Qaidam Basin Drilling Natural Gamma Curve Recorded Long-period Short-scale (thousands, A Hundred Years Of Class) Of Ancient Climate Change

To realize more clearly the evolution of climate and environment in the future, it is important to explore and analyze the processes and mechanism of the environment changes in the past. Due to such a high sediment rate in the Qaidam Basin, where exits long and continuous Quaternary sequence, there is a higher resolution to reconstruct the paleoclimatic and paleoenvironmental changes in the Quaternary. This dissertation addresses on the Sezhong 6 core with a length of 760m,located near the center of the Caidam Basin,where 248 samples at a vertical spacing l~3m were firstly collected systematically to analyze the content of grain size . Secondly, the typical 4 short layers are chosen, where 114 samples at an average vertical spacing 10cm were collected systematically to analyze the content of grain size ,clay mineral, radioactivity element (U, Th and K),and cite the content of the authigenic CaCOs from Chen Ye' doctor thesis.Sediment environment of the Sezhong 6 core is credible.This is the foundation of using natural gamma logging (GR) curves to establish the model of inverse of palaeoclimatic changes. On the different sediment environment in the typical 4 short layers, the correlation between the GR size and the other palaoclimatic indicators is discrepant, but many of them is close. The GR curves fluctuation on millennial or centennial scale is also significant.It is the timescale that occupies an important position in the Quaternary paleoclimatic researches. Because magnetic reversal ages have been modified several times in the past, in order to correlate with other global records, a new orbital tuning scale of Qaidam Basin is needed. The timescale in this paper is up to datings from Yuan Linwang ' doctor thesis. Using a interpolation at spacing lOOa to gain a centennial scale time sequence.The long period of millennial or centennial scale variations of paleoclimate is a insufficient field. Since the GR fluctuation and the other palaoclimatic indicators has good matching correlation on the millennial or centennial scale, we can use the GR curves to discuss the millennial or centennial scale inverse of palaeoclimate changes, we gain the average 600-800 cycles by analyzing synthetically the GR and other palaoclimatic indicators curves fluctuation in the typical 4 short layers. And the 1467 cycles is validated by the stat of lithology gyration and sedimentary facies. At the same time,there are a series of cycles for the age interval 1.35Ma B P to 2.24 Ma B P by spectrum analysis with the numerical curves of geophysical Gamma logging of the core. Many of these cycles can also be found out in palaoclimatic indicators of the other region, which gives us strong proof.