Stratigraphic implications of Sinian-Early Cambrian volcanic ash beds on the Yangtze Platform

Volcanic ash beds from shallow- to deep-water facies strata of the Sinian-Early Cambrian (Meishucunian) on the Yangtze Platform consist of bentonites and tuffites which are readily recognized in the field by their physical features and confirmed by geochemical analyses.Geochemistry suggests that the volcanic ash beds in Meishucunian time are rhyolite and rhyodacite while those in the Qiongzhusian and Sinian are andesite and trachyandesite.The ash beds in the time-equivalent strata, even in different areas display rather similar geochemical features, whereas the ash beds in different strata even in the same areas show large chemical difference.The results suggest that these ash beds can be used for intra- and extra-basinal correlations of the Sinian-Early Cambrian interval on the Yangtze Platform.Additionally, these ash beds suggest high potentials for further U-Pb dating strategies.     

NPP distribution related to the terrains along the North-South Transect of Eastern China

Vegetation net primary productivity (NPP) is defined as the accumulative amount of organic matters per unit area and time, which is calculated from the difference between accumulative photosynthesis and accumulative autotrophic respiration by green plants. Since the NPP reflects the physiological and ecological characteristics of the plants and the interactive results of the environmental factors, it is an important index to evaluate a structure of ecological system, functional features and …     

Simulation of meridional overturning in the upper layer of the South China Sea with an idealized bottom topography

The South China Sea (SCS) is the largest marginal sea in the northwestern Pacific. Several important water gateways exist around the SCS, such as Luzon Strait, Taiwan Strait, etc., that lie in the northeastern SCS, and others like Kalimantan Strait, Balawan Strait, etc., lie in the south. Luzon Strait connects the SCS and Pacific via the Philippine Sea, and its water exchange has significant impact on the interior circulations of the SCS[1]. Since direct observation data about the …     

Deep-water Earliest Oligocene Glacial Maximum （EOGM） in South Atlantic

The most prominent cooling event of the Earth surface during Cenozoic in the long-term transition from a non-glaciated planet, or “green-house world”, to a polar, glaciated planet, or “ice-house world”, is the Earliest Oligocene Glacial Maximum (EOGM) above the Eocene/Oligocene boundary at about 33.7 Ma. Planktonic and benthic foraminiferal oxygen and carbon isotopes, carbonate content, and coarse fraction, along with high-resolution color reflectance and magnetic susceptibility records during 35-30 Ma, from deep-water Sites 1262 and 1265, Ocean Drilling Program (ODP) Leg 208 in South Atlantic, reveal the global cooling event occurring in both surface and deep oceans. The results show that the earliest Oligocene δ^18O values during 33.5-33.1 Ma represent the magnitude of continental ice sheets on east Antarctica and indicate the large decrease in both surface and deep water temperatures of worldwideoceans. The δ^13C records show the large excursion during the period of EOGM event and indicate some types of shift in global carbon reservoir, probably demonstrating the sudden increase in organic carbon burial rates and the changes in the distribution and timing of production. At the same time, lithologic composition, carbonate content, color reflectance, and coarse fraction brought about significant changes close to the Eocene/Oligocene boundary, reflecting the abrupt deepening in the carbonate compensation depth (CCD). Changes in carbonate content were revealed from the color reflectance identify periodicities associated with eccentricity of the Earth‘s orbit (100 and 400 ka), further indicating orbitally forced global climate variations in the Early Oligocene.     

南图尔盖盆地SA区块河道砂体演化及定量刻画

针对河道砂体横向变化快而难以有效刻画评价的问题,综合应用分频检测、相位调整、地层切片及地质体雕刻等技术对南图尔盖盆地SA区块上侏罗统阿克萨布拉克组河道发育特征及期次进行了研究。首先,利用分频方法检测出目的层段可能存在的两期调谐厚度不同的河道沉积体;然后,采用波阻抗分析和90°相位转换,揭示目的层段地震负振幅与河道砂岩具有较好的对应关系;最后,在高频层序地层格架内制作等时地层切片的基础上,通过河道沉积特征及典型地层切片振幅的单井标定分析,识别并分期刻画出两期不同类型的河道砂体。结合河道弯度、宽厚比及储集体积等参数综合分析认为,早期河道具有低弯度曲流河特征,晚期河道为具有平直河特征的三角洲平原分流河道,且早期河道储集体积明显高于晚期河道。     

