bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proterozoic basement provinces of southern and southwestern Australia, and their correlation with Antarctica
Authors: Fitzsimons I. C. W. 
Published: April 2008

Abstract

Three Precambrian basement provinces extend from the southern coast of Australia into East Antarctica when reconstructed in a Gondwana configuration. These are, from east to west, the Mawson Craton, and the Albany-Fraser and Pinjarra Orogens. The Mawson Craton preserves evidence for tectonic activity from the late Archaean until the earliest Mesoproterozoic. It is exposed in the Gawler Craton of South Australia, the Terre Adélie and King George V Land coastline of East Antarctica, and the Miller Range of the central Transantarctic Mountains. It may form a significant part of the ice-covered East Antarctic Shield, although insufficient data are available to constrain its lateral extent. The Mawson Craton underwent late Palaeoproterozoic tectonism along its eastern margin (the Kimban Orogeny) and the occurrence of
c.
1700Ma eclogites in the Transantarctic Mountains implies that this was, in part, a collisional event, although elsewhere it was characterized by low
P/T
metamorphism. The western margin of the Mawson Craton collided with a continental fragment comprising the Nawa Domain of the Gawler Craton, the Coompana Block and the Nornalup Complex of Western Australia at
c.
1560Ma during the Kararan Orogeny. The western edge of the Nornalup Complex later collided with the Biranup and Fraser Complexes and Yilgarn Craton to form the Albany-Fraser Orogen during two stages of tectonism at
c.
1350–1260 and 1210–1140Ma. The Pinjarra Orogen truncates the western margin of the Yilgarn Craton and Albany-Fraser Orogen, and contains allochthonous 1100–1000Ma gneissic blocks transported along the craton margin during at least two stages of Neoproterozoic transcurrent movement. It divides East Gondwana into Australo-Antarctic and Indo-Antarctic domains, which are distinct continental fragments with different Proterozoic histories that were juxtaposed by oblique collision at 550–500Ma during the assembly of Gondwana. The path taken by the Pinjarra Orogen beneath the Antarctic ice sheet is unknown, but it is of similar width and length to the East African Orogen, and must have been a fundamental Neoproterozoic boundary of critical importance to supercontinent assembly and breakup.
Pan-African events in Prydz Bay, East Antarctica, and their implications for East Gondwana tectonics
Authors: Zhao Y. , Liu X. H. , Liu X. C. , Song B. 
Published: April 2008

Abstract

Decompression, anatexis and the clockwise granulite-grade
P-T
evolution of high-grade rocks of Prydz Bay reflect late collisional extension that occurred
c.
530 Ma in the Prydz Belt. Rapid cooling of the mid-crust high-grade terranes of the Prydz Belt was achieved during
c.
517-486 Ma by tectonically driven exhumation along dextral ductile shear zones in which late tectonic partialmelt bodies were emplaced. Instead of a model of polyphase metamorphism and deformation for the basement-and-cover sequences in Prydz Bay, we apply an accretionary one, i.e. an accretionary wedge with allochthonous blocks, to interpret the tectonic history in the Late Neoproterozoic of the Prydz Belt. SHRIMP U-Pb dates and Nd isotopic data available for both Prydz Bay and the Grove Mountains are used to explain amalgamation of the high-grade terranes in the Prydz Belt. This demonstrates that the assembly of the East Antarctic Craton was completed in the Pan-African event, and the East Antarctic Craton is a Pan-African-age collage rather than a keystone of East Gondwana during the Neoproterozoic.
Tracing tectonic deformation using the sedimentary record: an overview
Authors: McCann Tom , Saintot Aline 
Published: April 2008

