This paper focuses an the relationship between initial 234 U/238 U in stalagmites and paleoclimate reconstructions based on 272 precise ICP-MS 230Th data collected from nine big stalagmites in the Dongge Cave (108°5′E, 25°17′N), Yamen Cave (107°54′E, 25°29′N) and Lianhua Cave (109°32′E, 29°08′N) in southwestern China. The initial 234 U/238 U ratios in stalagmites have a parallel relation to δ18O records of SPECMAP and keep a negative relation to summer insolation for 25°N in long term records. The (234 U/238 U)0 in stalagmites fluctuated slowly during interglacial periods and intensively in glacial periods; during transitional stage between glacial and interglacial, the (234 U/238 U)0 in stalagmites shifted sharply. The (234 U/238 U)0 in stalagmites records BA warm events and YD chill events from the Last Glacial to Holocene, which is consistent with the long term (234 U/238 U)0 records, with heavier ratioes of stalagmites during chilling events and lighter ratioes of stalagmites during warm events. Initial 234 U/238 U ratios of stalagmites formed in a closed cave system are similar to δ18O values of the cave stalagmites from the same area, in contrast, the both in the southwestern regions of China display weak negative relationship with summer monsoon changes. (234 U/238 U)0 in stalagmites may be used as a useful proxy for long-term records of paleoprecipitation.
|Original language||English (US)|
|Number of pages||10|
|Journal||Acta Geologica Sinica|
|State||Published - May 15 2008|
- Initial U / U
- Southwestern China
- Uranium isotopes