Explore the vast range of titles available.

The long-term history of the Earth—Moon system as reconstructed from the geological record remains unclear when based on fossil growth bands and tidal laminations. A possibly more robust method is provided by the sedimentary record of Milankovitch cycles (climatic precession, obliquity, and orbital eccentricity), whose relative ratios in periodicity change over time as a function of a decreasing Earth spin rate and increasing lunar distance. However, for the critical older portion of Earth’s history where information on Earth—Moon dynamics is sparse, suitable sedimentary successions in which these cycles are recorded remain largely unknown, leaving this method unexplored. Here we present results of cyclostratigraphic analysis and high-precision U—Pb zircon dating of the lower Paleoproterozoic Joffre Member of the Brockman Iron Formation, NW Australia, providing evidence for Milankovitch forcing of regular lithological alternations related to Earth’s climatic precession and orbital eccentricity cycles. Combining visual and statistical tools to determine their hierarchical relation, we estimate an astronomical precession frequency of 108.6 ± 8.5 arcsec/y, corresponding to an Earth—Moon distance of 321,800 ± 6,500 km and a daylength of 16.9 ± 0.2 h at 2.46 Ga. With this robust cyclostratigraphic approach, we extend the oldest reliable datum for the lunar recession history by more than 1 billion years and provide a critical reference point for future modeling and geological investigation of Precambrian Earth—Moon system evolution.

Cretaceous strata are widely distributed across China and record a variety of depositional settings. The sedimentary facies consist primarily of terrestrial, marine and interbedded marine-terrestrial deposits, of which marine and interbedded facies are relatively limited. Based a thorough review of the subdivisions and correlations of Cretaceous strata in China, we provide an up-to-date integrated chronostratigraphy and geochronologic framework of the Cretaceous system and its deposits in China. Cretaceous marine and interbedded marine-terrestrial sediments occur in southern Tibet, Karakorum, the western Tarim Basin, eastern Heilongjiang and Taiwan. Among these, the Himalayan area has the most complete marine deposits, the foraminiferal and ammonite biozonation of which can be correlated directly to the international standard biozones. Terrestrial deposits in central and western China consist predominantly of red, lacustrine-fluvial, clastic deposits, whereas eastern China, a volcanically active zone, contains clastic rocks in association with intermediate to acidic igneous rocks and features the most complete stratigraphic successions in northern Hebei, western Liaoning and the Songliao Basin. Here, we synthesise multiple stratigraphic concepts and charts from southern Tibet, northern Hebei to western Liaoning and the Songliao Basin to produce a comprehensive chronostratigraphic chart. Marine and terrestrial deposits are integrated, and this aids in the establishment of a comprehensive Cretaceous chronostratigraphy and temporal framework of China. Further research into the Cretaceous of China will likely focus on terrestrial deposits and mutual authentication techniques (e.g., biostratigraphy, chronostratigraphy, magnetostratigraphy and cyclostratigraphy). This study provides a more reliable temporal framework both for studying Cretaceous geological events and exploring mineral resources in China.

The modern pattern of the Asian monsoon is thought to have formed around the Oligocene/Miocene transition and is generally attributed to Himalaya—Tibetan Plateau (H—TP) uplift. However, the timing of the ancient Asian monsoon over the TP and its response to astronomical forcing and TP uplift remains poorly known because of the paucity of well-dated high-resolution geological records from the TP interior. Here, we present a precession-scale cyclostratigraphic sedimentary section of 27.32 to 23.24 million years ago (Ma) during the late Oligocene epoch from the Nima Basin to show that the South Asian monsoon (SAM) had already advanced to the central TP (32°N) at least by 27.3 Ma, which is indicated by cyclic arid–humid fluctuations based on environmental magnetism proxies. A shift of lithology and astronomically orbital periods and amplified amplitude of proxy measurements as well as a hydroclimate transition around 25.8 Ma suggest that the SAM intensified at ~25.8 Ma and that the TP reached a paleoelevation threshold for enhancing the coupling between the uplifted plateau and the SAM. Orbital short eccentricity-paced precipitation variability is argued to be mainly driven by orbital eccentricity-modulated low-latitude summer insolation rather than glacial-interglacial Antarctic ice sheet fluctuations. The monsoon data from the TP interior provide key evidence to link the greatly enhanced tropical SAM at 25.8 Ma with TP uplift rather than global climate change and suggest that SAM’s northward expansion to the boreal subtropics was dominated by a combination of tectonic and astronomical forcing at multiple timescales in the late Oligocene epoch.

