伶仃洋东岸晚更新世以来硅藻组合及环境意义

通过分析伶仃洋东岸sz17QZ-20-3钻孔硅藻分布特征,结合测年、岩性和粒度,重建了该地区晚更新世以来的古环境演化。依据沉积物岩性粒度变化判断,晚更新世时期在23.6~11.0 m层段发育了一套河床相-溺古湾相-岸滩相-冲积相的垂向沉积序列,在花斑黏土层中有海水种Ethmodiscus rex碎片的存在,指示晚更新世海侵海退旋回。早全新世海侵在9000 cal.aBP左右到达研究区,海水种硅藻含量开始迅速增加,发育滨海平原相沉积;在8000 cal.aBP左右达到最高海平面,海水种硅藻含量最高;随后研究区处于海平面停滞状态,并缓慢下降,发育浅海相沉积;中晚全新世4.2~0 m层段为海退时期,发育河口湾相沉积。中全新世4.4~4.2 m层位海水种含量突然增加和4.4~4.6 m层位贝壳碎屑层指示可能有风暴潮事件发生;晚全新世0.3~0 m层段表层沉积物中硅藻丰度异常偏高,受人类活动影响较大。     

渤海湾北岸距今2000年的海面波动

天津以东,宝坻、丰南县城向南直至海边的低洼平原,其沉积相表明全新世中期以来始终是个滨海湿地环境,分布有宽阔平坦的淤泥质海滩。它和滦河三角洲砂质平原共同构成渤海湾北岸的海岸带。全新世以来,海平面逐渐上升,至全新世中期,大约距今6000多年海进曾到达最大范围,淹没海拔4米多的高程。嗣后,稳定海面逐渐退落。到距今2000年左右,早已成陆的滨海平原再次受海水入侵,使多处较大规模的高2.5-3米以上的战国至西汉文化遗存被海积物覆盖,或使3000年前的陆相草炭和粘土层被海岸沙堤(沙丘)超覆沉积。     

深沪湾末次冰期以来的地层结构及古环境演变

通过深沪湾高分辨率浅地层剖面声学地层和地质钻孔沉积地层的对比,并结合沉积物的粒度、微体古生物以及AMS14C测年的综合分析,揭示了研究区晚更新世末次冰期以来的地层层序,探讨了深沪湾的古环境演变。深沪湾高分辨率浅地层剖面自上而下划分的5个声学地层单元与钻孔岩芯划分的5个沉积地层单元具有较好的对应关系。8.2 ka BP左右,全新世海侵使得海水进入深沪湾海域,海平面低于现今海平面10~12 m,气候凉爽;7 ka BP左右海水到达现今海平面位置,并于6 ka BP左右到达最高,约比现今海平面高2~3 m,气候温暖湿润,这一时期,近岸大量裸子植物被海水淹没并被沉积物快速掩埋;5 850~5 642 a BP研究区温度降低,该降温活动持续到2 ka BP左右,气候凉爽干燥;2 ka BP以来温度逐渐上升,600 a BP左右有一个相对冷期,之后温度又逐渐上升至现今水平。     

青岛沿海地区20,000年以来的古地理环境演变

本文通过微体古生物和孢粉分析,岩相古地理研究和海岸地貌调查资料,探讨了青岛沿海地区20,000年以来的海陆变迁和古植被古气候的演变规律。在距今12,000—11,000年前,由于气候转暖,全新世陆架海侵使晚更新世末期的平原和盆地变成浅海和海湾。8000—5000年前出现高海面,5m等高线构成全新世海侵最大范围的古海岸线。自3500年以来,气温降低,海面逐渐下降至现代海岸线附近。     

