CONTRIBUTION OF CLAY MINERAL SUCCESSIONS FOR RECONSTRUCTING THE PALEOGEOGRAPHIC AND DIAGENETIC EVOLUTION OF UPPER MESOZOIC SEDIMENTS OF GUATEMALA

Numerical data of clay mineral analyses of Upper Jurassic to Cretaceou s formations from both Maya and Chortis blocks, located north and sout h of Guatemala respectively, were replaced in the presently-known pala eogeographic, stratigraphic and lithologic framework, which allowed to distinguish the respective influence of geodynamic and diagenetic con straints. The identified diagenetic effects are frequently recognized and resulted from depth of burial, tectonic features and ophiolite emp lacement. Such effects nevertheless obliterate partly only the geodyna mic messages expressed by clay mineral associations on the detrital so urces, on weathering and drainage conditions controlled by warm humid climate, on the occurrence of seaways between the different sedimentar y basins, and on tectonic events. The diagenetic effects appear to pre dominate in the southeastern Guatemala and to the south of the fault s ystem separating the Maya and the Chortis blocks. The palaeogeographic conditions seem to have especially varied to the west of the northern Maya block during late Mesozoic times.