Context - In a recent study in the journal Sedimentologika, researchers documented a new kind of sedimentary rock made from coastal slag deposits in the U.K.
What is slag?
- It is a composite material containing metal oxides and silicon dioxide and is a by-product of the steelmaking process in the iron and steel industries.
- Slag is a major component of artificial ground.
- The lithification process hardens industrial waste, including slag, into sedimentary rocks, creating artificial ground.
- When these sedimentary rocks weather over time, they release sediments into the environment.
- Because the rocks are infused with industrial waste, their sediments often contain toxic metals that contaminate soil, water, and air.
What is a sedimentary rock?
Sedimentary rocks are formed from pre-existing rocks or pieces of once-living organisms. They form from deposits that accumulate on the Earth's surface. Sedimentary rocks often have distinctive layering or bedding.
- Clastic Sedimentary Rocks: made up of pieces (clasts) of pre-existing rocks. Pieces of rock are loosened by weathering, then transported to some basin or depression where sediment is trapped. If the sediment is buried deeply, it becomes compacted and cemented, forming sedimentary rock. Eg – shale.
- Biologic sedimentary rocks form when large numbers of living things die. Chert is an example for this type of rock, and this is one of the ways limestone can form. Limestone can also form by precipitating directly out of the water.