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1.
Jie Chen Tai-bao Yang G.G. Matishov A.A. Velichko Biao Zeng Yi He Pei-hong Shi 《山地科学学报》2018,15(3):504-518
A reliable chronology is essentially critical for correlating loess records with other paleoenvironmental time series, as well as for continuing improvements in the reconstruction of paleoenvironment and paleoclimate changes. It is exactly that the scarcity of chronologies across the Sea of Azov has limited the interpretation of climatic and environmental information in the East European Plain. In view of this, this paper conducted an exploratory study to investigate whether the optically stimulated luminescence (OSL) dating of mediumgrained quartz could be used to obtain a set of chronologies and the age models could be used to establish an independent time scale since the Late Pleistocene for the Sea of Azov loess. The results showed that an internally consistent set of optical ages for the Azov loess deposited up to ~76 ka. In addition, the ages developed based on magnetic susceptibility and grain size ages models showed good comparability with independent OSL ages at an acceptable range, suggesting that it might be practicable to establish an independent time scale using age models at the Sea of Azov loess, at least for the uppermost part of the Chumbur-Kosa section. Comparison with the ages based on two age models, the grain size ages using fine-grain fractions may provide a more reliable chronological sequence at the Azov loess since the Late Pleistocene. With the help of absolute ages and climate proxies (magnetic susceptibility and grain size), paleoclimatic change in the Sea of Azov have been traced for the Late Pleistocene. 相似文献
2.
Carbonate pedofeatures were studied in details in a loess-paleosol pedocomplex near Kursk, in the central part of the European Plain. The soils studied included a modern Chernozem and five Pleistocene paleosols. Carbonate morphologies and distributions were described in the field. Various morphologies were sampled for further studies including micromorphology in thin sections and submicroscopic studies under a scanning electron microscope. The complex approach of investigation at macro-, micro-, and submicroscopic levels found that most of carbonate pedofeatures are secondary and multiphase. Many of them are related to cryogenic features. The general trend was of decreasing carbonate content in the older paleosols except for increased content in the 1St and 3rd paleosols. Most of carbonate morphologies are similar in the modern soil and paleosols, but pseudomycelium was found only in the modern Chernozem, while soft masses and impregnations are associated with the paleosols. Detailed study on carbonate attributes revealed their specific features in the modern soil and in paleosols. Veins have dissolution features under the modern environment and seem to reprecipitate in form of pseudomycelium. Coatings in paleosols at a depth of the Ist paleosol include specific fine tubes. Powdery soft masses and impregnations in the paleosols are strongly related to cryogenic fissures and paleopermafrost level. Under SEM they consist of tiny crystals, much smaller than in regular soft masses. Several types of hard concretions were identified：rounded, irregular and platy. Small concretions in the modern Chernozem have similar morphology and similar 14C-age as the rounded concretions of the upper paleosols. They are expected to represent the same generation of concretions. Platy concretions fill the bottom part of the large fissures. The 14C-age of hard concretions varies from 3310±80 yrs. B.P in the Ist paleosol up to 20 400 yrs. B.P. in the 3^rd. As a result we found the reflection of several wet-dry and cold-warm stages in carbonate morphologies and distributions. High variability of carbonates at macro-, micro- and submicroscopic levels indicates several generations and multiphase formation of carbonate pedofeatures in the loess-paleosol pedocomplex. Carbonate pedofeatures in the examined pedocomplex are more informative for the study of late Pleistocene and Holocene climatic cycles rather than characterization of a single paleosol. 相似文献
3.
