山东省东北部车镇凹陷古近系沙河街组滨浅湖沉积中的遗迹群落

济阳坳陷车镇凹陷古近系沙河街组滨浅湖沉积中产有十分丰富的动物遗迹化石,共鉴定出遗迹属 10个,未定属 1个,其中遗迹种 7个,未定种 4个。遗迹化石包括Beaconitesantarcticus, Beaconitescapronus, Planolitesmontanus, Macaronichnussegregatis, Taenidiumbarretti, Cochlichnusanguineus, Gordiasp., Skolithossp., Ophiomorphanodosa, Sagittichnussp.和Favreinasp.。这一遗迹化石群落主要是无脊椎动物的进食迹、觅食迹、居住迹和停息迹,其中大部分呈全浮痕保存,少数呈上浮痕保存,并形成于经常干旱和周期性泛滥的滨浅湖沉积环境中。该群落可识别出两个遗迹化石组合,即 1)Beaconites Taenidium组合,它主要产自干旱气候条件下的滨浅湖沉积环境;2)Sko lithos Ophiomorpha组合,它代表了丰水期水体能量相对较高的滨湖沉积环境。     

川中-川南地区上三叠统滨浅湖沉积中的遗迹化石

川中-川南地区上三叠统滨浅湖沉积中产有丰富的动物遗迹化石,识别为3大类6属8种,包括Sko-lithos linearis,S.verticalis,Ophiomorpha nodosa,Planolites beverleyensis,P.montanus,Palaeophycus tubularis,Taenidiumsatanassi和Cochlichnus anguineus,另外,逃逸构造也很发育。这些遗迹化石主要是无脊椎动物的居住迹、进食迹和觅食迹,大多为全浮痕和上浮痕保存。根据遗迹化石的组合特征及其沉积环境,可识别出3个遗迹组合:1)Skolithos linearis遗迹组合,主要由长的垂直或高角度倾斜的悬食居住潜穴构成,反映高能的砂质滨湖环境;2)Cochlichnus-Planolites遗迹组合,主要由进食迹和牧食迹组成,形成于低能的滨湖沼泽环境;3)Skolithos-Planol-ites遗迹组合,以居住潜穴和进食潜穴为主,遗迹化石的丰度较高,代表潮湿气候条件下的浅湖环境。根据生物扰动的分布及扰动强度,浅湖中可识别出两类扰动类型,即1)砂泥边界扰动,扰动主要发育于砂泥交界处,代表了浅湖下部环境;2)薄砂层扰动,扰动主要发育于薄砂层中,主要出现于浅湖中下部沉积中。     

河南西峡盆地上白垩统寺沟组遗迹化石及其沉积环境

西峡盆地上白垩统寺沟组岩性以紫红色薄层粉砂质泥岩、灰黄—灰绿色厚层状粉砂岩、细砂岩为主,夹灰黄、灰白色厚层状含砾砂岩及中粗砂岩。本次工作发现遗迹化石11属19种:包括Archaeonassaisp.,Arenicolites isp.,Cylindricumisp.,Beaconites antarcticus,B.capronus,B.coronus,Gastruichnus xixiaensis,Naktodemasis isp.,Palaeophycus tubularis,P.heberti,P.sulcatus,P.striatus,Planolites beverleyensis,Planolitesisp.,Scoyenia gracilis,Skolithos verticalis,Skolithos isp,Taenidium irregularis,T.serpentinum和似逃逸迹。根据遗迹化石的产状及其围岩的沉积特征,建立了Beaconites-Palaeophycus遗迹组合和Taenidium-Scoyenia遗迹组合,分别代表了曲流河和浅水湖泊(河漫湖泊)沉积环境中遗迹化石的组成特征。基于岩性特征、沉积构造和遗迹化石组成特征的综合分析,划分出五种沉积序列类型,揭示了寺沟组曲流河边滩、泛滥平原、洪流砂体与河漫湖泊在沉积过程中的变化和相应的遗迹群落变化特征。结合寺沟组中遗迹化石分布及组合特征,Beaconites-Palaeophycus遗迹组合和Taenidium-Scoyenia遗迹组合可归属于Scoyenia遗迹相。     

