关于鲁西侏罗纪一白垩纪岩石地层单位使用之我见

在中生代山东分为鲁东、鲁西、华北平原三个地层分区。鲁西地层分区在不同时期、不同研究者建立和使用了许多不同的岩石地层单位，使用比较混乱。本文对相关的岩石地层单位进行了讨论，提出了新的划分方案。侏罗系建议使用淄博群，划分为中、下侏罗统的坊子组和中、上侏罗统的三台组；白垩系建议使用下白垩统蒙阴组和西洼组；上白垩统固城组。其中固城组的时代根据所产化石由原来归为古新统而改为上白垩统。同时建议，废除“汶南（亚）组”和“分水岭（亚）组”，并且在鲁西地层分区不使用鲁东地层分区的“杨家庄组”、“曲格庄组”、“八亩地组”等岩石地层单位。     

山东省中生代地层划分与对比

对山东省中生代地层的研究表明：沂沐断裂带以西的鲁西南、鲁中、鲁北地区侏罗纪、白垩纪地层发育较全，而断裂带以东的钱是东地区仅发育白垩纪地层；断裂带两侧中生代地层的化石组合、火山岩特点等都相差很大。本文将沂沭断裂带以西的坊子组归于下－中侏罗纪，三台组归于中侏罗统，分水岭组暂归于上侏罗统、西洼组归于下白垩统；而将沂沐断裂带以东的莱阳组、青山组归于下白垩统。王氏组归于上白垩统。笔者废除使用蒙阴群(组)和汶南(亚)组，并建设将鲁北地区目前使用的“王氏组” 废除，另建新名。     

松辽盆地深层火山岩储层岩相特征和天然气的来源

松辽盆地发育上下两个盆地充填序列：下部充填序列指埋深〉3000m的上侏罗统-下白垩统断陷期火山成因地层，自下而上划分为火石岭组、沙河子组和营城组；上部充填序列由下白垩统上部-上白垩统坳陷期正常的沉积地层组成。下部充填序列的营城组火山岩是松辽盆地北部深层天然气的主要储集层（占储层的87％）。火山岩储层物性受控于火山岩岩相，喷溢相上部亚相（Ⅲ3）和侵出相。内带亚相（Ⅳ1）是最有利的火山岩储层，火山通道相火山颈亚相（Ⅰ1）、隐爆角砾岩亚相（Ⅰ3）和爆发相热碎屑流亚相（Ⅱ3））也是较好的储层。在松辽盆地北部徐家围子断陷火山岩储层中发现的工业气藏天然气有烃类、CO2、N2、H2S和少量稀有气体。通过天然气组成，烃类和CO2，碳同位素组成分析，认识到徐家围子断陷火山岩气藏天然气主要为煤型气、油型气和无机气构成的混合气，无机成因CO2气可能源于地幔或是岩浆成因。     

皖南郎溪下白垩统地层和苏北连云港海滩岩的发现

皖南郎溪下白垩统地层和苏北连云港海滩岩的发现钟华邦（江苏省地矿局地调所）１皖南郎溪县下白垩统地层的发现在笔者参加１：５万区调工作范围内，在皖南郎溪白茅岭地区有一套独特的地层。前人将其划归上侏罗统，也有人将其归为上三叠统。笔者通过野外调查取样、室内鉴定...     

鄂尔多斯东北缘东胜地区下白垩统划分的有关问题

鄂尔多斯东北缘东胜地区下白垩统的地层划分一直存在分歧。依据地层的沉积成因及保存特征 ,通过地层的相变关系及其对比分析 ,指出了东胜组和伊金霍洛组划分方案的不合理性 ,提出了该区下白垩统划分可采用三普的命名与划分方案     

关于鲁西侏罗纪-白垩纪岩石地层单位使用之我见

在中生代山东分为鲁东、鲁西、华北平原三个地层分区。鲁西地层分区在不同时期、不同研究者建立和使用了许多不同的岩石地层单位,使用比较混乱。本文对相关的岩石地层单位进行了讨论,提出了新的划分方案。侏罗系建议使用淄博群,划分为中、下侏罗统的坊子组和中、上侏罗统的三台组;白垩系建议使用下白垩统蒙阴组和西洼组;上白垩统固城组。其中固城组的时代根据所产化石由原来归为古新统而改为上白垩统。同时建议,废除“汶南(亚)组”和“分水岭(亚)组”,并且在鲁西地层分区不使用鲁东地层分区的“杨家庄组”、“曲格庄组”、“八亩地组”等岩石地层单位。     

