武汉沿长江、汉江Cd高值带成因初探   总被引：18，自引：0，他引：18  

马振东  张德存  闭向阳  刘光强  任利民  全浩理 《地质通报》2005,24(8):740-743

在1999—2000年第一轮多目标区域地球化学调查中,湖北省地质调查院在武汉市辖区的沿江(长江、汉江)冲积成因土壤中发现了重金属元素Cd的高值带,长江和汉江冲积土中Cd含量分别为0.33×10-6和0.27×10-6。研究结果表明:①长江和汉江冲积成因土壤的化学组成有明显的差异;②两江冲积物化学组成分别受扬子陆块和秦岭造山带表壳岩系化学组成的制约;③两构造单元表壳岩系相对富Cd岩石的风化产物是两江沿江冲积成因土壤Cd高值带的主要来源之一;④沿江冲积成因土壤中Cd的富集与其表生地球化学性质有关。  相似文献   

济南张夏黄土堆积及其成因分析   总被引：1，自引：0，他引：1       下载免费PDF全文

张祖陆  辛良杰  姜鲁光  黄萍 《古地理学报》2005,7(1):98-106

鲁中南山地西北边缘的山麓地带、大沙河沿岸阶地广泛分布厚度不一的黄土堆积。其中出露在河岸阶地的济南市长清区张夏镇的黄土物质来源复杂，既有西北气流，东部渤海湾气流搬运而来的物质，又有当地生成的坡洪积碎屑物质。张夏黄土下部呈现明显的水流侵蚀痕迹，中间夹有围岩碎屑，应属于风成-洪积、坡积成因的黄土状土。  相似文献   

Bedrock lithology control on contemporaneous alluvial fan facies, Oligo-Miocene, southern Pyrenees, Spain   总被引：1，自引：0，他引：1  

GARY NICHOLS†  BEN THOMPSON 《Sedimentology》2005,52(3):571-585

Climate and tectonics play important roles in controlling processes of transport and deposition on alluvial fans, but the bedrock lithology in the fan catchment area is also a significant, independent factor. Adjacent Oligo-Miocene alluvial fan deposits on the northern margin of the Ebro Basin display contrasting depositional characteristics with one dominated by the deposits of debris flows and the other by deposition from flows of water. A difference in clast compositions indicates that the two studied fans (the Nueno and San Julián fans) had contrasting bedrock lithology in their drainage basins. The proximal facies of the Nueno fan body contains matrix-supported conglomerate beds with up to 80% pebble clasts of gypsum in a matrix of gypsiferous sand, interbedded with gypsarenite beds. The drainage basin of this fan was dominated by Triassic bedrock consisting of beds of gypsum, marl and micritic limestone. The San Julián fan body comprises clast-supported, polymict conglomerate beds containing pebbles from Triassic, Cretaceous and Palaeogene limestone units that are exposed in the adjacent part of the basin margin. The interfingering of the deposits of these two fans demonstrates that they were contemporaneous. Given the consistent climate, the differences in fan depositional processes must therefore be attributed to the contrasting bedrock lithology in their drainage basins. A drainage basin consisting mainly of marl and gypsum bedrock provided sufficient fine-grained material to generate debris flows, whereas more dilute, water-lain processes dominated where the drainage basin was largely limestone strata.  相似文献   

冲积平原区土壤中稀土元素分布模式及其示踪作用     

马生明  朱立新  王之峰  刘崇民  胡树起 《物探与化探》2006,30(2):100-103

根据科研生产工作的实际需要,借鉴稀土元素分布模式示踪物源的方法,对冲积平原景观区土壤中稀土元素的分布模式进行了系统研究。结果发现冲积平原区土壤中稀土元素分布模式总体规律大同小异,表明冲积平原区成壤母质特性基本相同。利用稀土元素分布模式的细微差异能够有效判别成壤母质特性的变化。  相似文献   

