Depositional features and sedimentary model of Buqu Stage in Mid-Jurassic in Qangtang Basin, Xizang （Tibet）, China

The largest Mesozoic northward transgression in Qangtang Basin of Qinghai-Xizang (Tibet) Plateau occurred during the Buqu Stage, Middle Jurassic. Mainly filled with carbonate rocks, the whole basin is composed of transgression-regression sedimentary cycle. Field outcrops and indoor analysis revealed 8 types of sedimentary facies markers in this region. 4 types of sedimentary facies have been recognized: platform facies,platform marginal facies, foreslope facies and basin facies. Influenced by the northern Lazhuglung-Jinshajiang suture zone, central uplift region and southern Bangongco-Nujiang suture zone, these facies belts extended east-west. The sedimentary model was established based on observed depositional features. From their biological features and sedimentary characteristics, it is suggested that the paleoclimate was warm and humid at that time.The Buqu Formation is a promising target for oil and gas exploration in Shuanghu-Duoyong area in future.     

柴西地区上下油砂山组沉积相及有利储层

通过对研究区露头、岩性、测井等特征的研究,将柴达木盆地新近纪上下油砂山组划分出5种重要的沉积相类型:冲积扇相、河流相、扇三角洲相、三角洲相、湖泊相,并进行详细描述。依据单因素分析多因素综合画图的方法论,做出上下油砂山组沉积相平面展布图。沉积相带是控制储层特征和分布的基本因素。结合沉积相带图,划出油砂山组储集相带,有利储集相主要是三角州前缘砂体,冲积扇—扇三角洲分流河道砂体,浅湖滩坝;主要分布在沙西、乌南、咸水泉、月牙山、红沟子、阿尔金斜坡带,而碱山地区的储集相带发育较差。     

胶莱盆地东缘早白垩世莱阳群沉积序列及岩相古地理

胶莱盆地东缘早白垩世早期莱阳群沉积体现了湖盆由开始形成—鼎盛—萎缩消亡的全过程,发育由冲洪积相—湖相—三角洲相—河流相沉积的完整序列,且由东至西,由湖相到河流相逐渐过渡;古水流方向显示莱阳期盆地中心位于朱吴断裂、海阳断裂带之间,以断裂带为界,以西水流方向大致为由NW至SE向,以东水流方向则为由SE至NW向;早白垩世早期莱阳期盆地的形成与演化明显受区域性牟(平)-即(墨)断裂带活动所控制。     

Sequence associations of sedimentary facies in continental basins and their applications to palaeogeographic mapping

According to the characteristics of sedimentary facies and their vertical associations, sequence association of sedimentary facies can be divided into 2 types and 28 subtypes. The first type (type A) is a sedimentary sequence without volcanic rocks, including 18 subtypes. The second type (type B) is a volcanogenic succession including 10 subtypes.Each subtype may reflect certain filling condition under certain sedimentary environment. Time and space distribution of different types of sequence associations can reflect tectonics that controlled the basin evolution, sedimentary environments and palaeogeography.     

Sequence associations of sedimentary facies in continental basins and their applications to palaeogeographic mapping

According to the characteristics of sedimentary facies and their vertical associations, sequence association of sedimentary facies can be divided into 2 types and 28 subtypes. The first type (type A) is a sedimentary sequence without volcanic rocks, including 18 subtypes. The second type (type B) is a volcanogenic succession including 10 subtypes. Each subtype may reflect certain filling condition under certain sedimentary environment. Time and space distribution of different types of sequence associations can reflect tectonics that controlled the basin evolution, sedimentary environments and palaeogeography.     

大巴山南坡奥陶系的沉积环境分析

本文系统地研究了大巴山南坡奥陶系的沉积特征,详细地划分了该系各组段的沉积相,并建立了奥陶系的沉积相模式。奥陶系以发育潮坪相为特征,并有少量浅海沉积。奥陶纪时期,本区处于北为汉南古陆与巴山隆起,南为广阔的陆表海盆地的古地理环境。尽管各个时期海岸线有进有退,海水有深有浅,但盆地地形的总趋势是西北高而东南低,海侵的旋回性与沉积发展的周期性相一致。     

