Prominent Lineaments Research Articles

Geophysical investigations in the Strath Halladale‐Altnabreac District (northeast Scotland) in relation to radioactive waste disposal

A series of geophysical studies have been carried out over the Strath Halladale Granite (around Altnabreac, northeast Scotland) as part of a multidisciplinary reasearch programme into the suitability of granitic rocks for radioactive waste disposal. Regional gravity and aeromagnetic data have been interpreted to investigate the structural setting of the Strath Halladale Granite. Ground magnetic and VLF surveys have been carried out to test their effectiveness in defining lithlogical variations, faults, and fracture zones beneath the ubiquitous cover of peat and moraine. Interpretations of the gravity and magnetic data suggest that the granite is a composite body approximately 3–4 km thick, comprising a dominant moderately magnetic variety with a subordinate (more evolved) nonmagnetic variety on the southeast margin. The intrusion apparently extends at shallow depth beneath Moine metasedimentary rocks east of the mapped contact at Altnabreac. The ground magnetic data indicate that the main body of (moderately magnetic) granite is interspersed with zones of less magnetic rock (Moine metasedimentary xenoliths and/or the more evolved variety of granite) and basic intrusions. Prominent lineaments in the magnetic field suggest dipping sheets of magnetically contrasting material, or faulted contacts. The VLF‐EM results indicate a number of anomalies which probably relate to fracture zones or lithological contacts.

Major dextral transcurrent displacements along the Northern Rocky Mountain Trench and related lineaments in north-central British Columbia

The Northern Rocky Mountain Trench and a number of other prominent lineaments, along and east of the eastern margin of the Intermontane Belt, mark faults along which dextral transcurrent movements have been dominant. Offsets of shelf to off-shelf facies boundaries in lower Paleozoic rocks indicate a cumulative displacement of at least 750 km, and probably >900 km, within the system of faults related to those in the Northern Rocky Mountain and the Tintina Trenches. Farther west, another system of faults appears to offset plutons and stratigraphic assemblages along the eastern margin of the Intermontane Belt by as much as 300 km. These faults, including the Kutcho and the Pinchi, connect in part with the Teslin Suture Zone in Yukon Territory and probably with the Fraser River-Straight Creek fault zone in southern British Columbia. Although dextral transcurrent faulting may have taken place between the Middle Jurassic and early Cenozoic, the most convincing evidence points to middle Cretaceous and particularly to early Cenozoic (Eocene?) displacements. The Eocene(?) movements were temporally related to plutonism, volcanism, lamprophyre dike emplacement, high heat flow, sedimentation in grabens, and rapid uplift of northwesterly trending elongate ranges. Climactic episodes of granite emplacement, particularly in and near the northern Omineca Crystalline Belt, at ∼100 m.y., 70 m.y., and 50 m.y. ago may have been facilitated by changes from dominantly compressional to dominantly transcurrent and related tensional strain.

Evidence against large-scale strike-slip separation of Paleozoic strata along the Richardson-Hess fault system, northern Canadian Cordillera

A review of geologic relationships across the Richardson-Hess fault system demonstrates that large-scale strike-slip separation did not occur among rocks younger than Proterozoic. Evidence against major lateral separation is: (1) Structural units of gently dipping Paleozoic strata, deformed during Columbian-Laramide orogenesis, show only 10 to 20 km (total) generally right-lateral separation across the fault system. (2) The only notable discontinuity across the fault system occurs along a prominent lineament at its south end. This discontinuity is part of a 200-km-long transition of thick Lower Cambrian quartzite and carbonate strata southwestward into argillite, and does not need to be explained by strike-slip faulting. (3) Lower Paleozoic paleogeography across the Richardson-Hess system features a complex arrangement of arches, basins, and troughs. All strata in and around these features are, at present, harmoniously juxtaposed.

Lineament Analysis near French Creek, Northwestern Pennsylvania: ABSTRACT

We are attempting to characterize the nature of linear topographic features in the vicinity of French Creek, northwestern Pennsylvania. Straight valleys that trend north to northwest and that are partially filled with glaciofluvial deposits distinguish prominent lineaments in Crawford, Venango, and Mercer Counties. The traces of these linear valleys are 1-15 mi (1.6-24 km) long and 10-4,000 ft (3-1,220 m) wide. The vertical extents of the lineaments are assumed to be proportional to their lengths. We assume that the topographic lineaments mark easily eroded zones coincident with fractures. The French Creek lineaments have been plotted on a Landsat photo, glacial map, regional map, and topographic maps. Subsurface structural and isopach maps may show facies changes or anomalous thickness across the lineaments. Geochemical surveys determine if there is any enhanced vertical migration of hydrocarbons along a lineament, and very low-frequency magnetic surveys would indicate any increase in groundwater concentration associated with the fracture zones. Well log data on initial production and breakdown pressures have been compared to lineament positions for possible correlations. End_of_Article - Last_Page 1925------------

