Origin and occurrence of 25-norhopanes: a statistical study   总被引：1，自引：0，他引：1  

Ph. Blanc  J. Connan 《Organic Geochemistry》1992,18(6)

The alkane fraction of more than 200 rocks, biodegraded oils and non-biodegraded oils, have been analysed by means of computerized GC-MS, in order to investigate the effect of natural biodegradation on the occurrence of “demethylated hopanes”, i.e. 17α-25-norhopanes. The results obtained indicate that 25-norhopanes are preexisting biomarkers the concentration of which is enhanced by selective biodegradation of more readily degradable homologs, i.e. regular hopanes, rather than by demethylation of hopanes in reservoirs. However, the use of 25-norhopane enrichment as a palaebiodegradation indicator in apparently non-biodegraded oils is still valuable providing the initial background content in the corresponding source rocks is known. Furthermore, 25-norhopanes appear to be diagnostic of specific environmental conditions (marine and lacustrine source rocks, dysoxic and not very hypersaline). Lastly, one other (novel) bacterially resistant rearranged hopanoic compound, namely a C₂₉ neohopane, is applicable for both biodegradation and maturation evaluation.  相似文献   

基性、超基性岩及矿产研究概述 庆祝地矿部西安地质矿产研究所建所30周年     

李行 《西北地质科学》1992,(2)

主要介绍我所30年来,在基性、超基性岩及有关矿产研究方面的基本概况、取得的进展及今后一些展望。其中所列进展主要包括:岩浆矿床学、岩石及成因学、岩浆建造学及矿床评价和预测等四个方面的研究。  相似文献   

Mechanical behaviour of deep rock core samples from a seismically active gas field     

D. Fabre  J. -R. Grasso  Y. Orengo 《Pure and Applied Geophysics》1991,137(3):201-219

This study concerns the laboratory testing of core samples from massive sedimentary rocks from an oil and gas field. The depth of extraction of the samples analysed varies between 1000 and 5000 metres. In all, 65 tests were performed, most of which included systematic measurement of acoustic activity during loading. The aim of the testing was to determine which types of fracture could occur in the rock matrix under field-stress conditions by examining in particular the relationship between confining pressure and the transition from brittle to ductile behaviour. The results of the laboratory tests are used to predict the occurrence of seismic activity resulting from the depletion of the gas reservoir which has been monitored during the last twenty years.  相似文献   

海南岛第四纪玄武岩风化壳中次生矿物转变与时间的关系   总被引：2，自引：0，他引：2  

冯锦江  胡碧菇 《岩石学报》1991,7(3)

本文采用X射线分析法,从分析风化壳中的次生矿物入手,研究了海南岛北部不同地质年龄的第四纪玄武岩风化壳中次生矿物增长数量与风化时间的关系。两者关系的回归方程为Y=4.1898 207.30t,其中Y为次生矿物的含量(g/cm~2),t为风化时间(Ma)。相关系数γ=0.9977。每0.01Ma次生矿物平均增长2.2164g/cm~2。  相似文献   

耗散结构理论及其在火成岩岩石学中的意义   总被引：2，自引：0，他引：2  

张招崇  李兆鼐 《岩石矿物学杂志》1991,10(3):221-227

本文简要介绍了耗散结构理论及其研究方法,以及它在火成岩中的应用,其中包括以下几个方面:(1)基性杂岩体的层状构造;)2)花岗岩中的球状构造;(3)斜长石的环带;(4)花岗岩体的成分分带。并讨论了这四种耗散结构的形成机理。这些耗散结构都是在远离平衡的条件下,通过内部不可逆的非线性过程,由于外界的扰动和内部的涨落造成定态的失稳而形成的。其形成的根本原因是其内部反馈机制作用的结果。斜长石的环带是时间耗散结构——极限环。利用耗散结构理论简要地解释了辽宁二道沟花岗闪长岩的成因。  相似文献   

