Sistema Regional de Información
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  The area devoted to Persian lemon cultivation in the Papaloapan Basin region, Oaxaca, increased by more than 86% in the last ten years while its participation in international markets increased. This fact, together with the favorable natural conditions of the region for the production of the crop, shows a potential for growth. The objective of the research was to evaluate the competitive performance of the producers of said region, as well as to calculate its price-cost competitiveness through the application of a survey. In the first case, we used the valuation of their positioning capacity in the market and the knowledge they have of it. For the calculation of price-cost competitiveness, the Policy Analysis Matrix was taken as the basis. The results show a low competitive performance due to the fact that less than half of the surveyed population performs technological development and human resource training activities that allow them to position themselves better in the market, in addition to a lack of knowledge of the demands of national and international markets. On the other hand, the results show that the relative remuneration of the capital producer for the 2015-2016 cycle was: 88%, 89% and 92% for small, medium and large producers; respectively, which reflects the competitiveness of producers in terms of the price-cost ratio.

Tectonic instability is the most distinctive feature of the geologic evolution of southern Mexico since the Precambrian. Although geochronometrical records in this region do not extend beyond about 1,100 m.y. b.p., clearly there were older sedimentary, magmatic and tectonic events that were obscured by subsequent geological activity. The granulitic Oaxacan Complex developed as a result of the first orogeny known in the area. Its tectonothermic culmination, some 1,025 ± 75 m.y. ago, eventhough did not destroy the original character of the involved rocks completely, their isotopic systems were disturbed to the extent that absolute dating has not yet penetrated beyond this pervasive orogenic event. Paragneissic (calcareous, pelitic and arkosic) and orthogneissic (anorthositic, gabbroid and graniticsyenitic) rocks, composing the Oaxacan Complex represent, respectively, miogeoclinal sedimentation and cratonic magmatism of unknown age, but probably restricted to the Proterozoic. The following 500 m.y. include a protracted event of uplift and erosion, that exposed the Oaxacan Complex after its generation at depths of 20 to 30 km and temperaturas exceeding 700°C, as suggested by its petrology. In order to continue, download the full paper in PDF.

The Delegación Álvaro Obregón is located on the mountain slopes and piedmont of the volcanic range Sierra de las Cruces. The piedmont is an urban area and it is here where most of the damage in Mexico City, as floods, landslides and collapse of old mining tunnels, occurs each year. These problems are related to lithology, landform and human activity. Deposits from the San Miguel volcano consist of ash, pumice, pyroclastic flows and lahars, as well as conglomerate and fanglomerate. The predominant landform is a sloping surface dissected by deep parallel ravines and their tributaries… in order to continue, download the full paper in PDF.

The Quaternary eruptive dynamics from northeastern Michoacan allowed the identification of two types of events. The first one is widespread and it is represented by cinder cones and flows; the second one was found to have a local distribution (Valle de Santiago region) and it is characterized by the presence of explosion craters Xalapascos or maars. The rock mineralogy is essentially homogeneous. It is constituted by plagioclase, olivine, orthopyroxene, clinopyroxene and oxides of Fe-Ti. These lavas exhibit a variable microscopic texture that led to the large petrographic diversity in these rocks. Major elements show the predominante of basic terms, which has permitted the identification of three groups with a chemical character as follows: 50-58%. 48-55%, and 56% of SiO2. This aspect agrees with the petrographic variability defined herein, the two first terms are the most abundant in the field... In order to continue, download the full paper in PDF.

A review of the geologic history from the Trassic to the Cretaceous is presented. In accordance with existing bibliography and the author's experience, the tectonic processes leading to the formation of different rocks during the period from 225 to 60 m.y. ago, are shown by means of stratigraphic description. Therefore, the sea/earth relationship (paleogeography) shows the uneven distribution of rocks, marine as well as continental (terrigenous and volcanic). Some considerations on the origin of geosynclines are made, in the sense that these could be of tectonic origin or stratigraphic units, products of deformation processes in the subduction areas, which are sometimes related to the effect of plate collisions or caused by the plates themselves. In somes cases, paleogeographic maps should be considered as models, since it is impossble, given the actual information, to restore past geologic events. In many cases, especially those of Mesozoic rocks or even older rocks, the original evidence of the deposit was altered or eroded, in the first case by different tectonic processes and metamorphism; and in the second, when the rocks remained emerged by distinct orogenies and subjected to subaerial or submarine erosion processes.

