湘南宝山地区燕山期成矿花岗岩岩浆作用研究

本文对湘南宝山花岗闪长斑岩进行了系统的锆石和磷灰石U-Pb定年、岩石地球化学以及锆石Hf同位素研究,并探讨了宝山花岗闪长斑岩的岩石成因和构造意义。锆石和磷灰石的LA-ICP-MS U-Pb定年显示,宝山花岗闪长斑岩的成岩年龄为160Ma。综合元素和同位素地球化学证据,宝山花岗闪长斑岩的成因可能为新生地壳与古老地壳的混合熔融,同时宝山花岗闪长斑岩中发现的890±20Ma的继承锆石,验证了新元古代新生地壳的参与。磷灰石的主微量元素研究显示花岗闪长斑岩具有较高的氧逸度和Cl含量,Sr/Th比值具有较大变化,而La/Sm比值变化不大等特征,表明形成花岗闪长斑岩岩浆的母岩受到俯冲板片脱水形成的流体交代作用影响。在上述过程中,富含Cl和H₂O的流体从板片中释放出来,引发地幔楔熔融,并对矿床中成矿金属元素进行提取。由于古太平洋板块俯冲引发的伸展-减薄运动,在地幔上涌过程中,新元古代新生地壳发生部分熔融,这些高温岩浆底侵老地壳源区,诱发老地壳部分熔融,进而发生了强烈的壳-壳混合作用,产生花岗闪长质岩浆。

     

大平山铜矿毒砂单矿物扫描电镜分析

大平山铜矿床位于南京市江宁区横溪镇西侧,矿石中有用组分除铜以外,还伴生有As、Zn、Ag、Au、Co和Ni等元素,其中As元素质量分数较高,局部达0.2%～0.9%。通过显微观察和扫描电镜能谱分析,发现大平山铜矿矿石中As元素主要以硫化物形式,呈毒砂独立矿物以自形—半自形粒状、他形粒状赋存于矿石中。赋存方式主要为：以独立矿物呈稀疏浸染状分布于矿石中,局部呈条带状和中等稠密浸染状分布于矿石中;以交代方式与黄铁矿和黄铜矿共生于矿石中,但毒砂形成晚于黄铁矿和黄铜矿。     

云南富宁县牛场钛铁砂矿矿床成因及富集规律

富宁地区里达断裂东侧出露大量的中三叠世印支期第一期第四亚期侵入的辉长辉绿岩体,经过漫长的风化、水解作用,岩体岩石结构构造遭受破坏,钛铁矿、钛磁铁矿、金红石等矿石矿物从原岩中彻底解离,从而形成了易开采利用的辉长辉绿岩风化壳型钛铁矿（砂）矿床.     

激电中梯测量在龙湾套铜矿找矿中的应用

泗水县龙湾套铜矿为岩浆熔离型铜镍硫化物矿床,通过激电中梯测量圈定了若干激电异常,经工程验证,不但在这些异常中发现了9个铜矿体,而且各矿体的形态,规模与异常的形态,规模大致吻合.     

Holocene alluvial environments at Barking,Lower Thames Valley (London,UK)

Deposit modelling based on archived borehole logs supplemented by a small number of dedicated boreholes is used to reconstruct the main boundary surfaces and the thickness of the main sediment units within the succession of Holocene alluvial deposits underlying the floodplain in the Barking Reach of the Lower Thames Valley. The basis of the modelling exercise is discussed and the models are used to assess the significance of floodplain relief in determining patterns of sedimentation. This evidence is combined with the results of biostratigraphical and geochronological investigations to reconstruct the environmental conditions associated with each successive stage of floodplain aggradation. The two main factors affecting the history and spatial pattern of Holocene sedimentation are shown to be the regional behaviour of relative sea level and the pattern of relief on the surface of the sub-alluvial, Late Devensian Shepperton Gravel. As is generally the case in the Lower Thames Valley, three main stratigraphic units are recognised, the Lower Alluvium, a peat bed broadly equivalent to the Tilbury III peat of Devoy (1979) and an Upper Alluvium. There is no evidence to suggest that the floodplain was substantially re-shaped by erosion during the Holocene. Instead, the relief inherited from the Shepperton Gravel surface was gradually buried either by the accumulation of peat or by deposition of fine-grained sediment from suspension in standing or slow-moving water. The palaeoenvironmental record from Barking confirms important details of the Holocene record observed elsewhere in the Lower Thames Valley, including the presence of Taxus in the valley-floor fen carr woodland between about 5000 and 4000 cal BP, and the subsequent growth of Ulmus on the peat surface.     

云南威信李子埂煤矿突水治理方案分析

煤矿掘进过程中揭露了小断裂,断裂活化后,煤层下覆岩溶水涌入;矿井突水导致了龙洞坝泉暂时性断流.介绍了突水治理方案：采用物探方法寻找突水井巷,用“地表钻孔注砼法”封堵突水段井巷.该方案能彻底封堵本次突水的导水断裂和龙洞坝泉的水力联系,使龙洞坝泉涌水不会再受本次突水影响,同时,也能解除煤矿受本次突水的危害,为煤矿下一步的恢复工作奠定基础.     

矿床学研究的历史观

矿床是地球历史演化的产物,每一个矿床都有其特殊的形成史和变化保存史.矿床学的基本内容应是矿床成因和矿床变化保存两个方面.以历史演化的观点查明矿床形成-变化-保存全过程,有利于矿床学理论水平的提高,也是矿产勘查工作的需要.提出历史观开展矿床学研究的三个层次:①单个矿床形成变化与保存;②区域成矿演化;③全球成矿演化.单个矿...     

浙江桐庐冷坞二叠纪生物礁的发育模式

礁体底部具脉状层理的潮坪相碎屑沉积,礁体内部藻叠层岩夹层的存在,及礁体上部为煤系地层覆盖等都表明冷坞生物礁是一个典型的二叠纪岸礁;海绵骨架岩的存在表明它是个骨架型岸礁。     

马关八梅喷流沉积铅锌锡铜金多金属矿床

矿床产于中寒武田蓬组地层中,受地层、沉积岩相、变质岩相控制。围岩蚀变为黄铁矿化、锰矿化、碳酸盐化、硅化。矿床成因为海底含矿热卤水喷流沉积型。     

A Preliminary Review on the Metallogeny of Pb-Zn Deposits in China

Lead and zinc resources are abundant in China, with the reserves of 100 million tons ranking only second in the world. There are more than 3000 lead-zinc mine areas nationwide. The classification of lead-zinc (Pb-Zn) deposits has been a highly controversial issue. From the standpoint of evaluating the potential of mineral resources, we construct a Pb-Zn deposit predictive type of classification scheme, and propose a Pb-Zn deposit comprehensive classification scheme (including 5 classes and 13 sub-types) that regards mineralization as the primary factor and the ore rock as secondary. According to the temporal and spatial distribution of Pb-Zn deposits, we conclude that a multi-period, multi-cycle orogenic environment is the most favorable for lead-zinc deposit growth, that the Proterozoic is the major eon for the growth of igneous-type deposits, the Paleozoic is an important development era for sedimentary Pb-Zn deposits, and the Mesozoic and Cenozoic are the heyday eras of magmatic type lead-zinc deposits. On this basis, we analyse the relationship between tectonic evolution and Pb-Zn metallogenic, and propose that the key factors determining geological mineralization are the metallogenic epoch of mineralization and tectonic environment, which determine the temporal and spatial distribution.