稳定碳同位素δ13C1在煤层气田勘探中的应用

煤层气分布状态主要受控于两种地质效应：一种是热动力学机制控制下的同位素分馏效应，存在于煤层气生成期；另一种是甲烷δ^13C1解吸一扩散一运移效应，存在于煤层气生成后，源于埋深变浅而造成的泄压条件下。文中以沁水煤层气田为例，探讨了沁水煤层气田煤层气δ^13C1解吸-扩散-运移效应。认为可以利用煤层气δ^13C1特征来评价煤层气保存条件和开采稳定性，指导煤层气田的勘探和开发。     

Climate as the dominant control on C3 and C4 plant abundance in the Loess Plateau： Organic carbon isotope evidence from the last glacial-interglacial loess-soil sequences

Abundance of C3 and C4 photosynthesis plants can be inferred relatively from stable carbon isotopic composition of organic matter in soils. The samples from five sequences of the last glacial-interglacial loess-soil in the Chinese Loess Plateau have been measured for organic carbon isotopic ratios (613Corg). The organic carbon isotope data show that relative abundance (or biomass) of C4 plants was increased ca. 40% for each sampling site from the last glacial maximum (LGM) to Holocene optimum, and increased southeastward on the Loess Plateau during both periods of LGM and Holocene. Statistic analyses on the steady maximum δ^13Corg values of Holocene soils and modern climatic data from the Loess Plateau and Inner Mongolia indicate that the C4 plant abundance increases with increasing temperature and decreasing precipitation. The C4 plant abundance is related much closer with mean April temperature and precipitation than annual. These results lead us to deduce following conclusions. First, temperature is the major factor for control on variations in C4 plant abundance in the Loess Plateau from the last glacial to interglacial. In the absence of favorable temperature condition, both of low moisture and low atmospheric CO2 concentration are insufficient to drive an expansion of the C4 plants in the plateau. Second,δ^13Corg in the loess-paleosol sequences, as a proxy of the relative abundance of C4 plants in the Loess Plateau, could not be used as an indicator of changes in the summer monsoon intensity unless the temperature had changed without great amplitude. Since all C4 plants are grasses, finally, the increase of the C4 plants supports that forest has not been dominant in the ecosystem on the Loess Plateau during Holocene although precipitation and atmospheric CO2 were largely increased relative to those during LGM.     

Response of the northwestern Pacific upper water δ~(13)C to the last deglacial ventilation of the deep Southern Ocean

The deglacial δ~13C minimum events that originated from the ventilation of the deep Southern Ocean around Antarctica, have been recorded in a range of marine sediments from the southern to tropical oceans in late Pleistocene. However, the broad δ~13C minimum event was also reported as far as to the northern middle latitudes, in northwestern Pacific marginal sea areas, during the last deglaciation. In the northwestern Pacific, forcing from the northern high latitudes is strongly expressed, while the records of in- fluence from the southern high latitudes are few. The Kuroshio Source Region (KSR) forms a boundary between the northwestern Pacific and the southern, tropical Pacific. So, high-resolution planktonic foraminiferal records in core MD06-3054 from the KSR are well positioned to identify signals from the southern hemisphere in the northwestern Pacific. Planktonic foraminiferal tests from the upper 1030 cm of the core were subject to AMS14C, carbon and oxygen isotopic measurements. A negative excursion was found to occur from about 20.0-6.0 ka BP in δ~13C records of both surface (Globigerinoides ruber) and subsurface (Pulleni- atina obliquiloculata) dwellers, but the overall trends of the two curves have reversed since 26.5 ka BP. Moreover, the δ~13C rec- ord of G. ruber (the surface dweller) shows a robust link to the record of atmospheric CO2, and its changes precede the records of P. obliquiloculata (the subsurface dweller). According to the hydrologic conditions, the broad δ~13C minimum event recorded in the KSR is also a response to the increasing ventilation of the deep Southern Ocean around Antarctica during the last deglaciation. The inconsistency between the records of the surface and subsurface dwellers was possibly caused by the ways that the low δ~13C signal was transmitted. Subsurface water primarily received the low δ~13C signal from the Antarctic Intermediate Water (AAIW), whereas the surface water was probably mainly impacted by atmospheric CO2 in the KSR. The records from the KSR confirm the deduction that the broad δ~13C minimum event in the Okinawa Trough was due to the impact of tropical Pacific surface water dur- ing the last deglaciation, and suggest that signals from the southern high latitudes also can be delivered to the northern middle latitudes.     

