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The chaotic behavior of the Solar System prevents the prediction of the precise evolution of the planetary secular frequencies. Here we use four cyclostratigraphic sequences, ∼259 Ma Wujiaping Formation, ∼455 Ma Pingliang Formation, ∼655 Ma Datangpo Formation and ∼2,465 Ma Dales Gorge Member, and Bayesian inversion to provide powerful geological constraints to this problem. The inversion provides constraining estimates for the Solar System fundamental secular frequencies g1, g2, g3, g4, and g5, and the Earth's precession rate k from 105.26 ± 2.68 (2σ) arcseconds/year at ∼2,465 Ma to 55.86 ± 2.60 (2σ) arcseconds/year at ∼259 Ma. Stochastic monotone interpolation enables the reconstruction of Earth‐Moon distance from 2.5 billion years to the present. Calculation of tidal dissipation supports the ocean model before 1.4 Ga, but is outside the error range after ∼1.8 Ga, suggesting lower tidal dissipation in the early Proterozoic Eon, and a possible high value in the early Paleozoic. Plain Language Summary: The chaotic history of the Solar System imposes unknown uncertainties on the fundamental secular frequencies of the planets over most of geologic time. This is complicated by a lack of knowledge about the evolution of Earth‐Moon distance, Earth's length of day and tidal dissipation. Geological evidence provides powerful constraints on all of these parameters. To shed light on the parameters, here we carry out Bayesian inversion of fundamental secular frequencies and Earth precession rate on four cyclostratigraphic sequences, and stochastic monotone interpolation to reconstruct Earth‐Moon distance from 2.5 billion years ago to present. From these results we estimate the Earth's tidal dissipation variation, which we compare with theoretical models. Our results provide critical geological constraints for paleotidal simulation, and shine a light on the unique potential of cyclostratigraphy to constrain Earth‐Moon system history across geologic time. Key Points: We obtain new estimates of Earth‐Moon and Solar System dynamical parameters from cyclostratigraphy at four ages from ∼2.5 Ga to ∼259 MaWe interpolate Earth‐Moon distances inferred from the cyclostratigraphy to reconstruct a continuous history from ∼2.5 Ga to the presentWe estimate Earth's tidal dissipation variations from ∼2.5 Ga to the present [ABSTRACT FROM AUTHOR]

A combined paleomagnetic and geochronological study was conducted on the red beds of the Zhesi Formation (ZSF) in the Xilinhot–Songliao Block (XSB) and the andesites and sandstones of the Qingfengshan Formation (QFF) in the North China Block (NCB). The ZSF tuffs and the QFF andesites were dated to 265.3 ± 1.8 Ma and 254.8–257.1 Ma, respectively, using the zircon U–Pb laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) method. A total of 246 paleomagnetic samples were subjected to stepwise thermal demagnetization. After removal of the low‐temperature viscous components acquired in the recent geomagnetic field, stable high‐temperature components (HTCs) were isolated from most samples. The HTC of the ZSF passed a fold test, and the HTC of the QFF passed both fold and reversal tests, indicating their primary origins. The corresponding paleomagnetic poles are 57.4°N/342.0°E (A95 = 4.3°) for the XSB at ~265 Ma and 54.3°N/20.2°E (A95 = 3.3°) for the NCB at ~255 Ma. Comparison of high‐quality Permian paleomagnetic poles of the XSB and NCB reveals a latitudinal convergence and relative rotation between them that led to a scissors‐like closure of the Solonker Ocean from west to east between ~265 and ~246 Ma, which controlled the mixing of the Cathaysian and Angara floras in space and time. The XSB and NCB moved rapidly northward between ~265 and ~255 Ma, which probably accelerated the end‐Guadalupian mass extinction in East Asia. Key Points: New Middle–Late Permian paleomagnetic data were obtained from Inner Mongolia on both sides of the Solonker Suture (SLS)The SLS is formed in a scissors‐like collision from west to east during 265–246 Ma, controlling the mixing of the Cathaysian and Angara florasThe East Asian blocks drifted rapidly northward during 265–255 Ma and probably accelerated the end‐Guadalupian mass extinction in East Asia [ABSTRACT FROM AUTHOR]