砂屑岩的综合结构系数与沉积环境分析   总被引：1，自引：2，他引：1  

宋天锐 《岩石矿物学杂志》1991,10(3):210-220

本文讨论了砂屑岩综合结构系数与沉积环境分析的实例。 这里介绍的测定砂屑岩结构成熟度的方法是在显微薄片粒度分析基础上提出的,其中包括了成熟度、分选性、颗粒圆度和岩石的杂基等多种因素。综合结构系数可按下式求得: T=(SoΦPo)/(PΦC) 因为圆度是在显微镜下的薄片中求得,因而总是比实际投影的易反映其棱角而降低了圆度,所以采用了[p02 (R-A)2]0-5来校正颗粒的圆度,于是得出了发展的综合结构系数Td:Td=SoΦ[P02 (R-A)2]0.5/(PΦC)多数情况下Td和T很接近,只是颗粒圆度非常好时才拉大差距,因此,Td可用来检验超成熟度的砂岩。 本文提出了四种成熟度阶段:不成熟的(T<10);次成熟的(T=10-40);成熟的(T=40-100);超成熟的(T或Td>100)。  相似文献   

钽钼酸—丁基罗丹明B—PVA体系光度法测定痕量钽   总被引：1，自引：0，他引：1  

罗宗铭  梁洁贞 《岩矿测试》1991,10(2):89-92

Ta(V)与钼酸盐在pH3.7形成钽钼酸,并在0.29mol/L的H_2SO_4介质中,与丁基罗丹明B(BRHB)形成离子缔合物,其组成比为Ta:Mo:BRHB=1:6:3。有聚乙烯醇(PVA)存在时,该缔合物能稳定存在于水溶液中。缔合物的最大吸收在588nm,ε_(588)=3.62×10~5L·mol~(-1)·cm~(-1),Ta在0—5μg/25ml范围符合比尔定律。方法应用于硅酸盐岩石中痕量Ta的测定,结果满意。  相似文献   

The experimental study of parameters of rocks under ultrahigh-pressure state     

Changtai Liu  Naiguang Geng 《地震学报(英文版)》1992,5(1):161-168

The parameters of rocks in ultrahigh-presure state are very important to understanding the geodynamics and explosion engineering of rocks. In these experiments the plane wave dynamite lenses were used to drive the flying plates. The flying plate hits the target and produces the ultrahigh-pressure shock wave. The propagation velocity and the particle velocity of shock wave in rock samples were measured by probes, and the relation between density of rocks and pressure was obtained by Rankine-Hugoniot formulas. The maximum pressure in experiments was higher than 70 GPa. The ultrahigh-pressure state formulas obtained are: Limestoneρ=3.22+0.016p; Graniteρ=3.20+0.024p. In which the unit for ρ is g/cm³, the unit forp is GPa. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 96–103, 1991.  相似文献   

有机岩石学及其在油气评价中的应用   总被引：1，自引：0，他引：1  

肖贤明 《地球科学进展》1992,7(2):39-44

  简要介绍了有机岩石学研究方法的发展与特.点，系统的论述了这门新兴学科用于确定烃源岩成熟度、有机质类型，研究油气生成、运移与聚集等方面所取得的进展。
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延边闹枝破碎蚀变岩型金矿床研究     

潘丽敏  邹祖荣 《吉林大学学报(地球科学版)》1992,(2)

延边地区闹枝金矿为一破碎蚀变岩型金矿床,产于中生代火山盆地外缘的早海西期花岗闪长岩出露区,矿体严格受构造破碎带控制。本文从矿床产出的地质地球化学特征入手对区内岩浆岩与成矿的关系进行了系统研究,揭示出闹枝金矿与中生代火山杂岩有密切的成因联系.闹枝金矿为—燕山期钙碱性火山岩浆活动所形成的火山—次火山热液矿床.矿床形成于中温、pH值为弱酸—弱碱性、Eh值较低的弱还原—还原条件.成矿作用具有多阶段性。金主要以氯金络合物和硫金络合物形式迁移.  相似文献