metamorphic foliation) in the pre-rift basement rocks often appears to control the orientation of new faults in natural rift systems, and thus tend to influence formation of fault-bounded sedimentary basins. However, the extent to which this influence works in nature has remained debatable, and contrasting ideas exist regarding the issue of structural inheritance in natural rifts like the East African Rift system. Earlier experimental works have investigated different kinematic aspects of faulting in simulated orthogonal and oblique rift systems, including the role of a crustal-scale pre-existing zone of weakness on continent-scale rifting. These experiments have tested the influence of discrete pre-existing weak zones (e.g. pre-existing faults or an ancient orogenic belt) on localization of subsequent rifting, but have not considered the control of pervasive fabric anisotropy (e.g. metamorphic foliation, etc.) in pre-rift basement rocks on the fault patterns during rifting. Here we present a series of simple, roughly scaled, analog model experiments where pervasive strength anisotropy in the basement was created by brushing plaster of Paris on a viscous (pitch) substratum. This way a transverse anisotropy of tensile strength was generated in the plaster of Paris layer due to thickness variation across the brush marks. The basement was overlain by a dry sand pack, simulating weak sedimentary rocks overlying a foliated crystalline basement. Orthogonal and oblique extension of the models at various angles, and with differently oriented strength anisotropy, exhibited the control of the anisotropy on the orientations of new faults in the sand layer. In general, anisotropy could significantly control the fault pattern only when it was at a high angle (>45°) with respect to the maximum instantaneous horizontal stretching direction (εH1), otherwise they largely disregarded the anisotropy and formed orthogonal to εH1. Faults never formed orthogonal to the displacement vector (D) in oblique rifting, unless the fault-controlling anisotropy was perpendicular to D. Faults strongly following the anisotropy were much longer than those not following that trend. Faults oblique to the anisotropy were short, segmented and tortuous in nature, and mainly grew by segment linkage. The experimental results support many field observations made in the East African Rift system, and are likely to be applicable to other rift systems like Gondwana basins of India, where field data on such structural inheritance are meager.

Growth, destruction and volcanic facies architecture of three volcanic centres in the Miocene Uşak–Güre basin, western Turkey: Subaqueous–subaerial volcanism in a lacustrine setting

Early to Mid-Miocene extension in western Anatolia, related to plate tectonic motions, resulted in the development of a number of normal fault-bounded sedimentary basins as well as different styles and compositions of volcanic activity. The Uşak and Güre basins accumulated a thick fluvio-lacustrine fill in which three distinct volcanic edifices (Elmadağ, İtecektepe and Beydağı) and their deposits can overlap with each other and with the sediments produced by the background sedimentation. In addition, complete facies architectures of small-volume (monogenetic) volcanoes have been recognised in association with the three large complex (polygenetic) volcanoes providing a complex mixed siliciclastic and volcaniclastic basin infill in the respective basins where volcanism took place.All three volcanic centres display a complex succession of effusive and explosive volcanisms and their reworked deposits, with abundant evidences of magma–water interaction such as peperites for non-explosive magma-water interaction with the lacustrine water-saturated sediment and standing water body in a large alkaline lake. During the constructive phase, proximal successions of pyroclastic flows, pyroclastic falls, and rarely surge deposits are associated with distally-emplaced debris flow deposits, sometimes of mixed volcanogenic and terrestrial origins, and are interbedded with lacustrine sediments of the Inay Group. All three volcanic centres then experienced a phase of volcano growth and degradation between 17 and 15Ma ago, most likely related to a combination of tectonic movements on NE–SW-trending basement faults, which triggered multiple flank collapses and volcanic debris avalanches (Elmadağ), and voluminous ignimbrite eruptions that triggered caldera formation (İtecektepe and Beydağı volcanic centres). Lacustrine conditions persisted during the destruction and post-destruction stages of the volcano's evolution, as evidenced by indications of magma–water interactions within the central collapse structures, which also contain uplifted basement metamorphic rocks now exhumed in their eroded cores.

Recurring extensional and strike-slip tectonics after the Neoproterozoic collisional events in the southern Mantiqueira province

In Eastern South America, a series of fault-bounded sedimentary basins that crop out from Southern Uruguay to Southeastern Brazil were formed after the main collisional deformation of the Brasiliano Orogeny and record the tectonic events that affected the region from the Middle Ediacaran onwards. We address the problem of discerning the basin-forming tectonics from the later deformational events through paleostress analysis of more than 600 fault-slip data, mainly from the Camaquã Basin (Southern Brazil), sorted by stratigraphic level and cross-cutting relationships of superposed striations, and integrated with available stratigraphic and geochronological data. Our results show that the Camaquã Basin was formed by at least two distinct extensional events, and that rapid paleostress changes took place in the region a few tens of million years after the major collision (c.a. 630 Ma), probably due to the interplay between local active extensional tectonics and the distal effects of the continued amalgamation of plates and terranes at the margins of the still-forming Gondwana Plate. Preliminary paleostress data from the Castro Basin and published data from the Itajaí Basin suggest that these events had a regional nature.