The Late Ordovician Pingliang Formation in the Guanzhuang section, located in the south‐western Ordos Basin, North China, contains several K‐bentonite layers, which are important for understanding the tectonic evolution of the south‐western Ordos Basin. This study provides new geochemical and SIMS U–Pb geochronological data for the K‐bentonites to establish the Ordovician high‐resolution chronostratigraphic framework for the Ordos Basin and to provide temporal constraints of major volcanic–magmatic activity. K‐bentonites in the succession yield U–Pb zircon ages of 457.6 ± 3.8 Ma and 454.8 ± 3.8 Ma (2σ analytical uncertainty), showing a depositional age in the Sandbian Stage (Late Ordovician). The result is consistent with the biostratigraphic and astrochronologic framework, achieving the intercalibration of different dating methods. The discrimination diagrams of whole‐rock Na2O+K2O against SiO2 and Zr/TiO2 against Nb/Y and Th/Yb against Nb/Yb and Th‐Hf‐Ta indicate that the K‐bentonites have obvious arc affinities. Based on the geological background, we conclude that the K‐bentonites in the south‐western Ordos Basin were mainly deposited during the development of the North Qilian‐North Qinling volcanic arc in the Sandbian. [ABSTRACT FROM AUTHOR]

The Middle Triassic Luoping biota represents a full recovery of marine ecosystem after the Permian-Triassic mass extinction, yet the temporal duration and exceptional preservation mechanism of the Luoping biota remain uncertain. Here, zircon geochronology and cyclostratigraphy analysis are carried out on an Anisian (Middle Triassic) Guanling Formation succession yielding the Luoping biota at the Xiangdongpo section in Yunnan Province, South China. The sensitive high-resolution ion microprobe (SHRIMP) zircon U Pb dating of a tuff bed (bed 15) in the strata confirmed an age of 244.5 ± 2.2 Ma for the Luoping biota. Spectral analyses on the elemental proxies for terrestrial flux (K, Ti, Si, Al, and K/Ti) reveal significant sedimentary cycles. The cyclostratigraphy analysis shows persistent cycles of ca. 4.4–5.1 m, 1.7–2.0 m, 0.9–1.2 m, ∼0.5 m, 0.33–0.37 m, and ∼ 0.23 m cycles, which may correspond to the orbitally forced sedimentary cycles caused by short-eccentricity (∼100 kyr), obliquity (∼32.9 kyr), precession (∼20 kyr), and sub-Milankovitch cycles (∼10 kyr, ∼8.3 kyr, and ∼ 5 kyr). Based on these results, we estimate the duration of the Luoping biota to be ∼340 ± 71 kyr. The intensified monsoonal climate during eccentricity maxima modulated large amplitude of variations of ∼5 kyr quarter precession, ∼10 kyr half precession, and ∼ 20 kyr precession cycles, led to high terrigenous discharge and strengthened upwelling, which fueled the primary productivity in surface water due to high nutrient input into the Luoping area. We propose that this process enhanced oxygen consumption in the water column, triggered anoxia of bottom water, and promoted the exceptional preservation of the Luoping biota. • Zircon U Pb SHRIMP dating of a tuff bed reveals the formation age of the Luoping biota in the Middle Triassic. • The 100 ka-tuned floating astronomical age scale provides new constraints on the duration of the Luoping biota. • Our results illustrate the relationship between orbital scale variability of monsoon and preservation of the Luoping biota. [ABSTRACT FROM AUTHOR]

