ISSN:
1573-5117
Keywords:
China
;
limnology
;
paleolimnology
;
Pleistocene
;
sediment geochemistry
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Qilu Hu is a large (A = 36.9 km2), shallow (zmax = 6.8 m) lake that lies at an elevation of 1797 m above msl on the Yunnan Plateau, southern China. Lake waters are hard (Mg = 3.2m eq L−1, Ca = 1.3 meq L−1 ), fresh (conductivity = 380 μS cm −1), and productive (Secchi 〈 40 cm). An 11-m sediment core has a basal 14C age of 30960 ± 860 B.P. Sediments between 11 m and 6 m are high in % dry weight, rich in clay components Al2O3, Fe2O3, K2O, MgO, and low in organic C (≤6.1%), carbonate-C (〈1.0%), total N (〈3.2 mg g−1), and total S (〈-1.7 mg g−1). Diatoms and pollen indicate open-water conditions between 9.0 m and 6.0 m (1342011790 B.P.). Above 6.0 m, CaCO3 and organic matter concentrations increase relative to clastics. The transition marks a change to shallow-water conditions as inferred from diatoms and pollen, and probably reflects a shift to drier climate. Uppermost (80-0 cm) red clays were deposited rapidly, probably as a consequence of recent (decades to centuries) riparian disturbances (e.g. agriculture, lake-bottom reclamation, urban development). Dates assigned to events in the Qilu Hu profile are tentative because of potential hard-water-lake error.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00050968
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