四川龙门山地区下泥盆统平驿铺组的遗迹化石

四川龙门山甘溪剖面下泥盆统平驿铺组的滨浅海相地层中赋存无脊椎动物遗迹化石,可识别出居住迹、停息迹、觅食迹3大类,鉴定为11属,包括Arenicolites,Chondrites,Cylindrichnus,Diplocraterion,Palaeophycus,Planolites,Phycodes,Rhizocorallium,Rusophycus,Skolithos和Thalassinoides。根据遗迹化石特征及其沉积环境,可识别出5个遗迹组合:1)Planolites-Palaeophycus遗迹组合,主要由觅食迹组成,指示低能的砂质近滨环境;2)Rusophycus-Phycodes遗迹组合,主要是觅食迹和停息迹,形成于低能的近滨环境;3)Chondrites-Palaeophycus遗迹组合,主要是居住迹和觅食迹,反映了贫氧低能的近滨下部环境;4)Skolithos-Cylindrichnus遗迹组合,主要由居住迹组成,形成于高能的前滨环境;5)Skolithos-Diplocraterion遗迹组合,主要为居住迹和觅食迹组合,反映了低能、食物丰富的近滨上部环境。     

山东济阳坳陷古近系沙河街组深水湖沉积中的遗迹化石

山东济阳坳陷古近系沙河街组深水湖沉积地层主要由深灰色、褐灰色泥岩、油泥岩、泥灰岩和石灰岩以及岩盐组成,浊流沉积发育。已发现深水型遗迹化石有12个遗迹属14个遗迹种,包括3个新遗迹属6个新遗迹种。根据这些遗迹化石的组成与分布特征及其围岩的沉积特征,可以划分出2种不同沉积环境下的遗迹化石群落,即(1)Mermoides-Neonereites遗迹群落,主要由觅食迹(Fodinichnia)和牧食迹(Pascichnia)组成,常见分子有Mermoides chezhenensis,Mermoides latiusculus,Neonereites uniserialis,Hel minthoidichnitescf.tenuis,Hel-minthopsis abeli,Pilichnus lacustris,Multilagueichnus lingpanensis,Cochlichnus anguineus,Gordiaichnosp.,Palaeophycus tubularis和Planolites beverleyensis等,它们被解释形成于半深水湖或较深水湖沉积环境;(2)Semi-rotundichnus遗迹群落,以半圆形、小碟形牧食迹为其特征,典型组成分子有Semirotundichnus dongyingensis,Pa-tellarisichnus boxingensis和Neonereites uniserialis等,它们均产生于深水湖沉积环境。     

内蒙古乌达煤田早二叠世山西组湿地植被群落演替序列

基于对内蒙古乌达地区早二叠世山西组2号煤相邻地层的野外工作,系统采集植物化石12属、14种。根据沉积环境及植物古生态学分析,识别出生长于该地区早二叠世三角洲平原环境下的植被群落演替序列,包括由早及晚5个群落,即:1)Lepidodendron incertum Sze et Lee群落,代表最初开始形成2号煤层的植被;2)Lepidodendron incertum-Lepidodendron posthumii Jongm.et Goth.群落,反映2号煤下段煤层在停止成煤作用之前的沼泽植被;3)Stigmaria ficoides(Sternb.)Brongn.-Calamites suckowii Brongn.群落,反映泛滥平原上碎屑沼泽与河流之间的广大湿地所生长的植被;4)Lepidodendron incertum-Calamites suckowii群落,代表该区泛滥平原上碎屑沼泽植被;5)Pecopteris taiyuanensis Halle-Emplectopteris triangularis Halle-Taeniopteris serrulata Halle群落,反映天然堤及河流上游泛滥平原中的植被生态群落。植物群落整体面貌为典型的华夏植物群(如织羊齿、大量的带羊齿以及东方鳞木类)。当前群落演替序列反映了二叠纪华夏植物群成煤向碎屑景观的演替状况,以及华夏区成煤植被的稳定性。     

