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1.
许家窑-侯家窑遗址地层穷究   总被引:2,自引:0,他引:2  
卫奇  吴秀杰 《人类学学报》2012,31(2):151-163
许家窑-侯家窑遗址是中国旧石器时代中期一处重要的考古遗址, 出土的化石"许家窑人"属于早期智人。按照现行地层古生物学常规判断, 其地层应该属于上更新统。目前, 许家窑组是泥河湾盆地乃至东亚地区发现的上更新统包含古人类及其旧石器文化遗物和古哺乳动物化石相当丰富的一个地层剖面, 但断代存在理念误区。  相似文献   

2.
131 ammonites, whole or in fragments, were collectedbetween 1958 and 1977 within 150 m of the Jurassic section at Hamakhtesh Hagadol (Hathira), Negev. A detailed paleontological study allows the recognition of twenty four species ascribed to ten genera; one genus and four species being new. Their age assignment is Middle and Late Callovian. The specific character of this fauna and its relationships to other assemblages in neighbouring regions are discussed.  相似文献   

3.
The liassic beds of the High-Atlas of Marrakech are rarely fossiliferous so all paleontological discoveries must be reported in order to give more biostratigraphical precisions for the interpretations of the sourcestrata basin. Palynological investigations in section composed of marl and dolomites with gypsum yield assemblages which the overall composition is characterized by the general dominance of Corollina in combination with relatively rare occurence of others nonsaccate pollen grains. Because the comparison of the associations previously described from the Lower Jurassic of Morocco and Sahara and the fact that the richness of Corollina has no stratigraphical value, the assemblages from the Telouat' section can be reasonably regarded to be indicative of a Sinemurian age.  相似文献   

4.
Environmental conditions and productivity changes in the southeastern Okhotsk Sea have been reconstructed for the last 20 ka using planktonic and benthic foraminiferal oxygen isotope records and calcium carbonate, organic carbon and opal content data from two sediment cores. Species variability in benthic foraminiferal and diatom assemblages provides additional palaeoceanographic evidence. AMS radiocarbon dating of the sediments and oxygen isotope stratigraphy serve as the basis for the age models of the cores for the last 20 14C kyr and for correlation between environmental variations in the Okhotsk Sea, and regional and global climate changes. Benthic foraminiferal assemblages in the two cores (depth 1590 and 1175 m) varied with time, so that we could recognise seven zones with different species composition. Changes in the benthic foraminiferal assemblages parallel major environmental and productivity variations. During the last glaciation, fluxes of organic matter to the sea floor showed strong seasonal variations, indicated by the presence of abundant A. weddellensis and infaunal Uvigerina spp. Benthic foraminiferal assemblages changed with warming at 12.5–11 and 10–8 14C kyr BP, when productivity blooms and high organic fluxes were coeval with global meltwater pulses 1A and 1B. Younger Dryas cooling caused a decline in productivity (11–10 kyr BP) affecting the benthic faunal community. Subsequent warming triggered intensive diatom production, opal accumulation and a strong oxygen deficiency, causing significant changes in benthic fauna assemblages from 5.26–4.4 kyr BP to present time.  相似文献   

5.
The amount and quality of paleontological data is rapidly increasing thanks to the new developments in geological dating, 3D visualization and morphometrics, chemical and histological analysis, and database storage. However, despite the fact that data from fossils, their assemblages, temporal successions, spatial gradients and environments are of an evolutionary-ecological nature, their contribution to current mainstream evolutionary-ecological theory and methodology is low. The use of fossils is not seldom restricted to calibration (e.g., in phylogenetics), or source for historical speculation after having analyzed modern data first (e.g., in macroecology). Yet, the scale of resolution of many paleontological time series (103–105 years) is highly apt for studying the dynamics of species, the average lifetime of which is in the order of 106–107 years. In order to fully profit from the wealth of data from the rock archive, a large-scale “stratophenomics” approach is needed. The resulting data archives will not only further contribute to an increase in the knowledge of past species, communities and environments, but will also generate more and innovative theory on the mechanisms underlying species and higher taxon dynamics. Examples of new and promising approaches towards generating paleontological data will be presented under the headings of the three major stratophenomics dimensions: time, morphology and environment. Highlighted fields include astrochronology, sclerochronology and 3D morphometrics.  相似文献   

