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

Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859

Contents lists available at ScienceDirect

Palaeogeography, Palaeoclimatology, Palaeoecology

journal homepage: www.elsevier.com/locate/palaeo

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

Qiang Fang a,b,⁎,HuaichunWua,c,⁎, Linda A. Hinnov d,XiuchunJinga,b, Xunlian Wang a,b,QingchunJiange a State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China b School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China c School of Ocean Sciences, China University of Geosciences, Beijing 100083, China d Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, Fairfax, VA 22030, USA e PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China article info abstract

Article history: High-resolution (948 samples) measurements of anhysteretic remanent magnetization (ARM) were performed on Received 21 January 2015 the ~200 m thick Early–Middle Permian Maokou Formation of the Shangsi section, South China. The ARM variations Received in revised form 27 September 2015 arequasi-periodicandthewavelengthsofsignificant cycles collectively present a ratio of 20:5:2:1 throughout the Accepted 8 October 2015 formation, corresponding to long orbital eccentricity, short orbital eccentricity, obliquity, and precession cycles. A Available online 28 October 2015 strong obliquity (44 and 33 kyr) signal suggests that waning and waxing of the ice sheet in eastern Australia at theendoftheLatePaleozoicIceAge(LPIA)exertedasignificant influence on global climate and sea level. A “float- Keywords: ” Milankovitch cycles ing astronomical time scale (ATS) is developed using the 405 kyr orbital eccentricity cycle as an astronomical cal- Long-period astronomical forcing ibration target. This results in estimation of the Roadian and Wordian stages duration as 3.7 ± 0.4 myr and 2.9 ± Third-order eustatic sequence 0.4 myr, respectively. Prominent ~2 myr cycles likely originated from Earth and Mars secular frequencies g4–g3,

Late Paleozoic Ice Age and ~1 myr cycles from s4–s3. These periodicities are shorter than those observed in the Cenozoic Era, which may Maokou Formation be due to the chaotic behavior of the planets, but still reﬂecting 2:1 secular resonance between Earth and Mars. South China Third-order eustatic sequences are linked to the s4–s3 obliquity term, which suggests a glacioeustatic controlling mechanism during this transitional stage from Paleozoic icehouse to Mesozoic greenhouse. © 2015 Elsevier B.V. All rights reserved.

1. Introduction distribution of incoming solar radiation over seasons and latitudes (e.g., Hinnov, 2013). Variations in Earth's astronomical parameters The Middle Permian Epoch is a key interval in the Paleozoic Era. It is have been proven to be a significant driver of paleoclimate change in characterized by the end-Guadalupian mass extinction (Stanley and the Cenozoic and Mesozoic eras (e.g., Hinnov and Hilgen, 2012), recur- Yang, 1994), the lowest sea level (Haq and Schutter, 2008)and rent biotic events (e.g., van Dam et al., 2006), ice sheet development 87Sr/86Sr ratio (McArthur et al., 2012) in the Phanerozoic, the Emeishan (e.g., Pälike et al., 2006), and third-order sea-level sequences volcanism (Zhong et al., 2014) and the Illawarra Reversal (Chen et al., (e.g., Lourens and Hilgen, 1997; Boulila et al., 2011). Amplitude modula- 1994). A precise time scale plays a crucial role in understanding these tions in the orbital eccentricity (~2.4 myr) and obliquity (~1.2 myr) geological events. However, the Geologic Time Scale 2012 (GTS2012) originating from the secular frequencies of Earth and Mars are theoret- employs only a single radioisotopic date for Middle Permian geochro- ically unstable (Laskar et al., 2004, 2011), as indicated by evidence in nology (Henderson et al., 2012), which results in a poorly constrained Mesozoic strata (e.g., Olsen and Kent, 1999; Ikeda et al., 2010; Hüsing time scale for the interval. Astrochronologic interpretation from et al., 2011). However, analogous long-period modulations have not cyclostratigraphy can result in significant refinements of the Paleozoic yet been widely reported in the Paleozoic Era (Giles, 2009; De time scale (e.g., De Vleeschouwer et al., 2012, 2013; Wu et al., 2013a). Vleeschouwer et al., 2013), and their impacts on climate and sea-level Earth's astronomical parameters (eccentricity, obliquity, precession) change have only begun to be addressed (e.g., De Vleeschouwer et al., play an important role in paleoclimate change by changing the 2014a). The Late Paleozoic Ice Age (LPIA) is characterized by ice volume expansion on the Gondwana continent, and was comparable to the size of ⁎ Corresponding authors at: State Key Laboratory of Biogeology and Environmental the Pleistocene ice age (Chen et al., 2013). The main glaciation of the Geology, China University of Geosciences, Beijing 100083, China. Tel.: +86 13811586924. E-mail addresses: [email protected] (Q. Fang), [email protected] LPIA began in western South America during the Viséan age and (H. Wu). reached its acme during the Asselian–Sakmarian (Isbell et al., 2003;

Zeng et al., 2012). Subsequently, the ice sheet broke up into pieces stacking of Late Permian to Early Triassic strata has been interpreted before finally vanishing during the earliest Late Permian in eastern as evidence for Milankovitch cycles (e.g., Wu et al., 2012, 2013a). Australia (Fielding et al., 2008a,b). The waning and waxing of glaciers Additionally, well-exposed Middle Permian outcrops in South China during the LPIA drove large global sea-level fluctuations (e.g., Giles, provide the means for investigating a wide range of scales of 2009; Davydov et al., 2010). When the high-latitude regions were paleoclimate change at the end of the LPIA. In this study, we performed partially covered by ices in the Cenozoic Era, the sensitive nature of cyclostratigraphic analysis of the Maokou Formation at Shangsi, South ice-sheets to the changes in insolation was enhanced (Zachos et al., China (Fig. 1) with the following objectives: (1) to establish a “floating” 2001a). Likewise, the fragmented ice sheet at the end of the LPIA was astronomical time scale (ATS) with interpreted 405 kyr orbital eccen- more sensitive to astronomical forcing (Horton and Poulsen, 2009) tricity cycles; (2) to estimate the timing and durations of conodont and produced obvious glacioeustatic signals in the low-latitudes zones; (3) to investigate the long-period behavior of the Earth's orbital (e.g., Fielding et al., 2008b). Third-order eustatic sequences were astro- parameters; and (4) to discuss the possible controlling mechanisms of nomically controlled during the Cenozoic icehouse and Mesozoic green- the third-order eustatic sequences during this transitional interval house (Boulila et al., 2011). The end of the LPIA, as a transition from from icehouse to greenhouse. Paleozoic icehouse to Mesozoic greenhouse, provides an excellent ar- chive for investigating the astro-climatic forcing of third-order eustatic 2. Geological setting and previous work sequences during the LPIA deglaciation. Haq and Schutter (2008) reported nine third-order eustatic sequences during late Kungurian to At the end of the LPIA, the South China Block was an isolated island early Capitanian (~11 myr) seemingly associated with long-term obliq- with the Paleotethys Sea to the west and the Panthalassa Ocean to the uity, but their origin remains unclear. east (Fig. 1a; Scotese and Langford, 1995; Angiolini et al., 2013). Shallow Astronomically forced Permian paleoclimate changes have been marine fossiliferous carbonate is widespread on the South China Block documented previously in sedimentary records of Middle Permian age (Fig. 1b; Wang et al., 1994; Feng et al., 1996). The Shangsi section (Ellwood et al., 2013; Yao et al., 2015). In South China, the hierarchical (Fig. 1b; 32°20′ N, 105°28′ E) is located in the northeastern part of the

102˚ 106˚ 110˚ 114˚ (a) (b) Shangsi Guangyuan

Chengdu a 30˚ North Yangtze Wuhan South China Basin Pangae Upper Yangtze Deep ramp Platform Ice mess Jiangnan Guiyang 26˚ Basin

(m) P 100 Guadalupian P

t P

e Permian

D Maokou Formation 50 /kg)

2 5 Am

0 -6 Maokou Formation 2.5 10 × Cisuralian Lopingian 0 -50 190 191 192 193 194195 196 197 198

Chihsia Formation Chihsia Formation

ARM ( Depth (m)

Fig. 1. (a) The Guadalupian global paleogeography. The geographic base map is modified from Angiolini et al. (2013). The location, size and, shape of the ice sheet are from Isbell et al. (2012). (b) Guadalupian paleogeography of South China, modified from Feng et al. (1996). The red star marks the location of the Shangsi section. (c) Stratigraphic division and lithological features of the bottom and top boundaries of the Maokou Formation. The stratigraphic scale is modified from Yan et al. (2008), and the chronostratigraphic division is based on conodont biostratigraphy (Fang et al., 2012). (d) The relationship between lithological cycles and ARM data of the upper Maokou Formation. The siliciclastic beds have higher ARM values than the limestones. The blue line is the interpreted 100 kyr short eccentricity extracted by Gaussian band-pass filters with a passband of 0.552 ± 0.08 cycles/m. 850 Q. Fang et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859

South China Block, and it belongs to the south flank of the Longmenshan samples were crushed, placed in standard paleomagnetic cubic boxes, Indosinian Folded Zone of the Qinling Folded System. It was a candidate and weighed. The ARM was acquired by applying a peak alternating section for the Global Stratotype Section and Point (GSSP) of the field of 0.1 T and a bias field of 50 μT on the D-2000 AF demagnetizer, Permian–Triassic Boundary (Lai et al., 1996). and the remanence intensity measurements were completed on a JR6 The Shangsi section is well exposed, structurally simple, and spinner magnetometer in a magnetically shielded room. The ARM composed of carbonate-rich sedimentary rocks. Stratigraphically, data are mass normalized. the Maokou Formation conformably overlies the Chihsia Formation and is unconformably overlain by the Wangpo Bed, the lowest part 3.2. Cyclostratigraphic analysis of the Wuchiaping Formation (Fig. 1c). The Maokou Formation is dominated by limestone, sepiolite-bearing limestone, limestone The ARM stratigraphic series was linearly interpolated to a uniform with chert nodules, and a few thin beds of mudstone or chert in 15 cm spacing and log-transformed to harmonize fluctuations (Wu fi the upper part (Fig. 1d). The precise de nition of the Maokou For- et al., 2012; Hinnov et al., 2013) (the log-transformed ARM series is mation is still under discussion. Yan et al. (2008) suggested that shown in Figs. 7 and 8). A 7% weighted average curve (Cleveland, sepiolite-bearing limestone is an important indicator of the Chihsia 1979) was calculated and subtracted using Kaleidagraph to remove Formation. However, at some sections in northeastern Sichuan, the the irregular long-term trend. Spectral analysis was carried out with sepiolite-bearing limestone extends into the uppermost the multitaper method (Thomson, 1982), as implemented in the SSA- Guadalupian Stage. Thus, in some cases this proposal assigns only a MTM Toolkit 4.4 (Ghil et al., 2002), with conventional red noise estima- few meters for the Maokou Formation, but hundreds of meters to tion. Filtering was carried out in AnalySeries 2.0.4.2 (Paillard et al., the Chihsia Formation. We adopted the original proposal that the 1996) using the Gauss algorithm to extract specific frequency intervals. boundary between the Maokou Formation and Chihsia Formation FFT spectrogram analysis (Kodama and Hinnov, 2014)wasusedtoiden- occurs at the point where light colored dolomite changes to lime- tify frequency changes along the section. stone (Geological Bureau of Sichuan Province (GBSP), 1966). Due to the absence of an explicit astronomical model for Paleozoic Biostratigraphic constraints for the Maokou Formation are mainly astrochronology and considering the robustness of the long orbital ec- fi from conodont records. The horizons of rst appearance of Jinogondolella centricity cycle, the astronomical calibration was conducted with nankingensis, Jinogondolella aserrata and Jinogondolella postserrata have interpreted 405 kyr cycles. A sinusoid with a period of 1/405 cycles/kyr fi been identi ed by Sun et al. (2008) and Fang et al. (2012). The local was constructed as a target curve. The filtered 405 kyr cycles in the sea-level curve and sequence stratigraphy have been studied using sed- ARM series were calibrated to this target curve using AnalySeries imentologic facies analysis and oxygen isotope data (Fig. 2; Xie et al., 2.0.4.2 (Paillard et al., 1996) to convert the ARM series from the strati- 2008; Li, 2009). graphic to time domain. Wavelet analysis (Torrence and Compo, 1998) The Guadalupian (Middle Permian) includes the Roadian, Wordian, was applied to identify the very low frequency variations in the astro- fi and Capitanian stages. The bases of these stages are de ned by the nomically calibrated ARM series. To assess the structure of the long- fi rst appearance of J. nankingensis, J. aserrata,andJ. postserrata and are term periodicities, amplitude modulation (AM) analysis was applied to dated as 272.3 ± 0.5 Ma, 268.8 ± 0.5 Ma, and 265.1 ± 0.4 Ma the astronomically calibrated ARM series as follows: (1) the calibrated (Gradstein et al., 2012). The time scale for the Permian is based on con- ARM series was band-pass filtered to isolate the interpreted eccentricity – ventional age depth modeling; however, this model produces overly and obliquity signals; (2) the AM curves were extracted using the Hilbert fi optimistic con dence intervals (De Vleeschouwer and Parnell, 2014). transform (e.g., Hinnov, 2000); and (3) the extracted AM curves were This problem is quite serious for the Middle Permian, where only one ra- spectrally analyzed using AnalySeries with MTM amplitude spectral dioisotopic date was used (Henderson et al., 2012). analysis. Coherency analysis was conducted using Matlab scripts from Huybers and Denton (2008).

3. Methods 4. Results 3.1. Sampling and measurements 4.1. The ARM measurements To acquire the temporal resolution needed for detecting Milankovitch cycles, high-resolution sampling is essential. The sampling ARM is less sensitive to carbonate concentration than magnetic strategy of the Maokou Formation was chosen based on the estimated susceptibility (MS), thus it is suitable for the paleoclimatic analysis of accumulation rates in different sedimentary facies. From the lower carbonate rocks (Latta et al., 2006). The ARM associates with the fi b μ part of the Maokou Formation (−0.75–173.47 m), mainly interpreted concentration of ne-grained ( 20 m), low-coercivity ferromagnetic fl as inner shelf deposits (Yan et al., 2008), 20–25 cm spaced, unoriented minerals that re ect detrital magnetite in sediment deposited in the sampling was conducted. The sampling of the 173.47–200.35 m interval shallow marine environments (Wu et al., 2012; Hinnov et al., 2013). of the deeper sedimentary environment (Lai et al., 2008; Yan et al., ARM values within the Maokou Formation cyclically range from 0.044 −6 2 2008) was about every 15 cm. For this study, a total of 948 samples to 4.9 × 10 Am /kg (Fig. 2). The carbonates have lower values than were obtained from the Maokou Formation. Weathered and fractured nodular chert-bearing and siliciclastic beds (Fig. 1d). zones were avoided by shifting laterally to better exposures. Sepiolite- bearing (argillaceous) limestone is composed of lime mudstones and 4.2. Cyclostratigraphy bioclastic wackstones (Yan et al., 2005) and we sampled only the lime mudstones from these intervals. 4.2.1. Spectral analysis The anhysteretic remanent magnetization (ARM) measurements The MTM spectrum of the ARM series has main peaks exceeding the were conducted at the Paleomagnetism and Environmental Magnetism 99% confidence level at wavelengths centered at 15.36, 1.67, 1.35, 1.15, Laboratory in the China University of Geosciences (Beijing). The rock 0.98, 0.9, 0.83, 0.79, 0.75, 0.73, 0.69, 0.67, 0.64, 0.62, 0.6, and 0.55 m, and

