Geology Study Guide #2

Continental Drift

The theory that states that the continents have moved over time.

Alfred Wegener

A scientist who provided evidence for continental drift.

Permian-Triassic Fossils

Fossils found across southern continents that suggest they were once joined.

Glacial Deposits

Deposits left behind by glaciers that indicate past ice ages.

Divergent Boundary

A boundary where tectonic plates are pulling apart.

Transform Boundary

A boundary where tectonic plates slide past each other.

Convergent Boundary

A boundary where tectonic plates are pushed together.

Moho

The boundary between the crust and upper mantle.

Lithosphere

The rigid layer formed by the crust and upper mantle.

Asthenosphere

The partially molten layer below the lithosphere.

Strike and Dip

Measurements used to describe the orientation of rock layers.

Syncline

A fold in rock layers where the youngest rock is in the middle.

Anticline

A fold in rock layers where the oldest rock is in the middle.

Overturned Folds

Folds where the axial plane is inclined.

Water Cycle

The continuous movement of water on, above, and below the surface of the Earth.

Evaporation

The process of water turning into water vapor and entering the atmosphere.

Evapotranspiration

The process of water vapor being lost to the air by plants.

Desertification

The drying up of an area due to the lack of plants.

Carbon Cycle

The movement of carbon between the atmosphere, oceans, and land.

Volcanic Outgassing

The release of carbon dioxide and other gases from volcanoes.

Biological Carbon

The carbon that enters biological systems through photosynthesis.

Fossil Fuels

Ancient organic materials that can be burned for energy.

Eutrophication

The excessive growth of algae in bodies of water due to excess nutrients.

Global Air Circulation

The movement of air around the Earth due to temperature differences.

Greenhouse Gases

Gases that absorb and re-radiate heat, contributing to the greenhouse effect.

Albedo

The reflectiveness of a surface.

Proxy Data

Indirect evidence used to infer past climate conditions.

Radiometric Dating

The method of dating rocks and minerals using radioactive isotopes.

Blocking Temperature

The temperature below which a mineral can retain daughter isotopes.

Paleogeography

The study of the ancient geography of the Earth.

Paleoclimatology

The study of past climates and how they have influenced the deposition of rocks.

Evaporite

A type of rock that forms in arid climatic conditions.

Coal

A type of rock that forms in swampy areas with high precipitation.

Carbonates

Rocks that primarily form in warm water environments.

Paleogeography

Our knowledge of the past geographic arrangement of continents and land masses.

Cratons

Large, under-formed portions of continents that primarily formed during the Precambrian.

Precambrian Shield

The exposed portion of a craton, such as the Canadian Shield in northeastern Canada.

Oldest Region of Crust

The Canadian Shield, which is the oldest known region of crust on Earth.

Continental Accretion

The process by which deep water sediments are added to a continent.

Prokaryote

A type of organism that is smaller and simpler than eukaryotes, lacking organelles.

Eukaryote

A type of organism that is larger and more complex than prokaryotes, with organelles and a nucleus.

Origin of Life

The question of where and when life first originated on Earth.

Multicellular Algae

Algae that evolved multicellularity around 580 million years ago.

Ediacaran Biota

A group of organisms that lived during the Ediacaran Period, characterized by their lack of modern phyla characteristics.

Cambrian Explosion

The rapid appearance and diversification of many modern phyla with skeletons during the Cambrian Period.

Laurentia

The name for the North American continent during the Cambrian Period.

Sea Level in the Cambrian Period

Sea level started low and rose throughout the period, eventually drowning most of Laurentia.

Mineralized Skeletons

Structures made of minerals, such as calcite, apatite, and silica, that provide structure and protection to organisms.

Trace Fossils

Fossilized evidence of animal activity, such as burrows or tracks.

Ordovician Period

A period of geologic time characterized by tectonic changes to Laurentia and the presence of prominent fauna such as graptolites, corals, and cephalopods.