bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thrust and strike slip fault interaction along the Chaman transform zone, Pakistan
Authors: Lawrence R. D. , Yeats R. S. , Khan S. H. , Farah A. , DeJong K. A. 
Published: May 2008

Summary
The interaction between thrust and strike slip fault systems is well detailed in Pakistan where the Chaman transform zone connects the Makran and Himalayan convergence zones and contains an internal convergence zone in the Zhob district. The transform zone contains numerous strike slip faults of which the Chaman fault proper is the westernmost. We can demonstrate at least 200 km of left lateral displacement along the Chaman fault alone. In the Zhob belt N-S shortening by folds and a major thrust fault amounts to several dozen kilometres. The 400 km wide Makran convergence zone is now being shortened by E-W oriented folds, thrust faults, and reverse faults. As these faults in the Makran zone approach the transform zone, their traces bend to the N and motion on each of them becomes oblique, combining reverse and left lateral slip. They merge continuously with the strike slip faults of the Chaman transform zone. The Makran thrust system and the Chaman transform zone first became active in the late Oligocene or early Miocene. Later (Pliocene?), a component of left lateral shear occurred across the entire Makran Zone in association with the opening of the newly identified Haman-i-Mashkel fault trough S of the Chagai Hills and W of the Ras Koh. The total displacement and displacement rate across the Chaman transform zone varies in response to the rates of convergence in the plates E and W of the zone.
Active thrusting and the evolution of the Zagros fold belt
Authors: Jackson J. A. , Fitch T. J. , McKenzie D. P. 
Published: May 2008

Summary
Earthquake locations and fault-plane solutions reveal the spatial distribution and kinematics of strain release by faulting; information that is difficult to infer from geological evidence alone. In the Alpine-Himalayan belt, thrust faulting can be classified into one of three distinct types, each of which illustrates a particular aspect of continental deformation. Some thrusts are mechanically linked to strike-slip faults. Low angle thrusting is observed in regions where intermediate depth earthquakes and volcanism show that subduction is or was occurring. High angle reverse faulting at shallow depths is seen in the Zagros and it is suggested that this is the result of rejuvenation of old normal faults which stretched and thinned the basement of a Mesozoic continental margin.
Geometrical problems and implications of large scale over-thrusting in the Banda Arc -Australian margin collision zone
Authors: Audley-Charles M. G. 
Published: May 2008

Summary
Inversion of stratigraphical sequences, the presence of high grade metamorphic rocks sitting on serpentinite rafts bounded by unmetamorphosed sedimentary rocks, and zones of imbrication have been cited as evidence of large scale overthrusting in the Outer Banda Arc. Earthquake data reveal a Benioff zone implying intermediate depth and deep focus underthrusting beneath the Banda Arc but there is a paucity of shallow focus shocks with underthrusting mechanisms. Multichannel seismic reflection surfeys between the Outer Banda Arc and the Australian-New Guinea shelf have been interpreted as showing imbrication in the north wall of the Timor Trough and the S wall of the Seram Trough. Quaternary steep angled block faulting post-dates and thus obscures much of the thrust faulting in the Banda Arc.
Many geometrical problems arise in trying to interpret the structural history of this collision zone between Australia and the volcanic (Inner) Banda Arc. They include:- (1) the apparent absence of a subduction trench and accretionary arc-trench gap in the Banda Arc; (2) the location of the surface trace of the Benioff zone before collision; (3) the history of the Benioff zone after the Pliocene oceanic trench was destroyed; (4) the relationship of the developing fold and thrust belt to the pre-collision geometry of the Australia-New Guinea continental margin; (5) the apparent absence of the continental slope and rise in the northern Australia collision zone; (6) the relationship of the crystalline basement of the Outer Banda Arc to the cover rocks and (7) the tectonic significance of the apparent continuity of the stratigraphically and structurally very different Sunda and Banda Arcs.
Continent-arc collision resulted from the convergence of Australia and the Banda volcanic arc. The associated deformation, represented by the folding and local imbrication of the Australian continental rise sediments of the Outer Banda Arcs with the emplacement of overthrust exotic sheets, was accomplished in 2 Ma. It appears to have been caused by the failure of the Benioff zone to accommodate the thick sediment prism of Australian proximal continental rise. Geometrical considerations suggest that, as a consequence, the Benioff zone and most of the approximately 200 km wide arc-trench gap were overridden by the Australian lithospheric plate during the continued plate convergence of the last 3 Ma. An important conclusion is that the Banda Arc fold and thrust belt developed in proximal continental rise deposits at the foot of the Australian continental slope
Neogene thrust emplacement from a frontal arc in New Guinea
Authors: Milsom J. 
Published: May 2008

