SEDIMENTARY ROCKS-MINERAL OR ROCK FRAGMENTS OR MATERIAL OF ORGANIC ORIGIN ARE ERODED OR DISSOLVED AND THEN DEPOSITED IN LAYERS AT EARTH'S SURFACE CRUCIAL FACTORS: SOURCE ROCK FROM WHICH SEDIMENT DERIVED TRANSPORT MECHANISM (WIND, WATER, ICE) SITE OF DEPOSITION (RIVER, LAKE, OCEAN, DESERT) PLATE TECTONIC SETTING SEDIMENTS 5% OF EARTH'S CRUST, BUT MOST COMMON SURFACE ROCKS, RECORD EARTH HISTORY, & VALUABLE FOR RESOURCES (oil, gas, coal, building material) SEDIMENTARY ROCK TYPES CLASTIC SEDIMENTS: GRAINS PRODUCED BY MECHANICAL OR CHEMICAL WEATHERING AT EARTH'S SURFACE (EXAMPLE: SANDSTONE) BIOCHEMICAL SEDIMENTS: MATERIAL OF ORGANIC (LIVING THINGS) ORIGIN SUCH AS SHELL OR CORAL FRAGMENTS (EXAMPLES: LIMESTONE, COAL) CHEMICAL SEDIMENTS: INORGANIC CHEMICALS PRECIPITATED (CRYSTALIZED) FROM WATER (EXAMPLE: SALT DEPOSITS) Size and shape of sedimentary grains reflects transportation history Beach sand Davidson 4.20 Large grains indicate transport and deposit by strong currents: mountain streams, beaches with large waves, or glacial melt streams SEDIMENTARY ROCK TYPES Deposited by moderate currents that removed finer sediment: rivers, coasts with moderate waves, wind-produced dunes Deposited by gentle currents, so small particles settle out of the water: deep ocean, coasts with weak tides Davidson 4.19 COMPACTION, LITHIFICATION, DIAGENESIS UNCONSOLIDATED SEDIMENT TURNS INTO HARD SEDIMENTARY ROCKS Davidson 4.25 Similar to snow turning to ice Sedimentary Structures: Cross-bedding: sediment carried by moving fluid (water, air) Ripple Marks Graded Bedding: grains become finer upward in layer Mud Cracks: shallow water deposit Davidson 4.24 MIDWEST HAS FEATURES FORMED BY SEDIMENT TRANSPORTED BY GLACIERS MANY FORMED 25,000 14,000 YRS AGO DURING LAST ICE AGE VAST ICE SHEET OVER CANADA GLACIERS FLOW AWAY FROM ICE SHEET'S CENTER 18,000 YRS AGOSOUTHERMOST ADVANCE OF GLACIER THAT FLOWED THROUGH LAKE MICHIGAN BASIN AND INTO NE ILLINOIS SINCE THEN, ICE MELTED BACK QuickTime™ and a Photo decompressor are needed to see this picture MAXIMUM EXTENT OF GLACIATION LAST MILLION YEARS Davidson 14.15 Earth’s orbit changes MILANKOVITCH CYCLES Earth’s tilt changes ECCENTRICITY, TILT, & PRECESSION CAUSE VARIATIONS IN SUNLIGHT (UP TO ABOUT 5% AT HIGHER LATITUDES), SO CLIMATE VARIES BETWEEN WARMER AND COLDER PERIODS COLDER WINTERS, MORE ICE ACCUMULATES, CAN START ICE AGE OTHER FACTORS MAY ACT INCLUDING MOUNTAIN UPLIFT (HIMALAYA) GLACIERS- THICK ICE, LASTS ALL YEAR; RECRYSTALLIZED SNOW MOVES DOWNSLOPE BY GRAVITY OR RADIALLY OUTWARD BY ITS OWN WEIGHT Robeson Glacier, Canada GLACIERS ERODE & DEPOSIT SEDIMENT - TILL ADVANCING GLACIERS SLOWLY PUSH EARTH & ROCK FORWARD DEPOSIT THESE MATERIALS WHEN GLACIERS MELT (RETREAT) TILL - DEBRIS DEPOSITS, POORLY SORTED FORM CHARACTERISTIC LANDFORMS END MORAINES TILL DEPOSITS AT GLACIER MARGIN Sheridan Road, Winnetka Glencoe Beach Glacial