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1.
西藏南部江孜地区白垩系的厘定 总被引：32，自引：3，他引：29
文中对藏南江孜地区深海一次深海白垩纪地层层序、系统及厚度进行了厘定。建组剖面甲不热、维美等构造复杂,地层层序变化大,重复多。厘定后的岩石层单元有加不拉组、床得组和宗卓组。加不拉组是一套以黑色页岩为主的地层,跨不白垩统一上白垩统三冬阶,下分黑层段和白层段;床得组由紫红色页片状泥灰岩组成,各坎潘期早－中期;宗且即著名的“北家混杂堆积岩”,页岩中含大量外来岩块,时代为坎潘期晚期和马斯特里赫特期。白垩系厚 相似文献
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对“西藏南部江孜地区白垩系的厘定”一文的商榷 总被引：1，自引：1，他引：0
藏南江孜地区的白垩系,50年代以来,一直分为下部的加不拉组和上部的宗卓组,时代大体相当于早、晚白垩世。吴浩若(1987)又在宗卓组上部分出床得组。王成善等(2000)认为地层层序是宗卓组在床得组之上,并将加不拉组时代上延到晚白垩世的Santonian。白垩系在藏南分布广泛,本区又是西藏白垩系的标准地点之一。这些变动,对西藏地质研究和 相似文献
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西藏中部若干地层问题讨论 总被引：2，自引：0，他引：2
野外考察和有关的研究结果表明，白垩纪阿尔布—赛诺曼期，在西藏中部沉积了由海相灰岩组成的郎山组；白垩纪坎潘期，在班戈一带出现由磨拉石建造组成的竞柱山组；新近纪中—上新世，西藏中部沉积了湖相的丁青组。因此，前人关于该区一些地层归属的厘定值得商榷。 相似文献
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新疆喇嘛苏铜矿成矿地质条件 总被引：7，自引：0，他引：7
喇嘛苏铜矿床矿化类型为接触带、断裂裂隙、岩浆期后热液型，其成矿受断裂、岩体和层位联合控制．今后找矿（１）黄铁矿化砂砾屑结晶灰岩、矽卡岩化灰岩与ＮＥ、ＮＷ向成矿期断裂的交汇、复合处；（２）岩体与ＪｘＫｓ－Ｊｘｋｓ的不整合接触处，岩体的“内湾、外湾”构造和岩体超覆接触处；（３）ＮＥ向成矿期断裂与其它构造带的迭加地段． 相似文献
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《地学前缘》2017,(1):174-194
岩石地层的厘定是一件基础而重要的工作,集中体现了一个阶段对地层的综合认识水平;对一个地区而言,建立行之有效的岩石地层划分方案具有重要的意义。文中详细介绍和评述了藏南白垩纪—古近纪(含中新世)33个岩石地层单元,其中特提斯喜马拉雅南带13个、特提斯喜马拉雅北带9个、日喀则弧前盆地带9个、雅鲁藏布缝合带2个。特提斯喜马拉雅南带白垩系包括古错村组、东山组、察且拉组、冷青热组、波林夏拉组、岗巴村口组、旧堡组、遮普惹山坡组、宗山组;古近系包括基堵拉组、宗浦组、恩巴组、扎果组;特提斯喜马拉雅北带白垩系包括维美组、日朗组、甲不拉组、床得组;古近系包括宗卓组、甲查拉组、蹬岗组、桑单林组、者雅组;日喀则弧前盆地带白垩系包括桑祖岗组、昂仁组、帕达那组、曲贝亚组,古近系包括曲下组、加拉孜组、达金组;中新统包括秋乌组、大竹卡组;雅鲁藏布缝合带包括白垩系冲堆组、渐新统—中新统柳区群。文中在结合物源分析、盆地演化等研究资料基础上,划分了7个构造地层单元:其中印度-亚洲大陆碰撞后的新生代2个(TS1、TS2)、碰撞前白垩纪印度北缘3个(TSI3、TSI4、TSI5)、亚洲南缘2个(TSL3、TSL4)。 相似文献
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西藏沙丁、荣布地区三叠系—老第三系沉积地质特征 总被引：1，自引：1，他引：0
研究区从三叠纪到老第三纪,发育的岩石地层主要有确哈拉群（Ｔ３）、希湖群（Ｊ１－２）、拉贡塘组（Ｊ２－３）、多尼组（Ｋ１）、竟柱山组（Ｋ２）和牛堡组（Ｅ２－３）。在沉积相上,经历了从深水沉积到浅水直至陆相沉积的演变,发育有冲积扇、河流、湖泊、三角洲（潮汐）、障壁海岸、浅海、深海和火山碎屑流沉积。古地理分析表明,研究区晚三叠世古地理轮廓是一个从东南向西北和东北方向由浅水碳酸盐台地及深水陆层海底扇沉积共同发育的沉积盆地;早中侏罗世,演变成为一个由深水砂质浊积岩和细屑浊积岩组成的水下席状体沉积;进入中晚侏罗世,其古地理表现为一个陆屑浅海有障壁海岸;到了晚白垩世,研究区表现为以含煤沉积为特征的三角洲相沉积。 相似文献
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赣南中生代火火活动时代及岩浆来源 总被引：9，自引：0，他引：9
同位素地质研究表明，赣南中生代火山活动分属侏罗纪和白垩纪两大旋回，火山地层的时序为菖蒲组（Ｊ２），鸡笼嶂组（Ｊ３）、路径金伯利金砾岩（Ｋ１），赣州组（Ｋ１＾２－Ｋ２＾１），版石组（Ｋ２＾２）；火山岩浆属壳幔混源型，不同活动时期壳幔组分比例呈规律性变化，是板内深断裂作用的产物。 相似文献
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在熔融的２ＰｂＯ．Ｂ２Ｏ３中（９７４Ｋ）,用滴溶量热法测定了２９８Ｋ下由组分Ｋ２ＣＯ３和ＣａＣＯ３形成的复碳酸盐Ｋ２Ｃａ（ＣＯ３）２（它有胶方解石和碳钾钙石两种多型）和Ｋ２Ｃａ２（ＣＯ３）３为－７．２±５．８ｋＪ／ｍｏｌ。同时推算出了复碳酸盐生砀熵变ΔＳｔ。假定具有序结构的胶方解石的ΔＳｔ＝０,则碳钾钙石的生成熵为４０．９±５．１Ｊ／ｍｏｌ．Ｋ,Ｋ２Ｃａ２（ＣＯ３）３为３９．４±７．３Ｊ／ｍｏｌ． 相似文献
