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中全新世年至10年际东亚季风气候变率及其动力学机制有助于深入了解当今全球气候变暖的自然变率贡献。本文基于湖北青天洞一支石笋的铀系年龄、年纹层计数、氧同位素和微量元素测量结果,建立了中全新世5.57~4.84ka B.P.时段平均分辨率为3~4年的东亚季风气候和洞穴地点环境演变序列。石笋年纹层由冬季亮色薄层和夏季暗色厚层组成,对应冬、夏季节层的δ~(18)O和δ~(13)C正负漂移与现今冬夏降水和岩溶环境同位素值变化基本吻合。然而,元素比值(Mg/Ca和Sr/Ca)揭示了冬夏季风降水与岩溶作用的复杂响应过程。在10年际尺度上,石笋氧同位素记录了3次间隔200年左右的弱季风事件,分别发生于5.56~5.50ka B.P.,5.26~5.20ka B.P.和5.01~4.94ka B.P.,每个事件大约持续60年,反映了太阳活动周期控制季风强度变化的频率。Mg/Ca和Sr/Ca比值与季风强弱变化不存在明显的对应关系,但其功率谱具有200年和40年左右周期,说明东亚季风气候和岩溶环境过程之间既有共同的控制因素又有不同的演化机理。
The East Asian monsoon climate variability and its dynamics from mid-Holocene to 10 years contribute to a deeper understanding of the natural variability contribution of today’s global warming. Based on the uranium age, annual stratum count, oxygen isotope and trace element measurements of a stalagmite in Qingtian Cave, Hubei Province, the East Asian monsoon climate and caves with average resolution of 3-4 years in the Middle Holocene 5.57 ~ 4.84ka BP were established. Location Environmental Evolution Sequence. The stratum of the stalagmite was composed of bright winter coat and dark thick coat in summer. Corresponding to the positive and negative δδ (18) O and δ ~ (13) C shifts of winter and summer stratum, and the changes of isotope values in winter and summer precipitation and karst environment Anastomosis. However, the elemental ratios (Mg / Ca and Sr / Ca) reveal the complicated response process of winter monsoon rainfall and karstification. On the 10-year scale, the stalagmite oxygen isotope records three weak monsoon events about 200 years apart, occurring at 5.56-5.50 ka BP, 5.26-5.20 ka BP and 5.01-4.94 ka BP, respectively, each lasting for about 60 days Year, reflecting the frequency of solar-cycle-controlled monsoon intensity changes. The ratio of Mg / Ca and Sr / Ca does not have a clear correspondence with the change of the monsoon intensity, but the power spectrum has a period of 200 years and 40 years, indicating that both the East Asian monsoon climate and the karst environment process have common control factors Different evolution mechanisms.