共查询到20条相似文献，搜索用时 31 毫秒
1.
Thermally transferred optically stimulated luminescence (TT-OSL) dating extends the age range beyond current limits of OSL dating in Chinese loess. In this study, we use a single-aliquot regenerative-dose procedure for TT-OSL protocol to date Yaochangwan and Hejialiang localities of loess-covered Liangshan Paleolithic sites in Hanzhong Basin, which is an important area for the study of Paleolithic industries during the middle Pleistocene in central China. The results suggest that buried culture layer at the Hejialiang locality is correlated with the last interglacial paleosol S1 in Chinese Loess Plateau, it is dated at 86.3 ± 6.4 ka. The Yaochangwan locality spans from approximate 600–100 ka and correlates with S5–S1 in the typical Chinese loess–paleosol sequences, respectively. These ages suggest that hominins already occupied the Hanzhong Basin since approximately 600 ka ago. 相似文献
2.
The fluvio-lacustrine sequences in the Nihewan Basin of North China (known as the Nihewan Formation) are rich sources of Early Pleistocene Paleolithic sites and mammalian fossils (known as the Nihewan Fauna sensu lato), which offer an excellent opportunity to investigate the evolution of early humans and land mammals in East Asia. Also abundant mammalian fossils provide clues about the general environmental and climatic setting of early humans. Among the Nihewan Fauna (sensu lato), the Daodi Fauna is one of the most complete and oldest in the eastern Nihewan Basin: seven mammalian fossil-bearing layers in the Nihewan Formation have been described. Except for a biostratigraphy, however, precise age control on the Daodi Fauna has remained unavailable. Here we report a new magnetostratigraphic record that stringently constrains its age. The seven fossil-rich layers span an age range of ca 2.5–1.8 Ma between the Gauss–Matuyama boundary and the termination of the Olduvai polarity subchron. Combining our new and recently published paleomagnetic data, we further establish a Pleistocene magnetochronology of the fauna and Paleolithic sites in the Nihewan Basin. Age ranges of about 2.5–0.5 Ma for the faunas and 1.7–0.3 Ma for the Paleolithic sites are deduced, which span most of the Pleistocene. The chronological framework and calculated proportions of mammals that were adapted to different environments indicate that mixed settings of dominant grasslands and subordinate forests continued at least from 2.5 to 0.5 Ma for early human occupation in the basin, similar to the mixed open savannah and woodland habitats of early humans in Africa. The Nihewan hominins consistently adopted a simple Oldowan-like technology (i.e., Mode 1 core and flake technologies) from at least ca 1.7 to 0.3 Ma. A more advanced Acheulean technology (Mode 2) has not been found in the Nihewan Basin, although it started to emerge in the Bose Basin of South China at ca 0.8 Ma. This implies that multiple groups of hominins distinguished by differential stone-tool-making capabilities may have coexisted in China after 0.8 Ma. 相似文献
3.
秦岭北麓晚第四纪断层陡坎的初步研究 总被引：4，自引：1，他引：4
根据航片解译和野外调查,发现在秦岭北麓第四纪松散沉积物中发育有断层陡坎,本文依据对这些陡坎的地质地貌分析、地形剖面测制、探槽揭露及测年数据,讨论了断层陡坎的空间分布和形态学特征、生成时代和断距,评估了秦岭北麓断裂在晚第四纪的活动强度。由断层陡坎高度经过校核获得断距变化范围在1.1至7.9米之间,由此求得秦岭北麓断裂中段全新世中晚期以来平均滑动速率接近1mm/a,西段在眉县一带为0.5mm/a左右。晚更新世以来,发生过3—4次古地震事件 相似文献
4.
5.
