首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 468 毫秒
1.
Ongoing micromorphological studies in several prehistoric sites of Greece (Theopetra cave, Boila rockshelter, Alonnisos, Drakaina cave, Kouveleiki cave, Lakonis cave complex, and Dispilio lake dwelling) provide new information on the relationship between environmental changes and the cultural history of the sites. The frequent climatic oscillations during the last glacial directly influenced the occupational mode of Theopetra cave and Boila rockshelter in northern Greece. Soil micromorphology may be a promising tool in unraveling differences in the occupational history due to climatic changes among diverse areas of Greece. Some preliminary observations from the Lakonis cave complex, in southern coastal Greece, support the existence of such differences. Evidence brought forward with the micromorphological study of Dispilio lake dwelling and Theopetra cave suggests that during the Holocene, aridification phases evident in the Mediterranean region might have also played a role in the Greek prehistoric settlement pattern. So far, evidence for aridification phases is present for the end of the Mesolithic and probably for part of the Final Neolithic. In several cases, micromorphology has revealed details of the cultural nature of the sites. Questions related to occupational intensity (Theopetra, Lakonis, Kouveleiki, and Drakaina caves), post‐depositional changes and cultural modification of the sediments (Alonnisos, Theopetra, and Drakaina caves), constructions (Theopetra and Drakaina caves), and stratigraphic correlation (Boila) have been satisfactorily addressed along with the analysis of the microstructure of the sediments. © 2002 Wiley Periodicals, Inc.  相似文献   

2.
王华  杨琰  张会领 《地球学报》2005,26(Z1):205-208
桂林地区曾是古人类活动活跃的地区,据可以断代的古人类洞穴遗址统计,发现桂北地区大部分的洞穴遗址其年代的下限都在距今约7000a 左右,此后古人类离开了洞穴,史前文化也随之发生了重要改变。影响古人类演化的因素鹅很多,究竟是什么原因驱使古人类离开洞穴,改变生活习性,这一问题一直都是困扰考古学界的难题。本文通赤研究桂北地区洞穴遗址的堆积特点,结合洞穴沉积-堆积物的特征及其孢粉记录的古气候信息,探讨了季风气候变化对桂林地区古气候变化的影响作用和气候演变历史,揭示了桂林地区全新世以来的季风气候变化时间序列和突变事件以及对古人类生存环境的影响。距今7000a 左右为中全新世气候适宜期,东亚夏季风强盛,气温升高,桂林地区的降雨增多,一方面由于地下河水位升高,淹没了穴居洞穴,其次是由于降雨增多,导致洞穴湿度增大,从而迫使古人类搬出洞穴。  相似文献   

3.
广西柳州白莲洞遗址的铀系年龄   总被引:9,自引:0,他引:9  
因涵盖新—旧石器过渡、出土人类化石及别具一格的石制品 ,广西柳州白莲洞遗址对古人类和石器文化的研究具有重要意义。新生碳酸盐岩铀系测年的结果表明 :该遗址新—旧石器间的过渡期不超过 3ka± ,短于基于钙板 1 4 C测年得出的 6 ka± ;西 6层钙板和石笋的 2 3 0 Th年龄为 16 0 ka± ,西 7层人牙化石的年代应大于此值 ;“白莲洞式”石片打制法呈清晰的演化脉络 ,时间跨度至少为 15 0 ka。邻近的柳江人地点和土博前洞铀系测年结果与本文一致。这些地点年代位置的大幅度前移 ,是我国晚更新世人类遗址已有年代框架被总体压缩的例证。具现代解剖特征的智人在中国出现的年代很可能比原认为的早得多  相似文献   

4.
Radiocarbon sequences from some northern Mediterranean cave sites show a temporal gap between Mesolithic and Neolithic occupations. Some authors regard this as a regional phenomenon and have sought to explain it in terms of a general population decline in the late Mesolithic, which facilitated the replacement of indigenous foragers by immigrant farmers. New evidence from the rockshelter site of Mala Triglavca, in Slovenia, leads us to question this view. We describe the deposits in the rockshelter and discuss the results of AMS radiocarbon dating of bone samples recovered in excavations in the 1980s. New archaeological investigations and associated soil/sediment analyses show that in the central part of the rockshelter a well‐defined stratigraphic sequence can be established, despite post‐depositional modification by soil forming processes. There is also evidence of substantial post‐depositional disturbance of the cave sediments by human agency and geomorphological processes, which have created “temporal gaps” and “inversions” in the radiocarbon sequence. The relatively large series of radiocarbon dates obtained enables some of the post‐depositional processes to be identified. © 2008 Wiley Periodicals, Inc.  相似文献   

