Alfred Wegener, a German meteorologist and geophysicist, first proposed the theory of Continental Drift in the early 20th century. He suggested that the Earth’s continents were not fixed but had slowly moved across the planet’s surface over geologic time. This theory introduced Pangaea, a single supercontinent that existed approximately 335 to 175 million years ago before splitting into the landmasses we know today. One of the most compelling lines of proof for Wegener’s hypothesis came from the distribution of ancient coal deposits. The current locations of these fossil fuel reserves only make sense if the continents were once positioned differently.
Climatic Requirements for Coal Formation
The formation of coal requires specific environmental conditions, typically found only in low-latitude regions today. Most significant coal reserves originated during the Carboniferous Period (359 to 299 million years ago), often called the “Coal Age.” This era was characterized by vast, low-lying coastal swamps and delta plains.
Abundant plant material, such as giant ferns, needed preservation to prevent decay. This occurred when dead vegetation fell into waterlogged, anaerobic environments like peat mires. The warm, humid climate near the ancient equator supported lush, rapid plant growth. Over millions of years, burial by sediments subjected these thick peat layers to immense heat and pressure, a process called coalification, which transformed the organic matter into coal.
The Paradox of Polar Coal Deposits
Given the tropical conditions required for coal formation, the current location of many massive coal seams presents a geological puzzle. Major coal deposits are now found in frigid, high-latitude environments, incompatible with ancient swamp conditions. This includes extensive reserves in Siberia, the Canadian Arctic, Greenland, and Antarctica.
For instance, coal seams up to six meters thick exist within the Transantarctic Mountains. This indicates that Antarctica, the most ice-covered continent, must have once hosted vast, tropical or subtropical forests. Similarly, coal found in Svalbard, a Norwegian archipelago in the Arctic Ocean, points to a past climate dramatically different from its present subpolar environment. Finding evidence of lush, equatorial life in the world’s coldest regions constituted a major paradox for geologists who believed the continents were fixed.
Reconstructing Pangaea to Explain Coal Locations
The solution to this climatic paradox lay in Continental Drift, allowing Wegener to synthesize the paleoclimatic data. He proposed that the landmasses had moved, meaning a continent’s current position does not reflect its historical climate zone. By reassembling the continents into Pangaea, the ancient locations of these coal deposits aligned in a coherent pattern.
When the continents are fitted together, the seemingly misplaced coal deposits from high-latitude regions like Antarctica and North America fall neatly within Pangaea’s reconstructed equatorial belt. This placement put the landmasses in the required tropical zone approximately 300 million years ago, allowing for the formation of vast swamp forests. The existence of these coal beds in their current, cold locations thus became powerful evidence that the continents had drifted from their tropical origins to their present positions. The distribution of coal serves as a paleoclimatic fingerprint, demonstrating the extent of continental movement over geologic time.