南海北部琼东南盆地陵水段峡谷沉积建造及勘探意义

琼东南盆地中央峡谷为一大型轴向峡谷体系,具有明显的"分段性"特征,不同区段沉积充填和内部结构均存在明显的差异,其中陵水段位于峡谷西段,具有非常好的储层物性特征,是深水区峡谷勘探的重点区域。为了进一步精细刻画陵水段峡谷内部水道复合体的沉积充填及沉积微相展布特征,本文借助新增加的三维地震资料和新钻井资料,通过峡谷三级层序界面的识别,将峡谷充填划分为3个三级层序SQ1、SQ2和SQ3,并通过古生物有孔虫化石带、钙质超微化石带及井-震结合确定了峡谷底界为中中新世晚期S40界面,陵水段峡谷自西向东依次识别出6种主要的内部充填结构,且将SQ3层序细分为5个次级层序(SSQ1~SSQ5);结合属性特征,精细刻画了陵水段峡谷内沉积微相平面展布及空间演化特征,并指出点砂坝在SSQ1层序最发育,且规模较大,横向上连片分布,将是下步勘探的有利储集体。     

深圳大鹏半岛南岸西冲海滩的沉积物来源、平面形态稳定性及横向变化

The coast of the Dapeng Peninsula has been honored as one of "the eight most beautiful coasts in China". The most precious tourism resource for the peninsula is headland bay beaches, among which the beach at Xichong on the southern coast of the peninsula is the longest and the most important one. The information of the stability, sedimentary source and shape change of the beach is very important for maintaining the beach in terms of sustainable development of the peninsula. Heavy minerals in the sand of the beach and the inland stream at Xichong are compared with those of a nearby beach on the same coast to determine the beach sand source; with help of a computer software, MEPBAY, the equilibrium planforms of the beaches on the peninsula are compared with those of an island without rivers to evaluate the stream’s effects on the beach stability; cross shore profiles along the Xichong beach are also surveyed in different seasons of a year to assess the annual shore normal beach changes affected by the stream input, and the relation between the equilibrium planform state and cross shore changes of the beach. It is shown that(1) stream is the main sedimentary source of the beach and the weathering materials of the rocky headlands on both sides of the bay transported by waves are the second source for the beach but it is limited, sand from an inner shelf is not the sedimentary source for the beach at present and was not even during the Holocene transgression;(2) the Xichong beach cannot reach static equilibrium around the entire bay shoreline, the segment of the shoreline where a stream outlet is located is in dynamic equilibrium, and the unstable section occurs in the wave shadow region in the lee of an offshore island;(3) no matter whether the section of the beach shoreline at Xichong is in an equilibrium state or not, it is eroded in the typhoon season and recovered after the season, the maximum change in erosion and accretion occurs in the unstable segment;(4) the Xichong beach can only have small sand body since it is supplied with sand mainly form inland streams, resulting in a possible danger in which sand loss induced by human activities or huge storms cannot be replenished naturally.     

长江口表层沉积物矿物磁性分区特征及其沉积环境指示意义

本研究旨在揭示现代长江口不同沉积环境铁磁性矿物的分布差异,寻找有效识别河口-陆架沉积环境的磁学指标,以便更好地将环境磁学应用于河口古环境研究。在长江口及邻近陆架的6个沉积环境:汊道、拦门沙、三角洲前缘斜坡、前三角洲、前三角洲-陆架过渡区和残留砂区,采集表层沉积物样品,进行粒度和磁性测量。结果显示,χ和SIRM在汊道和拦门沙呈现显著高值,HIRM、χfd%、χARM、χARM/χ和χARM/SIRM在前三角洲和前缘斜坡呈现显著高值,反映了陆源物质输运距离和河口沉积动力对磁性矿物分布的控制作用。因此,参数组合HIRM、χARM、χARM/χ和χARM/SIRM可用于识别全新世地层前缘斜坡和前三角洲-陆架;参数组合χ、SIRM和S-20mT可尝试用于识别汊道和拦门沙环境。     

强壮前沟藻(Amphidinium carterae Hulbert)在多重逆境条件下的生长和生理响应

尽管单一逆境条件对浮游植物产生的影响已被广泛重视,然而对于多重逆境条件对藻细胞生长生理的研究仍有空白。本研究通过测定强壮前沟藻(Amphidinium carterae Hulbert)光密度(OD750)、叶绿素a含量(chl a)、光合作用效率(F_v/F_m)、碳氮比(C/N)等多个生理指标,分析其在9种环境下(常温光照、低温和低温黑暗三种物理环境,结合全营养、缺氮、缺磷三种营养状态)对多重逆境的生长和生理响应。研究结果表明,在多重逆境条件下,单一物理逆境因素(低温或黑暗)较氮限制或磷限制对藻细胞生长和生理的不利影响更为显著。营养限制并同低温环境双重作用对生物量和碳氮比产生显著性影响(P0.01)。此外,低温和黑暗条件耦合作用下,SYTOX Green染色强度处于较低水平,chl a稳定、F_v/F_m有所升高,强壮前沟藻在逆境环境下作为群体的衰亡得以缓解。     