山西兴县中奥陶统马家沟组五5亚段遗迹化石组合及其古环境意义

鄂尔多斯盆地东缘关家崖剖面奥陶系马家沟组五5亚段地层中保存大量无脊椎动物遗迹化石,可识别出居住迹、牧食迹、觅食迹三大类,共7个遗迹属、14个遗迹种,分别是Arenicolites isp.,Cylindricumisp.,Helminthopsis abeli,Helminthopsis isp.1,Helminthopsis isp.2,Lorenziniaisp.,Planolites isp.,Planolites beverleyensis,Planolites montanus,Teichichnus rectus,Thalassinoides isp.1,Thalassinoides isp.2,Thalassinoides isp.3,Thalassinoides isp.4。根据遗迹化石特征及其沉积环境,可划分3个遗迹组合:1、Helminthopsis-Planolites组合,该组合以觅食迹为主,部分为居住迹,出现在潮间带和潮下带;2、Thalassinoides-Teichichnus组合,该组合遗迹化石种类较单一,主要为觅食迹,分布于潮间带和潮上带;3、Thalassinoides-Helminthopsis组合,该组合出现在潮间带。基于遗迹化石组合的分布特点,提出山西兴县奥陶系马家沟组五5亚段的沉积环境模式。     

塔里木盆地晚泥盆世东河塘组河口湾相遗迹化石

河口湾具有特定的环境条件和沉积组成,其遗迹化石具有半咸水沉积的遗迹群落特征。描述和分析塔里木盆地塔中4井区上泥盆统东河塘组河口湾沉积中的遗迹化石和生物扰动构造后,发现3类遗迹组构,其中Ophiomorpha遗迹组构发育在纯净砂岩中,与河口湾潮汐砂坝有关;Skolithos遗迹组构发育在薄层砂岩中,与河口湾砂坪有关;Palaeophycus遗迹组构发育在泥岩中,与河口湾泥坪、砂泥坪有关。     

遗迹化石的启示

生物遗迹化石,是古代生物生活时留下的痕迹和遗物。虫迹、脚印、爬痕、管穴,都属于此。它是自然界历史的绝妙的写照和见证。笔者采自甘肃省河西走廊五华山的一块灰黄色泥钙质粉砂岩标本上,比较明晰地展布着大小不等的孔眼,穿插不齐的管道,不甚规则的团块状堆积物,以及曲线形洼沟,洼沟内局部有依稀可辨的细横纹。它们分别显示了当年生活在软砂泥上的软体动物所遗留下来的钻孔、管穴、排泄物和爬痕的遗迹。这些遗迹,随着时间的运移,同软砂泥一道在成岩过程中石化了。今天这块标本上所见到的,仅仅是形形色色遗迹化石的沧海一粟——绮丽多彩、鬼斧神工的大自然产物的点滴记实。通常情况下,钻孔、管穴都开口在层面之上,从层面向下延伸,多不穿越底面;排泄物、爬痕等也只产于层面上。这是因为某些动物尽管营     

新疆雪豹调查中的痕迹分析

雪豹(Unciauncia)属于中亚高山高度濒危动物,夜行性,极其罕见。新疆雪豹研究小组2004年9~11月,在新疆的北塔山、阿尔泰山东部、天山东部和托木尔峰地区大约9个地点,对雪豹的痕迹进行了全面调查。共计完成67个样线,总长度47776m,其中发现遗留痕迹的样线有27条,痕迹数118个,平均为2.47个/km。记录到的痕迹有粪团、嗅痕(气味标记)、足迹、刨痕、卧迹、爪印、毛发、尿迹、血迹、剩余食物(动物尸体)和吼声等。同步还完成了200余份问卷调查表,充分了解雪豹与当地居民的冲突。最后,通过痕迹学的分析,初步掌握雪豹的栖息地选择、领域范围、分布规律和相对密度。这对于种群数量估计和物种的保护管理具有重要意义。     

Habitat change in braided flood plains (Tagliamento, NE-Italy)

