M.N. Balasubrahmanyan, Geology and Tectonics of India: An Overview, International Association for Gondwana Research Memoir vol. 9, International Association for Gondwana Research, Japan (2006), p. 204 Price: India—Rs. 700.

Abstract

The book on the “Geology and Tectonics of India: An Overview” by Dr. Balasubrahmanyan represents a comprehensive and comprehensible geological and tectonic description of the Indian subcontinent. I am very impressed by the author's ability to encompass various aspects of the geology and tectonics of India in a book of 204 pages, and I congratulate the author on such an excellent, impressive piece of work.

Numerous studies have been conducted on the geology and tectonics of the Indian subcontinent in the last three decades, and several synthesis books have also been published. However, none of the published books have given such a broad and comprehensive overview on the geology and tectonics of India like this one. Dr. Balasubrahmanyan has extensively surveyed the relevant literature, successfully digested the published works and admirably produced an excellent synthesis of existing knowledge about the geology of India. Undoubtedly, the publication of this book is a great contribution to the international geology community for better understanding the geology and tectonics of India.

The book starts with a brief geological outline of the major tectonic divisions of India, including Peninsular India, southern India, eastern India, central India, western India, Purana Basins, Rajmahal Volcanic Province, Deccan Trap, Himalaya, Ganga Foredeep, etc. This general geological outline is followed by a short but succinct geophysical summary, especially on magnetic, deep seismic sounding, seismic and thermal aspects of these tectonic divisions. These two chapters provide the background for the next nine chapters that give more detailed descriptions of the geology of the major tectonic divisions in India, starting from the oldest but well-known Dhawar Craton, through Granulite Province, eastern Indian Shield, central Indian Cratons, western India, Purana Basins and Gondwana Basins, to the youngest and famous Deccan Trap and Himalaya.

In a chapter on the Dhawar Craton, the author not only presents a timely summary of major basement gneisses (e.g. Peninsular Gneisses I and II) and greenstone belts (Sargur- and Dhawar-type) that constitute the craton, but also gives an overview of gold and sulphide mineralization in this craton. In the next chapter titled The Granulite Province, the author gives a coherent account of the Southern Granulite Terrane (SGT) and the Eastern Ghats Mobile Belt (EGMB), both of which are hot-spots in reconstruction of Rodinia and a Pre-Rodinia supercontinent (Columbia or Nuna), though the author does not directly manifest their significance in these aspects. As summarized by the author, recent publications show that the SGT and EGMB can be further subdivided into a number of small blocks or massifs with different geological features, which demonstrates the complex histories related to the accretion and collision of these terranes. In the next two chapters entitled The Eastern Indian Shield and The Central India Craton, the author mainly focuses on the Singhbhum and Bastar Cratons and their associated mobile belts. Compared with the Dhawar Craton, Southern Granulite Terrane (SGT) and Eastern Ghats Mobile Belt, the Singhbhum and Bastar Cratons are less known to geologists from outside India. I believe that after reading these chapters the reader can be more familiar with the immensely complicated geology and tectonics of these two cratonic blocks and surrounding mobile belts. The fold belts of Aravalli and Delhi flanked by the Trans-Aravalli Basin to the west and the Vindhyan Basin to the east are described in a chapter titled Western India. The author focuses on the stratigraphy and Paleo-Mesoproterozoic tectonic evolution of these fold belts.

Chapters 8 and 9 discuss a number of Mesoproterozoic to Neoproterozoic Purana Basins and late-Paleozoic to Mesozoic Gondwana Basins, with emphases on their stratigraphy, structure, age, tectonics and mineral resources. In discussing the Purana Basins, Dr. Balasubrahmanyan suggests that sediments north of the Son-Narmada-Tapti Lineament may have formed within a broad basin (Vindhyan Basin), whereas those to the south may have been deposited in different basins. As for the Gondwana Basins, Dr. Balasubrahmanyan divides the sediments into the Lower and Upper Gondwana Basins, which show different stratigraphical sequences, structures, tectonics and ages.

In chapter 10, the author presents arguments for and against the model that the Deccan basalts were derived from the head of a mantle plume whose tail is now at Reunion Island. Since the 1970s, Indian, Chinese and many western geologists have carried out extensive investigations on the geology and tectonics of the Himalaya and produced numerous data and interpretations. In chapter 11, Dr. Balasubrahmanyan incorporates a vast amount of up-to-date information and synthesizes the general geology and tectonics of the Himalaya. Especially, the author stresses that the stratigraphy of the Himalaya is a key to understanding the metasedimentary rocks that constitute the mountain range. The final two chapters of this book discuss the Cenozoic formations and Quaternary geology of India and their potential for oil and gas reserves.

The book contains a very large number of diagrams and geological maps which will certainly help researchers in understanding the geology of India, but it is a pity that few geological maps are with latitudes and longitudes, and the quality of many diagrams and maps is very poor. Although the overall English exposition is adequate, there are a number of English errors and typos. Also, few references in the bibliography were published in this century. All these need to be rectified if the author plans for a second edition. Notwithstanding these shortcomings, I reiterate that this book deserves to be read by all who are interested in the geology and tectonics of India.