人为—生物源元素在开封古城黄泛地层沉积旋回划分中的指示意义  

Sedimentary cycle division from the Yellow River sediments under Kaifeng based on anthropogenic-biogenic elements

作　　者：马建华[1,2] 陈彦芳[1] 谷蕾[1] 刘德新[1] 吴朋飞[2] 

机构地区：[1]河南大学资源与环境研究所,开封475004 [2]黄河文明河南省协同创新中心暨河南大学黄河文明与可持续发展研究中心,开封475001

出　　处：《地理研究》2017年第6期1147-1158,共12页Geographical Research

基　　金：国家自然科学基金项目(41171409);教育部人文社会科学重点研究基地重大项目(12JJD790023);教育部和河南省共建河南大学项目(SBGJ090101)

摘　　要：科学地划分黄泛地层沉积旋回是阐明开封古城兴衰与黄河水患关系的关键,但黄泛地层的粒度层序往往被后期人类活动所扰动,需要探索其他代用指标。在开封老城区的河南大学师专(ZKsz)和医专校区(ZKyz)以及西郊的金明校区(ZKjm)分别钻取25 m连续岩芯,共获得657个样品。用ICP和AFS法测定样品14种元素含量,以人为—生物源元素综合富集系数(IEF)为代用指标,应用小波分析技术划分沉积旋回。结果表明:岩芯Ni、Cr、Fe、Mn、Co、V和Al是自然源元素,Cd、Pb、Cu、Zn、Hg、As和P是人为—生物源元素。郊区岩芯的粒度(砂黏比)旋回与元素旋回的数目和界限相一致,指示IEF可以作为划分沉积旋回的代用指标。城区ZKsz岩芯0~12 m和ZKyz岩芯0~9 m的元素旋回分别为8个和6个,均多于其粒度旋回,IEF可以规避粒度层序紊乱的干扰,元素旋回能够准确反演黄河泛滥次数。现今开封老城区地下的战国大梁城、北宋东京城、明末开封城和清末开封城古地面分别在10~12 m、9 m、4 m和1 m左右。Division of sedimentary cycles from the Yellow River sediments under Kaifeng City is the groundwork to illustrate the relationship between the decline of Kaifeng City and the Yellow River floods in history. However, traditional method dividing sedimentary cycle with granularity cannot be used to the sediments under the city because the normal granulometric sequence of the sediments were disturbed significantly by human activities, such as city reconstructions, looking for treasures buried in sediments, etc. after flood events. Therefore we must discover other proxy indicators instead of granularity to divide flood sedimentary cycles in urban areas. Three sedimentary cores （ZKsz, ZKyz and ZKjm） of 25 m were drilled in April, 2012. ZKsz and ZKyz are in the central urban area of Kaifeng City, and ZKjm is in the western suburbs of the city that is the reference core on the study. The core sections were split fresh in the field at most 10 cm interval and a total of 657 samples were acquired and stored in sample boxes. Concentrations of Pb, Cd, Cu, Zn, Ni, V, Cr and Co in samples were measured with the instrument of Inductively Coupled Plasma-Mass Spectrometry （ICP-MS）, Mn, AI, Fe, and P with Inductively Coupled Plasma-Atomic Emission Spectrometry （ICP-AES）, and Hg and As with Atomic fluorescence spectrometer （AFS）. The integrated enrichment factor （IEF） of elements from human and biology was defined in this paper. With 1EF as a proxy indicator, sedimentary cycles were divided based on the wavelet analysis with the help of MATLAB 7.0 software. The results show that the elements of Ni, Cr, Fe, Mn, Co, V and AI in cores are primarily of natural sources, while Cd, Pb, Cu, Zn, Hg, As and P are anthropogenic-biogenic elements from human activities and biology. Most boundaries of the sedimentary cycles divided by granularity （sand-clay ratio） in ZK^z and ZKyz are consistent with IEF in ZKjm less disturbed by human activities, indicating IEF can be used as a proxy indicator dividing sedimentary cycles.

关 键 词：黄泛地层 人为—生物源元素 沉积旋回 代用指标 开封 

分 类 号：P512.2[天文地球—地质学]