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Paleontology in Arkansas refers to paleontological research occurring within or conducted by people from the U.S. state of Arkansas. The fossil record of Arkansas spans from the Ordovician to the Eocene. [1] Nearly all of the state's fossils have come from ancient invertebrate life. [1] During the early Paleozoic, much
Oil exploration began in earnest in 1916 with an unsuccessful well east of El Dorado, in Union County (which at the time was known as Urbana County). A week after Samuel S. Hunter found modest amounts of oil in the Hunter No. 1 well near Stephens, Arkansas, the Constantin Oil and Refining Company found large amounts of oil and natural gas. Soon ...
Reservoir rocks may be developed in pre-rift, syn-rift and post-rift sequences. Effective regional seals may be present within the post-rift sequence if mudstones or evaporites are deposited. Just over half of estimated oil reserves are found associated with rifts containing marine syn-rift and post-rift sequences, just under a quarter in rifts ...
The highest natural point is Raspberry Mountain at 2,358 feet (719 m). The headwaters of multiple rivers are found in this area, including the Caddo, Cossatot, and Little Missouri rivers. The Cross Mountains are located in Polk and Sevier counties, Arkansas and McCurtain County, Oklahoma. The highest natural point is Whiskey Peak at 1,670 feet ...
Lake-filled half-graben showing sedimentation dominantly from the 'hinge' margin. Four zones of sedimentation can be defined in a half-graben. The first is "escarpment margin" sedimentation, found along the major border faults bounding the half graben, where the deepest part of the basin meets the highest rift-shoulder mountains. [6]
Wood grain is the longitudinal arrangement of wood fibers [1] or the pattern resulting from such an arrangement. [2] R. Bruce Hoadley wrote that grain is a "confusingly versatile term" with numerous different uses, including the direction of the wood cells (e.g., straight grain, spiral grain), surface appearance or figure, growth-ring placement (e.g., vertical grain), plane of the cut (e.g ...
They could once be found all throughout Arkansas, but had more-or-less vanished by 1920, the Commission said, but there have been 23 confirmed sightings in the state beginning in 2010.
Riftsawn wood has every board cut along a radius of the original log, so each board has a perpendicular grain, with the growth rings oriented at right angles to the surface of the board. However, since this produces a great deal of waste (in the form of wedge-shaped scraps from between the boards) rift-sawing is very seldom used.