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1.
《山地科学学报》2021,(4)
In an earlier study of the Diexi ancient dammed lake along the Minjiang River in Southwest China, 10 disturbed layers with envelope and flame structures were found in more than 240 m of lacustrine sediments. In this paper, the soft-sediment disturbances caused by earthquakes in the Diexi ancient dammed lake were studied based on field investigations and laboratory core observations. A two-to three-degree-of-freedom spring-type earthquake simulation vibration table was used to carry out disturbance tests on lacustrine sediments under different dynamic conditions. The results support the following conclusions:(1) The disturbance layers in the lacustrine sediments were caused by strong earthquakes in the region.(2) The characteristics of the disturbance layers are related to the seismic parameters and the degree of sediment consolidation.(3) The greater the earthquake intensity is, the greater the disturbance amplitude is; moreover, the lower the consolidation degree is, the greater the disturbance amplitude.(4) The simulation tests verify that the disturbance layers in the sediments of the Diexi ancient dammed lake correspond to strong earthquakes in the region. These results are valuable for ongoing palaeoseismic research in the region. 相似文献
2.
《山地科学学报》2020,17(10):2497-2511
The Diexi ancient dammed lake is in the upper reaches of the Minjiang River. Six terraces with lacustrine sediments occur at the base. These terraces are the products of the graded outburst of the Diexi ancient dammed lake. The outburst of the ancient dammed lake would certainly have had an impact on the Chengdu Plain in the lower reaches of the Minjiang River. In this paper, on-site sampling and laboratory analysis were used to analyze the sediments of the Diexi ancient dammed lake and the Jinsha site in Chengdu Plain, and the environmental indicators of each sediment layer were tested. Through a comparative analysis of the environmental indicators in the sediments at the two locations, the following results were obtained: the palaeoclimatic and palaeoenvironmental characteristics at the two locations generally show consistent changes. The most important finding is that the types and content of the major pollen taxa at the two locations are similar. The Pinus content strongly proves that the soil layers at the Jinsha site was sourced from the upper reaches of the Minjiang River. Considering that the demise of the ancient culture at the Jinsha site occurred close in time to the outburst of the ancient dammed lake, this similarity suggests that the cultural change at the Jinsha site may have been related to the outburst of the Diexi ancient dammed lake. 相似文献
3.
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
4.
国内外有关卫星热红外异常与地震关系的文献已有许多 ,但大部分是探讨或研究震源区地表及上空产生增温异常现象。天线附近背景噪声和强震前后形成的电磁波与卫星数据传输载波产生随机共振 ,造成卫星图像中出现特殊异常现象 ,这种异常与强震具有非常明显的对应关系 ,通过进一步研究 ,可以开拓电磁波随机共振应用的新领域进行短临地震预报。 相似文献
5.
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
6.
Sedimentary sequence and sediment provenance are important factors when it comes to the studies on marine sedimentation. This paper studies grain size distribution, lithological characteristics, major and rare earth elemental compositions, micropaleontological features and ~(14)C ages in order to examine sedimentary sequence and sediment provenance of the core BH6 drilled at the mouth of the Yellow River in Bohai Sea. According to the grain size and the micropaleontological compositions, 4 sedimentary units have been identified. Unit 1(0–8.08 mbsf) is of the delta sedimentary facies, Unit 2(8.08–12.08 mbsf) is of the neritic shelf facies, Unit 3(12.08–23.85 mbsf) is of near-estuary beach-tidal facies, and Unit 4(23.85 mbsf–) is of the continental lake facies. The deposits from Unit 1 to Unit 3 have been found to be marine strata formed after the Holocene transgression at about 10 ka BP, while Unit 4 is continental lacustrine deposit formed before 10 ka BP. The provenances of core BH6 sediments show properties of the continental crust and vary in different sedimentary periods. For Unit 4 sediments, the source regions are dispersed while the main provenance is not clear, although the parent rock characteristics of a few samples are similar to the Luanhe River sediments. For Unit 3, sediments at 21.1–23.85 mbsf have been mainly transported from the Liaohe River, while sediments above 21.1 mbsf are mainly from the Yellow River and partially from the Liaohe River. For Unit 2, the sediments have been mainly transported from the Yellow River, with a small amount from other rivers. For Unit 1, the provenance is mainly the Yellow River catchment. These results help in better understanding the evolution of the Yellow River Delta. 相似文献
7.
