查询词典 biostratigraphy

The Lower/Upper Cretaceous boundary in Songliao Basin is,therefore,between the Quantou and Denglouku formations,instead of between the Quantou and Qingshankou formations.2.The dark mudstones and shales in the Member 1 of Qingshankou Formation are of high organic carbon and low diasteranes contents.Organic geochemical characters are illustrated by biomarkers of 28,30-bisnorhopane and gammacerane,and positive excursion of kerogen isotopes.It is suggested that the dark mudstones and shales in the Member 1 of Qingshankou Formation are the products of lake anoxic period.It corresponds to the oceanic anoxic event at Cenomanian-Turonian boundary in Cretaceous.3.Based on the study of biostratigraphy,chronostratigraphy,magnetostratigraphy and event stratigraphy,a correlation of the lacustrine sequence to marine standard has been proposed,i.e.,the Quantou Formation corresponds to Cenomanian stage,Qingshankou Formation correlates to Later Cenomanian-Early Turonian,Yaojia Formation to Later Turonian-Coniacian,Nenjiang Formation to Santonian-Campanian.Sifangtai and Minshui Formations to Maastrichtian. 4.Analysis of lithology,lithofacies and microfossils of Cretaceous in Songliao Basin, shows that shore and shallow lake facies yield the most abundant microfossil groups,and the predelta and deltaic distributary plain facies rich in fossils as well.In the shore and shallow lake areas during the high level periods(such as Qingshankou and Nenjiang sedimentary periods),the lacustrine biota are of high diversity and high abundance.

因此，松辽盆地上、下白垩统的界线应在泉头组的底界，即泉头组与登娄库组之间，而不是泉头组的顶界。2、青山口组一段黑色泥岩、页岩具有有机碳含量高、重排甾烷含量低，生物标志物出现28，30—双降藿烷和伽马蜡烷，干酷根碳同位素具有正向偏移等有机地球化学特征，表征为青山口组一段黑色页岩、油页岩是古湖泊缺氧事件的产物，它对应于白垩纪古海洋Cenomanian—Turonian期界线附近缺氧事件，二者具同步性。3、通过生物地层学、年代地层学、磁性地层学和事件地层学研究，认为泉头阶大体相当于Cenomanian阶，青山口阶相当于晚Cenomanian—早Turonian阶，姚家阶对应于晚Turonian—Coniacian阶，嫩江阶对应于Santonian—Campanian阶，四方台阶和明水阶相当于Maastrichtian阶。4、通过对松辽盆地上白垩统的岩性、岩相及微体化石分析，认为滨浅湖相是微体生物群最为发育的相带，其次为三角洲前缘相和三角洲分流平原相。

This dissertation was focused on the research about the formation and evolution of NQB from the Late Triassic to the early middle Epoch of Jurassic Period, including integrated analyzing the characteristic of the key stratigraphic surfaces, the time of the key stratigraphy, regional rock straigraphy, biostratigraphy and chronostratigraphy, sedimentary system and depositional facies. On basis of these analysis, a tectonic evolution model have been established for NQB during from the Late Triassic to the early middle Epoch of Jurassic Period.1. After the systematic surface analysis about main stratigraphy units, we found that:(1) the bottom of Xiaochaka formation was comformity with the middle Triassic in the basin, and in the north margin it was deposited and overlapped on the different period stratigraphy before Triassic.(2) The top surface of Xiaochaka formation developed regionally karst and paleo-karst breccia, and was uncomformity with Nadigangri Formation, these things suggest that NQB in Xiaochaka depositing stage was developed from middle Triassic basin, and then an extensive regression occurred, the deposition was over and erosion come into being.(3) The lithologic assemblage, geochemistry, mixed fossils, and stratigraphy overlapping characteristic of Quemocuo Formation in early middle Jurassic indicted that the uncomformity surface was an extension-unconformity.2. Integrated analysis about stratigraphy division and correlation indicted that:(1) the paleontologic assemblage of Xiaochaka formation show its time was Carian -Norian stage of late Triassic. According to it was overlapped by late Triassic Nadigangri Formation, so Xiaochaka formation should be Carian - early Norian stage.(2) the SHRIMP Zircon U-Pb age of Nadigangri formation volcanic rocks wear vary form 216 to 205 Ma, so its time should be Norian, but maybe extended into Rhaetian Stage.(3) The age of its bottom volcanic rocks, the fossil assemblages of its middle and upper members and overlapped by lower Jurassic, indicted the age of Riganpeicuo Formation was Norian - Rhaetian stage. And the same time, the volcanic rocks geochemistry of Nadigangri and Riganpeicuo formation both reflected that they wear formed in rift tectonic settings. The lower lithologic and surface characteristic, fossil assemblages and its upper maybe was conformity with lower Jurassic, all reflected that the age of Tumengela Formation in Tumen area should be Norian - Rhaetian stage.

