广东田洋火山口湖的晚第四纪沉积特征与环境变化

LATE QUATERNARY SEDIMENTARY FEATURES AND PALEOENVIRONMENTAL CHANGES IN THE TIANYANG VOLCANIC LAKE BASIN,GUANGDONG PROVINCE

本文主要依据沉积岩性、沉积时代及生物化石资料讨论田洋火山口湖盆地约13万年以来的沉积特征、自然环境变化以及二者之间的关系.

The Tianyang volcanic lake basin in the south end of the Leizhou Penin-sula, Guangdong Province, is a closed small basin with the diameter of about 2km. Based on the data of drilling, paleomagnetic stratigraphy, radiocarbon dating, diatom and sporopollen analysis, the thickness of deposits formed during the last 130,000 years is about l34m. The lower part is composed of a set of shallow lacustrine deposits. The middle and the upper parts (since 46,000 a. B. P.) are made up of swamp and fluvial deposits intercalated with mud flow accumulations. The climatic fluctuations during the last 130,000 years are also quite marked in the Tiacyang vblcanic lake area. Palynological studies show that there were three cold stages, corresponding respectively to the isotopic stages of 2, 4, and 5d, with a winter temperature drop of 11-14. This is a result from the strengthened winter monsoon in the cold stages.