This paper is a review of the standard stratigraphic column accepted by many workers for the Lower Cretaceous (Berriasian‐Aptian) of the Arabian Gulf. Type sections, synonymy and summary paleontological details are included. A historical introduction provides an explanation of the profusion of formational and member names. The observed fades variation in the region, both vertical and lateral, can best be understood in terms of the migration of predominantly shallow water carbonate facies‐belts across a shelf. Two, predominantly carbonate, cycles can be recognised, with the maximum development of the marginal clastic fades occurring within the upper cycle.
The Great Whin Sill, which was intruded in Upper Carboniferous to Lower Permian times, has been sampled at 36 sites in Northumberland and Durham. It was found to be magnetically stable, the site mean direction of magnetization being 187~.8-4".9 and the mean pole position lying in latitude 37O-3 N longitude 168O.9 E. The distribution of the mean directions of magnetization at these sites is not circular but oval, with the variation in the direction of the palaeomagnetic longitude about twice that in the direction of palaeomagnetic latitudes. However the poles calculated from the site mean directions of magnetization have a circular distribution, and this observation leads to proposal of a method of calculating the errors associated with the palaeomagnetic pole positions.
Das Beeken von Mexiko befindet sich im Zentrum des Transmexikanisehen Vulkangfirtels, einer Ost-West-Struktur, die den nordamerikanischen Kontinent entlang des 19. Breitengrades durehschneidet.Pal~iomagnetische Messungen legen die Vermutung nahe, dab 9. (Guadalupe-und Chichinautzin-Gruppe) der 7 vulkanischen Phasen, die das Becken formten, von wahrscheinlieh kurzer Dauer waren. Die Chiehinautzin-Gruppe, die das Becken im Siiden abschnfirte, mul3 sich grundsStzlich in den letzten 700000 Jahren gebildet haben.Die vulkanische T:~itigkeit, die im Oligozfin begann und sieh kontinuierlich bis in die heutige Zeit fortsetzte, f6rderte naehweislieh im wesentliehen andesitisehe Produkte.
AbstractTile basin of Mexico lies in the center of the Trans-Mexiean Volcanic Belt, an east-west structure which dissects the North American Continent along the 19th parallel. Paleomagnetie measurements suggest that two of the seven eruptive phases --Guadalupe Group and Chiehinautzin Group --that formed the basin, probably were of short duration; the Chiehilmutzin Group, which finally closed the basin to the south, must have been formed principally in the last 700,000 years.The volcanic activity which began in Oligoeene time and has continued until the present, has been proved to be essentially andesitie in composition.
R6sum6Le bassin de Mexieo se trouve au centre de la eeinture voleanique de Mexico, une structure est-ouest qui reeoupe le continent nord-Amerieain pr6s du 19 e parall61e. Les mesures pal6omagn6tiques eonduisent 5 supposer que deux des sept phases d'aetivit6s volcaniques, celles de la Guadaloupe et du Chiehinautzin, 6talent eourtes. Les roches du Groupe de Chiehinautzin, fermant te bassin au sud, ont 6t6 form6es pendant les derniers 700,000 ans.L'aetivit6 volcanique, qui a d6but6 5 l'Oligocbne et se continue encore aetuellement a une charaet6re essentiellement and6sitique.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.