Changes

:::Updip tar seal created by bacteria degradation of the hydrocarbons, preferentially removing the lighter fractions.

:::Updip tar seal created by bacteria degradation of the hydrocarbons, preferentially removing the lighter fractions.

::'''Subclass:''' Disseminated

::'''Subclass:''' Disseminated

::Tar or asphalt fills the pores of shales, sands, or carbonates. These traps are often called tar sands, oil shales, bituminous sandstones, or bituminous limestones.

::Tar or asphalt fills the pores of shales, sands, or carbonates. These traps are often called [[tar sands]], oil shales, bituminous sandstones, or bituminous limestones.

::'''Subclass:''' Veins

::'''Subclass:''' Veins

::The solid, essentially infusible form of petroleum is called pyrobitumen. It occurs in veins [[length::1 mm]] to [[length::8 m]] across and appears to have been injected or is a dead seepage.

::The solid, essentially infusible form of petroleum is called pyrobitumen. It occurs in veins [[length::1 mm]] to [[length::8 m]] across and appears to have been injected or is a dead seepage.