Palaeogene Biostratigraphic Characteristics of Red Basins In Western Henan and Its Adjacent Areas, With an Outline of Palaeogene Palaeobiogeographic Provinces of China

This article is a preliminary summary of Paleogene biostratigraphy of the Liguanqiao, Tantou andYuanqu basins, with a new proposal for Paleogene paleobiogeographic provinces of China. On the basis of asynthetic analysis of the geological data, characters of the mammalian assemblages and their comparisons withother corresponding faunas, a new scheme on Paleogene biostratigraphic subdivision of the basins has been putforward here. Based on differences of biostratigraphic sequences, characteristics of mammalian assemblagesand directions of faults controlling Paleogene basins in China, six Paleogene paleobiogeographic provinces ofChina have been proposed in this paper, that is: Tianshan-Yinshan-Tumen Province; Tarim-North China Prov-ince; Kunlun-Qinling Province, Yangtze Province, Nanling and Southeastern Coastal Province, Qinghai andTibet Province.

甘肃平凉上奥陶统牙形石和笔石生物地层

在经典的平凉官庄剖面附近的一个采石场内,出露一套新鲜的奥陶纪地层。为了确定其精确层位,在灰岩和页岩层段分别密集地采集了牙形石和笔石样品并获得丰富的化石标本。鉴定结果显示,牙形石动物群存在不同生物地理区化石属种混生的现象,其中北美中大陆型的以Belodina compressa(Branson et Mehl,1933)、Erismodus typus Branson et Mehl,1933和Plectodina aculeatus(Stauffer,1930)等属种为代表,北大西洋型的以Pygodus anserinus Lamont et Lindstr9m,1957、Periodon aculeatus Hadding,1913和Protopanderodus varicostatus(Sweet et Bergstrom,1962)等属种为代表。Belodina compressa系北美中大陆生物地理区重要的且常见的带化石,在本次获得的所有牙形石属种中其指示的层位最高。据此,判定研究剖面的牙形石动物群属于Belodina compressa牙形石带。本次研究的笔石动物群以带化石Climacograptus bicornis(Hall,1847)的出现为主要特征,与之伴生的其它重要的属种包括Nemagraptus gracilis(Hall,1847)、Normalograptus brevis(Elles et Wood,1906)、Dicranograptus brevicaulis Elles et Wood,1904以及Archiclimacograptus meridionalis(Ruedemann,1947)等,共计14属20种。显然,该动物群对应Climacograptus bicornis笔石带。Belodina compressa牙形石带和Climacograptus bicornis笔石带同为晚奥陶世桑比期全球广布性的重要的化石带。这表明两类生物地层研究结果高度吻合、统一,研究剖面的地层时代为晚奥陶世桑比期晚期,对比官庄剖面(标准剖面)平凉组的顶段。不同生物地理区牙形石属种混生的现象,反映了研究区在这一地质历史时期发生过令水体加深、水温下降的古构造活动事件。

Reineckeiidae (Ammonoidae) Family of the Dalichai Formation in Damghan Area (East Alborz), Iran

The present study is concerning the systematic descriptions of the Middle Jurassic (Callovian) ammonite fauna from the Damghan Area (eastern Alborz) and contains a rather rich ammonite fauna. The described ammonites come from the Middle part of the Dalichai Formation, consisting of an alternation of green marl, grey limestone and marly limestone. In this research, the biostratigraphy of these rocks is discussed with special emphasis on the abundant ammonite fauna (Reineckeiidae family). Altogether, 74 specimens of ammonites belonging to 14 species, 3 genera, 3 sub genera from Reineckeiidae family are described. Palaeobiogeographically the ammonite fauna is closely related to that of the sub-Mediterranean Province of the northwestern Tethys. The ammonites represent four zones, i.e. Rehmannia (Loczyceras) cf. segestena (Anceps Zone), Rehmannia (Loczyceras) reissi (Anceps Zone), Rehmannia (Loczyceras) rehmanni (Anceps Zone), Rehmannia (Loczyceras) sequanica densicostata (Coronatum Zone), Reineckeia (Tyrannites) convexa (Gracilis Zone), Reineckeia (Tyrannites) pictava (Gracilis Zone), Reineckeia (Reineckeia) anceps anceps (Anceps Zone), Reineckeia (Reineckeia) anceps elmii (Anceps Zone), Reineckeia (Reineckeia) cf. fehlmani (Anceps Zone), Reineckeia (Reineckeia) nodosa (Athleta Zone), Collotia cf. multicostat (Anceps Zone), Collotia cf. gaillardi (Coronatum Zone), Collotia cf. oxyptychoides (Athleta Zone), Collotia cf. collotiformis (Athleta Zone).

