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新疆北部上石炭统发育于碰撞后松弛垮塌构造环境,火山岩和烃源岩间互广泛分布,石炭纪末受板块挤压整体抬升遭受风化淋滤,使火山岩不整合风化体形成5层结构,其中溶蚀带和崩解带是有利储层发育段,火山岩风化体发育于古地貌出露水面区,低洼处和斜坡带发育较完整的5层结构,高部位一般缺失土壤层.风化体厚度与风化淋滤时间呈正向非线性指数关系,风化体厚度动态平衡时间约为36.3Ma,最大风化体厚度约450m,断裂发育处风化体厚度更大,长期风化淋滤区各种火山岩岩性均能形成风化体.火山岩风化体和烃源岩组合,发育源内火山岩风化体层序型、源上火山锥风化体准层状和侧源火山岩风化体梳状3种成藏模式,均可形成大型火山岩风化体地层油气藏.该认识改变了火山岩油气勘探中寻找有利岩性和岩相带的传统模式,修正了新疆北部石炭系为盆地基底,不具备油气生成条件的观点,对指导火山岩风化体油气勘探具有重要的科学意义和应用价值.指出中国中西部古生界存在形成大规模火山岩风化体地层油气藏的条件,是今后油气勘探的新领域.  相似文献   
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To explore the spatial heterogeneity of plankton communities in a deep artificial lake(Songhua Lake,China),samples were collected at seven sites. Samples were investigated by denaturing gradient gel electrophoresis(DGGE) analysis of the PCR-amplified 16 S and 18 S r RNA genes and specif ic bands were sequenced. Cluster analysis of the DGGE profiles revealed that all of the samples grouped into two distinct clusters,in accordance with sampling site; while in each cluster,the divergence of sub-clusters correlated with sampling depth. Sequence analysis of selected dominant DGGE bands revealed that most sequenced phylotypes(84%) exhibited ≥97% similarity to the closest sequences in Gen Bank,and were affiliated with ten common freshwater plankton phyla(Proteobacteria,Actinobacteria,Bacteroidetes,Cyanobacteria,Bacillariophyta,Pyrrophyta,Cryptophyta,Ciliophora,Stramenopiles,and R otifera). Several of these groups are also found worldwide,indicating the cosmopolitan distribution of the phylotypes. The relationships between DGGE patterns and environmental factors were analyzed by redundancy analysis(RDA). The results suggested that,total nitrogen,nitrate,nitrite,ammonia,and CODM n concentrations,and water temperature were strongly correlated with the variation in plankton composition.  相似文献   
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