bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimized plasma-deposited fluorocarbon coating for dry release and passivation of thin SU-8 cantilevers
Authors: Keller Stephan , Haefliger Daniel , Boisen Anja
Published: December 2007

Plasma-deposited fluorocarbon coatings are introduced as a convenient method for the dry release of polymer structures. In this method, the passivation process in a deep reactive ion etch reactor was used to deposit hydrophobic fluorocarbon films. Standard photolithography with the negative epoxy-based photoresist SU-8 was used to fabricate polymer structures such as cantilevers and membranes on top of the nonadhesive release layer. The authors identify the plasma density as the main parameter determining the surface properties of the deposited fluorocarbon films. They show that by modifying the pressure during fluorocarbon deposition, the surface free energy of the coating can be tuned to allow for uniform wetting during spin coating of arbitrary thin SU-8 films. Further, they define an optimal pressure regime for the release of thin polymer structures at high yield. They demonstrate the successful release of SU-8 cantilevers and membranes with thicknesses down to 2.3 and 1.7μm respectively, which is a considerable improvement to what has been achieved by dry release of all-polymer structures to date. Furthermore, chemical reaction of the SU-8 with the fluorocarbon coating during processing leads to a considerable increase of the surface free energy on one side of the released cantilevers. This process-integrated back side passivation is interesting for the use of the devices in biosensing applications.
Patterning issues in superconducting nanowire single photon detector fabrication
Authors: Constancias C. , Espiau de Lamaëstre R. , Louveau O. , Cavalier P. , Villégier J.-C.
Published: December 2007

Superconducting single photon detectors (SSPD) made of superconducting NbN ultrathin film were successfully synthesized down to 70nm nanowire width. Their fabrication process is detailed, with emphasis on electron beam lithography. A high-resolution electron beam lithography tool was operated at 100kV in combination with a negative tone resist NEB22A2, in order to achieve the required resolution and fabrication yield. The sensitivity of ultrathin NbN films to various resist stripping treatments is evidenced by electrical transport measurements, and circumvented by deposition of adequate protecting layers. SSPDs made of a 4.4nm thick NbN film were electrically characterized, and show a critical current density above 3×106Acm−2 and a critical temperature above 11K.
Fabrication of three-dimensional structures of resist by proton beam writing
Authors: Furuta Yusuke , Uchiya Naoyuki , Nishikawa Hiroyuki , Haga Junji , Sato Takahiro , Oikawa Masakazu , Ishii Yasuyuki , Kamiya Tomihiro
Published: December 2007

The fabrication of three-dimensional (3D) structures was demonstrated by proton beam writing (PBW) using a MeV light-ion microbeam system at Japan Atomic Energy Agency. The fabrication of the 3D structures was performed using PBW in a thick SU-8 layer with a thickness of up to 50μm, which is a typical negative resist. The authors exposed the negative resist on a silicon substrate to focused MeV proton beams within 1μm in diameter, using two different beam energies to obtain two different depths in the resist aiming at fabrication of 3D structures. The two different beam energies were obtained using a 75μm Kapton film as a beam energy degrader to generate 1.6MeV proton beam from 3.0MeV, or using the accelerator voltage control in order to produce beam energy of 1.2MeV. The 3D lines and space structures with the same shape were fabricated using the two different methods. An Arc de Triomphe shape was also manufactured to demonstrate the superior and unique features of the PBW as a versatile tool for deep micromachining for 3D structures with high aspect ratio.
Annealing of electron beam induced deposits of platinum from Pt(PF3)4
Authors: Ervin Matthew H. , Chang Daniel , Nichols Barbara , Wickenden Alma , Barry John , Melngailis John
Published: December 2007

Electron beam induced deposition (EBID) is of interest as a damage-free and resist-less means of incorporating nonconventional materials such as polymer fibers, nanowires, and carbon nanotubes into integrated circuits. A novel inorganic platinum precursor—Pt(PF3)4—is investigated in this work, as it has previously been demonstrated to deposit Pt with resistivities close to bulk Pt when deposited using high dose rates. In this work, the effects of 100 and 200 °C anneals on these Pt deposits are examined. Annealing these deposits is observed to shrink the deposits and decrease their P content. As a result, the measured Pt resistivities decreased with annealing by factors of 1.6–9.9.
Atomic layer deposited HfO2/HfSixOyNz stacked gate dielectrics for metal-oxide-semiconductor structures
Authors: Kim Seokhoon , Woo Sanghyun , Kim Hyungchul , Jeong Wooho , Park Taeyong , Kim Honggyu , Kim Sung Bae , Jeon Hyeongtag
Published: December 2007

HfSi x O y N z layers were grown on Si substrates prior to HfO2 growth in order to investigate the growth of an interfacial layer between HfO2 and Si substrate and the chemical composition changes at the interfacial region. The effects of the HfSixOyNz buffer layers were also investigated. The HfSixOyNz and HfO2 films were grown by remote plasma atomic layer deposition using N2/O2 plasma and O2 plasma, respectively. The HfSixOyNz films were grown using a TDEAH precursor and N2/O2 mixed plasma. The Hf-N and N-O bonds of the HfSixOyNz layers were easily broken by annealing at 800 °C in N2 ambient because their bonds were relatively weak. The peak intensities of the Si-O-N, Hf-O-Si, and Si-O bonds at the interfacial region increased after annealing. The excess N atoms due to the breaking of the Hf-N and N-O bonds can form bonds with Si atoms in the interfacial region and cause the growth of SiOxNy or SiNx. The excess Hf and O atoms can grow HfSixOy or SiO2 due to interactions with Si atoms. The formation of the HfSixOyNz layer can suppress the growth of Hf silicate or an interfacial layer. The formation of a thick HfSixOyNz layer enhanced the thermal stability of the interfacial layer of the HfO2 film as it had a larger amount of effective fixed oxide charges than a thin HfSixOyNz layer.
Nanostructures using self-assembled multilayers as molecular rulers and etch resists
Authors: Srinivasan C. , Hohman J. N. , Anderson M. E. , Weiss P. S. , Horn M. W.
Published: December 2007

