共查询到18条相似文献,搜索用时 156 毫秒
1.
通过对西藏羊湖地区ZK1和卡拉苏代牙剖面(IP16)的孢粉分析和总有机碳(TOC)、元素含量分析等,建立了羊湖地区近1.4万年以来的孢粉组合带、重建当时的植被类型及古气候演变序列.结果显示:该时期经历了5次植被类型的更替,即草原型→疏林草原型→草原型→疏林草原型→草原型,与之相对应的气候经历了5次波动(2个半旋回),即11220a.B.P.左右的第一气候旋回:由干旱→半干旱半湿润转化;8970a.B.P.左右的第二气候旋回,同样由干旱→半干旱半湿润转化,然后进入半个气候旋回,即干旱气候期,推测今后有可能进入半干旱半湿润气候期. 相似文献
2.
西藏羊湖地区及近1.4万年以来孢粉植物群及古气候研究 总被引:1,自引:0,他引:1
通过对西藏羊湖地区ZK1和卡拉苏代牙剖面(IP16)的孢粉分析和总有机碳(TOC)、元素含量分析等,建立了羊湖地区近1.4万年以来的孢粉组合带、重建当时的植被类型及古气候演变序列。结果显示:该时期经历了5次植被类型的更替,即草原型→疏林草原型→草原型→疏林草原型→草原型,与之相对应的气候经历了5次波动(2个半旋回),即11220a.B.P.左右的第一气候旋回:由干旱→半干旱半湿润转化;8970a.B.P.左右的第二气候旋回,同样由干旱→半干旱半湿润转化,然后进入半个气候旋回,即干旱气候期,推测今后有可能进入半干旱半湿润气候期。 相似文献
3.
4.
晚更新世以来呼伦湖地区孢粉植物群发展与环境变迁 总被引:10,自引:1,他引:9
呼伦湖是我国纬度最高的湖泊。晚更新世以来,由于气候冷暖干湿的多次波动,湖相及河流,风成为主的水上沉各佼替变化。通过对该区东露天煤矿沉积剖面113块样品进行系统孢粉百分比及浓度分析,划分出8个孢粉组合带。结合^14C测年数据,确定了该区20000年以来的气候演变序列。 相似文献
5.
宁晋泊是河北平原南部三大古湖群之一,通过LN42.5m厚沉积剖面的孢粉分析,获得古植物替达近20次,反映古气候变化具有明显减暖气候旋回5次以上,其中有2次寒冷期,3次湿暖期。结合6.4m以上^14C年龄数据推断计算更更新世与全新世界线在7.5m,这一界线与隐的群,古气候与古环境等分异界线非常吻合,因此作者推断宁晋泊的形成,发展与消亡时代相应在晚更新世早期的温暖,全新世高温期再次复兴,后被河流沉积所 相似文献
6.
通过对新疆准噶尔盆地西北缘车排子地区多口探井样品分析,见丰富的孢粉化石,建立了PiceapollisPodocarpidites-Tsugaepollenites,Parajunggarsporites-Piceaepollenites,Protohaploxypinus-Striatoabieites-Hamiapollenites三个孢粉组合。根据孢粉母体植物形态和生态特征、干湿度环境和气候环境,对其孢粉植物群反映的植被类型、干湿度类型和气候带类型进行了划分,认为晚中新世孢粉植被类型为针叶林,所处的气候环境为湿润的暖温带;早白垩世孢粉植被类型为混交林,所处的气候环境为湿润的亚热带-暖温带;晚石炭世时期其植被面貌是以阔叶植物为主,所处的气候环境为半干旱的暖温带。 相似文献
7.
天津张贵庄晚二叠世孢粉植物群 总被引:4,自引:1,他引:3
天津张贵庄SR13号钻孔原归为石盒子组的地层近顶部发现了丰富的孢粉化石,这一组合兼具上石盒子组和孙家沟组孢粉组合的特征。一方面,它与上石盒子组(特别是其上部)组合有不少共同分子,在蕨类孢子和裸子植物花粉(包括具肋花粉)的含量比例上也可以与之对比,但缺乏一些标志分子。另一方面,在属种组成上,当前组合与已知的孙家沟组合也颇可比较,而且出现了一些中生代色彩的分子。这一组合的揭示与研究有助于提高人们对华北晚二叠世晚期孢粉植物群特征的认识。依据当前组合与已知相关孢粉组合的对比讨论,将其时代定为晚二叠世,并倾向于晚二叠世晚期(对应于孙家沟组)。 相似文献
8.
山西柳林孙家沟组孢粉植物群 总被引:4,自引:1,他引:3
记述山西晚二民晚期孙家和沟组的丰富孢粉植物群,计有57属109种(包括相似种和未定种,讨论孢粉植物群的性质,:以西欧镁灰岩组分子为主体,并有相当数量的安加拉-亚安加拉(如新疆北部)成分参与,还有少量华夏植物群的残留分子。 相似文献
9.
中国晚三叠世孢粉植物群地理分区 总被引:2,自引:0,他引:2
我国晚三叠世孢粉化石十分丰富,经研究划分为南北两个孢粉植物群地理区,南方孢粉植物群自上而下由3个组合带构成:1)Micrhystrdium-Zebrasporites组合带,2)Aratrisporites-Taeniaesporites组合带,3)Kyrtomisporis-Ovalipollis组合带;北方孢粉植物群由2个组合带构成:1)Duplexisporites-Parataeniaes 相似文献
10.
11.
- 相似文献
12.
