期刊文献+

二次检索

题名
关键词
文摘
作者
第一作者
机构
刊名
分类号
参考文献
作者简介
基金资助
栏目信息

年份

期刊收录

作者

共找到175篇文章
< 1 2 9 >
每页显示 20 50 100
Chronological Link Between the Abrupt Change of the Loess Grain Size Sequence and the Formation of River Terraces on the Eastern Margin of the Qinghai-Tibetan Plateau Since the Late Early-Pleistocene 被引量:4
1
作者 LIU Dongyan QIAO Yansong +2 位作者 LI Weiran XIE Ruihuang PENG Shasha 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2011年第3期723-732,共10页
Based on the study of magnetostratigraphy,magnetic susceptibility and grain size of Garze A section on the southeastern margin of the Qinghai-Tibetan Plateau since the late early-Pleistocene,the basal age of Garze loe... Based on the study of magnetostratigraphy,magnetic susceptibility and grain size of Garze A section on the southeastern margin of the Qinghai-Tibetan Plateau since the late early-Pleistocene,the basal age of Garze loess is located at~1.16 MaBP and a series of abrupt paleoclimatic changes is detected.The times of abrupt changes are of distinct series features,and the interval between each two adjacent abrupt changes is~50 kyr or~100 kyr.The most significant abrupt changes occur at around 1.06,0.85,0.6,0.46,0.39 and 0.14 MaBP.There is a chronological link between the abrupt changes of paleoclimate and the formation of river terraces and it is almost simultaneous with a strengthening trend of neotectonic activities.Therefore,maybe the climatic transition controll the timing of terrace formation,and the tectonic uplift originate potential energy and has a direct effect on channel incision, both the climatic transition and the tectonic uplift are important.Terraces are the products of the interaction of instable climatic variations and tectonic uplift.Like the loess-paleosol sequences,river terrace sequences are also controlled by the climate-tectonic coupling system and are ruled by climate-tectonic gyration with a~100 kyr paracycle,which may be the short eccentricity period of the earth. 展开更多
关键词 Garze loess grain size TERRACE tectonic uplift the Qinghai-Tibetan Plateau
下载PDF
Mastersize 2000型激光粒度仪分析数据可靠性检验及意义——以洛川剖面S4层古土壤为例 被引量:44
2
作者 雷国良 张虎才 +6 位作者 张文翔 牛洁 杨明生 陈玥 樊红芳 常凤琴 李斌 《沉积学报》 CAS CSCD 北大核心 2006年第4期531-539,共9页
黄土、古土壤剖面中物质粒度是恢复古环境的重要指标之一。精确地测定粒径的大小,是准确而可靠获取气候变化信息的基本前提。通过对洛川典型黄土剖面古土壤S 4及相临黄土层高密度、连续样品多次重复粒度测试结果经统计分析表明:粒径测... 黄土、古土壤剖面中物质粒度是恢复古环境的重要指标之一。精确地测定粒径的大小,是准确而可靠获取气候变化信息的基本前提。通过对洛川典型黄土剖面古土壤S 4及相临黄土层高密度、连续样品多次重复粒度测试结果经统计分析表明:粒径测量的误差主要来自于两方面,即仪器测量与前处理过程,其中前处理过程的影响是粒度测量中误差的主要来源。同时证明,单次测量结果具有不确定性,因此可靠的粒度参数需经多次测量平均获得。但是,此过程会导致某些快速变化信息的丢失和因峰态的平滑而造成粒度变化所反映的变化幅度弱化。 展开更多
关键词 洛川黄土剖面 S4 粒度分析 面积差异 测量误差
下载PDF
Mangshan Loess in Central China and the Paleomonsoon Variations since the Last Interglaciation 被引量:6
3
作者 JIANGFuchu WANGShubing ZHAOZhizhong FUJianli 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第3期813-819,共7页
The Mangshan Yuan is a loess platform on the southern bank of the Yellow River, which is located in northwestern Zhengzhou of Henan Province, China. The typical Zhaoxiayu section of the Mangshan Yuan preserves stratig... The Mangshan Yuan is a loess platform on the southern bank of the Yellow River, which is located in northwestern Zhengzhou of Henan Province, China. The typical Zhaoxiayu section of the Mangshan Yuan preserves stratigraphical loess units above S10 with a total thickness of 172.1 m, which includes 15.7 m of the last interglacial paleosol S1, 77.3 m of the last glacial loess L1 that consist of 41.6 m of the late stade L1LL1, 13.2 m of the interstade L1SS1 and 22.5 m of the early stade L1LL2. Based on the age marking points by correlating magnetic susceptibility of the section with the SPECMAP curve, the