雷州半岛湛江组红树孢粉组合的发现及其意义

雷州半岛的第四纪沉积,为早更新世的湛江组、中更新世的北海组、晚更新世的湖光岩组,该区以湛江组沉积厚度最大且典型.     

唐山祥云湾海洋牧场海域网采浮游植物群集特征研究

为研究唐山祥云湾海洋牧场海域网采浮游植物群集特征, 于2020年11月至2021年11月在祥云湾海洋牧场海域进行了浮游植物及环境因子的周年逐月调查。共鉴定浮游植物41属78种, 其中硅藻33属62种, 甲藻7属15种, 硅鞭藻1属1种, 年均丰度为205.58×10⁴ cells/m³, 多样性指数H''为2.88。与近岸非增殖海域不同, 该海域浮游植物的丰度及群落结构指数在春夏季水生生物繁生期达到全年最低。优势类群的季节演替明显, 其中, 3~5月以诺氏海链藻最占优势, 9~10月以角毛藻和中肋骨条藻最占优势, 周年优势类群以圆筛藻和角毛藻最占优势, 其优势度变动在6月前以圆筛藻显著为高, 之后则以角毛藻显著为高; 此外,甲藻的优势度在泛冬季(11~2月)达到最高。鱼礁区与对照区的对比结果显示, 两区域浮游植物的群落变化均可划分为泛冬季低温期(11~2月)、春夏季繁生期(3~6月)、泛秋季降温期(7~11月)三个时期。链状浮游植物的丰度在礁区明显高于对照区, 而非链状浮游植物则相反; 与生物作用关系密切的溶解有机碳、pH值在礁区低于对照区, 而总磷和溶解态硅则相反。Pearson相关及冗余分析(RDA)显示, 两区域浮游植物与环境因子的显著相关关系在不同时期差异明显。春夏季繁生期牡蛎礁上的贝类滤食活跃, 浮游植物与环境因子的关系最为密切, 浮游植物与环境因子的相关关系达到显著水平的数量最多。礁区与对照区浮游植物的群集特征差异可能受到礁体附着生物活动及潮汐往复流混合作用的影响。     

柴达本盆地沙下盐湖的卤水化学及矿物沉积特征——以察尔汗盐湖区北部外围地带为例

对柴达木盆地察尔汗盐湖区外围沙下盐湖的卤水及沉积进行了综合研究。沙下盐湖卤水化学组成与地表径流和开放性盐湖卤水之间存在明显的差异性,具有高Na⁺+Cl^-、低Mg²⁺+Ca²⁺+SO₄^2-、贫K⁺+CO₃^2-+HCO₃^-等特征。沙下盐湖析盐层位含有新生矿物并夹带碎屑矿物,其盐类矿物组合为:石盐+羟氯镁铝石+光卤石。25℃等温蒸发相图表明,其卤水演化方向往光卤石析出区迁移,在穿越上覆盖层通道中卤水发生的物理化学反应与独特的沉积特征,可以作为继续寻找沙下盐湖的指导。     

白令海北部陆坡晚第四纪的古海洋与古气候学记录

白令海北部陆坡B2 9柱状样中放射虫Cycladophoradavisiana含量曲线和深海SPECMAP氧同位素记录的对比 ,为该柱状样建立了晚第四纪约 1 0万年以来的地层年代框架。该柱状样中微体化石、碳屑颗粒、筏冰碎屑 (石英和岩屑颗粒 )的定量分析结果表明 ,作为表层生产力指标的粗组份自氧同位素 5 .3期以来呈阶梯状增加 ,反映表层生产力阶段式的增长 ;碳屑颗粒丰度自氧同位素 5 .3期至末次冰消期的增加说明白令海末次冰消期以前气候较全新世干冷 ,天然火灾发生的概率较全新世大大增加 ;冰期和早、中全新世较高的筏冰碎屑反映了冰期和早、中全新世白令海陆架海冰的扩大以及气候转暖所导致的海冰消融的过程 ,揭示了白令海对过去全球气候变化的响应。     

Petrography of Late Cambrian to Middle Ordovician radiolarian chert in Kazakhstan with special reference to the emergence of benthic animals in the pelagic realm

Upper Cambrian to Middle Ordovician radiolarian chert successions from Kazakhstan were studied to clarify the history of the emergence of benthic animals in ocean floor sediments. Radiolarian tests and clay were deposited for a period of 30 Myr without experiencing an influx of continent-derived coarse clastic materials. Red, grey and black cherts of the Upper Cambrian to the upper mid-Darriwilian are thinly laminated, and no trace of benthic animal activity is recognized in that time interval. Bioturbation structures and burrow traces in mid-Darriwilian stage red chert in Kazakhstan suggest that benthic animals colonized the location where radiolarian chert formed, but that there was a significant delay in colonization when compared with similar reported occurrences in Australia and Canada.     

