Earth's oldest near-surface material, the cratonic crust, is typically underlain by thick lithosphere (>200 km) of Archean age. This cratonic lithosphere likely thickened in a high-compressional-stress environment, potentially linked to the onset of crustal shortening in the Neoarchean. Mantle convection in the hotter Archean Earth would have imparted relatively low stresses on the lithosphere, whether or not plate tectonics was operating, so a high stress signal from the early Earth is paradoxical. We propose that a rapid transition from heat pipe–mode convection to the onset of plate tectonics generated the high stresses required to thicken the cratonic lithosphere. Numerical calculations are used to demonstrate that an existing buoyant and strong layer, representing depleted continental lithosphere, can thicken and stabilize during a lid-breaking event. The peak compressional stress experienced by the lithosphere is 3×–4× higher than for the stagnant-lid or mobile-lid regimes immediately before and after. It is plausible that the cratonic lithosphere has not been subjected to this high stress state since, explaining its long-term stability. The lid-breaking thickening event reproduces features observed in typical Neoarchean cratons, such as lithospheric seismological reflectors and the formation of thrust faults. Paleoarchean "pre-tectonic" structures can also survive the lid-breaking event, acting as strong rafts that are assembled during the compressive event. Together, the results indicate that the signature of a catastrophic switch from a stagnant-lid Earth to the initiation of plate tectonics has been captured and preserved in the characteristics of cratonic crust and lithosphere.
Article navigation
Article Contents
JOURNAL ARTICLE
Formation of cratonic lithosphere during the initiation of plate tectonics
A.P. Beall
A.P. Beall
1
School of Earth Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
Search for other works by this author on:
L. Moresi
L. Moresi
1
School of Earth Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
Search for other works by this author on:
C.M. Cooper
C.M. Cooper
2
School of the Environment, Washington State University, PO Box 642812, Pullman, Washington 99164-2812, USA
Search for other works by this author on:
Geology (2018)
Published:
April 06, 2018
Article history
-
Views Icon
Views
-
CiteCitation
A.P. Beall, L. Moresi, C.M. Cooper; Formation of cratonic lithosphere during the initiation of plate tectonics. Geology doi: https://doi.org/10.1130/G39943.1
Download citation file:
× -
Share Icon
Share
-
Tools Icon
Tools
Search
Search
Sign in
Don't already have an account? Register
You could not be signed in. Please check your email address / username and password and try again.