Simatic describes the dense, dark-colored rocks that make up the lower part of the Earth's crust and oceanic plates. These materials are heavily composed of silica, magnesium, and iron-bearing minerals like olivine and pyroxene. In exploration, identifying a simatic layer indicates a transition into denser environments, which host different mineral deposits than lighter continental rocks.
Heard on the job
We're seeing mostly basalt and gabbro in these samples, confirming a transition into a simatic basement.
Insider tip
Derived from silicon (Si) and magnesium (Ma), the term is an older but still useful way to describe the composition of the oceanic crust.
Do not mix it up with
- Sialic: Simatic refers to denser, magnesium-rich oceanic crust, while sialic refers to lighter, aluminum-rich continental crust.