Showing papers on "Pull apart basin published in 1984"

Deltaic sedimentation in the Lake Hazar pull‐apart basin, south‐eastern Turkey

Abstract: Lake Hazar lies within a small pull-apart basin along the East Anatolian Transform Fault in south-eastern Turkey Deltas are formed where streams debouch into the low-energy lacustrine environment The facies constituting the deltas include delta plain debris flow, braided stream, and marginal lacustrine deposits; delta front foreset and mouth bar deposits; prodelta and lacustrine deposits The facies are spatially restricted with sharp transitions Facies sequences and relationships indicate two distinct styles of deltaic sedimentation Fan deltas with a tripartite structure characteristic of Gilbert-type deltas comprise the marginal drainage system and form along the basin margins Mouth bar deltas develop where the axial drainage system of the basin debouches into the lake The distribution of the two deltaic types is thought to be a function of gradient and controlled by position relative to faults within the basin

Thin-Skinned Extension of Vienna Basin: ABSTRACT

Abstract: The Vienna basin is an area of middle Miocene (Karpatian-Badenian, 17.5-13.0 Ma) extension and contains up to 6 km (20,000 ft) of Miocene to Quaternary sedimentary rocks. This basin is partly superimposed on the north-vergent flysch belt of the outer West Carpathians and partly on more internal Carpathian nappes. The obvious rhombohedral shape of the Vienna basin, the left-stepping pattern of en echelon faults within the basin, and the southward migration of basin extension through time strongly suggest that this basin is a pull-apart feature formed during middle Miocene sinistral strike-slip faulting along a northeast-trending fault (or fault system). This interpretation is supported by geologic mapping in the Carpathians indicating several tens of kilometers of Tertiary sinistral displacement along a fault that trends northeast from the Vienna basin. This fault appears to have functioned mainly as a middle Miocene tear fault within the Carpathian nappes, separating the areas of active north-vergent thrusting east of the Vienna basin from areas west of the basin where thrusting had already been completed. Reflection seismic lines show that the autochthonous European plate basement continues beneath the allochthonous Carpathian nappes and beneath the Vienna basin, and that the European plate is not significantly disrupted by the normal faults that bound the basin. Thus both the normal faults that bound the basin and the associated strike-slip faults appear to merge into a gently southeast-dipping detachment horizon at depth. In this way extension of the Vienna basin appears to have been restricted mainly to shallow crustal levels ab ve that detachment horizon (i.e., restricted mainly to the allochthonous nappes of the Carpathians). Detailed analyses of subsidence and heat-flow data indicate that little or no heating of the lithosphere occurred during extension of the Vienna basin, and support the interpretation that extension was confined to shallow crustal levels. End_of_Article - Last_Page 523------------

Comparison of Tectonic Framework and Depositional Patterns of Hornelen Strike-Slip Basin in Norway and Ridge and Little Sulphur Creek Strike-Slip Basins of California: ABSTRACT

Abstract: Deposition in basins that develop adjacent to strike-slip faults can yield thick nonmarine sequences with similar facies and geometry. In this paper, we compare 3 basins of different age and size whose tectonic and depositional characteristics suggest a similar origin and history. The Hornelen basin developed during the Middle Devonian in western Norway. The basin is bounded on the north and south by east-west trending faults; the northern fault is considered to have been a zone of major right-slip movement. The basin is 60-70 km (38-43 mi) long, 15-25 km (9-16 mi) wide, and about 1,250 km2 (480 mi2) in areal extent; its 25,000 m (82,000 ft) of fill accumulated at an estimated rate of 2.5 m/1,000 yr (8 ft/1,000 yr). The Ridge basin developed during the Miocene and Pliocene between the right-lateral San Gabriel and San Andreas faults in southern California. The basin is 30-40 km (20-25 mi) long, 6-15 km (4-10 mi) wide, and about 200 km2 (80 mi2) in areal extent; its 7,000-11,000 m (23,000-36,000 ft) of fill accumulated at an estimated rate of about 3 m/1,000 yr (10 ft/1,000 yr). The 3 Little Sulphur Creek basins probably developed 4-2 m.y.B.P. along the east side of the right-lateral Maacama fault zone in northern California. These basins cumulatively are about 12 km (7 mi) long, 1.5-2 km (0.9-1.2 mi) wide, and about 15 km2 (6 mi2) in areal extent; their 5,000 m (16,000 ft) of fill accumulated at an estimated rate of about 2.5 m/1,000 yr (8 ft/1,000 yr). Coarse angular sedimentary breccia, which constitute a relatively small volume of the basin fill, was deposited in each of these basins along the active right-slip-fault margins as talus, landslide, and small but steep debris-flow-dominated alluvial fans. Along other margins of the basin, a much larger volume of the fill accumulated as larger streamflow-dominated alluvial fans, braided-stream, meandering-stream, fan-delta, and deltaic deposits. Lacustrine deposits that include turbidites and local chemical precipitates accumulated in the centers of the basins. The basin floors are generally tilted toward the active right-slip-fault margins so that the basin axes and the depocenters are subparallel to and shifted toward this margin. Sediment was transported toward the basin axis from s rrounding highlands and then longitudinally down the basin axis. The basin fills were syndepositionally folded and faulted, and postdepositionally folded into large plunging synclines. The basins lengthened over time and contain thicknesses of sediment that are comparable to or greater than their widths. End_of_Article - Last_Page 513------------