Continental hydroclimate dynamics and its responses during the Middle Eocene Climatic Optimum (MECO, ∼40 Ma) remain largely unexplored. Here, we present high‐resolution multi‐proxy records from four East Asian lake basins that demonstrate precipitation, chemical weathering, and terrestrial input underwent multi‐phase changes during the MECO. Our results identify short‐eccentricity, precession, and half‐precession cycles as significant forcings on Eocene East Asian rainfall intensity, emphasizing their pivotal role in pacing hydroclimate evolution during the MECO. Our results also show that, before and during the early MECO, intensified precipitation enhanced chemical weathering and physical erosion, thereby increasing terrestrial input. At peak MECO, however, chemical weathering peaked despite reduced rainfall, suggesting a shift in the dominant weathering mechanism. We propose that extensive weathering and erosion during preceding warm and wet phases exposed large areas of fresh silicate surfaces, enabling temperature‐driven weathering during peak MECO. This process likely consumed substantial atmospheric CO2, ultimately terminating the event.

The Hirnantian period, making the end of the Ordovician with significant mass extinctions and large ice‐sheets, is a critical interval for studying paleoclimate variations. This research represents the first cyclostratigraphic study of this period, utilizing high‐resolution (1 mm sampling rate) geochemical data from the ∼7‐m thick SH‐1 drill core, capturing the latest Ordovician glaciation. Our analysis identifies the presence of Milankovitch cycles with periods of 17–21, ∼33, and ∼100‐kyr, suggesting an optimal sedimentation rate of 3.1 m/Myr. Notably, we detected signals of millennial‐scale variability, aligning with the ∼1.5‐kyr Dansgaard‐Oeschger and ∼2.4‐kyr Hallstatt heliomagnetic cycles, even in deposits lacking visible laminae alternation. This finding bolsters the hypothesis of an external origin for these millennial‐scale features. Additionally, our reconstruction of sea‐level variations, using principal component analysis and sedimentary noise modeling, reveals two intervals of sea‐level fall and one sea‐level rise, linked to an astronomical forcing cycle of ∼1.2‐Myr. The obliquity band power‐total power ratios correspond to ∼1.2‐Myr periodicities for s4‐s3 term. The synchronization of ∼1.2‐Myr cycle minimum with a sea‐level drop (low PC1 value) suggests that glacio‐eustatic variations were influenced by ∼1.2‐Myr obliquity modulation cycles. This research enhances our understanding of glacio‐eustasy during the latest Ordovician from an astronomical perspective, offering valuable insights into the interplay between orbital cycles and Earth's paleoclimate. Key Points Millennial‐scale cycles have been detected based on five high‐resolution proxy series Millennial‐scale cycle preserved in the Hirnantian was linked to the D‐O and Hallstatt cycle ∼1.2‐Myr PC1 filter revealed one rise and two falls of sea‐level during Hirnantian

High‐precision ID‐TIMS U‐Pb zircon ages for 12 interstratified tuffs and tonsteins are used to radiometrically calibrate the detailed lithostratigraphic, cyclostratigraphic, and biostratigraphic framework of the Carboniferous Donets Basin of eastern Europe. Chemical abrasion of zircons, use of the internationally calibrated EARTHTIME mixed U‐Pb isotope dilution tracer, and improved mass spectrometry guided by detailed error analysis have resulted in an age resolution of <0.05%, or ∼100 ka, for these Carboniferous volcanics. This precision allows the resolution of time in the Milankovitch band and confirms the long‐standing hypothesis that individual high‐frequency Pennsylvanian cyclothems and bundles of cyclothems into fourth‐order sequences are the eustatic response to orbital eccentricity (∼100 and 400 ka) forcing. Tuning of the fourth‐order sequences in the Donets Basin to the long‐period eccentricity cycle results in a continuous age model for the Middle to Late Pennsylvanian (Moscovian‐Kasimovian‐Ghzelian) strata of the basin and their record of biological and climatic changes through the latter portion of the late Paleozoic Ice Age. Detailed fusulinid and conodont zonations allow the export of this age model to sections throughout Euramerica. Additional ages for Mississippian strata provide among the first robust radiometric calibration points within this subperiod and result in variable lowering of the base ages of its constituent stages compared to recent global time scale compilations.

Here we present combined radioisotopic dating (U‐Pb zircon) and cyclostratigraphic analysis of the carbon isotope excursion at the Paleocene‐Eocene (P‐E) boundary in Spitsbergen to determine the numerical age of the boundary. Incorporating the total uncertainty from both radioisotopic and cyclostratigraphic data sets gives an age ranging from 55.728 to 55.964 Ma, within error of a recently proposed astronomical age of ∼55.93 Ma. Combined with the assumption that the Paleocene Epoch spans twenty‐five 405 kyr cycles, our new age for the boundary suggests an age of ∼66 Ma for the Cretaceous‐Paleogene boundary. Furthermore, our P‐E boundary age is consistent with the hypothesis that the onset of the Paleocene‐Eocene thermal maximum at the boundary occurred on the falling limb of a 405 kyr cycle, suggesting the event was initiated by a different mechanism to that which triggered the other early Eocene hyperthermals. Key Points New Paleocene‐Eocene boundary age range from 55.728 to 55.964 Ma (95% confidence) New P‐E age suggests the Cretaceous‐Paleogene boundary is ∼66 Ma New P‐E age suggests the PETM had a different trigger from other hyperthermals