timescale of the section was constructed, and the average accumulation rate and the resolution of each loess strata over the S2 were subsequently calculated using the susceptibility age model. The results indicate that strata units developed in the glacial, interglacial stages, stadial and interstadial show substantial differences in grain size, average accumulation rate and time resolution ub the Zhaoxiayu section. Specifically, the average accumulation rate of the loess L1LL1 is 3.45 mm/a, whereas that of paleosol S1 is only 0.28 mm/a. Based on the high-resolution records of magnetic susceptibility and >45μm fraction percentage of the loess-paleosol, the summer and winter monsoon variations as well as their interrelations since the last interglaciation have been discussed, which were correlated with the SPECMAP and the GRIP climate records. 展开更多
关键词 loess magnetic susceptibility grain size PALEOMONSOON Mangshan Henan Province
下载PDF
Paleoenvironmental Record from Wuqi Paleolake in Northern Chinese Loess Plateau
4
作者 GUO Jiao WANG Wei +2 位作者 WU Lijie CHEN Hongyun DONG Qiuyao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期8-9,共2页
Jinding core(ZK04,36°47′35.36″N,108°19′05.24″E)is located in the northern area of Luohe river basin,northern Chinese loess plateau,lying to the southeast of Wuqi County about 20 km.The total depth of Cor... Jinding core(ZK04,36°47′35.36″N,108°19′05.24″E)is located in the northern area of Luohe river basin,northern Chinese loess plateau,lying to the southeast of Wuqi County about 20 km.The total depth of Core ZK04 is 92.20 展开更多
关键词 Wuqi paleolake magnetic susceptibility grain size paleomagnetic chronology PALEOENVIRONMENT Chinese loess Plateau
下载PDF
Influences of sand cover on erosion processes of loess slopes based on rainfall simulation experiments 被引量:7
5
作者 ZHANG Xiang LI Zhanbin +3 位作者 LI Peng TANG Shanshan WANG Tian ZHANG Hui 《Journal of Arid Land》 SCIE CSCD 2018年第1期39-52,共14页
Aeolian-fluvial interplay erosion regions are subject to intense soil erosion and are of particular concern in loess areas of northwestern China. Understanding the composition, distribution, and transport processes of... Aeolian-fluvial interplay erosion regions are subject to intense soil erosion and are of particular concern in loess areas of northwestern China. Understanding the composition, distribution, and transport processes of eroded sediments in these regions is of considerable scientific significance for controlling soil erosion. In this study, based on laboratory rainfall simulation experiments, we analyzed rainfall-induced erosion processes on sand-covered loess slopes (SS) with different sand cover patterns (including length and thickness) and uncovered loess slopes (LS) to investigate the influences of sand cover on erosion processes of loess slopes in case regions of aeolian-fluvial erosion. The grain-size curves of eroded sediments were fitted using the Weibull function. Compositions of eroded sediments under different sand cover patterns and rainfall intensities were analyzed to explore sediment transport modes of SS. The influences of sand cover amount and pattern on erosion processes of loess slopes were also discussed. The results show that sand cover on loess slopes influences the proportion of loess erosion and that the compositions of eroded sediments vary between SS and LS. Sand cover on loess slopes transforms silt erosion into sand erosion by reducing splash erosion and changing the rainfall-induced erosion processes. The percentage of eroded sand from SS in the early stage of runoff and sediment generation is always higher than that in the late stage. Sand cover