Milankovitch cycles are quasi-periodic fluctuations in insolation forced by variations in the Earth's astronomical parameters, inducing climate change, and in turn affecting sedimentation and the formation of cyclostratigraphy. Astronomical calibration of the cyclostratigraphy can be exploited as a high-resolution (0.02–0.4 Myr) astronomical time scale (ATS), facilitating the reconstruction of Earth's evolutionary history. The ATS is already an important geochronometer for the Cenozoic and Mesozoic eras, however, the ATS for the Paleozoic Era has yet to be fully constructed. Radioisotopic age-calibrated Milankovitch cycles have been detected in Paleozoic strata, linked to the hierarchy of sedimentary cycles deposited in the continental, paralic, and marine environments. The orbital eccentricity metronome (i.e., 405-kyr cycle) has already been used to construct the ATS for the timing of Paleozoic geological and climatic events. Here, we review Paleozoic cyclostratigraphy and develop a provisional ATS from published paleoclimatic proxy time series, which results in revisions to the timing of key geological events in the Paleozoic Era. [ABSTRACT FROM AUTHOR]

The breakup of eastern Gondwana is among the hottest topics in the Earth sciences because of its effect on global climate during the Jurassic‐Cretaceous, its influence on the evolution of life, and its importance to paleogeographic reconstruction. To better constrain the Jurassic and Cretaceous paleogeographic position of the Tethyan Himalaya and the breakup of eastern Gondwana, a combined paleomagnetic and geochronological study was performed on the Zhela and Weimei Formations lava flows, dated at ~138–135 Ma, in the Luozha area of the eastern Tethyan Himalaya. Both positive fold and reversal tests together with a maximum grouping at 100% unfolding indicate that the characteristic remanent magnetization directions are primary magnetizations acquired before folding. The tilt‐corrected directions yielded a paleopole at 0.9°N, 293.4°E with A95 = 7.0° and a corresponding paleolatitude of 53.5°S ± 7.0°S for the Luozha sampling area (28.9°N, 91.3°E), validating that the original erupted position of the Zhela and Weimei Formations lava flows was located in the center of the Kerguelen mantle plume. Our new results, together with the published paleomagnetic, geochronological, and geochemical results, demonstrate that the Comei‐Bunbury large igneous province originated from the Kerguelen mantle plume. The temporal and spatial relationships between the Comei‐Bunbury large igneous province and the Kerguelen mantle plume indicate that eastern Gondwana initially rifted at ~147 Ma and that the Indian Plate fully separated from the Australian‐Antarctic Plate before ~124 Ma. Key Points: The Luozha sampling area was located at ~53.5 degrees south plus‐minus 7.0 degrees south at ~138‐135 MaThe Comei‐Bunbury large igneous province (LIP) originated from the Kerguelen mantle plumeEastern Gondwana initially rifted at ~147 Ma, and the Indian Plate fully separated from the Australian‐Antarctic Plate before ~124 Ma [ABSTRACT FROM AUTHOR]

The Late Paleozoic Ice Age (ca. 335–260 Ma, LPIA) has long been considered as an analogy for the Cenozoic ice age since the Oligocene. The impact of astronomical forcing on the LPIA glaciation has been hampered due to the low-resolution (multi-million year scale) time framework. In the present study, high-resolution cyclostratigraphy based on magnetic susceptibility (MS), covering the Serpukhovian to late Moscovian icehouse climate, has been investigated in the Luokun section of South China. Power spectral analysis of the MS series reveals 3.44–4 m, 0.8–1.07 m, 0.3–0.32 m, and 0.17–0.19 m thick sedimentary cycles. Based on the available biostratigraphic constraints, calibrating the 3.44–4 m cycles to the 405 kyr eccentricity cycles indicates short eccentricity (136 and 100 kyr), short obliquity (34 kyr), and precession (19 and 15.9 kyr) orbital bands in addition to long eccentricity (405 kyr) band. We assigned the basal Serpukhovian and Moscovian stages in Luokun with the numerical ages from Geological Time Scale 2012 to construct two floating time scales ranging from 331.55 ± 0.5 Ma to 323.2 ± 0.5 Ma, and from 315.34 ± 0.35 Ma to 310.17 ± 0.35 Ma, respectively. The modulation of main obliquity ( s 4 – s 3 term) has a main periodicity of ∼1200 kyr. The modulation of ∼100 kyr eccentricity ( g 4 – g 3 term) shows a main periodicity of ∼2400 kyr with subordinate periodicities of ∼1620 and ∼1200 kyr for the Serpukhovian, and a main periodicity of ∼1600 kyr for the Moscovian. They may provide the geological evidence for a chaotic resonance associated with interactions between the orbits of Mars and the Earth in the Carboniferous. A duration of 7.68 ± 0.15 Myr was estimated for the Serpukhovian Stage. Eight higher accumulation rate events due to glacioeustatic drawdown were temporally constrained, and show close correspondence to far-field and near-field reconstructions of the LPIA glaciation. Glacioeustasy was paced with 405-kyr-long eccentricity and 1.2-Myr obliquity amplitude cycles during the Serpukhovian and Moscovian stages, likely indicating the nature in the warmer icehouse world similar to that of the Oligocene to Pliocene. [ABSTRACT FROM AUTHOR]