兰州-民和盆地红古城组的建立及其地质学意义

兰州—民和盆地下白垩统地层,出露良好,厚度较大,自下而上可建立８个非正式的岩石地层单位（岩组）。红古城组位于下白垩统上部的第七岩组。该组以剖面连续、出露甚好、顶底清楚、厚度不大而与上、下地层显著不同,具独特的岩性、岩相特征。虽然岩性、岩相在横向上变化较快,但顶、底界线都具良好的标志层,在盆地内可以广泛追索和对比。该组岩石地层单位的正式建立,不仅便于区内地层的划分与对比,而且对盆内层序地层、岩相分析、构造演化的研究都具重要意义。     

中原油气区侏罗系地层特征

综述中原油气区侏罗系地层古生物特征,提出该区存在下侏罗统—中侏罗统,未确证存在上侏罗统,过去所称上侏罗统—下白垩统归入下白垩统为宜。提出了区内北部临清坳陷的下侏罗统—中侏罗统地层可划分为中一下侏罗统的坊子组和中侏罗统的三台组、西南部济源凹陷下侏罗统的鞍腰组和中侏罗统马凹组、东南部黄口凹陷仅存在中侏罗统的三台组、南部中牟凹陷的侏罗纪地层与济源凹陷的相近,并提出了它们之间的对比意见。     

西藏边坝-洛隆地区下白垩统边坝组的建立及其意义

边坝组是新建立的一个岩石地层单位。该组与下伏下白垩统多尼组呈整合接触,与上覆上白垩统宗给组呈角度不整合接触关系。岩性以紫红色深灰色粉砂质泥岩夹薄层白云岩为特征,深灰色薄层粉砂质泥岩中产丰富的双壳类化石Trigonioides(Diversitrigonioides)xizangensis-Pleuromya spitiensis组合。边坝组的建立完善了该地区下白垩统地层系统,对冈底斯北缘弧后前陆盆地白垩纪岩相古地理研究具有重要意义。     

安徽贵池地区晚白垩世恐龙蛋化石的发现

贵池市郊区桂畈、古潭湖一带上白垩统宣南组中恐龙蛋化石——粗皮蛋（ＯｏｌｉｔｈｅｓｒｕｇｕｓｔｕｓＹａｎｇ）的首次发现,给贵池地区晚白垩世地层的对比与划分提供了化石依据。     

福建白垩纪红层火山岩夹层时代及构造意义

为了研究福建省白垩纪红层形成的时代及构造背景,在政和-大埔断裂以西选取典型红层盆地,对不同盆地内火山岩夹层进行LA-ICP-MS锆石同位素定年和岩石地球化学分析.同位素U-Pb测年结果显示:沙县组的时限较长,为127~87 Ma,其总体时代应大致相当于晚白垩世早期,下部层段跨入早白垩世晚期;崇安组年龄为100.0±1.2 Ma,形成时代为晚白垩世早期.岩石地球化学结果表明,白垩纪红层中的火山岩为壳源成因,是处伸展环境下,为构造活动引起区域断陷拉张作用形成的一套钙碱性系列流纹岩.      

First occurrence of tyrannosaurid theropods from the Corral de Enmedio Formation (Upper Cretaceous) Sonora,México

The Cabullona Basin in the state of Sonora, Mexico is becoming recognized due to its diversity of southern Laramidian continental vertebrates, especially dinosaurs. In this study we describe and analyze three theropod teeth (ERNO specimens) that were found isolated and surface collected in the Corral de Enmedio Formation (Cabullona Group, Upper Cretaceous). The three specimens possess similar morphological characteristics that match the ones present in Late Cretaceous Laramidian tyrannosaurids, so they were referred to the Tyrannosauridae, probably belonging to a new unknown taxon. The implementation of statistical and cladistic analyses corroborated their taxonomical assignment. ERNO specimens correspond to the first record of tyrannosaurid dinosaurs in the basal Corral de Enmedio Formation, extending the stratigraphic distribution of these dinosaurs in the Cabullona Basin. Although tyrannosaurids have been previously described in the Cabullona Basin, the ERNO specimens of the Corral de Enmedio Formation seem to be different, because they possess more labiolingually compressed teeth. This new evidence could indicate a higher taxonomic diversity of the tyrannosaurid theropods that were present in the Cabullona Basin, adding more information to the Tyrannosauridae diversification on one of the most southern Laramidian regions during the Late Cretaceous.     

