Any small lithospheric plate. To be classed as a microplate, any present-day, small fragment of lithosphere should have identifiable plate margins, though adherence to this requirement is not strict (see also terrane). Microplates with continental crust are also ‘microcontinents’, though the reverse is not necessarily true: Japan is a microcontinent but a part of the Eurasian Plate, and the Rockall microcontinent has long ceased its independent movement. Microplates, especially those that have continental crust, are considered by many geologists to be important in the formation of several orogenic belts, e.g. the Cordillera of western N. America. Most authors suggest that the break-up of Gondwana produced many microplates whose subsequent collision with and accretion to Eurasia may explain the complexities of the Alpine– Himalayan belt, with the strain being taken up partly by the slipping, rotation, and slicing up of microplates and partly by deformation of other terranes.