6.
Benthic foraminifera in surface sediments from northeastern Canada and the Beaufort Shelf were studied to determine the quantitative relationship between recent assemblage distributions and modern water depth, temperature and salinity. Factor analysis shows that 7 factor assemblages account for 92% of the variance between samples. Multiple linear regression shows that different factors are significantly related to water depth, August bottom water temperature or salinity. Multiple correlation coefficients for depth, temperature and salinity are 0.94, 0.72 and 0.92, respectively. Labrador fjords contain arenaceous faunas dominated by eitherSaccammina atlantica andReophax fusiformis or byEggerella advena. Regression analysis shows that theSaccammina-Reophax factor is most strongly related to salinity. TheEggerella factor is related to depth and temperature. A fauna dominated byTrochammina nana andBuliminella elegantissima is correlated with warm, deep water in Davis Strait. Calcareous assemblages dominated byElphidium excavatum orCassidulina reniforme are found in Arctic bays and shelf areas. These factor assemblages are strongly related to temperature and depth;Cassidulina is also related to salinity. AnIslandiella helenae fauna on the inner Labrador Shelf is strongly correlated with depth and salinity. ANonionellina labradorica fauna in deep shelf basins is closely related to salinity.The multiple regression model for the sea-bed data estimates water depth, August bottom water temperature and salinity within confidence limits of ± 67 m, 1.3°C and 1.0‰. Paleoecological transfer functions were used to quantify environmental changes recorded by the foraminifera in two piston cores on a transect across the Labrador Shelf. Paleo-depth estimates obtained from the core data produce relative sea-level curves which are similar in shape to theoretical curves for this region. Paleo-salinity and -temperature estimates for offshore Core 12 show that the change from a postglacialNonionellina fauna to a late glacialE. excavatum fauna is accompanied by a decrease of about 2‰ in salinity and 4°C in temperature. Paleoecological estimates for fjord Core 111 show that the change from a modernSaccammina-Reophax fauna to a mid-HoloceneI. helenae fauna corresponds to a salinity increase of 3–5‰ and temperature increase of 1–2°C.  相似文献   

7.
A poorly preserved, but diversified radiolarian fauna was recovered from thin-bedded cherts occurring in the southeast of Daofu, Sichuan Province, southwestern China. Twenty-two radiolarian species belonging to 10 genera are identified and three new species (Paroertlispongus daofuensis n. sp., Falcispongus heinzi n. sp., Falcispongus pauliani n. sp.) are described. Falcispongus heinzi represents a transitional species between genera Oertlispongus inaequispinosus Dumitrica, Kozur and Mostler and Falcispongus Dumitrica. The fauna is divided into two assemblages, namely Muelleritortis cochleata and Oertlispongus inaequispinosus assemblages, which can be well correlated with the Ladinian radiolarian zones from Europe. The fauna indicates that basaltic rocks occurring in the Xianshuihe Belt were formed mainly during the Middle Triassic. Our results thus extend the previously known geological age of the Xianshuihe Belt to the Middle and Late Triassic interval.  相似文献   

8.
Foraminifers from typical Kulm environments are described from 4 localities at the eastern and northern border of the Rhenish Massif: aQuasiendothyra fauna of uppermost Devonian age (Famennian); a Chernyshinellinae fauna of the lower Dinantian Cf1 Zone (middle Tournaisian); upper Dinantian foraminifers from the Cf4δ to Cf6γ Zones (Middle and Upper Viséan). The foraminifer assemblages of the Cf6 Zone (V3b + c), in theGoniatites crenistria schmidtianus toNeoglyphioceras spirale Subzones, seem to be variegated in Germany and Belgium, but they are definitively poorer than contemporaneous faunes in the British Isles and the Russian Platform.  相似文献   

