bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asymmetric lithosphere as the cause of rifting and magmatism in the Permo-Carboniferous Oslo Graben
Authors: Pascal Christophe , Cloetingh Sierd A. P. L. , Davies Gareth R. 
Published: April 2008

Abstract
Compared to other Permo-Carboniferous rift basins of NW Europe, the Oslo Graben has two distinct characteristics. First, it initiated inside cold and stable Precambrian lithosphere, whereas most Permo-Carboniferous basins developed in weaker Phanerozoic lithosphere, and second, it is characterized by large volumes of magmatic rocks despite relatively little extension. Seismic reflection surveys show that the crust thickens from southern Norway to southern Sweden, the most significant Moho deepening occurring from the Oslo Region eastwards. Deep seismic studies also suggest that the base of the lithosphere deepens markedly eastwards from the Oslo Region. Such a long-wavelength lithospheric geometry cannot be explained by the Permian or post-Permian evolution of the area, hence the Oslo Graben appears to have evolved at the transition between two lithospheric domains with contrasting thickness. Numerical thermo-mechanical modelling is applied to test if this transitional position can influence the dynamics of rifting. Different models with varying lithosphere thickness contrast are considered. Model results show that a crust and lithosphere thickness contrast comparable to the Oslo Region can explain rifting and focusing of magmatism in a narrow zone with minor thinning of the crust. Models also account for the major characteristics of the Oslo Graben in terms of location and strain distributions in the crust.
Magmatism of the late Variscan intermontane Saar-Nahe Basin (Germany): a review
Authors: von Seckendorff Volker , Arz Christoph , Lorenz Volker 
Published: April 2008

Abstract

The Saar-Nahe Basin is a late Variscan intermontane basin that developed on the site of an earlier island arc, the Mid-German Crystalline Rise. Within the
c.
6500m-thick continental sedimentary fill of the basin, a large variety of igneous rocks was emplaced over a period of
c.
4 Ma from 296 to 293 Ma as high-level intrusions and lava flows, extrusive domes, diatremes and pyroclastic deposits, ranging in composition from basalt and basaltic andesite to rhyodacite, rhyolite and trachyte. Composite intrusive-extrusive complexes consist of andesite, rhyodacite and alkali feldspar trachyte with up to 10 wt% K
2
O. The geochemical characteristics of the most primitive mafic magmas indicate a slightly enriched upper mantle source modified by subduction-related fluids. Nd-Sr-O isotope data indicate that crustal contamination was important in the petrogenesis of the more differentiated magmas.
Microstructural evolution in a mylonitic quartz simple shear zone: the significant roles of dauphine twinning and misorientation
Authors: Lloyd Geoffrey E. 
Published: April 2008

Abstract

SEM/EBSD-based orientation and misorientation analyses are described for a lower amphibolite facies simple shear zone (Torridon, NW Scotland). It is shown that as well as conventional crystal-slip processes (i.e. basal-

a

, prism-

a

, rhomb-

a

and negative second order rhomb-

a

slip), dauphine twinning also plays a role in both microstructural and petrofabric evolution. Twinning assists in the initial grain size comminution processes, including dynamic recrystallization, from originally coarse wall rock grains to a typical mylonitic microstructure in the centre of the shear zone. Subsequently, twinning helps to accommodate high shear strains in the mylonite whilst maintaining a stable microstructure and constant ‘single crystal’ petrofabric. The role of dauphine twinning appears to be to allow efficient switching between relatively ‘soft’ and relatively ‘hard’ slip directions that possibly exploit a distinction between negative and positive crystal forms. Misorientation analysis emphasizes the relationships between crystal-slip systems and grain boundary network, including dauphine twin planes, and suggests that the mylonitic microstructure contains preferred orientations of both tilt and twist boundaries that help to explain shear zone microstructural evolution and stability.
Strain removal within the Hercynian Shear Belt of Central Brittany (western France): methodology and tectonic implications
Authors: Gumiaux C. , Brun J. P. , Gapais D. 
Published: April 2008

