Morphodynamics of a mesotidal rocky beach: Palmeras beach,Gorgona Island National Natural Park,Colombia

The response of a rocky beach to different possible combinations of hydrodynamic conditions (tides, waves, oceanic currents) has been little studied. In this work, the morphodynamic response to different hydrodynamic forcing is evaluated from sedimentological and geomorphological analysis in seasonal and medium term (19 years) scale in Palmeras beach, located in the southwest of Gorgona Island National Natural Park (NNP), a mesotidal rocky island on the Colombian Pacific continental shelf. Palmeras is an important nesting area of two types of marine turtles, with no anthropogenic stress. In the last years, coastal erosion has reduced the beach width, restricting the safe areas for nesting and conservation of these species. Until now, the sinks, sources, reservoirs, rates, and paths of sediments were unknown, as well as their hydrodynamic forcing. The beach seasonal variability, from October 2010 to August 2012, was analyzed based on biweekly or monthly measurements of five beach profiles distributed every 200 m along the 1.2 km of beach length. The main paths for sediment transport were defined from the modeling of wave currents with the SMC model (Coastal Modeling System), as well as the oceanic currents, simulated for the dry and wet seasons of 2011 using the ELCOM model (Estuary and Lake COmputer Model). Extreme morphologic variations over a time span of 19 years were analyzed with the Hsu and Evans beach static equilibrium parabolic model, from one wave diffraction point which dominates the general beach plan shape. The beach lost 672 m³/m during the measuring period, and erosional processes were intensified during the wet season. The beach trends responded directly to a wave mean energy flux change, resulting in an increase of up to 14 m in the width northward and loss of sediments in the beach southward. This study showed that to obtain the integral morphodynamic behavior of a rocky beach it is necessary to combine information of hydrodynamic, sedimentology and geomorphology in different time scales.     

珠海市大万山岛海水抽水蓄能电站温排水对周边海域影响的模拟分析研究

海水抽水蓄能电站上水库温度升高可能对下水库海域海水水温产生影响,文章对珠海市大万山岛拟建的海水抽水蓄能电站温排水进行模拟分析,结果表明,海水抽水蓄能电站在设计水量12.3m3/s的条件下,下水库排水8h后,不会对所在海域海流流场产生显著影响;当排放温度为30.2℃时,春季温排水影响的面积为1.76 km2,最大温升为1.35℃,最大温升面积为0.006 km2;夏季影响面积约1.58 km2,最大温升为0.7℃,最大温升面积为0.013 km2;秋季影响面积约为1.66 km2,最大温升为0.8℃,最大温升面积约为0.085 km2;冬季影响面积约为1.95 km2,最大温升为1.9℃,最大温升面积约为0.030 km2。周边海域最大温升随着排水温度增加逐渐增加,但对应的最大温升面积变化较小。在排水温度为32.2℃时,夏季最高温升约0.9℃,冬季最高温升约2.3℃;排水温度为34.2℃,夏季最高温升约1.15℃,冬季最高温升约2.6℃。最大温升面积在0.019~0.027 km2。排水流量从10.3m3/s逐渐增加到20.3m3/s,周边海域的最大温升值增加,但最大温升面积增幅较小,当排水流量达到20.3m3/s时,最大温升值达到最大值2.25℃,最大温升面积为0.007 km2。文章的研究结果为未来大万山岛海水抽水蓄能电站的环境影响评价及周边海域生态管理提供了科学依据。     

REPORT ON PONTONIINE SHRIMPS (CRUSTACEA: DECAPODA) COLLECTED BY JOINT CHINESE-GERMAN MARINE BIOLOGY EXPEDITIONS TO HAINAN ISLAND,SOUTH CHINA SEA I. ANCHISTUS, CONCHODYTES, CORALLIOCARIS

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Evolution of Br/Cl ratios in fumarolic salammoniac from Vulcano (Aeolian Islands,Italy)

