The ∼860-Ma, cordilleran-type guandaoshan dioritic pluton in the Yangtze Block, SW China: Implications for the origin of neoproterozoic magmatism

The tectonic setting of the widespread Neoproterozoic igneous rocks in South China has long been a matter of debate. Situated in the western margin of the Yangtze Block of South China, the Guandaoshan pluton is composed of diorite in the core and quartz diorite in the margin. Both types contain abundant mafic enclaves and mafic dikes. This pluton is dated at 858 ± 7 Ma by the SHRIMP zircon U-Pb method. The rocks have SiO 2 contents of 52.8-63.8 wt%, Al 2O 3 contents of 17.4-20.6 wt%, Na 2O contents of 2.14-3.74 wt%, and K 2O contents of 0.44-1.61 wt%. They are calcalkaline with an Al saturation index, A/CNK 1, and they have Fe numbers <0.8 (Fe 2O 3/[Fe 2O 3 + MgO]). Their total rare earth element (REE) contents range from 19 to 45 ppm, with concave chondrite-normalized patterns slightly depleted in middle REEs, indicating extensive amphibole fractionation. Their whole-rock ε Nd(t) values range from +3.9 to +5.1, and initial 87Sr/ 86Sr ratios range from 0.7028 to 0.7033. They have zircon ε Hf(t) values ranging from +11 to +17, with mean Hf model ages of around 860 Ma, clearly indicating a depleted-mantle source. In the primitive mantle-normalized trace element spider diagram, the rocks show pronounced enrichment of Rb, Ba, Th, and Pb and depletion of Nb, Ta, and Ti, a typical arc signature. The Guandaoshan pluton is an amphibole-rich, calc-alkaline, Cordilleran-type granitoid, a typical product of subduction-zone magmatism. The occurrence of this Neoproterozoic Cordilleran-type granitoid suggests that the western margin of the Yangtze Block was an Andean-type continental margin at that time, rather than mantle plume-related rifting setting. © 2008 by The University of Chicago. All rights reserved.published_or_final_versio

Investigating properties of the cardiovascular system using innovative analysis algorithms based on ensemble empirical mode decomposition

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited - Copyright @ 2012 Jia-Rong Yeh et al.Cardiovascular system is known to be nonlinear and nonstationary. Traditional linear assessments algorithms of arterial stiffness and systemic resistance of cardiac system accompany the problem of nonstationary or inconvenience in practical applications. In this pilot study, two new assessment methods were developed: the first is ensemble empirical mode decomposition based reflection index (EEMD-RI) while the second is based on the phase shift between ECG and BP on cardiac oscillation. Both methods utilise the EEMD algorithm which is suitable for nonlinear and nonstationary systems. These methods were used to investigate the properties of arterial stiffness and systemic resistance for a pig's cardiovascular system via ECG and blood pressure (BP). This experiment simulated a sequence of continuous changes of blood pressure arising from steady condition to high blood pressure by clamping the artery and an inverse by relaxing the artery. As a hypothesis, the arterial stiffness and systemic resistance should vary with the blood pressure due to clamping and relaxing the artery. The results show statistically significant correlations between BP, EEMD-based RI, and the phase shift between ECG and BP on cardiac oscillation. The two assessments results demonstrate the merits of the EEMD for signal analysis.This work is supported by the National Science Council (NSC) of Taiwan (Grant number NSC 99-2221-E-155-046-MY3), Centre for Dynamical Biomarkers and Translational Medicine, National Central University, Taiwan which is sponsored by National Science Council (Grant number: NSC 100–2911-I-008-001) and the Chung-Shan Institute of Science & Technology in Taiwan (Grant numbers: CSIST-095-V101 and CSIST-095-V102)

Detection of dynamic rhythms of electroencephalography by using wavelet packets decomposition

Wavelet packet decomposition is used to investigate. the time-varying characteristics of clinical EEG signals. On the basis of the nonstationary nature of clinical EEG rhythms, wavelet packet analysis is employed for designing filters with different frequency characteristics to detect 4 kinds of EEG rhythms. The coefficients of wavelet transformation corresponding to the rhythms are used to form the dynamic brain electrical activity mapping (DBEAM). In order to understand the dynamic rhythms of the EEG, some clinical EEG are analyzed and compared. It is indicated from the experimental results that the dynamic characteristics of clinical brain electrical activities can be provided in terms of wavelet packet decomposition.published_or_final_versio

