Knowra Deep time Deep time Deep time is geological time on scales vastly longer than human history, encompassing the formation and transformation of Earth across billions of years.
Geologic time scale : A system dividing Earth's history into eons, eras, periods, epochs, and ages. Its hierarchy makes immense durations and major transitions easier to organize.
Plate tectonics : The theory that Earth's lithosphere is divided into moving plates above the mantle. Plate motions rearrange continents and ocean basins over millions of years.
James Hutton : A Scottish geologist whose work established the importance of slow processes in shaping Earth. His observations of erosion and rock formation implied immense stretches of time.
Evolution : The change in heritable characteristics of populations across generations. Geological duration allows small biological changes to accumulate into major diversity.
Stratigraphy : The study of rock layers and their relationships in space and time. Layer order provides a relative chronology where direct dates are unavailable.
Rock cycle : The set of processes that form, alter, and recycle igneous, sedimentary, and metamorphic rocks. It explains how Earth's materials are continually transformed across geological time.
Charles Lyell : A British geologist who argued that geological features arose through processes still operating today. His influential account made gradual change central to nineteenth-century geology.
Paleontology : The scientific study of ancient life through fossils and other evidence. It reconstructs the changing history of organisms across geological time.
Radiometric dating : A method for determining ages by measuring radioactive decay in materials. Radioactive clocks assign numerical ages to ancient rocks and minerals.
Erosion : The removal and transport of rock and soil by water, wind, ice, or gravity. Erosion can slowly reshape landscapes while exposing records of older events.
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