AbstractTectonic activity, on a range of scales, is a fundamental control on sedimentary activity. The range of structural deformation within a region extends from the plate tectonic scale, governing, for example, rift initiation, to the basin scale, with the formation of basinbounding faults. Internal basin configuration is also strongly influenced by tectonic activity. However, the relationship between tectonic activity and sedimentation is a complex one, given the many additional factors which can also influence sedimentary activity, including erosion, sediment transport, source area lithology, groundwater chemistry, range of depositional environments, climate, eustasy, and the relative location of an area and its distality to marine influences. In this paper we provide a selective overview of the issues associated with the interlinked themes of tectonics and sedimentation, examining the main basin types forming in both extensional and compressional plate settings. We then review the various models of sedimentation in the selected basins, both on a local and a basinal scale. Finally, we look to the future — providing a series of possible research areas, almost exclusively multidisciplinary, which would help to improve existing models of interlinked sediment-tectonics systems.
Evaluation of controlling factors on facies distribution and evolution in an arid continental environment: an example from the Rotliegend of the NE German Basin
Authors: Rieke H. , McCann T. , Krawczyk C. M. , Negendank J. F. W. 
Published: April 2008

Abstract
About 3 km of core material from 14 wells together with additional data from several hundred wells across the NE German Basin (NEGB), have been investigated in order to reconstruct the facies architecture and the evolution of the Upper Rotliegend II. Special attention has also been given to the verification of various controlling factors and their influence on sedimentation in an arid continental environment. The facies architecture within the logged profiles comprises five main environments, namely braided plain, ephemeral stream floodplain, sand flat, mudflat and playa lake. The evolution can be subdivided into four distinct basin-wide correlatable periods — Parchim, Mirow, Dethlingen and Hannover formations — with each of them being characterized by a specific basin geometry and interplay of controlling factors. The deposition of the basal Parchim Formation largely took place within a tectonically created basin, whereas the facies evolution displayed an initial less-arid climatic period and later shift to an arid climate. The succeeding Mirow Formation marks the beginning of thermally induced basin subsidence. However, sedimentation itself clearly reflects a period in which the climate was relatively less arid. The overlying Dethlingen Formation was largely controlled by the increasing thermal subsidence of the basin, leading to broad extension towards the south and east. Internally, the strata can show the effects of climatic variability, depending on their position within the basin. The uppermost Hannover Formation was the product of ongoing basin subsidence, a reduction in sediment supply and an increasingly peneplaned topography. In summary, evolution of the Upper Rotliegend II within the NEGB reveals a variety of factors which have a significant influence on sedimentation, such as climate variations, the creation rate and amount of accommodation space, wind direction, sediment budget and source area lithology. An understanding of how these various factors interlink in controlling basin infill is of great significance in understanding the complex depositional history of arid continental successions.
Partitioning pre-, syn- and post-Variscan deformation in the Holy Cross Mountains, eastern Variscan foreland
Authors: Lamarche J. , Lewandowski M. , Mansy J.-L. , Szulczewski M. 
Published: April 2008

Abstract

In this study we demonstrate how a combined structural, sedimentological and palaeomagnetic approach provides a new perspective on the tectonic evolution of the Holy Cross Mountains. In the field, we performed a structural and sedimentological analysis of Palaeozoic rocks. Our analysis was complemented by a palaeomagnetic study and by the restoration of balanced cross sections in Palaeozoic and Mesozoic rocks. Different steps of deformation were restored for a
c.
350 Ma period. (1) The extensional tectonics of the Devonian basin was unravelled: the resulting normal fault system constituted the fundamental structural control for the later Variscan tectonic inversion and Alpine deformations. (2) The style of Variscan folding is characterized and quantified by way of a cross section across the Holy Cross Mountains. (3) The role of the reactivation of Variscan faults during the Permo-Triassic initiation of the Polish Basin was examined. (4) The localized Alpine compressive deformation was quantified and shown to contribute only to a minor degree to the present-day state of deformation in the Holy Cross Mountains. The Holy Cross Fault zone is the product of the interplay of changing transtensional and transpressional settings during the Variscan diastrophic cycle, with the final effect of the Variscan evolution being the flower-like structure of the Holy Cross Fault zone.
Oligocene-Early Miocene tectonic evolution of the northern Apennines (northwestern Italy) traced through provenance of piggy-back basin fill successions
Authors: Cibin U. , Di Giulio A. , Martelli L. 
Published: April 2008