Yang Zhang Guangxue Li Hongzhou Guo Yong Liu Haoyin Wang Jishang Xu Dong Ding Lulu Qiao Yanyan Ma Liyan Wang Qian Li 《中国海洋大学学报(英文版)》2018,17(5):1103-1113
We use the particle size of sediments in core YS01 A to study the sedimentary environment of the mud deposit in the central South Yellow Sea of China during late Marine Isotope Stages 3(MIS3;40.5 kyr–31.3 kyr).In addition,the East Asian Monsoon and its relationship with the North Atlantic Ocean climate change are discussed based on the sensitive grain-size calculation and the spectrum analysis.The results show that during late MIS3,the muddy area in the central South Yellow Sea experienced the evolution of coastal facies,shallow marine facies,coastal facies,and continental facies,with weak hydrodynamic conditions.Compared with other climate indicators,we found that there were many century to millennium-scale climate signals documented in the muddy area sediments in the central South Yellow Sea.According to our particle size results,three strong winter monsoon events occurred at 37.6 kyr,35.6 kyr and 32.2 kyr.The East Asian Winter Monsoon records in core YS01 A are consistent with the Greenland ice core and the Hulu cave stalagmite δ~(18)O.The millennial and centennial scale cycles,which are 55 yr,72 yr,115 yr,262 yr respectively,correspond to solar activity cycles,while the 1049 yr and 2941 yr cycles correspond to the Dansgaard-Oeschger cycles.These cycles indicate that the paleoclimate evolution of the area was controlled by the solar activities,with the high-latitude driving thermohaline circulation as the main energy conveyor belt,followed by the sea-air-land amplification of the winter monsoon variation in the central Yellow Sea in the late MIS3. 相似文献
4.
5.
Analysis of 13 spore-pollen assemblage zones reflecting environmental changes since the later middle Pleistocene showed the
seccession of paleovegetation and the paleogeographic changes in the Bohai Basin and circumjacent area. Paleoclimatic variations
here can obviously be divided into 5 cold and 5 warm periods: 2 cold and 1 warm periods in 200,000–100,000 a B.P.(late middle
Pleistocene) 3 cold and 3 warm periods in 100,000–12,000 a B.P.(late Pleistocene), and 1 warm period since 12,000 a B.P. Late
Pleistocene climate tended to become colder and colder. The coldest period was in the later stage of late Pleistocene, when
the study area was a periglacial zone. The mean annual temperature then was about 10°C lower than it is now. In the middle
stage of late Pleistocene, climate became warm; the mean annual temperature then was about 3–4°C higher than it is now.
By applying principles of climatic stratigraphy, the authors deduced through sporo-pollen analysis, that the boundary between
middle and late Pleistocene should be at 178–181 m, and that between Pleistocene and Holocene should be at 12.8 m. The results
of climatic stratigraphy are consistent with those of magnetic stratigraphy.
This paper was published in Chinese inOceanologica et Limnologia Sinica.18 (3): 253–266, 1987. 相似文献
6.
南岭及邻区的第四纪沉积以冲积物、残积物和洞穴堆积物为主,长期以来缺乏统一的地层格架和时间框架。基于剖面资料和实地调查,将南岭第四纪地层划分为永州-郴州、桂林-贺州、韶关-清远、赣州、道县-阳山等5个地层小区;通过厘定每个小区的岩石地层序列、生物地层和气候地层及其测年成果,建立了综合地层的对比格架。结果表明,南岭第四系与中国更新统泥河湾阶、周口店阶、萨拉乌苏阶和尚未建阶的全新统可一一对比;其生物地层以早更新世巨猿动物群和中更新世晚期以来的马坝人、道县人和柳江人等智人演化为特点;气候地层以洞穴石笋和高山泥炭重建的古气候记录为代表,主要反映东亚季风背景下的南岭局地气候。但由于测年数据较少,冲积层和残积层的对比仍然存在困难;生物演化阶段与气候变化之间也未能详细对比。因此,今后南岭的第四纪地层研究应围绕提高测年精度与建立统一的年代标尺开展,促进综合地层对比的精细化、延伸气候地层的时间尺度并拓展与南海海相地层的对比;这一基础性工作对水文、环境、工程等实践应用亦具有重要意义。 相似文献
7.
