Record of Late Mississippian tectonics in the new Percé Group (Viséan) of eastern Gaspésie, Quebec

2005 ◽  
Vol 42 (5) ◽  
pp. 815-832 ◽  
Author(s):  
Pierre Jutras ◽  
Gilbert Prichonnet
Keyword(s):  
Slip System ◽  
Marine Sediments ◽  
Strike Slip ◽  
Alluvial Fan ◽  
Normal Faulting ◽  
Broad Area ◽  
Tectonic Events ◽  
Upper Paleozoic ◽  
Maritimes Basin ◽  
Dextral Strike Slip

Viséan clastic units and structures at the northwest margin of the upper Paleozoic Maritimes Basin provide information on tectonic events that are only poorly recorded in more central parts of the basin. These continental units are time equivalent to marine sediments of the Windsor Group of Nova Scotia. They are herein assigned to the new Percé Group, which includes the La Coulée and Bonaventure formations, as well as a new unit, the Cap d'Espoir Formation. The latter unit unconformably underlies the Bonaventure Formation in a small but thick sub-basin of the Ristigouche Basin in eastern Quebec. It is characterized by a succession of sandstone and mudstone rhythmites that contrast with the coarse alluvial fan deposits of the overlying Bonaventure Formation. The Cap d'Espoir Formation was sourced from a broad area of subdued topography occupied by the Viséan La Coulée Formation and underlying units. Erosional remnants of the La Coulée Formation are unconformably overlain by the Bonaventure Formation in marginal parts of the Ristigouche Basin, whereas these units are separated by the Cap d'Espoir Formation in more central areas of the basin. The La Coulée and Cap d'Espoir formations underwent tilting and erosion during a normal faulting event that preceded deposition of the fault-controlled Bonaventure Formation. This series of events is interpreted to represent different steps in the reactivation of a pre-Carboniferous dextral strike-slip system in response to northwest–southeast compression during the Viséan in Gaspésie.

scholarly journals The Germania Land deformation zone and related structures, North-East Greenland

1994 ◽  
Vol 162 ◽  
pp. 113-127
Author(s):  
J.M Hull ◽  
J.A Gilotti
Keyword(s):  
Deformation Zone ◽  
Strike Slip ◽  
Low Grade ◽  
High Grade ◽  
Normal Faulting ◽  
East Greenland ◽  
North East ◽  
Parallel Movement ◽  
Land Deformation ◽  
Dextral Strike Slip

The Germania Land deformation zone in North-East Greenland consists of two subparallel, NW-striking strands of mylonites and cataclasites. The quasiplastic mylonites formed under low grade (biotite zone) conditions following high grade Caledonian metamorphism. Displacements on the Germania Land deformation zone and parallel zones at Danmarkshavn were predominantly dextral strike slip. Along with the similar, but sinistral, Storstrømmen shear zone, these zones record a late Caledonian phase of orogen-parallel movement. The Germania Land deformation zone is also the locus of Carboniferous normal faulting and basin development.

Mineralogy of the Au-Ag mineralization from the Finsterort and Anton vein system, Štiavnické vrchy Mts. (Slovakia)

2021 ◽  
Vol 29 (2) ◽  
pp. 255-269
Author(s):  
Jozef Vlasáč ◽  
Martin Chovan ◽  
Rastislav Vojtko ◽  
Peter Žitňan ◽  
Tomáš Mikuš
Keyword(s):  
Middle Miocene ◽  
Precious Metals ◽  
Central Zone ◽  
Strike Slip ◽  
Normal Faults ◽  
Normal Faulting ◽  
Vein System ◽  
Štiavnica Stratovolcano ◽  
Dextral Strike Slip ◽  
Strike Slip Movement

The Finsterort and Anton vein system is located in the central zone of the Middle Miocene Štiavnica Stratovolcano between Vyhne and Hodruša-Hámre villages. The vein system contains several partial veins and veinlets and has generally NNE - SSW strike with moderate to steep eastward dip. Kinematics of the veins is characterised by older dextral strike-slip movement replaced by younger normal faulting. The mineralization is associated with the normal faults and the veins contain interesting paragenesis of Au-Ag bearing minerals. Minerals of precious metals are represented by argentotetrahedrite-(Zn) and rozhdestvenskayaite-(Zn), Au-Ag alloys, members of polybasite-pearceite and pyrargyrite-proustite solid solutions, acanthite and uytenbogaardtite. Au-Ag mineralization is accompanied by older paragenesis comprising mainly pyrite, galena, sphalerite and chalcopyrite. Besides quartz, carbonates (calcite, siderite and dolomite) are the main gangue minerals.

