Related Experiment Videos
Late Proterozoic and Paleozoic Tides, Retreat of the Moon, and Rotation of the Earth
1C. P. Sonett, Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. E. P. Kvale, Indiana Geological Survey, Indiana University, Bloomington, IN 47405, USA. A. Zakharian, Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. M. A. Chan, Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112, USA. T. M. Demko, Department of Earth Resources, Colorado State University, Fort Collins, CO 80523, USA.
Abstract:
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 dxi/dt approximately k2 sin(2delta) (where xi is the Earth-moon radius vector, k2 is the tidal Love number, and delta 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 approximately18 hours.