Fig. 2. (a) Lithostratigraphy, biostratigraphy, sequence stratigraphy, cyclostratigraphy, and ARM series in the stratigraphic domain. The lithostratigraphy and bed numbers are modified from Yan et al. (2008). Conodont biozones are integrated from Sun et al. (2008) and Fang et al. (2012). The local sequence stratigraphic explanations are based on Xie et al. (2008) (SB, sequence boundary; TST, transgressive systems tract; HST, highstand systems tract). The blue dashed line defines the 7% weighted average curve. The interpreted 405 kyr eccentricity cycles (red curve) were extracted with Gaussian filters with passbands of 0.135 ± 0.038 cycles/m (−0.75–29.85 m), 0.06 ± 0.012 cycles/m (29.85–89.85 m), and 0.1485 ± 0.06 cycles/m (89.25–200.25 m). The “e” and “E” represent the 100 kyr and 405 kyr eccentricity cycles, respectively. Q. Fang et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859 851 numerous peaks that exceed the 95% and 90% confidence levels the stratigraphic domain with the aid of evolutionary spectral analysis. (Fig. 3a). Due to dramatic changes in sedimentation rate in the shallow Inspection of the FFT spectrogram reveals four horizons of ~29.85 m, platform environment, the prerequisite is to evaluate frequency shifts in ~89.85 m, ~129.85 m, and ~145.85 m where sedimentation rates 852 Q. Fang et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859 appear to change. The horizons at ~29.85 m and ~89.85 m show more conodont sequence. The first appearance datum (FAD) of J. postserrata dramatic changes than the other two. FFT spectrogram shows that the in the deeper sedimentary environment has been identified at low-frequency components shift toward lower frequencies in the 179.55 m (Sun et al., 2008; Fang et al., 2012). To provide useful con- 29.85–89.85 m interval, which implies an increase in sedimentation straints to astronomers constructing more precise astronomical solu- rate. Thick-bedded sepiolite-bearing limestone with abundant tions in the Paleozoic, we here anchor the 179.55 m datum to the bioclastic contributions in this interval (Fig. 2) supports this interpreta- numerical age of 265.1 Ma due to the absence of direct radioisotope tion. Accordingly we divided dataset into three subsets for further age constraints for the Maokou Formation. The Maokou Formation con- spectral analysis (arrows in Fig. 3b). sists of twenty-four 405 kyr long eccentricity cycles with a total dura- Three stratigraphic subsets (−0.75–29.85 m, 29.85–89.85 m, and tion of ~9.7 myr. Thus, we constructed a “floating” ATS ranging from 89.85–200.25 m) were separated for spectral analysis (Fig. 3c–e). To in- 273.9 to 264.2 Ma for the Maokou Formation. This floating time scale terpret the wavelengths of significant spectral peaks in terms of possible may shift if we obtained a more precise geochronology or chose a differ- astronomical periods, we calculated their ratios and compared them to ent anchor point. astronomical period ratios for the Middle Permian as follows. The predicted Middle Permian astronomical periods are 405 kyr for long eccentricity (E), 124 kyr (e1) and 95 kyr (e2) for short eccentricity 4.2.4. Amplitude modulation (AM) envelope analysis (with an average of 100 kyr), 43.7 kyr (O1) and 34.8 kyr (O2) for obliq- Amplitude modulation (AM) envelope analysis is an effective way to uity, and 20.9 kyr (P1) and 17.5 kyr (P2) for precession (Berger and test whether observed cycles were astronomically controlled Loutre, 1994). In Subset 1 (−0.75–29.85 m), the wavelengths of 5.92, (e.g., Hinnov, 2000). The AM envelopes of the interpreted 405, 95, and 1.85, 1.34, 0.67, and 0.53 m have a ratio of 405:126:92:45.9:36.1 33 kyr bands of the 405 kyr-calibrated ARM time series reveal long- (Fig. 3c). These are interpreted as the E1, e1, e2, O1, and O2 astronomical period cycles. The AM envelope of the 405 kyr cycles has spectral cycles, respectively. In Subset 2 (29.85–89.85 m), the wavelengths peaks at mainly 4760, 1950, 1060, and 880 kyr (Fig. 6a, b), and that of of 15.36, 3.66, 1.67, 1.31, 0.78, and 0.65 m represent a ratio of the AM of 96 kyr signal shows spectral peaks at mainly 1950, 1300, 405:96:44.2:34.7:20.6:17.2 that is proportionally similar to the Middle and 840 kyr (Fig. 6c, d). The amplitude spectrum shows that the AM en- Permian astronomical period ratio (Fig. 3d). Thus, these wavelengths velope series of the 33 kyr filter output has spectral peaks at mainly are ascribed to the E, e2, O1, O2, P1, and P2. Likewise, in Subset 3 3380, 1370, and 1010 kyr (Fig. 6e, f). (89.85–200.25 m), the wavelengths of 6.99–8.54, 1.79–1.99, 0.61–0.71, and 0.38–0.41 m could be explained as E, e, O (combined O1 and O2) and P (combined P1 and P2) (Fig. 3e). Other wavelengths 5. Discussion also exceed the 99% confidence level (Fig. 3), which may be explained by shorter-term changes in sedimentation rate within subsets. 5.1. Durations of conodont zones Subset 2 (29.85–89.85 m) shows longer significant wavelengths (higher sedimentation rates) than the others, and therefore the ARM The constructed ATS may be applied to investigate astronomical stratigraphic series was divided into three parts, −0.75–29.85 m, forcing, and to develop timing estimates for geological events and strat- 29.85–89.85 m and 89.25–200.25 m, for filtering and astronomical cali- igraphic units recorded in the Maokou Formation. Considering the pos- bration. The results indicate a total of twenty-four 405 kyr eccentricity sibility that a 405 kyr long eccentricity cycle was either overlooked or cycles (Fig. 2). counted twice, a rough error estimate of ±0.4 myr was assumed for this ATS (e.g., De Vleeschouwer et al., 2012). The Roadian Stage 4.2.2. Astronomical calibration (J. nankingensis zone) is in the interval from 47.7 m to 129.75 m, and it The 405 kyr orbital eccentricity cycle has been consistent through- consists of nine 405 kyr eccentricity cycles (Fig. 2) with an estimated out geologic time by virtue of the stable orbits of Jupiter and Venus duration of 3.7 ± 0.4 myr (271.7–268 Ma). The Wordian Stage (Laskar et al., 2004). Therefore, it is possible to utilize this cycle for (J. aserrata zone) ranging from 129.75 m to 179.55 m includes six astrochronology prior to the Mesozoic Era (e.g., De Vleeschouwer 405 kyr eccentricity cycles (Fig. 2). The duration of Wordian Stage is et al., 2013; Wu et al., 2013a). The three subsets of log-transformed 2.9 ± 0.4 myr (268–265.1 Ma). The portion of the Capitanian Stage ARM series were astronomically calibrated via the inferred 405 kyr that is contained by the studied section (179.55–200.4 m) consists of orbital eccentricity cycles. The MTM power spectrum of the 405 kyr- two and a half 405 kyr eccentricity cycles (Fig. 2). Its estimated duration calibrated ARM series has spectral peaks at mainly ~405, ~44, and is 1 ± 0.4 myr (265.1–264.1 Ma). ~33 kyr above the 99% confidence level, at ~95 and ~17 kyr above the The 3.7 ± 0.4 myr duration of the Roadian Stage is in good agree- 95% confidence level, and at ~21 kyr above the 90% confidence level ment with that given in GTS2012 (3.5 ± 1 myr; Table 1). The 2.6 ± (Fig. 4). The influence of obliquity should be most pronounced in the 0.4 myr duration of the Wordian Stage falls outside the error margin high latitudes (Herbert, 1986); however, the occurrence of significant in GTS2012 (3.7 ± 0.9 myr; Table 1). It should be noted that, without ~33 and ~44 kyr obliquity cycles in the Maokou Formation at a low lat- any radiometric ages from mid-Artinskian to Wordian (~25 myr), the itude indicates that obliquity forcing exerted a significant influence on confidence intervals of the numerical ages of the basal Kungurian, paleoclimatic change near the Equator, probably related to contraction Roadian, and Wordian stages are ±0.5–0.6 myr in GTS2012. The nu- and expansion of the ice sheet in eastern Gondwana. merical ages assigned to the bottom of the Roadian and Wordian stages In the low frequencies, the 405 kyr-calibrated ARM time series were obtained by applying a smooth spline fitonthetwo-wayplotbe- shows spectral peaks at 3000, 2190, 1740, 1050 and 840 kyr (inset tween the composite standard scaling of the stages and radiometric graph in Fig. 5a). MTM amplitude spectral analysis can be used to refine ages. This modeling tends to produce overly optimistic confidence inter- the frequency identification of spectral peaks (e.g., Kodama and Hinnov, vals (De Vleeschouwer and Parnell, 2014). Thus, we do not reject our re- 2014). The 2π MTM amplitude spectrum of the calibrated ARM time se- sults simply because they fall outside the error margins of GTS2012. ries shows strong peaks at 2100 kyr and 1050 kyr (Fig. 5a). These peaks Because of global regression in the late Capitanian (Haq and are confirmed by wavelet analysis (Fig. 5b). Schutter, 2008), the sedimentary records between the Guadalupian and Lopingian horizons were mostly interrupted by a terrigenous bed 4.2.3. Construction of the floating astronomical time scale (ATS) in the South China Block. In the studied section, the marine sediment In GTS2012, the basal Capitanian Stage (265.1 ± 0.4 Ma) was de- of the Capitanian age is truncated by the terrigenous Wangpo Bed. fined by the FAD of J. postserrata (Gradstein et al., 2012). The upper Thus, the duration of the portion of the Capitanian at Shangsi is only Maokou Formation is extremely fossiliferous and yields a continuous 1 ± 0.4 myr, far less than the 5.3 ± 0.8 myr in GTS2012 (Table 1). Q. Fang et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859 853

