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Mesozoic rocks of the Gulf were deposited on a wide coastal plain which was punctuated transversely by major positive and negative warpings. Two of the positive elements (Sabine and Monroe uplifts) underlie giant hydrocarbon accumulations. The Wiggins arch is notable because, although the flanks are productive, the crestal area is barren. This condition has led to a paucity of well control, especially deep well control. Only three wells on the arch have penetrated the entire sedimentary sequence (20,000 ft, 6,100 m) and reached basement rock (2 granite, 1 metamorphic) dated at 300 ± m.y. These three wells are reported to have a normal stratigraphic sequence except that the Jurassic Haynesville Formation lies on the basement, and the Buckner, Smackover, Norphlet, and ouann are missing. Careful analysis of these wells indicates the lower part of the reported "Haynesville" is time-correlative with the Smackover. Thus, the Smackover is not missing, but is represented by a Haynesville-like facies deposited on a block of granitic basement. This block must have been barely emergent and led to a complex set of cays during Smackover deposition. Careful analysis of seismic records indicates the proposed cays are surrounded by areas of very different reflective character. These reflections may indicate the presence of high-energy Smackover carbonate and Norphlet sand that is missing from the wells.
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