北部湾广西沿岸全新世海侵过程的区域差异

通过分析北部湾广西沿岸3个地质钻孔的岩性、地球化学和有孔虫含量特征,确定了其沉积相序,在统一的高程坐标内,对各钻地层中沉积相的高程和年代进行了对比,分析了该区全新世以来海侵过程的区域差异;并以东亚全新世海平面波动曲线作为参照,估算了广西沿岸各主要海湾的构造沉降速度。研究表明:全新世以来,广西沿岸的海侵开始时间并不一致,这是由于各海湾构造沉降运动的区域差异造成的,东部的廉州湾构造基本稳定,而廉州湾以西则经历了较大幅度的构造沉降。构造沉降又导致了海平面波动过程的区域差异,进而影响到了地层形成,如海陆过度相沉积只发育于廉州湾以西遭受海侵时间较晚、相对海平面上升速度较低的区域。     

尼罗河三角洲全新世海平面变动及其对环境的影响——与长江三角洲的对比

利用泥炭(33个)和潟湖(65个)14C测年数据重建了尼罗河三角洲全新世海平面的变动过程,结果显示潟湖样品比泥炭更为有效地反映出海平面变动特征:距今7000a时海平面约位于现今-10m,距今5000a时约为-5m,距离2000a时已接近现代.海侵强度和范围受古地貌和区域沉降的影响呈现出东北部大、中部其次、西部最小.随着海平面上升速率减小,三角洲在约距今7000a时开始建造,并广泛发育潟湖、沙坝和平原河流沉积体系.此后,海平面趋于稳定,人类活动增强,导致海岸沉积环境大片萎缩、消亡.同样利用泥炭(45个)测年数据重建了长江三角洲全新世海平面变动,结果与尼罗河的差异较大,可能是两地沉降差异所致.近代长江三角洲人类活动也是导致环境退化的主要原因.     

青岛沿海地区地下卤水资源的开发和利用

青岛近海海岸区只有全新世海侵期,具备成卤古海水来源,近海海岸平原狭小,第四系沉积层浅薄,既有封闭环境优良的湾中湾和堰坝式沉积盆地提供聚卤场所,又有滨海第四纪沉积盆地地质基础以及入海径流贫乏的有利条件,为地下卤水形成和富集创造了有利环境。海岸地貌特点控制了卤水分布区呈斑块状散布,局部岸段可形成小型矿带。具有地下卤水的开发和利用的良好条件。     

盐城市境内全新世以来的海陆变迁

盐城市地处黄海之滨,全新世以来,经历了陆地—海洋—陆地这一海陆演变过程。早全新世,本区受到海侵影响,但仍以陆地为主。中全新世,海侵达到高峰,本区为浅海环境,形成了纵贯南北的岸外沙堤。晚全新世,河流堆积作用增强,境内东部海岸东迁,形成了滨海平原及废黄河三角洲;西部泻湖区则淤积为里下河平原。     

青岛港湾海岸地区第四纪地下卤水生存环境与富集条件

青岛港湾海岸发现可利用卤水资源是中国北方沿海第四纪滨相地下卤水研究的又一次重要进展，青岛港湾海岸区只有全新世海侵期，具备成卤古海水来源，虽然海岸平原狭小，第四系沉积层浅薄，却有封闭环境优良的湾中湾和堰坝式沉积盆地提供聚卤场所，又有滨海第四纪沉积盆地地质基础以及入海径流贫乏的水文条件，为地下卤水形成和富集创造了有利环境。港湾海岸区海岸地貌特点控制了卤水分布区呈斑块状散布，局部岸段可形成小型矿带，青岛     

渤海湾西岸全新世以来沉积物地球化学与黏土矿物特征及其对环境和气候的响应

通过对渤海湾西岸BXZK11孔沉积物黏土矿物、地球化学元素组分、粒度分析以及AMS14C年代测定并与研究区周边6个具有较好年龄控制的钻孔剖面对比,结合黏土矿物蒙脱石/(伊利石+绿泥石)比值以及元素Al/Si和Al/Na比值对气候变化的响应,探讨了渤海湾西岸地区全新世以来沉积环境以及气候变化过程。结果表明,末次盛冰期到8830 cal.aBP,海平面快速上升,海水临近研究区,沉积物以黄河古河道沉积为主,气候温凉略湿;8830~6255 cal.aBP,海侵范围达到最大,研究区主要为潮坪-浅海环境,气候温暖湿润;6255~3650 cal.aBP,海平面逐渐降低,沉积环境为前三角洲沉积,沉积物为黄河三角洲的一期超级叶瓣,气候转为温凉稍湿;3650~2780 cal.aBP,海平面趋于稳定,三角洲不断进积,为三角洲前缘环境,气候向凉干方向变化;2780 cal.aBP至今,古黄河三角洲不断进积,该区变成三角洲平原环境,气候凉干与现今相似。     

