中国东、南部大陆、海域与邻区(国)古构造演化关系

本文论证了中国海域基底与邻区古构造演化关系,中朝地台与京畿地块以北对应。中下扬子台拗东延为朝南古拗陷,东南地槽系连接本州地槽系,华夏地块经东海接日本“南方大陆”,华夏和印支地块隶属于南海—东海地台的边缘地块。     

Why are halo coronal mass ejections faster?

Halo coronal mass ejections (CMEs) have been to be significantly faster than normal CMEs, which is a long-standing puzzle. In order to solve the puzzle, we first investigate the observed properties of 31 limb CMEs that clearly display loopshaped frontal loops. The observational results show a strong tendency that slower CMEs are weaker in white-light intensity. Then, we perform a Monte Carlo simulation of 20000 artificial limb CMEs that have an average velocity of ～523km s -1. The Thomson scattering of thes...     

Do protostellar fountains shape the regional core mass function?

The emerging massive binary system associated with AFGL 961 signifies the latest generation of massive star and cluster formation in the Rosette Molecular Complex. We present the detection of a compact cluster of dusty cores toward the AFGL 961 region based on continuum imaging at 1.3 mm by the Submillimeter Array. The binary components of AFGL 961 are associated with the most intensive millimeter emission cores or envelopes, confirming that they are indeed in an early stage of evolution. The other massive cores, however, are found to congregate in the close vicinity of the central high-mass protostellar binary. They have no apparent infrared counterparts and are, in particular, well aligned transverse to the bipolar molecular outflows originating from AFGL 961. This provides evidence for a likely triggered origin of the massive cores. All 40 individual cores with masses ranging between 0.6 and 15 M⊙ were detected above a 3 σ level of 3.6 mJy beam-1 (or0.4 M⊙ ), based on which we derive a total core mass of 107 M⊙ in the AFGL 961 region. As compared to the stellar initial mass function, a shallow slope of 1.8 is, however, derived from the best fit to the mass spectrum of the millimeter cores with a prestellar and/or protostellar origin. The flatter core mass distribution in the AFGL 961 region is attributed here to dynamic perturbations from the massive molecular outflows that originated from the massive protostellar binary, which may have altered the otherwise more quiescent conditions of core or star formation, enhanced the formation of more massive cores and, as a result, influenced the core mass distribution in its close vicinity.     

东濮凹陷杜寨地区深层砂岩储层致密化与油气充注关系

为分析东濮凹陷杜寨地区沙三中—下亚段致密砂岩储层演化与油气充注过程的耦合关系,综合运用铸体薄片、阴极发光、扫描电镜、荧光显微及流体包裹体等测试方法,明确杜寨地区沙三中—下亚段储层特征、成岩作用、成岩演化序列、储层孔隙度演化史和油气充注史等。结果表明:杜寨地区沙三中—下亚段处于中成岩B期至晚成岩阶段,在经历三期钙质胶结、三期溶蚀、持续压实的复杂成岩过程后,在斜坡带发育低孔低渗砂岩储层,在洼陷带发育特低孔特低渗致密砂岩储层。东营组沉积末期,储层尚未致密化,低熟—成熟有机质在斜坡带聚集形成常规型油气藏,在洼陷带附近形成"边致密边成藏"型致密砂岩油气藏。明化镇组沉积末期至今,储层致密,除少量油气向上运移、在斜坡带形成"边致密边成藏"型油气藏外,仍有大量晚期生成的天然气在洼陷带附近聚集,形成典型的"先致密后成藏"型致密砂岩气藏。     

