南极布兰斯菲尔德海峡11.25万年来气候演变初探

PRELIMINARY STUDY ON PALEOCLIMATIC CHANGE OF BRANSFIELD STRAIT, ANTARCTICA FOR PAST 112 500 YEARS

南极布兰斯菲尔德海峡PC10岩心代表了112.5 ka B.P.以来的沉积记录。通过硅藻、氧同位素和磁组构参数的定量分析,表明沉积记录对气候变化的反应十分敏感。岩心包含了氧同位素1～5期,古气候演变史大致可分为12个带:末次间冰期的暖高峰期(112.5～106.4 kaB.P.)、第一冷期(106.4～101 ka B.P.)、第一暖期(101～92 ka.B.P.)、第二冷期(92～84 ka.B.P.)和第二暖期(84～75 ka B.P.),末次冰期的早冰期(75～59 ka B.P.)、间冰期(59～24 ka B.P.)、晚冰期(24～14 ka B.P.)、波林-阿洛德(Bolling-Allerod)暖期(14～12 ka B.P.)和新仙女木(Younger Dryas)冰期(12～10 ka B.P.),冰后期的温暖期(10～2.4 ka B.P.)和2320 a B.P.左右的寒冷气候事件。该12个古气候带与全球晚更新世以来的气候变化情况基本一致。

The piston core PC10 recovered from the Bransfield Strait .Antarctica recorded the de- position of this area during the past 112. 5 ka B. P. ,representing oxygen isotope stages 1～ 5 and including one incomplete glacial/interglacial cycle and postglacial period. The charac- teristics of diatom floras,oxygen isotope and magnetic fabric parameters show that the se- dimental records are sensitive to the paleoclimatic change. The palecolimatic evolution his- tory may be divided into 12 zones:the peak warm (112. 5～106. 4 ka B. P. ),the first cold (106.4～101 ka B. P. ) ,the first warm (101 ～92 ka B. P. ) ,the second cold (92～84 ka B. P. )and the second warm (84～75 ka B. P. )period of the last interglacial stage,the early subglacial (75～59 ka B. P. ),the sub-interglacial (59～24 ka B. P. ),the late sub-glacial (24 ～14 ka B. P. ),the Bolling-Allerod (14 ～ 12 ka B. P. )and the Younger Dryas (12～10 ka B. P. )period of the last galcial stage,the warm (10～2.4 ka B. P. )period and the cold climate-event occuring at about 2320 a B. P. of the postglacial stage. The 12 zones are cor- respondence with the globe change of climate since Late Pleistocene.