Types,characteristics and geological significance of event deposits of Chang 9 Member of Triassic Yanchang Formation in southwestern Ordos Basin,NW China

Through core observation,thin section identification,and logging and testing data analysis,the types and characteristics of event deposits in the ninth member of Yanchang Formation of Triassic(Chang 9 Member)in southwestern Ordos Basin,China,are examined.There are 4 types and 9 subtypes of event deposits,i.e.earthquake,gravity flow,volcanic and anoxic deposits,in the Chang 9 Member in the study area.Based on the analysis of the characteristics and distribution of such events deposits,it is proposed that the event deposits are generally symbiotic or associated,with intrinsic genetic relations and distribution laws.Five kinds of sedimentary microfacies with relatively developed event deposits are identified,and the genetic model of event deposits is discussed.Seismites are mainly developed in the lake transgression stage when the basin expands episodically,and commonly affected by liquefaction flow,gravity action and brittle shear deformation.Gravity flow,mainly distributed in the high water level period,sandwiched in the fine-grained sediments of prodelta or semi-deep lake,or creates banded or lobate slump turbidite fan.It is relatively developed above the seismites strata.The volcanic event deposits are only seen in the lower part of the Chang 9 Member,showing abrupt contact at the top and bottom,which reflects the volcanic activity at the same time.Anoxic deposits are mostly formed in the late stage of lake transgression to the highstand stage.Very thick organic-rich shales are developed in the highstand stage of Chang 9 Member,and the event deposits in the depositional period of these shales are conducive to potential reservoirs.

Late Carboniferous-Early Permian Volcanic Event Deposits and Stratigraphic Correlation in Shandong Province and Its Adjacent Regions

Deposits of 10 volcanic events of 6 stages have been discovered by the authors after detailed field and lab studies of the Benxi and Taiyuan Formations in Shandong Province and its adjacent regions. They show certain temporal-spatial distribution characteristics. Volcanic fragments were probably derived from two different volcanic sources north and south of the North China Platform, while the magma of the two volcanic sources was probably derived from the lower crust. A new stratigraphic correlation scheme is put forward for the Benxi and Taiyuan Formations in this region on the basis of previous biostratigraphic work with the regionally widespread volcanic event layers as the marker bed for the isochronous stratigraphic correlation on a super-regional scale and in conjunction with the maximum transgressive event layers.

Genesis of granular calcite in lacustrine fine-grained sedimentary rocks and its indication to volcanichydrothermal events: A case study of Permian Lucaogou Formation in Jimusar Sag, Junggar Basin, NW China

Granular calcite is an authigenic mineral in fine-grained sedimentary rocks.Core observation,thin section observation,cathodoluminescence analysis,fluid inclusion analysis,scanning electron microscope(SEM),and isotopic composition analysis were combined to clarify the genesis of granular calcite in the lacustrine fine-grained sedimentary rocks of the Permian Lucaogou Formation in the Jimusar Sag,Junggar Basin.It is found that the granular calcite is distributed with laminated characteristics in fine-grained sedimentary rocks in tuffite zones(or the transitional zone between tuffite and micritic dolomite).Granular calcite has obvious cathodoluminesence band,and it can be divided into three stages.Stage-Ⅰ calcite,with non-luminesence,high content of Sr element,inclusions containing Cos,and homogenization temperature higher than 170℃,was directly formed from the volcanic-hydrothermal deposition.Stage-Ⅱ calcite,with bright yellow luminescence,high contents of Fe,Mn and Mg,enrichment of light rare earth elements(LREEs),and high homogenization temperature,was formed by recrystallization of calcareous edges from exhalative hydrothermal deposition.Stage-IlI calcite,with dark orange luminescence band,high contents of Mg,P,V and other elements,no obvious fractionation among LREEs,and low homogenization temperature,was originated from diagenetic transformation during burial.The granular calcite appears regularly in the vertical direction and its formation temperature decreases from the center to the margin of particles,providing direct evidences for volcanic-hydrothermal events during the deposition of the Lucaogou Formation.The volcanic-hydrothermal event was conducive to the enrichment of organic matters in fine-grained sedimentary rocks of the Lucaogrou Formation,and positive to the development of high-quality source rocks.The volcanic-hydrothermal sediments might generate intergranular pores/fractures during the evolution,creating conditions for the self-generation and self-storage of shale oil.

