关于Mckenzie沉积盆地初始沉降公式的修正     

毕传学  王良书 《海洋学研究》1993,11(2):9-12

根据Airy均衡原理对Mckenzie沉积盆地初始沉降公式进行了修正,并导出了公式的正确表达式 S=(a[(ρ_o-ρ_c)t_c/a(1-(aT_1t_c)/(2a))-(aT_1ρ_o)/2](1-1/β))/(ρ_o(1-aT_1)-ρ_w)  相似文献   

南黄海陆架沉积学研究   总被引：4，自引：0，他引：4  

申顺喜 《海洋科学》1993,17(5):24-28

黄海中部、济州岛西南,存在厚层的泥质沉积,它们分别与上述地区的冷涡活动区相对应。在两个泥质沉积区之间又出现连接它们的通道,形成别有特征的“冷涡-通道”沉积体系。经分析发现,这个沉积体系,完全受控于黄海暖流、冷涡及其相关的环流体系。此外,在黄海西南部及东海北部海底发现大面积砂岩及其砾石,揭示了黄、东海陆架沉积物的新源地。  相似文献   

潮汐沉积率与沉积间断   总被引：16，自引：3，他引：16  

李从先  王平  范代读  李铁松 《海洋地质与第四纪地质》1999,19(2):11-18

在浙北奥陶系文昌组和长江三角洲开敞型淤泥质海岸非潮道潮汐纹层研究的基础上,得出与国外同类研究相近的沉积率。现代海岸进积速度和潮坪沉积的观察及测试证明,上述沉积率是难以置信的。现代潮坪观测表明,潮汐纹层在形成过程中即包含着改造,所保留的纹层占应形成数的不到１０％,其余９０％以上被侵蚀。小型层序是风暴和平静天气的产物,为风暴层序,与大小潮周期无关。其地层中保留的数量不到应生成数的１０％,其余９０％被改造。小型层序被侵蚀,其中的纹层随之消失。致使潮坪层序中保存的纹层数仅为应形成数的０．２％。被改造的纹层和单层留下的仅是侵蚀面,即小间断。在进行潮汐沉积高分辨率的研究时应充分重视沉积间断的作用  相似文献   

南海东部海域柱样沉积物浊流沉积探讨     

章伟艳  张富元  张霄宇 《热带海洋学报》2003,22(3):36-43

利用1998年南海东部陆坡69号柱样、深海盆149号柱样、南部岛礁323号柱样沉积物的粒度、化学、古生物、矿物等鉴定分析测试资料,分析了南海东部海域发生浊流沉积的地质背景、产生浊流沉积的条件和诱发因素,进而发现南海东部浊流沉积发育,在南北陆坡及中部深海盆地均有浊流沉积层。从其出现层位看,为氧同位素2—4期,即晚更新世中晚期。从浊流沉积出现层数分析,具有自北向南浊流发生频次减弱的趋势。从浊流沉积物成分看,南海东部浊流沉积物具有多样性,北部陆坡以陆源为主,中部深海盆以陆源及火山源为主,南部岛礁以生物源为主。  相似文献   

Sources and distribution of organic matter in a river-dominated estuary (Winyah Bay, SC, USA)   总被引：12，自引：0，他引：12  

Miguel A. Goi  Maria J. Teixeira  David W. Perkey 《Estuarine, Coastal and Shelf Science》2003,57(5-6):1023-1048