A method for estimating the instantaneous frequency of non-stationary heart sound signals

Practical signals such as speech, biomedical measurement and communications turn out to be extremely non-stationary and nonlinear time series. Traditional FFT-based power spectral analysis fails to deal with these transient signals. To provide more efficient way for investigating non-stationary and nonlinear signals with high time-frequency resolution and extract more information regarding the transient frequency features involved in the signals, a novel method based on the instantaneous frequency distribution is developed in this paper to provide the time-frequency distribution of the practical signals. The aim of this contribution is to explore the role that both empirical mode decomposition and Hilbert transform can be used to play in such practical signals. Both simulation and experimental results were presented and analyzed to demonstrate the power and effectiveness of the proposed new time-frequency distribution.published_or_final_versio

Tectonic background of the Kuda ophiolite, western Kunlun: new constraints from boninite series rocks

通过对依莎克群火山岩的地球化学研究，首次在西昆仑库地蛇绿岩中发现了玻安岩系岩石。这些岩石具有高SiO2、低TiO2、高Al2O3/TiO2 比值和高Cr 含量，亏损Y 和REE，呈现轻稀土富集的分布模式以及相对低的Ti/Zr 比值和高的Zr/Y 比值。其中一些样品还具有相当于MORB 的Nb、Ta 含量和相应较小的La/Nb 比值，表明在其形成过程中可能有富集地幔端员的介入。玻安岩系岩石的发现以及火山地层序列的岩性变化表明，依莎克群火山岩形成于初始的大洋岛弧或弧后盆地拉张的早期阶段，火山岩的地球化学组成变化以及玻安岩在依莎克群火山序列中的位置表明，原特提斯的消减方向应当是向北的。Preliminary geochemical study is conducted for the Yishake volcanic sequence of Küda ophiolote, West Kunlun, and boninite series rocks are just recognized for the first time in this area. The boninite series rocks are characterized by relatively high SiO2 and Cr, high Al2O3/TiO2 ratios and being very depleted in TiO2, Y and REE. They all exhibit LREE enriched patterns and show low Ti/Zr and high Zr/Y ratios. Some of these samples possess relatively high Nb and Ta contents equivalent to those of MORB and accordingly low …published_or_final_versio

Determination of elastic and viscoplastic material properties obtained from indentation tests using a combined finite element analysis and optimization approach

Conventional indentation tests do not provide an accurate estimation of viscoplastic material properties. In this work, a combined finite element analysis and optimization approach is developed for the determination of elastic–plastic and creep material properties using only a single indentation loading–unloading curve based on a two-layer viscoplasticity model. Utilizing the indentation loading–unloading curve obtained from a finite element-simulated experiment with a spherical and a conical indenter, a set of six key material properties (Young’s modulus, yield stress, work hardening exponent and three creep parameters) can be determined. Non-linear optimization algorithms are used with different sets of initial material properties, leading to good agreements with the numerically simulated target loading–unloading curves

Provenance and tectonic setting of the Neoproterozoic Yanbian Group, western Yangtze Block (SW China)