CAI Baoquan & LI Qiang . Department of History Xiamen University Fujian China . Institute of Vertebrate Palaeontology Palaeoanthropology Chinese Academy of Sciences Beijing China 《中国科学D辑(英文版)》2004,47(5)
The Nihewan (Nihowan) Basin is well known in the world for producing abundant mammal fossils and paleoliths. As one issue of the program 搕he early hominid evolution and environmental background in East Asia?a biostratigraphic survey was made in July 2001, and a large number of mammal fossils were un-earthed and 5 lithic artifacts were recognized from the Majuangou gully in the Nihewan Basin, Hebei Prov-ince, North China. 1 Stratigraphic section The new site is located on the south bank… 相似文献
6.
位于华北板块和扬子板块之间的陕西中南部由渭河盆地、秦岭造山带和汉中盆地构成,其新构造运动主要形式为山脉隆升、盆地断陷,因此以重复水准测量为手段的地壳垂直运动研究尤为重要.基于研究区1970年以来的多期精密水准测量数据,用GPS垂直运动速率约束的动态平差方法获得了区域垂直运动速度场.以此为基础,用倾滑位错模型、网格搜索方法反演了研究区主要断层倾滑速率和闭锁深度,结果显示:秦岭北缘断裂倾滑速率为2.25～4.53 mm·a~(-1),闭锁深度为7.7～10.0 km;华山山前断裂倾滑速率为2.35～2.71 mm·a~(-1);闭锁深度为2.8～5.0 km,反映了该断裂在华县大地震之后,可能还没有完全闭锁,发生大震的应变能积累条件不足;渭河盆地北缘断裂的倾滑动速率为2.0～2.5 mm·a~(-1),闭锁深度仅为3.0 km左右,说明该断裂以蠕滑运动为主;略阳断裂倾滑速率为3.02 mm·a~(-1),闭锁深度6.7 km,是陕南较活动的断裂. 相似文献
7.
The Xunhua, Guide and Tongren Basins are linked with the Laji Mountain and the northern West Qinling thrust belts in the Xunhua-Guide district. Basin depositional stratigraphy consists of the Oligocene Xining Group, the uppermost Oligocene-Pliocene Guide Group and the Lower Pleistocene. They are divided into three basin phases by unconformities. Basin phase 1 is composed of the Xining Group, and Basin phase 2 of the Zharang, Xiadongshan, Herjia and Ganjia Conglomerate Formations in the Guide Group, and Basin phase 3 of the Gonghe Formation and the Lower Pleistocene. Three basin phases all develop lacustrine deposits at their lower parts, and alluvial-braided channel plain depositional systems at upper parts, which constitute a coarsening-upward and progradational sequence. Basin deposition, paleocurrent and provenance analyses represent that large lacustrine basin across the Laji Mountain was developed and sourced from the West Qinling thrust belt during the stage of the Xining Group (Basin phase 1), and point-dispersed alluvial fan-braided channel plain deposition systems were developed beside the thrust and uplifted Laji Mountain and sourced from it, as thrusting migrated northwards during the stage of the Guide Group (Basin phase 2). Evolution of basin-mountain system in the study area significantly indicates the growth process of the distal Tibetan Plateau. The result shows that the Tibetan Plateau expanded to the northern West-Qinling at Oligocene (29–21.4 Ma) by means of northward folded-and-thrust thickening and uplifting and frontal foreland basin filling, and across the study area to North Qilian and Liupan Mountain at the Miocene-Pliocene (20.8–2.6 Ma) by means of two-sided basement-involved-thrust thickening and uplifting and broken foreland basin filling, and the distant end of Tibetan Plateau behaved as regional erosion and intermontane basin aggradational filling during the Pliocene and early Pleistocene (2.6–1.7 Ma).
相似文献8.