Self-assembled multilayers, composed of alternating layers of α,ω-mercaptoalkanoic acids and Cu2+ ions (“molecular rulers”), are used as organic sidewall spacers and etch resists for the fabrication of registered microstructures with precisely tailored nanometer-scale spacings. The method outlined here eases the stringency of the lithographic processing for patterning second-generation features. Additionally, a new method to lift off the self-assembled multilayered films for the generation of the tailored nanogaps is demonstrated. The advantages of these techniques are discussed.
Coarse-grain simulation of viscous flow and stamp deformation in nanoimprint
Authors: Sirotkin V. , Svintsov A. , Zaitsev S. , Schift H.
Published: December 2007

A refined coarse-grain software for the simulation of thermal nanoimprint lithography is described. This software takes into account the stamp bending during squeeze flow and is able to provide results well suited for the quantitative prediction of the residual resist thickness with an accuracy better than 10%.
Regulation of Replication Fork Progression Through Histone Supply and Demand
Authors: Groth Anja , Corpet Armelle , Cook Adam J. L. , Roche Daniele , Bartek Jiri , Lukas Jiri , Almouzni Geneviève
Published: December 2007

DNA replication in eukaryotes requires nucleosome disruption ahead of the replication fork and reassembly behind. An unresolved issue concerns how histone dynamics are coordinated with fork progression to maintain chromosomal stability. Here, we characterize a complex in which the human histone chaperone Asf1 and MCM2–7, the putative replicative helicase, are connected through a histone H3-H4 bridge. Depletion of Asf1 by RNA interference impedes DNA unwinding at replication sites, and similar defects arise from overproduction of new histone H3-H4 that compromises Asf1 function. These data link Asf1 chaperone function, histone supply, and replicative unwinding of DNA in chromatin. We propose that Asf1, as a histone acceptor and donor, handles parental and new histones at the replication fork via an Asf1–(H3-H4)–MCM2–7 intermediate and thus provides a means to fine-tune replication fork progression and histone supply and demand.
Combinatorial Synthesis of Peptide Arrays onto a Microchip
Authors: Beyer Mario , Nesterov Alexander , Block Ines , König Kai , Felgenhauer Thomas , Fernandez Simon , Leibe Klaus , Torralba Gloria , Hausmann Michael , Trunk Ulrich , Lindenstruth Volker , Bischoff F. Ralf , Stadler Volker , Breitling Frank
Published: December 2007

Arrays promise to advance biology through parallel screening for binding partners. We show the combinatorial in situ synthesis of 40,000 peptide spots per square centimeter on a microchip. Our variant Merrifield synthesis immobilizes activated amino acids as monomers within particles, which are successively attracted by electric fields generated on each pixel electrode of the chip. With all different amino acids addressed, particles are melted at once to initiate coupling. Repetitive coupling cycles should allow for the translation of whole proteomes into arrays of overlapping peptides that could be used for proteome research and antibody profiling.
Role of Intermolecular Forces in Defining Material Properties of Protein Nanofibrils
Authors: Knowles Tuomas P. , Fitzpatrick Anthony W. , Meehan Sarah , Mott Helen R. , Vendruscolo Michele , Dobson Christopher M. , Welland Mark E.
Published: December 2007

Protein molecules have the ability to form a rich variety of natural and artificial structures and materials. We show that amyloid fibrils, ordered supramolecular nanostructures that are self-assembled from a wide range of polypeptide molecules, have rigidities varying over four orders of magnitude, and constitute a class of high-performance biomaterials. We elucidate the molecular origin of fibril material properties and show that the major contribution to their rigidity stems from a generic interbackbone hydrogen-bonding network that is modulated by variable side-chain interactions.
GaN Photonic-Crystal Surface-Emitting Laser at Blue-Violet Wavelengths
Authors: Matsubara Hideki , Yoshimoto Susumu , Saito Hirohisa , Jianglin Yue , Tanaka Yoshinori , Noda Susumu
Published: December 2007

Shorter-wavelength surface-emitting laser sources are important for a variety of fields, including photonics, information processing, and biology. We report on the creation of a current-driven blue-violet photonic-crystal surface-emitting laser. We have developed a fabrication method, named “air holes retained over growth,” in order to construct a two-dimensional gallium nitride (GaN)/air photonic-crystal structure. The resulting periodic structure has a photonic-crystal band-edge effect sufficient for the successful operation of a current-injection surface-emitting laser. This represents an important step in the development of laser sources that could be focused to a size much less than the wavelength and be integrated two-dimensionally at such short wavelengths.
Virtual Reality, Identity Imposters
Authors: Berman Carol W.
Published: December 2007

The Echo Maker
. A Novel.
By Richard Powers
. Farrar, Straus and Giroux, New York, 2006. 459 pp. $25, C$31. ISBN 9780374146351. Heinemann, London, 2007. £17.99. ISBN 9780434016334. Picador, New York, 2007. Paper, $15. ISBN 9780312426439.

