生物碎屑灰岩差异成岩及储集层特征:以伊拉克HF油田白垩系Mishirif组为例*

中东地区白垩系Mishirif组以生物碎屑灰岩为主,其形成于温暖潮湿的环境中。综合利用岩心、铸体薄片、全岩分析、常规物性及高压压汞等资料,以伊拉克HF油田Mishrif组为例,开展生物碎屑类型、分布特征、差异成岩及储集层特征等研究。Mishrif组灰岩中生物碎屑以底栖有孔虫、非固着类双壳类、厚壳蛤和棘皮动物为主,含少量苔藓动物、藻类与海绵动物,其含量、类型及大小对沉积环境有重要指示意义。沉积环境决定岩石组分与结构的差异,在此基础上成岩作用控制岩石的孔隙结构与物性特征。生物碎屑主要经历了不同程度海水环境的泥晶化和生物钻孔、大气淡水环境的溶蚀和胶结、埋藏环境的压实压溶和颗粒破裂作用。以底栖有孔虫和非固着类双壳类碎屑为主的低能沉积环境具有“弱溶蚀、强胶结、强压实”的成岩特征,主要发育微孔、晶间孔及粒内孔,孔喉分布呈偏细态细微喉单峰型,物性较差;以厚壳蛤和棘皮动物碎屑为主的高能沉积环境具有“强溶蚀、弱胶结”的成岩特征,主要发育铸模孔、粒间孔及粒间溶孔,孔喉分布呈偏粗态中粗喉极宽峰型,是Mishrif组最有利储集层。以HF油田Mishrif组为代表的白垩系生物碎屑灰岩在中东地区发育广泛,故上述成果对于该地区生物碎屑灰岩油气开发具有重要意义。     

黑龙江省东部早古生代晨明组物源区特征及其构造背景

为揭示黑龙江省东部早古生代晨明组沉积物源区特征及其沉积构造背景,对晨明组进行了地球化学特征研究。结果表明：晨明组岩石样品化学蚀变指数（I_CA）值和斜长石蚀变指数（I_PA）值较低、成分变异指数（I_CV）值中等偏高,指示晨明组沉积物来源于不成熟的物质源区,并经历了较弱的化学风化作用和活动构造背景下的初次循环;LREE富集、HREE稳定和明显的负Eu异常,指示沉积物源区物质具有明显的上地壳特征且沉积物源岩为长英质火成岩;主量、微量和稀土元素特征共同指示晨明组形成于活动大陆边缘环境或大陆岛弧环境。结合前人研究成果,判定晨明组沉积物来源于经历了弱-中等程度化学风化作用的早古生代花岗质岩,沉积构造背景可能为靠近大陆岛弧的活动大陆边缘环境。     

文蛤亮氨酸氨肽酶LAP3的基因克隆及其在幼体不同发育时期、成体不同组织的表达分析

为探索贝类LAP3基因的结构和功能特征以及在生长发育过程中的作用,利用cDNA末端快速扩增（RACE）法获得文蛤LAP3（Mm-LAP3）基因的cDNA全长序列,并对其生物信息学、组织及发育时期表达特征进行了分析。结果显示,Mm-LAP3基因cDNA全长2 037 bp,ORF区1 254 bp,编码417个氨基酸;Mm-LAP3蛋白由Peptidase_M17超家族序列的N-端结构域和Peptidase_M17催化结构域组成。荧光实时定量PCR结果表明,Mm-LAP3基因在文蛤成体6个组织和幼体10个发育时期中均有表达,其中在斧足中的表达量显著高于其他组织（P<0.05）,这与斧足蛋白含量丰富、代谢旺盛相关;在幼体10个发育时期中的表达量呈现逐渐升高的趋势,在D形幼虫时期达到最高,随后又有所降低,推测Mm-LAP3基因在早期发育时期参与了某些组织器官的形成。     

鸭绿江口与邻近西海岸沉积记录的耦合

通过对采自鸭绿江口主汊道的5个柱状样的210Pb和137Cs测年以及粒度参数的分析,并与前期合作研究的西汊道及西岸潮滩的4个柱状样沉积物的测年和粒度研究成果进行比对,探讨了流域来水来沙、河口沉积与海岸发育之间的耦合效应及鸭绿江河口地貌演化的新证据。结果表明:鸭绿江口主汊道存在河流和潮流两种沉积作用,不同时期动力作用不同;以潮流作用为主的沉积时段,其沉积特征与西汊道及西岸潮滩的一致;主汊道沉积物的物质来源与西汊道和西岸潮滩的物质来源存在差异。鸭绿江口的主汊道、西汊道及邻近海岸的沉积记录对环境变化、人类活动、流域大洪水等事件均存在响应,响应的时间基本同步,具有耦合效应。沉积记录中存在5个明显的“事件信号”,其中1960年最为重要,是鸭绿江河口地貌发生巨变的时间。     

