bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite Element Analysis of the Thermal and Mechanical Behaviors of Bolted Joint
Authors: Fukuoka Toshimichi
Published: October 2008

Mechanical and thermal behaviors of the bolted joint subjected to thermal load are analyzed using axisymmetric FEM, where the effects of thermal contact resistance at the interface and heat flow through small gaps are taken into account in order to accurately evaluate the variations of bolt preloads. It is expected that the numerical procedure proposed here provides an effective means for estimating the strength of such critical structures as internal combustion engines, pressure vessels, steam and gas turbines, etc. An empirical equation that can compute the thermal contact coefficient at the interface composed of common engineering materials has been proposed in the previous paper. In this study, a simple equation for evaluating the amounts of heat flow through small gaps is shown by defining apparent thermal contact coefficient. A finite element approach has been established by incorporating the aforementioned thermal contact coefficients into the finite element formulation. By use of the FE code, it is shown that among various thermal properties, coefficient of linear expansion has dominant effects on the variations of bolt preloads. The validity of the numerical approach is demonstrated by experimentation.
Investigation of Constraint Effects on Fracture Toughness for CC(T) Specimens
Authors: Siegele Dieter , Varfolomeyev Igor , Wallin Kim , Nagel Gerhard
Published: October 2008

Within the framework of the European research project VOCALIST, centre cracked tension, CC(T), specimens made of an RPV steel were tested and analysed to quantify the influence of local stress state on fracture toughness. The CC(T) specimens demonstrate a significant loss of crack tip constraint resulting in a considerable increase in fracture toughness as compared to standard fracture mechanics specimens. So, the master curve reference temperature, To, determined on the basis of CC(T) tests performed in this study is about 43°C lower than To obtained on standard C(T) specimens. Finite element analyses of the tests revealed that the above experimental finding is in a good agreement with the empirical correlations between the reference temperature shift and the crack tip constraint as characterised by the T-stress or Q parameter (Wallin, 2001; Wallin, 2004). The results of this work are consistent with a number of other tests performed within the VOCALIST project and contribute to the validation of engineering methods for the crack assessment in components taking account of constraint.
Engineering Assessment of Constraint Effects on Cleavage Fracture
Authors: Sherry Andrew , Hooton Dennis , Lidbury David
Published: October 2008

It is well known that material fracture toughness is influenced by factors including loading mode and crack size that influence the level of stress triaxiality ahead of the crack tip. This so-called “constraint effect” has been demonstrated both experimentally and analytically, with low constraint (low stress triaxiality) conditions leading to enhanced fracture toughness. Two-parameter fracture mechanics has been developed to provide a framework within which to assess the influence of constraint on safety margins for shallow structural defects. However, this requires the availability of a significant amount of plant-specific material with which to measure the materials’ constraint sensitivity experimentally. This paper presents a case study where constraint effects on cleavage fracture toughness of a shallow-cracked biaxially loaded bend specimen are assessed through a combination of modelling and miniaturised testing. The assessment is performed using the Failure Assessment Diagram approach of R6. It is concluded that the approach provides a practical engineering method for assessing the likely magnitude of constraint effects for low constraint configurations.
Effect of In-Plane Constraint and Type of Loading on Fracture Toughness of Two RPV Steels of PWRs
Authors: Lauerova D. , Brumovsky M.
Published: October 2008

In the paper, results obtained from testing of small specimens performed within VOCALIST project at NRI Rez are presented. The VOCALIST project covered examination of constraint effect on fracture toughness for two steels representing materials of reactor pressure vessel: material A, i.e. steel of 22NiMoCr 3 7 type (similar to ASTM A 508 Grade 3 Class I), and material D, i.e. ferritic steel A533B in aged condition. At NRI Rez, a total of 79 small fracture specimens were tested, the specimens contained either shallow or deep cracks, and both tension and bending types of loading were examined. For the individual groups of specimens (bending/tension specimens with deep/shallow cracks from material A/D) Master Curve reference temperatures T0 were determined. For material D, smaller values of T0 for tension than for bending were found, both for deep and shallow cracks. J-Q loci for material A and D for selected temperatures were constructed and are presented in the paper. Also, in connection with construction of J-Q loci, the problems with determination of Q-stress parameter with respect to value of standardized distance rσ0/J are addressed.
The Impact of a Reactor Vessel Upper Head Temperature Reduction Program on Cracking Potential and Inspection of Alloy 600 Closure Head Penetrations
Authors: Forsyth David R. , Strauch Pat L. , Kreitman Paul J.
Published: October 2008

Primary water stress corrosion cracking (PWSCC) of Alloy 600 reactor pressure vessel closure head penetrations is very sensitive to a number of material and service parameters. Plant experience to date does indicate that time at elevated temperatures is a strong indicator of cracking potential. As a result, lowering temperatures can be an effective way to increase the time for crack initiation, to reduce the rate of crack propagation, to reduce the number of required closure head penetration inspections and to extend the useful life of an existing closure head or a replacement closure head. In this paper, the reactor coolant flow paths into and out of the upper head region of a pressurized water reactor are presented along with the field modifications performed to reduce the upper head region temperature. These modifications are known as an Upper Head Temperature Reduction (UHTR) program. In addition, a simplified model for assessing the impact of temperatures on the potential for crack initiation and crack growth of Alloy 600 closure head penetrations is presented. The impact of a UHTR program and the resulting reduced temperature on crack initiation, as measured by effective degradation years (EDYs), and on crack growth is also discussed. Actual UHTR implementation designs and recent Westinghouse UHTR field modification experiences are also presented.
Unified Interpretation of Crack Growth Rates of Ni-Base Alloys in LWR Environments
Authors: Lu Zhanpeng , Shoji Tetsuo
Published: October 2008

