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1.
通过对塔里木盆地西北缘巴楚大阪塔格和柯坪水泥厂中—下奥陶统露头剖面的详细观察和研究,并结合塔中地区地震资料对比分析,建立了中—下奥陶统鹰山组至一间房组的高精度层序地层格架和沉积模式。研究表明,中—下奥陶统(鹰山组至一间房组)碳酸盐岩可划分为两个复合(二级)层序(CS1和CS2),其中CS1和CS2又可分出两个和三个三级层序(Sq1—Sq5)。在此基础上依据露头剖面旋回结构变化进一步划分出17~19个高频旋回或四级层序。根据宏观沉积结构和镜下结构特征,总结出的9种微相类型和4种沉积微相组合类型,反映出特定的沉积环境和生物造礁特征,其中包括生物礁-滩复合体、生屑滩、内碎屑滩、氵舄湖和滩间海等。研究还揭示出层序格架中沉积微相组合的发育和演化规律,Sq1—Sq2整体由氵舄湖和滩间海沉积组成,蒸发作用强烈,未见生屑颗粒,发育中细晶白云岩、云质灰岩、含云灰岩等结晶云岩;Sq3时期发育大套厚层内碎屑滩沉积,生屑颗粒开始出现,但数量较少;Sq4时期,砂屑颗粒相对减少,生屑含量大量增加,顶部发育中薄层的生屑滩组合;Sq5时期造礁生物大量出现,以生物礁-滩复合体沉积为主,大致对应于一间房组。  相似文献   

2.
鄂西峡口地区在构造上属中扬子台地北缘,发育了一套比较完整的中、上二叠统海相碳酸盐岩沉积。采用微相分析的方法,对中二叠统栖霞组碳酸盐岩的生物组合、微相类型和沉积环境进行了研究,将峡口地区的栖霞组沉积归纳为7种微相:多类型生物碎屑粒泥灰岩、含大壳体有孔虫的生物碎屑粒泥-泥粒灰岩、粗枝藻粒泥-泥粒灰岩、破碎的生物碎屑粒泥灰岩、具定向排列的藻屑—腕足泥粒灰岩、含内碎屑的生物碎屑泥粒灰岩、含原地珊瑚和藻类的生物碎屑泥粒灰岩。碳酸盐岩微相类型的垂向序列指示了峡口地区的栖霞组形成于碳酸盐岩缓坡环境,其底部地层沉积于内缓坡局限海相,中上部地层为内缓坡边缘低能生物丘相与内缓坡开阔海相的交替沉积。  相似文献   

3.
通过对贵州省凯里黄飘地区红花园组进行地层剖面实测和岩矿样品镜下观察鉴定与分析,共识别出6种碳酸盐岩微相,即:MF-1包壳生物碎屑亮晶灰岩; MF-2生物碎屑泥晶灰岩; MF-3鲕粒亮晶灰岩; MF-4具窗格孔泥晶灰岩; MF-5叠层灰岩; MF-6集合颗粒亮晶灰岩。通过与Flügel(2010)的镶边碳酸盐岩台地标准微相类型进行对比,认为黄飘地区红花园组碳酸盐岩形成于台地边缘滩与滩后(局限台地与开阔台地)沉积相带。综合分析表明黄飘地区下奥陶统红花园组经历了3期相对连续完整的次级海进-海退旋回。  相似文献   

4.
塔里木盆地西部是我国发育中新生代海相地层的少数地区之一。以沉积微相分析为手段,通过对塔里木盆地西北缘乌恰地区库孜贡苏剖面晚白垩世-古近纪岩性、生物组合、颗粒成分、基质类型及其沉积结构和构造特征等仔细研究,重点针对碳酸盐岩划分出(含)骨屑隐晶灰岩、隐晶灰岩、微(隐)晶白云岩、鸟眼隐晶灰岩、微晶鲕粒白云岩、生物碎屑灰岩、微晶球粒白云岩、生物灰岩、亮晶鲕粒灰岩等9个岩相类型。根据碳酸盐岩微相类型组合和剖面结构沉积特征,划分出潮上带、潮间带、潮下带、台地边缘浅滩和生物礁5个沉积相,并恢复了该区晚白垩世-古近纪的沉积环境演化过程,为查清白垩纪-古近纪特提斯洋演化以及重建该地区古环境和油气勘探研究提供重要的基础材料。  相似文献   

