Melbourne property prices have passed Sydney as the nation's fastest growing, although they still lagged well behind in terms of absolute cost. Melbourne's year-on-year dwelling price growth of 11 per cent is the nation's fastest. Sydney's annual property price growth of 10.5 per cent is the slowest in 29 months. Less than half the properties auctioned in Sydney over the weekend sold.
How Is Chalk Formed. Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. It forms under relatively deep marine conditions from the gradual accumulation of minute calcite plates (coccoliths) shed from micro-organisms called coccolithophores. It is common to find flint and chert nodules embedded in chalk.
Sedimentary rocks include common types such as chalk, limestone, sandstone, clay and shale. Sedimentary rocks cover 75% of the Earth's surface. Four basic processes are involved in the formation of a clastic sedimentary rock: weathering (erosion)caused mainly by friction of waves, transportation where the sediment is carried along by a current, deposition and compaction where the sediment is squashed together to form a rock of this kind. Sedimentary rocks are formed from overburden pressure as particles of sediment are deposited out of air, ice, or water flows carrying the particles in suspension.