Primary water stress corrosion cracking (PWSCC) of Vessel Penetrations (VP) fabricated from nickel based alloys such as alloy 600 and alloy 182 weld metal has created a great demand for elucidation of the cracking mechanism and for development of life prediction technologies. The generalized FRI crack growth rate (CGR) formulation was proposed, based on a deformation/oxidation mechanism and a theoretical crack tip strain rate equation derived by the authors. The effects of crack tip oxidation and crack tip mechanics and of their interactions on crack growth can be quantified. Experimental and actual plant data of CGR for alloy 600 in PWR primary water, which are sometimes scattered in CGR-K diagrams, are interpreted with the generalized CGR formulation, emphasizing the effects of temperature, K, yield strength and variations of K with time. It is suggested that it is essential to determine the type of dependency of CGR on K for accurate flaw disposition. The generalized formulation provides a unique parameter for interpreting CGRs as well as a unified method for predicting CGRs within a narrow scattered band even under various testing parameters, which is the basis for accurately predicting component life.
Materials in Support of a Newly Emerging Hydrogen Infrastructure
Authors: Hayden Louis E. , Tverberg John C.
Published: October 2008

There is an ever-increasing need to explore the use of hydrogen as a renewable energy source. Attendant to this expansion is the need to evaluate the currently used materials for the transport and storage of hydrogen to meet these needs. Historically, most pipelines were constructed using various carbon steels. Carbon steels are susceptible to hydrogen embrittlement, high ductile to brittle transition temperature, and hydrogen induced cracking. Other materials evaluated include austenitic stainless steel, aluminum, nickel alloys and fiber reinforced composite materials.
Multiplex Immunoassay for Serological Diagnosis of
Mycobacterium bovis
Infection in Cattle
Authors: Whelan Clare , Shuralev Eduard , O'Keeffe Grainne , Hyland Paula , Kwok Hang Fai , Snoddy Philip , O'Brien Amanda , Connolly Marie , Quinn Padraig , Groll Matt , Watterson Todd , Call Sara , Kenny Kevin , Duignan Anthony , Hamilton Mary Jo , Buddle Bryce M. , Johnston James A. , Davis William C. , Olwill Shane A. , Clarke John
Published: October 2008

Efforts to develop a better diagnostic assay for bovine tuberculosis have shown that the sensitivity and specificity of an assay can be improved by the use of two or more antigens. As reported here, we developed a multiplex chemiluminescent immunoassay that can simultaneously detect antibody activity to 25 antigens in a single well in a 96-well plate array format. The chemiluminescent signal is captured with a digital imaging system and analyzed with a macro program that tracks each serum for its pattern of antibody activity for
Mycobacterium bovis
antigens. The comparison of sera from 522 infected and 1,489 uninfected animals showed that a sensitivity of 93.1% and a specificity of 98.4% can be achieved with a combination of antigens. The assay system is rapid and can be automated for use in a centralized laboratory.
Association of white blood cell subfraction concentration with fitness and fatness
Authors: Johannsen N M , Priest E L , Dixit V D , Earnest C P , Blair S N , Church T S
Published: October 2008

Objective

To examine the association between fitness, BMI, and neutrophil, lymphocyte, monocyte, basophil, and eosinophil concentrations in apparently healthy, non-smoking men.

Design

Cross-sectional study of 452 men from the Aerobics Center Longitudinal Study examining the resting concentration of white blood cell subfractions across fitness (maximal METs during a treadmill exercise test) and fatness (BMI) categories after adjusting for age.

Results

Fitness was inversely associated with all WBC subfraction concentrations. After further adjustment for BMI, only total WBC, neutrophil, and basophil concentrations remained significantly associated with fitness. BMI was directly associated with total WBC, neutrophil, lymphocyte, monocyte, and basophil concentrations and, when fitness was added to the model, only monocytes lost significance.

Conclusion

Fitness (inversely) and fatness (directly) are associated with WBC subfraction populations.
Female soccer referees selected for the FIFA Women’s World Cup 2007: survey of injuries and musculoskeletal problems
Authors: Bizzini M , Junge A , Bahr R , Dvorak J
Published: October 2008

Background:

Few studies have examined the physiology, training and more recently injury profile of the soccer referee, and these have involved almost exclusively male referees.

Purpose:

To analyse the frequency and characteristics of injuries and musculoskeletal problems in female referees selected for the FIFA Women’s World Cup 2007.

Study design:

Retrospective and prospective descriptive epidemiological study.

Methods:

During the preparation camps a few months before the FIFA Women’s World Cup 2007, all 81 preselected female referees completed a questionnaire on injuries and musculoskeletal problems. During the final 32 matches of the tournament in China, all injuries, musculoskeletal problems and related treatment of the 36 officiating referees were documented.