on loess slopes aggravates loess erosion, not only by adding sand as additional eroded sediments but also by increasing the amount of eroded loess, compared with the loess slopes without sand cover. The influence of sand cover pattern on runoff yield and the amount of eroded sediments is larger than that of sand cover amount. Furthermore, given the same sand cover pattern, a thicker sand cover could increase sand erosion while a thinner sand cover could aggravate loess erosion. This difference explains the existence of intense erosion on slopes that are thinly covered with sand in regions where aeolian erosion and fluvial erosion interact. 展开更多
关键词 aeolian-fluvial erosion sand-covered loess slopes sand cover amount sand cover pattern rainfall intensity grain-size distribution Inner Mongolia Reach of the Yellow River
下载PDF
阿坝盆地黄土记录的青藏高原东部末次冰期环境变化
6
作者 徐雪超 刘丽 +4 位作者 杨胜利 问琛 李睿 张景钊 王海燕 《海洋地质与第四纪地质》 CAS CSCD 北大核心 2024年第4期168-179,共12页
青藏高原东部广泛分布的风成黄土沉积是记录过去气候变化和大气粉尘活动历史的重要陆地档案,恢复和重建其环境记录可以为深入理解高原环境演化过程和机制提供重要证据。本研究基于石英光释光测年建立了阿坝盆地各莫黄土剖面的年代框架,... 青藏高原东部广泛分布的风成黄土沉积是记录过去气候变化和大气粉尘活动历史的重要陆地档案,恢复和重建其环境记录可以为深入理解高原环境演化过程和机制提供重要证据。本研究基于石英光释光测年建立了阿坝盆地各莫黄土剖面的年代框架,并利用多种环境代用指标重建了阿坝黄土记录的青藏高原东部约47 ka以来的环境变化历史。黄土磁化率、色度和碳酸盐记录表明深海氧同位素3阶段(MIS3)中晚期印度夏季风加强,青藏高原环境相对湿润。粒度重建结果记录了4次海因里希(Heinrich)事件和新仙女木(YD)事件,表明青藏高原末次冰期粉尘活动强烈,气候变化具有快速波动的特征。区域记录对比显示,北半球高纬地区气候系统对青藏高原地区快速气候变化有重要影响,大西洋经向翻转环流可能是高原地区粉尘活动和气候变化的主要控制因素。该研究为更好地认识青藏高原末次冰期环境演化过程提供了重要证据。 展开更多
关键词 黄土 光释光测年 粒度 磁化率 末次冰期
下载PDF
淮河支流汝河全新世古洪水沉积序列粒度指示的地表过程 被引量:1
7
作者 王兆夺 黄春长 +4 位作者 周亚利 陈莹璐 尚瑞清 查小春 庞奖励 《沉积学报》 CAS CSCD 北大核心 2024年第4期1268-1278,共11页
【目的和方法】为了深入理解淮河流域全新世环境与地表过程演变,通过对淮河流域详细的野外调查,在汝河上游诸市乡段一级河流阶地前沿发现了夹有多层古洪水滞流沉积层的全新世黄土土壤沉积物地层剖面。对该剖面进行详细观察测量,地层划... 【目的和方法】为了深入理解淮河流域全新世环境与地表过程演变,通过对淮河流域详细的野外调查,在汝河上游诸市乡段一级河流阶地前沿发现了夹有多层古洪水滞流沉积层的全新世黄土土壤沉积物地层剖面。对该剖面进行详细观察测量,地层划分和分层采样,在实验室进行多种指标分析研究。在前期沉积学性质研究和年代测定的基础上,应用端元分析方法进行粒度成分解析,深入分析古洪水沉积物序列的物源及其沉积学特征变化规律。【结果】采用非参数法从沉积序列中解析出具有不同物源和沉积动力学意义的4个端元组分。各土壤沉积物地层单元中除了现代洪水沉积层和河漫滩相细沙层外,其余层次都显示出多端元组分混合叠加的特点。【结论】结合野外宏观特征及其理化性质综合分析,可知其端元1组分代表西北季风沙尘暴远源风成沉积物及其风化成壤改造的产物,端元2组分代表了东北风吹扬黄泛平原松散沉积物沙尘暴的近源沉积物,端元3组分代表了河流洪水悬移质泥沙在高水位滞流环境条件下的沉积物,端元4组分为河流在河槽之内水动力作用下河漫滩冲积物。表明通过对全样粒度进行端元解析,能够更清晰地反映出汝河流域多元化的沉积动力特点。 展开更多
关键词 黄土 古土壤 古洪水 粒度端元分析 全新世 淮河
下载PDF
Paleoclimatic significance of grain size of loess-palaeosol deposit in Chinese Loess Plateau 被引量:50
8
作者 鹿化煜 安芷生 《Science China Earth Sciences》 SCIE EI CAS 1998年第6期626-631,共6页
Particle size analysis for samples from three last glacial cycle loess-palaeosol profiles along a northwestsoutheast transection on the Chinese Loess Plateau has been carried out. The paleoclimatic significance of gra... Particle size analysis for samples from three last glacial cycle loess-palaeosol profiles along a northwestsoutheast transection on the Chinese Loess Plateau has been carried out. The paleoclimatic significance of grain size indices has been obtained by analyzing the fraction content variations and their comparisons with global ice volume and solar radiation variations. The results show that (i) paleoclimatic significance of the grain size indices of loess-palaeosol deposit is different with grain size fraction content and sampling points in Chinese Loess Plateau; (ii) the sub-coarse grain fraction is a good proxy index of East Asia winter monsoon strength and therefore can be used to detect the global climate changes; (iii) the content of sub-fine and fine grain fractions is influenced by both the input of sub-coarse grain fraction and pedogenesis; (iv) the sub-coarse fraction exhibits a negative relationship with the sub-fine and fine fractlon. 展开更多
关键词 PALEOCLIMATIC significance loess_palaeosol grain size Chinese loess Plateau.