According to palaeoclimatic and modern instrumental data, numerous studies have indicated that the Arctic climate has undergone a significant warming during the past 100 years, and this may lead to significant impact on the fragile lake ecosystem. In this study, we collected a lake sediment core from the Ny-(A)lesund of Svalbard and determined the concentrations of four pigments including chlorophyll derivatives, total carotenoids, oscillaxanthin and myxoxanthophyll in the sediments. Combined with other physical and chemical proxies such as calcium carbonate, total organic carbon, biogenic silicon etc., we have reconstructed the historical changes of lacustrine primary productivity in Ny-(A)lesund, especially for the past 100 years. The results showed that during the period of Little Ice Age (LIA), the climate was unfavorable for the growth of the lake algae, and thus the lacustrine productivity declined. This result was supported by the relatively low contents of pigment and biogenic silica in the sediments. In contrast, the contents of total organic carbon (TOC) and sediment pigments increased significantly in the upper 5 cm (~1890AD), reflecting the rapid growth of the lake algae, thus the great increase of lacustrine primary productivity, corresponding to the warming climate after LIA. However, the biogenic silica in the upper sediments still had a relatively low level, and this might be related to the growth competition with other algae species. Over the past 100 years, the ratio of Osc/Myx in the sediments decreased continuously, indicative of durative increase of myxoxanthophyll in blue-green algal pigments, and this might imply that the human activity had enhanced the nutrition level of the lake in the Arctic region. 相似文献
8.
Heavy metal research in lacustrine sediment： a review 总被引：2，自引：0，他引：2
Heavy metals are released into environment from a wide range of natural and anthropogenic sources. Aquatic ecosystems are normally at the receiving end and in many cases, with lakes as intermediaries. Lacustrine sediments are important sinks for heavy metals and play a significant role in enrichment and remobilization of heavy metals in aquatic systems. Therefore, characteristics of heavy metal in lacustrine sediments become one of the important issues in environmental sciences. Progress in heavy metal research of lake sediments since late 1980s is reviewed comprehensively in this paper from over 100. The Highlights are placed on the establishment of aquatic sediment quality guidelines, references chemical speciation of heavy metals, heavy metal transport mechanisms in lakes, and high-resolution study of lake borehole cores. Meanwhile, suggestions for heavy metal research in lacustrine sediment in the future are proposed, including such issues as using integrated approaches to assess aquatic ecosystem, modem lake dynamic process, high-resolution evolutionary sequence and spatial differentiation of environments and international lake database, which should be referential to the promotion of research on heavy metal in aquatic system. 相似文献
9.
On the basis of lacustrine sedimentary profile of Ebinur Lake, sequences of evolution of paleoclimate and paleoenvironment
in Ebinur Lake area have been rebuilt by analysing the sedimentary stratigraphy, bio-stratigraphy and geochemistry as well
as the chronological records. The results show that, during the last 10 ka years, the general change trends of the paleoclimate
in E-binur Lake area can be divided into three stages: (1) 10. 2 – 8.3 ka B. P., a warm-cool dry climate stage; (2) 8.3–3.5
ka B. P., a warmer moist climate stage (specially, 7.3–6.4 ka B. P., a relatively stable humid temperate stage); (3) 3.5 ka
B. P. —present, adraught temperate climate stage, similar to the present climate. In addition, there existed clearly several
times of secondary undulations of dry-humid climate, i.e. 8.3 ka and 7.3 ka for dry climate 相似文献
10.
ＴＨＥＨＯＬＯＣＥＮＥＳＥＤＩＭＥＮＴＡＬＣＨＡＲＡＣＴＥＲＩＳＴＩＣＡＮＤＰＡＬＥＯＣＬＩＭＡＴＩＣＥＶＯＬＵＴＩＯＮＯＦＥＢＩＮＵＲＬＡＫＥ，ＸＩＮＪＩＡＮＧ吴敬禄，王苏民，吴艳宏ＴＨＥＨＯＬＯＣＥＮＥＳＥＤＩＭＥＮＴＡＬＣＨＡＲＡＣＴＥＲＩＳＴ... 相似文献
11.