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The planktic foraminifera of the Chuangde Formation (Upper Cretaceous Oceanic Red Beds, CORBs) as exposed at Tianbadong section, Kangmar, southern Tibet has been firstly studied for a detailed for a detailed biostratigraphy elaboration. A rich and well-preserved planktic foraminifera were recovered from the Chuangde Formation of the Tianbadong section and the Globotruncanita elevata, Globotruncana ventricosa, Radotruncana calcarata, Globotruncanella havanensis, Globotruncana aegyptiaca, Gansserina gansseri and Abathomphalus mayaroensis zones have been recognized. The planktic foraminiferal assemblage points to an early Campanian to Maastrichitian age for the CORBs of the eastern North Tethyan Himalayan sub-belt, which also provides a better understanding of the shifting progress of the Indian Plate to the north and the evolution of the Neotethyan ocean. The lithostratigraphy of the Chuangde Formation of the Tianbadong section comprises two lithological sequences observed in ascending succession: a lower unit (the Shale Member) mainly composed of purple (cherry-red, violet-red) shales with interbedded siltstones and siliceous rocks; and an upper unit (the Limestone Member) of variegated limestones. The strata of the Chuangde Formation in the Tianbadong section are similar to CORBs in other parts of the northern Tethyan Himalaya area of Asia (Gyangze, Sa’gya, Sangdanlin, northern Zanskar, etc.). The fossil contents of the Chuangde Formation in the sections (CORBs) studied provide a means of correlation with the zonation schemes for those of the northern Tethyan Himalayan sub-belt and the Upper Cretaceous of the southern Tethyan Himalayan sub-belt. Paleogeographic reconstruction for the Late Cretaceous indicates that the Upper Cretaceous Chuangde Formation (CORBs) and correlatable strata in northern Zanskar were representative of slope to basinal deposits, which were situated in the northern Tethyan Belt. Correlatable Cretaceous strata in Spiti and Gamba situated in the southern Tethyan Belt in contrast were deposited in shelf environments along the Tethyan Himalayan passive margin. CORBs are most likely formed by the oxidation of Fe(II)-enriched, anoxic deep ocean water near the chemocline that separated the oxic oceanic surface from the anoxic. 相似文献
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MARINE SOURCE ROCKS AND THEIR DEPOSITIONAL CONDITIONS OF MESOZOIC—CENOZOIC IN THE GAMBA—TINGRE BASIN,SOUTH TIBET:ORGANIC GEOCHEMICAL STUDY1 FuJiamo ,ShengGuoying ,XuJiayou,et.al.ApplicationofbiologicalmarkersintheassessmentofpaleoenvironmentsofChinesenon marinesediments[J] .OrganicGeochemistry ,1990 ,16 :76 9～ 779.
