残留盆地油气系统研究方法——以中国南方中、古生界海相地层为例

通过对南方中、古生界油气地质综合研究及勘探成果总结,初步提出一套改造型残留盆地或叠合盆地的油气系统研究方法,其核心思路是强调进行油气地质的“动态演化”研究,主要通过拟三维盆地模拟反演主要烃源岩的时空演化、生烃过程及其不同地质阶段中的生烃强度、资源量,结合古今油气藏解剖分析油气成藏—破坏规律及古构造分析研究油气运聚指向,结合主要构造运动期对南方中、古生界主要油气系统进行了分阶段的动态演化研究,认为南方中、古生界油气勘探的现实对象是次生油气系统及再生烃油气系统,现存的原生油气系统很少,提出南方中、古生界油气勘探有利区为川东北大巴山前缘及石柱复向斜西侧高陡背斜带、苏北盆地阜宁—盐城—海安—兴化—宝应地区、江汉盆地沉湖地区南部潜江—仙桃—牌州—汊参1井地区、江西南鄱阳盆地及云南楚雄盆地北部凹陷,这一认识已经得到苏北盆地盐城凹陷朱家墩气田及江汉盆地沉湖地区南部开先台西含油构造勘探发现的证实。     

Methods of Studying Petroleum Systems in Residual Basins-A Case Study of Mesozoic and Palaeozoic MarineBasins in Southern China

Through an integrated study of Mesozoic and Palaeozoic petroleum geology in southern China and a summing-up of the results of exploration, the authors tentatively put forward a set of methods of studying petroleum systems in modified residual basins or superposed basins. Its core idea is to put emphasis on the study of the dynamic evolution of petroleum systems. The tempo-spatial evolution, hydrocarbon-generating processes and hydrocarbon-generating intensities and amounts of resources in different geological stages of chief source rocks are mainly deduced backward by 3-D basin modelling. The regularities of formation and destruction of oil and gas accumulations are summarized by analyzing the fossil and existing oil and gas accumulations, the direction of migration is studied by palaeo-structural analysis, and the dynamic evolution of Palaeozoic and Mesozoic petroleum systems in southern China is studied according to stages of major tectonic movements. The authors suggest that the realistic exploration     

Has the plate boundary shifted from central Hokkaido to the eastern part of the Sea of Japan?

A NS trending Cenozoic fold-and-thrust belt has developed in the western part of the Hidaka Collision Zone (HCZ), central Hokkaido, Japan. A quantitative estimation of the late Cenozoic convergence rate at the front of the Hidaka thrust system is important in revealing the plate tectonic framework around northern Japan. High-resolution seismic reflection profiling across the active fault-related folds was carried out to ascertain the temporal change in the crustal shortening rate. Overlapping ramp anticlines and growth folds within thrust sheets were examined using balanced cross-sections combined with industry seismic and drilling data. The rate of shortening was examined using a 3.5 Ma horizon and late Quaternary horizons at 115 and 41 ka. These horizons show that the convergence rate of the Hidaka thrust system has not decreased during the last 3.5 Ma. This suggests that the plate boundary between the Eurasian (Amurian) and North American (Okhotsk) plates has not jumped from the central part of Hokkaido to the eastern part of the Sea of Japan since 3.5 Ma and that a significant amount of plate convergence is still being absorbed in the Hidaka Collision Zone.     

Pseudo 3-D modeling of trishear fault-propagation folding

Basement structures, to which trishear fault-propagation models have most successfully been applied, are commonly three-dimensional folds formed at the tip-line of a fault. We present here a ‘pseudo-3D’ trishear model in which various parameters are permitted to vary along strike and oblique-slip can be modeled. These variations may be combined in an infinite number of ways, facilitating the simulation of many real structures. A thrust changing from blind to emergent can be produced by a change in the slip or propagation-to-slip (P/S) along strike. Folds with forelimbs changing from overturned to upright along strike can be modeled either by changing the slip, P/S or trishear angle. Also some minor folds perpendicular or oblique to the main structure can result from changes in the trishear angle or fault angle along the strike. Models including growth strata show that it is practically impossible to distinguish between growth and pre-growth strata using the map patterns. As a field test, we have modeled the oblique slip East Kaibab monocline, demonstrating a good fit between the field observations and model predictions.     