Middle and Late Permian palynoflora in Tianshan Township,southeast of Bogda Mountain,Xinjiang, China
The Permian is one of the most important periods during which the vegetative earth witnessed the transition from icehouse to greenhouse climate and the global environment changes. Organisms on the planet en-countered great challenge and the demise of swamp caused the extinction of arborescent lycopods and the rising of Mesophytic plants accomplished the floral transition from the Paleophytic to Mesophytic vegetation. In order to depict the climatic changes and floral succession in the middle and high latitudes of the North Hemisphere, palynological investigation was engaged, and 40 samples collected from the uppermost of Taerlang Formation, Hongyanchi Formation and Quanzijie Formation in the Tianshan Town, Turpan-Hami Basin, eastern Xinjiang, China. The result shows that the palynoflora in the studied area is composed of 50 species of 33 genera, domi-nated by disaccites and striatiti gymnosperm pollen, and characterized by diverse Protohaploxypinus, Hamia-pollenites, Alisporites and Klausipollenites. It is quite similar to those Middle and Late Permian palynological as-semblages reported in the Dalongkou section and other localities in southern margin of Junggar Basin, and aged at Middle and Late Permian. The diversity of typical Angara and sub-Angara pollen, such as Falcisporites, Alisporites, Protohaploxypinus, Vittatina, Lunatisporites, Hamiapollenites, etc. indicates that the studied palyno-flora belonged to the sub-Angara phytoprovince, while the presence of Lueckisporites virkkiae implied Euramerica pollen intruded northward sometimes. The paleoclimate of the studied area might be warm and humid with fluc-tuated dry seasons during the late Guadalupian and early Lopingian time. 相似文献
8.
Jian-hui Jin Zhi-zhong Li Yan Cheng Xiao-lin Xu Zhi-xing Li Xiao-ju Liu 《山地科学学报》2018,15(8):1777-1788
The 'Old Red Sand' is a type of semicemented medium-fine sandy sediment that is red (10R4/8) or brown red (2.5YR4/8) in colour and is found in late Quaternary deposits. The sediments have distinctive characteristics and are a critical archive for understanding climatic changes in the coastal areas of East Asia. The ages of the late Quaternary aeolian sand dunes from Haitan Island in the coastal area of South China are still in debate. In this study, three sets of marine terraces were identified in the northern region of Haitan Island. Aeolian dune sands are well preserved on the top of these terraces. Quartz Optically Stimulated Luminescence dating and the distribution of the formation ages demonstrated that the palaeo-dunes are deposits from the middle-late period of the Late Pleistocene (Q 3 2-3 ). The period may be divided into three stages, 100–90 ka, 70–60 ka, and 40–20 ka, in which the palaeo-dunes of the first two stages are more widespread and were formed separately during a low-sea level period of the Marine Isotope Stages 5b and 4. Several depositional palaeo-flood event records were preserved during the last stage due to the increasing gradient of mountain gullies formed during the Last Glacial Maximum. 相似文献
9.
Isotopic evidence for holocene climatic changes in Bosten Lake, Southern Xinjiang, China 总被引：2，自引：0，他引：2
ＩＳＯＴＯＰＩＣＥＶＩＤＥＮＣＥＦＯＲＨＯＬＯＣＥＮＥＣＬＩＭＡＴＩＣＣＨＡＮＧＥＳＩＮＢＯＳＴＥＮＬＡＫＥ,ＳＯＵＴＨＥＲＮＸＩＮＪＩＡＮＧ,ＣＨＩＮＡＺｈｏｎｇＷｅｉ（钟巍）ＸｉｏｎｇＨｅｉｇａｎｇ（熊黑钢）ＤｅｐａｒｔｍｅｎｔｏｆＧｅｏｇｒａｐ... 相似文献
10.