Total variation regularization for depth-to-basement estimate: Part 1 — Mathematical details and applications

We have developed an inversion approach that estimates the basement relief of a fault-bounded sedimentary basin. The sedimentary pack is approximated by a grid of 3D or 2D vertical prisms juxtaposed in the horizontal directions of a right-handed coordinate system. The prisms’ thicknesses represent the depths to the basement and are the parameters to be estimated from the gravity data. To obtain depth-to-basement estimates, we introduce the total variation (TV) regularization as a stabilizing function. This approach lets us estimate a nonsmooth basement relief because it does not penalize sharp features of the solution. We have deduced a compact matrix form of the gradient vector and the Hessian matrix of the approximation to the TV function that allows a regularized Gauss-Newton minimization approach. Because the Hessian matrix of the approximation to the TV function is ill conditioned, we have modified this Hessian matrix to improve its condition and to accelerate the convergence of the Gauss-Newton algorithm. Tests conducted with synthetic data show that the inversion method can delineate discontinuous basements presenting large slips or sequences of small-slip step faults. Tests on field data from the Almada Basin, Brazil, and from the San Jacinto Graben, California, U.S.A., confirm the potential of the method in detecting and locating in-depth normal faults in the basement relief of a sedimentary basin.

Late Neogene to Quaternary contractional structures in Crete (Greece)

Based on geological and tectonic investigations carried out along an N–S coast-to-coast transect across central Crete, southern Aegean (Greece), new meso- and macro-structural data mainly collected from Neogene–Quaternary deposits are presented and discussed. The occurrence of large-scale folds and thrusts together with diffuse minor contractional structures, as well as the overall geometry of the fault-bounded sedimentary basins document the persistence of a Tortonian–Early Pleistocene contractional regime, characterized by an NNW–SSE to NNE–SSW shortening direction and affecting the upper crust. This contractional event(s) was associated with the ongoing Hellenic subduction and caused the development of a southwards migrating out-of-sequence thrust system consisting of both reactivated inherited structures and new ones. The new data emphasize the importance and the extent of this contractional event intervening between the Early–Middle Miocene exhumation phase and the still active upper crustal extensional regime that was resumed in the island only during Pleistocene when the region was affected by diffuse normal faulting. While the contractional event was likely due to a stronger coupling along the overall subduction system, the onset of the new extensional stress conditions was probably related to a sudden southwards jump of the basal detachment along the lithospheric African subduction that caused a general stress release in the uppermost crust.

Structural evolution of the Laurentian margin revisited (southern Quebec Appalachians): Implications for the Salinian orogeny and successor basins

Research Article| January 01, 2002 Structural evolution of the Laurentian margin revisited (southern Quebec Appalachians): Implications for the Salinian orogeny and successor basins Alain Tremblay; Alain Tremblay 1INRS-Géoressources, Quebec Geoscience Centre, C.P. 7500, Quebec G1V 4C7, Canada Search for other works by this author on: GSW Google Scholar Sébastien Castonguay Sébastien Castonguay 2Geological Survey of Canada, Quebec Geoscience Centre, C.P. 7500, Quebec G1V 4C7, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Alain Tremblay 1INRS-Géoressources, Quebec Geoscience Centre, C.P. 7500, Quebec G1V 4C7, Canada Sébastien Castonguay 2Geological Survey of Canada, Quebec Geoscience Centre, C.P. 7500, Quebec G1V 4C7, Canada Publisher: Geological Society of America Received: 19 Mar 2001 Revision Received: 22 Aug 2001 Accepted: 12 Sep 2001 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2002) 30 (1): 79–82. https://doi.org/10.1130/0091-7613(2002)030<0079:SEOTLM>2.0.CO;2 Article history Received: 19 Mar 2001 Revision Received: 22 Aug 2001 Accepted: 12 Sep 2001 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Alain Tremblay, Sébastien Castonguay; Structural evolution of the Laurentian margin revisited (southern Quebec Appalachians): Implications for the Salinian orogeny and successor basins. Geology 2002;; 30 (1): 79–82. doi: https://doi.org/10.1130/0091-7613(2002)030<0079:SEOTLM>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The Laurentian margin of the Appalachians is divided into external and internal zones on the basis of metamorphic and structural contrasts. In the southern Quebec internal zone, Silurian to Early Devonian southeast-verging structures are superimposed on northwest-verging structures, whereas most of the external zone lacks such overprints. Regional backthrust faults define a major upper plate–lower plate boundary; the external-zone rocks are in the hanging wall, and internal-zone rocks are in the footwall. Metamorphic rocks with Silurian–Early Devonian 40Ar/39Ar ages (430–410 Ma) characterize the lower plate. To the east, the Saint-Joseph fault and the Baie Verte–Brompton line are southeast- dipping normal faults that crosscut the upper plate–lower plate boundary. Metamorphic rocks with Middle Ordovician 40Ar/39Ar ages (469–461 Ma) and rocks of the external zone both occur in the downthrown side of the Saint-Joseph fault and the Baie Verte–Brompton line. U-Pb and 40Ar/39Ar ages suggest that the northwest-verging structures are related to ophiolite obduction and crustal thickening during the Taconian orogeny (ca. 480–445 Ma), whereas the southeast-verging structures formed during Silurian–Early Devonian backthrusting and normal faulting. The revised structural interpretation has implications for the Salinian orogeny and involves (1) southeast-directed transport of the Taconian crustal wedge of the upper plate, followed by normal faulting and juxtaposition with the lower plate along the Saint-Joseph fault and the Baie Verte–Brompton line, and (2) the formation of fault-bounded sedimentary basins, such as the Connecticut Valley–Gaspé trough. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Going Away with the Flow?