Abstract
Central Brittany comprises a major shear belt formed during the Hercynian Orogeny. In this paper, we present a model for the restoration of the belt, based on an exhaustive compilation of available structural data. The model uses a geostatistical analysis of cleavage orientation data. The analysis shows that the eastern part of Central Brittany has been deformed by bulk dextral strike-slip, a feature that validates previous structural interpretations. It also provides explanations for: the strain patterns observed within and around the restored domain; the nature of domain boundaries and of associated kinematics; and the occurrence of local superimposed deformations.
Strain and deformation history in a syntectonic pluton. The case of the Roses granodiorite (Cap de Creus, Eastern Pyrenees)
Authors: Carreras J. , Druguet E. , Griera A. , Soldevila J. 
Published: April 2008

Abstract
The Roses granodiorite is a Variscan stock with well developed syn- and post-magmatic deformation structures that crops out in the Pyrenean Axial Zone. Analysis of structures reveals a continuous deformation history during and after magma cooling. The deformation history is divided on the basis of mechanical behaviour into two stages: an early one with the development of magmatic structures and a late stage with the development of mylonitic fabrics along shear zones. Both stages are separated in time by the emplacement of aplite-pegmatite dykes. Time of dyke emplacement is thought to coincide with a sudden change in rheology of the granodiorite. The abundance of quartz dioritic enclaves permits the use of shape analysis to characterize the magmatic fabric as a homogeneous deformation. Later solid-state deformation led to the development of an inhomogeneous deformation pattern with different sizes of anastomosing shear zones wrapping around lozenge-shaped domains. The displacement/width ratio measured in shear zones ranges between one and two orders of magnitude. The Roses granodiorite is thought to be a synkinematically emplaced stock which records a continuous deformatioinal history with two distinct deformation stages, both recording bulk finite strains of similar order of magnitude but with a marked difference in finite strain distribution.
The water-related work of William Smith (1769–1839)
Authors: Torrens H. S. 
Published: April 2008

Abstract
In 1797 Smith recorded his first known ‘Order of Strata’. This was based on his work as a land, colliery and canal surveyor around Bath, Somerset. It already shows a clear awareness of the occurrence of spring lines (especially in the Fuller’s Earth, soon to cause such problems in the construction of the Somerset Coal Canal). In his better known June 1799 version, Smith much extended this, with a new third column showing springs, now tabulated for five of his 23 strata. Smith thus had a keen awareness of both the importance of, and the problems raised by, how water was, or was not, retained in rocks and how it was released at stratigraphically controlled spring lines. This paper briefly reviews five of his involvements with ‘water-related’ geology. The first was as canal engineer. Here one of the two branches of his first canal later had to be abandoned because it could not be made to retain water where it passed over the Dolomitic Conglomerate. The second was as a land drainer. This he first attempted at Camerton in about 1796. This skill brought him most of his early employments after his dismissal from canal work in June 1799. Third, Smith was next a significant exponent of the art of creating water meadows, particularly in Bedfordshire and Norfolk. Smith was active next in a fourth field, erecting sea defences along the east coast of England. Finally he was often consulted on how to find or control new water supplies, as at Swindon or Scarborough. It was this last work which used his stratigraphic skills to their fullest extent.
Joseph Lucas (1846–1926) — Victorian polymath and a key figure in the development of British hydrogeology
Authors: Mather J. D. , Torrens H. S. , Lucas K. J. 
Published: April 2008

Abstract
Joseph Lucas joined the Geological Survey in 1867 and spent almost 9 years mapping in Yorkshire. Forced to resign in ignominious circumstances, for the rest of his life he earned his living advising on groundwater supplies. In 1874 he was the first to use the term hydrogeology in its modern context and defined this new subject in a series of papers in the 1870s. He drew the first British maps showing groundwater contours and described how to carry out a hydrogeological survey. For many years he lobbied for such a survey to be carried out over the whole country and for it to be used as a basis for water resource planning. He was an accomplished linguist, translating material from a variety of European languages, and wrote books on natural history and genealogy. He and his family lived at Tooting, in south London, where he is buried in the Churchyard of Saint Nicholas.
British hydrogeologists in West Africa — an historical evaluation of their role and contribution
Authors: Hazell Robin 
Published: April 2008

