This welcome volume provides a geological account of the history, growth and evolution of the Indian Subcontinent. The Indian Shield is thought to have grown and evolved in the Precambrian, and then been reconstituted by later events and processes in the Phanerozoic. That provides the form of this book, within which the approach is to discuss the regional geology starting with the oldest sequences.
The rocks range in age from 3400 million years to the Quaternary. Two thirds of the book concentrates on the Archean, which in India is sub-divided into proto-continents, typically separated by Gondwana rift basins. The Southern India Granulite belt remains an area of significant interest internationally, and as more geochronological data become available worldwide it now appears that such terrains are a feature of the relatively late Archean. Subsequent chapters tackle issues such as Paleozoic basins and the evolution of life forms, the Gondwana supergroup, its origins and evolution, Gondwana break-up and the development of the Himalayas. The last major section is on Quaternary geology and seismicity, before a brief epilogue on correlation and the evolutionary history of the Indian shield.
Throughout the emphasis is on the rocks, and their relationships in the field, with lots of field photographs and regional geological maps. These provide an excellent introduction to the geology of India, the references are comprehensive, and controversies over preferred interpretations are discussed where appropriate. Nonetheless it would have helped this reader, who is not very familiar with the geography of India, to have more in the way of larger scale maps showing, for example, the locations of the different Archean schist belts and how they related spatially to one another.
The ages of different units and geological events is increasingly an integral part of the geology of any area. These are discussed in the text, but there are no tables of even the key ages, nor any summary figures of when different events occurred, which would have made it easier to understand the context.
The tone of the book is reflected in the wealth of figures of field geology and local maps, but with much less in the way of summary age and tectonic diagrams. I would have enjoyed a smattering of such figures that might have been readily used in lectures and seminars, and hence brought the geology of India to a wider audience. Despite such concerns, I enjoyed this introduction to the Indian Shield, and it deserves to be widely used by those seeking to become familiar with different aspects of the geology of India.
Reviewed by Chris Hawkesworth
INDIAN SHIELD: PRECAMBRIAN EVOLUTION AND PHANEROZOIC RECONSTITUTION, by A.B. Roy & Ritesh Puohit, 2018. Published by: Elsevier, 398 pp. pbk. ISBN 9780128098394. List Price: £119.00. W:
www.elsevier.com