On facies belts and facies mosaics: Holocene isolated platforms,South China Sea          下载免费PDF全文

Eugene C. Rankey 《Sedimentology》2016,63(7):2190-2216

Although the general criteria for recognition and environmental interpretation of different carbonate facies are well‐established, a predictive understanding of the areal extent and spatial patterning of facies bodies and why they might organize into facies belts or facies mosaics is poorly constrained. To explore patterns and process dynamics of facies on isolated carbonate platforms, quantitative analysis of thematic maps derived from remote sensing images of 27 Holocene atolls of the Paracel and Spratly chains in the South China Sea explores variability within and among platforms. On these systems, most annular shelf‐margin reefs are less than 500 m wide on both chains; inboard of the reefs, reef sand aprons range up to 500 m (Spratlys) and 1000 m (Paracels) wide. Around individual platforms, Spratly Chain sand apron widths are wider to the north‐west, whereas apron widths in the Paracel Chain are more symmetrical; collectively, data indicate log‐normal width‐exceedance probability distributions. Platform‐interior patch reefs include area‐exceedance probability distributions and gap size distributions (lacunarity) consistent within chains, but distinct between the chains. To understand the processes underlying distinct distributions, simulations explored distinct growth scenarios. Results suggest that differences may represent distinct process classes: proportional growth processes with multiplicative random effects (reef sand aprons – belts), versus non‐linear, size‐proportional growth of randomly aged and distributed elements (patch reefs – mosaics). The probabilistically distinct sizes and spatial patterns of geomorphic elements within these general process classes are interpreted to represent ‘variations on themes’ related to the different impacts of tropical storms, winter cold fronts and circulation in each chain. The results highlight fundamentally different growth patterns impacting the sizes and distribution of facies belts and mosaics on isolated carbonate platforms. Because these types of bodies ultimately construct stratigraphy, the themes could be applied to understand and predict variability in the architecture of subsurface reservoir analogues.  相似文献   

Facies and depositional settings of the Middle Eocene-Oligocene carbonates in Kutch     

Santanu Banerjee  Sonal Khanolkar  Pratul Kumar Saraswati 《Geodinamica Acta》2018,30(1):119-136

Middle Eocene Fulra Limestone and Oligocene Maniyara Fort Formation represent platform carbonate deposits of Kutch at the north-western margin of India. These carbonates contain larger benthic foraminifera, including Alveolina, Assilina, Discocyclina, Lepidocyclina, Miogypsina, Nummulites and Spiroclypeus. This study presents paleodepositional and paleobathymetric interpretations for both formations using benthic foraminifera in combination with lithological association, sedimentary structures and early diagenetic features. The six carbonate facies comprising the Fulra Limestone indicate a depositional spectrum ranging from bar-lagoon to mid-ramp depositional conditions. It records several shallowing upward cycles, leading to emergence and formation of paleokarst. The four carbonate facies of the Maniyara Fort Formation represents deposition within the inner ramp setting in bar-lagoon and patch-reef environment, while intervening fine siliciclastics correspond to episodes of relative sea level fall. Nummulitic accumulations form low-relief bars within the fair weather wave base in both the formations. The depositional setting of the Paleogene carbonate in Kutch broadly resembles Eocene platformal deposits in the circum-Tethys belt.  相似文献   

Geological Interpretation and Hydrocarbon Exploration Potential of Three Types of Mound‐shaped Reflectors in the Meishan Formation,Southern Qiongdongnan Basin     

FENG Yangwei  REN Yan  LI Zengxue  JIN Li 《《地质学报》英文版》2021,95(1):167-176

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南海典型珊瑚礁生态系统健康评价方法研究     

吴莹莹  雷新明  黄晖  张浴阳  丁德文 《热带海洋学报》2021,40(4):84-97

本研究基于系统复杂性原理, 提出了南海典型珊瑚礁生态系统健康评价方法——组织力及系统功能评价法。该方法的评价框架包括珊瑚礁生态系统结构及功能、珊瑚礁生态系统与其他海洋生态系统间关系、与人类社会生态系统间关系、珊瑚礁生态系统发展制约因素等四大模块; 评价指标体系分为目标层、准则层、因素层、要素层等6个层级共计67个指标。同时, 本研究系统地提出了珊瑚礁生态系统健康评价的流程, 提高了珊瑚礁健康评价工作的规范性和时效性。应用组织力及系统功能评价法对2011—2018年西沙群岛珊瑚礁生态系统进行了健康评价, 结果显示自2011年起健康指数年均下降2.3%~2.4%, 除2012年、2015年健康指数稍有回升外, 其余年份均呈下降走势, 整体评价为亚健康状态。根据七连屿周边岛屿的实地考察和居民生活问卷调查结果, 2006—2008年的渔业发展、2012年的海星泛滥和2014—2015年的岛礁建设均对珊瑚礁生态系统造成了较大影响, 使10年内渔业产量下降了50%~80%。这与应用组织力及系统功能评价法的评价结果相吻合, 侧面验证了该评价方法的科学性和可行性。  相似文献   