Biogeography of coastal and anchialine amphipods of Ascension Island,South Atlantic Ocean

Over 8000 amphipods were examined from coastal (primarily intertidal) and anchialine pool habitats of Ascension Is. Twenty-seven species, of which 14 are undescribed, were identified. Comparison of species from Ascension with amphipods found in possible source areas suggests that most colonization of the island by these animals has been via the Benguela Current. Possible western Atlantic faunal contributions are significantly lower than for other marine taxa that have been studied at Ascension, all of which are generally characterized by having dispersive larval stages. The high proportion of apparently endemic species, which exceeds that described for amphipods of other oceanic islands, is probably due to both the island's isolation and incomplete faunal surveys in possible source areas. Amphipod species diversity is low, a probable consequence of the size, isolation, youth and low habitat variability of Ascension Is. Consistent with other Atlantic islands that have been studied, nestlers predominate (56% of the species), with tubicolous species (33%) of secondary importance and inquilines (11%) making only a minor contribution. Three species occur in the anchialine pool habitat. Rather unexpectedly, caprellid amphipods are absent.     

A new South American genus and species in the amaryllidid group of lysianassoid Amphipoda

Erikus dahli, a new genus and species in the amaryllidid group of lysianassoid amphipods, is described and illustrated from South American material.     

《韩国文集丛刊》中悲秋赋探析

在中国古代文学三大时间悲情模式中，悲秋是其中一个历史悠久的主题，并在韩国得到了继承和发展。《韩国文集丛刊》中的悲秋赋进一步拓展了悲秋在文学上的演绎，文化上的异质使悲秋这一主题在异国的文学中开出了璀璨的花朵。     

南大西洋至几内亚湾冬季海浪传播特性

为解决南大西洋至几内亚湾海域的海浪组成成分、传播特性及来源这3个该海域一直需要解决的问题，建立SWAN （Simulating WAves Nearshore）双层嵌套海浪模型对南大西洋至几内亚湾冬季海浪时空分布进行模拟分析，结果表明：南大西洋海浪有效波高呈高纬度区（30°S以南）向低纬度区（30°S以北）递减的趋势 ，高纬度区海浪传播方向与风场关系密切，低纬度区则与风场差异明显；南大西洋涌浪波高与混合浪波高分布高度相关，涌浪在混合浪中所占比例较大，尤其在风速较小的低纬度海域更为显著；南大西洋中部至几内亚湾存在相对固定的S-SW涌浪系统，其能量在二维海浪谱上分布集中，空间方向上分布范围较窄；模拟时段内几内亚湾呈明显的涌浪主导状态，通过对有效波高最大时刻的一次涌浪过程溯源发现，影响几内亚湾的涌浪可追溯至约6.5天前南大西洋咆哮西风带海域的强风浪。     

黔南石炭系层序地层格架中碳酸盐岩成岩作用研究

在三级层序地层格架内,从体系域及层序界面的角度对黔南石炭系碳酸盐岩的成岩作用进行了研究.结果表明,与LST有关的成岩作用主要为范围广泛的暴露溶蚀作用;与TST有关的成岩作用主要发育于海底成岩环境和混合水成岩环境,其中后者会随着海平面的不断上升而向大陆迁移;与HST有关的成岩作用主要包括发育于海底成岩环境的胶结作用及高位晚期的大气淡水成岩环境中的溶蚀、胶结和白云石化作用.与Ⅰ型层序界面有关的成岩作用主要有溶蚀作用、胶结作用和白云石化作用,成岩时间长、强度大,并且在黔南可进行区域对比;与Ⅱ型层序界面相关的成岩作用发育规模小,对碳酸盐岩的改造能力较弱.与HST有关的成岩作用及与Ⅰ型层序界面有关的成岩作用对碳酸盐岩储层的改造能力强,往往可形成厚层的白云岩及规模较大的溶蚀孔洞体系,因此,可以作为有利储层追踪对比及预测的有力地质依据之一.