科研之友
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摘要
The Tianyang Lake in Leizhou Peninsula is an enclosed crater formed during the Early to Middle Pleistocene. Over 200 m of diatomaceous mud and clay were deposited in the last 400,000 years, providing a continuous Middle and Late Quaternary lacustrine sequence for paleoenvironmental studies. The pollen record spans the last four glacial-interglacial cycles equivalent to Oxygen Isotope Stages (OIS) 10 to 1. During most of the glacial phases, Fagaceous monsoon forest was replaced by altitudinal vegetation, indicating a regional landscape transformation on the peninsula. The montane forest reached down to the lowland by at least 600 m during the OIS 6 and 8 in a cool and relatively wet condition, with temperature estimated to be more than 4 degrees C lower than present. A further lowering of the montane forest belts by about 800-1000 m occurred in the OIS 4-2, as implied by the appearance of many temperate elements. During the Last Glacial Maximum, this mixed forest subsequently gave way to the Poaceae grassland, a savanna vegetation type favored by drier and cooler climatic conditions. This drastic change implies a more significant drop in temperature and precipitation than the previous three glacial periods (OIS 10, 8 and 6). It is thus inferred that the weakening of summer monsoon was mon significant towards the end of the Late Pleistocene particularly during the Last Glacial Maximum (LGM).
- 出版日期1999-2-1
- 单位中山大学
