|
|||||
|
|
Petrochemistry of crater facies Tokapal kimberlite pipe, Bastar craton, central India and its orangeitic affinities |
|
| Authors: | P S Dhote Ashish N Dongre D V Subbarao |
| Institution: | 1. Geological Survey of India, Gandhinagar, 382 043, India 2. Post Graduate Department of Geology, Institute of Science, Aurangabad, 431 004, India 3. CSIR-National Geophysical Research Institute, Hyderabad, 500 606, India |
| Abstract: | Tokapal kimberlite is the only well preserved crater facies kimberlite intruded within sedimentary sequence of Indravati basin in Bastar craton of central India. We present detailed petrographical and whole rock geochemical studies, carried out on ten samples collected from different locations from Tokapal kimberlite to constrain its genesis and also the mantle processes involved in the origin of this earlier characterized Group I kimberlite. Geochemical studies show that only SiO2 content and the mobile trace elements Ba, Sr, and K vary in the crater facies while rest others show restricted range and can be successfully used in evaluating the petrogenetic processes. Very low abundances of Rb (<2 ppm), Sr (<28 ppm), Ba (<52 ppm) and Cs (0.02–3 ppm) are observed which show possible effects of late-stage alteration rather than significant crustal contamination. The LREE enriched REE pattern, absence of positive Eu anomalies and HREE depletion also provide further additional evidence against crustal contamination considerably modifying magma composition. We infer the presence of less enriched (metasomatised) mantle source regions and comparatively greater degrees of partial melting responsible for the genesis of Tokapal kimberlite. Present study also suggests that crater facies Tokapal kimberlite intruding the Indravati basin, Bastar craton has a Group II kimberlite (orangeite) affinity. This finding is important in light of recent identification of Mainpur kimberlites of Bastar craton as orangeites. |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ | |