东南极北查尔斯王子山新生代Pagodroma群生物地层特征

东南极北查尔斯王子山Pagodroma群沉积物是冰海沉积作用的产物。Pagodroma群中发现的原位硅藻化石组合及软体动物、有孔虫等化石,可直接用于生物地层定年。Pagodroma群的4个地质单元:Mount Johnston组、Fisher Bench组、Battye Glacier组和Bardin Bluffs组的地质年代分别为晚渐新世—早中新世、中中新世、中—晚中新世和上新世—早更新世。根据生物地层特征,东南极中—晚中新世仍适宜植物生长,但气候条件相当恶劣。综合分析表明东南极中新世—上新世存在几个暖期,冰盖有几次大的波动,支持动态论观点。     

伊朗中伊朗盆地库姆组地层的时代

对伊朗中伊朗盆地卡尚地区库姆组的微体化石样品分析 ,不仅发现了新的有孔虫和介形虫化石组合 ,而且还首次发现了较丰富的钙质超微及少量的沟鞭藻化石。依据这些化石的组合面貌 ,认为库姆组含始新世地层无疑 ,修正了以往认为库姆组地层时代为中—晚渐新世至早中新世的观点。     

南海北部琼东南盆地BD19-2-2井中新世钙质超微生物地层及沉积环境

对南海北部琼东南盆地BD19-2-2井中新世地层中的钙质超微进行了定量和半定量分析,发现井段上部1800~2550m地层化石较丰富,而下部2574~3100m化石丰度及分异度明显降低;根据钙质超微化石标志种的存在,对该井的生物地层进行了划分,在1800~3100m井段地层中识别出9个钙质超微化石带或联合化石带,地层时代为早中新世至晚中新世,同时探讨了钙质超微划分下中新统-中中新统、中中新统-上中新统界线的化石标志。依据钙质超微化石总丰度、分异度及特征性环境指示种丰度的逐渐变化,确认BD19-2-2井从早中新世至晚中新世经历了4个沉积环境演化阶段,海水深度由浅变深,海水变暖。     

安徽萧县白土剖面有孔虫动物群研究

实测描绘了安徽萧县白土镇石炭纪—早二叠世的地层剖面,对剖面中采集的样品进行了磨片,并在偏光显微镜下对磨片进行了系统鉴定,共鉴定出9科16属34种,且进行了系统的描述。建立了有孔虫化石组合带Tetratax-is-Nodosaria-Palaeotextularia组合带,为晚石炭世晚期(C22)。将研究区内的有孔虫化石组合带与国内不同地区有孔虫化石组合带进行了对比,探讨了石炭纪—早二叠世有孔虫化石在地层中的分布特征,探讨了有孔虫化石对地层划分对比中的作用,认为有孔虫化石对于石炭—二叠纪的地层界线也有重要的意义。     

新疆库车盆地吉迪克组的地层时代和沉积环境

库盆地吉迪组分布十分广泛,它是储油层和油、气田的盖层,主要由碎屑岩或碎屑岩与石膏岩的互层组成,沉积厚度301.4-1081m。这套地层中富含有孔虫、介形类、抱粉、轮藻和腹足类等化石,通过古生物群的分折研究,可确定其沉积时代为中新世,更确切地说为中新世早、中期。通过沉积物特征和古生物群中广海、底栖有孔虫,咸水型介形类,水生植物抱粉和沟鞭藻等门类的分析,大致可确定沉积物的物源主要来自盆地北部的南天山山脉。沉积物颗粒自北向南由粗变细,水体中的含盐度自西向东逐渐升高,沉积了石膏、石盐和钙芒硝等盐类物质;推测在中新世早、中期库车盆地可能与塔里木盆地西部的喀什-乌恰-带残留海相连通。     

山东淄博太原组有孔虫及石炭系与二叠系界线

通过对山东省淄博地区太原组小有孔虫类动物群的系统研究,共鉴定出小有孔虫11属22种及部分未定种。根据有孔 虫类化石在地层中的分布和垂向变化规律,建立了两个小有孔虫化石组合带：IBradyina-Plectogyra 组合与IITetrataxisNodosaria-Palaeotextularia 组合。通过与邻区及华中华北其它地区的有孔虫进行对比,并结合前人对本区 类化石的研究结 果,确定了各组合带的地质时代：太原组小有孔虫动物群第I组合带地质时代归为晚石炭世,第II组合带地质时代归为早二 叠世,其层位相当于山东地区太原组 类Pseudoschwagerina带之底。     