准中4区块侏罗系头屯河组滩坝及风暴沉积特征 总被引：1，自引：1，他引：0
在准噶尔盆地中部(简称准中)4区块侏罗系岩心观察的基础上,考虑粒度分析、薄片镜下观察及古气候恢复成果,认为该区头屯河组沉积时期发育滨浅湖滩坝沉积;以典型风暴沉积构造的识别为基础,提出一种与滩坝相伴生出现的新的风暴岩类型——滨浅湖风暴岩,并建立理想垂向序列模型,自下至上依次为:递变、块状层段(Sa),平行层段、冲洗交错层段(Sb),波状层段(Sc);断续纹层段(Sd)和滨浅湖泥岩段(Se).该类风暴岩发育在正常浪基面之上的滨浅湖地区,与半深湖风暴岩相比,更易遭受后期波浪改造而难以完整保存;因其发育的平面位置不同,滨浅湖风暴岩序列顶底的沉积物可以是氧化色调的滨浅湖泥坪沉积物或是正常的滨浅湖滩坝沉积物.滨浅湖风暴岩的提出完善了滨浅湖滩坝沉积体系,为研究区古地理、古气候特征的恢复提供线索,为滩坝的成因和沉积环境研究提供思路,对准噶尔盆地隐蔽油气藏的勘探具有一定指导意义. 相似文献
12.
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
13.
Minghui Li Shichang Kang Liping Zhu Feiyue Wang Junbo Wang Chaolu Yi Xiaomin Fang Manping Xie 《山地科学学报》2009,6(4):346-353
In lacustrine sediments, aragonite is a widespread mineral, whereas monohydrocalcite is a rare carbonate mineral. In the cold and high-attitude Xizang （Tibetan） Plateau, where aragonite has been commonly found in lacustrine sediments, there is no aragonite, but low-Mg calcite, monohydrocalcite and trace dolomite. The lake receives solutes primarily from surface runoffs and remains fairly constant water chemistry for a long time. The total CaCO3 percentage in sediments could be controlled by evaporation and inflow of detrital materials. The absence of aragonite is unusual when compared to other lacustrine sediments from the Tibetan Plateau. This could be due to low Ca/Mg ratio, low salinity, low Mg and Ca concentration. Monohydrocalcite might precipitate from the lake water mediated by biological activities. Low-Mg calcite originated from minor ostracoda shell and the precipitation of lake water with biological activities. 相似文献
14.
The sulfate-reducing bacteria (SRB) community in the deep-sea sediments of the west Pacific Warm Pool (WP) was surveyed by molecular phylogenetic analyses using primers targeting the 16S rRNA gene fragments of SRB. Specific 16S rRNA gene libraries from five sediment layers (1-cm, 3-cm, 6-cm, 10-cm and 12-cm layer) of the 12-cm core of WP-0 were constructed. The clones in the five libraries were differentiated by restriction fragment length polymorphism (RFLP) and representative clones were selected to sequence. It was found that the clones fell into four groups, which were closest related to Desulfotomaculum, Desul- facinum, Desulfomonile and Desulfanuticus. Desulfacinum-like clones were only detected in the upper layers of the sediment core, whereas Desulfomonile-like clones were only present in the deeper layers. Fluorescence in situ hybridization (FISH) was further carried out to visualize and count the SRB and bacteria in the five sediment layers. It was found that SRB constituted only a small proportion of the bacteria community (0.34%-1.95%), it had the highest content in the 3-cm layer (1.95%) and had a depth- related decreasing tendency along the 12- cm core. 相似文献
15.
基于仙女山-九畹溪断裂带附近地区地质构造,讨论三峡水库蓄水前后该断裂带附近地区的地震活动特征,同时分析该区域2014-03 M4.5与M4.7地震间的触发关系及2次地震对后续小震的影响。结果表明：1）M4.7地震可能由M4.5地震与库水渗流产生的较大孔隙压力共同触发。2）M4.5与M4.7两次地震的应力扰动导致研究区内地震活动增加,后续地震中约66.9%的地震发生于库仑应力增强区。3）2次地震产生的静态库仑应力变化导致仙女山断裂带附近地区地震活动增加,后续地震活动水平将处于背景地震活动水平之上;九畹溪断裂带活动性相对较弱,略小于背景地震活动水平,且处于应力积累阶段。 相似文献
16.
