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A chronological study of seamount rocks in the South China Sea basin provides a great opportunity to understand the expansion and evolution history of the sea basin. In this paper, we analyzed the 40Ar... 相似文献
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本文基于谱元法,模拟三种深度的点震源下,四种倾角的三维单一小盆地模型和盆地－子盆地模型的地震动,通过盆地模型和基岩半空间模型的傅氏谱比分析三维盆地－子盆地模型的共振频率和放大特性。结果表明:（1）盆地－子盆地模型下,外部大盆地的存在导致子盆地共振频率下降约5%,盆地倾角的增大导致子盆地的共振频率略微减小。三维子盆地的共振频率约为二维模型的1.5倍左右。（2）子盆地模型相对于基岩半空间的放大倍数随着盆地形状比降低而增加。形状比由0.88降低至0.5,子盆地的放大系数增大1.3－1.8倍左右。（3）盆地－子盆地模型相对于单一小盆地模型的放大随震源深度的增加而降低,震源深度由2 km增加到18 km,由2.3降至1.3。 相似文献
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LI Shengli YU Xinghe ZHANG Feng LIANG Xingru LI Shunli HUANG Jie CAO Nanzhu 《《地质学报》英文版》2017,91(6):2255-2267
The Baxian depression is a typical half-graben located in the Jizhong sub-basin, north China. Commercial petroleum traps have been discovered in the Jizhong sub-basin. However, the 3rd and 4th members of the Shahejie Formation in this sub-basin have been poorly explored. These two members, belonging to the Lower Paleogene age, are buried deeply in the depression. Favorable petroleum reservoir conditions exist in such deep intervals of the half-graben due to the presence of different types and extent of deltas and turbidity fans in various areas. In fact, three types of turbidite fans are developed in the sag below the transitional belt on the eastern gentle slope. This work summarized three stratigraphic trap belts, i.e., the steep slope, gentle slope, and sag. On the steep slope, structural-stratigraphic traps with small-scale delta fronts and turbidite sandbodies are well developed. On the gentle slope, hydrocarbons generally accumulate in the large-scale delta front, onlapping beds and those sandbodies adjacent to unconformities. In the sag, petroleum trap models are typically characterized by pinched-out turbidite sandbodies. Stratigraphic traps were easily formed in turbidite fans below the eastern transitional belt. The petroleum traps that have already been discovered or predicted in the study area indicate that stratigraphic traps have favorable petroleum exploration potential in deeply buried areas (depth >5000 m) in a half-graben basin or depression. 相似文献
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Claudio Corrado Lucente 《Sedimentary Geology》2004,170(3-4):107-134
The Marnoso–arenacea basin was a narrow, northwest–southeast trending, foredeep of Middle–Late Miocene age bounded to the southwest by the Apennine thrust front. The basin configuration and evolution were strongly controlled by tectonics.
Geometrical and sedimentological analysis of Serravallian turbidites deposited within the Marnoso–arenacea foredeep, combined with palaeocurrent data (turbidite flow provenance, reflection and deflection), identify topographic irregularities in a basin plain setting in the form of confined troughs (the more internal Mandrioli sub-basin and the external S. Sofia sub-basin) separated by an intrabasinal structural high. This basin configuration was generated by the propagation of a blind thrust striking northwest to southeast, parallel to the main trend of the Apennines thrust belt.
Ongoing thrust-induced sea bed deformation, marked by the emplacement of large submarine landslides, drove the evolution of the two sub-basins. In an early stage, the growth and lateral propagation of a fault-related anticline promoted the development of open foredeep sub-basins that were replaced progressively by wedge-top or piggy-back basins, partially or completely isolated from the main foredeep. Meanwhile, the depocenter shifted to a more external position and the sub-basins were incorporated within an accretionary thrust belt. 相似文献
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Cretaceous sedimentary rocks of the Mukalla, Harshiyat and Qishn formations from three wells in the Jiza sub-basin were studied to describe source rock characteristics, providing information on organic matter type, paleoenvironment of deposition and hydrocarbon generation potential. This study is based on organic geochemical and petrographic analyses performed on cuttings samples. The results were then incorporated into basin models in order to understand the burial and thermal histories and timing of hydrocarbon generation and expulsion.The bulk geochemical results show that the Cretaceous rocks are highly variable with respect to their genetic petroleum