汉中盆地是青藏高原、 秦岭与大巴山—龙门山差异隆升区中间的新生代断陷盆地, 是重要的地质体连结点. 通过新近开展的汉中市活断层探测工作中的地面地质调查、 浅层地震勘探与钻孔联合地质剖面分析等工作认为, 汉中盆地内部存在一条活动断裂, 即梁山南缘断裂. 浅层地震勘探资料显示, 梁山南缘断裂错断多套第四纪以来的地层, 错距自下而上逐渐减小. 钻孔联合地质剖面显示, 梁山南缘断裂错断晚更新世中晚期以来的砾砂及卵石层, 距今58 ka的砾砂层错距约为6 m. 这些现象首次揭示了汉中盆地内部梁山南缘断裂的最新活动时代和活动性质. 相似文献
9.
对山西襄汾丁村文化遗址群内大柴剖面进行的磁性地层学研究表明,松山与布容的极性界线（M/B）出现在距剖面顶部45 m处;磁化率对比结果显示,此位置正好与S8上部对应.由这种极性和磁化率的对应结果可推断,下、中更新统（Q1/Q2）的地层分界也应在距剖面顶部45 m处的S8上部,而不是传统上认为的Q1/Q2的地层分界,在距剖面顶部80 m处.这种以古地磁学为基础的新的划分方案,对丁村遗址群的对比以及丁村遗址年代的最终确定都有重要的指示意义.根据其沉积环境和地层特征推断,采样部位下部的磁化率低值带应为水成黄土.而岩石磁学研究结果显示,磁铁矿、赤铁矿和热不稳定性磁赤铁矿是大柴剖面沉积物中主要的磁性矿物;磁铁矿和赤铁矿同为高温稳定性磁性载体. 相似文献
10.
The Paleolithic site of Xibaimaying (XBMY), once considered the youngest flake tool site within the Nihewan Basin, North China, is an ideal archive to study the chronological relationship between flake tool and microblade industries in the Nihewan Basin during the Upper Palaeolithic, but the previous ages obtained for the site remain controversial. From 2015 to 2019, three areas at two archaeological localities (XBMY-I and XBMY-II) of the site were excavated, and well-preserved fossils and flake tools were unearthed. In this study, a total of 26 samples were collected from the three areas for optically stimulated luminescence (OSL) dating using a single-aliquot regenerative-dose (SAR) protocol on fine-grained quartz. A shared ‘Standardized growth curve’ (SGC) for a section was constructed to reduce the time required for De estimation. The long-term weighted average water contents of the samples during their burial period were estimated based on the in-situ water contents of continuous samples from a nearby borehole. All the OSL ages were modelled via Bayesian statistics using the OxCal software, modifying the OSL ages with stratigraphic constraints in each section. The results show that the cultural layer bearing flake tool assemblages falls within the period of 122–36 ka, indicating that the flake tool industry of the Xibaimaying site is comparable to that of the Youfangbei (108–86 ka), Banjingzi (∼86 ka) and Xinmiaozhuang (75–63 ka) sites, rather than the youngest one in the Nihewan basin, which explains why the Xibaimaying site is characterized as pure flake tool culture without any ‘advanced’ trait. The OSL dating results also shed new light on the study of sedimentary processes in the Xibaimaying site area. The different deposition rates (0.01–1.61 mm/a) for the sediments at the three newly excavated areas imply complex geomorphologic processes in the site area. 相似文献
11.
六棱山北麓断裂是山西地堑系北端张性构造区中的一条控制性断裂，总体走向北东东、倾向北北西，是一条至今仍在活动的倾滑正断裂，控制阳原盆地的形成和发展。在１９９３年和１９９４年的中日合作研究中，我们对断裂分段特征进行了研究，并用Ａｕｔｏ－ｌｅｖｅｌ仪器对这一条断裂晚第四纪不同时期的断错地貌面的位错量进行了测量，对这些地貌面的年龄进行了测定，得到该断裂带晚更新世晚期至全新世时期的平均垂直滑动速率为０．４３～０．７５ｍｍ／ａ。关键词 相似文献
12.
