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1.
柴达木盆地冷湖构造的一些岩屑古生物分析发现,下干柴沟组上段存在一明显的化石轮藻Lamprothamnium ganchaigouensis组合带,而且这一组合带底界与下干柴沟组上段与下段的地质分界相当。在地震时间剖面上,通过井间追层及化石对比,发现这一化石组合带底界均与T4地震标准层相对应,形成了一个地震层序界面(等时界面)。因此,通过生物地层学与地震地层学的综合研究,可建立层序生物地层单元,具有层序生物地层学意义;地震与古生物资料的联合横向对比还可以帮助评估化石层位和标定地震标准层的相对位置,在生产实践中可节约成本,提高地层对比效率。  相似文献   

2.
Minwer‐Barakat, R., García‐Alix, A., Suárez, E.M., Freudenthal, M. & Viseras, C. 2012 xx xx: Micromammal biostratigraphy of the Upper Miocene to lowest Pleistocene continental deposits of the Guadix basin, southern Spain. Lethaia, Vol. 45, pp. 594–614. Recent study of the small mammals (rodents and insectivores) from several fossil‐bearing sites situated in the central sector of the Guadix Basin (Southern Spain) has notably increased the knowledge of the mammal assemblages that existed in Southern Iberia from the latest Miocene to the earliest Pleistocene. On the basis of this new information, we propose a biozonation for the continental deposits of the Guadix Basin, which consists of six biozones ranging in age from the late Turolian (MN13) to the early Villanyian (MN17). These biozones, defined according to the rules of the International Stratigraphical Guide, include not only the mentioned recently discovered fossil sites, but also other, previously known, localities of the basin. Finally, we integrate the described biozones in the Neogene Mammal units and the European Land Mammal Ages, correlate them with several classical mammal sites from other Iberian basins and the rest of Europe, and establish an approximate numerical age for the lower and upper limits of each biozone. □Biostratigraphy, Guadix Basin, rodents, insectivores, Upper Miocene, Pliocene, Pleistocene.  相似文献   

3.
Lithological and micropaleontological studies of core-samples from five boreholes drilled in the northeastern part of the coastal basin of Togo allow for a specification of the stratigraphy and the paleogeography of this area during the Maastrichtian and Paleogene. A lithological analysis reveals a marine series consisting of a Lower Maastrichtian unit, a Middle Paleocene to Eocene unit, and an upper unit attributed to the Continental terminal sensu lato. The biostratigraphical study, based on planktonic foraminifera, has led to a characterization of the basin in terms of biozones ranging from the Globotruncana aegyptiaca to the Abathomphalus mayaroensis biozones and biozones P5 to P11, thus specifying a Middle to Upper Maastrichtian, an Upper Paleocene and a Lower to Middle Eocene units. The paleogeographical evolution of the area shows that the series recorded two sedimentary cycles: the first one stops at the end of the Cretaceous and the second one in the Paleogene.  相似文献   

4.
蔚县盆地地处泥河湾盆地(广义)东南部,其河湖相地层内保留丰富的早期人类活动信息,在研究中国北方更新世人类演化和生存行为领域具有重要意义。吉家庄遗址是近年来新发现和发掘的旧石器遗址,埋藏于吉家庄镇以北的河湖相地层内。遗址发现于2003年,中国科学院古脊椎动物与古人类研究所于2016年对其四个地点(JJZ-A、JJZ-B、JJZ-C和JJZ-D)进行考古发掘,揭露面积76m~2,出土190件石质标本和178件动物化石。遗址剖面堆积物以棕灰-棕黄-灰绿-灰黑色细砂、粉砂和黏土为主,文化遗物出自棕灰色-棕黄色细砂和粉砂层内。对代表性地点JJZ-B遗址成因(标本风化磨蚀状况、个体大小和空间聚集特征等)分析表明,遗址形成过程中仅受到湖泊片流改造且程度较弱。石制品原料均来自遗址东北约6km外的玉皇山,岩性以中基性火山岩为主。锤击法剥片和修理石器,剥片和修理相对较为彻底和精致,部分石片显示小台面且保留唇的特点,显示早期人类的石器技术相对泥河湾盆地早更新世模式1(Oldowan-like)工业较为进步。哺乳动物化石较破碎,地层对比显示古人类在该遗址活动的时间大致为中更新世。该遗址的发掘对研究古人类在蔚县盆地的生活方式以及探求泥河湾盆地古人类在早-中更新世石器技术演变及适应策略具有重要意义。  相似文献   

