本文選題：曹娥江下游 + 粒度�。� 參考：《地理科學(xué)進(jìn)展》2017年04期

【摘要】：基于曹娥江下游星一村鉆孔(XYC)1717個(gè)沉積物樣品的粒度分析,探討錢(qián)塘江南岸地區(qū)全新世沉積環(huán)境記錄。初步結(jié)論如下:1基于粒度組成,XYC孔沉積物分為粉砂質(zhì)砂、砂質(zhì)粉砂、粉砂、粘土質(zhì)粉砂等4種巖性,自下而上分為9個(gè)單元,組成多個(gè)粒度粗細(xì)變化旋回。其中,第1、4兩層為粉砂質(zhì)砂,砂含量高于粉砂,粘粒含量10%~15%,分選差,動(dòng)力條件復(fù)雜;第3、5兩層屬砂質(zhì)粉砂,粉砂為主但含量不超過(guò)70%,砂含量20%以上,粘粒含量低;第2、7、9三層為粉砂,粉砂含量超過(guò)70%,粘粒、砂含量均低于20%;第6、8兩層為粘土質(zhì)粉砂,粉砂含量高于70%,粘粒含量20%以上。2基于C-M圖最大搬運(yùn)動(dòng)能和平均搬運(yùn)動(dòng)能強(qiáng)弱及其變化幅度分析,初步識(shí)別出4種沉積相,自下而上依次為河流相、潮坪相、淺海相、湖沼相。第1、2兩層為高能且不穩(wěn)定的水動(dòng)力搬運(yùn)環(huán)境,屬河流相沉積;第3~7層,最大搬運(yùn)動(dòng)能減弱,搬運(yùn)動(dòng)力與上虞近海灘涂樣品SYTT相似,為潮坪相沉積;第8~9層,搬運(yùn)動(dòng)能低且變幅小,屬低能靜水沉積環(huán)境;第8層下段為淺海相,該層上段至第9層為湖沼相。3粒度縱向變化表明,粘粒含量自下而上波動(dòng)增加;砂含量自下而上波動(dòng)減少,平均粒徑向上變細(xì)、分選性向上變好。XYC孔記錄了該地區(qū)9690~5131 cal.a BP時(shí)段海面上升,達(dá)到高海面繼而又海退的過(guò)程。研究結(jié)果有利于進(jìn)一步探索錢(qián)塘江流域的古環(huán)境演變特征。
[Abstract]:Based on the grain size analysis of 1717 sediment samples from Xingyi Village in the lower reaches of Cao'e River, the Holocene sedimentary environment records in the south bank of Qiantang River are discussed. The preliminary conclusions are as follows: according to the grain size composition, the sediment of XYC pore can be divided into four types of lithology: silty sand, sandy silty sand and clay silty sand, which can be divided into 9 units from bottom to top, forming multiple grain size coarse variation cycles. The first and fourth layers are silty sand, the content of sand is higher than that of silty sand, the content of clay is 10 and 15, the sorting is poor and the dynamic condition is complicated, the third and fifth layers belong to sandy silty sand, the silt content is mainly but not more than 70, the sand content is more than 20%, and the clay content is low. The second and seventh layers are silty sand, the silt content is more than 70, the clay and sand content are lower than 20, and the 6th and 8th layers are clay silty sand, The silty sand content is higher than 70 and the clay content is over 20%. 2. Based on the analysis of the maximum and average transport kinetic energy of C-M diagram and their variation amplitude, four sedimentary facies are identified, which are river facies, tidal flat facies, shallow sea facies and lake-marsh facies from bottom to top. The first and second layers are high energy and unstable hydrodynamic transport environment, which belong to fluvial facies deposit, the third layer is 7 layer, the maximum transport kinetic energy is weakened, and the transport power is similar to the SYTT of Shangyu coastal tidal flat sample, which is tidal flat facies deposit; The transport kinetic energy is low and the amplitude is small, which belongs to the low energy hydrostatic sedimentary environment, the lower part of the eighth layer is shallow sea facies, the vertical variation of grain size from the upper segment to the 9th layer of the lake facies indicates that the fluctuation of clay content increases from bottom to top, and the fluctuation of sand content decreases from bottom to top. The average particle size is finer up, and the sorting property is better up. XYC hole records the process of sea surface rising in the period of 9690 ~ 5131 cal.a BP, reaching high sea level and then retreating. The results are helpful to further explore the paleoenvironmental evolution characteristics of Qiantang River basin.
【作者單位】： 浙江師范大學(xué)地理與環(huán)境科學(xué)學(xué)院;
【基金】：國(guó)家自然科學(xué)基金項(xiàng)目(41371206,41572345)~~
【分類(lèi)號(hào)】：P512.2
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本文編號(hào)：1927219