长--平陆相红色盆地北东段量化沉积学特征及其演化   总被引：1，自引：0，他引：1  

章泽军 《沉积学报》1998,16(4):55-61

长－平陆相红色盆地北东段（系指赣西北红层分布区）由三期5个冲积扇体组成。非同期扇体分别由特定界面所分隔。山口位于盆地北侧,古流向由北向南、南东或南西呈扇形撒开;最大砾石平均体积及混杂系数在扇根处为最大值,向扇中、扇缘呈非线性递减;砾石成分严格受物源区的制约。根据量化沉积学特征及成生背景分析,该区大致经历了初始孕育期、分段剥蚀充填期及后期构造改造三大演化阶段。洪积事件始于晚白垩世、止于早第三纪始新世-渐新世。  相似文献   

硅肥在黄河冲积土上的水稻肥效试验研究   总被引：4，自引：1，他引：3  

蔡德龙  钱发军  邓挺  孙启文 《地域研究与开发》1998,17(1):62-64

试验研究结果表明：无论以炼铁水淬渣还是以赤泥为基料生产的硅肥,在河南省黄河冲积平原水稻上施用均获得１５％以上的增产效果,尤以赤泥的基本原料生产的硅肥增产效果最佳。  相似文献   

Complex exposure histories of chert clasts in the late Pleistocene shorelines of Lake Lisan,southern Israel     

Ari Matmon  Onn Crouvi  Yehouda Enzel  Paul Bierman  Jennifer Larsen  Naomi Porat  Rivka Amit  Marc Caffee 《地球表面变化过程与地形》2003,28(5):493-506

Activities of ²⁶Al and ¹⁰Be in five chert clasts sampled from two beach ridges of late Pleistocene Lake Lisan, precursor of the Dead Sea in southern Israel, indicate low rates of chert bedrock erosion and complex exposure, burial, and by inference, transport histories. The chert clasts were derived from the Senonian Mishash Formation, a chert‐bearing chalk, which is widely exposed in the Nahal Zin drainage basin, the drainage system that supplied most of the material to the beach ridges. Simple exposure ages, assuming only exposure at the beach ridge sampling sites, range from 35 to 354 ky; using the ratio ²⁶Al/¹⁰Be, total clast histories range from 0·46 to 4·3 My, unrelated to the clasts' current position and exposure period on the late Pleistocene beach ridges, 160–177 m below sea level. Optically stimulated luminescence dating of fine sediments from the same and nearby beach ridges yielded ages of 20·0 ± 1·4 ka and 36·1 ± 3·3 ka. These ages are supported by the degree of soil development on the beach ridges and correspond well with previously determined ages of Lake Lisan, which suggest that the lake reached its highest stand around 27 000 cal. years BP . If the clasts were exposed only once and than buried beyond the range of significant cosmogenic nuclide production, then the minimum initial exposure and the total burial times before delivery to the beach ridge are in the ranges 50–1300 ky and 390–3130 ky respectively. Alternatively, the initial cosmogenic dosing could have occurred during steady erosion of the source bedrock. Back calculating such rates of rock erosion suggests values between 0·4 and 12 m My^?1. The relatively long burial periods indicate extended sediment storage as colluvium on slopes and/or as alluvial deposits in river terraces. Some clasts may have been stored for long periods in abandoned Pliocene and early Pleistocene routes of Nahal Zin to the Mediterranean before being transported again back into the Nahal Zin drainage system and washed on to the shores of Lake Lisan during the late Pleistocene. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

