Rocks, Rocks, and more Rocks - Sedimentary. Sedimentary rocks are classified by the types of sediments that make up the rock. What are sediments?. Definition: Small, solid pieces of material that come from rocks or living things like bones, leaves, stems, etc. Sizes of Sediments.
Sedimentary rocks are classified by the types of sediments that make up the rock
Step 1: EROSION (wash away)
Forces of running water, wind, or ice that loosen & carry away fragments of rock
Can you see the sediment moving in the water?
Have you ever seen sediments being moved during a hard rain?
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.
Process that presses sediments together. Thick layers of sediment build up over time & weigh down the layers compacting them.
Dissolved minerals seep into spaces between particles (sediments) & then crystallize as they harden.
Made from fragments that are squeezed together
Forms from mud - tiny clay particles, quartz & calcite;
Forms from sand on beaches, ocean floor, river beds, etc
From rounded sediments
From larger, sharp fragments
2. Organic Sedimentary Rock
Forms where the remains of plants & animals are deposited in thick layers
From swamp plants buried in water for millions of years (plants peat coal)
Forms 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 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.
3. Chemical Sedimentary Rock
Forms when minerals that have been dissolved in a solution with water, crystallize
Another form of limestone forms from calcite in seas, lakes & underground caves – forms caverns & sinkholes in the ground when it is eroded by ground water
Forms from halite when evaporation leaves salt behind
600 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?
FOSSILS are always found in Sedimentary Rock ONLY!
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…
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.
Some great resources for Sedimentary Rocks & more: lived on Earth for millions of years…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!