Genetic Structure and Haplotype Pattern of Marine Planktonic Ostracod (Porroecia spinirostris) from South China Sea Based on Mitochondrial COI Gene

Ocean Science Journal - Ostracods (Crustacea, Ostracoda) are small bivalved crustaceans, contributing to the marine zooplankton community. They are widely distributed and are relatively abundant...     

Gravitational Waves and Gravitational-wave Sourcestwo

The recent discovery of gravitational-wave burst GW150914 marks the coming of a new era of gravitational-wave astronomy, which provides a new window to study the physics of strong gravitational field, extremely massive stars, extremely high energy processes, and extremely early universe. In this article, we introduce the basic characters of gravitational waves in the Einstein's general relativity, their observational effects and main generation mechanisms, including the rotation of neutron stars, evolution of binary systems, and spontaneous generation in the inflation universe. Different sources produce the gravitational waves at quite different frequencies, which can be detected by different methods. In the lowest frequency range (f < 10^?15 Hz), the detection is mainly dependent of the observation of B-mode polarization of cosmic microwave background radiation. In the middle frequency range (10^?9 < f < 10^?6 Hz), the gravitational waves are detected by analyzing the timing residuals of millisecond pulsars. And in the high frequency range (10 ? 4 < f < 10⁴ Hz), they can be detected by the space-based and ground-based laser interferometers. In particular, we focus on the main features, detection methods, detection status, and the future prospects for several important sources, including the continuous sources (e.g., the spinning neutron stars, and stable binary systems), the burst sources (e.g., the supernovae, and the merge of binary system), and the stochastic backgrounds generated by the astrophysical and cosmological process. In addition, we forecast the potential breakthroughs in gravitational-wave astronomy in the near future, and the Chinese projects which might involve in these discoveries.     

Changes in air temperature over China in response to the recent global warming hiatus

The 1998-2012 global warming hiatus has aroused great public interest over the past several years. Based on the air temperature measurements from 622 meteorological stations in China, the temperature response to the global warming hiatus was analyzed at national and regional scales. We found that air temperature changed -0.221℃/10a during 1998-2012, which was lower than the long-term trend for 1960-1998 by 0.427℃/10a. Therefore, the warming hiatus in China was more pronounced than the global mean. Winter played a dominant role in the nationwide warming hiatus, contributing 74.13%, while summer contributed the least among the four seasons. Furthermore, the warming hiatus was spatial heterogeneous across different climate conditions in China. Comparing the three geographic zones, the monsoon region of eastern China, arid region of northwestern China, and high frigid region of the Tibetan Plateau, there was significant cooling in eastern and northwestern China. In eastern China, which contributed 53.79%, the trend magnitudes were 0.896℃/10a in winter and 0.134℃/10a in summer. In the Tibetan Plateau, air temperature increased by 0.204℃/10a, indicating a lack of a significant warming hiatus. More broadly, the warming hiatus in China may have been associated with the negative phase of PDO and reduction in sunspot numbers and total solar radiation. Finally, although a warming hiatus occurred in China from 1998 to 2012, air temperature rapidly increased after 2012 and will likely to continuously warm in the next few years.     

Quantifying the spatial heterogeneity of points

Variation in the spatial heterogeneity of points reflects the evolutionary process or mechanism of geographical events. The key to depicting this variation is quantifying spatial heterogeneity. In this paper, the spatial heterogeneity of a point pattern is defined as the degree of aggregation-type deviation from complete spatial randomness. In such a case, a goodness-of-fit-type statistic based on the distribution of nearest-neighbor distances called the level of heterogeneity (LH*) is regarded as a standard measurement, and a normalized version called the normalized level of heterogeneity (NLH*) is proposed for datasets with different point numbers and study region areas. Considering the complex integration calculation of LH* and NLH*, simulation experiments are implemented to test the capability of some classic nearest-neighbor statistics in quantifying spatial heterogeneity. The results showed that except for the standard LH* statistic, only Clark and Evans’ statistic (A-w) and Byth and Ripley’s statistic (H-xw) are robust. Statistics NLH*, (A-w) and (H-xw) are validated by quantifying the spatial heterogeneity of two-dimensional crime events, three-dimensional earthquake events and four-dimensional origin-destination (OD) events. The results indicate that these statistics all have a reasonable explanation in quantifying spatial heterogeneity for real-world geographical events of different types and with different dimensions. Compared with NLH*, Clark and Evans’ (A-w) statistic and Byth and Ripley’s (H-xw) statistic are recommended from the perspective of accessibility.     