El área de Xilitla se localiza cerca del poblado del mismo nombre, en el Estado de San Luis Potosí, en la Sierra Madre Oriental (Figura 1) y ha sido estudiada por varios autores, entre los que destacan Heim (1926y 1940), Bonet (1953 y 1956) y Suter (1980 y 1984). Seibertz realizó la prospección geológico-paleontológica del área, como parte del Proyecto "El Cretácico medio del Norte de México", financiado por la Sociedad Alemana de Investigaciones (contribución al IGCP Proyecto58 "Mid-Cretaceous Events")... In order to continue, download the full paper in PDF.

The oldest stratified rock recognized in NW Sonora (and in Mexico) are deformed muscovite-quartz schists, quartzites, and biotite-quartzofeldspathic gneisses near Caborca, which are cut by calcalkaline intrusives ranging from 1,710 to 1,750 m.y. in age. Southwest of Caborca, upper amphibolite facies layered quartzofeldspathic and amphibolitic gneisses were apparently deformed and metamorphosed at about 1,660 ± 15 m.y. ago, concealing original lithologies and ages. In northeastern Sonora, a younger belt of eugeosynclinal strata, about 1,680 ± 20 m.y. old was tightly folded and metamorphosed to greenschist facies about 1,650 m. y. ago. Numerous granitic plutons intruded into the older Precambrian crust about 1,410 to 1,440 m.y. ago. These major intrusive masses are not known to have been accompanied by regional sedimentation or deformation. Rare, small plutons of micrographic granite added to the Precambrian crystalline complexes about 1,100 m.y. ago, are the youngest Precambrian igneous rocks recognized... In order to continue, download the full paper in PDF.

Volcán de Colima (103°37'W, 19°30'45"N) has a very intense eruptive history and is considered the most active volcano in Mexico. Its documented background of the historical eruptions varies from ambiguous relations of astonished eyewitnesses, to scientific papers written by investigators from different countries.Volcán de Colima has had practically all types of volcanic eruptions, from freatic explosions located in the summit dome, to Plinian eruptions whose products were spread by the wind up to several kilometers from the site of origin.… in order to continue, download the full paper in PDF.

Proceedings of the VII International Congress on Pacific Neogene Stratigraphy, Mexico City, October 4-6, 1999.  Preface This special volume presents contributions from the VII International Congress on Pacific Neogene Stratigraphy, held at the Universidad Nacional Autónoma de México in Mexico City, Mexico on October 4-6, 1999, sponsored by the Regional Committee on Pacific Neogene Stratigraphy, SNS, IUGS, with the collaboration of the Instituto de Ciencias del Mar y Limnología, UNAM. The Congress was attended by over 50 geoscientists from many countries of the circum-Pacific region. The main theme of the congress was “Pacific Neogene Studies Towards the 21st Century”, with the aim of exploring... DOWNLOAD THE FULL ARTICLE.

El día 11 de abril de 1988 falleció el Dr. Francisco José Fabregat Guinchard, investigador y profesor universitario distinguido y miembro del Instituto de Geología de la U.N.A.M. El Dr. Fabregat nacido en la Ciudad de México el 29 de noviembre de 1909 y realizó sus primeros estudios en el Colegio Alemán de esta misma ciudad. En España completo sus estudios de bachillerato y de licenciado en Ciencias, en la Universidad de Barcelona. El 12 de febrero de 1959 la Universidad de Madrid le otorgó, con grado de sobresaliente, el título de Doctor en Ciencias. Durante su formación académica fue becario y colaborador del Consejo Superior de Investigaciones Científicas de España, profesor de la Universidad de Barcelona y vocal del Colegio de Licenciados y Doctores de Barcelona... In order to continue, download the full paper in PDF.