Trends in the variation of the sea level in the lagoons of the Southeastern Baltic

This paper analyses the global tendency of the sea level rise (SLR) and its long term influence on the sea level upstream drainage cascade based on the example of the level’s variation in the Vistula Lagoon of the Baltic Sea compared to the other lagoons and coastal regions of the southeastern part of the Baltic Sea. A steady positive trend in the water level variations was revealed; its magnitude varies significantly depending on the time period. In general, during the 100–150 year period, the rate of the SLR in the lagoons and coastal areas of the Baltic Sea (1.7–1.8 mm per year) is close to the SLR rate in the World Ocean. In the second half of the 20th century, the increased rate of the SLR in the lagoons and marine areas became stronger (up to 3.6 mm per year in the Vistula Lagoon and in 1959–2006 in the sea and exceeded the rate of global ocean SLR). It dramatically increased at the end of the last century both in the lagoons and in the sea (up to 10.0–15.0 mm per year). This is the response not only to the global climate warming but it is likely that it is also a response to the changes of the climate driving forces that influence the regimes of the local wind and precipitation in the catchment.     

Distribution of Pacific-origin water in the region of the Chukchi Plateau in the Arctic Ocean in the summer of 2003

1Introduction Besidestheprecipitationandriverdischarges,the watersinthePacificOceanandtheAtlanticOceanare thesourcesoftheArcticOceanwater.TheAtlantic waterenterstheArcticOceanviatheFramStraitand theBarentsSea.Foritsdenserfeatureduetohigh salinity,mostofitsinkstothenorthofSvaldbardand circulatesinallthedeepbasinsintheArcticOcean, formingthedeepandbottomwatersoftheArcticO- cean(Aagaardetal.,1985;Rudelsetal.,1999).The BeringStraitistheonlychannelforthePacificwater toflowintotheArcticOce…     

鄂霍茨克海北部沉积盆地的含油气层系

1 古新-下渐新统含油气层系 古新-始新统母岩形成于滨海和湖泊沉积环境中,并在大量冲积源的参与之下,促进了含分散有机质混合类型砂-黏土质陆源岩层的堆积。在中国东北诸盆地中,含工业油气的白垩-早第三纪建造形成于开阔的浅水和深水湖泊环境中。与中国的盆地类似,在下第三系下部     

Variations in the Kinematics of Deformation in the Vicinity of the Catastrophic Sumatra Earthquake

Izvestiya, Atmospheric and Oceanic Physics - The Great Andaman–Sumatra earthquake (GASE) on December 26, 2004, with magnitude Mw of 9.2, occurred in the Indian Ocean near the northwestern...     

Peculiarities in the distribution of hydrocarbons in the southeastern part of the Baltic Sea

Data on the contents and compositions of the hydrocarbons (HCs)—aliphatic (AHCs) and polycyclic aromatic (PAHs)—are provided in comparison with the contents of the total organic carbon (C_org), the lipids in the particulates, and the C_org in bottom sediments. Particular attention has been paid to the distribution of the HCs in the water area of the Kravtsov oil field. It has been established that the concentrations of AHCs in the water are governed by the content of particulates, and the elevated AHC concentrations are confined to the coastal areas. In the water area of platform D-6, the sandy bottom sediments were notable for the great variability of the HC concentrations, both laterally and from year to year. In the summer of 2010, the content of AHCs averaged 40 μg/g (19% in the C_org), and that of PAHs, 23 ng/g. Natural seepage from the sediment mass is considered to be a source of HCs along with oil contamination.     