The sources and distribution of organic matter (OM) in surface waters and sediments from Winyah Bay (South Carolina, USA) were investigated using a variety of analytical techniques, including elemental, stable isotope and organic biomarker analyses. Several locations along the estuary salinity gradient were sampled during four different periods of contrasting river discharge and tidal range. The dissolved organic carbon (DOC) concentrations of surface waters ranged from 7 mg l⁻¹ in the lower bay stations closest to the ocean to 20 mg l⁻¹ in the river and upper bay samples. There was a general linear relationship between DOC concentrations and salinity in three of the four sampling periods. In contrast, particulate organic carbon (POC) concentrations were significantly lower (0.1–3 mg l⁻¹) and showed no relationship with salinity. The high molecular weight dissolved OM (HMW DOM) isolated from selected water samples collected along the bay displayed atomic carbon:nitrogen ratios ([C/N]a) and stable carbon isotopic compositions of organic carbon (δ¹³C_OC) that ranged from 10 to 30 and from −28 to −25‰, respectively. Combined, such compositions indicate that in most HMW DOM samples, the majority of the OM originates from terrigenous sources, with smaller contributions from riverine and estuarine phytoplankton. In contrast, the [C/N]a ratios of particulate OM (POM) samples varied significantly among the collection periods, ranging from low values of 5 to high values of >20. Overall, the trends in [C/N]a ratios indicated that algal sources of POM were most important during the early and late summer, whereas terrigenous sources dominated in the winter and early spring.In Winyah Bay bottom sediments, the concentrations of the mineral-associated OM were positively correlated with sediment surface area. The [C/N]a ratios and δ¹³C_OC compositions of the bulk sedimentary OM ranged from 5 to 45 and from −28 to −23‰, respectively. These compositions were consistent with predominant contributions of terrigenous sources and lesser (but significant) inputs of freshwater, estuarine and marine phytoplankton. The highest terrigenous contents were found in sediments from the river and upper bay sites, with smaller contributions to the lower parts of the estuary. The yields of lignin-derived CuO oxidation products from Winyah Bay sediments indicated that the terrigenous OM in these samples was composed of variable mixtures of relatively fresh vascular plant detritus and moderately altered soil OM. Based on the lignin phenol compositions, most of this material appeared to be derived from angiosperm and gymnosperm vascular plant sources similar to those found in the upland coastal forests in this region. A few samples displayed lignin compositions that suggested a more significant contribution from marsh C₃ grasses. However, there was no evidence of inputs of Spartina alterniflora (a C₄ grass) remains from the salt marshes that surround the lower sections of Winyah Bay.  相似文献   

Surficial Sedimentary Diatoms in Okinawa Trough and Its Response to Kuroshio Current     

Lan Dongzhao  Fang Qi  Liao Lianzhao 《海洋通报(英文版)》2002,4(2)

This paper describes the relative contents of dominant diatom species and the distributive characteristics of tropical pelagic species and diatom assemblages, and also discusses the relations between the relative content of tropical pelagic species and Kuroshio Current and between the distribution of diatom assemblages and material sources. The results show that the limit of＞20% relative content of tropical pelagic species is basically consistent with the demarcation of Kuroshio Current, and that the distributions of dominant diatom species and diatom assemblages reserve the records of their closer relations to material sources.  相似文献   

秦皇岛昌黎黄金海岸的沙丘沉积和发育机理   总被引：7，自引：0，他引：7  

曾照爽  庄振业  祁兴芬  刘志杰 《海洋地质前沿》2003,19(7):23-27

昌黎黄金海岸长40km，分布1～1．5km宽的风成沙丘。主沙丘链高30～40m，顺岸线分布，与其斜交数列新月形横向沙丘链。沙丘以中细砂组成，分选极好，层理构造十分丰富。距今3～4ka以前，沙坝形成时就开始形成沙丘；1915年滦河新三角洲发育以来增加了风沙的输沙量，增高沙丘和扩宽了沙丘带。  相似文献   

地层学的发展推动油气地质理论研究的进步   总被引：2，自引：0，他引：2  

许红  李思田  吴河勇 《海洋地质前沿》2002,18(2):17-21

自上个世纪50年代以来,地层学经历了彻底的变革,逐渐由“相模式”、“沉积体系”、“地震地层学”发展到目前的“层序地层学”,形成高分辨率层序地层学和事件地层学的理论体系和研究方法。文章围绕层序地层学、高分辨率层序地层学基本方法及理论体系,与含油气系统相关关系进行了讨论。  相似文献   

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

Baraza  J.  Ercilla  G.  Farrán  M.  Casamor  J. L.  Sorribas  J.  Flores  J. A.  Sierro  F.  Wersteeg  W. 《Marine Geophysical Researches》1997,19(2):115-135

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.  相似文献   

北太平洋赤道海域表层沉积物的热释光特征及其指示意义          下载免费PDF全文

吕华华  石学法  吴永华  杨刚  魏建伟  王湘芹 《海洋学报》2007,29(3):162-171

热释光是矿物晶体接受环境核辐射作用后积蓄起来的能量在受到热激发时以光的形式释放出来的一种物理现象,它与晶体损伤、晶体中杂质混入等原因所导致的晶格缺陷有关.热释光强度的大小主要取决于自然界中长寿命放射性元素(238U,235U,230Th,40K及其子体)的衰变,与其他物理、化学、生物或人类活动无关.热释光特征能有效反映晶体形成的环境条件.热释光方法的制样简单、测量快捷,因此在辐射学、核工业、核医学、环境学、农业、考古学、地质学等领域都得到了广泛的应用.在陆地地质学上热释光方法在地质年代测定[1,2]、地层对比[3]、矿物世代划分[4]、矿床含矿评价[4,5]、陨石形成热的历史恢复[6]以及地质事件识别[7]等方面都取得了不少成果.  相似文献