Sequence stratigraphic framework and sedimentary model of Shanxi Formation in northeast Zhoukou Depression of the North China Plate

The sequence stratigraphic framework of Shanxi Formation in the northeast Zhoukou Depression was established based on detailed sequence stratigraphical and sedimentological analysis by utilizing the logging and core data of six wells drilled in the eastern tectonic unit of Zhoukou Depression. It was divided into three third-order sequences, namely SQs1, SQs2, and SQs3 from bottom to top. Each sequence can be divided into a transgressive system tract (TST) and a highstand system tract (HST). Furthermore, four sequence boundaries and three maximum flooding surfaces were identified, and they are the bottom interface SBs and maximum flooding surface mfss1 of SQs1, the bottom interface SBs1 and maximum flooding surface mfss2 of SQs2, the bottom interface SBs3 and maximum flooding surface mfss3 of SQs3, and the top interface SBx from bottom to top. Carbonate tidal flat –clastic tidal flat sedimentary system developed in Shanxi Formation in the northeast Zhoukou Depression (also referred to as the study area) under the control of regression. Meanwhile, four sedimentary microfacies were identified in the sedimentary system, which are lime-mud flats, sand flats, mixed flats, and mud flats. The transgression in the study area occurred from the southeast to the northwest. Therefore, the northwestern part is the seaward side, and the southeastern part is the landward side. As revealed by relevant drilling data, SQs1 of the Shanxi Formation is characterized by the development of limestone and carbonaceous mudstone, with limestone, dark mudstone, and carbonaceous mudstone mainly developing. Meanwhile, lime-mud flats were mainly deposited in it. During the periods of SQs2 and SQs3, the sedimentary environment of the study area changed from the carbonate tidal flats to clastic tidal flats as the coastline migrated towards the sea. In these periods, sand flats mainly developed near the maximum flooding surfaces and were relatively continuous in the eastern and southern parts of the transgressive system tract; mixed flats were relatively continuous in the western and northern parts of the transgressive system tract as well as the eastern and southern parts of the highstand system tract; mud flats widely developed in the highstand system tract. Peat flats mainly developed in the period of HSTs2, with coal seams relatively developing in the southeastern part of the study area as revealed by drilling data. The peat flats in SQs2 are favorable hydrocarbon source layers, the lime-mud flats in SQs1 and sand flats formed in the transgression periods of SQs2 and SQs3 constitute favorable hydrocarbon reservoirs, and the mud flats form in the transgressions periods serve as favorable cap rocks. Therefore, the study area features a reservoir-cap assemblage for self-generating and self-storing of hydrocarbon, and the southeastern part of the study area can be taken as a favorable exploration area.     

First evidence of Middle to Late Triassic radiolarians in the Garba mountains,South Sumatra,Indonesia

A Middle to Late Triassic (Ladinian–Carnian) radiolarian fauna was discovered in cherts of the Situlanglang Member of the Garba Formation, South Sumatra, which is generally regarded as of Late Jurassic–Early Cretaceous age. This fauna is characterized by the presence of Annulotriassocampe sulovensis, Triassocampe postdeweveri, Spongotortilispinus tortilis, Poulpus piabyx, Canoptum levis and others. This evidence possibly indicates that the deposition of the Situlanglang cherts took place after the collision of the Sibumasu and East Malaya blocks recorded in the Bentong–Raub Suture in Peninsular Malaysia in Late Permian–Early Triassic times. During the Middle–Late Triassic Sumatra and Peninsular Malaysia consisted of submarine horst and graben structures. It is possible that a submarine graben, the Tuhur basin, whose southern boundary was formerly undefined, extends into South Sumatra, to the area in which the Situlanglang cherts were deposited. The Situlanglang Member is proposed to be a rock unit stratigraphically contemporaneous with those of the Middle–Upper Triassic Kualu and Tuhur Formations in North and Central Sumatra.     

Radiolarian‐based study on the fabric and the formation process of the Early Cretaceous mélange near Zhongba,Yarlung–Tsangpo Suture Zone,southern Tibet

The Yarlung–Tsangpo Suture Zone (YTSZ), as the southernmost and youngest among the sutures that subdivides the Tibetan Plateau into several east–west trending blocks, marks where the Neo‐Tethys was consumed as the Indian continent moved northward and collided against the Eurasian continent. Mélanges in the YTSZ represent the remnants of the oceanic plate through subduction and collision. Mélanges are characterized by a highly sheared volcanoclastic or siliceous mudstone matrix including blocks of chert, claystone, and basalt. Detailed radiolarian analyses are conducted on the mélange near Zhongba County. Macroscopic, mesoscopic, and microscopic observations are combined in order to elucidate the relationships among age, lithology, and structure of blocks in the mélange. Reconstructed ocean plate stratigraphy includes Lower Jurassic limestone within the chert sequence accumulated at a depth near the CCD (Unit 2), Upper Jurassic thin‐bedded chert interbedded with claystone deposited in the wide ocean basin (Unit 3), and Lower Cretaceous chert with siliceous mudstone (Units 4 and 5), representing the middle parts of ocean plate stratigraphy. The results highlight the fabric of brecciated chert on mesoscopic scale, which is thought to be due to localized overpressure. The formation of mesoscopic and microscopic block‐in‐matrix fabrics in the mélange is proposed for the chert and siliceous mudstone bearing different extents of consolidation and competence during the progressive deformation of accreted sediments at shallow‐level subduction.     

黄河干流浮游植物群落特征及其对水质的指示作用

2008年5-6月和9-10月对黄河干流13个河段和4座水库的浮游植物群落及其环境进行了全面调查.共鉴定浮游植物8门83属150种,其中有硅藻59种,绿藻55种,蓝藻24种,甲藻4种,裸藻4种,金藻2种,黄藻1种和隐藻1种,平均细胞密度和生物量分别为126.90×104cells/L和0.940mg/L.从大的格局上看,浮游植物群落在种类数、种类组成和现存量上均存在较明显的空间分异,这种分异性可从河流流速、泥沙含量和受污染程度得到解释.根据浮游植物污染指示种和Shannon-Wiener多样性指数分析,黄河干流各河段多受到不同程度的污染.与1986年的资料相比,黄河干流浮游植物组成发生了明显变化,属数下降了9.8%,而平均生物量升高了128.7%,且在种类组成上也发生了明显的变化,表明河流污染程度的加剧.