The protagonist of this award-winning novel emerges from a coma suffering from Capgras believing that those around him are all impostors, and his condition attracts the attention of a neuroscientist-author.
Time-Resolved Observation and Control of Superexchange Interactions with Ultracold Atoms in Optical Lattices
Authors: Trotzky S. , Cheinet P. , Fölling S. , Feld M. , Schnorrberger U. , Rey A. M. , Polkovnikov A. , Demler E. A. , Lukin M. D. , Bloch I.
Published: December 2007

Quantum mechanical superexchange interactions form the basis of quantum magnetism in strongly correlated electronic media. We report on the direct measurement of superexchange interactions with ultracold atoms in optical lattices. After preparing a spin-mixture of ultracold atoms in an antiferromagnetically ordered state, we measured coherent superexchange-mediated spin dynamics with coupling energies from 5 hertz up to 1 kilohertz. By dynamically modifying the potential bias between neighboring lattice sites, the magnitude and sign of the superexchange interaction can be controlled, thus allowing the system to be switched between antiferromagnetic and ferromagnetic spin interactions. We compare our findings to predictions of a two-site Bose-Hubbard model and find very good agreement, but are also able to identify corrections that can be explained by the inclusion of direct nearest-neighbor interactions.
“Allow natural death” versus “do not resuscitate”: three words that can change a life
Authors: Venneman S S , Narnor-Harris P , Perish M , Hamilton M
Published: December 2007

Physician-written “do not resuscitate” DNR orders elicit negative reactions from stakeholders that may decrease appropriate end-of-life care. The semantic significance of the phrase has led to a proposed replacement of DNR with “allow natural death” (AND). Prior to this investigation, no scientific papers address the impact of such a change. Our results support this proposition due to increased likelihood of endorsement with the term AND.
Developing the duty to treat: HIV, SARS, and the next epidemic
Authors: Dwyer J , Tsai D F-C
Published: December 2007

SARS, like HIV, placed healthcare workers at risk and raised issues about the duty to treat. But philosophical accounts of the duty to treat that were developed in the context of HIV did not adequately address some of the ethical issues raised by SARS. Since the next epidemic may be more like SARS than HIV, it is important to illuminate these issues. In this paper, we sketch a general account of the duty to treat that arose in response to HIV. Our purpose is not to defend or criticise this account, but to show that it needs to be developed in order to address three important issues. The first issue concerns how risks should be distributed among healthcare professionals. The second issue concerns the conflicts that arise between professional duties and family duties. The third issue concerns the forms of support that societies owe healthcare workers during epidemics. Our descriptions of these issues are drawn from our experience of the SARS epidemic in Taiwan.
Against the principle that the individual shall have priority over science
Authors: Helgesson G , Eriksson S
Published: December 2007

This paper highlights a feature common to many ethical guidelines—namely, the idea that the interests of the individual shall always prevail over the interests of science and society. The paper presents how some major ethical guidelines treat the balancing of research interests against those of research subjects and spells out the difficulties in interpreting the principle of the primacy of the individual in a way that can be action-guiding. It suggests various alternative interpretations of the primacy of the individual and argues that they do not hold. Finally, the implications of this analysis for ethical guidelines are discussed.
Low risk research using routinely collected identifiable health information without informed consent: encounters with the Patient Information Advisory Group
Authors: Metcalfe C , Martin R M , Noble S , Lane J A , Hamdy F C , Neal D E , Donovan J L
Published: December 2007

Current UK legislation is impacting upon the feasibility and cost-effectiveness of medical record-based research aimed at benefiting the NHS and the public heath. Whereas previous commentators have focused on the Data Protection Act 1998, the Health and Social Care Act 2001 is the key legislation for public health researchers wishing to access medical records without written consent. The Act requires researchers to apply to the Patient Information Advisory Group (PIAG) for permission to access medical records without written permission. We present a case study of the work required to obtain the necessary permissions from PIAG in order to conduct a large scale public health research project. In our experience it took eight months to receive permission to access basic identifying information on individuals registered at general practices, and a decision on whether we could access clinical information in medical records without consent took 18 months. Such delays pose near insurmountable difficulties to grant funded research, and in our case £560 000 of public and charitable money was spent on research staff while a large part of their work was prohibited until the third year of a three year grant. We conclude by arguing that many of the current problems could be avoided by returning PIAG’s responsibilities to research ethics committees, and by allowing “opt-out” consent for many public health research projects.
PDE APPROACH TO THE VALUATION AND HEDGING OF BASKET CREDIT DERIVATIVES
Authors: RUTKOWSKI MAREK , YOUSIPH KHAN
Published: December 2007

The goal of this work is to examine the PDE approach to the valuation and hedging of defaultable claims in a Markovian model of credit risk. Our approach is based on the previous work by Bielecki et al. [3]. We extend the results in [3] by considering a general credit risk model, in which the number of traded assets, the dimension of the driving Brownian motion, as well as the number of default times are arbitrary.
TERM STRUCTURE OF VANILLA OPTIONS
Authors: BRODY DORJE C. , CONSTANTINOU IRENE C. , MEISTER BERNHARD K.
Published: December 2007