新疆乌鲁木齐地区上石炭亚系祁家沟组介形类及其古环境和古地理意义

新疆乌鲁木齐地区上石炭亚系祁家沟组地层出露较完整,沉积序列清晰,古生物化石丰富,但一直以来对祁家沟组的时代多有争论,且介形类研究薄弱。笔者在新疆乌鲁木齐地区祁家沟剖面上石炭亚系祁家沟组中鉴定出的介形类共计11属19种,并系统研究了这些介形类的组合面貌、地层分布,探讨了其古环境和古地理意义。结果表明:(1)根据介形类的组合面貌推断,祁家沟剖面祁家沟组的时代应为晚石炭亚纪莫斯科期—卡西莫夫期;(2)祁家沟组介形类生态类型属于古足目类和光滑速足目类的混合集群,符合构造活动区域的介形类OA1-OA3组合特征;(3)根据介形类的生态组合变化以及沉积学的证据,推断祁家沟剖面祁家沟组整体为滨、浅海沉积,存在海退序列;(4)祁家沟组介形类面貌与同时期的塔里木、准噶尔、中天山以及俄罗斯乌拉尔地区等产出的介形类最为相近,与北美、西欧和华北等板块的介形类也较为相似,表明晚石炭亚纪准噶尔、塔里木等块体聚集,并且距离劳俄大陆较近,所以其可与欧洲、北美板块的介形类进行属种交流。研究结果不仅进一步丰富了祁家沟组的化石材料,也对探索古亚洲洋演化特征和区域矿产开发具有重要的意义。

兴蒙—新疆北部及邻区早石炭世古生物地理区系

中国兴蒙—新疆北部及邻区早石炭世地层十分发育，动植物化石丰富。根据生物群综合分析，将该研究区归入哈萨克斯坦—西伯利亚域和特提斯域，并进一步划分为３个省，８个亚省。西伯利业省以管孔贝大量发育为特征，缺少大长身贝类，珊瑚不甚发育，植物少见，为安加拉植物群；哈萨克斯坦—蒙古—兴安省以管孔贝类和大长身贝类共同发育为突出特征，珊瑚较发育，但分区特征不明显，并有大量异珊瑚类，植物为安加拉植物群；塔里木北缘—西秦岭省以南方型生物群大量发育为主要特征，大长身贝类最为发育，缺少管孔贝类，珊瑚数量十分丰富，并有假乌拉珊瑚大量发育，植物以华夏植物群为主。早石炭世古生物地理分区与板块关系密切，晚泥盆世末，西伯利亚板块南移，与哈萨克斯坦板块汇聚，到早石炭世早、中期，两大板块基本上处于相近似的古生物地理环境，与此同时，塔里木板块逐渐北移，与哈萨克斯坦板块海水相通，致使哈萨克斯坦板块广大海域出现南、北动物群混生现象。早石炭世末，三大板块海域相连，除各地沉积和构造古地理环境尚有差异外，中石炭世开始，腕足类，类及珊瑚等动物群均显示出明显的一致性。

青海玛多县长石头山中二叠世■类的发现及其地质意义非

青海玛多县长石头山广泛出露一套岛礁灰岩,此前由于在本区未发现大量的■类化石,前人认为其归属于阿尼玛卿小区,这次在岛礁灰岩中发现了11属19种■类化石,在此基础上建立了两个■带,自下而上为Parafusulina带和Neoschwagerina margaritae带。由此确定树维门科组岛礁灰岩时代为中二叠世茅口亚世孤峰期。此外,该区■类化石生物群面貌与华南地区■类化石生物群面貌极为相似,因此在中二叠世时该区属于特提斯区。根据■类化石的分布特点及其面貌特征,将长石头山岛礁划归于巴颜喀拉小区(古生物地理分区)。