长江三角洲上新世以来磁性地层及天文调谐年代标尺
发布时间：2018-10-24 10:32
【摘要】：长江三角洲地区的磁性地层认识存在很大不确定性.为建立一个可靠的年代标尺,为区内沉积环境和气候演化研究提供约束,在年代地层和磁性地层基础上,以频率磁化率为信号源、ETP为靶曲线,通过轨道调谐方法对区内LZK1孔开展了天文年代标尺研究,建立了年代序列框架.结果显示,M/B界线埋深约为143.0m、Ga/M界线埋深约为219.0m、Gi/Ga界线埋深约为296.6m.受气候和沉积环境控制,沉积旋回特征清楚,沉积速率具有明显的阶段性.调谐后的频率磁化率显示了显著的125ka、96ka、41ka、23ka、22ka、18ka等轨道周期,并在轨道周期上与ETP曲线高度相关,相关性超过了95%检验标准.100ka、41ka和23ka周期的带通滤波曲线与偏心率、斜率和岁差在振幅和相位上吻合较好,但局部时间段有差异,可能与低沉积速率、沉积速率突变或短时间尺度的地层缺失等因素有关.研究表明,在具有短暂沉积缺失的持续沉降区域,只要保证样品分辨率,可以通过轨道调谐方法建立可靠的年代框架.
[Abstract]:There is great uncertainty in the understanding of magnetic strata in the Yangtze River Delta region. In order to establish a reliable chronological scale and provide constraints for the study of sedimentary environment and climate evolution in the region, based on chronostratigraphy and magnetic strata, frequency susceptibility is used as signal source and ETP as target curve. The astronomical chronological scale of LZK1 holes in the region was studied by orbital tuning method, and the chronological sequence framework was established. The results show that the buried depth of the M / B boundary is about 143.0 m / m and the depth of the Ga / Ga line is about 219.0mGi / Ga boundary is about 296.6m. Controlled by climate and sedimentary environment, the characteristics of sedimentary cycle are clear, and the deposition rate has obvious stages. The frequency magnetization after tuning shows a remarkable orbital period of 125ka / 96ka / 41ka/ 23ka/ 22ka/ 18ka, and is highly correlated with the ETP curve in the orbital period, which exceeds the 95% test standard. The bandpass filtering curve and eccentricity of the 100ka / 41ka and 23ka period are obtained. The slope and precession agree well with each other in amplitude and phase, but there are differences in local time periods, which may be related to the low deposition rate, the sudden change of deposition rate or the lack of strata on a short time scale. It is shown that in the area of continuous subsidence with transient sedimentary absence, a reliable chronological framework can be established by orbital tuning method as long as the resolution of the sample is ensured.
【作者单位】： 中国地质大学地球科学学院;上海市地质调查研究院;中国科学院地球环境研究所;江苏省地质调查研究院;
【基金】：基金项目:长江三角洲海岸带综合地质调查与监测(No.GZH201200506) 上海区域地质调查片区总结与服务产品开发(No.DD20160345-07)
【分类号】：P539.3
，
本文编号：2291135
[Abstract]:There is great uncertainty in the understanding of magnetic strata in the Yangtze River Delta region. In order to establish a reliable chronological scale and provide constraints for the study of sedimentary environment and climate evolution in the region, based on chronostratigraphy and magnetic strata, frequency susceptibility is used as signal source and ETP as target curve. The astronomical chronological scale of LZK1 holes in the region was studied by orbital tuning method, and the chronological sequence framework was established. The results show that the buried depth of the M / B boundary is about 143.0 m / m and the depth of the Ga / Ga line is about 219.0mGi / Ga boundary is about 296.6m. Controlled by climate and sedimentary environment, the characteristics of sedimentary cycle are clear, and the deposition rate has obvious stages. The frequency magnetization after tuning shows a remarkable orbital period of 125ka / 96ka / 41ka/ 23ka/ 22ka/ 18ka, and is highly correlated with the ETP curve in the orbital period, which exceeds the 95% test standard. The bandpass filtering curve and eccentricity of the 100ka / 41ka and 23ka period are obtained. The slope and precession agree well with each other in amplitude and phase, but there are differences in local time periods, which may be related to the low deposition rate, the sudden change of deposition rate or the lack of strata on a short time scale. It is shown that in the area of continuous subsidence with transient sedimentary absence, a reliable chronological framework can be established by orbital tuning method as long as the resolution of the sample is ensured.
【作者单位】： 中国地质大学地球科学学院;上海市地质调查研究院;中国科学院地球环境研究所;江苏省地质调查研究院;
【基金】：基金项目:长江三角洲海岸带综合地质调查与监测(No.GZH201200506) 上海区域地质调查片区总结与服务产品开发(No.DD20160345-07)
【分类号】：P539.3
，
本文编号：2291135
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