Geographical variation in metazoan parasites of the deep-sea fish Bathypterois mediterraneus Bauchot, 1962 (Osteichthyes: Ipnopidae) from the Western Mediterranean

This study examines the parasite fauna of Bathypterois mediterraneus, the most common fish below 1500 m in Western Mediterranean waters. Samples were obtained during July 2010 from the continental slope of two different areas (off Catalonia and Balearic Islands) in three different bathymetric strata at depths between 1000 and 2200 m. The parasite fauna of B. mediterraneus included a narrow range of species: Steringophorus cf. dorsolineatum, Scolex pleuronectis, Hysterothylacium aduncum, Anisakis sp. larva 3 type II and Sarcotretes sp. Steringophorus cf. dorsolineatum and H. aduncum were the most predominant parasites. H. aduncum showed significant differences in abundance between depths of 2000–2200 m with 1000–1400 m and 1400–2000 m, irrespective of locality, whereas S. cf. dorsolineatum showed significant differences between the two localities at all depths except for 2000–2200 m. We suggest the possible usefulness of these two parasites as geographical indicators for discriminating discrete stocks of B. mediterraneus in Western Mediterranean waters.     

Asphalt mounds and associated biota on the Angolan margin

Release of hydrocarbons from sediments is important in increasing habitat heterogeneity on deep ocean margins. Heterogeneity arises from variation in abiotic and biotic conditions, including changes in substratum, geochemistry, fluid flow, biological communities and ecological interactions. The seepage of heavy hydrocarbons to the seafloor is less well studied than most other cold seep systems and may lead to the formation of asphalt mounds. These have been described from several regions, particularly the Gulf of Mexico. Here, we describe the structure, potential formation and biology of a large asphalt mound province in Block 31SE Angola. A total of 2254 distinct mound features was identified by side-scan sonar, covering a total area of 3.7 km² of seafloor. The asphalt mounds took a number of forms from small (<0.5 m diameter; 13% observations) mounds to large extensive (<50 m diameter) structures. Some of the observed mounds were associated with authigenic carbonate and active seepage (living chemosynthetic fauna present in addition to the asphalt). The asphalt mounds are seabed accumulations of heavy hydrocarbons formed from subsurface migration and fractionation of reservoir hydrocarbons primarily through a network of faults. In Angola these processes are controlled by subsurface movement of salt structures. The asphalt mounds were typically densely covered with epifauna (74.5% of mounds imaged had visible epifauna) although individual mounds varied considerably in epifaunal coverage. Of the 49 non-chemosynthetic megafaunal taxa observed, 19 taxa were only found on hard substrata (including asphalt mounds), 2 fish species inhabited the asphalt mounds preferentially and 27 taxa were apparently normal soft-sediment fauna. Antipatharians (3.6±2.3% s.e.) and poriferans (2.6±1.9% s.e.) accounted for the highest mean percentage of the observed cover, with actinarians (0.9±0.4% s.e.) and alcyonaceans (0.4±0.2% s.e.) covering smaller proportions of the area. Asphalt mounds represent a common and important habitat on several margin systems globally and should be recognised in future environmental assessment and management of these areas.     

河流相建模算法Fluvsim的一种改进方法

冲积扇沉积体系是我国陆相沉积的重要的沉积类型,目前缺少专门针对冲积扇储层的建模方法.冲积扇储层中的辫流水道具有河道的几何形态,因此,可以用基于目标的层次模拟Fluvsim算法对其进行建模.Fluvsim能够较好地刻画河道的几何形态,但是无法刻画辫流水道翼部单侧沉积的沉积模式.通过对Fluvsim的改进,形成了一种针对这种沉积模式的建模方法,模拟结果较好地刻画了辫流水道翼部单侧沉积的沉积模式,更真实地刻画了河道几何形态,为精细描述河道沙体的空间展布以及地质储量计算提供了基础.     

南海西北部琼东南盆地深水沉积环境演化及其油气勘探意义

Over the past several years, a number of hydrocarbon reservoirs have been discovered in the deepwater area of Qiongdongnan Basin, northwestern South China Sea. These oil/gas fields demonstrate that the...     

咸化湖盆细粒重力流沉积特征及其页岩油勘探意义——以准噶尔盆地玛湖凹陷风城组为例

细粒重力流沉积作用是咸水深湖环境重要的沉积作用过程之一,它能把浅水细粒碎屑和有机质搬运到深湖,形成页岩油的甜点储层和优质源岩。开展咸化湖盆细粒重力流沉积特征的研究对陆相盆地页岩油评价具有重要的意义。准噶尔盆地玛湖凹陷风城组(P₁f)沉积时期发育了一套咸水湖泊环境下的湖底扇沉积体系,研究表明该体系扇缘可发育8类细粒重力流岩相组合：(1)细粒浓缩密度流-细粒过渡流-细粒碎屑流岩相组合;(2)细粒异重流岩相组合;(3)细粒浓缩密度流-细粒碎屑流岩相组合;(4)细粒浓缩密度流-泥流-安静水体空落岩相组合;(5)细粒过渡流-细粒碎屑流岩相组合;(6)细粒碎屑流-泥流岩相组合;(7)细粒碎屑流-湍流尾流岩相组合;(8)细粒下部过渡塞流-细粒上部过渡塞流-准层状泥(塞)流岩相组合。这8种岩相组合是细粒重力流沉积作用相互转化的结果,它们属于不完整的混合事件层,可构成一个完整的混合事件层。咸化湖盆、深层热卤水和凝灰质的加入使该湖底扇沉积体系的沉积物普遍含白云石、碳酸钠钙石、苏打石和硅硼钠石等矿物。其中,白云石为化学沉淀的方解石在准同生期和浅埋期形成的准同生白云石,碳酸钠钙石、苏打石...     

