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transform boundary The San Andreas Fault is undoubtedly the most famous transform boundary in the world. To the west of the fault is the Pacific plate, which is moving northwest. To the east is the North American Plate, which is moving southeast. Photograph by Robert E. Wallace, USGS. 1 A tsunami is formed when continental plates shift suddenly as it did last December off the coast of Indonesia. The huge waves killed thousands. 2 collisional ranges The Himalayas, the highest mountains in the world, were created this way. (In fact, they're still growing.) So were the European Alps. Even the Appalachian Mountains formed when two land masses came together. The Swiss Alps The Appalachian’s Blue Ridge Mts. 3 Hawaiian Islands Artist's conception of the movement of the Pacific Plate over the fixed Hawaiian "Hot Spot," illustrating the formation of the Hawaiian RidgeEmperor Seamount Chain. 4 Rocks and The Rock Cycle 3 Main Rock Types Igneous Sedimentary Metamorphic Igneous EXTRUSIVE Forms when lava cools quickly on the Earths surface Forms from molten rock cooling and solidifying INTRUSIVE Magma cools slowly over millions of years deep beneath the surface IGNEOUS---Extrusive Little or NO Crystals! Lava cools on the surface so fast minerals do not get a chance to form Extrusive rocks can be divided into two categories based on color Dark colors black-brownred Light colors white-graypink • Basalt • Obsidian • Rhyolite IGNEOUS---Intrusive Large Interlocking Crystals!!! Magma cools slowly over millions of years… LARGE CRYSTALS FORM Intrusive rocks can also be divided into two categories based on color Dark colors blackbrown-green Light colors white-gray-pink • Gabbro • Granite IGNEOUS---Intrusive Large Interlocking Crystals! Magma cools slowly over millions of years… LARGE CRYSTALS FORM Intrusive rocks can also be divided into two categories based on color Dark colors blackbrown-green Light colors white-gray-pink • Gabbro • Granite Intrusive Igneous Rocks • Formed when magma “inside” the volcano cools s-l-o-w-l-y • Forms large grain crystals Peridotite Gabbro Diorite Granite Pegmatitie Extrusive Igneous Rocks • Formed from lava “exiting” the volcano and cooling quickly • Forms fine-grain crystals Andesite Rhyolite Basalt Obsidian Pumice 3 Main Rock Types Igneous Sedimentary Metamorphic How to make a clastic sedimentary rock Weathering and Erosion Transportation Compaction and Cementation Deposition Sedimentary Rock Sedimentary rocks are divided into three categories Chemical Mechanical Organic (Clastic) (Biologic) Minerals are dissolved in the water…water is evaporated off and leaves behind chemical sedimentary rocks Examples are Halite, Limestone and Gypsum Sedimentary rocks are divided into three categories Chemical Mechanical (Clastic) Organic (Biologic) Made from eroded fragments of other rocks Shale Microscope grains of mud cemented together Sandstone Sand grains cemented together Conglomerate Pebble to boulder size fragments cemented together Sedimentary rocks are divided into three categories Organic Mechanical (Clastic) Chemical (Biologic) Rocks are formed from the remains of plants and animals which have hardened Oil (animal remains) Coral (sea mammals) Coal (dead plant material) Continental environments – alluvial fan Sedimentary rocks, environments and structures Continental environments – eolian deposits Sedimentary rocks, environments and structures Sedimentary Facies (facies – the character of a rock defined by its formation, composition and fossil content) Sedimentary rocks, environments and structures Transitional environments – deltas Sedimentary rocks, environments and structures A bedding plane is the line separating one layer of compressed rock from the next layer of compressed rock. Sedimentary structures – bedding planes Sedimentary rocks, environments and structures Sedimentary structures – graded bedding Sedimentary rocks, environments and structures Sedimentary structures – graded bedding Sedimentary rocks, environments and structures Sedimentary structures – mud cracks Sedimentary rocks, environments and structures 3 Main Rock Types Igneous Sedimentary Metamorphic Metamorphic rocks form from HEAT&PRESSURE Two types of metamorphism Contact Rock surrounding a magma body gets cooked and changes Regional Tectonic forces Metamorphism occurs over a large area Contact Metamorphism is the ZONE _________ of contact where an Igneous Intrusion meets the existing rock but DOES NOT melt it. ________ Contact Metamorphism Deep underground, zones of metamorphism form around the hot magma of batholiths. L.Gardiner/Windows Original CONTACT METAMORPHISM Contact metamorphism occurs only at the place where the magma contacts rock SHALE SANDSTONE LIMESTONE SANDSTONE IGNEOUS INTRUSION Regional Metamorphism: occurs over large areas with extreme pressures & temperatures Regional Metamorphism Tectonic forces smash continents together. The rocks get heated and become semi-molten. The added pressure causes the mineral to separate into bands and sometime to even flow before cooling again! This extreme heat and pressure is what builds MOUNTAINS PARENT ROCK Is the rock from which metamorphic rock is formed. Common Metamorphic Rocks Parent Rock Metamorphic Rock Granite (Igneous Intrusive) Gneiss Shale (Sedimentary) Slate Sandstone (Sedimentary) Quartzite Parent Rock Metamorphic Rock Limestone (sedimentary) Marble Extrusive Igneous A Metamorphic rock is one whose original form has been changed by heat and pressure. This change is called re-crystallization. These changes are not caused by melting. If the rock melted and cooled it would be an Igneous Rock. Changes caused by re-crystallization may include the creation and growth of new mineral crystals. Rocks which are intensely compressed (pressure) can also become metamorphic. Becomes more dense and resistant to weathering The growth of new minerals may cause the rock to appear banded or foliated stripes of light and dark minerals. SCHIST SHOWS BANDING pressure pressure pressure DISTORT It can also ____________ (BEND) OR DESTROY ______________ ORIGINAL STRUCTURES The Rock Cycle 48 49 Tectonic Forces: Intrusive Landforms Batholith Laccolith Sill Dyke Mesa’s & Buttes Constructing a Rock Cycle Melts at high temp MAGMA (Molten Rock) Metamorphic Cools & Crystalises Igneous Weathers & Erodes Extreme Heat & Pressure Sedimentary Sediment Compressed and compact