What did Earth look like in the Carboniferous? (358.86–298.9 Ma)

Key events of this period

• Pangaea Assembly

  335 Ma

  Pangaea assembled through continental collisions over tens of millions of years, raising mountain belts along the joins. The 335-million-year marker represents this process; by roughly 300 million years ago, present-day North America, Africa, South America and Europe were connected.

  References: What was Pangea? — U.S. Geological Survey · Gondwanaland from 650–500 Ma assembly through 320 Ma merger in Pangea to 185–100 Ma breakup

• Wetland forests that became coal

  320 Ma

  Around 320 million years ago, tropical wetland forests, including giant lycopsids, accumulated plant remains as peat. Wet climates and subsiding basins favoured burial, eventually turning some deposits into coal. Fossil and evolutionary evidence challenges the claim that coal accumulated because fungi could not yet decompose wood.

  References: Nelsen et al.: Delayed fungal evolution did not cause the Paleozoic peak in coal production

• Early amniotes

  312 Ma

  By 312 million years ago, amniotes already existed; protective embryonic membranes were a key adaptation for reproduction away from water. A 2025 study interpreted Australian tracks around 359–354 million years old as amniote footprints, suggesting a much earlier history. This is evidence inferred from tracks, not fossil eggs.

  References: Long et al.: Earliest amniote tracks recalibrate the timeline of tetrapod evolution

• Carboniferous rainforest retreat

  307 Ma

  Around 307–305 million years ago, drier conditions reorganized tropical wetland forests in today’s Europe and North America. Amphibian habitats shrank, while fossil analyses suggest some surviving tetrapods spread more widely. Coal forests persisted elsewhere, including China; this was not a simultaneous disappearance of all Earth’s forests.

  References: Dunne et al.: Diversity change during the rise of tetrapods and the impact of the Carboniferous rainforest collapse · Fang et al.: Synchronizing climate-carbon cycle heartbeats in the Phanerozoic vegetated icehouses · Dunne et al.: Mechanistic neutral models show that sampling biases drive the apparent explosion of early tetrapod diversity

• Late Paleozoic Ice Age

  305 Ma

  During the Carboniferous–Permian Late Paleozoic Ice Age, ice sheets advanced and retreated across southern Gondwana. Multiple ice centres and intervals of retreat replaced the idea of one continuous ice blanket; carbon dioxide was an important control.

  References: The Late Paleozoic Ice Age: An Evolving Paradigm