Bell Ringer Igneous rocks are classified by their ________ composition and their ________ size. If you were given a rock high in silica and with small grains, you could conclude that it was [ felsic / mafic ] and [ intrusive / extrusive ]. Quiz TOMORROW (2.1-2.4) (Chemistry – Rock Cycle) Chemical/mineral grain

Sedimentary & Metamorphic Rocks

Part 1: Sedimentary Rocks

Making Rocks into Sediments Clastic Sediments – small pieces of broken-down rocks (clastic = “broken”)

Making Rocks into Sediments These sediments can be cemented together into sedimentary rocks Sedimentary rocks are the most common rocks along Earth’s surface

Making Rocks into Sediments Weathering – the breaking down of rocks into sediment Erosion – the transport of sediment from one place to another (via wind, water, glaciers, or gravity) Deposition – the depositing (dropping, settling) of sediment in one location E W D

Making Sediments into Sedimentary Rocks Lithification – the process of changing sediments into sedimentary rocks L E W D

3 Steps to Lithification Burial – new layers of sediment fall on older layers Compaction – the weight of the new layers on top presses down the older, bottom layers Cementation – substances begin to fill in the spaces between the sediments, cementing them together

Making Sediments into Sedimentary Rocks

Features of Sedimentary Rocks Bedding – horizontal layering Cross bedding – inclined layers formed as sediment spills over a surface

Features of Sedimentary Rocks Graded bedding – when sediment sizes become progressively larger towards the bottom layers Often found in marine sedimentary rocks deposited by underwater landslides. As the sliding stops, the largest/heaviest sediments settle first, followed by progressively smaller particles

Features of Sedimentary Rocks Fossils – preserved examples of past life, only found in sedimentary rocks Why not igneous or metamorphic?

Classification of Sedimentary Rocks 3 Main Types: Clastic – result from the lithification of sediments Most common type of sedimentary rock

Classification of Sedimentary Rocks Sub-classified by particle size: Coarse-grained – large (gravel-sized) sediments Ex: conglomerate Medium-grained – medium (sand-sized) sediments Ex: sandstone Fine-grained – small (silt and clay-sized) sediments Ex: shale

Classification of Sedimentary Rocks Chemical – result from evaporation of precipitate crystals (evaporites) Most commonly found in arid (dry) regions and in oceans and drainage basins with low water flow Examples: rock salt, gypsum

Classification of Sedimentary Rocks Organic – form from the remains of living organisms Examples: limestone, coal

Uses of Sedimentary Rocks Source of fossil fuels (coal, natural gas, oil) Source of uraninite (ore that contains uranium, used in nuclear energy) Building materials (ex: limestone, sandstone, phosphate)

Part 2: Metamorphic Rocks

Metamorphic Rocks Metamorphic rocks – formed when increased temperature and pressure changes rocks without melting them The name comes from the Greek words “meta” (change) and “morphe” (form) Metamorphism causes rocks to change texture, mineralogy, and/or chemical composition Any type of rock (igneous, sedimentary, or even other metamorphic rocks) can undergo metamorphosis and become a metamorphic rock

Example: limestone (sedimentary rock) turns into marble (metamorphic rock)

Metamorphic Rocks The high temperatures needed for metamorphism can happen in two ways: When rocks get buried deep inside the Earth When rocks near Earth’s surface come in contact with rising magma

Metamorphic Rocks The high pressures needed for metamorphism can happen in two ways: Vertical pressure caused by the weight over overlying rock Collision of large pieces of rock during mountain-formation

Different temperature/pressure combinations produce different types of metamorphic rocks

3 Types of Metamorphism Regional metamorphism – when high temperatures and pressures affect large areas deep within Earth’s crust, creating large belts of metamorphic rocks

3 Types of Metamorphism Contact metamorphism – when a small pool of magma below Earth’s surface comes in contact with surrounding rocks and causes them to undergo metamorphism Affects smaller areas (ex: areas under volcanoes) than regional metamorphism

3 Types of Metamorphism

3 Types of Metamorphism Hydrothermal metamorphism – when very hot water reacts with rock and alters its chemistry and mineralogy Can dissolve minerals, break them down, and/or deposit new minerals Occurs in mid-ocean ridges and around volcanoes

Classification of Metamorphic Rocks Two main types: Foliated – have layers or bands of minerals High pressure causes minerals with flat crystals to form with their long axes perpendicular to the pressure Examples: gneiss (from granite), schist (from shale)

Classification of Metamorphic Rocks Non-foliated – lack distinct layers because minerals have blocky shapes Examples: quartzite (from sandstone), marble (from limestone) Foliated Gneiss Non-foliated Quartzite

Part 3: Bringing it all Together The Rock Cycle

Rock Cycle The rock cycle is a cycle…no matter is created or destroyed, just recycled Any type of rock can turn into any type of rock!

Rock Cycle BYOD Use the website to answer the questions ALL the information you need to answer the questions is on the website Put in basket when complete Study for quiz

Finish Igneous Rock lab. When done, clean materials up and study for quiz (mandatory)