Every maturity-dependent derivative contract entails a term structure. For example, when the value of the portfolio consisting of a long position in a stock and a short position in a vanilla option is expressed in units of its instantaneous exercise value, the resulting quantity defines a discount function. Thus, the derivative of the discount function with respect to the time left until maturity defines a term structure density function, and the "hazard rate" associated with the discount function determines the forward rates for the vanilla option portfolio. The dynamics associated with these quantities are obtained in the complete market setting. In particular, one can model vanilla options based on the associated forward rates. The formulation based on forward rates for options extends the approach based on modeling the implied volatility process. As an illustrative example, the initial term structure of the Black–Scholes model is considered. It is shown in this example that the implied volatility smile has the effect of making the option forward rates homogeneous across different strikes.
SHARPE RATIO MAXIMIZATION AND EXPECTED UTILITY WHEN ASSET PRICES HAVE JUMPS
Authors: CHRISTENSEN MORTEN MOSEGAARD , PLATEN ECKHARD
Published: December 2007

We analyze portfolio strategies which are locally optimal, meaning that they maximize the Sharpe ratio in a general continuous time jump-diffusion framework. These portfolios are characterized explicitly and compared to utility based strategies. We show that in the presence of jumps, maximizing the Sharpe ratio is generally inconsistent with maximizing expected utility, in the sense that a utility maximizing individual will not choose a strategy which has a maximal Sharpe ratio. This result will hold unless markets are incomplete or jump risk has no risk premium. In case of an incomplete market we show that the optimal portfolio of a utility maximizing individual may "accidentally" have maximal Sharpe ratio. Furthermore, if there is no risk premium for jump risk, a utility maximizing investor may select a portfolio having a maximal Sharpe ratio, if jump risk can be hedged away. We note that uncritical use of the Sharpe ratio as a performance measure in a world where asset prices exhibit jumps may lead to unreasonable investments with positive probability of ruin.
ESTIMATION OF OPTICAL PROPERTIES IN BIOLOGICAL TISSUES USING MONTE CARLO SIMULATION
Authors: JAGAJOTHI G. , RAGHAVAN S.
Published: December 2007

In this paper, the optical properties of skin lesion are determined with the help of laser reflectometry. The result is compared with the phantom and simulation values to obtain an accurate result. Surface backscattering is determined by laser reflectometry. The tissue-equivalent phantom is prepared with the help of white paraffin wax mixed with various color pigments in multiple proportions. A familiar Monte Carlo simulation is used to analyze the optical properties of the tissue. The normalized backscattered intensity (NBI) signals from the tissue surface, measured by the output probes after digitization, are used to reconstruct the reflectance images of tissues in various layers below the skin surface. From NBI profiles measured at various locations of the tissues on the forearm, the corresponding optical parameters, the scattering (μ s ) and absorption (μ a ) coefficients, and the anisotropy parameter g are determined by matching these with profiles simulated by the Monte Carlo procedure. The correlation analysis between the lesion thickness and the diffuse reflectance gives the optical wavelengths which are selected for multispectral images of skin lesions. Comparison of results shows the presence of abnormal level in the tissue.
MECHANICS OF INJURY TO MUSCLE FIBERS
Authors: GAO YINGXIN , WAAS ANTHONY M. , WINEMAN ALAN S.
Published: December 2007

An advanced shear lag model is developed to analyze the stress-shielding effect in injured muscle fiber by introducing the activation strain. The model considers three muscle fibers connected by the endomysium with the middle muscle fiber injured. Stress shielding describes the function of the lateral transmission of force in protecting the injured muscle fibers from being further injured by transferring force in the injured muscle fiber to its adjacent muscle fibers. Parameter studies demonstrate that the mechanical and geometrical properties of muscle fibers and the endomysium as well as the degree of injury can affect the stress-shielding effect. In conclusion, the model successfully demonstrates and captures, at least in a qualitative manner, the lateral transmission of force between an injured and a normal muscle fiber.
Geochemical constraints on the sources of Southern Chile Trench sediments and their recycling in arc magmas of the Southern Andes
Authors: Kilian Rolf , Behrmann Jan H.
Published: December 2007

Pliocene and Pleistocene deep-sea trench sediments cored near the Chile Triple Junction (Ocean Drilling Program Leg 141) were analysed for major and trace element concentrations, and for Sr, Nd and Pb isotopic ratios. Comparisons with the potential source rocks of these sediments suggest little alteration during sediment transport and diagenesis. The sediment compositions reflect exposed area fractions and different erosion rates of upper-crustal rock units of the Southern Andes, indicating that denudation, transport and deposition formed an almost closed system since 2.5 Ma. Pelagic sediments cored farther from the continent (>1000 km) on the Antarctic Plate also contain a significant terrigenous component, mixed variably with hydrogenous precipitates (high Fe–Mn–Th), biogenic barite (high Ba) and opal, but little biogenic carbonate (low CaO and Sr). Our sediment data allow us to estimate the subducted sediment input to southern Andean magmas. Mantle sources of basalts from the Andean southernmost Southern Volcanic Zone (41–47°S) were contaminated by 3–5 vol.% of a terrigenous sediment melt with variable amounts of Ba-rich pelagic sediments, but were not contaminated by slab-derived fluids. Adakites of the Andean Austral Volcanic Zone (49–55°S), formed by melting of a relatively hot subducted slab, contain a variable amount of subducted terrigenous sediment (0–20 vol.% sediment melt) and in some cases Ba-rich pelagic sediments.
Crustal contribution to the genesis of Ethiopian plateau rhyolitic ignimbrites: basalt and rhyolite geochemical provinciality
Authors: Ayalew Dereje , Yirgu Gezahegn
Published: December 2007