Abstract: The mass extinction at the end of Permian was followed by a prolonged recovery process with multiple phases of devastation–restoration of marine ecosystems in Early Triassic. The time framework for the Early Triassic geological, biological and geochemical events is traditionally established by conodont biostratigraphy, but the absolute duration of conodont biozones are not well constrained. In this study, a rock magnetic cyclostratigraphy, based on high-resolution analysis (2440 samples) of magnetic susceptibility (MS) and anhysteretic remanent magnetization (ARM) intensity variations, was developed for the 55.1-m-thick, Early Triassic Lower Daye Formation at the Daxiakou section, Hubei province in South China. The Lower Daye Formation shows exceptionally well-preserved lithological cycles with alternating thinly-bedded mudstone, marls and limestone, which are closely tracked by the MS and ARM variations. Power spectral, wavelet and amplitude modulation (AM) analyses of the ARM and MS series reveal strong evidence for the presence of Milankovitch to sub-Milankovitch frequencies dominated by precession index signal and 4–5ka cycles. Cycles expressed by variations in MS and ARM were likely controlled by changes in the input of fine-grained detrital magnetite, which in turn may have been driven by astronomically induced changes in monsoon intensity in the equatorial eastern Paleotethys during the Early Triassic greenhouse period. On the basis of the 100-ka tuning results, the astronomically constrained duration of the Induan stage is 1.16Ma, with the Griesbachian and Dienerian substages of 490ka and 670ka, respectively. The new astronomical time scale also provides time constraints for the conodont and bivalve biozones and the carbonate carbon isotope (δ 13C) records of the Lower Triassic Daye Formation. Time constraints for the conodont biozones include 34ka for Hindeodus parvus, 24ka for Isarcicella staschei–I. isarcica, 366ka for Neogondolella planata–Ng. carinata, 66ka for Neogondolella discreta, 255ka for Neospathodus kummeli and 415ka for Neospathodus dieneri. The duration for the negative δ 13C shift from high δ 13C values near the Indun/Olenekian boundary to the lowest value in the Early Smithian is estimated as 430ka. Global comparison indicates that Milankovitch and 4–5ka sub-Milankovitch forcing depositional rhythms may have been common in tropical and sub-tropical carbonate platforms during the Early and Middle Triassic time. The ultimate control on the 4–5ka cycles may have been millennial-scale fluctuations in solar insolation. [Copyright &y& Elsevier]

