朝鲜半岛及华北上元古界-古生界沉积序列与碎屑锆石年代学记录及其构造属性分析

通过地层结构、沉积序列与碎屑锆石年代学记录等三方面的成因分析和区域对比,本文进一步探究了中-朝地块新元古代-古生代的构造属性及演化信息。研究指出,朝鲜半岛平南盆地、太白山盆地以及华北地块内部,其地层结构-沉积相序主要以寒武-奥陶系内陆架碳酸盐岩沉积、志留-泥盆系缺失、中上石炭统-二叠系海陆交互相含煤沉积为特征,并具有可对比的1.85Ga、2.5Ga以及1.15Ga、1.6Ga等碎屑锆石年龄峰值。而在临津江带、沃川带以及华北东南缘,则以泥盆-石炭系泥岩/片岩、中基性火山岩及火山碎屑岩、碳酸盐岩(透镜体)混杂发育为特征,总体显示外陆架沉积环境,且具有可对比的与地层时代接近的最小碎屑锆石年龄,这也是对沉积期较强构造-岩浆活动的反映。综合地层结构、相序、碎屑锆石年龄组成以及聚煤记录,提出朝鲜半岛与华北应属于统一的一级构造单元,即"中-朝板块";但朝鲜半岛西南部及华北东南缘毗邻板块边缘,因此其地层-沉积记录与板内存在差异,简单的一致性模式并不适用。     

Application research of enhanced in-situ micro-ecological remediation of petroleum contaminated soil

Experimental study of enhanced in-situ micro-ecological remediation of petroleum contaminated loess soil was carried out in Zhongyuan oil production areas, and the enhanced in-situ micro-ecological remediation technique includes optimistic in-situ microbial communities, physical chemistry methods, alfalfa planting and regulation of soil environmental elements. Experiments showed that the oil content in the contaminated soil with oil content about 2 898.25 mg/kg can be reduced about 98.61% after in-situ micro-ecological remediation for 99 days, which demonstrated the effectiveness of in-situ micro-ecological remediation methods for petroleum contaminated soil in central plains of China, and explored the practical and feasible application of these methods.     

New tectonic map of Northern-Central-Eastern Asia:Position and evolution of Mesozoic sedimentary basins

The beginning of the XXI century was marked a new rising of the international tectonic cartography as a result of analysis and synthesis of a huge volume of geological information obtained for the territory of Asia especially during the last 30 years. The previous tectonic maps for Asia were created in the 1960 s--1970 s of the last century. Since that time,the national geological surveys have compiled tectonic maps exclusively in the limits of their own state boundaries. The international cooperation of five countries since 2002( Russia,China,Mongolia,Kazakhstan and Republic of Korea) gave a unique possibility to join the data into a united cartographic form as Atlas of Geological Maps( since 2002-Atlas of Geological Maps of Central Asia and since 2007-Atlas of Geological Maps of Northern-Central-Eastern Asia). Both atlases include four maps: geological,tectonic,metallogenic,and energy resources. Tectonic Map of Northern-Central-Eastern Asia and Adjacent Areas at scale 1 ∶ 2 500 000 was the key map for further compilation of the metallogenic and energy resources( coal,oil and gas) maps. By this reason,special attention was given to showing the structure and composition of the Mesozoic sedimentary basins in Northern-Central- Eastern Asia as the most perspective structures for oil-and-gas and coal prospect.     

Metallogenic Mechanism and Tectonic Setting of Tungsten Mineralization in the Yangbishan Deposit in Northeastern China

The Yangbishan iron–tungsten deposit in the Shuangyashan area of Heilongjiang Province is located in the center of the Jiamusi Massif in northeastern China. The rare earth element and trace element compositions of the scheelite show that it formed in a reducing environment and inherited the rare earth element features of the ore-forming fluid. The geochemical characteristics of the gneissic granite associated with the tungsten mineralization show that the magma formed in this reducing environment and originated from the partial melting of metamorphosed shale that contained organic carbon and was enriched with tungsten. In addition, in situ Hf isotopic analysis of zircons from the gneissic granite indicates that they probably originated from the partial melting of a predominantly Paleo–Mesoproterozoic crustal source. According to LA-ICP-MS zircon dating, the Yangbishan orerelated gneissic granite has an Early Paleozoic crystallization age of 520.6 ± 2.8 Ma. This study, together with previous data, indicates that the massifs of northeastern China, including Erguna, Xing'an, Songliao, Jiamusi, and Khanka massifs, belonged to an orogenic belt that existed along the southern margin of the Siberian Craton during the late Pan-African period. The significant continental movements of this orogeny resulted in widespread magmatic activity in northeastern China from 530 Ma to 470 Ma under a tectonic setting that transitioned from compressional syn-collision to extensional postcollision.     