5.
结合野外剖面实际观察、测量、岩石取样和室内工作,对巢湖马家山剖面下三叠统南陵湖组中段及上段地层的碳酸盐岩沉积微相特征及其古环境进行了初步的分析和探讨,探讨地层所反映的沉积环境背景。通过对670个岩石薄片的镜下观察,识别出了6种微相:MF1均质泥质泥晶灰岩微相、MF2水平纹层状泥晶灰岩微相、MF3含少量生物碎屑的泥晶灰岩微相、MF4含内碎屑和灰岩卵石的泥晶灰岩微相、MF5瘤状含丰富生物碎屑的泥晶灰岩微相、MF6泥(页)岩微相。推断该地区在斯帕斯亚期中晚期经历了深水盆地—外缓坡两种环境,整体为一个海退过程。  相似文献   

6.
结合野外剖面实际观察、测量、岩石取样和室内工作,对巢湖马家山剖面下三叠统南陵湖组中段及上段地层的碳酸盐岩沉积微相特征及其古环境进行了初步的分析和探讨,探讨地层所反映的沉积环境背景。通过对670个岩石薄片的镜下观察,识别出了6种微相:MF1均质泥质泥晶灰岩微相、MF2水平纹层状泥晶灰岩微相、MF3含少量生物碎屑的泥晶灰岩微相、MF4含内碎屑和灰岩卵石的泥晶灰岩微相、MF5瘤状含丰富生物碎屑的泥晶灰岩微相、MF6泥(页)岩微相。推断该地区在斯帕斯亚期中晚期经历了深水盆地—外缓坡两种环境,整体为一个海退过程。  相似文献   

7.
紫云晚石炭世叶状藻礁发育在碳酸盐岩台地边缘内。研究以碳酸盐岩微相分析为主要手段,对叶状藻礁剖面中岩石的微相特征和沉积环境研究。主要总结出6个微相类型,为生物碎屑粒泥灰岩、生物碎屑泥粒灰岩、球粒生屑泥粒灰岩、叶状藻粒泥灰岩—叶状藻泥粒灰岩、腕足泥粒灰岩、生物碎屑颗粒灰岩。总结了一个在开阔台地与台地边缘过渡带上的局部相模式,由较深水的开阔台地相、叶状藻礁相、台内斜坡相和台内较浅水的斜坡相、较浅水的开阔台地相、台内浅滩相过渡,分析总结了叶状藻礁的沉积环境。微相组合及其在剖面纵向分布规律显示,剖面的总体沉积环境为潮下带浅水开阔台地环境。   相似文献   

8.
重庆石柱漆辽乡下奥陶统可划分为13种沉积微相和5种沉积亚相。结合露头沉积学研究得出该时段沉积环境的演化序列为:南津关组和分乡组下部以灰岩为主,夹陆源碎屑透镜体和鲕粒灰岩,属于局限台地亚相;分乡组的中上部以鲕粒滩和泥页岩为主,属于典型的开阔台地亚相;红花园组的底部以生物碎屑灰岩与泥岩互层为主,红花园的中上部为深灰色巨厚层含燧石结核灰岩、砾屑灰岩夹生物碎屑灰岩,分别属于台地边缘浅滩亚相和台地前缘斜坡亚相;大湾组的生物碎屑灰岩与页岩互层属于内陆棚亚相。综合分析表明研究区下奥陶统是一个水体向上变深的沉积旋回。  相似文献   

9.
本文分析轮南油田中奥陶统一间房组-上奥陶统吐木休克组灰岩生物多样性、沉积序列和时空展布,显示水深加大是控制地层分界上下岩相-生物相变化的主要因素。中奥陶统一间房组台地相沉积期,水体深度多在正常浪基面附近,岩性以中-高能滩相的砂屑生屑灰岩、砂屑灰岩为主并伴有小型台缘礁。从一间房组上部到上奥陶统吐木休克组,生物相-岩相有明显变化,总体表现为水体加深。吐木休克组发育深水缓斜坡型灰岩沉积,向南连接满加尔凹陷,红色灰岩岩性变化小,生屑和内碎屑含量少,灰泥含量显著增加。轮南油田中-晚奥陶世经历了一次从浅海台地演变为沉没台地的持续性海进过程,其岩相转换的时间节点基本与塔里木板块西北巴楚露头区一致,均发生在整合接触的中奥陶统一间房组-上奥陶统吐木休克组界线附近。  相似文献   

10.
塔里木盆地海相碳酸盐岩与油气   总被引:1,自引:0,他引:1  
塔里木盆地碳酸盐岩主要分布于台盆区寒武系—奥陶系,它既可以作为油气的储层和源岩,也可以作为油气的盖层或遮挡体。碳酸盐岩主要发育于碳酸盐岩台地相和斜坡相之中,其中开阔台地及台地边缘坡折带的生物碎屑滩和砂屑滩、局限台地的白云岩坪是主要的储集相带。潜山溶孔溶洞型白云岩、石灰岩及礁滩复合体中的生物碎屑灰岩、砂屑灰岩、鲕粒灰岩、礁灰岩以及潮坪白云岩是主要的储集岩。寒武系—下奥陶统、中—上奥陶统都发育有较好的碳酸盐岩烃源岩。根据油气的分布与聚集特点,对碳酸盐岩油气藏作了分类。论述了塔里木盆地碳酸盐岩油气勘探的前景和重要目标。  相似文献   

