This is the most disseminated type of terrestrial impact crater. The height of the uplift is about half of the crater's depth. The deep trough is filled with impact melt rocks, brecciated and metamorphosed rocks of the crater basement. In the Boltysh crater in Ukraine the annular trough is filled with an impact melt sheet 11 km in diameter and up to 240 m thick. This sheet was formed by cooling of the lake of high temperature silicate melt that surrounded the central uplift immediately after the crater formation.
Many complex craters are widespread in America, Europe, Asia, etc.
The space images of the complex Spider crater in Australia reminds one of a spider's figure by the radial system of ridges spread from the center of the uplift. But the central uplift is not visible in many complex craters that are filled with sediments. The terrestrial craters with a central uplift form a transition to the ring and multi-ring impact structures as their diameters increase to some tens of kilometers. The West Clearwater crater in Canada is a classic example of a ring impact structure. The annular uplift of the basement rock forms a ring of islands in the crater lake.