Structural evolution of basement gneisses and Hadrynian cover, Bulldog Creek area, Rocky Mountains, British Columbia

1988 ◽  
Vol 25 (10) ◽  
pp. 1687-1702 ◽  
Author(s):  
Michael R. McDonough ◽  
Philip S. Simony
Keyword(s):  
British Columbia ◽  
Structural Evolution ◽  
Rocky Mountain ◽  
Strike Slip ◽  
Normal Faulting ◽  
The West ◽  
Kinematic Indicators ◽  
Thrust Sheets ◽  
Dextral Strike Slip ◽  
Southern Rocky Mountain

Two gneiss bodies are contained in thrust sheets on the west edge of the Rocky Mountain Main Ranges near Valemount, British Columbia. The Bulldog Gneiss comprises Aphebian or older paragneiss and amphibolitic gneiss intruded by Aphebian orthogneiss sheets. The Yellowjacket Gneiss is granodioritic orthogneiss of unknown age. Both gneiss bodies are basement highs with thin Hadrynian metasediment cover sequences. The cover sequences are assigned to the lower Miette Group and are correlated with Horsethief Creek Group.Internal shortening of gneiss thrust sheets is expressed by recumbent folding and stacking of thin thrust sheets of gneiss and cover. The Bulldog Gneiss and its cover were carried on the postmetamorphic Purcell Thrust. The Yellowjacket Gneiss and its cover were carried on the pre- to synmetamorphic Bear Foot Thrust. Northeast and northwest displacement is documented on the moderately southwest-dipping Bear Foot Thrust, and a dextral oblique-slip – thrust model is proposed to explain the duality of thrust and dextral strike-slip kinematic indicators in mylonite from the fault. An estimate of shortening in the fore-land suggests that basement thrust sheets were translated more than 200 km to the northeast.Correlation of gneisses and cover with the westerly adjacent Malton Gneiss and its cover precludes major dextral strike-slip motion on the Southern Rocky Mountain Trench (SRMT) during and after thrusting. The SRMT was the locus of post-thrusting and postmetamorphic, Eocene(?), brittle, west-side-down, normal faulting.

Seismotectonic Analysis of the 2019–2020 Puerto Rico Sequence: The Value of Absolute Earthquake Relocations in Improved Interpretations of Active Tectonics

2021 ◽  
Author(s):  
Copeland W. Cromwell ◽  
Kevin P. Furlong ◽  
Eric A. Bergman ◽  
Harley M. Benz ◽  
Will L. Yeck ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Moment Tensor ◽  
Active Tectonics ◽  
Strike Slip ◽  
Fault System ◽  
Normal Faulting ◽  
Rupture Area ◽  
Extensional Faulting ◽  
Dextral Strike Slip ◽  
East West

Abstract We present a new catalog of calibrated earthquake relocations from the 2019–2020 Puerto Rico earthquake sequence related to the 7 January 2020 Mw 6.4 earthquake that occurred offshore of southwest Puerto Rico at a depth of 15.9 km. Utilizing these relocated earthquakes and associated moment tensor solutions, we can delineate several distinct fault systems that were activated during the sequence and show that the Mw 6.4 mainshock may have resulted from positive changes in Coulomb stress from earlier events. Seismicity and mechanisms define (1) a west–southwest (∼260°) zone of seismicity comprised of largely sinistral strike-slip and oblique-slip earthquakes that mostly occurs later in the sequence and to the west of the mainshock, (2) an area of extensional faulting that includes the mainshock and occurs largely within the mainshock’s rupture area, and (3) an north–northeast (∼30°)-striking zone of seismicity, consisting primarily of dextral strike-slip events that occurs before and following the mainshock and generally above (shallower than) the normal-faulting events. These linear features intersect within the Mw 6.4 mainshock’s fault plane in southwest Puerto Rico. In addition, we show that earthquake relocations for M 4+ normal-faulting events, when traced along their fault planes, daylight along east–west-trending bathymetric features offshore of southwest Puerto Rico. Correlation of these normal-faulting events with bathymetric features suggests an active fault system that may be a contributor to previously uncharacterized seismic hazards in southwest Puerto Rico.