Paradox Basin: A Model Pull-Apart Basin of Pennsylvanian Age: ABSTRACT

Abstract: The Paradox basin of the east-central Colorado Plateau province is an elongate, roughly rhombic salt basin of Middle Pennsylvanian age. it is bounded on the northeast by the Uncompahgre-San Luis segments of the Ancestral Rockies. The writers have demonstrated previously that the End_Page 950------------------------------ basin sagged along basement rift zones by strong east-west extension during the Desmoinesian. The dominant zone of weakness was the northwest-trending Olympic-Wichita basement lineament that lies along the eastern margin of the Paradox salt basin and the southwestern edge of the Uncompahgre-San Luis uplifts. Less prominent northwest and northeast shear zones are ubiquitous, but are especially well developed in basement and Paleozoic rocks underlying the San Juan basin at the southeast termination of the Paradox basin. J. C. Crowell's classic model of a pull-apart basin along anastomosing transform fault zones is directly applicable to the Paradox basin, with the one exception that the Paradox is an intracratonic basin developed on continental crust. The primary zone of weakness, the Olympic-Wichita lineament, marks the abrupt eastern margin of the basin. The southwestern margin is less well defined along a broad zone of basement faults that trend northwesterly across the San Juan basin, through the southern margin of the salt basin, across the Monument upwarp at the anomalous Fish Creek structure and the Mille Crag Bend fracture zone, and on o the northwest through the Henry Mountains intrusives and the Fremont sag. The northwest termination is the expected irregular compressional (convergent) marg n at the Emery uplift (San Rafael swell), and the southeast limit of the basin is an irregular margin of normal faults and stretched attenuated floor (divergence) lying between the Hogback monocline and the House Creek fault. The complex intersections lying at the rhombic corners of the basin are in the San Juan Mountains on the southeast, the Defiance uplift on the southwest, the Fremont sag on the northwest, and the Oquirrh sag on the northeast. As the Paradox basin episodically deepened during the Middle Pennsylvanian by rejuvenation of basement faults, it was being filled contemporaneously with salt, which may have reached a thickness of 6,000-8,000 ft (1,800-2,400 m), and arkoses of 15,000-20,000 ft (4,600-6,100 m) thickness along the Uncompahgre front. A pull-apart of only about 5% of extension would account for a basin of this magnitude. By about mid-Desmoinesian time, the wrenching pull-apart was nearly completed. Folding caused by minor wrench movements formed shoaling conditions along the southwest shallow shelf of the basin where algal bioherms developed. Meanwhile, pull-apart stretching of the basin floor may have triggered salt flowage and diapirism in the eastern, deepest part of the basin. From the late Desmoines an through Permian, the basin filled with marine and nonmarine sediments as the wrench tectonism subsided. End_of_Article - Last_Page 951------------

Comparison of basin types in active and ancient strike-slip zones

Abstract: Hydrocarbon exploration in strike-slip zones requires awareness of several distinct basin types, traditionally defined on the basis of bounding fault geometry: pull-aparts (P), fault-wedge basins (W), fault-angle basins (A), fault-flank basins (F), and ramp valleys (R). We compare the characteristics and frequency of these basin types in an active (40 post-Eocene basins of the northern and southern Caribbean) and ancient (19 Late Devonian-Carboniferous basins of the northern Appalachians) strike-slip setting. Pull-apart basins, which lengthen and deepen at fault discontinuities with increased strike-slip offset, constitute the best studied and most numerous basin type. Other recognizable basin types are less numerous and often shorter lived than pull-aparts, and this may reflect: (1) their role as precursory structures prior to concentration of strike-slip displacement on a single fault; (2) their role as interference structures at random fault junctures; and (3) the unlikelihood of preservation because of thinner sedimentary fill. Several disrupted basins of complex or unknown origin (D) appear to have initiated as pull-aparts and subsequently to have been offset into halves or modified into compressional ramp valleys. Using observations from active basins, several geologic criteria for distinguishing compressional vs. extensional origin of reactivated ancient basins are discussed.

Strike-Slip Deformation, Basin Formation, and Sedimentation: A Summary: ABSTRACT

Abstract: Basins in which subsidence accompanied strike-slip deformation are known from the Proterozoic to Holocene. They occur in virtually all plate-tectonic settings (transform, convergent, and divergent plate margins, and plate interiors), and they are underlain in different places by crustal types ranging from continental to oceanic. In transform (wrench) systems, basins develop where fault strands splay, bend, or overstep in a divergent sense, and where plate motion is obliquely divergent to the strike of individual faults. Basins also develop between fault blocks rotating about vertical axes, and at some convergent splays, bends, and oversteps as a result of crustal loading. Basins formed by overall crustal extension (e.g., grabens) and by crustal loading (e.g., foredeeps) m y terminate against strike-slip faults. Basins associated with strike-slip deformation are filled with a wide range of sedimentary facies, deposited in nonmarine to deep marine environments. The principal controls on sedimentation are crustal type and thickness, plate-tectonic setting, amounts and rates of subsidence, relative sea level, topographic relief, and climate. Abrupt facies changes and discontinuities are relatively common. Subsidence rates are generally high, but there is significant variation within individual basins and from one basin to another. The type and degree of associated volcanic activity at any locality are related to tectonic setting and the amount of lithospheric extension. Heat-flow history is extremely variable, even within a single basin; consequently, the level of maturation of petroleum source ocks is notoriously difficult to predict in these types of basins. End_of_Article - Last_Page 462------------