Distribution of Carbon and Oxygen Isotopes in theSequence Stratigraphic Framework of the Middle andUpper Proterozoic in the Ming Tombs Area, Beijing

This paper discusses the distribution pattern and geological significance of the carbon and oxygen isotopes (δ13C and δ18O) in the depositional sequences of Gaoyuzhuangian, Yangzhuangian and Wumishanian ages of the established Middle and Upper Proterozoic sequence stratigraphic framework in the Ming Tombs area lying in western Yanshan Mountain of Beijing. Besides, sketchy determination of δ13C and δ18O was also performed for other formations and members. The analytical results show the following: under the condition of clear-water carbonate sediments, δ13C and δ18O, featuring smaller variation of δ13C but larger variation of δ18O, can well delineate the relative change of sea level, which reflects the difference of primary sedimentary settings; in the presence of terrigenous substances, δ13C values vary greatly while δ18O slightly; the carbon and oxygen isotopes show marked changes at sequence boundaries. Besides, particular patterns can be found in regard to the distribution of carbon and oxy     

濮城油田沙三中6-10油藏活性纳米粉体降压增注技术研究

濮城油田沙三中6-10油藏为低渗油藏,因注入水质差,造成对地层的伤害,注水压力不断上升。通过分析造成地层伤害的主要因素,为控制注水压力的上升,提出了活性纳米降压增注技术,并在室内进行了研究,从活性材料选择、表面修饰剂选择、分散介质选择以及纳米粉体水分散最佳浓度进行了室内筛选,指出了纳米酸化技术的可行性。在室内研究的基础上,在现场开展了10口井活性纳米技术的应用,取得了良好的效果。     

Morphology and distribution of the marine diatom Azpeitia africana (Janisch ex A. Schmidt) G. Fryxell & T. P. Watkins in the South China Sea

The purpose of the present paper is to study the morphological structure and variability of Azpeitia africana and to determine its geographical distribution in the surface sediments of the South China Sea(SCS). Sediment samples were collected with grabs or box corers in one cruise in 2001 and two cruises in 2007. The sampling stations were located between 3°56.61′–20°59.37′N and 108°30.68′–116°46.70′E,where the water depth ranged from 72 m to 4 238 m. The diatom was observed by phase contrast microscopy and scanning electron microscopy. Microscopical observation showed that A. africana had circular valves with the areolar lines radiating from the eccentric ring. The central rimoportula had an external tube recessed on the edge of a central ring. The marginal rimoportulae were not evenly spaced, and they were positioned more closely together in one quadrant than in the others. Azpeitia africana is the most abundant diatom species in the southern region of the SCS, and accounted for 0.9%–5.6% of all diatom species in the Xisha Islands area. Average cell density of A. africana was 1.1×10~5 valves/g. The percentage abundance of A.africana was low(0%–2.5%) in the northern regions of the SCS and the Sunda Shelf, and it was not detected in the northwestern continental shelf(shallow water area) and northern Kalimantan Island shelf. Our results suggested that A. africana is a typical warm water species and that it could be used as an indicator of the warm Paci?c Ocean water, including the Kuroshio Current, ?owing into the SCS.     

Numerical Modelling of Geochemical Behaviour of Fluoride in the Shallow Groundwater Systems

The Xingtai piedmont plain in Hebei Province is a representative area in northern China where endemic fluorosis is serious and shallow high-F ground water is distributed. In this paper, the area is selected as a typical study area, and on the basis of large amounts of field work and the experiments, through groundwater geochemical modelling and by applying the theory and method of the coupled model of hydrodynamic transport and chemical reactions in a multicomponent system, the author performed numerical modelling of the geochemical behaviour of fluoride in a shallow groundwater system, quantitatively studied the hydrodynamic transport and chemical reaction of fluorine migration, transformation and concentration in a water-heterogeneous unsaturated soil system under the conditions of meteoric water infiltration and quantitatively determined the speciation of fluorine and the saturation state and dissolution/precipitation trend of various solid precipitates in shallow high-F groundwater, thus deepening t     

漳州地下热水开采与地面沉降预测

据福建省漳州市漳州地热详查报告(1988年),漳州市城区地热田孔隙热水水位降深1.16 m~5.0 m(平均4.41 m),允许开采热水资源5 410.08 m3/d,但目前的开采量为883.20 m3/d,仅占16%,若全部开采,势必引起地面沉降。根据漳州地热田水位降深段内土体浮力消失,相应自重应力增加而引起压缩变形原理,预测漳州地热田平均水位降深4.41 m引起的地面沉降值,Ⅰ级阶地为3.85 cm~8.66 cm,按有关地热田沉降资料研究,沉降差超过2.0cm时,地下水泥管道将会破裂。因此,漳州孔隙热水资源全部开采可能引起地面沉降,导致局部建筑物开裂,影响安全使用。     

Mesozoic radiolarian chert from the middle sector of the Yarlung Zangbo suture zone,Tibet and its tectonic implications

The middle sector of the Yarlung Zangbo suture zone stretches over 200 km long from Ngamring through Geding to Rinbung, roughly along Yarlung Zangbo River valley (Fig. 1). This belt resulted from the closure of the Tethyan ocean and the collision be- tween Indian plate and Lhasa block[1―8]. Lots of works demonstrated that rifting of the Tethyan basin in southern Tibet started from Triassic time. Initial oce- anic crust appeared in the Late Jurassic, and then ex- perienced a rapid sprea…     

碳酸盐岩有机质赋存形式及成烃特征

在分析多种有机质赋存形式的基础上，探讨了塔里木盆地下古生界和南华北石炭系碳酸盐岩的各种有机质含量关系及其成烃演化特征。研究发现，一般操作条件下所得的沥青Ａ和尖青Ｃ并非真正意义的吸附有机质和包裹有机质。目前还无法将真正的包裹有机质从碳酸盐岩中分离出来，由于成熟度，排烃条件等的影响、碳酸盐岩中各种有机质含量的相关关系不明显，仅沥青Ａ和沥青Ｃ有比较差的正相关关系。     

阿坝牧区冻灾天气成因分析和预报

分析了阿坝州牧区冻灾天气的形成过程和形成物理机制,得到冻灾天气主要由辐射、平流和融雪三要素降温而形成,在个例分析的基础上,建立了冻灾天气预报模式.     

职住分离的度量方法与空间组织特征——以北京市轨道交通对职住分离的影响为例

基于问卷调查获取的万份调查数据,构建了以通勤时间/距离为基础数据的职住分离度量模型,即基于频数分布法的通勤时间/距离和基于不同时段/区段范围内居民分布结构的"职住分离强度指数".根据上述判别模型与计算结果,发现:①各样本区居民通勤时间普遍增加,城市外围区轨道交通沿线居民通勤时间多数集中在40分钟以上,自购居民的通勤时间...     

偏振遥感的中性点大气纠正方法研究

地表物体具有较强的偏振特性,因此可以作为偏振遥感的信息源。但是,大气的偏振效应强于地表的偏振效应,导致星载遥感器无法有效接收地表目标的偏振信息,大气的起振与退偏效应成为偏振遥感对地表目标进行观测和应用的一个瓶颈问题。本文提出一种利用大气中性点对偏振遥感中地表偏振效应与大气偏振效应进行分离的方法,通过天空中大气线偏振度为零的中性点区域进行对地观测,目的是去除大气偏振作用,进而最大限度地获取地表目标偏振信息。地面实验的结果验证了利用大气中性点进行大气纠正具有理论上的可行性。