tarseep

Tarseep is a term that is commonly written as tar seep or asphalt seep, referring to a natural surface expression of crude oil or heavy bitumen that appears as pools or oozing slicks on the ground. The combined form tarseep is less standard but may appear in some sources as an informal variant.

Tar seeps form when subsurface hydrocarbons migrate through porous rocks and encounter impermeable layers that trap them near the surface. The liquids and semi-solid bitumen rise along faults or fractures, often weathering into viscous pools of tar. Over time, lighter components may evaporate or degrade, leaving a surface deposit rich in heavy hydrocarbons and oxidized compounds.

Geographically, tar seeps occur in many regions with sedimentary basins. Famous examples include the La Brea Tar Pits in Los Angeles, which have yielded a wealth of Pleistocene fossils, and Pitch Lake in La Brea, Trinidad, the largest known natural deposit of asphalt. Such seeps are of interest to geologists for understanding hydrocarbon migration and to paleontologists for preserving ancient remains that became trapped in sticky tar.

Ecology and human use of tar seeps vary by location. Some seeps host specialized microbial and plant communities adapted to hydrocarbon-rich soils, while others are primarily studied as natural laboratories for petroleum system analysis. Historically, tar has been collected for waterproofing and construction in some regions; today, environmental monitoring and paleontological research are common activities associated with tar seeps.