geology

Geology is the science concerned with the Earth's materials, structure, processes, and history. It studies rocks, minerals, fossils, landforms, and the dynamic interactions that shape the planet over time. Geology integrates field observations with laboratory analyses and theoretical models to understand how Earth formed, evolved, and will change in the future.

Geology is often divided into branches such as physical geology, which examines the materials composing the Earth and the processes that operate on them (weathering, erosion, volcanism, and tectonics); historical geology, which investigates the origins and development of Earth through geological time; and subdisciplines like mineralogy, petrology, sedimentology, geomorphology, paleontology, stratigraphy, and geochronology. The study also includes geophysics and geochemistry, which apply physical and chemical principles to Earth; hydrogeology and engineering geology, which address water resources and construction-related problems; and economic or environmental geology, which look at resources and environmental impacts.

Geologists employ field mapping, stratigraphic and structural analysis, sampling, petrography, radiometric dating, isotope geochemistry, and remote sensing. Laboratory techniques include microscopy, mass spectrometry, X-ray diffraction, and seismic imaging. Data from fossils, rock records, and proxies are synthesized to reconstruct past environments and large-scale processes.

Core concepts include the rock cycle (interrelationship of igneous, sedimentary, and metamorphic rocks), plate tectonics, and the distribution of Earth’s materials within crust, mantle, and core. Surface processes such as weathering, erosion, and sedimentation shape landscapes, while internal processes drive volcanism, earthquakes, and mountain building.

Geology provides essential insights into natural resources, natural hazards, environmental stewardship, and climate history. The geologic time scale is used to describe Earth's history from its formation to the present, with the fossil record and isotopic dating methods anchoring the chronology.