Proterozoic

Geological correlations of East Antarctica with adjoining continents have been puzzling geologists ever since the concept of a Gondwana supercontinent surfaced.

The Metazoa, today taken as a synonym of Animalia, comprises a large grouping of organisms that may be characterized as being multicellular and heterotrophic, i.e., they do not synthesize their own food, but obtain it from external sources.

The sad news of George Crumb's death was announced on 6 February 2022, shortly after these recordings from a concert in Holland in 1978 were discovered in the KRO-NCRV archives in Hilversum.

This GeoGuide provides an overview of the geology of Alnö, combined with an up-to-date field itinerary. Covering all major geological aspects, it offers an essential summary of Alnö and its intriguing magmatic rocks in a compact form suitable for field excursions and home study alike. As one of the type localities for carbonatite, the late Proterozoic Alnö ring complex has been a crucial site for carbonatite-related research (next to the Fen complex in Norway), and provided one of the earliest test beds for this unique group of igneous rocks. Five geological excursions introduce the visitor to the most rewarding outcrops, including detailed descriptions and a wealth of high-quality colour photographs. The excursions are complemented by a detailed review of the history of scientific investigation on Alnö and, in particular, a catalogue of exotic and common minerals associated with the complex’s carbonatitic and alkaline silicate rocks. Finally, a summary of its trace element and isotope geochemistry as well as a brief outlook on Alnö’s potential as a future source of Rare Earth Elements (REEs) completes the book.

This book provides a comprehensive overview of the geological evolution of the Northern Andes and contiguous shield areas, with a focus upon Colombia. Updated geological interpretations are supported by modern lithogeochemical, seismic, gravity and magnetic data and radiogenic isotope and radiometric age determinations. The composite data permits a detailed interpretation of the tectono-magmatic history of the Northern Andean Block, including the Andes of Colombia, northern Ecuador, western Venezuela and eastern Panamá.

This book provides a comprehensive overview of the geological evolution of the Northern Andes and contiguous shield areas, with a focus upon Colombia. Updated geological interpretations are supported by modern lithogeochemical, seismic, gravity and magnetic data and radiogenic isotope and radiometric age determinations. The composite data permits a detailed interpretation of the tectono-magmatic history of the Northern Andean Block, including the Andes of Colombia, northern Ecuador, western Venezuela and eastern Panamá.