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31.
冀中饶阳凹陷大王庄地区古近系属断陷湖盆演化阶段,分为断陷分割期、断陷扩张期和断陷萎缩期3个时期,发育辫状河三角洲、滨浅湖和曲流河3类沉积体系。在等时地层格架内,分析了该地区沉积演化特征和储盖组合的分布及时空展布规律,指出该区古近系主要发育沙三段、沙二段、沙一段和东营组4套储盖组合,其中沙一段储盖组合为最有利的含油储盖组合。  相似文献   
32.
采用井-震联合地层恢复法,对辽东湾辽东带中南部的古近纪进行了古地貌恢复。在此基础上拓宽了坡折带研究,将古地貌(包括古坡折带、古沟谷、古凸起等)纳入古物源供给系统的框架内探讨其对沉积体系的控制作用。分析表明:在构建完整物源供给系统的前提下,古地貌诸单元及其组合样式对沉积体系有着明显的控制作用。主要表现为:不同级次的物源体系导致沉积体类型和规模存在差异;物源区沟谷的分布及其赋存时期制约着砂体的主要分布位置、时期及规模;坡折带样式决定砂体的类型、规模及分布;古地貌组合样式控制储集体的成因、富集位置和规模大小。因此,古地貌分析对储层的预测和识别具有明显的指导作用。勘探实践证明,将其与常规储层预测方法联用,能够很大程度地提高储层预测的精度。  相似文献   
33.
山东济阳坳陷东营凹陷牛庄地区沙三段层序地层分析是在三级层序划分的基础上,通过对沉积体系发育特征和气候旋回单元的识别和解剖,建立了高精度层序地层单元的基本构型。气候旋回包含了从干旱枯水期到潮湿湖泛期的完整过程,沉积响应为受湖平面变化、沉积物供给等因素控制的多种方式叠置的湖底扇和前积体等,多期气候旋回叠合构成了湖泊层序的基本面貌。通过气候旋回的识别,可以对不同级别层序间的包含关系,以及高精度层序的内部构成进行分析和讨论。  相似文献   
34.
李守军 《地质论评》1998,44(1):31-34
本文通过对渤海湾盆地下第三系中半咸水化石纵向分布特点研究,并根据新的地层划分方案,利用古生物-岩相综合分析方法绘制了该地区早第三纪水平面升降曲线,发现半咸水生物出现在水进初期,在最大水进期消失,水平面升降曲线一全球海平面升降曲线无直接关系,即水平面的上升示受海平面上升的影响,从而证明此阶段无海侵发生,非海侵观点对于总结我国陆相地层的油气勘探理论及实践具有重要意义。  相似文献   
35.
微体化石在解决地层的归属问题上发挥了重大作用,根据新发现的几丁虫将苏泰103井的"上震旦统陡山沱组"、都4井的"中下侏罗统象山群"、葛9井的"葛村组"地层修改归属于志留系,纠正了以前的错误地质结论。在草9井的钻进过程中,根据孢粉化石确定已钻至浦口组,推测油气目的层已钻过或缺失,提前473.03m终孔,节省了钻井费用,创造了无形产值。  相似文献   
36.
鲁东古近纪煤田含煤地层特征及找煤方向分析   总被引:1,自引:0,他引:1  
昌乐五图煤田和黄县煤田是鲁东地区发现的两个古近纪煤田,含煤地层时代属于中始新世,均为富含褐煤和油页岩的沉积建造。煤系中部均发育一段厚度20~30m的紫红色砂砾岩夹泥岩(或粘土岩),将煤系分为上下两部分;煤系底部为厚层杂色砂砾岩、砾岩和角砾岩等粗碎屑岩,具有很好的可比性。推断在黄县煤田向西到羊角沟沿海一带,五图煤田以东的潍坊—昌邑一带和以西的昌乐、临朐、益都等地,可能有同层位煤系赋存,建议将这些地区作为找煤重点区域。  相似文献   
37.
The present study of five wells from Upper Albian to Lower Maastrichtian succession in the southwestern Barents Sea yields the first dinoflagellate cyst-based palynological event biostratigraphy for the area. The research focuses on the Upper Cretaceous Kveite and Kviting formations due to the lack of formal palynological documentation, and enables the formation of a biozonation of greater resolution than currently achievable by micropalaeontology. Four new interval zones and one abundance subzone are described, from base upward: Palaeohystrichophora infusorioides and Palaeohystrichophora palaeoinfusa Interval Zone (intra Early Cenomanian–intra Late Cenomanian), Dinopterygium alatum Interval Zone (?intra Early Coniacian–Late Santonian), Palaeoglenodinium cretaceum Interval Zone (Early Campanian), and the Chatangiella bondarenkoi Interval Zone (Late Campanian) encompassing the Heterosphaeridium bellii Abundance Subzone (intra-Late Campanian). The zones are well correlated to existing palynological zonations from the Norwegian–Greenland Sea, where the previously described Subtilisphaera kalaalliti Interval Zone (intra Late Albian–?intra Early Cenomanian), Heterosphaeridium difficile Interval Zone (Middle Turonian to ?intra Early Coniacian) and Cerodinium diebelii Interval Zone (Early Maastrichtian) are recognised. These data also reveal the presence of three significant unconformities of Late Cenomanian–Early Turonian, Middle Campanian and Late Maastrichtian–Paleocene age.  相似文献   
38.