 Bromine/chlorine ratios in salammoniac samples, collected from 1983 to 1994 at the Fossa crater fumaroles of Vulcano (Aeolian Islands), were determined. The data obtained in this work have been compared to those obtained by Coradossi et al. (1985) in order to carry out a systematic study of the Br/Cl ratio variations since 1977. Br/Cl ratios range from 0.04 to 0.29. The Br/Cl ratio variations observed have been interpreted as the result of different contributions among deep and shallow components feeding the fumarolic fluids of Vulcano. The Br/Cl increases, which occurred from 1977 to 1979, in 1983–1984 and in 1992–1993, have been connected to an increased input of magmatic gases. Received: 10 November 1995 / Accepted: 12 July 1996     

REPORT ON PONTONIINE SHRIMPS（CRUSTACEA：DECAPODA）COLLECTED BY JOINT CHINESE—GERMAN MARINE BIOLOGY EXPEDITIONS TO HAINAN ISLAND,SOUTH CHINA SEA i.ANCHISTUS,CONCHODYTES,CORALLIOCARIS

The present paper reports 7 species of pontoniine shrimps collected from Hainan Island,South China Sea,by the Joint Chinese-German Marine Biology Expeditions,in which,Conchodytes nipponensis(De Haan,1844)and Coralliocaris brevirostris Borradaile,1898 are new records from Chinese waters.     

海南岛北部晚新生代玄武岩成分演化及成因讨论

板内玄武岩通常具有复杂的成分组成和成因过程。海南岛北部（简称“琼北”）自渐新世始逐渐发育了大量板内玄武岩,岩性跨度大,从石英拉斑玄武岩到橄榄拉斑玄武岩,再到碱性橄榄玄武岩和碧玄岩均有分布。对琼北晚新生代玄武岩虽已开展了广泛的研究,但“琼北晚新生代玄武岩的成分随时间演化规律”这一问题却未引起足够的关注。本文从晚更新世道堂组橄榄玄武岩入手,对其开展了细致的岩石学、矿物学和主微量及Sr- Nd- Pb同位素地球化学的研究;并结合文献中琼北其他时代（组）玄武岩的数据,阐述了琼北晚新生代玄武岩成分随时间演化的规律并对其成因进行了探讨。研究发现,自中—上新世到更新世再到全新世,琼北晚新生代玄武岩呈现从碱性玄武岩过渡到拉斑玄武岩再突变到碱性—强碱性系列的演化规律;中—上新世到更新世这一时期的碱性玄武岩和拉斑玄武岩可能形成于石榴子石二辉橄榄岩由低到高程度的部分熔融作用,而全新世碱性岩则更可能形成于石榴子石辉石岩的部分熔融。琼北晚新生代玄武岩的Sr- Nd- Pb同位素组成揭示其源区地幔以PREMA端元为主,但经历了来自古老陆壳的沉积物不同程度的改造作用。采用“海南地幔柱”模型可以较好地解释琼北晚新生代玄武岩的复杂组成和成因。     

金银岛岩土台阵原位剪切波速剖面评估

土层的剪切波速是描述土动力学特性的重要参数之一。利用金银岛岩土台阵记录的8次浅源地方震的弱震动数据,使用解卷积的地震干涉测量法识别的剪切波走时,评估了该台阵两个水平方向的原位剪切波速剖面。结果表明:在44.2m深度以上,估计与实测的平均剪切波速剖面基本一致,而在44.2m到103.6m深度范围前者大于后者;本研究估计的平均剪切波速剖面比MEHTA等（2007）估计的平均剪切波速剖面更接近实测结果,在44.2m到103.6m深度范围,本研究估计的平均剪切波速与MEHTA等（2007）估计的平均剪切波速相近,二者均大于实测的平均剪切波速。     

The genesis of pyroclasts and the mechanism of submarine eruption of Naozhou Island in Guangdong,South ChinaSCIEI北大核心CSCD

