Creation of Shimane: Geological Composition Chart

The geological features of Shimane Prefecture can be divided into three main types.
The first type is found in the inland, midwestern part of the prefecture, with sedimentary rocks dating from the Paleozoic era to the Mesozoic era along with metamorphic rocks that were pressured by orogenic (mountain-building) activity. (Figure 1, Right)
The second type is found primarily in the eastern region, with igneous rocks dating from the Cretaceous period to the Paleogene period (marked in red). (Figure 2, Right)
The third type is found along the coastline, with volcanic rocks and sedimentary rocks dating from expansion of the Sea of Japan in the Neogene period of the Cenozoic era. (Figure 3, Right)

1. Strata and rocks from the Paleozoic era to the Jurassic period of the Mesozoic era
2. Strata and rocks from the Cretaceous period of the Mesozoic era to the Paleogene period of the Cenozoic era
3. Strata and rocks from the post-Neogene period of the Cenozoic era

From the Geological Map of Shimane Prefecture (New Edition)