(a) 99% 15.36 0.79 2.56 0.75 95% 6.67 0.73 1.67 0.83 90% 4.65 0.69 8.54 0.9 E 1.35 0.55 50% 7.69 0 0.67 10 1.15 0.48 (e) 0.64 6.99 0.98 0.44 1.99 e 0.62 O -1 1.91 0.71 10 0.6 0 P 10 1.79 0.64 Power 0.41 0.79 0.61 -1 0.38 10-2 10 0.5

10-2 10-3 200 190 E 15.36 E 180 e P O 3.66 e2 170 e 1.67 O1 0.78 P1 E 160 1.99 1.31 O2 0.69 100 1.15 150 O 0.65 P2 Power 10-1 (d) 140 O Subset 3 130 e 10-2 120 E e O 110 e 100 E O 90 5.92 E Depth (m) 1.85 e1 80 0.82 100 70 E 1.34 e2 0.67 O1 -1 60 10 0.53 O2 (c) 50 P 10-2 e O 40 30 E 20 e O (b) 00.51 1.5 2 2.5 3 10 Frequency (cycles/m) Subset 10 Subset 2 0.51 1.5 2 2.5 3 0 Frequency (cycles/m)

Fig. 3. (a) 2π MTM power spectrum of the ARM series of the Maokou Formation, with signiﬁcant peaks labeled in meters. The red, green, purple and blue solid lines represent the conventional AR (1) model and the 90%, 95%, and 99% conﬁdence levels. (b) FFT spectrogram, with a 20 m sliding window and the stratigraphic subsets. The white dashed lines labeled with E, e, O, and P represent the long eccentricity, short eccentricity, obliquity, and precession cycles, respectively. The black arrows illustrate the boundaries of stratigraphic subsets. (c–e) 2π MTM power spectra of the ARM stratigraphic series subsets of −0.75–29.85 m, 29.85–89.85 m, and 89.85–200.25 m, respectively.

5.2. Chaotic behavior of the planets during the Late Paleozoic deglaciation The low-frequency spectrum of the 405 kyr-calibrated ARM time series shows peaks around 2000 kyr (Fig. 5a) that are shorter than the The motions of the planetary orbits are measured by orbital longi- ~2.4 myr of the Cenozoic Era. The amplitude spectrum of the AM tude of perihelion (gi) and orbital inclination (si)(irangesfrom1to9, envelope curve of the 405 kyr and 100 kyr eccentricity filter output in order of distance from the Sun to Mercury, Venus, Earth, Mars, Jupiter, (Fig. 6a, c) also show significant peaks at 1950 kyr (Fig. 6b, d). Moreover, Saturn, Uranus, Neptune, and Pluto). Interactions among the motions of the low-pass filtered ARM series shows that short eccentricity cycles are the planetary orbits lead to the vibration of Earth's orbital parameters. bundled by the long eccentricity cycles throughout the Maokou Forma- Importantly, the orbital motions of Mars and Earth have a secular tion (Fig. 7b) and that the 405 kyr eccentricity is modulated by ~2 myr resonance presenting as (s4–s3)–2(g4–g3) = 0 that can range into cycles (Fig. 7c). We interpret the ~2 myr period as a long-term eccen- (s4–s3)–(g4–g3) = 0 due to chaotic behavior of the planets (Laskar, tricity cycle, which corresponds to the g4–g3 eccentricity term. 1990). Therefore, the g4–g3 and s4–s3 terms are expected to have Relative stability of g4–g3 is recorded in Cenozoic continental and changed throughout geologic time. marine strata (e.g., Lourens et al., 2005; van Dam et al., 2006; Abels

The g4–g3 term has been estimated by astronomical models for the et al., 2010). However, in older Mesozoic strata, g4–g3 shows unstable Cenozoic Era, but its exact period in the Paleozoic is unknown, because behavior: 2.5 myr from a Late Cretaceous and Early Paleocene DSDP of the chaotic diffusion in the inner Solar System (Laskar et al., 2004). core from the South Atlantic (Herbert, 1999); 2.6 and 2 myr from the 854 Q. Fang et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859

Ee O1 O2 P1 P2 of the obliquity signal is in phase with the low-pass and band-pass ﬁ 405 ltered ARM series at the 1 myr frequency band (Fig. 8). Thus, we inter- 1 95.2 10 44.6 pret the ~1 myr cycles as an amplitude modulation of obliquity, which is 33.2 72.4 48.5 17.3 associated with the s4–s3 term. 100 57.5 34.6 20.9 In contrast to the Cenozoic Era (e.g., Beaufort, 1994; Wade and r 29.1 10-1 Pälike, 2004; Pälike et al., 2006; Holbourn et al., 2007; Lirer et al., 2009), the periodicity of s –s appears to have been shorter in Mesozoic Powe -2 4 3 10 and Paleozoic strata, e.g., ~1 myr from the Late Cretaceous Jordanian 10-3 Levant Platform (Wendler et al., 2014) and ~1.12 myr from the Late Devonian central Appalachian Basin (McClung et al., 2013). The geologic

evidence from the Maokou Formation indicates shortened g4–g3 and s4–s3 periodicities, but that the critical argument θ, from θ =(s4–s3)– 0 0.01 0.02 0.03 0.040.05 0.06 0.07 2(g4–g3), was still around 0 at the end of the LPIA. Frequency (cycles/kyr) 5.3. Origin of the third-order eustatic sequences Fig. 4. 2π MTM power spectrum of the 405 kyr-calibrated ARM time series with significant peaks labeled in kiloyears. The colored lines are as in Fig. 3. The gray shaded band is mag- nified and shown in the inset graph in Fig. 5a. Changes in the distribution of incoming insolation may control sea level, and hence control sedimentation processes in the marine system. Conventionally, marine stratigraphic sequences are ascribed into six or- ders (Haq et al., 1987; Vail et al., 1991). The third-order sequences are Late Cretaceous terrestrial sequence of the Songliao Basin, China (Wu often explained by both tectonic and climatic effects (e.g., Vail et al., et al., 2013b, 2014); 1.5 myr from mid-Cretaceous deep water sedi- 1991). Middle Permian is divided into three stages based on the FADs of ments, Italy (Grippo et al., 2004); 2 myr from Late Jurassic hemipelagic specific species from lineages of conodonts (Henderson et al., 2012). sediments, England (Huang et al., 2010) and marine marls of the Terres The numerical ages of the sequence boundaries (R1, W1, and C1) are Noires Formation, France (Boulila et al., 2010); 1.6 myr from an early equivalent to those of the basal Roadian, Wordian, and Capitanian stages Jurassic drill core in the Paris Basin, France (Boulila et al., 2014); in the GTS2012. In the studied section, the FAD of J. postserrata (basal 1.75 myr from the GSSP candidate section for the Rhaetian Stage, Capitanian Stage) is more reliable than that of J. nankingensis and Austria (Hüsing et al., 2011) and Late Triassic lacustrine strata of the J. aserrata, because the linage of J. aserrata–J. postserrata was recognized Newark Basin, USA (Olsen and Kent, 1999); and 1.8 myr from Middle in a deeper sedimentary environment (Sun et al., 2008; Fang et al., Triassic rhythmic bedded cherts, Japan (Ikeda et al., 2010; Ikeda and 2012). The global sequence boundary C1 assigned to the chronology of Tada, 2013, 2014). Even as far back as the Paleozoic Era, long-period ec- GTS2012 differs only by ~1 kyr from the maximum point between the centricity of 2.2 to 2.4 myr was detected in the Viséan Windsor Group, cycle LO8 and LO9 (Fig. 8). Thus, we will correlate these two points, and Canada (Giles, 2009) and the Late Devonian Kowala section, Poland compare the durations of obliquity modulation cycles extracted from (De Vleeschouwer et al., 2013). the 405 kyr-calibrated ARM time series and global third-order sea-level The strong obliquity signal provides an opportunity to analyze its sequences from previous studies (Table 2). long-term modulations. The power spectrum shows that the AM enve- In GTS2012, the numerical ages of the global eustatic boundaries, K2, lope series of the 33-kyr filter output (Fig. 6e) has a peak at 1010 K3, K4, R1, R2, W1, W2, W3, C1, and C2, are 275.5, 273.7, 273, 272.3, (Fig. 6f), which is close to ~1000 kyr in the spectrum of the astronomi- 269.4, 268.8, 267.5, 266.4, 265.1 and 264 Ma, respectively (GTS2012 cally calibrated ARM series (Fig. 5a). In addition, the AM envelope curve modified from Haq and Schutter, 2008; Fig. 8). According to this

(a) 2190 405 3000 1740 2100 400 300 1050 840 (b) 125 2 200 Power 100 250 1050 0 1.5 0 0.001 500 Frequency (cycles/kyr)

