Mesoproterozoic differential metasomatism in subcontinental lithospheric mantle of Central Indian Tectonic zone: Evidence from major and trace element geochemistry of padhar mafic-ultramafic complex     

Kasturi Chakraborty  Abhinaba Roy 《Journal of the Geological Society of India》2012,80(5):628-640

Metasomatism above subduction zone is an important process capable of producing a heterogeneous mantle wedge with locally varying characters. This, in turn, leads to variation in character of the mafic and intermediate rocks produced through partial melting of lithospheric mantle. The Padhar mafic-ultramafic complex is situated in western part of the Betul belt, Central India, shows enrichment in Rb, Ba, Th and Pb and depletion in Nb, Hf and Zr. Major and trace element data along with REE, confirms the presence of a metasomatized mantle above a Mesoproterozoic subduction zone. Differential petrological evolution, corresponding to the different magma batches, as reflected in almost all of the binary element / oxide variation diagrams, testifies small scale metasomatic heterogeneity in the underlying suprasubduction zone mantle wedge.  相似文献   

Textural characterization, major and volatile element quantification and Ar–Ar systematics of spherulites in the Rocche Rosse obsidian flow, Lipari, Aeolian Islands: a temperature continuum growth model     

P. L. Clay  B. O’Driscoll  R. Gertisser  H. Busemann  S. C. Sherlock  S. P. Kelley 《Contributions to Mineralogy and Petrology》2013,165(2):373-395

Spherulitic textures in the Rocche Rosse obsidian flow (Lipari, Aeolian Islands, Italy) have been characterized through petrographic, crystal size distribution (CSD) and in situ major and volatile elemental analyses to assess the mode, temperature and timescales of spherulite formation. Bulk glass chemistry and spherulite chemistry analyzed along transects across the spherulite growth front/glass boundary reveal major-oxide and volatile (H₂O, CO₂, F, Cl and S) chemical variations and heterogeneities at a ≤5 μm scale. Numerous bulk volatile data in non-vesicular glass (spatially removed from spherulitic textures) reveal homogenous distributions of volatile concentrations: H₂O (0.089 ± 0.012 wt%), F (950 ± 40 ppm) and Cl (4,100 ± 330 ppm), with CO₂ and S consistently below detection limits suggesting either complete degassing of these volatiles or an originally volatile-poor melt. Volatile concentrations across the spherulite boundary and within the spherulitic textures are highly variable. These observations are consistent with diffusive expulsion of volatiles into melt, leaving a volatile-poor rim advancing ahead of anhydrous crystallite growth, which is envisaged to have had a pronounced effect on spherulite crystallization dynamics. Argon concentrations dissolved in the glass and spherulites differ by a factor of ~20, with Ar sequestered preferentially in the glass phase. Petrographic observation, CSD analysis, volatile and Ar data as well as diffusion modeling support continuous spherulite nucleation and growth starting at magmatic (emplacement) temperatures of ~790–825 °C and progressing through the glass transition temperature range (T _g ~ 750–620 °C), being further modified in the solid state. We propose that nucleation and growth rate are isothermally constant, but vary between differing stages of spherulite growth with continued cooling from magmatic temperatures, such that there is an evolution from a high to a low rate of crystallization and low to high crystal nucleation. Based on the diffusion of H₂O across these temperature ranges (~800–300 °C), timescales of spherulite crystallization occur on a timescale of ~4 days with further modification up to ~400 years (growth is prohibitively slow <400 °C and would become diffusion reliant). Selective deformation of spherulites supports a down-temperature continuum of spherulite formation in the Rocche Rosse obsidian; indeed, petrographic evidence suggests that high-strain zones may have catalyzed progressive nucleation and growth of further generations of spherulites during syn- and post-emplacement cooling.  相似文献   

Tracking Fishes With a Microwatt Acoustical Receiver —An Archival Tag Development     

Godi Fischer Sangmok Lee Michael Obara Prasan Kasturi H. Thomas Rossby Conrad W. Recksiek 《Oceanic Engineering, IEEE Journal of》2006,31(4):975-985

This paper presents the design of an ultralow-power acoustical receiver circuit intended to track small aquatic animals. The receiver forms a crucial component of a versatile data logger capable of sensing and storing a variety of biologically important data such as geographic position, ambient temperature, pressure, etc. The size of the final tag will be determined by the size of the cylindrical hydrophone, which will serve as housing for all electronic components, the external sensors, the timing crystal, and the battery. The receiver circuit was prototyped on a 0.5-mum complementary metal-oxide-semiconductor (CMOS) chip. Extensive lab tests proved all system component functional. The fully operational receiver consumes 21 muW at 3 V. Results from a preliminary field test, conducted with a source generating a sound pressure level of 180 dB re 1 muPa, predict a tracking range of 100-120 km  相似文献   

Oogenesis and fecundity of haddock (Melanogrammus aeglefinus L.) from the Nova Scotia shelf     

Clay  Douglas 《ICES Journal of Marine Science》1989,46(1):24-34

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RoboNet‐II: Follow‐up observations of microlensing events with a robotic network of telescopes     

Y. Tsapras  R. Street  K. Horne  C. Snodgrass  M. Dominik  A. Allan  I. Steele  D.M. Bramich  E.S. Saunders  N. Rattenbury  C. Mottram  S. Fraser  N. Clay  M. Burgdorf  M. Bode  T.A. Lister  E. Hawkins  J.P. Beaulieu  P. Fouqu  M. Albrow  J. Menzies  A. Cassan  D. Dominis‐Prester 《Astronomische Nachrichten》2009,330(1):4-11

