Geologic evidence for chaotic behavior of the planets and its constraints on the third-order eustatic sequences at the end of the Late Paleozoic Ice Age

Integrated multi-stratigraphic study of the Coll de Terrers late Permian–Early Triassic continental succession from the Catalan Pyrenees (NE Iberian Peninsula): A geologic reference record for equatorial Pangaea

“…Consequently, a short-eccentricity origin (~100 kyr duration) may be attributed to the basic sequences while the band with periods of 8-12 m would represent the 400 kyr long eccentricity cycle. Moreover, in this context, the cyclicity with periods around 24 m might fit with the very long 1.2 Myr obliquity modulation cycle, which have already been detected in the Permian (Fang et al, 2015;Li et al, 2016). The alternative interpretation of the basic cycle as precession cycles (~21 kyr) appears less likely as the 24 m period would be difficult to fit to any orbital period despite the 8-12 m could still fit to short eccentricity.…”

Comment on “Geologic evidence for chaotic behavior of the planets and its constraints on the third-order eustatic sequences at the end of the Late Paleozoic Ice Age” by Fang, Q., Wu, H., Hinnov, L. A., Jing, X., Wang, X., & Jiang, Q. [Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 440, 15 December 2015, 848–859 (2015)]

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Available online xxxx Fang et al (2015: Geologic evidence for chaotic behavior of the planets and its constraints on the third-order eustatic sequences at the end of the Late Paleozoic Ice Age) claim to have identified a comprehensive suite of orbital periodicities (Milankovitch cycles) in a Permian succession in southern China through the use of spectral analysis. We refute their claim on the grounds that their spectral analytic methodspecifically, the estimation of significance thresholdsgreatly overestimates the significance of the periodicities.

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“…All such conclusions depend upon the validity of the spectral analytical methodology used to identify cycle periods in stratigraphic data-series. Readers of the paper by Fang et al (2015), and of numerous similar papers, should be aware of serious flaws in the statistical methodology routinely used in cyclostratigraphic research. These errors lead inevitably to large numbers of probably incorrect cycle identifications, throwing doubt on any further conclusions based on the supposed cycle periods.…”

“…These errors lead inevitably to large numbers of probably incorrect cycle identifications, throwing doubt on any further conclusions based on the supposed cycle periods. Fang et al (2015) investigated a series of 948 ARM (anhysteretic remanent magnetization) measurements taken at variable vertical spacing from a ca. 201 m-thick section through the Permian Maokou Formation in southern China.…”

“…In a previous paper (Vaughan et al, 2011) we drew attention to important errors in the statistical approach to the discrimination of (cyclic) signal from (random) noise in the periodogram approach to spectral analysis as very widely used by the cyclostratigraphy community. We are concerned that Fang et al (2015) and many others continue to disregard our demonstration that their methods are invalid.…”