内蒙古东胜中侏罗世延安组孢粉组合

研究了内蒙古东胜罕台川、碾盘梁沟和柳沟 3个剖面中侏罗世孢子花粉化石 34属 6 3种 ,包括 2个新种。基于 10个样品中发现的 386 3粒孢子花粉化石的鉴定和统计 ,建立东胜地区延安组孢粉组合。该组合中蕨类植物孢子有 19属 37种 ,含量占 46 %～ 49% ,最低为 39%。裸子植物花粉略占优势 ,有 15属 2 6种 ,含量为 5 1%～ 5 4% ,最高达 6 1%。与国内外相关资料对比结果表明该孢粉组合的地质时代应属中侏罗世巴柔期。孢粉植物群反映研究区在中侏罗世早期为暖温带或亚热带的暖湿气候     

Early and Middle Jurassic Sporo-Pollen Assemblages of Qiquanhu Coal-Field of Turpan Xinjiang

One hundred and thirteen species of spores and pollens belonging to 58 genera were found from 66 core samples taken from two boreholes of the Early and Middle Jurassic deposits in the Qiquanhu coal-field of the Turpan Basin, Xinjiang have been investigated in this paper. Two of the species are described as new. Three sporo-pollen zones from lower to upper are described as follows: Sporo-pollen zone Ⅰ (equivalent bed: Badaowan Formation) . The pteridophytic spores are slightly more abundant than the gymnospermous pollen in this assemblage. The most abundant spores are Cyathidites minor, C. australis and Undulatisporites pflugii, U. taenus and so on. The second important fern spores are Osmundacidites, Lycopodiumsporites, Apiculatisporis and Duplexisporites. The most important gymnospermous genus is Cycadopites which ranks highest in the assemblage and includes C. nitidus and C. typicus.The other gymnospermous pollen include Classopollis, Pinuspollenites, Protoconiferus Piceites. Besides, there are a few pollen grains of Taeniaesporites and Chordasporites surviving from the Late Triassic in this assemblage. The present assemblage may be compared with the Early Jurassic sporopollen assemblage from the Daling Formation of the North-East Guangxi. Therefore, the Badaowan Formtion may be referred to Early Jurassic in age, probably Early Lias. Sporo-pollen zone Ⅱ (equivalent bed: Sangonghe Formation) In this assemblage the gymnosperms are predominant.Of them, Podocarpidites and Pinuspollenites increase obviously, and Quadraeculina and Protoconiferus are common. Few surviving elements are observed. The most abundant spores are those of Cyathidites, and the particularly abundant pollens are those of Cycadopites, This assemblage may be compared with the Late Lias sporo-pollen assemblage from the Fuxian Formation of the Northern Shangganning Basin. Therefore, the Sangonghe Formation should belong to Early Jurassic, probably Late Lias in age. Sporo-pollen zone Ⅲ (equivalent bed: Xishanyao Formation). The contents of the spores and pollens are almost equal in this assemblage. Cyathidites and Cycadopites are the most important spores and pollen. Osmundacidites and Quadraeculina are common. Neoraistrickia, Lycopodiumsporites and Eucommiidites troedssonii are present. Ancient striate bisaccate pollen disappears. The characteristics of this assemblage show some resemblances to those of the Middle Jurassic Yanan Formation in Chongxin county of Gansu province. So the Xishanyao Formation should belong to Middle Jurassic.     