Summary
In northern New Guinea there is clear evidence that at some stage in the Neogene the northern margin of the Australian continent was in collision with a southwards facing island arc. There is still active volcanism along the whole length of this arc and a deep oceanic trench opposite the segment E of the collision zone. The Finisterre Range, a part of the former frontal arc and now part of northern New Guinea, lies up to 50 km S of its expected position with respect to the segments to E and W. Geological and geophysical evidence combine to suggest that this offset is not a deep seated feature, but is the result of movement on a very shallow thrust. Detachment of the thrust sheet from the remainder of the upper crust evidently took place along the line of weakness represented by the volcanic arc.
The mobile segment may have been the part of the frontal arc that first collided with the continental margin; the adjacent segments, which were probably, at the time of collision, opposite largely oceanic, and therefore much deeper, trenches, have not moved in this way.
Since its initial formation, the thrust sheet, or some parts of it, has evidently been involved in movements parallel to the strike of the arc.
The Cordilleran foreland thrust and fold belt in the southern Canadian Rocky Mountains
Authors: Price R. A. 
Published: May 2008

SummaryThe thick (∼40 km) slab of Hudsonian (>1750 Ma) continental crust that extends under western Canada from the Canadian Shield can be followed westward, on the basis of its distinctive magnetic anomalies, its influence on the Bouguer gravity values, the results of deep seismic refraction experiments, and the results of geomagnetic depth sounding of the deep electrical conductivity structure, to the Kootenay Arc. The Kootenay Arc is basically a W-facing monocline of crustal dimensions, across which the change in structural level involves an aggregate stratigraphic thickness of up to 20 km. It marks the western edge of the continental craton over which the displaced supracrustal rocks have been draped.Balanced structure sections of the thrust and fold belt, which take into consideration the deep crustal structure, as constrained by the geophysical data, show that: (i) in early Campanian time the continental crust that now lies beneath the western Rocky Mountains and the Purcell anticlinorium was covered with the platformal Palaeozoic to Upper Jurassic rocks and the exogeoclinal Mesozoic rocks that now form the northeasterly verging imbricate thrust slices of the eastern Rocky Mountains; (ii) the Cordilleran miogeocline developed outboard from the edge of the continental craton, on tectonically attenuated continental crust, or oceanic crust; and (iii) tectonic shortening of about 200 km in the supracrustal rocks in the Rocky Mountains must be balanced at a deeper level, W of the Kootenay Arc, by the shortening of the oceanic or attenuated continental crust.The net convergence between the Cordilleran magmatic arc and the autochthonous cover on the continental craton is a type of intra-plate subduction that was antithetic to the SW verging subduction zone marking the boundary of the North American Plate. The basement of the back-arc or marginal basin, in which the miogeocline formed, was consumed; but the adjoining continental margin was not. The foreland thrust and fold belt is a shallow subduction complex that was tectonically prograded over the margin of the continental craton, as the supracrustal cover scraped off the down-going slab was piled up against the overriding mass, and spread laterally eastward under its own weight.
The nature and significance of large ‘blind’ thrusts within the northern Rocky Mountains of Canada
Authors: Thompson R. I. 
Published: May 2008