Devonian Frasnian-Famennian transitional event deposits of Guangxi, South China and their possible tsunami origin

A suite of event deposits, isochronous and interrelated in origin, occurs widely near the Frasnian- Famennian boundary in Guangxi, South China. It is mainly distributed in the facies areas of the platform-margin slope and inter-platform rift-trough. The rudstone or calcirudite occur in the Liujing section of Hengxian and Luoxiu and Baqi sections of Xiangzhou in the facies area of platform-margin slope. The turbidites are observed in the sections of Yangdi and Baisha of Guilin, Du'an of Debao, Nandong and Sanli of Wuxuan, Xiangtian, Ma'anshan of Xiangzhou, Nayi of Chongzuo, Yunpan of Shanglin in the facies area of inter-platform rift-trough. The massive homogenites occur in sections of Mangchang, Luofu and Road from Nandan to Tian'e and Ma'anshan etc in the facies area of inter-platform rift-trough. Herein event deposits can be correlated in stratohorizon to the turbidite in the bottom of the Lower triangularis Zone in Hony railroad cut of Belgium, Devils Gate of Nevada, USA, Atrous of Morocco, South Urals and Fore-Kolyma of northeastern Siberia of Russia, and erosional discontinuities and brecciation in the Frasnian-Famennian boundary in South Polish-Moravian shelf. The event deposits could be caused by a violent tsunami related to bolide impacts into ocean.

THE RECORD OF YOUNGER DRYAS EVENT IN EOLIAN SAND DEPOSIT IN QAIDAM BASIN

The Qaidam Basin is one of the main areas where the desert of the Qinghai-Xizang Plateau is distributed.According to the envirotunment records and the age of stratigraphy in Xiaxitai section in southeast part of Qaidam Basin,this paper reached the following conclusions: the desert development, formation of the cold-dry climate, evolution of natural environment and their reverse changes occurred frequently since the late glacial. In eolian sand deposits, the YoungerDryas event clearly appeared, which manifesed a dry-cold climatic period. Now there are two different opinions about theclimatic effect of Younger Dryas. According to the predecessors’ research and the field work of the authors, it is considered that the Younger Dryas event not only exists in different climatic zones of China, but the manifests the unitary drycold climatic effect.

鄂尔多斯盆地二叠系盒8段河流扇沉积模式及勘探意义

根据野外露头及岩心的分析化验资料,在源-汇系统分析的基础上,对鄂尔多斯盆地二叠系盒8段的古气候环境及沉积相特征进行了详细研究。研究结果表明:(1)鄂尔多斯盆地二叠系盒8段Sr/Cu的值多大于10,V/Cr值多小于2.0,地层厚度差小于30 m,未出现明显的突变,古沉积坡度为0.5°~1.0°,古地貌开阔平缓且无明显坡折带,沉积水体较浅,是在古气候干旱、古地形平缓的背景下,受阶段性洪水作用主导的事件沉积。(2)盒8段沉积期,盆地不存在大面积汇水区,沉积体系中河流并未进入湖泊水体,而是向东南流出盆地或是消失在内陆干旱地区,全盆地以洪泛平原沉积为主,表现为河道与泛滥平原交互分布的沉积格局,形成了河流扇沉积模式。(3)湖水进退往复,洪水期与枯水期间歇发育,洪水期多期次决口河道接力搬运使得粗粒级砂岩向湖盆长距离延伸,枯水期发育厚层泥质沉积可作为区域性盖层,形成了良好的储盖组合,勘探潜力大。

全球锂铍铌钽矿产资源勘探开发新进展

这是一篇矿业工程领域的论文。锂铍铌钽,既是重要紧缺性稀有金属,也是新兴战略性产业的关键矿产,在成矿规律和勘探开发领域既有共性也有个性并有新的发展。本文力求尽量全面和准确地衡量和评价锂铍铌钽全球资源量和储量数据,及时反映勘探开发新形势和技术新进展。花岗伟晶岩多旋回成矿理论获得重要勘探突破,南美盐湖锂矿技术产量双释放临近,粘土岩和地热卤水提锂增储潜力巨大,碱性-过碱性火山成因-伟晶岩侵入型铌钽成矿在美洲和青藏地区研究深入,中国锂铍矿勘探获重大系列突破,鄂西北铌钽稀土等资源基地建设或可借鉴北美Nechalacho铌钽稀土矿床的勘探和开发经验。本文基于锂铍铌钽矿床和典型案例剖析,提出多期热事件多旋回岩浆分异出熔可能是大型-特大型矿床的关键条件。