新疆塔里木盆地中侏罗世塔尔尕组孢粉植物群及地层和古地理意义

新疆塔里木盆地侏罗系分布广泛,在库车凹陷和塔西南区发育最好。目前对库车凹陷的三叠纪和侏罗纪孢粉植物群研究较为深入,而对塔西南区侏罗纪孢粉化石专题研究不多,尚未建立孢粉组合。作者基于塔西南区乌恰中侏罗统塔尔尕组发现的孢子花粉33属48种的研究,建立了塔尔尕组孢粉组合。该组合以掌鳞杉科花粉Classopollis的优势和真蕨目桫椤科孢子Cyathidites的繁盛为特征,并含有丰富多样且颇具侏罗纪色彩的孢子花粉化石类型。该组合与西欧和俄罗斯巴柔期至巴通期孢粉组合以及北美和澳大利亚巴柔期至卡洛夫期孢粉组合可以进行对比;与我国新疆库车恰克马克组、陕西延安直罗组和湖北兴山沙溪庙组等孢粉组合也可对比。根据孢粉学证据,塔尔尕组的时代应属于中侏罗世晚期(巴通期至卡洛夫期)。当前孢粉植物群支持我国侏罗纪南北植物地理区系之西端分界之划分方案,即塔西南乌恰处于界线以南,而库车处于分界以北。     

辽宁义县金家沟义县组砖城子层孢粉组合

辽宁义县金家沟义县组砖城子层的孢粉组合是以无肋双囊类花粉为主(占组合的70%左右),伴以少量Cicatricosisporites,Jugella,Ephedripites,Jiaohepollis等为特征,其基本面貌与北票黄半吉沟义县组尖山沟层的孢粉组合类似,时代同属早白垩世贝利亚斯期,反映温暖湿润的气候环境。     

湖北秭归盆地中侏罗世泄滩组孢粉组合

本文记录了鄂西秭归盆地东缘泄滩组上部21个属36个种的孢粉植物群,其中包括3个新种,讨论了主要属种组合特征和地层延限,根据中侏罗世孢粉植物群组合在国内外的对比,提出泄滩组上部Cyathidites minor-Classopollis-Callialasporites组合的时代属于中侏罗世,这个组合以桫椤科,掌鳞杉科植物的繁盛,和出现大量Cal-lialasporites母体植物为特点,暗示泄滩组上部形成于炎热而干旱的气候环境。     

南京北象山中侏罗世孢粉化石的发现

本文对在南京北象山首次发现的孢粉化石进行了系统的分析研究,共获孢子花粉３７属７７种,其中蕨类植物孢子１５属２３种,裸子植物花粉２２属５４种,组合以高含量的Ｃｌａｓｓｏｐｏｌｌｉｓ为特征。根据孢粉组合特征,其时代应归为中侏罗世。对组合中主要孢粉类型可能的母体植物的生长环境进行分析,推测在中侏罗世的某段时期里,南京地区主要为干旱的气候环境。     

The Sporo-Pollen Assemblage From Fuxian Formantion in Yulin-Hengshan Region,Shaanxi Province

Eighty-eight species of spores and pollen referred to 66 genera including one new species from the Fuxian Formation in Yulin-Hengshan region of Shaanxi province have been studied. The sporo-pollen assemblage may be dividied into two subassemblages. The main characters are described as follows: There are 30.7% of spores of pteridophyta. The pollen grains of gymnospermae arno:rots for 69.3%. Among the spores, those of the genus of Deltoidospora (9.2%), Cyathidites (5.6%) and Undulatisporites (4.6%) are dominant, Among the pollen grains, those of the genus Classopoilis of Chiolepidiaceae is predominant (41.8%) and Chasmatosporites(6.1%) are comparatively abundant. Besides these, there are some other Jurassic common species found in the assemblage. Comparing with the known assemblages of other places, the author considers that the Fuxian Formation belongs to Early Jurassic Lias Series. The lower part of the formation might correspond the Hettangian stage or the Simemurian Stage It: the early Jurassic, the climate should be comparatively humid with flourishing vegetation in the early stage, and hot and arid in the middle-late stage.     

吐鲁番拗陷北部中侏罗世孢粉植物群

报道了新疆吐鲁番拗陷北部勒1、米1 、山1和墩1井中侏罗世孢粉化石52属81种.建立了本区中侏罗世孢粉组合: Cyathidites-Psophosphaera-Cycadopite 组合、 Cyathidites-Quadraeculina-Classopollis 组合和 Cyathidites-Callialasporites-Classopollis 组合.它们分别产自西山窑组、三间房组和七克台组.根据孢粉组合特征及其对比, 认为3个组合的地质时代属阿林-巴通期.经研究表明, 中侏罗世早期的植被是以银杏、苏铁类和松柏类等乔木为主体, 并伴有桫椤科树蕨及紫萁科和卷柏科等草本植物.古气候应属温暖潮湿的亚热带气候.至中侏罗世中晚期, 掌鳞杉科植物在植被中占主导地位, 指示当时的气候趋于干旱.     

