Here's why layers are so obvious:
* Sedimentation: Sediments like sand, silt, clay, and organic matter are deposited in layers, with the oldest layers at the bottom and the youngest at the top.
* Compaction: Over time, the weight of overlying sediments compresses the lower layers, squeezing out water and air.
* Cementation: Dissolved minerals in the water seep into the spaces between sediment particles, crystallize, and act as a cement, binding the particles together.
Other noticeable characteristics of sedimentary rocks include:
* Fossils: Sedimentary rocks are often the only type of rock to contain fossils, as they form under conditions that preserve organic matter.
* Color: Sedimentary rocks come in a wide range of colors depending on the minerals and materials they contain.
* Texture: The texture of a sedimentary rock depends on the size and shape of the sediment grains, ranging from fine-grained mudstone to coarse-grained conglomerate.
So, while you might notice other things about sedimentary rocks, the layered structure is the most defining and immediately recognizable feature.