南海珊瑚礁海域黑缘尾九棘鲈生物学特征初步研究     

洪小帆  陈作志  江艳娥  张俊  王欢欢  李媛洁  李纲 《热带海洋学报》2021,40(4):50-62

根据2018—2019年在南沙群岛和西沙群岛珊瑚礁海域采集的礁栖鱼类黑缘尾九棘鲈(Cephalopholis spiloparaea)样本, 对其群体结构、性腺成熟度、摄食强度、肥满度、年龄与生长等生物学特征进行了初步研究, 通过对比分析了南海这两个珊瑚礁海域中黑缘尾九棘鲈生物学特征的地理差异。结果表明: 在南沙海域和西沙海域中黑缘尾九棘鲈的平均体长分别为105.5±10.5mm和110.4±13.1mm, 两海域间的体长和体质量分布均具有极显著的差异(P<0.01); 南沙海域与西沙海域样本体长和体质量关系的异速生长因子b值分别为2.881与2.797; 耳石样本分析结果显示年龄范围为0.58~1.44a, 两个海域间并无显著性差异(P>0.05); 由von Bertalanffy生长方程计算所得的生长参数显示, 南沙海域的黑缘尾九棘鲈比西沙海域的体型相对较小、生长速度相对较快; 两海域黑缘尾九棘鲈的性腺成熟度均以Ⅱ期为主, 且西沙海域样本性腺成熟比例高于南沙海域; 摄食等级以1级为主, 两个海域间的摄食等级分布无显著性差异(P>0.05); 与西沙群岛海域相比, 南沙群岛海域的黑缘尾九棘鲈群体表现出肝体比较低的特征。  相似文献   

川东北地区二叠系长兴组生物礁类型及控制因素   总被引：3，自引：1，他引：2  

赵文光  郭彤楼  蔡忠贤  黄仁春  杨博  段金宝 《现代地质》2010,24(5)

川东北地区二叠系长兴组生物礁内蕴含大量的天然气,为该区主力储层之一。长兴组生物礁类型有台地边缘礁和浅缓坡生物礁,均出现在高位期,主要分布在梁平-开江陆棚两侧。陆棚东侧是以普光地区为代表的台地边缘礁,西侧是以元坝地区为代表的浅缓坡生物礁。与浅缓坡生物礁相比,台地边缘礁具有规模大、期次少、造礁生物相对单一的特点。生物礁类型的差异主要受控于构造作用和沉积作用,构造作用的差异决定了生物礁发育的潜力,而沉积作用则决定了生物礁的规模。  相似文献   

礁体及沉积特征在高分辨率相干属性剖面上的特征分析   总被引：2，自引：1，他引：1  

程谦  阎建国  朱强  帅庆伟 《物探化探计算技术》2010,32(1):48-53

目前国内、外主要应用相干分析技术进行断层裂缝识别和河道砂体空间展布特征等的分析,而且也主要应用相干体的平面特征来进行平面分析。我们发现,相干体的剖面细节信息对于一些沉积特征(上超、前积等)和礁体特征(边界、内幕等)往往要比原始的振幅剖面特征清楚得多。特别是利用高分辨率相干分析结果,完全可以在相干属性剖面上进行一些沉积特征的分析,甚至层位的对比解释等。这里结合实际地震资料,探讨总结了礁体及相关沉积现象在相干属性剖面上的特征,并结合相干属性的平面特征进行了礁体及沉积特征的识别,取得了良好效果。  相似文献   

鄂尔多斯盆地南缘下奥陶统马家沟组马六段成藏潜力分析     

白海峰  马占荣  刘宝宪 《西北地质》2010,43(1):107-114

鄂尔多斯盆地下奥陶统马家沟组马六段在盆地南缘广泛分布,从北向南厚度增大。岩性为含藻石灰岩、云斑灰岩、粉晶白云岩和颗粒白云岩。从早奥陶世华北地台南缘大地构造背景出发,分析了鄂尔多斯盆地南缘下奥陶统马家沟组马六段的沉积环境和沉积模式。综合露头剖面与井下岩心分析资料及岩性组合特征,探讨了马六段成藏要素及其空间配置关系,指出马六段以局限洼地和白云质石灰岩台坪沉积为主,局部层段发育礁滩相沉积,经后期成岩白云岩化可形成有效的白云岩储层,与上覆富含泥质的平凉组共同形成上生下储型成藏组合,具有一定的资源潜力。  相似文献   

Further planktonic algae of Auckland sewage treatment ponds and other waters     

A. Haughey 《新西兰海洋与淡水研究杂志》2013,47(2):245-261

Seventeen species of algae, newly recorded between 1965 and 1968 from sewage treatment ponds around Auckland City, are described together with another 11 species found in eutrophic waters of the area. These latter natural waters are often of a transient nature and usually heavily polluted in some way.

The genera recorded, with number of species (in brackets), are: Flagellata: Euglena (5); Lepocinclis (1); Phacus (3); Trachelomonas (1). Chlorophyceae (Volvocales): Chlamydomonas (1); Pteromonas (1); Pyrobotrys (1); Chloro‐gonium (1) (Chlorocoecales): Coelastrum (1); Tetrallantos (1); Closteriopsis (1) Scenedesmus (5). (Conjugates) : Closterium (3). Myxophyceae: Anabaena (1); Arthrospira (1); Oscillatoria (1).  相似文献   

Pycnogonida of the snares islands∗     

W. C. Clark 《新西兰海洋与淡水研究杂志》2013,47(2):329-341

Eight species of Pycnogonida collected by University of Canterbury Expeditions and the New Zealand Oceanographic Institute are recorded from the Snares Islands, which lie at 48° 05’ S, 166° 20’ E, 60 miles SW of South Cape, Stewart Island. The following species are recorded: Pallenopsis obliqua (Thomson, 1884), Cheilopallene trappa n.sp., Ammothea magniceps Thomson, 1884, Achelia dohrni (Thomson, 1884), Tanystylum cavidorsum Stock, 1957, Ascorhynchus insularum n.sp., Austrodecus minutum n.sp. and Austrodecus enzoi n.sp.  相似文献