重庆金佛山地区全新世石笋记录研究

发布时间：2018-03-23 03:31

本文选题：石笋　切入点：全新世　出处：《西南大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,全球气候明显变暖,极端天气加剧,气候变化研究在世界范围内展开,古气候作为现代和未来气候环境变化的重要参照系,已成为当今国际上地学领域的一大研究热点。全新世是地质时代的最新阶段,是人类出现与人类文明高度发展的时期,人类当前社会的一切繁荣、富强、发展、进步都发生在全新世,因此全新世的研究对人类意义重大。已有研究显示,亚洲季风区内全新世气候变化并不稳定,内部存在弱季风事件,但这些研究大多侧重于对季风整体变化趋势及其驱动机制进行探讨,弱季风事件也主要探讨4.2ka BP和8.2ka BP事件,对于其他高分辨率弱季风事件及其机制研究探讨很少。高分辨率石笋记录是古气候重建的重要地质载体,本文以重庆金佛山黑风洞所在区域为研究区,利用黑风洞HF01石笋测试所得的31个230Th数据建立精确年代模式,与石笋δ13C、δ18O和灰度数据建立全新世时段高分辨率石笋记录,还结合其他地质记录探讨全新世时期的气候变化规律及弱季风事件,并通过与北半球夏季33℃太阳辐射能量变化曲线对比及功率谱和小波分析,探讨全新世气候冷暖波动及亚洲季风变化的可能驱动机制,以及与北大西洋气候的相关关系。得出如下结论：(1)黑风洞石笋HF01全新世高分辨率δ18O记录发现：① 11.5ka BP～10.4ka BP,氧同位素值的波动范围为-8.43～-9.22‰,平均值-8.88‰,与湖北三宝洞SB43、贵州董哥洞D4、阿曼Q5等石笋δ18O记录表现出的逐渐偏负的变化趋势不同,HF01石笋的δ18O在这一时段变化比较稳定,并无明显偏负趋势,可能是由于受到区域性因素的影响,导致气候响应机制的不同；② 10.4ka BP～5.7ka BP这一阶段,δ18O明显偏负,这一时期该地气候相当温暖湿润,是全新世季风最强时期,响应于太阳辐射的高值,该时间段内季风总体平稳但存在一些弱季风事件,最为强烈的就是8.2ka BP,表现出双峰结构。③ 5.7ka BP～0.5ka BP,δ18O值波动范围介于-6.64～-9.11‰,平均值为-7.72‰,石笋δ18O从5.7kaBP开始的逐渐偏正到后来的持续偏正,是整个全新世δ18O最为偏正的时期,根据变化幅度的不同,可以划分为5.7ka BP～4.2ka BP石笋δ18O迅速偏正和4.2ka BP～0.5ka BP石笋δ18O缓慢偏正两个阶段,季风演化表现为持续衰退到4.2ka BP后的缓慢衰减。这两个时期的分界线4.2ka BP事件是发生在全新世中后期最重要、影响最大的气候突变事件,其范围波及整个北半球。(2)石笋氧碳同位素、灰度与北大西洋气候记录对比中,石笋δ13C和灰度在冷期表现出与北大西洋气候记录振荡形式上的一致性,表明在百年—千年事件尺度上主要受控于当地温度变化,石笋δ13C和灰度对温度的响应模式为：温度增高,地表植被生物量增加,土壤微生物量上限提高,土壤CO2产率增高,导致土壤CO2的δ13C值偏负,同时,洞穴通风作用减弱,使石笋的δ13C值偏负；相应的土壤中有机质含量也增加,洞穴滴水中的有机质也随之增多,灰度值升高；反之,温度降低导致地表生物量减少,洞穴通风作用加强,石笋的δ13C值偏正,土壤中有机质含量也减少,灰度值降低。HF01石笋δ13C和灰度都很好的记录了全新世弱季风事件,与冰芯、黄土、湖泊、孢粉等考古史料所得的结论有很好的对应关系。并指出虽然石笋δ13C和灰度有良好的对应关系,也都能够反映北大西洋全新世气候变化,但还是有所差别：石笋灰度单独的记录了早全新世11.2ka BP冷事件,与北大西洋Bond 8事件在误差范围内一致,也与中国西南地区红原泥炭纤维素δ13C记录很好的对应,而石笋δ13C对这一冷事件反映不甚明显；石笋δ13C和灰度对Bond 6事件响应时间不一致；石笋δ13C和灰度对2.8ka事件反映强度差别也比较大。最后说明二者出现差异的可能原因是由于测定介质来源的不同(石笋δ13C主要来源于土壤中CO2的δ13C；石笋灰度扫描光线不同主要是滴水中的有机质含量不同)和测定方式(石笋δ13C是仪器分析；灰度是扫描仪扫描结果)不同导致的。(3)石笋HF01碳氧同位素与北半球夏季33°太阳辐射能量变化曲线基本一致,灰度的功率谱分析显示出与太阳活动相对应的周期,说明该地季风气候演化主要是受轨道诱导的太阳辐射能量的宏观调控作用。同时,Matlab也分析出除太阳辐射影响之外,北大西洋气候也控制着低纬季风的变化,尤其是在百年—千年时间尺度上,高纬地区的气候变化也可能影响着亚洲季风的变化过程,季风区内气候和高纬地区气候变化遥相关。
[Abstract]:In recent years, the global climate warming, extreme weather and climate change intensifies, research carried out in the world, the ancient climate as important reference for modern and future climate change, has become a research hotspot in the field of international geoscience. The Holocene is the new stage of geological era, and is the height of the development of human the period of human civilization, all the current human society prosperity, prosperity, development and progress have occurred in the Holocene, so the study of the Holocene is significant to the human race. It has been shown that the Asian monsoon region during the Holocene climate change is not stable, the internal weak monsoon events, but most of these studies focus on the whole monsoon the change trend and driving mechanism, weak monsoon events also focused on 4.2ka BP and 8.2ka BP events for other monsoon events and mechanism research of high resolution weak little. High resolution stalagmite records is an important carrier of geological reconstruction of paleoclimate, the Jinfo Mountain in Chongqing Batu Caves area as the study area, using 31 230Th HF01 data of Batu Caves stalagmite test obtained establish accurate age model, and the stalagmite Delta 13C Delta 18O, and establish the new world time gray data of high resolution stalagmite record, also combined with other geological to record the climate changes of Holocene and weak monsoon events, and through the northern hemisphere summer and 33 degrees of solar radiation energy curves and the comparison of power spectrum and wavelet analysis, explore the Holocene climate fluctuation and Asian monsoon changes may be driving mechanism, and their correlation with North Atlantic climate. The main conclusions are as follows: (1) Batu Caves stalagmite HF01 high resolution Holocene Delta 18O records found: 1. 