Sedimentary Rock Basics

transported using moving water. Groundwater is good for ions, but not as good for solids. Wind and glaciers will be good transporters of solid sediment. Transport sorts out particles by their velocity and helps to round the sediment.

At some point, the energy put into transportation of sediment runs out. Only so much energy is in a stream. After a heavy rain, more energy will be in the stream than you'll see in times when the stream has less water in it. Large sediments are more likely to get deposited near the source of their origin than smaller sediments. Usually, sediments that are alike in size will get deposited together. All layers get deposited horizontally as you already know.

Sorting tends to separate the suspended sediments. Finer sediments stay in suspension longer and will end up further out from a river mouth or beach. Clay is seen in deeper water, while sand is seen along the beach.

Ions will crystallize if the concentration gets high enough to supersaturate them, such as with evaporation. Halite (which is table salt) and gypsum (which is calcium sulfate) are both made this way. Seas and certain salty lakes will have this issue.

As sediments get deposited, they get packed down so that there is no space for water anymore. There are dissolved minerals that then crystallize out from the preexisting water to cement the rest of the sediments. Silica, hematite, and calcite are all good cementers used to make rock from sediment.

SEDIMENTARY ROCK BASICS

You should know the terminology regarding sedimentary rocks. The material that gets washed off during erosion is called detritus. These can be large or small and can only get transported if enough energy is involved. As the energy drops, the detritus becomes sediment. This ordinary type of sedimentation is known as clastic sedimentation. Material that gets dissolved in water and then precipitates out is called chemical sediment, or chemical sedimentation. Then you've got biochemical sedimentation, where seashells and bones are dissolved and then precipitate out. Lastly, you have organic sediment, which is the stuff in plants and animals that form fossils over time or become decomposed enough to be the gunk that coal is made from.