Summary

The northern Canadian Rocky Mountains comprise a rugged, structurally complex Foothills subprovince of large amplitude box and chevron folds, and a structurally diverse Rocky Mountain subprovince in which large mappable thrusts are rare. The boundary between them is, in some regions, defined by the unfaulted E-dipping limbs of an
en echelon
sequence of large mountain-front anticlines. The lack of thrusts, especially along the mountain front, contrasts with the well exposed linearly continuous thrusts of the Front Ranges structural subprovince within the southern Rocky Mountains, and leads to the impression that little lateral displacement has occurred.

Where deep cross-cutting valley erosion combines with increased fold plunge, it is apparent that the frontal anticlines are, in reality, large allochthonous sheets displaced many kilometres eastward relative to the craton on flat thrusts that separate Ordovician shales from underlying Devonian and Mississippian shales. The faults can be traced, in some places, eastward to the mountain front where they cut abruptly through the thick hanging wall successions of carbonate rocks; however, they cannot be mapped further eastward into surface exposures because they terminate within a décollement zone of Devonian and Mississippian shales, where the displacement on them is transformed into disharmonic folds and tectonic thickening of overlying units.
The Devonian and Mississippian shale succession is interpreted as a fundamental décollement zone of regional extent that separates a lower structural level of thrustfaulted carbonate rocks from an upper structural level characterized by folded late Palaeozoic and Mesozoic units. The shortening represented by Foothills folds is interpreted to equal the amount of shortening on ‘blind’ thrusts beneath the western margin of the Foothills structural subprovince.
A structural reinterpretation across the Muskwa Anticlinorium using the blind thrust interpretation demonstrates that the mountain-front Tuchodi Anticline may represent a large allochthonous thrust sheet folded over a large step in the blind thrust on which it was transported.
The northern Rocky Moutains, narrower and less foreshortened than the southern Rocky Mountains, are interpreted as a thin-skinned tectonic regime similar to but orogenically less mature than the southern Rocky Mountains.
Metamorphic complex of SE Canadian Cordillera and relationship to foreland thrusting
Authors: Brown R. L. 
Published: May 2008

Summary
The Rocky Mountain miogeocline thickens westward into a basin that was established during the Proterozoic. The western margin of the basin is flanked by a platform that was developed upon Aphebian continental crust. These Aphebian rocks comprise the basement gneisses of the Shuswap Complex that have telescoped onto the cratonic margin of North America. The floor of the basin is assumed to have been transitional or oceanic crust that was subducted westward beneath the Aphebian continental crust of the Shuswap Complex.
Deformation of the platform and western margin of the basin was initiated in the Palaeozoic and culminated in the Jurassic. Development of easterly overturned folds in the basin and thrust faults along its eastern margin occurred during the final stages of ductile shortening of the basin. Thrust faults developed in the western margin of the miogeocline and deformation migrated eastward as the Shuswap Complex encroached upon the cratonic margin of the North American plate.
Eastward displacements of allochthonous cover rocks of the Shuswap Complex are post metamorphic events that are most likely interlocked with thrust faulting in the western margin of the Rocky Mountain miogeocline. Westward underthrusting of the basement of the miogeocline probably ceased by late Eocene and a regime of NE-SW extension was established. Most recent movements of allochthonous cover rocks and late doming of the metamorphic complex are related to this period of Tertiary extension.
Thrusts and nappes in the North American Appalachian Orogen
Authors: Hatcher R. D. 
Published: May 2008