Abstract
The provenance history of sediments deposited in the piggy-back basins of the Northern Apennines has been drawn by means of a petrographic study of nearly 200 sandstone samples collected over 250 km of the belt; it allows the evolution of the eroded part of the belt in Oligocene-Early Miocene times to be determined in detail, with special emphasis on the age of the exhumation and the onset of erosion of the high-pressure/low-temperature Pennine metamorphic units of the Ligurian Alps and Corsica that form the innermost part of the chain.
Five petrofacies were distinguished, representing three sources that were active separately (three ‘pure’ petrofacies) or together (two ‘mixed’ petrofacies). The resultion sandstone composition reflects the erosion of different source units, changing through time and space along the belt.
The stratigraphic distribution of petrofacies records a change in the main clastic source from Ligurian calcareous units to Penninic units. This change occurred over most of the study area, reflecting the complete exhumation of the Penninic metamorphic units within the innermost part of the belt. It occurred at different times along the chain, migrating from northwest to southeast from Late Rupelian to Aquitanian. This time shift is interpreted to be related to the obliquity of the Northern Apennines convergent system.
Silurian sedimentation in East Siberia: evidence for variations in the rate of tectonic subsidence occurring without any significant sea-level changes
Authors: Artyushkov E. V. , Chekhovich P. A. 
Published: April 2008

AbstractIt is widely accepted that major variations of sea-level have occurred in the Phanerozoic. Third-order cycles, 1–10 Ma long with amplitudes of 20–100 m, are of special interest for geochronology and petroleum geology. The amplitude of sea-level changes in the Silurian was estimated based on highly detailed data on the East Siberian Basin, which was 2×106km2in size. Fischer plots were compiled based on the thickness of 54 chronostratigraphic units — chronozones, each corresponding to a time intervalc.0.5 Ma long. The synchronicity of the chronozones ensures reliable comparison of the changes occurring with time in accommodation space in different regions. The subhorizontal Fischer plots derived for several regions indicate that sea-level changes were very small in the Silurian (<-5–10 m). A mathematical analysis of relative sea-level changes, which takes into account the finite rate of crustal subsidence and different possible forms of eustatic fluctuation, shows that from the observed structure of numerous Silurian successions in East Siberia, eustatic third-order sealevel changes could not have exceeded 6–20 m. In several regions of East Siberia, the rate of crustal subsidence varied as much as several hundred per cent at different times. These variations showed good similarity in form, but their amplitudes were different at different places in the basin. Most probably they were caused by variations in the rate of phase transformations in mafic rocks in the lower crust. Based on the example of the East Baltic, the absence of large-scale third-order cycles in eustatic changes of sea-level has been proven earlier for the Cambrian and earliest Ordovician. Probably, a similar situation was characteristic of many other epochs, when no large glaciations occurred, while many rapid changes of water depth in cratonic areas actually resulted from vertical crustal movements.
Fault and stress magnitude controls on variations in the orientation of
in situ
stress
Authors: Yale David P. 
Published: April 2008

Abstract
There has been a great deal of interest in mapping regional trends in stress orientation and their relationships to crustal deformation processes over the last quarter century. Less emphasis has been placed on explaining local variations in the stress field. However, it is variations in the local stress field which are most critical to characterizing hydrocarbon reservoirs. Fracture orientation, well stability, well orientation, and permeability anisotropy are all strongly affected by variations in the local stress field.
Using stress orientation data from a number of fields in different tectonic environments, we have tried to determine some of the tectonic and geological controls on variations in in situ stress orientation. We find that nearness to faults, fault structure, and magnitude of tectonic stress play primary roles in determining whether the regional stress field will be perturbed in a given reservoir and whether small-scale variations in the stress field can be expected.
We find that high tectonic stress environments (large horizontal differential stress) lead to a much more consistent local stress field than more tectonically quiescent areas. Faults can play a large role in rotating the local stress field. The smaller the difference between the maximum and minimum horizontal stress magnitude (i.e. lower tectonic stress), the larger a fault’s zone of influence is. Large-scale faulting with segmentation of the reservoir into discrete fault blocks can lead to significant stress orientation variations across the reservoir even in areas of large differential stress.
3D fracture network dynamics in reservoirs, faults and salt tectonic systems
Authors: Tuncay K. , Park A. , Payne D. , Ortoleva P. 
Published: April 2008