11.
Upper Cambrian-Lower Ordovician shoal-facies carbonate rocks are well developed in the Yangjiap-ing section, Shimen, Hunan, and their types are also highly varied. There are both monomictic shoal-facies rocks (e.g. sparite oolitic limestone and sparite calcarenite) and polymictic shoal-facies rocks (e.g. grainstone, whose grain types include sand- and pebble-sized fragments, bioclasts, oolites, algal mats etc.). What is different is that the Upper Cambrian shoal-facies rocks have been mostly strongly dolomitized into shoal-facies dolomite with various residual textures. This paper presents an in-depth study of various kinds of diagenesis and pore space evolution occurring in this section and suggests that the diagenetic sequences of shoal-facies rocks in the study area is dominantly of retrogressive type.  相似文献   

12.
在下/中奥陶统界线附近笔石的生物地层学研究基础上,笔者选择了华南地区奥陶系台地相、盆地相和位于二者之间的过渡相等不同沉积相区5条典型地层剖面,开展了华南下/中奥陶统界线附近笔石动物群的图形对比研究,通过这项研究,进一步明确了华南奥陶系下/中奥陶统界线附近笔石动物群的延限和不同相区笔石动物群的精确对比关系,为开展不同相区之间地层的精确对比奠定了基础。  相似文献   

13.
This study presents an example of locating Cambrian–Ordovician boundary in the lower Paleozoic carbonate succession in Korea using carbon isotope stratigraphy. The Yeongweol Unit of the lower Paleozoic Joseon Supergroup comprises the Upper Cambrian Wagok Formation and the Lower Ordovician Mungok Formation in the Cambrian–Ordovician transition interval. Conventionally, the boundary was placed at the lithostratigraphic boundary between the two formations. This study reveals that the boundary is positioned in the basal part of the Mungok Formation based on the carbon isotope stratigraphy coupled with biostratigraphic information of conodont and trilobite faunas. The δ13C curve of the Lower Ordovician Mungok Formation shows a similar trend to that of the coeval stratigraphic interval of Argentine Precordillera (Buggisch et al., 2003), suggesting that the δ13C curve of the Mungok Formation reflects the Early Ordovician global carbon cycle.  相似文献   

14.
Abstract: Upper Cambrian‐Lower Ordovician shoal‐facies carbonate rocks are well developed in the Yangjiaping section, Shimen, Hunan, and their types are also highly varied. There are both monomictic shoal‐facies rocks (e.g. sparite oolitic limestone and sparite calcarenite) and polymictic shoal‐facies rocks (e.g. grainstone, whose grain types include sand‐ and pebble‐sized fragments, bioclasts, oolites, algal mats etc.). What is different is that the Upper Cambrian shoal‐facies rocks have been mostly strongly dolomitized into shoal‐facies dolomite with various residual textures. This paper presents an in‐depth study of various kinds of diagenesis and pore space evolution occurring in this section and suggests that the diagenetic sequences of shoal‐facies rocks in the study area is dominantly of retrogressive type.  相似文献   

15.
The Huanghuachang section near Yichang, southern China meets the requirements of Global Stratotype Section and Point (GSSP) for the base of the Middle Ordovician Series and the yet-to-be-named third stage of the Ordovician System (or lower stage of Middle Ordovician Series). The conodont succession at the section is complete across the Lower to Middle Ordovician series boundary and several excellent phylogenetic lineages of Baltoniodus, Trapezognathus, Periodon, and Microzarkodina are represented. The definition of the base of the Middle Ordovician is proposed to be the first appearance datum (FAD) of Baltoniodus? triangularis in the section. It is followed closely by the FAD of Microzarkodina flabellum, which is taken as a reasonable proxy for the boundary. This level approximates the boundary between the lower and upper intervals of the Azygograptus suecicus graptolite Biozone, and nearly coincides with the base of the Belonechitina henryi chitinozoan Biozone.The proposed GSSP for the base of the international Middle Ordovician Series is located in a roadside exposure at the base of Bed (SHod) 16, 10.57 m above the base of the Dawan Formation in the measured Huanghuachang section near Yichang City, southern China. The same faunal succession is also recorded from the Chenjiahe (formerly Daping) section, 5 km to the north of the Huanghuachang section. The proposed boundary horizon can be recognized and correlated globally with high precision in both relatively shallow-water carbonate facies as well as in deep-water graptolite facies.  相似文献   