CLIMATOLOGY The West Antarctic Ice Sheet (WAIS) contains enough ice that sea level would rise by approximately 5 meters if it were to melt completely in response to global warming. Even in the absence of large catastrophic collapse, the factors that control the transition from slow inland ice flow, dominated by internal deformation, to streaming flow, dominated by basal sliding, are important to understand in order to predict how the ice sheet will evolve and how much the sea level might rise. It has been suggested that a soft sedimentary bed may provide material to form a lubricating layer that allows ice streams to develop. Studinger et al. tested this proposal by using aerogeophysical data to estimate the distribution of marine subglacial sediments and fault-bounded sedimentary basins beneath the WAIS. They find that significant ice flow occurs exclusively in regions covered by subglacial sediments. The distribution of subglacial sediments therefore can provide a template for ice flow and has the potential to modulate the evolution of ice streams and the WAIS. — HJS Geophys. Res. Lett. 28 , 3493 (2001).

Basement geology and tectonic development of the greater New Zealand region: an interpretation from regional magnetic data

The basement geology of New Zealand is composed of early Palaeozoic terranes of the Western Province, that are separated from late Palaeozoic–Mesozoic Eastern Province terranes by a suite of Carboniferous–Cretaceous arc-related igneous rocks (Median Tectonic Zone, MTZ). The Stokes Magnetic Anomaly System (SMAS) is associated with MTZ rocks and volcanogenic basement terranes of the Eastern Province. Offshore, it can be traced north along the northern margin of the New Caledonia Basin, and correlative Eastern Province rocks are found in New Caledonia. It can also be traced south across the Great South Basin, until a significant ENE-trending tectonic boundary is encountered on the central Campbell Plateau. This boundary is defined by linear gravity and magnetic anomalies (Campbell Magnetic Anomaly System, CMAS), and narrow fault-bounded sedimentary basins. If the sources of CMAS anomalies are correlative with those of the SMAS, then magnetic data require a ∼400 km dextral offset of basement rocks by faults along the northern margin of the CMAS prior to 80 Ma. The geometry of correlative Western Province and MTZ rocks in Marie Byrd Land supports the hypothesis that CMAS anomalies are sourced by MTZ-correlative rocks. A NNE-trending boundary on the central Challenger Plateau marks a change from high amplitude magnetic anomalies to weakly magnetic basement, and appears to represent a fundamental change in crustal character. The western Challenger Plateau and Lord Howe Rise (south of 30°S) are characterised by high amplitude magnetic and gravity anomalies with a NW-trending fabric, but the source of magnetic anomalies is unresolved. The magnetic character, combined with Cretaceous reconstruction, supports basement rock correlations with the east Lachlan Fold Belt or New England Fold Belt in Australia, rather than Western Province rocks in New Zealand. The magnetic signature of marginal ocean crust around New Zealand also offers clues into the region's tectonic history. Negative magnetic anomalies adjacent to the Campbell Plateau and Lord Howe Rise, and in the New Caledonia Basin, suggest that seafloor formation started during chron 33r (79–83 Ma). A linear positive magnetic anomaly in the outer Bounty Trough may be anomaly 33, which was isolated by a ridge-jump, and is consistent with separation of the Bollons Seamount continental fragment by ocean crust. Alternatively, it may be anomaly 34 and represent the earliest ocean crust formed between New Zealand and Marie Byrd Land. Magnetic lineations in the southern South Fiji Basin suggest that at least one ridge–ridge–ridge triple junction was active during its opening, and imply that Cenozoic ocean crust is younger in the east. At the southern edge of the South Fiji Basin, there is a significant tectonic boundary, named here the van der Linden Fault. It can be traced for ∼500 km and may have been a leaky transform during basin formation.

