“元谋组”及“元谋动物群”含义的厘定   总被引：5，自引：1，他引：5  

程捷  刘学清  岳建伟  王海芝  张西娟 《地层学杂志》2002,26(2):146-150

讨论了云南元谋盆地的“元谋组”,“元谋动物群”的含义和时代。元谋组应只指钱方等人的“元谋组”的第四段地层 ,相应的动物群称为“元谋人”动物群。钱方等人的第三段地层应称甘棠组 ,其动物群名称为甘棠动物群。甘棠组和元谋组的时代分别为早更新世早期和晚期。  相似文献   

甘肃省东乡族自治县龙担黄土底部新发现的哺乳动物群初步报道   总被引：4，自引：3，他引：4       下载免费PDF全文

邱占祥  王伴月  邓涛  倪喜军  王晓鸣 《第四纪研究》2002,22(1):33-38

龙担哺乳动物群发现于甘肃省东乡族自治县的早更新世黄土底部。此前我国早更新世的哺乳动物化石大多发现于河-湖相地层中,在黄土中极少发现,而且主要在六盘山以东。在龙担哺乳动物群中还发现了灵长类化石,这在我国西北地区尚属首次。龙担哺乳动物群产于黄土底部约30m的地层中,最低的层位距“底板”(积石组砾岩)仅约3m。化石相当丰富,其中有不少新的种类。目前已发现的化石共21种,大体可以分为3类:1)与泥河湾哺乳动物群相同或很接近的;2)与泥河湾哺乳动物群相比,在进化水平上稍低,因而可能代表较早地质时代的;3)在泥河湾哺乳动物群中没有发现过的。龙担哺乳动物群的地质时代可能比泥河湾者稍早,可能约2MaB.P.。其组成倾向于表明,当时该地区周围还有相当面积的森林覆盖。  相似文献   

辽宁东部中寒武世徐庄期三叶虫动物群     

昝淑芹 《吉林大学学报(地球科学版)》1992,(3)

详细研究了辽宁东部中寒武世徐庄期的三叶虫动物群,包括45个种,分属于23个属和2个亚属.在此基础上,将中寒武统徐庄阶划分了7个生物带,其中新建生物带1个,新划分出生物带2个,并与有关地区进行了对比.  相似文献   

Physical, chemical and faunal characteristics of a perennial stream in arid northern Oman     

Reginald Victor  Abdullah I. S. Al-Mahrouqi 《Journal of Arid Environments》1996,34(4):465-476

A study of a 1·5 km stretch of a perennial stream in arid northern Oman describes the physical, chemical and faunal characteristics of riffles, runs and pools. Air temperature seems to influence invertebrate recruitment. Flooding is the most important catastrophic event that alters the physical and chemical environment. Current velocity and substrate composition are also probable factors affecting the community structure. All other chemical conditions except nitrate (–N) were significantly similar in all biotopes. Three vertebrate and 33 invertebrate taxa were recorded. The low faunal diversity is a reflection of a physically controlled system.  相似文献   

Comparisons between the ichthyofaunas of a temperate lagoonal-like estuary and the embayment into which that estuary discharges     

I. C. Potter  D. Tiivel  F. J. Valesini  G. A. Hyndes 《International Journal of Salt Lake Research》1996,5(4):337-358

Leschenault Estuary consists of a large lagoonal-like water body, which opens into Koombana Bay through a short and deep entrance channel at its southern end. Since the only major tributary discharges into the estuary opposite the entrance channel, much of the freshwater discharge in the winter passes directly out to sea. Consequently, during the year of the present study, the mean monthly salinities in the main body of the estuary remained above 20 per mil. This presumably accounts for the fact that the ichthyofaunal composition in the shallows of the estuary did not undergo the type of marked changes that are exhibited in other south-western Australian estuaries, in which salinities often fall below 10 per mil in winter. Despite the maintenance of high salinities in Leschenault Estuary and a close proximity to Koombana Bay, the estuary contained a far greater density and markedly different species composition of fish than that found in that marine embayment. This difference reflected, in part, the high abundance in Leschenault Estuary of some species whose entire life cycle is confined to estuaries,e.g. the atherinidsAtherinosoma elongata andLeptatherina wallacei and the gobiesPseudogobius olorum andAfurcagobius suppositus, and the fact that the juveniles of several marine species,e.g. Hyperlophus vittatus, Sillaginodes punctata, Mugil cephalus andGymnapistes marmoratus were also largely or entirely restricted to the estuary. In contrast,Lesueurina platycephala, which was by far the most abundant species in Koombana Bay, was absent in the estuary. Furthermore, the relatively protected region of Koombana Bay contained a greater density and different composition of fish than the more exposed region of this embayment. This reflected the greater use that was made of the protected region as a nursery area by certain marine species,e.g. Aldrichetta forsten andSillago bassensis. Our data, when taken in conjunction with those collected on the fish fauna in other south-western Australian estuaries, demonstrate that, within this geographical region, some fish species are specifically adapted to the estuarine environment, and that certain marine species apparently have a strong preference for using the highly protected and productive waters of this type of environment as a nursery area.  相似文献   