基于耳石微结构的西北太平洋秋刀鱼(Cololabis saira)年龄与生长研究

根据2014年6月和10-11月在西北太平洋公海采集的168尾秋刀鱼样本,基于耳石微结构并结合基础生物学数据,鉴定了秋刀鱼的日龄,推算了孵化日期,并建立了生长模型和生长率。研究发现:耳石微结构从核心到透明区边缘,轮纹宽度由宽至窄,亮度由暗至明,标记轮多分布在透明区。日龄范围为204~549 d,优势日龄组为231~290 d和381~470 d,日龄最小个体体长207 mm,体质量39 g,日龄最大个体体长291 mm,体质量131 g。孵化日期为2012年12月至2014年4月,孵化高峰期出现在1-3月和8-10月,初步推算秋刀鱼主要分为春生群和秋生群产卵群体。体长和体质量生长模型符合Logistic生长模型。体长平均绝对生长率和相对生长率别为0.224 mm/d和0.000 88,绝对生长率随着日龄增加而减小。体质量平均绝对生长率和相对生长率别为0.293 g/d和0.003 25,最大绝对生长率（0.504 mm/d）和最大相对生长率（0.004 86）出现在351~400 d。     

Laboratory study on cement admixed marine silt bricks

For the purpose of efficient utilization of sediments dredged from harbor, a new method was proposed in this study. Marine silt bricks were made by mixing sediments with cement and gypsum, placing it in a cubic mold with 240 mm in length, 115 mm in width, and 53 mm in height, and curing for certain days. To investigate the effects of cement and initial water content of soil on the mechanical behavior of marine silt bricks, unconfined compressive and flexural strength tests were carried out. Given the same curing time and cement content, the higher the initial water content, the lower the compressive and flexural strength. After 60 days of curing, the compressive strength of marine silt bricks with cement content = 20% and water content = LL (liquid limit) reached approximately 5 MPa. The flexural strength was relatively low. The flexural strength of marine silt bricks with 20% cement and water content = LL was around 1.5 MPa. The compressive and flexural strength decreased with the increase of water/cement ratio. As for the curing time, longer curing time had a positive impact on the compressive strength. The ratio of flexural to compressive strength varied slightly in the range of 0.4–0.5.     

Prediction of one-dimensional compression behavior of Nansha clay using fractional derivatives

Nansha clay is an interactive marine and terrestrial deposited soft clay that is widely spread in Guangzhou, Pearl River Delta, China. To avoid excessive settlement after construction, there is a need for better quantifying the time-dependent deformation of the soft clay. This paper presents a preliminary study to predict the one-dimensional compression of Nansha clay using fractional derivatives. A fractional Merchant model was introduced to describe the time-dependent settlement, and analytical solutions were obtained in terms of the Mittag-Leffler function. The oedometer test results were presented to validate this model. Compared with classical rheological models, the fractional derivative-based model enabled close estimation of the one-dimensional compression with fewer parameters. The meaning of the order of fractional derivative and its relationship with the clay physical properties were explored. It shows that a smaller value of this order corresponded to a higher coefficient of consolidation and a lower coefficient of secondary consolidation. The amplitude of both the primary and secondary consolidation of clay may be estimated quantitatively by the order of fractional derivative. Taken together, these results may open up new avenues for theoretical and empirical modeling of rheological phenomena in clay using fractional derivatives.     

