区域地球化学特征及其主控因素——对内蒙古珠斯楞地区找矿的意义

在1∶5万水系沉积物测量的基础上,对内蒙古额济纳旗珠斯愣地区的地球化学特征及其主控因素进行初步分析,并对元素分布特征、元素相关性分析、单元素异常与构造之间关系、综合异常与构造之间关系进行了探讨。研究发现,Cu、Au、Sb为区内具一定潜力的找矿元素,与呼伦西白-珠斯楞海尔罕反"S"形构造带南端内、外旋面的转换的珠斯楞海尔罕一带形成一个与断裂构造吻合度较高的、半环性的成矿成晕中心。因而推断,区内具有形成与中酸性侵入岩有关的热液铜多金属矿的可能,其中珠斯楞海尔罕铜金矿和道布青乌苏南北金锑矿2个找矿靶区严格受呼伦西白-珠斯楞海尔罕反"S"形构造的控制。     

Protection of marine birds and turtles at St Brandon’s Rock,Indian Ocean,requires conservation of the entire atoll

A survey of seabirds and turtles at St Brandon’s Rock, 400 km north of Mauritius, was undertaken in 2010. We estimated that 1 084 191 seabirds comprising seven breeding species and excluding non-breeders were present at the archipelago and we counted 279 turtle tracks and nesting pits of green turtles Chelonia mydas. Hawksbill turtles Eretmochelys imbricata were also present. Analyses of 30 different islets that make up the atoll showed that the seabird species mostly partitioned their use of islets based on islet size, with four species preferring larger islets and two species preferring smaller islets. Alien species introduced historically are still present and other threats, such as shipwrecks, remain. We propose conservation and other measures that should adequately protect the birds, turtles and coral reef by treating the atoll as a system.     

AS350B3型直升机在中高山航空物探测量中的优势

中高山地区作业的航空地球物理勘探飞行器需要有高原适航性。通过对比空中国王350ER在起降条件、最大升限、最大续航能力及高原机动能力等特点,提出了在中高山地区的低高度、大比例尺的航空地球物理勘探飞行器的选型原则及飞行方法。通过甘肃某测区的实际测量飞行验证了该原则和方法的可行性。分析结果显示,AS350B3型直升机在中高山地区作业时表现出的实际飞行性能满足在该类型区域低高度、大比例尺的航空地球物理勘探的要求。     

漠河盆地多年冻土区天然气水合物地球化学调查及远景评价

漠河盆地是我国冻土发育的主要地区之一,发育良好的天然气水合物成藏系统,具有天然气水合物形成的良好条件。为了圈定天然气水合物远景区,识别油气聚集体,判别天然气水合物成因,在漠河盆地冻土较发育地区开展了1∶5万天然气水合物地球化学资源调查。结果表明：(1)在森林沼泽景观区,顶空气和荧光光谱指标是天然气水合物勘查的主要指标,借鉴青海木里冻土区天然气水合物地球化学勘查成功的经验,结合AMT、地质等资料分析,元宝山凹陷是天然气水合物较为有利的远景区;(2)岩心样品甲烷碳同位素分析显示,烃类气体分异明显,浅层烃类气体基本为生物气,深部烃类气源主要为混合成因气,个别解吸气为微生物气和热解气;(3)试验性应用了分形-GIS技术,可以细致可靠地进行异常区范围划定,消除干扰因素,有效地圈定水合物远景区。     

Metallogeny of the Baiyangping Lead‐Zinc Polymetallic Ore Concentration Area,Northern Lanping Basin of Yunnan Province,China

The Lanping Basin in the Nujiang‐Lancangjiang‐Jinshajiang (the Sanjiang) area of northeastern margin of the Tibetan Plateau is an important part of eastern Tethyan metallogenic domain. This basin hosts a number of large unique sediment‐hosted Pb‐Zn polymetallic deposits or ore districts, such as the Baiyangping ore concentration area which is one of the representative ore district. The Baiyangping ore concentration area can be divided into the east and west ore belts, which were formed in a folded tectogene of the India‐Asia continental collisional setting and was controlled by a large reverse fault. Field observations reveal that the Mesozoic and Cenozoic sedimentary strata were outcropped in the mining area, and that the orebodies are obviously controlled by faults and hosted in sandstone and carbonate rocks. However, the ore‐forming elements in the east ore belt are mainly Pb‐Zn‐Sr‐Ag, while Pb‐Zn‐Ag‐Cu‐Co elements are dominant in the west ore belt. Comparative analysis of the C‐O‐Sr‐S‐Pb isotopic compositions suggest that both ore belts had a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata; the ore‐forming fluids were originated from formation water and precipitate water, which belonged to basin brine fluid system; sulfur was from organic thermal chemical sulfate reduction and biological sulfate reduction; the metal mineralization material was from sedimentary strata and basement, but the difference of the material source of the basement and the strata and the superimposed mineralization of the west ore belt resulted in the difference of metallogenic elements between the eastern and western metallogenic belts. The Pb‐Zn mineralization age of both ore belts was contemporary and formed in the same metallogenetic event. Both thrust formed at the same time and occurred at the Early Oligocene, which is consistent with the age constrained by field geological relationship.     

