摘要
井头山遗址属于海相沉积环境下的史前遗址,出土的遗物中包括一百余件饱水木器以及十余件由芦苇、芒草等为原料制作的编织物.编织物被遗址土壤包裹,并与遗址土壤之间存在粘结现象,这为编织物的提取带来困难.对遗址土壤的矿物组成、有机质和去离子水浸渍液进行了分析测定.分析结果表明,遗址土壤呈碱性,有较高的可溶盐含量,所测土壤样品具有相似的矿物组成与含量,遗址土壤中存在的铁氧型矿物以及胡敏酸、富里酸等腐殖质是重要的胶结物质,这些胶结物质的存在致使遗址土壤不易分散.根据分析结果,在温和条件下选用羟基吡啶酮衍生物(简称HRP)作为脱铁络合剂对遗址土壤进行脱铁处理,进行遗址土壤分散方法预研究.分散方法预研究结果表明,在温和条件下,30 mmol/L HRP即可以对遗址土壤进行有效地分散,这种分散方法可以为编织物的提取提供参考.
Abstract
The cultural layer of the Jingtoushan site dates back about 7 800-8 300 years,approximately 1 000 years prior to the Hemudu culture.As a prehistoric shell mound site that has never been discovered in previous archaeological work in Zhejiang region,the Jingtoushan site was selected as one of the top ten new archaeological discoveries in 2020.The cultural accumulation of the Jingtoushan site is 5-10 m below the sea level and is covered with thick saturated marine sedimentary silt.The cultural remains include ash pits and food storage pits,shell deposits,utensil processing and food processing sites,etc.The relics unearthed from the site include more than 100 wooden objects such as oars,handles and pestles,as well as more than ten woven fabric such as mats,baskets,pack baskets,fish covers,fans,fishing nets and fine ropes.The woven fabric are made from reeds,awn grass,bamboo and other raw materials,and are scattered in the marine silt along with various relics.Due to various factors in the burial environment,the woven fabric have undergone severe degradation,resulting in structural decay and fragility and reduced mechanical strength,posing significant challenges for safe separation and extraction.Taking the cohesive soil of the Jingtoushan site as the research object,various analysis methods such as X-ray diffraction,potentiometric titration and ion chromatography were used to analyze the mineral composition and contents of the site soil,the content of organic matters and humic substances such as humic acid and fulvic acid,as well as the ion contents and pH value of the soil impregnation solution.The analysis results indicate that the soil at the site is alkaline,with similar X-ray diffraction peaks,mineral composition and contents,and high contents of organic matter and soluble salts.The presence of iron oxides in soil clay minerals,as well as humic substances such as humic acid and fulvic acid in organic matters,are important soil binding substances,causing the soil texture of the site to be cohesive and difficult to disperse,which is not conducive to the separation and extraction of fragile woven fabric.In order to safely separate and extract fragile woven fabric,it is necessary to convert organic or inorganic soil binding substances in the soil to reduce the binding effect on soil particles.Organic binding substances in soil can be treated with oxidants or alkaline solutions to make the organic matters in the soil to be oxidized and decomposed or converted into soluble salts,thereby achieving the dispersion of cohesive soil.However,this method of decomposing and transforming soil organic matters through oxidants or alkaline solutions,while completing soil dispersion,will inevitably bring potential harm to fragile woven fabric.In addition to humic organic binding substances such as humic acid and fulvic acid,there are also inorganic binding substances present in the form of iron oxides in cohesive soils.In the pre-study of soil dispersion methods,HRP with(O,O)as the coordinating atom was selected as a complexing agent for the Fe element,and the inorganic binding substances in the form of iron oxides were complexed and transformed at the room temperature.The research results indicate that under mild conditions,30 mmol/L HRP could effectively disperse cohesive soil.This dispersion method could provide a reference for the separation and extraction of woven fabric unearthed from the Jingtoushan site and other similar sites.
维普
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