原文传递
Grain-size features of a Miocene loess-soil sequence at Qinan: Implications on its origin 被引量:36
9
作者 QIAO Yansong1,3, GUO Zhengtang2,1, HAO Qingzhen1, YIN Qiuzhen1, YUAN Baoyin1 & LIU Tungsheng1 1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 2. Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075, China 3. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China 《Science China Earth Sciences》 SCIE EI CAS 2006年第7期731-738,共8页
In this study, grain-size of 507 bulk samples from the QA-I Mioceneloess-soil sequence at Qinan were analyzed, and the grain-size features are compared with those oftypical Quaternary loess and soil samples, represent... In this study, grain-size of 507 bulk samples from the QA-I Mioceneloess-soil sequence at Qinan were analyzed, and the grain-size features are compared with those oftypical Quaternary loess and soil samples, representative lacustrine and fluvial samples. Theresults indicate that the grain-size distribution pattern of the Miocene loess is essentiallysimilar to that of Quaternary loess, but greatly differs from the lacustrine and fluvial sediments.Loess layers are regularly coarser than soil layers, indicating cyclical climate changes. Mediangrain-size along the 253.1 m sequence varies from 6 to 13 μm and the 】 63 μm fraction representsonly 5.3% in maximum, 0.9% in average. Long-term grain-size variations are consistent with the loessaccumulation rate at Qinan and with the eolian mass accumulation rate in the North Pacific. Thesefeatures firmly indicate an eolian origin of the studied sequence, and also reveal a coeval changesbetween the long-term changes of eolian grain-size and continental aridity in the dust sourceregions. 展开更多
关键词 Qinan MIOCENE loess-soil sequence grain-size EOLIAN origin.
原文传递
Grain size distribution of quartz isolated from Chinese loess/ paleosol 被引量:9
10
作者 SUN Youbin LU Huayu AN Zhisheng 《Chinese Science Bulletin》 SCIE EI CAS 2000年第24期2296-2298,共3页
Grain size distribution of bulk loess-paleosol and quartz chemically extracted from the loess/paleosol shows that mean size of the bulk samples is always finer than that of the quartz. The original aeolian depositions... Grain size distribution of bulk loess-paleosol and quartz chemically extracted from the loess/paleosol shows that mean size of the bulk samples is always finer than that of the quartz. The original aeolian depositions have been modified to various degrees by post-depositional weathering and pedogenic processes. The grain size distribution of the isolated quartz should be close to that of the primary aeolian sediment because the chemical pretreatment excludes secondary produced minerals. Therefore, the grain size of the quartz may be considered to more clearly reflect the variations of winter monsoon intensity. 展开更多
关键词 loess/paleosol QUARTZ grain size distribution.
