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Paleogeographic Constraints on Middle to Late Jurassic Tectonic Reconstruction of the Maya Block of Southern Mexico and Equivalent Strata of Northwestern South America

Abstract

The pre-rift reconstruction of Middle to Upper Jurassic Northwestern South America with rocks of equivalent age on the Maya block of southern Mexico remains problematic. Most published work has relied on paleomagnetic data rather than detailed correlations between sedimentary rocks of similar age or the orientations of major Mesozoic rifts. The focus of the present paper reviews the geologic impact of the various models discussed with reference to the observed geologic features in each of the principal terranes observed in the region with special emphasis in the Guajira and southern Mexico. Geologic evidence in the Mexican sector of the Gulf of Mexico inhibit rotation of Yucatan after the Callovian. The southern Mexico Jurassic Ixtapa graben and Rubelsanto Trough of Guatemala have an East West orientation as does the Cocinas graben in the Guajira. When rotated to their pre-rift position the grabens align up with the Machiques/Perija Trough and the Eastern Mexico Graben pattern. Of particular significance are the presence of Kimmeridgean ammonites reported by Renz (1959) in the Cocinas Group of the Guajira and its potential relationship with the Kimmeridgean of southern Mexico. The role played by the Chiapas Massif is discussed and considered to be a later addition to the Maya Block. It is most likely post Kimmeridgean and does not appear to have played a role during the late Jurassic depositional setting.