5.
河北省崆山白云洞发育在以中寒武统张夏组为主的碳酸盐岩地层中,平面形态主要受NNW向、NE向和近EW向断裂控制,垂向上可分为3层,各层洞穴以沿陡倾断裂侵蚀、溶蚀而成的通道相连.第一层厅堂状溶洞(天堂、人间和地府)沿NNW向断裂展布,形成于早更新世中晚期;第二层格网状洞穴(迷宫和龙宫上部)沿NNW.和NE向断裂发育,形成于中更新世中期—晚更新世初;第三层形态曲折的廊道形洞穴(龙宫下部)主要追踪NE和NNW向断裂延伸,形成于晚更新世晚期—早全新世初期.在白云洞形成发育过程中,曾经历了多次构造运动破坏.现今的白云洞,景观损毁、岩石破裂严重,灾害承受力低,因此洞穴结构稳定性保护和洞穴地质环境治理是当前重要而紧迫的任务.  相似文献   

6.
Geoarchaeological research on the sedimentary fill of rockshelters and caves in the Gebel Qara (Dhofar, Southern Oman) has revealed the onset of heavy rains at 8700 yr B.P. These rains, produced by strengthening of the Southwest monsoon, abruptly altered the dry environment dominant in the area since the Pleistocene‐Holocene transition. Comparison of cave fills from the southern and northern fringes of the Gebel Qara indicates that the monsoon effects were limited to the southern and central part of the mountain range, directly facing the sea, and did not penetrate into the Nejd Desert. © 2005 Wiley Periodicals, Inc.  相似文献   

7.
Olahola is a wavecut cave positioned well above the postglacial marine limit. The sediment sequence in the cave can be litho- and magnetostratigraphically correlated with the sequence in the Skjonghelleren cave, 36 km northeast of this locality. Three boulder formations in Olahola represent three ice-free periods (including the Holocene) and two formations of laminated clay represent periods of ice-cover. Paleomagnetic excursions in the laminated clays have been correlated with the Lake Mungo/Mono Lake excursion (28 ka), and with the Laschamp excursion (43 ka), but the resolution of these events is much better in the caves than anywhere else. The paleomagnetic records from Skjonghelleren and Olahola suggest that during the Laschamp excursion at least 0.75–1 m of sediment accumulated in Skjonghelleren before sedimentation started in Olahola, indicating also an earlier ice coverage at Skjonghelleren.  相似文献   

8.
M. Fuchs   《Quaternary Research》2007,67(3):349-356
Soil erosion is a natural geomorphological process, which can be triggered by both natural (climate, tectonics, or both) and anthropogenic (e.g., agriculture) perturbation of the ecosystem. Evidence has accrued that the Holocene climate experienced large fluctuations in amplitude and suggestions of human impact on the ecosystem provided by the Neolithic revolution dating back to the early Holocene have been made. The question of whether man or climate was the dominant factor responsible for Holocene soil erosion remains unresolved. To resolve the reasons for Holocene sediment redistribution, high-resolution chronometric data on sediments derived from colluvial and alluvial archives from southern Greece were obtained and combined with available archaeological and paleoclimatic data from the eastern Mediterranean. These data show a significant correlation between sedimentation rates and settlement history. Climatic fluctuations are only weakly correlated with sedimentation history. The results show high sedimentation rates during the Early Neolithic (7th millennium BC) in southern Greece, suggesting that Holocene soil erosion was triggered by human activity and then amplified by enhanced precipitation. This would explain the high sedimentation rates during the Early Neolithic in connection with enhanced precipitation in the eastern Mediterranean, which continued until the mid-Holocene.  相似文献   

9.
塔里木盆地早海西期多期次风化壳岩溶洞穴层   总被引:25,自引:5,他引:20  
洞穴层是识别多期次岩溶旋回的标志,是岩溶旋回连接沉积旋回及周期性海平面变化的纽带。本文通过古地貌恢复,将从钻井剖面中识别的洞穴层归位到早石炭世古地貌剖面中,根据洞穴层总是沿稳定古潜水面发育的特点划分对比洞穴层。通过洞穴层的形成条件、充填结构分析,推断洞穴层发育序次、洞穴层与其同时期形成的沉积地层的时空对应关系,并据此对洞穴层进行盆地范围内跨地区对比、总结斜坡及岛屿两种不同的洞穴层发育模式。研究结果表明,在早海西期,塔北、塔中、和田古隆起中、下奥陶统碳酸盐岩陆块内部发育了3个期次的风化壳岩溶洞穴层,其序次为下老上新,它们是在早石炭世间歇性海平面上升过程中形成的,其同时期形成的沉积地层分别为下石炭统东河砂岩段、生屑灰岩段、下泥岩段中上部。洞穴层内部多旋回“坍塌角砾-地下河沉积”组合是斜坡内陆区潜流面的迟后上升效应,洞穴层与洞穴等时层的时空对应关系对于大型古岩溶事件的断年及洞穴层的分布预测具有重要意义。  相似文献   

