4 Sediments will layer up over time, forming layered rocks
5 There are 4 main processes needed to form sedimentary rock: Step 1: EROSION (wash away) Forces of running water, wind, or ice that loosen & carry away fragments of rockCan you see the sediment moving in the water?Have you ever seen sediments being moved during a hard rain?
6 There are 4 main processes needed to form sedimentary rock: Step 2: DEPOSITION (drop down) Sediments settle out of the water or wind carrying them & settle to the bottom of a lake or ocean.Sediments move down the sloped land & settle at the bottom.Over time these sediments layer up.
7 There are 4 main processes needed to form sedimentary rock: Step 3: COMPACTION (smashed together) Process that presses sediments together. Thick layers of sediment build up over time & weigh down the layers compacting them.
8 Those smashed sediments can form into layers like the ones shown above.
9 There are 4 main processes needed to form sedimentary rock: Step 4: CEMENTATION (glued together) Dissolved minerals seep into spaces between particles (sediments) & then crystallize as they harden.
11 3 Types of Sedimentary Rocks Clastic Sedimentary RockMade from fragments that are squeezed together
12 Comparing 2 Clastic Sedimentary Rocks: ShaleForms from mud - tiny clay particles, quartz & calcite;SandstoneForms from sand on beaches, ocean floor, river beds, etc
13 Comparing 2 more… Conglomerate Breccia From rounded sediments From larger, sharp fragments
14 3 Types of Sedimentary Rocks 2. Organic Sedimentary Rock Forms where the remains of plants & animals are deposited in thick layers
15 Comparing 2 Organic Sedimentary Rocks LimestoneForms from hard shells w/calcite from seashells, coral, clams, oysters or skeletons that pile up on the ocean floor for millions of years slowly changing the sediment to limestoneCoalFrom swamp plants buried in water for millions of years (plants peat coal)
16 Use for coal & a location of limestone… ***Plant Bowen is a power plant that uses coal. Has anyone seen this before? It’s not too far away!Limestone in England where there was once H2O covering the land.
17 3 Types of Sedimentary Rock 3. Chemical Sedimentary Rock Forms when minerals that have been dissolved in a solution with water, crystallize
18 Examples of Chemical Sedimentary Rock Limestone ***Another form of limestone forms from calcite in seas, lakes & underground caves – forms caverns & sinkholes in the ground when it is eroded by ground waterRock SaltForms from halite when evaporation leaves salt behind
19 Comparing 2 Chemical Sedimentary Rocks Limestone***Rock Salt600 million year old rock salt being mined in the Himalayan Crystal Rock Mine.Ruby Falls cave is made of limestone! How did the cave form?
20 Uses: What things have been made from Sedimentary Rock? Flint: ArrowheadsSandstone: THE WHITE HOUSELimestone: Blocks & slabs for building, making cement & steel, flooring
21 Possibly the coolest thing about Sedimentary Rock… FOSSILS are always found in Sedimentary Rock ONLY! Why???
22 Fossils are the signs of the plants & animals that have lived on Earth for millions of years… sometimes we see the whole creature or actual parts of the plant… sometimes we see evidence that a creature lived…
25 “Law of Superposition” states that new sediment layers are added on top of older rock layers on the bottom
26 What is the correct order of the layers from OLDEST to YOUNGEST?
27 Law of Superposition states that older rock layers are at the bottom. If there is tectonic plate movement or if an Igneous rock intrusion breaks through the rock layers, then the order is disrupted.Oldest: F Next: E What happened with layer D? Then: C, B, A What is happening over & on top of layer A?
28 How can fossils help us determine the relative age of rocks?
29 Some great resources for Sedimentary Rocks & more: Additional resources can be found on my webpage. You can also use the internet to search the topic you are interest in. Lots of great stuff out there!Geology More Geology Science Articles Sedimentary Rocks