Carbonate dissolution in subduction zones transfers surface carbon to the mantle and plays an important role in regulating global carbon cycles through geologic time. Petrological observations and thermodynamic models predict substantial dissolution of subducting carbonates induced by slab-derived fluids at arc mantle depths, but this dissolution process has rarely been verified by existing geochemical tracers. In this paper we show that zinc and magnesium isotopes can serve as such tracers through a comparative study on carbonate-bearing and carbonate-free sediments from the South China Sea and the Philippine Sea that are going to be subducted. Leaching experiments are further performed to characterize the isotopic difference between dissolved carbonates and silicate components in sediments. Bulk carbonate-bearing sediments and carbonate-free sediments surprisingly have indistinguishable δ66Zn (0.26 ± 0.04‰ versus 0.25 ± 0.04‰), but the former display systematically lower δ26Mg (−0.85‰ to −0.17‰, n = 10) than the latter (−0.26‰ to +0.13‰, n = 13). Leaching experiments show that dissolved carbonates have much higher δ66Zn (0.82 ± 0.26‰) and lower δ26Mg (−2.70 ± 0.35‰) compared with the silicate residues (δ66Zn = 0.21 ± 0.06‰; δ26Mg = −0.06 ± 0.14‰). These results indicate that the presence of carbonate components has insignificant influence on Zn isotopic compositions of bulk sediments but prominent influence on their Mg isotopic compositions. In this respect, the final fate of carbonates in subducting sediments can be tracked by a combined Mg and Zn isotope analysis on mantle-derived magmas. For instance, bulk carbonate-bearing sediment addition (i.e., no carbonate dissolution) during subduction would produce low δ26Mg but normal δ66Zn values (i.e., Mg-Zn isotopic "decoupling") in mantle-derived magmas. By contrast, if carbonate dissolution occurs during subduction, the high δ66Zn and low δ26Mg (i.e., Mg-Zn isotopic "coupling") signals of dissolved carbonates will be transferred to the sources of mantle-derived magmas. We test this application for a Cenozoic subduction-related, arc-like volcanic exposure from Tengchong, Southwestern China and find significant Mg-Zn isotopic coupling, which demonstrates carbonate dissolution during Indian Oceanic slab subduction. Our results also shed constraints on the amount of dissolved carbonates in the sub-arc mantle. Available data reveal the absence of high δ66Zn and low δ26Mg in global arc lavas, for which we suggest to be the result of a relatively low proportion (<20%) of dissolved calcium carbonates in the sub-arc mantle. [ABSTRACT FROM AUTHOR]

The article presents a study which analyses the new Zircon SHRIMP U-Pb ages of the Langjiu formation volcanic rocks in the Shiquanhe Area in Western Lhasa Terrane. Topics include distribution of potassic and ultrapotassic rocks, geochronological study on the Langjiu Formation volcanic rocks, and magmatic activity of the Linzizong group volcanic rocks.

The Hangenberg Event was one of the most significant mass extinctions accompanied by large-scale climate changes at the end of the Devonian period. Lack of precise and accurate geochronological constraints in the eastern Paleotethys has hindered a high-resolution global correlation of the Hangenberg Event. Here, we report the U–Pb dates of zircons from the bentonite samples intercalated with strata recording the Hangenberg Event in the Muhua region, Guizhou, South China, using both sensitive high-resolution ion microprobe (SHRIMP) and chemical abrasion - isotope dilution - thermal ionization mass spectrometry (CA-ID-TIMS) methods. A bentonite within the Hangenberg Event strata in the Muhua area was dated at 360.47 ± 0.68 Ma by CA-ID-TIMS, which is more precise than the results obtained by SHRIMP methods (361.5 ± 2.9 Ma and 359.8 ± 1.5 Ma). Thus, we propose that the Hangenberg Event took place at 360.47 ± 0.68 Ma in South China, based on the first precise CA-ID-TIMS zircon age from the Daposhang section. The age obtained from South China for the Devonian–Carboniferous boundary overlaps with that in Geologic Time Scale 2020, within the total uncertainties. • New U-Pb CA-ID-TIMS and SHRIMP zircon dates are reported from two bentonites around the Hangenberg Event in South China. • The Hangenberg Event occurred at 360.47 ± 0.68 Ma in the Daposhang section. • New age for Devonian–Carboniferous boundary overlaps with that in GTS 2020. [ABSTRACT FROM AUTHOR]