generation potential. The total organic carbon (TOC) contents and petroleum potential yield (S1 + S2) of the Cretaceous source rocks range from 0.43 to 6.11% and 0.58–31.14 mg HC/g rock, respectively indicating non-source to very good source rock potential. Hydrogen index values for the Early to Late Cretaceous Harshiyat and Qishn formations vary between 77 and 695 mg HC/g TOC, consistent with Type I/II, II-III and III kerogens, indicating oil and gas generation potential. In contrast, the Late Cretaceous Mukalla Formation is dominated by Type III kerogen (HI < 200 mg HC/g TOC), and is thus considered to be gas-prone. The analysed Cretaceous source rock samples have vitrinite reflectance values in the range of 0.37–0.95 Ro% (immature to peak-maturity for oil generation).A variety of biomarkers including n-alkanes, regular isoprenoids, terpanes and steranes suggest that the Cretaceous source rocks were deposited in marine to deltaic environments. The biomarkers also indicate that the Cretaceous source rocks contain a mixture of aquatic organic matter (planktonic/bacterial) and terrigenous organic matter, with increasing terrigenous influence in the Late Cretaceous (Mukalla Formation).The burial and thermal history models indicate that the Mukalla and Harshiyat formations are immature to early mature. The models also indicate that the onset of oil-generation in the Qishn source rock began during the Late Cretaceous at 83 Ma and peak-oil generation was reached during the Late Cretaceous to Miocene (65–21 Ma). The modeled hydrocarbon expulsion evolution suggests that the timing of oil expulsion from the Qishn source rock began during the Miocene (>21 Ma) and persisted to present-day. Therefore, the Qishn Formation can act as an effective oil-source but only limited quantities of oil can be expected to have been generated and expelled in the Jiza sub-basin. 相似文献
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关于南海中央次海盆海山火山岩形成背景与构造约束的再认识 总被引：1，自引：0，他引：1
文章拟通过分析南海中央次海盆海山火山岩样品的岩石学及地球化学资料来审视研究区的岩浆过程及其构造背景.综合位于南海中央次海盆的中南、珍贝-黄岩、涨中、宪北、玳瑁、尖峰这6条海山链的火山岩资料及最新分析结果, 将来自各条海山链的洋岛型碱性玄武岩、具有过渡性质的拉斑玄武岩, 以及粗面岩、粗面安山岩、流纹英安岩等纳入统一的岩浆分异体系进行地球化学特征检验.相关参数表明, 中央次海盆海山火山岩岩浆具有连续的演化关系但源区性质并不均一, 属于EMⅠ和DMM双端员混合.根据分析样品的Mg#值、分异指数DI以及主、微量元素的分布特征, 初步判定原始岩浆在上地幔经历了橄榄石、辉石分离结晶作用后继续演化, 产生包括拉斑玄武岩、碱性玄武岩、粗面岩等在内的岩石组合.其中, 富集型OIB的多项地化参数特征表明, 岩浆在演化过程中似有陆壳成分的加入, 这可能是被动大陆边缘破裂留给南海海盆的最重要的遗产之一. 相似文献
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北黄海东部次盆地是我国海域勘探程度较低的一个盆地,钻探已发现该盆地发育中、上侏罗统巨厚暗色泥岩,但目前对该盆地烃源岩的研究尚较薄弱,精细评价该盆地的烃源岩对后续勘探部署具有重要意义。本文利用多口钻井实测数据和地震、测井资料,在层序地层学研究的基础上,应用有机地球化学和有机岩石学等方法,对中、上侏罗统不同层序和同一层序不同体系域中的烃源岩特征进行综合研究,并探讨烃源岩的分布规律及影响因素。东部次盆地烃源岩非均质性特征明显：中侏罗统J2SQ1和J2SQ2层序均以半深湖-深湖相、滨浅湖相暗色泥岩为主,烃源岩有机碳质量分数总体较高（w（TOC）>1.0%）,但生烃潜力指数（w（S1+S2））和氢指数（IH）均很低,且有机质类型差,表明研究区有机质丰度高的烃源岩并非都是生烃能力高的烃源岩,整体为中等-差烃源岩。上侏罗统J3SQ1层序中的烃源岩主要为三角洲前缘和滨浅湖相泥岩,有机质丰度较低,不同体系域发育的均是中等-差烃源岩;J3SQ2层序主要为半深湖-深湖相暗色泥岩,具有厚度大、质纯和横向分布广的特点,但不同体系域中烃源岩的w（TOC）变化很大（0.5%~5.3%）,其中优质烃源岩主要发育在J3SQ2层序中的高位体系域和湖侵体系域中,厚度0~104 m,而低位体系域中发育的则是中等烃源岩,该套优质烃源岩是东部次盆地内最主要的一套油源岩。研究认为,层序地层格架和沉积相控制了东部次盆地烃源岩的空间展布范围,陆源有机质的输入与湖盆原位生物生产力的匹配关系控制了烃源岩的质量,湖盆水体的含氧量与盐度在一定程度上控制了有机质的保存。综上所述,北黄海东部次盆地属于中低丰度的含油气盆地,应在优质烃源岩发育区及其邻区寻找有利勘探目标。 相似文献
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Structural analysis of the Indian Merge 3D seismic survey identified three populations of normal faults within the Exmouth Sub-basin of the North West Shelf volcanic margin of Australia. They comprise (1) latest-Triassic to Middle Jurassic N-NNE-trending normal faults (Fault Population I); (2) Late Jurassic to Early Cretaceous NE-trending normal faults (Fault Population II); and (3) latest-Triassic to Early Cretaceous N-NNE faults (Fault Population III). Quantitative evaluation of >100 faults demonstrates that fault displacement occurred during two time periods (210–163 and 145–138 Ma) separated by ∼20 Myr of tectonic quiescence. Latest Jurassic to Early Cretaceous (145–138 Ma) evolution comprises magmatic addition and contemporaneous domal uplift ∼70 km wide characterised by ≥ 900 m of denudation. The areally restricted subcircular uplift centred on the southern edge of the extended continental promontory of the southern Exmouth Sub-basin supports latest Jurassic mantle plume upwelling that initiated progradation of the Barrow Delta. This polyphase and bimodal structural evolution impacts current hydrocarbon exploration rationale by defining the nature of latest Jurassic to Early Cretaceous fault nucleation and reactivation within the southern Exmouth Sub-basin. 相似文献