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The Rock Cycle in Michigan Prepared by the Michigan Department of Environmental Quality Office of Geological Survey What is the Rock Cycle ? Rock Cycle explains how Rocks and Natural Processes are related The weathering Sedimentary pr e ing ss ur e lt me ,h ea t Metamorphic Igneous A more traditional definition is: Ro c k C y c l e is a sequence of events involving the formation, alteration, destruction, and reformation of rocks as a result of natural processes Glossary of Geology, Bates & Jackson, AGI We will use the graphic seen in the background to help represent the Rock Cycle There are many ways to show the various relationships between the rocks and the related natural processes Before we look at the Rock Cycle in detail, let’s review some basic information … The Rock Cycle involves the recognition of three main classes of rocks All three types are found in Michigan The three rock types are … Sedimentary CEMETERY Rocks Metamorphic METABOLIC Rocks Igneous INGENIOUS Rocks Right? The eminent 18th century lawyer, doctor, gentleman farmer and founder of modern geoscience, James Hutton, developed the concept of the Rock Cycle to show how rocks and natural, physical processes are interrelated The understanding of the world in the 18th century was different from today … Middle Devonian Rocks in Michigan Middle Devonian rocks are made up of many different sedimentary rock formations These rocks are shown in blue The Rock Cycle Metamorphic Sedimentary lt me ing Igneous Igneous Rocks form from molten rock or magma in the subsurface or from lava extruded at the surface Becoming an IGNEOUS ROCK … Any existing rock – igneous, metamorphic or sedimentary - can be subjected to enough heat and or pressure causing it to melt Molten rock is called magma When magma cools to a solid it becomes an igneous rock The kind of igneous rock formed depends on what was melted and how it cooled Igneous rocks are classified based on their mineral composition and texture In Michigan, igneous rocks make up the bedrock in the western northern peninsula Igneous and Metamorphic rocks Sedimentary rocks Generalized Bedrock Geology of Michigan Igneous rocks found in Michigan include: granite basalt granodiorite rhyolite pegmatite The Rock Cycle Metamorphic pr e ss ur e ,h ea t Sedimentary Igneous Pressure, heat and fluids cause preexisting rocks or sediments to become metamorphic rocks Becoming a METAMORPHIC ROCK … If the igneous rock basalt is exposed to sufficient heat and or pressure it can be transformed into the metamorphic rock call metabasalt When the prefix meta is applied to a rock name that means that the original rock has been metamorphosed Becoming a METAMORPHIC ROCK … If the sedimentary rock limestone or dolomite is metamorphosed it can become the metamorphic rock marble If the sedimentary rock sandstone is metamorphosed it can become the metamorphic rock quartzite If the sedimentary rock shale is metamorphosed it can become the metamorphic rock slate Becoming a METAMORPHIC ROCK … If the metamorphic rock slate is metamorphosed it can become the metamorphic rock phyllite If the metamorphic rock phyllite is metamorphosed it can become the metamorphic rock schist If the metamorphic rock schist is metamorphosed it can become the metamorphic rock gneiss In Michigan, metamorphic rocks make up the bedrock in the western northern peninsula Igneous and Metamorphic rocks Sedimentary rocks Generalized Bedrock Geology of Michigan DEQ GSD - The Rock Cycle in Michigan - February 2001 Metamorphic rocks found in Michigan include: iron ore, schist, slate, quartzite, marble, and gneiss Igneous and Metamorphic rocks Sedimentary rocks Generalized Bedrock Geology of Michigan DEQ GSD - The Rock Cycle in Michigan - February 2001 Michigan's State Gemstone is chlorastrolite a variety of pumpellyite Also called greenstone and ‘Isle Royal Greenstone’ It is a metamorphic mineral found in altered igneous rocks (basalts, and diabases) DEQ GSD - The Rock Cycle in Michigan - February 2001 The Rock Cycle weathering Metamorphic pr e ss ing ur e lt me ,h ea t Sedimentary Igneous The Rock Cycle does not go in just one direction Any given rock can go through any part of the cycle any number of times DEQ GSD - The Rock Cycle in Michigan - February 2001 The Rock Cycle weathering Metamorphic pr e ss ing ur e lt me ,h ea t Sedimentary I hope you better understand the Rock Cycle and what it means Igneous Please email any comments about this program to Steve Wilson: wilsonse@Michigan.gov - thanks DEQ GSD - The Rock Cycle in Michigan - February 2001 [...]