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1.
华北地块东北缘红庙子盆地鹰嘴砬子组孢粉化石 总被引：1，自引：1，他引：0
报道华北地块东北缘地区红庙子盆地鹰嘴砬子组的孢粉化石,建立了Cicatricosisporites-Abietineaepollenites-Piceites组合,该组合的主要特征为:以裸子类双气囊花粉和海金沙科孢子为主,含一定量裸子类无气囊花粉,未见被子类花粉,孢粉组合特征可与松辽盆地沙河子组对比。一些具有早白垩世时代意义的孢粉化石,如Cicatricosisporites sp.,Cicatricosisporites undulates和Cicatricosisporites implexus的出现,表明鹰嘴砬子组的地质时代为早白垩世。根据孢粉化石资料,推测华北地块东北缘地区在鹰嘴砬子组沉积时期古植被面貌以松科和杉科组成的松柏类针叶林为主,林下生长着真蕨类。古气候相当于湿润-半湿润的亚热带气候。 相似文献
2.
依据东基三井1 226. 0～1 538. 0 m井段的孢粉鉴定结果,结合前人资料,首次将该井段孢粉组合命名为Cyathidites-Taxodiaceaepolleni-Aquilapollenites组合。其组合特征为:裸子植物花粉占48. 10%～78. 58%,蕨类孢子占2. 44%～34. 18%,被子植物花粉占0%～28. 26%;蕨类孢子中Cyathidites百分含量最高(0. 79%～37. 50%),其次是Cicatricosisporites (0%～12. 50%)和Leiotriletes (0%～10. 00%),重要分子有Appendicisporites、Schizaeoisporites、Lygodiumsporites和Lygodioisporites;裸子植物花粉中Inaperturopllenites的百分含量最高(11. 29%～38. 83%),其次是Taxodiaceaepollenites (12. 66%～28. 57%),重要分子有Tsugaepollenites、Parcisporites、Parvisaccites、Ephedripites和Classopollis等;被子植物花粉中Tricolpites的百分含量最高(0%～16. 46%),其次是Betulaepollenites (0%～15. 22%),含量较高的还有Momipites和Tricolporopollenites,重要分子有Aquilapollenites、Fibulapollis和Proteacidites等。该组合可以与松辽盆地嫩江组孢粉组合对比,地质时代为晚白垩世Santonian-Campanian期。鉴于宁安市南团子山、高家等露头区海浪组所产Estherites mitsuishii、E. liuxinensis、Tylestheria cf. shanhoensis、Halysestheria yui、Calestherites sp.和Brachygrapta? sp.等叶肢介化石群,系松辽盆地嫩江组常见分子,故将东基三井1 226. 0～1 538. 0 m井段划归为海浪组,废弃"七星河组"一名。 相似文献
3.
广西桂林地区晚三叠世孢粉组合及其地层意义 总被引：1，自引：0，他引：1
广西桂林地区首次发现晚三叠世孢粉化石２７属３７种,可称为Ｄｉｃｔｙｏｐｈｙｌｉｄｉｔｅｓ－Ｃａｎａｌｉ－ｚｏｎｏｓｐｏｒａ－Ｏｖａｌｉｐｏｌｉｓ－Ｒｉｃｃｉｓｐｏｒｉｔｅｓ组合,其中的主要属种在国内外均为晚三叠世的重要分子,并可与我国华南地区和欧洲有关晚三叠世孢粉组合进行对比。因此,当前组合的地质时代属于晚三叠世,这填补了桂林地区中生代地质发展史中的一个空白。 相似文献
4.
内蒙古海拉尔盆地大磨拐河组孢粉组合 总被引：13，自引：1，他引：13
海拉尔盆地大磨拐河组自下而上可以划分出两个孢粉组合 :哈氏三角孢 -微细云杉粉 ( Deltoidospora hallii-Piceaepollenites exilioides)组合和澳洲无突肋纹孢 -卵形光面单缝孢 ( Cicatricosisporites australiensis- L aevigato-sporites ovatus)组合 ,分别分布于大磨拐河组一段和二段 ,组合特征明显 ,可以作为研究区内地层划分对比的生物地层学依据之一。两个孢粉组合中见有属种繁多的海金沙科孢子及其他繁盛于早白垩世的孢子花粉 ,结合在数以千计的岩心样品中没有发现可靠的早期被子植物花粉的情况分析 ,推测产这两个孢粉组合的大磨拐河组的地质时代为早白垩世凡兰吟期—欧特里沃期 ( Valanginian— Hauterivian) ,不排除部分进入巴列姆期 ( Barrem ian)的可能 相似文献
5.
