2、间图中的 Earth in Space and Time 4)理的造与組成 环质 Environmental Geology
环境地质学 Environmental Geology 4）地球的构造与组成 2、时空中的地球 Earth in Space and Time
5)理的演化 Earth, then andino A、(地球的初始无序形态:无海洋、无大气) The early earth was very different from what it is today, lacking the modern oceans and atmosphere and having a much different surface from its present one, probably more closely resembling the barren, cratered surface of the moon. The planet was heated by several processes: the impact of the colliding dust particles and meteorites as they came together to form the earth, compression of the interior by gravity(that materials heat up when compressed can be demonstrated by pumping up a bicycle tire and then feeling the barrel of the pump 1), and energy release from decay of the small amounts of several naturally radioactive elements that the earth contains 环质 Environmental Geology
环境地质学 Environmental Geology 5）地球的演化 Earth, then and now A、(地球的初始无序形态：无海洋、无大气） The early earth was very different from what it is today, lacking the modern oceans and atmosphere and having a much different surface from its present one, probably more closely resembling the barren, cratered surface of the moon. The planet was heated by several processes: the impact of the colliding dust particles and meteorites as they came together to form the earth, compression of the interior by gravity (that materials heat up when compressed can be demonstrated by pumping up a bicycle tire and then feeling the barrel of the pump①), and energy release from decay of the small amounts of several naturally radioactive elements that the earth contains
5)恐珍的演化 Earth, then and now B、(地球的初始无序形态一三类热源、使之熔化、分异 These three heat sources combined to raise the earth's internal temperature enough that parts of it, perhaps eventually most of it, melted although it was probably never molten all at once. Dense materials, like metallic iron would have tended to sink toward the middle of the earth As cooling progressed, lighter, low-density mineral crystallized and floated out toward the surface. the eventual result was an earth differentiated into several major compositional zones; the central core; the surrounding mantle, and a thin crust at the surface(fig 1.1.1). The process was complete before 4 billion years ago.(四十亿年前) 环质 Environmental Geology
环境地质学 Environmental Geology 5）地球的演化 Earth, then and now B、(地球的初始无序形态－三类热源、使之熔化、分异） These three heat sources combined to raise the earth’s internal temperature enough that parts of it, perhaps eventually most of it, melted, although it was probably never molten all at once. Dense materials, like metallic iron, would have tended to sink toward the middle of the earth. As cooling progressed, lighter, low-density mineral crystallized and floated out toward the surface. The eventual result was an earth differentiated into several major compositional zones; the central core; the surrounding mantle; and a thin crust at the surface (fig1.1.1). The process was complete before 4 billion years ago.（四十亿年前）