广西岑溪地区泥盆系志留系地质特征及其意义

广西岑溪地区志留系为半深、深海笔石相—滨浅海腕足相的碎屑岩地层序列，属地槽型沉积产物；泥盆系为滨岸碎屑岩相—台地碳酸盐岩相—槽盆硅质岩相的地层序列，富含鱼、腕足等多门类化石，具地台型沉积特征。泥盆系与志留系之间为平行不整合接触。表明广西运动在本区表现为整体抬升遭受剥蚀而非强烈的造山运动，其集中暴发时间在早泥盆世早期，前奏可追溯到中志留世。由于这一运动，结束了本区早古生代地槽的发展历史，此后进入准地台发展阶段，导致钦州地槽博白—玉林拗陷未能延至本区。     

新立油田嫩江组三段沉积微相分析

根据岩心、测井、粒度分析等资料,研究新立油田嫩江组三段(简称嫩三段)3个砂组的沉积微相,编制嫩三段3个砂组沉积微相平面展布特征图,分析各砂组沉积微相的类型及特征.结果表明:新立油田嫩三段发育于宽缓的拗陷盆地,基底沉降稳定,砂组—小层具有厚度较为协调、地层旋回性强的特点.该段发育于湖盆萎缩时期,下覆嫩二段地层为大段湖相泥岩沉积,三角洲进积进入本区,形成储层发育层段,为新立油田提交探明储量、动态分析开发调整方案提供地质依据.     

牵引流化重力流沉积过程与堆积机制:以渤海湾盆地歧口凹陷为例

以具备牵引流特色的重力流沉积体为载体的高效储集体,是陆相湖盆沉积学研究与勘探突破的重要领域.渤海湾盆地歧口凹陷沙一段发育的大规模多期次陆相重力流具有其沉积特征的独特性(面积约940km2,纵向分布厚度约1.1km).依据水动力条件及沉积过程机制,存在层级递进继承型、渐进过渡型、兼并融合型3种牵引流与重力流动力学过程,细分为泥质碎屑流、砂质碎屑流、过渡型同生流、(高密度-低密度悬浮)似涌浪浊流、(高密度-低密度)准稳态浊流5种机制类型,并依据其发育背景识别出了滨海地区中央隆起带上以重力流水道为主导特征的水道型重力流沉积体系和受次洼地貌控制的面流型重力流.本研究细化了沉积动力学过程-堆积机制-沉积相-岩相一体化的关联性,确定了牵引流化重力流发育的关键控制因素.作为极具潜力的优质储层目标,陆相牵引流化重力流沉积体的研究成果在丰富理论体系的同时,对油气勘探新领域的拓展与突破具重要意义,具备生产实践价值,对于其他陆相湖盆油气勘探具有重要的借鉴作用.     

A preliminary study on the tectonics and evolution of the Fujian Coast Changle—Nanao metamorphism zone

The Fujian coast Changle—Nanao metamorphism zone rocks are composed of gneiss, schist and hornblendite which had gone through metamorphism of amphilbolite facies, and followed the large-scale intrusive mass of gneissic granite. The zone was originally composed of Early Palaeozoic continental margin and island arc volcanic and sedimentary rocks. In 180-150 Ma, the zone underwent ductile shear deformation and amphibolite facies metamorphism; and in 130-80 Ma, rose rapidly and collided with the Southeastern China continental margin volcanic rocks along the NE trending ductile shear belt. The above geologic setting laid the present Fujian coast tectonic foundation whose formation and evolution are known to be interrelated with the subduction and collision of the Taiwan. Central Range. Contribution No. 2589 from the Institute of Oceanology, Chinese Academy of Sciences. The project was supported by NSFC (No. 49472148).     

塔里木盆地塔中-古城地区寒武系沉积体系发育特征与演化

塔里木盆地寒武系油气勘探在塔中与古城地区相继获得较大发现,但对该地区沉积体系的刻画仍以盆地尺度的岩相古地理编图为依据,缺乏多资料约束下的精细研究。通过岩石学分析对塔中—古城地区寒武系白云岩的原岩进行了细致恢复,其中塔中中下寒武统原岩以泥灰岩、(含膏)粒泥灰岩为主,上寒武统则以粒泥灰岩及颗粒灰岩为主;古城地区原岩多为粒泥灰岩、泥粒灰岩及颗粒灰岩。以地球化学研究为手段,恢复了寒武纪碳酸盐岩沉积期古环境,总体上从早寒武世到晚寒武世,水体深度逐渐增加,盐度降低,蒸发作用减弱。在此基础上,以威尔逊碳酸盐岩综合相模式为指导,划分出了3类沉积相、4类亚相、6类微相。利用三维地震资料的精细解释,刻画了古城地区台缘带礁滩体的发育特征及演化规律,4期礁滩体呈进积式向盆地方向迁移。台缘带礁滩体的迁移演化与台内沉积物的发育特征表明古城台缘带的礁滩体的发育与消亡对塔中台内沉积环境存在较大影响。台缘带的快速生长对台内水体形成围陷,造成了含膏碳酸盐岩的沉积,台内与台缘沉积物形成了良好的对应关系。      

