scholarly journals Neotectonics in the foothills of the southernmost central Andes (37°-38°S): Evidence of strike-slip displacement along the Antiñir-Copahue fault zone

Tectonics ◽  
2004 ◽  
Vol 23 (5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Andrés Folguera ◽  
Víctor A. Ramos ◽  
Reginald L. Hermanns ◽  
José Naranjo
Keyword(s):  
Fault Zone ◽  
Central Andes ◽  
Strike Slip ◽  
Slip Displacement

Walker Creek fault zone, central Rocky Mountains, British Columbia-southern continuation of the Northern Rocky Mountain Trench fault zone

2000 ◽  
Vol 37 (9) ◽  
pp. 1259-1273 ◽  
Author(s):  
M E McMechan
Keyword(s):  
Fault Zone ◽  
Late Cretaceous ◽  
Lateral Displacement ◽  
Shear Bands ◽  
Rocky Mountain ◽  
Strike Slip ◽  
Fault System ◽  
Early Eocene ◽  
Fold And Thrust Belt ◽  
Slip Displacement

Walker Creek fault zone (WCFZ), well exposed in the western Rocky Mountains of central British Columbia near 54°, comprises a 2 km wide zone of variably deformed Neoproterozoic and Cambrian strata in fault-bounded slivers and lozenges. Extensional shear bands, subhorizontal extension lineations, slickensides, mesoscopic shear bands, and other minor structures developed within and immediately adjacent to the fault zone consistently indicate right-lateral displacement. Offset stratigraphic changes in correlative Neoproterozoic strata indicate at least 60 km of right-lateral displacement across the zone. WCFZ is the southern continuation of the Northern Rocky Mountain Trench (NRMT) fault zone. It shows a through going, moderate displacement, strike-slip fault system structurally links the NRMT and the north-central part of the Southern Rocky Mountain Trench. Strike-slip motion on the WCFZ occurred in the Late Cretaceous to Early Eocene at the same time as northeast-directed shortening in the fold-and-thrust belt. Thus, oblique convergence in the eastern part of the south-central Canadian Cordillera was apparently resolved into parallel northwest-striking zones of strike-slip and thrust faulting during the Late Cretaceous to Early Eocene. The change in the net Late Cretaceous to Early Eocene displacement direction for rocks in the Rocky Mountain trenches from north (56-54°N) to northeast (52-49°N) suggests that the disappearance of strike-slip displacement and increase in fold-and-thrust belt shortening in the eastern Cordillera between 56° and 49°N is largely the result of a north-south change in relative plate motion or strain partitioning across the Cordillera, rather than the southward transformation of right-lateral strike-slip displacement on the Tintina - NRMT fault system into compressional deformation.

Structure and formation stages of a fault zone in a geomedium layer in strike-slip displacement of the basement

2014 ◽  
Vol 17 (3) ◽  
pp. 204-215 ◽  
Author(s):  
Yu. P. Stefanov ◽  
R. A. Bakeev ◽  
Yu. L. Rebetsky ◽  
V. A. Kontorovich
Keyword(s):  
Fault Zone ◽  
Strike Slip ◽  
Slip Displacement

Brittle deformation in the Columbia River fault zone near Revelstoke, southeastern British Columbia

1984 ◽  
Vol 21 (5) ◽  
pp. 584-598 ◽  
Author(s):  
Larry S. Lane
Keyword(s):  
Fault Zone ◽  
Columbia River ◽  
Strike Slip ◽  
Fractured Zone ◽  
Displacement Vectors ◽  
Hydroelectric Dam ◽  
Slip Displacement ◽  
Shuswap Metamorphic Complex ◽  
Local Trend ◽  
East West