Results:

Almost 50% of the referees reported having incurred at least one injury during their career that had led to time loss from the game. In the previous 12 months, 13 (16%) referees reported having sustained an injury and 64 (79%) reported musculoskeletal problems related to refereeing. During the World Cup and 14 (39%) referees incurred an injury and 17 (33%) were treated for musculoskeletal problems. The commonest location of injuries and problems were hamstrings, quadriceps, calf and ankle. The prospectively collected data found an incidence of 34.7 match injuries per 1000 match hours (95% CI 4.2 to 65.1).

Conclusion:

Top-level female referees are exposed to an even greater risk of injury and/or musculoskeletal problems related to officiating than are male referees. Considering the growth of women’s soccer, injury prevention programmes should be specifically developed for female referees.
Performance of Concrete Containing a Variety of Black Shale
Authors: Bérard Jean , Roux Richard , Durand Marc
Published: October 2008

The combined mechanisms of oxidation of iron sulfides followed by sulfatation of both the surrounding calcite and the hydration products of Portland cement are well known. Nevertheless, cases where important breakdown of concrete structures have occurred, with less than 2% shale in the coarse aggregate fraction seem to be very rare.Based mainly on petrographic examination, the expansive mineral phases were identified in the black shale and in the concrete paste. It is believed that sulfuric acid, formed within the shale by oxidation of the pyrrhotite, has transformed the calcite into gypsum. In the concrete, this newly formed gypsum or that formed by sulfatation of the portlandite Ca(OH)2 has reacted in turn with the tricalcium aluminate of the cement paste to form ettringite. Both reactions, within the shale or with the cement paste, occur with an important volume increase.
Safety factors in soil mechanics
Authors: Meyerhof G. G.
Published: October 2008

The influences on the safety margin in earthwork and foundation engineering are considered in relation to soil exploration and tests, analysis of stability under the applied loads, and construction and operation of the structure during its service life. Customary overall and suggested partial safety factors used in stability analyses are mainly governed by the variability and uncertainty of assessment of the soil resistance, the variability of the applied loads, approximations in the stability analyses, and the seriousness of a failure. On the basis of probability concepts of safety, the conventional overall safety factors used in earthwork and foundation engineering analyses are related to approximate probabilities of stability failure and to a range of overall coefficients of variation, which are consistent with the range of observed coefficients of variation of the soil resistance, applied loads, and stability analyses.
RELIABILITY MODEL FOR COMPONENT-BASED SYSTEMS IN COSMIC (A CASE STUDY)
Authors: ORMANDJIEVA OLGA , ABU TALIB MANAR , ABRAN ALAIN
Published: October 2008

Software component technology has a substantial impact on modern IT evolution. The benefits of this technology, such as reusability, complexity management, time and effort reduction, and increased productivity, have been key drivers of its adoption by industry. One of the main issues in building component-based systems is the reliability of the composed functionality of the assembled components. This paper proposes a reliability assessment model based on the architectural configuration of a component-based system and the reliability of the individual components, which is usage- or testing-independent. The goal of this research is to improve the reliability assessment process for large software component-based systems over time, and to compare alternative component-based system design solutions prior to implementation. The novelty of the proposed reliability assessment model lies in the evaluation of the component reliability from its behavior specifications, and of the system reliability from its topology; the reliability assessment is performed in the context of the implementation-independent ISO/IEC 19761:2003 International Standard on the COSMIC method chosen to provide the component's behavior specifications. In essence, each component of the system is modeled by a discrete time Markov chain behavior based on its behavior specifications with extended-state machines. Then, a probabilistic analysis by means of Markov chains is performed to analyze any uncertainty in the component's behavior. Our hypothesis states that the less uncertainty there is in the component's behavior, the greater the reliability of the component. The system reliability assessment is derived from a typical component-based system architecture with composite reliability structures, which may include the composition of the serial reliability structures, the parallel reliability structures and the p-out-of-n reliability structures. The approach of assessing component-based system reliability in the COSMIC context is illustrated with the railroad crossing case study.
SAMPLING EFFECTS ON THE EMPIRICAL MODE DECOMPOSITION
Authors: RILLING GABRIEL , FLANDRIN PATRICK
Published: October 2008

Standard exposition of Empirical Mode Decomposition (EMD) is usually done within a continuous-time setting whereas, in practice, the effective implementation always operates in discrete-time. The purpose of this contribution is to summarize a number of results aimed at quantifying the influence of sampling on EMD. The idealized case of a sampled pure tone is first considered in detail and a theoretical model is proposed for upper bounding the approximation error due to finite sampling rates. A more general approach is then discussed, based on the analysis of the nonlinear operator that underlies the EMD (one step) sifting process. New explicit, yet looser, bounds are obtained this way, whose parameters can be estimated directly from the analyzed signal. Theoretical predictions are compared to simulation results in a number of well-controlled numerical experiments.
ADAPTIVE DATA ANALYSIS OF COMPLEX FLUCTUATIONS IN PHYSIOLOGIC TIME SERIES
Authors: PENG C.-K. , COSTA MADALENA , GOLDBERGER ARY L.
Published: October 2008

We introduce a generic framework of dynamical complexity to understand and quantify fluctuations of physiologic time series. In particular, we discuss the importance of applying adaptive data analysis techniques, such as the empirical mode decomposition algorithm, to address the challenges of nonlinearity and nonstationarity that are typically exhibited in biological fluctuations.
HHT-BASED SIMULATION OF UNIFORM HAZARD GROUND MOTIONS
Authors: WEN Y. K. , GU PING
Published: October 2008

