Hiililähteitä

Hiililähteitä, often translated as "coal springs" or "coal seeps," are geological formations where liquid or gaseous hydrocarbons, primarily coalbed methane and oil, naturally escape from underground coal deposits to the surface. These occurrences are less common than oil or gas seeps from other rock types due to the porous nature of coal which tends to retain hydrocarbons more effectively. However, when pressure or geological faulting allows, these resources can migrate upwards.

The formation of hiililähteitä is linked to the processes of coalification, where organic matter is transformed into coal under heat and pressure over millions of years. During this process, volatile compounds, including methane, are generated and trapped within the coal seams. If these seams are fractured or intersected by permeable layers, the trapped gases and any associated liquids can find a pathway to the surface.

Historically, hiililähteitä were sometimes observed by indigenous peoples and early explorers, and in some instances, their presence indicated accessible energy resources. In modern times, their study is of interest to geologists researching hydrocarbon migration, coalbed methane potential, and the natural release of greenhouse gases. While not typically exploited as major commercial sources, they serve as natural indicators of subsurface hydrocarbon activity. The composition of gases and liquids emitted can vary depending on the coal type and the geological conditions of the site.