Tripole on seafloor and tripole on Earth surface: Dynamic connections

The three extreme regions of the Earth’s surface environment, i.e. the Antarctica, Arctic and Qinghai-Tibet Plateau, are known as the " three poles (tripole)” of the surface Earth system. In this paper, the concept of tripole of deep-Earth geodynamic system is proposed, which includes Tuzo, Jason and the Circum-East Asian subduction system. Since the principle parts of the deep-Earth tripole are developed mainly in the deep mantle beneath the seafloor, they are called hereby the seafloor tripole. The surface tripole and the deep tripole collectively consists of the " six poles” of the geosphere, which are the unavoidable research objects in the frontiers of geosciences, such as global change, deep-time Earth, deep-Earth geodynamics, Earth system and habitable Earth. They are the six links and breakthroughs in the multi-spherical interaction of the Earth as well as the key to search for the dynamic mechanism of the Earth system. Tuzo and Jason are Large Low Shear-wave Velocity Provinces (LLSVPs) located under the Atlantic and the Pacific, respectively. They control the formation and evolution of large igneous provinces and micro-plates, as well as centralized volcanic degassing which leads to the changes in atmospheric circulation. They also continuously cause the formation of micro-plates, push them moving northward, and constantly assemble them into the Circum-East Asian subduction system. A large amount of substances are subducted deeply to trigger the deep material circulation. Simultaneously, a large amount of greenhouse gases are released through island arcs, which changes the atmospheric circulation of the surface Earth system. Plate assembly and dispersion together will change the continent-ocean configuration patterns in addition to the global seaways, the uplift and collapse of the plateaus, and further regulate the operation of surface Earth fluid system, including both the ocean circulation and atmospheric circulation. The formation and evolution of ice sheets are also controlled by them. The " three poles” under the seafloor are indeed the fundamental controlling factors of the supercontinent convergence and dispersal in the geological history. The multi-scale periodic changes of the surface Earth system are mainly controlled by the eccentricity of the Earth around the Sun, the obliquity of the Earth axis and the precession. Climate change is driven by both tropical and ice-sheet driving forces. In a word, although the Earth is habitable after the Early Earth, the interaction between the geosphere and biosphere is extremely complex. The study of the geospheric " six poles” is doubtlessly the breakthrough and growth point for the study of habitable Earth.