Surendra Pal

Magma characterization of the Mexican volcanic belt (Mexico)

Over 330 bulk chemical analyses of rocks (Oligocene or Miocene to Recent) from the Mexican Volcanic Belt (MVB) have been compiled. These analyses all together represent a calc-alkaline sequence of continental margin type. The North-Eastern part of the Belt seems to overlap with another volcanic province, namely. Eastern Cordillera in which magmas are mostly of alkaline sequence. A model involving fractional crystallization as the principal mechanism is proposed for magma genesis in the MVB.

Rare-earth elements in basalt samples, Gulf of California

Abstract Results are given of chemical analyses and rare-earth elements of glass rims, crystalline interior (core) and altered exterior (margin) of three pillow basalts from the mouth of the Gulf of California. A notable alteration effect of low-temperature weathering seems to be a loss of rare-earth elements from basalt.

Paleomagnetic data from tertiary igneous rocks, northeast Jalisco, Mexico

Abstract New paleomagnetic measurements have been made on Tertiary volcanic rocks from northeast Jalisco, Mexico (20.7°N, 102.3°W). The pole position obtained from this study (68°N, 181°E) is consistent with two other Oligocene poles from Mexico. Mexican poles form a coherent group which differs from poles of similar ages from North America. This suggests a possible tectonic rotation of the sampling sites of Mexico with respect to “stable” North America.