Abstract
A unique 3D computer simulator is used to predict natural fracture network characteristics in the subsurface. The model is based on the numerical solution of rock deformation processes coupled to the myriad of other basin reaction, transport and mechanical (RTM) processes. The model integrates seismic, well log and surface geological data to arrive at a quantitative picture of the distribution of fractures, stress, petroleum and porosity, grain size and other textural information.
An important component of the model is an incremental stress rheology that accounts for poroelasticity, non-linear viscosity with yield/faulting, pressure solution and fracturing. It couples mechanics to multi-phase flow and diagenesis (through their influence on effective stress and rock rheological properties, respectively). The model is fully 3D in terms of the full range of fracture orientations and the tensorial nature of stress, deformation and permeability. All rock properties (rheologic, multi-phase fluid transport, grain shape, etc.) are coevolved with the other variables. Examples illustrate the relative importance of various overpressuring mechanisms, lithology and flexure on the location and characteristics of a fracture network.
Difficulties and uncertainty in mathematical/numerical modelling of fluid flow in fractured media
Authors: Ewing Richard E. , Spagnuolo Anna M. 
Published: April 2008

Abstract
The ability to numerically model single-phase and multiphase flow of fluids in porous or fractured media is extremely important in developing an understanding of the complex phenomena governing the flow. The flow is complicated by the presence of heterogeneities in the reservoir at many different length scales by special flow features such as fractures or faults and by phenomena such as diffusion and dispersion. These effects must be effectively modelled by terms in coupled systems of non-linear partial differential equations which form the basis of the simulator. The simulator must be able to model both single and multiphase flows and the transition regimes between the two in unsaturated flow applications. A discussion of some of the aspects of modelling unsaturated and multiphase flows in the presence of heterogeneities and severe channelling is presented along with directions for future work. Simulators are severely hampered by the lack of knowledge of reservoir properties, heterogeneities, fracture dimension and orientation, and relevant length scales and other important mechanisms. Simulations can be performed either deterministically, to predict the outcome of a single realization of reservoir and flow properties, or via stochastic techniques to incorporate uncertainties of flow directly. Due to the extreme difficulties in using stochastic differential equation models for non-linear multiphase flows, we will concentrate on the potential of deterministic models. Recent developments have been made in homogenization, scaled averaging, and the use of the simulator as an experimental tool to develop methods to model the interrelations between localized and larger-scale media effects. Monte Carlo techniques using simulators with effective parameters can generate statistics for multiphase flow.
Fault development and interaction in distributed strike-slip shear zones: an experimental approach
Authors: Schreurs G. 
Published: April 2008

Abstract
Analogue model experiments using both brittle and viscous materials were performed to investigate the development and interaction of strike-slip faults in zones of distributed shear deformation. At low strain, bulk dextral shear deformation of an initial rectangular model is dominantly accommodated by left-stepping, en echelon strike-slip faults (Riedel shears, R) that form in response to the regional (bulk) stress field. Push-up zones form in the area of interaction between adjacent left-stepping Riedel shears. In cross sections, faults bounding push-up zones have an arcuate shape or merge at depth. Adjacent left-stepping R shears merge by sideways propagation or link by short synthetic shears that strike subparallel to the bulk shear direction. Coalescence of en echelon R shears results in major, through-going faults zones (master faults). Several parallel master faults develop due to the distributed nature of deformation. Spacing between master faults is related to the thickness of the brittle layers overlying the basal viscous layer. Master faults control to a large extent the subsequent fault pattern. With increasing strain, relatively short antithetic and synthetic faults develop mostly between old, but still active master faults. The orientation and evolution of the new faults indicate local modifications of the stress field. In experiments lacking lateral borders, closely spaced parallel antithetic faults (cross faults) define blocks that undergo clockwise rotation about a vertical axis with continuing deformation. Fault development and fault interaction at different stages of shear strain in our models show similarities with natural examples that have undergone distributed shear.
Recent strike-slip deformation of the northern Tien Shan
Authors: Buslov M. M. , Klerkx J. , Abdrakhmatov K. , Delvaux D. , Batalev V. Yu. , Kuchai O. A. , Dehandschutter B. , Muraliev A. 
Published: April 2008