16.
中国奥陶系和下志留统下部年代地层单位的划分   总被引:1,自引:2,他引:1  
十多年来全球和我国奥陶系和下志留统下部年代地层研究取得很大进展 ,在前人所积累的大量成果和资料的基础上 ,结合近年来的研究 ,厘定了我国奥陶系和下志留统下部年代地层单位系统 ,建议分别以吉林浑江大阳岔 (或江西武宁或湖北宜昌黄花场 )、湖北宜昌黄花场、浙江常山黄泥塘、新疆柯坪大湾沟和湖北远安苟家垭剖面为界线层型 ,将中国奥陶系自下而上划分为 :新厂阶 (或特马豆克阶 )、道保湾阶、大湾阶、达瑞维尔阶、艾家山阶和钱塘江阶。为了客观反应我国奥陶系的特点 ,同时便于与全球年代地层单位界线对比 ,建议将上述各个阶底界的的界线依次划在 R.taojiangensis( =R.praeparabola) / H .simplex、 O.communis、 B.triangularis/ T.laevis、 U.austrodentatus、 N .gracilis和 N ankinolithus带的底部 ;中下奥陶统和中上奥陶统之间的界线分别定在道保湾阶 /大湾阶和达瑞维尔阶 /艾家山阶之间。建议下志留统最下部两个年代地层单位——龙马溪阶和大中坝阶——以湖北宜昌王家湾剖面为界线层型 ,分别以 A.ascensus和 D .triangulatus的首现为划分标志。对每一个阶的命名、含义、界线层型剖面的岩性特征、界线划分的生物标志、与全球相关年代地层单位层型和点 ( GSSP)的对比 ,以及与过去曾经建议或使用过?  相似文献   

17.
In the Precordillera of western Argentina, an isolated outcrop of Llandeilian siliciclastics and Caradocian limestones (Rio Sassito succession) reveals a complex interplay between the tectonic and the sedimentary history of the Precordillera during Middle and Late Ordovician times. The succession is composed of a lower siliciclastic interval and an upper carbonate interval and is bounded below and above by erosional unconformities. Dating of these unconformities, which in many places merged to form one single surface, demonstrates that the most important erosional event took place prior to the deposition of the Rio Sassito succession. This erosional event is correlated to extensional tectonics during continental breakup and the separation of the Precordillera from Laurentia. Block faulting with the formation of horst and graben structures provided the topography for the establishment of a pelagic carbonate platform during the Caradoc. In our view, there are no indications that these phenomena are related to the accretion of the Precordillera to Gondwana or to the formation of an Ordovician supercontinent. The carbonate sediments are typical of temperate-water settings, characterized by the absence of ooids, oncoids, and algae, and by the presence of abundant abraded bioclasts, intraclasts, and peloids. The inference of a temperate-water environment does not, as previously supposed, indicate the accretion of the Precordillera to Gondwana, but is more likely related to global cooling prior to the Ashgillian glaciation.  相似文献   

18.
本文对唐山和卢龙地区寒武-奥陶系界线地层中的牙形刺再次进行研究,厘定了过去报道的一些重要属种,并对最具地层意义的Cordylodus的几个种的演化进行了分析。指出了该属的两个进化系列,第一支进化系列是Eoconodontusnotchpeakensis-Cordylodusprimitivus-C.proavus-C.caboti-C.intermedius-C.angulatus;而另一支则是Eoconodontusnotchpeakensis-C.caboti-C.prolindstromi-C.lindstromi-C.prion。本文对寒武-奥陶系界线的几个划分方案也进行了简单的讨论  相似文献   

19.
贵州长顺代化石炭系中间界线的沉积相研究   总被引:3,自引:3,他引:3  
周志澄 《地层学杂志》1994,18(1):1-8,T002
在碳酸盐微相的详细研究基础上,贵州长顺代化下、上石炭统剖面由下至上可分出5个主要沉积相:盆地相、开阔海陆架相、下斜坡相、中斜坡相和上斜坡相,下、上石炭统界线处于连续沉积的中斜坡相内。  相似文献   

20.
鄂尔多斯盆地南缘奥陶纪层序地层分析   总被引:1,自引:0,他引:1  
通过野外实测剖面、钻井、测井资料的研究,识别出8个层序界面,划分出7个三级层序.其中冶里组为SQ1,亮甲山组为SQ2,马家沟组两个(SQ3、SQ4),平凉组两个(SQ5、SQ6),背锅山组一个(SQ7).层序SQ1-SQ6只发育海侵体系域及高位体系域,层序SQ7发育低位体系域及海侵体系域,高位体系域被构造剥蚀.SQ1-...  相似文献   

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