Desertization of the continental shelf of China in the later stage of Late Pleistocene 总被引：1，自引：0，他引：1
In the later stage of Late Pleistocene, global climate entered into the climax period of Würm when temperature decreased remarkably
and glaciers developed. Information from the East China Sea also confirm that the sea level fell by at least 130 m at that
time (Emery, 1968). The Bohai Sea and Yellow Sea at the climax period were totally exposed, while the East China Sea and South
China Sea shelf regions were exposed partly. The exposed shelf area exceeded 1 million km2 and became a salty desert where land plants could not survive. Such were the conditions which led to the desertization of
the shelf region.
Eolation was the major exogenetic force not only on land but also on the shelf region in the ice age. At the climax period
of Würm, the northern part of China developed thick layers of loess deposits. The shelf region at that time had similar climatic
conditions and sediments. Because the shelf region was not protected by vegetation in the ice age, intensive wind storms remoulded
the primarily deposited strata to produce new sedimentary differentiation and new series of land sediments. Shallow-layer
profiler records indicated the existence of many land sediment types, including dunes, dune-chains, desert bodies, thick layers
of repose angle sediments and desertization derivatives.
New data available show the shelf region adjoining China can be divided into six regions of desertization and its derivatives.
Contribution No. 1846, from the Institute of Oceanology, Acadernia Sinica.
Project sponsored by the National Natural Science Foundation of China. 相似文献
11.
Based on the δ13C and δ18O fluctuation of lacustrine carbonate, CaCO3 content and sporo-pollen data, a palaeoclimatic history of Bosten Lake during the Holocene has been outlined, several stages
of climatic changes are divided, and the following result es are obtained: (1) Palaeoclimatic changes revealed by carbonate
isotope around Bosten Lake are basically identical with that revealed by other geological records in Xinjiang. Environmental
changes presented apparent Westlies Style model: during cold period, relative humidity increased, δ18O, δ13C and CaCO3 appeared low; but in warm periods, the dry regime aggravated. (2) The temperature reflected by δ18O exist evident features being increase in the late period during the Holocene. Together with the δ13C, pollen and CaCO3 analyses, several cold and warm phases which are of broad regional significance can be identified. The warm peaks occurred
at about 11.0 ka B.P., 9.4 ka B.P., 7.5 ka B.P., 5.0 ka B.P., 3.0 ka B.P. and 2.0 ka B.P.; the cold peaks at 11.5 ka B.P.,
10.5 ka B.P., 8.8 ka B.P., 5.5 ka B.P., 3.3 ka B.P., 2.2 ka B.P. and 1.5 ka B.P.. (3) Several climatic events with the nature
of “abrupt climatic changes” are revealed in the periods of 11.0 ka B.P. −10.5 ka B.P., 9.4 ka B.P. −8.8 ka B.P., 5.5 ka B.P.
−5.0 ka B.P. and 2.0 ka B.P. −1.5 ka B.P.. (4) The results show that carbonate isotopic record of lacustrine sediment in arid
area is very sensitive to climatic changes, and may be play a very important role in understanding the features and mechanism
of palaeoclimatic changes. 相似文献
12.
Based on field investigations, laboratory analyses and 14C dating, this paper discusses the laws of the formation and development of the paleosols in the northeast region of the Qinghai-Xizang
Plateau since Late Pleistocene. The authors reconstruct basic conditions of climate, vegetation, soil and natural zones during
the three periods in which the paleosols were formed, i.e. the last interglacial of the Late Pleistocene, warm stage of Late
Glacial and the Optimum of Holocene. Finally, this paper discusses the relationship between the paleosols and the uplift of
the Qinghai-Xizang Plateau. 相似文献
13.
