Tag Archive for Chalk

Chalk ( /ˈtʃɔːk/) is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates (coccoliths) shed from micro-organisms called coccolithophores. It is common to find chert or flint nodules embedded in chalk. Chalk can also refer to other compounds including magnesium silicate and calcium sulfate.
Chalk is resistant to weathering and slumping compared to the clays with which it is usually associated, thus forming tall steep cliffs where chalk ridges meet the sea. Chalk hills, known as chalk downland, usually form where bands of chalk reach the surface at an angle, so forming a scarp slope. Because chalk is porous it can hold a large volume of ground water, providing a natural reservoir that releases water slowly through dry seasons.
The Chalk Group is a European stratigraphic unit deposited during the late…

Chalk TX Skateboard Lessons!

Learn Skateboarding in a Two Week-Long Class

Skateboarding is a recreational activity, an art form, or a method of transportation. Skateboarding has been molded and influenced by many skateboarders throughout the ages. A 2002 survey and study by American Sports Data uncovered that there were 18.5 million skateboarders in the world. 85 percent…