湖泊沉积的灾害事件记录与识别方法:研究进展与存在问题

湖泊沉积储存有丰富的信息,常被用于指示气候变化。地震、洪水、滑坡或崩塌等自然灾害事件通常会在湖泊沉积中形成特征性的湖泊沉积扰动,可以使用湖泊地质学方法对其进行分析与识别。本文回顾了湖泊沉积研究历程,对典型自然灾害湖泊沉积特征进行系统总结,着重梳理介绍湖泊沉积中自然灾害事件识别方法。其中综合分析法集成了现阶段湖泊事件沉积识别的多种分析手段:(1)根据沉积相与异常事件沉积(EID)之间的关系判定其内源或外源成因;(2)根据对触发因素的排除,确定最可能的触发因素;(3)根据现有的识别标准,验证最可能触发因素的正确性。是目前识别湖泊扰动成因最有效的分析手段。本文还对湖泊沉积灾害事件研究的优势与不足及制约因素进行讨论,湖泊沉积具有连续性、敏感性和高分辨率的特点有助于对灾害事件进行研究,但对湖泊典型自然灾害事件沉积识别标志的建立仍然是制约湖泊异常事件沉积研究的关键。

华北克拉通古元古代条带状铁建造同位素年代学研究进展

世界超大型富铁矿床多为前寒武纪条带状铁建造(BIF)。其中,70%以上的铁形成于成铁纪(2.5~2.3Ga),规模超过10^(5)Gt的铁建造也主要形成于成铁纪,且为Superior型。然而,华北克拉通BIF总体被视为太古宙(>2.5Ga)Algoma型,缺乏成铁纪甚至古元古代Superior型BIF。本文系统搜集和分析了华北克拉通BIF的锆石年龄数据,初步确定太华群铁山庙组、荡泽河群铁山岭组、济宁群颜店组、五台群金岗库组、文溪组、柏枝岩组、大青山地区表壳岩系中的BIF形成于成铁纪;粉子山群小宋组、霍邱群吴集组、周集组中的BIF年龄数据跨越了成铁纪-层侵纪界线,但可能属成铁纪;吕梁群袁家村组、水底沟群孔兹岩系中的BIF形成于层侵纪;嵩山群五指岭组、阜平湾子群中BIF形成于造山纪。五台群中BIF属于Algoma型,其他属于Superior型。古元古代早期,生命活动和生物光合作用显著增强,海洋整体由还原向氧化状态过渡,导致大量Fe(Ⅱ)被氧化为Fe(Ⅲ),全球BIF爆发式沉积。华北克拉通BIF赋矿地层碎屑锆石记录了2.99~2.94Ga、2.76Ga、2.54Ga三次主要的岩浆活动及陆壳增生事件,以2.54Ga岩浆活动最强烈。华北克拉通新太古代末期及古元古代早期稳定性较差,不利于大规模克拉通盆地形成,造成了华北克拉通成铁纪BIF铁矿规模小、品位低。

Volcanic Event Layers——A Marker Bed of Correlation of Coal Measures

Upper Carboniferous-Lower Permian volcanic event deposits from two cross sections in Nanpiao, Liaoning Province, and the Daqing Mountains, Inner Mongolia, were examined by systematic rock and mineral identification, differential thermal analysis, X-ray diffraction, scanning electron microscopy and trace element and rare earth element quantitative analysis. According to the results, twelve sequences of volcanic event deposits have been distinguished from bottom to top, including 34–39 volcanic event layers. As these layers each have their own distinctive petrological, mineralogical and geochemical characteristics and were derived from the same source, they provide new evidence for further ascertaining the distribution characteristics of volcanic event deposits on the northern margin of the North China plate and carrying out the stratigraphic correlation using volcanic event layers as marker beds.