《China Geology》2022,5(3):439-456
This study identified two palynological assemblages, namely Bayanhuasporites-Cycadopites-Protoconiferus and Cicatricosisporites-Cedripites-Perinopollenites, in the Tongbomiao Formation in the Hongqi Sag in the Hailar Basin, Inner Mongolia, China for the first time. The former is distributed in the lower part of the Tongbomiao Formation and is characterized by abundant gymnosperm pollen and diverse fern spores. Among them, the gymnosperm pollen is dominated by Paleoconifer (4.98%–31.62%) and Cycadopite (8.55%–25.23%) pollen grains and also includes other pollen grains such as Classopollis, Parcisporites, Erlianpollis, Callialasporites, and Jiaohepollis. The fern spores in the former palynological assemblage contain Bayanhuasporite (0–8.96%), Granulatisporites (0.93%–6.97%), and some important Cretaceous genera, such as Cicatricosisporites, Concavissimisporites, Densoisporites, Hsuisporites, Foraminisporis, and Leptolepidites. The Cicatricosisporites-Cedripites-Perinopollenites palynological assemblage is distributed in the upper part of the Tongbomiao Formation. Gymnosperm (77.30%), Pinaceae (31.9%), and Paleoconiferus (19.02%) pollen predominate this palynological assemblage, and Quadraeculina, Erlianpollis, and Jiaohepollis pollen are also common in this assemblage. The fern spores in this palynological assemblage include abundant Cicatricosisporites (4.29%). Besides, Concavissimisporites, Aequitriradites, and Leptolepidites are also common in this palynological assemblage. No angiosperm pollen has been found in both palynological assemblages. The identification of both palynological assemblages provides important evidence for the biostratigraphic correlation between the Hailar Basin and its adjacent areas. It also enables the reconstructions of the Berriasian-Valanginian (Early Cretaceous) vegetation and the paleoclimate on the eastern Mongolian Plateau during 141–132 Ma. The vegetation reconstructed on the palynological data of the represented by Hailar Basin in eastern Mongolian Plateau (141.6–141.4 Ma), form conifer forest or conifer broad-leaved mixed forest to conifer forest with shrubs and grassland, the climate belongs to warm temperate and warm-subtropicalt, the highest temperature is estimated to reach 35–38°C. Form 132.3 Ma, the vegetation type is conifer forest, and its paleoclimate is sub-humid warm temperate, the highest temperature is estimated to reach 24–29°C.©2022 China Geology Editorial Office. 相似文献
6.
内蒙古海拉尔盆地大磨拐河组孢粉化石及其时代浅析 总被引：4，自引：0，他引：4
海拉尔盆地大磨拐河组所产孢粉化石分属于3个孢粉组合.下部孢粉组合以蕨类植物海金沙科孢子为主,重要分子有Cicatricosisporites australiensis, Cyathidites minor, C. gracilis, C. minutaestriatus, Appendicisporites problematicus, A.jonsonii,Pilosisporites verus, Impardecispora apiverrucata, I. purverulenta, Triporoletes reticulates, Aequitriradites echinatus等;中部孢粉组合则以两气囊花粉如Pinuspollenites, Piceaepollenites, Abietineaepollenites, Abiespollenites等占绝大多数,同时见少量被子植物花粉Asteropollis sp., Tricolpites sp.等;上部孢粉组合中裸子植物花粉略有减少,但仍占重要地位,重要分子有Cicatricosisporites australiensis, C. minutaestriatus,C. gushanensis, Impardecispora purverulenta ,Foraminisporites wonthagiensis, Aequitriradites verrucosus, Triporoletes singularis, T. reticulates, Polyporites? sp.等.上述孢粉组合大体可与松辽盆地登娄库组,黑龙江省东部城子河组、穆棱组,辽西地区沙海组、阜新组等对比,代表了中国北方早白垩世特有的植物群面貌,而其中Asteropollis, Tricolpites和Polyporites等被子植物花粉化石的发现,可能暗示大磨拐河组的时代为早白垩世中、晚期的巴列姆(Barremian)期-阿普第(Aptian)期,其上部可能上延至早阿尔必(Albian)期. 相似文献
7.