Hilbert–Huang Transform (HHT) is a new analysis method for nonstationary and nonlinear signals. A simulation method based on HHT is used to generate uniform hazard ground motions, which are often needed for nonlinear time history analysis for structures in high-seismic zones. The HHT-based simulation method can reproduce the amplitude and frequency content change with time for nonstationary random processes, thus is very suitable for the simulation of earthquake ground motions, especially the near-fault ground motions with long-period pulses. Monte-Carlo method and historical earthquake records are used for the generation of a large pool of ground motions, from which the uniform hazard ground motions are selected. The regional seismicity and rupture directivity are considered. An example is given of a site near Los Angeles City Hall. The advantages and difficulties of the proposed method are also discussed.
Archaean oil migration in the Witwatersrand Basin of South Africa
Authors: ENGLAND G. L. , RASMUSSEN B. , KRAPEZ B. , GROVES D. I.
Published: October 2008

Abstract:
The Late Archaean Witwatersrand Supergroup of South Africa hosts the largest known gold-uranium-pyrite ore deposits. Oil preserved in fluid inclusions in quartz grains in siliciclastic sedimentary rocks of that supergroup implies that hydrocarbon generation and migration occurred during the Archaean, and may have been involved in mineralization processes. Through reference to Phanerozoic analogues, oil-bearing fluid inclusions entrapped in healed microfractures in detrital quartz grains and in early syntaxial quartz-overgrowths imply, that the onset of oil migration coincided with early to intermediate stages of burial, while intra-granular porosity was still preserved. Multiple generations of oil migration are indicated by: (i) oil inclusions within early diagenetic cements at different levels in the stratigraphic succession; (ii) more than one type of oil in entrapment sites; (iii) oil entrapment in multiple stages of the quartz paragenetic sequence. Oil generation and migration are considered to have occurred throughout, and for some considerable time after, development of the Witwatersrand Basin, consistent with progressive burial and kerogen maturation in more than one tectonic regime. Oil-bearing fluid inclusions within detrital sandstone fragments suggest that oil migration also occurred in a sedimentary succession on the Kaapvaal Craton prior to 2.9 Ga. Oil in the Witwatersrand Supergroup was most likely derived from multiple source areas, with the principal source probably being shales within the lower Witwatersrand Supergroup. The hydrocarbon migration history of the basin has important implications for understanding the textural relationship between gold, bituminized oil and uraninite in the giant gold-uranium-pyrite ore deposits.
Atmospheric pCO
2
and depositional environment from stable-isotope geochemistry of calcrete nodules (Barremian, Lower Cretaceous, Wealden Beds, England)
Authors: ROBINSON STUART A. , ANDREWS JULIAN E. , HESSELBO STEPHEN P. , RADLEY JONATHAN D. , DENNIS PAUL F. , HARDING IAN C. , ALLEN PERCE
Published: October 2008

Abstract:
Nodular soil carbonates (calcretes) are present in overbank facies of Lower Cretaceous, non-marine Wealden Beds (Wessex Formation) of southern England. Field evidence suggests that these calcretes formed mostly under semi-arid Mediterranean-type climatic conditions. Typical calcrete fabrics, identified petrographically, include floating detrital grains, corroded grain margins and circumgranular cracks defining peds. Localized alteration of primary micrites is mainly associated with large cracks where early non-ferroan diagenetic cementation and neomorphism was focused. Diagenetic ferroan calcites occur as void fills and yield relatively light carbon-isotope and oxygen-isotope compositions (
δ
13
C= −15.0‰;
δ
18
O= –6.3‰) compared to well-preserved micrite (
δ
13
C= –10.2‰;
δ
18
O= –4.0‰). Precise definition of
δ
13
C values for well-preserved micrites allow estimation of partial pressure of atmospheric CO
2
(
p
CO
2
) for the early Barremian of 560 ppmV using a published diffusion-reaction model. The data suggest that atmospheric CO
2
was low during the mid-Early Cretaceous before rising to a previously defined mid-Cretaceous high. Data from calcretes in the Weald Clay highlight the need for selection of appropriate material and careful evaluation before
p
CO
2
calculations are attempted. The Weald Clay samples come from marshy palaeoenvironments where ingress of atmospheric CO
2
into the soil-zone was either reduced or prevented.
Thrust-wedge mechanics and coeval development of normal and reverse faults in the Himalayas
Authors: SHANKER D. , KAPUR N. , SINGH BHAWANI
Published: October 2008

Abstract:
The coeval development of the South Tibetan Detachment (a regional-scale normal fault in Tibet) and the Main Central Thrust together with the observed dominance of thrusting in the Himalayas, is modelled using stress simulation analysis. 2D non-linear elastic and homogeneous wedge models, representing cross-sections of the Himalayas and Tibet are used. Simulated stresses for a set of boundary conditions in which the stress magnitudes are sufficient to cause failure along the wedge base (lower boundary) and reverse faulting at its toe (updip end of the base), invariably lead to the simultaneous development of intra-wedge normal faults. Further, a decrease in shear strength of the wedge base relative to its interior favours the development of normal faults and/or reduction in the magnitude of thrusting stresses within the wedge. These results suggest that the presence of a relatively strong Main Himalayan Thrust, the plate boundary fault below the Himalayas, would have favoured the occurrence of thrusting in the wedge. Moreover, a weak Main Himalayan Thrust below Tibet along with initiation of the Main Central Thrust can explain coeval development of the South Tibetan Detachment.
Mid-crustal partitioning and attachment during oblique convergence in an arc system, Palaeoproterozoic Ketilidian orogen, southern Greenland
Authors: GARDE ADAM A. , CHADWICK BRIAN , GROCOTT JOHN , HAMILTON MICHAEL A. , McCAFFREY KENNETH J. W. , SWAGER CEES P.
Published: October 2008