Foliar δ^13C and δ^15N values of C3 plants in the Ethiopia Rift Valley and their environmental controls

The foliar C and N stable isotopic compositions （δ^13C and δ^15N） and the relationships between these compositions and environmental factors of C3 plants in the Ethiopia Rift Valley were investigated. There were three distribution patterns for foliar δ^13C with mean values of -26.7‰±0.4‰, -29.7‰ ±0.6‰ , and -26.9‰± 1.2‰ in cold-moist, temperate-moist, and arid-hot environments, respectively. The δ^15N values ranged from -1.4‰ ±1.7‰ to 14.3‰ ± 0.1‰, with higher values under arid-hot conditions and the lowest values in plants growing at higher altitudes under cold-moist conditions. A strong negative relationship between mean annual precipitation and δ^15N explained more than half of the observed variation in the δ^15N values （r2= 0.54, P 〈 0.001）; a modest positive relationship was also found between δ^15N and temperature （r2 = 0.32, P 〈 0.01）. A weakly positive relationship existed between δ^13C and temperature, and changes in δ^13C values with precipitation and altitude followed quadratic curves. This suggests a shift in the effects of water and heat conditions caused by altitude on carbon isotopic discrimination.     

Effect of land use on microbial biomass－C, －N and －P in red soils

Eleven red soils varying in land use and fertility status were used to examine the effect of land useon microbial biomass -C, -N and -P. Microbial biomass-C in the red soils ranged from about 68 rag C/kg to 225 mg C/kg, which is generally lower than that reported from other types of soil, probably because of low or-ganic matter and high acidity in the red soils. Land use had considerable effects on the amounts of soil Cmic.The Cmic was the lowest in eroded fallow land, followed by woodland, tea garden, citrus grove and fallow grassland, and the highest in vegetable and paddy fields. There was significant correlation between Cmic and organic matter content, suggesting that the influence of land use on Cmie is mainly related to the input and ac-cumulation of organic matter. Microbial biomass-N in the soils ranged from 12.1 Nmg/kg to 31.7 Nmg/kg andwas also affected by land use. The change of Nmic with land use was similar to that of Cmic. The microbial C/N ratio ranged from 5.2 to 9.9 and averaged 7.6. The Nmic was significantly correlated with soil total N and available N. Microbial biomass-P in the soils ranged from 4.5 mg P/kg to 52.3 rag P/kg. The microbial C/P ratio was in the range of 4-23. The Pmic was relatively less affected by land use due to differences in fertili-zation practices for various land use systems.     

δ~(13)C difference between plants and soil organic matter along the eastern slope of Mount Gongga

Carbon isotope ratios (δ 13C) of plants, litter and soil organic matter (0–5 cm, 5–10 cm and 10–20 cm) on the eastern slope of Mount Gongga were measured. The results show that δ 13C values of plants, litter and soil organic matter all decrease first and then increase with altitude, i.e. δ 13C values gradually decrease from 1200 to 2100 m a.s.l., and increase from 2100 to 4500 m a.s.l. The δ 13C altitudinal variations are related to the distribution of C3 and C4 plants on the eastern slope of Mount Gongga, ...     

δ^13C and water-use efficiency indicated by δ^13C of different plant functional groups on Changbai Mountains,Northeast China

Leaf δ^13C of different plant functional groups （trees, shrubs and forbs; evergreen and deciduous; annual, biennial and perennial） were examined on the Changbai Mountains, China. Life form has a significant influence on plant δ^13C, suggesting that leaf δ^13C is also ideal for distinguishing functional groups species in temperate and frigid zones with high humidity. Additionally, the difference of water-use efficiency （WUE） is significant among different plant functional groups. δ^13C and WUE are in the following order of forbs 〈 shrubs 〈 trees. Within shrubs, δ^13C and WUE are higher for evergreen shrubs than deciduous shrubs. Differences in δ^13C and WUE are significant among different lifespan herbs, and δ^13C and WUE follow the order of annual herbs 〉 biennial herbs 〉 perennial herbs, not in accordance with the pattern obtained by previous studies in deserts, suggesting that the ranking of δ^13C and WUE among annual, biennial and perennial herbs may be dependent on local water availability.     

