关于松辽盆地内部地体碰撞的探讨

通过对地震资料中特殊现象的解释提出了松辽盆地内部东西地体碰撞的看法,合理地解释了松辽盆地滨北地区地质现象的形成机制,并且认为地体碰撞带可能是无机生油的有利场所。     

Spectral characterization and ASTER-based lithological mapping of an ophiolite complex: A case study from Neyriz ophiolite, SW Iran

The Neyriz ophiolite occurs along the Zagros suture zone in SW Iran, and is part of a 3000-km obduction belt thrusting over the edge of the Arabian continent during the late Cretaceous. This complex typically consists of altered dunites and peridotites, layered and massive gabbros, sheeted dykes and pillow lavas, and a thick sequence of radiolarites. Reflectance and emittance spectra of Neyriz ophiolite rock samples were measured in the laboratory and their spectra were used as endmembers in a spectral feature fitting (SFF) algorithm. Laboratory spectral reflectance measurements of field samples showed that in the visible through shortwave infrared (VNIR-SWIR) wavelength region the ultramafic and gabbroic rocks are characterized by ferrous-iron and Fe, MgOH spectral features, and the pillow lavas and radiolarites are characterized by spectral features of ferric-iron and AlOH. The laboratory spectral emittance spectra also revealed a wide wavelength range of SiO spectral features for the ophiolite rock units. After continuum removal of the spectra, the SFF classification method was applied to the VNIR + SWIR 9-band stack, and to the 11-band data set of SWIR and TIR data sets of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor, using field spectra as training sets for evaluating the potential of these data sets in discriminating ophiolite rock units. Output results were compared with the geological map of the area and field observations, and were assessed by the use of confusion matrices. The assessment showed, in terms of kappa coefficient, that the SFF classification method with continuum removal applied to the SWIR data achieved excellent results, which were distinctively better than those obtained using VNIR + SWIR data and TIR data alone.     

班公错—怒江缝合带西段纳屋错蛇绿岩特征

通过对纳屋错地区蛇绿岩的地质背景、岩石学、地球化学特征及构造环境分析,发现超基性岩以高Cr、Ni、Co、稀土总量,低Mg'值为特征,主量元素及稀土元素特征表明其与蚀变玄武岩具有同源岩浆的特点。蚀变玄武岩的主量元素显示其具有拉斑玄武岩向碱性玄武岩过渡的特征;微量元素结果分析表明它与典型大洋中脊玄武岩明显不同,分配型式近似平坦型,相对富集大离子亲石元素Rb、Ba、Sr和高场强元素Th、Ta、Hf,但Nb亏损;在稀土元素配分模式中为轻稀土富集的向右缓倾型式,无明显的Eu异常,但负Ce异常,与洋岛碱性玄武岩的特征相似。根据蛇绿岩的地球化学特征并应用构造环境判别图解,确定该地区蛇绿岩形成于洋脊扩张环境,但不是典型的大洋型蛇绿岩,类似于边缘海型蛇绿岩。     

塔里木盆地西部及邻区板块构造属性与区划

根据蛇绿岩带分持征及配套系的研究，在研究区内划分出了五条蛇绿岩带。以塔里木北缘蛇绿岩带为界将塔里木陆块与哈萨克斯坦板分开；以多期俯冲形成的康西瓦蛇绿岩带将塔里木陆块与高加索－羌塘板块分开。     

东秦岭松树沟蛇绿岩区的构造样式

松树沟蛇绿岩产于东秦岭碰撞缝合带，对该地区详细的地质填图表明其构造基本样式为一系列不同尺度的线状强剪切变形带与透镜状弱变形域在空间上有规律的交织组合。     

新疆库地地区蛇绿岩含金性研究

新疆库地蛇绿岩堆积厚度达１ ５００ ｍ 以上,主要岩石由纯橄岩、斜辉橄榄岩、辉长岩、块状玄武岩、枕状玄武岩、玄武安山岩、硅质岩、粉砂岩等组成。岩石化学和稀土元素分析表明蛇绿岩形成于洋盆环境,通过微量元素分析,金的背景值高（２０ ×１０ － ９） ,Ａｕ 与Ｃｕ 、Ｍｇ、ＴＦｅ 正相关,与Ｋ２Ｏ、Ｓｒ 负相关,探讨了该蛇绿岩带的含矿（ 金） 性及可能形成的金矿类型     

Mantle metasomatism for metaperidotite from Shuanggou ophiolite of Yunnan Province by proton microprobe

This study shows that olivine,serpentine and orthopyroxene are enriched with compatible element Ni;clinopyroxene with Ni and Y;spinel strongly with Ni,Zn,Ga,Ge,As and Zr;chlorite with Ni,Zn,Sr and Zr,However,grossulatrite is poor in all of these trace elements,except Sr.The trace element composition and distribution in the minearls are heterogeneous.The distributions of trace elements in the minerals further demonstrate that they result from mantle metasomatism under open system.     

