TS Must-Read – Dietz (1961) Continent and ocean basin evolution by spreading of the sea floor

Dietz 1961 “Continent and Ocean Basin Evolution by Spreading of the Sea Floor” paper was ground-breaking for plate tectonics. Almost literally, as it discussed the sea-floor spreading theory. Certainly away from the consensus at the time, this article is a classic in divergent tectonic settings and it may be an interesting piece of work for ECS working in tectonics and, more particularly, in continental rifting. Well worth exploring!

The article introduces a new theory, which is referred to as Spreading Sea Floor Theory, to explain the evolution of continents and the opening of oceanic basins, by means of a crustal evolution model derived by intuition from the interpretation of seafloor bathymetry. The paper summarises the model’s assumptions through an overview and discussion of the basic concepts explored, such as large-scale mantle convection cells, the distinctive composition, physical properties, and relative strength of the asthenosphere, and continental and oceanic crust, as well as the concepts of sial and sima. Then, the contribution addresses in detail the seafloor spreading theory. The paper elegantly ends with a discussion of major implications, including continental drift, the age of oceanic crust, seafloor magnetic anomalies, and fracture zones.

Animation of Seafloor spreading (image credit: http://platetectonicstask.weebly.com/about.html).

David Fernández-Blanco, Gianluca Frasca, and Pan Luo took part in the discussion in the 3 weeks prior to this post. It is interesting to remark the observation pointed out by Pan about the relevance of this contribution in setting up most of the concepts that lay the foundations of plate tectonics theory. David commented on the elegance and brightness of the paper in reviewing classical concepts to set up a new theory. In this sense, Gianluca outlines how the paper enables us to follow the progressive discovery path behind the ideas of such evolution for continents.

The ideas detailed in the paper were extensively explored and debated during the ‘60s and the ‘70s, as such there are plenty of papers to discuss, two of which are now up on the subreddit (e.g., Wilson, 1965, 1966). These ideas have also been the basis of new concepts and major discussions over the past years. New frontiers are now open for the exploration of the tectonics on rocky planets, and comprehension of mantle convection is key to that. If this has caught your attention and you would like to further explore mantle convection, check the “CIDER summer school” tutorial video.

Written by Patricia Cadenas, Silvia Crosetto, Pan Luo and TS Must-Read Team

References

Wilson, T. J. (1965). A New Class of Faults and their Bearing on Continental Drift. Nature, 207, 343-347
Wison, T. J. (1966). Did the Atlantic Close and then Re-Open?, Nature, 211, 676-681