GEO GIRL Courses

How We Know What Happened in Earth's Past - Like Ancient Climate, Geology, and Extinctions

Learn how physical, chemical, and biological traces preserved in rocks reveal ancient climates and other events in Earth's history.

• YouTube
• 51 minutes
• Self-Paced
• Free Video

Why Microbes Are Necessary for All Life on Earth - Geo Girl

Microbes keep essential elements usable by driving the cycles that connect life, water, air, and Earth’s crust.

• YouTube
• 27 minutes
• Self-Paced
• Free Video

Biogeochemical Cycles - Weathering, C Burial, Anoxia, Ocean Chemistry, and More

Explains how tectonics and biological activity reshape ocean chemistry, linking anoxic events, mineral formation, and long-term climate.

• YouTube
• 25 minutes
• Self-Paced
• Free Video

Carbon Cycle - Greenhouse Gases, Photosynthesis, Respiration, C Burial, and More

Trace how carbon moves through Earth’s reservoirs, and how carbon isotopes reveal ancient burial, early life, and fossil fuel influence on today’s atmosphere.

• YouTube
• 21 minutes
• Self-Paced
• Free Video

How and Why Earth Went From Purple to Green - Twice

Examines evidence for two possible Purple Earth periods and the microbial pigments that may have turned Earth from purple to green.

• YouTube
• 21 minutes
• Self-Paced
• Free Video

Times Plate Tectonics Caused Global Climate Change - GEO GIRL

Trace five supercontinent breakups, shifts, and collisions that altered Earth’s climate across deep time.

• YouTube
• 22 minutes
• Self-Paced
• Free Video

Mass Extinction Causes Nobody Talks About - GEO GIRL

How lesser-known atmospheric, chemical, biological, and astronomical triggers contributed to mass extinctions.

• YouTube
• 24 minutes
• Self-Paced
• Free Video

All the Types of Sand and Why There's So Many Colors - Geo Girl

Explore how erosion, rock composition, and organisms create sands ranging from quartz and black sand to ooids, gypsum, olivine, and parrotfish poop.

• YouTube
• 24 minutes
• Self-Paced
• Free Video

The "Boring Billion"- What Really Happened 1.8 to 0.8 Billion Years Ago?

An exploration of why Earth's “Boring Billion” stayed environmentally stable for a billion years—and how oxygen, ocean chemistry, and tectonics shaped early complex life.

• YouTube
• 28 minutes
• Self-Paced
• Free Video

Everything You Could Ever Want to Know About Ice - GEO GIRL

Explore why water ice floats, how its 19+ crystal phases differ, and how snow, hail, sleet, and other atmospheric ice forms.

• YouTube
• 25 minutes
• Self-Paced
• Free Video

The Controversial Role of Oxygen in Animal Evolution and Diversification

Examines whether rising oxygen caused animal evolution, weighing oxygen against temperature, productivity, nutrients, and animal-driven changes.

• YouTube
• 22 minutes
• Self-Paced
• Free Video

How Earth’s Crust Formed and Difference Between Tectonic Plates and Crust - GEO GIRL

Explains how Earth’s crust formed and differentiated into oceanic and continental crust, and why crust is not the same as a tectonic plate.

• YouTube
• 20 minutes
• Self-Paced
• Free Video

Difference Between Stable and Radioactive Isotopes and Their Applications

Compare stable and radioactive isotopes and see how isotope ratios reveal radiometric ages, ancient climates, early life, emissions, and geological conditions.

• YouTube
• 28 minutes
• Self-Paced
• Free Video

Types of Clays - Composition, Structure, and Bonding of Clay Minerals

Learn how weathering controls clay composition and structure, from phyllosilicate layers to iron and manganese oxides, including clay minerals found on Mars.

• YouTube
• 26 minutes
• Self-Paced
• Free Video

What Is Carbon Sequestration, Why Is It Important, and How Does It Work? - GEO GIRL

Explains how regenerative soils and mineral weathering remove and store atmospheric carbon over different timescales.

• YouTube
• 20 minutes
• Self-Paced
• Free Video