Using Models of the Deep Structure of the Earth’s Crust and Upper Mantle Based on GOCE Gravity Data in Metallogenic Analysis

Izvestiya, Atmospheric and Oceanic Physics - Gravimetric data obtained by the GOCE spacecraft contributes to the development of global models of the deep structure of the Earth’s crust and...     

黑龙江东部依兰珠山变辉长岩的年代学、地球化学及其构造意义

对黑龙江东部依兰珠山变辉长岩进行了锆石年代学和地球化学研究,以确定其形成时代、成因及构造背景。变辉长岩锆石均呈自形-半自形晶,具典型的条痕状吸收特征和较高的Th/U比值(0.20~0.86),暗示其岩浆成因。LA-ICP-MS U-Pb测年结果为(256±3)Ma,表明珠山变辉长岩形成于晚二叠世。地球化学特征显示变辉长岩具有贫硅,富镁、铁、铝、钙的特征;其轻稀土元素(LREEs)和大离子亲石元素(Rb、Ba)富集,重稀土元素(HREEs)和高场强元素(Nb、Ta、Zr、Hf和Ti)亏损。结合区域地质资料,认为珠山变辉长岩为俯冲流体交代地幔楔的产物,其形成可能与古大洋板块的俯冲作用有关,暗示佳木斯地块与松嫩地块在晚二叠世之前尚未碰撞拼合。     

Geodynamic setting,structure, and composition of continuous trachybasalt-trachyandesite-rhyolite series in the north of Altai-Sayan area: the role of crust-mantle interaction in continental magma formation

The geologic positions and geochemical and isotope parameters of the Ordovician-early Silurian and Early-Middle Devonian continuous volcanic series of the Minusa basin and its mountainous framing are compared. Both series are composed mostly of moderately alkaline rocks with variations in SiO₂ contents from 45 to 77 wt.%. The Ordovician-early Silurian series differs from the Early-Middle Devonian one in lower contents of TiO₂ (< 1.7 wt.%) and Fe₂O_3tot and higher contents of Al₂O₃ in all rock varieties and in the more fractionated REE patterns of trachybasalts. The compositions of both series reflect two simultaneous mechanisms of magma evolution. The main process was fractional crystallization leading to the formation of rocks from trachybasalts to trachyrhyodacites. The accessory mechanism was the contamination of fractionated melts by crustal material, anatectic melting of crust, and mixing of deep-seated magmas with crustal melts. These processes had specifics at each stage and were controlled by the composition of the sources of parental melts. Their geochemical and isotopic parameters (high alkalinity, high contents of lithophile elements, negative anomalies of Nb, Ta, and Ti, and enrichment in radiogenic Sr) point to the interaction of mantle plumes with the lithospheric mantle that was metasomatically transformed during the preceding Vendian-early Cambrian subduction processes.     

Lateral extrusion along the Altyn Tagh Fault,Qilian Shan (NE Tibet): insight from a 3D crustal budget

The lithospheric strike‐slip Altyn Tagh Fault has accommodated hundreds of kilometres of displacement between the Qaidam and Tarim blocks since its Eocene reactivation. However, the way the deformation is accommodated in the Qilian Shan and further east remains uncertain. Based on 360 km of north‐eastward migration of the relatively rigid Qaidam block along the Altyn Tagh Fault and 3D isovolumetric balancing of the crustal deformation within the Altyn Tagh Fault–Qilian Shan system, we demonstrate that 250 ± 28 km (43.8–49.4%) of N20E directed crustal shortening and an additional ~250–370 km of eastward motion of the Qilian Shan crust must be accounted for by strike‐slip faulting in the Qilian Shan and crustal thickening in the Qinling area, as well as by extension in the adjoining North China block graben systems.     

季节偏差纠正下的遥感AOD产品降尺度BGIM算法

MODIS 3 km DT (Dark Target)卫星气溶胶光学厚度AOD (Aerosol Optical Depth)数据产品已广泛应用于大气污染监测,但受反演方法限制,该数据产品像元缺失严重、时空覆盖度低、精度偏低。相比,MODIS 10 km DT＿DB＿Combined AOD数据产品因融合DT和DB (Deep Blue)两种反演算法,一定程度上可弥补MODIS 3 km DT AOD数据产品在时空覆盖度与精度方面的缺陷,但分辨率偏低。此外,受气溶胶组分来源的季节变化与地表反射率估算的季节性误差影响,MODIS AOD数据产品精度同时也存在季节性特征。本文由此以京津冀为试验区,顾及AOD季节变化特性,开展MODIS 10 km DT＿DB＿Combined AOD数据产品偏差纠正下的地统计反演模拟BGIM(Bias-corrected Geostatistical Inverse Model)降尺度算法研究。试验同时引入AERONET地基观测数据和MODIS3 km DT AOD数据产品作为降尺度结果的绝对与相对验证标准。结果表明：季节偏差系数纠正下生成的MODIS3 ...     

Study of Influence of Regional Geodynamic Background on Strata Behaviors in China's Tongxin Mine

Strata behaviors are mainly affected by regional geodynamic background. The influence of rock mass stress and energy distribution on strata behaviors in the Tongxin mine is studied in terms of regional tectonic movement, seismic activity and tectonic stress field. The results show that the extrusion lifting movement of Kouquan fault adjacent to the Tongxin mine results in the stress concentration in the rock of the Carboniferous coal bed and accumulation of a large amount of elastic energy and forms structural background of Tongxin mine. Due to various seismic activities in the mine area, the strain energy is known to reach much higher levels, up to 0.5×10⁸ J^1/2. Since the stratigraphic structure is sensitive to the mining operation, the strain energy could cause strong strata behaviors. A special geological structure model of the Tongxin mine is established based on the geodynamic division method. The distribution of regional structure stress field is determined by the rock mass stress analysis system. Based on this model, Tongxin mine is divided into five areas with high stress, eight areas with low stress and eight areas with gradient stress. The strong strata behaviors mostly occur in high stress areas. These results could provide guidance to predict the strength of regional or mine pressure and control strata behavior in different areas.     

Subpollen Particles as Atmospheric Cloud Condensation Nuclei

Izvestiya, Atmospheric and Oceanic Physics - Bioparticles constitute a significant fraction of atmospheric aerosol. Their size range varies from nanometers (macromolecules) to hundreds of...     

页岩气资源量计算：以鄂尔多斯盆地中生界三叠系延长组长7为例

鄂尔多斯盆地三叠系延长组长7暗色泥页岩是重要的烃源岩。最近的勘探表明,长7具有良好的页岩气开发前景。重点利用鄂尔多斯盆地279口测井资料、18口取心井的347块岩样实验室多种分析测试资料,开展了鄂尔多斯盆地中生界延长组长7页岩气的岩性、岩相、孔隙类型、有机碳含量、热演化程度、含气性、气体储存方式及其在测井曲线的反响研究;在页岩气形成条件的研究基础上,建立了岩性、含气性、有机质含量与自然伽马、声波时差、电阻率之间的关系,有效地识别含气泥页岩;选择容积法对延长组页岩气资源量进行计算,为未来页岩气的勘探和开发奠定基础。     

江西利山金矿床地质特征及控矿构造

本文较系统地阐述了利山金矿床的各项地质特征，并重点就控矿构造问题进行了总结讨论，认为ＮＷＷ向断裂带严格控制了所有金矿体的产出。ＮＮＥ、ＮＮＷ向断裂与ＮＷＷ向断裂带的交汇部位控制了富矿段的产出。在此基础上初步探讨了矿床成因及找矿方向，这对该地区的找矿评价和开发均具有实际意义