ROCK MAGNETISM AND PALAEOMAGNETISM OF METEORITE IMPACT CRATERS IN INDIA A THESIS SUBMITTED TO THE UNIVERSITY OF MUMBAI FOR THE PH. D. (SCIENCE) DEGREE IN PHYSICS Submitted By M. D. ARIF UNDER THE GUIDANCE OF PROF. NATHANI BASAVAIAH INDIAN INSTITUTE OF GEOMAGNETISM PLOT NO. 5, SECTOR 18, NEW PANVEL (W), NAVI MUMBAI-410 218 MAHARASHTRA, INDIA APRIL 2013 STATEMENT BY THE CANDIDATE As required by the University Ordinances 770, I wish to state that the work embodied in this thesis titled “Rock Magnetism and Palaeomagnetism of Meteorite Impact Craters in India" forms my own contribution to the research work carried out under the guidance of Prof. Nathani Basavaiah at the Indian Institute of Geomagnetism, New Panvel, Navi Mumbai. This work has not been submitted for any other degree of this or any other University. Wherever references have been made to previous works of others, it has been clearly indicated as such and included in the Bibliography. Signature of Candidate Full Name: Md. Arif Certified by Signature of Guide Name: Prof. Nathani Basavaiah ii Statement required under 0.770 Statement No. 1 I hereby declare that the work described in the thesis has not been submitted previously to this or any other University for Ph. D. or any other degree. Statement required under 0.771 Statement No.2 “Whether the work is based on the discovery of new facts by the candidate or of new relations of facts observed by others, and how the work tends to the general advancement of knowledge.” This thesis introduces a new method for the observation, evaluation and interpretation of the obliquity impact at Lonar based on structural and anisotropy of magnetic susceptibility (AMS) evidence. Impact stress changes are determined using AMS and rock magnetic characteristics. Palaeomagnetic properties are used to determine whether the target basalt was experienced by the meteoritic impact, by which stress-dependent magnetic field directions and rock magnetic parameters are evaluated. For the first time, the thesis introduces shock-induced magnetic effects, which can be evaluated as a natural geomagnetic stress sensor to Indian asteroid impact craters. The rock magnetic and palaeomagnetic techniques have been applied to obtain data from the investigating areas of Indian asteroid impact craters of Lonar and Ramgarh. The important findings are: (1) obliquity impact with impactor hitting the pre-impact target basalts from the east direction at Lonar as evidenced from structural and AMS studies, (2) variations in rock and mineral magnetic properties of Lonar basalts with the E-W plane of impact and direction of impact, (3) determination of SRM, impact-generated plasma fields and mean palaeomagnetic pole positions, (4) geochemical variations in Lonar impact rocks, and (5) rock magnetic properties of Ramgarh target rocks to confirm the impact evidence. This thesis has contributed to the knowledge of the magnetic, mineralogical and structural inventory of impact craters in the Indian shield. It is expected that the results will find use and application in monitoring stress dislocation around impact crater sites, in iii remote sensing studies of impact craters and in Global Positioning System to monitor stress accumulation at active seismic zones. The use of rock magnetic, mineral magnetic and palaeomagnetic methods as indicators for impact craters is suggested, giving insights into the cratering process and the target subsurface, as well as aiding the structural study of known terrestrial impact crater analogues and the identification of unknown ones like Luna in Gujarat. Statement required under 0.771 Statement No. 3 “The source from which this information has been derived and to the extent to which he has based his work on the work of others, and shall indicate which portion or portions of his thesis he claims as original.” The information mentioned is derived by the candidate during the course of research reported in the thesis. The results of the publications are genuine, original and have been published as the following peer reviewed research papers. Papers published in peer reviewed Journals (1) Md. Arif, N. Basavaiah, S. Misra, and K. Deenadayalan (2012), Variations in magnetic properties of target basalts with the direction of asteroid impact: Example from Lonar crater, India: Meteoritics & Planetary Science 47, 1305-1323. (2) S. Misra, Md. Arif, N. Basavaiah, P. K. Srivastava, and A. Dube (2010), Structural and anisotropy of magnetic susceptibility (AMS) evidence for oblique impact on terrestrial basalt flows: Lonar crater, India: Geological Society of America Bulletin 122, 563-574. Papers presented at National and International conferences (1) Md. Arif, S. Misra, N. Basavaiah, and H. Newsom (2009), Distribution of impact- induced stress around Lonar crater, India: 72nd Annual Meteoritical Society Meetings, held 13-18 July 2009 in Nancy, France (abstract no.5397). (2) Md. Arif, S. Misra, and N. Basavaiah (2010), Rock magnetic characterization of target basalts at Lonar crater, India: 