海拉尔盆地海参1井伊敏组孢粉组合的地层意义 总被引：3，自引：0，他引：3
海参1井伊敏组孢粉化石异常丰富,自下而上可以划分出3个孢粉组合:Impardecispora-Cyathidites-Clavatipollenites组合,Stereisporites-Deltoidospora-Asteropollis组合,Appendicisporites-Asteropollis-Tricolpites组合,分别分布于伊敏组一段、二段和三段,组合特征明显,是海拉尔盆地乌尔逊凹陷划分伊敏组与大磨拐河组的重要生物依据之一,更是伊敏组内三段划分和井间对比的生物依据之一。3个孢粉组合中见有属种繁多的海金沙科孢子及其他繁盛于早白垩世中晚期的孢子花粉,结合在绝大多数样品中发现的早期被子植物花粉的情况分析,推测含这3个孢粉组合的伊敏组地质时代为早白垩世巴列姆期—早阿尔必期(Barremian—Early Albian)。 相似文献
8.
Palynological assemblages of non-marine rocks at the Permian–Triassic boundary, western Guizhou and eastern Yunnan, South China 总被引：1，自引：0，他引：1
Yuanqiao Peng Jianxin Yu Yongqun Gao Fengqing Yang 《Journal of Asian Earth Sciences》2006,28(4-6):291-305
Marine and non-marine facies of the Permian–Triassic boundary stratigraphic set (PTBST) are well developed in South China. Palynological assemblages enable subdivision and correlation of the Permian–Triassic boundary (PTB) rocks. Three palynological assemblages are recognized across the PTBST in two terrestrial PTB sections in western Guizhou and eastern Yunnan, South China. Assemblage 1 (Xuanwei Formation) is a Late Permian palynological assemblage dominated by ferns and pteridosperms, with minor gymnosperms. Most taxa are typical long-ranging Paleozoic forms, but the appearance of Lueckisporites confirms a Late Permian age for this assemblage. Assemblage 2 (PTBST) is marked by an abrupt decrease in palynomorph abundance and diversity, and thriving fungal/algal(?) spores. Assemblage 2 is still dominated by ferns and pteridosperms, with a few gymnosperms, but is characterized by a mixed palynoflora containing both Late Permian and Early Triassic elements. Most taxa are typical Late Permian ones also found in Assemblage 1, however, some taxa of Early Triassic aspect, e.g. Lundbladispora and Taeniaesporites, appeared for the first time. In Assemblage 3 (top Xuanwei Formation and Kayitou Formation), the proportion of gymnosperm pollen increases rapidly, exceeding that of ferns and pteridosperms, but the abundance of palynomorphs is still low. Typical Early Triassic taxa (such as Lundbladispora, Aratrisporites and Taeniaesporites) are present in greater abundance and confirms an Early Triassic age for this assemblage. 相似文献
9.
Tatiana A. Kovaleva Valentina S. Markevich Ge Sun 《Russian Journal of Pacific Geology》2017,11(3):178-190
The taxonomic composition of the palynological assemblage of the Dongning Formation is supplemented. The palynological assemblage corresponds to those from the Lipovtsy Formation (Aptian) in the Razdolnaya Basin of Primorye (Russia) and the Muling Formation (Aptian) in the Jixi Basin of eastern Heilongjiang (China). It is found that the age of the Dongning Formation is Aptian. The palynological assemblage is characterized by dominance of spores of Gleicheniaceae; they are accompanied by spores of Cyatheaceae. The most important feature of the palynological assemblage of the Dongning Formation is the presence of angiosperm pollen (Tricolpites sp., T. micromunus, T. vulgaris, Retitricolpites georgiensis, R. vulgaris, Clavatipollenites hughesii, Quercites sparsus, Fraxiniopollenites variabilis). 相似文献
10.