Polyphase Alpine deformation at the northern edge of the Menderes–Taurus block, North Konya, Central Turkey

Low-grade metamorphic rocks of Paleozoic–Mesozoic age to the north of Konya, consist of two different groups. The Silurian–Lower Permian Sizma Group is composed of reefal complex metacarbonates at the base, and flyschoid metaclastics at the top. Metaigneous rocks of various compositions occur as dykes, sills, and lava flows within this group. The ?Upper Permian–Mesozoic age Ardicli Group unconformably overlies the Sizma Group and is composed of, from bottom to top, coarse metaclastics, a metaclastic–metacarbonate alternation, a thick sequence of metacarbonate, and alternating units of metachert, metacarbonates and metaclastics. Although pre-Alpine overthrusts can be recognized in the Sizma Group, intense Alpine deformation has overprinted and obliterated earlier structures. Both the Sizma and Ardicli Groups were deformed, and metamorphosed during the Alpine orogeny. Within the study area evidence for four phases of deformation and folding is found. The first phase of deformation resulted in the major Ertugrul Syncline, overturned tight to isoclinal and minor folding, and penetrative axial planar cleavage developed during the Alpine crustal shortening at the peak of metamorphism. Depending on rock type, syntectonic crystallization, rotation, and flattening of grains and pressure solution were the main deformation mechanisms. During the F₂-phase, continued crustal shortening produced coaxial Type-3 refolded folds, which can generally be observed in outcrop with associated crenulation cleavage (S₂). Refolding of earlier folds by the noncoaxial F₃-folding event generated Type-2 interference patterns and the major Meydan Synform which is the largest map-scale structure within the study area. Phase 3 structures also include crenulation cleavage (S₃) and conjugate kink folds. Further shortening during phase 4 deformation also resulted in crenulation cleavage and conjugate kink folds. According to thin section observations, phases 2–4 crenulation cleavages are mainly the result of microfolding with pressure solution and mineral growth.     

霍尔果斯活动构造的断裂扩展褶皱作用

作者在论述霍尔果斯活动构造地表特征的基础上,进一步讨论了霍尔果斯活动逆断裂的扩展和背斜褶皱的发育过程。断裂扩展褶皱作用以后断裂构造活动演化为背斜后翼向上分叉的数条南倾的叠瓦状逆断裂,地壳总缩短量在5km以上,缩短率大于5mm/a。     

吉林省印支运动的意义及有关问题的探讨

早印支运动结束了吉林省北部地槽的发展进程,从而南台北槽统一为一体。早印支运动具有华力西构造运动的继承性,晚印文运动时期则具有中生代构造运动的新生性特点。北部地槽是递进式封闭的华力西地槽印支皱褶带。印支运动时期是在亚洲大陆与太平洋构造体系中首次出现大陆边缘活化带的新起点。     

Himalayan structure and metamorphism south of the Main Mantle Thrust, Lower Swat, Pakistan

Abstract During the Eocene-Oligocene, the Indian plate collided with the Kohistan arc along the Main Mantle Thrust (MMT) zone. The structure of the Lower Swat rock sequence, on the Indian plate directly south of the MMT, is a dome with a basement of granitic gneiss and quartz-rich schist unconformably overlain by amphibolitic and calcareous schist. The earliest superposed small-scale folds (F1 & F2) represent a progressive F1/F2 deformation that is associated with a single set of WSW-vergent large-scale folds (termed F2). These folds are inferred to have developed during oblique, WSW-directed overthrusting of the MMT suture complex onto the Lower Swat rock sequence. Metamorphism began during F1/F2 as indicated by an S1 foliation that developed during biotite-grade metamorphism. S1 is preserved as a relict texture in porphyroblasts that grew during a subsequent interkinematic phase during garnet- and higher grade metamorphism. The dominant, regional foliation (S2) developed following the interkinematic phase. S2 is associated with transposition of S1 and rotation or dismemberment of porphyroblasts. Annealing recrystallization followed S2 and continued during F3 thereby destroying or masking possible pre-existing stretching fabrics. Superposed F3 folds are upright and open with N-S axial trends. They may correlate with early doming of the Lower Swat rock sequence and with strike-slip displacement in the northern part of the MMT zone, north of the Lower Swat area. F3 was followed by retrograde metamorphism and development of E-W-trending, S-vergent F4 folds. F4 may be associated with a final phase of southward directed thrusting and inactivity in the MMT zone. Correlation of published ⁴⁰Ar/³⁹Ar ages with the metamorphic fabrics suggests that F1/F2 and F3 occurred in the Eocene, and that F4 developed in the Oligocene. F4 is the earliest indication of southward verging structures on this part of the Indian plate.