地学前缘 ›› 2016, Vol. 23 ›› Issue (6): 268-286.DOI: 10.13745/j.esf.2016.06.019

• 综合地层学与古生物学 • 上一篇    下一篇

秦皇岛石门寨亮甲山奥陶系剖面化学地层和旋回地层研究

马坤元，李若琛，龚一鸣   

  1. 中国地质大学 生物地质与环境地质国家重点实验室; 中国地质大学(武汉) 地球科学学院, 湖北 武汉 430074
  • 收稿日期:2016-07-11 修回日期:2016-09-19 出版日期:2016-11-15 发布日期:2016-11-15
  • 通讯作者: 龚一鸣(1958—)，男，教授，长期从事地层学、古生物学和沉积地质学的科学研究和教学。E-mail：ymgong@cug.edu.cn
  • 作者简介:马坤元(1993—)，男，博士研究生，古生物学与地层学方向。E-mail：cug-mky@qq.com
  • 基金资助:

    国家自然科学基金项目(41290260，41472001)

Chemostratigraphy and cyclostratigraphy of the Ordovician Liangjiashan section from Shimenzhai of Qinhuangdao in North China.

MA Kunyuan, LI Ruochen, GONG Yiming.   

  1. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences; School of Earth Sciences, China University of Geosciences(Wuhan), Wuhan 430074, China
  • Received:2016-07-11 Revised:2016-09-19 Online:2016-11-15 Published:2016-11-15

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摘要：

根据秦皇岛石门寨亮甲山奥陶系剖面的化学地层和岩石地层特征，将亮甲山组(O1l)细分为下、中、上段。选取Fe/Ca、Ti/Ca作为古气候替代指标，开展时间序列分析。通过多窗谱法(MTM)和傅里叶变换法(FT)，从Fe/Ca、Ti/Ca比值中共提取出两个明显的米兰科维奇旋回：长偏心率405 ka和短偏心率90 ka。基于长偏心率周期建立的天文年代标尺表明，亮甲山组沉积时长为6.2 Ma，平均沉积速率为14.68 m/Ma，其中亮甲山组下段(0.00~48.00 m)和中上段(48.00~91.00 m)的沉积速率分别为12.00 m/Ma和19.55 m/Ma；马家沟组下部的沉积速率为18.00 m/Ma。奥陶纪生物大辐射可能直接导致碳酸盐生产模式由以灰泥生产为主转变为以生物碎屑生产为主，并使亮甲山组下段与中上段之交碳酸盐沉积速率大幅增加。旋回地层分析显示，早、中奥陶世之交天文轨道周期变化引起的地球气候改变可能对奥陶纪生物大辐射有重要的调控作用。

关键词: 旋回地层, 化学地层, X射线荧光光谱分析仪(XRF), 亮甲山组, 奥陶纪, 奥陶纪生物大辐射, 华北秦皇岛

Abstract:

According to the chemostratigraphy and lithostratigraphy of the Ordovician Liangjiashan section in Qinhuangdao of North China, the Liangjiashan Formation was divided into the lower, middle and upper members. We chose the Fe/Ca and Ti/Ca ratios as the paleoclimate proxies and carried out the timeseries analysis. The timeseries analysis of the Fe/Ca and Ti/Ca data was performed by means of Multi Taper Method (MTM) and Fourier Transform (FT), from which two obvious cycles were identified: long eccentricity (E) 405 ka and short eccentricity (e) 90 ka. The float point time scale (based on the long eccentricity cycle) indicates that the duration of the Liangjiashan Formation is 6.2 Ma, the mean sediment accumulation rate in the Liangjiashan Formation is 14.68 m/Ma, and the sedimentation rate of the lower member and the middleupper members are 12.00 m/Ma and 19.55 m/Ma respectively; the sedimentation rate in the Majiagou Formation is 18.00 m/Ma. The Ordovician radiation seemed to result in the changing of carbonate production from marldominated to biodetritusdominated, which accelerated the sediment accumulation rate during the transition from the lower to the middleupper members of the Liangjiashan Formation. Our cyclostratigraphical data show that the Ordovician radiation may be regulated by the earth's climate changes caused by the orbit cycle variations.

Key words: cyclostratigraphy, chemostratigraphy, X-ray fluorescence scanning analysis (XRF), Liangjiashan Formation, Ordovician, Ordovician radiation, Qinhuangdao, North China

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