.150 Ka Bp Sarah Usu River Basin Constant Element Distribution Records Of Climate Changes

It exists 38 sedimentary cycles of palaeo-aeolian sands to its overlying fluvio-lacustrine facies or/and palaeosols in the Salawusu River valley of the southeast depression of the Mu Us Desert since 150 ka B.P.. The analytic results of chemical the main elements samples show that, the contents of A12O3> Fe2O3+FeO, Mn, TiO, K20, MgO, CaO, Na2O in fluvio-lacustrine facies and palaeosols are remarkably higher than those hi aeolian sand, and SiO2 takes on contrary changes, composing 38 change cycles of main elements corresponding to sedimentary cycles since 150 ka B.P.. Combining to the migratory character of the main elements, the research area geomorphological character belonging to the southeast depression of the Ordos Plateau and its geographical position lying in monsoon sand area, the paper put forward that: the reason that the content of SiO2 is higher and the content of A12O3, Fe2O3+FeOi Mn, TiO, K2O, MgO, CaO, Na2O is lower in the aeolian sands, is the great number of SiO2 moved hi during the cold-dry climate; whereas the move of SiO2 and the gather of stable constant elements A1203, Fe2O3+FeO, Mn, TiO hi fluvio-lacustrine facies and palaeosols is related to the biochemistry weathering during warm-humid climate, hi the 38 sedimentary cycles, the contents of non-stable K2O, MgO, CaO, Na2O hi the fluvio-lacustrine facies are usually higher than those in the aeolian sands, it shows that during warm-humid climate, precipitation is abundant, the earth's surface around is drenched and washed out, so them can be assembled to the special close lowland. All study shows that 38 element change cycles hi the Salawusu River valley since 150 ka B.P. are related to the repeatedly mutual alternation in the Mu Us Desert between Asia winter monsoon and summer monsoon in the northern hemisphere during the glacial period and interglacial period. The 38 sedimentary cycles record 38 climate vicissitudes between cold-dry and warm-humid.The paper also makes a preliminary contrast between the constant elements average value of different time and oxygen isotope phases. The result shows that at warm phases as 18O1, 8 18O3 and 18O5 , the value of SiO2 content is lower, values of Al2O3, Fe2O3+FeO, TiO, Mn, CaO, MgO, Na2O, K2O are higher, at cold phases as 8 18O2, 8 18O4 and 6 18O6, they manifest contrary changes. Sub-phase of 8 18O5 also shows similar change situation: in warm phases as 8 l8O5a, 8 l8O5c and 8 18O5e, SiO2 assumes lower content value, Al2O3, Fe2O3+FeO, TiO, Mn, CaO, MgO, Na2O, K2O assume higher content value; but in cold phases as 8 18O5b and 8 18O5d, the value of SiO2 content is higher, and those of Al2O3. Fe2O3+FeO, TiO, Mn, CaO, MgO, Na2O, K2Oare lower. It indicates that the regional climate change hi the Salawusu River valley denoted by the main elements character and their content variety, exits well coupling relation with oxygen isotope phases since 150 ka B.P.. So we consider that the climate condition of multi-cycles of cold-dry and warm-humid and its changes posted by chemical elements hi the Milanggouwan stratigraphical section since 150 ka B.P., exist the relation of origin with the cold-warm phases of past global temperature changes, at least on the larger time range.