發(fā)布時間：2018-04-01 19:31

  本文選題：龍門山　切入點：沖積扇　出處：《沉積學報》2017年01期

【摘要】：青藏高原東緣龍門山北東段山前涪江沖積扇在武都盆地內(nèi)的覆蓋面積約為25 km2,區(qū)域構造上為江油斷層、香水—讓水斷層等組成的江油斷裂帶右旋走滑構造域。通過宇宙核素成因埋藏年齡測試技術精確地測定發(fā)源于龍門山北東段主要河流—涪江自第四紀以來發(fā)育的三期沖積扇形成年代,即早更新世沖積扇(1.84 Ma)、中更新世沖積扇(0.54 Ma)和全新世沖積扇。由于龍門山北東段—江油斷裂的右旋走滑兼逆沖運動,導致涪江早更新世沖積扇扇頭右旋錯動約3.2 km,之后形成新的沖積扇(中更新世積扇)。隨著江油斷裂繼續(xù)的繼續(xù)活動,中更新世沖積扇扇頭又被右旋錯動了約0.8 km,之后形成全新世的沖積扇。涪江形成以來總共右旋錯動距離約為4 km。同時,早、中更新世沖積扇褶皺隆升了約50 m,早更新世沖積扇總共褶皺隆升了約100 m。這在一定程度上反映了龍門山構造帶北東段第四紀以來沉積對構造演化的響應過程。
[Abstract]:The Foreland Fujiang alluvial fan on the eastern margin of Longmen Mountain on the eastern margin of the Qinghai-Tibet Plateau covers about 25km2 in the Wudu basin, and the regional structure is a Jiangyou fault. Perfume-dextral strike-slip tectonic domain of Jiangyou fault zone composed of water faults etc. The origin of Fujiang, a major river in the eastern part of Longmen Mountain, developed since the Quaternary by means of the cosmic radionuclide burial age test technique. The age of the formation of the third stage of the alluvial fan, That is, the early Pleistocene alluvial fan is 1.84 Ma, the middle Pleistocene alluvial fan is 0.54 Ma. and the Holocene alluvial fan. Due to the right-lateral strike-slip and thrusting movement of the East Longmenshan fault, This resulted in the right-lateral dislocation of the head of the alluvial fan in the early Pleistocene of Fujiang River, and the formation of a new alluvial fan (the Middle Pleistocene fan). The middle Pleistocene alluvial fan head was about 0.8 km of right lateral dislocation, and then formed Holocene alluvial fan. The total right-lateral dislocation distance since Fujiang formation is about 4 km. The middle Pleistocene alluvial fan fold uplifted about 50 mand the early Pleistocene alluvial fan uplifted about 100 m.This reflects to some extent the process of sedimentary response to the tectonic evolution in the eastern segment of the northern part of the Longmenshan tectonic belt since the Quaternary.
【作者單位】： 曲阜師范大學地理與旅游學院;
【基金】：國家自然科學基金項目(41072164)~~
【分類號】：P542

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本文編號：1696993