Deformation of soft sediments and evaporites in a tectonically active basin: Bay St. George sub-basin, Newfoundland, Canada

2021 ◽  
Vol 57 ◽  
pp. 275-304
Author(s):  
Morgan E. Snyder ◽  
John W. F. Waldron
Keyword(s):  
Hanging Wall ◽  
Normal Growth ◽  
Strike Slip ◽  
Late Paleozoic ◽  
Tectonic Structures ◽  
Tectonically Active ◽  
Maritimes Basin ◽  
Dextral Strike Slip ◽  
Slip Motion ◽  
Overlying Strata

The Bay St. George sub-basin of SW Newfoundland, part of the larger late Paleozoic Maritimes basin, formed under the influence of strike-slip faulting and the movement of evaporites. New stratigraphic correlations between Newfoundland and other late Paleozoic sub-basins illustrate the effects of both basement and salt movement. Coastal outcrops show complex combinations of synsedimentary, salt-related, and tectonic structures. Map relationships and dramatic thickness contrasts in the Tournaisian Anguille Group indicate that a large, concealed, NE–striking normal growth fault (Ship Cove fault) controlled sedimentation; the exposed Snakes Bight fault originated as a hanging-wall splay. Structures formed during, or soon after deposition include soft-sediment folds, boudins, clastic dykes, and millimetre-scale diapiric bulb structures, formed by overpressuring and liquidization of sediment. These suggest that the sub-basin was tectonically active throughout deposition. Evaporite-related deformation is recorded in the Visean Codroy Group and overlying strata. Comparisons between outcrop and subsurface suggests that significant amounts of evaporite were removed from exposed sections by halokinesis and solution. Complex outcrop relationships indicate salt welds, and suggest that units of the upper Codroy and overlying Barachois groups represent fills of minibasins that subsided into thick evaporites. Field relationships suggest tectonic inversion deposition related to E-W dextral strike slip motion that affected the entire Maritimes basin in the Serpukhovian, producing reverse-sense offsets and contractional folds. Many of the structures in the Bay St. George sub-basin, previously interpreted as post-depositional and purely tectonic, were formed by deformation of unlithified sediment and ductile evaporites during basin development.

scholarly journals Dextral strike‐slip and normal faulting during middle Miocene back‐arc extension and westward Anatolia extrusion in Central Greece

Tectonics ◽  
2021 ◽  
Author(s):  
Agathe Faucher ◽  
Frédéric Gueydan ◽  
Marc Jolivet ◽  
Manar Alsaif ◽  
Bernard Célérier
Keyword(s):  
Middle Miocene ◽  
Strike Slip ◽  
Normal Faulting ◽  
Central Greece ◽  
Back Arc ◽  
Dextral Strike Slip

The use of kink bands to constrain fault displacements: an example from the Bala Lineament, Wales

1992 ◽  
Vol 129 (5) ◽  
pp. 625-632 ◽  
Author(s):  
W. T. Pratt
Keyword(s):  
Fault Zone ◽  
Strike Slip ◽  
Normal Faulting ◽  
Qualitative Information ◽  
Close Link ◽  
Lower Carboniferous ◽  
Early Devonian ◽  
Kink Bands ◽  
Lower Palaeozoic ◽  
Dextral Strike Slip

AbstractThe Bala Lineament is a major NE-SW-striking fault zone that crosses the Lower Palaeozoic Welsh Basin. The southwest segment of it, the Tal-y-llyn Fault, mostly lies within a tract of Ordovician mudstones with few marker bands. Consequently, post-Caledonian (early Devonian) displacements are poorly understood. However, there is a close link between the distribution of kink bands and the fault zone. The kink bands provide information about the contemporary stress conditions and, in combination with slickensided fractures, give qualitative information about the various fault displacements. Matching of major folds across the fault suggests approximately 3–4 km of dextral strike-slip, probably of Lower Carboniferous age. A younger episode of normal faulting, perhaps related to Mesozoic extension, was accompanied by kink bands with more brittle characteristics.

scholarly journals Tectono-Sedimentary Evolution of the Cenozoic Basins in the Eastern External Betic Zone (SE Spain)

Geosciences ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 394
Author(s):  
Manuel Martín-Martín ◽  
Francesco Guerrera ◽  
Mario Tramontana
Keyword(s):  
Strike Slip ◽  
Alluvial Fan ◽  
Tectonic Activity ◽  
Time Interval ◽  
Se Spain ◽  
The Third ◽  
Sedimentary Evolution ◽  
Marine Sedimentation ◽  
Geodynamic Processes ◽  
Early Paleocene