Park, McHenry Palos Park Kettle Morraine State Forest, WI DRUMLINS ROUNDED & ELONGATED HILL OF GLACIAL TILL BUILT UNDER ICE MARGINS SHAPED BY GLACIERS FLOW BLUNT NOSE IN DIRECTION FROM WHICH ICE CAME & GENTLE SLOPE TAPERED IN OTHER DIRECTION ESKERS LONG SAND & GRAVEL RIDGES LEFT BY SEDIMENT IN MELTWATER TUNNELS UNDER GLACIER VOLO BOG (McHENRY, IL)A KETTLE LAKE FORMED 15,000 YEARS AGO WITH GLACIER'S RETREAT LEFTOVER LARGE BLOCKS OF ICE ON GROUND MELTS AS CLIMATE WARMS FORMS KETTLE-HOLE DEPRESSION EVENTUALLY FILLS RETREATING GLACIERS; MUCH STILL UNDER ICE ILLINOIS 16,000 YRS AGO RECENTLY DEGLACIATED AREAS COVERED WITH BARE SHEETS OF TILL & SLOWLY REVEGETATED LARGE LAKES WHERE MORRAINES DAM WATER COMING OFF MELTING GLACIERS LAKES, MARSHES, AND BOGS COMMON COOLER CLIMATE- DIFFERENT PLANTS AND ANIMALS THAN TODAY CHEMICAL SEDIMENTS: CRYSTALLIZED FROM WATER WHEN THEIR CONCENTRATION EXCEEDS THAT WHICH CAN BE DISSOLVED (SOLUBLE) IN WATER EVAPORITES - SALTS OF SODIUM, CALCIUM, MAGNESIUM, POTASSIUM DEPOSITED AS DESERT LAKES, SEAS DRY UP EXAMPLESDEAD SEA BONNEVILLE SALT FLATS (GREAT SALT LAKE) REMAIN FROM HUGE LAKE DURING ICE AGES MEDITERRANEAN (6 MYR AGO) GREAT SALT LAKE - UTAH LATEST OF LAKES THAT EXISTED OFF AND ON FOR PAST 15 MYRS NO OUTLET BECAUSE AT BOTTOM OF A BASIN FRESH WATER ENTERING FROM RIVERS CAN ONLY EXIT BY EVAPORATION OR SEEPAGE INTO DEEP GROUNDWATER LAYERS CURRENT CLIMATE OF HIGH EVAPORATION AND LOW INPUT OF FRESH WATER GIVES SALINE LAKE SALT WATERS’ MAJOR ELEMENTS: SODIUM, MAGNESIUM, POTASSIUM, CHLORIDE, AND SULFATE MAJOR MINERAL INDUSTRY QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture 5-6 million years ago the Mediterranean became isolated from the Atlantic Ocean, causing the sea water to evaporate, and leaving immense driedup basins, shown by a large accumulation of salt deposits sandwiched between deep-water marine sediments QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture METAMORPHIC ROCKS- FROM ALTERATION OF PRE-EXISTING ROCKS BY HEAT, PRESSURE, & CHEMICAL REACTIONS CAN INVOLVE CHANGES IN MINERALOGY, TEXTURE, & CHEMICAL COMPOSITION PRESSURE & TEMPERATURE INCREASE WITH DEPTH ALTHOUGH SHALLOW BURIAL CAN PRODUCE LITHIFICATION & DIAGENESIS OF SEDIMENT INTO SEDIMENTARY ROCK, ONLY PLATE TECTONIC PROCESSES CAN CAUSE PRESSURES AND TEMPERATURES HIGH ENOUGH TO PRODUCE METAMORPHIC ROCKS METAMORPHIC ROCKS INDICATE TEMPERATURE & PRESSURE CONDITIONS UNDER WHICH THEY FORMED Davidson 4.26 METAMORPHIC ROCKS: MARBLE HEAT AND PRESSURE METAMORPHOSE LIMESTONE INTO MARBLE Metamorphic rocks formed by increasing pressure/temperature on a mudstone to slate, then schist, then gneiss, then remelted & recrystallized Davidson 4.26 INTERNAL ENERGY (HEAT) FROM EARTH ACTS VIA PLATE TECTONICS TO CAUSE VOLCANISM & MOUNTAIN BUILDING EXTERNAL ENERGY FROM SUN CAUSES WEATHER, THUS WEATHERING, EROSION, TRANSPORTATION, & DEPOSITION OF SEDIMENTS ROCKS BURIED, METAMORPHOSED, MELTED & UPLIFTED BY TECTONIC PROCESSES Davidson 4.30 THE ROCK CYCLEINTERCONNECTIONS BETWEEN ROCK-FORMING PROCESSES [...]