image: NSF- and ICDP- funded Colorado Plateau Coring Project CPCP-1 drilling site at Chinde Point, Petrified Forest National Park, AZ, at dusk. view more
Credit: Paul E. Olsen
Researchers report a system for obtaining information about planetary motions approximately 200 million years ago. Solutions of models for planetary motions are valid only within the past 60 million years, due to the chaotic nature of the Solar System. Geological records of climate variations modulated by orbital variations, which are older than 60 million years, could help to extend such solutions farther back in time. To do so, Paul Olsen and colleagues used highly resolved data from two scientific coring experiments in lake sediments from the Late Triassic and Early Jurassic epochs, approximately 220-199 million years ago. Using the data sets as a Geological Orrery--named after 18th-century mechanical planetaria--the authors recovered precise and accurate values for the precession frequencies of the perihelions of Mercury, Venus, Earth, Mars, and Jupiter. Certain combinations of these frequencies give rise to periodic oscillations in Earth's motion that produce corresponding variations in climate. The Geological Orrery could be extended by the addition of paired low-latitude and high-latitude records spanning the early Paleogene to Permian periods, 50-299 million years ago, allowing empirical mapping of orbital frequencies over this period. According to the authors, such mapping could constrain models of Solar System evolution and provide further tests of gravitational models.
Article #18-13901: "Mapping Solar System chaos with the Geological Orrery," by Paul E. Olsen et al.
MEDIA CONTACT: Paul E. Olsen, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY; tel: 845-365-8491, 845-729-2434; e-mail: polsen@ldeo.columbia.edu
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Journal
Proceedings of the National Academy of Sciences