藻源性有机质对高原深水湖泊沉积物矿化作用的激发效应

湖泊营养水平提升,浮游植物快速增殖,大量藻类碎屑沉降到沉积物表面。藻屑作为新生不稳定有机质,对湖泊沉积物有机质(SOM)产生激发效应,影响湖泊沉积物碳循环过程。本文以深水湖泊抚仙湖南湖心沉积物为研究对象,采用优势种水华束丝藻(Aphanizomenon flos-aquae),进行不同浓度藻屑添加(×1倍组、×5倍组和×10倍组)的培养实验。应用碳同位素在线监测仪,探究藻屑添加对于SOM矿化作用的激发效应并预测可能产生的环境效应。结果表明：(1)添加的藻屑对上覆水和间隙水发光性溶解性有机质(CDOM)组成和性质产生影响,前期CDOM中类蛋白组分含量显著增加,但后期CDOM腐殖化程度升高。同时,藻屑的添加使二氧化碳(CO₂)释放量增大,蛋白酶活性和转化酶活性增强;(2)3个不同浓度的藻屑添加组均检测到不同程度激发效应,其中×1倍组和×5倍组对SOM矿化过程前期体现为正激发效应,最大值分别达到(12.18±0.65)和(26.60±9.14)μg/(mL ws),后期两个组别都转为负激发效应;×10倍组则在整个实验过程中均表现为负激发效应;(3)藻屑的添加使得间隙水易...     

Characteristics of Carbonate Reservoir and Its Forming Conditions in Continental Lake Basin of China

For decades of exploration, geologists have made great achievements in the exploration of lacustrine carbonate rocks. By dissecting four typical cases of lacustrine carbonate rocks, such as Lucaogou Formation of Permian in Junggar Basin, Da'anzhai Section of Jurassic in Sichuan Basin, Cretaceous in Yin'e Basin and Oligocene in Qaidam Basin, the reservoir characteristics, hydrocarbon generating capacity and reservoir forming model of source rocks were analyzed. The results show that: \mathrm{①} Lacustrine carbonate reservoirs are generally dense, with nano-micron reservoir space as the main reservoir space, including dolomite intergranular pore, organism cavity and accumulation pore, micro-fracture system and its corrosion expansion pore. Saline environment is beneficial to dolomitization and can improve the reservoir capacity of lacustrine carbonate rocks, but most of the permeability is less than 0.1 mD. \mathrm{②} Lacustrine carbonate rocks have not only reservoir capacity, but also can be used as source rocks. The abundance of organic matter is not high and the maturity is generally low. However, dispersed soluble organic matter in source rocks can generate and expel hydrocarbons in large quantities at low maturity stage, which has high liquid hydrocarbon yield. \mathrm{③} Oil and gas reservoirs are characterized by "high initial production, large reduction of production and long-term low and stable production", and are typical "fracture-pore" reservoirs. Fracture networks provide migration pathways in the process of primary migration and accumulation of oil and gas in geological history and oil and gas exploitation nowadays. \mathrm{④} Oil and gas reservoirs are "continuous" unconventional reservoirs, which often form regional oil and gas field groups together with conventional reservoirs in adjacent areas. The research results lay a theoretical foundation for re-evaluating the exploration potential of lacustrine carbonate rocks.     

贵州震旦系陡山沱组磷块岩成磷作用及与新元古代末期氧化事件(NOE)的耦合*

新元古代末期历经“雪球地球”和大气、海洋增氧事件后,发生了全球性成磷事件,贵州省震旦系陡山沱组大规模磷矿床沉积是本次成磷事件的典型代表。然而现阶段对贵州陡山沱组磷块岩成磷作用机制研究存在诸多争议,成磷事件与同期古海洋环境转变之间的关联研究也较为薄弱。作者以贵州省瓮安、遵义和丹寨地区陡山沱组原生磷块岩为研究对象开展的沉积学、岩石学、矿物学和地球化学特征研究表明: 陡山沱早期成磷作用被限制在浅水海岸,瓮安地区A矿层球粒磷块岩中大量的含铁自生矿物黄铁矿、海绿石以及无Ce负异常指示的贫氧沉积水体环境均表明,Fe-氧化还原泵成磷模式在富磷过程中发挥了重要作用;陡山沱晚期磷块岩分布扩散至较深水陆棚—斜坡沉积相区,磷块岩与富有机质岩层共生,矿物晶体形态特征与矿石内富含的大量生物化石均表明,有机质沉降聚磷作用和生物成磷作用促使磷块岩大量沉积,较明显的Ce负异常值也指示了海水氧气含量的提升。成磷作用模式的转变和磷块岩分布的扩展是对海洋增氧事件的沉积响应,同时造成的多细胞动物演化也影响了深部水体的氧化还原状态,进而反映了贵州省陡山沱组磷块岩大规模沉积与新元古代末期氧化事件(NOE)密切的耦合关系。     

