粤东典型海湾表层沉积物Cd的分布及其潜在生态危害评价*

对粤东海域5个典型海湾64个表层沉积物样进行了重金属Cd含量的测定,分析探讨了其空间分布特征及其主要影响因素,并以南海陆架区Cd含量为背景值计算了粤东5个海湾表层沉积物Cd的潜在生态危害系数。结果显示,柘林湾、汕头湾、汕尾湾、大亚湾和大鹏湾表层沉积物Cd的含量范围分别为0.04—0.58、0.06—6.63、0.06—0.11、0.04—0.20、0.08—0.15 mg·kg?1,其分布表现为：柘林湾养殖区和三百门附近海域以及汕头湾拦沙堤末端海域和好望角附近海域Cd含量高于其他海区,汕尾湾的Cd含量由近岸向外海、西部到东部增加,而大亚湾和大鹏湾外湾含量高。重金属输入和水动力条件是控制 Cd 分布的决定性因素。生态危害评价表明,养殖区、三百门附近海域、拦沙堤末端海域和好望角附近海域Cd污染达到了中等甚至很强的生态危害水平,污染比较严重。来自入海河流携带工业污染物注入、沿岸排污、水产养殖沉降、产业转移人为排放和金属矿床开采释放的 Cd 已造成了近海环境的污染,应当引起相关部门的重视。     

Clay mineral distribution in surface sediments of the South China Sea and its significance for in sediment sources and transport

Clay minerals of surface sediments in the South China Sea (SCS) are analyzed with X-ray diffraction, and their transport is explored with a grain size trend analysis (GSTA) model. Results show that clay mineral types in various sedimentary environments have different sediment sources and transport routes. Sediments in the northern SCS (north of 20°N) between the southwest of Taiwan Island and the outer mouth of the Pearl River have high contents of illite and chlorite, which are derived mainly from sediments on Taiwan Island and/or the Yangtze River. Sediments from the Pearl River are characterized by high kaolinite and low smectite content, and most are distributed in the area between the mouth of the Pearl River and northeast of Hainan Island and transported vertically from the continental shelf to the slope. Characterized by high illite content, sediments from Kalimantan Island are transported toward the Nansha Trough. Sediments from Luzon Island are related with volcanic materials, and are transported westwards according to smectite distribution. On the Sunda Shelf, sediments from the Mekong River are transported southeast in the north while sediments from the Indonesian islands are transported northward in the south. Ascertaining surface sediment sources and their transport routes will not only improve understanding of modern transportation and depositional processes, but also aid paleoenvironmental and paleoclimatic analysis of the SCS.     

Clay mineral distribution in surface sediments of the South China Sea and its significance for in sediment sources and transport

Clay minerals of surface sediments in the South China Sea (SCS) are analyzed with X-ray diffraction, and their transport is explored with a grain size trend analysis (GSTA) model. Results show that clay mineral types in various sedimentary environments have different sediment sources and transport routes. Sediments in the northern SCS (north of 20°N) between the southwest of Taiwan Island and the outer mouth of the Pearl River have high contents of illite and chlorite, which are derived mainly from sediments on Taiwan Island and/or the Yangtze River. Sediments from the Pearl River are characterized by high kaolinite and low smectite content, and most are distributed in the area between the mouth of the Pearl River and northeast of Hainan Island and transported vertically from the continental shelf to the slope. Characterized by high illite content, sediments from Kalimantan Island are transported toward the Nansha Trough. Sediments from Luzon Island are related with volcanic materials, and are transported westwards according to smectite distribution. On the Sunda Shelf, sediments from the Mekong River are transported southeast in the north while sediments from the Indonesian islands are transported northward in the south. Ascertaining surface sediment sources and their transport routes will not only improve understanding of modern transportation and depositional processes, but also aid paleoenvironmental and paleoclimatic analysis of the SCS.     

珠江三角洲两工业区土壤环境磁学初步研究

对珠江三角洲东莞石龙、顺德容奇—桂洲两工业区的土壤磁性进行初步研究,获得两地区6个柱样及48个表层样品的磁化率（X）和天然剩余磁化强度（NRM）的结果,石龙地区的X,NRM的垂直变化平均值分别为10．86×10－6SI和6．73×10-6A·m－1,顺德容桂地区X,NRM的垂直变化平均值分别为96．84×10－6SI和31．49×10－6A·m－1,表层样容桂地区X和NRM值大于石龙地区,表明两地区土壤的磁载体存在明显的差异,磁记录大致能反映现代环境的信息。     

全球气候变暖对广州市土壤重金属污染的影响及其对策

针对重金属污染的特殊性和危害性以及广州市土壤重金属污染的现状,分析了全球气候变暖对广州市土壤重金属污染的可能影响,并根据新近提出的“化学定时炸弹”（ＣＴＢ）的新概念（思想）,初步提出了动态监控重金属污染以防止灾难性事件发生的基本对策。     

构造成因矿物学及其研究意义

通过矿物研究构造乃是矿物学的新课题之一。随着构造地球化学的提出和发展,显微、超显微技术在构造地质学中的广泛应用,构造成因矿物学提出的主客观条件当然也日趋成熟。 1、构造成因矿物学的科学依据:大量研究表明,在许多矿物(尤其是主造岩矿物)中含有丰富多彩的构造信息。如随着温度和应变率的降低,石英的位错滑移从底面(a)转变为柱面(c)方向;在10.7～15.4GPa压力下,晶质的Ca(OH)_2(羟钙石)转化为玻璃质,松压过程中(3.6～5.1GPa)玻璃质转化为晶质;上地幔的剪切软化作用产生镁橄榄石的变型体——     

天然矿物自然铝的研究进展

综述了国内外自然铝的发现与研究史;自然铝的物理性质和颗粒形态、元素组成及含量、晶体结构参数等特征;自然铝的成因模式。自然铝主要见于老的火山和热液矿石中,或现代和中-新生代的海底活动构造带（如转换断层、中央海隆以及弧后扩张中心）的海洋沉积物中,有地幔碳热还原、海底热液内生和陆地表生置换等3种成因模式。     

珠江口沉积物中重金属及其相态分布特征

分析了在珠江口采集的21个表层柱状沉积物样品重金属(Cu、Pb、Zn、Cr、Cd、As、Hg)的分布特征，并采用连续提取法，首次较系统地对该区沉积物中重金属元素的相态进行了研究。结果表明，珠江口表层沉积物中Zn、Cr、Cu、Cd等重金属含量呈现由西北逐渐向东南递减的变化特点，而Pb、As、Hg等重金属元素的含量分布无明显规律。重金属的相态分布表现为，Cu、Cd以吸附相为主，Cr、Hg以铁锰氧化物和有机结合相为主，Pb、Zn和As则表现为相对较为均匀地分布在3个或4个相态中，其中Pb以有机相稍占优势，Zn以铁锰氧化物相稍占优势，As则以水相稍占优势。重金属含量及相态分布的影响因素主要为污染源的排放(人为因素)和珠江口的水动力条件(自然因素)，如强径流和弱潮所引起的沉积物粒度组成、海水、底质的盐度以及pH、Eh等。     

南海北部大陆坡冷泉碳酸盐结核的发现:天然气水合物新证据

南海北部大陆坡是我国天然气水合物调查和研究的重点海域,目前已发现了多处水合物存在的地球物理、地球化学、海底地貌特征等证据。冷泉碳酸盐的析出是天然气水合物冷泉存在的重要明显标志之一,已成为南海北部继地球物理BSR标志后发现的与水合物存在相关的另一重要证据。中国科