天津张贵庄晚二叠世孢粉植物群

天津张贵庄SR13号钻孔原归为石盒子组的地层近顶部发现了丰富的孢粉化石,这一组合兼具上石盒子组和孙家沟组孢粉组合的特征。一方面,它与上石盒子组（特别是其上部）组合有不少共同分子,在蕨类孢子和裸子植物花粉（包括具肋花粉）的含量比例上也可以与之对比,但缺乏一些标志分子。另一方面,在属种组成上,当前组合与已知的孙家沟组合也颇可比较,而且出现了一些中生代色彩的分子。这一组合的揭示与研究有助于提高人们对华北晚二叠世晚期孢粉植物群特征的认识。依据当前组合与已知相关孢粉组合的对比讨论,将其时代定为晚二叠世,并倾向于晚二叠世晚期（对应于孙家沟组）。     

Westphalian Sporo-Pollen Assemblages from the Upper Carboniferous in Zhongwei,Ningxia

About 98 species of fossil spores and pollen referred to 55 genera from the Upper Carboniferous Yanghugou Formation in Zhongwei, Ningxia have been studied. Two sporopollen assemblage zones are recognized in ascending order as follows: 1. Laevigatosporites medius-Cyclogranisporites aureus (MA) zone: This assemblage corresponds to the lower part of the Yanghugou Formation, and is characterized by the predominance of pteridophyfic spores and the relative abundance of gymnospermous pollen. Azonotriletes and monoletes are dominant, while zonates are of importance. The most common species are Leiotriletes spp., Cyclogranisporites aureus Potoni6 et Kremp, Granulatisporites granulatus Ibrahim, Microreticulatisporites concavus Butterworth et Williams, M. nobilis (Welcher) Knox, Triquitrites bransonii Wilson et Hoffmeister, Dictyotriletes bireticulatus (Ibrahim) Smith et Butterworth, Ahrensisporites guerickei (Horst) Potonie et Kremp, Lycospora spp., Crassispora kosankei (Potonie et Kremp) Bharadwaj, Cirratriradites saturni (Ibrahim) Schopf, Wilson et Bentall, Laevigatosporites spp., Columinisporites ovalis Peppers, Florinites junior Potnie et Kremp and Vesicaspora wilsonii (Schemel) Wilson et Venkatachata. This assemblage is comparable with those of the Yanghugou Formation in Baiyantaohai of Inner Mongolia (Yu, 1983), the 8th zone of North China by Gao (1979), the Triquitrites sinani-Cirratriradites saturni (SS) Zone and the Microreticulatisporites nobilis-Florinites junior (NJ) Zone of West Europe, which are considered corresponding to Westphatian A-B in age. 2. Torispora seuris-Punctatisporites hians (SH) zone: This assemblage is equivalent to the upper part of the Yanghugou Formation, and is also characterized by dominance of pteridophytic spores and subdominance of gymospermous pollen. In addition to the most commen species mentioned above, the important taxas in the present assemblage comprise Punctatisporites hians Wang, Gulisporites cochlearius Imgrund, Verrucosisporites kaipingiensis Imgrund, Endosporites globiformis (Ibrahim) Schopf, Wilson et Bentall, Densosporites anulatus (Loose) Smith et Butterworth, D. reticuloides Ouyang et Li, Simozonotriletes labellatus Wang, Torispora securis Balme, Thymospora thiessenii (Kosanke) Wilson et Venkatachala, Pit yos porites west phalensis Williams and Plat ysaccus, Illinites, C ycadopites, etc. This zone compares closely with those of the upper part of the Yanghugou Formation in Hengshanbu (Wang Hui, 1984) and Ordos Basin (Geng, 1985), the Benxi Formation in Shanxi (Liao, 1987; Ouyang and Li, 1980; Gao, 1979), as welll as Torispora securis-T, laevigata (SL) Zone and Thymospora obscura-T, thiessenii (OT) Zone of West Europe. Therefore, the present SH Zone should be referred to Westphalian C-D in age. The Westphalian palynofiora in Zhongwei is dominated by Filicopsida and pteridospermopsida; Sphenopsida and lycopsida occupy the subdominant position, while Cordaitopsida and Coniferopsida do not develop well. This palynofiora indicates a tropical-subtropical warm and humid paleoclimate.     

