黑龙江伊春红山华夏—安加拉混生植物群

系统研究了黑龙江省伊春红山地区晚二叠世红山组植物群,认为其性质为华夏—安加拉混生植物群。华夏植物区与安加拉植物区的界限,应以内蒙古陆及其东、西延展部分为界。     

天然气藏He的累积模式及定年应用初探

天然气藏He的聚集存在一定的年代累积效应,借鉴相关地质模型,引入气藏特征参数,对外部壳源以及气藏原位产生的He进行量化,明确天然气藏中He累积量与时间的数学关系,进而建立了约束天然气藏形成时代的新方法——He定年模型。将该方法应用于四川盆地威远气田,估算威远震旦系天然气成藏定型的时间约为31Ma,对应渐新世,处于喜马拉雅运动中期。该结果与威远气田成藏过程的研究成果相吻合,表明天然气藏He的年代累积效应可以用于成藏时代的研究,所建立的He定年模型具有一定的实用性和应用潜力。     

利用扫描电镜-电子探针研究四川杨柳坪镍铜硫化物矿床铂钯的赋存状态及沉淀机制

本文利用电子探针和配备能谱分析功能的扫描电镜对四川杨柳坪镍-铜硫化物矿床中铂钯的赋存状态进行了研究。结果表明,铂以独立矿物相砷铂矿和自然铂存在;钯以碲化物、碲铋化物、碲锑化物、锑化物及自然钯独立矿物相存在,也以类质同象形式分布在碲镍矿中(钯含量约10%),另外还以锑铋钯碲矿、六方锑碲钯矿、碲钯矿独立矿物相存,并以类质同象形式分布在Vavrinite(钯含量5%)和砷铂矿(钯含量1%~5%)中。杨柳坪矿床中铂钯元素沉淀与贱金属矿物(BMS)及晚期热液蚀变矿物蛇纹石、方解石密切相关,其沉淀经历了3个阶段:1早期高温阶段(1200~900℃),铂钯元素沉淀并包裹在BMS中;2中期中高温阶段(650~250℃),分离结晶作用使铂钯元素沉淀并分布BMS矿物的边部,同时该阶段热液来源的铂钯元素沉淀于BMS粒间;3晚期热液蚀变阶段(500~300℃),热液蚀变作用引起铂钯元素沉淀在蚀变矿物中或嵌布在BMS裂隙。本文研究成果为认识该矿床及同类型镍-铜硫化物矿床的铂钯成矿过程提供了新的依据。     

基于最优加权组合的甘肃金川矿14行风井变形预测

金川14行风井直接关系到矿山的安全生产。本文建立了3种单一预测模型,并根据最优加权组合原理得到了最优加权组合预测模型。最优加权组合预测模型包含了单一模型的有效信息,提高了变形的预测精度。最优加权组合预测模型的模型精度与权重分配与单一模型的选取有关。作为一种短期预测模型,得出金川14行风井在近两个半年会保持稳态变形,不会出现大的突变。     

一种简单的辉钼矿Re-Os同位素年龄测定中Re化学分离方法：“钽试剂”萃取法

介绍了一种简单的辉钼矿Re-Os同位素定年中Re的化学分离方法,采用“钽试剂”（N-苯甲酰基苯基羟胺）的氯仿溶液萃取辉钼矿中的主要基体和干扰元素,如Mo、Fe和W,达到Re与这些主要基体元素分离的目的。在此基础上,建立了Carius管溶样-四氯化碳萃取分离Os-“钽试剂”萃取分离Re以及同位素稀释电感耦合等离子体质谱法测定的分析流程。利用该分析流程,对辉钼矿标准物质JDC进行Re-Os同位素年龄测定研究,测得其Re、Os的平均含量及年龄分别为（17．6±0．2）μg／g、（25．9±0．3）ng／g和（140．1±2．4）Ma,该结果在误差范围内与标准参考值一致。与目前常用的辉钼矿Re-Os同位素定年方法相比,该方法具有操作简便、快速、高效以及成本低的优势,非常适合作为辉钼矿Re-Os同位素定年的化学分离常规方法。     

Geochemical features and origin of natural gas in heavy oil area of the Western Slope,Songliao Basin,China