探槽揭示,郯庐断裂带安徽泗县徐井一带第四纪以来的新活动表现为逆断型崩积楔、张裂楔、碎裂流和地震断层。根据现场分析初步认为,中更新统沉积后,探槽所在部位先遭受挤压,晚白垩世砖红色砂岩自西向东上冲垮塌到中更新世沉积之上,形成逆断型崩积楔-1;接着发生张性断裂活动,形成开口向上的张裂楔;随后,所在部位又遭受挤压,沿张裂楔的东边界断面挤压逆冲活动产生碎屑物质上抛流动,形成逆断型崩积楔-2;其上逐步形成更新沉积,当黑土层堆积以后,再次遭受挤压,使得断面上下黑土层堆积厚度显现差异。这表明中更新统沉积以后,断裂曾先后发生挤压-引张-挤压-挤压共4次活动,最新活动在全新世早期。根据逆断型崩积楔、张裂楔和地震断层等的成因,这几次活动应属高速粘滑活动,对应几次强烈的史前地震活动事件。上述认识部分得到原态微观观测分析结果的证实。 相似文献
14.
Information on the palaeoenvironment from Late Pleistocene to Holocene in northwestern Yannan Plateau has been deduced from a study of a 28.81m-long core taken from Napahai Lake.The results from Relative Brightness In-dex(RBI) as well as those from the lithological analyses of bulk sediments,total organic carbon and granulometric analy-ses have been used to reconstruct the environmental and climatic evolution of the area.The ages were provided by three ^14C datings.The record suggested a climate fluctuation between warm-dry and cool-wet from ca.57 to 32ka B.P.which led a shallowing and swamping of the lake.The water level again increased quickly at ca.32ka B.P.,reached itˊs peak during LGM(Last Glacial Maximum,ca.18-20kaB.P.)and remained relative high until ca.15kaB.P.The high wa-ter level at LGM is attributed to cold-wet conditions.The area experienced an abrupt and unstable climatic changes dur-ing the transition period form 15 to 10ka B.P.with a dominated littoral environment.Awarm-dry climate led to the contrac-tion of the lake during the Holocene and reed-swamps became dominant..After a minor wet-cool pulse during the Late Holocene,the modern climate became to be established. 相似文献
15.
Since the late 1950’s, many Chinese scientists have explored the remains of the Quaternary glaciation in the Qinghai-Xizang
(Tibet) Plateau and its surrounding mountains. In the main, 3–4 glaciations have been recognized. The largest one occurred
in the Late Middle Pleistocene with piedmont glaciers, ice caps and trellis valley glaciers in many high peak regions. But
here is no evidence of a unified ice sheet covering the whole plateau as described by M. Kuhle. Due to the further uplifting
of the Himalayas and Qinghai-Xizang Plateau the climate became progressively driver, diminishing the extension of glaciers
during the Late Pleistocene. The elevation of the snow line during the Last Glaciation was about 4,000 m on the south, east
and northeast edges of the plateau and ascended to 5500 m on the hinder northwest of the plateau. The thermal effect of the
big plateau massif, the sharp increase of aridity from the southeast rim to the northwest inland area and the abrupt decrease
of precipitation during the Ice Age largely account for the distribution of the Quaternary glaciers in the Qinghai-Xizang
Plateau. The neglect of Chinese literature may be one of the causes accounting for M. Kuhle’s misinterpretation on the environment
of the Quaternary glaciations in the Qinghai-Xizang Plateau. 相似文献
16.
