On the basis of the actual material and data from three gold deposits(Changkeng, Gaolong and Guoti) in Guangdong and Guangxi provinces of China, we suggested that within the sediment-hosted micro-disseminated-type(Carlin-type) gold deposits, there is a subtype which could be called silicalite-type gold deposit. Its main gold-bearing rocks are carbonaceous silicalites, which have stratiform occurrence and are composed of tiny quartz and carbonaceous matter principally. The gold exists in submicroscopic and disseminated form. This kind of gold deposits possesses the principal characteristics of general sediment-hosted micro-disseminated gold deposits, but does not belong to deuterogenic hydrothermal alteration-metasomatism origin. They were mainly formed by sedimentary exhalation, meanwhile, could be mixed with certain quantity of organo-sedimentary and normal marine sedimentary materials. It is proposed that sediment-hosted micro-disseminated gold deposits have varied geneses, including deuterogenic hydrothermal origin, sedimentary exhalation origin and other origins. The guideline for searching the silicalite-type gold deposits would be obtained from thinking about the idea of the “sedimentary exhalation-syngenetic metallogenesis”. It is recommended to re-study the so-called “silicified rocks” in certain sediment-hosted micro-disseminated gold mining areas in order to find out their true attribution. Finally, the southern China is one of the best prospecting areas to search silicalite-type gold deposits.

Some radiolarian fossils were discovered two times in the carbonaceous silicalites, the major gold-bearing rocks in the Changkeng gold-silver deposit. The geologic period of the fossils may belong to Early Carboniferous epoch. Meanwhile, some biological remains were also found in this kind of rocks, such as quartz ring, quartz loop, quartz monocrystal sphere, quartz polycrystal sphere, biological relic and homologous organic texture. Based on these facts, it is considered that these carbonaceous silicalites contained some microbiofossils formerly, generated in sea basin and belong to sedimentary origin. They are strong evidences to prove that the carbonaceous silicalites derived from sedimentary exhalation, and not from hydrothermal alteration-metasomatism. Besides, these facts indicate that some biological material joined in the sedimentary exhalation course, and sedimentary exhalation and organosedimentation could mix each other at a place. They also show that the Changkeng deposit was formed in an extensional, starved and relatively deep-water basin. Finally, a doubt is put forward that whether the lithostratigraphic unit of the strata in Changkeng area is right or not.

对矿区70个见矿钻孔的金银矿化进行了统计研究,包括矿化的厚度分布,见矿次数,合计见矿厚度和平均矿化厚度.矿化主要出现于硅质岩类中,但非硅质岩类的矿化也不可忽视.各种岩性有其自己的成矿趋势和特点.金矿化较厚,高品级矿石比例大,矿化品级与厚度基本上呈正向消长,成矿与厚层角砾状硅质岩的专属性关系密切.金矿化的规律呈现得较清晰.银矿化在这些方面不如金矿化,缺乏清晰的规律.出现上述情况的原因与矿床发育两种矿化(早期热水沉积层状矿化和后期热液叠加脉状矿化)有关.

广东长坑银金矿区的地层,原认为由下石炭统及上三叠统组成,两者呈断层接触.近来,在原定为梓门桥组的硅质岩中发现了晚二叠世放射虫化石;在小坪组所夹的灰岩中发现有早石炭世有孔虫化石;在某些地段还发现"梓门桥组"硅质岩与"小坪组"整合接触.据此认为矿区内可能有中石炭世至中三叠世地层存在.目前对上述新发现的解释均不够圆满,因此对长坑矿区的地层学有必要深入研究,无论研究结论如何,都将对矿区的地层划分、地质构造解释、成矿理论和今后进一步找矿的认识等产生重要影响.