Early Mesozoic Tectonics of Northern Gulf of Mexico Coastal Plain: ABSTRACT

Major events in the early Mesozoic development of the northern Gulf Coast region are related to corresponding stages in the opening of the central North Atlantic Ocean from its southern end, as interpreted from three prominent lineaments on aeromagnetic maps of the southeastern United States and its offshore region. The Brunswick magnetic anomaly, which marks the edge of continental crust in the Carolina trough, comes ashore in southern Georgia and follows the subsurface belt of Triassic rocks into southwestern Alabama. This belt continues into eastern Texas, occupying a rift system along which North America was then drawing away from South America. End_Page 1473------------------------------ East of the Brunswick anomaly (and therefore younger) is the East Coast magnetic anomaly, which is generally regarded as marking the eastern edge of the North American continent northward from Norfolk, Virginia. South of there the East Coast anomaly separates from the Brunswick anomaly and diverges from it to a distance of almost 50 mi (80 km) off South Carolina, as a result of restricted clockwise rotation and translation of central eastern North America around the bulge of northwestern Africa. Termination of the East Coast anomaly southward at the Blake Spur fracture zone suggests that spreading had started in the Blake Plateau basin south of it by the time the East Coast anomaly began to form in the Carolina trough to the north. The start of spreading in the Blake Plateau basin signaled the final separation from South America of the sliver of more or less continental material south of the Triassic rifts, and therefore the opening of the present Gulf of Mexico. All this was powered by a mantle plume located in the Blake Plateau basin, which was also responsible for continuing Jurassic compressional and right-lateral deformation in the southeastern states. Considering the rotations involved, the sequence of initial openings must have been: Gulf of Mexico, Blake Plateau basin, Carolina trough, and finally the northern central North Atlantic Ocean. The Triassic rift system localized the Interior salt basins of Jurassic age, whose southern rim is a continuous, gently curving trend of positive features that begins on the east with the Florida-Bahama Platform and continues west along the Wiggins arch to the Caldwell-Angelina flexure in southeastern Texas. This composite feature, which defines the northern margin of the Gulf of Mexico structural basin, functioned as an outer basement high that determined the seaward edge of the Early Cretaceous carbonate platform. The western limit of the Interior rift-basin system is a right-lateral wrench fault, which transferred the extensional movement south-southwest to a rift beneath the present Rio Grande Embayment. The edges of this rift are marked by the Chittim anticline on the north and by Mexico's Salado anticline farther south, which face each other with their steeper flanks, and converge as they approach the Sierra Madre Oriental to the northwest due to compression from the west that formed the Sierra. End_of_Article - Last_Page 1474------------

Morphotectonic analysis of the Hazara arc region of the Himalayas, north Pakistan and northwest India

In the Hazara arc region of northern Pakistan, some of the active basements structures buried below a thick, detached sedimentary layer are inferred from the distribution of lineaments and the drainage patterns, as viewed in Landsat satellite imagery and from river profiles.A prominent set of NW-trending lineaments seen on satellite imagery, coincides approximately with the southwest or updip side of the Indus—Kohistan seismic zone (IKSZ) —the most active basement structure of the region, even though this structure is buried beneath and decoupled from a 12 km thick sedimentary layer. The IKSZ has been interpreted as an extension of the Himalayan Basement Thrust, and is also associated with a prominent topographic “step”.Knickpoints on major rivers in the region lie on or north of the IKSZ. All Indus River tributaries, examined north of the IKSZ, show prominent knickpoints, while two tributaries draining south of the IKSZ have no knickpoints. These results suggest ongoing uplift above and north of the IKSZ, and are consistent with the tectonic model obtained from the seismic data.Another prominent lineament set is detected along the north—south section of the Indus River. This set is probably related to the Indus River horst—anticline and associated reentrant.One of the two highest lineament concentrations occurs at the intersection between the NW-trending IKSZ lineament and the N-trending Indus River lineament. The other is along the west bank of the Indus Valley, 25 km north of Tarbela Dam.A topographic ridge (Swabi—Nowshera ridge) appears to be forming along the west side of the Indus River, in the Peshawar Basin. The rising ridge is ponding the Kabul River upstream of Nowshera, where the drainage is braided.