浙江长兴煤山D剖面早三叠世孢粉组合及全球对比意义 总被引：1，自引：0，他引：1
在长兴煤山D剖面下三叠统殷坑组14 m厚的地层内(第25-60层)密集采孢粉样89件, 从12块样品中获得孢粉化石47属50种, 据此将该剖面下三叠统底部的孢粉组合定为Lundbladispora-Taeniaesporites-Equisetosporites组合.组合中裸子植物花粉占优势, 为59.0%~79.6%;蕨类植物孢子次之, 为20.4%~41.0%;裸子植物花粉中以无肋双气囊类花粉为主, 含量为19.7%~54.4%, 多沟类花粉虽仅见Equisetosporites一属, 但含量高, 最高达24.3%.蕨类植物孢子中光面三缝孢类含量最高, 为14.3%~24.4%, 以圆形的Puncatisporites为主, 最高可达16.2%.孢粉组合Lundbladispora-Taeniaesporites-Equisetosporites与同一剖面的早三叠世牙形石第2带Isarcicella isarcica带及第3带Clarkina carinata-C.planata带相重合.这对当前正在进行的陆相二叠系-三叠系界线的准确划分提供了重要的参照系.研究还表明, 煤山D剖面早三叠世早期的孢粉组合与中国北方区的早三叠世同期的孢粉组合对比较为困难, 而与华南各地的对比较为吻合, 说明中国南、北方古生代孢粉组合向中生代孢粉组合转变的时间并不一致, 北方较早, 南方较晚. 相似文献
11.
新疆库车库尔哈剖面两个新生代孢粉组合的时代和环境意义 总被引：3，自引：0，他引：3
库车盆地的新生界发育比较完整,笔者在库车县城北东方向约50km的库尔哈村西的河谷中测制了剖面。于66层的44号样和90层的50号样品中获得了两个孢粉组合。66层和90层皆属于康村组,两个样品之间相差约200m(真厚度)。在此之前,尚未见到有关康村组孢粉化石的报道。44号样的孢粉组合中被子植物花粉占绝对优势,含量高达94.5%,裸子植物花粉和蕨类植物孢子均少量出现。孢粉面貌反映以草原和灌丛为主的植被类型。50号样的孢粉组合中被子植物花粉占优势(66.5%),裸子植物花粉有较高含量(32.0%),蕨类植物孢子零星出现。孢粉面貌反映盆地周缘广泛分布有以松科为主的高山针叶林带。 相似文献
12.
成吉思汗驿站龙江组剖面位于扎兰屯成吉思汗镇东南部,组内大化石稀少,但孢粉化石丰富,下部岩性为沉凝灰岩、凝灰岩、凝灰质砂岩、砂岩、砾岩,上部岩性为安山岩、英安岩。通过对成吉思汗驿站龙江组孢粉化石的分析,在龙江组中识别出圆形粒面孢-二连粉孢粉组合带(Cyclogranisporites-Erlianpollis)。通过对孢粉化石属种的分析,根据具有时代指示意义的孢粉化石,如Erlianpollis,Cicatricosisporites,Pilosisporites等,认为成吉思汗地区龙江组孢粉化石形成时代为早白垩世,结合地质、古植物及孢粉化石的定量分析,认为龙江组植被类型反映亚热带气候,指示温暖潮湿的环境。 相似文献
13.
In the Rajmahal Basin Lower Cretaceous rocks are classified under the Rajmahal Formation. It includes a series of volcanic basalt flows and associated sedimentary intertrappean beds. Up to 15 basalt flows have been recorded in this basin. The intertrappean beds comprise sandstone, shale, siltstone, and clay deposits which are rich in spores and pollen. The palynoflora recovered from intertrappean beds shows definite pattern of evolution and diversification. On the basis of its overall composition, distribution pattern of age marker taxa and the First Appearance Datum of key taxa, four palynological assemblages have been identified. The chronology of these assemblages in ascending order is (1) Ruffordiaspora australiensis, (2) Foraminisporis wonthaggiensis, (3) Foraminisporis asymmetricus, and (4) Coptospora verrucosa. These assemblages ascertain the age of the volcano-sedimentary sequence of the Rajmahal Formation in the Rajmahal Basin as Berriasian to Aptian. The palynochronology of the intertrappean beds enables their correlation in the Rajmahal Basin. In different areas of the basin, the palynological dating of the lowermost intertrappean bed within the Rajmahal Formation which overlies the Dubrajpur Formation, has provided a Berriasian to Aptian age. The palynological assemblage indicating the Berriasian age is inferred as the time of the initiation of volcanic activity which continued up to the Aptian in the Rajmahal Basin. 相似文献
14.