对藏北嘎色地区沙木罗组的新认识

笔者在西藏班公错-怒江结合带中段南缘嘎色地区的一套缺少化石依据的地层中,发现有孔虫Mesorbitolinasp.等化石,地层时代确定为晚侏罗世—早白垩世,层位应归属沙木罗组上部。该套地层地质时代的确定,对研究沙木罗组的沉积相,重塑古地理环境有十分重要意义。     

我国东部第四纪的海陆过渡相地层

第四纪期间我国海区的海面升降,以及东部沿海第四纪海侵的研究,近年来已经引起地质工作者的广泛注意。有孔虫、介形虫、孢粉等微体化石的运用,在海侵研究中起着十分重要的作用。然而,在寻找海侵地层的过程中也出现了一种值得注意的倾向,那就是把凡是找到一点海相化石(如有孔虫)的地层,统统叫做海相层,一概划在海岸线之外。     

中国西部晚第三—第四纪有孔虫和钙质超微化石的发现及其地…

报导了中国西北晚中新世－第四纪陆相咸化湖泊介形类群中发现的有孔虫和钙质超微化石组合，并从生态和古地理的角度论证了它们属于非海侵来源，图示了这些生物化石的地理分布。认为主要受到干燥气候下咸化湖泊环境的控制，中新世以来，喜盐水水生生物九介形类，有孔虫和钙质超微生物等随干旱气候控制的咸化湖不断向东扩展。因此，不能笼弘地把这些生物化石作为海侵证据根据地质学现实主义类比原则，提出中国东剖 第三纪没有在大     

地质年代简介

地质年代学是研究由古生物化石和岩石、矿物记录地壳物质产生、发展及演变历史的一门学科.十九世纪中叶以前,地质工作者一直把距今约6亿年,已发现有化石的地层叫显生宙;而显生宙以前,当时没有发现化石的地层叫隐生宙.显生宙又划分为古生代、中生代和新生代.近十多年来,由于对前枣武纪地     

Nearshore to offshore facies and depositional history of the Ordovician Daylesford Limestone New South Wales

The Daylesford Limestone is the basal formation of the Ordovician Bowan Park Group of central western New South Wales. The formation contains four main limestone types and minor intercalated terrigenous beds. Limestones are: (1) grain‐stone, (2) grey skeletal wackestone and packstone, (3) dark grey burrowed wackestone and packstone, and (4) dark grey burrowed lime mudstone. Grainstone and grey skeletal wackstone and packstone are dominant in eastern sections; they are laterally equivalent to, and interfinger with, dark grey muddy limestones that dominate western sections. Lithoclasts are abundant in the grainstone but are absent from muddy sections to the west except in thin beds above disconformities. The rock types of the Daylesford Limestone also tend to occur sequentially above some disconformities; the full sequence is: grainstone (or grey skeletal wackestone and packstone) grading up into dark grey burrowed wackestone and packstone and thence into dark grey burrowed lime mudstone. Each sequence is probably trans‐gressive and reflects deepening water.

During deposition of the Daylesford Limestone, an area to the east was uplifted, providing lithoclasts to be reworked into the neighbouring depositional basin. Uplift also produced numerous regressions and subaerial disconformities. Facies patterns were essentially similar throughout the history of the formation. Grainstone accumulated in high‐energy nearshore environments adjacent to the uplifted area, and grey skeletal wackestone and packstone in low‐energy nearshore environments. Dark grey lime mudstone formed in offshore low‐energy environments to the west of the uplifted area; and dark grey wackestone and packstone in intermediate environments. In parts, burrowing organisms kept pace with sedimentation and locally mixed interbedded grainstone and muddy limestone.     

