DaG 647 - rare type of eucrite ( 2-stage thermal history! )

One completely fresh and perfectly oriented eucrite with outstanding flow lines in its black fusion crust was found in winter 1996/97.

When some meteorite expert looks at Dar al gani 647 he first might assume seeing a sample.of a planetary meteorite (shergottite) (crystal features suggest heritage from a bigger parent body) and not an eucrite.

DAG 647 according to Dr.Hiroshi Takeda et al is a unique type of a recrystallized monomict eucrite with two(!) separate phases of thermal history ! DaG 647 isvery unusual in appearance - you would be very surprised by its unique texture! Weight : 1425g Note:DaG 647 is not paired with DaG 567. DaG 567 is a nice little eucrite (TKW:22g) and it was found in the same major region - but that's already nearly all they have in common. DaG647 has experienced a 2 stage thermal history, DaG 567 does not . DaG 647 has an extremely low value of magnetic susceptibility - falling in the range of most lunar meteorites. DaG647 is a unique eucrite and not paired to DaG 567 or other known eucrites. Already the makroscopic texture looks completely different from any other known eucrite .(ask for macroscopic and thincut images ) . DaG 647:  The pyroxene and plagioclase in the matrix are recrystallized to a fine-grained granoblastic crystalline texture which masks the original fragmental texture commonly observed in other monomict eucrites. Dusty pyroxene crystals caused by the presence of chromite and ilmenite are similar to those found in other monomict eucrites and were probably present before the recrystallization phase. This is not the case at DaG 567 .A rare silica mineral has also been identified in DaG 647 which also is not the case in DaG 567.  Major basaltic lithology : plagioclase with sub-rounded smaller grains of pyroxene .The plagioclase and the pyroxene in the matrix are recrystallized to a granoblastic crystalline texture which masks the original fragmental structure normally observed in monomict eucrites . The sizes of the major pyroxene crystals in crystalline parts are larger than those of lath-shaped plagioclase crystals. Large laths of plagioclase are remained in the fine grained recrystallized areas . The boundaries between the fragmented matrices and large crystalline clasts are difficult to identify because of the apparent crystalline texture. Small pigeonite grains and ilmenite show subrounded shape . A rare silica (!) mineral has also been observed . Themesostasis areas are also recrystallized to fine-grained granoblastic pyroxene and tear-shaped ilmenite. TiO2 concentrations of the spinel grains vary from 12.8to 17.3 wt. %. Small ranges of Ti compositions in DAG may suggest some equilibration. This is in contrast to those in Ibitira and EET which have wider ranges of chemical compositions. The pyroxene grains show fine exsolution lamellae and thin twin bands, but "clouding" known for ordinary eucrites are mostly erased and are remained only in the core of a few large crystals. The plagioclase compositions are fairly uniform (An85 to An89 , mean: An88 ) for the lath-shaped texture. Shock texture after recrystallization has not been observed. This meteorite can best be described as a "recrystallized monomict eucrite" (H.Takeda et al). This eucrite is of highest scientific value due to its unique thermal history !!

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