Le domaine Tariquide (arc de Gibraltar,Espagne et Maroc) : succession et hiatus de la sédimentation du Jurassique supérieur au Paléocène

The originality of the Malm–Cretaceous series of the Tariquides (Gibraltar arc), as compared to those of the Rifian–Betic ‘Dorsale’ (Alboran domain), and especially with the Penibetic (Iberia) domain, is emphasized. In the Los Pastores Group, near Algeciras, Upper Tithonian nodular limestones directly lie on the Dogger and are followed by Aptychus-bearing limestones (Late Berriasian to Barremian). In the Musa Group, Rif, radiolarites are followed by siliceous limestones (Kimmeridgian–Tithonian), then by karst and massflow breccias connected to a Berriasian tectonics, by Aptychus-bearing marly limestones, then by karst filled by Turonian limestones, and finally by Maastrichtian–Palaeocene polychrome pelites, whose micropalaeontological and mineral compositions (clay minerals, FeMn nodules) refer to a deep-sea, probably infra-CCD, sedimentation. To cite this article: M. Durand-Delga et al., C. R. Geoscience 337 (2005).     

河北省地震局规划筹建用于地震应急的地理信息数据库的研究

利用Arc／Inf0，结合地震应急与辅助决策的特点，建成了河北省灾害评估与辅助决策系统，实现了以多种方式录入的空间数据，以有效的数据组织形式进行数据库管理、更新、维护、查询、检索，以多种方式输出决策所需的地理空间信息。     

Geochemistry of an Alaskan-type mafic-ultramafic complex in Eastern Desert,Egypt:New insights and constraints on the Neoproterozoic island arc magmatism

Mikbi intrusion(MI) is a part of the Neoproterozoic Nubian Shield located along the NE-SW trending major fracture zones prevailing southern Eastern Desert of Egypt. In this study, we present for the first time detailed mineralogical and bulk-rock geochemical data to infer some constraints on the parental magma genesis and to understand the tectonic processes contributed to MI formation. Lithologically, it is composed of fresh peridotite, clinopyroxenite, hornblendite, anorthosite, gabbronorite, pyroxene amphibole gabbro, amphibole gabbro and diorite. All rocks have low Th/La ratios(mostly <0.2) and lack positive Zr and Th anomalies excluding significant crustal contamination. They show very low concentrations of Nb, Ta, Zr and Hf together with sub-chondritic ratios of Nb/Ta(2-15) and Zr/Hf(19-35),suggesting that their mantle source was depleted by earlier melting extraction event. The oxygen fugacity(logfO_2) estimated from diorite biotite is around the nickel-nickel oxide buffer(NNO) indicating crystallization from a relatively oxidized magma. Amphiboles in the studied mafic-ultramafic rocks indicate relative oxygen fugacity(i.e. ΔNNO; nickel-nickel oxide) of 0.28-3 and were in equilibrium mostly with 3.77-8.24 wt.% H_2 O_melt(i.e. water content in the melt), consistent with the typical values of subduction-related magmas. Moreover, pressure estimates(0.53-6.79 kbar) indicate polybaric crystallization and suggest that the magma chamber(s) was located at relatively shallow crustal levels. The enrichment in LILE(e.g., Cs, Ba, K and Sr) and the depletion in HFSE(e.g., Th and Nb) relative to primitive mantle are consistent with island arc signature. The olivine, pyroxene and amphibole compositions also reflect arc affinity. These inferences suggest that their primary magma was derived from partial melting of a mantle source that formerly metasomatized in a subduction zone setting. Clinopyroxene and bulkrock data are consistent with orogenic tholeiitic affinity. Consequently, the mineral and bulk-rock chemistry strongly indicate crystallization from hydrous tholeiitic magma. Moreover, their trace element patterns are subparallel indicating that the various rock types possibly result from differentiation of the same primary magma. These petrological, mineralogical and geochemical characteristics show that the MI is a typical Alaskan-type complex.     

