Linda A. Hinnov
Professor of Geology
Department of Atmospheric, Oceanic and Earth Sciences
George Mason University

Twentieth century lunar laser ranging and historical eclipse observations provide direct evidence of lunar recession and change in length-of-day for the past 2500 years. For earlier times, a handful of uncoordinated paleontological (corals, bivalves) and sedimentary ("tidalite") data offer quantitative snapshots of days per year back to 2.5 Ga. A third archive not yet assessed is cyclostratigraphy: faster rotation rates in deep time should translate into faster precession. A paleorotation database is needed to consolidate (and reanalyze) legacy data. New entries to this database will entail assessment of obliquity and precession frequencies from cyclostratigraphy. Finally, the analysis of a potential tidalite from the >3.7 Ga Isua Formation may provide the oldest quantitative data pertaining to Earth-Moon dynamics.

Current paleorotation projects:

A Paleorotation Database
Paleozoic Milankovitch Cycles
Precambrian Milankovitch Cycles