Amplitude 1000

1 Period (kyr)

2000 0.5 273272 271 270 269 268 267 266 265 0 Time (Ma) 00.001 0.002 0.003 0.004 0.005 Frequency (cycles/kyr)

Fig. 5. Low-frequency component of 405 kyr-calibrated ARM series. (a) 2π MTM amplitude spectrum of the astronomically calibrated ARM series. Inset graph is the low-frequency part of the 2π MTM power spectrum of the astronomically calibrated ARM series in the shaded interval of Fig. 4. The amplitude spectrum provides a more reﬁned assessment of the low frequencies than the power spectrum. All peaks are labeled in kiloyears. (b) Wavelet scalogram of low-frequency component of 405 kyr-calibrated ARM series. Blue represents low spectral power, and red represents high spectral power. White numbers indicate periodicity in kyr. Q. Fang et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859 855 (a) (b) 0.4 1950 4760 1060 0.2 1000 880 8000 6 660 0 6000 4 Power 4000 Amplitude -0.2 Amplitude 2 2000 -0.4 0 0 273272 271 270 269 268 267 266 265 00.001 0.002 Time (Ma) Frequency (cycles/kyr)

Power 840

Amplitude 4000 -0.1 10

-0.2 0 0 273272 271 270 269 268 267 266 265 0.001 0.002 Time (Ma) Frequency (cycles/kyr)

(e) (f) 3380 0.06 2350 40 0.04 1370 735 20000 1010 0.02 660 30 0 20 -0.02 Power 10000 Amplitude Amplitude Amplitude -0.04 10 -0.06 0 0 273272 271 270 269 268 267 266 265 00.001 0.002 Time (Ma) Frequency (cycles/kyr)

Fig. 6. Amplitude modulation (AM) analysis of the 405 kyr long eccentricity, 100 kyr short eccentricity, and obliquity signals and 2π MTM power and amplitudes spectra computed with AnalySeries (Paillard et al., 1996). The red solid lines deﬁne the AM envelopes. The numbers in the MTM spectra are labeled in kiloyears. (a), (c), and (e) show the AM envelopes of long eccentricity, short eccentricity, and obliquity. Gaussian ﬁlters of the 405 kyr-calibrated ARM time series extracted with passbands of 0.00246 ± 0.0015, 0.0105 ± 0.001, and 0.0295 ± 0.0014 cycles/kyr, respectively. (b), (d), (f) are power (black solid lines) and amplitudes (red dashed lines) spectra of the AM envelopes shown in (a), (c) and (e).

chronology, the durations of these third-order eustatic sequences are 0.95 myr (LO1), 0.97 myr (LO2), 1.47 myr (LO3), 0.96 myr (LO4), 1.8 myr (K2–K3), 0.7 myr (K3–K4), 0.7 myr (K4–R1), 2.9 myr (R1– 0.95 myr (LO5), 0.96 myr (LO6), 1.02 myr (LO7), 1.02 myr (LO8), and R2), 0.6 myr (R2–W1), 1.3 myr (W1–W2), 1.1 myr (W2–W3), 1.3 myr 0.92 myr (LO9). We suggest that these two sets of durations are tenta- (W3–C1), and 1.1 myr (C1–C2). The estimated durations of the long- tively comparable, considering the large uncertainty in the GTS2012. term obliquity cycles extracted from the Maokou Formation are Thus, the third-order eustatic sequences could be in tune with the

s4–s3 obliquity modulation term at the end of the LPIA. The durations of LO1 and LO4 are shorter than K2–K3 and R1–R2 sequences, respectively, and LO3 is about twice the duration of the K4–R1 sequence Table 1 (Table 2). Alternatively, if we shifted the ﬂoating age model by ~1 myr Comparison of estimated durations of conodont zones at Maokou Formation with toward younger ages so that LO1 corresponds to the K3–K4 sequence, GTS2012 (Gradstein et al., 2012). modulation of the obliquity signal would correlate better with the eu- Stages Conodont zones Estimated duration (myr) static sequences in terms of duration. Based on this solution, however, GTS 2012 This paper the studied section would include two third-order sea-level sequences of Capitanian age (C1–C2 and C2–C3) with a greater than 2 myr dura- Capitanian 5.3 ± 0.8 Jinogondolella postserrata 1 ± 0.4 tion. The Capitanian Stage contains six conodont zones, with an average Wordian 3.7 ± 0.9 duration of ~1 myr per conodont zone. In the studied section only one Jinogondolella aserrata 3.7 ± 0.9 2.9 ± 0.4 conodont zone in the Capitanian Stage was recognized (Sun et al., Roadian 3.5 ± 1 2008; Fang et al., 2012), which argues against a ~1 myr shift from our Jinogondolella nankingensis 3.5 ± 1 3.7 ± 0.4 proposed anchor point. 856 Q. Fang et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859

E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 E11 E12 E13E14 E15 E16 E17 E18 E19 E20 E21E22 E23 E24 -5.5 (a) -6 -6.5 Log (ARM) 0.4 -7 0 (b) 0.2 -0.4 (c) 0 Lowpass filter LE1 LE2 -0.2 LE3 LE4

Bandpass filter 273272 271 270 269 268 267 266 265 Time (Ma)

Fig. 7. Low-pass and band-pass filtering of the 405 kyr-calibrated ARM time series illustrating long-period eccentricity variations. (a) 405 kyr-calibrated log-transformed ARM time series with low-pass filter output to extract ~2 myr eccentricity and longer periods with a cutoff frequency of 0.0008 cycles/kyr (red line). E1–E24 represent the interpreted 405 kyr eccentricity cycles. (b) Low-pass filter output of 405 kyr eccentricity and longer periods with a cutoff frequency of 0.0032 cycles/kyr (red dashed line) and 100 kyr eccentricity and longer period with cutoff frequency of 0.015 cycles/kyr (black line). (c) Interpreted long-term eccentricity cycles labeled as LE1–LE4 were extracted with a bandpass filter with a passband of 0.00049 ± 0.00017 cycles/kyr.

Obliquity has been interpreted as the driver of ice sheets dynamics in only by astronomical forcing alone at the apex of the glaciation. Very icehouse worlds (Zachos et al., 2001a). However, the waning and large ice volumes cannot ablate during the warm summers due to waxing of the massive Gondwanan ice sheet was likely driven not their very cold surfaces. Instead the small ice sheet on eastern

Time (Ma) (g) ~1 myr 273272 271 270 269 268 267 266 265 1 0.8 (a) -7 FAD of J. postserrata 0.6 0.4 -6.5 Coherence 0.2 0 -6 (b) 100 Log (ARM) )

-0.3 ° 50 -5.5 -0.2 0 -0.1 -50 (c) 0 Phase( -100 -7 0.1 -4×10 0.2 -7 -2×10 0.3 Lowpass filter 0 0.001 0.002 0.003 0.004 0 Frequency (cycles/kyr)

2×10-7

Bandpass filter LO1 LO2 4×10-7 LO5 (d) LO3 LO4 LO6 LO8 LO9 (h) ~1 myr LO7 1 0 0.8 0.6 (e) 0.04 0.4

0.08 Coherence 0.2 Hilbert output 0 SB1 SB2 SB3 (f) 100 )

° 50 0 -50 Phase( Local third-order sea-level sequences K2 K3 K4 R1 R2W1 W2 W3C1 C2 -100

0 0.001 0.002 0.003 0.004 276 275 274 273272 271 270 269 268 267 266 265 264 Frequency (cycles/kyr) Time (Ma) Global third-order sea-level seqeunces

Fig. 8. Low-pass and band-pass filtering of the 405 kyr-calibrated ARM time series illustrating the correlation of long-period obliquity cycles and global third-order sequences. (a) The 405 kyr- calibrated log-transformed time ARM series. (b) Low-pass filter output using a cutoff frequency of 0.0016 cycles/kyr to extract ~1 myr and longer periods. (c) Band-pass filter output using a passband of 0.0009 ± 0.0003 cycles/kyr to extract the LO1–LO9 cycles. (d) Hilbert transformed output of obliquity modulation is from Fig. 6e. (e) SB1–SB3 are the local third-order sequence boundaries (Xie et al., 2008) that are pegged at 271.7 Ma, 268 Ma, and 265.3 Ma, respectively. (f) Global third-order sequence boundaries using the time scale in GTS2012. K, R, W, andCrep- resent the Kungurian, Roadian, Wordian, and Capitanian stages, respectively. (g) Coherency and cross-phase analysis of (c) versus (d). (h) Coherency and cross-phase analysis of (b) versus (d). Q. Fang et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859 857

