Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Along the NE flank of Cuba, parts the Bahamian carbonate platform are exposed, while in the central part of the island a Cretaceous volcanic arc sequence is present. Rudist assemblages are found in both of these major tectonic settings… in order to continue, download the full paper in PDF.

In the shallow-water Cretaceous deposits of Cuba, Aptian to Maastrichtian rudist faunas have been found within two main general tectonic setting: the Bahamian carbonate platform and the Cretaceous volcanic arc, in limestone lenses and small carbonate platforms… in order to continue, download the full paper in PDF.

A small assemblage of rudists was described in the 1930´s from central Guatemala by MacGillavry and Mullerried… in order to continue, download the full paper in PDF.

In the past four years, we have been studying the geology and petrology of the Durango volcanic field (DVF) (Aranda-Gómez et al., 1988, 1989, 1991; Smith et al., 1989; Pier et al., 1991). We paid special attention to the La Breña-El Jagüey volcanic complex (LBEJVC), because it is one of the few places in the DVF in which the detailed evolution of a volcanic center can be unraveled, and where a collection of volcanic rocks, whose relative ages could be inferred, can be obtained. According to our interpretation, the LBEJVC consists of two intersecting maars-La Breña (LB) and El Jagüey (EJ)-at least two pre-maar scoria cones and associated lavas, and a series of nested post-maar lava and scoria cones that erupted within LB and flooded its floor with lava (Figures 1 and 2, a). A completely different model for the evolution of LBEJVC was recently proposed by Swanson (1989). In this communication, we will briefly summarize the two models and then review key field and laboratory observations that, we believe, support our model and contradict the model of Swanson (1989). Our field observations led us to propose a model for the geological evolution of the complex (Aranda-Gómez et al., 1988, in press), which forms the basis of our petrogenetic model (Pier et al., 1991). In order to continue, download the full article in PDF

The major point of the paper under discussion (Swanson, 1989) is that the El Jagüey-La Breña complex, located in Durango's Guadiana valley (Figure 1), is a previously unrecognized type of maar volcano, in which a caldera (La Breña) formed following eruption of supporting material through an adjacent maar (El Jagüey). The paper proposed a simple developmental history (Figure 2), consistent with the geology and location of the volcanic complex. The complex started as a scoria cone, like 100 others in the valley; it evolved into a breach scoria cone, as most scoria cones do; then water encroachment briefly and dramatically converted the eruption style from magmatic to phreatomagmatic, creating El Jagüey maar and the adjoining La Breña caldera. The objections presented by Aranda-Gómez and coworkers (1990), termed conclusive and supportive, can be categorized as: (1) questioning the one-maar interpretation; (2) questioning details of the developmental model for the El Jagüey-La Breña complex; or as (3) supportive of their own two-maar interpretation. I welcome the opportunity to answer to their objections and elaborate on this distinctive type of maar volcano. In order to continue, download the full article in PDF

The fragipan consists of very compact horizons with high-bulk density and some brittleness. Its supposed origin could be igneous or sedimentary. In Mexico, it is known as tepetate, a Náhuatl word that means different compact or cemented materials… in order to continue, download the full paper in PDF.

The Guerrero terrane of western Mexico includes arc sequences, particularly the Mexican Late Jurassic-Early Cretaceous Alisitos-Teloloapan arc… in order to continue, download the full paper in PDF

The study area lies the west-central part of Mexico, at the intersection of the Sierra Madre Occidental and the Neovolcanic Plateau… in order to continue, download the full paper in PDF.

En la región de la presa de Santa Rosa existen evidencias de una zona de falla de desplazamiento lateral izquierdo, cuya dirección es N30°W… Para continuar, descargue el artículo completo en PDF.

In the Central Mexico Plateau, there are several jasperoids with a general trend from N to N 20° E, spatially associated to Tertiary intrusives, which were controlled by shear fractures caused by Laramide compression… in order to continue, download the full paper in PDF.