库车坳陷晚白垩世地层存在的证据和沉积相分析

库车坳陷是我国重要的能源基地之一,白垩系是其主要储层。长期以来,该坳陷白垩系的地层划分存在较大争议,其中是否存在上白垩统是争议问题焦点之一。笔者等根据发现的晚白垩世钙质超微化石,证实了库车坳陷巴什基奇克组上部地层属于晚白垩世并存在海相沉积;根据前人在库车坳陷及塔东北井下发现的晚白垩世介形虫、轮藻等化石,证实了这些地区也同样存在上白垩统,古城组是其晚白垩世陆相沉积的代表。若干露头剖面和井下岩芯晚白垩世钙质超微化石的发现,表明特提斯海水曾侵进到该盆地。该坳陷及塔东北地区晚白垩世存在海相和陆相两类沉积体系。     

浙江白垩系上部地层的划分与对比

浙江白垩系上部地层可划分为永康群、天台群和衢江群 ,长期以来 ,认为天台群和衢江群不整合覆于永康群之上。通过对代表性盆地岩石地层层序、古生物、同位素年龄资料的综合分析 ,发现三个群的下部地层 (馆头组、中戴组和天台盆地的塘上组 )为下白垩统 ,上部为上白垩统 ;天台盆地塘上组与仙居盆地小平田组为同物异名的早白垩世晚期火山岩层 ,覆于小平田组之上的“塘上组”是两头塘组的下部层位 ;永康生物群和衢江生物群的主要生物化石时代分别为早白垩世晚期和晚白垩世早期 ,但就两个生物群所涵盖的永康群和衢江群生物化石总体而言 ,其时代均应为早白垩世晚期至晚白垩世早期。永康群、天台群和衢江群是早白垩世晚期至晚白垩世时期的同期异相堆积 ,不存在相互叠覆关系。     

Burial Records of Reactive Iron in Cretaceous Black Shales and Oceanic Red Beds from Southern Tibet

One of the new directions in the field of Cretaceous research is to elucidate the mechanism of the sedimentary transition from the Cretaceous black shales to oceanic red beds. A chemical sequential extraction method was applied to these two types of rocks from southern Tibet to investigate the burial records of reactive iron. Results indicate that carbonate-associated iron and pyrite are relatively enriched in the black shales, but depleted or absent in red beds. The main feature of the reactive iron in the red beds is relative enrichment of iron oxides （largely hematite）, which occurred during syn-depostion or early diagenesis. The ratio between iron oxides and the total iron indicates an oxygen-enriched environment for red bed deposition. A comparison between the reactive iron burial records and proxies of paleo-productivity suggests that paleo-productivity decreases when the ratio between iron oxides and the total iron increases in the red beds. This phenomenon could imply that the relationship between marine redox and productivity might be one of the reasons for the sedimentary transition from Cretaceous black shale to oceanic red bed deposition.     

Spherules from the Late Cretaceous Phosphorite of the Fatehgarh Formation, Barmer Basin, India

A first report of discovery of spherules, glassy balls, highly magnetic fine dust and microbracciated matrix in the Fatehgarh Formation of Barmer Basin, Rajasthan, India is being presented in this paper. The Fatehgarh Formation is a mixed siliciclastic, carbonate and phosphorite formation of Cretaceous age in the Barmer Basin that comprises sediments of Middle Jurassic to Lower Eocene age. The phosphorite zone in the Fatehgarh Formation is 8 metre-thick zone that comprises phosphatic sandstone, bone bed, bedded phosphorite and phosphatic and non phosphatic gastropod beds. The spherules occur in a thin phosphatic-clay mud and silt band of bone bed, which also yielded a very rich and diverse microvertebrate assemblage with a dominant Late Cretaceous (Maastrichtian) form of Igdabatis along with forms comprising of Semionodontid, Lapisosteum and Enchodontid. The end Cretaceous is marked for a mass extinction of numerous species including dinosaurs. An extraterrestrial impact is interpreted as the reason for this mass extinction. Whether these spherules are related to the volcanic source or K/T Boundary impact ejecta found at Caribbean and Gulf of Mexico region needs detailed chemical and age characterization for which study is in progress.     

