Neoproterozoic mafic-ultramafic layered intrusion in Quruqtagh of northeastern Tarim Block,NW China: Two phases of mafic igneous activity with different mantle sources     

Chuan-Lin Zhang  Dong-Sheng Yang  Hong-Yan Wang  Yutaka Takahashi  Hai-Min Ye 《Gondwana Research》2011,19(1):177-190

In this paper we report zircon U–Pb age, chemical compositions of rock-forming minerals, and whole-rock elemental and Sr–Nd isotopic data for the No. II mafic-ultramafic intrusive complex (N2MC) in the Quruqtagh area at the northeastern margin of the Tarim Block, northwestern China to evaluate its petrogenesis and tectonic significance. The N2MC with an exposure area of ca. 12 km² has a funnel-shaped cross-section and intruded the Paleoproterozoic basement. U–Pb zircon dating gives a crystallization age of 760 ± 6 Ma. Rock types of the N2MC include lherzolite, pyroxenite, gabbro and minor diorite. Major elements geochemistry of these rocks exhibits a tholeiitic trend with a wide range of SiO₂ contents (38.8–60 wt.%). On the other hand, they are systematically enriched in LILE, LREE and depleted in HFSE and HREE, thus leading to low HFSE/LREE ratios (e.g., Nb/La ≈ 0.3). Isotopically, the studied rocks are characterized by negative whole-rock εNd(t) values (? 7.6 to ? 2.8) and variable high (⁸⁷Sr/⁸⁶Sr)_i (0.7095–0.7059). These features, together with chemical compositions of the rock-forming minerals and the presence of the primary phlogopite and hornblende, suggest that N2MC was likely formed via crystal fractionation/cumulation (with negligible crustal contamination) of a tholeiitic magma derived from a metasomatized subcontinental lithosphere mantle (SCLM) in an extensional environment. The enrichment of the mantle source could be ascribed to the metasomatism by subducted-slab-released fluids before partial melting. Overall, reported Neoproterozoic igneous rocks throughout the Tarim Block constitute two major phases of Neoproterozoic igneous activities, i.e., ca. 825–800 Ma and ca. 780–745 Ma, respectively. Similar to that of many other Rodinian continents, this feature is interpreted to be related to the two phases of Neoproterozoic mantle plume activity under the Rodinia. Furthermore, there exist two types of mafic-ultramafic complex at Quruqtagh, i.e., the ca. 820 Ma carbonatite-bearing and the ca. 760 Ma tholeiitic, which could reflect the presence of two different mantle sources.  相似文献   

带乘性噪声系统的最优方差约束鲁棒状态估计算法     

褚东升  王红都  张玲 《中国海洋大学学报(自然科学版)》2011,41(4):121-126

带乘性噪声系统由于其广泛的适用性,一直成为研究的热点。针对带乘性噪声系统的鲁棒状态估计算法进行研究,利用线性矩阵不等式的方法,讨论状态方程中含有范数有界不确定性参数的带乘性噪声系统的方差约束鲁棒状态估计器存在的条件,并针对此类带乘性噪声系统推导出1套方差约束鲁棒状态估计算法以及最优方差约束鲁棒状态估计算法。仿真结果验证算法的有效性。  相似文献   

转移矩阵未知时带乘性噪声系统的自适应滤波算法     

褚东升  刘祺  张玲 《中国海洋大学学报(自然科学版)》2011,41(6):115-118,124

针对带乘性噪声系统状态转移矩阵未知的情况,提出1种在线性最小方差意义下的系统参数和状态联合滤波算法。以迭代方式获得模型参数和系统状态的递推估计:首先,利用之前时刻的状态估计值,根据投影定理,对系统未知参数即系统状态转移矩阵作出估计;其次,利用已得到的系统参数估计值,获取当前时刻的状态滤波。计算机仿真结果表明了算法的有效性。  相似文献   

A process-based model for sediment transport under various wave and current conditions   总被引：1，自引：0，他引：1  

Chi ZHANG  Jin-Hai ZHENG  Yi-Gang WANG  Meng-Tao ZHANG  Dong-Sheng JENG  and Ji-Sheng ZHANG  Dr.  State 《国际泥沙研究》2011,(4):498-512

