Rock Types: Igneous, Sedimentary, and Metamorphic Rocks Explained. Posted: March 12, 2025 | Last updated: March 12, 2025. This 1930s educational film explores the natural landscapes, geological ...

Metamorphic rock is the result of the transformation of a pre-existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat ...

Understanding geology is critical to studying paleontology because fossils are preserved in rock. The characteristics of the rocks that hold fossils can be as informative as the fossils themselves.

In a recent study, geologists say Michigan is home to the oldest known rock in the nation. Watersmeet gneiss is found in Michigan's Upper Peninsula. Minnesota's Morton gneiss previously held the ...

While the formation of sedimentary rock is perfect for the preservation of fossils, the formation of igneous and metamorphic rock isn’t so suited, resulting in the removal of the traces of ancient ...

An analysis of minerals in the Watersmeet Gneiss (shown) suggest the metamorphic rock dates to about 3.6 billion years ago, potentially making it the oldest known rock in the United States.