忻定盆地周缘山地的层状地貌与第四纪阶段性隆升 总被引：2，自引：1，他引：1
忻定盆地位于汾渭地堑系北段,是一个典型的新生代张性断陷盆地,其周缘由持续隆升的断块山地围绕。断块山地的阶段性隆升在山麓地带形成了由山麓剥蚀面与河流阶地构成的6级联合地貌面,并在山区河段形成了由急流段与缓流段相间分布的河流纵剖面形态,急流河段的最高点对应阶地在上游方向上的消失点。急流段由多级跌水组成,是断层多期地表错动的结果,代表了山地快速隆升时期,而缓流河段代表了山地相对稳定期。根据河流阶地的断代以及急流河段与缓流河段的相对长度估算了山地阶段性隆升的时代,4个快速隆升期分别距今1200~1059ka,600~501ka,130~103ka,20~0ka,其间为3个相对稳定期 相似文献
13.
The Tianshan Mountains,located in the northwestern China,are bounded by the Tarim Basin to south and the Junggar Basin to north.In the north piedmont of this mountain range,ongoing thrusting and folding forms a set of roughly parallel anticlines.Geological observations predicted that averaged over last~1 Ma time scale,the shortening rates of these anticlines are about2.1–5.5 mm/a;However by averaged over about 10±2 kyr,their shortening rates reduce to merely about 1.25±0.5 mm/a.The slow shortening of the anticlines in the last~10±2 kyr is coarsely concurrent in time with the last global deglaciation.Here,we use a two-dimensional finite element model to explore crustal deformation across north piedmont of the Tianshan Mountains under various erosion-sedimentation conditions that are assumed to represent the climate-controlled surface process.Numerical experiments show that with a relatively weak erosion-sedimentation strength,the crustal shortening is accommodated mainly by north piedmont of the Tianshan Mountains,similar to the high shortening rate of anticlines averaged over the last~1Ma.By increasing erosion-sedimentation strength,the resultant crustal shortening is transformed gradually toward the Tianshan Mountains,resulting in the shortening rate in its north piedmont being decelerated to what is observed as averaged over the last~10±2 kyr.This result suggests that erosion and sedimentation could play an important role mechanically on strain localization across an intra-continent active tectonic belt.Hence,if the climate change around the last global deglaciation could be simply representative to the enhancement of surface erosion and sedimentation across the pre-existed Tianshan Mountains and its foreland,our models indicate that the observed shortening-rate variations averaged over~1 Ma and~10±2kyr time scales around north piedmont of the Tianshan Mountains should be resulted from climate changes. 相似文献
14.
15.
The Neogene sediments of Gansu Group from northwestern China contain eolian and fluvial deposits.The origins of these sediments are very important for exploring the onset of Asian inland aridification,the pattern of paleo-atmospheric circulation,and the regional tectonics and geomorphic evolution during the Miocene.Here we present detrital-zircon age spectra of typical eolian and fluvial deposits from highlands and subsidence basin,and compare them with those of surrounding eroded mountain(such as the West Qinling Mountains and Liupan Mountains)materials and Quaternary loess derived from the Asian inlands.The results reveal that(1)the detrital-zircon age spectrum of the Miocene eolian sample is remarkably different from the eroded materials of the West Qinling Mountains and the Miocene fluvial deposits from Tianshui region,but very similar to the Quaternary loess deposits.This indicates that the provenance of Miocene eolian sediments is similar with the Quaternary loess,and thus further confirms the previous conclusions that the distribution of Asian arid lands and the pattern of atmospheric circulation during the Miocene are broadly similar with the Quaternary.(2)The detrital-zircon age spectrum of the fluvial deposits(with age about 11.5 Ma)from Tianshui region is different from the eroded materials of West Qinling Mountains,but similar with that of the Liupan Mountains to the east,which may suggest that the Liupan Mountains have already been exhumed by11.5 Ma. 相似文献
16.
17.
