Publication Date:
2012-04-01
Description:
Saline alkaline sediments and soils are widespread in arid and semiarid regions, but their occurrence in ancient dry periods remains unknown due to the lack of a suitable proxy. On the basis of investigations of modern Chinese soils with a wide pH range of 3.5–9.1, we suggest that the microbial lipid ratio Ri/b, i.e., the abundance ratio of archaeal isoprenoid GDGTs (glycerol dialkyl glycerol tetraethers) to bacterial branched GDGTs, indicates the presence of drought-induced alkaline deposits in terrestrial settings. The Ri/b is invariant in modern soils with pH 〈 7.5 and when the local mean annual precipitation 〉600 mm, but it increases sharply at higher pH values and lower mean annual precipitation (
Print ISSN:
0091-7613
Electronic ISSN:
1943-2682
Topics:
Geosciences
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