發(fā)布時(shí)間：2018-05-08 14:44

  本文選題：河套地區(qū) + 黃河古河道　； 參考：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：古河道的遷移擺動記錄著河流系統(tǒng)的自身發(fā)育歷史,同時(shí)又反映古地理環(huán)境與地貌的演變過程。黃河古河道是河套平原區(qū)第四紀(jì)水文網(wǎng)的重要組成部分,為全新世河套平原地貌演化的重要證據(jù),而全新世黃河古河道的遷移擺動則對反演河套盆地水系演化、氣候變遷及新構(gòu)造運(yùn)動具有重要的研究意義。本文通過Landsat8遙感影像解譯、1:5萬野外地質(zhì)地貌調(diào)查、鉆孔資料分析,結(jié)合剖面實(shí)測、物探等技術(shù)手段,精準(zhǔn)的圈定了黃河地表及埋藏古河道的分布位置;采用OSL與14C測年較精確地確定了黃河古河道的年代,對全新世黃河古河道進(jìn)行分期,以此獲得了本區(qū)古河道豐富的古地理信息,并最終對黃河古河道遷移演化的成因機(jī)制進(jìn)行了詳細(xì)的探討。全新世以來黃河古河道可分為五期:Ⅰ期古河道,分南北兩支,南支分布在復(fù)興鎮(zhèn)西北部,埋深2~6m,北支分布于呼勒斯太中南部,埋深8.2~9m,時(shí)代為9.93~7.4kaB.P.;Ⅱ期古河道,河道主體分布在色爾騰山山前,埋藏于現(xiàn)今烏加河古河道下部4~11m處。在塔爾湖區(qū)分布有同一期的古河道,埋深7~9m,時(shí)代7.4~4.1kaB.P.;Ⅲ期古河道,呼勒斯太中部、塔爾湖中南部及復(fù)興鎮(zhèn)南部都曾發(fā)育,但河道主體為塔爾湖區(qū)的古河道,埋深2~9m,時(shí)代為4.1~1.2kaB.P.。Ⅳ期古河道,埋藏深度為2.5~4m,主體分布在復(fù)興鎮(zhèn)地區(qū),自西南向東北并折向東南,時(shí)代為1.2~0.4kaB.P。Ⅴ期古河道(現(xiàn)今黃河),沿鄂爾多斯北緣斷裂自西而東流,河道游蕩形成了寬約4~5km東西向河道區(qū)域,近期經(jīng)人類修筑,河道趨于穩(wěn)定,時(shí)代為0.2kaB.P~至今。近萬年來,黃河在河套地區(qū)頻繁改道,遷移的整體路徑呈現(xiàn)由陰山山前逐漸向南遷移、最后擺動至現(xiàn)今河道的趨勢。遷移的具體過程為早全新世的南北兩支古河道向南微弱的遷移趨勢,且分散為南、中、北三支河道;至晚全新世早期的以塔爾湖為中心的大范圍網(wǎng)格狀河道水系,到晚全新世中期的古河道又減少為南北兩支,且北支逐漸由主流級別降為支流,最后晚全新世晚期至今的北部北支河道干涸,形成南支為主流的現(xiàn)代黃河形態(tài)。河道遷移演化的其主控因素為活動斷裂及古地震活動導(dǎo)致的地表不穩(wěn)定,同時(shí)全新世的氣候干濕多變導(dǎo)致的水文變化及后期人類活動的影響也是黃河古河道遷移的重要影響因素。
[Abstract]:The migration and wobble of paleochannel record the development history of the river system and reflect the evolution process of paleogeographic environment and geomorphology at the same time. The paleochannel of the Yellow River is an important part of the Quaternary hydrological network in the Hetao Plain, which is an important evidence of the geomorphologic evolution of the Holocene Hetao Plain. The migration and swing of the paleochannel of the Yellow River in the Holocene can reverse the evolution of the drainage system of the Hetao Basin. Climate change and neotectonic movement are of great significance. In this paper, the distribution of the surface and buried paleochannel of the Yellow River is accurately delineated by the interpretation of the Landsat8 remote sensing image, the field geological and geomorphological investigation, the analysis of the borehole data, the combination of the profile measurement, geophysical prospecting and other technical means. By using OSL and 14C dating, the paleogeography of the Yellow River is accurately determined, and the paleogeographic information of the paleo-channel in this area is obtained by stages of the Holocene Yellow River. Finally, the formation mechanism of paleochannel migration and evolution of the Yellow River is discussed in detail. Since the Holocene, the paleochannel of the Yellow River can be divided into five periods: stage I, paleochannel, divided into north and south, the southern branch is located in the northwest of Fuxing town, the buried depth is 2 ~ 6 m, the north branch is distributed in the central and southern part of Hulas, the buried depth is 8.2 m, and the age is 9.93 ~ 7.4kaB.P. The main body of the river is located in front of the Serten Mountains and buried at 411m in the lower part of the ancient channel of the present Wujia River. In the Tal Lake region, there are ancient rivers in the same period, with a buried depth of 7 ~ 9 m and an age of 7.4 ~ 4.1 kaB.P.; in the third stage, the paleochannel, the central part of Hulatai, the central part of Lake Tal and the southern part of Fuxing Town, are all developed, but the main body of the channel is the paleochannel of Tal Lake area. The buried depth is 2 ~ 9 m, the age is 4.1 ~ 1.2kaB.P..鈪，

本文編號：1861812