Salient Depositional Structures from Bombay Volcanic Complex, Western Deccan Volcanic Province, Deccan Flood Basalt, India

The undersigned was initiated to the Deccan traps in the very beginning of his career (1984) by one of the then stalwarts in Deccan trap studies in GSI. Hence the interests in DVFB studies are of primary nature. Subsequent involvement of the author in structural mapping and exploration hampered the further studies in the field of volcanology. However after superannuation from the government job as professional geologist, the author renewed his interest in the field where from he started his professional career. Though enormous literature on the Deccan volcanism and LIP’ s of the world has flooded the academic world during this period but it was felt that the classic depositional features of the volcanic rocks didn’t find the importance they deserve in the academic world. Probably the miniscule volume of these rocks did not invoke sufficient interest in the publication world. This is why precisely the author thought of bringing out a small write-up to acquaint the students of volcanology with this small area which in my opinion is the museum of the volcanic features. The author has mapped on large scale about 300 kilometer square area within the Bombay volcanic complex and observed the depositional structures, nature and composition of clasts, their mutual relation with the volcanic ejecta and other volcanic rocks. The geology of this area is so diverse that as much as 12 different varieties of combinations of litho units have been recorded. Evidences of violent volcanism have also been recorded besides these volcanoclastic rocks largely being products of sub aerial effusion. A detailed observation sheet has been provided here in this write-up for the first hand information of the nature and components of various deposits. Another objective of publishing this material is to make the observation and work of a professional geologist reach to the reader, who are generally fed by the academicians with their very limited field exposure and far reaching inferences drawn based on very meager data. Here voluminous observational data is supplied to the reader, who is free to draw his own conclusions and interpretations based on the content published in this small book. Though the author himself has not concluded anything about the volcano-tectonic environment and mechanism of emplacement of these rocks, the observations supplied besides the depositional structures and micro-textures in this book, together make it a substantial content to arrive at some logical end, if not, the author is very optimistic about this book being able to generate an interest in the reader about the field of volcanology. If that is done the purpose of writing this small book will be served. I take this opportunity to mention here that the undersigned will bring out a full book on the BVC very soon.