1. Holocene vegetation cover in Qin'an area of western Chinese Loess Plateau revealed by n-alkane.
- Author
-
Zhong YanXia, Chen FaHu, An ChengBang, Xie ShuCheng, and Huang XianYu
- Subjects
BIOMARKERS ,PLATEAUS ,HOLOCENE stratigraphic geology - Abstract
Previous studies have found that wetlands prevailed in western Chinese Loess Plateau and pine pollen could reach up to 80% in Qin'an area of the plateau during middle Holocene. It was then deduced that forest vegetation covered Qin'an area in a warm and wet climate during middle Holocene. The proxies of molecule biomarkers from two Holocene sections, a swamp-alluvial loess section and a typical loess-paleosol section are used to reconstruct regional vegetation history. It is found that the heavy-molecular-weight (HMW) homobogues of the n-alkanes in all samples exhibit a pronounced odd-over-even predominance, maximizing at C
31 and the abundance of the nC27 -alkanes is the lowest in nC27 , nC29 , nC31 , i.e. C27 29 31, a typical grass n-alkanes model. The results are the same as those of model surface soil samples under grass cover but different from both forest cover and modern pine leaves, which yield preferentially nC 29 -alkanes peak. It could be inferred that the area was dominated by grass cover but not forest cover during whole Holocene epoch. The study shows that combining both molecule biomarkers and pollen analysis can avoid the disadvantage of pollen analysis in reconstruction of regional vegetation cover. [ABSTRACT FROM AUTHOR]- Published
- 2007
- Full Text
- View/download PDF