10.
Black coloured laminae have been detected inside speleothems from nine caves situated in the Kraków-Wieluń Upland. The black colour results from the occurrence of charcoal particles and organic compounds. These particles originated inside the caves during wood combustion caused by prehistoric human activity. The ultrastructures of charcoal particles prove that most originated in temperatures ranging from 400 up to 600°C, suggesting that the charcoal is connected with domestic fires rather than torches. Although the laminae are proof of human activity in the caves, the occurrence of one particular lamina cannot be associated with a single episode of human occupation. It is due to the fact that depositional processes and corrosion control the number and thickness of the laminae discussed. The presence of black coloured laminae within the studied Holocene speleothems indicates that the investigated caves were settled in the Neolithic, the Bronze Age and later periods. This is consistent with the former archaeological data.  相似文献   

11.
New data and a review of historiographic information from Neolithic sites of the Malaga and Algarve coasts (southern Iberian Peninsula) and from the Maghreb (North Africa) reveal the existence of a Neolithic settlement at least from 7.5 cal ka BP. The agricultural and pastoralist food producing economy of that population rapidly replaced the coastal economies of the Mesolithic populations. The timing of this population and economic turnover coincided with major changes in the continental and marine ecosystems, including upwelling intensity, sea-level changes and increased aridity in the Sahara and along the Iberian coast. These changes likely impacted the subsistence strategies of the Mesolithic populations along the Iberian seascapes and resulted in abandonments manifested as sedimentary hiatuses in some areas during the Mesolithic–Neolithic transition. The rapid expansion and area of dispersal of the early Neolithic traits suggest the use of marine technology. Different evidences for a Maghrebian origin for the first colonists have been summarized. The recognition of an early North-African Neolithic influence in Southern Iberia and the Maghreb is vital for understanding the appearance and development of the Neolithic in Western Europe. Our review suggests links between climate change, resource allocation, and population turnover.  相似文献   

12.
River valleys have always been attractive places for human occupation. The history of Mesolithic and Neolithic floodplain occupation is linked with archives of fluvial evolution, in particular the intricate relationships between palaeo-hydrological regimes, ecological development and sedimentary environments. This paper describes floodplain evolution in the Russian forest lowland around Moscow since the last deglaciation. Although there is an obvious climatic driving force for the initial fluvial incision at the end of the last glacial, there are many arguments pointing to complex intrinsic evolution involving successive pedogenesis, floodplain accumulation, flooding and fluvial incision from the beginning of the Holocene towards recent times. Increasing wetness during the early and middle Holocene forced people to move from the lowest parts of the valley towards its edges until ultimately, during the most severe flooding episode (at around 2600 years BP), they had to abandon the valley altogether.  相似文献   

13.
People who exploit marine resources choose among them according to technological, economic, and social considerations. Prehistoric selectivity in their exploitation has often been postulated, but can be established only by comparing the archaeological record with an estimate of the kinds and quantities available in the environments of the time. Only then can those factors be considered that might have influenced their choice, a subject which is the domain of the archaeologist. In Franchthi Cave, a thick Upper Paleolithic through Neolithic sequence (ca. 23,000–5000 yrs B.P.) of occupational deposits has been excavated. As might be expected at a site now only a few meters from the sea, this sequence has yielded ample evidence for the use of marine resources, though only from ca. 11,000 B.P. onward. Moreover, the marine molluscan record exhibits drastic changes in composition over time, implying either major variation in availability or selective collecting. A marine geophysical study supplemented by an examination of present shore environments in the area has permitted the reconstruction of the changing coastal environments since ca. 20,000 B.P., thus providing an estimate of the probably available shellfish resources. Comparison with the molluscan assemblages found in the cave demonstrates that only during the latest Paleolithic and most of the Neolithic were the collected shellfish reasonably representative of what should have been available in the area. At other times the inhabitants made highly specialized, seemingly idiosyncratic choices from the spectrum of available species.  相似文献   