The brittle Columbia River fault zone forms part of the eastern margin of the Shuswap Metamorphic Complex, and for much of its 230 km length it coincides with the eastern exposure of the ductile Monashee décollement. The Eocene brittle fracturing and displacement are broadly parallel with, but cut and disrupt the middle Jurassic ductile mylonite zone. Excavations for a hydroelectric dam and a highway have facilitated a detailed analysis of fracture patterns at several localities along the fractured zone.Regionally, the brittle fault zone strikes 350° (locally 310–030°) and dips shallowly eastward. Over most of the studied part of the zone, the distributions of subsidiary fractures and displacement vectors demonstrate a normal dip-slip displacement consistent with subhorizontal east–west extension within the fractured zone, irrespective of the local trend of the zone. At Revelstoke damsite, where the zone trends 030° for 2 km, motion was towards the southeast, possibly indicating a localized clockwise rotation postdating dip-slip displacement.Fractures preserving both early dip-slip vectors and later strike-slip vectors demonstrate that minor north–south, strike-slip motion was superimposed on all parts of the zone, though no throughgoing strike-slip fault formed.In the damsite excavation, the fractured zone is largely confined to mylonites derived from footwall terrane. The Tertiary brittle offset was minor by comparison with the Jurassic ductile displacement.

Microearthquake study of the Elsinore fault zone, Southern California

1974 ◽  
Vol 64 (1) ◽  
pp. 187-203
Author(s):  
David Langenkam ◽  
Jim Combs
Keyword(s):  
Fault Zone ◽  
Southern California ◽  
Velocity Model ◽  
High Gain ◽  
Strike Slip ◽  
San Jacinto Fault ◽  
Crustal Velocity ◽  
Crustal Velocity Model ◽  
Slip Displacement ◽  
East West

Abstract Microearthquakes along the Elsinore fault zone, southern California, were monitored during the summer and fall of 1972. Four arrays of at least five portable, high-gain, seismographs were operated for about 12 days each from the vicinity of Corona to just north of the Mexican border. Over 5,000 hr of noisefree records were accumulated and analyzed. The recorded rates of seismic activity show a marked increase going from north to south along the fault— 0.5 events per day in the vicinity of Lake Elsinore to 3.7 events per day in the south near Monument Peak. Fifty-three events located, assuming a four-layer crustal-velocity model, show considerable scatter along the fault and are generally very shallow, averaging 3.3 km below sea level. A signal duration (D) versus magnitude (M) relationship was found: M = −1.9+2.0 log D. First motions of the located earthquakes indicate a complex pattern of faulting along the Elsinore fault zone. In comparison to the San Jacinto Fault to the east, the Elsinore Fault shows very little strike-slip displacement and is a seismically quiet area except for a localized area of east-west faulting in the far south near Vallecito Mountain.

The Ny Friesland Orogen, Spitsbergen

1992 ◽  
Vol 129 (6) ◽  
pp. 679-707 ◽  
Author(s):  
W. B. Harland ◽  
R. A. Scott ◽  
K. A. Auckland ◽  
I. Snape
Keyword(s):  
Fault Zone ◽  
Strike Slip ◽  
Central Province ◽  
The West ◽  
Eastern Province ◽  
Shallow Marine ◽  
Western Province ◽  
Slip Regime ◽  
Facies Metamorphism ◽  
Slip Displacement

