东亚和东南亚第四系时间界面的建议

在东亚和东南亚第四系对比中,有关的几条界限,本文建议如后。采用Globorotalia truncatulinoides的初现位作为本区海相第四系的下界,其位置大致在古地磁Olduvai亚时的下界,时间约为距今1.9Ma。在南中国海、东海及沿岸地区,发现了以G.truncatulinoides的初现位为代表的一系列有意义的生物事件,如Pulleniatina finalis的初现位,Globigerinoides obliquus和Globoquadrina altispira的灭绝位,以及Globorotalia menardii和Pulleniatina obliquloculata壳体旋向的变化。此界限在东亚和东南亚也是相当稳定的。在陆相地层中,以泥河湾组为代表,狭义的泥河湾动物群(相当于晚维拉方动物群)所在地层的底界,其古地磁位置为Olduvai亚时的底界。以此作为陆相第四系的下界,与上述海相第四系底界一致。 以古地磁布容/松山界线作为中更新世和早更新世的界限,其年代为0.73MaB.P.。中国中更新世的标准地层周口店组,其底界恰为布容/松山的转换面,北京猿人的年代为0.60—0.23MaB.P.。在洛川黄土剖面上,布容/松山界线为古土壤S_7的底界。雷琼地区中更新统下部的北海组的底界也是布容/松山界线,所产的玻璃陨石的裂变径迹年龄为0.687—0.733MaB.P.。在黄海,布容/松山界线是第Ⅶ海侵层的顶界。通过岩石地层标志,以及动物群、古人

PROPOSED TIME LINES FOR QUATERNARY CORRELATION IN EAST AND SOUTHEAST ASIA

The time lines for Quaternary correlation in East and Southeast Asia are proposed in this paper. The FAD of Globorotalia truncatulinoides could be taken as the lower boundary of marine Quaternary which is approximately identical with the lower boundary of geomagnetic Olduyai Subchron (about 1.9Ma B. P.) corresponding to the beginning of Late Villafranchian in terrestrial Quaternary. The line of Middle Pleistocene/Lower Pleistocene is placed at the geomagnetic boundary of Brunhes/Matsuyama (0.73Ma B. P.). 127 ka B.P., the beginning of Oxygen isotopic stage 5 is proposed as the time line of Late Pleistocene/Middle Pleistocene which corresponds to the beginning of the Last Interglacial Period in Europe. The Holocene/ Pleistocene boundary should be 10 ka B. P. proposed by INQUA. Special attention should be paid to some important geological events which are of universal significance in correlation in the region, such as marine transgressive bed, euolution of fauna and flora, fluctuation of climate and tektite etc.