Abstract:
The Ketilidian orogen in SE Greenland contains a continental magmatic arc (Julianehåb batholith) and forearc which formed in the overriding plate of a Palaeoproterozoic oblique subduction boundary between
c.
 1854 and 1795 Ma. During uplift and deformation of the forearc between
c.
 1795 and 1780 Ma, its sedimentary sequences were invaded by arc-type magmas and metamorphosed at HT–LP upper amphibolite facies conditions which led to widespread anatexis and generation of abundant S-type granites. Transpression during early deformation (D
1
) was partitioned into arc-parallel, sinistral strike-slip in the magmatic arc rocks of the batholith and arc-normal contraction in the sedimentary and volcaniclastic sequences of the proximal forearc (Psammite Zone). Subsequently, D
1
fabrics in the Psammite Zone were overprinted and transposed in an intense, flat-lying, D
2
ductile shear zone with arc-parallel stretching lineations and top-NE kinematic indicators. The kinematic significance of the D
2
shear zone is that it accommodated vertical differences in strain and displacement and permitted deformation to be partitioned differently at different levels in the crust. As such, it is an attachment or coupling zone that provided kinematic linkage between deformation at different crustal levels during NE transport of a forearc sliver. Overprinting of the upper crustal domain of D
1
strike-slip partitioned transpression in the forearc during D
2
is attributed to migration of the attachment zone to a higher crustal level. This migration was a consequence of an enhanced geothermal gradient in the proximal part of the forearc due to the emplacement of batholith-related plutonic suites during D
2
.
U–Pb geochronology of deformed metagranites in central Sutherland, Scotland: evidence for widespread late Silurian metamorphism and ductile deformation of the Moine Supergroup during the Caledonian orogeny
Authors: Kinny P.D. , Strachan R.A. , Friend C.R.L. , Kocks H. , Rogers G. , Paterson B.A.
Published: October 2008

Within the Caledonides of central Sutherland, Scotland, the Neoproterozoic metasedimentary rocks of the Moine Supergroup record NW-directed D
2
ductile thrusting and nappe assembly, accompanied by widespread tight-to-isoclinal folding and amphibolite-facies metamorphism. A series of metagranite sheets which were emplaced and penetratively deformed during D
2
have been dated using SHRIMP U–Pb geochronology. Zircon ages of 424 ± 8 Ma (Vagastie Bridge granite), 420 ± 6 Ma (Klibreck granite) and 429 ± 11 Ma (Strathnaver granite) are interpreted to date emplacement, and hence regional D
2
deformation, during mid- to late Silurian time. Titanite ages of 413 ± 3 Ma (Vagastie Bridge granite) and 416 ± 3 Ma (Klibreck granite) are thought to date post-metamorphic cooling through a blocking temperature of
c
. 550–500 °C. A mid- to late Silurian age for D
2
deformation supports published models that have viewed the internal ductile thrusts of this part of the orogen as part of the same kinematically linked system of foreland-propagating thrusts as the marginal Moine Thrust Zone. The new data contrast with previous interpretations that have viewed the dominant structures and metamorphic assemblages within the Moine Supergroup as having formed during the early to mid-Ordovician Grampian arc–continent orogeny. The mid- to late Silurian D
2
nappe stacking event in Sutherland is probably a result of the collision of Baltica with the Scottish segment of Laurentia.
Brittle architecture of the Lanterman Fault and its impact on the final terrane assembly in north Victoria Land, Antarctica
Authors: ROSSETTI FEDERICO , STORTI FABRIZIO , LÄUFER ANDREAS L.
Published: October 2008

Abstract:
The Lanterman Fault is one of the subvertical, NW–SE-striking intraplate shear zones that bound the major Proterozoic to Early Palaeozoic tectono-metamorphic blocks constituting north Victoria Land, Antarctica. This fault zone, several kilometres wide and with an onshore along strike length of about 400 km from the Southern Ocean to the Ross Sea, records almost entirely brittle deformation, producing complex, NW–SE- to north–south-trending, anastomosing dextral fault strands. Brittle faulting is subparallel to the regional subvertical schistosity, indicating that it was superimposed in a broad region that has earlier experienced ductile-dominated deformation. The regional-scale brittle deformation fits into a general kinematic model involving progressive NW–SE dextral simple shear. Two major onshore age constraints exist for brittle faulting along the Lanterman Fault system: (i) involvement of Triassic Beacon and Jurassic Ferrar rocks in faulting; and (ii) the intimate link between right-lateral faulting and Cenozoic magmatism along the southern onshore termination of the fault. We infer that final terrane assembly in northern Victoria Land was the response to late-stage (Cenozoic) right-lateral movements along NW–SE inherited structures, rather than being the result of accretion during the Early Palaeozoic Ross Orogeny.
Sedimentation associated with Antarctic Peninsula ice shelves: implications for palaeoenvironmental reconstructions of glacimarine sediments
Authors: Evans J. , Pudsey C. J.
Published: October 2008