1. Relative changes and age distribution of habitats were investigated in the active channel of a bar‐braided and an island‐braided reach of the Tagliamento River (NE‐Italy). Between September 1999 and January 2002, six habitat types were delineated with a differential Global Positioning System on five dates following floods of different magnitude. Overlay maps were employed to calculate age and relative change of habitats. We established exponential decay rates (k‐values) for islands and major aquatic habitats. 2. Relative changes of all aquatic habitats combined were up to 82% between survey dates in the bar‐braided flood plain, with a cumulative rate of 85% over the 2.5‐year period. Relative habitat changes in the island‐braided flood plain were lower with a cumulative change of almost 60% during the study period. In the bar‐braided flood plain significant exponential decay relationships were established for channels, alluvial channels, backwaters, and ponds. 3. Half‐lives were particularly short for backwaters and ponds. In the island‐braided reach, significant relationships existed for channels and alluvial channels. The half‐lives of channels and alluvial channels increased with the presence of vegetated islands. Relative habitat composition within the active corridor remained almost constant, supporting the applicability of the shifting mosaic steady state model to braided floodplain ecosystems. 4. Our results indicate that under natural conditions aquatic floodplain habitats can be highly dynamic over short time‐scales. Even small water level fluctuations (‘flow pulses’) can lead to major habitat changes with important consequences for the fauna and flora.     

川西南峨眉山地区上白垩统夹关组遗迹组构特征及其环境意义

川西南峨眉山地区上白垩统夹关组由一套厚层到块状中、细砂岩组成,夹有少量粉砂岩和泥岩,底部有砾岩。本组地层中发育有丰富的遗迹化石,共识别出9属11种。根据遗迹化石的分布情况,划分出了5种遗迹组构,即:Palaeophycus遗迹组构、Arenicolites遗迹组构、Skolithos遗迹组构、Planolites遗迹组构和Scoyenia遗迹组构;结合它们所分布岩层的沉积特征,认为前三者分别分布于河流环境中水动力强的边滩下部、水动力中等到较强的边滩中上部和边滩向堤岸过渡的环境,后两者分布于水动力较弱的天然堤环境。     

THE FISH AND AMPHIBIAN SWIMMING TRACES UNDICHNA AND LUNICHNIUM, WITH EXAMPLES FROM THE LOWER PERMIAN OF NEW MEXICO, USA

Abstract: The ichnotaxonomy and stratigraphic, geographic and environmental distribution of fish (Undichna) and amphibian (Lunichnium) swimming traces are reviewed. The ichnospecies of Undichna consist of various combinations of sinusoidal waves of differing complexity. Some of the more complex ichnospecies are made up of elements of the simpler forms, and morphological subset relationships between them are presented. Such subset series represent potential taphoseries relationships (i.e. preservational variants that reflect, for example, undertrails), or series of minor behavioural variations. Such a system can be used to highlight that different ichnospecies occurring at a locality may be taphonomic or minor behavioural variants of each other. Caution should, therefore, be exercised before erecting new ichnospecies on the basis of limited material if its morphology is a subset of an existing ichnospecies. However, the naming of such simpler ichnospecies is valid if they represent a recurrent morphology, and it is valid to erect new ichnospecies whose morphology is not a subset of an existing ichnospecies. Specimens that demonstrate intergradation between ichnotaxa can be used to justify their synonomy. Ichnotaxonomic revisions reduce the number of ichnospecies in Undichna from 14 to nine. U. radnicensis, a highly variable ichnospecies, is synonymized with U. britannica on the basis of material from China that demonstrates they can intergrade. U. prava is a partial U. tricosta, which falls within the minimum diagnosis of U. simplicitas. U. gosiutensis is regarded as a subjective junior synonym of U. quina. U. westerbergensis, originally attributed to a ‘crossopterygian’ fish performing a tetrapod‐like gait, is reassigned as a distinct ichnospecies within Lunichnium because it demonstrates the same morphology, representing similar behaviour, albeit by a different producer. L. anceps and L. gracile are synonymized with L. rotterodium. New specimens of U. bina and L. rotterodium are also described from the Lower Permian Robledo Mountains Formation of southern New Mexico, USA.     

The impact of flooding regime on the soil seed bank of flood‐meadows

Abstract. We assessed the significance of flooding for the floristic composition of seed banks in flood‐meadows of the northern valley of the Upper Rhine. We compared three hydrological compartments of the alluvial plain, consisting of the regularly flooded land between the river and low summer dykes (functional flood‐plain), the occasionally flooded land between summer dykes and high winter dykes (hybrid floodplain) and the land behind the winter dykes, which is now only submerged by ascending groundwater (fossil flood‐plain). Due to their different flooding regime, the three compartments should differ with respect to the prevailing conditions of diaspore input. The seed density of soil samples increased with the duration of flooding in the three compartments, while species richness and the proportion of species not occurring in the vegetation was constant. The increase in seed density can be largely attributed to an increase of disturbance indicators, which are present in the above‐ground vegetation and capable of forming a long‐term persistent seed bank. No effects of flooding on the composition of seed banks in the three flood‐plain compartments were found. The differences in seed bank composition can be largely explained by corresponding differences in above‐ground vegetation and former and present‐day meadow management. Seeds of species absent from above‐ground vegetation can be attributed to the local species pool present in the immediate vicinity of the study plots. We discuss consequences of the results for the restoration of species‐rich flood‐plain meadows.     