原文传递
Comparisons of grain size characteristics of red earth from southern China with that of loess and dune sand from Beijing region 被引量:3
11
作者 Xiong, SF Ding, ZL Liu, DS 《Chinese Science Bulletin》 SCIE EI CAS 1999年第18期1690-1693,共4页
The comparisons of grain size distributions among eolian deposits along the monsoon wind trajectory are a fundamental task for the reconstruction of the past wind regimes. Here the authors sampled the dune sands in Hu... The comparisons of grain size distributions among eolian deposits along the monsoon wind trajectory are a fundamental task for the reconstruction of the past wind regimes. Here the authors sampled the dune sands in Hunsandak desert, loess deposits in Beijing region and red earth in southern China. Grain size analyses show that the distribution models of the loess 展开更多
关键词 RED EARTH loess DUNE SAND grain size.
原文传递
Geochemistry of 0.7 Ma B.P. Microtektite- bearing Loess Layers——Ⅲ Grain Size Distribution
12
作者 李春来 林文祝 欧阳自远 《Chinese Science Bulletin》 SCIE EI CAS 1994年第24期2049-2052,共4页
The features of grain size distribution of microtektite-bearing layers are crucial, direct indicators to reflect the addition of impact dust into loess sediments.Because their sampling intervals were too large, previo... The features of grain size distribution of microtektite-bearing layers are crucial, direct indicators to reflect the addition of impact dust into loess sediments.Because their sampling intervals were too large, previous surveys could not reveal the contamination of the loess sediments by impact fallout (dust) in light of grain size distribution. Here, the authors present measurements for grain size distribution of loess samples taken around the microtektite-bearing layers at very dense sampling intervals. 展开更多
关键词 loess microtektite impact EVENT grain size.
原文传递
中国黄土粒度的双峰分布及其古气候意义 被引量:229
13
作者 孙东怀 鹿化煜 +2 位作者 David Rea 孙有斌 吴胜光 《沉积学报》 CAS CSCD 北大核心 2000年第3期327-335,共9页
