Severed Mineral Estate
A tract where the minerals have been legally separated from the surface, so different parties own what's above and below ground.
A severed mineral estate exists when the minerals under a tract have been legally separated from the surface, so one party owns the surface and another owns the minerals. The split, or severance, happens through a deed that either conveys the minerals away or reserves them when the surface is sold.
Once severed, the two estates travel independently through sales, inheritance, and leasing. A buyer can own 100% of the minerals under land they have never set foot on. In most states the mineral estate is the dominant estate, giving the mineral owner reasonable surface access to develop — which is where conflicts with surface rights arise.
Severance is the reason title work runs deep in oil and gas country. See the title search guide and inherited mineral rights for how these chains form.