What rock has strata?

Answer 1

Strata are groups of sedimentary bedding planes which were created by a multitude of occurrences. One example:

1. A watershed feeds surface water to a stream. As the slightly acidic surface water flows over rocks and soil, it picks up small bits and pieces of rock and organic matter and interacts chemically with rock, dissolving some of its constituent minerals.

2. The stream flows into a river. The river has a greater capacity to carry sediments, from those that are dissolved in the water, through boulder-sized rocks, depending on the river's turbulence, velocity, and other factors.

3. When the river flows into an ocean or lake, the velocity of the flow is greatly reduced, and the sediments being carried by the water will be deposited on the ocean or lake floor; larger sediments are the first to succumb to friction and gravity while suspended sediments are carried further away from the shore.

4. This deposition of sediments is an ongoing process. The amount and type of sediment may vary seasonally, or from any of a variety of causes. Over long periods of time, these multiple varying layers are covered with massive amounts of additional sediments, which compact them, squeezing out the water and spaces between the individual particles.

5. Given enough time and weight from overlying sediments, cementing minerals "precipitate" from the disappearing fluids surrounding the sediment particles. When the individual particles are cemented together, sedimentary rock is formed, and in this instance, strata will be visible in the sedimentary rock as a record of a periods of deposition.

Answer 2

In geology and related fields, a stratum (plural: strata) is a layer of rock or soil with internally consistent characteristics that distinguishes it from contiguous layers. Each layer is generally one of a number of parallel layers that lie one upon another, laid down by natural forces. They may extend over hundreds of thousands of square kilometers of the Earth's surface. Strata are typically seen as bands of different colored or differently structured material exposed in cliffs, road cuts, quarries, and river banks. Individual bands may vary in thickness from a few millimeters to a kilometer or more. Each band represents a specific mode of deposition-river silt, beach sand, coal swamp, sand dune, lava bed, etc.

Answer 3

Strata is plural, stratum is singular. A stratum (a.k.a. bed) is the smallest unit used in litho-stratigraphy (~writing by the rocks). A cm to m sized layer of sedimentary rock bounded above and below by bedding planes.

Answer 4

Sedimentary Rocks

Answer 5

Sedimentary rock.