本文選題：大同火山 + 沉積地層��； 參考：《上海師范大學》2017年碩士論文

【摘要】：大同火山群位于山(西)陜(西)地塹系最北端的大同盆地中。第四紀時期,大同火山群火山多次噴發(fā),在盆地內(nèi)堆積了大量的火山噴發(fā)物。自上世紀30年代開始,中外學者對大同火山展開了大量的科研工作,在大同火山的地質(zhì)構(gòu)造背景、火山活動類型、巖漿化學成分、火山深度動力學機制及活動年代等方面都取得了眾多研究成果。然而,由于野外采樣困難,火山活躍期次較多等因素的影響,使得目前的火山活動年代數(shù)據(jù)無法形成有效的比對,更不能反映大同火山活動的階段性歷史特征,因此人們對于大同火山的活動期次及年代問題一直爭論不斷。野外調(diào)查發(fā)現(xiàn):火山錐體坡麓附近和泥河灣古湖湖相沉積層與湖岸之上黃土—古土壤沉積層中夾有多層火山碎屑層。(1)在肖家窯火山坡麓位置存在有多套傾角不同的火山碎屑層。且位于底部的火山碎屑層傾角大于其上部碎屑層的傾角。(2)陳莊湖相沉積層和黑山黃土—古土壤沉積層中發(fā)現(xiàn)有多層疑似火山灰物質(zhì)沉積的延續(xù)良好的薄層灰黑色特征沉積層。這些沉積現(xiàn)象表明:大同火山在地質(zhì)歷史時期存在多個活躍期。區(qū)域的湖相沉積和黃土—古土壤沉積都詳細的記錄了當時的火山活動信息。為從沉積地層中獲得更為詳細的火山活動信息、建立沉積剖面的年代框架、判斷沉積剖面中所夾火山物質(zhì)沉積層位的沉積年代。本文對火山群周邊受火山活動影響的湖相沉積層和黃土—古土壤沉積層進行了仔細的野外物理形態(tài)描述和高精度的采樣。我們選取陳莊剖面作為湖相沉積的典型剖面、黑山剖面作為黃土沉積的典型剖面。野外考察中都發(fā)現(xiàn)這兩剖面中存有明顯的火山活動記錄信息,實驗室分析表明這兩個剖面都有多個層位在沉積過程中受到了區(qū)域火山活動的影響。在湖相沉積剖面中出現(xiàn)四層磁化率、Ti元素含量、Fe元素含量和平均粒度組成同步異常變大的沉積層位;在黃土—古土壤沉積剖面中出現(xiàn)三層磁化率、Ti元素含量或Fe元素含量同步異常變大的沉積層位。這些異常變大的現(xiàn)象表明沉積時受到區(qū)域環(huán)境突變的影響。在大同盆地中則是受到火山活動導致的區(qū)域沉積環(huán)境突變。利用古地磁定年法和黃土古土壤定年法建立不同沉積剖面的年代框架,判斷湖相沉積層中四個火山物質(zhì)沉積層的沉積年代分別為:早于0.90MaB.P.、約0.51MaB.P.、約0.32MaB.P.和約0.09MaB.P.;黃土—古土壤沉積層中三個火山物質(zhì)沉積層的沉積年代分別為約0.32MaB.P.、0.19MaB.P.和約0.09MaB.P.。通過沉積層沉積年代比對認為大同火山群共存在五個活躍期,分別為早于0.90M aB.P.、約0.51MaB.P.、約0.32MaB.P.、0.19MaB.P.和約0.09MaB.P.
[Abstract]:Datong Volcano Group is located in the Datong basin at the northernmost end of the Shanshan (West) Shaanxi (West) graben system. During the Quaternary period, the Datong volcanic group erupted many times and accumulated a lot of volcanic eruptions in the basin. Since the 1930s, Chinese and foreign scholars have carried out a great deal of scientific research on Datong volcano. In the geological tectonic background, volcanic activity type, magmatic chemical composition of Datong volcano, Many achievements have been made in the dynamic mechanism and age of volcanic depth. However, due to the difficulty of sampling in the field and the influence of many factors such as the secondary active period of volcanism, the current dating data of volcanic activity can not form an effective comparison, let alone reflect the historical characteristics of the stages of the volcanic activity in Datong. As a result, there has been a constant debate about the active periods and chronologies of Datong Volcano. Field investigation shows that there are multiple layers of volcanic clastic layer located in the loess paleosol sediment layer near the slope of the volcanic pyramidal body and above the lacustrine facies of the ancient lake in Nihewan) and there are several sets of volcanic clastic layers with different dip angles at the foothills of the Xiaojiayao fire slope. Moreover, the dip angle of the volcanic clastic layer located at the bottom is greater than that of the upper clastic layer. The Chenzhuang lacustrine sedimentary layer and the Montenegrin loess-paleosol sedimentary layer are found to have several layers of thin-layer gray-black sedimentary layers with good continuity of suspected volcanic ash deposition. These sedimentary phenomena indicate that there are many active periods in the geological history of Datong volcano. Regional lacustrine deposits and loess-paleosol deposits both recorded the volcanic activity in detail at that time. In order to obtain more detailed volcanic activity information from sedimentary strata, the chronological framework of sedimentary profiles is established, and the sedimentary ages of sedimentary layers of volcanic material in sedimentary profiles are determined. In this paper, the lacustrine sediments and loess-paleosol sediments around the volcanoes affected by volcanic activity were carefully described in the field and sampled with high accuracy. We select Chenzhuang section as typical section of lacustrine facies and Montenegro section as typical section of loess deposit. During the field investigation, it is found that there are obvious records of volcanic activity in the two profiles, and laboratory analysis shows that there are many layers affected by the regional volcanic activity in the sedimentary process of the two profiles. In the lacustrine sedimentary profile, there are four layers of magnetic susceptibility and Ti content, Fe content and average particle size composition. In the loess paleosol sedimentary profile, the three layers of magnetic susceptibility and the content of Ti element or Fe element become larger and larger synchronously. These abnormal phenomena indicate that the deposition is affected by the abrupt change of regional environment. In the Datong basin, the regional sedimentary environment changes due to volcanic activity. Paleomagnetic dating method and loess paleosol dating method were used to establish the chronological framework of different sedimentary profiles. The sedimentary ages of the four volcanic sediments in the lacustrine sediments were determined to be earlier than 0.90 MaB.P., about 0.51MaB.P.and about 0.32MaB.Prespectively. The sedimentary age of the three volcanic sediments in the Loess paleosol sedimentary layer is about 0.32 MaB.P./ 0.19 MaB.P. And about 0.09 MaB.P. Five active periods of the Datong volcanic group, which are earlier than 0.90 Ma B.P., 0.51MaB.P., 0.32 MaB.P.and 0.19 MaB.Prespectively, are considered to exist in Datong volcanic group by comparison of sedimentary ages. And about 0.09 MaB.P.
【學位授予單位】：上海師范大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：P318.44;P317