Provenance Study of Fe–Ti Oxide Minerals in the Quaternary Sediments in Yichang Area and Its Implication of Formation Time of the Yangtze Three Gorges, China

The Three Gorges are considered to be critical to understand the formation of Yangtze River. Recent research results suggest that the Yangtze Three Gorges was created during the Quaternary but the exact time is debatable. Fe–Ti oxide minerals are seldom used to study sediment provenance, expecially using scanning electron microscopy(SEM), and energy dispersive spectrometer(EDS). In this study, the provenance of Quaternary sediments in Yichang area, which is located to the east of the Yangtze Three Gorges, was investigated by using SEM and EDS to research Fe–Ti oxides. The Panzhihua vanadium titanomagnetite and Emeishan basalt outcrop are located to the west of the Three Gorges. Further, the materials from them are observed in the Quaternary sediments of Yichang area. Fe–Ti oxide minerals from the Huangling granite are observed in the Yunchi and Shanxiyao Formations, which were formed before 0.75 Ma B.P., whereas Fe–Ti oxide minerals from the Huangling granite, Panzhihua vanadium titanomagnetite, and Emeishan basalt are observed in the riverbed and fifth-terrace sediments of the Yangtze River, which were formed after 0.73 Ma B.P.. Thus, we can infer that the Three Gorges formed after the deposition of the Shanxi Formation and before the fifth-terrace; i.e., 0.75–0.73 Ma B.P..     

Ore-forming Fluid and Mineral Source of the Hongshi Copper Deposit in the Kalatage Area, East Tianshan, Xinjiang, NW China

The Hongshi copper deposit is located in the middle of the Kalatage ore district in the northern segment of the Dananhu-Tousuquan island-arc belt in East Tianshan, Xinjiang, NW China. This study analyses the fluid inclusions and H, O, and S stable isotopic compositions of the deposit. The fluid-inclusion data indicate that aqueous fluid inclusions were trapped in chalcopyrite-bearing quartz veins in the gangue minerals. The homogenization temperatures range from 108°C to 299°C, and the salinities range from 0.5% to 11.8%, indicating medium to low temperatures and salinities. The trapping pressures range from 34.5 MPa to 56.8 MPa. The δ18OH2O values and δD values of the fluid range from ?6.94‰ to ?5.33‰ and from ?95.31‰ to ?48.20‰, respectively. The H and O isotopic data indicate that the ore-forming fluid derived from a mix of magmatic water and meteoric water and that meteoric water played a significant role. The S isotopic composition of pyrite ranges from 1.9‰ to 5.2‰, with an average value of 3.1‰, and the S isotopic composition of chalcopyrite ranges from ?0.9‰ to 4‰, with an average value of 1.36‰, implying that the S in the ore-forming materials was derived from the mantle. The introduction of meteoric water decreased the temperature, volatile content, and pressure, resulting in immiscibility. These factors may have been the major causes of the mineralization of the Hongshi copper deposit. Based on all the geologic and fluid characteristics, we conclude that the Hongshi copper deposit is an epithermal deposit.     

钻探-物探测井技术在覆盖区填图中的应用研究

钻探作为获取深部地质信息的最直接手段,可查明第四纪地层序列,确定基岩顶面埋深与起伏、验证推测模型、研究地质构造、圈定地质体间的重要接触关系,服务于覆盖区填图。物探测井是一种科学有效的井内探测手段,利用特定的岩性或岩性组合对应着特定的测井参数组合的特点,利用测井参数组合可识别地层的岩性、确定地层的深度与厚度,可进行地层划分对比等。钻探-物探测井技术的综合利用,将提高覆盖区勘探效率,降低勘探成本,为下一步开展的覆盖区填图工作提供技术方法支撑。     

山东黄金西岭勘查区深部勘探孔防斜与纠斜措施

西岭勘查区金矿找矿工作已全面进入勘探阶段,勘查区网度为80 m×80 m,对于钻孔质量要求十分严格：终孔靶点偏差不超过勘探网度的四分之一,即不超过20 m。对于西岭勘查区设计孔深均超过1500 m（部分钻孔设计甚至超过2500 m）的钻孔而言,这种要求远远超过地质岩心钻探规程要求。山东黄金地勘公司根据多年深孔施工经验,在防斜与纠斜方面均取得了一些突破,自主研发了钻具扶正器、独创了钻孔纠斜法,形成了一套实用的钻孔质量保证措施。     

上海砂性软土地层水平定向钻进泥浆性能调控技术

上海地区水平定向钻进铺管（HDD）钻遇不易成孔的砂性软土的概率甚高,这种地层对泥浆性能有特殊要求。但目前普遍使用的复配型增效商品土粉基调相近,难以就大量工程个案恰如其分地发挥关键功效。为此,论述了该类工程环境下泥浆性能设计要点,分析了材料添配的作用机理,重点给出了泥浆密度、粘度、切力以及失水量等参数调控的宜于实用的若干配材技术,以提供相类似工程条件下泥浆运用的可参考方法。