Chronology Of Tamarix Cone Sedimentary Veins And Its Application

There are many ways to restore the paleoenvironment, but there are few of datingmaterials and paleoenvironment information carriers in the desert region where the climate isextremely arid and the activity of wind is violent. Therefore it still exist many difficulties inestablishing the high-resolution chronology in environmental change. Tamarix cones providea new method to reconstruct the paleoenvironment of the desert region both fromhigh-resolution dating and paleoenvironment information indication for its unique laminatedstructure. However, the dating research of the sedimentary veins which are not annual layer isstill almost in blank. This paper systematically discusses the dating of the sedimentary veinsof Tamarix cone and the optimal means of dating in different circumstances. Besides, basedon the sedimentation rate changes in time and space and the development status ofsedimentary veins, this paper explores the relationship between Tamarix cone and itssedimentary environment.The main conclusions of this paper are as follows:(1) The sedimentary veins which is discernible and deposited continuously is annuallayer, a reliable natural timer, an effective means of dating. The high-resolution time seriescan be formed by studying the Tamarix cone chronology.(2) The dating of the Tamarix cone whose sedimentary veins aren’t distinct is proper touse multi-means such as210Pbex dating、137Cs dating and14C dating rather than vein dating.Multi-means can validate one another by comparative analysis, which is the prerequisite andguarantee to obtain accurate dating results.(3) The dating results of210Pbex CIC model are basically agree with137Cs dating resultsand on a century time scale, the dating significance of this two kinds of nuclides in Tamarixcone is evident.14C dating and OSL dating are not suitable for the dating of the youngerTamarix cone sedimentary veins.(4) Tamarix cones in sampling sites are formed under different sedimentarycircumstances. The sedimentation rate of Tamarix cone is different from place to place andperiod to period. The difference of the sedimentation rate is the result of long-term effects of multiple factors. In southern marginal zone of the Taklimakan desert，the sedimentation rateof Tamarix cone shows a increasing trend from the fringe of desert to the fringe of oasis.Water condition is the main reason for the difference of average sedimentation rate.(5) The clarity of the sedimentary veins of Tamarix cone in sampling sites is L>A>B>C.Only the sedimentary veins of Tamarix cone are discernible and deposited continuously canthey use as vein dating directly, otherwise they need to rely on other means of dating tovalidate and supplement one another. Only under relatively stable sedimentary environmentlike this: a certain distance away from the oasis and the interference of all kinds of natural andman-made factors, with a certain wind speed, the proper blow sand and water condition, can itdevelop the distinct sedimentary veins.