Presentation on theme: "Some Basic Geology Classes of Rocks. Igneous Formed by solidification of gaseous or molten material from cooling magma or lava More commonly seen in areas."— Presentation transcript:
Some Basic Geology Classes of Rocks
Igneous Formed by solidification of gaseous or molten material from cooling magma or lava More commonly seen in areas such as the Canadian Shield where bedrock from the Precambrian lies at the surface. Examples: basalt, obsidian, granite (cools more slowly), volcanic ash (tuffa, pumice)
Basalt Columns Giant's Causeway - Ireland
Devil’s Tower, WY
Basalt Columns Keweenaw Peninsula Michigan
Basalt with Opal
Volcanic Ash (Tuff)
Volcanic Ash (Pumice)
Sedimentary Formed by compaction of material Clastic rocks: older rock broken up by ice, wind, water (erosion) Shale, sandstone, clay Organically/chemically produced rocks Limestone, chalk, coal – from living organisms Salt - chemical Gypsum - chemical
Starfish in Illinois limestone
Layers of sediment formed on a sloping portion of the Silurian reef.
Devonian Dolomite Silurian Limestone: which is older?
Dolomite from Joliet Dolomite cliff
Saint Peter Sandstone along Rock River
French Canyon at Starved Rock State Park. Also St. Peter sandstone.
Pictured Rocks National Lakeshore, Michigan Lake Superior
Puddingstone Type of sedimentary rock Michigan Puddingstone is a conglomerate of primarily quartzite and pebbles of jasper
Metamorphic Form when igneous or sedimentary rocks are changed by heat, pressure, or infiltration with other materials Characteristics flaky: slate (comes from mud) non-flaky: marble (comes from limestone) sparkly: gneiss (comes from igneous or sedimentary rocks) Quartzite: comes from sandstone