University of Arkansas at Little Rock

On a recent Wednesday afternoon in October, Dr. Beth McMillan’s Sedimentology class visited world class exposures of the 300 million year old Jackfork Formation in the Ouachita Mountains of Arkansas. Many of the major oil and gas companies send their geologists to study these rocks because they were deposited in an environment very similar to that in which oil and gas producing sediments in the Gulf of Mexico are currently being deposited. Being able to view lateral and vertical relationships in ancient rock layers exposed on land helps petroleum geologist to interpret the geometry of oil and gas reservoirs in the subsurface.