【參考文獻】

相關期刊論文 前10條

1 江俊;Alaa Salem;賴曉鶴;張衛(wèi)國;Leszek Marks;Fabian Welc;徐立辰;陳靜;陳中原;孫千里;;湖泊沉積物磁學特征指示的埃及Faiyum盆地全新世以來的環(huán)境演變[J];湖泊科學;2016年06期

2 岑敏;董樹文;施煒;周濤發(fā);陳龍;陳興強;;大同盆地形成機制的構(gòu)造研究[J];地質(zhì)論評;2015年06期

3 雷建設;;山西大同火山深部細結(jié)構(gòu)及深部起源[J];國際地震動態(tài);2013年11期

4 李拓宇;莫多聞;胡珂;王海斌;郭媛媛;張翼飛;任小林;;臨汾盆地陶寺遺址附近全新世黃土剖面的環(huán)境指標分析[J];北京大學學報(自然科學版);2013年04期

5 趙華;王成敏;毛洪亮;盧演儔;劉林敬;吉云平;趙紅梅;;大同火山烘烤層的光釋光年齡[J];第四紀研究;2012年03期

6 胡小猛;盧海龍;吳冰;吳潔利;;山西地塹湖盆湖退-湖侵的地貌沉積響應及其構(gòu)造指示意義[J];第四紀研究;2011年06期

7 曾艷;陳敬安;朱正杰;李鍵;;湖泊沉積物Rb/Sr比值在古氣候/古環(huán)境研究中的應用與展望[J];地球科學進展;2011年08期

8 吉云平;劉海坤;閆豐錄;殷夏;王立民;黃遠征;高昀;畢志偉;毛洪亮;;陽原盆地西部梨益溝地層初探[J];南水北調(diào)與水利科技;2010年06期

9 劉青松;鄧成龍;;磁化率及其環(huán)境意義[J];地球物理學報;2009年04期

10 袁寶印;同號文;溫銳林;王燕華;;泥河灣古湖的形成機制及其與早期古人類生存環(huán)境的關系[J];地質(zhì)力學學報;2009年01期

相關碩士學位論文 前2條

1 吳潔利;大同火山活動在湖相沉積和黃土沉積中的記錄研究[D];上海師范大學;2013年

2 許偉;柴達木地塊晚二疊世古地磁結(jié)果及構(gòu)造意義[D];中國地質(zhì)科學院;2012年

，

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