Sedimentary Rocks are types of rocks formed when tiny pieces of minerals, rocks or organic material settle in layers. There are five stages and a lot of time involved in the formation of sedimentary rock; weathering, erosion, deposition, compaction and cementation.
- Clastic Sedimentary Rocks include Sandstone (primarily sand), Shale (composed of clay and silt in fine layers) and Conglomerate (rounded gravel particles cemented together.)
- Chemical Sedementary Rocks include Limestone (calcium carbonate from marine water or accumulated from biological sources), Rock Salt (formed by evaporation of saline water leaving salt crystals) and Chert (microcrystaline quartz or accumulation of silica skeletons)
- Organic Sedementary Rocks include Coal (formed from compressed plant debris) and Certain Limestone (formed from the accumulation of shells, coral or other marine organic remains.)
A Rock Outcropping is where bedrock or sedimentary rock is visible on the Earth's surface. It takes a lot of force to remove soil and other covering material and expose these layers. Outcroppings are mainly exposed due to erosion, weathering or excavation.
Sedimentary Rocks are those that form in orderly layers. If the layers of the rock are Planar, or horizontal, with a constant thickness then these rocks are said to have a "Layer-cake" stratigraphy.
Stratigraphy: referrs to the order and relative position of Strata.
Strata: includes layers or a series of layers of rock.
A Bed is a term referring to individual layers within the rock.
Geological Units are a collection of adjoining beds that are grouped together when they have some similarity in composition, or similar structures or patterns that indicate a common process in their formation.
Outcrop patterns are the visible expression of rocks and geological features on the earth's surface.There are horizontal strata and vertical clefts in these rocks and I always see something new. I have walked past this formation so many times and I always stop to admire it. The sun sets early in this specific location because the outcropping is high and to the west. There is a spot nearby to sit and answer some questions, or just enjoy the view. Thanks for visiting.
REQUIREMENT QUESTIONS: Send answers 1-4 before logging.
1. Do you think this rock outcropping was exposed due to Erosion, Weathering or Excavation?
2. What type of sedimentary rock do you believe is visible in this outcrop? Clastic, Chemical or Organic? What subtype?
3. Field Trip: At the waypoint provided is a small cavern. Describe the difference between the strata on the left and right walls of the cavern. What do you think caused this difference? How do you think this small cavern was formed? Which side, if any, would you consider to have a "layer-cake" stratigraphy?
4. What type of vegetation do you see on top of the rock outcropping? What type of vegetation do you see at the bottom or foot of the outcropping?
5. Take a picture of yourself or a personal item from any angle at this location to add to your log.