| Popis: |
Holocene moisture evolution in the arid Central Asia region, dominated by the westerly circulation system, has been shown to be in drastic contrast with that in Asian monsoonal regions. Yet, water isotope records, including stalagmite oxygen isotopes and terrestrial long-chain n-alkane/acid hydrogen isotopes, show many common features in the two regions. Here we present several new isotopic records from the arid Central Asia region to examine the isotopic differences from various archives/media, together with existing water isotopic records from both regions. Isotopic records more reflecting terrestrial signal in arid regions appear to follow the pattern in monsoonal regions, while those likely affected by isotopic enrichment due to lake water evaporation display various patterns, and not necessarily resemble moisture changes inferred from the same lakes. It thus appears that the terrestrial water isotopes in both regions may record the isotopic signature in precipitation, but not necessarily linked to aridity changes. Meanwhile, those isotopic records affected by lake evaporation, after subtracting the original precipitation isotopic signal, show good correspondence to moisture changes. |