14.
重庆丰都雪玉洞群包括羊子洞、雪玉洞和水鸣洞,西南大学的研究团队从2008年开始对雪玉洞群开展了系统的现代过程监测,以了解洞穴系统气候和环境信息的传输、转化和记录过程。通过对雪玉洞洞穴内外的大气、植被、土壤、基岩、滴水和洞穴沉积物等的动态监测,研究了碳酸盐沉积过程的水化学指标变化,揭示了现代洞穴滴水的影响因素和变化过程,以及碳酸盐沉积物对现代气候环境变化的响应,也为古气候的定量化研究提供了基础支撑。现代过程监测记录表明:雪玉洞CO2主要来源于上覆土壤,其季节变化受降水的影响较大;在短时间尺度上受到游客旅游活动的影响明显,但幅度远远小于自然过程引起的变化。雪玉洞内次生沉积物的沉积速率具有明显的旱季、雨季特征,不同滴水点下方沉积物的沉积速率变化较大。雪玉洞群三个洞穴的石笋古环境记录研究表明,本区石笋的230Th/232Th比值较适合高精度铀系测年;部分石笋沉积速率较快,平均沉积速率达到0.25 mm·a?1,可以开展高分辨率的气候和环境变化研究。羊子洞YZ1石笋的年龄范围在116~3 ka B.P.之间(平均测年精度2σ,269年),覆盖了整个末次冰期,δ18O和δ13C的变化曲线和东亚季风区的其他记录具有明显的一致性。同位素测试的时间分辨率平均为88年,成功记录了一些百年-千年尺度的气候突变事件,如Heinrich事件、7.2 ka事件、小冰期等。在精确年代学的基础上,雪玉洞群石笋具有重建高分辨率气候环境变化的潜力。   相似文献   

15.
The Shangqiu area, situated on the alluvial plain of the lower Yellow River, is traditionally considered the center of the predynastic and early Shang culture. Archaeologic remains dating to predynastic and dynastic Shang periods, however, have remained elusive. The current pattern of Neolithic and Bronze Age sites is characterized by their upland settings; and it has been often assumed that the area had the same landscape from the Neolithic through recent historic time. The potential impact of geomorphic processes on these early sites has been hardly considered in developing archaeologic models of temporal and spatial distribution of these sites. This article first presents a reconstruction of the Holocene floodplain history in the archaeologically significant area. On the basis of stratigraphy and sedimentology, a Holocene landscape evolution model is constructed to explore the interrelationship between evolving landscape and archaeologic record of the Neolithic and Bronze Age. The prolonged landscape stability from very late Pleistocene or early Holocene to 2000 yr B. P. provided potential Neolithic and Bronze Age human occupation with a favorable physical environment. After 2000 yr B. P., the hydrologic regime changed and the floodplain experienced 2-3 m of gradual vertical accretion during the following millennium. In response to the dramatic change of hydro-logic regime after the early 12th century A. D., a new floodplain formed by dominantly overbank deposition, and the old floodplain surfaces are covered by as much as ten meters of the younger alluvium. As a result, a pronounced effect has been imposed on the preservation, visibility, and discovery of the Neolithic and Bronze Age sites, including those sites of predynastic and early Shang phases. Thus, much difficulty has been imparted to our understanding of the configuration of these early archaeologic sites. This study demonstrates the usefulness of landscape reconstruction in developing settlement models of Neolithic and Bronze age sites in the area.  相似文献   

16.
长江三角洲地区全新世环境变化与人类活动的影响   总被引:4,自引:4,他引:0       下载免费PDF全文
长江三角洲地区全新世气候和环境曾发生过大的变迁,新石器时代文化伴随着全新世气候最暖期的到来,以及三角洲的形成和发展而出现,并由此向前推衍,奠定了以稻作农业为基础的经济形态。通过研究本区与农作物相关的现代植物花粉形态和代表性表土花粉,揭示出部分用于指示人类活动的综合指标、不同植被带表土花粉的组合特征和用于半定量界定不同植被类型的比值区间。研究区自然区域全新世孢粉反映当时植被3个主要发展阶段,即亚热带常绿-落叶阔叶混交林(11000~9500cal.aB.P.)、中亚热带常绿阔叶林(9500~3900cal.aB.P.)和次生性质的亚热带针阔叶混交林(3900cal.aB.P.以来),其中8000~3900cal.aB.P.为全新世大暖期的鼎盛期,3900cal.aB.P.以来人类活动明显增强。人类活动区绰墩遗址孢粉植物群,反映新石器各主要文化期都以亚热带含针叶植物的常绿-落叶阔叶混交林为地带性植被,遗址周围一般都有较大面积的水域分布;  人类对植被的干预只是在后期才开始明显增强。区内人类文化几经兴衰,主要受制于环境的变迁,包括气候和地理状况的变化,以及由此产生的海平面升降和植被变化等。与此同时,人类活动的影响随着时间的推移而日趋加重,成为一种新的环境影响因素。  相似文献   