华北克拉通古元古代石墨矿成因研究进展与问题

华北克拉通周缘发育有三条古元古代石墨成矿带,包括东部石墨成矿带(胶-辽-吉造山带)、西部石墨成矿带和南部石墨成矿带。这些石墨矿床占全国储量的74%,是我国晶质石墨矿床的重要产地。本文在广泛收集和分析该地区以往石墨矿床研究成果的基础上,对华北克拉通周缘古元古代石墨矿床的分布规律、成因机制、形成时代,及其对地球早期环境演化的启示进行了系统归纳总结,并对存在的关键问题进行了探讨和展望。华北克拉通东部石墨成矿带从北到南石墨矿体主要产出在吉南地区的集安群、辽东地区的辽河群以及胶北地区的荆山群中;西部石墨成矿带中的石墨矿床主要赋存于乌拉山岩群和集宁群中;南部石墨成矿带中的石墨矿则主要出露于华北克拉通南缘太华岩群中。华北克拉通三条石墨成矿带中的石墨矿床具有一定的相似性,都属于区域变质型石墨矿床,含矿岩石都是变质表壳岩,包括含石墨斜长片麻岩、含石墨长英质片麻岩、含石墨透辉麻粒岩、含石墨大理岩等。石墨形态多以鳞片状为主,石墨碳质主要来源于有机物,局部混合有少量的无机碳。这三条石墨成矿带中的含矿岩石具有相似的沉积时代(2.0~2.2Ga)和变质成矿时代(1.8~1.95Ga)。华北克拉通周缘这些古元古代巨量石墨矿床的形成是古元古代生命繁盛的最有力证据,对地球早期环境演化具有重要影响:一方面,有机物的大量埋藏可以导致大气氧含量的升高以及碳酸盐碳同位素正向偏移;另一方面,这些埋藏的有机物在后期俯冲碰撞造山过程中将发生变质脱碳作用,消耗氧气并释放富集轻碳同位素^(12)C的CO_(2),这一过程可能会导致大气氧含量降低以及碳酸盐碳同位素值负向偏移。然而,古元古代巨量有机物的埋藏以及在后期碰撞造山剥蚀风化过程中对地球早期大气的影响具体有多大,还需要我们更多的地质数据来对其进行定量估算。华北克拉通周缘这些形成于古元古代的石墨矿床记录了有机物从埋藏到变质形成石墨的完整过程,是研究这些问题的理想对象,对于我们理解地球早期环境演化过程具有重要的意义。

Simulation of temporal characteristics of ion-velocity susceptibility to single event upset effect

Using a Monte Carlo simulation tool of the multi-functional package for SEEs Analysis （MUFPSA）, we study the temporal characteristics of ion-velocity susceptibility to the single event upset （SEU） effect, including the deposited energy, traversed time within the device, and profile of the current pulse. The results show that the averaged dposited energy decreases with the increase of the ion-velocity, and incident ions of 2~9Bi have a wider distribution of energy deposition than 132Xe at the same ion-velocity. Additionally, the traversed time presents an obvious decreasing trend with the increase of ion-velocity. Concurrently, ion-velocity certainly has an influence on the current pulse and then it presents a particular regularity. The detailed discussion is conducted to estimate the relevant linear energy transfer （LET） of incident ions and the SEU cross section of the testing device from experiment and simulation and to critically consider the metric of LET.

Thermoluminescence Dating of Colluvial Deposits and Its Application to Chronological Study of Paleoearthquakes

On the basis of studies of lithofacies features of colluvial deposits, applicability of thermoluminescence dating of the colluvial deposits at different lithofacies positions, and reliability of the dating result, the thermoluminescent ages of colluvial deposit from different types of faults were determined. From the above, the ages of paleoseismic events and their recurrence intervals on the related fault were deduced.

多期构造变形事件对吉林南部大横路Cu-Co矿床富集成矿的制约

钴矿是重要的战略性金属矿产资源之一,对其成矿作用(如构造与成矿的关系)进行深入的研究能为前期指导找矿提供理论依据。本文对中国东部吉林白山市三道沟镇三岔河村大横路Cu-Co矿开展了相关工作,包括野外构造解析、钻孔-岩芯资料分析、钻孔薄片综合矿物分析系统(TIMA)实验和区域相关岩石年代学等。构造解析显示大横路Cu-Co矿围岩变形包括层片交切、S_(1)面理和褶劈理等构造要素。钻孔-岩芯资料分析矿区发育大量F_(2)紧闭褶皱、逆冲断层及断层相关褶皱、倒转褶皱F_(2)等。钻孔、探槽薄片样品TIMA实验显示含Co流体大量富集于低角度逆冲断裂、倒转褶皱韧性剪切域和断层相关褶皱转折端处。这些工作显示走向为NE的低角度逆冲断裂及断层相关褶皱对大横路Cu-Co矿的富集起到关键的控制作用。相关年代学工作,结合前人研究及大量区域地质资料表明:(1)矿区内逆冲断层及褶皱等控矿构造要素为古元古代构造事件的产物;(2)中生代构造事件对成矿作用的制约(Cu-Co矿的再富集)可能来自于白垩纪大规模的伸展作用。

