2005 Fiscal Year Final Research Report Summary
An experimental study of reproduction of nakhlite martian meteorites
| Project/Area Number |
15540463
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | National Institute of Polar Research |
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Principal Investigator |
IMAE Naoya National Institute of Polar Research, Research Associate, 研究教育系, 助手 (60271037)
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| Project Period (FY) |
2003 – 2005
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| Keywords | nakhlite / Martian meteorite / experimental petrology / magma / phase equilibrium / cummulates / parent magma / crystallization sequence |
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| Research Abstract |
During the research period for three years, I carried out the followings.
(1)I studied two different nakhlites of the Yamato nakhlites and MIL 03346, estimated these parent magma compositions based on the mass balance calculation, and determined the crystallization sequences for these melts. These series of studies were presented by several domestic and international meetings of mineralogical and meteoritical societies, and a full paper has been published in an international journal of Meteoritics and Planetary Science.
(2)I set up the vertical gas-mixing furnace at 1 bar. Using this furnace, I have been carrying out isothermal experiments in order to determine and revise the phase relationship for nakhlite magmas and cooling experiments for the synthesis of nakhlites under the QFM condition. When two years passed since I started experiments, I found that the stainless was contaminated into glass during the preparation of the starting material, we used agate mortar instead of stainless m
… More
ortar for the glass crushing. As results, I modified the preliminary experimental results. Then the liquidus temperatue of a possible parent magma for nakhlites is 1140℃, and titanomagnetites and augites co-crystallize. The solidus temperature is 〜980℃.
(3)Experiments using the parent magma composition, which I determined based on the mass balance calculation, showed that compositions of crystallized augites are closely identical with those in core augites in nakhlites. This strongly suggests that the parent magma composition is correct. Closely similar texture and composition to the MIL 03346 nakhlite produced from a cooling experiment of 4.2℃/h. Rim augites surrounding phenocrystic core augites in nakhlites are generally divided into two types : the Yamato type with Ga-poor pyroxene outer rim and the MIL type of hedenburgitic outer rim. I synthesized these two types : rims of Yamato type formed from slow cooling runs mainly at 1℃/h and those of MIL type from rapid cooling runs mainly at 4.2℃/h.
I will continue to carry out experiments till this summer, and will submit a full paper to an international journal. Less
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