Sedimentary and Metamorphic rocks Chapter 6 page 120 Objectives: 1. Learn how sedimentary rocks form 2. Learn how metamorphic rocks form Learn how rocks continuously change from one type of rock into another Indentify various sedimentary rocks based on their characteristics. Identify various metamorphic rocks based on their characteristics.

I. Weathering -the break down of rocks A. Chemical weathering 1. When a rock is chemically changed a) If minerals get dissolved i. Acid dissolves limestone ii. Burning paper is a chemical change 2. Occurs most in warm moist climates

a) The rock is broken down but not chemically altered B. Physical (mechanical) weathering 1. When a rock is physically changed a) The rock is broken down but not chemically altered i. Frost action (wedging) 2. Occurs in areas of alternating temperatures with moisture

C. Weathering produces clastic (broken) sediments 1. Sediments are broken pieces of rock 2. The size of the sediment determines type of sedimentary rock a) page 122 in text or pg 7 in ESRT’s

II Erosion the removal and transport of fragments A . Agent of erosion: what moves particles 1) Wind 2) Moving water 3) Gravity 4) Glaciers 5) Animals

B. Deposition: when particles are laid down 1. Deposited on the ground 2. Sink to bottom of water

C. Burial: when layers upon layers of sediments form 1. The bottom layers has high heat and pressure D. Lithification: Process which sediments turn to stone 1. Caused by heat and pressure of overlying layers a) Lithos is Greek for stone 2. Cementation: When mineral growth cements grains together a) There are two types i. A new mineral grows between grains ii. The same mineral grows between grains

III Features of sedimentary rocks A. Horizontal bedding is primary feature 1. This is called bedding a) Graded bedding: Particles become more coarse and heavy towards the bottom. i. Because large and heavy settle first Cross bedding pic pg 126

b) Cross bedding: form as incline layers of b) Cross bedding: form as incline layers of sediment move forward across a horizontal surface

c) Ripple marks form when sediment is moved into c) Ripple marks form when sediment is moved into small ridges by wind or wave action

IV. Evidence of past life A. Fossils: Preserved evidence of past life 1. Remains 2. Impressions.

V Clastic Sedimentary Rocks A. Formed from deposits of loose sediments 1. Most common sedimentary rocks on Earth 2. These rocks are classified by particle size pg 128 a) Coarse-grained ( 0.2cm and up ) i. Conglomerates: round fragments -evidence of long travel ii. Breccia: angular fragments -evidence of short travel

b) Medium-grained ( 0.006 cm - 0.2 cm ) i. Sandstone forms -Sandstone has a high porosity, many open spaces -Water can flow through these spaces -Sandstone is a natural water filter

c) Fine-grained (0.006 cm and below) i. mud and silt form mudstone and siltstone ii. silt and clay form shale

VI Chemical Sedimentary Rocks A. Rocks form from evaporation 1. Mineral rich water evaporates, leaving crust. a) Most common in arid regions i. Ex: salt in glass of water that sits out ii. page 130 in text to see diagram

B. Organic Sedimentary Rocks 1. Form from the remains of once living things a) limestone is the most abundant i. Marine animals use calcite in water to build shells ii. These shells deposit, layer, and lithify into rocks iii. Limestone will fizz with acid due to its composition of CaCO3 (calcite!)

2. Coal is another Organic Sedimentary rock a) Forms from plant remains i. Over time vegetation accumulates in swamps and coastal areas ii. Called fossil fuel because it was alive once and takes millions of years to form

VII Sedimentary Rock Charts A. Broken into two charts 1. Inorganic Land-derived Sedimentary rocks 2. Chemically and/or Organically formed Sedimentary Rocks

B. There are six columns 1. Texture 2. Grain Size (how clastic rocks are classified) 3. Composition (what it is made of) 4. Comments (lots of useful info here) 5. Rock Name 6. Map Symbol (This is how they draw it)

VIII Metamorphic Rocks A. Causes and types of metamorphism 1. Heat (contact metamorphism) a) From lava or Magma b) Hot water (hydrothermal) c) From depth within the Earth’s crust 2. Pressure (regional metamorphism) a) Regions of land colliding

B. Metamorphic textures 1. Foliated - Wavy layers and bands of minerals 2. Nonfoliated- lack mineral grains with long axes in one direction. .a ) Often with minerals with large blocky crystal shapes.

3. Porphyroblasts- Some minerals grow large 3. Porphyroblasts- Some minerals grow large while surrounding minerals remain small. C. Mineral and compositional changes 1. Solid state alterations- Minerals in the rock change to new minerals that are stable under new temperature and pressure conditions

2) Most rocks keep their original chemical composition. 3) Some change their composition through hydrothermal metamorphism where minerals are exchanged and replaced D. The Rock Cycle 1) Any type of rock can change to any other type of rock over time

1. In which type of climate is chemical. weathering dominate. 2 1. In which type of climate is chemical weathering dominate? 2. Name 2 agents of erosion. 3. How are clastic rocks classified? 4. What are the 2 main causes for rocks to become metamorphic? 5. Define Foliation Bonus: Which rock has banding?

1. Which sedimentary rock will fizz with acid? 2. How do clastic rocks such as sandstone form? 3. What is coal made of? 4. What rock was slate made from? 5. Which rock is shiny from microscopic mica crystals? Bonus: Why are rocks more dense if they are formed from regional metamorphismn instead of contact?