Comments on Structure Within Wichita Mountains Crustal Block: ABSTRACT

Work in preparation for a new map of the Wichita Mountains has led to revisions of the surface structure within the exposed igneous rocks. As the presumed faulting pattern will have bearing on the development of regional tectonic models, it is important to document clearly whether major structural discontinuities exist inside this crustal block. Fault distributions within the main igneous outcrops in the eastern Wichitas have been shown on the Oklahoma state geologic map and carried forward in Oklahoma Geol. Survey Hydrologic Atlas 6. These faults can be grouped into two categories based on stratigraphy: those separating rocks of the same stratigraphic unit, and those separating rocks of different stratigraphic units. Field work over the period of 1977 to the present now hows that all those previously accepted faults which allow contact of different igneous lithologies are actually intrusive contacts. Accordingly, such faults do not exist. No unequivocal major faults (i.e., separations of tens to hundreds of meters) have been identified in the igneous rocks although prominent lineaments do exist. The work described above plus new published stratigraphic information on the igneous sequence leads to several speculative ideas on regional deformation associated with the Wichita arch. These ideas follow somewhat the reasoning advanced by Ham, Denison, and Merritt, but with modifications as required by new data. (a) The integrity of the main Wichita Mountains horst block results from its underlying gabbroic substrate (Raggedy Mountain gabbro group) rather than the covering, thin Wichita granites, or Carlton rhyolite. (b) Intrusion of the Roosevelt gabbros as small plutons into the Glen Mountains layered complex marks the beginning of the Wichita Mountains block as a structural unit. This timing is not yet well-dated but is clearly pre-rhyolite and pre-granite in age. (c) Few faults will be found in areas underlain by much gabbro. For example, faults bounding the south side of the Anadarko basin may indicate the most northerly extent of gabbro. Basement beneath the Anadarko basin should have little gabbro. End_of_Article - Last_Page 1498------------

Seasat Radar Image of San Andreas Fault, California

On a Seasat radar image (23.5-cm wavelength) of the Durmid Hills in southern California, the San Andreas fault is expressed as a prominent southeast-trending tonal lineament that is bright on the southwest side and dark on the northeast side. Field investigation established that the bright signature corresponds to outcrops of the Borrego Formation, which weathers to a rough surface. The dark signature corresponds to the Lake Cahuilla sand and silt deposits which are smooth at the wavelength of the Seasat radar. These signatures and field characteristics agree with calculations of the smooth and rough radar criteria. On Landsat and Skylab images of the Durmid Hills, the Borrego and Lake Cahuilla surfaces have similar bright tones and the San Andreas fault is not detectable On a side-looking airborne radar image (0.86-cm wavelength), both the Borrego and Lake Cahuilla surfaces appear rough, which results in bright signatures on both sides of the San Andreas fault. Because of this lack of roughness contrast, the fault cannot be distinguished on the aircraft image acquired at a short radar wavelength. The wavelength of the Seasat radar system is well suited for mapping Durmid Hills geologic features that are obscure on the other remote sensing images evaluated in this report.

Structural Geology of Aconcagua Province and Its Relationship to the Central Valley Graben, Chile