准噶尔盆地东北缘卡拉麦里构造带盆内延伸方式及其对盆地基底性质的影响

卡拉麦里构造带位于准噶尔盆地东北缘,对于其向盆内延伸的方向、与盆地内构造带的关系等问题目前认识仍不明确,制约了对该盆地基底性质以及盆内石炭系火山岩储层大地构造属性的认识。为此,对该盆地东部白碱沟地区石炭系巴塔玛依内山组火山沉积地层进行了地质填图及SHRIMP锆石U-Pb原位定年,结合前人的研究成果,从火山机构与火山岩分布、火山活动时限等方面,对比了盆内及卡拉麦里构造带石炭系火山岩的地质特征,探讨了该构造带在盆内的延伸方式及其影响。结果表明:①白碱沟地区巴塔玛依内山组出露的流纹岩其SHRIMP锆石U-Pb定年结果为距今300.8±4.9 Ma,表明该区火山活动时间为晚石炭世晚期;②陆梁隆起与卡拉麦里构造带属同一条构造单元,其基底原型为一套增生型造山带;③陆梁隆起发育的2条SEENWW向中基性火山岩带是野马泉岩浆弧和哈尔里克岩浆弧在盆内的延伸,2条火山岩带之间为卡拉麦里蛇绿岩带;④陆东—五彩湾地区石炭系火山岩储层发育在南侧火山岩带中,其形成的大地构造环境为岛弧环境。     

超镁铁岩的REE特点及其对青海德尔尼铜钴矿的成因意义

不同成因的超镁铁岩具有不同的ＲＥＥ特点。与硫化镍矿有关的侵入超镁铁岩有较高的ＲＥＥ含量，富集轻稀土；蛇绿岩套中的变质橄榄岩ＲＥＥ含量较低，以“Ｕ”型或轻稀土亏损型为特点。德尔尼超镁铁岩体有变质橄榄岩的ＲＥＥ特征，属蛇绿岩套的一部分，为地幔物质低度部分熔融的产物，部分熔融程度约为５％。德尔尼铜矿属火山成因的块状硫化物矿床，由于构造作用致使矿体产于超镁铁岩中。阿尼玛卿山地区铜钴矿的找矿方向是原布青山群和部分三叠系中玄武岩－硅质（碳质）板岩出露地区。     

CRETACEOUS – NEOGENE STRUCTURAL EVOLUTION OF SE ABU DHABI,UNITED ARAB EMIRATES

Regional 2D seismic profiles and 2D cross‐sections extracted from high‐resolution 3D seismic data were interpreted together with well data to reconstruct the sequence stratigraphy of the Late Cretaceous – Miocene sedimentary succession in SE Abu Dhabi. This region is a major hydrocarbon province with numerous giant oilfields producing from large‐scale anticlines. The paper focusses on the structural development of the Sahil, Asab and Shah fields. Six sequence boundaries within the Aptian to Miocene succession were identified on the basis of erosional truncations and onlap patterns. The deepest‐lying erosional surface is the top‐Albian sequence boundary. This was identified by angular truncation of the Nahr Umr Formation in the SE of the study area near an uplifted domal structure which hosts the Mender and nearby Lekhwair fields. The unconformity is interpreted to result from reactivation of the basement together with a eustatic fall in sea‐level which resulted in regional uplift and erosion. A second phase of uplift occurred during the mid‐Turonian and resulted in significant erosion of the Shilaif Formation along structural highs. The top‐ Shilaif Formation unconformity forms a sequence boundary and is observed at the Shah, Zararrah and Sahil anticlines. The unconformity is coeval with the onset of obduction of the Semail Ophiolite onto the Arabian margin, and the associated flexural bulge probably resulted in structural uplift and reactivation of basement structures. A global sea‐level fall is also reported during middle Turonian time. The third sequence boundary occurs in the lower Campanian as an angular unconformity surface between the Halul and Fiqa Formations. This event is most obvious along the Shah and Zararrah anticlines and is interpreted to have occurred as a result of flexural uplift related to a further episode of obduction of the Semail Ophiolite. The fourth sequence boundary occurs in the Campanian – Maastrichtian and was identified by angular truncations of the Fiqa Formation against the Simsima Formation, an event which caused widespread erosion of a significant portion of the Fiqa Formation. This tectonic activity was most likely controlled by the final emplacement of the Semail Ophiolite, and probable reactivation of basement faults. The Simsima Formation is bounded above by the fifth sequence boundary, which coincides with the Cretaceous/Tertiary boundary and which is associated with the final stages of Late Cretaceous tectonic activity. The final sequence boundary is the supra‐Dammam unconformity, which resulted in a peneplain surface associated with widespread erosion and an extended hiatus. Major trap formation in the study area occurred from the Cenomanian to the Maastrichtian, and coincided with obduction‐related emplacement of allochthonous thrust sheets onto the plate margin in Oman. However, the structural growth history of the Shah, Asab and Sahil anticlines suggest multiple episodes of uplift. Growth of the Shah anticline was initiated during deposition of the Shilaif Formation in Cenomanian – early Turonian times, but neither the Asab nor Sahil anticlines show significant growth or faulting older than Campanian. In all the anticlines, the most pronounced tectonic activity observed was in the Campanian during deposition of the Fiqa Formation. Significant growth of structures was completed by Paleocene time, suggesting that the Zagros orogeny had little structural influence in SE Abu Dhabi.