Paleobotanical remains from the Paleocene–lower Eocene Vagadkhol Formation, western India and their paleoclimatic and phytogeographic implications

A small assemblage of macro- and micro floral remains comprising fossil leaf impressions, silicified wood, spores, and pollen grains is reported from the Paleocene–lower Eocene Vagadkhol Formation (=Olpad Formation) exposed around Vagadkhol village in the Bharuch District of Gujarat, western India. The fossil leaves are represented by five genera and six species, namely, Polyalthia palaeosimiarum (Annonaceae), Acronychia siwalica (Rutaceae), Terminalia palaeocatapa and T. panandhroensis (Combretaceae), Lagerstroemia patelii (Lythraceae), and a new species, Gardenia vagadkholia (Rubiaceae). The lone fossil wood has been attributed to a new species, Schleicheroxylon bharuchense (Sapindaceae). The palynological assemblage, consisting of pollen grains and spores, comprises eleven taxa with more or less equal representation of pteridophytes, gymnosperms, and angiosperms. Angiospermous pollen grains include a new species Palmidites magnus. Spores are mostly pteridophytic but some fungal spores were also recovered. All the fossil species have been identified in the extant genera. The present day distribution of modern taxa comparable to the fossil assemblage recorded from the Vagadkhol area mostly indicate terrestrial lowland environment. Low frequency of pollen of two highland temperate taxa (Pinaceae) in the assemblage suggests that they may have been transported from a distant source. The wood and leaf taxa in the fossil assemblage are suggestive of tropical moist or wet forest with some deciduousness during the Paleocene–early Eocene. The presence of many fungal taxa further suggests the prevalence of enough humidity at the time of sedimentation.     

