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This Article Appeared in a Journal Published by Elsevier. the Attached This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier’s archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy Tectonophysics 589 (2013) 44–56 Contents lists available at SciVerse ScienceDirect Tectonophysics journal homepage: www.elsevier.com/locate/tecto A planetary perspective on Earth evolution: Lid Tectonics before Plate Tectonics John D.A. Piper ⁎ Geomagnetism Laboratory, Geology and Geophysics, School of Environmental Sciences, University of Liverpool, Liverpool L69 7ZE, UK article info abstract Article history: Plate Tectonics requires a specific range of thermal, fluid and compositional conditions before it will operate Received 27 September 2012 to mobilise planetary lithospheres. The response to interior heat dispersion ranges from mobile lids in con- Received in revised form 30 November 2012 stant motion able to generate zones of subduction and spreading (Plate Tectonics), through styles of Lid Accepted 25 December 2012 Tectonics expressed by stagnant lids punctured by volcanism, to lids alternating between static and mobile. Available online 12 January 2013 The palaeomagnetic record through Earth history provides a test for tectonic style because a mobile Earth of multiple continents is recorded by diverse apparent polar wander paths, whilst Lid Tectonics is recorded by Keywords: fi Planetary tectonics conformity to a single position. The former is dif cult to isolate without extreme selection whereas the latter Lid Tectonics is a demanding requirement and easily recognised. In the event, the Precambrian palaeomagnetic database Plate Tectonics closely conforms to this latter property over very long periods of time (~2.7–2.2 Ga, 1.5–1.3 Ga and 0.75– Palaeomagnetism 0.6 Ga); intervening intervals are characterised by focussed loops compatible with episodes of true polar Precambrian wander stimulated by disturbances to the planetary figure. Because of this singular property, the Palaeopangaea Precambrian palaeomagnetic record is highly effective in showing that a dominant Lid Tectonics operated throughout most of Earth history. A continental lid comprising at least 60% of the present continental area and volume had achieved quasi-integrity by 2.7 Ga. Reconfiguration of mantle and continental lid at ~2.2 Ga correlates with isotopic signatures and the Great Oxygenation Event and is the closest analogy in Earth history to the resurfacing of Venus. Change from Lid Tectonics to Plate Tectonics is transitional and the geological record identifies incipient development of Plate Tectonics on an orogenic scale especially after 1.1 Ga, but only following break-up of the continental lid (Palaeopangaea) in Ediacaran times beginning at ~0.6 Ga has it become comprehensive in the style evident during the Phanerozoic Eon (b0.54 Ga). © 2013 Elsevier B.V. All rights reserved. 1. Introduction however, we have a laboratory of preserved crust dating back to within ~0.7 Ga of the planetary origin which provides the opportunity to Ever since the recognition and definition of Plate Tectonics in the monitor the way that the lithosphere has grown and moved. The tem- 1960's, there has been ongoing debate about the temporal duration poral test of the dynamic history comes from palaeomagnetism, the of this process through the planetary history (e.g. Condie and preserved record of the fossil magnetism in rocks and the probability Kröner, 2008; Condie and Pease, 2008; Davies, 1992; Engel et al., that this magnetism is trapped by the lines of force from a simple source 1974; Piper, 1982, 1987; Stern, 2008). Has this tectonic style constrained to the planetary rotation, the Geocentric Axial Dipole prevailed throughout the ~3.9 Ga recorded evolution of the continen- (GAD) model. In this paper I show how limiting evidence from this tal crust or did Earth experience long intervals of lid-style tectonics record of remanent magnetism provides a highly robust definition of punctured by volcanic activity as seen on Mars or episodic mantle tectonic style on Earth since mid-Archaean (~2.8 Ga) times and demon- overturn and resurfacing as seen on Venus (e.g. Frankel, 1996; strates that Lid Tectonics dominated the planetary lithosphere before Nimmo and McKenzie, 1998)? This debate has been stimulated in re- Plate Tectonics became the style characterising the last (Phanerozoic, cent years by the discovery of numerous planetary bodies or b0.54 Ga) Eon of geological time. “super-Earths” and