Amos Salvador

The Gulf of Mexico Basin

Eighteen chapters deal with the entire Gulf of Mexico basin. Included are significant contributions from Mexican geologists. Nine topical chapters cover regional aspects of physiography and bathymetry, structural framework, the basement crust, salt tectonics and listric faulting, igneous activity, seismic stratigraphy, oil and gas resources, mineral resources and geopressured-geothermal energy, and ground water. Six chapters summarize regional stratigraphy and paleogeography for the pre-Triassic, Triassic-Jurassic, Lower Cretaceous, Upper Cretaceous, Cenozoic, and late Quaternary. Also included is a synthesis of the origin and development of the Gulf of Mexico basin. Six 4-color plates summarize the bathymetry, natural resources, tectonics, and basement structure and subcrop of the region, and provide a stratigraphic correlation chart and geologic cross sections.

The Tertiary and the Quaternary are here to stay

In 1989 and 2000, the International Commission on Stratigraphy (ICS) published geologic time scales in which the term Tertiary had been eliminated. In the time scales published by the ICS in 2004, the term Quaternary was also eliminated, the Cenozoic shown as composed of two systems, the Paleogene and the Neogene, the Neogene extending to the present. Was there any logical basis for these changes? A review of the geologic literature since 1980 (19 journals of extensive distribution and a considerable number of geologic maps, time scales, and stratigraphy textbooks as well as the GeoRef) clearly indicates that the Tertiary and the Quaternary have long been (and are now) in widespread use by geologists the world over, and that their use has not declined at all during the last 25 yr. They are very useful terms in geologic work, essential for clear communication among geologists. Paleogene and Neogene have received increasing use during the last 10 yr because they are also useful terms. Quaternary is probably the stratigraphic term most frequently used in the geologic literature. Tertiary is used as the pre-Quaternary part of the Cenozoic by most geologists; some, however, prefer to use Paleogene and Neogene instead of Tertiary. But it should not be a question of either Tertiary or Paleogene and Neogene; all three are needed, as are Cenozoic, Paleocene, Eocene, Oligocene, Miocene, and Pliocene, to express various degrees of precision in stratigraphic assignation and dating. All should be recognized as units of a standard geologic time scale. Geologists should retain a choice of what they think better fits their needs. The preferred time scale, therefore, should have the Cenozoic Erathem comprising the Tertiary and Quaternary systems, and the Tertiary including the Paleogene and Neogene subsystems. Past attempts to eliminate the Tertiary and Quaternary have been ignored. Recent attempts will not succeed either. The Tertiary and the Quaternary are here to stay, certainly as long as geologists continue to use them, as they have, and continue to oppose the ill-advised efforts to discard them from the geologic time scale.

Late Triassic-Jurassic Paleogeography and Origin of Gulf of Mexico: ABSTRACT

The basic structural and stratigraphic framework of the Gulf of Mexico was established by events that occurred during the Late Triassic and the Jurassic. Cretaceous and Tertiary events only accentuated and modified this framework. During the Late Triassic and Early Jurassic, continental conditions prevailed over most of the southern part of the North American plate. Marine deposition was restricted to parts of western and central Mexico that were covered by embayments of the Pacific Ocean. As the North American plate started to separate from the South American and African plates, tensional grabens began to form in the area. They were filled with red beds and volcanic rocks. It was not until late in the Middle Jurassic (Callovian) that Pacific marine waters began to reach the Gulf of Mexico area across central Mexico. They intermittently flooded the preexisting grabens and, between floods, evaporated to produce extensive salt deposits (Louann Salt). The salt differed markedly in thickness according to the rate of subsidence in the grabens. Little or no salt was formed in the intervening high areas. During the Late Jurassic, Pacific marine waters progressively covered an increasingly large part of the Gulf of Mexico and surrounding areas as a result of continued subsidence, sea-level rise, or both. Connection with the Atlantic, however, was not established until late Kimmeridgian or Tithonian time. End_of_Article - Last_Page 520------------

Sources of Energy

During the second half of the 20th century, fossil fuels (oil, natural gas, and coal) provided 85–95% of the total energy consumed in the world. The other 5–15% was supplied mainly by hydroelectric and nuclear power. The fossil fuels can be used to power land vehicles, ships, and aircraft and to generate electricity. Hydroelectric and nuclear power can be used only to generate electricity. To predict what sources will supply the demand for energy during the 21st century, this chapter reviews the essential information about past production and consumption, estimated reserves and resources, ultimate recovery, and potential future availability of all presently known sources of energy. This review indicates that fossil fuels will remain as the principal source of the energy consumed in the world during the 21st century and certainly during its first half.

The contributions od Dr. Salvador Reguant to the dissemination of the principles of stratigraphic classification and nomenclature

A look at the curriculum vitae and the long list of publications of Salvador Reguant cannot fail to astonish us for the diversity of his interests and for the intensity and breath of his activities. His publications cover both geologic and religious themes, contribute to the spreading of general scientific information, and often deal with the teaching of the earth sciences. His contributions to geology range from the interpretation of the history of our planet and of the origin and evolution of its continents and oceans, to the most detailed studies of small intervals of the stratigraphic succession and of the fossils which they contain. Three subjects of study evidently favored by Salvador have been the stratigraphy of the Tertiary, particularly of the Paleogene of northeastern Spain (Catalunya, the Ebro Basin, and the Pre-Pyrenees), the paleontology of the briozoans, and the concepts, mutual relationships and terminology of biostratigraphy and chronostratigraphy.