... Metamorphic rocks Sedimentary rocks Generalized Bedrock Geology of Michigan In Michigan, sedimentary rocks make up the bedrock in the eastern northern, and southern peninsulas Sedimentary rocks found in Michigan include: Igneous and Metamorphic rocks Sedimentary rocks Generalized Bedrock Geology of Michigan sandstone, shale, limestone, rock salt, and rock gypsum As the ice advances it can scour the bedrock... zonochlorite There are over 300 minerals found in Michigan Each mineral has its own set of uniquely identifiable properties or characteristics Minerals combine to form Rocks Some Rocks are made up of just one mineral like the sedimentary rock salt (made up of the mineral halite) that is mined near Detroit Others Rocks are made up of many granite gneiss, minerals - like the igneous rock and the metamorphic rock. .. and gravity at the surface He did not know about radioactive heating from inside the earth Solar energy, gravity and radioactive heating are the major forces driving the Rock Cycle As a result, the Rock Cycle will be self-sustaining for thousands of millions of years How does an antique concept like the Rock Cycle hold up in light of contemporary data and scientific thinking? Of special interest is Plate... Marquette Now that some of the basics have been covered, lets consider some of the details about the Ro c k C y c l e The Rock Cycle weathering Sedimentary Igneous Metamorphic Rocks are weathered, eroded, transported, deposited,and lithified to form sedimentary rocks Becoming a SEDIMENTARY ROCK … The igneous rock granite can be physically weathered to produce clay and sand These sediments can be transported... make up elements elements of Geology Elements combine to form the natural compounds Natural compounds and elements combine to form minerals Minerals make up rocks What are Minerals? Rocks make up the Earth How can we tell what they are? The identifiable characteristics of Minerals are naturally occurring inorganic elements or compounds having an orderly internal structure and a characteristic chemical... Sedimentary rocks can be physically weathered to produce sediments that can become other sedimentary rocks Becoming a SEDIMENTARY ROCK … H2O + CO2 H2CO3 Chemical weathering dissolves the minerals in rocks The resulting dissolved compounds could form evaporites like rock salt or rock gypsum or chemical precipitates like some kinds of limestones What forms depends upon composition and depositional environment... 3,700°C Inner Core 5,150 to 6,370 km 4,300°C Now that we better understand the largest components of Geology … lets move to some of the smallest components of Geology … There is a hierarchy to the Atoms make up elements elements of Geology Elements combine to form the natural compounds Natural compounds and elements combine to form minerals Minerals make up rocks Rocks make up the Earth Atomic Theory... Of special interest is Plate Tectonics The mantle, crust and surface of the earth can be thought of as a giant recycling machine; rocks are neither created nor destroyed, but redistributed and transformed from one rock type to another S M I If you were to ask a geologist what the earth is … What do you think the response would be? Diagram of the Interior of the Earth Crust 0 to 40 km 0°C Upper Mantle... form sedimentary rocks Clay can become shale Sand can become sandstone Becoming a SEDIMENTARY ROCK … The metamorphic rock gneiss can be physically weathered to produce clay and sand These sediments can be transported deposited and lithified to form sedimentary rocks Clay can become shale Sand can become sandstone Becoming a SEDIMENTARY ROCK … Sedimentary rocks can be physically weathered to produce... matter is composed of the atoms of about 100 different chemical elements It further proposes that chemical compounds are formed by the combination of the atoms of different chemical elements Elements can be arranged, based on their identifiable properties, into the Periodic Table O Na Mg K Ca Only Al Si Fe eight elements make up over 98% of the earth’s crust! There is a hierarchy to the Atoms make up elements