Ancient Grand Canyon strata record Earth–Moon and Solar System history

Deep within the walls of the Grand Canyon, layered mudstones deposited more than a billion years ago have yielded an extraordinarily rare archive of the ancient Earth–Moon system and the dynamics of the early Solar System. A new study published in Nature Geoscience reports that sedimentary rhythms preserved in the Mesoproterozoic Hakatai Shale, part of the Grand Canyon Supergroup, allow scientists to reconstruct, with unprecedented empirical precision, how the Moon’s distance from Earth, the length of Earth’s day, and the fundamental frequencies of planetary orbits have evolved over deep time. The findings come from a team led by Margriet L. Lantink of the University of Wisconsin–Madison and Utrecht University, together with Athena Eyster of Tufts University, Ilja J. Kocken and Richard E. Zeebe of the University of Hawaiʻi at Mānoa, and Stephen R. Meyers of the University of Wisconsin–Madison.

The research centers on Milanković cycles, the periodic variations in Earth’s orbital eccentricity, axial tilt, and precession that redistribute the sunlight reaching the planet and thereby pace long-term climate change. In the modern Solar System, these cycles operate on well-known timescales, and they have been used to calibrate the geological time scale for the Cenozoic era with remarkable accuracy. Extending that approach into the Precambrian, however, has been hampered by a fundamental problem: numerical models of the Solar System’s orbital motion become chaotic and lose predictive power over tens of millions of years, and no astronomical solution can currently be trusted beyond roughly the last 100 million years. For intervals more than a billion years in the past, scientists have had to rely on theory alone to estimate how orbital frequencies differed from today’s values.

Sedimentary rocks offer a way around this limitation. When climate cycles driven by orbital variations imprint regular patterns on accumulating sediment—alternations between more resistant and more recessive beds, for example, or rhythmic changes in grain size and composition—the resulting cyclostratigraphy can be read as a recording of the astronomical forcing that produced it. The Hakatai Shale, deposited in shallow-water settings roughly 1.4 to 1.1 billion years ago during the Mesoproterozoic era, preserves such rhythms in striking detail. The team logged and analyzed stratigraphic sections at Red Canyon and Tapeats Creek within Grand Canyon National Park, conducting fieldwork under permit from the National Park Service, and measured the thickness and character of successive sedimentary cycles with centimeter-scale resolution.

The key to interpreting these rhythms lies in the physics of the Earth–Moon system. Tidal friction, the braking effect of lunar tides on Earth’s rotation, has steadily slowed the planet’s spin over geological time while pushing the Moon gradually farther away. As the day lengthens, the frequency of the climatic precession cycle—the wobble in Earth’s axis that changes how seasons align with the planet’s position around the Sun—changes in a predictable way. Because the precession signal modulates the amplitude of the eccentricity cycle, sedimentary records that capture both can be used to solve for the precession constant and, from it, the ancient Earth–Moon distance and length of day. This approach, known as TimeOpt and its Bayesian extension TimeOptBMCMC, was applied to the Hakatai Shale using the Astrochron software package, with 100,000 Monte Carlo samples used to constrain the statistical uncertainty of the reconstruction.

The analysis of the Tapeats Creek composite record, corrected for variations in sediment thickness, revealed a coherent suite of astronomical signals. The team identified cycles corresponding to climatic precession, orbital eccentricity, and obliquity, and used the ratios among them to test which cyclostratigraphic interpretation best fit the data. Among three competing interpretations of the dominant spectral peaks, the preferred option yielded sedimentation rates of a few centimeters per thousand years—values consistent with the quiet, low-energy depositional environments inferred independently from the rock’s lithology, which includes reworked microbial mat fabrics, wind-blown quartz grains, and pseudomorphs after evaporite minerals such as gypsum and anhydrite.