A palynological investigation of sedimentary rocks enclosing an exceptionally well-preserved fossil dinosaur (Hadrosauridae) discovered in the upper part of the Hell Creek Formation in south western North Dakota was conducted in order to document the immediate paleoenvironment of this dinosaur. The specimen, an Edmontosaurus annectens is remarkable in having exceptional three-dimensional preservation of soft tissue around the skeleton, indicating rapid burial. A well-preserved palynological assemblage dominated by fern and bryophyte spores, with lesser gymnosperm and angiosperm pollen was recovered. Sparse fresh-water algae and marine dinoflagellate cysts were also recorded. The palynofacies is dominated by wood fragments, including charcoal, with little amorphous organic matter. The presence of some typical pollen taxa of the Wodehouseia spinata Assemblage Zone including Striatellipollis striatellus, Tricolpites microreticulatus, Leptopecopites pocockii as well as a diverse suite of Aquilapollenites, is fully consistent with a Late Cretaceous (late Maastrichtian) age. The palynoflora indicates a local vegetation composed of a canopy of conifers dominated by Pinaceae and a minor sub-canopy of Taxodium and cycads, as well as an understory of hydrophilous ferns, mosses and herbaceous angiosperms, indicative of a warm and humid climate – an environment where this specific hadrosaur roamed over 66 million years ago. 相似文献
15.
The angiosperm pollen record from the Anfiteatro de Ticó and Punta del Barco formations (Baqueró Group) is reported. The relevance of these floras is that they are accurately dated as late Aptian, and one of the oldest floras southern South America with fossil angiosperms. Twelve samples were studied, showing Clavatipollenites and Retimonocolpites as dominant types. A new species, Jushingipollis ticoensis sp. nov., is proposed. A doubtful angiosperm pollen grain, Lethomasites sp., is also identified and described. A multivariate analysis of similarities between different Early Cretaceous angiosperm pollen assemblages suggests that the Baqueró Group assemblages have great similarities with other coeval units from Argentina, Australia and United States, which were located in a similar paleolatitude. 相似文献
16.
鄂尔多斯盆地东北部内蒙古伊金霍洛旗乌兰木伦地区是我国重要的能源矿产地,含煤岩系赋存在侏罗系延安组中,延安组岩石组合以灰白色砂岩、灰色粉砂岩、灰色泥岩为主,夹多层煤层;延安组上覆直罗组以灰色、灰绿色砂岩、灰色粉砂岩、紫红色泥岩为主。通过对乌兰木伦地区武家塔露天煤矿剖面延安组和直罗组孢粉化石分析,在延安组中识别出Cyathidites-Lycopodiumsporites-Neoraistrickia-Cycadopites孢粉组合带,以桫椤科、石松科孢子繁盛,紫萁科孢子和单沟/原始沟类、松柏类两气囊花粉发育,卷柏科孢子及柏科花粉较常见为主要特征,时代为中侏罗世早期(阿林期—巴柔期)。根据延安组孢粉母体植物的生态环境分析,本区在这一沉积时期的气候属于温暖湿润的亚热带—温带型气候。直罗组孢粉化石较少,主要见Cyathidites minor,Osmundacidites parvus,Concentrisporites fragilis,Cycadopites spp.等。综合地层岩性、孢粉组合及古植被分析,延安组到直罗组沉积时期总体上呈现从温暖湿润的亚热带—温带型向半干旱—干旱炎热型的气候... 相似文献
17.
海拉尔盆地查干诺尔凹陷扎赉诺尔群孢粉组合 总被引：3，自引：0，他引：3
内蒙古自治区呼伦贝尔盟地区海拉尔盆地查干诺尔凹陷扎赉诺尔群自下而上划分为4个孢粉组合。云杉粉Piceaepollenites sp.-单束松粉Abietineaepollenites sp.-三角粒面孢Granulatisporites sp.组合,分布于大磨拐河组一段;罗汉松粉Podocarpidites sp.-双束松粉Pinuspollenites sp.-无突肋纹孢Cicatricosisporites sp.组合,分布于大磨拐河组二段;无突肋纹孢Cicatricosisporites sp.-刺毛孢Pilosisporite sp.-水龙骨单缝孢Polypodiaceaesporites sp.组合,分布于伊敏组一段;有突肋纹孢Appendicisporites sp.-桫椤孢Cyathidites sp.-星粉Astropollis sp.组合,分布于伊敏组二、三段。上述孢粉组合研究证明,大磨拐河组地质时代为早白垩世凡兰吟期—欧特里夫期(Valanginian-Hauterivian),尽管没有出现最原始的被子植物花粉,但也不排除部分进入巴列姆期(Barremian)的可能,伊敏组的地质时代为早白垩世巴列姆期-阿普第期(Barremian-Aptian)。据此认为扎赉诺尔群地质时代为早白垩世凡兰吟期—阿普第期(Valanginian-Aptian)。 相似文献
18.