SIMON J. DAVIS 《Zoological Journal of the Linnean Society》1980,70(3):289-312
Equid remains–mostly isolated teeth–from archaeological sites in Israel are described. Particular attention is paid to dental enamel fold morphology and criteria are established tor separating several Old World Quaternary equid species. Eauus hydruntinus , which is here considered a zebra rather than an ass, was present until 12,000 bp in northern Israel, while at the same time E-asinus/hemionus inhabited the arid regions in the south. Inirequent remains of E. caballus are also described. By 4000 years ago ass, probably the domestic form, was present in northern Israel. 相似文献
13.
14.
Katleen Deckers Simone Riehl Emma Jenkins Arlene Rosen Andrey Dodonov Aleksandra N. Simakova Nicholas J. Conard 《Vegetation History and Archaeobotany》2009,18(4):329-340
Rockshelter Baaz in the Damascus region of Syria provided a variety of botanical remains from the Late Pleistocene and Early
Holocene period. These remains provide new information about the vegetation evolution in this region. The earliest occupational
levels correspond with a moisture peak during the Late Pleistocene, between ca. 34–32 kyr b.p., when pine expanded. The next occupations took place during extreme arid conditions, ca. 23–21 kyr b.p., and probably during the Last Glacial Maximum when a steppe vegetation was established. The occupation level of the Younger
Dryas, represented by Natufian remains, suggests that the area had been covered by almond-pistachio steppe, similar to later
periods of the Early Holocene, and was probably located just outside the range of dense wild cereal stands. There is no drastic
impact of the Younger Dryas visible on the vegetation in the botanical remains. The lack of fruits and seeds at Baaz indicates
that the site was more likely to have been a temporary hunting post rather than a plant processing site for much of its history.
It is ideally suited to this purpose because of its location over the Jaba′deen Pass and the associated springs. However,
archaeological remains from the Natufian period, suggest that the site was more permanently occupied during this time.
A. Dodonov deceased. 相似文献
15.
Libby W. Cowgill 《American journal of physical anthropology》2010,141(1):16-37
While a wide variety of studies have focused on population variation in adult cross‐sectional properties, relatively little is known about population variation in postcranial robusticity in immature individuals. Furthermore, the age at which the population differences readily detected in adults manifest during growth is also unknown. This research addresses these gaps in our current understanding through the analysis of immature humeral and femoral long bone strength. Cross‐sectional geometry was used to compare the developmental trajectories of diaphyseal strength in Late Pleistocene Neandertal and modern human subadults to a sample of immature humans from seven geographically diverse Holocene populations. Population differences in size‐standardized cross‐sectional properties appear to be systemic and develop very early in ontogeny in the Holocene sample. In many cases, these differences are present before one year of age. In general, the Late Pleistocene fossil samples fit within the range of recent human variation in long bone strength. Population differences detected here are likely related to a combination of factors including activity patterns, genetic propensities, and nutritional status. These results highlight the complex mosaic of processes that result in adult postcranial robusticity, and suggest that further exploration of the developmental interplay between intrinsic and extrinsic influences on skeletal robusticity will likely enhance our understanding of adult postcranial morphology. Am J Phys Anthropol 2010. © 2009 Wiley‐Liss, Inc. 相似文献
16.
A new pollen record from Lago di Vico (core V1) provides fundamental new information towards reconstruction of flora and vegetation history in central Italy during the last 90 000 years. The chronological framework is secured by seventeen AMS14C dates, one40Ar/39Ar date and tephra analyses. At the base of the pollen record, i.e. shortly after the40Ar/39Ar date 87 000±7000 B.P., three phases with significant expansion of trees are recorded in close succession. These forest phases, which stratigraphically correspond to St Germain II (and Ognon?) and precede pleniglacial steppe vegetation, are designated by the local names Etruria I, Etruria II and Etruria III. During the pleniglacial, a number of fluctuations of angiosperm mesophilous trees suggest the presence of tree refugia in the area. The lowest pollen concentration values are recorded at ca. 22 000 B.P. which corresponds with other pollen records from the region. The late-glacial is characterized by an expansion in the arboreal pollen curves that is less pronounced, however, than in other pollen profiles from Italy. The Holocene part of the profile is consistently dominated by deciduous oak pollen. No major changes in arboreal pollen composition are recorded but several marked and sudden declines of the tree pollen concentration suggest that the forest cover underwent dramatic changes. Clear evidence for human impact is recorded only when cultivated crops became important which dates to ca. 2630±95 B.P. 相似文献
17.
Paleontological Journal - Distribution of 57 ostracod species is investigated in the Quaternary sediment samples from the borehole RBH-16, drilled at the north-eastern Black Sea shelf edge off the... 相似文献
18.
J. R. DODSON 《Austral ecology》1979,4(4):419-427
The stratigraphy and pollen analysis of the basal 5.73 m of an 11.73 m core from the centre of Victoria's deepest lake is described. The hypothesis is advanced that at 16 100 B.P. a cool semi-arid environment supporting a sparse or scattered Eucalyptus–Callitris woodland with an understorey of grasses, Asteraceae and Chenopodiaceae dominated the region. From this time the lake level fell and was at its lowest between 15 000 B.P. and 10 000 B.P. At about the same time Casuarina migrated into the region as Callitris, Asteraceae and Chenopodiaceae declined. There was a period from 9600 B.P. to 9200 B.P. when Acacia and Dodonaea were common around Lake Bullenmerri, but these declined and were replaced by the Eucalyptus-Casuarina woodland with a herbaceous understorey which persisted through the Holocene period in western Victoria until it was cleared by European settlers. 相似文献