Abstract: Recent disintegration of a number of Antarctic Peninsula ice shelves has given us a unique opportunity to investigate sub-ice-shelf sediments. We characterize three sediment facies associations of two Antarctic Peninsula ice shelves (Larsen-A and Larsen Inlet).
Subglacial facies
consist mainly of basal till (diamicton) with high shear strengths deposited under a grounded ice sheet. Progressive upward decrease in shear strength reflects a gradual decrease in the confining vertical effective pressure of grounded ice during till deposition.
Proximal ice-shelf glacimarine facies
(diamicton, gravel-rich and sand-rich facies, gravelly mud, dropstone mud and sandy muds) were deposited by sub-ice-shelf rain out, bottom current activity and sediment gravity flows following decoupling of grounded ice from the sea-floor.
Distal, ice-shelf glacimarine and/or open marine
facies
comprise terrigenous and diatom-bearing bioturbated muds and gravelly muds that contain limited ice-rafted debris; these accumulated after recession of the grounding line to the coast, with coarse-grained surface sediments possibly documenting most recent ice-shelf break-up. Antarctic Peninsula ice-shelf sediments are more heterogeneous than ice-shelf facies deposited elsewhere in Antarctica. Cold, polar Antarctic ice shelves can be differentiated from temperate and sub-polar marine-terminated glacial sedimentary systems by the dominance of coarse-grained proximal, ice-shelf glacimarine facies and an absence of subaqueous outwash/meltwater sediment facies.
Ore genesis age of the Tharsis Mining District (Iberian Pyrite Belt): a palynological approach
Authors: GONZÁLEZ FELIPE , MORENO CARMEN , SÁEZ REINALDO , CLAYTON GEOFFREY
Published: October 2008

Massive sulphide deposits of the Tharsis Mining District (Iberian Pyrite Belt) are included in a black shaly series that is stratigraphically conformable with the underlying Phyllite–Quartzite Group. Well-preserved palynomorph assemblages have been obtained from this shaly series. The miospore assemblages are assigned to the LN Biozone, indicating a latest Devonian age. This is consistent with the Re–Os age of 348.6 ± 12.3 Ma from both massive sulphides and stockwork mineralization. Palynological and isotopic results from elsewhere in the Pyrite Belt are similar, suggesting that mineralization was synchronous throughout the region.
Geochronology of clasts in allochthonous Miocene sedimentary sequences on Mykonos and Paros Islands: implications for back-arc extension in the Aegean Sea
Authors: SÁNCHEZ-GÓMEZ MARIO , AVIGAD DOV , HEIMANN ARIEL
Published: October 2008

In the Cyclades, low-angle normal faults juxtaposed Miocene sedimentary rock units lying over Alpine blueschist- and greenschist-facies metamorphic rocks and Miocene granites. The sedimentary units in the hanging wall were deposited in fault-bounded basins while their footwalls progressively emerged through the ductile and brittle crust.

The sedimentation in the basins evolved from marine turbidites in the Early Miocene to shallow/continental conglomerates during the Late Miocene. The transition from marine to fan delta sedimentation was coeval with widespread magmatism and possibly reflects true crustal uplift. It is inferred that the sequence is no younger than 8 Ma.

K–Ar and
40
Ar/
39
Ar geochronology, petrology and petrography of the clasts deposited on the hanging wall provide proof of progressive exhumation of the footwall and reveal the nature of the overburden that covered the Cycladic blueschist belt during Alpine orogeny in the Tertiary. Abundant metamorphic clasts yielding mica cooling ages between 80 and 100 Ma occur throughout the sedimentary section and probably pertain to a vast Pelagonian-type rock mass that covered the internal Hellenides from the Olympos to the central Cyclades. In addition, volcanic clasts dated at 10 Ma reveal the existence of a hitherto unknown volcanic province of that age in the central Aegean. Miocene crustal extension and exhumation of granitic plutons is recorded in the detrital sequence in a concentration of 10 Ma granitic clasts restricted to the top of the conglomerate sequence. A group of metamorphic clasts that yielded ages of 13–16 Ma possibly represents exhumation of mid crustal levels. Clasts similar to the currently-exposed Cycladic Blueschist Unit, such as 40 Ma old blueschists, eclogites and marble, were not found, thus indicating the very late exposure of these footwall rocks.
Lazarus taxa, refugia and relict faunas: evidence from graptolites
Authors: RICKARDS R. B. , WRIGHT A. J.
Published: October 2008

Lazarus taxa are considered to be end members of a common phenomenon and their usefulness is questioned. Mass extinctions are survived by a small number of evolutionary lineages, which give rise to the increase in biodiversity during the recovery phase; and by a small number of species which survived in geographically small, isolated refugia, perhaps marginal to the main environment in crisis. Refugia may give rise to relict faunas, as in the case of early Ludlow graptolites of New South Wales, Australia, but most elements of a relict fauna are short-lived in evolutionary terms.
Emeishan Basalts (SW China) and the ‘end-Guadalupian’ crisis: magnetobiostratigraphic constraints
Authors: ALI JASON R. , THOMPSON GARY M. , SONG XIEYAN , WANG YUNLIANG
Published: October 2008