Research Article| June 01, 1965 Structural Geology of Aconcagua Province and Its Relationship to the Central Valley Graben, Chile W. D CARTER; W. D CARTER U. S. Geological Survey, Washington, D. C. Search for other works by this author on: GSW Google Scholar LUIS AGUIRRE LE B LUIS AGUIRRE LE B Institute de Investigacions Geológicas, Santiago, Chile Search for other works by this author on: GSW Google Scholar GSA Bulletin (1965) 76 (6): 651–664. https://doi.org/10.1130/0016-7606(1965)76[651:SGOAPA]2.0.CO;2 Article history received: 23 Nov 1964 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation W. D CARTER, LUIS AGUIRRE LE B; Structural Geology of Aconcagua Province and Its Relationship to the Central Valley Graben, Chile. GSA Bulletin 1965;; 76 (6): 651–664. doi: https://doi.org/10.1130/0016-7606(1965)76[651:SGOAPA]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 SocietyGSA Bulletin Search Advanced Search Abstract Aconcagua Province is herein divided into three major structural provinces which, for the sake of simplicity, are named the Coastal Cordillera, Central Valley graben, and Andean Cordillera structural provinces to correspond to the three geomorphic provinces recognized farther south.The coastal structural province includes the Coastal Cordillera which is underlain mainly by layered sedimentary and effusive rocks that strike north and dip homoclinally to the east, range from Triassic to Late Cretaceous in age, and are intruded by Cretaceous granodioritic and dioritic rocks. Igneous and metamorphic rocks largely of Paleozoic age comprise the western coastal margin, Along the eastern edge of the province is the Los Angeles fault zone, a wide, poorly defined band of semiparallel, arcuate faults which show downward displacement to the east and which appear to have resulted mainly from intrusion and uplift on the west. The Coastal Cordillera, therefore, may be considered a large horst with an intrusive granodiorite core.The Central Valley graben is bounded on the west by the Los Angeles fault zone and on the east by the Pocuro fault zone. Between these two fault zones is an area 20–30 km wide in which volcanic rocks of Late Cretaceous age are flat lying to gently folded and block faulted. In places, pipelike stocks of andesitic to dioritic igneous rock intrude the area. The Pocuro fault zone is a prominent lineament that marks the eastern limit of the Central Valley at Santiago and has been traced northward for 150 km. It may, however, have a mappable length of more than 1200 km. Vertical displacement downward to the west has been measured near Los Andes to be at least 2000 m. Consequently, this fault zone may rank among the major faults of the world.The Andean structural province is subdivided into the Las Ollas and Juncal subprovinces. The Las Ollas is a mountainous front range that lies east of the Pocuro fault and extends eastward for about 25 km. Upper Cretaceous volcanic strata are gently warped into broad, open, north-trending folds, with local sharp flexures and faulted mainly by normal faults. The eastern part of the subprovince is cut by a narrow belt of Tertiary plutonic rocks, some of which are associated with porphyry copper deposits. The Juncal structural subprovince extends eastward into Argentina. It is typified by close, overturned folding, vertical bedding, and thrust faulting. In general, structural deformation increases in intensity from west to east, with imbricate overthrusting to the east in Argentina.Present evidence indicates that major graben formation began during early Tertiary (pre-Miocene) time as a result of tensional stress developed by strain release of earlier compressional forces that folded the Andes. Post-Miocene uplift of the central Andean region renewed tensional stress and opened deep-seated, north-striking fractures and reinitiated volcanism. Most of the active volcanos of Chile may be aligned along such fractures. 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.

Introduction to Tectonics of Rocky Mountains: ABSTRACT

The Rocky Mountain system extends from the Liard River, B. C., to Santa Fe, New Mexico, and is the dominant geological feature within the seven-state Rocky Mountain section. Five tectonic divisions based on the present structural position of the Precambrian crystalline basement exist within the system and the adjacent eastern area. The divisions are: Canadian shield; thinly covered shield; area of locally exposed basement; area of deeply buried basement; and the area where the basement is no longer recognizable. End_Page 785------------------------------ Precambrian rocks exposed over large areas of Canada collectively form the Canadian shield. The exposed basement is bounded in Alberta and Saskatchewan by overlying sediments. The surface upon which the overlying sedimentary rocks were deposited is warped into a major syncline the steeper limb of which lies in or near the disturbed belt of Alberta and Montana and along the Rocky Mountain front. In this syncline the basement is covered by a relatively thin veneer of sediments except for local areas such as the Williston basin. Petroleum accumulation in the area of thin sedimentary cover is controlled more by stratigraphic than by structural factors. The area of local exposure of the Precambrian basement includes the Southern Rockies, the Wyoming basin, and part of the Middle Rocky Mountain province. Prior to deformation the basement was thinly covered by sediments. Anticlinal mountain ranges and deep local intermontane basins characterize the region. The site of deformation was localized by the Pennsylvanian structural history. Petroleum accumulation is largely controlled by geologic structure. The Precambrian basement was deeply depressed beneath the troughs existent in central Utah, western Wyoming, eastern Idaho, western Alberta, and eastern British Columbia during late Precambrian and early Paleozoic time. Deformation of the troughs created the overthrust belt characterized by repetition of the sedimentary sequence in overthrust fault plates. Absence of Precambrian basement rocks in the thrust plates suggests that faulting is localized in the sedimentary sequence. Accumulation of petroleum have been negligible in this division. The Precambrian basement complex is no longer recognizable in the areas of batholithic intrusion in Idaho, Montana, and British Columbia. The development of granite and granite gneiss in the Idaho batholith, age 100 MY, modified the pre-existing rocks, and substituted a new floor for subsequent geologic history. Lineaments of primary significance are superimposed across the tectonic divisions. The lineaments have complex geologic histories in which transverse movement was probably important. The prominent lineaments are: Rocky Mountain trench, Montana lineament, Wyoming lineament, and the Walker lineament, all of which separate regions of differing geology. Volcanically derived materials of Cenozoic age are widely spread across the Rocky Mountain system, and reflect igneous activity of great magnitude. Extensive tectonic adjustment took place by means of normal and reverse faulting both during and subsequent to the deposition of the volcanic products. The extent and magnitude of the late Cenozoic faulting are as yet incompletely understood. Critical discrimination should be made between fault systems of different ages. End_of_Article - Last_Page 786------------