Summary
The Appalachian Orogen in North America was subjected to three major deformational-thermal events: the Taconic (Ordovician-Silurian), Acadian (late Devonian), and Alleghanian (Permian). Each event involved large-scale horizontal transport of thrust-nappes ranging from tens to hundreds of kilometres in different parts of the orogen. Transport was dominantly westward although major Acadian-generated eastward transport occurred in southern New England.
There is a direct relationship between chronological proximity to a thermal peak and numbers of thrusts. Thrusts were produced during the Taconic and Acadian events which pre- and post-dated the thermal peak, as well as being synchronous with it. Transport of the Bay of Islands ophiolites and other large masses along the western margin of the orogen occurred before Taconic metamorphism, but probably only immediately before. Many large thrusts of the Appalachians were active during two or even three of the deformational-thermal events, and more than once within a single event. This is particularly true for the Blue-Ridge-Inner Piedmont mega-nappe, which involves at least 225 km of horizontal transport.
Compressional tectonics were probably the dominant process responsible for all thrusts in the Appalachians, except the Taconic klippes. The Alleghanian décollement Valley and Ridge thrusts are overridden by crystalline Alleghanian and older thrusts of the Blue Ridge in the southern Appalachians. The same mechanism must apply to the central Appalachians.
Thrusting and formation of crystalline thrust-nappes in the Appalachians and other mountain chains may be an adiabatic process which functions to dissipate much of the thermal energy produced during subduction (both A and B types) and collision events.
COCORP seismic reflection profiling across thrust faults
Authors: Brewer J. A. , Cook F. A. , Brown L. D. , Oliver J. E. , Kaufman S. , Albaugh D. S. 
Published: May 2008

Summary
It is very important to have good subsurface data in order to understand the nature and behaviour of thrust faults. Deep crustal seismic reflection profiling is the best technique currently available to make detailed subsurface studies of such important problems as the attitude and extent at depth of major faults, and hence deduce the mode of deformation and tectonic forces producing them. The Consortium for Continental Reflection Profiling (COCORP) is collecting large quantities of seismic reflection data from the deep crust and upper mantle in many parts of the U.S.A. Areas of major thrusting which have been profiled so far by COCORP include the Wind River Mountains in Wyoming and the Southern Appalachians of Georgia and Tennessee. Seismic profiles have been very successful in delineating a major thrust fault of moderate dip underlying the Wind River Mountains, thus demonstrating that compressional tectonics were dominant in their formation. In Georgia and Tennessee the seismic profiles demonstrate that the major tectonic feature of the Southern Appalachians is a relatively thin overthrust sheet, which may have moved at least 260 km. Deep crustal seismic reflection profiling thus appears to be an indispensable tool for the study of areas in which thrusting and nappe formation have occurred.
The Shimanto Belt of Japan: Cretaceous-lower Miocene active-margin sedimentation
Authors: Taira A. , Okada H. , Whitaker J. H. , Smith A. J. 
Published: May 2008