A magnetostratigraphic investigation of the Permian Emeishan LIP (large igneous province) was carried out on a composite section in Ebian County, close to the type area in Sichuan, SW China. The main succession of twelve flows (175 m thick) carries a normal polarity whilst the one reliable site from the overlying 30 m thick volcanic waning sequence is marked by a reverse polarity. The data enable a correlation to be proposed with an Emeishan Basalt sequence in western Guizhou,
c.
 400 km to the SE. From our knowledge of the geomagnetic field's reversal behaviour during the Permian, it suggests that the main lava pile along the eastern half of the Emeishan Basalt outcrop belt was erupted within a half to one million years. Using magnetobiostratigraphic data from the adjacent South China platform, the normal polarity magnetozone is correlated with the normal polarity chron associated with the upper part of the Maokou Limestones. Constrained by conodont data, the main Emei Basalts appear to be at least two biozones older (1–1.5 Ma) than the Mid–Late Permian boundary. It is possible, however, that the Emei Basalt waning zone sequence, which represents an explosive volcanic phase, might be coeval with the ‘end-Guadalupian’ biotic crisis. Thus arguments implicating Emei Basalt volcanism as the causal mechanism behind this major global event have to accommodate the new relative-age constraints.
Sulphur isotope geochemistry of black shale-hosted antimony mineralization, Arnsberg, northern Rhenish Massif, Germany: implications for late-stage fluid flow during the Variscan orogeny
Authors: Wagner Thomas , Boyce Adrian J.
Published: October 2008

Vein-type and bedding-concordant mesothermal (180–410 °C) stibnite–sulphosalt mineralization at Arnsberg, NE Rhenish Massif, Germany, is hosted by Carboniferous pyrite-rich black shales and siliceous limestones. A detailed sulphur isotope study of the stibnite–sulphosalt mineralization and pyrite from a variety of regional host-rock lithologies has been carried out using an
in situ
laser combustion technique. The
δ
34
S values of stibnite of various textural types are distinctly negative and lie in a narrow range between −23.9‰ and −17.1‰ (mean −20.1‰). In contrast, regional sedimentary–diagenetic pyrites display a large variation of their
δ
34
S values between −45.4‰ and +9.3‰. There is little evidence for significant modification of the hydrothermal fluid during deposition and the S isotope signatures suggest that the sulphur of the stibnite mineralization was not locally derived. The
δ
34
S values of pyrite in Givetian shales display a significantly narrower range of −28.2‰ to −7.5‰ and their mean composition (−17.1‰) is close to the
δ
34
S values of the Arnsberg stibnite deposits. Considering the temperature-dependent isotopic fractionation between stibnite and reduced sulfur species, the
δ
34
S values of the mineralizing fluid (−16.8‰; 200 °C) and the Givetian rock source are essentially identical. Therefore, we propose a model of leaching and isotopic homogenization of sulphur from the Middle Devonian shales and a subsequent northward migration of these fluids. The fluids were trapped in permeability-controlled positions within anticlinal zones, where fluid cooling induced deposition of stibnite and sulphosalts.
The Palaeogene forearc basin of the Eastern Alps and Western Carpathians: subduction erosion and basin evolution
Authors: KÁzmÉr M. , Dunkl I. , Frisch W. , Kuhlemann J. , OzsvÁrt P.
Published: October 2008

Scarce Palaeogene sediment remnants in the Eastern Alps and Western Carpathians are interpreted as remains of a continuous forearc basin. New apatite fission-track geochronological data corroborate mild Paleocene–Eocene exhumation and relief formation in the Eastern Alps. Palinspastic restoration and nine palaeogeographical maps of the Eastern Alps and Western Carpathians ranging from the Paleocene to the Late Oligocene epoch illustrate west to east migration of subsidence in the forearc basin. Subsidence isochrons indicate that oblique subduction of the European plate below the Adriatic plate was responsible for forearc basin migration at a rate of 8 mm a
−1
. The Periadriatic Lineament was formed as a result of shearing by oblique subduction. The Neogene to recent Sumatra forearc basin is an analogue for the evolution of the East Alpine–West Carpathian forearc basin.
Geochemical provinciality in the Cretaceous basaltic magmatism of Northern Madagascar: mantle source implications
Authors: Melluso L. , Morra V. , Brotzu P. , Franciosi L. , Lieberknecht A.M.Petteruti , Bennio L.
Published: October 2008

