GEOLOGICAL HISTORY OF CANAD Essay Example | Topics and Well Written Essays - 1000 words

GEOLOGICAL HISTORY OF CANAD - Essay ExampleThe first class consists of sedimentary jousts which form the Earths surface. Some consist of fragments that vary in range and atomic number 18 eroded from olderrocks and deposited as gravel, sand or mud and are then consolidated by burial yieldingconglomerate, sandstone or shale respectively. Others comprise of chemic deposits, for example gypsum or rock salt, which resulted from evaporation of seawater. Still others result from biological activities, for instance cemented shell fragments or coral reefs form limestone. Sedimentaryrocksmakeupthe eastmost ranges of the Canadian Cordillera known as the Mackenzie, Rocky and Franklin mountains, but are common in the occidental Cordillera as well. Many sedimentary rockshave petrified cadaver of animals and plants (fossils), and olderrockscontain diverse kinds of fossils compared to youngerrocks.Igneousrocksoriginated deep deep down the Earth as molten rock or magma. Magma that solidified de ep within the earth formed platonic rock such as granite, which is a common rock particularly in the coast mountains of the western Cordillera and are astray distributed elsewhere. Magma that emerged as lava and cooled at the Earths surface formed a variety of volcanic rock, which is widespread in the interior plateau region and elsewhere in the western Canadian Cordillera.Metamorphicrocksformed when igneousor sedimentary rockswere buried deep within the Earth during mountain formation. New minerals grew while old features of the rock were destroyed in response to the high temperatures and pressures encountered in the Earths core. Consequently, limestone changed to marble, shale to schist, and platonic rock to gneiss. Metamorphicrocksare common in the Shuswap Highland, the Coast Mountains and the Columbia, Omineca and Cariboo ranges of the eastern Cordillera. The presence of metamorphicrocksat the surface is the evidence of those parts of the