Abstract
The Colonial Office established and funded geological surveys in British West African colonies, from 1903 until self government in c. 1960. Provision of water supplies, at first a minor component of the services provided, later often dominated departmental activities. Understanding of the nature of groundwater mirrored the state of the art elsewhere: supply kept pace with demand. Exploration of sedimentary basins led to development of major aquifers. In the 1930s innovative refinements of geophysical siting and well sinking techniques were developed. From 1980 major water borehole programs were largely supervised by British consultants, who continued to pioneer siting and construction techniques.
Developments in UK hydrogeology since 1974
Authors: Brassington F. C. 
Published: April 2008

Abstract
The last quarter of the 20th century has seen the most rapid development of hydrogeology in terms of both the depth of understanding of hydrogeological processes and of the hydrogeology of Britain, with an associated rapid growth in the number of people employed as professional hydrogeologists in the UK. The four main influences that brought about these developments are changes in the structure of the UK water industry and environmental regulators, particularly in England and Wales; influences of EC directives on UK environmental regulation; a growing public awareness of environmental issues and the pressure they applied on successive governments; and developments in computing power, software development and electronic instrumentation. The paper examines the fields in which hydrogeologists have worked during the last three decades and concludes that it has been the richest period for hydrogeological achievement in the history of the science.
The Central Asian Orogenic Belt and growth of the continental crust in the Phanerozoic
Authors: Jahn Bor-Ming 
Published: April 2008

Abstract
Asia is the world’s largest composite continent, comprising numerous old cratonic blocks and young mobile belts. During the Phanerozoic it was enlarged by successive accretion of dispersed Gondwana-derived terranes. The opening and closing of palaeo-oceans would have inevitably produced a certain amount of fresh mantle-derived juvenile crust. The Central Asian Orogenic Belt (CAOB), otherwise known as the Altaid tectonic collage, is now celebrated for its accretionary tectonics and massive juvenile crustal production in the Phanerozoic. It is composed of a variety of tectonic units, including Precambrian microcontinental blocks, ancient island arcs, ocean island, accretionary complexes, ophiolites and passive continental margins. Yet, the most outstanding feature is the vast expanse of granitic intrusions and their volcanic equivalents. Since granitoids are generated in lower-to-middle crustal conditions, they are used to probe the nature of their crustal sources, and to evaluate the relative contribution of juvenile v. recycled crust in the orogenic belts. Using the Nd-Sr isotope tracer technique, the majority of granitoids from the CAOB can be shown to contain high proportions (60 to 100%) of the mantle component in their generation. This implies an important crustal growth in continental scale during the period of 500–100 Ma. The evolution of the CAOB undoubtedly involved both lateral and vertical accretion of juvenile material. The lateral accretion implies stacking of arc complexes, accompanied by amalgamation of old microcontinental blocks. Parts of the accreted arc assemblages were later converted into granitoids via underplating of basaltic magmas. The emplacement of large volumes of post-accretionary alkaline and peralkaline granites was most likely achieved by vertical accretion through a series of processes, including underplating of basaltic magma, mixing of basaltic liquid with lower-crustal rocks, partial melting of the mixed lithologies leading to generation of granitic liquids, and followed by fractional crystallization. The recognition of vast juvenile terranes in the Canadian Cordillera, the western US, the Appalachians and the Central Asian Orogenic Belt has considerably changed our view on the growth rate of the continental crust in the Phanerozoic.
Nb-depleted, continental rift-related Akaz metavolcanic rocks (West Kunlun): implication for the rifting of the Tarim Craton from Gondwana
Authors: Yuan Chao , Sun Min , Yang Jingsui , Zhou Hui , Zhou Mei-Fu 
Published: April 2008

Abstract

The Akaz metavolcanic rocks of the West Kunlun Mountains possess low to intermediate SiO
2
(42.3–64.7 wt%) and MgO (2.69–7.54 wt%) and high TiO
2
(0.94–3.05 wt%) and Fe
2

