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Geology of Rajasthan (Northwest India) Precambrian to Recent
Journal of Asian Earth Sciences 21 (2003) 527 www.elsevier.com/locate/jseaes
Book Review Geology of Rajasthan (Northwest India) Precambrian to Recent A.B. Roy, S.R. Jakhar (Eds.); Scientific Publishers (India), Jodhpur, 421 pages, Hardbound Among the places I have visited in India, Rajasthan is my favorite; one tour guide I have describes Rajasthan as “India at its exotic and colorful best”. This is the home of the maharajas, the Moghuls, luxurious palaces, battle-scarred forts, the barren Thar Desert, coexisting camels and elephants, the pink city of Jaipur, and the blue city of Jodhpur. The geological history of Rajasthan is as rich and varied as its culture, and the distinguished Precambrian geologist A.B. Roy has joined forces with paleontologist/stratigrapher S.R. Jakhar, to produce a new comprehensive summary of Rajasthan geology. This book is not the first of its kind; I am aware of two similar volumes: “The Precambrian geology of the Aravalli region, southern Rajasthan and northeastern Gujarat”, by S.N. Gupta et al. (Memoirs Geol. Survey of India, vol. 123, 262 pp, with four colored geological maps and four structural maps, scale 1:250,000, 1997) and “Geology of Rajasthan”, by A. Sinha-Roy et al. (Geol. Soc. India, Bangalore, 1998, 278 pp). Those engaged in, or considering serious geological work in Rajasthan will probably want to consult all three of these. The Roy and Jakhar book, like the other two volumes, presents the geology of Rajasthan in stratigraphic order, with individual chapters on the Archean basement rocks, the Paleoproterozoic Aravalli and Mesoproterzoic Delhi Fold Belts, the Meso-Neoproterozoic Vindhyan Supergroup, the Neoproterozoic magmatic and sedimentary sequences, the Paleozoic to Tertiary stratigraphy, Mesozoic – Cenozoic magmatism, and Quaternary geology and neotectonics. There are also introductory chapters on the physiography, crustal geophysics and geological framework, and a summary chapter on the geological history of Rajasthan. The book contains 350 black & white illustrations and 93 maps, although many of the photographs (and especially the few satellite images) are of poor quality, and some of the geological maps (especially the detailed ones) show no latitudes and longitudes. There is a color foldout summary
geological map of Rajasthan (scale 1:3 million) that is very similar to the one in the Sinha-Roy et al. volume. The most useful geological maps of Rajasthan, however, are the four colored ones and four structural ones (scale 1:250,000) in the Gupta et al. volume. The subject index in the Roy and Jakhar volume is more than a bit mixed-up, alphabetically, and it would have been useful if the tables of rock analyses could have been somehow keyed to the geological maps. The introductory chapters and the ending summary present a good overview of the geography, geomorphology, drainage and overall geological evolution of Rajasthan, although I found the geophysics chapter a bit thin, containing a tantalizing mention of lithosphere tomography, without much detail. The individual chapters on the major chronostratigraphic units are full of detailed and useful information, but one gets the overall impression that the stratigraphic nomenclature and relationships between many rock units are actively debated among the various research groups working in Rajasthan. I suspect that much of this has to do with the generally poor state of modern geochronology in the region, a point recognized by the authors and their colleagues, who have made valiant attempts to improve the situation in their research programs. Another factor relates to the variability of outcrop exposure, which ranges from near zero (in the Thar Desert) to superb (e.g. in the Mt. Abu region of southern Rajasthan). Overall, Roy and Jakhar have succeeded in compiling a huge quantity of useful geological information, much of it from their own countless days of field and laboratory work. There is far more work to be done in Rajasthan, including mapping, geochronology, paleomagnetic work, geochemistry and geophysics. Those who engage in this over the next several decades will find this book a very useful asset.