5.
我国华北地区旧石器晚期遗址及文化遗物通常埋藏于河流的第二级阶地中,地质时代为晚更新世中、晚期。峙峪等遗址的地层清晰、化石丰富、时代明确,没有再搬运的任何迹象。研究旧石器文化必须结合地层、地貌和古生物资料进行综合分析,有适当的年龄数据印证,才能得出断代上的合乎逻辑的结论。  相似文献   

6.
The Holocene sedimentary record of core ZX-1, recovered west of mid-Holocene Chenier ridges on the monsoon-controlled Southern Yangtze delta, eastern China, consists of lagoon, salt marsh, upper tidal flat, and limnic facies, reflecting low-energy depositional environments. Holocene deposits mainly originated from the surrounding Tai Lake drainage basin. The temporal variation of most geochemical element percentages corresponds with the climatic phases inferred from the pollen record, i.e., the relatively low values of SiO2, Na2O, CaO and high values of Al2O3, K2O, MgO, Fe2O3, FeO, FeO + Fe2O3 and TiO2 generally concur with the warm and humid climate, and vice versa. Three geochemical indices − Al2O3/Na2O, K2O/Na2O, and CaO/K2O − are found to be sensitive to past precipitation in the monsoon-controlled southern Yangtze River delta. Based on fine sediment analysis of core ZX-1, the samples deposited under a dry climate with a mean annual precipitation (MAP) < 500–900 mm tend to have Al2O3/Na2O values less than 12.2, and the samples deposited under a moist climate with an MAP 1000–1800 mm mostly have Al2O3/Na2O values higher than 12.2. Similarly, the K2O/Na2O boundary value is 2.0. However, for CaO/K2O, the dry climate sediments likely show values higher than 0.9, and those wet climate ones generally have values less than 0.9. This geochemical response suggests the potential application of these indices in the interpretation of palaeoclimate variation of monsoon-controlled eastern China.

Holocene climatic variation history is reconstructed for the southern Yangtze delta. From 8000 to 7000 yr BP, regional climate demonstrated frequent fluctuations, with warm and wet periods (8000–7700; 7500–7200 yr BP) alternating with cool and less humid periods (7700–7500; 7200–7000 yr BP). From 7000 to 6000 yr BP, the climate was relatively warm and humid. Since then, it had turned cool and dry, climaxing in an intense cold event around 4000 yr BP. After the cold event, it became warm and humid until around 2500 yr BP.  相似文献   


7.
The origins of the modern British mammal fauna as a recognizable assemblage are traceable through preceding temperate woodland phases at least as far back as the early part of the Middle Pleistocene. Earlier Quaternary mammal assemblages have more in common with those of the Pliocene than those of the Middle Pleistocene, but evidence for gaps in the British Early Pleistocene sequence precludes inferences concerning the nature of this change in faunal composition.
A major difficulty in reconstructing Quaternary faunal histories is in establishing stable correlations between the fragmentary terrestrial sequences from which the fossil record has been recovered and in assembling those sequences into chronological order. Existing reconstructions of Quaternary events in Britain are of hybrid origin, a mix of palynological biostratigraphy based on assumed monocyclic floral successions for a small number of major interglacial stages, with intervening cold stages identified by characteristic glacial or periglacial lithologies and structures. While this framework has served as a useful basis for some Quaternary disciplines, some interpretations of the mammalian evidence do not fit it well.
Attention is given here to information derived from fossil mammal assemblages which may be used to help determine the number and sequence of Middle and Late Pleistocene temperate woodland phases with faunas showing close links with that of the Flandrian. While much of this information is not new, it has been largely ignored in the construction of some of the more widely known schemes for Quaternary subdivision. At present five such episodes can be identified and characterized prior to the present interglacial, though further refinement may br possible as work on a more detailed account of key sites arid their palaeontology progresses.  相似文献   

8.
The depositional conditions that characterized the sedimentary filling in the southern sector of the Guadalquivir Basin during the late post-orogenic Neogene have been established through the sedimentological study of the Plio-Pleistocene outcrops along the Cadiz coast (SW Spain). The study has contributed to a better interpretation of the regional stratigraphy and helped to establish both depositional mechanisms and processes. Deposits show different lithofacies according to the dominant climatic and prevailing environmental conditions. Pliocene deposits show bioclastic lithofacies with abundant warm-water fossils, whereas Pleistocene sediments have a low fossil content. Stratigraphic sections indicate important depositional changes: sandstone and grainstone were deposited under a seasonal regime, whereas accumulations of large boulders and bioclasts are interpreted as event deposits, the product of episodic oceanographic processes, such as huge storms or tsunamis. These deposits do not have a seasonal character; however, given their relative frequency in the stratigraphic sections, they were probably associated with neo-tectonic activity in the Guadalquivir Foreland Basin, which was an important controlling factor in this basin. The proximity to the Africa-Eurasia plate boundary together with several historically documented earthquakes and tsunamis in the study area, suggest that these processes could explain the origin of these deposits. The seismic-tectonic activity was more intense between the late Pliocene and early Pleistocene, as shown by the presence of a well-marked angular unconformity, as well as by a higher frequency of the very high energy clastic and bioclastic accumulations.  相似文献   

