Some recent work has cast an interesting shadow on the whole framework of plate tectonics in time. The authors of a paper in Nature in 2001 concerned with the dating of zircons by lead-uranium isotope methods obtained dates of 600 million and 1.6 billion years from a suite of samples from cores alongside the mid-atlantic ridge, in lavas that were expected to give very recent dates according to the plate tectonic theory. Just what the ultimate explanation for these anomalies will be is not clear, but in the present context it probably has more to do with the validity of radiometric dating methods than it does with plate tectonics.
I have cast a model for earth history on the concept of plate tectonics. This document, although tentative, is available at this address .