1367-9120/03/$ - see front matter q 2003 Elsevier Science Ltd. All rights reserved. PII: S 1 3 6 7 - 9 1 2 0 ( 0 2 ) 0 0 1 8 4 - 0
Lewis D. Ashwal School of Geosciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa 11 September 2002Accepted 11 September 2002
Book Review Geology of Rajasthan (Northwest India) Precambrian to Recent A.B. Roy, S.R. Jakhar (Eds.); Scientific Publishers (India), Jodhpur, 421 pages, Hardbound Among the places I have visited in India, Rajasthan is my favorite; one tour guide I have describes Rajasthan as “India at its exotic and colorful best”. This is the home of the maharajas, the Moghuls, luxurious palaces, battle-scarred forts, the barren Thar Desert, coexisting camels and elephants, the pink city of Jaipur, and the blue city of Jodhpur. The geological history of Rajasthan is as rich and varied as its culture, and the distinguished Precambrian geologist A.B. Roy has joined forces with paleontologist/stratigrapher S.R. Jakhar, to produce a new comprehensive summary of Rajasthan geology. This book is not the first of its kind; I am aware of two similar volumes: “The Precambrian geology of the Aravalli region, southern Rajasthan and northeastern Gujarat”, by S.N. Gupta et al. (Memoirs Geol. Survey of India, vol. 123, 262 pp, with four colored geological maps and four structural maps, scale 1:250,000, 1997) and “Geology of Rajasthan”, by A. Sinha-Roy et al. (Geol. Soc. India, Bangalore, 1998, 278 pp). Those engaged in, or considering serious geological work in Rajasthan will probably want to consult all three of these. The Roy and Jakhar book, like the other two volumes, presents the geology of Rajasthan in stratigraphic order, with individual chapters on the Archean basement rocks, the Paleoproterozoic Aravalli and Mesoproterzoic Delhi Fold Belts, the Meso-Neoproterozoic Vindhyan Supergroup, the Neoproterozoic magmatic and sedimentary sequences, the Paleozoic to Tertiary stratigraphy, Mesozoic – Cenozoic magmatism, and Quaternary geology and neotectonics. There are also introductory chapters on the physiography, crustal geophysics and geological framework, and a summary chapter on the geological history of Rajasthan. The book contains 350 black & white illustrations and 93 maps, although many of the photographs (and especially the few satellite images) are of poor quality, and some of the geological maps (especially the detailed ones) show no latitudes and longitudes. There is a color foldout summary
geological map of Rajasthan (scale 1:3 million) that is very similar to the one in the Sinha-Roy et al. volume. The most useful geological maps of Rajasthan, however, are the four colored ones and four structural ones (scale 1:250,000) in the Gupta et al. volume. The subject index in the Roy and Jakhar volume is more than a bit mixed-up, alphabetically, and it would have been useful if the tables of rock analyses could have been somehow keyed to the geological maps. The introductory chapters and the ending summary present a good overview of the geography, geomorphology, drainage and overall geological evolution of Rajasthan, although I found the geophysics chapter a bit thin, containing a tantalizing mention of lithosphere tomography, without much detail. The individual chapters on the major chronostratigraphic units are full of detailed and useful information, but one gets the overall impression that the stratigraphic nomenclature and relationships between many rock units are actively debated among the various research groups working in Rajasthan. I suspect that much of this has to do with the generally poor state of modern geochronology in the region, a point recognized by the authors and their colleagues, who have made valiant attempts to improve the situation in their research programs. Another factor relates to the variability of outcrop exposure, which ranges from near zero (in the Thar Desert) to superb (e.g. in the Mt. Abu region of southern Rajasthan). Overall, Roy and Jakhar have succeeded in compiling a huge quantity of useful geological information, much of it from their own countless days of field and laboratory work. There is far more work to be done in Rajasthan, including mapping, geochronology, paleomagnetic work, geochemistry and geophysics. Those who engage in this over the next several decades will find this book a very useful asset.
1367-9120/03/$ - see front matter q 2003 Elsevier Science Ltd. All rights reserved. PII: S 1 3 6 7 - 9 1 2 0 ( 0 2 ) 0 0 1 8 4 - 0
Lewis D. Ashwal School of Geosciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa 11 September 2002Accepted 11 September 2002