11.5ka BP to 10.4ka BP, the fluctuation range of oxygen isotope values for -8.43 ~ -9.22%, The average value of -8.88%, and the three treasures of Hubei Dong SB43, Guizhou Dongge cave D4, changes gradually partial negative trend records show stalagmite Delta 18O Oman Q5, Delta 18O HF01 from changes in this period is relatively stable, there is no obvious negative trend may be due to regional factors. The response mechanism of different climate; this phase II 10.4ka BP ~ 5.7ka BP, Delta 18O was negative, in this period, the climate is warm and humid Holocene monsoon period is the strongest response, high value of solar radiation, the monsoon period is generally stable but there are some weak monsoon events, the most strong is 8.2ka BP, showing the structure of Shuangfeng. The 5.7ka BP ~ 0.5ka BP, 18O values range from -6.64 to -9.11%, with an average of -7.72%, 8 18O stalagmite 5.7kaBP from start to gradually biased to the later continuous partial, a Holocene Delta 18O For partial period, according to the variation of the different, can be divided into 5.7ka BP ~ 4.2ka BP 18O quickly pianzheng and stalagmite Delta 4.2ka BP ~ 0.5ka BP 8 18O pianzheng stalagmite slow two stages, monsoon evolution showed continued decline to 4.2ka BP after a slow decay. The two stages of the demarcation line of 4.2ka the BP event occurred in the late Holocene in the most important event, mutations affecting the largest climate, its range spread throughout the northern hemisphere. (2) stalagmite oxygen and carbon isotope, gray and North Atlantic climate record comparison, stalagmite Delta 13C and gray in the cold period showed consistency with the North Atlantic Oscillation on climate records and that is mainly controlled in a hundred years - Millennium event scale on the local temperature response model of delta 13C and gray stalagmite on temperature: the temperature increases, the surface vegetation biomass increased, soil microbial biomass increased soil CO2 yield limit increase, In Delta 13C soil CO2 value is negative, at the same time, weaken the cave ventilation effect, the delta 13C values of stalagmite negative; also increase the content of organic matter of the soil, the organic matter in the cave drip also increases the gray value increased; on the contrary, the temperature drop in the ground biomass reduction, strengthening the cave ventilation effect of delta 13C stalagmite value partial positive, but also reduce the content of organic matter in soil, gray value reduced.HF01 from Delta 13C and gray are very good record of Holocene weak monsoon events, and ice core, loess, lake, there is a good correlation between the sporopollen archaeological historical conclusion and pointed out that although there are. Good correspondence between 13C and 8 stalagmite gray, also can reflect the North Atlantic Holocene climate changes, but still has a difference: separate records of stalagmite gray early Holocene 11.2ka BP cold events, and the events in the North Atlantic Bond 8 error range consistent, Also with the corresponding Hongyuan peat cellulose Delta 13C has a very good record of Southwest Chinese, and delta 13C of the stalagmite reflect the cold event is not very obvious; stalagmite Delta 13C and Bond 6 on the gray incident response time inconsistency; stalagmite Delta 13C and 2.8ka events reflect on gray intensity difference is relatively large. The description of the two possible reason for the difference is determined by different media sources (from Delta 13C mainly came from the soil in the CO2 Delta 13C; gray scale scanning light is different from the content of organic matter in different water) and methods (stalagmite Delta 13C is the instrument analysis; gray scale scanning is different. (results) 3) HF01 stalagmite carbon and oxygen isotopes and the northern hemisphere summer 33 degree solar radiation energy curve is consistent, gray power spectrum analysis shows that periodic correspond to the solar activity, shows the evolution of the monsoon climate is mainly affected by the The role of macro-control track induced by solar radiation energy. At the same time, Matlab also analyzed besides the influence of solar radiation, the North Atlantic climate change also controls the low latitude monsoon, especially in the Centennial millennial time scale, climate change in high latitudes may also affect the change process of Asian monsoon, monsoon region in the high latitude climate and climate change teleconnection.

【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P534.632;P532

【参考文献】