Crust (geology) magma ocean and floated to the top; however, it is unlikely that Earth followed a similar pattern, as the Moon was a water-less system and Earth had water. The Martian meteorite ALH84001 might represent primary crust of Mars; however, again, this is debated. Like Earth, Venus lacks primary crust, as the entire planet has been repeatedly resurfaced and modified. Secondary crust is formed by partial melting of silicate materials in the mantle, and so is usually basaltic in composition. This is the most common type of crust in the Solar System. Most of the surfaces of Mercury, Venus, Earth, and
The Conflict Over the Sovereignty of the Diaoyu Islands -- between Taiwan (ROC), China (PRC), & Japan depth of the Okinawa trough that locates in the east is as deep as 2,717 meters, forming a natural sea boundary with China and the Ryukyu islands. As the geological structure of the Ryukyu Islands belong to "oceanic crust", the Diaoyu Islands are "continental crust" that makes a significant difference in between those two. Also, the Diaoyu Islands has one of the largest scale of continental reef layer that contains an abundant amount of river deposits such as the Yangtze River and the Yellow River, and is therefore potentially rich in oil. The Diaoyu islands are considerably much more strategic