O
3
T

(7.64–18.47 wt%), indicating a basaltic to andesitic protolith. These rocks have high contents of Zr (89.6–470 ppm), Nb (10.0–40.3 ppm), Y (19.7–52.7 ppm), Th (0.86–15.96 ppm) and total REE (67.7–407 ppm), and are characterized by relatively high Ti/Y (183–649), Th/Yb (0.5–3.9), and low Hf/Ta (3.0–8.6) ratios. They are LREE-enriched (La/Yb = 5.4–20) and most have small negative Nb anomalies (Nb/Nb* = 0.20–1.16). These characteristics are transitional between within-plate and subduction-related basalts. The relatively high Gd/Yb ratios (1.4–2.9) distinguish these rocks from island-arc tholeiites and the high Zr/Y (3–12), Ta/Yb (0.3–0.7) and low Zr/Nb (<12) ratios strongly support a continental affinity. The protoliths for the Akaz metavolcanic rocks are interpreted to be continental rift basalts formed during rifting of the Tarim Craton from Gondwana. Stratigraphic and palaeontological data indicate that the rifting occurred in Sinian to Cambrian times, roughly contemporaneously with rifting in the East Kunlun and North Qilian orogenic belts farther to the east.
UHP rocks and the Dabieshan Orogenic Belt
Authors: Wang Qingchen , Cong Bolin 
Published: April 2008

Abstract

The Dabieshan Orogenic Belt, which contains ultra-high-pressure (UHP) metamorphic rocks, is the Mesozoic collision zone between the Sino-Korean and Yangtze cratons. With respect to the exhumation of the UHP rocks, the Dabieshan Orogenic Belt can be divided into four units, i.e. allochthonous, parautochthonous, autochthonous and reworked units. The allochthonous unit is composed of UHP rocks. The parautochthonous unit is represented by the non-UHP rocks of the Yangtze sedimentary cover and crystalline basement, as well as an accretionary wedge. The autochthonous unit includes Jurassic and Cretaceous sedimentary and igneous rocks. The reworked unit is characterized by migmatization. The deep structure of the Dabieshan Orogenic Belt is characterized by a Moho offset and dome structure in the middle and upper crust, as recording a compressional state. A northward subduction of the Yangtze craton is evidenced by geological, geophysical and geochemical data. In the formation of the Dabieshan orogenic belt, a precondition is the low density of the subducted continental materials. If the UHP unit is the
piston
to build up the orogenic belt, then the continuous compression between the Sino-Korean and Yangtze cratons is the
motor
to trigger the mountain-building processes.
About this title
Authors: Malpas J , Fletcher C.J.N. , Ali J.R. , Aitchison J.C. 
Published: April 2008

The subject of this Special Publication is one of the most interesting in global geoscience, the tectonic evolution of China. The assemblage of terranes that underlie this part of the world provides outstanding opportunities to elucidate global processes, and many of the factors that shape the Earth's lithosphere are best exemplified by the geology of China and its immediately adjacent areas
In addition, there are geological features that are particular and unique to the region. Some have been the focus of recent attention and have attracted international interest because of their global importance. This volume provides accounts of up-to-date research by Chinese and international geological teams on key aspects of the tectonic evolution of China and its surrounding areas. The papers describe the formation of the geological terranes that make up this part of east Asia, place constraints on plate tectonic models for their assembly and provide accounts of unique geological feature of the subcontinent.
Termination of strike-slip faults at convergence zones within continental transform boundaries: examples from the California Continental Borderland
Authors: Legg M. R. , Kamerling M. J. , Francis R. D. 
Published: April 2008