晚新生代天山隆升与库车坳陷构造转换的沉积约束   总被引：31，自引：2，他引：31  

李忠  王清晨  王道轩  林伟 《沉积学报》2003,21(1):38-45

对库车坳陷库车河剖面不同尺度沉积碎屑组分的系统分析发现 ,晚第三纪以来类磨拉石及其中不稳定碎屑矿物组合开始发育 ,并在中新世后发生显著增加。沉积体系研究表明 ,库车坳陷自白垩纪以来粗粒冲积体系前锋、沉积中心逐步向南迁移 ;但该规律自上新世开始发生了明显转变 ,表现为上新世库车组、上 -更新世西域组冲积体系整体大尺度南移 ,而沉积中心则相对北移 ,盆地北部沉积边界与现存盆山边界大致可以对比 ,并受到南倾同沉积正断裂的控制。对比天山区域构造、古气候演变资料 ,认为上述沉积记录是晚新生代强烈挤压应力作用下天山构造隆升加剧 ,并在上新世以后由于重力作用诱发库车坳陷 -天山浅部构造层伸展、坍塌的结果。对这一构造转换的认识修订了库车坳陷新生代构造调整的序列。  相似文献   

Distribution and land use characteristics of alluvial fans in the Lhasa River Basin,Tibet   总被引：1，自引：0，他引：1  

CHEN Tongde  JIAO Juying  CHEN Yixian  LIN Hong  WANG Haolin  BAI Leichao 《地理学报(英文版)》2021,31(10):1437-1452

In Lhasa River Basin (LRB),land suitable for settlement or living is experiencing a shortage of resources.Alluvial fans have the potential to alleviate this problem.However,basic information,such as the distribution and land use types of alluvial fans,is rarely studied.In this study,Google Earth,ArcGIS and visual interpretation were used to obtain the outlines,areas,quantities and distribution of alluvial fans.Meanwhile,to show the utilisation potential of alluvial fans,we analysed the land use,their distance from the roads,places (town and village) and rivers.The results showed 826 alluvial fans exist in LRB,with a total area of 1166.03 km2.The number of alluvial fans with areas between 0.1 and 1 km2 is 517,ac-counting for 62.59％ of the total number of alluvial fans.Grassland is the dominant land use type,accounting for 68.70％ of the total area of alluvial fans.The cropland area accounted for 2.16％ of alluvial fans and accounted for 18.98％ of the total cropland area in LRB.Exactly 93.70％,53.63％ and 61.86％ of the total number of alluvial fans were located within 5 km from the tertiary road,village,and river,respectively.To sum up,our survey results showed that alluvial fans are important land resources in LRB and may have huge utilisation potential.  相似文献   

流域上游基岩与下游冲积平原土壤化学组成的对比   总被引：2，自引：0，他引：2  

迟清华  马生明 《地质通报》2008,27(2):188-195

对海河水系流域、鄱阳湖水系流域上游的基岩与下游的冲积平原土壤之间化学组成的对比研究显示,下游冲积物土壤的化学组成明显地受源岩成分、形成过程和形成环境的影响。流域上游基岩的一些特征元素在冲积物土壤中被明显地继承,如海河流域基岩和土壤中的CO2、CaO、MgO、FeO、Sr,鄱阳湖流域基岩和土壤中的W、Sn、Bi、U、Th、Pb、Rb、Tl、As、Sb、Se、Hg、Nb、Ta、Hf、B、Be、Ge、Pt、Pd、Y。受形成过程和形成环境的影响,处于暖温带半湿润季风气候下的海河流域冲积平原土壤以极富集CO2、CaO、Na2O、Cl,显著富集MgO、FeO、Sr,富集P、S为特征;而处于亚热带湿润季风气候下的鄱阳湖流域冲积平原土壤则以显著富集Hg、Se和富集Al2O3、Fe2O3H2O^＋、W、Sn、Bi、Mo、U、Th、Pb、Rb、Cs、Tl、Li、Be、B、Ga、Ge、Nb、Ta、Zr、Hf、As、Sb、Co、Cr、Ti、V、Zn、Pt、Pd、REE、Y为特征。无论是海河流域还是鄱阳湖流域的冲积平原土壤,均富集As、Sb、Hg、B、Cl、W、Sn、Bi、Pb、Se、Ge、Li、Cs、Cu、Au、Fe2O3、V、Cr、Ni、Zr、Hf、Y。  相似文献