The Ethiopian continental flood basalt province contains large volumes of felsic eruptive rocks (>6 × 10
4
km
3
) overlying, and sometimes interlayered with the upper parts of the flood basalt sequence. Rb–Sr isochron ages (30.60 ± 0.79 Ma for Lima Limo and 30.17 ± 0.54 Ma for Wegel Tena rhyolite sequences) coincide with the short, well-defined continental flood basalt pulse, indicating rapid emplacement of the rhyolites. Lima Limo rhyolites are characterized by relatively low TiO
2
(0.3–0.5%), Th (5–7 ppm) and Nb (48–68 ppm) concentrations, high Rb/Nb (1.7–3.0) and La/Nb (1.4–2.9) values, non-radiogenic initial
87
Sr/
86
Sr ratios (0.70357–0.70464) and generally negative initial ε
Nd
values (+0.3 to −1.4). In contrast, Wegel Tena rhyolites are characterized by relatively high TiO
2
(0.5–1.0%), Th (10–17 ppm) and Nb (73–115 ppm) abundances, low Rb/Nb (0.8–1.3) and La/Nb (0.8–1.2) values, low initial
87
Sr/
86
Sr ratios (0.70412–0.70469) and positive initial ε
Nd
values (+4.0 to +5.7). The origin of the rhyolite suites is attributed to low-pressure fractional crystallization of basaltic magmas, similar in composition to the exposed flood basalts, combined with assimilation of mafic crustal rocks. Assimilation–fractional crystallization modelling suggests that the genesis of Lima Limo rhyolites involved higher amounts of contamination by crustal material (<14%) relative to those of Wegel Tena (<6%).
The Devonian Nesna shear zone and adjacent gneiss-cored culminations, North–Central Norwegian Caledonides
Authors: Osmundsen P.T. , Braathen A. , Nordgulen Ø. , Roberts D. , Meyer G.B. , Eide E.
Published: December 2007

The Early to Mid-Devonian strain distribution in the Norwegian Caledonides was characterized by large-magnitude extension, extension-normal shortening and sinistral strike-slip. In SW Norway, previous work has shown that the angle between the orogen and the Devonian maximum elongation trend decreases northward towards a zone of sinistral strike-slip. We provide evidence that: (1) late- to post-orogenic extension was much more important in North–Central Norway than recognized previously; (2) the Early to Mid-Devonian, roughly orogen-parallel, maximum elongation trend persisted over more than 200 km farther north than hitherto recognized; (3) a number of gneiss-cored culminations in North–Central Norway were affected by, and probably owe their present geometry to, extensional shearing and faulting. The Nesna shear zone is identified here as a major, late Early to Mid-Devonian, low-angle extensional shear zone in the North–Central Norwegian Caledonides. In the study area, the Nesna shear zone now constitutes the lower boundary of the Helgeland Nappe Complex, a terrane exotic to Baltica. The present situation of the Helgeland Nappe Complex is thus that of an extensional allochthon. The transport direction along the medium- to low-grade Nesna shear zone was top-to-the-WSW, and thus roughly orogen-parallel. Extensional shearing in the Nesna shear zone may provide an explanation for a westward-younging,
40
Ar/
39
Ar cooling pattern previously reported from the Ofoten–Lofoten area. Folding of the Nesna shear zone along axes parallel to the extensional transport direction indicates that extension-normal shortening continued at least into late Early and Mid-Devonian times. The WSW–ENE maximum elongation trend probably persisted in North–Central Norway through most of the Devonian period, and accompanied the transition from ductile to brittle deformation in the rocks of the Caledonian nappe-stack. Deformation in low-angle, initially medium-grade, extensional shear zones such as the Nesna shear zone was succeeded by shearing in steeper, low-grade, ductile-to-brittle shear zones that developed along the western margins of gneiss-cored culminations. Temporal overlap between activity in the Nesna shear zone and in the lower-grade shear zones that bound the culminations can be demonstrated. To the east, however, medium-grade extensional shear zones such as the present boundary between the Seve and Köli nappes were probably back-rotated as the culminations developed in the footwall of the low-grade shear zones. From the Mid–Late Devonian to Early Carboniferous, the low-grade, culmination-bounding shear zones constituted the eastern margin of a regional, transtensional system bounded in the south by the sinistral Møre–Trøndelag Fault Complex.
Grenvillian age decompression of eclogites in the Glenelg–Attadale Inlier, NW Scotland
Authors: Brewer T.S. , Storey C.D. , Parrish R.R. , Temperley S. , Windley B.F.
Published: December 2007