Table 2 than the 1.2 myr predicted for and detected in the Cenozoic Era. From Comparison of the durations of the third order sea-level sequences (GTS2012 modified this we interpret that 2:1 secular resonance of g4–g3 and s4–s3 is pre- from Haq and Schutter, 2008) with long-term obliquity signal from the Maokou served throughout the section, and that the orbits of Earth and Mars Formation. maintained the resonance (s4–s3)–2(g4–g3) = 0 at the end of the LPIA. 3rd order sequence Duration (myr) Astronomical cycle Duration (myr) A correspondence between the LO1 to LO9 cycles extracted from the K2–K3 1.8 LO1 0.95 ARM series and the global third-order eustatic sequences provides evi- K3–K4 0.7 LO2 0.97 dence that third-order sea-level sequences were astronomically paced K4–R1 0.7 LO3 1.47 by s4–s3 obliquity modulations and were glacioeustatically controlled R1–R2 2.9 LO4 0.96 R2–W1 0.6 LO5 0.95 at the end of the LPIA. W1–W2 1.3 LO6 0.96 W2–W3 1.1 LO7 1.02 W3–C1 1.3 LO8 1.02 Acknowledgments C1–C2 1.1 LO9 0.92 The authors are grateful for the help from Jingya Wang, Haiyan Li and Jing Lu in the lab. Qiang Fang thanks Chris Fielding and Brooks B. Ellwood for their help. We express our sincere appreciation to the jour- Gondwana may have been more sensitive to astronomical forcing at the nal editor (Prof. Thierry Corrège) and two reviewers (Dr. David De end-LPIA deglaciation (Horton and Poulsen, 2009; Horton et al., 2010). Vleeschouwer and Dr. Slah Boulila) for their careful reviews and con- During the Cenozoic, the long-period nodes of the obliquity were asso- structive suggestions. This study was supported by the National Science ciated with glaciation events (Zachos et al., 2001b; Pälike et al., 2006; Foundation of China (41422202), the Fundamental Research Funds for Boulila et al., 2011). Ice expansion during obliquity nodes was the result the Central Universities (2-9-2015-297) and National Key Basic of cooler summers and lower ablation rates. The major cooling trends Research Development Program of China (2012CB822002). thus induced a lowering of sea level and gave rise to sequence boundaries (Haq et al., 1987) and possibly, peak erosion rates and increased terrigenous flux to the marine system reflected by the maxima of the Appendix A. Supplementary data ARM series. In summary, the global third-order sea-level sequences are likely associated with glacial episodes, and therefore were Supplementary data associated with this article can be found in glacioeustatically controlled at the end of the LPIA. the online version, at http://dx.doi.org/10.1016/j.palaeo.2015.10.014. Interestingly, three third-order eustatic boundaries (SB1, SB2, and These data include the Google maps of the most important areas SB3) recognized by Xie et al. (2008) in the Maokou Formation appear describe in this article. to be correlated with global counterparts (K4, W1, and C1; Fig. 8). The duration of SB1–SB2 (from 47.4 m to 129.75 m) is ~4 myr based on our floating ATS. However, the duration of the third-order eustatic References – sequence is 0.5 3 myr according to Haq et al. (1987) and Vail et al. Abels, H.A., Aziz, H.A., Krijgsman, W., Smeets, S.J.B., Hilgen, F.J., 2010. Long-period eccen- (1991), and the global sea-level curve indicates high frequency eustatic tricity control on sedimentary sequences in the continental Madrid Basin (middle fluctuations from the Kungurian to the Capitanian (Haq and Schutter, Miocene, Spain). Earth Planet. Sci. Lett. 289, 220–231. fi Angiolini, L., Crippa, G., Muttoni, G., Pignatti, J., 2013. Guadalupian (Middle Permian) 2008; Rygel et al., 2008). Thus, it raises questions about the de nition paleobiogeography of the Neotethys Ocean. Gondwana Res. 24, 173–184. of depositional sequences. As the Late Paleozoic ice sheets decayed, Beaufort, L., 1994. Climatic importance of the modulation of the 100 kyr cycle inferred the amplitude of sea-level fluctuations would have decreased. A damp- from 16 my long Miocene records. Paleoceanography 9, 821–834. fi Berger, A., Loutre, M.F., 1994. Astronomical forcing through geological time. In: De Boer, ened glacioeustasy brings about more dif culty in recognizing the P.L., Smith, D.G. (Eds.), Orbital Forcing and Cyclic Sequences. Blackwell Scientific hierarchy of depositional sequences. Our high-resolution astronomical Publications, Oxford, pp. 15–24. interpretation for sequence stratigraphy of the Maokou Formation Boulila, S., Galbrun, B., Hinnov, L.A., Collin, P.Y., Ogg, J.G., Fortwengler, D., Marchand, D., affords an alternative approach to estimate the durations of the sequences, 2010. Milankovitch and sub-Milankovitch forcing of the Oxfordian (Late Jurassic) Terres Noires Formation (SE France) and global implications. Basin Res. 22, 717–732. and for global correlation through a combination of cyclostratigraphy Boulila, S., Galbrun, B., Miller, K.G., Pekar, S.F., Browning, J.V., Laskar, J., Wright, J.D., 2011. and sequence stratigraphy. On the origin of Cenozoic and Mesozoic “third-order” eustatic sequences. Earth Sci. Rev. 109, 94–112. Boulila, S., Galbrun, B., Huret, E., Hinnov, L.A., Rouget, I., Gardin, S., Bartolini, A., 2014. As- tronomical calibration of the Toarcian Stage: implications for sequence stratigraphy 6. Conclusion and duration of the early Toarcian OAE. Earth Planet. Sci. Lett. 386, 98–111. Chen, H.H., Sun, S., Li, J.L., Heller, F., Dobson, J., 1994. Permo-Triassic magnetostratigraphy in Wulong area, Sichuan, China. Sci. China Ser. B: Chem. 37, 203–212. Cyclostratigraphic analysis of a high-resolution ARM series was con- Chen, B., Joachimski, M.M., Shen, S.Z., Lambert, L.L., Lai, X.L., Wang, X.D., Chen, J., Yuan, ducted on the Maokou Formation at the Shangsi section, South China. D.X., 2013. Permian ice volume and palaeoclimate history: oxygen isotope proxies According to conodont biostratigraphy, the Maokou Formation ranges revisited. Gondwana Res. 24, 77–89. Cleveland, W.S., 1979. Robust locally weighted regression and smoothing scatterplots. from late Kungurian to early Capitanian age, coeval with the end of J. Am. Stat. Assoc. 74, 829–836. http://dx.doi.org/10.2307/2286407. the Late Paleozoic Ice Age (LPIA). Time series analysis reveals the pres- Davydov, V.I., Crowley, J.L., Schmitz, M.D., Poletaev, V.I., 2010. High-precision U–Pb zircon ence of astronomical signals with 405 kyr long eccentricity, ~95 kyr age calibration of the global Carboniferous time scale and Milankovitch band cyclicity in the Donets Basin, eastern Ukraine. Geochem. Geophys. Geosyst. 11, Q0AA04. short eccentricity, ~44 and ~33 kyr obliquity, and ~20 kyr precession http://dx.doi.org/10.1029/2009GC002736. cycles. The 405 kyr orbital eccentricity cycle is clearly expressed in the De Vleeschouwer, D., Parnell, A.C., 2014. Reducing time-scale uncertainty for the Devonian ARM series, and is used as an “astronomical metronome” to calibrate by integrating astrochronology and Bayesian statistics. Geology 42, 491–494. two conodont zones and durations of 3.7 ± 0.4 myr and 2.9 ± De Vleeschouwer, D., Whalen, M.T., Day, J.E.J., Claeys, P., 2012. Cyclostratigraphic calibration of the Frasnian (Late Devonian) time scale (western Alberta, Canada). Geol. Soc. 0.4 myr for the Roadian and Wordian stages, respectively. Considering Am. Bull. 124, 928–942. the large uncertainty in GTS2012, these estimated durations are charac- De Vleeschouwer, D., Rakocinski, M., Racki, G., Bond, D.P.G., Sobien, K., Claeys, P., 2013. terized by unprecedented precision of ±0.4 myr. The astronomical rhythm of Late-Devonian climate change (Kowala section, Holy Cross Mountains, Poland). Earth Planet. Sci. Lett. 365, 25–37. The ~2 myr cycles in the Maokou Formation ARM series correspond- De Vleeschouwer, D., Crucifix, M., Bounceur, N., Claeys, P., 2014. The impact of astronom- – ing to the combination of planetary secular frequencies g4–g3 are slight- ical forcing on the Late Devonian greenhouse climate. Glob. Planet. Chang. 120, 65 80. ly shorter than the 2.4 myr predicted for and detected in the Cenozoic Ellwood, B.B., Lambert, L.L., Tomkin, J.H., Bell, G.L., Nestell, M.K., Nestell, G.P., Wardlaw, – B.R., 2013. Magnetostratigraphy susceptibility for the Guadalupian series GSSPs Era, indicating instability in g4 g3 due to chaotic motion of the planets. (Middle Permian) in Guadalupe Mountains National Park and adjacent areas in The ~1 myr cycles corresponding to s4–s3 are likewise slightly shorter West Texas. Geol. Soc. Lond., Spec. Publ. 373, 375–394. 858 Q. Fang et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859