扬子板块东南大陆边缘上震旦统热水成因硅质岩的地球化学标志

晚震旦世时,在扬子板块东南大陆边缘地带发育一套层状硅质岩建造,岩石化学成分纯净,SiO2含量在90%以上,其它化学成分含量均很低。但Fe和Mn相对富集,而Al,Ti,Mg相对贫乏。微量元素含量变化大,大部分微量元素含量相对地壳克拉克值偏低,仅U,As,Sb,Ag,Ba等富集。岩石的δ30Si为0.0‰～0.7‰,δ18O为20.2‰～23.6‰,δ30Si和δ18O值及岩石的形成温度清楚地表明组成岩石的二氧化硅矿物来源于热水     

广西融水蛇绿岩及其矿床组合特征

本文通过对广西融水一带蛇绿岩野外地质、常量元素岩石化学、微量元素及稀土元素地球化学研究,论证了该蛇绿岩及其形成的构造环境,并对蛇绿岩套中的矿床组合特征及成矿作用作了论述。     

中扬子区上震旦统层序地层研究

以中扬子区上震旦统为对象,研究了层序界面和体系域特点,分析了层序样式的基本类型及其特征,共划分出2个二级层序,8个三级层序.陡山沱组划分了1个二级层序(SS1),四个三级层序(ZSQ1～ZSQ4),平均延时12.5 Ma;体系域颜色普遍较深,泥质含量较高,是一套良好的烃源岩;T型样式和H型样式为主,并且T型样式较多,反映陡山沱期水体较浅.灯影组划分出1个二级层序(SS2),四个三级层序(ZSQ5～ZSQ8),平均延时约20Ma;体系域颜色普遍较浅,云质含量较高,是一套良好的储集层;T型样式和H型样式为主,并且H型样式较多,反映灯影期水体也较浅.二级层序体系域和三级层序体系域都表现出明显的南北向差异性.     

皖西震旦纪冰成岩岩石学研究

本文系地矿部项目《苏皖北部上前寒武系研究》的部分成果并进一步深化而成,对著名的皖西凤台组砾岩进行了系统的岩石学研究,通过多方法,多因素综合研究,得出“凤台组属冰成岩”的结论,但又有它自身的特殊性,文中对此作了深入的论证并提出若干新的见解。     

光-象平面自动标定方法的研究——用于三维计算机视觉系统

分析了三维视觉系统空间标定的困难以及利用光平面反映空间点坐标的方便之处。建立了光—象平面自动标定方法,经过标定实验数据分析,得到了笔者所使用系统的最大测量误差为1.2％,并分析了误差的可能性及必然性。     

以车牌识别技术为核心的高等级公路收费系统

以嵌入式车牌识别技术为核心，提出了一个全新的高等级公路收费系统方案，解决了长期困扰高等级公路经营者和管理者不能准确控制收费的问题。     

A new discovery of macroscopic fossils from the Ediacaran Doushantuo Formation in the Yangtze Gorges area

The Ediacaran section in the Yangtze Gorges area, South China, is one of the most important in the worldand contains abundant fossils[1-4]. The earliest discov- ery of macrofossils in 1984, including macroscopic algal fossils from the uppermost Doushantuo…     

菲涅耳波带片的焦距

菲涅耳波带片是一种光学器件，它具有易制造、面积大、轻便、可折迭等特点，已广泛应用于远程光通讯、测距、宇航技术中。本文主要讨论菲涅耳波带片的焦点和焦距。     

塔里木盆地西南缘的构造演化与岩石组合

塔里木盆地西南缘可划分为３ 个地层区和２ 个缝合带。该区自震旦纪来经历了两大构造旋回,发育３ 种类型的岩石组合。库地缝合带是库地洋经历了一次开合的遗迹,分离了西昆仑与塔里木这两个地层区。康西瓦缝合带是康西瓦洋经历了两次开合的遗迹,它分别是塔里木与羌塘两板块和西昆仑与喀喇昆仑两地层区的分界线。