Abstract
The paper presents a geodynamic interpretation of the deep structure and active tectonics of the northern Tien Shan, with particular emphasis on strike-slip motions, which produced a pull-apart in the centre of the Issyk-Kul basin. The study is based on a detailed interpretation of satellite imagery, fault plane solutions of earthquakes, seismic, and geodetic data.
Seismic and magnetotelluric studies show tectonic layering of the Tien Shan lithosphere, with several nearly horizontal viscoelastic layers and the lower layer underthrust northward in the northern Tien Shan. This active process may be responsible for the intricate present-day tectonic framework of the northern Tien Shan.
The recent tectonics of the northern Tien Shan inherits the earlier structure: The lens-shaped Issyk-Kul microcontinent comprising Precambrian-Palaeozoic metamorphic and magmatic rocks is surrounded by thick shear zones which have been involved in the activity over most of the Cenozoic. In the Quaternary the strain propagated as far as the central part of the Issyk-Kul basin.
Implications of late Pan-African shearing in western Dronning Maud Land, Antarctica
Authors: Perritt S. H. , Watkeys M. K. 
Published: April 2008

Abstract

The Mesoproterozoic cover rocks of the Archaean Grunehogna Province in western Dronning Maud Land, Antarctica, are gently folded and intensely fractured by a progressive ductile to brittle deformation event. The cause was dominantly NNW-SSE transpression related to a regionally extensive intracontinental sinistral strike-slip event at
c.
520 Ma. This reactivated the boundary between the Archaean Grunehogna Province and the high grade Mesoproterozic Maudheim Province, and resulted in the formation and deformation of the Cambrian Urfjell pull-apart basin. In a Gondwana refit, this strike-slip system can be linked to similar zones in southeast Africa which post-date the 750–650 Ma early Pan-African collisional events of that region. The NNW movement of the Maudheim Province along this strike-slip zone was responsible for the development of thrusts in the Lurio Belt of northern Mozambique. The driving force for this movement is considered to be related to the late Pan-African collisional events elsewhere in the growing supercontinent.
The Salina del Fraile pull-apart basin, northwest Argentina
Authors: Reijs J. , McClay K. 
Published: April 2008

Abstract
The Salina del Fraile in northwest Argentina is a Pliocene to Recent pull-apart basin developed at a releasing stepover along the NNE-SSW-trending El Fraile sinistral strike-slip fault. The basin is 35 km long and 12 km wide with a characteristic rhomboidal shape and is starved of synkinematic sediments thus providing unique 3D exposures. Prominent basin side-wall fault systems form scarps 700 m high and large tilted fault blocks form a terraced system along the southwest basin sidewall. A short-cut, basin-floor fault transects the pull-apart basin connecting the northwest strand of the El Fraile Fault to the southeast strand. An anticlinal positive flower structure in the northwest of the basin is a relict of early, segmented, fault growth typical of strike-slip fault evolution. Extension faults in the basin floor indicate a NE-SW intrabasinal extension direction during the Pliocene to Recent. The pull-apart basin accommodates an estimated 7.7 km of sinistral displacement along the El Fraile fault system. The morphology and fault architecture of the Salina del Fraile pull-apart can be directly compared to scaled sandbox models of strike-slip pull-apart basins. This first detailed analysis of the Salina del Fraile pull-apart basin provides a model for 3D architecture and evolution of similar pull-apart basins, and may serve as a template for the interpretation of other pull-apart systems.