The Glenelg–Attadale Inlier is the largest basement inlier within the Caledonian Moine nappe of NW Scotland. In the eastern part of the inlier amphibolite-facies retrogression of the eclogites is associated with tectonic fabrics, and
P
–
T
estimates indicate significant decompression (
c
. 20 km). Previous Sm–Nd mineral–whole-rock dates indicated that peak eclogite-facies metamorphism occurred around
c
. 1.08 Ga, which was correlated with the Grenvillian orogeny. However, the middle REE enrichment of the analysed garnets suggests the influence of apatite inclusions. It is therefore likely that the interpretation of the
c
. 1.08 Ga age is complex, possibly reflecting re-equilibration at lower temperatures. Sampled eclogites contain zircon in a number of distinct textural forms that are mainly associated with pargasite and plagioclase, and are part of the retrograde amphibolite-facies assemblages. Titanite extensively replaces rutile, and is clearly associated with the retrograde amphibolite-facies event. A second textural type of titanite forms anhedral grains with plagioclase and pargasite, which is developed where the retrograde amphibolite-facies assemblage overprints the eclogite mineralogy. U–Pb dating has yielded the following ages: zircon age of 995 ± 8 Ma, and variably discordant rutile ages between 416 and 480 Ma. U–Pb and Pb–Pb isochrons on titanite and plagioclase/quartz separates yielded ages of 971 ± 65 Ma and 945 ± 57 Ma, respectively, in agreement with the zircon age. Analysed zircons and titanites are texturally part of the amphibolite-facies assemblage. The new zircon age demonstrates that amphibolite-facies metamorphism during exhumation occurred at 995 ± 8 Ma; the titanites could have closed with respect to Pb at this time or alternatively at some time between
c
. 1000 and 900 Ma. These data clearly demonstrate that parts of the Scottish basement underwent major thick-skinned tectonics during the Grenvillian orogeny. Rutile is part of the eclogite-facies paragenesis, and yet has young ages; these data are best explained by reheating producing near-total Pb loss related to emplacement of the late- to post-tectonic Ratagain Granite Complex at
c
. 425 Ma, at the end of the Caledonian orogeny.
High-temperature crustal anatexis in a clockwise
P
–
T
–
t
path: isotopic evidence from a granulite–granitoid suite in the Eastern Ghats belt, India
Authors: Bhattacharya S. , Kar Rajib , Teixeira W. , Basei M.
Published: December 2007

The high-grade metamorphic belt of the Eastern Ghats, India, displays polyphase deformation structures, a complex metamorphic record and dehydration melting in different crustal protoliths. High-temperature melting in pelitic and greywacke-like precursors in a clockwise
P
–
T
path, decompression and subsequent isobaric cooling have recently been described from the south–central sector of this belt. In this contribution, high-temperature melting has been dated at
c
. 1162 Ma by Sm–Nd whole-rock isotopic compositions of granitoids. Subsequent isobaric cooling could have occurred between 988 and 900 Ma as indicated by U–Pb ages of zircon and monazite in pelitic granulites. Thus, a prolonged orogenic cycle of at least 250 Ma is envisaged. Additionally, isotopic disequilibrium between whole rock and minerals in sapphirine granulites could have resulted from rapid melting and been further enhanced by a prolonged reaction history of the sapphirine granulite.
Evolution and volcanic hazards of Taapaca Volcanic Complex, Central Andes of Northern Chile
Authors: Clavero J.E. , Sparks R.S.J. , Pringle M.S. , Polanco E. , Gardeweg M.C.
Published: December 2007

Taapaca Volcanic Complex is a large dacitic volcano (35 km
3
) located in the western border of the active zone of the Central Andes of Northern Chile. Apart from early poorly preserved silicic andesites, Taapaca Volcanic Complex has generated remarkably similar porphyritic hornblende–biotite dacites with distinctive sanidine megacrysts for at least 1.5 Ma. The main products of the volcano are dacite lavas and domes with associated block-and-ash flow deposits. There have also been several sector collapses to generate debris avalanches, which are closely associated with volcanic blasts and episodes of dome growth. Four stages of evolution are recognized with volcanism occurring in short bursts between much longer periods of dormancy. Volcanism has built a substantial stratovolcano and has migrated 4–5 km towards the SW with time. Late Pleistocene to Holocene activity has involved at least three sector collapses of the hydrothermally altered flanks and domes. Volcanic blasts, block-and-ash flows, debris avalanches and lahars have been distributed down the southwestern flanks. These areas are the main populated part of the Chilean Altiplano and the location of the main road between Bolivia and the Pacific Ocean coast. A future eruption will threaten these areas and the regional economy.
The structural and diagenetic evolution of injected sandstones: examples from the Kimmeridgian of NE Scotland
Authors: Jonk R. , Duranti D. , Parnell J. , Hurst A. , Fallick A.E.
Published: December 2007

Injected sandstones occurring in the Kimmeridgian of NE Scotland along the bounding Great Glen and Helmsdale faults formed when basinal fluids moved upward along the fault zones, fluidizing Oxfordian sands encountered at shallow depth and injecting them into overlying Kimmeridgian strata. The orientation of dykes, in addition to coeval faults and fractures, was controlled by a stress state related to dextral strike-slip along the bounding fault zones. Diagenetic studies of cements allow the reconstruction of the fluid flow history. The origin of deformation bands in sandstone dykes and sills was related to the contraction of the host-rocks against dyke and sill walls following the initial stage of fluidized flow, and these deformation bands are the earliest diagenetic imprint. Early non-ferroan calcite precipitated in injection structures at temperatures between 70 and 100 °C, indicating that it precipitated from relatively hot basinal fluids that drove injection. Coeval calcite-filled fractures show similar temperatures, suggesting that relatively hot fluids were responsible for calcite precipitation in any permeable pathway created by dextral simple shear along the faults. During progressive burial, percolating sea water was responsible for completely cementing the still relatively porous injected sandstones with a second generation of ferroan calcite, which contains fluid inclusions with homogenization temperatures below 50 °C. During this phase, depositional host sandstones were also cemented.
Architectural styles of prograding wedges in a tectonically active setting, Crotone Basin, Southern Italy
Authors: Zecchin Massimo , Massari Francesco , Mellere Donatella , Prosser Giacomo
Published: December 2007