9.
贵州黔西观音洞钟乳石样的铀系年龄   总被引:5,自引:3,他引:2  
  相似文献   

10.
王頠 《人类学学报》2014,33(3):270-284
本文是2000年以来广西布兵盆地第四纪石器遗址的调查报告。布兵盆地是一个小型的断陷溶蚀盆地,发育南方典型的卡斯特地貌,洞穴众多并保存大量堆积物。盆地内发育2条小河,自西南向东北穿过盆地汇入右江,阶地广泛分布在盆地内部,可以确认的有4级阶地。旧石器在布兵盆地的第二至第四级河流阶地堆积物中均有发现,时代涵盖中更新世到晚更新世的多个阶段,一级阶地的后缘有新石器时代的遗物。布兵盆地的石器属于中国南方的砾石工业,石器文化包含旧石器时代早期的两面打制技术和旧石器时代晚期的以石片为主的加工技术。这些遗址的进一步综合研究,将对了解华南早期人类石器文化的起源和演化提供重要的科学依据。  相似文献   

11.
东海陆缘(浙南段)晚第四纪硅藻的发现及古环境分析   总被引:3,自引:0,他引:3  
东海陆缘(浙南段)温州沿海以往第四纪沉积已开展了一些研究,见有丰富的有孔虫、孢粉等生物化石,但未发现硅藻。本项研究在温州CH6井、台州CH5井岩心中发现了大量硅藻化石,本文以温州CH6井丰富的硅藻化石为依据,建立了晚第四纪硅藻组合序列,划分为12个硅藻带,并恢复其古环境演替,根据四个AMS ^14C年代数据,其时代属早、中全新世。  相似文献   

12.
宁波沿海平原第四纪沉积物属于海陆交互沉积,记录了良好的古气候变化信息,是研究古气候冷暖变化、沉积物沉积特征的良好载体.对位于宁波沿海平原东南部的Z02孔进行14C和古地磁测年,根据钻孔岩性、孢粉组合、有孔类和介形类组合、粒度等环境替代指标特征,确定了 Z02孔第四纪地层划分,揭示了研究区第四纪以来的古环境演变信息.结果...  相似文献   

13.
蔚县盆地地处泥河湾盆地(广义)的东南端,是更新世人类活动的重要区域。2017-2018年,中国科学院古脊椎动物与古人类研究所等在盆地内开展系统的旧石器考古调查,新发现并确认了27处旧石器地点。相关地貌、地层对比显示,新地点年代可大致分为中更新世和晚更新世晚期两个阶段,文化遗物分别埋藏于泥河湾河湖相堆积和黄土堆积中。中更新世石制品类型包括石核、石片、石器和断块等,原料以火山岩为主,均采用锤击法进行剥片和修理石器;晚更新世晚期遗址包括石核、石片和细石叶等,原料以白云岩和燧石居多,火山岩次之,以硬锤锤击法为主要剥片技术,软锤技术少量发现。对石制品初步分析表明,蔚县盆地中更新世地点表现出了一套与阳原盆地早-中更新世不同的原料及石制品组合,且在蔚县盆地晚更新世晚期存在小型石片石器和细石器两种工业。本次调查扩大了泥河湾盆地古人类活动的地理范围与文化内涵,为揭示泥河湾盆地(广义)早期人类的迁徙与适应行为提供了有价值的线索。  相似文献   