元古界会理群凤山营组风暴流沉积特征

四川省会理县洪川桥地区,是会理群凤山营组广泛分布地区之一,出露面积达百余平方公里。在洪川桥凤山营组剖面的上部(洪剖119层—108层),发育一套约845m厚的风暴流沉积。现将其特征及形成机制作一初步分析,以供参考。一、岩性特征风暴流沉积物,主要为灰—深灰色粉砂质粉屑灰岩和部分泥质灰岩。有时两者呈薄的互层出现。一般层厚几毫米到几厘米,沿走向在数十厘米或几米内尖灭,形成一个个薄的透镜     

广西南宁地区泥盆系硅质岩地球化学特征及沉积环境

泥盆纪时,广西南宁附近发育了一套从早泥盆世埃姆斯期到晚泥盆世弗拉斯期末的硅质岩建造,硅质岩多为薄层,灰黑到黑色,至弗拉斯阶上部变为灰黄色,水平纹理发育,常夹火山凝灰岩或与之互层。这套硅质岩SiO2含量高（一般>90％）,其他主量化学成分均很低（一般<5%）。TFe2O3和含量相对比较富集（平均含量3.32％）, Al2O3、TiO2、MgO和MnO相对贫乏（平均含量分别为0.71％、0.04％、0.10％和0.02％）。常量元素Fe/Ti、（Fe+Mn）/Ti和Al/（Al+Fe+Mn）比值的平均值分别为91.65,92.12和0.25,微量元素Ti/V和U/Th比值的平均值分别为4.57和4.09,其中U/Th比值在弗拉斯期早期达到最大。这些数据说明,硅质岩在形成时受到了明显的海底热液活动影响,而这种热液活动在弗拉斯期早期达到最强,后逐渐减弱,而热液活动的强度可能主要受盆地裂解（或张裂作用）的影响;因此,盆地拉张作用在弗拉斯期早期达到最强,这与硅质岩的空间分布是吻合的。     

长江三角洲地区晚第四纪年代地层框架及两次海侵问题的初步探讨*

根据对长江三角洲地区两个以细颗粒沉积为主的晚第四纪钻孔进行OSL测年、U系测年、孢粉分析和微体古生物分析,试图建立高分辨率气候地层,从而建立本区晚第四纪的年代地层框架,并探讨本区晚第四纪的标志层和期间发生的两次海侵及其机制。研究结果显示,两孔记录的古气候波动可与深海氧同位素曲线进行对比：对应于深海氧同位素曲线第6阶段（MIS 6）,堆积厚层的河道相粗颗粒沉积及第3硬土层,反映当时气候寒冷;第5阶段（MIS 5）,为滨海湖沼沉积,沉积物的颗粒显著变细;第4阶段（MIS 4）,本区形成第2硬土层;第3阶段（MIS 3）的早期,本区也发育滨海湖沼沉积,中晚期则形成潟湖—砂坝体系,在滨海平原区普遍发育粉、细砂层;第2阶段（MIS 2）,地层由下粗上细的沉积序列构成,下部为黄灰、棕黄色粉砂,上部则为棕黄色或暗绿色硬粘土。其中MIS 6、MIS 4和MIS 2期间发育的3层硬土层可作为本区晚第四纪沉积的标志层。在MIS 5和MIS 3期间,本区均发生海侵,MIS 5时期由于古地势较高、淡水径流和陆源物质输入丰富,因此海水影响微弱;MIS 3时期的中晚期为缺乏淡水输入的潟湖—砂坝环境,从而形成广泛的海侵层。     

西藏北部班戈地层分区下白垩统郎山组、康曲组和余穷组地层层序研究

在西藏自治区北部区域地质调查过程中 ,在班戈地层分区的下白垩统郎山组之上发现一套厚约 180 0 m的滨海—浅海相碳酸盐岩、陆源细碎屑岩岩石组合 ,该套组合不属于郎山组定义之内 ,且出露良好、层序稳定、标志清楚、厚度巨大、化石丰富 ,并具有很强的可填图性。因此 ,我们将整合于郎山组之上 ,岩性以杂色微—薄层状钙质泥岩、钙质 (粉 )砂岩与泥质生物灰岩的韵律产出为特征 ,产圆笠虫、腹足类、双壳类等化石的地层命名为康曲组 ;将整合于康曲组之上 ,下部以灰—深灰色中薄层状泥质生物灰岩、圆笠虫泥晶灰岩、钙质泥岩等韵律出现为特征 ,上部以灰色中—厚层状含硅质结核圆笠虫泥晶灰岩、圆笠虫泥晶灰岩夹灰绿色薄层状钙质砂岩为特征 ,富含圆笠虫、腕足类、腹足类、双壳类及海胆等化石的地层定名为余穷组。时代均置于早白垩世晚期     