Taxonomy for surveying the use and value of geographical information!

Abstract

Understanding the use and value of geographical information in decision making has been identified as crucial to the further development of geographical information systems and related spatial analysis techniques. Research into the use of geographical information will be through surveys and case studies. A taxonomy for investigating the use of geographical information and its associated value is needed to structure the surveys and case studies. This paper presents an initial attempt at such a taxonomy, intended to support continuing research into the use and value of geographical information. The survey methodology to be supported will be mostly telephone and/or mail questionnaires, and this has influenced the structure of the taxonomy. The goal of this work is to create a taxonomy suitable for use in surveys that will enhance the understanding of the use and value of geographical information in decision making.     

Early Paleozoic continental crust accretion in the North Qinling: Evidences from geochronology,geochemistry and Sr-Nd-Hf isotopes of arc magmatic rocks in Taipingzhen areaSCIEI北大核心CSCD

二郎坪单元是位于北秦岭构造带中部的一个年轻地体,发育了大量的花岗岩类,是研究北秦岭早古生代大陆地壳增生的理想场所。本文对北秦岭构造带太平镇北英云闪长岩-奥长花岗岩体和蛮子营黑云母二长花岗岩体开展了岩石学、年代学、地球化学及Sr-Nd-Hf同位素研究。LA-ICP-MS锆石U-Pb测年表明,太平镇北奥长花岗岩和蛮子营黑云母二长花岗岩的形成时代分别为468.8±2.8Ma和462.2±1.9Ma。太平镇北岩体为高硅(71.79%-78.66%)、富钠贫钾(K_(2)O/Na_(2)O=0.27-0.77)的低钾拉斑-钙碱性系列岩石;蛮子营岩体为高硅(72.20%-74.90%)、富钾(K_(2)O/Na_(2)O=0.97-1.36)的高钾钙碱性岩石。两者轻重稀土分异均较明显,均具有富集Rb、Ba、Th、U、K等大离子亲石元素,而亏损Nb、Ta、P、Ti等高场强元素的特征。太平镇北岩体和蛮子营岩体具有类似的锆石εHf(t)值(奥长花岗岩8.2-12.7;黑云母二长花岗岩8.9-13.2)、全岩(87Sr/86Sr)i(奥长花岗岩0.704038-0.705221;二长花岗岩0.703876-0.705371)和全岩εNd(t)值(奥长花岗岩1.49-2.03;黑云母二长花岗岩1.68-1.92)。研究表明,太平镇北岩体岩浆源区为玄武质弧下地壳,岩浆结晶分异作用形成英云闪长岩和奥长花岗岩;蛮子营岩体岩浆为早期形成的英云闪长岩部分熔融形成。太平镇北岩体和蛮子营岩体均形成于洋内弧的构造环境,从弧玄武岩到富钠英云闪长岩、奥长花岗岩再到富钾的二长花岗岩,代表了地幔物质经过多阶段岩浆演化形成富硅富钾长英质地壳的过程。综上,认为洋内弧的形成和岩浆演化是北秦岭大陆地壳增生的重要方式之一。     

Joint inversion of active and passive seismic data in Central Java

Seismic and volcanic activities in Central Java, Indonesia, the area of interest of this study, are directly or indirectly related to the subduction of the Indo-Australian plate. In the framework of the MERapi AMphibious EXperiments (MERAMEX), a network consisting of about 130 seismographic stations was installed onshore and offshore in Central Java and operated for more than 150 days. In addition, 3-D active seismic experiments were carried out offshore. In this paper, we present the results of processing combined active and passive seismic data, which contain traveltimes from 292 local earthquakes and additional airgun shots along three offshore profiles. The inversion was performed using the updated LOTOS-06 code that allows processing for active and passive source data. The joint inversion of the active and passive data set considerably improves the resolution of the upper crust, especially in the offshore area in comparison to only passive data. The inversion results are verified using a series of synthetic tests. The resulting images show an exceptionally strong low-velocity anomaly (−30 per cent) in the backarc crust northward of the active volcanoes. In the upper mantle beneath the volcanoes, we observe a low-velocity anomaly inclined towards the slab, which probably reflects the paths of fluids and partially melted materials in the mantle wedge. The crust in the forearc appears to be strongly heterogeneous. The onshore part consists of two high-velocity blocks separated by a narrow low-velocity anomaly, which can be interpreted as a weakened contact zone between two rigid crustal bodies. The recent Java M _w= 6.3 earthquake (2006/05/26-UTC) occurred at the lower edge of this zone. Its focal strike slip mechanism is consistent with the orientation of this contact.     