2 JenkynsHC .Cretaceousanoxicevents:fromcontinentstooceans[J] .JournaloftheGeologicalSociety ,1980 ,137:171～188.
… 相似文献
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西藏吉隆地区白垩纪复理石相遗迹化石及其地质意义 总被引：1，自引：0，他引：1
系统描述了西藏南部吉隆地区白垩纪甲不拉组和宗卓组首次发现的复理石相遗迹化石5属、7种。主要遗迹属有Chondrites,Cosmorhophe helminthoida,Muensteria,Phycosiphon,Phymatoderma。遗迹化石的形态、习性、水深分布等环境成因特征清楚地显示其为深海Nereites遗迹相的典型代表，反映复理石相深水沉积环境特征。 相似文献
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The Wapiti Formation in west-central Alberta preserves one of the most diverse Late Cretaceous terrestrial track records yet identified in Canada. At least seven morphotypes are recognized and attributed to mammals, small reptiles or amphibians, tyrannosaurids, medium-sized theropods, hadrosaurids, and ankylosaurs. Most tracks occur isolated on slump blocks associated with latest Campanian (Wapiti Formation unit 4) exposures found along Pipestone Creek and Red Willow River. With the possible exception of hadrosaurids, tracks provide some of the most compelling evidence for the occurrence of such taxa within the Wapiti Formation ecosystem. The apparent absence of ceratopsian tracks is surprising considering their bones are abundantly preserved in nearby monodominant bonebeds. The overall faunal signal represented by the Wapiti Formation trackmakers is typical of and consistent with other coeval assemblages in similar environments. The Wapiti Formation tracks, combined with the known fossil bone record, provide another data point in a growing palaeobiogeographical picture of the dinosaur faunas of high-latitude northwestern North America during the Late Cretaceous. 相似文献
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Tyrannosaurs and hadrosaurs from the Late Cretaceous of eastern North America (Appalachia) are distinct from those found in western North America (Laramidia), suggesting that eastern North America was isolated during the Late Cretaceous. However, the Late Cretaceous fauna of Appalachia remains poorly known. Here, a partial maxilla from the Campanian Tar Heel Formation (Black Creek Group) of North Carolina is shown to represent the first ceratopsian from the Late Cretaceous of eastern North America. The specimen has short alveolar slots, a ventrally projected toothrow, a long dentigerous process overlapped by the ectopterygoid, and a toothrow that curves laterally, a combination of characters unique to the Leptoceratopsidae. The maxilla has a uniquely long, slender and downcurved posterior dentigerous process, suggesting a specialized feeding strategy. The presence of a highly specialized ceratopsian in eastern North America supports the hypothesis that Appalachia underwent an extended period of isolation during the Late Cretaceous, leading the evolution of a distinct dinosaur fauna dominated by basal tyrannosauroids, basal hadrosaurs, ornithimimosaurs, nodosaurs, and leptoceratopsids. Appalachian vertebrate communities are most similar to those of Laramidia. However some taxa-including leptoceratopsids-are also shared with western Europe, raising the possibility of a Late Cretaceous dispersal route connecting Appalachia and Europe. 相似文献