High-resolution cyclostratigraphic and sequence stratigraphic analyses are often compromised and lead to incorrect interpretations due to the unavailability or critical, proven errors in the reference Gamma-Ray (GR) and Density (RHOB) logs in hydrocarbon wells. This issue creates operational risks, delays, and costly re-logging procedures, directly impacting reservoir modeling and development decisions. This study presents an innovative, multi-Proxy methodology to address this critical problem by assessing the capability of the Sonic (DT), Neutron (NPHI), and Resistivity (RT) logs as reliable substitutes. The research focuses on three wells (A, B, and C) in the Oligocene to Miocene Asmari Formation of the Dezful Embayment, Southwest Iran. Available logs were analyzed to delineate third- and fourth-order sedimentary sequences based on Inflection Points. Subsequently, several advanced, distinct methods were used for comprehensive validation and the study of astronomical cycles: Spectral Analysis (SA) and Evolutionary Spectral Analysis (ESA) to isolate the influential Milankovitch cycles; Correlation Coefficient (COCO) and Evolutionary Correlation Coefficient (eCOCO) analysis to determine the Sediment Accumulation Rate (SAR); Wavelet Transform Scalogram analysis to identify intense frequency variations and interpret corresponding lithological changes; and Lag-1 Autocorrelation Coefficient (ρ1) to examine sedimentary noise and determine global sea-level trends. The outputs of the substitute logs were compared with the results of the reference GR and RHOB logs to establish their validity. The results strongly confirm the utility of the multi-proxy substitute logs. The DT and NPHI logs demonstrated a high degree of correlation across all analytical methods and reliably identified the third-order sequences. However, the RT log exhibited greater variability, particularly in high-frequency cyclicity (fourth-order) and SAR calculation, which underscores the necessity of a multi-proxy approach. This validated, multi-proxy methodology offers a definitive, cost-effective, and rapid solution for accurate stratigraphic analysis and reservoir characterization in data-scarce or error-prone environments. It allows the petroleum industry to make reliable geological and engineering decisions in the very early stages of interpretation, significantly enhancing informational certainty for exploration and development projects.

Sedimentological records provide the only accessible archive for unraveling Earth’s orbital variations in the remote geological past. These variations modulate Earth’s climate system and provide essential constraints on gravitational parameters used in solar system modeling. However, geologic documentation of midlatitude response to orbital climate forcing remains poorly resolved compared to that of the low-latitude tropics, especially before 50 Mya, the limit of reliable extrapolation from the present. Here, we compare the climate response to orbital variations in a Late Triassic midlatitude temperate setting in Jameson Land, East Greenland (∼43°N paleolatitude) and the tropical low paleolatitude setting of the Newark Basin, with independent time horizons provided by common magnetostratigraphic boundaries whose timing has been corroborated by uranium-lead (U-Pb) zircon dating in correlative strata on the Colorado Plateau. An integrated cyclostratigraphic and magnetostratigraphic age model revealed long-term climate cycles with periods of 850,000 and 1,700,000 y ascribed to the Mars–Earth grand orbital cycles. This indicates a 2:1 resonance between modulation of orbital obliquity and eccentricity variations more than 200 Mya and whose periodicities are inconsistent with astronomical solutions and indicate chaotic diffusion of the solar system. Our findings also demonstrate antiphasing in climate response between low and midlatitudes that has implications for precise global correlation of geological records.

The lithostratigraphic characteristics of the iconic Blue Lias Formation of southern Britain are influenced by sedimentation rates and stratigraphic gaps. Evidence for regular sedimentary cycles is reassessed using logs of magnetic susceptibility from four sites as an inverse proxy for carbonate content. Standard spectral analysis, including allowing for false discovery rates, demonstrates several scales of regular cyclicity in depth. Bayesian probability spectra provide independent confirmation of at least one scale of regular cyclicity at all sites. The frequency ratios between the different scales of cyclicity are consistent with astronomical forcing of climate at the periods of the short eccentricity, obliquity and precession cycles. Using local tuned time scales, 62 ammonite biohorizons have minimum durations of 0.7 to 276 ka, with 94% of them <41 ka. The duration of the Hettangian Stage is ≥2.9 Ma according to data from the West Somerset and Devon/Dorset coasts individually, increasing to ≥3.7 Ma when combined with data from Glamorgan and Warwickshire. A composite time scale, constructed using the tuned time scales plus correlated biohorizon limits treated as time lines, allows for the integration of local stratigraphic gaps. This approach yields an improved duration for the Hettangian Stage of ≥4.1 Ma, a figure that is about twice that suggested in recent time scales.