广东封开河儿口盆地的古地理环境初探

A Study on the Paleogeographic Environment of Heerkou Basin in Fengkai of Guangdong

渔涝河的上游干流—七星河长 4 2km ,在中更新世中期至晚期形成。峒中岩、黄岩洞和罗沙岩等洞穴的动物群化石测龄 14 8～ 2 2 4kaBP ,时间跨度约 13万a而该化石堆积层的厚度仅 1m余 ,且与七星河的第一级阶地类高 ,反映晚更新世早期至中期该盆地底部的构造升降基本上稳定。这是同期广东许多河谷地段没有构造抬升的一个重要信息 ,而且可将今日广东第一阶地沉积的最老年龄从目前已知的 5 1 9kaBP推延伸到 15 0kaBP。

Qixinghe River is the upstream mainstream of the Yulaohe River.The river,with a length of 42 km,was formed in the middle stage and late stage of Middle Pleistocene.The fossil ages of the animal groups in the caverns of Dongzhongyan, Huangyandong and Luoshayan are 148～22 4 kaBP,in the time lasted about 130 ka, but the thickness of the fossil accumulation layer in caverns is only a little more than 1 m,and the altitude of the layers is similar to the first terrace of the Qixinghe River.It is reflected that tectonic uplift and subsidence in the basin bottom are basically \{stable\} from early to middle stage of Late Pleistocence.This is important information without tectonic uplift along many valleys in Guangdong in the same stage.And today, the oldest age of the sediment of the first terrace in Guangdong from known 51 9 kaBP can be extended by guess to 150 kaBP.