Model tests on installation and extraction of suction caissons in dense sand

A series of model tests were performed on steel- and Perspex-made suction caissons in saturated dense marine sand to explore installation and extraction behaviors. The extractions of the caisson were conducted by applying monotonic loading or by pumping water into the caisson. Responses of suction caissons to pullout rates, aspect ratios, and extraction manners were examined. Test results show that a cone-shaped subsidence region occurs around the suction caisson during the suction-assisted installation. The pullout bearing capacity of the suction caisson in sand is dominated by the loading rate and the loading manner. For the suction caisson subjected to monotonic loading, the maximum bearing capacity is reached at the pullout rate of about 20.0?mm/s. The mobilized vertical displacement corresponding to the pullout capacity increases with increasing the pullout rate. The passive suction beneath the suction caisson lid reaches the maximum value when the pullout bearing capacity is mobilized. In addition, during the suction caisson extracted by pumping water into the caisson, the maximum pore water pressure in the caisson is obtained under the displacement of approximately 0.04 times the caisson diameter. The absolute values of the maximum pore water pressures for the suction caissons approximately equal those of the maximum vertical resistances at the monotonic pullout rate of 5 mm/s. When the vertical displacements of the suction caissons with the aspect ratio of 1.0 and 2.0 reach 0.92 and 1.77 times the caisson diameter, respectively, the seepage failure occurs around the caissons. Using a scaling method, the test results can be used to predict the time length required for the prototype suction caisson to be extracted from the seabed.     

Characteristics and cause analysis of heavy haze in Changchun City in Northeast China

Northeast China has been reported as having serious air pollution in China with increasing occurrences of severe haze episodes. Changchun City, as the center of Northeast China, has longstanding industry and is an important agricultural base. Additionally, Changchun City has a long winter requiring heating of buildings emitting pollution into the air. These factors contribute to the complexity of haze pollution in this area. In order to analyze the causes of heavy haze, surface air quality has been monitored from 2013 to 2015. By using satellite and meteorological data, atmospheric pollution status, spatio-temporal variations and formation have been analyzed. Results indicated that the air quality in 88.9% of days exceeding air quality index(AQI) level-1 standard(AQI 50) according to the National Ambient Air Quality Standard(NAAQS) of China. Conversely, 33.7% of the days showed a higher level with AQI 100. Extreme haze events(AQI 300) occurred frequently during agricultural harvesting period(from October 10 to November 10), intensive winter heating period(from Late-December to February) and period of spring windblown dust(April and May). Most daily concentrations of gaseous pollutants, i.e., NO_2(43.8 μg/m~3), CO(0.9 mg/m~3), SO_2(37.9 μg/m~3), and O_3(74.9 μg/m~3) were evaluated within level-1 concentration limits of NAAQS standards. However, particulate matter(PM_(2.5) and PM10) concentrations(67.3 μg/m~3 and 115.2 μg/m~3, respectively) were significantly higher than their level-1 limits. Severe haze in spring was caused by offsite transported dust and windblown surface soil. Heavy haze periods during fall and winter were mainly formed by intensive emissions of atmospheric pollutants and steady weather conditions(i.e., low wind speed and inversion layer). The overlay emissions of widespread straw burning and coal combustion for heating were the dominant factors contributing to haze in autumn, while intensive coal burning during the coldest time was the primary component of total emissions. In addition, general emissions including automobile exhaust, road and construction dust, residential and industrial activities, have significantly increased in recent years, making heavy haze a more frequent occurrence. Therefore, both improved technological strategies and optimized pollution management on a regional scale are necessary to minimize emissions in specified seasons in Changchun City, as well as comprehensive control measures in Northeast China.     

黄河沙漠宽谷段水沙变化特征及驱动因素

根据定位观测、第一次全国水利普查、遥感影像解译的数据,利用MWP、双累计曲线、水土保持分析法、数学模拟等方法,分析了黄河上游水沙变化特征,评估了多元驱动因素对2000-2012年黄河下河沿-头道拐沙漠宽谷段水沙变化的贡献率。结果表明:与20世纪70年代以前的基准期相比,2000年以来径流量、输沙量同步减少,水沙关系也发生变化,单位径流量的输沙量明显减少;沙漠宽谷段径流量减幅沿程不断增加而输沙量减幅沿程变化不大,水沙年内分配较基准期发生倒置,来沙系数不断减小;灌区引水引沙、水土保持措施、水库拦沙、支流来水来沙、水库调蓄及河道冲淤是沙漠宽谷段水沙变化的主要影响因子;经济社会发展用水对沙漠宽谷段径流量减少的作用最大,贡献率为81%,其次是水库蓄泄量,占15%以上;水库拦沙对头道拐输沙量减少的贡献率最大,占41%,其次是支流水土保持措施,贡献率约占13%,入黄风沙减少的贡献率并不大,约为6%,而河道淤积量、灌区引沙量较基准期都是减少的,贡献率分别约为-41%和-8%;近10多年来降雨等自然因素对水沙变化的作用相对不大,起主要作用的是水库运用、水土保持、经济社会发展等人类活动因素。