The purpose of this study is to investigate the capability of a newly developed process-based model for sediment transport under a wide variety of wave and current conditions.The model is based on the first-order boundary layer equation and the sediment advection-diffusion equation.In particular,a modified low Reynolds number k-e model is coupled to provide the turbulence closure.Detailed model verifications have been performed by simulating a number of laboratory experiments,covering a considerable range of hydrodynamic conditions such as sinusoidal waves,asymmetric waves and wave-current interactions.The model provides satisfactory numerical results which agree well with the measured results,including the time-averaged/dependent sediment concentration profiles and sediment flux profiles,as well as the time series of concentration at given elevations.The observed influences of wave orbital velocity amplitude,wave period and sediment grain size are correctly reproduced,indicating that the fundamental physical mechanisms of those processes are properly represented in the model.It is revealed that the present model is capable of predicting sediment transport under a wide range of wave and current conditions,and can be used to further study the morphodynamic processes in real coastal regions.  相似文献   

青海玉树MS7.1级地震发震应力场与非稳定发震机理的模拟          下载免费PDF全文

王连捷  王薇  崔军文  孙东生  乔子江  赵卫华 《地球物理学报》2011,54(11):2779-2787

分析了玉树地区的地应力场、速度场.在此基础上,对青海玉树2010.4.14 MS7.1级地震发震机理进行了数值模拟.将围岩看成弹性体,断层看成具有应变软化特性的弹塑性体,断层和围岩组成统一的地质介质系统.在地应力、孔隙压力及边界位移的作用下,应力逐渐积累,当达到断层的摩擦破坏强度时,断层产生位移软化,断层突然滑动,能量...  相似文献   

一类具有等式约束的带乘性噪声系统的最优滤波算法     

褚东升  于兴凯  张玲 《中国海洋大学学报(自然科学版)》2014,44(11):101-105,124

针对动态数据处理领域观测方程中存在乘性噪声的情况,提出在乘性噪声系统中状态附等式约束的一套滤波算法。该算法首先通过把观测向量进行扩维,然后基于投影定理进行滤波求解得到基于线性最小方差的最优滤波算法。通过与基于最优化理论的方法求解得到的算法进行对比分析及仿真对比验证了该算法的有效性。  相似文献   

Effect of Sludge Retention Time on Nitrifiers' Biomass and Kinetics in an Anaerobic/Oxic Process     

Tzu‐Yi Pai  Terng‐Jou Wan  Yung‐Pin Tsai  Chwen‐Jeng Tzeng  Hsiao‐Hsing Chu  Yao‐Sheng Tsai  Ching‐Yuan Lin 《洁净——土壤、空气、水》2010,38(2):167-172

In this study, the effect of sludge retention time on ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) in an anaerobic/oxic (AO) process, was explored. The results indicated that the growth rate constants of AOB were 0.97, 0.88, and 0.79 d^–1, respectively, meanwhile, those of NOB were 1.22, 1.03, and 0.93 d^–1, respectively, when the sludge retention time (SRT) was 15 days, 10 days and 5 days. The relation between the growth rate constant and the SRT could be best described using a simple exponential curve and a second type hyperbolic curve. The lysis rate constants for AOB and NOB were 0.13 and 0.18 d^–1, respectively. The yield coefficients values of AOB and NOB were 0.22 and 0.21, respectively. The percentage of AOB to mixed liquid suspended solids (MLSS) was 0.64%, 0.53%, and 0.35%, respectively. Meanwhile, the percentage of NOB was 2.24%, 1.87%, and 1.11%, respectively, at SRT values of 15 days, 10 days and 5 days. When the SRT value decreased, the AOB and NOB biomass levels decreased by 12.75 and 47.01 mg L^–1, respectively. Meanwhile the removal efficiency of NH₄⁺‐N decreased from 90 to 26%, while the removal efficiency of total nitrogen (TN) decreased from 14 to 8%.  相似文献   