通过礼乐盆地构造-地层-沉积分析，查明了其构造演化及沉积充填特征，揭示了其与南海扩张事件的成因联系，为南海边缘海演化研究提供了参考。研究结果表明:礼乐盆地新生代构造-沉积演化经历了3个差异显著的阶段，即古新世-早渐新世陆缘裂陷-滨浅海碎屑岩沉积阶段、晚渐新世-早中新世裂离漂移-浅海碳酸盐岩沉积阶段、中中新世以来周缘前陆挠曲沉降-区域差异沉积阶段。古新世-早渐新世，古南海向东南俯冲，华南古陆陆缘因水平引张力作用发生被动裂陷，形成礼乐盆地；此时以滨浅海环境为主，受碎屑物源供给控制，在盆地西北部发育一系列规模相对较大的辫状河三角洲，礼乐盆地东部、南部邻近古南海，仅在孤立隆起边缘发育规模较小的扇三角洲。晚渐新世-早中新世，古南海持续俯冲，新南海扩张，礼乐-巴拉望地块裂离华南古陆，向南漂移，盆地沉降缓慢，断层活动弱；此时以浅海-半深海环境为主，碎屑物源匮乏，盆地北部发育大型碳酸盐岩台地和生物礁，南部总体为半深海环境。中中新世以来，新南海扩张停止，礼乐-巴拉望地块向菲律宾岛弧俯冲碰撞，礼乐盆地进入周缘前陆期，以非对称挠曲沉降为特点，水深增大，断层活动增强；此时以半深海-浅海为主，盆地北部总体以碳酸盐岩台地和生物礁为特色，盆地南部局部发育深水重力流沉积。礼乐盆地构造-沉积演化与古南海俯冲-消亡、新南海扩张-关闭过程密切相关。 相似文献
17.
大连地区碳酸盐岩分布广泛 ,裂隙溶洞发育 ,洞穴堆积物中蕴含了丰富的更新世哺乳动物化石和古文化遗物 ,在境内陆地和附近海域陆续发现了 30余处化石点。在众多的化石点中尤以古龙山遗址和大连动物群最引人注目 ,前者在同一地点内采集到 377种上万件的脊椎动物骨骼化石 ,并伴有石器、骨器、灰烬等远古人类活动的遗物 ;后者包括了 2 8种早更新世的小型哺乳动物 ,这是大连乃至东北地区的首次报导。这些事实说明了东北地区不只是仅有晚更新世的动物群 ,至少还有早更新世的大连动物群 ,即使在晚更新世 ,也不只是单一的披毛犀 -猛犸象动物群 ,还存在着具有从华北向东北过渡性质的古龙山动物群。今后工作中应注意寻找古人类及中更新世的哺乳动物化石 ,加强对全新世动物遗骨的研究。 相似文献
18.
There widely occur stretches of permafrost at more than 3,800-4,200 meters above sea level in the source area of the Huanghe (Yellow) River. The periglacial geomorphology develops quite well, including frozen disintegration geomorphology, freezing and thawing geomorphology in cold environments, periglacial dune, buried ices and fossil periglacial phenomena. In light of the relation between stratigraphy and periglacial phenomena, three periglacial periods can be divided, which are the Middle Pleistocene periglacial period, the Late Pleistocene periglacial period and modern periglacial period. 相似文献
19.
王建力 《中国地理科学(英文版)》1998,8(1):85-90
ＴＨＥＡＮＩＳＯＴＲＯＰＹＯＦＬＯＥＳＳＭＡＧＮＥＴＩＣＳＵＳＣＥＰＴＩＢＩＬＩＴＹＩＮＴＨＥＮＯＲＴＨＥＡＳＴＥＲＮＦＲＩＮＧＥＯＦＱＩＮＧＨＡＩＸＩＺＡＮＧＰＬＡＴＥＡＵＡＳＡＮＩＮＤＩＣＡＴＯＲＯＦＰＡＬＡＥＯＷＩＮＤＤＩＲＥＣＴＩＯＮＷａｎ... 相似文献
20.
Wang Jianli 《中国地理科学(英文版)》1997,8(1):85-90
Estimates of the palaeo-subaerial wind direction were studied systematically for the first time by using the anisotropy of
loess magnetic susceptibility (AMS) measurements in the northwestern China. One hundred and forty undisturbed oriented aeolian
loess samples were collected from Lanzhou, Linxia and Wudu areas for AMS measurements, which indicated the subaerial wind
directions were not the same while the loess deposited. From the Early Pleistocene to Middle Pleistocene till Late Pleistocene,
the wind direction experienced an anticlockwise rotation in the studied area. We suggested this change was related to the
uplift of the Qinghai-Xizang Plateau and the adjustment of current and landform effects. 相似文献