扎村金矿床地质特征

本文根据兰坪-思茅中生代坳陷地质构造演化并结合区域地球物理场,论证本区(巍山金矿带)含矿热液形成与元素迁移富集成矿条件是喜马拉雅构造运动及岩浆活动。扎村金矿床是巍山金矿带中已发现的唯一金矿床,赋存在上三叠统三合洞组层间破碎带的断裂带中。层间破碎带很宽,其内形成上、中、下三“层”矿体。矿体多呈透镜体,少数似层状。矿石以破碎岩型、角砾岩型为主。矿化带虽厚,但品位低。金矿化强弱与黄铁矿化、硅化、碳酸盐化呈正相关。金矿化主要呈微细粒自然金以晶隙金(含粒间金)和裂隙金产出。根据稳定同位素、包裹体、稀土和微量元素等数据分析,含金流体主要与深源的岩浆水(含少量变质水)和地下热(卤)水组成的混合热液有关。成矿温度以230-290℃为主。据水云母Rb/Sr法年龄46.5Ma,成矿时代为喜马拉雅期,可能与同期斑岩的岩浆活动有密切的成因联系。扎村金矿床系多期、多源、多阶段、多因素迭加而成,据黄铁矿的Co/Ni比值,可判别为从地下卤水到岩浆热液类型。     

安达曼海的热收支分析及其水交换研究

The characteristics of the T/S structures, water mass exchange and deep circulation in the Andaman Sea are investigated based on the simulation from a high-resolution general circulation model(MITgcm). The results show that, below 1 000 m, the water mass is saltier, warmer and more homogeneous in the Andaman Sea than that in the Bay of Bengal, attributing to the strong vertical mixing at the depth of ～1 800 m. The water mass exchange between the Andaman Sea and the Bay of Bengal goes through three major channels, which manifests itself as follows: the northern channel(Preparis Channel) is the main passage of water mass transport from the Bay of Bengal to the Andaman Sea, whereas the Middle Channel(the south of Andaman Islands and the north of Nicobar Islands) has an opposite transport; the southern channel(Great Channel) features with a four-layer water exchange which results in the least net transport among the three channels; all the transports through the three channels have an intra-annual variation with a period of half a year. At 1 000-m depth, the entire Andaman Sea is occupied by a cyclonic circulation in January and July while by an anticyclonic one in April and October. The semiannual cycle found in both the deep circulation and water mass exchange is likely associated with the downwelling eastward-propagating Kelvin waves induced by the semiannual westerly component in the equatorial Indian Ocean during intermonsoon seasons.     

云南昌宁早泥盆世地层的发现

<正> 云南省西部昌宁城西南近南北向分布的一套碎屑岩,以往被划入昌宁—永德鱼塘寨的下石炭统。近年来找到了早泥盆世的笔石、竹节石、植物等,从而证明了这一套碎屑岩的时代属于早泥盆世。 该地层由昌宁城西,经凤庆营盘、永德大雪山及其以南地区延展,产丰富的动、植物化石,为我国泥盆系的划分对比提供了重要的新资料。     

具有多种胞外酶的对虾肠道黏附菌的分离和鉴定

用对虾饲料培养基从健康凡纳滨对虾肠道分离出500株黏附细菌,以产淀粉酶、脂肪酶和蛋白酶能力为指标,筛选出产该3种消化酶的细菌90株,占总菌株的18%.对其中生长较快的69株进行16S rDNA 基因测序,确定其分类地位.结果显示,69株菌分别属于不动杆菌属(Acinetobacter)、芽孢杆菌属(Bacillus)、葡萄球菌属(Staphylococcus)、假交替单胞菌属(Pseudoalteromonas)、气单胞菌属(Aeromonas)、嗜盐单胞菌属(Halomonas)、利斯顿氏菌属(Listonella)、莫拉氏菌属(Moraxella)等,其中数量最多是芽胞杆菌属,占鉴定细菌总数的53.62%,数量最少是气单胞菌属和嗜盐单胞菌属,均占鉴定细菌总数的2.90%.表明对虾肠道黏附菌群中具有较多能分泌多种消化酶的细菌,可进一步开发为促进对虾消化功能的益生菌     

山东蓬莱地区金矿成矿背景与成矿规律探讨

在系统分析蓬莱地区各矿山已有地质资料及近年来该区金成矿理论研究的基础上,对蓬莱地区区域地质背景进行了分析,认为蓬莱地区金成矿为一系列构造、岩浆活动叠加,中生代集中成矿的结果。蚀变、矿化分带与构造分带协调对应,呈现三位一体;矿床空间分布具有一定规律性,断裂构造拐弯或交会部位赋矿,构造倾角变化部位赋矿,矿体尖灭再现、分枝复合规律,矿体侧伏规律;各种类型金矿床在时空分布和成因上密切相关,由于控矿条件和成矿环境的异同,形成不同类型矿床和同种类型矿床的组合。