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.

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

Columbia River fault zone: southeastern margin of the Shuswap and Monashee complexes, southern British Columbia

1981 ◽  
Vol 18 (7) ◽  
pp. 1127-1145 ◽  
Author(s):  
Peter B. Read ◽  
Richard L. Brown
Keyword(s):  
Fault Zone ◽  
Hanging Wall ◽  
Columbia River ◽  
Glacial Sediments ◽  
Monashee Complex ◽  
Southeastern Margin ◽  
Minimum Age ◽  
History Of ◽  
Slip Displacement ◽  
Fault Scarps

The Columbia River fault zone extends for 250 km from south of Nakusp, through Revelstoke, to north of Bigmouth Creek. It is a composite fault zone, which dips 20–30° easterly and separates major tectonic elements. The structurally lowest element is the Monashee Complex, which includes the culminations of Pinnacle Peaks, Thor–Odin, and Frenchman Cap. At Hoskins Creek, the Monashee décollement splays westward from the fault zone and then runs southward along the western margin of the Monashee Complex. On the east side, the Selkirk allochthon is a composite of four tectonic slices. Its western part consists of Clachnacudainn, Goldstream, and French Creek slices forming the hanging wall of the Columbia River fault zone. The remainder of the allochthon forms the highest and largest Illecillewaet slice, which may be composite.The fault zone retains evidence of a long history of movement extending from the mid-Mesozoic to Eocene. Early deformation formed a mylonite zone up to 1 km wide in which rocks recrystallized under greenschist facies conditions. The displacement truncated major folds and metamorphic isograds that had developed in the Middle Jurassic. Orientation of slickensides, fiber growth, and strain features in the mylonite indicates normal, dip-slip displacement with the slices of the hanging wall moving eastward. South of Revelstoke, the Galena Bay stock, dated at 150 Ma, apparently intruded the zone and gives a minimum age for early displacement that must be in the Late Jurassic.Late displacement caused intense fracturing, folding of mylonite, and development of gouge zones. These features are well exposed at the Revelstoke damsite, continue north of Revelstoke, but diminish in importance southward. Late movement was again normal, dip-slip with the hanging wall moving eastward; it probably ended in the Eocene. No fault scarps or disrupted drainages have been observed, and at several localities glacial sediments lie undisturbed across the fault zone, indicating a lack of postglacial movement.Metamorphic zones, juxtaposed along the fault, imply a minimum dip-slip displacement of 15–25 km. Displacement in this range poses stratigraphic and metamorphic problems, which are alleviated if displacement is in excess of 80 km. The tectonic slices east of the Columbia River fault zone are part of an allochthonous cover that was transported at least tens of kilometres eastward over the Shuswap and Monashee complexes during the Late Jurassic.

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

A STRUCTURAL ANALYSIS OF THE WASHITA VALLEY FAULT IN THE SOUTHEAST ANADARKO BASIN

2020 ◽  
pp. 1-50 ◽  
Author(s):  
Molly Turko ◽  
Bryan Tapp
Keyword(s):  
Stress Field ◽  
Strike Slip ◽  
Anadarko Basin ◽  
Fault Movement ◽  
Lateral Strike Slip ◽  
Structural Inversion ◽  
Slip Displacement ◽  
Movement And Deformation ◽  
East End ◽  
East West

We propose that the Washita Valley Fault in the southeast Anadarko Basin originated when Precambrian-Cambrian pre-existing rift-related faults became reactivated as a rotational stress field reached a favorable orientation for strike-slip displacement. During the Early to Middle Pennsylvanian, contractional deformation dominated as a Precambrian-Cambrian failed rift underwent structural inversion along a northeast directed stress field. Structures that developed in the basin consisted primarily of thin-skinned fold-thrust structures resulting from slip along two main detachment levels. By the Late Pennsylvanian, stress rotated towards the east-northeast causing left-lateral strike-slip displacement along east-west oriented structures. During this time the Washita Valley Fault originated from an east-west oriented pre-existing basement fault. The Washita Valley Fault formed as a near-vertical segment cutting through the earlier fold-thrust structures. Movement was accompanied by oblique normal slip allowing grabens to develop that were subsequently filled with Virgilian age sediment. A left-step of the Washita Valley Fault allowed for a significant graben to develop near the east end of the study area resulting in a thick Virgilian age growth section validating the timing of fault movement. The Wichita Mountain Fault also underwent a component left-lateral strike-slip displacement during the Late Pennsylvanian highlighting its continuous movement and deformation history in a rotating stress field. While much of the published literature on the Washita Valley Fault is limited to the Arbuckle Uplift, our study documents its subsurface architecture, timing, and structural history in the southeast Anadarko Basin using a modern 3D seismic dataset in relation to evolving Pennsylvanian tectonics.

scholarly journals Haiti-Drill: an amphibious drilling project workshop

2020 ◽  
Vol 28 ◽  
pp. 49-62
Author(s):  
Chastity Aiken ◽  
Richard Wessels ◽  
Marie-Hélène Cormier ◽  
Frauke Klingelhoefer ◽  
Anne Battani ◽  
...  
Keyword(s):  
Fault Zone ◽  
Fault Zones ◽  
Strike Slip ◽  
Slip Rates ◽  
Significant Research ◽  
Research Questions ◽  
East West ◽  
Existing Data ◽  
Focus Point ◽  
Drilling Project

Abstract. The Haiti region – bounded by two strike-slip faults expressed both onshore and offshore – offers a unique opportunity for an amphibious drilling project. The east–west (EW)-striking, left lateral strike-slip Oriente–Septentrional fault zone and Enriquillo–Plantain Garden fault zone bounding Haiti have similar slip rates and also define the northern and southern boundaries of the Gonâve Microplate. However, it remains unclear how these fault systems terminate at the eastern boundary of that microplate. From a plate tectonic perspective, the Enriquillo–Plantain Garden fault zone can be expected to act as an inactive fracture zone bounding the Cayman spreading system, but, surprisingly, this fault has been quite active during the last 500 years. Overall, little is understood in terms of past and present seismic and tsunami hazards along the Oriente–Septentrional fault zone and Enriquillo–Plantain Garden fault zone, their relative ages, maturity, lithology, and evolution – not even the origin of fluids escaping through the crust is known. Given these unknowns, the Haiti-Drill workshop was held in May 2019 to further develop an amphibious drilling project in the Haiti region on the basis of preproposals submitted in 2015 and their reviews. The workshop aimed to complete the following four tasks: (1) identify significant research questions; (2) discuss potential drilling scenarios and sites; (3) identify data, analyses, additional experts, and surveys needed; and (4) produce timelines for developing a full proposal. Two key scientific goals have been set, namely to understand the nature of young fault zones and the evolution of transpressional boundaries. Given these goals, drilling targets were then rationalized, creating a focus point for research and/or survey needs prior to drilling. Our most recent efforts are to find collaborators, analyze existing data, and to obtain sources of funding for the survey work that is needed.

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.

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