9.
《Palaeoworld》2020,29(1):75-87
Typical early Viséan foraminiferal assemblages documented in outcrops of the Western Meseta of Morocco led to the erroneous biostratigraphic dating of areas that later, after much effort, have been demonstrated to correspond to the mid and late Viséan. These sections are analyzed to decipher if they are formed by reworked specimens or if this fauna really survived into younger rocks. Key sections are located in vast areas of the Western Meseta, in the north of the Azrou-Khenifra basin, Fourhal area, El Hammam Ridge, Oulmès area, Sidi Bettache basin (all on the north of the Western Meseta), and the Skoura region (on the southern border). The environmental settings as well as the taphonomical stage of preservation of the foraminifers suggest that most of the assemblages are composed of autochthonous or parautochthonous foraminifers and, thus, that the fauna really survived into the middle and even upper Viséan carbonate platforms of the Western Meseta. In some sections, the early Viséan foraminifers share the same levels with mid Viséan foraminifers; in others, they share the same levels with mid and late Viséan foraminifers, and in a third group, the early Viséan foraminifers occur in the same stratigraphic sections with mid and late Viséan assemblages, although never in exactly the same stratigraphic levels but alternating. These distributions exemplify the three patterns of interaction between the stratigraphic and biogeographic ranges of the assemblages.The absence of similar patterns is noteworthy in the surrounding regions of the Palaeotethys, and thus, this anomalous distribution can be discarded as a matter of dispersal from neighbouring regions. The absence of similar patterns in basins situated far from the Western Meseta allows abiotic factors to be discarded, such as tectonic/environmental setting, palaeolatitude or isolation. The most plausible hypothesis to explain the survival of these fauna is related to biotic factors, such as species interaction and competition, and they can be compared to some similar modern ecological patterns. However, the primary triggering factor allowing these biotic factors to interact is considered to be the late arrival of the mid Viséan foraminifers to the Western Meseta, allowing them to occupy niches completely different from the rest of the Palaeotethys.  相似文献   

10.
Abstract: Eleven randomly chosen outcrops in the Miocene Pakhna Formation of Cyprus were sampled for holoplanktonic Mollusca. Four species of Heteropoda were found, and 24 of Pteropoda, a substantial increase from the two species recorded until now from the Miocene of Cyprus. One pteropod species, Peracle charlotteae sp. nov. (Gastropoda, Pseudothecosomata), is introduced. Age assignments based on holoplanktonic molluscs for the 11 localities are as follows: Langhian (Alassa 1–4), (Serravallian?) Tortonian to Messinian (Episkopi 1), Tortonian (Agios Tychon, Tokhni and the Maroni Marlstone of Khirokitia 1–2) and Tortonian to Early Messinian (Episkopi 2). These age determinations in some cases are at odds with those from previous publications based on calcareous nannofossils and Foraminifera. The sediments underlying the Amathus Channel outcrop yielded insufficient fauna for definitive dating, but we suggest are younger than Late Serravallian. At some localities, particularly in the Alassa area, pteropod assemblages are strongly variable on a bed‐by‐bed basis, and this offers possibilities for future refined biostratigraphical interpretations. This is the first substantial holoplanktonic mollusc fauna described from the eastern Mediterranean basin and allows correlation with assemblages in the central Mediterranean and elsewhere.  相似文献   

11.
Bernard Crochet 《Geobios》1977,10(5):723-739
Limestone beds included in the «Poudingue dePalassou around Sabarat (Ariège) contain a Gasteropod fauna known since J.-B. Noulet's works (1857). The systematic inventory of the different localities and the paleontological study of the material collected prove that two successive and clearly different Mollusc faunas existed. The bartonian fauna with Ischurostoma formosum minutum (Noulet) and Biomphalaria vasseuri (Roman) is preceded by a lower lutetian fauna with Biomphalaria pseudoammonius (Scholtheim): in the latter, two paleoecological groups are opposed according to the sheltered channels of two kinds in which limestones beds have been built. Besides, the chronostratigraphic consequences imply that the middle part of the «Poudingue de Palassou has been formed from Lower Lutetian to Bartonian.  相似文献   

12.
There remains limited knowledge of how offshore windfarm developments influence fish assemblages, particularly at a local scale around the turbine structures. Considering the existing levels of anthropogenic pressures on coastal fish populations it is becoming increasingly important for developers and environmental regulators to gain a more comprehensive understanding of the factors influencing fish assemblages. Improving our ability to assess such fish populations in close proximity to structures will assist in increasing this knowledge. In the present study we provide the first trial use of Baited Remote Underwater Stereo-Video systems (stereo BRUVs) for the quantification of motile fauna in close proximity to offshore wind turbines. The study was conducted in the Irish Sea and finds the technique to be a viable means of assessing the motile fauna of such environments. The present study found a mixture of species including bottom dwellers, motile crustaceans and large predatory fish. The majority of taxa observed were found to be immature individuals with few adult individuals recorded. The most abundant species were the angular crab (Goneplax rhomboides) and the small-spotted catshark (Scyliorhinus canicula). Of note in this study was the generally low abundance and diversity of taxa recorded across all samples, we hypothesise that this reflects the generally poor state of the local fauna of the Irish Sea. The faunal assemblages sampled in close proximity to turbines were observed to alter with increasing distance from the structure, species more characteristic of hard bottom environments were in abundance at the turbines (e.g. Homarus gammarus, Cancer pagarus, Scyliorhinus spp.) and those further away more characteristic of soft bottoms (e.g. Norwegian Lobster). This study highlights the need for the environmental impacts of offshore renewables on motile fauna to be assessed using targeted and appropriate tools. Stereo BRUVs provide one of those tools, but like the majority of methods for sampling marine biota, they have limitations. We conclude our paper by providing a discussion of the benefits and limitations of using this BRUV technique for assessing fauna within areas close to offshore windfarms.  相似文献   