AbstractThe Caledonides of Ny Friesland comprise the type Hecla Hoek sequence of Svalbard, a succession of late Proterozoic to Ordovician strata greater than 18 km thick. Three supergroups constitute the sequence: the Stubendorffbreen Supergroup (Riphean), the Lomfjorden Supergroup (late Riphean-Sturtian) and the Hinlopenstretet Supergroup (Varanger-mid-Ordovician). Basement elements have recently been identified within the Stubendorffbreen Supergroup, but their extent and significance is yet to be established. The Stubendorffbreen Supergroup records the deposition of sediments and volcanics (both acid and basic) in an unstable marine environment. In contrast, the Lomfjorden and Hinlopenstretet supergroups record sedimentation in a shallow-marine, periodically emergent, stable environment without volcanism. The Ny Friesland Orogen is divided into two subterranes by the Veteranen Line, a zone of attenuation along which sinistral strike-slip displacement has occurred. This line separates the strongly deformed Stubendorffbreen Supergroup rocks in the west from the less-intensely deformed Lomfjorden and Hinlopenstretet supergroup rocks in the east. Despite these contrasts and the obvious displacement, there is no evidence that a significant stratigraphie break occurs across it.All the supergroups were deformed and metamorphosed during the late Ordovician-Silurian Ny Friesland Orogeny. Early compressional deformation produced isoclinal folding and nappes in the Stubendorffbreen Supergroup rocks, accompanied by amphibolite faciès metamorphism; deformation in the Lomfjorden and Hinlopenstretet supergroups was less intense with open, upright folds and greenschist or subgreenschist facies metamorphism. Early compression was followed by a Silurian transpressive deformation that generated a pervasive lineation in the Stubendorffbreen Supergroup rocks. Transpressive deformation and the associated sinistral strike-slip was focused where strata were in a near-vertical attitude conducive to displacement. At a late stage in the orogeny, and probably still under a strike-slip regime, batholiths were emplaced into rocks east of the Veteranen Line.As a result of continued sinistral displacement (transpression, transcurrence and transtension) along the Billefjorden Fault Zone, Ny Friesland (part of the Eastern Province of Svalbard) finally docked against the Central Province during the late Devonian Svalbardian movements. At the same time, the Central Province docked against the Western Province. In total, hundreds of kilometres of Caledonian displacement along the Billefjorden Fault Zone brought the Eastern and Central provinces into their present positions. Pre-Carboniferous Svalbard is thus a composite terrane of at least three provinces, each comprising more than one minor terrane.

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.

40Ar/39Ar dating of strike-slip motion on the Tan–Lu fault zone, East China

2005 ◽  
Vol 27 (8) ◽  
pp. 1379-1398 ◽  
Author(s):  
Guang Zhu ◽  
Yongsheng Wang ◽  
Guosheng Liu ◽  
Manlan Niu ◽  
Chenglong Xie ◽  
...  
Keyword(s):  
Fault Zone ◽  
Strike Slip ◽  
East China ◽  
Slip Motion

Queen Charlotte fault zone: microearthquakes from a temporary array of land stations and ocean bottom seismographs

1981 ◽  
Vol 18 (4) ◽  
pp. 776-788 ◽  
Author(s):  
R. D. Hyndman ◽  
R. M. Ellis
Keyword(s):  
Fault Zone ◽  
Strike Slip ◽  
Ocean Bottom ◽  
Small Component ◽  
Queen Charlotte Islands ◽  
The North ◽  
Vertical Fault ◽  
Linear Sections ◽  
Ocean Bottom Seismographs ◽  
Steep Slopes

A temporary array of land and ocean bottom seismograph stations was used to accurately locate microearthquakes on the Queen Charlotte fault zone, which occurs along the continental margin of western Canada. The continental slope has two steep linear sections separated by a 25 km wide irregular terrace at a depth of 2 km. Eleven events were located with magnitudes from 0.5 to 2.0, 10 of them beneath the landward one of the two steep slopes, some 5 km off the coast of the southern Queen Charlotte Islands. No events were located beneath the seaward and deeper steep slope. The depths of seven of these events were constrained by the data to between 9 and 21 km with most near 20 km. The earthquake and other geophysical data are consistent with a near vertical fault zone having mainly strike-slip motion. A model including a small component of underthrusting in addition to strike-slip faulting is suggested to account for the some 15° difference between the relative motion of the North America and Pacific plates from plate tectonic models and the strike of the margin. One event was located about 50 km inland of the main active zone and probably occurred on the Sandspit fault. The rate of seismicity on the Queen Charlotte fault zone during the period of the survey was similar to that predicted by the recurrence relation for the region from the long-term earthquake record.

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