The Western Slope of the Songliao Basin is rich in heavy oil resources (>70 × 10⁸ bbl), around which there are shallow gas reservoirs (∼1.0 × 10¹² m³). The gas is dominated by methane with a dryness over 0.99, and the non-hydrocarbon component being overwelmingly nitrogen. Carbon isotope composition of methane and its homologs is depleted in ¹³C, with δ¹³C₁ values being in the range of −55‰ to −75‰, δ¹³C₂ being in the range of −40‰ to −53‰ and δ¹³C₃ being in the range of −30‰ to −42‰, respectively. These values differ significantly from those solution gases source in the Daqing oilfield. This study concludes that heavy oils along the Western Slope were derived from mature source rocks in the Qijia-Gulong Depression, that were biodegraded. The low reservoir temperature (30–50 °C) and low salinity of formation water with neutral to alkaline pH (NaHCO₃) appeared ideal for microbial activity and thus biodegradation. Natural gas along the Western Slope appears mainly to have originated from biodegradation and the formation of heavy oil. This origin is suggested by the heavy δ¹³C of CO₂ (−18.78‰ to 0.95‰) which suggests that the methane was produced via fermentation as the terminal decomposition stage of the oil.     

Climate impacts: temperature and electricity consumption

Natural Hazards - One of the aspects of climate change is temperature rise. Temperature rise or fluctuations affect human economic activities and electricity consumption. This paper estimates the...     

微波消解等离子体发射光谱和石墨炉原子吸收光谱法联合测定土壤中多元素

采用密闭式微波消解系统处理土壤样品,电感耦合等离子体发射光谱法或石墨炉原子吸收光谱法测定土壤样品中铜、砷、铅、锌、钴、铬、锰、镍、钒9个元素。分别从消解液的选择、用酸量及样品消解量等方面进行消解条件的优化,确定了一个最适合土壤消解的前处理体系。各元素的检出限为0.16～2.52μg/g,回收率为95.2%～106.6%,精密度为2.03%～9.79%(n=7)。方法简单快速,效率高,劳动强度低,是进行土壤中多元素测定的高效方法。     

Episodic crustal growth of North China as revealed by U-Pb age and Hf isotopes of detrital zircons from modern rivers

Clastic sedimentary rocks are samples of the exposed continental crust. In order to characterize the crustal growth history of North China and its possible regional variations, 479 concordant detrital zircons in three sand samples from the lower reach of the Yellow River (which drains the Tibet-Qinghai Plateau, the Western Qinling Orogen, the Qilian Orogen and the North China Craton) and two sand samples from the Luan River and the Yongding River (which run entirely within the North China Craton) were measured for U-Pb age and Lu-Hf isotopic compositions by excimer laser-ablation ICP-MS and MC-ICP-MS. Although regional variations exist, concordant detrital zircons from the Yellow River reveal three major age groups of 2.1-2.5 Ga, 1.6-2.0 Ga, and 150-500 Ma. Detrital zircons from the smaller Luan and Yongding Rivers show three broadly similar major age groups at 2.3-2.6 Ga, 1.6-2.0 Ga, and 140-350 Ma, but with narrower age ranges. Compared to the Luan and Yongding River zircons, the Yellow River zircons are characterized by a significant number of Neoproterozoic grains. Although Hf isotopic compositions show both juvenile crustal growth and crustal reworking for all age groups, much of the crustal growth of North China occurred in the Neoarchean and Mesoproterozoic. All three rivers are characterized by a common prominent group of Hf crust formation model ages at 2.4-2.9 Ga with a peak at 2.7-2.8 Ga. A less significant age group lies between 1.4 and 1.8 Ga for the Yellow River, and between 1.6 and 1.9 Ga for the Yongding River and Luan River. Crustal growth rates based on Hf continental crust formation model ages suggest 45% and 90% of the present crustal volume was formed by 2.5 Ga and 1.0 Ga, respectively, for the drainage area of the Yellow River. In comparison, 60% and 98% of the present crustal volume of the North China Craton was generated by 2.5 Ga and 1.0 Ga, respectively, for the Luan and Yongding Rivers. The 2.7-2.8 Ga age peak observed in all river samples agrees well with the coeval major peak for global crustal growth. However, the other suggested global peaks of crustal growth at 3.4 and 3.8 Ga are insignificant in North China. Taken together with our previous studies of the Yangtze Craton, which show insignificant crustal growth at 2.7-2.8 Ga, we suggest that these advocated worldwide crust formation peaks be re-examined and treated carefully. Our results also show that Phanerozoic zircons may have been derived from crustal sources separated from the mantle up to 2.0 Ga ago before the zircons crystallized, suggesting long-term preservation, reworking and recycling of the continental crust.