jarðfræði

Jarðfræði is the scientific study of the Earth, its composition, structure, physical properties, history, and the processes that shape it. It encompasses a wide range of disciplines, including geology, seismology, volcanology, and paleontology.

The Earth's structure is broadly divided into three main layers: the crust, the mantle, and the core. The crust is the outermost solid shell, which is relatively thin and brittle. Beneath the crust lies the mantle, a thick layer of hot, dense rock that behaves like a viscous fluid over geological timescales. At the Earth's center is the core, composed primarily of iron and nickel, with a solid inner core and a liquid outer core.

Geological processes are driven by internal heat from the Earth's core and external energy from the sun. Plate tectonics, a fundamental concept in earth science, explains the movement of large segments of the Earth's crust, known as tectonic plates. The interactions between these plates at their boundaries are responsible for phenomena such as earthquakes, volcanic activity, and mountain formation.

The study of rocks and minerals is central to jarðfræði. Rocks are classified into three main types: igneous, sedimentary, and metamorphic, each formed through different geological processes. Minerals are the naturally occurring inorganic solids with a definite chemical composition and a crystalline structure.

Jarðfræði also investigates the Earth's history through the examination of rock formations, fossils, and other geological evidence. This historical perspective allows scientists to understand past climates, the evolution of life, and the development of landscapes over millions of years. The field has numerous practical applications, including the exploration for natural resources like minerals, oil, and gas, as well as hazard assessment and mitigation related to earthquakes and volcanic eruptions.