Machine learning-based identification for the main influencing factors of alluvial fan development in the Lhasa River Basin,Qinghai-Tibet Plateau

Journal of Geographical Sciences - Alluvial fans are an important land resource in the Qinghai-Tibet Plateau with the expansion of human activities. However, the factors of alluvial fan development...     

准噶尔盆地南缘八道湾组扇三角洲露头基准面旋回与储层的响应关系

准噶尔盆地南缘八道湾组四棵树剖面发育扇三角洲沉积,可划分为2个长期基准面旋回,并细分为3个中期旋回。基于露头精细解剖,将扇三角洲成因砂体分为叠加型、过渡型及孤立型砂体3种类型,分别对应于辫状水道、辫状水道向分流水道过渡及分流水道成因,其宽度、厚度及宽厚比由叠加型向孤立型逐渐减小。3类砂体的特征、形成与变化与基准面旋回变化及所处的位置有关。A/S比值由低到高依次发育叠加型、过渡型、孤立型砂体。水道砂体的规模与A/S比值呈负相关关系,即随A/S比值的增大而减小。随着基准面的上升,八道湾组水道砂体出现的频率减小,叠加厚度减薄,砂体之间的连通性变差,水道砂体的粒度变细,发育于陆地的古土壤减少,且宽厚比也逐渐减小。     

我国参加大洋钻探的近十年回顾与展望

1999年南海首次大洋钻探,有力促进了中国的深海研究,使中国进入了国际深海研究的前沿。15年后第二次南海大洋钻探的实施,标志着中国在该国际计划中作用的加强。回顾了参加IODP 10年(2003—2013年)来深海研究的进展,并展望未来,讨论中国大洋钻探在新10年IODP(2013—2023年)中的打算。中国大洋钻探提出了分3步走的发展计划:第一步争取再实现1~2次"互补性(CPP)"大洋钻探航次;第二步学习欧盟,争取也成为IODP的"钻探平台提供者";第三步和国际科技界合作,建造新一代的中国大洋钻探船。     

潍北凹陷孔二段沉积特征

综合运用岩心、钻井、测井及地震资料,对潍北凹陷古近系孔二段地层特征及沉积演化进行了系统研究。结果表明,潍北凹陷孔二段可以划分为两个中期旋回和9个短期旋回。受到早期古城-潍河口断裂强烈活动的影响,在盆地西北部存在一个沉积沉降中心,地层向南部超覆,由北向南变薄。孔二段主要发育扇三角洲相和湖泊相,古城-潍河口断裂下降盘发育小规模近岸水下扇相。孔二下亚段为盆地初始形成期沉积,湖盆水体较浅,半深湖相仅在古城-潍河口断层下降盘发育,物源供给少且粒度较细;孔二中亚段沉积时期,物源供给充足,南部斜坡带、瓦城断阶带和灶户断鼻带发育大规模的扇三角洲相,扇体前端发育大规模滨浅湖滩坝相;孔二上亚段沉积时期,湖盆水体最深,发育大范围的半湖相沉积,物源供给减少,南部斜坡带、瓦城断阶带和灶户断鼻带继承性发育扇三角洲相,但分布范围变小。扇三角洲前缘水下分流河道砂体、浊积扇及滩坝砂体是孔二段的有利储集砂体。     

Geochemistry and mineralogy of REY-rich mud in the eastern Indian Ocean

Deep-sea sediments in parts of the Pacific Ocean were recently found to contain remarkably high concentrations of rare-earth elements and yttrium (REY) of possible economic significance. Here we report similar REY-rich mud in a core section from Deep Sea Drilling Project Site 213 in the eastern Indian Ocean. The sediments consist mainly of siliceous ooze, with subordinate zeolitic clay that contains relatively high REY concentrations. The maximum and average total REY (ΣREY) contents of this material are 1113 and 629 ppm, respectively, which are comparable to those reported from the Pacific Ocean. The REY-rich mud at Site 213 shows enrichment in heavy rare-earth elements, negative Ce anomalies, and relatively low Fe₂O₃/ΣREY ratios, similar to those in the Pacific Ocean. In addition, the major-element composition of the Indian Ocean REY-rich mud indicates slight enrichment in lithogenic components, which probably reflects a contribution from southern African eolian dust. A volcaniclastic component from neighboring mid-ocean ridges or intraplate volcanoes is also apparent. Elemental compositions and X-ray diffraction patterns for bulk sediment, and microscopic observation and elemental mapping of a polished thin section, demonstrate the presence of phillipsite and biogenic apatite, such as fish debris, in the REY-rich mud. The strong correlation between total REY content and apatite abundance implies that apatite plays an important role as a host phase of REY in the present deep-sea sediment column. However, positive correlations between ΣREY and elements not present in apatite (e.g., Fe₂O₃, MnO, and TiO₂) imply that the REY-rich mud is not formed by a simple mixture of REY-enriched apatite and other components.