晚更新世以来海南岛西部河流阶地演化及其成因机制  

The Origin and Evolution of Late Pleistocene River Terracesin Western Hainan Island

作　　者：陈康林[1] 姜涛[1] 胡亦潘 周从艳 梁晨 宋霖 Chen Kanglin;Jiang Tao;Hu Yipan;Zhou Congyan;Liang Chen;Song Lin(Hubei Key Laboratory of Marine Geological Resources,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学海洋地质资源湖北省重点实验室,湖北武汉430074

出　　处：《地球科学》2024年第8期3043-3055,共13页Earth Science

基　　金：国家自然科学基金项目“海绵骨针释光年代学探索及其对晚更新世以来南极绕极流演化的制约”(No.41976073)。

摘　　要：晚更新世以来,海南岛构造活动活跃且差异性构造升降特征明显.受这些构造活动影响,海南岛上各条主要河流发育了一系列河流阶地,深刻理解这些阶地的形成演化过程无疑将有助于更好地揭示海南岛不同部位的构造差异活动特征.运用光释光测年技术对海南岛西部6条河流的河流阶地沉积物进行定年,结合野外地质调查与地貌学研究,系统建立了4级河流阶地年代框架:27.3~29.6 ka、2.82~3.92 ka、0.60~0.93 ka、~0.40~0.50 ka,进而结合海南岛构造活动和区域气候演化等探讨了河流阶地的成因.研究结果表明,T4阶地的形成主要受控于气候变化,它改变了径流搬运能力和沉积物通量,进而导致了河流产生堆积和侵蚀作用;T3、T2、T1阶地的形成受控于多条断裂活动,间歇性的差异性构造升降运动是这些河流阶地形成的主要驱动力,而且河流下切速率差异性表明0.60~3.92 ka海南岛中西部构造隆升速率高于西南部.The Late Pleistocene tectonic activities of Hainan Island appear various vertical movements and results in a series of river terraces developed in the island.The evolution of these terraces can reveal the characteristics of differential structural activities in different areas of Hainan Island.The optically stimulated luminescence(OSL)dating is used to date the river terraces of 6 rivers in the western Hainan Island.Based on a detailed field geological survey and geomorphology researches,the chronological framework of river terraces(27.3-29.6 ka,2.82-3.92 ka,0.60-0.93 ka,~0.40-0.50 ka)are set up.Combined with the tectonic activity and regional climate evolution around Hainan Island,the origin of those river terraces is discussed.The results show that T4 would be mainly caused by the climate changes.Climate changes altered runoff carrying capacity and sediment flux,leading to accumulation and erosion of these rivers.T3,T2 and T1 terraces would be controlled by multiple faults and the key factor for the development of terraces would be the intermittent differential tectonic uplift movement.The difference of river incision rate indicates that the rate of tectonic uplift rate in its mid-western area is higher than those of southwester area during 0.60-3.92 ka.

关 键 词：海南岛 河流阶地 光释光测年 构造活动 气候变化 海洋地质 

分 类 号：P931.1[天文地球—自然地理学]