水下火山喷发作用机制不同于陆地环境喷发,随着水参与程度的变化,喷发机制趋向复杂。本文以雷琼火山群的湛江硇洲岛作为研究对象,聚焦浅海火山产物的判断依据和水下火山喷发机制。硇洲岛是我国最大的第四纪火山岛,其上的那晏湾剖面保留了完整的火山喷发堆积序列。在那晏湾剖面的凝灰岩中,主要有三类火山成因的大粒径原生碎屑(2-5mm):塑变熔岩碎屑、碎玄玻璃及玄武玻璃,推断为不同程度水-岩浆相互作用的产物,根据水的参与程度大致排序为:碎玄玻璃>玄武玻璃>塑变熔岩碎屑。通过对硇洲岛水-火山作用机制研究,发现水-岩浆混合质量比(Mwater/Mmelt)是控制爆炸强度和火山碎屑粒度的关键因素。火山喷发序列分析表明,硇洲岛的喷发过程总体可分为三期,早期是冰岛苏特塞式喷发的浅水环境蒸汽爆炸与“火喷泉”喷发;中期过渡转为“火喷泉”喷发,伴随陆上的射汽岩浆喷发;最终以岩浆溢流式喷发结束。     

Geochemical Characteristics,Petrogenesis of the Sanukitic Dikes in the Miaoergou Area of West Junggar,Xinjiang, NW China and Their Geological SignificanceEI北大核心CSCD

NS-trending dikes which contain dioritic enclaves widely occur in the Miaoergou pluton, West Junggar, Xinjiang. The dikes are composed of quartz diorite and quartz diorite porphyrite. LA-ICP-MS zircon U-Pb ages of the quartz diorite and diorite are 298.0±3.7 Ma and 299.4±2.5 Ma, respectively, corresponding to the end of the Late Carboniferous to beginning of the Early Permian. The dikes and enclaves have similar geochemical properties with island arc features. They are calc-alkaline, with moderate SiO2 (53.58% to 57.89%), high MgO (3.09% to 4.83%, Mg# values ranging from 44.69 to 54.12), TiO2 (1.17% to 1.66%), Cr (51.24×10-6 to 126.1×10-6), Ni (35.91×10-6 to 57.55×10-6) contents and K/Na ratios (0.35 to 0.70). Moreover, all samples are enriched in large-ion lithophile elements (LILEs: e.g. K, Rb, Ba and U) and light rare earth elements, but strongly depleted in high field strength elements (HFSEs: e.g. Nb, Ta and Ti), with insignificant Eu anomalies (δEu=0.67 to 1.08). In contrast, the dikes and enclaves in the Miaoergou pluton show geochemical signatures similar to those of the Cenozoic sanukitoids in Setouchi volcanic belt of SW Japan and the sanukitoids in the Hatu area, West Junggar. The source of the dikes might be the depleted mantle previously metasomatized by fluids released from subduction slabs. These sanukitic dikes may be generated by interaction of the mantle wedge with fluids derived from dehydration of the subducting oceanic slab, resulting in 2% to 5% partial melting of amphibole-spine peridotite. The identification of the sanukitic dikes in the Miaoergou pluton, together with previous studies, suggest that the southern West Junggar region was still dominated by subduction-related island arc setting at the beginning of the Early Permian, and multi-stage subduction-accretionary orogeny may account for the difference of subduction duration between the north and the south of West Junggar. © 2018, Science Press. All right reserved.     

苏拉威西岛北部左旋走滑与俯冲后撤的动力学分析

苏拉威西岛北部属于马鲁古海板块,其主体是北苏拉威西海沟俯冲带与帕卢-科洛左旋走滑断裂所围限的岛北支和岛东支。大约5 Ma前,苏拉群岛沿Sorong断层与苏拉威西岛东支碰撞,导致北苏拉威西海沟俯冲后撤,引起了岛北支顺时针旋转约20°～25°,同时,西侧的帕卢-科洛断层发生了约4 cm/a的左旋走滑。本文利用综合地球物理方法,计算了该区三维温度、速度、黏性特征,认为：苏拉威西岛北部在左旋走滑、俯冲后撤过程中,地壳以脆性变形为主,但由于北苏拉威西海沟俯冲带在地壳内形成南向倾斜的软弱层,Moho面和地形“镜像”区域内形成脆、韧变形共存的组合。地幔变形为韧性变形,深度约100 km的上地幔低速流变层是地幔韧性变形的主控层位。在周边板块边界不断移动的动力学背景中,苏拉威西岛北部在地壳尺度以收缩-伸展变形为主,在岩石圈尺度以旋转变形为主。