14.
PLEISTOCENE HISTORY OF THE BRITISH VERTEBRATE FAUNA   总被引:1,自引:0,他引:1  
  • 1 This review covers the Pleistocene history of British non-marine Pisces, Amphibia, Reptilia and especially Mammalia, which alone have a good fossil record. Aves are also briefly discussed.
  • 2 The fossil material available is often inadequate for purposes of taxonomy and identification. Further problems arise because many groups of Mammalia have undergone rapid evolution during the Pleistocene.
  • 3 In this paper the fossil record is related to the currently accepted stratigraphic table of the British Pleistocene (Shotton & West, 1969). Wherever possible, fossil records have been assigned to pollen assemblage zones. Throughout, emphasis is placed on the relationship between faunal history and vegetational history, as determined from fossil pollen and macroscopic plant remains.
  • 4 Although fossils are relatively scarce in the fluviatile and lacustrine deposits of open sites, compared with the often rich cave assemblages, the stratigraphy of the former is usually much clearer and the sediments commonly contain pollen. It is difficult to correlate cave sequences with those of open sites.
  • 5 It is important to take into account possible bias in a fossil assemblage according to its mode of accumulation, e.g. assemblages from occupation sites may represent only those animals which were hunted by man.
  • 6 Lower Pleistocene vertebrates are rather poorly-known. The majority of fossils are from the marine Crags of East Anglia (Pre-Ludhamian to Pastonian) and a single cave assemblage of this age is known (Dove Holes). Few records can be related to particular stages, but a few finds from Easton Bavents are assigned to Antian and Baventian stages.
  • 7 Early Middle Pleistocene vertebrates are represented mainly by the rich assemblages from the marine and fresh-water Weybourne Crag and Cromer Forest Bed Series (Baventian to Early Anglian) of Norfolk and Suffolk. The East Runton fauna appears to be of pre-Cromerian (?Pastonian) age. A good fauna is known from the type Cromerian deposits at West Runton (zone Cr 11). A few records are available for zone ?Cr III and one for the Early Anglian. The assemblages from other localities appear to represent more than one stage at each site, e.g. the so-called ‘Bacton Forest Bed’ fauna is composite, including both Cromerian and ?Pastonian taxa. Outside East Anglia one open site (Sugworth) and one cave fauna (Westbury) of probable Cromerian age are known.
  • 8 Many of the fossils found in lacustrine and river-terrace deposits of the Middle and Upper Pleistocene glacial-interglacial succession (Anglian to present day) can be assigned to particular stages, zones or even subzones. Cave assemblages rarely predate the Ipswichian. No pre-Devensian records are available for either Scotland or Ireland. The Anglian fauna is very poorly known. The Hoxnian is represented principally by the Clacton (zone Ho IIb) and Swanscombe faunas. The Baker's Hole deposit, the basal gravels of the Summertown-Radley Terrace and the Glutton and Bear Strata in Tornewton Cave have yielded faunas of probable Wolstonian age. The early Ipswichian is poorly represented (Selsey), many fossils are known from zone Ip Iib (e.g. Trafalgar square, Swanton Morley, Aveley), there are a few records from early zone Ip III (Aveley, Swanton Morley) and fairly good faunas from zone Ip III/IV (Histon Road, Stutton). Several open and cave-site faunas resemble those of zones Ip II and Ip III and the assemblages from Ilford, Brundon, etc., appear to date from the end of this interglacial. The Early Devensian is represented by the Wretton fauna and probably by some cave faunas. Middle Devensian faunas are fairly well known (e.g. Upton Warren) and there are a number of records for the Late-Devensian (Ballybetagh, High Furlong, Nazeing). Many cave faunas date from the Middle or Late Devensian. Good faunas are available from the early Flandrian, zone F1 I (e.g. Star Carr). The present-day native fauna (zone F1 111) is also discussed.
  • 9 The main faunal characteristics for each subdivision of the Pleistocene are summarized in the Conclusions. There is a major faunal change between the predominantly Tertiary fauna of the Red Crag Nodule Bed (Probably Pre-Ludhamian and older) and that of the Red Crag (Pre-Ludhamian and Ludhamian). There appears to have been comparatively little change in fauna through the rest of the Lower Pleistocene but the more intense climatic fluctuations of the Middle and Upper Pleistocene were accompanied by rapid faunal change and the appearance of characteristic ‘steppe-tundra’ faunas in the Wolstonian and Devensian cold stages. The Late-Devensian and Flandrian faunas are impoverished in comparison to earlier stages. This may be partly due to the activities of man as well as climatic and vegetational changes.
  • 10 There is usually good agreement between fauna and vegetational conditions when these can be compared, but a few taxa (e.g. Cricetus cricetus, Equus) have clearly changed their ecological requirements during the Pleistocene. Changes of fauna in response to vegetational changes within interglacials are known from the Hoxnian and especially the Ipswichian. The ‘steppe-tundra’ vegetation of cold stages was accompanied by a mixture of animals nowadays extinct or living in either steppe or tundra.
  相似文献   