Fang, Q., Jing, X.C., Deng, S.H., Wang, X.L., 2012. Roadian–Wuchiapingian conodont Lai, X.L., Wang, W., Wignall, P.B., Bond, D.G., Jiang, H.S., Ali, J.R., John, E.H., Sun, Y.D., 2008. biostratigraphy at the Shangsi section, northern Sichuan. J. Stratigr. 36, 692–699 (in Palaeoenvironmental change during the end-Guadalupian (Permian) mass extinction Chinese with English abstract). in Sichuan, China. Palaeogeogr. Palaeoclimatol. Palaeoecol. 269, 78–93. Feng, Z.Z., Yang, Y.P., Jin, Z.K., He, Y.B., Wu, S.H., Xin, W.J., Bao, Z.D., Tian, J., 1996. Lithofacie Laskar, J., 1990. The chaotic motion of the solar system: a numerical estimate of the size of paleogeography of the Permian of South China. Acta Sedimentol. Sin. 14, 1–11 (in the chaotic zones. Icarus 88, 266–291. Chinese with English abstract). Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A.C.M., Levrard, B., 2004. A long- Fielding, C.R., Frank, T.D., Birgenheier, L.P., Rygel, M.C., Jones, A.T., Roberts, J., 2008a. term numerical solution for the insolation quantities of the Earth. Astron. Astrophys. Stratigraphic imprint of the Late Palaeozoic Ice Age in eastern Australia: a record of 428, 261–285. alternating glacial and nonglacial climate regime. J. Geol. Soc. 165, 129–140. Laskar, J., Fienga, A., Gastineau, M., Manche, H., 2011. La2010: a new orbital solution for Fielding, C.R., Frank, T.D., Isbell, J.L., 2008b. ThelatePaleozoiciceage—a review of current the long term motion of the Earth. Astron. Astrophys. 532, A89. understanding and synthesis of global climate patterns. Geol. Soc. Am. Spec. Pap. 441, Latta, D.K., Anastasio, D.J., Hinnov, L.A., Elrick, M., Kodama, K.P., 2006. Magnetic record of 343–354. Milankovitch rhythms in lithologically noncyclic marine carbonates. Geology 34, Geological Bureau of Sichuan Province (GBSP), 1966. Geological Survey Report of 29–32. Guangyuan Sheet (1:200,000) (in Chinese). Li, H.J., 2009. Sequence Stratigraphy Analysis and High Quality Source Rock Identification Ghil, M., Allen, M.R., Dettinger, M.D., Ide, K., Kondrashov, D., Mann, M.E., Robertson, A.W., in Typical Permian Section, Yangtze Area. China University of Geoscience (Wuhan), Saunders, A., Tian, Y., Varadi, F., Yiou, P., 2002. Advanced spectral methods for climatic Wuhan, pp. 36–42 (in Chinese with English abstract). time series. Rev. Geophys. 40 (1), 3-1–3-41. Lirer, F., Harzhauser, M., Pelosi, N., Piller, W.E., Schmid, H.P., Sprovieri, M., 2009. Astro- Giles, P.S., 2009. Orbital forcing and Mississippian sea level change: time series analysis of nomically forced teleconnection between Paratethyan and Mediterranean sediments marine flooding events in the Viséan Windsor Group of eastern Canada and implica- during the Middle and Late Miocene. Palaeogeogr. Palaeoclimatol. Palaeoecol. 275, tions for Gondwana glaciation. Bull. Can. Petrol. Geol. 57, 449–471. 1–13. Gradstein, F.M., Ogg, G., Schmitz, M., 2012. The Geologic Time Scale 2012 2-Volume Set. Lourens, L.J., Hilgen, F.J., 1997. Long-periodic variations in the Earth's obliquity and their pp. 1–1127. relation to third-order eustatic cycles and late Neogene glaciations. Quat. Int. 40, Grippo, A., Fischer, A.G., Hinnov, L.A., Herbert, T.D., Premoli Silva, I., 2004. 43–52. Cyclostratigraphy and chronology of the Albian stage (Piobbico core, Italy). Special Lourens, L.J., Sluijs, A., Kroon, D., Zachos, J.C., Thomas, E., Rohl, U., Bowles, J., Raffi, I., 2005. Publication—Society for Sedimentary Geology 81, pp. 57–81. Astronomical pacing of late Palaeocene to early Eocene global warming events. Na- Haq, B.U., Schutter, S.R., 2008. A chronology of Paleozoic sea-level changes. Science 322, ture 435, 1083–1087. 64–68. McArthur, J.M., Howarth, R.J., Shields, G.A., 2012. Strontium isotope stratigraphy. In: Haq, B.U., Hardenbol, J., Vail, P.R., 1987. Chronology of fluctuating sea levels since the Gradstein, F.M., Ogg, J.G., Schmitz, M.D., Ogg, G.M. (Eds.), The Geological Time Scale Triassic. Science 235, 1156–1167. 2012. Elsevier, pp. 127–144. Henderson, C.M., Davydov, V.I., Wardlaw, B.R., 2012. The Permian period. In: Gradstein, McClung, W.S., Eriksson, K.A., Terry Jr., D.O., Cuffey, C.A., 2013. Sequence stratigraphic hi- F.M., Ogg, J.G., Schmitz, M.D., Ogg, G.M. (Eds.), The Geological Time Scale 2012, erarchy of the Upper Devonian Foreknobs Formation, central Appalachian Basin, USA: pp. 653–678. evidence for transitional greenhouse to icehouse conditions. Palaeogeogr. Herbert, T.D., 1986. Milankovitch climatic origin of mid-Cretaceous black shale rhythms in Palaeoclimatol. Palaeoecol. 387, 104–125. central Italy. Nature 321, 739–743. Olsen, P.E., Kent, D.V., 1999. Long-period Milankovitch cycles from the Late Triassic and Herbert, T.D., 1999. Toward a composite orbital chronology for the Late Cretaceous and Early Jurassic of eastern North America and their implications for the calibration of Early Palaeocene GPTS. Philos. Trans. R. Soc. London, Ser. A 357, 1891–1905. the Early Mesozoic time-scale and the long-term behaviour of the planets. Philos. Hinnov, L.A., 2000. New perspectives on orbitally forced stratigraphy. Annu. Rev. Earth Trans. R. Soc. A Math. Phys. Eng. Sci. 357, 1761–1786. Planet. Sci. 28, 419–475. Paillard, D., Labeyrie, L., Yiou, P., 1996. Macintosh program performs time-series analysis. Hinnov, L.A., 2013. Cyclostratigraphy and its revolutionizing applications in the Earth and EOS Trans. Am. Geophys. Union 77, 379. Planetary Sciences. Geol. Soc. Am. Bull. 125, 1703–1734. Pälike, H., Norris, R.D., Herrle, J.O., Wilson, P.A., Coxall, H.K., Lear, C.H., Shackleton, N.J., Hinnov, L.A., Hilgen, F., 2012. Chapter 4: cyclostratigraphy and astrochronology. In: Tripati, A.K., Wade, B.S., 2006. The heartbeat of the Oligocene climate system. Science Gradstein, F., Ogg, J., Ogg, G., Smith, D. (Eds.), A Geologic Time Scale 2012. Elsevier, 314, 1894–1898. pp. 63–83. Rygel, M.C., Fielding, C.R., Frank, T.D., Birgenheier, L.P., 2008. The magnitude of late Paleo- Hinnov, L.A., Anastasio, D., Kodama, K., Elrick, M., Latta, D.J., 2013. Global Milankovitch zoic glacioeustatic fluctuations: a synthesis. J. Sediment. Res. 78, 500–511. cycles recorded in rock magnetism of the shallow marine Lower Cretaceous Cupido Scotese, C.R., Langford, R.P., 1995. Pangea and the paleogeography of the Permian, the Formation, northeastern Mexico. In: Jovane, L., Herrero-Bervera, E., Hinnov, L.A., Permian of Northern Pangea. Springer, pp. 3–19. Housen, B. (Eds.), Magnetic Methods and the Timing of Geological Processes. Geolog- Stanley, S.M., Yang, X., 1994. A double mass extinction at the end of the Paleozoic era. Sci- ical Society of London Special Publication 373, pp. 325–340. ence 266, 1340–1344. Holbourn, A., Kuhnt, W., Schulz, M., Flores, J.-A., Andersen, N., 2007. Orbitally-paced cli- Sun, Y.D., Lai, X.L., Jiang, H.S., Luo, G.M., Sun, S., Yan, C.B., Wignall, P.B., 2008. Guadalupian mate evolution during the middle Miocene “Monterey” carbon-isotope excursion. (Middle Permian) conodont faunas at Shangsi Section, northeast Sichuan Province. Earth Planet. Sci. Lett. 261, 534–550. J. China Univ. Geosci. 19, 451–460. Horton, D.E., Poulsen, C.J., 2009. Paradox of late Paleozoic glacioeustasy. Geology 37, Thomson, D.J., 1982. Spectrum estimation and harmonic analysis. Proc. IEEE 70, 715–718. 1055–1096. Horton, D.E., Poulsen, C.J., Pollard, D., 2010. Influence of high-latitude vegetation feed- Torrence, C., Compo, G.P., 1998. A practical guide to wavelet analysis. Bull. Am. Meteorol. backs on late Palaeozoic glacial cycles. Nat. Geosci. 3, 572–577. Soc. 79, 61–78. Huang, C.J., Hesselbo, S.P., Hinnov, L., 2010. Astrochronology of the late Jurassic Vail, P.R., Audemard, F., Bowman, S.A., Eisner, P.N., Perez-Cruz, C., 1991. The stratigraphic Kimmeridge Clay (Dorset, England) and implications for Earth system processes. signatures of tectonics, eustasy and sedimentology—an overview. In: Einsele, G., Earth Planet. Sci. Lett. 289, 242–255. Ricken, W., Seilacher, A. (Eds.), Cycles and Events in Stratigraphy. Springer, Berlin, Hüsing, S.K., Deenen, M.H.L., Koopmans, J.G., Krijgsman, W., 2011. Magnetostratigraphic pp. 617–659. dating of the proposed Rhaetian GSSP at Steinbergkogel (Upper Triassic, Austria): im- van Dam, J.A., Abdul Aziz, H., Sierra, M.A.A., Hilgen, F.J., Ostende, L.W.v.d.H., Lourens, L.J., plications for the Late Triassic time scale. Earth Planet. Sci. Lett. 302, 203–216. Mein, P., van der Meulen, A.J., Pelaez-Campomanes, P., 2006. Long-period astronom- Huybers, P., Denton, G., 2008. Antarctic temperature at orbital timescales controlled by ical forcing of mammal turnover. Nature 443, 687–691. local summer duration. Nat. Geosci. 1, 787–792. Wade, B.S., Pälike, H., 2004. Oligocene climate dynamics. Paleoceanography 19, 16. Ikeda, M., Tada, R., 2013. Long period astronomical cycles from the Triassic to Jurassic Wang, L., Lu, Y., Zhao, S., Luo, J., 1994. Permian Lithofacies, Paleogeography and Mineral- bedded chert sequence (Inuyama, Japan); geologic evidences for the chaotic behavior ization in South China. Geological Publishing House, Beijing, p. 147 (in Chinese with of solar planets. Earth Planets Space 65, 351–360. English abstract). Ikeda, M., Tada, R., 2014. A 70 million year astronomical time scale for the deep-sea Wendler, J.E., Meyers, S.R., Wendler, I., Kuss, J., 2014. A million-year-scale astronomical bedded chert sequence (Inuyama, Japan): implications for Triassic–Jurassic geochro- control on Late Cretaceous sea-level. Newsl. Stratigr. 47, 1–19. nology. Earth Planet. Sci. Lett. 399, 30–43. Wu, H.C., Zhang, S.H., Feng, Q.L., Jiang, G.Q., Li, H.Y., Yang, T.S., 2012. Milankovitch and sub- Ikeda, M., Tada, R., Sakuma, H., 2010. Astronomical cycle origin of bedded chert: a Milankovitch cycles of the early Triassic Daye Formation, South China and their geo- middle Triassic bedded chert sequence, Inuyama, Japan. Earth Planet. Sci. Lett. 297, chronological and paleoclimatic implications. Gondwana Res. 22, 748–759. 369–378. Wu, H.C., Zhang, S.H., Hinnov, L.A., Jiang, G.Q., Feng, Q.L., Li, H.Y., Yang, T.S., 2013a. Time- Isbell, J.L., Miller, M.F., Wolfe, K.L., Lenaker, P.A., 2003. Timing of late Paleozoic glaciation calibrated Milankovitch cycles for the late Permian. Nat. Commun. 4, 2452. in Gondwana: was glaciation responsible for the development of Northern Wu, H.C., Zhang, S.H., Jiang, G.Q., Hinnov, L.A., Yang, T.S., Li, H.Y., Wan, X.Q., Wang, C.S., Hemisphere cyclothems? Geol. Soc. Am. Spec. Pap. 5–24. 2013b. Astrochronology of the Early Turonian–Early Campanian terrestrial succession Isbell,J.L.,Henry,L.C.,Gulbranson,E.L.,Limarino,C.O.,Fraiser,M.L.,Koch,Z.J., in the Songliao Basin, northeastern China and its implication for long-period behavior Ciccioli, P.L., Dineen, A.A., 2012. Glacial paradoxes during the late Paleozoic ice age: of the Solar System. Palaeogeogr. Palaeoclimatol. Palaeoecol. 385, 55–70. evaluating the equilibrium line altitude as a control on glaciation. Gondwana Res. Wu, H.C., Zhang, S.H., Hinnov, L.A., Jiang, G.Q., Yang, T.S., Li, H.Y., Wan, X.Q., Wang, C.S., 22, 1–19. 2014. Cyclostratigraphy and orbital tuning of the terrestrial upper Santonian–Lower Kodama, K.P., Hinnov, L.A., 2014. Rock magnetic cyclostratigraphy. Wiley-Blackwell Fast- Danian in Songliao Basin, northeastern China. Earth Planet. Sci. Lett. 407, 82–95. Track MonographNew Analytical Methods in Earth and Environmental Science Series Xie, X.N., Li, H.J., Xiong, X., Huang, J.H., Yan, J.X., Qin, J.Z., Teng, E., Li, W., 2008. Main p. 140. controlling factors of organic matter richness in a Permian setion of Guangyuan, Lai, X.L., Yang, F.Q., Hallam, A., Wignall, P.B., 1996. The Shangsi section, candidate of the northeast Sichuan. J. China Univ. Geosci. 19, 507–517. global stratotype section and point of the Permian–Triassic boundary. In: Yin, H.F. Yan, J.X., Munnecke, A., Steuber, T., Carlson, E.H., Xiao, Y., 2005. Marine sepiolite in middle (Ed.), The Palaeozoic–Mesozoic Boundary, Candidates of the Global Stratotype Permian carbonates of South China: implications for secular variation of Phanerozoic Section and Point of the Permian–Triassic Boundary, pp. 113–124. seawater chemistry. J. Sediment. Res. 75, 328–338. Q. Fang et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 440 (2015) 848–859 859

