Mobilization and Redistribution of Elements in Soils Developed from Extremely Weathered Basalts on the Hainan Island
The Hainan Island is located in a tropical zone and most of the ferralsol profiles that developed on Neogene basalt in this region have undergone extensive weathering. Major, trace and organic elements of a laterite profile were reported to inves- tigate elements mobilization and redistribution in tropical regions. The results indicate that SiOz, A12O3 and Fe2O3 are the dom- inant chemical components, CaO, Na2O, MgO and K2O concentrations are extremely low and CIA and CIW values are high for ali soil samples. These results suggest that the profile has undergone extremely strong weathering. The strongly acidic environ- ment and organic matter (OM) can remarkably improve the transfer of insoluble elements. As for the general conservative ele- ments during incipient chemical weathering, such as Ti, Zr, Hf and Nb, the removals are up to 30%-40% in the upper pro- file; and Fe, A1, Cu and Ni are removed from the upper profile, transferred downwards, and then precipitated in the lower profile. In addition, atmospheric inputs, including sea salt aerosol and dust, have a profound effect on the budgets of elements that are susceptible to leaching-induced losses (e. g. K, Na and Sr). The overall elemental behaviors in this profile suggest that organic matter and atmospheric inputs play a very important role in the mobilization and redistribution of elements during ex- treme weathering in tropical regions.
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万方数据
维普