云南高黎贡山典型板岩地震波各向异性研究          下载免费PDF全文

郭彬彬  王红才  赵卫华  嵇少丞  孙东生  李阿伟  龙长兴 《地球物理学报》2014,57(3):837-846

板岩作为一种浅变质岩在我国有着广泛的分布,对其地震波速度的研究将有助于对这类过渡性岩石的有效区分,对于浅层地壳的各向异性研究也具有重要意义.本文对采自云南丙中洛地区的板岩样品进行了地震波速度的室内实验研究,其中部分实验是在加拿大Dalhousie High Pressure Laboratory完成.实验获得了板岩在围压10~600 MPa条件下、不同构造主方向（X,Y和Z）上的地震波速度,在围压600 MPa时,X、Y、Z三个方向的P波速度分别为6.58、6.46、5.91 km/s,平均速度为6.30 km/s,S波平均速度约为3.62 km/s,V_P/V_S=1.74;并初步分析了板岩地震波速度、横波分裂及其波速各向异性随着围压的变化规律,发现所测量的板岩在较低围压（<150 MPa）时波速的各向异性随围压升高而迅速减小,主要是由于其内部微裂隙的定向排列引起的,而随着围压的继续增加（>150 MPa时）微裂隙基本闭合,黑云母、阳起石等片状矿物的定向排列成为其地震波各向异性的主导诱因,此时（围压为600 MPa）V_P、V_S的各向异性分别稳定在13%、16%左右.本研究所获取的基础实验数据及所探讨的板岩地震波性质将为确定地壳上部显微裂隙的优选定向、浅层地壳的各向异性分析、地球物理模型条件约束等提供基础.  相似文献   

中扬子江汉平原簰洲湾地区中、新生代构造-热演化史          下载免费PDF全文

李天义  何治亮  何生  周雁  孙冬胜  沃玉进  杨兴业  王励 《地球物理学报》2014,57(6):1868-1882

本文综合运用磷灰石-锆石裂变径迹和（U-Th）/He、镜质体反射率及盆地模拟等手段,深入细致地探讨了中扬子江汉平原簰洲湾地区中、新生代构造-热史演化过程.研究结果表明,研究区中-新生代大规模构造抬升剥蚀、地层冷却事件始于早白垩世（140-130 Ma）;大规模抬升冷却过程主要发生在早白垩世中后期至晚白垩世.研究区虽然可能存在一定厚度的晚白垩世-古近纪地层沉积,总体沉积规模相对较小.综合分析认为,区内应该存在较大厚度的中侏罗统或/和上侏罗统乃至早白垩世地层的沉积;而现今残存中生代中、上侏罗统地层相对较薄,主要是由于后期持续构造抬升剥蚀造成的,估计总剥蚀厚度约4300 m左右.区内中生代地层在早白垩世达到最大古地温,而不是在古近纪沉积末期;上三叠统地层最大古地温在170~190℃之间.热史分析结果表明,区内古生代古热流相对稳定,平均热流在53.64 mW·m^-2;早侏罗世末期古热流开始降低,在早白垩世初期古热流约为48.38 mW·m^-2.  相似文献   

基于红树林种植的滨海湿地恢复效果研究   总被引：1，自引：1，他引：0  

徐华林  彭逸生  葛仙梅  李适宇  管东生  陈桂珠 《湿地科学与管理》2012,8(3):36-40

滨海湿地具有重要的生态意义和社会价值。由于社会经济的高速发展,滨海湿地面临着退化和消失的状况。基于红树林种植的滨海湿地恢复模式,是华南沿海传统围垦养殖区湿地恢复的方式之一。对深圳湾滨海湿地恢复工程开展为期1a的监测分析,结果显示:红树植物桐花树Aegiceras corniculatum对人工湿地生境适应性较好,秋茄Kandelia obovata、木榄Bruguiera gymnorrhiza需要在一定人工辅助条件下进行栽培。人工恢复湿地可使遭受污染的4类海水指标大幅改善,溶解氧、COD分别净化为Ⅱ类和Ⅲ类。建议今后尝试增加种植红树植物的种类,使用红树小苗并采取密植,投入适度的人工管理,延长水质处理期,采取多级水循环流程。  相似文献