松辽盆地东南缘西丁家地区营城组沉积相分析

松辽盆地东南缘深层沉积相研究程度较浅,以西丁家地区营城组为例,利用岩心观察描述结果,结合测井、地震资料,以及区域构造演化和沉积相分析结果,研究松辽盆地东南缘深层地层沉积相.结果表明:营城组(K1y)主要发育扇三角洲、辫状河三角洲、湖底扇和湖泊4种相类型,其中辫状河三角洲相和湖泊相最为发育;西丁家地区营城组主要表现为"广盆浅水"沉积特征,西南陡坡带发育扇三角洲沉积体系,北部斜坡带发育辫状河三角洲沉积体系,垂向上地层叠加样式表现为由进积向加积演变.该研究结论对西丁家地区深层地层下一步勘探开发及资源评价具有指导意义.     

The Holocene Environmental Evolution of the Inner Hangzhou Bay and Its Significance

The Holocene environmental evolution in coastal area, including deltas and estuaries, is vital to the Neolithic colonization in the eastern China. A 29-m long sediment core XL was obtained from the region between the Taihu Lake and Qiantang Estuary, and multiple analyses on the core sediments have been done to investigate the evolution history of the inner coastal zone of Hangzhou Bay during the Holocene. Six sedimentary facies are identified since the late Pleistocene, including the paleosol at the bottom, overlain by tidal-flat-channel complex(TFC), tidal-distributary-channel(TDC), inner estuarine basin(IEB), subtidal-to-intertidal-flat, and fluvial-plain facies. The TFC and TDC facies are dated to be formed before 8500 cal yr BP, featured by relatively coarse sediments, high magnetic properties and less abundant foraminifera, denoting the tide-influenced setting with large terrestrial inputs. The IEB facies characterized by the most abundant foraminifera fossils and the lowest sediment magnetic properties, is inferred to be deposited during the maximum flooding period between 8500 and 7900 cal yr BP. The branch estuary was then infilled by local sediments with a shallowing-upward subtidal-to-intertidal sequence during 7900–4300 cal yr BP. At last the fluvial plain system developed since no later than 4300 cal yr BP, favouring the rapid development of Neolithic cultures in the region.     

宜昌斜坡区南华系-震旦系断坳结构发现及其地质意义

宜昌斜坡区钻获南方复杂构造区下寒武统水井沱组、下震旦统陡山沱组高含气页岩，首次实现了古老层系页岩气重大发现，南华系-震旦系构造-沉积格局是认识盆地构造属性及古老页岩气富集的关键。基于前人的研究成果，开展了宜昌地区南华系-震旦系沉积岩石特征、地震资料分析。结果表明:宜昌及周缘存在克拉通内Ⅰ型(宜昌型)、克拉通边缘过渡区Ⅱ型(长阳型)断坳结构控制的沉积区类型。在经历了早期断陷、中期成冰、断坳转换及晚期坳陷4个演化阶段，断坳结构控制了陡山沱组及灯影组-水井沱组Ⅰ_Ⅰ型台地边缘-斜坡和Ⅰ_Ⅱ型台内洼地及Ⅱ型陆棚相沉积区，富有机质页岩相对发育。结论认为:Ⅰ型、Ⅱ型断坳结构发育区是陡山沱组-水井沱组自生自储页岩气的规模聚集区；Ⅰ型控制下灯影组旁生侧储边缘滩也是天然气聚集的有利场所。      

喷气沉积矿床成因研究的几个问题

大的喷气沉积型矿床可能由穿过盆地沉积柱进入基底岩系的热水对流房排放到海底形成。热液对流模式已经取得多方面地质地球化学证据及流体动力学的定量检验。喷气成矿作用是在很长地质历史时期中广泛发育的一种重要成矿作用。大陆边缘断裂槽中的深囟水盆及相邻的碳酸盐台地上的沉陷洼地都是有利的成矿环境。     

