作　　者： ; ; ;

机构地区： 中山大学地球科学系

出　　处： 《地球化学》 2003年第2期146-154,共9页

摘　　要： 在对深圳地区SX97孔进行沉积物岩相分析和磁性测试的基础上,结合Fe元素含量、石英和粘土矿物含量变化,对钻孔进行了高频层序地层分析。结果表明,钻孔可以划分为1个四级层序(准层序)和6个五级层序。每个层序代表了一次海平面的升降旋回。四级层序的海退沉积与末次冰期的后期对应,海平面下降最大时期是末次冰期最盛期(LGM)的反映,时间大约在21kaB.P.左右;海侵沉积对应着气候的回升,发生在约13.8kaB.P.。在四级层序的海退沉积中,包含2个五级层序,实质上反映了两次气候的暖、冷旋回,但从时间上无法与Heinrich事件相对比。在四级层序的海侵过程中,包含4个比较明显的五级层序,也是4次比较明显的气候变化旋回。其中,从五级层序4的海侵开始到五级层序5的海侵结束,时间约从6.5～2.3kaB.P.,是全新世气候最适宜期,之后从2.3～1.7kaB.P.是气候相对变冷时期。这些主要气候事件与我国其他地区的非同时性,反映了东亚季风和印度季风等对深圳地区气候变化的多重控制作用。 Core SX97 is located in Shenzhen region of South China. The length of the core is about 30.6 m. The sedimentary successions of the core comprise, from the base, the artificial soils (about 0～ 3.85 m), the Quaternary sediments composed of the marine and continental facies (3.85～ 26.04 m), and the regolith (about 26.04～ 30.6 m). The Quaternary sediments are mainly focused on in this study. The magnetic characteristics of the sediments show that the susceptibility are controlled dominantly by magnetite, hence the fraction of magnetite in sediments are mainly responsible for the magnetic susceptibility changes. The susceptibility of fine grain sediments, such as clay and silty clay, is high; and that of the coarse grain sediments, such as sand and coarse sand, is low. Based on this result mentioned above, and referring to the analysis of quartz and clay minerals, sequence stratigraphical approach has been applied to analyze the architecture of sedimentary successions, and several high resolution sequences, including one parasequence and six fifth level sequences, has been identified. Each sequence correlates to a relative sea level rising and falling cycle. The regressive period of the parasequence was the late stage of the Last Glacial, when two fifth level sequences correlated with two climatic cycles from warm to cold without Henrich events. The maximum of sea level falling happened in the period of LGM. The transgressive period of the parasequence corresponds to the time when climate had became warmer gradually from about 13.8 ka B.P. to present, when four fifth level sequences also correlated with climatic changes. The Holocene optimum was recorded in the succession from the transgressive of the fifth level sequence 4 to the end of the transgressive of the fifth level sequence 5 (during about 6.5～ 2.3 ka B.P.), and one cold event (maybe the first cold event of Neoglaciations) existed during 2.3～ 1.7 ka B.P. The asynchronism of these main climatic events with North China revealed

关 键 词： 海平面变化 古气候 季风 广东 深圳市 沉积物

领　　域： [天文地球] [天文地球] [天文地球] [天文地球]