琼东南盆地深水区新近系海底扇沉积特征与资源潜力

综合利用钻井、岩心、薄片及分析化验资料研究了琼东南盆地深水区新近系海底扇沉积特征,并利用最新的三维地震资料,通过井震精细标定、多属性融合技术、方差体切片、三维地貌砂体镂空等综合技术手段,精细刻画了海底扇砂体的空间分布特征。研究结果表明,深水区新近系海底扇是由陆架区的砂体滑塌并二次搬运形成,形成过程具有多期次性。受不同物源的影响,海底扇岩性和物性存在较大的差异。海底扇岩性及沉积构造具有砂质滑塌、碎屑流、浊流和深水底流改造的特征。海底扇的沉积微相、厚度、砂泥比和砂泥岩空间配置关系直接控制了地震振幅反射强度和频率的变化。砂体纵向叠置,横向连片,并被后期泥质水道切割分块形成多个岩性圈闭。综合分析认为,深水区海底扇砂体发育区烃源条件优越,储盖配置关系和圈闭条件良好,具备形成大中型岩性油气藏的有利条件,具有较大的油气勘探潜力。     

南黄海太阳沙西侧潮流脊槽的沉积物分布特征和沉积环境演变

对南黄海太阳沙西侧潮流脊槽区进行了底质调查,采用密集站位的振动活塞柱状沉积物采样器取样。根据粒度分析结果,比较精细地研究了厚度约2～3 m浅表层沉积物的空间分布特征。结果表明:表层沉积物中,细砂主要分布在潮流脊和岸滩上,其它较细的沉积类型主要分布于潮流槽内,呈显“脊砂槽泥”的沉积地貌基本特征。同时,沙脊上的表层细砂的分布范围明显与沙脊至海岸的距离有关,除了潮流的影响外,主要与外侧沙脊的消浪作用有关。另外,根据表层沉积物分布的沉积地貌特征,探讨了潮流脊槽的沉积环境演变。     

南海西北部琼东南盆地陆架坡折带类型及沉积作用特征

陆架坡折带特殊的地形地貌反映了其独特的水动力和沉积特征。根据水深和高分辨率单道地震资料对琼东南盆地陆架坡折带特征进行分析,旨在探讨现代陆架坡折带的成因及其沉积作用。研究结果表明,琼东南现代陆架坡折带呈NE-SW向展布,水深变化大,形态复杂,自西向东陆架坡折差异较大。西部陆架坡折带水深范围为250~700 m,宽约7 km,高差450 m,坡度平均为2°,地形平缓,槽谷不发育;中部陆架坡折带水深范围为250~750 m,宽约10 km,高差500 m,地形平均坡度为7°,槽谷呈V型或U型,长约5~6 km,宽约3~8 km,下切深度100~300 m;东部陆架坡折带水深范围为400~1 500 m,宽约30 km,高差达1 100 m,平均坡度为10°,槽谷呈"V"型,长约13~28 km,宽约为3~4 km,下切深度最大达500 m。结合琼东南盆地构造区划和物源特征,对琼东南陆架坡折带沉积作用进行分析,划分坡折带类型。西部陆架坡折带以大量的沉积物不断加积为主,地形平缓,槽谷不发育,属堆积型陆架坡折;中部属过渡型陆架坡折带,沉积物供应量小,侵蚀和堆积作用同时存在,相互制约,槽谷规模小,滑塌作用较弱;东部为侵蚀型陆架坡折,以底流冲刷侵蚀为主,槽谷及滑塌发育。总体反映了不同区段位置沉积物供给,沉积物堆积,底流侵蚀等作用的差异,是形成现今陆架坡折地貌格局的重要因素。     

The effects of stock size and environmental variability on Cape hake recruitment in Namibia: an unsolved puzzle (a comment on Kainge et al. 2013)

Measuring and forecasting recruitment are central to the understanding and management of fish stocks. Kainge et al. (2013) studied the effect of spawning stock size and environmental fluctuations on the recruitment levels of the Cape hake Merluccius capensis in Namibia. However, their study contains some flaws that undermine the conclusion that Cape hake recruitment is under the influence of upwelling in summer. Until those flaws are properly addressed, this conclusion, in our view, should be treated with caution.     

中国北方砂栖纤毛虫的空间分布及其驱动因素

为深入了解不同地理尺度因素对驱动微型生物群落空间结构的相对影响,本研究于2020年10月调查了中国北方14个砂质潮间带的砂栖纤毛虫群落。研究结果如下：（1）检获纤毛虫105种,隶属26目65属,按丰度优势依次为帆口目、小胸目和环毛目;（2）黄海、渤海两区域的环境因子存在显著差异,但纤毛虫群落组成趋于相似;（3）偏Mental分析显示,环境条件较空间距离在纤毛虫群落组成的驱动中更为重要,其中盐度、粒度和海滩坡度是解释纤毛虫空间分布的最优环境因子组合,而潮差和溶解无机氮含量是次要影响因子;（4）沿海区域微型生物的强扩散效应在一定程度上掩盖了环境异质性影响。综上,由于沿海生态系统中微型生物受到更少扩散限制,在空间分布格局的形成上,环境条件的影响比空间距离更重要。本研究为海洋微型生物地理学提供了基础数据,有助于在全球变化背景下制定沙滩管理和保护规划。     

The Equatorial Atlantic Mid-Ocean Channel: An Ultra High-Resolution Image of Its Burial History Based on TOPAS Profiles

Multibeam bathymetric and ultra high-resolution seismic data reveal that the distal course of the Equatorial Atlantic Mid-Ocean Channel (EAMOC) extends further east and south than was previously known, and is controlled by the presence of morphologic highs related to the Fernando de Noronha Fracture Zone. Distal course of the EAMOC is buried by sediments, and does not have bathymetric expression on the seafloor. The channel fill consists of three seismic sequences, suggesting that the recent geological evolution of the channel is composed of successive phases of decreasing sedimentary activity that finally resulted in its complete burial. Tectonic and volcanic activity related to the Fernando de Noronha Fracture Zone and Ridge, together with the effect of strong pulses of the Antarctic bottom water current during the upper Pliocene are suggested to have contributed to the progressive burial and the final abandonment of the EAMOC.