Abstract
Continental transform plate boundaries are broad, composed of numerous active and subparallel strike-slip fault zones. Irregular geometry along the major transform structure creates convergence and divergence zones within the plate boundary where other strike-slip faults terminate. Some prominent irregularities result from microplate interactions. Relative fault displacement, diminishing to zero at fault terminations, must be accommodated or transferred to other structures, laterally or vertically, away from the fault end-point. Distinct styles of strike-slip fault termination may represent different degrees of vertical strain partitioning within the plate boundary.
The Western Transverse Ranges (WTR) of California mark a major structural discontinuity that cuts at high angle across the Pacific-North America transform boundary. Within the California Continental Borderland, two end-member classes of right-slip fault termination against the WTR are apparent. (1) Several major faults, including the San Clemente, San Pedro Basin, Ferrelo and Newport-Inglewood, intersect the southern boundary of the WTR at high angles, with negligible to minor local deflection and minor dissipation of right shear at the Earth’s surface. These faults are inferred to cut through the entire borderland crust and continue in the lower crust beneath the WTR, as evident in geophysical data. These ‘blind’ near vertical faults may control segmentation and earthquake activity on the overlying west-trending WTR structures. (2) In contrast, the Palos Verdes and possibly Whittier faults appear broadly deflected westward to merge at low angle with WTR structure. NW-trending faults rotate counterclockwise, away from the axis of principal shortening as observed in pure shear models, and slip is dissipated through folding, thrust transfer and rotation. Deflected faults are inferred to be predominately upper crustal features, detached from the lower crust and unable to underthrust the WTR. These two distinct right-slip fault termination styles, and associated convergent structures, suggest that basal shear drives vertical-axis rotation of the WTR block over the underthrust Inner Borderland plate. Furthermore, the lower plate, slivered by these right-slip faults, is incompletely coupled with the Pacific plate.
Distributed strike-slip faulting, block rotation and possible intracrustal vertical decoupling in the convergent zone of SW Japan
Authors: Fabbri Olivier , Iwamura Kazumasa , Matsunaga Satoshi , Coromina Guilhem , Kanaori Yuji 
Published: April 2008

Abstract
Between the Median Tectonic Line (MTL) and the Japan Sea, the western Chugoku region of SW Japan is cut by a series of N45°E first-order faults and oblique (N60°–N170°E) second-order faults. This fault network, probably formed during Late Cretaceous-Palaeocene times (70–60 Ma), defines a regional block structure. Pre-Plio-Quaternary kinematical indicators suggest left-lateral motion along the first-order faults and right-lateral motion along some of the second-order faults. Geomorphological evidence and earthquake focal mechanisms indicate that Plio-Quaternary slip senses are opposite to Pre-Plio-Quaternary ones.
The overall fault pattern is geometrically and kinematically similar to patterns obtained by experimental modelling of simple shear deformation distributed at the base of a brittle layer analogue over its entire width. This similarity suggests the possibility of a mid-crustal, flat-lying partial attachment zone which could have controlled the formation of the western Chugoku fault network in Cretaceous to Palaeocene times. The zone, presently inactive, could correspond to the ‘proto-MTL’, a low-angle fault recently imaged by seismic reflection studies and whose trace approximately coincides with the present-day MTL.
Reactivation of the system occurred twice after its formation: firstly in Miocene times, during the opening of the Japan Sea and concomitant clockwise rotation of the entire SW Japan arc; and secondly in Late Pliocene to Quaternary times, after a shift of the relative direction of convergence between the Philippine and Eurasia plates. Unlike the first reactivation, the second reactivation led to an inversion of the sense of slip along the faults.
A re-evaluation of the relationship between trace fossils and dysoxia
Authors: Martin Kate D. 
Published: April 2008

Abstract

Geochemical and palaeontological methods are used to determine the oxygenation histories of Jurassic sequences at Ravenscar, North Yorkshire, and Lyme Regis, Dorset. The ichnology of these sequences is compared with interpreted oxygen levels, allowing current models of oxygen-related trace fossil occurrence to be tested. These case studies support pre-existing models of trace fossil occurrence in demonstrating that burrow diversity, diameters and depth of infaunal tiering increase with increasing oxygen levels. The case studies suggest that trace fossil ethologies may not always be a reliable indicator of palaeo-oxygenation: in some cases, substrate consistency may have a greater influence over ethology than oxygen levels.
Chondrites
is confirmed as a common constituent of dysoxic settings; however, other trace types may also be indicative of such settings.