Situated at the easternmost area of the Late Mesozoic Jehol Biota, China, abundant fossils, including invertebrates, vertebrates and plants, were collected from the Early Cretaceous Yingzuilazi Formation of the Baishan Basin, southeastern Jilin. The faunal remains from this formation distinctly belong to the Early Cretaceous Lycoptera–Ephemeropsis–Eosestheria assemblage of the Jehol Biota. Based on the gross leaf morphology and epidermal structures, two new species and one indeterminate species of genus Solenites(Czekanowskiales), S. baishanensis sp. nov., S. gracilis sp. nov. and S. sp. are described in this paper. This is the first fossil plant of Czekanowskiales reported from this new fossil locality of the easternmost area of the Late Mesozoic Jehol Biota, China. The new discovery contributes to improve our knowledge for understanding of leaf morphology, epidermal characters and diversity of this genus during the Early Cretaceous time, and extends geologic and geographic distribution of Solenites in northern China and Eurasia. Along with consideration of associated plant and faunal assemblages and sedimentology, we suggest that the regional climate was warm and moderately humid with seasonal temperature and precipitation variations in warm–temperate zone during the Early Cretaceous. 相似文献
19.
Zhang Yun 《Precambrian Research》1985,30(3):277-302
A relatively diverse microbiota, preserved in-situ, has been discovered in cherty stratiform stromatolites of the middle Proterozoic Wumishan Formation (c. 1200–1300 Maold), Jixian Group, in the Ming Tombs area of Beijing. This microfossil assemblage consists of two parts: (1) the mat-building and mat-dwelling benthos which mostly belong to “long-lasting” taxa and are mostly common with those of other Proterozoic microbiotas; and (2) allochthonous elements including some plankton and peculiar structures which are either new forms first described here or taxa shared with some contemporaneous or penecontemporaneous microbiotas elsewhere. The latter may have more stratigraphic significance.Bivariate analysis on two characters measured (length and width) has been used in the classification of the elongate microfossils, and the results demonstrate that biometrical methods are effective in the taxonomy of some Precambrian microfossils.The following new taxa are described:Archaeoellipsoides obesus sp. nov., Archaeoellipsoides conjunctivus sp. nov., Bactrophycus oblongum gen. et sp. nov., Bactrophycus dolichum gen. et sp. nov., Callosicoccus crauros gen. et sp. nov. 相似文献
20.
A. P. Ippolitov 《Stratigraphy and Geological Correlation》2018,26(3):298-332
A representative early Bajocian belemnite assemblage containing four genera and 11 species (two identified in open nomenclature and five new: Eocylindroteuthis weisi sp. nov., E. mariottii sp. nov., E. yarkovi sp. nov., Homaloteuthis volgogradensis sp. nov., and Hastites orphana sp. nov.) is described from a section near the Dubovoi hamlet in the Greater Don Bend area (southern termination of the Don-Medveditsa dislocations). Some members of this assemblage were previously known from the Caucasus; however, it is possible to state the discovery of a Euroboreal belemnite fauna completely new for Russia, previously described only from Central Europe and almost unknown for Eastern Europe. The age of the studied assemblage collected from the lower part of the section, traditionally considered to be Upper Bajocian, corresponds to the Laeviuscula ammonite Chronozone and is the first reliable evidence of marine settings in the Volga Region for the early Bajocian. Two new biostratigraphic units, Beds with Eocylindroteuthis weisi and Beds with H. orphana, are introduced. The former, judging from the occurrences of its characteristic species in Western Europe, has a broad correlative potential. On the basis of datings obtained, the scheme of the formational subdivision of the Middle Jurassic of the Volga Region near Volgograd is revised, and the formerly abandoned Bakhtemir Formation is reinstated as a valid unit. Its total range is reestablished as corresponding to the upper part of the Discites (?)/Laeviuscula Chronozone (lower Bajocian)–Garantiana Chronozone (upper Bajocian). 相似文献