Summary
South-east of the two paired metamorphic belts of Kyushu, Shikoku and Honshu, and separated from them by the Chichibu and Sambosan belts and the Butsuzo Tectonic Line, lies a belt of mildly metamorphosed sedimentary rocks called the Shimanto Supergroup. Their area, extending from the Nansei Islands through Kyushu, Shikoku, Kii Peninsula, Akaishi and Kanto Mountains to the Boso Peninsula, is comparable in size with the combined Franciscan Formation and the Great Valley sequence in California. A Cretaceous lower group is flanked on the Pacific side by an upper group of Palaeogene to early Miocene age. The Shimanto sediments, mostly sandstones and mudstones, were deformed by cyclic subduction into open and isoclinal folds which close south-eastwards, and thrust slices which in places incorporate basaltic pillow lavas and radiolarian cherts.
Sandstones from Kyushu and Shikoku show marked changes of composition with stratigraphic position and the feldspar content can be used to distinguish Cretaceous from Tertiary sandstones. Data on sandstone petrography and palaeocurrents indicate that sediments of the Shimanto Supergroup were probably derived from the NW. Precambrian gneisses and older Mesozoic granitic rocks of the Korean Peninsula may have contributed sediments in Early Cretaceous times, when the Shimanto Terrane was located to the east of southern Korea. The unroofing of granites in the Inner Zone of SW Japan may also have contributed to the Cretaceous and later sedimentation. Quartz-rich, well-sorted sands in younger Shimanto sediments may have been recycled from older Shimanto formations.
The thick Shimanto sedimentary sequences were laid down in a variety of environments within a forearc basin on accretionary complex, trench-slope break, trench inner slope and trench settings; first in the Cretaceous and again, in a more southerly position, in the Palaeogene and early Miocene. In the shallower waters on the inner (arc) side of the Palaeogene forearc basin, coarsening- and thickening-upward deltaic sequences were deposited. In deeper water further offshore, submarine channel and fan complexes, base-of-slope slump deposits and red shales with cherts accumulated. Mélanges with basalts and slump olistostromes occupied the trench-slope break, while inner trench wall perched basins on accretionary basement were filled with coarsening-upward flysch, slump-olistostrome facies and mélanges with metabasalts: similar lithologies probably occupied a trench fill.
Sedimentation and deformation were controlled by intermittent cyclic subduction of the Kula Plate towards the north. Phases of tension and down-faulting, forming long, narrow intra-arc basins, alternated with those of compression. Comparable sedimentary environments are found today off SE Japan on the submarine terraces, trench-slope break, inner slope (including perched basins) and fill of the Nankai Trough.
Tectonics of some forearc fold belts in and around the arc-arc crossing area in central Japan
Authors: Ogawa Yujiro 
Published: May 2008

Summary
The zonal structure of the old Honshu arc in central Japan is deflected and cut by the colliding younger Izu-Bonin arc causing peculiar types of accretionary fold belts. The Shimanto Fold Belt (s.s.), made up of Cretaceous flysch and pre-flysch sediments, shows a collisional fold pattern: arcward vergence in the inner side and oceanward vergence on the outer side. The minor structures are also different, with shear folds on the inner side of the belt and lens folds on the outer side. Structures in the inner side grew by flattening and those in the outer side by simple shearing. The divergent development of structural characteristics is explained by the differences in geothermal gradient and stress fields across the belt. The Izu-Bonin arc has a forearc fold belt situated between the Honshu and Izu-Bonin arcs. The stratigraphical, palaeogeographical and structural history of the area shows that it developed in a strike-slip regime associated with the transform fault between the Eurasian and Philippine Sea plates.
Forearc geological structure of the Japanese Islands
Authors: Shiki Tsunemasa , Misawa Yoshibumi 
Published: May 2008

Summary
Under the forearc region off the Japanese Islands a conspicuous basal acoustic reflection plane can be traced at the surface of the acoustic basement from the oceanic plate into the bottom of the accretionary prism. Recent studies indicate this plane cannot be the upper boundary plane of the subducting oceanic plate, but must be the upper layer of the oceanic basaltic basement (or chert layer).
The tectonic activity of the Wadati-Benioff zone appears to be a thrust movement which cuts the boundary between the oceanic basement and the overlying sediments. Thrusts cut the basal reflector and extend into the accretionary prism. Large earthquakes which occur at intermediate and shallow depths under the continental shelf and slope are a direct manifestation of these thrust movements.
Thrust faulting also occurred in past geological time. Acidic and basic magma, possibly generated along the earthquake zone at intermediate depths, ascended along the thrust faults or associated normal faults. Intrusions occurred 15–16 Ma ago in the forearc region of Southwest Japan and 22 Ma ago in that of Northeast Japan; subsequently basins subsided landward of the intrusions. In some cases the forearc igneous rocks carried continental and oceanic crustal xenoliths. Good examples of such forearc igneous rocks, including xenoliths, occur in the Permian and Triassic structural belts of the Japanese Islands.
The model described here is specific to the forearc regions of the Japanese Islands. We envisage that different tectonic parameters such as convergence rate and sediment supply may engender different structural processes in other forearcs.