Lecture 2: Historical Geology and Geologic Time

Explores the concept of the early geologists, history of geology, and deep time.

Neptunism

The geological theory that all rocks originated from sedimented deposits of minerals in the Earth’s oceans.

Plutonism

The geological theory that rocks, especially igneous rocks, form from the cooling and solidification of molten magma beneath the Earth's surface.

Uniformitarianism

The principle that the same natural laws and processes that operate in the universe now have always operated in the past, suggesting that current geological processes can interpret past events.

Actualism

The concept that natural laws and processes observed today have always operated throughout Earth's history, recognizing variations in rates and intensities over time.

Charles Lyell

Geologist who formalized the concept of uniformitarianism and emphasized the uniformity of natural processes through time.

Nicholas Steno

The Father of Stratigraphy, who proposed principles such as superposition and original horizontality to understand rock layers.

William Smith

Creator of the first geological map, using fossils to determine the correct positioning of rock layers.

Eons

The largest divisions of geological time, spanning billions of years.

Hadean

The eon marking the beginning of Earth’s formation.

Archean

The eon characterized by the beginning of plate tectonics and the earliest evidence of life.

Protozoic

The eon during which the atmosphere and biosphere evolved, including the formation of banded iron formations (BIFS).

Phanerozoic

The eon when complex life began to emerge.

Paleozoic

The era within the Phanerozoic characterized by trilobites and the supercontinent Pangea.

Mesozoic

The era known for dinosaurs and significant geological events like the western orogeny.

Cenozoic

The current era of geological time, encompassing the present day.

Krakatoa

A volcanic eruption at a convergent plate boundary that resulted in a tsunami.

Mt

A volcanic eruption that buried the city of Pompeii due to the convergence of the African and Eurasian plates.

Santorini

A volcanic event that was three to four times the magnitude of Krakatoa, likely ending the Minoan civilization.

East African Rift Valley

A geological event where a continent is splitting apart, preserving ancient footprints.

Australopithecus Tracks

Fossilized tracks that provide insight into early human evolution and bipedalism.

San Francisco Earthquake of 1906

A significant geological event in U.S. history.

Climate Change

The transition of the Middle East from a humid region to a desert after 10,000 years ago, influenced by Ice Age changes.

Sea Level Rise

The progressive increase in sea level due to melting glaciers, with potential rises of 50 meters if major ice sheets melt.

Rapid Geologic Processes

The historical view that the Earth changes catastrophically and rapidly, prevalent until the 1850s.

Deep Time

The concept introduced by James Hutton, suggesting that geological processes and time explain the Earth's history.