The northern part of the Late Cretaceous flood-basalt province of Madagascar is formed by lava flows, dykes and intrusive complexes. These range from tholeiitic to weakly alkaline and have composition from basalts to basaltic andesites (with rare, more evolved, rocks). The magmatic evolution is dominated by low-pressure crystal fractionation of olivine, Cr-spinel, plagioclase and clinopyroxene. The erupted rocks form two subprovinces, in terms of incompatible element concentrations or ratios and geographical position. The mafic and intermediate samples from the western subprovince have low abundances of high field strength elements (e.g. Nb 2–9 ppm; Zr 50–230 ppm), negative Nb anomalies on mantle-normalized diagrams, and a wide range of initial (88 Ma)
143
Nd/
144
Nd (0.51293–0.51197;
ε
Nd +7.9 to −10.9). These elemental and isotopic variations are compatible with melting of predominantly N-MORB-like mantle and variable low-pressure crustal contamination. The mafic samples of the eastern subprovince are mildly enriched in incompatible elements (e.g. Nb 6–25 ppm; Zr 109–330 ppm), with the highest values found in tholeiites from the east Mahajanga basin, Tampoketsa Kamoreen and Tamatave. They also have a comparatively narrow range of initial
143
Nd/
144
Nd (0.51276–0.51258;
ε
Nd +5.1 to +1.0), consistent with derivation from incompatible element enriched mantle sources and minor subsequent crustal contamination. The marked differences in the chemical and isotopic characteristics of the samples imply variable degrees of partial melting of hotter than normal, chemically heterogeneous, mantle sources at pressures where spinel to garnet are residual phases. No clear evidence is seen for a chemical component similar to that represented at present by the Marion hotspot lavas.
Northward subduction of the Indian Plate beneath the Kohistan island arc, Pakistan Himalaya: new evidence from isotopic data
Authors: Bignold S.M. , Treloar P.J.
Published: October 2008

The intra-oceanic Kohistan island arc was initiated during the Cretaceous as a result of northward movement of the Indian Plate. The conventional assertion that the arc was erected above a north-dipping subduction zone has been challenged by an alternative hypothesis, which suggests that the arc was built above a south-dipping subduction zone. This hypothesis is based partly on the apparent presence of a ‘Dupal’ signature in mafic rocks of the arc, and partly on the occurrence of boninites exposed in the northern part of the arc. The ‘Dupal’ signature, with enhanced levels of radiogenic lead, is found only in rocks extracted from the mantle in equatorial regions. However, new radiogenic isotope data, presented here, suggest that the isotopic signature of the mafic volcanic rocks of the juvenile arc, rather than being ‘Dupal’-type, is a function of fluids derived from subduction and dehydration of sea-floor sediments. Boninitic volcanic rocks in the Kohistan arc form a volumetrically minor part of a compositionally diverse sequence in the northern part of the arc. Boninites and high-Mg andesites are found mostly, but not exclusively, in the fore-arc region, and evidence is accumulating that these may also be erupted into back-arc regions. Sedimentological and geochemical data suggest the Kohistan boninites to have been erupted into a short-lived back-arc basin. Both the eruption of boninites into the back-arc and the lack of a ‘Dupal’ signature would be consistent with northward subduction beneath Kohistan, although the latitude at which the arc was initiated remains unresolved.
Evidence for a genetic granite–migmatite link in the Dalradian of NE Scotland
Authors: Johnson T.E. , Hudson N.F.C. , Droop G.T.R.
Published: October 2008

The Inzie Head gneisses of the NE Dalradian are syntectonic metapelitic migmatites containing numerous sill-like bodies of granite. Leucosomes preserve evidence for efficient deformation-controlled segregation and interconnection of melt, from intergranular pockets to sheets of leucogranite hundreds of metres thick. Although the physico-chemical system is complex, the geochemistry of
in situ
decimetre-scale leucosomes and discrete metre- to decametre-scale leucogranite sheets within the migmatites suggests derivation from a common metapelitic source. A comparison with spatially and temporally related Grampian Granite plutons and garnet-bearing aplites that occur at shallower crustal levels supports a genetic granite–migmatite link. The compositions of the granitic rocks are interpreted to be linked via fractional crystallization of a parental magma and escape of the fugitive melt from a cumulate residue. Leucogranite sheets within the migmatites have compositions that are similar to experimentally determined first-formed melts at the appropriate
P
–
T
conditions, and are interpreted to approximate parental liquids. Smaller-scale leucosomes contain the accumulated products of fractional crystallization and variable quantities of entrained solids, principally biotite. The Grampian Granites and aplites represent evolved liquids that segregated from source. The evolution of Grampian Granite melts involved varying degrees of K-feldspar-dominated fractional crystallization that is consistent with magma ascent; removal of a maximum of 15–20% cumulate material is implied. The composition of the aplites suggests a multistage evolution that involved plagioclase-dominated fractionation of a fugitive melt batch.
Changing Silurian–Devonian relative plate motion in the Caledonides: sinistral transpression to sinistral transtension
Authors: Dewey J.F. , Strachan R.A.
Published: October 2008

The late Silurian to mid- or late Devonian interval in the Caledonides was a period dominated, sequentially, by sinistral transpression, strike-slip and transtension during the development of mainly non-marine ‘red-bed’ basins following the Ludlow–PrÍdolÍ transition from marine to terrestrial sedimentation. The tectonic event that led to and generated the sinistral Devonian basins was the highly oblique sinistral closure of the Iapetus Ocean between Laurentia and Baltica and between Laurentia and Avalonia. We examine the diachronous closure of Iapetus, the contrasting tectonic modes arising from that closure, and the nature and origin of subsequent Devonian deformation north and south of the Iapetus Suture in the context of progressively changing, sinistrally dominated relative plate motion between Laurentia and Avalonia–Baltica. We suggest that, from about 435 to 395 Ma, there was about 1200 km of sinistral strike-slip relative motion between Laurentia and Baltica. Our lower and upper estimates of Silurian–Devonian relative plate motion rates of 30 mm a
−1
and 67 mm a
−1
based upon geological data, are similar to present rates.