论大巴山西段晚二叠世地层发育规律

本文介绍了陕南西乡峡口地区上二叠统地层问题,着重研究了其在大巴山西段的发育规律。据其组合类型,可划分出台地相区、台坡相区和台沟相区等三个沉积相区。对长兴期的大隆组与吴家坪组的相变问题,本文则进一步提出:在横向上,它们是同期异相;在纵向上,它们在过渡的台坡相区内表现为大隆组在上,并随着背离台地相区距离的增加,大隆组的厚度比增大。根据(竹蜒)和有孔虫的产出,对晚二叠世地层提出了分带意见,并依据岩性、岩相、古生物以及沉积间断现象存在与否,指出了二叠系与三叠系在台地相区是平行不整合,在台坡或台沟相区是整合的结论。     

中元古代鄂尔多斯盆地南缘裂谷沉积相与震积岩序列

鄂尔多斯盆地南缘中元古代处于拉张期,发育多裂谷系.分析鄂尔多斯盆地野外地质调查、物探和钻井等资料,划分沉积相剖面,研究沉积演化及相类型.结果表明:盆地南缘中元古代沉积陆相三角洲至海陆过渡相的长城系与滨浅海至深海盆地相的蓟县系,并于蓟县系中发现液化底劈构造、震褶岩、震裂岩、震浊积岩、津浪丘状层和风暴岩等震积岩序列单元;沉积水体逐渐加深,为裂谷非补偿型沉积,蓟县系中存在震积岩序列,反映该区中元古代盆地南缘处于裂谷带内,受裂陷作用持续影响.通过沉积相及震积岩序列划分耦合裂谷说,为区域构造研究提供佐证.     

黔北镇远地区三丘田剖面寒武系明心寺组上段滨岸相沉积特征及其地质意义

沉积环境分析是古地理重建的核心内容,黔北地区寒武系明心寺组沉积环境研究存在较大争议,以致对中上扬子地区明心寺组沉积期古地理格局的认识不能统一。选取寒武系明心寺组发育齐全、出露良好的黔北镇远地区三丘田剖面为研究对象,通过野外剖面观察、室内薄片鉴定及碎屑岩粒度分析等方法对三丘田剖面明心寺组岩石学特征、沉积构造、沉积演化序列、沉积相类型进行了详细分析。结果表明:黔北镇远地区三丘田剖面寒武系明心寺组上段发育大套的石英粉-细砂岩,沉积构造以低角度冲洗交错层理为主,碎屑颗粒的成分和结构成熟度均较高;三丘田剖面明心寺组上段砂岩以双次跳跃组分为主,悬浮组分含量较少,纵向剖面自下而上显示为浅水陆棚→临滨→前滨→后滨演化序列,呈典型的陆棚相向滨岸相变化。综上所述,黔北镇远地区三丘田剖面寒武系明心寺组上段的沉积相为滨岸相。黔北镇远地区明心寺组滨岸相沉积的出现,指示了黔北地区区域上重新认识明心寺组沉积相的必要性,将直接影响对黔北地区乃至中上扬子地区寒武纪古地理格局及其大地构造背景的认识。     

内蒙古东南部开鲁盆地龙湾筒九佛堂组火山岩地质特征

开鲁盆地为陆相火山岩盆地。勘探结果表明，在陆相火山岩盆地中获得了工业油流，为寻找石油油藏开辟了新途径。龙湾筒凹陷的火山岩以火山熔岩、火山碎屑沉积岩为主，根据岩石特征，可划分为三种岩相：溢流相、火山爆发相和火山沉积相。溢流相以熔岩为主，包括安山岩、粗面岩、粗安岩、玄武岩和玄武安山岩；火山爆发相岩石包括火山角砾岩和凝灰岩；火山沉积岩相岩石包括凝灰质砂岩、凝灰质泥岩。依据火山岩相划分，结合火山岩测井和地震反射特征，对龙湾筒凹陷火山岩纵向上的变化和平面上的展布进行了讨论，特别是对储集性能好的溢流相岩石进行了圈定。     

广西泥盆纪最早的生物礁

广西泥盆纪的沉积相可划分为滨岸碎屑岩相、碳酸盐台地相和陆间海槽相等三个相区。其中最早的碳酸盐台地形成始于早埃姆斯阶晚期,同时伴生小型生物丘和在台地边缘发育的小点礁。本文讨论了广西具代表性的德保钦甲点礁,为一点礁—泥丘组合。