The lower Pliocene shallow-marine to continental succession of the Crotone Basin, a small forearc basin on the Calabrian Arc, Southern Italy, is represented by a mixed terrigenous–carbonate succession, up to 850 m thick, known as the Zinga Molasse, deposited in an active tectonic setting dominated by extensional structures and halokinesis. The succession may be informally subdivided into three main sequences, Zinga 1, Zinga 2, Zinga 3, each bounded by major unconformities produced by the interaction of tectonics and eustasy. The Zinga 1 sequence records terrigenous input into the basin leading to the development of stacked progradational wedges of shoreface and deltaic deposits. Spectacular thickness changes and progressive unconformities result from the activation of NE-trending growth folds and listric faults, and indicate that deposition occurred during extensional deformation and salt tectonics. However, the regional extent of the surfaces, the lack of evidence for changes in the local tectonic regime between sequences and the presence of listric faulting within sequences all favour eustatic sea-level change as the main control on the sequence development, although local tectonics strongly controlled sedimentary architecture.
Early Palaeozoic near-surface deformation in the Neptune Range, Antarctica: implications for the Ross and Gondwanian orogenies
Authors: Curtis M.L. , Storey B.C.
Published: December 2007

The Neptune Range of the Pensacola Mountains, East Antarctica, exposes a record of Early Palaeozoic to Early Mesozoic polyphase deformation along the former East Antarctic margin of Gondwana that is unique within the 3500 km length of the Transantarctic Mountains. The earliest of these orogenic events is the polyphase Early Palaeozoic Ross orogeny. Following two phases of intense pre-late Mid-Cambrian deformation (D
1
and D
2
), a succession of volcanic and sedimentary rocks (sequences 2 and 3) were deposited in late Mid- to Late Cambrian time during a transient period of back-arc rifting. New stratigraphical and structural relationships suggest that the Cambrian succession was deformed during latest Cambrian time while at or near the palaeosurface in a foreland basin setting (D
3
). D
3
deformation is characterized by thrust faulting and folding without the development of a widespread coeval cleavage, with evidence for syntectonic deposition of the basal Neptune Group (sequence 4). The main regional cleavage developed through the Palaeozoic cover rocks (sequences 2–5) is also developed in rare Permo-Carboniferous clastic dykes that cut down through the stratigraphy from the base of the Gale Mudstone. The dyke–cleavage relationship, together with observations of the conglomerate cobbles from throughout the stratigraphical succession, suggests that the most intense deformation within the Cambrian sequences is Permo-Triassic (Gondwanian orogeny) rather than latest Cambrian (late Ross orogeny) as previously concluded. Our data corroborate recent suggestions that the main phase of Ross orogenic deformation is pre-late Mid-Cambrian and not Late Cambrian or Early Ordovician.
Cavalli Seamount, Northland Plateau, SW Pacific Ocean: a Miocene metamorphic core complex?
Authors: Mortimer N. , Herzer R.H. , Walker N.W. , Calvert A.T. , Seward D. , Chaproniere G.C.H.
Published: December 2007

Cavalli Seamount (34°06′S, 174°10′E) is an irregular-shaped, flat-topped seamount on the Northland Plateau, SW Pacific Ocean. In contrast to Miocene lavas recovered from other seamounts in the area, the rocks dredged from Cavalli Seamount consist of biotite schist, with minor calc-silicate bands. Mineralogy, whole-rock chemistry, U–Pb dating of detrital zircons, and Sr and Nd isotopic composition collectively indicate a siliciclastic–carbonate protolith of latest Cretaceous to Paleogene stratigraphic age. Metamorphic index minerals are sillimanite, andesine, garnet, ilmenite and K-feldspar, and indicate peak
P
–
T
conditions of
c
. 650 °C and
c
. 0.4 GPa. U–Pb, Ar/Ar and fission-track dating of minerals, and micropalaeontological dating of associated limestones, indicate rapid cooling in the interval 23–21 Ma. The schist contains chloritized and hematized slickenslides parallel to a penetrative lineation, s–c planes and conjugate microfractures, and has limestone geopetal infillings parallel to foliation. These features are consistent with the interpretation of Cavalli Seamount as part of the lower plate of an Early Miocene metamorphic core complex. Although other explanations are possible, the core complex interpretation fits with regional Early Miocene events including crustal thickening as a result of allochthon emplacement in northern New Zealand, crustal thinning associated with rapid extension in the South Fiji Basin, Pacific trench rollback, and abundant Early Miocene igneous activity.
Uplift and slip rates of the eastern Eliki fault segment, Gulf of Corinth, Greece, inferred from Holocene and Pleistocene terraces
Authors: McNeill L.C. , Collier R.E.Ll.
Published: December 2007