对长坑金银矿床的化学组成、同位素特征、流体性质、成矿物理化学条件和机理的系统研究表明,与矿化最密切的硅质岩应主要为热液交代成因;金、银矿体的稀土和微量元素特征既有共性又有异性;矿床的硫、铅、碳、锶同位素组成特征反映它们均为壳源物质或沉积成因;成矿流体相对富Ca、K,主要来自演化了的加热大气水或建造水;矿床形成于中低温的热液条件,矿化机制包括热液沸腾、流体混合与水岩反应.总之,长坑矿床为微细浸染型金矿与碳酸盐岩交代型银矿构成的新颖矿床组合,金、银矿体是统一的热液作用在不同的成矿环境和控矿条件下的产物,它们与区域内的铅锌(银)矿床应属于一个成矿系列.

Diaminoglyoxime was reacted in water at 150–400°C and at 27.5 MPa pressure in metal Ti tubing reactor. Experimental results indicate that, diaminoglyoxime can be converted into NH 3 and CO 2 , either through direct hydrolysis or through pyrolysis and polymerization, and then further hydrolysis. The possible reaction mechanism is nucleophilic addition of water.

In order to explore processing conditions and reacting mechanism of priority organic wastes, diaminoglyoxime, cyanamide and melamine which were used as starting materials in this paper were conducted hydrothermal experimental studies under conditions at temperatures of 150-400 °C and pressures of 100-700×105Pa. H2O2 was added in some runs of melamine. Experimental results indicated that under hydrothermal conditions, especially in supercritical water, diaminoglyoxime and cyanamide can be converted into NH3 and CO2, either through direct hydrolysis or through pyrolysis. In the second case, they firstly polymerize into a mixture of higher molecular weight cyclic azines before ultimately hydrolysis. Supercritical water can efficiently destroy those organic wastes which cantain hazardous or toxic materials and can transform them into nonpoisonous NH3 and CO2, etc. To process those hydrothermally stable organic wastes in hydrothermolysis, a few oxidizers can be appropriately added so that priority organic wastes are able to transform more quickly, more completely. Prossible mechanism of hydrolysis reaction is nucleophilic addition of water.

在温度 150～ 4 0 0℃ ,压力 2 7 5MPa的条件下 ,通过二氨基乙二肟在水热环境 ,尤其在超临界水中的反应化学实验结果表明 ,二氨基乙二肟既可以通过热解作用而聚合成较高分子量的氮杂环混合物 ,进而水解转化成CO2 和NH3,也可以直接发生水解作用生成CO2 和NH3:产物在分配主要取决于温度、压力、反应时间、pH和某些复杂的化学平衡因素 ;水解反应的可能机制是水的亲核加合 ,分子间键的断裂和重新结合 ,可能首先发生于不饱和键位置上 .

长坑金银矿床方解石的δ13C值为-3．23‰，方解石和石英的δ18O分别为8．64‰～18．61‰和9．60‰～13．0‰，其范围与其它卡林型金矿相似。结合大本（Ohmoto）模式的理论分析，认为成矿热液的总联同位素组成可大致取为-2‰～－17‰，即碳主要来自地层中的沉积碳酸盐，部分来自有机碳。推导出水岩交换过程中流体氢、氧同位素演化的一般性协变方程并进行了理论模拟，认为成矿流体以燕山晚期一第三纪的加热大气降水或建造水为主。

Cyanamide, dicyandiamide, and the related cyclic azines (melamine, ammeline, ammelide, and cyanuric acid) were reacted in water at 100–300 °C in a sealed 316 SS tube (275 bar) for the purpose of characterizing the hydrothermolysis chemistry of cyanamide. The conversion of cyanamide to dicyandiamide dominates at 100–175 °C. At 175–250 °C, when the reaction times are shorter than 15 min, the major pathway is hydrolysis of the cyanamide-dicyandiamide mixture to CO2 and NH3. A minor pathway is cyclization to higher azines (melamine, ammeline, ammelide and cyanuric acid). Above about 225 °C, hydrolysis of these cyclic azines to aqueous NH3 and CO2 occurs in a relative ratio which depends on the particular cyclic azine, and, to an extent, which increases with temperature. At 300 °C the conversion of all compounds to CO2 and NH3 is complete in 10 min. The hydrothermolysis chemistry of cyanamide and urea are compared.