Abstract: Any plate has a growth process from small to large. Microblocks or microplates are sometimes the precursors of large plates. The origin, growth, aborting, extinction and residual processes of microblocks are of great significance for the study of plate tectonics. Microblock can be classified as micro-continental, micro-oceanic and micro-mantle block according to its composition. In this paper, the characteristics of microblocks in the Pacific, Indian and Atlantic oceans are summarized according to five environments of the mid-ocean ridge, subduction system, deep-sea intraplate, extensional rifting and collisional orogenic systems. We first propose a genetic classification of micro-blocks as the detachment-, rifting-, transform-, propagation-, ridge jumping-, subduction-, accretion-, collision- and delamination-induced micro-mantle blocks. We then discuss the different types of micro-block boundaries systematically. These micro-block boundaries include active or inactive detachment fault, subduction zone, mid-ocean ridge, transform fault, fracture zone, lithosphere-scale fault, pseudo-fault, intra-oceanic collisional zone, overlapping spreading center, non-transform offset, ridge offset and others. The key research of boundary formation is the stability analysis of triple junctions. These microblocks, within the oceanic basin or along the oceanic margin, are significant not only for developing deep ocean fine structural analysis and plate reconstruction, but also for explaining the causes of microblocks in orogens, intra-continent, intra-ocean, intra-mantle and continental margins to improve research precision towards a more detailed understanding of orogenic belt evolution, intraplate deformation and mantle processes, or even extending our study into the early Precambrian pre-plate tectonic mechanisms.

Key words:  micro-block, microplate, intraplate, continental margin, mid-ocean ridge, subduction zone, Precambrian