Geochemical and Petrological Studies on the Early Carboniferous Sidingheishan Mafic–Ultramafic Iintrusion in the Southern Margin of the Central Asian Orogenic Belt, NW China

The Sidingheishan mafic-ultramafic intrusion is located in the eastern part of the Northern Tianshan Mountain, along the southern margin of the Central Asian Orogenic Belt in northern Xinjiang autonomous region of China. The Sidingheishan intrusion is mainly composed of wehrlite, olivine websterite, olivine gabbro, gabbro and hornblende gabbro. At least two pulses of magma were involved in the formation of the intrusion. The first pulse of magma produced an olivine-free unit and the second pulse produced an olivine-bearing unit. The magmas intruded the Devonian granites and granodiorites.An age of 351.4±5.8 Ma(Early Carboniferous) for the Sidingheishan intrusion has been determined by U-Pb SHRIMP analysis of zircon grains separated from the olivine gabbro unit. A U-Pb age of 359.2±6.4 Ma from the gabbro unit has been obtained by LA-ICP-MS. Olivine of the Sidingheishan intrusion reaches 82.52 mole% Fo and 1414 ppm Ni. On the basis of olivine-liquid equilibria, it has been calculated that the MgO and FeO included in the parental magma of a wehrlite sample were approximately10.43 wt% and 13.14 wt%, respectively. The Sidingheishan intrusive rocks are characterized by moderate enrichments in Th and Sm, slight enrichments in light REE, and depletions in Nb, Ta, Zr and Hf. The ε_(Nd)(t) values in the rock units vary from +6.70 to +9.64, and initial ~(87)Sr/~(86)Sr ratios range between 0.7035 and0.7042. Initial ~(206)Pb/~(204)Pb, ~(207)Pb/~(204)Pb and ~(208)Pb/~(204)Pb values fall in the ranges of 17.23-17.91,15.45-15.54 and 37.54-38.09 respectively. These characteristics are collectively similar to the Heishan intrusion and the Early Carboniferous subduction related volcanic rocks in the Santanghu Basin, North Tianshan and Beishan area. The low(La/Gd)_(PM) values between 0.26 and 1.77 indicate that the magma of the Sidingheishan intrusion was most likely derived from a depleted spinel-peridotite mantle.(Th/Nb)_(PM)ratios from 0.59 to 20.25 indicate contamination of the parental magma in the upper crust.Crystallization modeling methods suggest that the parental magma of the Sidingheishan intrusion was generated by flush melting of the asthenosphere and subsequently there was about 10 vol%contamination from a granitic melt. This was followed by about 5 vol% assimilation of upper crustal rocks. Thus, the high-Mg basaltic parental magma of Sidingheishan intrusion is interpreted to have formed from partial melting of the asthenosphere during the break-off of a subducted slab.     

油铀兼探的找矿思路在松辽盆地的应用——以中央拗陷区南部为例

以"油铀兼探"的找矿思路,带动松辽盆地中南部开展砂岩型铀矿调查选区及钻探验证工作.将异常强度250 API和450 API确定为划分潜在铀矿孔、潜在铀矿化孔和正常孔的关键技术指标,对中央拗陷区南部1572个钻孔进行异常筛查工作.排查发现潜在铀矿孔362个,潜在铀矿化孔223个.对191号钻孔和36号钻孔进行钻探验证,发现1个工业孔、1个异常孔.认为区内寻找砂岩型铀矿的有利地段为油田区反转构造形成的隆起区边部四方台组河流相砂体,并总结了中央拗陷区南部6种主要控矿因素.     

