冲断构造带深层变形的空间分布规律——以库车坳陷克拉苏构造带为例

传统上认为前陆冲断带内部的背斜构造具有"成排成带分段"的特征,在表观认识和宏观尺度上讲,容易理解这一特征,并且通过"成排成带分段"的解剖,直接为含油气区带评价和地震解释方案的落实提供指导作用。随着前陆冲断带深层结构的精细解剖和三维空间内构造变形的准确刻画,发现前陆冲断带深层构造变形的分布并非成排成带分段的特征,褶皱构造的发育与分布明显受前陆冲断构造位移量及各个断层位移量的大小所控制,各个断层控制的逆冲岩席在垂向上相互叠置、侧向上交叉对接、走向上错落有致, 3D立体空间内由多个次级弧形体组成鳞片状分布。本文以中国天然气勘探最为成功、勘探资料最为详实的库车坳陷克拉苏构造带为例,通过地震剖面精细构造解释,揭示出构造变形的运动学特征及其构造位移量在传播过程中的分异和转换,进而控制冲断带内部构造岩席的生长发育和空间展布特征,并在3D立体空间内揭示冲断岩席受构造位移量的控制而成鳞片状分布的规律,控制这一分布规律的主控因素是冲断构造位移量与冲断岩席长度之间定量的几何关系。这一认识提升了油气藏评价和构造圈闭描述的精度。     

造山带与前陆盆地结构构造及动力学研究思路和进展

运用大量的研究成果，综合分析了大陆岩石圈结构和动力学特征，在此基础上探讨了造山带研究的思路和方法，总结了造山带结构、构造及其形成演化研究的新进展。指出前陆盆地的研究是深入研究造山带的关键，前陆盆地是前陆冲断作用引起岩石圈挠曲变形的结果，阐述了前陆盆地形成机制的研究进展     

Transitional environments of the lower Maastrichtian South-Pyrenean Basin (Catalonia,Spain): The Fumanya Member tidal flat

Sedimentological, palaeontological and geochemical data provide detailed evidence of a marine-to-lagoon environmental succession around the Campanian-Maastrichtian boundary in the Ibero-Armorican domain. This regression is recorded by the succession of several environments of the south-central Pyrenees basin: open marine mixed shelf, marine restricted mixed shelf (both rudist-rich), tidal flat, lagoon and fluvial dominated. The tidal flat setting belongs to the Fumanya Member here described, which is the base of the Posa and Massana formations (Tremp Group). The Fumanya Member is 5 m thick, is built up of marly limestones and was an elongated tidal mudflat (100 km long, 25 km wide) developed in a foreland trough and was separated from the Atlantic Ocean by an island-barrier system. In the lagoon environment, marginal marine waters and continental fresh waters alternated as documented by geochemistry and fossil molluscs. The Fumanya Member is a dinosaur megatracksite, reporting the roaming activity only of sauropods in tidal flats, a likely secure area against predators. Feeding activity of these herbivores took place in the lagoonal-lacustrine environments of the Posa Formation above the Fumanya Member.     

Diagenesis of the Paleogene Sandstones in the DN2 Gas Field,Kuqa Foreland Basin and its Link to Tectonics

We investigated diagenesis of the sandstones from the DN2 Gas Field of the Kuqa Foreland Basin(KFB),in order to infer the timing of fluid migration and discuss the linkage between fluids and tectonics.The textures and chemical composition of authigenic minerals,fluid evidence from fluid inclusions and formation water measurements were all used to fulfill this aim.Eodiagenesis occurred with the participation of meteoric water and connate water.Mesodiagenesis is related to high salinity fluids,whi...     

