Many of the problems which arise during a study in structural geology are essentially exercises in three-dimensional geometry. Data acquired from field-observations—strike and dip of planes (beddingplanes, planes of schistosity or cleavage, faults, etc.), the pitch and plunge of lineations (outcrops, slickensides, micro-folds, flow-lines, elongation of mineral components or of inclusions, etc.) and all other related vector data are incorporated in a geological map and in accompanying illustrative sections. Both in the construction of such sections and of related block-diagrams, and in the further study of the structural features of an area, it is frequently necessary to make various calculations. Sometimes, indeed, as in many of the problems of mining geology and in the interpretation of borehole cores, the necessity for calculation arises at an even earlier stage since such fundamentals as the dip and strike of a bedded series are only indirectly derived from the observed data.  <...>

Felsic rocks of the Rooiberg Group, which constitutes the roof of the Bushveld Complex., host the discordant volcanic pipe and associated surrounding pyroclastic and sedimentary rocks, called the Vergenoeg suite. The volcanic pipe is situated at the crossing of strong aerial photo and magnetic lineaments, about in the centre of the four lobes of the Bushveld Complex in the Republic of South Africa.

The Vergenoeg suite constitutes of an uppermost stratiform sedimentary unit, followed by fragmental conformably stratified hematite and hematite-fluorite units. This is followed by a breccia agglomerate and then a basal unit of ignimbrites. A discordant volcanic pipe completes the suite. The Vergenoeg volcanic pipe has a vertical funnel-like shape. At the surface this is about 900 m in diameter, tapering sharply in depth to where it is still open-ended at more than 650 m. Horizontal zoning exists in the pipe, with a hematite-fluorite or gossan cap at surface, followed by a deeper zone of unoxidised magnetite-fluorite, then a magnetite-fayalite transition zone and finally a fayalite zone at the deepest levels. Fluorite, siderite and pyrite veins, dykes and lenses are present throughout all the zones. Contacts between zones are gradual but are sharp with the felsic host rock. Felsite breccias, cemented by fluorite, siderite and pyrite are found at depths.

The Gulf of Mexico Basin is one of the best-known and most highly explored petroleum basins in the world. The literature on the basin is enormous and continues to grow each year. The deep-water part of the basin is now one of the most prolific new provinces in the world, and it is the continued focus for oil and gas exploration. Here the industry leads the world in the application of modern drilling and production techniques.

Gale is pleased to present the third edition of Geo-Data: The World Geographical Encyclopedia. This is the first new edition of Geo-Data since 1989, and it represents a complete revision and updating of that work. The purpose of the book remains unchanged: to provide the reader with the most detailed and comprehensive descriptions available for the physical geography of countries.Geo-Datays focus and design is unique. Many encyclopedias, atlases, and other books provide some information on geography, but it is usually secondary to history, current events, or other topics. In these sorts of references physical geography receives a few paragraphs of coverage per country at best, compared to pages in Geo-Data. Among the few books that can rival Geo-Data coverage, none can match its ease of use. There is no need to hunt from one end of a dictionary or gazetteer to another, searching for details on a country's many different features. In Geo-Data everything is presented in one place. Each of Geo-Datays entries gives the reader a complete portrait of a country’s mountains, fields, forests, deserts, rivers, seas, wetlands, and other features, with additional information on population distribution and natural resources. Key facts and statistics are highlighted at the beginning of each entry. In addition to the country entries, Geo-Data features a World Rankings Appendix, listing the world's tallest mountains, longest rivers, deepest oceans, largest lakes, most populous countries, and other outstanding features.