In this paper, ammonite biostratigraphy and biogeography are used as the basis for an investigation of the origin of the Gulf of Mexico. Three key observations indicate a Pacific rather than an Atlantic origin for the Gulf of Mexico:
1) The Bajocian ammonite Stephanoceras, which occurs throughout the western American margin (Alaska, Canada, United States, Venezuela, Peru, Argentina, and Chile), has also been recorded in the base of the Tecocoyunca Series in Oaxaca (southern Mexico).
2) The Bathonian and Callovian transgressive cycles, which have been recorded in eastern and southeastern Mexico, have been dated on the basis of the ammonites Wagnericeras and Reineckeia, which are of East Pacific affinity and have been recorded in the subsurface of the Gulf of Mexico coastal plain. The transgressions started in Oaxaca and ended with the Gulf of Mexico opening around the Tampico and Campeche areas, as well as in locations around the margins of the Gulf (e.g., southeastern United States and Cuba) during the early Oxfordian, justifying this age for the origin of this paleogeographic province.
3) In Mexico, several groups of known cephalopods, from the Permian to the Jurassic, are related only to fauna in the Pacific province. They occur in isolated sequences located to the west of the present coastline of the Gulf of Mexico.
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Carbon dioxide (CO 2) is the main compound identified as affecting the stability of the Earth's climate. A significant reduction in the volume of greenhouse gas emissions to the atmosphere is a key mechanism for mitigating climate change. Geological storage of CO 2, or the injection and long-term stabilization of large volumes of CO 2 in the subsurface in saline aquifers, in existing hydrocarbon reservoirs or in unmineable coal seams, is one of the more technologically advanced options available. A number of studies have been carried out and are reported here. They are aimed at understanding the safety, physical and chemical behaviour and long-term fate of CO 2 when stored in geological formations. Until efficient, alternative energy options can be developed, geological storage of CO 2, the subject of this volume, provides a mechanism to reduce carbon emissions significantly whilst continuing to meet the global demand for energy.