Chapter 8: 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 early drift-phase paleogeography of middle to late 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. Emphasis is on the Kimmeridgian and Tithonian because of their economic importance. The southern Mexico Maya Block and Guatemala Rubelsanto trough are most likely related to the Triassic back-arc spreading of central Mexico and the back-arc basin of the Magdalena rift, which includes the Cocinas trough of the Guajira. The Yucatan rotation during the early Jurassic orients the Akal horst of Reforma and aligns it with the Cocinas trough, causing the two to have similar paleogeographies. Of particular significance is the presence of Kimmeridgian ammonites in the Cocinas Group of the Guajira and the potential relationship of the Cocinas with the Kimmeridgian of southern Mexico. The role played by the Chiapas Block is discussed, and this block is considered to have been a later addition to the Maya Block. It is most likely post-Kimmeridgian and does not appear to have played a role during the late-Jurassic depositional setting. The proposed model allows for Kimmeridgian exploration targets to extend beneath the Artesa–Mundo Nuevo platform (southern Reforma trend), which may be present under more favorable marine conditions in the projected Cocinas trough of the western part of the Gulf of Venezuela.