Tectonic evolution of the Yangtze Block of South China during Neoproterozoic time has been a major focus of debate and is important in the reconstruction of the Rodinian supercontinent. The Yanbian Group in the western margin of the Yangtze Block is a well-preserved Neoproterozoic volcanic-sedimentary sequence and provides a rare opportunity to examine the provenance and tectonic setting. It consists of a lower part composed of ∼1500 m thick basaltic lavas and an upper part of ∼3500 m thick flysch deposits. The flysch sequence contains typical deep marine turbidites consisting mainly of fine-grained volcaniclastic sandstones and mudstones, indicating a submarine fan depositional system. Detrital zircon dating yields ages ranging from ca. 865 Ma to 1000 Ma with two peaks at ca. 900 Ma and 920 Ma, respectively. The Yanbian Group is intruded by the ∼860 Ma Guandaoshan dioritic pluton, constraining its depositional age at ca. 870 Ma. The sandstones contain abundant feldspar and lithic fragments with minor amounts of quartz and have an average composition of Q 16F 35L 49, suggesting a proximal source and an undissected to transitional arc setting. The lithic fragments in the sandstones point to andesitic and felsic volcanic rock sources. The sandstones and mudstones have intermediate SiO 2/Al 2O 3 (typically 3-6), high Fe 2O 3 + MgO contents (5-12 wt%), and moderate to high K 2O/Na 2O ratios (generally 0.1-1 and 1-10 for sandstones and mudstones, respectively). In comparison with average upper continental crust, they show strong negative Nb-Ta anomalies, slight depletion of Zr-Hf, La and Th, but moderate enrichment of V, Cr, Ni, and Sc. These rocks show LREE enrichment (La/Yb N = 5.3-7.4) with flat HREE, and pronounced negative Eu anomalies (Eu/Eu * = 0.6-0.74) in chondrite-normalized REE patterns, similar to post-Archean shales. Geochemical data for these rocks suggest an arc setting and intermediate-felsic volcanic source, consistent with a back-arc basin scenario for the basaltic lavas in the lower Yanbian Group. Together with regional geological evidence, the turbidites of the Yanbian Group strongly support a model in which the western margin of the Yangtze Block was a major magmatic arc, active probably from ∼920 Ma to 740 Ma, a period of more than 180 million years. © 2008 Elsevier B.V. All rights reserved.postprin

Geochemistry and petrogenesis of the Yishak Volcanic Sequence, Kudi ophiolite, West Kunlun (NW China): Implications for the magmatic evolution in a subduction zone environment

The Yishak Volcanic Series (YVS) is part of the Late Cambrian Kudi ophiolite in the western Kunlun Mountains, NW China, which marks the oldest suture zone in the Tibetan Plateau. The YVS is a well-preserved sequence comprising five conformable units (A to E) of basalts to andesites, with mafic dykes in Units A to D. These rocks are sequentially characterized upward by geochemical features of N-MORB (Unit A), E-MORB (Unit B), island-arc basalt (Unit C), BABB (Unit D and mafic dykes) and boninite series rocks (Unit E), reflecting complex interactions among various source components. The evolution of magma compositions from MORB-dominated to boninite series rocks clearly indicates temporally increasing subduction signatures, which, in combination with the extensional tectonic background, suggests that the Kudi ophiolite most likely formed in a spontaneous nucleation of subduction zone. © Springer-Verlag 2005.postprin

Highly heterogeneous Late Mesozoic lithospheric mantle beneath the North China Craton: evidence from Sr–Nd–Pb isotopic systematics of mafic igneous rocks

The lithospheric mantle beneath the North China Craton changed dramatically in its geophysical and geochemical characteristics from Palaeozoic to Cenozoic times. This study uses samples of Mesozoic basalts and mafic intrusions from the North China Craton to investigate the nature of this mantle in Mesozoic times. Sr-Nd-Pb isotopic data demonstrate that the Late Mesozoic lithospheric mantle was extremely heterogeneous. In the central craton or the Luzhong region, it is slightly Sr-Nd isotopically enriched, beneath the Taihangshan region it has an EMI character (87Sr/86Sri = 0.7050-0.7066; εNd = -17--10), and beneath the Luxi-Jiaodong region, it possesses EM2-like characteristics (87Sr/86Sri up to 0.7114). Compositional variation with time is also apparent in the Mesozoic lithospheric mantle. Our data suggest that the old lithospheric mantle was modified during Mesozoic times by a silicic melt, where beneath the Luxi-Jiaodong region it was severely modified, but in the Luzhong and Taihangshan regions the effects were much less marked. The silicic melt may have been the product of partial melting of crustal materials brought into the mantle by the subducted slab during the formation of circum-cratonic orogenic belts. This Mesozoic mantle did not survive for a long time, and was replaced by a Cenozoic mantle with depleted geochemical characteristics. © 2004 Cambridge University Press.published_or_final_versio

SandBOX: An intuitive conceptual design system

We describe the development and use of a new conceptual design system, called SandBOX, which combines a range of intuitive interfaces with real-time analysis, thus enabling a wide variety of users to develop performative concept designs. We show how this interactive design platform can overcome some of the limitations of current physical model-based design processes, whilst retaining many of their advantages