Geology: Fossils and Stratigraphy Principles

Fossils that existed for a short period of time over a wide geographic range, making them valuable for correlating rock layers across different locations.

The study of fossils, including their identification, classification, and distribution, for establishing the relative ages of rock layers.

The process of establishing the sequence of events in a geological history by examining rock layers and their relationships to each other.

The principle that states that rock layers are originally deposited horizontally and may be tilted or folded later.

The principle that states that rock layers are deposited in a continuous sequence, extending laterally unless interrupted by a barrier.

The principle that states that in undisturbed rock sequences, older layers are found below younger layers.

The principle that states that a rock fragment included within another rock must be older than the rock containing it.

The principle that states that a geologic feature that cuts across another feature is younger than the feature it cuts.

Exceptional geological formations preserving diverse organisms, including soft-bodied ones, offering insights into life's history.

A Cambrian formation in Canada abundant with fossilized creatures, including the flatworm Ottoia.

A Lower Cambrian site in China featuring one of the earliest known vertebrates, Haikouichthys.

The four fundamental elements (carbon, hydrogen, oxygen, and nitrogen) essential for life.

A hypothesis proposing Earth's early atmosphere lacked free oxygen, allowing organic molecules to form from inorganic ones.

An experiment simulating early Earth conditions, producing amino acids from inorganic molecules.

A process where simple organic molecules like amino acids combine to form larger polymers.

Simple, single-celled organisms believed to be the earliest life forms.

The study of fossils to understand Earth's history and the evolution of life.

Fossils that preserve the shape of the organism's body, such as bones, teeth, shells.

Fossils that preserve traces of an organism's activity, such as footprints, burrows, or nests.

A process where organic material is compressed and flattened, leaving behind a thin film of carbon that preserves the shape of the organism.

A process where organisms are trapped in hardened tree sap, preserving them in remarkable detail.

A process where organisms are trapped in sticky tar seeps, preserving them in intricate detail.

Environments that offer exceptional preservation conditions, leading to fossils with intricate details of soft tissues.

The oldest eon in Earth's history, starting with the planet's formation, with no surviving rock record. Earth was molten then.

The boundary between the Hadean and Archean eons, marked by the oldest rocks found in the geological record.

This eon holds the oldest rocks found on Earth. While initially thought to lack fossils, later discoveries showed the oldest fossils within its layers.

The boundary between the Archean and Proterozoic eons, defined by the appearance of distinctive rock formations called banded iron formations.

The eon that was initially defined by the oldest fossils found, thought to be small and microscopic. Later, larger fossils were discovered in its upper layers.

The boundary between the Proterozoic and Phanerozoic eons, marked by the 'Cambrian Explosion,' a rapid increase in diversity and complexity of life forms.

The youngest eon, known for its large, easily recognizable fossils found in many sedimentary rocks.

The oldest era of the Phanerozoic eon, containing fossils with some resemblance to modern life forms, including Cambrian, Ordovician, Silurian, and Devonian periods.

The era known for fossils resembling more modern forms, subdivided into Triassic, Jurassic, and Cretaceous periods. Marked by the rise of dinosaurs and other iconic creatures.

A group of vertebrates lacking jaws, with skeletons made of cartilage, no fins or teeth, and simpler digestive and respiratory systems compared to later vertebrates.

Early jawless fish, fossils found in Lower Cambrian deposits in China.

An extinct group of jawless fish that lived during the Ordovician period in South America.

A group of vertebrates that adapted to life in the water, with a distinct jaw structure, a more complex digestive system and respiratory system, and a bony skeleton in most cases.

An extinct fish with a powerful bite. Its fossils are found primarily in the Upper Devonian rocks of Ohio and Europe.

An extinct group of marine fish that lived during the Late Cretaceous period.

The first vertebrates to emerge from the water and adapt to land.

Reptiles evolved from amphibian ancestors and were better adapted to a fully terrestrial lifestyle.

A type of fossilization where the original material of the fossil is replaced by a new mineral, often resulting in a detailed preservation of internal structures.

This occurs when minerals dissolved in fluids precipitate within the empty space left by a dissolved fossil, creating a new mineral replica of the original organism.

A fossilization process where pyrite, a mineral composed of iron sulfide, replaces the original organic material, often preserving details of soft tissues.

The complete replacement of a fossil's chemical and mineral composition by highly reactive fluids, often producing detailed preservation of fine structures.

A rare preservation method where a dead body is preserved in permafrost, with potentially intact organs and stomach contents.

A fossilization process where a dead body dries out rapidly in desert environments, preventing decay and preserving the external form.