13.
The Middle Awash paleontological study area, located in the Afar Rift of Ethiopia, has yielded fossils spanning the last six million years. The geology and geochronology of the Mio-Pliocene sites of the study area have been refined and a reliable chronostratigraphy has been established by 40Ar/39Ar radiometric dating. The latest Miocene Adu-Asa Formation is divided into four members distinguished from each other by silicic and basaltic tuff marker horizons, most of which are dated basaltic tuffs. Radiometric dating has constrained the age of the Adu-Asa Formation to between 5.2-5.8 Ma. These dates are also supported by paleomagnetic results and biochronology. More than 2,000 fossil specimens were collected from the Adu-Asa Formation between 1992 and 2000. These fossils document 64 mammalian species belonging to 32 genera, 23 families, and 8 orders. This assemblage includes a number of new taxa. Included in the assemblage are First and Last Appearance Datums (FADs and LADs) of some groups, including the earliest record of the hominid genus Ardipithecus. Most of the taxa indicate a predominance of mesic and wooded habitat during the deposition of the Adu-Asa Formation. In these deposits, colobines, viverrids, mustelids, bovines, boselaphines, and tragelaphines are abundant, whereas alcelaphines are absent. Quantitative analyses of biogeographic relationships of the Middle Awash Late Miocene (MALM) mammalian fauna indicate stronger relationships with other African sites than with faunas from Eurasian sites. The MALM deposits have generated a critical dataset for analytic work on past environments, biogeographic relationships, and African vertebrate evolution. Moreover, the geographic position of the Middle Awash, coupled with its precise calibration and chronological span, make it a key section for interpreting latest Miocene faunal interchanges between Africa and Eurasia.  相似文献   

14.
Eleven species belonging to ten genera of fresh water Ostracoda, have been identified from thirteen sediment samples collected from the bottom of permanent streams running along the N-NE part of Socotra Island. The fauna shows close affinity with the S-E African and S-E Asian assemblages, with interesting findings regarding the Palearctic Limnocythere stationis Vávra, 1891. The taxonomy and geographic distribution of the fauna are here discussed in detail.  相似文献   

15.
The study of otolith assemblages from the pre-evaporitic Messinian deposits allows the reconstruction of a fauna of 79 taxa of which 35 could be identified at the specific level. Three of these are new: Diaphus rubus, Myctophum coppa, and Uranoscopus ciabatta. The assemblages reflect mainly a neritic environment influenced by the oceanic realm. Analysis of the global present-day geographic distribution of 42 of the recognised Messinian genera indicates that 88% of these are still living in the Mediterranean, 98% in the Atlantic and 78% in the Indo-Pacific realm. These results are in good agreement with the evolutionary trends documented for the Oligocene and Miocene teleost fauna, specifically an increase in percentage of genera inhabiting the modern Mediterranean, a very high percentage of Atlantic and Indo-Pacific genera, and a slight fall of the importance of present-day Indo-Pacific genera from the Rupelian up to the Late Miocene. Analysing the composition of the Early Messinian fauna at the level of nominal species indicates that about 53% of the species represented in the assemblages are still living in the Recent Mediterranean, and that a significant number of these were already present in the Tortonian. It is interesting that these species are mainly neritic. This seems to confirm that the close affinity of the fossil assemblage with the present-day Mediterranean neritic fauna, which was already recorded at the genus level for the Rupelian fauna, persists during the Neogene and continues until the Pleistocene.  相似文献   