鄂尔多斯盆地西南部三叠系延长组长9段事件沉积类型、特征及地质意义

通过岩心观察、薄片鉴定、测井及测试数据分析,对鄂尔多斯盆地三叠系延长组9段(简称长9段)事件沉积类型及特征进行剖析。研究表明,盆地西南部长9段存在地震、重力流、火山、缺氧等4类9亚类事件沉积。通过对不同类型事件沉积特征和分布规律分析,提出不同类型的事件沉积普遍存在共生或伴生关系,具有内在成因联系和分布规律。识别出事件沉积较发育的5种沉积(微)相,建立了事件沉积成因模式。震积岩主要发育在盆地幕式扩张的湖侵期,常见液化流动、重力作用及脆性剪切变形;重力流主要分布在高水位期,夹于前三角洲或半深湖细粒沉积中,形成条带状、朵状的滑塌浊积扇,震积岩层段之上相对发育;火山事件沉积见于长9段下部,呈顶、底突变接触,可反映同期火山活动;缺氧沉积一般形成于湖侵后期至高水位期。长9段高位期发育厚层富有机质泥页岩,沉积期事件沉积有利于形成油气潜在储集层。

干旱湖盆边缘浅水三角洲沉积特征与沉积模式——以青海尕斯库勒油田下油砂山组Ⅵ油组为例

综合利用岩心、测井及现代沉积资料,采用比较沉积学方法在青海尕斯库勒油田下油砂山组识别出典型的干旱湖盆浅水三角洲成因储层,在此基础上,通过现代沉积与地下储层密井网解剖初步建立了干旱湖盆浅水三角洲沉积模式。研究表明:干热气候引起的沉积物性质与水文特征差异,导致干旱浅水三角洲存在明显的事件性特征且沉积特征明显有别于湿润气候下的浅水三角洲,其前缘暴露时间长、暴露区域广,泥质沉积物以红褐色为主,缺乏植物化石。干旱浅水三角洲的基本沉积单元为一条供给河道控制的复合沉积体。以一条主干分流河道为骨架,决口水道—朵体与分流水道—河口坝组合分别高频发育于河道主干河道侧缘和末端,但其规模较小。干旱浅水三角洲存在明显的顺源相带差异,按照沉积特征可将这类三角洲分为平原、前缘及前三角洲;在平原亚相,主干河道切入平原沉积并在边缘发育多个决口朵体,朵体内部可见发散状决口水道;进入前缘亚相后,主干河道分支成多条分流河道,每一条分支河道控制形成一个河坝组合,最终形成多个辐射状延伸、侧向彼此独立的河坝组合;河坝组合一般呈“河在坝上走”的样式,其内部发育多条末端分流水道,整体呈底平顶凸的半透镜状,河道位于河坝组合中部;前三角洲主要沉积泥岩,缺乏河流供给,缺少砂质沉积。主干河道和河坝组合为该类三角洲的优质储集体。

湖相细粒沉积岩中晶粒方解石成因及其对火山-热液活动的指示——以吉木萨尔凹陷二叠系芦草沟组为例

以准噶尔盆地吉木萨尔凹陷二叠系芦草沟组细粒沉积岩中晶粒方解石为研究对象,综合运用岩心观察、薄片观察、阴极发光分析、流体包裹体测试、扫描电镜、同位素组成分析等手段,对湖相细粒沉积岩中自生矿物的成因开展研究。结果表明:晶粒方解石呈层状分布于沉凝灰岩发育层段或沉凝灰岩与泥晶白云岩过渡层段的细粒沉积物中,方解石具有明显的阴极发光环带,可分为3期:Ⅰ期方解石不发光,含有较高的Sr元素,包裹体中包含羰基硫成分,均一温度超过170℃,由火山-热液喷流物质沉积形成;Ⅱ期方解石呈亮黄色光,含有较高的Fe、Mn、Mg元素,轻稀土元素富集,包裹体均一温度高,为热液喷流的钙质环边重结晶形成;Ⅲ期方解石呈暗橙色发光的环带,含有较高的Mg、P、V等元素,稀土元素无明显分异,包裹体均一温度低,为埋藏过程中成岩转化形成。晶粒方解石在垂向上规律性出现,并且其形成温度由颗粒中心向边缘降低,为芦草沟组沉积时期的火山-热液活动提供了直接证据。沉积期火山-热液活动有利于芦草沟组细粒沉积岩中的有机质富集,对优质烃源岩发育有正面效应,并且火山-热液喷流物质在演化过程中易形成晶间孔缝,为页岩油自生自储创造了条件。

