The Rocks of Oregon
Igneous rock is one type of rock that is formed when magma hardens and cools deep underground or when lava hardens and cools above ground, such as in the event of an eruption. Volcanic eruptions in the Cascade Mountains formed tons of igneous rock such as basalt, granite and obsidian. Obsidian was used to make Stone Age tools and in modern times it is sometimes used to make jewelry.
Metamorphic rocks are the rarest of the three rock types. Metamorphic rocks all start out as either sedimentary or igneous rocks and are changed and compacted over millions of years by the pressure and heat that are present deep within the earth. Metamorphic rocks are always denser than their original form and are also more resistant to erosion. Marble is a well-known metamorphic rock and is actually limestone that has been compressed and heated over millions of years. The Wallowa Mountains contain large quantities of metamorphic rock.
Sedimentary rocks are the third type of rock and are formed at the earth’s surface. Sedimentary rocks are composed of pieces of rock, fossils and minerals that have been eroded over time. These bits and pieces or “sediments” are washed downriver and fall to the bottom of bodies of water. Over hundreds of thousands of years, new layers of sediment continue piling up and apply pressure to the sediment layers below, which eventually results in the formation of sedimentary rocks such as limestone. One place in Oregon where sedimentary rocks are abundant is the Oregon Caves National Monument.
Meisel Rock Products is an Oregon rock supply company that owns a number of quarries in different areas of the state. We produce a wide variety of rock, sand and gravel products for residential and commercial needs. Whether it’s a backyard retaining wall or a new highway being built, Meisel Rock Products can provide the right materials to get the job done.