中国黄土的粒度分布由分布峰度较高、分选较好的粗粒组分和分布峰度较低、分选较差的细粒组分叠加组成 ;前者代表了冬季风盛行季节近距离低空搬运的粉尘物质 ,其粒度指示了东亚冬季风所主导的近地面气流的强度 ,它在全样中的含量可能反... 中国黄土的粒度分布由分布峰度较高、分选较好的粗粒组分和分布峰度较低、分选较差的细粒组分叠加组成 ;前者代表了冬季风盛行季节近距离低空搬运的粉尘物质 ,其粒度指示了东亚冬季风所主导的近地面气流的强度 ,它在全样中的含量可能反映了冬季风粉尘的沉积通量 ;细粒组分可能主要为常态存在的、由高空气流搬运的远源粉尘 ,代表了黄土高原原始粉尘的本底 ,它的粒度特征与北太平洋西风带粉尘基本一致 ,可能指示了主要由西风带控制的高空气流的强度。黄土的粒度分布函数可用代表这两个组分分布的两个WEIBULL函数的和函数表示。用实测粒度分布数据对分布函数进行拟合可计算出该分布函数的各参数 。 展开更多
关键词 黄土 粒度分布 冬季风 西风带
下载PDF
粒度分析在中国第四纪黄土古气候研究中的应用现状 被引量:38
14
作者 刘冬雁 李巍然 +1 位作者 彭莎莎 王玲 《中国海洋大学学报(自然科学版)》 CAS CSCD 北大核心 2010年第2期79-84,共6页
中国黄土是记录第四纪古气候信息的重要载体,作者就第四纪黄土研究中涉及的粒度测量、常用粒度指标、敏感粒度、粒度年龄模型以及粒度指标时间序列周期分析等方面的应用现状作了回顾。前人研究结果表明:不同前处理方法对粒度测量结果有... 中国黄土是记录第四纪古气候信息的重要载体,作者就第四纪黄土研究中涉及的粒度测量、常用粒度指标、敏感粒度、粒度年龄模型以及粒度指标时间序列周期分析等方面的应用现状作了回顾。前人研究结果表明:不同前处理方法对粒度测量结果有较大影响;传统粒度指标应用广泛;敏感粒度的确定是反演古环境的关键;粒度指标时序谱分析是古气候定量化研究的重要方法之一;粒度年龄模型仍是较可信的建立地层年代序列的方法。 展开更多
关键词 第四纪 黄土 粒度 古气候
下载PDF
鲁中黄土粒度特征及其成因探讨 被引量:28
15
作者 刘乐军 李培英 王永吉 《海洋地质与第四纪地质》 CAS CSCD 北大核心 2000年第1期81-86,共6页
鲁中黄土是风成的 ,主要由低空地方风系 (北向风 )搬运的近源物质堆积而成 ,其次是高空气流携带而来的内陆远源物质 ;主要物源区为冰期裸露的莱州湾海底和黄泛平原。粗颗粒含量变化曲线较好地反映本区气候的冷暖周期变化。中更新世中后... 鲁中黄土是风成的 ,主要由低空地方风系 (北向风 )搬运的近源物质堆积而成 ,其次是高空气流携带而来的内陆远源物质 ;主要物源区为冰期裸露的莱州湾海底和黄泛平原。粗颗粒含量变化曲线较好地反映本区气候的冷暖周期变化。中更新世中后期本区开始转冷 ,发育离石黄土 ;末次间冰期时 ,气候温湿形成厚层 S1 ;到末次冰期气候变得更为干冷 ,冬季风效应增强 ,粗颗粒含量增多。到全新世气候向现代气候转变 ,但在转暖的过程中有短期回冷事件 ,形成全新世黄土。 展开更多
关键词 鲁中黄土 粒度 成因机制 沉积环境 黄土 古气候
下载PDF
天水黄土沉积特征与环境变化 被引量:12
16
作者 刘小丰 潘保田 +4 位作者 高红山 王勇 王均平 张慧 胡春生 《中国沙漠》 CSCD 北大核心 2007年第3期373-378,共6页
中滩剖面系中滩镇渭河第四级阶地上的黄土堆积,通过黄土剖面的地层结构及粒度分析表明,其形成于0.9 Ma以来,河漫滩堆积年代为0.86—0.94 Ma。在过去1 Ma以来,中滩黄土及河漫滩剖面的地层特征、粒度曲线表明其记录了9个湿热干冷气候旋回,... 中滩剖面系中滩镇渭河第四级阶地上的黄土堆积,通过黄土剖面的地层结构及粒度分析表明,其形成于0.9 Ma以来,河漫滩堆积年代为0.86—0.94 Ma。在过去1 Ma以来,中滩黄土及河漫滩剖面的地层特征、粒度曲线表明其记录了9个湿热干冷气候旋回,3次冬季风强化阶段,存在着3次极端干旱事件。中滩黄土粒度特征以粉砂为其众数粒级,其次为粘土颗粒,不同于黄土高原其他地区,可能与秦岭北麓的湿润环境及六盘山对冬季风的阻挡有关。 展开更多
关键词 黄土 粒度曲线 黄土古土壤序列 气候旋回 1Ma 甘肃天水
下载PDF
末次间冰期以来渭河上游气候演化的黄土记录研究 被引量:11
17
作者 张慧 潘保田 +3 位作者 徐树建 管清玉 苏怀 刘小锋 《中国沙漠》 CSCD 北大核心 2007年第2期182-186,共5页