植硅体记录的敦化北部山地近2 ka泥炭沼泽演化气候背景

对敦化北部山地205 cm深泥炭剖面中的植硅体进行提取、鉴定和分析,结合AMS¹⁴C测年,重建研究区近2 ka的古气候环境过程,探讨其变化规律及影响因素。植硅体组合、有序聚类和植硅体指数变化趋势显示,研究区泥炭沼泽经历了4个显著阶段：即45-680 A.D.暖湿阶段;680-1340 A.D.温暖偏干阶段;1340-1870 A.D.由干转湿的寒冷阶段;1870-2017 A.D.转暖、干湿波动阶段。其中,680-1225 A.D.对应中世纪暖期（MWP）,1340-1870 A.D.对应小冰期（LIA）。在此气候变化背景下,泥炭沼泽发展经历了由缓慢逐渐加快的过程。对比太阳辐射和太阳活动的变化、石笋δ¹⁸O序列、重建的东北地区古温度以及Niño3.4重建曲线,泥炭剖面的植硅体分析显示MWP和LIA期间的古气候过程受到太阳活动、太阳辐射、季风环流和ENSO（El Niño-Southern Oscillation）的控制。     

山东峡山湖东岸现代滩坝沉积模式及控制因素*

滩坝作为发育于滨岸带非常重要的沉积储集层类型之一,已成为隐蔽油气藏勘探的目标。为进一步明确峡山湖东岸滨浅湖滩坝沉积模式,以现代沉积考察为基础,结合探地雷达技术和粒度分析资料,对东岸研究区滩坝砂体的沉积特征以及控制因素进行详细分析。结果表明: 峡山湖东岸主要发育风成沙丘及滩坝2种沉积体系。早期风成沉积物以发育连续性好的大型板状交错层理细砂为主,分选较好,粒度概率曲线以两段式为特征;滩坝沉积物以发育连续性差的板状交错层理、平行层理中砂为主,主要为反粒序或者复合粒序,具冲刷构造,岩性较混杂并以砂泥薄互层为特征,发育大量植物根系,粒度概率曲线以三段式为主,跳跃组分分为2段,分选较好。探地雷达资料表明研究区下部主要以厚层层状反射结构砂体为主,与风成沙丘沉积反射特征较为一致,环境敏感粒度组分对滩坝沉积较强的水动力作用有较好的指示。总体上,风力作用控制了风成砂体的沉积发育并且改变了古地貌条件,风浪作用冲刷改造了早期砂体,为滩坝的发育提供了物源,控制了滩坝发育的规模和地理位置,可概括为“风运—湖改”滩坝沉积模式,可为滩坝体系的识别和有利储集层预测提供指导。     

胶东谢家沟金矿床蚀变钾长石40Ar-39Ar年龄及地质意义

谢家沟金矿床位于胶西北焦家断裂带和招平断裂带之间。在系统观察坑道各类蚀变现象的基础上,发现围岩蚀变主要有钾长石化、硅化、黄铁矿化、绢云母化,其次可见绿泥石化和碳酸盐化等;基于蚀变的叠加和穿插关系查明了不同阶段的主要热液作用记录,从早到晚依次为钾长石化、黄铁绢英岩化、陡立石英硫化物细脉;蚀变具有明显的空间分带现象,从中心到两侧分别为陡立石英硫化物细脉带、黄铁绢英岩化带、钾长石化带。本次研究对蚀变钾长石开展了⁴⁰Ar-³⁹Ar精细测年工作,获得的坪年龄为（112.79±0.62）Ma（MSWD=5.76）,与等时线年龄（（115.56±1.72）Ma（MSWD=4.59））一致,限定了谢家沟金矿床的钾化蚀变年龄,与胶东地区获得的金成矿事件年龄相近,说明谢家沟金矿床与胶东地区金矿床是在同一成矿-热事件下形成的。结合区域岩浆演化特征,胶东地区在郭家岭岩体形成之后、在（120±10）Ma还存在一期与金成矿关系密切的岩浆活动。