鄂西地区深层页岩气储层岩相孔隙结构特征差异及其控制因素——以YT1和YT3井五峰—龙马溪组页岩为例

岩相页岩孔隙结构是影响页岩气储集及运移能力的重要因素。以鄂西地区五峰—龙马溪组深层页岩为例,采用小角中子散射、高压压汞和场发射扫描电镜等实验方法,对比不同岩相页岩孔隙结构特征,明确不同岩相页岩孔隙结构特征差异及其控制因素。结果表明：鄂西地区五峰—龙马溪组页岩划分为高有机质硅质页岩岩相、中有机质硅质页岩岩相和低有机质黏土/混合质页岩岩相,不同岩相总孔隙度为1.76%～4.27%;高有机质硅质页岩和中有机质硅质页岩储集空间以有机孔为主,低有机质黏土/混合质页岩储集空间以无机孔为主,微裂缝发育程度为高有机质硅质页岩>中有机质硅质页岩>低有机质黏土/混合质页岩;有机质丰度和矿物组分是不同岩相页岩孔隙结构差异主控因素,随总有机碳质量分数和硅质矿物质量分数降低,有机孔密度和孔径显著下降,孔隙结构非均质性减弱,微裂缝发育程度逐渐降低。高有机质硅质页岩相具有较强生烃潜力,微裂缝发育程度较高,为研究区段最优页岩相。总有机碳质量分数和矿物组分是五峰—龙马溪组深层页岩气储层不同岩相孔隙结构特征差异关键因素,高有机质硅质页岩相为研究区段最优页岩相。该结果为鄂西地区下寒武统五峰—龙马溪组深层页岩气储...     

深反射地震成像揭示的班公湖 怒江缝合带中段Moho断阶及其大地构造意义

揭示班公湖- 怒江(班怒)缝合带Moho(莫霍面)结构对于认识中特提斯洋壳俯冲和南羌塘坳陷成因具有重要地球动力学意义。基于横跨班怒缝合带的深反射地震数据(88°30′E),本文采用了中长波长静校正、噪声压制、优化叠加和叠前深度偏移(PSDM)等地震处理技术,获得了深度域地震反射偏移剖面、层速度场和高分辨率Moho结构。由深度域剖面显示,班怒缝合带Moho位于地表以下65～80 km,呈不连续北向抬升趋势,指示在拉萨地块与南羌塘地块之间存在岩石圈上地幔断阶,最大阶步可达15 km。综合分析缝合带两侧的Moho形态认为,这些断阶受南侧拉萨地体的岩石圈上地幔以19. 5°北倾俯冲与北侧南羌塘地块的上地壳抬升驱动,可能与深部存在局部熔融相关。班怒缝合带下的Moho结构表明,随着晚侏罗世—早白垩世中特提斯洋闭合,南羌塘地体由边缘海沉积向前陆盆地转换,形成南羌塘坳陷。     

新疆大红柳滩伟晶岩型锂矿深部结构与区域成矿模型解释

为揭示花岗岩- 伟晶岩型锂等稀有金属矿成矿系统的深部结构,对西昆仑造山带大红柳滩伟晶岩型锂矿集区开展了大地电磁测深法(MT)探测。通过MT三维反演电阻率模型,探测到两个0~20 km深度范围的高阻体,反映了出露于地表的大红柳滩复式花岗岩基和半隐伏的大红柳滩东花岗岩基;20~80 km深度范围内发现的大范围高导异常,则反映了深达上地幔的地壳重熔形成的大规模长英质岩浆储库。可见,成矿母岩大红柳滩花岗岩基是有根的,而且是规模巨大深达上地幔的岩浆储库,它们为超大型大红柳滩伟晶岩型锂矿的形成提供了物源和热源。与松潘- 甘孜甲基卡超大型伟晶岩型锂矿集区对比,尽管川西甲基卡地区地表出露的花岗岩有限,但MT三维反演电阻率模型显示,其也存在深达上地幔的大范围高导异常,同样反映了大规模长英质岩浆储库的存在,只是剥蚀深度浅,上侵的花岗岩未被剥蚀出来而已。从而,深剥蚀的大红柳滩地区表现为大面积花岗岩出露的“热隆”特征,而浅剥蚀的甲基卡地区则表现为花岗岩围岩“片麻岩穹隆”热变质构造特征。西昆仑- 松潘- 甘孜伟晶岩型锂等稀有金属巨型成矿带两端的晚三叠世超大型矿床是大规模地壳重熔长英质岩浆作用中心的产物,由于锂等稀有金属的喜水性,H2O的饱和度是造就伟晶岩型锂超常富集的关键,并在长英质岩浆储库、上侵花岗岩和伟晶岩不同分异演化阶段,锂的“预富集”为大规模伟晶岩型锂矿成矿奠定了重要基础。     

河南省渑池县贾家洼西段铝土矿地质特征

通过大量的地质勘查工作及综合研究,认为本区铝土矿具有埋藏浅、规模大、易开采、易加工的特征,属沉积型铝土矿,是我省大型铝土矿床之一。