Hong Kong's geology is primarily composed of granite, which forms the backbone of the region's landscape. This granite was formed during the Mesozoic era, around 200 million years ago, and is characterized by its coarse texture and light color. The area also features sedimentary rocks, such as sandstone and shale, which were deposited in ancient river and marine environments. In addition to granite and sedimentary rocks, Hong Kong has a complex geological structure influenced by tectonic activity. The region is situated near the boundary of the Eurasian Plate and the Philippine Sea Plate, leading to the formation of various landforms, including hills and valleys. This tectonic setting contributes to the area's rich biodiversity and unique ecosystems.