关键词: 米兰科维奇旋回, 小波分析, 天文年代标尺, 高频层序, 上二叠统, 盘县

Abstract: The Upper Permian recorded the greatest mass extinction events and the most dramatic environmental changes in geological
history. Fine description of stratigraphic framework and the establishment of high-resolution stratigraphic sequence of the Upper
Permian have been the key and foundation to in-depth understanding of these events and evolutions. Based on comprehensive analyses
of well logging, core observation, and geochemical testing results, this study performs the sequence stratigraphic division of the Upper
Permian coal measures on Milankovitch cycles using wavelet analysis in Panxian, western Guizhou Province. Results show that
well-preserved Milankovitch cycles were contained in the measures. The sedimentary process of coal measures was obviously affected
by astronomical orbital period. The thickness of 16.06-17.24 m, 5.39-5.70 m, 2.11-2.15 m and 1.12-1.21 m were affected by long
eccentricity (405 ka), short eccentricity (123 ka), obliquity (44 ka) and precession (21 ka), respectively. Among the four controlling
factors, the long eccentricity had the strongest effect on the coal measures of Milankovitch cycles. A“floating”astronomical time scale
was established by filtering the long and short eccentricity cycles, which provided geo-chronological constraints on the formation and
duration of the synsedimentary volcanic event layers (known as Tonsteins). Finally, taking the long eccentricity cycles as isochronous
section and combined with the sedimentary succession and characteristics of cycle boundaries, the Upper Permian coal measures in the
study area can be divided into four third-order sequences and sixteen fourth-order sequences. These help to establish the regional
high-frequency cyclic sequence framework.

Key words: Milankovitch Cycles, wavelet analysis, astronomical time scale, high-frequency cyclic sequence, the Upper Permian, Panxian