Ra. Kemp et al., PEDOSEDIMENTARY DEVELOPMENT AND PALEOENVIRONMENTAL SIGNIFICANCE OF THE S1 PALEOSOL ON THE NORTHEASTERN MARGIN OF THE QINGHAI-XIZANG (TIBETAN) PLATEAU, JQS. Journal of quaternary science, 11(2), 1996, pp. 95-106
The S1 pedocomplex, correlated to Oxygen Isotope Stage 5 of the ocean
cores, has been traced west of the Loess Plateau on to the extreme nor
theastern margin of the QinghaiXizang (Tibetan) Plateau in China. Deta
iled micromorphological analysis of closely spaced thin-sections from
the pedocomplex at this site provides the basis for reconstruction of
the sequence of pedosedimentary processes and associated palaeoenviron
mental changes occurring during this time interval. The six pedosedime
ntary stages identified are interpreted in terms of temporal variation
s in depositional rates, size of particles transported and availabilit
y of moisture for pedogenic alteration, as determined by changing bala
nces in dominance of winter and summer monsoonal forces. Two main 'soi
l-forming intervals' are identified: the more extensive of the two in
terms of resultant pedological features reflects pedogenic alteration
at a relatively 'stable' land surface under a semi-arid climate during
the later part of pedosedimentary stage 2. The other main period corr
esponds to pedosedimentary stages 3 and 5, when leaching and bioturbat
ion processes were active at aggrading surfaces, leading to developmen
t of an accretionary unit without clear differentiation of horizons. P
edosedimentary stages 1, 3 and 6 were characterised mainly by rapid ra
tes of coarse loess accumulation, with synsedimentary modification res
tricted to surface slaking and crust formation, and minor localised re
distribution of calcite.