Igneous
Metamorphic
Sedimentary
IGNEOUS ROCKS: Igneous rocks are formed ultimately by melting of the Earth’s interior. Igneous rocks are of two general types:
1. Intrusive, granite for example. These are rocks that have been intruded from hot liquid magma into rocks above from deep within the Earth, but never reached the surface. However, because of erosion, many of these rocks are now uncovered and we can see them in the mountains, and in many places in the landscape.
2. Extrusive, volcanic rocks for example. These rocks form volcanoes of different types, and result from outpouring of magma onto the Earth’s surface when it is then called lava. There are many types of volcanoes, some are explosive like Mt. St Helens in nearby Washington Sate, others are very liquid and flow for miles over nearly flat land like the plateau basalt lava around Kelowna. Kelowna also has very ancient explosive type volcanoes such as Knox Mountain, Mount Boucherie, and Black Knight Mountain amongst others.
METAMORPHIC ROCKS: Metamorphic rocks are rocks formed from pre-existing rock by great pressure and temperature wherein the minerals in the rock are changed and re-formed giving the rock a banded appearance, the bands being composed of different minerals. The rocks are called schist or gneiss and could be granitic, or a great variety of other compositions. Most of the rock in Okanagan Mountain Park is composed of metamorphic rock. Marble is also a metamorphic rock changed from a rock known as limestone.
SEDIMENTARY ROCK: Sedimentary rock is material formed by erosion and deposition by a great variety of processes, and turned into rock by consolidation over long periods of geologic time and a result of deep burial. Thus a sand deposit becomes a sandstone; a gravel deposit becomes a conglomerate. A mud or clay deposit becomes a shale. Sedimentary deposits are also classified, according to their origin: Clastic, sandstone, for example, Chemical, limestone, for example, Organic, coal, for example, and so on.