A Balanced Route Design for Min-Max Multiple-Depot Rural Postman Problem (MMMDRPP): a police patrolling case

Providing distributed services on road networks is an essential concern for many applications, such as mail delivery, logistics and police patrolling. Designing effective and balanced routes for these applications is challenging, especially when involving multiple postmen from distinct depots. In this research, we formulate this routing problem as a Min-Max Multiple-Depot Rural Postman Problem (MMMDRPP). To solve this routing problem, we develop an efficient tabu-search-based algorithm and propose three novel lower bounds to evaluate the routes. To demonstrate its practical usefulness, we show how to formulate the route design for police patrolling in London as an MMMDRPP and generate balanced routes using the proposed algorithm. Furthermore, the algorithm is tested on multiple adapted benchmark problems. The results demonstrate the efficiency of the algorithm in generating balanced routes.     

“伊斯兰弧带”动荡的原因分析及对中国安全的警示

2011年发生的埃及等中东-北非国家的持续动荡,均发生在所谓的"伊斯兰弧带"。此次动荡具有持续时间长、影响深、社会基础广泛等特征。骚乱的原因,主要是历史上宗教冲突遗留下的仇恨、美国等西方势力的干涉、中东-北非地区国家内部现代化转型障碍重重等。在更深的层次上,此次乱局也是现有国际政治结构失衡的一种折射。中国需要细致评估动乱对中国安全的警示意义,提升对中东一北非地区事务的政治影响力,更好地维护本国在这一地区的利益。     

云南迪庆春都铜矿控矿地质条件

铜矿体赋存于印支期浅成-超浅成相的石英二长玢岩体内,具斑岩型矿床的蚀变特征,主要控矿因素为岩浆岩、岩浆侵位的地层、热液蚀变作用和构造裂隙等。是印支期甘孜-理塘洋向西俯冲造山晚期与超浅成斑（玢）岩密切有关的斑岩型铜矿床,矿区及外围具有较大的找矿潜力。     

琉球岛弧区弧前盆地新生代层序地层特征及沉积演化SCIEI北大核心CSCD

琉球弧前盆地位于菲律宾海板块北部与欧亚板块汇聚部位,发育于琉球海沟北部增生楔与琉球岛弧之间,是典型“沟-弧-盆”体系的组成单元。现利用多道地震资料,首次建立琉球弧前盆地的层序地层格架,分析其新生代层序地层特征,阐明弧前盆地沉积充填演化过程,并探讨各盆地主要物源。通过地震剖面解释分析,表明:①始新世为岛弧变质基底沉积期,晚渐新世晚期-早中新世阶段发育残余伸展盆地基底沉积,属于浅海环境,主要受岩浆活动影响,发育火山碎屑岩相;②中中新世-第四纪时期是弧前盆地的主体沉积期,盆地从半深海沉积环境向深海环境过渡,发育典型深海沉积相,局部为火山碎屑岩相;中中新世时北部的南琉球群岛是弧前盆地主要物源区;晚中新世至第四纪时期,台湾岛东北部陆区成为对该弧前盆地贡献最大的物源区,而南琉球群岛的物源供给量降为次要地位。该研究结果是对琉球岛弧及周缘构造控盆作用研究的拓展,并对台湾岛陆地与东部海域“源-汇”系统研究有重要的指导意义。