Uplifted Pleistocene and Holocene marine and fluvial deposits are preserved in the footwall of the Eliki fault, western Gulf of the Corinth, where geodetic extension rates exceed 10 mm a
−1
. Up to 10 Pleistocene terraces are distinguished in the footwall block of the eastern Eliki fault segment, discontinuously preserved along strike. Terraces are depositional, forming by the progradation of clastic fan deltas, or predominantly erosional, between fan deltas. Correlation of terrace profiles with Late Pleistocene eustatic sea level suggests an uplift rate of
c
. 1 mm a
−1
, with an alternative of
c
. 1.5 mm a
−1
. On average, higher rates are obtained from uplifted Holocene deposits (
c
. 1–2 mm a
−1
). To determine slip rates, a long-term ratio of uplift to subsidence of
c
. 1:2–3.2, derived from net footwall altitude and basin subsidence–fill and a fault dip of 50° are applied to uplift of
c
. 1 mm a
−1
. These produce a slip rate of
c
. 4–7 mm a
−1
contributing
c
. 2–4 mm a
−1
to extension across the Gulf, significantly less than geodetic rates. This discrepancy may result from strain taken up on faults to the north and offshore. Uplift rates decrease little at the Eliki fault tips. Uplift rates are broadly consistent in the central–western Gulf but show a decrease in average uplift from Corinth eastward.
Extreme crustal thinning in the south Porcupine Basin and the nature of the Porcupine Median High: implications for the formation of non-volcanic rifted margins
Authors: Reston T.J. , Gaw V. , Pennell J. , Klaeschen D. , Stubenrauch A. , Walker I.
Published: December 2007

The southern Porcupine Basin is characterized by axial stretching factors that are greater than six and typical of rifted margins. As such, the basin can be regarded as a natural laboratory to investigate the evolution and symmetry of rifting leading towards continental separation and breakup. A bright reflection (here named P) cuts down to the west from the base of the sedimentary section, is overlain by small fault blocks and appears to represent a detachment fault. P may in part follow the top of partially serpentinized mantle: this interpretation is consistent with gravity modelling, and with numerical models of crustal embrittlement and mantle serpentinization during extension. Furthermore, P closely resembles the S reflection west of Iberia, where such serpentinites are well documented. Although overall the basin remains symmetrical, the consistent westward structural dip of the detachment implies that, at high stretching factors, extension became asymmetric. Farther south, the ‘Porcupine Median High’, appearing lens-shaped in cross-section, overlies the tilted fault blocks and is onlapped by postrift sediment. Despite no evidence for synrift magmatism, this high has previously been interpreted as a basaltic structure. However, it develops above the line of intersection of the crust–mantle boundary with the P detachment, and hence may be related to the spatial limit of serpentinization. The median high may represent a serpentinite mud volcano or diapir; we suggest that such structures produce the serpentinite breccias found within the rifted continent–ocean transition of nonvolcanic margins.
U–Pb geochronology of the Leknes Group: an exotic Early Caledonian metasedimentary assemblage stranded on Lofoten basement, northern Norway
Authors: Corfu F.
Published: December 2007

The Leknes Group is an amphibolite-facies metasedimentary assemblage thrust onto the Palaeoproterozoic basement of the Lofoten islands west of the Caledonian chain in northern Norway. Its genesis has been enigmatic, and both Sveconorwegian and Silurian ages of metamorphism have been proposed. U–Pb dating now shows that the main metamorphic and structural overprints occurred in the Mid-Ordovician, between the 469 ± 3 Ma age of a metatonalite and the 461 ± 1 Ma age of a titanite crystal co-planar with the main fabric. According to the prevalent structural interpretation this age also dates thrusting of the Leknes Group onto the Lofoten basement. Zircon and rutile in mica schists record this as well as a younger event of zircon growth at 412 ± 2 Ma, the latter coinciding with early stages of extension and enhanced fluid activity; in southern Lofoten this is also associated with the intrusion of 410 ± 3 Ma pegmatites. The Leknes Group shows an affinity with some terranes of peri-Baltican affinity in the Upper Allochthon of the Caledonides. It probably developed in a marginal basin close to Sveconorwegian basement, as shown by detrital zircon ages and published Nd isotopic data, before being thrust onto the Lofoten basement, which appears to be itself a late Caledonian allochthonous terrane.
Volcanism, CO
2
and palaeoclimate: a Late Jurassic–Early Cretaceous carbon and oxygen isotope record
Authors: Weissert Helmut , Erba Elisabetta
Published: December 2007

A composite Tethyan Late Jurassic–Early Cretaceous carbon and oxygen isotope curve is presented. C-isotope data provide information on the evolution and perturbation of the global carbon cycle. O-isotope data are used as a palaeotemperature proxy in combination with palaeontological information. The resulting trends in climate and in palaeoceanography are compared with biocalcification trends and oceanographic conditions favouring or inhibiting biocalcification. Positive C-isotope anomalies in the Valanginian and Aptian correlate with episodes of increased volcanic activity regarded as a source of excess atmospheric carbon dioxide. A major warming pulse accompanies the Aptian but not the Valanginian C-isotope event. The observed change in Early Aptian temperatures could have triggered the destabilization of sedimentary gas hydrates and the sudden release of methane to the biosphere as recorded as a distinct negative carbon isotope pulse preceding the positive excursion. Both C-isotope anomalies are accompanied by biocalcification crises that may have been triggered by
p
CO
2
-induced changes in climate and in surface water chemistry. Elevated nutrient levels in river-influenced coastal waters and in upwelling regions further weakened marine calcification. These conditions contrast with ‘normal’ trophic conditions prevailing in the latest Jurassic and favouring biocalcification. The C- and O-isotope curves record a stable mode of carbon cycling and stable temperatures. We conclude that biocalcification is mostly triggered (and inhibited) by CO
2
conditions in the atmosphere–ocean system.