Genesis of the Late Archean granitoids of the northern part of the Dharwar foreland (Dharwar Craton), south India – Insights from field,crystal size distribution,thermobarometry, microgeochemical and bulk-rock geochemical studies

An intrusive granitoid pluton into TTG-Dharwar Supergroup greenstone sequence is being reported for the first time from the Dharwar Foreland region. Based on field and petrographic characteristics, these granitoids are classified as - quartz-monzodiorites and granites. Occasional mafic bodies of dioritic-granodioritic composition with size ranging from small microgranular magmatic enclaves to bodies of several centimeters are common in these granitoids.The granitoids are devoid of any crystal-plastic fabric as well as high-strain characteristics. The textural (CSD) studies indicate that the quartz-monzodiorites are derived from magma mixing whereas the granites are derived from equilibrium crystallization of the magma derived from the reworking of quartz-monzodiorites. The P-T estimates indicate that the quartz-monzodiorites were crystallized at higher temperature (>950 °C) and pressure (3.09–4.36 kbar) conditions in a reducing environment at mid-crustal levels. However, the granites indicate lower temperature (<750 °C) and pressure (0.89–1.88 kbar) conditions of crystallization in an oxidizing environment at shallow-crustal levels. The bulk rock chemical characteristics indicate that the quartz-monzodiorites were derived from the melt generated by the mixing of two melts - a melt derived from the differentiation of sanukitoids senso lato (s.l.) and a melt derived from the partial melting of TTG. On the other hand, reworking of the hot crystallizing quartz-monzodiorite due to its rapid upliftment to shallow crustal levels resulted in a decompression melting which gave rise to granitic melts.The relative age of the Dharwad granitoids is estimated to be ∼2580–2560 Ma and unlike the other older granitoids (> 2.61 Ga) reported from the northern part of the Shimoga greenstone belt, the studied granitoids marks the final stage of cratonization in the Foreland region.     

广西十万大山盆地构造特征新认识

 通过对横穿十万大山前陆盆地的SD94-Ⅳ地震剖面的解释,证实十万大山盆地曾经历了至少2次以上的不同方向的构造运动:早期为前泥盆纪,表现为北西向南东的冲断;晚期为中泥盆世至白垩纪,构造由南东向北西发展.该地区在加里东期存在的北西向南东方向的构造运动值得进一步研究.     

关于库车巴什基奇克组时代的讨论

根据近年来对新疆库车前陆盆地及北部坳陷中生代主要储气层巴什基奇克组介形类、轮藻和孢粉化石的研究 ,认为该组主体的地质时代应为早白垩世中期。     

Combined tectonic-sediment supply-driven cycles in a Lower Carboniferous deep-marine foreland basin,Moravice Formation,Czech Republic

The Lower Carboniferous Moravian–Silesian Culm Basin (MSCB) represents the easternmost part of the Rhenohercynian system of collision-related, deep-water foreland basins (Culm facies). The Upper Viséan Moravice Formation (MF) of the MSCB shows a distinct cyclic stratigraphic arrangement. Two major asymmetric megacycles bounded by basal sequence boundary, each about 500 to 900 m thick, have been revealed. The megacycles start with 50- to 250-m-thick, basal segments of erosive channels: overbank successions and slope apron deposits interpreted as lowstand turbidite systems. Up-section they pass into hundred metre-thick, fine-grained, low-efficiency turbidite systems. Palaeocurrent data show two prominent directions, basin axis-parallel, SSW–NNE directions, which are abundant in the whole MF, and basin axis-perpendicular to oblique, W–E to NW–SE directions, which tend to be confined to the basal parts of the megacycles or channel-lobe transition systems in their upper parts. Based on the facies characteristics, palaeocurrent data, sandstone composition data and trace-fossil distribution data, we suggest a combined tectonics–sediment supply-driven model for the MF basin fill. Periods of increased tectonic activity resulted in slope oversteepening probably combined with increased rate of lateral W–E sediment supply into the basin, producing the basal sequence boundary and the subsequent lowstand turbidite systems. During subsequent periods of tectonic quiescence, the system was filled mainly from a distant southern point source, producing the thick, low efficiency turbidite systems. Consistently with the previous models, our own sediment composition data indicate a progressively increasing sediment input from high-grade metamorphic and magmatic sources up-section, most probably related to an uplift in the source area and progressive unroofing of its structurally deeper crustal parts. The first occurrence of the Cruziana–Nereites ichnofacies in sand-rich turbidite systems in the youngest parts of the MF (Goel to Gospi Zone), supported by rapidly increasing quartz concentrations in sandstones, is thought to indicate a transition from generally underfilled to generally overfilled phase in evolution of the MSCB basin. This transition may be linked to the onset of Upper Viséan phase of northward basin-fill progradation assumed by previous authors.