. Collected reprints / Atlantic Oceanographic and Meteorological Laboratories [and] Pacific Oceanographic Laboratories. Oceanography 295 0 KM 50 100 150 200 250 300 350 ,—,_, ,, , ,, , i,—<—^—^ SEAWARD. VERTICAL EXAGGERATION ABOUT 25:1 Fig. 6. Model to interpret the development of the marked change in inclination of the Paleozoic crystalline basement surface observed beneath the Hatteras coastal plain—con- tinental shelf (Fig. 3). A. A surface of erosion develops (on Paleozoic rocks) to form the original surface of the coastal plain—continental shelf. B. The surface of erosion
. Collected reprints / Atlantic Oceanographic and Meteorological Laboratories [and] Pacific Oceanographic Laboratories. Oceanography 295 0 KM 50 100 150 200 250 300 350 ,—,_, ,, , ,, , i,—<—^—^ SEAWARD. VERTICAL EXAGGERATION ABOUT 25:1 Fig. 6. Model to interpret the development of the marked change in inclination of the Paleozoic crystalline basement surface observed beneath the Hatteras coastal plain—con- tinental shelf (Fig. 3). A. A surface of erosion develops (on Paleozoic rocks) to form the original surface of the coastal plain—continental shelf. B. The surface of erosion tilts seaward by landward uplift and seaward subsidence about an axis perpendicular to the plane of the diagram (axis 1, Late Jurassic—Early Creta- ceous). Erosion occurs landward of axis 1 and sedimentary strata (Late Jurassic—Early Cretaceous) are deposited seaward of axis 1. C. The axis of seaward tilting shifts landward to axis 2 (post-Early Cretaceous) with a corresponding shift in the areas of erosion and deposition. The shift from axis 1 to axis 2 has resulted in a corresponding local epicontinental marine transgression. CONCLUSIONS The continental margins of southeastern North America and northwestern Africa were formerly conjugate, have rifted, and have drifted apart during the Mesozoic and Cenozoic as the intervening central North Atlantic ocean basin has opened and accreted by sea-floor spreading (Fig. 1). Development of the characteristic seaward thickening wedge of Mesozoic and Cenozoic sedimentary strata beneath the coastal plain—continental shelf of southeastern North America and northwestern Africa (Fig. 3) is con- trolled by seaward tilting of the original pre-Late Jurassic shelf surfaces by epeirogenic subsidence. Two categories of hypotheses attempt to explain the subsidence of rifted aseismic continental margins: 1068. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability
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