the expectation that many more will be discov- ered in the future by missions such as NASA Kepler (kepler.nasa. 2. Plate Tectonics, Lid Tectonics and planetary resurfacing: gov). Whilst considerable effort has gone into the computer modelling general considerations of potential super-Earths to predict the likelihood of Plate Tectonics, the validity of the conclusions must ultimately depend on observational An important constraint to the current debate is the evidence for data. The universe presents an instantaneous time frame, although recycling of crustal material throughout the preserved continental re- often looking backwards in time over many light years. On Earth cord (Armstrong, 1981; Condie et al., 2009a; Hawkesworth et al., 2010; Taylor and McLennan, 1985); the recognition of zircons dating ⁎ Fax.: +44 151 7943464. from times preceding the oldest crust preserved at the surface is an E-mail address: [email protected]. indication that this recycling has been underway since primary 0040-1951/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.tecto.2012.12.042 Author's personal copy J.D.A. Piper / Tectonophysics 589 (2013) 44–56 45 differentiation of the planet (e.g. Van Kranendonk, 2011). However rapid (b100 Myr) resurfacing with the last event completed Earth has also experienced intervals of intense magmatic–tectonic ac- 300–600 Myr ago (Strom et al., 1994) and the planet appears to be tivity interspersed with intervals of prolonged quiescence and the currently heating up pending a future such event. It remains possible motivation for recycling remains largely speculative. Many investiga- that Plate Tectonics analogous to Earth operated during resurfacing tions have highlighted possible causes for periodicity in the recycling although Nimmo and McKenzie (1998) conclude that a combination process including catastrophic slab avalanching into the mantle, man- of high mantle viscosity, high fault strength and thick basaltic crust tle plume generation and supercontinent cycles (Condie, 1998; may prevent subduction from being sustained on Venus and hence Gurnis, 1988; Stein and Hoffman, 1994; Tackley et al., 1994) whilst preclude the key signatures of Plate Tectonics. other workers have suggested that surface processes may be entirely The transition from a quasi-static lid-style to subduction-driven shut down for prolonged periods (O'Neill et al., 2007; Silver and Behn, plate-style tectonics is difficult to predict theoretically because it is 2008). Although these and other authors have usually implied that controlled by a complex interplay of rheological, compositional and this means the shutdown of Plate Tectonics, it remains unclear thermal parameters, in particular the temperature at the core–mantle whether this was really the process operating. boundary, and it also depends critically on the amount of water For purposes of this discussion Plate and Lid Tectonics need to be present at the planetary surface. However, models have become pro- clarified. Our understanding of Plate Tectonics is defined by the way gressively more sophisticated in recent years (Moresi and Solomatov, Earth surface processes have operated during the Phanerozoic Eon 1995, 1998; Rolf and Tackley, 2011; Tackley, 2000; Trompet and (b0.54 Ga), and most specifically since preservation of the remaining Hansen, 1998; van Heck and Tackley, 2011) and have sought to deter- ocean crustal record beginning with break-up of the supercontinent mine the point at which predicted convective stresses exceed the Pangaea in Jurassic times (b0.19 Ga). Plate Tectonics is driven pri- yield stress of a lithospheric lid. In general they predict three convec- marily by buoyancy forces operating within the oceanic lithosphere tive modes comprising (i) a mobile lid in constant motion able to gen- between young elevated constructive margins incremented by the erate zones of subduction and spreading, (ii) a stagnant lid covering products of decompression melting and old, cold and dense margins the whole surface and (iii) an episodic lid where the regime keeps descending back into the mantle. The latter incorporate the process interchanging between static and mobile. of subduction which defines the destructive boundaries of the plates. The most comprehensive models all show that plate tectonics will Tectonic processes occurring within the continental crust are also fo- become more likely as the planetary size increases if the convection is cussed on the plate boundaries and a consequence
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