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Pedosedimentary development and palaeoenvironmental significance of the S1 palaeosol on the northeastern margin of the Qinghai‐Xizang (Tibetan) Plateau
Author(s) -
KEMP ROB A.,
DERBYSHIRE EDWARD,
FAHU CHEN,
HAIZHOU MA
Publication year - 1996
Publication title -
journal of quaternary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.142
H-Index - 94
eISSN - 1099-1417
pISSN - 0267-8179
DOI - 10.1002/(sici)1099-1417(199603/04)11:2<95::aid-jqs221>3.0.co;2-q
Subject(s) - geology , paleosol , pedogenesis , bioturbation , loess , sedimentary depositional environment , period (music) , geochemistry , arid , plateau (mathematics) , paleontology , geomorphology , soil water , soil science , structural basin , mathematical analysis , physics , mathematics , sediment , acoustics
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 northeastern margin of the Qinghai‐Xizang (Tibetan) Plateau in China. Detailed micromorphological analysis of closely spaced thinsections from the pedocomplex at this site provides the basis for reconstruction of the sequence of pedosedimentary processes and associated palaeoenvironmental changes occurring during this time interval. The six pedosedimentary stages identified are interpreted in terms of temporal variations in depositional rates, size of particles transported and availability of moisture for pedogenic alteration, as determined by changing balances in dominance of winter and summer monsoonal forces. Two main ‘soil‐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 corresponds to pedosedimentary stages 4 and 5, when leaching and bioturbation processes were active at aggrading surfaces, leading to development of an accretionary unit without clear differentiation of horizons. Pedosedimentary stages 1, 3 and 6 were characterised mainly by rapid rates of coarse loess accumulation, with synsedimentary modification restricted to surface slaking and crust formation, and minor localised redistribution of calcite.