15.
以苹果M9T337幼苗为试材进行水培试验,采用15N和13C同位素示踪技术,研究不同供钾水平(0、3、6、9、12 mmol·L-1,分别以K0、K1、K2、K3、K4表示)对M9T337幼苗生长、光合特性与15N、13C吸收利用的影响.结果表明: K2处理M9T337幼苗各器官干质量、根系长度、根系表面积、根尖数和根系活力均显著高于其他处理.叶片净光合速率(Pn)随着供钾水平的升高先上升后下降,在K2处理时达到最高值,为15.5 μmol CO2·m-2·s-1.处理30 d后,硝酸还原酶(NR)和碳代谢酶活性均以K2处理最高,K0处理最低.随着供钾水平的提高,各处理幼苗的13C积累量呈先升高后降低的趋势,且在K2处理时各器官13C分配率最均衡.各处理间15N吸收量和利用率差异显著,K2处理下幼苗的15N吸收量和利用率最高,分别为16.11 mg和17.9%,是K0处理的3.0倍.因此,钾素供应过低或过高均抑制幼苗根系生长和叶片光合作用,不利于植株碳氮吸收,而适宜的钾素供应水平可以提高根系活力和净光合速率,增强硝酸还原酶(NR)和碳代谢酶活性,从而促进碳氮代谢.  相似文献   

16.
本文根据武家村发现的第四纪哺乳类,海、陆相软体类化石,以及地层中所含的植物孢粉和岩性特征,把该地区第四纪地层初步划分为全新统、晚更新统、中更新统(陆相沉积)和早更新统(海相沉积)。  相似文献   

17.
三门峡地区含哺乳动物化石的几个第四纪剖面   总被引:2,自引:0,他引:2  
黄河三门峡地区的晚新生代哺乳动物化石包括了上新世至晚更新世各个层位,其中以早更新世的材料较多,有七种与泥河湾动物群是相同种;有4种与山西榆社、临猗和西侯度等地点的早更新世动物群是相同种。这说明三门峡地区早更新世动物群相当于维拉方晚期或中晚期。三门系属河湖沉积,但比黄河发育的历史为早,而黄河的沉积系贾福海等划分的第5层。为此,黄河形成的时间恐怕是早更新世之末或中更新世之初。  相似文献   

18.
Spanish and Swedish populations of Helophorus lapponicus are shown on fossil evidence to have been isolated from one another for about 10 000 years, since the end of the Pleistocene. When cross-bred they show some evidence of heterosis in the F1, with reduced viability in the F2 and back-cross generations. The level of compatibility of these populations is similar to that found when different populations of Lepidoptera species are crossed, and quite different from the incompatibility revealed by studies of interspecific hybridization. The degree of evolutionary stability revealed is consistent with the apparent absence of evolution revealed by studies of Pleistocene fossil Coleoptera.  相似文献   

19.
Photosystem I preparations were irradiated with UV to destroy vitamin K1 in situ. The depletion of vitamin K1 resulted in inactivation of NADP+ photoreduction and introduction of a 220 ms component in the flash generated P700+ re-reduction at room temperature. The photoreduction of the terminal FeS centers FA and FB in control and vitamin K1-depleted preparations at 7 K were comparable. The data confirm that vitamin K1 is functionally implicated in primary electron transfer reactions in PS I at physiological temperature, and that the anomalous results at cryogenic temperature may be explicable in terms of a by-pass of the vitamin K1 acceptor site or heterogeneity introduced into the photosystem by quinone removal.  相似文献   

20.
研究平邑甜茶幼苗NO3--N吸收和利用特性对不同供钾水平的响应,旨在明确钾肥对氮肥吸收利用的影响,从而为果园科学施肥提供理论依据.以平邑甜茶幼苗为材料进行砂培试验,设置K0、K1、K2、K3、K4、K5、K6 7个钾浓度处理,分别相当于0、2、4、6、8、10、12 mmol·L-1 K+,运用15N同位素示踪技术和非损伤扫描离子选择电极技术,测定了不同供钾水平下平邑甜茶的氮素吸收和利用情况.结果表明: K3处理平邑甜茶幼苗根系活力、硝酸还原酶活性以及根系形态指标均显著高于其他处理.与其他处理相比,K3处理根、茎、叶从肥料中吸收分配到的15N 量对该器官全氮量的贡献率(Ndff)均达到最高,分别为K0处理的1.36、1.33和1.47倍.随供钾水平的增加,植株氮素利用率呈现先增高后降低的趋势,且在K3处理时最大,为23.3%,是K0处理的3.04倍.非损伤微测技术结果显示,K3处理时,平邑甜茶根系对NO3-有强烈吸收且内流速度达到最大,为19.34 pmol·cm-2·s-1;在缺钾(K0)和高钾(K6)处理时有明显外排趋势.因此,钾的亏缺或过量均抑制氮素的吸收和利用,适当供钾能够促进幼苗根系生长,增强硝酸还原酶活性,从而促进平邑甜茶对氮素的吸收.  相似文献   

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