Relationship between the path of the Kuroshio in the south of Japan and the path of the Kuroshio Extension in the east

A relationship between paths of the Kuroshio and Kuroshio Extension (KE) is investigated, using the satellite-derived altimetry dataset of 1993–2008. When the Kuroshio takes the nearshore nonlarge meander path or typical large meander path and resultantly goes through the deeper channel (about 2500 m) of the Izu-Ogasawara Ridge, the KE path adopts a relatively stable state with the two quasi-stationary meanders. On the other hand, when the Kuroshio takes the offshore nonlarge meander path and then passes over the shallower part of the Ridge (about 1000 m), the KE path tends to be convoluted, i.e., an unstable state.     

Causes of the bottom hypoxia in the eastern part of the Gulf of Finland in the baltic sea

The data on the bottom concentrations of dissolved oxygen in the eastern part of the Gulf of Finland obtained in 1923–1939 and in 1962–1989 were analyzed. No statistically reliable differences were found between the two periods studied. It was found that, during the 20th century, the fluctuations in the oxygen concentration were caused by the interannual variability of the winter severity and water salinity. A strong oxygen deficit in the summer was recorded after cold winters, when early freezing suppressed the vertical mixing, and/or in the years of a significant inflow of salt waters from the Baltic Sea with low oxygen contents. It is likely that the long-term dynamics of the oxygen concentration near the bottom in the open parts of the bay is determined by the large-scale variability of the hydrometeorological parameters.     

Role of the small-size fraction of mesozooplankton in the pelagic community of the northeastern part of the Black Sea in the autumn

The role of the small-size (SF; 0.1–0.5 mm) and large-size (LF; 0.5–20.0 mm) fractions in the biomass and abundance of mesozooplankton (0.1–20.0 mm) was assessed using the database of samples obtained during the cruises of RV Akvanavt in the northeastern Black Sea in November 2000 and October 2006. The mesozooplankton was collected by means of Juday nets (37/50, filtering gauze 160 μm) and Niskin bottles in two areas: (1) the shelf and continental slope (30–1480 m depth) and (2) the deep sea (depths of more than 1500 m). The plankton net was considerably less effective in collecting the SF of the mesozooplankton (by a factor of 30–36) than the Niskin bottles. When comparing the SF and LF, we estimated the abundance and biomass of the SF in the samples obtained with the Niskin bottles. The abundance of the SF in the deep-sea area was 2.5 times lower compared to the shelf and continental slope, and the LF abundance was 5.0 times lower in the same way. The abundance of the SF constituted 88% of the total mesozooplankton on the shelf and continental slope, and 78% in the deep-sea area. The biomass of the SF was higher as well on the shelf and continental slope. Meroplankton played a significant role in the SF zooplankton abundance (0.5 × 10³ + 0.16 ind. m⁻³) in this area. The SF grazing impact was 10% of the total mesozooplankton grazing on the shelf and continental slope, and 17% in the deepsea area. Appendicularia and nauplii of copepods had the greatest contribution to the mesozooplankton grazing among the SF group.     

Features of the distributions of the transparency and particulate matter content in the surface water layer in the northwestern part of the Black Sea in the autumn period

Using the data of long-term simultaneous optical, biological, and hydrological observations (1980–1993), particular features of the horizontal distribution of the transparency and the total particulate matter content and the contents of its organic components (organic carbon and nitrogen and chlorophyll a) and their variability in the surface water layer (0–5m) over the northwestern shelf and the adjacent abyssal part of the Black Sea in the autumn season are considered. The detritus/phytoplankton ratio in the particulate organic matter and their relative contents in the total particulate matter are calculated. The distributions of the transparency and particulate matter content were found to be in good agreement and both depend on the water dynamics. It was established that, during the period of the abrupt growth in the Black Sea water turbidity (in the early 1990s), a significant decrease in the transparency and an increase in the particulate matter content caused by the production-destruction processes were observed only in the central and southern regions of the sea.