17.
The late Pleistocene and Holocene sedimentary stratigraphy is described for part of the high plateau of Yemen (altitude 2000–3000 m A.S.L.), to the south of Sana'a. The presence of angular slope debris and dune sand in pre-Holocene contexts suggest cold and arid late Pleistocene conditions, followed, after a phase of indeterminate semiarid fluvial activity, by the development of humic palaeosol A horizons at a wide range of altitudes. Dated to between 7500 and 4350 B.P., this palaeosol includes a valley floor component related to marsh and lake development. Correlation with the humid Neolithic phase of southern Arabia is suggested for this palaeosol. Above the palaeosol thick sedimentary accumulations are associated with increased evidence of human activity and the construction of terraced fields after around 4300 B.P. © 1997 John Wiley & Sons, Inc.  相似文献   

18.
Analyses of sediment cores from Jellybean Lake, a small, evaporation-insensitive groundwater-fed lake, provide a record of changes in North Pacific atmospheric circulation for the last ∼7500 yr at 5- to 30-yr resolution. Isotope hydrology data from the southern Yukon indicate that the oxygen isotope composition of water from Jellybean Lake reflects the composition of mean-annual precipitation, δ18Op. Recent changes in the δ18O of Jellybean sedimentary calcite (δ18Oca) correspond to changes in the North Pacific Index (NPI), a measure of the intensity and position of the Aleutian Low (AL) pressure system. This suggests that δ18Op variability was related to the degree of fractionation during moisture transport from the Gulf of Alaska across the St. Elias Mountains and that Holocene shifts were controlled by the intensity and position of the AL. Following this model, between ∼7500 and 4500 cal yr B.P., long-term trends suggest a predominantly weaker and/or westward AL. Between ∼4500 and 3000 cal yr B.P. the AL shifted eastward or intensified before shifting westward or weakening between ∼3000 and 2000 cal yr B.P. Rapid shifts eastward and/or intensification occurred ∼1200 and 300 cal yr B.P. Holocene changes in North Pacific atmospheric circulation inferred from Jellybean Lake oxygen isotopes correspond with late Holocene glacial advances in the St. Elias Mountains, changes in North Pacific salmon abundance, and shifts in atmospheric circulation over the Beaufort Sea.  相似文献   

19.
中全新世持续近600年的湖北神农架石笋年纹层*   总被引:3,自引:1,他引:3       下载免费PDF全文
根据湖北神农架青天洞QT9石笋ICP-MS测年和纹层计数结果,建立了约6.7~6.1kaB.P.期间连续发育近600年石笋年纹层时间序列。年纹层厚度平均300μm,在数十年尺度上,变幅达350μm。在紫外、透射和反射3种光照条件下,年纹层呈现基本对应的季节性反差特征。年纹层厚度与原始灰度序列在数十年尺度旋回上呈现较为一致变化规律,表明暗色物质与年层生长速率共同响应于某一洞穴气候环境因子。基于中国东部不同气候期洞穴石笋年层具有的显微结构共性研究,推测这一共性是洞穴外部气候要素与洞穴内部环境耦合作用的结果。年层厚度与原始灰度两个序列的功率谱分析揭示50a,24a,9.1a以及2~7a等周期成分,其中,5.9a,4.2a和3.3a共同周期的存在,暗示中全新世存在不同频率的ENSO事件。  相似文献   

20.
辽宁海城小孤山遗址是我国北方地区重要的更新世末期-全新世人类遗址,记载着从更新世末期到全新世人类的体质及文化特征的演化历史。对1983年在此遗址发现的距今约5000年左右的、新石器时代晚期的人类头骨进行了研究,该头骨是迄今在辽宁地区发现的惟一较为完整的新石器人类遗骸,为探索早期人类体质特征的变异提供了重要的研究材料。研究显示,小孤山人类遗骸为30岁左右的男性个体。通过与更新世晚期、新石器时代及青铜铁器时代人类头骨的比较,发现小孤山人具有蒙古人种的形态特点,大部分特征与现代人相同,少数特征如颅长和颅容量,位于现代人变异范围的上限,而与更新世晚期人类接近。小孤山人非常低矮的上面部和鼻部,使其具有独特的头骨形态特点而差异于其他全新世头骨。15组头骨样本的主成分分析结果显示,新石器时代人类体质特征的变异非常大,难以将小孤山人的体质类型归入南方或北方类型,提示有必要对我国古代人类体质特征的分型问题作进一步探讨。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号