江苏徐州赵圩剖面新元古界倪园组沉积环境演化与事件沉积

江苏徐州赵圩剖面新元古界倪园组出露完整连续,岩性组合极具代表性,沉积现象丰富,发育有大量典型的事件沉积,因其成因存在争议而长期受到关注。本研究以倪园组野外宏观岩性组合及镜下微观岩石特征为基础,依据宏观—微观对照的方法,分析了倪园组沉积环境及事件沉积特征,探讨了事件沉积频发及类型多样的成因。研究表明:(1)倪园组沉积环境自下而上依次为潟湖—缓坡中上部—缓坡中下部—缓坡中上部—潮坪+潟湖;(2)事件沉积在各段的发育情况均有所区别,其中砾屑灰岩与冲刷—充填构造在各段均有发育,但下段与中段规模较大,除此之外,中段局部见震裂角砾岩、液化底辟构造,顶部发育臼齿构造,而上段底部以臼齿构造为主,中上部见软沉积物变形构造以及交错层理,结合沉积环境分析,认为事件沉积主要发生于缓斜坡环境以及潮坪、潟湖环境;(3)综合以上研究结果,认为倪园组频发—多类型事件沉积与正常沉积构成的特殊旋回,其动力机制或与周期性的地震—风暴作用有关,即可能为Rodinia古大陆的汇聚—裂解导致的华北地台东缘伸展型区域构造运动与米兰科维奇旋回的叠加而引发的多因素耦合作用的结果。

鄂尔多斯盆地西、南缘奥陶纪地质事件群耦合作用

北祁连造山带和北秦岭造山带在早古生代经历了相似的洋陆转化过程,于奥陶纪时发育了汇聚板块边缘的沟-弧-盆体系,分别形成了北西向展布的北祁连造山带走廊南山北缘早古生代岛弧及弧后盆地和东西向展布的北秦岭造山带早古生代岛弧及弧后盆地。期间,秦岭-祁连洋的俯冲造山作用和鄂尔多斯盆地西南缘沉积类型和内陆湖盆的发展演化之间存在有机的联系,构成了盆-山耦合体系,引发一系列构造事件、火山喷发事件和多种类型的事件沉积等。它们之间存在着一系列成因机制上的联系,有着共同的宏观背景。鄂尔多斯盆地西、南缘在几乎相同时期存在一次构造背景的转变,由被动大陆边缘转化为主动大陆边缘,并诱发了多期火山喷发事件,在盆地西南缘奥陶系形成多套斑脱岩夹层,这些斑脱岩可能为同时期或者稍后的钾盐矿(包括含钾卤水)的形成提供了重要物源。同时,鄂尔多斯盆地南缘由浅水碳酸盐台地陷落为深水斜坡,在盆地西、南缘奥陶系有规律的集中发育重力流沉积(海底扇、浊积岩等)、滑塌沉积和震积岩等事件沉积。从形成机制上,华南板块向北俯冲触发了火山活动和地震,火山喷发在奥陶系集中沉积了多套凝灰岩夹层,地震活动导致同时期大套重力流沉积,并触发相对深水区沉积物向深水区移动,使得重力流沉积转化为浊流沉积,形成了具有良好储层的浊积岩。统计表明,上述事件发育的时间与秦岭地区构造活动相对最活跃的时期基本一致。因此这些分布稳定的凝灰岩薄层和中奥陶世集中有规律分布的重力流沉积砂体为华南板块向华北本快俯冲背景下形成的,它们之间存在耦合关系。

济阳坳陷早第三纪震积岩的发现及其意义

济阳坳陷下第三系沙河街组三段及四段地层中发现了大量与地震活动有关的变形构造 ,如微断层、层内小褶皱、液化砂岩脉、振动液化卷曲变形和火焰构造等。通过牛1 1 0、利 981、车古 2 0 1和义 3 7 7等井的系统观察 ,发现震积岩的垂向序列自下而上依次为震裂岩和震塌岩层段、阶梯状正断层层段、振动卷曲变形层段、液化砂岩脉层段、碎块层段和均一层段 ,分别对应于强震期、地震衰减期和余震期。震积岩的发现不但有助于分析判断控盆边界断裂的强烈活动时期 ,震积岩自身也可能是一种潜在的油气储集体 ,因而地震事件沉积具有重要的研究意义。