PRELIMINARY PALAEOMAGNETIC STUDY OF LOWER TERTIARY VOLCANIC ROCKS FROM MORELOS AND GUERRERO STATES

摘要: Mean palaeomagnetic directions and pole positions deriven from seven lower Tertiary volcanic units exposed in central-southern Mexico after alternating field thermal demagnetization diverge corresponding data of northern Mexico. The studied unists are two lavas the Palaeocene-Eocene Balsas Formation, tuffs Riolita Tilzapotla (K-Ar date 49 ± 3 m.y.) an andesitic lava Miocene (?) volcanics. results could be explained terms relative counterclockwise tectonic rotations sampling areas, possibly associated with regional compression shear acting on blocks cut by large lateral strike-dip faults. However, we feel that more required to support this interpretation before a model can put forth.