16.
The species composition and diversity of Lepidoptera Rhopalocera were studied on the Solovetskie Islands during five years (2001–2005). Twenty-nine species of five families were recorded. The most abundant species are Leptidea sinapis, Boloria aquilonaris, Heodes virgaureae, Plebejus argus, Arcia eumedon, and Cyaniris semiargus. The fauna of these islands is poorer than local faunas of the continental northern taiga, forest-tundra, and southern tundra of Europe. The species diversity of insular assemblages of diurnal lepidopterans is lower in comparison with analogous continental assemblages. They are characterized by the mixed species composition, when species with different ecological preference occur within the same habitat.  相似文献   

17.
The shallow-water nematodes of the White Sea are relatively well studied; however, information on the nematode fauna inhabiting the deepest part of this sea is very scarce. The composition of the nematode assemblages (at species and genus level) was studied in samples collected during four sampling occasions in the deepest part of the Kandalaksha Depression (the White Sea) in July 1998, October 1998, May 1999, and November 1999. Samples were collected from a depth of 251–288 m with the aid of a multicorer. In total, 59 nematode morphotypes belonging to 37 genera and 18 families were distinguished. The genera Sabatieria and Filipjeva dominated at all stations, followed by Aponema, Desmoscolex, and Quadricoma. The composition of the dominant genera can be considered typical for this depth range in temperate and Arctic waters, although Filipjeva and Aponema were among the dominant genera for the first time. The most abundant species were Sabatieria ornata, Aponema bathyalis, and Filipjeva filipjevi. In general, diversity of the nematode assemblages was lower than in the temperate and Arctic continental shelf and slope with reduced evenness and species richness. The evenness of nematode assemblages and other diversity indices decreased with increasing sediment depth. Based on the valid species and genera recorded, the nematode fauna of the Kandalaksha Depression showed a higher resemblance to that found in the shallow waters of Kandalaksha Bay.  相似文献   

18.
In the last 20–30 years, the temperature of the Mediterranean Sea has increased and global warming is allowing the establishment of tropical-affinity species into more temperate zones. Sessile communities are particularly useful as a baseline for ecological monitoring; however, a lack of historical data series exists for sessile marine organisms without commercial interest. Hydroids are ubiquitous components of the benthic sessile fauna on rocky shores and have been used as bio-indicators of environmental conditions. In this study on the benthic hydroid assemblages of the Chafarinas Islands (Alboran Sea, South-Western Mediterranean), we characterized the hydroid assemblages, identified the bathymetric gradients, and compared them with a previous study carried out in 1991. Hydroid assemblages showed a significant difference both between year and among depths. Furthermore, eight species not present in 1991 were found, including two possible new species and the tropical and subtropical species Sertularia marginata. Due to its strategic position at the entrance of the Mediterranean and the existence of previous data on hydroid assemblages, the Chafarinas Islands are proposed as a possible monitoring point for entrance of Atlantic tropical species into the Mediterranean Sea.  相似文献   

19.
In this article, a summary of the geologic, paleontological, and human history of an area of the Atlantic coast in the Pampean plain, Argentina is discussed. This area presents very interesting characteristics. On the one hand, the area includes the Monte Hermoso cliffs studied by Charles Darwin in 1832, which compose the set of localities related to the development of the theory of evolution. On the other hand, in the referred area, an extraordinary amount of human and Pleistocene mammal footprints are registered. Also in that section, four diachronic stages have been registered which depict the evolutionary scenario during the last five million years. Four paleontological and archeological sites are described, showing the palaeoenvironmental changes that occurred there regarding fauna associations and human settlement. The first scenario is found at Monte Hermoso cliff, whose sediments contain fossil remains of the autochthonous South American fauna. The second scenario shows a remarkable change in the drainage system where the fauna is composed of immigrated taxa due to the Great American Biotic Interchange. Both last scenarios show human presence; the third one shows faint evidences (one human trackway and two isolated footprints), and in the last one the hunter–gatherers are fully represented as a well-established population on the Pampean coast during the Early Holocene, registered at La Olla and Monte Hermoso I sites. In this way, the sites summarized in this work allow the reconstruction of four remarkable evolutionary scenarios in South America, as regards landscapes, fauna associations, and human population.  相似文献   

20.
Borelis melo andDendritina sp. occur in Messinian carbonates of the Cabo de Gata near Almeria. This is the first record of these larger benthic foraminifera from Messinian deposits in SE Spain. Two foraminiferal assemblages are differentiated: firstly, aBorelis- Dendritina assemblage which occurs on reef flanks, and secondly a lagoonal monospecificDendritina fauna.  相似文献   

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