Characteristics,differences and main controlling factors of source rocks in the central‐southern South China Sea Basins

The South China Sea is rich in oil and gas resources. With the increasing exploration of oil and gas resources in the northern South China Sea and the increasing demand for energy in the world, The central‐southern South China Sea have become important constituencies for oil and gas resources. The central‐southern basins of South China Sea can be divided into three types of basin groups, namely, the southern basin group (Zengmu Basin, Brunei‐Sabah Basin), the western basin group (Wan'an Basin, Zhong jiannan Basin) and the Central Basin Group (Liyue Basin, Beikang Basin, Nanweixi Basin and Palawan Basin). At present, the degree of exploration is relatively low, and the source rock has not yet formed a understanding of the system. The main source rock development time, source rock characteristics, hydrocarbon generation potential and control factors of each basin group are still unclear, which seriously restricts the exploration of oil and gas. Based on the sedimentary facies distribution and sedimentary filling evolution, combined with the geoche mical characteristics of the source rocks, the source age, organic matter type, hydrocarbon generation potential and main controlling factors of the basins in the central‐southern basins are discussed. By the detailed research on delta scale, provenance system, paleoclimate conditions, ancient vegetation development and hydroca rbon generation parent material, the main controlling factors of hydrocarbon generation potential of source rocks in each basin group are revealed.     

Can PAHs influence Cu accumulation by salt marsh plants?

The presence of polycyclic aromatic hydrocarbons (PAHs) may change the mechanisms of metal uptake, thus influencing kinetics and extent of metal phytoextraction. Studies on the subject are scarce, particularly for salt marsh plants. The aim of this work was to investigate the effect of PAHs on the uptake of Cu by Halimione portulacoides, a plant commonly found in salt marshes. Experiments were carried out in the laboratory, either in hydroponics (sediment elutriate) or in sediment soaked in elutriate, which were prepared with sediment and water from a salt marsh of the Cavado river estuary (NW Portugal). Groups of H. portulacoides (grown in a greenhouse) were exposed to those media during six days. Cu(2+) (as Cu(NO(3))(2)), 10(2) and 10(4)mugl(-1), was added to the media as well as 1.6mugl(-1) of the sixteen EPA priority PAHs (0.1mugl(-1) of each PAHs). Cu was assayed in solutions, sediments and different plant tissues before and after experiments. After exposure, photosynthetic efficiency and levels of chlorophylls were also measured, indicating that plant stress indicators were identical in all plants independently of the media to which the plants were exposed. PAHs influenced both the soluble Cu fraction and Cu uptake by plants. The amounts of metal accumulated in both roots and stems were significantly higher when the 10(4)mugl(-1) of Cu enriched elutriate was amended with PAHs. Thus, results suggest that PAHs may modify Cu solubility, the Cu sorption by plants and/or the passive penetration of Cu into the root cells. Therefore, the combined effects of different types of pollutants should be taken in consideration when studying the remediation potential of plants, namely in terms of phytoextraction.     

Colorimetric determination of nanomolar concentrations of silicate in natural waters after liquid-liquid extraction using methyl isobutyl ketone

A sensitive solvent extraction method for the determination of nonamolar concentrations of silicate in natural waters is developed. According to the traditional aqueous silicate method, silicomolybdenum blue formed by the reaction between silicate and ammoni- um molydate and reduced by metol-sulfite reagent is extracted by methyl isobutyl ketone. The absorbance can be enhanced substantially up to 10-folds. The detection limit of silicate is 8 nmol/dm^3 , which is one tenth smaller than the traditional method, with the precision of 4.0% at a silicate level of 50 nmol/dm^3 and 3.2% at a silicate level of 6 μmol/dm^3. Comparing the calibration curves in the distilled water and seawater, it can be seen that the salt effect also exists in the extraction method. However, the salt effect is a linear function of the salinity and can be corrected by simple calibration. The proposed method is successfully applied to the determination of silicate in natural waters. Natural concentrations of arsenate, arsenite and phosphate cause negligible interference.     

北斗导航系统应用于测绘地理信息服务的标准化技术体系分析

结合测绘行业的实际需求, 从覆盖范围、数据精度、坐标系统、通信功能、安全可靠性等方面对北斗卫星导航系统技术特点进行了分析;然后从泛在精确定位、智能信息服务、应急服务等几个方面归纳了基于北斗卫星导航系统的测绘地理信息标准体系框架, 并在此框架的标准规范目录中, 明确区分了内容扩展、修改和新制定几类需求, 为基于北斗卫星导航系统的测绘地理信息服务标准化工作提供参考。     

花岗岩地貌及其旅游景观

花岗岩地貌是最重要的自然旅游资源,其形成主要取决于花岗岩体出露地表后上升和剥蚀的速度.当花岗岩体慢速上升,形成花岗岩石蛋地貌;当花岗岩体快速上升时,形成花岗岩峰林地貌;当花岗岩体以较快的速度上升时,则形成以上两种地貌的过渡类型.花岗岩地貌的旅游景观可归并为石蛋及其垒砌造型、石峰及峰林、绝壁及陡崖、一线天、洞穴和石窟、泉和温泉、瀑布等类型.     

登封箕山北麓硅化破碎带含矿地质特征

登封箕山北麓硅化破碎带主要产于上寒武统白云岩中，成群成带分布。矿化严格受地层、岩性、构造条件控制。本文着重硅化破碎带的含矿地质特征、矿化类型、元素组合、异常分布和围岩蚀变等成矿地质条件分析研究，认为太古代变质绿岩和富钾花岗岩类是“矿源层”，其成因应属低温热液充填型。     

Hypoxia in Manila Bay, Philippines during the northeast monsoon

Herein we present results from one of the first extensive bay-wide oceanographic surveys of Manila Bay, wherein 31 stations were sampled during the northeast monsoon (cold and dry season). A band of hypoxic bottom water (dissolved oxygen<2.8 mg/L) spanned the midsection of the bay from east to west. Bottom nitrate concentrations (5.7-16.8 μM; avg. 11.1 μM) and total organic carbon values in sediments (1.7-3.1%; avg. 2.4%) were high in the midsection, which coincided with the band of hypoxic bottom water. Physical processes and site-specific accumulation of organic material likely lead to hypoxic conditions in Manila Bay, even during the northeast monsoon period when the water column is relatively well mixed. The results of this study complement the previously reported widespread hypoxia that occurs during the rainy season. Thus, hypoxia may be pervasive in the bay throughout the year, although it varies in intensity and spatial extent.