Shenghui Deng Yuanzheng Lu Zhong Luo Ru Fan Xin Li Yi Zhao Xueying Ma Rukai Zhu Jingwei Cui 《中国科学:地球科学(英文版)》2018,61(10):1419-1439
The Yanchang Formation is extensively developed in the Ordos Basin and its surrounding regions. As one of the best terrestrial Triassic sequences in China and the major oil-gas bearing formations in the Ordos Basin, its age determination and stratigraphic assignment are important in geological survey and oil-gas exploration. It had been attributed to the Late Triassic and regarded as the typical representative of the Upper Triassic in northern China for a long time, although some scholars had already proposed that the lower part of this formation should be of the Middle Triassic age in the mid-late 20th century. In this paper, we suggest that the lower and middle parts of the Yanchang Formation should be of the Ladinian and the bottom possibly belongs to the late Anisian of the Middle Triassic, mainly based on new fossils found in it and high resolution radiometric dating results. The main source rocks, namely the oil shales and mudstones of the Chang-7, are of the Ladinian Age. The upper part of the Yanchang Formation, namely the Chang-6 and the above parts, belongs to the Late Triassic. The uppermost of the Triassic is missed in most parts of the Ordos Basin. The Middle-Upper Triassic Series boundary lies in the Yanchang Formation, equivalent to the boundary between Chang-7 and Chang-6. The Ladinian is an important palaeoenvironmental turning point in the Ordos Basin. Palaeoenvironmental changes in the basin are coincidence with that of the Sichuan Basin and the main tectonic movement of the Qinling Mountains. It indicates that tectonic activities of the Qinling Mountains are related to the big palaeoenvironmental changes in both the Ordos and Sichuan Basins, which are caused by the same structural dynamic system during the Ladinian. 相似文献
18.
祁连山山间盆地内的新生代沉积物是研究新生代以来祁连山构造演化的重要材料.本文以位于祁连山中部祁连盆地内的新生代沉积物为研究对象,利用磁性地层学方法结合碎屑颗粒裂变径迹定年方法获取其沉积时代框架,在此基础上,结合岩性变化与沉积环境变迁分析祁连山构造演化历史.野外实测剖面显示该盆地内的第三系可划分为下部砾岩组和上部砂岩组两大岩性单元.古地磁结果显示砾岩组的沉积时代约为10—14.3Ma.砾岩组沉积大约在14.3 Ma开始形成,指示祁连山14.3 Ma以来构造活动变强烈.磁组构结果显示砾石组顶部沉积形成时的受力方向与现今祁连盆地周缘断层分布所指示的应力方向一致,表明这些断层大约在10 Ma附近开始活动.我们的结果揭示祁连山中部山脉14.3 Ma以来尤其在10 Ma附近构造活动较强烈.这与过去低温热年代学所获得的祁连山山体的快速冷却年龄及祁连山两端大型盆地内的第三系所记录的构造事件发生的时间基本吻合.而砂岩组的古地磁结果并未通过褶皱检验,其古地磁记录发生了后期重磁化,无法获得地层的准确沉积年龄. 相似文献
19.
黄河断裂是银川盆地内展布最长、切割最深的一条深大断裂,也是银川盆地的东边界。由于其北段呈隐伏状,因此,该段的活动性和滑动速率长期未知,影响了对盆地演化和地震危险性的认识。文中选择具有石油地震勘探基础的陶乐镇为研究场点,以人工浅层地震勘探结果为依据,在黄河断裂北段布设了一排钻孔联合剖面,并对标志层进行年代测试,获得了断裂的活动时代和滑动速率。结果表明,黄河断裂北段在晚更新世末期或全新世有过活动,在（28.16±0.12）ka BP 以来的累积位移为0.96m,晚第四纪以来的平均滑动速率为0.04mm/a,该值明显低于南段灵武断层（0.24mm/a）;尽管向下切割了莫霍面,黄河断裂晚第四纪活动强度和发震能力均要低于切割相对浅的贺兰山东麓断裂;黄河断裂可能在新生代之前已经强烈活动并深切莫霍面,新生代以来,银川盆地的构造活动迁移分解到以贺兰山东麓断裂为主的多条断裂之上,地壳双层伸展模型可解释银川盆地现今深浅部构造活动间的联系。 相似文献
20.
