Late Proterozoic and Paleozoic Tides, Retreat of the Moon, and Rotation of the Earth

• Published in: Science (American Association for the Advancement of Science) Vol. 273; no. 5271; pp. 100 - 104
• Main Authors: Sonett, C. P., Kvale, E. P., Zakharian, A., Chan, Marjorie A., Demko, T. M.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 05.07.1996; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Angular momentum; Astronomical rotation; Earth; Earth rotation; Earth sciences; Earth, ocean, space; Earths Moon; Exact sciences and technology; Geology; History; Internal geophysics; Lunar orbits; Lunar tides; Marine; Moon; Orbits; Petrology of sedimentary rocks except quaternary rocks; Rotation; Sedimentary rocks; Semimajor axis; Solar orbits; Solid-earth geophysics, tectonophysics, gravimetry; Sun; Tides; Indiana; United States; Australasia; Australia; Alabama; North America; Utah; South Australia; USA, Utah; USA, Indiana; USA, Alabama; rhythmite; length of day; Moon; rotation; Pennsylvanian; Precambrian; friction; tides; Paleozoic; sedimentary rocks; laminites; periodicity; Proterozoic; clastic rocks
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.273.5271.100

The tidal rhythmites in the Proterozoic Big Cottonwood Formation (Utah, United States), the Neoproterozoic Elatina Formation of the Flinders Range (southern Australia), and the Lower Pennsylvanian Pottsville Formation (Alabama, United States) and Mansfield Formation (Indiana, United States) indicate that the rate of retreat of the lunar orbit is dξ/dt ∼ k$_2$ sin(2δ) (where ξ is the Earth-moon radius vector, k$_2$ is the tidal Love number, and δ is the tidal lag angle) and that this rate has been approximately constant since the late Precambrian. When the contribution to tidal friction from the sun is taken into account, these data imply that the length of the terrestrial day 900 million years ago was ∼ 18 hours.