Petroleum Sporo-Pollen Assemblages and Oil Source Rock of Kuche Seg in Xinjiang

Twenty-eight species (or forms) of fossil pollen and spores referred to 20 genera extracted from the crude oil samples collected from the Kuche Seg of the Talimu Basin in Xinjiang are observed. The conception of the petroleum sporopouen assemblage is further expounded and the classification of the petroleum sporo-pollen assemblage is also tentatively proposed. According to the characteristics of the assemblages, the problem on oil source of the mentioned oil-bearing region is discussed in this paper. The petroleum sporo-pollen assemblage of Jurassic reservoir of Kucbe Seg is composed of Deltoidospora perpusilla, D. gradata, Cyathidites minor, Hymenophyllumsporites deltoidus, Cingulatisporites problematicus, Cibotiumspora paradoxa, Osmundacidites ap., Cycadopites typicus, C. nitidus, Podocarpidites multesimus, Alisporites grandis, Alisporites bilateralis, Parvisaccites sp., Abietineaepollenites microalatus, A. minimus, PinuspoRenites sp., Piceaepollenites sp., etc. These species of spores and pollen have been found from the Jurassic deposits in this region or in the adjacent regions. The petroleum sporo-pollen assemblage only contains the spores and pollen which coincide with those of the reservoir in age. There is not any spore or pollen older or younger than the reservoir. Consequently, it may be referred to a monotonous type of petroleum sporo-pollen assemblage. The petroleum sporo-pollen assemblage of Cretaceous reservoir of this region consists of Deltoidospora perpusilla, Cryathidites minor, Cibotiumspora paradoxa, Schizaeoisporites zizyphinus, Osmundacidites sp., Crcadopites typicus, C. nitidus, Parvisaccites sp., Cedripites cretaceus, Abietineaepollenites microalatus, A. minimus, Pinuspollenites sp., etc. All these species distribute either in the Jurassic deposits or in the Cretaceous deposits in this region or in the adjacent regions. The distribution of Schizaeoisporites zizyphinus and Cedripites cretaceus is usually limited to the Cretaceous deposits. Both the Cretaceous species and the Jurassic species are comprised in the assemblage, so it may be referred to a composite type of petroleum sporo-pollen assemblage. The petroleum sporo-pollen assemblage of Tertiary reservoir comprises Deltoidospora perpusilla, Cyathidites minor, Cibotiumspora paradoxa, Schizaeoisporites zizyphinus, Poly-podiaceaesporites sp., Cycadopites nitidus, Podocarpidites multesimus, Parvisaccites sp., Abietineaepollenites mininus, Pinuspollenites labdacus, Piceaepollenites alatus, Cedripites ovatus, Ephedripites fusiformis, Quercoidites microhenrici, Chenopodipollis multiporatus, C. microporatus, Artemisiaepollenites sdlularis, etc. Besides the Tertiary pollen and spores, the assemblage contains the Jurassic species and the Cretaceous species, and therefore it belongs to a composite type of petroleum sporo-pollen assemblage. The monotonous type of petroleum sporo-pollen assemblage reflects that the oil source rock is coincident with the reservoir rock in age, and the composite type of petroleum sporopollen assemblage shows that the oil source rock is generally older than the reservoir rock. Based on the investigation of the petroleum sporo-pollen assemblages, the oil source rock of the Kuche Seg is considered to be Jurassic Period in age, and the Lower Jurassic Yangxia Formation and the Middle Jurassic Kuzilenuer Formation are considered to be favorable source rock. The conclusion is supported by the result of the organic geochemical investigation.     

山东滕县煤田石炭纪、二叠纪孢粉植物群及古气候

根据前人在原位孢子方面已积累的大量资料,并参考现代孢子花粉形态研究成果,大致推测了本区石炭-二叠纪分散孢子花粉的大多数属的植物亲缘关系。通过已建立的含煤地层孢粉组合带推测相应时期的古植被类型,并与前人有关地质时期及地层的大植物化石带进行了对比,不仅验证了各地质时期植被的兴起、发展、繁盛以及衰退绝灭的历史过程,更大意义上将微体形态的孢子花粉与宏观上的植被进行了对比归类,从而使得对研究区晚古生代含煤地层的古植被的形态面貌有了更直观的了解。最后,利用孢粉分析恢复相应地质时期的古气候。     

吉林农安地区晚白垩世嫩江组孢粉化石组合及其古气候记录

沈家屯剖面位于松辽盆地东南部吉林省农安地区,富含孢粉化石,岩性以泥岩为主,夹粉砂岩,属于嫩江组三、四段.本文通过对沈家屯剖面孢粉化石的分析,识别出Aquila pollenites-Dictyotriletes-Rugubivesiculites,Schizaeoisporites-Classopollis-Beaup...     

辽河盆地大民屯凹陷沈249井早白垩世九佛堂组孢粉组合

沈249井九佛堂组孢粉材料是目前所知辽河盆地孢粉类型最丰富、数量最多且保存最完好,可确定63属,包括蕨类植物孢子40属和裸子植物花粉23属;根据孢粉组合特征,可称其为Cicatricosisporites Concavissimi sporites Classopollis孢粉组合,具有裸子植物花粉相对含量明显较高、分异性较低,而蕨类植物孢子分异性明显较高、相对含量较低的特点;该组合与辽西九佛堂组、内蒙古二连盆地赛汉塔拉组一段的孢粉组合具有很强的一致性。本文资料可弥补辽河盆地九佛堂组孢粉组合的空白,并为深入认识我国北方区九佛堂组沉积时期植物群特征提供重要的帮助。     