Lithospheric extension northwest of the Central African Shear Zone in Sudan from potential field studies

The Central African Shear Zone (CASZ) is a 4000-km-long, NE-striking wrench fault system, along which motion occurred during the break-up of Gondwanaland, but its location in central Sudan was poorly defined. Prior to this study, it was thought that Mesozoic extension was restricted to Sudan south of the mapped and proposed location of the CASZ. We use nearly all gravity data from Sudan, including 1894 unpublished gravity points in eastern Sudan to (1) clarify the position of the CASZ in central and eastern Sudan and to (2) interpret anomalies northwest of the CASZ with similar trends and amplitudes as those basins known to occur southeast of the CASZ. Considering the dimensions of these gravity minima and existing geological, aeromagnetic, magneto-telluric, seismic and well data, we suggest that fault-bounded sedimentary basins lie north of the CASZ in central and eastern Sudan. We construct geological models of the Bara, Bagbag, Humar, Gilif and Abu Dulu rift basins to investigate the subsurface geometry of these previously undetected basins, constraining models with existing geological and geophysical data. The detrended gravity profiles can be fit by 40–60-km-wide basins bounded on one or both sides by normal fault systems, and with depths of 1.5–3.5 km. These patterns suggest that the CASZ in central and eastern Sudan is a broader zone of deformation than had previously been considered. The < 10 km cumulative Mesozoic extension within the African plate north of the CASZ implied by these studies, however, will not change significantly current plate models for the break-up of Africa and South America.

A new method for determining magnetization direction from gravity and magnetic anomalies: application to the deep structure of the Worcester Graben

The aeromagnetic field over the Worcester Graben, a major N-S-oriented, fault-bounded sedimentary basin, shows a large positive anomaly of 100 nT amplitude near the town of Tetbury. A new method for the determination of the magnetization direction of the causative body was employed that searches for the maximum correlation between the observed gravity anomaly and the pseudo-gravity anomaly computed for a range of orientations of the magnetization vector. The method suggests a vertical magnetization for the causative body of the Tetbury anomaly. A three-dimensional magnetic model of the body has the form of a cone, elongated N-S, whose base is at 6.0 km and upper surface at 3.1 km as indicated by power spectrum analysis of the anomaly. A two-dimensional model derived from the gravity field and constrained by the surface geology, borehole data and existing density measurements cannot simulate the observed anomaly over the centre of the graben. However, when the magnetic body is included in the gravity model, the fit is much improved. The western side of the body is probably imaged on a seismic reflection profile to the north. The body magnetic model of the body has the form of a cone, elongated N-S, whose base is at 6.0 km and upper surface at 3.1 km as indicated by power spectrum analysis of the anomaly. A two-dimensional

Possible evidence of a Precambrian continental collision in the Rio Pardo basin of eastern Brazil

Research Article| September 01, 1979 Possible evidence of a Precambrian continental collision in the Rio Pardo basin of eastern Brazil Augusto J. Pedreira Augusto J. Pedreira 1Companhia de Pesquisa de Recursos Minerais-CPRM Rua Barros Falcão, 21-40000 Salvador, Brazil Search for other works by this author on: GSW Google Scholar Author and Article Information Augusto J. Pedreira 1Companhia de Pesquisa de Recursos Minerais-CPRM Rua Barros Falcão, 21-40000 Salvador, Brazil Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1979) 7 (9): 445–448. https://doi.org/10.1130/0091-7613(1979)7<445:PEOAPC>2.0.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Augusto J. Pedreira; Possible evidence of a Precambrian continental collision in the Rio Pardo basin of eastern Brazil. Geology 1979;; 7 (9): 445–448. doi: https://doi.org/10.1130/0091-7613(1979)7<445:PEOAPC>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Some features in the basement rocks near the eastern coast of Brazil probably can be explained by plate-tectonics concepts. The area studied contains east-west-oriented diabase dikes, intrusive alkalic rocks, and miogeosynclinal sediments in a fault-bounded sedimentary basin now metamorphosed to greenschist facies, all affected by a northwest-southeast-trending shear zone. These features evolved chronologically in the sequence indicated, about 1,160 to 600 m.y. ago. The model devised by Sengör indicates that these features are possibly the product of a Precambrian collision between two continents with irregular margins. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.