RoboNet‐II uses a global network of robotic telescopes to perform follow‐up observations of microlensing events in the Galactic Bulge. The current network consists of three 2 m telescopes located in Hawaii and Australia (owned by Las Cumbres Observatory) and the Canary Islands (owned by Liverpool John Moores University). In future years the network will be expanded by deploying clusters of 1 m telescopes in other suitable locations. A principal scientific aim of the RoboNet‐II project is the detection of cool extra‐solar planets by the method of gravitational microlensing. These detections will provide crucial constraints to models of planetary formation and orbital migration. RoboNet‐II acts in coordination with the PLANET microlensing follow‐up network and uses an optimization algorithm (“web‐PLOP”) to select the targets and a distributed scheduling paradigm (eSTAR) to execute the observations. Continuous automated assessment of the observations and anomaly detection is provided by the ARTEMiS system (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

An RTML transport implementation on the Liverpool Telescope     

N.R. Clay 《Astronomische Nachrichten》2008,329(3):314-316

The Liverpool Telescope is a 2.0m fully robotic telescope based on the Canary island of LaPalma. In this paper I describe the Java(TM) implementation of a method to transport RTML (Remote Telescope Markup Language) between a Node Agent (Web Services endpoint) embedded at the telescope and a remote Agent. The advantages and disadvantages of the method are discussed, along with the suitability of the protocol for HTN standardisation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Geophysical identification of unmarked historic graves     

Rinita A. Dalan  Steven L. De Vore  R. Berle Clay 《Geoarchaeology》2010,25(5):572-601

Down‐hole magnetic susceptibility techniques were explored as a means of improving near‐surface geophysical surveys in historic grave detection. These techniques were used to document distinctive magnetic characteristics of grave shafts at three historic cemeteries first surveyed using various near‐surface geophysical methods. Tests revealed a low magnetic susceptibility signature that soil magnetic studies indicated was largely related to differential soil compaction associated with the excavation and refilling of grave shafts. Most apparent at depths beyond those reached by soil penetrometers, this magnetic signature offers a way to assess anomalies identified by near‐surface techniques that potentially represent graves. At one cemetery, magnetic studies of the interments themselves suggested spatially patterned, magnetically enhanced zones that might also aid in burial identification in certain contexts. While down‐hole techniques will not be foolproof, they do provide another geophysical tool that can be used to improve grave detection. © 2010 Wiley Periodicals, Inc.  相似文献   

Modified predictor–corrector numerical scheme for real‐time pseudo dynamic tests using state‐space formulation     

Yunfeng Zhang  Richard Sause  James M. Ricles  Clay J. Naito 《地震工程与结构动力学》2005,34(3):271-288

This paper deals with an explicit numerical integration method for real‐time pseudo dynamic tests. The proposed method, termed the MPC‐SSP method, is suited to use in real‐time pseudo dynamic tests as no iteration steps are involved in each step of computation. A procedure for implementing the proposed method in real‐time pseudo dynamic tests is described in the paper. A state‐space approach is employed in this study to formulate the equations of motion of the system, which is advantageous in real‐time pseudo dynamic testing of structures with active control devices since most structural control problems are formulated in state space. A stability and accuracy analysis of the proposed method was performed based on linear elastic systems. Owing to an extrapolation scheme employed to predict the system's future response, the MPC‐SSP method is conditionally stable. To demonstrate the effectiveness of the MPC‐SSP method, a series of numerical simulations were performed and the performance of the MPC‐SSP method was compared with other pseudo dynamic testing methods including Explicit Newmark, Central Difference, Operator Splitting, and OS‐SSP methods based on both linear and non‐linear single‐degree‐of‐freedom systems. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Phosphorus Sorption and Availability from Biochars and Soil/Biochar Mixtures   总被引：2，自引：0，他引：2       下载免费PDF全文

Rajesh Chintala  Thomas E. Schumacher  Louis M. McDonald  David E. Clay  Douglas D. Malo  Sharon K. Papiernik  Sharon A. Clay  James L. Julson 《洁净——土壤、空气、水》2014,42(5):626-634

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A protocol standard for heterogeneous telescope networks     

A. Allan  F. Hessman  K. Bischoff  M. Burgdorf  B. Cavanagh  D. Christian  N. Clay  R. Dickens  F. Economou  M. Fadavi  S. Fraser  T. Granzer  S. Grosvenor  T. Jenness  A. Koratkar  M. Lehner  C. Mottram  T. Naylor  E. Saunders  N. Solomos  I. Steele  G. Tuparev  T. Vestrand  R. White  S. Yost 《Astronomische Nachrichten》2006,327(8):744-750

The scientific need for a standard protocol permitting the exchange of generic observing services is rapidly escalating as more observatories adopt service observing as a standard operating mode and as more remote or robotic telescopes are brought on‐line. To respond to this need, we present the results of the first interoperability workshop for Heterogeneous Telescope Networks (HTN) held in Exeter. We present a draft protocol, designed to be independent of the specific instrumentation and software that controls the remote and/or robotic telescopes, allowing these telescopes to appear to the user with a unified interface despite any underlying architectural differences. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献