Early Cretaceous Palynofloras from Tarim Basin,Xinjiang

One hundred and eight species of fossil spores and pollen referred to 55 genera found from the Lower Cretaceous Kapushaliang (Kizilsu) Group in the Tarim Basin of Xinjiang have been studied in this paper. The Kapushaliang Group may be divided into the Yageliemu Formation, the Shushanhe Formation and Baxigai Formation in ascending order. The Yageliemu palynoflora is characterized by the predominance of gymnospermous pollen, the relative abundance of pteridophytic spores and the absence of angiospermous pollen. Coniferae is dominant, while Lygodiaceae and Schizaeaceae are important in the flora. The most common species of palynomorphs are Todisporites minor, Cicatricosisporites dorogensis, C. australiensis, Lygodiumsporites subsimplex, Schizaeoisporites cretacius, S. zizyphinus, S. certus. Cibotiumspora paradoxa, Cyathidites australis, C. minor, Biretisporites potoniael, Cycadopites minimus, Pseudowalchia hiangulina, Parvisaccites radiatus, Podocarpidites multesimus, P. canadensis, Alisporites bilateralis, Cedripites cretaceus, C. canadenris, Abietineaepollenites microalatus, Clarsopollis classoides, C annulatus, C. xinjiangensis (sp. nov.), Ephedripites multicostatus, E. tarimensis (sp. nov.), etc . The palynoflora is comparable with those of the lower part of the Lower Xinminbu Formation in northwestern China and the lower part of the Lower Mannville Formation in western Canada, which is considered corresponding from Berriasian to Valanginian in age. The Shushanhe palynoflora is also characterized by dominance of gymnosperms and subdominance of pteridophyta. Some primitive angiospermons pollen grains are found in the upper part of the formation. In addition to the most common species of the above mentioned palynoflora, the important species in the present palynoflora comprise Cicatricosisporites potomacensis, C. orbiculatus, C. subrotundus, Concavissimisporites punctatus, C. verrucosus, C. globosus, lmpardecispora apiverrucata, Trilobosporites crassus, T. trioreticulosus, Pilosisporites verus, P. trichopapillosus, Klukisporites pseudoreticulatus, Verrucosisporites obscurilaesuratur, Converrucosisporites saskatchewanensis, Foraminisporis wonthaggiensis, Cingulatisporites valdensis, C. ruginosus, Jiaohepollis verus, Pityosporites constrictus, etc. More than 40 in dicative species of Early Cretaceous occur in the assemblage. The palynoflora compares clcsely with those of the middle part of the Lower Xinminbu Formation and the Quartz Sand Member of the Lower Mannville Formatton. It is suggested that the Shushanhe Formation should belong to Hauterivian of Barremian in age. The Baxigai palynoflora is basically similar to the Shushanhe palynoflora. But the palynoflora shows an obvious increase in abundance of lygodiaceous spores and angiospermous pollen accompanied by a great reduction of Classopollis and Ephedripltes. Most of the Early Cretaceous species occurring in the above mentioned palynofloras are present. In addition, some Cretaceous species recorded from Aptian and Albian Stages in Europe, North America and Australia, such as Trilobosporites tribotrys, T. trioreticulosus, Coptospora paradoxa, Camarozonosporites insignis, Crybelosporites punctatus, etc., appear in the assemblage. In comparison with the microfloras of the upper part of the Lower Xinminbu Formation, the Upper Mannville Formation and the lower part of the Lower Colorado Group, the Baxigai Forma- tion should be referred to Aptian to Albian in age. Judging from the palynofloras, the early Cretaceous palaeoclimate in the basin should belong to the arid or semi-arid type of the subtropic zone. However, from Barremtan through Albian the climatic conditions might appear relatively wet.     

