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Late Paleozoic deglaciation is the first icehouse‐to‐greenhouse transition in a world with expansive tropical forests, but the detailed process of this climatic upheaval is still debated due to lack of high‐precision global correlation. Here, based on the cyclostratigraphic analysis of a deep‐marine succession of Naqing in South China, chronostratigraphic correlation was achieved between Paleo‐Tethyan deep‐marine carbonate cyclicity and U‐Pb zircon age‐calibrated cyclothems from the Pangaean paleotropics. Refining the global chronostratigraphy indicates ages of 294.1 ± 0.2 Ma and 290.1 ± 0.2 Ma for the base of the Sakmarian and Artinskian stages, respectively. We juxtapose the climatic proxies and indicators across blocks and latitudes to decipher the trends and rhythms in climate change during a period from the apex of the Late Paleozoic ice age (LPIA) to the initial deglaciation. On the multiple‐million‐year time scale, the polar and equatorial climates were linked through the atmospheric pCO2 control. A rise in pCO2 promoted Gondwanan deglaciation and tropical aridification. The disparity in the inferred polarity of tropical climate changes during glacials and interglacials has been confirmed on the million‐year time scale. The meridional flux of moisture was enhanced during the minima of the ∼1.2 Myr obliquity cycle, periodically resulting in Gondwanan glaciation, glacio‐eustatic sea‐level lowerings, and reduced moisture availability in the tropical Pangaean and Paleo‐Tethyan regions. Our study provides an improved temporal resolution and understanding of the apex of the LPIA. Plain Language Summary: Cyclostratigraphic analysis of the Naqing section in South China indicates ages of 294.1 ± 0.2 Ma and 290.1 ± 0.2 Ma for the base of the Sakmarian and Artinskian stages, respectively. The marine and terrestrial records across continents were synchronized using a high‐resolution global correlation. The result indicates that the climatic changes were mainly in pace with 1.2 Myr obliquity cycles superimposed on long‐term Gondwana deglaciation and tropical aridification associated with an increase of pCO2 levels. These results reinforce a solid linkage between climate changes at low and high latitudes, regardless of the ice‐sheet volume. Key Points: Chronostratigraphy of Asselian and Sakmarian stages was refined by cyclostratigraphic analysis on a deep‐marine succession in South ChinaThe rise in atmospheric pCO2 promoted Gondwanan deglaciation and tropical aridificationObliquity nodes resulted in the Gondwanan glaciation, glacio‐eustatic sea‐level lowerings, and decrease of tropical moisture availability [ABSTRACT FROM AUTHOR]

At the end of the Late Paleozoic Ice Age (LPIA) from late Early Permian to early Late Permian, the global climate was impacted by a prevailing megamonsoon and Gondwanan deglaciation. To better understand the abiotic and biotic responses to Milankovitch-forced climate changes during this time period, multi-element X-ray fluorescence (XRF) geochemistry analyses were conducted on 948 samples from the late Early−late Middle Permian Maokou Formation at Shangsi, South China. The Fe/Ti, S/Ti, Ba/Ti and Ca time series, which were calibrated with an existing “floating” astronomical time scale (ATS), show the entire suite of Milankovitch rhythms including 405 kyr long eccentricity, 128 and 95 kyr short eccentricity, 33 kyr obliquity and 20 kyr precession. Spectral coherency and cross-phase analysis reveals that chemical weathering (monitored by Fe/Ti) and upwelling (captured by S/Ti and Ba/Ti) are nearly antiphase in the precession band, which suggests a contrast between summer and winter monsoon intensities. Strong obliquity signal in the Ba/Ti series is proposed to derive from changes in thermohaline circulation intensity from glaciation dynamics in southern Gondwana. The abundance of foraminifer, brachiopod and ostracod faunas within the Maokou Formation were mainly controlled by the ~1.1 Myr obliquity modulation cycle. The obliquity-forced high-nutrient and oxygen-depleted conditions generally produced a benthic foraminifer bloom, but threatened the brachiopod and ostracod faunas. [ABSTRACT FROM AUTHOR]