本文利用高频深源近震地震波形数据的R/Z比来获取沉积盆地速度结构,并以2011-05-10发生在黑龙江省与吉林省交界处(131.09°E,43.32°N)的M W5.7深源地震(深度554.9 km)为例,分析位于松辽盆地沉积层内部NECESSArray中的22个台站记录到的0.5~2 Hz数据,利用沉积盆地对地震波的到时延迟效应及P波和Ps转换波的振幅信息,通过对沉积盆地底部剪切波速度与厚度进行网格搜索获得松辽盆地的速度结构。结果显示,22个台站下方的沉积层顶部剪切波速度为0.1~1.0 km/s,且盆地边缘速度较大,盆地厚度为0~6.5 km,总体呈现内部大于边缘的状态。与已有结果相比,本文结果在沉积层边缘地带较符合实际趋势,表明利用高频近震深源Ps转换波的方法可以较好地获得沉积盆地内部的速度结构。 相似文献
17.
基于雷达干涉测量技术,利用ALOS-2、Sentinel-1卫星升降轨雷达影像,获得2019-10~12发生在菲律宾棉兰老岛的4次MW>6.0地震的同震形变场,并以此形变结果为约束,反演得到4次地震的断层运动模型。综合分析发现,此次地震序列由3条断裂的破裂引起,其中2019-10-16和2019-10-31的2次地震为同一发震断裂,2019-10-31地震断层破裂区域位于2019-10-16地震断层破裂的东北延伸段,最大滑动量约为1.1 m,约为2019-10-16地震最大滑动量的2倍。2019-10-29地震由一条独立断层破裂引起,断层最大滑动量约为2.0 m。2019-12-15地震由一条东北向倾斜断层破裂引起,断层最大滑动量约为3.0 m。此外,2019-10-16地震引起2019-10-29地震显著滑动区明显的正向库仑应力传输;而2019-10-29地震显著增加了2019-10-31地震震源区域的库仑应力;前3次地震对2019-12-15地震孕震断层的库仑应力传输总和为负值,说明静态库仑应力传输可能不是此次地震触发的主要诱因。 相似文献
18.
2006年 9月17～22日在秭归泄滩镇西侧发生了一次极微震群活动,其中最大地震为9月20日21时10分 ML1.8级.分析结果表明:本次震群的震中主要集中于泄滩镇老石门村至老泄滩一线,震源深度为海平面以上0.5 km范围内,为正倾滑机制解;该震群频谱最佳频率主要集中在2 Hz左右,初步推断该震群为地表层重力作用下矿塌型地震并伴有几次浅层微滑坡. 相似文献
19.
During CHINARE-15(Dec. 1998 - Mar. 1999), a lake core 67. 5 cm in length, was sampled in Y2 lake, which is located on the Ardley Island, Antarctica.The concentrations of some chemical elements in Y2 lake sediments were analyzed.According to comparative research on elementary characters of sediments in Antarctic West Lake, fresh penguin dropping as well as guano soil on the Ardley Island and Pacific Island in South China Sea, it presents that the Y2 lake sediments were ameliorated by penguin dropping. The result of element cluster analysis shows that the type elements in the sediment impacted by penguin dropping include Sr, F, S,P,Ca,Se,Cu, Zn and Ba. This can provide a base for further interpreting the climatic and environmental event recorded in the sediment. 相似文献
20.
ＡＮＮＵＡＬ ＬＡＭＩＮＡＴＩＯＮＳ ＩＮ ＴＨＥ ＳＥＤＩＭＥＮＴＳ ＯＦ ＨＯＮＧＦＥＮＧ ＬＡＫＥ， ＣＨＩＮＡＡＮＮＵＡＬＬＡＭＩＮＡＴＩＯＮＳＩＮＴＨＥＳＥＤＩＭＥＮＴＳＯＦＨＯＮＧＦＥＮＧＬＡＫＥ，ＣＨＩＮＡ￥ＷｕＦｅｎｇｃｈａｎｇ；Ｗａ... 相似文献