Protection of tropical barrier beaches: a potential remedial measure     

J. Sundaresan 《Environmental Geology》1993,22(3):272-275

Chronic erosion is found along structurally protected beaches of Kerala, viz., Narakkal (17.8 m³/m¹) and Munambam (80.36 m³/m^–1). The textural characteristics of these beaches are discussed. Observations on the horizontal and vertical distribution of the intertidal fauna of Narakkal beach are presented. The feasibility ofSeaevola taccada as a vegetative beach protective measure is elucidated. The impact of anthropogenically-climatically induced coastal hazards such as sea level rise (SLR) on a typical barrier beach of Kerala is depicted. An alternative beach protective measure to curtail the impact of sea level rise on sandy and atoll beaches of a tropical region is highlighted.  相似文献   

狼鳍鱼（Lycoptera）岩层的时代归属   总被引：23，自引：3，他引：23  

李佩贤  苏德英 《地质学报》1994,68(1):86-100

在燕辽区，狭义的大北沟组产Ｎｅｓｔｏｒｉａ－Ｋｅｒａｔｅｓｔｈｅｒｉａ群，Ｅｏｐａ－ｒａｃｙｐｒｉｓ－Ｌｕａｎｐｉｎｇｅｌｌａ－Ｄａｒｗｉｎｕｌａ组合等化石，白旗组的Ｒｂ－Ｓｒ等时线年龄为１４５．２Ｍａ，以及完整的层序关系均证明狼鳍鱼岩层履于上侏罗统之上。热河动物群包括原始Ｔｒｉｇｏｎｉｏｉｄｉｄｓ群，Ｅｏｓｅｓｔｈｅｒｉａ群，Ｌｙｃｏｐｔｅｒａ群…以自身的演化规律阐明其属于白垩系的类群。Ｅｏｓｅ  相似文献   

福建雁石二叠—三叠系界线地层及动物群   总被引：1，自引：0，他引：1  

吴顺宝  陈贵英  刘馨兰 《地球科学》1988,(5)

雁石二叠—三叠系界线地层及动物群可作为碎屑岩沉积区的代表性剖面来研究。首次发现和研究了本剖面的粘土岩层,鉴定为伊利石—蒙脱石粘土岩,它能和广布华南的界线粘土岩层对比,并与当时的火山活动有关。界线附近较丰富的动物群的采集及地球化学特征的测试,提高了界级划分精度,揭示生物更替规律,证明两系之间为整合的接触关系。  相似文献   

新发现的周口店晚更新世洞穴地层及哺乳动物群研究     

田明中  曹伯勋  袁铃声  赵志中  陈莲芳  涂丽娟 《海洋地质与第四纪地质》1994,(1)

本文依据新发现的晚更新世洞穴地层剖面，进行了年代学及哺乳动物化石方面的研究。年代学综合测定结果为距今１２～１．９万年，这是周口店地区迄今发现的最为完整的晚更新世洞穴地层剖面，根据堆积物中所含的哺乳动物化石特征，进行了生态、种类方面的研究，建立了一个新的哺乳动物群─—东岭子动物群。  相似文献   

连云港疏浚工程对底栖动物影响的调查研究     

陈德昌  唐寅德  张勇  马宏广 《海洋科学进展》1991,(3)

由于港口扩建工程,连云港地区每年有数百万立方米的泥土集中排抛于局部海域。废弃土在排抛区内形成淤积并影响着底栖动物的栖息环境。作者于1986年和1988年在连云港海域进行了底栖动物采样,调查得出了生物量和栖息密度的分布概况。结果表明:疏浚工程影响着底栖动物的生存,但其影响范围是局部的。  相似文献