Luminescence dating of Old Red Sand in Yancuo,Jinjiang,Fujian and its environmental significance
As one of the important materials of global climate change research,the Old Red Sand can effective-ly reflect the coastal geomorphological process and climate evolution background since the late Pleistocene.Lim-ited by no reliable dating methods,the formation age and climatic background of Old Red Sand in South China have not been well solved.For that matter,this study selected the section of Yancuo Old Red Sand located in Jin-jiang,Fujian Province.In the laboratory,the single aliquot regenerative-dose method of medium-particle quartz was used for luminescence age measurement,and the samples were tested for grain sizes and geochemical ele-ments.The influence of dispersion coefficient and chemical weathering index CIA on the reliability of Old Red Sand dating results was discussed.At the same time,through the statistical analysis of probability density of some reported Old Red Sand age data in South China,the formation of Old Red Sand in South China and its en-vironmental background were discussed.The results showed that:(1)Yancuo profile(YCR)was a typical aeoli-an sand dune,with good sorting,and the whole was mainly medium sand and fine sand.(2)The sedimentation of Old Red Sand in Yancuo was mainly formed during the period of 132.85-37.22 ka,among which,in the MIS5 and MIS4 stages,the sand dunes may be in the state of activation-deposition-reactivation,and the OSL signal is not well preserved,so it appears the illusion of"sedimentary disconnection".And the MIS3 stage corre-sponds to the regressive period,the sedimentation rate of aeolian sand is relatively fast,and the weathering de-gree is strong in the warm and humid climate environment.(3)Affected by sea level change and winter wind in-tensity,Old Red Sand deposition may occurred in both high sea level and low sea level,but its sedimentation stages are mainly occurred in 80-30 ka,corresponding to MIS4 and MIS3 stages.The sedimentary process of Old Red Sand mainly occurred in the regressive stage,when the sea level is neither high nor low.Too high or too low sea level will affect the provenance range,and then affect the accumulation process of Old Red Sand.
South China coastFujianOld Red Sandoptically stimulated luminescence
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NSTL
万方数据
