构造动力学研究是分析区域构造、沉积演化、岩浆活动及矿产分布的重要前提,前人研究证实自太平洋板块形成以来中国东部构造动力学背景发生了多次转变,但对于具体的转换机制还缺乏深入研究。为此,首先基于对近年来发表的同位素年龄和古地磁数据的系统收集和整理,对太平洋板块形成以来围限中国东部的太平洋板块、印度板块和菲律宾海板块等的形成年代、漂移轨迹和速率变化规律进行了详细梳理。然后依据这3大板块及其周缘板块的运动学规律,结合区域上的构造变形特征,将太平洋板块形成以来的中国东部构造动力学背景划分为:中侏罗世—早白垩世((175～170)～(145±5),(145±5)～125和125～95 Ma BP)、晚白垩世—古近纪(95～80,80～43和43～23 Ma BP)和新近纪—第四纪(23～10 Ma BP和10 Ma BP至今)等多个阶段。指出中国东部中侏罗世—早白垩世为压扭性背景,晚白垩世—古近纪则转为伸展拉张背景,到了新近纪—第四纪又转变为挤压背景,并对这3大阶段不同时期构造动力学背景作了进一步的论述。
The Hilbert-Huang transform（HHT） is a new analysis method suitable for nonlinear and non-stationary signals.It is very appropriate to seismic signals because they show both non-stationary and nonlinear characteristics.We first introduce the realization of HHT empirical mode decomposition（EMD） and then comparatively analyze three instantaneous frequency algorithms based on intrinsic mode functions（IMF） resulting from EMD,of which one uses the average instantaneous frequency of two sample intervals having higher resolution which can determine that the signal frequency components change with time.The method is used with 3-D poststack migrated seismic data of marine carbonate strata in southern China to effectively extract the three instantaneous attributes.The instantaneous phase attributes of the second intrinsic mode functions（IMF2） better describe the reef facies of the platform margin and the IMF2 instantaneous frequency attribute has better zoning.Combining analysis of the three IMF2 instantaneous seismic attributes and drilling data can identify the distribution of sedimentary facies well.
Seismic attributes have been widely used in oil and gas exploration and development. However, owing to the complexity of seismic wave propagation in subsurface media, the limitations of the seismic data acquisition system, and noise interference, seismic attributes for seismic data interpretation have uncertainties. Especially, the antinoise ability of seismic attributes directly affects the reliability of seismic interpretations. Gray system theory is used in time series to minimize data randomness and increase data regularity. Detrended fluctuation analysis （DFA） can effectively reduce extrinsic data tendencies. In this study, by combining gray system theory and DFA, we propose a new method called gray detrended fluctuation analysis （GDFA） for calculating the fractal scaling exponent. We consider nonlinear time series generated by the Weierstrass function and add random noise to actual seismic data. Moreover, we discuss the antinoise ability of the fractal scaling exponent based on GDFA. The results suggest that the fractal scaling exponent calculated using the proposed method has good antinoise ability. We apply the proposed method to 3D poststack migration seismic data from southern China and compare fractal scaling exponents calculated using DFA and GDFA. The results suggest that the use of the GDFA-calculated fractal scaling exponent as a seismic attribute can match the known distribution of sedimentary facies.
