英和和英

出典:『Wikipedia』 (2011/02/01 06:53 UTC 版)

英語による解説

引用

Parent rock refers to the original rock from which something else was formed. It is mainly used in the context of soil formation where the parent rock will have a large influence on the nature of the resulting soil. The term is also used in the context of metamorphic rocks where again the parent rock refers to the original rock before metamorphism takes place. Parent Rocks can be sedimentary, igneous or metamorphic.(ex.- shale becomes slate, granite becomes gneiss etc.) In these cases, parent rock may be referred to as the protolith. Parent rock is the main source of soil. This type of soil is also called residual soil. Different parent rocks have different chemical compositions. The Parent Rock is also known as bedrock and is made mostly of solid rocks, there is no weathering occurred there because the roots of the plant can not go that deep. It is the third layer and is underneath Topsoil and Subsoil. The parent rock has little organic matter.