| 北黄海东部坳陷始新统米兰科维奇旋回特征 |
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| 引用本文： | 吴淑玉,刘俊.北黄海东部坳陷始新统米兰科维奇旋回特征[J].地球科学,2015,40(11):1933-1944. |
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| 作者姓名： | 吴淑玉 刘俊 |
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| 作者单位： | 1.国土资源部海洋油气资源与环境地质重点实验室, 山东青岛 266071 |
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| 基金项目： | 国土资源部海洋油气资源和环境地质重点实验室基金项目MRE201318国土资源部海洋油气资源和环境地质重点实验室基金项目MRE201121国土资源部海洋油气资源和环境地质重点实验室基金项目MRE201115国家海洋局海底重点实验室基金项目KLSG1102中国地质调查项目GZH200700405国土资源部公益性行业科研专项课题201211086-09 |
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| 摘 要： | 米兰科维奇旋回是记录在沉积地层中的表现形式, 其代表的时间涵义是进行高分辨率地层划分和对比的有效手段, 从地层中揭示的米兰科维奇旋回, 可以完善地层学尤其是旋回地层学理论.以北黄海东部坳陷为研究对象, 根据J. Laskar的解决方案计算出该区始新统的米兰科维奇旋回周期为: 125 ka和99 ka的偏心率周期, 51 ka和39 ka的地轴斜率周期, 23 ka和19 ka的岁差周期.通过对3口井的GR(自然伽马)和SP(自然电位)测井曲线进行频谱分析, 发现其频谱峰值与天文周期存在着良好的对应关系, 因此可以判定该区域地层中保存着完好的米兰科维奇沉积旋回.地层旋回厚度存在13.03~15.89 m的长周期、3.70~5.21 m的中周期和2.17~2.94 m的短周期, 并由此计算地层的沉积速率为121.20~127.12 m/Ma.从隆起沿着斜坡往湖盆中心, 沉积持续时间越长且沉积厚度也越厚, 但沉积速率相对稳定.通过连续小波变换对始新统地层进行小层划分, 划分出6期沉积体, 以每个沉积体为独立窗口进行频谱分析计算出沉积的持续时间和速率, 从气候变化的影响分析每个阶段的沉积环境.从下往上层序地层E6期为低水位体系域, E5和E4为湖泊扩张体系域, E3为高位体系域, E2和E1为湖泊收缩体系域.以上方法可以证明米兰科维奇进行沉积旋回分析是一种有效的方法.
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| 关 键 词： | 北黄海东部坳陷 始新统 米兰科维奇 沉积旋回 沉积速率 沉积持续时间 地球物理. |
| 收稿时间： | 2015-03-29 |
Characteristics of Milankovitch Cycle in Eocene Formation,Eastern Depression of the North Yellow Sea Basin |
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| Abstract: | Milankovitch cycle is the manifestation of sedimentary stratigraphy recorded, its time implication is an effective means of high resolution stratigraphic division and correlation, from the reservation information of Milankovitch cycles, which enrich stratigraphic theory, especially cyclostratigraphic theory. Characteristics of Milankovitch cycle in the eastern depression of the North Yellow Sea basin are explored in this study. Major parameters of Milankovitch cycle are worked out by J. Laskar solution in the Eocene formation: the eccentricity cycle is 125 ka and 99 ka; the obliquity cycle is 51 ka and 39 ka; and the precession cycle is 23 ka and 19 ka. It is found by frequency spectrum analysis of the GR and SP well logging of three wells that the spectrum peak cycle corresponds well to its astronomy cycle, indicating well-preserved Milankoitch cycle in the formation. Stratigraphic cycle thickness is of 13.03 to 15.89 m long-cycle, 3.70 to 5.21 m mid-cycle and 2.17 to 2.94 m short-cycle, by which the formation sedimentation rate is calculated as between 121.20 to 127.12 m/Ma. The sedimentary duration is increasingly longer and the deposition thickness is increasingly thicker from uplift along the slope toward the center of the lake basin. However, the sedimentation rate is relatively stable.As to sublayer division of Encene with the continuous wavelet transform, it can be divided into six sedimentary bodies, with each body as a separate window for spectrum analysis to calculate the duration and rate of sedimentation. From the perspective of the impact of climate change on the sedimentary environment, it is concluded that, E6 period was low water system tract, E5 and E4 were lake expand system tract, E3 was highstand systerm tract, E2 and E1 were lakes contraction system tract from the bottom to top sequence stratigraphy. It is confirmed that Milankovitch cycle is an effective approach for depositional cycle analysis. |
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