... ONLY PLATE TECTONIC PROCESSES CAN CAUSE PRESSURES AND TEMPERATURES HIGH ENOUGH TO PRODUCE METAMORPHIC ROCKS METAMORPHIC ROCKS INDICATE TEMPERATURE & PRESSURE CONDITIONS UNDER WHICH THEY FORMED Davidson 4.26 METAMORPHIC ROCKS: MARBLE HEAT AND PRESSURE METAMORPHOSE LIMESTONE INTO MARBLE Metamorphic rocks formed by increasing pressure/temperature on a mudstone to slate, then schist, then gneiss, then... & DEPOSIT SEDIMENT - TILL ADVANCING GLACIERS SLOWLY PUSH EARTH & ROCK FORWARD DEPOSIT THESE MATERIALS WHEN GLACIERS MELT (RETREAT) TILL - DEBRIS DEPOSITS, POORLY SORTED FORM CHARACTERISTIC LANDFORMS END MORAINES TILL DEPOSITS AT GLACIER MARGIN Sheridan Road, Winnetka Glencoe Beach Glacial Park, McHenry Palos Park Kettle Morraine State Forest, WI DRUMLINS ROUNDED & ELONGATED HILL OF GLACIAL TILL BUILT... and a TIFF (Uncompressed) decompressor are needed to see this picture METAMORPHIC ROCKS- FROM ALTERATION OF PRE-EXISTING ROCKS BY HEAT, PRESSURE, & CHEMICAL REACTIONS CAN INVOLVE CHANGES IN MINERALOGY, TEXTURE, & CHEMICAL COMPOSITION PRESSURE & TEMPERATURE INCREASE WITH DEPTH ALTHOUGH SHALLOW BURIAL CAN PRODUCE LITHIFICATION & DIAGENESIS OF SEDIMENT INTO SEDIMENTARY ROCK, ONLY PLATE TECTONIC PROCESSES... CURRENT CLIMATE OF HIGH EVAPORATION AND LOW INPUT OF FRESH WATER GIVES SALINE LAKE SALT WATERS’ MAJOR ELEMENTS: SODIUM, MAGNESIUM, POTASSIUM, CHLORIDE, AND SULFATE MAJOR MINERAL INDUSTRY QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture 5-6 million years ago the Mediterranean became isolated from the Atlantic Ocean, causing the sea water to evaporate, and leaving immense... TECTONICS TO CAUSE VOLCANISM & MOUNTAIN BUILDING EXTERNAL ENERGY FROM SUN CAUSES WEATHER, THUS WEATHERING, EROSION, TRANSPORTATION, & DEPOSITION OF SEDIMENTS ROCKS BURIED, METAMORPHOSED, MELTED & UPLIFTED BY TECTONIC PROCESSES Davidson 4.30 THE ROCK CYCLEINTERCONNECTIONS BETWEEN ROCK- FORMING PROCESSES ... EVAPORITES - SALTS OF SODIUM, CALCIUM, MAGNESIUM, POTASSIUM DEPOSITED AS DESERT LAKES, SEAS DRY UP EXAMPLESDEAD SEA BONNEVILLE SALT FLATS (GREAT SALT LAKE) REMAIN FROM HUGE LAKE DURING ICE AGES MEDITERRANEAN (6 MYR AGO) GREAT SALT LAKE - UTAH LATEST OF LAKES THAT EXISTED OFF AND ON FOR PAST 15 MYRS NO OUTLET BECAUSE AT BOTTOM OF A BASIN FRESH WATER ENTERING FROM RIVERS CAN ONLY EXIT BY EVAPORATION OR. .. GLACIER VOLO BOG (McHENRY, IL)A KETTLE LAKE FORMED 15,000 YEARS AGO WITH GLACIER'S RETREAT LEFTOVER LARGE BLOCKS OF ICE ON GROUND MELTS AS CLIMATE WARMS FORMS KETTLE-HOLE DEPRESSION EVENTUALLY FILLS RETREATING GLACIERS; MUCH STILL UNDER ICE ILLINOIS 16,000 YRS AGO RECENTLY DEGLACIATED AREAS COVERED WITH BARE SHEETS OF TILL & SLOWLY REVEGETATED LARGE LAKES WHERE MORRAINES DAM WATER COMING OFF MELTING GLACIERS