H2O and CO2 in kimberlitic fluid as recorded by diamonds and olivines in several Ekati Diamond Mine kimberlites,Northwest Territories,Canada |
| |
| Authors: | Yana Fedortchouk Sergei Matveev Jon A Carlson |
| |
| Institution: | 1. Géosciences Montpellier, Université Montpellier 2 & CNRS, CC 60, Place E. Bataillon, 34095 Montpellier cedex 5, France;2. Department of Geology, University of Maryland, College Park, MD 20742, USA;1. State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210046, China;2. Institute for Geosciences, University of Frankfurt, Frankfurt am Main 60438, Germany;3. School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;4. SINOPEC Geophysical Research Institute, Nanjing 211103, China;1. Department of Earth and Ocean Sciences, University of South Carolina, 701 Sumter Street, EWS 617, Columbia, SC 29208, USA;2. Jacobs, NASA Johnson Space Center, Mail Code KR, Houston, TX 77058, USA;1. V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia;2. Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia;3. Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52f, 6020 Innsbruck, Austria;4. A.P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, ul. Favorskogo 1a, Irkutsk, 664033, Russia |
| |
| Abstract: | Surface dissolution features on diamonds and Fourier Transform Infra Red spectroscopy (FTIR) of phenocrystal and xenocrystal olivines from kimberlites contain a record of magmatic fluid in kimberlite magmas. We investigated composition and behavior of kimberlitic fluid and the effect of volatiles on the eruption style and geology of kimberlites using microdiamonds and olivine concentrates from six kimberlite pipes with different lithologies and the character of diamond resorption (Ekati Diamond Mine, Northwest Territories, Canada). The study showed a clear correlation between the resorption style of diamond population of the kimberlites and the type of infrared (IR) spectra of their olivines. Four kimberlites have high quality diamonds with smooth regular surface features and high H2O content of the olivines indicating the presence of H2O-rich fluid during the emplacement. Fast ascent rates of fluid-rich magma can explain explosive eruption and filling the pipes with volcaniclastic kimberlite facies. Conversely, Grizzly and Leslie kimberlites have diamonds with complex sharp features diminishing diamond quality and indicating loss of the fluid. The slower ascent rates and less explosive eruption of the fluid-free magmas produced kimberlite pipes filled with magmatic facies kimberlite. Distinctive peaks in olivine IR spectra at 3356 and 3327 cm? 1 were found to correlate with the presence of hydrous magmatic fluid. Character of diamond morphology suggests that during the whole ascent of all six kimberlites, the magmatic fluid when present had a high H2O:CO2 ratio. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