In their comment, Smith et al. (2016) discount the astronomical cycle identifications made from Middle Permian cyclostratigraphy in our recent paper (Fang et al. 2015), declaring that we presented defective null models and improper hypothesis tests, and greatly overestimated the statistical significance of cycles. Here we respond in detail to clarify the decisions that were made in our work, and to correct errors and omissions and other misunderstandings arising in their comment. We also discuss the advent of objective methodologies that promise to improve research in cyclostratigraphy in the near future. [ABSTRACT FROM AUTHOR]

The Late Paleozoic Ice Age (LPIA) was the longest-lasting icehouse in the Phanerozoic. Previous studies indicated a climate warming interval in the earliest Permian—an apex of the LPIA. To better understand hydroclimatic changes and carbon cycling within this time interval, we conducted a series of high-resolution geochemical and rock magnetic analyses, including magnetic measurements (e.g., magnetic susceptibility, anhysteretic remanent magnetization, hysteresis loops, temperature-dependent susceptibility), ratio of iron to potassium (Fe/K), and carbonate carbon isotope (δ13C carb) from a deep-marine section in South China. Calibrated to the published astronomical time scale, a negative δ13C carb excursion (−1‰) was identified during 298.4–297.9 Ma, and it was time-equivalent with the warming interval, recognized by a decrease in conodont apatite oxygen isotopes in South China, low-latitude sea-level transgression, and high-latitude deglaciation. The negative δ13C carb excursion also coincided with a magmatic pulse of the Skagerrak-Centered Large Igneous Province (LIP), indicating that the perturbation in carbon cycling is likely associated with the release of volcanic CO 2. Furthermore, cyclostratigraphic analysis on multiple paleoclimatic proxies, including ferrimagnetic susceptibility, gamma-ray, and Fe/K, suggested that the negative excursion of δ13C carb also overlapped with the maximum of the eccentricity cycle. It implied that orbital configurations may amplify the feedback of the LIP, causing this short-term warming interval. • High-resolution carbon isotope and magnetic record in the earliest Permian. • Transient climate warming interval is documented in the earliest Permian. • LIP and orbital forcing were critical drivers of the earliest Permian warming. [ABSTRACT FROM AUTHOR]

• The Tuva–Mongol and Amuria blocks were at low latitudes during 330-315 Ma. • The Boreal Realm likely extended into equatorial regions at 330 Ma. • The Boreal Realm developed in a wide northern temperate zone during 330-315 Ma. Fossil organisms of the Boreal Realm in the Tuva–Mongol Block (TMB) and Amuria Block (AMB) are commonly thought to have lived at mid to high latitudes during the Carboniferous Period; however, reliable paleomagnetic constraints have not been available previously to test this hypothesis. Here we report newly obtained combined paleomagnetic and geochronological results from the Upper Mississippian Gunbayan Formation in the AMB and the Lower Pennsylvanian Altan-Ovoo Formation in the TMB. Zircon U–Pb dating of tuff beds from the Gunbayan and Altan-Ovoo formations yield ages of 331.0 ± 2.7 and 315.5 ± 2.4 Ma, respectively. A total of 263 paleomagnetic specimens underwent stepwise thermal demagnetization. After removing the viscous remanent magnetizations of the recent geomagnetic field, stable high-temperature components (HTCs), carried by magnetite, were successfully acquired from 240 specimens. The HTCs of the Gunbayan Formation passed a fold test and a reversal test, and those of the Altan-Ovoo Formation passed a fold test, suggesting that they represent primary remanence magnetizations. We used the elongation/inclination method to test and correct for all the HTC directions of the clastic rocks of the studied formations. Their corresponding paleomagnetic poles are 46.0°N/320.0°E (A = 95 2.0 °) at ca. 330 Ma for the AMB and 43.5°N/355.9°E (A = 95 2.9 °) at ca. 315 Ma for the TMB. The updated paleomagnetic database indicates with certainty that both the TMB and the AMB were located in northern hemisphere low-latitude regions and close to the equator at ca. 330 Ma, suggesting that the Boreal Realm might have extended into the equatorial region at the onset of the large ice age of the Carboniferous. The paleobiogeographic characteristics and distribution of climate-sensitive lithologies indicate that this realm occupied a wide northern temperate belt during 330–315 Ma. [ABSTRACT FROM AUTHOR]