The tectonic regimes of the Earth and other terrestrial bodies (e. g., terrestrial planets, rocky moons and asteroids) dominates their rate of surface cooling, internal and compositional evolution. The sporadic geological records of the Earth show clues of the presence of very active "pre-plate tectonics" before the onset of plate tectonics, which resulted in rapid early crust-mantle differentiation. However, our understanding of the pre-plate tectonics confines to the conventional models, such as stagnant-lid regime, due to scarcity of geological records and incomplete means of researches when it comes to this "dark age" of the Earth. From a view of comparative planetology, however, results of over 40 years' space explorations challenge our understanding of how terrestrial bodies evolves, e. g., by discoveries of large-scale volcanism, high surface heat flow and resurfacing rate on Jupiter's moon Io. These exotic observations requires a new tectonic model, heat-pipe tectonics, to provide better explanations. The heat-pipe tectonics features rapid, vertical migration of energy and materials between the interior and the surface of a terrestrial body via large-scale volcanism, specifically through swift advection and phase changes of materials during generation, ascent and eruption of the mantle-derived magma/melts, as well as their subsequent return to the deep mantle after cooling, stacking and subsidence at the surface. As a result, the volcanism dominated heat-pipe tectonics is capable of achieving much higher efficiency of heat transfer between the interior and the surface of Io than the conduction-dominating stagnant-lid tectonics or the plate tectonics cooling Earth's interior via formation and subduction of plates. Despite the significant differences in term of internal heating mechanism between the early Earth and Io, they share much in common in the activeness of volcanic activities, intense internal heating and high internal temperature. Therefore, Io is of great reference value for understanding the pre-plate tectonic dynamics of the early Earth. In this paper, we reviewed the key discoveries of Io in the past 40 years, as well as the birth of the concept of heat-pipe tectonics on the basis of these observations. The possibility of heat-pipe tectonics on the early Earth was discussed. The distinctive vertical recycle of crust-mantle materials during operation of the heat-pipe tectonics tends to impede the formation and accumulation of the mantle-derived felsic components. Therefore, the upper limit age of large scale occurrence of TTG confines the possible heat-pipe tectonics to the Hadean-Eoarchean Earth (before similar to 3. 8Gyr ago) and was replaced by other tectonic regimes in response to the decrease of its internal heating rate. To some extent, our further understanding of Earth's possible heat-pipe tectonics depends on the knowledge of the Io's on-going heat-pipe tectonics that is more liable to be acquired, due primarily to the scarcity of geological observations of early Earth itself.
| ACTA PETROLOGICA SINICA Volume: 36 Issue: 12 Pages: 3853-3870 DOI: 10.18654/1000-0569/2020.12.17 Published: 2020 |
| Zhang QingWen; Liu Yun |
Chinese Acad Sci, Inst Geochem, State Key Lab Ore Deposit Geochem, Guiyang 550081, Peoples R China.
View here for the details