Geology of the northern Andes; An overview
The northern Andes in Colombia form three great ranges, the Cordilleras Oriental, Central, and Occidental (Fig. 1). Other ranges include the Sierra Nevada de Santa Marta, Guajira Peninsular ranges, and physiographic extensions of the Cordillera Oriental northeast into Venezuela, including the Sierra de PerijÃ¡ and the Cordillera de MÃ©rida (Venezuelan Andes). The present physiographic expression is the result of Tertiary (Neogene) uplift. The Cordillera Occidental is underlain by deformed oceanic crust, perhaps allochthonous as judged from the low metamorphic grade of Mesozoic rocks in the north (see chapter by Escalante, this volume; Duque-Caro, 1990); most of the Cordillera Central, Cordillera Oriental, Sierra de PerijÃ¡, and Cordillera de MÃ©rida are underlain by continental crust. The Sierra Nevada de Santa Marta and ranges on the Guajira Peninsula are probably underlain by both types of crust, and oceanic segments on the north sides are probably allochthonous. In the following summary of the regional geology, the main mountain ranges will be described from east to west. The Sierra Nevada de Santa Marta, Guajira ranges, and sedimentary basins will be discussed last. Some of the generalized descriptions are modified from Case and others (1984). Geologic maps by Bellizzia and others (1976), Arango C. and others (1976), MartÃ—n F. (1978), Case and Holcombe (1980), Etayo-Serna and others (1983, 1986), and Case and others (1984) provide a regional framework for this summary. BÃ¼rgl (1961,1973), Irving (1975), Etayo-Serna and others (1983, 1986) and GonzÃ¡lez and others (1988) provided very useful syntheses of the pre-1960 to 1970 literature for
Figures & Tables
The Caribbean Region
The result of a major international effort involving authors and organizations from 13 countries, this volume summarizes the complex geology and tectonic evolution of the Caribbean plate and its relation to the adjacent North American, South American, Nazca, and Cocos plates. Focuses on regional geology and geophysics, magmatic processes, neotectonic features, geologic hazards, and energy and metallic resources. Contrasting views for the Mesozoic and Cenozoic geological evolution are presented in chapters on plate tectonics and mantle surge tectonics. Chapters on marine geology and geophysics are new syntheses for the entire Caribbean region. Highlights of the volume include extensive bibliographies and new syntheses of stratigraphic-lithologic columnar sections, seismicity, gravity and magnetic anomalies, neotectonic features, resource data, and crustal properties.