GEOCHEMISTRY OF TRACE ELEMENTS OF THE QUATERNARY SEDIMENTS OF YAOSHANG FORMATION IN WEINING COUNTY, GUIZHOU PROVINCE AND ITS PALEOENVIRONMENTAL IMPLICATIONS

Geochemistry of trace elements and REE of the Quaternary sediments in the Yaoshang Formation in Weining country, Guizhou,China were analyzed. Based on the previous studies about Ostracoda and pollen, we discussed the sedimentary environmental changes through the vertical variation of elements. Our results show that the 14 trace elements (eg. Li, Ba, Sr) are well correlated. Generally, ∑REE is very high, and δCe and δEu are negative,except that Ce in the layers 7 and 11 are positive. LREE and HREE fractionation is obvious. And the chondrite normalized samples show a distribution pattern of LREE enrichment with gentle incline to the right. The parameter of elements ratio and REE are characterized by zonation.The content the 14 trace elements and Rb/Sr、Sr/Ba、Sr/Cu ratio indicate a relatively dry and hot climate in the layers of 2,6,8,10,12 of the Yaoshang Formation while the other layers formed undera colder and wetter climate. Sr/Cu changes between 1 and 5, indicating a humid subtropical plateau monsoon climate. Sr/Ba changing between 0.2~0.5 indicates that the Caohai sediment was deposiled in a freshwater enviroment, suggesting a very strong weathering of the parent nock of the Permian basalt which is high in REE content. The combination of Sr/Cu and Rb/Sr ratio values can be used as the indicator of climatic change.