Title: Structural analysis of Quachita Mountains in Arkansas
Abstract: Existing mapping, reconnaissance field work, and the construction of three deep, balanced and semi-balanced cross-sections through the Arkansas Quachitas demonstrate that: (1) Ouachita folds extend well north of the Arkansas River, and probably form above bedding-plane decollements, some of them blind; (2) angular anticlines with steep forelimbs and long, gentle back limbs dominate the Ouachita foreland; these folds have structural relief of 1 to 3 km; many of them are cut by crestal faults with displacements much smaller than the height of the folds; (3) moderate north dip of cleavage and bedding dominates the Stanley Formation outcrop belt north of the Benton uplift; (4) steep south dips and multiple imbricate thrust faults dominate the Athens Plateau. The cross-sections suggest that asymmetric frontal folds may be fault-propagation folds, or may form over backthrusts (triangle zones), or over basement-cutting flexural normal faults. Common north-side-up faults on the north side of the Benton uplift, as well as the possible occurrence of triangle zones beneath the frontal folds, suggest that back-thrusting may be quite important in the Ouachitas. The Benton Anticlinorium is probably cored by North American basement; it is probably allochthonous and rides on a thrust that the authors identify largely with themore » surface Y City fault. Although some Ouachita sedimentary rocks may have been deposited on transitional or oceanic crust, it is unlikely that a suture is exposed in the Ouachitas. Ouachita structures (not lithologies) are similar to Appalachian ones.« less
Publication Year: 1985
Publication Date: 1985-01-01
Language: en
Type: article
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