Discussion Comments on: “Trace element and isotopic evidence for Archean basement in the Lonar crater impact breccia, Deccan volcanic province” by Ramananda Chakrabarti and Asish R. Basu in Earth and Planetary Science Letters 247 (2006) 197–211 Saumitra Misra ⁎ CSM project on Lonar Crater (SRIC), Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur-721 302, India Received 4 August 2006; accepted 22 August 2006 Available online 14 September 2006 Editor: R.W. Carlson We extend our hearty thanks to Chakrabarti and Basu [1] for their sincere effort in generating high quality trace element and Rb–Sr, Sm–Nd and Pb–Pb isotopic data of the target-basalt and impact breccia samples from Lonar impact crater, India. Their effort deserved special merit because isotopic data on Lonar samples is perhaps generated for the first time in the history of Lonar Crater research. Their observation of the possible incorporation of Archean basement in the Lonar impact breccia provides an interesting possible twist on the basement target for this crater. The authors have intro- duced this concept only to explain significant enrich- ment of Rb, Ba, Th and Pb, high 87 Sr/ 86 Sr and 207 Pb/ 204 Pb isotopic ratios and negative ε Nd of their Lonar impact breccia samples over target-basalt as observed in their analyses. Although it is an excellent effort on analytical geo- chemistry, the part which the readers cannot know from this paper, are the details of the samples that were the basis of this research. As I provided the samples for this work as mentioned in their paper, there are some important aspects of the samples that can clarify the interpretations of their data. I gave samples to the authors from my January 2001 field collections which included four (4) target-basalt samples collected from fresh upper 50 m of the crater's wall, two (2) genuine in situ impact-melt samples that belong to type ‘c’ impactites of Osae et al. [2] collected from within the ejecta blanket outside the crater [2], and five (5) non-in situ impact-looking melts of unknown status from in and outside the crater that belong to type ‘d’ and ‘e’ impactites of Osae et al. [2]. As I had limited analytical facilities in my capacity in our country at that time, I have had to collaborate with many international colleagues (C. Koeberl, H. Newsom, A. R. Basu, and R. Chakrabarti) for the generation of best quality geochem- ical and isotopic data on Lonar samples. The non-in situ impact breccia samples that were analyzed by Chakrabarti and Basu [1] are of doubtful origin, a fact that we clearly mentioned in our early paper [2] and none of them can be matched with the description of impact-melts of Kieffer et al. [3] that were produced in different stages of shock metamorphism. These samples are mostly opaque under microscope, heterogeneous, highly vesicular, and contain abundant fragments of plagioclase, clinopyroxene and basalt that are unshocked and show no preferred orientation, and petrographically Earth and Planetary Science Letters 250 (2006) 667 – 668 www.elsevier.com/locate/epsl DOI of original article: 10.1016/j.epsl.2006.05.003. ⁎ Tel.: +91 3222 283380; fax: +91 3222 277190. E-mail addresses: saumitra_misra@yahoo.co.uk, saumitramisra@hotmail.com. 0012-821X/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.epsl.2006.08.018