安徽巢湖孤峰组的放射虫化石*

安徽巢湖下二叠统孤峰组含有极其丰富的放射虫化石,这些化石主要由阿尔拜虫类(albaillellids),球形多囊虫类(spherical polycystine)和十字多囊虫类(stauraxon polycystime)所组成,其中以oalbail-lella scalprata,P.longtanensis,P.sp.cf.P.longicornis,Phaenicosphaera mammilla,P.sp.A,Ruzhence-vispongus uralicus,R.sp.A和R.sp.B占绝对优势.对这3类化石进行了较为系统的描述,建立两个新种Latentifistula triradiata,Quadriremis flata,和两个组合带,即Pseudoalbaillella scalprata-P.sp.cf.P.longicornis和Phaenicosphaera mammilla-Ruzhencevispongus uralicus组合带,并且将这两个带与国内外相应时代的组合带进行了比较,讨论了这两个带的时代.     

Meadow vegetation of the Desna flood plain, (Ucraine,USSR)

The meadow vegetation of the Desna river flood plain described by the authors is of great scientific significance as far as the protection of diversified syntaxa of inundation meadows is concerned. These syntaxa are different in their floristic composition. The largest inundation meadows of the Ukraine are best preserved in the flood plain of the Desna river where the authors have identified and described 18 associations of meadow vegetation attributed to 6 alliances, 2 orders and 2 classes of vegetation. They represent an ecological series ranging from steppe meadow to boggy meadows. The units thus specified are characterized by phytocenologic tables; the specificity and biological productivity of each association concerned being registered. The peculiar character of inundation meadows requires further more profound ecological and phytocenological studies of meadow communities which the authors propose for the future.     

云南景谷盆地晚第三纪介形类

该文首次报道景谷盆地介形类化石13属30种(其中19新种,1未定种)并建立3个介形类化石组合,三号构组以Potamocypris-Candoniella为代表的介形类化石组合,时代为中新世早期;回环组以Herpetocyprella-Metacypris为代表的组合,时代为中新世中晚期;大红猫村组以Leucocythere-Ily-ocypris组合为代表,时代为上新世。     

Variability of the sediment phosphate composition of a temporary pond (Doñana National Park,SW Spain)

This study reports on the spatial and temporal variability of the phosphate composition in the sediment of a temporary pond over a period of 3 years using the EDTA-method for P-fractionation. Sediment samples were collected at three different sites (open-water, littoral and flood plain) to compare the effect of the length of the wet/dry phase on the sediment phosphate composition, with special emphasis on the potential bioavailability of the P-fractions.Fine sediments (<0.1 mm) were rich in organic matter (9–25%) and contained high mean concentrations of Tot-P (182–655 mg kg^–1 d.w.), especially in the flood plain sediment. The sediment P composition was dominated by P-organic fractions at all sites (64–94%). The average C/N ratios were 8.8, 6.0 and 5.9 for sediments of the flood plain, littoral and open-water sites, respectively. The flood plain sediment was significantly poorer in iron-bound P (FeOOHP), but richer in the P-organic fractions extracted by EDTA than the sediment of the open-water site (P<0.01). The percentage of organic matter increased significantly in the sediment of the open-water site at the end of each dry season (P<0.05), while it decreased in the sediment of the flood plain site (P<0.01). In all sediments, the fraction of Fe(OOH)P decreased at the end of each dry season and some of these changes were significant (P<0.05). The decrease in the fraction of Fe(OOH)P was not related to changes in the sediment redox potential. Although the flood plain site was dry longer than the open-water site during the study period, the differences between the sediment composition of both sites were probably due to the effect of plant growth on the dry sediments of the flood plain site rather than to a direct effect of desiccation.