Yan, J.X., Ma, Z.X., Xie, X.N., Xue, W.Q., Li, B., Liu, D.Q., 2008. Subdivision of Permian fossil Zeng, J., Cao, C.Q., Davydov, V.I., Shen, S.Z., 2012. Carbon isotope chemostratigraphy and communities and habitat types in northeast Sichuan, South China. J. China Univ. implications of palaeoclimatic changes during the Cisuralian (Early Permian) in the Geosci. 19, 441–450. southern Urals, Russia. Gondwana Res. 21, 601–610. Yao, X., Zhou, Y., Hinnov, L.A., 2015. Astronomical forcing of Middle Permian chert in the Zhong, Y.T., He, B., Mundil, R., Xu, Y.G., 2014. CA-TIMS zircon U–Pb dating of felsic ignim- Lower Yangtze area, South China. Earth Planet. Sci. Lett. 422, 206–221. brite from the Binchuan section: implications for the termination age of Emeishan Zachos, J., Pagani, M., Sloan, L., Thomas, E., Billups, K., 2001a. Trends, rhythms, and aber- large igneous province. Lithos 204, 14–19. rations in global climate 65 Ma to present. Science 292, 686–693. Zachos, J.C., Shackleton, N.J., Revenaugh, J.S., Pälike, H., Flower, B.P., 2001b. Climate re- sponse to orbital forcing across the Oligocene–Miocene boundary. Science 292, 274–278.