论文对晚三叠世—中侏罗世早期盆地的形成与演化开展了研究，包括关键地层界面特征分析、关键地层时代归属分析、区域岩石地层、生物地层和年代地层的综合对比分析、区域沉积体系与沉积相分析、岩相古地理分析，最终建立晚三叠世—中侏罗世早期羌塘盆沉积—构造动力演化模式。1、系统的对各地层单元的界面分析发现：(1)肖茶卡组底界在盆地内部与中三叠统整合关系，在盆地北缘为沉积超覆于不同时代的前三叠系之上：(2)肖茶卡组顶界面发育古岩溶角砾岩，与上覆那底岗日组为岩溶不整合接触，说明肖茶卡组沉积时期的羌塘盆地是在早中三叠世的盆地基础发展起来的，后期出现了广泛的海退事件，使盆地结束沉积并遭受风化剥蚀作用；(3)中侏罗统雀莫错组的岩性组合特征、岩石化学特征、古生物化石混积和地层的沉积超覆现象均表现出裂陷环境下形成的伸展不整合面的特征。2、综合地层划分与对比分析认为：(1)肖茶卡组古生物化石组合反映其时代为晚三叠世卡尼期—若利期，根据其上被上三叠统那底岗日组不整合覆盖，将其时代厘定为卡尼期—若利期早期；(2)那底岗日组火山岩SHRIMP锆石U-Pb年龄在216～205 Ma之间，其时代主要为若利期，可能包含有瑞替期：(3)日干配错组底部火山岩的年龄、中上部化石组合及其被下侏罗统整合覆盖，综合反映的时代为晚三叠世若利期—瑞替期，而且那底岗日组火山岩和日干配错组火山岩的地球化学成分分析反映两者均为引张构造背景下的产物；土门地区的土门各拉组的下部岩性及界面特征、化石组合和上部可能被下侏罗统整合覆盖，综合反映其时代为若利期—若利期。

The principal contents of the symposia on stratigraphy in the 31st International Geological Congress comprise the following aspects:geologic time scale, biostratigraphy, event stratigraphy, sequence stratigraphy, magnetostratigraphy, isotopic stratigraphy, integrated stratigraphy, sedimentary facies and palaeogeography, palaeobiogeography, and tectono-palaeogeography.

介绍了第 3 1届国际地质大会有关地层学学术讨论的主要内容，包括地质年代表、生物地层学、事件地层学、层序地层学、磁性地层学、同位素地层学、综合地层学、沉积相与沉积古地理、生物古地理、构造古地理 10个方面。

The journal well informs the research advances in this field, ranging from marine palynomorphs to higher land plants, including systematics, evolution, palaeobiology, palaeoecology, biostratigraphy, biochronology, palaeoclimatology, paleogeography, palaeoenvironmental reconstructions, palaeobotany and palynology etc.

该杂志全面提供了从海洋孢粉型到高原植物研究领域的进展，包括分类学、进化、古生物学、古生态学、生物地层学、生物年代学、古气候学、古地理学、古环境重建、古植物学以及孢粉学等等。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失