41st Lunar and Planetary Science Conference, held March 1-5, 2010 in The Woodlands, Texas. LPI Contribution No. 1533, p. 1571. (3) Md. Arif, K. Deenadayalan, N. Basaviah, and S. Misra (2011), Variation of primary magnetization of basaltic target rocks due do asteroid impact: example from Lonar iv crater, India: 42nd Lunar and Planetary Science Conference, held March 7-11, 2011 in The Woodlands, Texas. LPI Contribution No. 1383. (4) Md. Arif, N. Basavaiah, S. Misra, and K. Deenadayalan (2011), Asteroid impact variations of NRM and REM of target basalts of Lonar crater, India: 74th Annual Meteoritical Society Meeting, held 08-12 August 2011 in London, UK (abstract no.5248). (5) Md. Arif, N. Basavaiah, and S. Misra (2012), Rock- and palaeomagnetic properties of randomly oriented basaltic blocks from Lonar crater ejecta, India: European Planetary Science Congress (EPSC), held 23-28 September 2012 in Madrid, Spain (abstract: EPSC2012-163). Statement required under 0.771 Statement No. 4 “Where a candidate presents joint work, he shall clearly state the portion which is his own contribution as distinguished from the portion contributed by his collaborators.” All field work in the collection of rock samples in Lonar and Ramgarh impact craters, laboratory measurements, data analysis and interpretation were performed by the candidate under the supervision and assistance of the supervisor, Prof. Nathani Basavaiah. Saumitra Misra (Durban, South Africa) assisted in the interpretation of geological inputs and structural results of Lonar and Ramgarh craters. K. Deenadayalan (IIG) assisted in field work in Lonar and Ramgarh craters. P.K. Srivastava (ISRO, Hyderabad) provided the ASTER image of Lonar crater. A. Dube (Kolkata) contributed in structural data analysis of Lonar crater. H. Newsom (New Mexico, USA) helped in conference presentations. This thesis was funded by the in-house IIG project, Environmental Magnetism. (Prof. Nathani Basavaiah) (Md. Arif) Guiding Teacher Candidate v ACKNOWLEDGEMENTS I wish to express my deepest sense of gratitude and profound thanks to my supervisor Prof. Nathani Basavaiah, Head, Environmental Magnetism Laboratory, IIG, for his inspiring guidance, constant encouragement, and patiently supporting me with his knowledge and experience during the entire span of my doctoral research. He cultivated my curiosity, sharpened my thinking and inspired me to become a successful future researcher. I am fortunate to having been associated with him here in the institute. Besides introducing me to the field of Impact Cratering on Indian Shield and formulating the research problem, the laboratory facilities and collaborations he established over the years have helped me enormously. I owe my sincere appreciation to Saumitra Misra for his participation in field trips to Lonar and Ramgarh impact craters, when he was a PDF under my supervisor and for his dedicated involvement in the published research papers with our group members. I wish to thank all my group members K. Deenadayalan, K.V.V. Satyanarayana, B.V. Lakshmi, P.B. Gawali, J.L.V. Mahesh Babu and Dupinder Singh for their kind help rendered in field trips to crater sites, for maintaining a cheerful atmosphere in the laboratory for generating good data, swapping data sets among us and for patiently going through the draft versions of my thesis chapters; often exchanging ideas to fix problems that used to come across in laboratory equipments. Thanks are due to Prof. S.K. Arora of BARC, Mumbai for providing many comments and suggestions. Also unsaid blessings and homely support of Madamji Mrs. Nathani Koteswari to whom I sought suggestions and advices before submitting research related tasks. It’s now my pleasure to thank my dear friends Mahesh Narayan Srivastava, Ajeet Kumar Maurya, Devanandan S. and R. Selvakumaran who made my stay in IIG hostel pleasant and provided friendly atmosphere. I also wish to thank all other research scholars of IIG for helping me directly or indirectly during the tenure of my Ph.D. I would like to thank my parents and family members without whom I would not have achieved this goal. It is the constant sacrifice and ceaseless encouragements of my parents that made it possible for me to realize my goals and dreams. This work would not have been feasible but for the keen interest, love, affection, and unflinching support from them. vi Finally thanks to the Almighty Creator ‘ALLAH’ without HIS blessings this would not be happened. It is HIS will that I would be able to successfully complete it. This thesis is my humble offering to HIM because anything that I am, I believe it is all part of a plan which has already been made for me. Last but not least, I cannot express by words to thank my dear friend and my contemporary colleague Prasanta Kumar Das for sharing everything and he is invaluable source of encouragement at different stages of my career at IIG beginning from joining in the same group and selecting laboratory experimental research. Md. Arif Navi Mumbai, April 2013.