In Liaoning Province, Northeastern China, the Early Cretaceous Jehol Biota records significant evolution and radiation of fauna in terms of diversity, abundance and complexity. The alluvial-to-fluvial Lujiatun and lacustrine Jianshangou beds of the lower Yixian Formation yield exceptionally well-preserved three-dimensional and articulated dinosaur and mammal fossils, and two-dimensional primitive birds/feathered dinosaurs, respectively. Published 40Ar/39Ar ages for the two fossil beds have uncertainties of ± 0.4 to 1.0 Ma (± 2 σ analytical uncertainty), and these reflect the measurement of large, and potentially heterogeneous, populations of feldspar crystals. More precise constraints on the timing and duration of biological radiation recorded by this sequence can further quantify evolutionary patterns and rates of diversification of important Early Cretaceous animals and plants. Single crystal 40Ar/39Ar fusion experiments on sanidine from intercalated ash beds yield dates that constrain the deposition of the Jianshangou and Lujiatun fossil beds to between 125.374 ± 0.085 and 125.572 ± 0.120 Ma, and 125.541 ± 0.099 and 125.793 ± 0.127 Ma, respectively. These ages indicate that the lower part of Jianshangou fossil bed was deposited nearly contemporaneously with the Lujiatun fossil bed. Thus, mass mortality events reflected by dinosaur fossil concentrations in the Lujiatun fossil bed and feathered dinosaur/primitive bird fossils in the Jianshangou fossil bed were nearly coeval and short-lived. These 40Ar/39Ar ages, combined with astrochronologic and paleomagnetic results from the lacustrine sediments in the Jianshangou fossil bed, not only refine the duration and rapid radiation of primitive birds and feathered dinosaurs in the deposit, but also suggest that the distribution of magnetic polarity chron boundaries within the Barremian stage in the current geologic time scale (GTS 2020) requires a revision. • The lower part of JSG and LJT fossil member deposited nearly contemporaneously. • Strata preserving primitive birds/feathered dinosaurs paced by short eccentricity. • Duration of biological radiations recorded by the 11 m strata is ∼460 to 610 kyr. • Timing of magnetic boundaries within Barremian stage in GTS 2020 requires revision. [ABSTRACT FROM AUTHOR]

The Cretaceous continental sedimentary records are essential to our understanding of how the terrestrial geologic and ecologic systems responded to past climate fluctuations under greenhouse conditions and our ability to forecast climate change in the future. The Songliao Basin of Northeast China preserves a near-complete, predominantly lacustrine, Cretaceous succession, with sedimentary cyclicity that has been tied to Milankocitch forcing of the climate. Over 900 meters of drill-core recovered from the Upper Cretaceous (Turonian to Campanian) of the Songliao Basin has provided a unique opportunity for detailed analyses of its depositional and paleoenvironmental records through integrated and high-resolution cyclostratigraphic, magnetostratigraphic and geochronologic investigations. Here we report high-precision U–Pb zircon dates (CA-ID-TIMS method) from four interbedded bentonites from the drill-core that offer substantial improvements in accuracy, and a ten-fold enhancement in precision, compared to the previous U–Pb SIMS geochronology, and allow a critical evaluation of the Songliao astrochronological time scale. The results indicate appreciable deviations of the astrochronologic model from the absolute radioisotope geochronology, which more likely reflect cyclostratigraphic tuning inaccuracies and omitted cycles due to depositional hiatuses, rather than suspected limitations of astronomical models applied to distant geologic time. Age interpolation based on our new high-resolution geochronologic framework and the calibrated cyclostratigraphy places the end of the Cretaceous Normal Superchon (C34n–C33r chron boundary) in the Songliao Basin at 83.07 ± 0.15 Ma . This date also serves as a new and improved estimate for the global Santonian–Campanian stage boundary. [ABSTRACT FROM AUTHOR]