塔里木北部库车前陆盆地晚白垩世和古新世的钙质超微化石组合

库车前陆盆地是中国大型油气基地之一,盆地中的白垩系及古近系为盆地油气的主要储层。对本区白垩系的时代划分和沉积环境的精确确定直接关系到对油气田的规模、储量和分布范围的正确评价。本研究在前人划分为陆相下白垩统巴什基奇克组的顶部首次发现了由10属15种组成的晚白垩世海相钙质超微化石组合Arkangelskiellacymbiformis—Quadrumgartneri。此外,在由前人定为古新统—始新统的塔拉克组下段也发现了晚白垩世Arkangel skiellacymbiformis—Quadrumgartneri组合,在该组上段发现了古新世化石Biantholithussparsus。该成果既为准确确定这两个岩组的地质时代提供了可靠的古生物证据,又为本区存在晚白垩世地层和海相沉积提供了佐证,表明巴什基奇克组顶部存在晚白垩世的海相沉积,塔拉克组下段属于上白垩统,上段属于古新统。     

Discovery of Radiolaria from the Zongzhuo Formation in Tianba,Kangmar,Tibet and its Age Implication

Abstract: There is a group of variegated marine deposits, including the red beds widespread in the area of Tianba, Kangmar, southern Tibet, which previous works have contributed to Cretaceous Zongzhuo Formation by lithologic associations only, but with poor fossil evidence. Due to the absence of age dating fossils, the red bed age is obscure. Abundant Cretaceous radiolaria were discovered from the Zongzhuo Formation in the present study. In spite of the poor general preservation of some radiolarian specimens as recrystallized quartz infillings, 58 species from 46 genera of radiolaria, extracted from chert and silicous limestone of the Zongzhuo Formation in Kangmar, were identified on the basis of their shape and ornamentation. Based on the radiolaria, the age of the Zongzhuo Formation of this area has been referred to as Late Cretaceous. The new radiolarian data from the Zongzhuo Formation of Tianba area provide a local basis to correlate these deposits with other regions of the Tethyan Himalaya.     

西藏隆格尔铁矿床成岩成矿时代及对区域多期铁成矿作用的启示:地球化学、锆石U⁃Pb及金云母Ar⁃Ar同位素定年约束

为了查明冈底斯成矿带隆格尔富铁矿床的成矿时代、形成环境及其对区域铁成矿作用的指示,对该矿床开展了岩石地球化学、锆石U-Pb年代学和Lu-Hf同位素及金云母Ar-Ar定年分析,结果表明:(1)矿区存在早白垩世花岗闪长岩(116.3 Ma)和晚白垩世闪长岩(94.3~93.8 Ma)两个阶段的岩浆活动,主矿体金云母40Ar/39Ar等时线年龄为93.71±2.96 Ma,表明该铁矿形成于晚白垩世;(2)与主矿体成矿相关的闪长岩具较低SiO₂含量(52.17%~55.32%),富集LREE及Rb、Ba、Pb等大离子亲石元素,亏损HREE和Nb、Ta、Ti等高场强元素,属于高钾钙碱性和准铝质岩石系列,锆石ε_Hf(t)介于1.4~3.6,Mg#指数极高(0.59~0.64),暗示成矿岩体有较多的幔源物质加入,具有壳幔混合特征;(3)结合冈底斯带其他铁矿床时代,可以将冈底斯铁成矿作用划分为~115 Ma、~94 Ma和50~65 Ma三期,隆格尔铁矿床属于冈底斯带新一期(晚白垩世)富铁成矿作用;(4)对比冈底斯成矿带多阶段矽卡岩型铁成矿作用发现,隆格尔铁矿成矿岩体与其他时期铁矿具有明显的地球化学差异,幔源物质较多的中基性岩浆相对于酸性岩浆可能更容易形成富铁矿床.      

福建泰宁白垩纪红层植物及孢粉化石组合特征

泰宁白垩纪红层盆地由朱口、梅口、龙安3个盆地组成,盆地内出露的岩石地层为沙县组和崇安组。近期工作,首次在龙安盆地沙县组采获植物化石和孢粉化石,梅口盆地崇安组采获孢粉化石。根据植物化石及孢粉组合特征,沙县组地质时代为晚白垩世早、中期,相当于赛诺曼期-土仑期(Cenomanian-Turonian);崇安组为晚白垩世晚期,相当于康尼亚克期-马斯特里赫特期(Coniacian-Maastrichtian)。依据泰宁梅口盆地崇安组孢粉组合特征,建立晚白垩世晚期Pinuspollenites-Ulmipollenites minor组合,以代表福建白垩纪第Ⅵ孢粉组合。