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Calcareous nannoplankton biostratigraphy has been performed on five sedimentary sections through the marine Akveren Formation from the Bartin region of northern Turkey, on the southern Black Sea coast. This new biostratigraphy provides an age for the formation of the Early Campanian (nannofossil zone UC15aTP) to Early Selandian (nannofossil zone NP5), and highlights the presence of the Campanian/Maastrichtian, Cretaceous/Tertiary (K/T), and Danian/Selandian boundaries in this intermediate palaeolatitude location. Micula murus was identified below the K/T boundary, but Micula prinsii and Nephrolithus frequens were not, which implies that the K/T boundary interval is not complete in the study area. These dates are in agreement with previous micropaleontological studies. 相似文献
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LI Guobiao WAN Xiaoqiao JIANG Ganqing HU Xiumian GOUDEM Nicolas HAN Hongdou CHEN Xi 《《地质学报》英文版》2007,81(6):917-924
As one of the mélanges in the southern side of the Yarlung-Zangbo suture zone, the Saiqu mélange in southern Tibet is important for understanding the evolution of the Neo-Tethys ocean. The age of the Saiqu mélange, however, has been debated due to the lack of reliable fossil evidence in matrix strata. Based on lithological similarities with platform strata in southern Tibet and limited fossils from exotic blocks, previous studies variously ascribed the Saiqu mélange to be Triassic in general, Late Triassic, or Late Cretaceous. Here we reported planktonic foraminiferal faunas from the matrix strata of the Saiqu mélange. The new fossils yield a Late Cretaceous age, which is so far the best age constraint for the mélange. Regional stratigraphic correlation indicates that the Cretaceous Oceanic Red Beds (CORBs) in Saiqu may be time equivalent to the CORBs of the Zongzhuo Formation in neighboring regions. Thus the Saiqu mélange should be correlated to the Upper Cretaceous Zongzhuo Formation rather than the Triassic Xiukang Group, as previously suggested. 相似文献
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西藏江孜-浪卡子一带的侏罗-白垩纪界线地层 总被引：2，自引：0，他引：2
侏罗系/白垩系界线是显生宙所有系级界线中存在问题最多的一个。西藏南部出露有良好的侏罗-白垩纪地层,本次工作在喜马拉雅地层区的康马隆子地层分区开展了海相侏罗系/白垩系的界线研究。江孜地区的界线地层被划分为维美组和甲不拉组;浪卡子地区的甲不拉组之下发育一套含大量火山岩层的火山－沉积地层,被称为桑秀组。该地层分区的地层系统由下至上为：维美组浅灰色厚层状粗-细粒石英砂岩;桑秀组黑色页岩、安山岩和玄武岩;以及甲不拉组黑色页岩、硅质泥页岩夹砂岩和砂质灰岩。维美组中含化石稀少,仅在江孜地区发现零星菊石Haplophylloceras、Himalayites等。桑秀组下部页岩和粉砂岩中找到少量菊石化石,属于Spiticeras、Berriasella、Haplophylloceras的一些种,和富集成层的双壳类Inoceramus everesti等。江孜甲不拉组下部化石丰富,划分为Spiticeras-Berriasella下组合和Himalayaites-Haplophylloceras上组合。本研究区的生物地层可与聂拉木地区的菊石化石组合对比。通过生物地层学对比,江孜-浪卡子地区的维美组时代为晚侏罗世Tithonian期,江孜地区甲不拉组下部和浪卡子地区的桑秀组均属于下白垩统。桑秀组下部的页岩段与江孜甲不拉组的最下部地层相当,上部火山岩的同位素年龄为133 Ma。据此,桑秀组的时代为Berriasian至Hauterivian期,侏罗系/白垩系的界线位于该组之底,以Virgatosphinctes、Aulocosphinctes的消失和Spiticeras的出现为标志。侏罗纪末期西藏特提斯海区普遍形成大规模海退,表现为维美组和门卡墩组顶部砂岩的同期沉积。 相似文献