重庆北碚河西洞上三叠统须家河组一段上部剖面沉积相分析

对重庆北碚上三叠统须家河组一段地层特征、岩性特征、沉积相及演化规律进行了系统研究。研究区须一段以灰色、褐灰色细砂岩及深灰色、灰黑色页岩、粉砂质泥（页）岩夹薄煤层为主,见炭化植物碎片及菱铁矿结核,砂岩类型主要为长石岩屑石英砂岩及长石岩屑砂岩,大型槽状交错层理、平行层理、水平层理及沙纹层理发育。综合分析认为研究区须一段属浅水三角洲沉积环境,包括三角洲平原、三角洲前缘和前三角洲3种亚相,可进一步划分出水上（水下）分支河道、沼泽、支流间湾、河口砂坝等沉积微相。其垂向序列反映了沉积环境三角洲平原-三角洲前缘-前三角洲-三角洲平原的演化过程。     

Mid-Paleocene event at Gabal Nezzazat,Sinai, Egypt: planktonic foraminiferal biostratigraphy,mineralogy and geochemistry

The Qreiya Beds that record the ‘mid-Paleocene event’ at Gabal Nezzazat occur within the Igorina albeari (P3b) Zone and constitute part of a 14-m thick shale succession that ranges in age from Early to Late Paleocene. They are composed of four alternating dark grey and brown shale beds, which are thinly laminated, phosphatic, organic-rich and extremely sulphidic. They are characterized by distinct enrichment and high peak anomalies in chalcophiles (Zn, Co, Ni, Cu and Pb) and organic association elements (V and Cr), especially within the brown organic-rich beds. It is concluded that these elements are incorporated into the phosphatic debris, sulphides and organic matter. In contrast, the grey beds are enriched in clay minerals and quartz. Clay mineral assemblages indicate alternating periods of warm/humid climate (high kaolinite) and dry climate (low kaolinite) during the formation of the grey and brown beds, respectively. The sediments of the Qreiya Beds yield lithological, biotic, geochemical and mineralogical data indicative of suboxic/anoxic marine environments as a result of high productivity and/or upwelling. The top metre of the succession below the Qreiya Beds is characterized by a progressive change from faunas dominated by praemurcurids to faunas dominated by Morozovilids, and by a progressive upward decrease in δ¹³C_carb and δ¹⁸O_carb values. The foraminiferal faunal change may reflect shallowing and warming preceding deposition of the Qreiya Beds. The change in isotopic values is inferred to be the result of surface weathering, fluvial input and diagenesis with no evidence of any primary change that could support presence of a hyperthermal event.     

Turbiditic,clay‐rich event beds in fjord‐marine deposits caused by landslides in emerging clay deposits – palaeoenvironmental interpretation and role for submarine mass‐wasting

Distinct, clay‐rich beds are common in fjord‐marine deposits in Trondheimsfjorden near the outlet of the Nidelva River. Their characteristic light‐grey colour makes the beds easily distinguishable from the surrounding brownish, bioturbated, muddy fjord sediments. The clay‐rich beds commonly display a clear stratification in clay, silt and very fine sand. The beds are interpreted as originating primarily from large quick‐clay landslides upstream along the Nidelva River. Such events resulted in a sudden increase in the supply of fines to the fjord from disintegrating landslide debris and heavily loaded effluent plumes, possibly favouring hyperpycnal flow. Typical beds can be divided into a clay‐rich lower section, reflecting an initial surge with high concentrations of suspended mud, and a sandier upper section reflecting pulses of higher energy. This development can be explained, for example, by a lowering in the supply of mud, an increasing activity of deltaic sediment gravity flows due to a higher availability of sandy sediments in the landslide‐affected river, and by flooding and/or breaching of landslide dams. The typical, stratified beds are interpreted as the result of one quick‐clay landslide, whereas exceptionally thick, less organized, stratified beds are possibly the result of several large and/or complex landslides. Radiocarbon dating of mollusc shells has helped to establish a chronology for major terrestrial landslides in the area. The frequency of landslides increases towards the end of the Holocene. This is explained by a progressively deeper incision of rivers during glacioisostatic rebound, possibly combined with a change to a wetter climate. The marine core record displays deformation structures and hiati representing submarine mass‐wasting events, and supports the evidence that the clay‐rich beds are weak layers in the fjord‐marine stratigraphy. The inherent weakness of these layers may be explained by their composition, immature texture, loose fabric and contrasting permeabilities in the deposits. Slide‐prone layers similar to the clay‐rich beds described here may be found in other comparable fjord‐marginal settings and are considered to be of importance for geohazard assessments.     