对渭河上游樊家台剖面末次间冰期以来黄土地层的粒度与CaCO3进行综合分析表明,末次间冰期时,受夏季风影响较大,粒度较细,CaCO3有较强的淋溶与淀积,气候呈现较为暖湿的特点;末次冰期时,受冬季风影响较强,粒度较粗,CaCO3淋溶淀积微弱,气... 对渭河上游樊家台剖面末次间冰期以来黄土地层的粒度与CaCO3进行综合分析表明,末次间冰期时,受夏季风影响较大,粒度较细,CaCO3有较强的淋溶与淀积,气候呈现较为暖湿的特点;末次冰期时,受冬季风影响较强,粒度较粗,CaCO3淋溶淀积微弱,气候较为干冷。间冰期早期(相当于深海氧同位5e阶段)由于夏季风较强,粉尘堆积较少,古土壤向下发育,并与下部土壤融合,导致粒度较5a、5c阶段粗;2阶段的早期,由于粉尘源区出现了高湖面,环境湿度大,造成此时段早期黄土粒度较晚期细;表现出区域气候的特点。 展开更多
关键词 渭河 末次间冰期 黄土 粒度 碳酸钙 气候演化
下载PDF
2006年4月17日北京特大降尘的地球化学特征 被引量:8
18
作者 张崧 刘平 +3 位作者 靳春胜 韩家懋 秦小光 刘东生 《海洋地质与第四纪地质》 CAS CSCD 北大核心 2008年第3期35-42,共8页
2006年4月17日北京遭遇了近年来最为严重的一次降尘天气。分析了降尘的主量、微量和稀土元素地球化学特征,并与洛川马兰黄土和几次北京降尘进行对比,结果显示本次北京降尘与洛川马兰黄土具有相似的元素分布模式,表明与黄土具有相似的物... 2006年4月17日北京遭遇了近年来最为严重的一次降尘天气。分析了降尘的主量、微量和稀土元素地球化学特征,并与洛川马兰黄土和几次北京降尘进行对比,结果显示本次北京降尘与洛川马兰黄土具有相似的元素分布模式,表明与黄土具有相似的物质组成,并在搬运过程中经历了充分的混合,同时,北京降尘与黄土相比具有一定程度的差异性,表现为北京降尘中Mg、Na相时富集,Ca明显亏损并含有较高的烧失量,降尘CIA值较低,表明降尘源区化学风化程度较弱,处于化学风化的初始阶段,降尘∑REE显著高于黄土,同时轻、重稀土分馏程度也较黄土高,4次北京降尘间稀土元素分布模式对比表明,粒度是影响重稀土元素间分馏程度不同的主要因素。 展开更多
关键词 降尘 地球化学 黄土 粒度 北京
下载PDF
中亚昭苏黄土剖面粒度记录的末次冰期以来气候变化历史 被引量:26
19
作者 李传想 宋友桂 +1 位作者 千琳勃 王乐民 《沉积学报》 CAS CSCD 北大核心 2011年第6期1170-1179,共10页
对处于西风区的中亚昭苏黄土进行了粒度分析,重建了末次冰期以来的气候环境变化历史。粒度分析表明,昭苏黄土粉砂粒级含量最高,平均含量接近78%,黏土粒级次之,砂粒含量最低,具有典型的风尘堆积特征。剖面粒径>63μm含量变化能与格陵... 对处于西风区的中亚昭苏黄土进行了粒度分析,重建了末次冰期以来的气候环境变化历史。粒度分析表明,昭苏黄土粉砂粒级含量最高,平均含量接近78%,黏土粒级次之,砂粒含量最低,具有典型的风尘堆积特征。剖面粒径>63μm含量变化能与格陵兰冰芯进行良好对比,记录了Heinrich事件和Younger Dryas冷事件及D-O旋回等具有全球意义的气候波动事件,揭示中亚地区末次冰期以来的气候变化具有全球特征。 展开更多
关键词 昭苏剖面 黄土粒度 末次冰期 中亚 气候变化
下载PDF
山东青州地区黄土的粒度组成及成因分析 被引量:25
20
作者 彭淑贞 高志东 +3 位作者 吴秀平 张连兵 梁明英 乔彦松 《地质力学学报》 CSCD 2007年第4期315-321,共7页
在鲁中山地北侧的山间谷地及山麓地带广泛发育厚度不一的黄土堆积。对该区青州傅家庄黄土剖面进行了系统的粒度分析,并与黄土高原的第四纪黄土-古土壤、北京现代降尘、剖面附近的河流相样品进行了对比。结果表明,青州黄土的粒度分布特... 在鲁中山地北侧的山间谷地及山麓地带广泛发育厚度不一的黄土堆积。对该区青州傅家庄黄土剖面进行了系统的粒度分析,并与黄土高原的第四纪黄土-古土壤、北京现代降尘、剖面附近的河流相样品进行了对比。结果表明,青州黄土的粒度分布特征与北京现代降尘、黄土高原黄土非常相似,与河流相样品则有很大的不同;在整个序列中,青州黄土粒度变化与黄土高原典型的风成黄土、古土壤一致,黄土层颗粒粗,古土壤层颗粒细。上述结果从沉积学的角度为青州黄土风成成因提供了证据。青州黄土的粒度组成特征及前人的研究表明,青州黄土主要来源于沉积区以北的黄泛平原和莱州弯等地出露的海相地层,其次是高空气流携带的西北内陆的远缘粉尘。 展开更多
关键词 山东 青州 黄土-古土壤 粒度 成因
下载PDF
上一页 1 2 9 下一页 到第
使用帮助 返回顶部