The Structural Characteristics of Lithosphere in the Continent of Eurasia and Its Marginal Seas

Abstract

The continent of Eurasia and its surrounding marginal seas are assembled by more than thirty plates and blocks with different scales, characteristics, and different ages. These plates and blocks were formed through drifting, converging, separating, colliding, and accreting throughout much of Earth's history, finally resulting in the present assembled plate of Eurasia. The plates and blocks in Eurasia and its surrounding marginal seas can be divided into six types: (1) large Precambrian cratonic plates or shields; (2) small Precambrian cratonic plates or blocks; (3) Phanerozoic orogens; (4) continent-continent collisional orogens; (5) Neozoic marginal sea basins; (6) continental rift basins. High-resolution surface wave tomographic images indicate that the velocity characteristics of the lithosphere and asthenosphere are quite similar for the same type of plates or blocks. However, the velocity characteristics are different for different types of plates or blocks. The lateral changes in velocity for different plates or blocks decrease to the depth of 400 km and beyond. In general, Precambrian cratonic shields show high velocity, huge thickness and do not have an asthenosphere zone. On the other hand, marginal seas, rift systems and orogens show lower velocity and have thick asthenospheric zones. We collected all three-dimensional images and explosion seismic data of both crust and lithosphere in Eurasia, and constructed a model of the lithosphere in Eurasia and its surrounding marginal seas. We discuss the structure and the characteristics of lithosphere in detail.