湖南保靖地区震旦系陡山沱组页岩气成藏地质条件分析

为评价湖南保靖地区震旦系陡山沱组页岩气勘探潜力,利用野外地质调查及页岩气井勘探成果资料,结合钻井岩心样品测试结果,研究了湖南保靖地区陡山沱组页岩储层发育的特征及其分布规律。湖南保靖震旦系陡山沱组发育被动大陆边缘浅水陆棚斜坡相灰色白云质灰岩、黑色碳质泥岩、黑色硅质岩、黑色硅质岩、深灰色泥晶灰岩、深灰色含钙碳质泥岩等。该页岩层分布稳定,厚度巨大(150～200m);有机碳含量较高(4.07%～10.25%),热演化程度较高(3.78%～4.97%),达到过成熟阶段;页岩孔隙度中等(0.19%～2.355%),渗透率极低(0.0005257～0.5910081 mD);脆性矿物含量较高(55.9%～84.5%),主要以石英、方解石、黄铁矿、斜长石为主;黏土矿物含量较低(16.5%～44.1%),以伊利石和伊蒙混层为主,经历了晚成岩作用阶段;储集空间主要有矿物溶蚀孔、有机质溶蚀孔、黄铁矿晶间孔、黏土矿物晶间孔、成岩解理缝及构造微裂缝等。综合研究分析认为,湖南保靖地区陡山沱组具有较好的页岩气成藏条件,可继续加大勘探力度。     

The role of wave reworking on the architecture of storm sandstone facies, Bell Island Group (Lower Ordovician), eastern Newfoundland

Stacked shallow marine cycles in the Lower Ordovician, Bell Island Group, of Bell Island, Newfoundland, show upward thickening and upward coarsening sequences which were deposited on a storm-affected shelf. In the Beach Formation each cycle has a facies sequence comprised, from base to top, of dark grey mudstones, light grey mudstones, tabular sandstones and mudstones, lenticular sandstones and mudstones, and thick bedded lenticular sandstones, reflecting a progressive increase of wave orbital velocities at the sediment surface. The mudstones and tabular sandstones reflect an environment in which the sea floor lay in the lower part of the wave orbital velocity field and in which tempestites were deposited as widespread sheets from weak combined flow currents. The lenticular sandstones in the succeeding facies are wave reworked sands, commonly lying in erosional hollows and having erosional tops and internal hummocky cross-stratification. Planar lamination is relatively uncommon and sole marks are mainly absent. In this facies oscillatory currents were dominant and accumulated sand in patches generally 10–30 m in diameter. The facies formed on the inner shelf where the oscillatory currents generated by storm waves had powerful erosional effects and also determined the depositional bedforms. Mud partings and second-order set boundaries within sandstone beds are believed to separate the products of individual storms so that many lenticular sandstone beds represent the amalgamation of several event beds. This interpretation has important implications for attempts to estimate event frequency by counting sandstone beds within a sequence and for estimates of sand budgets during storm events. The thick bedded lenticular facies appears to have been formed by erosion of the mud beds between the lenticular sands, leading to nearly complete amalgamation of several lenticular sand bodies except for residual mud partings. In the overlying Redmans Formation the process of amalgamation progressed even further so that nearly all the mud partings were removed, resulting in the formation of thick bedded tabular sandstones. Sequence stratigraphic analysis of the cyclical sequence suggests that the cycles were eustatically controlled. The rising limb of the sea level curve produced only the dark grey mudstone part of the cycle while the remainder of the cycle was deposited on the falling limb. There is a gradational but rapid facies transition from the tabular to the lenticular sandstone facies which is interpreted as occurring at the inflexion point on the falling limb. The thick bedded facies of the Beach Formation and the thick bedded tabular facies of the Redmans Formation represent periods of maximum sea level fall. The stacked cycles in the Beach Formation are interpreted as an aggradational, high frequency sequence or parasequence set bounded at the top by a sequence boundary and succeeded by the three aggradational parasequences of the Redmans Formation. The recognition of storm facies with sandstone beds of very different bed length has important implications for the reservoir modelling of such facies.