Four main unconformities (1–4) were recognized in the sedimentary record of the Cenozoic basins of the eastern External Betic Zone (SE, Spain). They are located at different stratigraphic levels, as follows: (1) Cretaceous-Paleogene boundary, even if this unconformity was also recorded at the early Paleocene (Murcia sector) and early Eocene (Alicante sector), (2) Eocene-Oligocene boundary, quite synchronous, in the whole considered area, (3) early Burdigalian, quite synchronous (recognized in the Murcia sector) and (4) Middle Tortonian (recognized in Murcia and Alicante sectors). These unconformities correspond to stratigraphic gaps of different temporal extensions and with different controls (tectonic or eustatic), which allowed recognizing minor sedimentary cycles in the Paleocene–Miocene time span. The Cenozoic marine sedimentation started over the oldest unconformity (i.e., the principal one), above the Mesozoic marine deposits. Paleocene-Eocene sedimentation shows numerous tectofacies (such as: turbidites, slumps, olistostromes, mega-olistostromes and pillow-beds) interpreted as related to an early, blind and deep-seated tectonic activity, acting in the more internal subdomains of the External Betic Zone as a result of the geodynamic processes related to the evolution of the westernmost branch of the Tethys. The second unconformity resulted from an Oligocene to Aquitanian sedimentary evolution in the Murcia Sector from marine realms to continental environments. This last time interval is characterized as the previous one by a gentle tectonic activity. On the other hand, the Miocene sedimentation was totally controlled by the development of superficial thrusts and/or strike-slip faults zones, both related to the regional geodynamic evolutionary framework linked to the Mediterranean opening. These strike-slip faults zones created subsidence areas (pull-apart basin-type) and affected the sedimentation lying above the third unconformity. By contrast, the subsidence areas were bounded by structural highs affected by thrusts and folds. After the third unconformity, the Burdigalian-Serravallian sedimentation occurred mainly in shallow- to deep-water marine environments (Tap Fm). During the Late Miocene, after the fourth unconformity, the activation of the strike-slip faults zones caused a shallow marine environment sedimentation in the Murcia sector and a continental (lacustrine and fluvial) deposition in the Alicante sector represented the latter, resulting in alluvial fan deposits. Furthermore, the location of these fans changed over time according to the activation of faults responsible for the tectonic rising of Triassic salt deposits, which fed the fan themselves.

scholarly journals Kinematic partitioning in the Southern Andes (39° S–46° S) inferred from lineament analysis and reassessment of exhumation rates

2021 ◽  
Author(s):  
Paul Leon Göllner ◽  
Jan Oliver Eisermann ◽  
Catalina Balbis ◽  
Ivan A. Petrinovic ◽  
Ulrich Riller
Keyword(s):  
Fault Zone ◽  
Vertical Displacement ◽  
Strike Slip ◽  
Structural Studies ◽  
Southern Andes ◽  
Plate Convergence ◽  
Exhumation Rates ◽  
Lineament Analysis ◽  
Dextral Strike Slip ◽  
Data Call

AbstractThe Southern Andes are often viewed as a classic example for kinematic partitioning of oblique plate convergence into components of continental margin-parallel strike-slip and transverse shortening. In this regard, the Liquiñe-Ofqui Fault Zone, one of Earth’s most prominent intra-arc deformation zones, is believed to be the most important crustal discontinuity in the Southern Andes taking up margin-parallel dextral strike-slip. Recent structural studies, however, are at odds with this simple concept of kinematic partitioning, due to the presence of margin-oblique and a number of other margin-parallel intra-arc deformation zones. However, knowledge on the extent of such zones in the Southern Andes is still limited. Here, we document traces of prominent structural discontinuities (lineaments) from the Southern Andes between 39° S and 46° S. In combination with compiled low-temperature thermochronology data and interpolation of respective exhumation rates, we revisit the issue of kinematic partitioning in the Southern Andes. Exhumation rates are maximal in the central parts of the orogen and discontinuity traces, trending predominantly N–S, WNW–ESE and NE–SW, are distributed across the entire width of the orogen. Notably, discontinuities coincide spatially with large gradients in Neogene exhumation rates and separate crustal domains characterized by uniform exhumation. Collectively, these relationships point to significant components of vertical displacement on these discontinuities, in addition to horizontal displacements known from published structural studies. Our results agree with previously documented Neogene shortening in the Southern Andes and indicate orogen-scale transpression with maximal vertical extrusion of rocks in the center of the transpression zone. The lineament and thermochronology data call into question the traditional view of kinematic partitioning in the Southern Andes, in which deformation is focused on the Liquiñe-Ofqui Fault Zone.

Sign in / Sign up

Export Citation Format

Share Document