The Hetao depression zone, located to the north of Ordos block, is a complex depression basin that consists of two sub-uplifts and three sub-depressions. The depression zone is subject to the regional extensional stress field driven by the Indo-Asian continental collision and the westward subduction of the Pacific Plate. The Baotou uplift that separates the Baiyanhua sub-depression and Huhe sub-depression is mainly composed of Archean gneiss and is overlaid by Quaternary sedimentary strata. The two sub-depressions are bordered by the Wula Mountains and Daqing Mountains to the north, respectively. The bedrock exhumed in Wula Mountains and Daqing Mountains consists mostly of Precambrian granitic gneiss, and the piedmont depressions are infilled by thick Cenozoic strata. The Wulashan piedmont fault and Daqingshan piedmont fault extend along the range front of Wula Mountains and Daqing Mountains, respectively. The subsidence is controlled by the two boundary faults. Previous studies have preliminarily documented the characteristics of the northwest boundary fault of Baotou uplift. Combining shallow seismic exploration, active fault mapping, and geological drilling, this paper presents a detailed study on the tectonic characteristics of the Baotou uplift.
The shallow seismic exploration reveals that the Baotou uplift is an asymmetrical wedge with a steep southeast wing and a gentle dipping northwest wing. The Baotou uplift is wider in the northeastern part and narrows down towards the southwest. In seismic profiles, the Baiyanhua sub-depression and the Huhe sub-depression manifest as asymmetric dustpan-like depressions with south-dipping controlling faults. Baotou uplift is bounded by the Xishawan-Xingsheng Fault to the northwest and Daqingshan piedmont fault to the southeast. The two faults exhibit significant difference in many aspects, such as fault geometry, fault displacement, the latest active time, and so on. The southeast boundary fault of Baotou uplift is the Baotou section of the Daqingshan piedmont fault which is a Holocene active fault and the major boundary fault of Huhe sub-depression. East of Wanshuiquan, the fault strikes EW-NEE; west of Wanshuiquan, the strike changes to NW. The Daqingshan piedmont fault appears as a south-dipping listric fault in seismic profiles whose dip decreases with depth and cuts through all the sedimentary strata in Huhe sub-depression; the fault extends along the late Pleistocene lacustrine platform at surface with prominent geomorphological evidences. The Xishawan-Xingsheng Fault is a buried high-angle normal fault that mainly dips to the northwest and strikes NE. The fault strike changes to NNE at the eastern tip. Based on the results of seismic exploration and geological drilling, the Xishawan-Xingsheng buried fault is an early to middle Pleistocene Fault capped by late Pleistocene lacustrine strata. We reckon that the Xishawan-Xingsheng Fault is one of the synthetic faults that dip towards the main boundary fault of Baiyanhua sub-depression.
Similarities in lithology, geometry, and structural characteristics of south boundary faults all indicate that Baotou uplift is the western extension of Daqing Mountains. Multiple factors may contribute to the formation of Baotou uplift, such as tectonic subsidence and the development of large-scale river system and mega-lake. We suggest that the upwelling of asthenosphere may play a primary role in the evolution of Wulanshan piedmont fault and Daqingshan piedmont fault. Separated by the Baotou uplift, the Wulashan piedmont fault and Daqingshan piedmont fault can be regarded as independent seismogenic faults. The Hetao depression zone is featured by complex inner structures, and many scientific issues are subject to further researches. Thus, more attention should be paid to the secondary structures within the depression zone for a better understanding on the formation and evolution of Hetao depression zone. 相似文献