The Cretaceous–Paleogene boundary (KPgB) was dated by the 40Ar/39Ar method herein from the western interior of North America at 65.48 ± 0.12 Ma (1σ), in good agreement with other recent published estimates. For the Deccan Traps, India, new argon ages as well as others available in the literature, are assessed for reliability based on (a) statistical reliability of plateau/isochron sections and (b) freshness of material dated utilizing the alteration index method. From tholeiitic lavas from the Composite Western Ghats Section (CWGS), only six ages are found to be reliable estimates of the time of crystallization. These ages along with the magnetic polarity of the lavas agree with the geomagnetic polarity time scale (GPTS) at ∼67–64 Ma. Alkaline rocks from the Anjar area of Kutch, provide three reliable ages that suggest a hiatus in lava extrusion around KPgB. For the Rajahmundry basalts, the upper flow’s age defines its formation during chron 29n; a single age from the lower reversed polarity flow appears somewhat dichotomous when plotted against the GPTS. The reliable lava ages indicate the most voluminous (reversed polarity) sections of the CWGS were extruded at a time statistically indistinguishable from that of the KPgB. The Deccan Trap – KPgB faunal extinction hypothesis remains plausible, but must compete with the latest report, favoring a very close temporal connection (∼0.03 m.y.) between the Chixculub (Impact) Crater and the KPgB.  相似文献   
39.
黑龙江省东部七星河盆地是一新生代聚煤盆地,其含煤地层为古近系宝泉岭组、新近系富锦组。宝泉岭组由各级砂岩、泥岩、炭质泥岩以及褐煤组成,发育滨浅湖相、深-半深湖相、三角洲平原相,属于湖泊沉积体系、三角洲沉积体系。富锦组主要由泥岩、粉砂岩、中砂岩、含砾粗砂岩及煤层、炭质泥岩、硅藻岩组成,发育滨浅湖相、扇三角洲平原相,分别属于湖泊沉积体系和扇三角洲沉积体系。层序SI相当于宝泉岭组,发育低位体系域、湖侵体系域和高位体系域,煤层主要发育高位体系域中后期,成煤环境以滨浅湖淤积沼泽为主。层序SII相当于富锦组,主要发育湖侵体系域、高位体系域,局部地区发育低位体系域,煤层亦主要发育高位体系域中后期,成煤环境以扇三角洲淤积沼泽和滨浅湖淤积沼泽为主。层序SI、SII的高位体系域中后期,盆地基底沉降速率和物源供给处于相对平衡状态,主要发育了扇三角洲淤积沼泽、滨浅湖和滨浅湖淤积沼泽环境,发育可采煤层。  相似文献   
40.
Plant-derived terpenoids, long recognized as biomarkers, can help reveal the major taxonomic groups of land plants present in ancient environments, even if rocks and sediments do not preserve plant macro- or microfossils. Previous studies have used simple di- to triterpenoid ratios to reconstruct floral changes in the geologic past, but few have compared terpenoid ratios with estimates of floral composition from fossils. Further, reconstructions have not taken into account differences in biomarker production (i.e. concentration relative to leaf biomass) between different types of plants. Here, we have examined terpenoids from early Cenozoic fluvial rocks from the Bighorn Basin (Wyoming, USA), where fossil flora has been studied in detail. We analyzed the distributions of diterpenoids, triterpenoids and n-alkanes from leaf wax in a total of 43 samples from 15 stratigraphic horizons of late Paleocene (63 Ma) to early Eocene (53 Ma) in age. In nearly all samples, triterpenoids, derived from angiosperms, were significantly lower in abundance than conifer-specific diterpenoids, a finding that contrasted with plant fossil evidence for the same rocks. This suggests that di- to triterpenoid ratios severely underestimate the abundance of angiosperms in paleovegetation. Angiosperms dominated n-alkane production among modern plants, and we propose a new paleovegetation proxy based on the ratio of diterpenoids (conifers) to n-alkanes (angiosperms), corrected for lipid production estimated from extant vegetation. Using diterpenoids and alkanes, we infer the composition of paleovegetation to be similar to that inferred from plant fossils. Although the approach works well for the Bighorn Basin, we stress the new paleovegetation proxy will need to be evaluated for other time periods, communities, paleogeography and depositional environments with pollen or megafossil data available.  相似文献   
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