内蒙古西乌旗罕乌拉地区下二叠统寿山沟组碎屑锆石LA-ICP-MS U-Pb年龄及其地质意义

中亚造山带南缘二叠纪的构造背景一直存在争议。以内蒙古西乌旗罕乌拉地区发育的寿山沟组为研究对象,开展了野外地质、岩石学、碎屑锆石LA-ICP-MS U-Pb年龄研究。2个样品锆石阴极发光图像和Th/U值指示,锆石为岩浆成因锆石。103颗碎屑锆石年龄测试结果显示,年龄信息可划分为5组:285~328Ma,峰期年龄302Ma;338~361Ma;455~490Ma;757Ma;1278Ma、2380Ma。最年轻的年龄为285Ma,结合侵入其中的花岗岩同位素年龄,指示西乌旗罕乌拉地区寿山沟组沉积时限介于285~280Ma之间,主体沉积时代应为早二叠世Sakmarian期—Artinskian期。寿山沟组碎屑锆石反映出近源、快速沉积的特点,沉积物源中含有较多的火山碎屑物,可能代表弧后盆地沉积,为早二叠世古亚洲洋闭合前洋壳俯冲消减作用的沉积响应。结合区域资料,寿山沟组碎屑锆石的年龄对应于东北地区的变质基底及其后的构造岩浆事件,物源区物质主要来自于苏尼特左旗—锡林浩特—西乌旗一带早石炭世末—晚石炭世岩浆弧及贺根山—东乌旗一带,并进一步限制了华北与西伯利亚两大板块的缝合线应位于寿山沟组发育地区的南部,即索伦缝合带,拼合时代最可能为晚二叠世—早三叠世。     

Geologic structure and correlation of the Berriasian-Lower Aptian productive beds of the Gydan Peninsula (Russian Arctic)

We discuss the geologic structure of the Berriasian-Lower Aptian deposits of the Gydan Peninsula. Eight seismic sequences have been distinguished; most of them are associated with Lower Cretaceous regional clinoforms of West Siberia, their characteristics are given. A correlation of productive beds was based on the stratotype sections of the Yamal and Gydan Peninsulas as well as seismic and well data. A sequence stratigraphic model of the Berriasian-Lower Aptian complex is proposed.     

滇中地区因民角砾岩类型、特征及找矿意义

滇中地区“因民角砾岩”的成因及归属问题目前暂无定论。笔者通过对东川-易门地区前人所划的因民组“因民角砾岩”进行1：5万野外地质调查工作,对其进行了初步的分类。根据其成因及时代划分为复成分砾岩、冰碛砾岩、滑塌角砾岩、引爆角砾岩和构造角砾岩。对“因民角砾岩”成因及时代的研究,特别是“冰碛砾岩、复成分砾岩”的提出,对于解决滇中早前寒武纪地层层序、时代归属、构造格架、大地构造位置及大区域地层对比,探讨滇中元古宙地史演化、古环境研究以及指导找矿都具有重要的指示意义。     

朝鲜半岛平南盆地地质演化综述

平南盆地位于朝鲜半岛中部,处于华北克拉通(中朝克拉通)东缘;其演化历史长达10亿年,其地质记录为揭示东亚现今构造格局的形成提供重要制约。盆地发育中元古界-中生界,从下至上包括黄海群(1.3~1.1Ga)、祥原超群(1.0~0.9Ga,自下而上包括直岘群、祠堂隅群、默川群和灭岳山群等)、燕滩群(狗岘系,0.72~0.54Ga)、黄州系/超群(0.52~0.46Ga,包括下部黄州群和上部法洞群)和平安超群(0.33~0.24Ga)等5个构造层序;各单元之间均为平行不整合;沉积跨度超过10亿年,沉积物厚度累计达到15000m。另外,平南盆地南部发育临津群(0.42~0.35Ga),该地层与中元古界上部-奥陶系很可能呈构造接触关系。平南盆地沉积中心自中元古代晚期从南部逐渐向北部转移,新元古代及早古生代均位于中部,二叠纪盆地沉积中心位于北部。平南盆地沉积碎屑锆石年龄则显示物源发生多期变化:中元古代以盆地北侧基底~1.8Ga峰期岩浆-变质作用岩石为主;中元古代晚期以同沉积就位的岩浆岩为主;新元古代以1.6~1.5Ga和1.2~1.1Ga峰期的岩浆岩为主;寒武纪以~2.5Ga和~1.8Ga峰值的变质基底岩石为主。以上变化反映了古地理格局的显著变化。推测新元古代早期及之前,华北克拉通曾与某个发育1.6~1.5Ga和1.2~1.1Ga岩浆作用的克拉通或者岩浆弧相邻(近邻或远邻);地层记录了迄今所知新元古代最早的碳同位素负漂移(默川负漂移,~0.92Ga),地层可能还记录了最晚的负漂移(燕滩负漂移,可能对应全球Gaskiers负漂移,~0.55Ga),它们可能是对新元古代全球长期多次岩浆-裂解-冰期事件的响应。