Beyond confirming that Milanković forcing operated in the Mesoproterozoic, the record delivered a surprise. The relative amplitudes of the astronomical forcing frequencies, particularly obliquity—the tilt of Earth’s spin axis—showed anomalous patterns compared with what present-day dynamics would predict. In the spectra of the Hakatai Shale, the strength of individual obliquity-related peaks shifted between different stratigraphic intervals in ways that mirror the behavior of state-of-the-art deep-time astronomical models, specifically the ZB23 solutions developed by Zeebe and colleagues, which extend orbital calculations back 3.5 billion years. In those models, the dominance of particular obliquity cycles changes through time as secular resonances among the planets drift in and out of critical configurations.

One such configuration involves the resonance angle associated with the motions of Mars and the inner planets, which can transiently disrupt the dominant obliquity cycle. Another involves a secular resonance that interferes with the main eccentricity cycle linked to the orbital frequencies of Earth and Jupiter. The Hakatai spectra show amplitude trends—weak expression of one eccentricity peak, enhanced power in a particular obliquity band—that are consistent with the models’ predictions for conditions around 1.2 billion years ago, including the possible influence of a resonance in which combinations of planetary orbital frequencies and Earth’s axial precession frequencies nearly coincide. The authors note that these patterns could also reflect a nonlinear climate response, in which interactions between multiple forcing frequencies generate combination tones that appear in the sedimentary record at sums and differences of the original periods.

Either interpretation carries weighty implications. If the amplitude anomalies record shifts in secular Solar System resonances, then the Grand Canyon strata provide the first empirical evidence from the rock record for how the gravitational architecture of the planetary system has changed over more than a billion years, complementing purely numerical approaches that are limited by chaos. If, instead, the signals arise from nonlinear climate dynamics, they illuminate how the Precambrian climate system responded to astronomical forcing in an atmosphere and ocean very different from today’s, before the rise of complex life and with substantially different greenhouse gas inventories. Distinguishing between these possibilities is a central goal of ongoing work, and the Bayesian inverse modeling framework applied here is designed to weigh such alternatives quantitatively.

The study builds on a growing effort to use geology as a probe of Solar System dynamics, sometimes described as mapping Solar System chaos with the geological record. Previous work by members of the team demonstrated that Milankovitch cycles preserved in 2.46-billion-year-old banded iron formations constrain the Earth–Moon system in the Paleoproterozoic, and theoretical studies have traced how tidal evolution reshaped the lunar orbit through resonant episodes. The Hakatai Shale now extends this empirical reach into the Mesoproterozoic with a record whose internal consistency—matching precession, eccentricity, and obliquity signals across two geographically separated sections—strengthens confidence that the rhythms are genuinely astronomical in origin rather than products of local tectonic or depositional noise.

The practical implications extend well beyond deep-time astronomy. Accurate knowledge of past astronomical frequencies underpins astrochronology, the dating method that uses orbital cycles to refine the geological time scale, and the new results constrain how those frequencies differed in the Precambrian, when shorter days and a closer Moon altered the pacing of climate cycles. The team’s cyclostratigraphic data and analyses have been made openly available through Zenodo, and the ZB23 astronomical solutions are publicly accessible, allowing other researchers to test and extend the reconstruction. As more ancient rhythmically deposited successions are examined with these tools, sedimentary rocks may continue to serve as long-term observatories of the heavens—recording, in ordinary mud, the slow gravitational conversation between Earth, the Moon, and the wandering planets.

Subject of Research: Reconstruction of Mesoproterozoic Earth–Moon dynamics and Solar System orbital evolution from Milanković cycles in Grand Canyon sedimentary strata

Article Title: Earth–Moon and Solar System history recorded in Mesoproterozoic Grand Canyon strata

Article References: Lantink, M. L., Eyster, A., Kocken, I. J., Meyers, S. R., & Zeebe, R. E. (2026). Earth–Moon and Solar System history recorded in Mesoproterozoic Grand Canyon strata. Nature Geoscience. https://doi.org/10.1038/s41561-026-02100-3

Image Credits: AI Generated

DOI: 10.1038/s41561-026-02100-3

Keywords: Milanković cycles, Hakatai Shale, Grand Canyon, Earth–Moon system, Mesoproterozoic, cyclostratigraphy, solar system dynamics, obliquity, lunar distance, astrochronology, secular resonance, tidal evolution