四川宣汉晚三叠世孢粉组合及其古植被与古气候意义

对四川盆地东北缘宣汉七里峡剖面须家河组进行了详细的孢粉学研究,发现丰富的孢粉化石,共计59属113种,其中包括蕨类植物孢子35属62种,裸子植物花粉22属47种,苔藓类植物孢子1属3种,以及藻类化石1属1种。据此建立一个孢粉组合,命名为Dictyophyllidites-Lunzisporites-Chasmatosporites组合(简称DLC组合),并进一步分为上、下两个亚组合。根据孢粉组合内一些重要分子的地质时代延限及与国内外有关孢粉组合的对比,提出其地质时代属于晚三叠世诺利期—瑞替期(Norian—Rhaetian)。该孢粉植物群反映了一个以蕨类植物的真蕨类、石松类和裸子植物的松柏类和苏铁类群等占主导且较为繁盛的植被面貌,揭示出温暖潮湿的亚热带—热带气候环境。     

新疆准噶尔盆地西北缘早侏罗世三工河组孢粉组合

本文报道了采自新疆准噶尔盆地西北缘红山咀区拐114井三工河组的孢粉化石,33属58种。通过对孢粉组合的系统分析研究,认为三工河组的地质时代应归为早侏罗世。     

新疆鄯善照壁山克拉玛依组孢粉组合

本文研究了新疆鄯善照壁山沟口克拉玛依组顶部的孢粉化石,共鉴定孢粉４６属７０种,命名为Ｐｕｎｃｔａｔｉｓｐｏｒｉｔｅｓ－Ａｒａｔｒｉｓｐｏｒｉｔｅｓ－Ｔａｅｎｉａｅｓｐｏｒｉｔｅｓ－Ｐａｒａｔａｅｎｉａｅｓｐｏｒｉｔｅｓ组合。根据组合主要分子的时限及其含量变化,以及与有关已知时代孢粉组合进行对比,鉴定其其他质时代为中三叠世。根据孢粉植物群反映当时为温湿的气候特征。     

Petroleum Sporo-Pollen Assemblages and Oil Source Rock of Yumen Oil bearing Region in Gansu

Twenty-six species (or forms) of fossil pollen and spores referred to 24 genera extracted from the crude oil samples collected from the Yumen oil-bearing region in West Gansu are observed and the definition of the petroleum sporo-pollen assemblage is given by the authors. On the basis of palynological investigation, the oil source rock of this oil-bearing region is tentatively discussed in this paper. The fossil pollen and spores found from the Tertiary petroleum in this region may be divided into two groups, because they are extremely different in fossilized state. The group of spores and pollen with higher fossilized state is mainly consisted of Schizaeoisporites zizyphinus, Gibotiumspora paradoxa, Monosulcites minimus and Bennettiteaepollenites sp. The other group comprises Pinus, Picea, Ephedra, Potamogeton, Lilium, Ulmus, Chenopodium, Nymphaea, Eutrema, Lens, Nitraria, Tamarix, Achillea, Artemisia, Solidago, Bidens, Graminidites, Cypheraceaepollis, etc. The above mentioned petroleum sporo-pollen assemblage of the tertiary oil reservoir rock is a gathering of fossil pollen and spores brought from the Lower Cretaceous deposits and the tertiary deposits respectively. The appearance of the Early Cretaceous pollen and spores bearing in the black shales of the Lower Xinminbu Formation in the tertiary petroleum may be considered to be a result of petroleum migration. And it reflects that the oil source rock might belong to Early Cretaceous Series. The fossil pollen and spores extracted from the Early Cretaceous petroleum in this region contain merely Schizaeoisporites zizyphinus, Monosulcites minimus, Bennettiteaepollenites sp., Psophosphaera, etc. The tertiary pollen and spores are completely absent there. So it indicates that both the oil source rock and the oil reservoir rock should belong to the fossil-bearing Lower Xinminbu Formation. In addition, there are some pollen of Monosulcites and Psophosphaera in the petroleum reserved in the fissures of the Silurian metamorphic rock. They are also probably brought from the Lower Xinminbu Formation by oil and gas in the process of their migration. In any case, judging from the pollen and spores found from the crude oil, the oil source rock of this oil-bearing region is deduced to be the black shales of the Lower Xinminbu Formation referred to as Early Cretaceous Epoch.