Five years ago we took a general look at DaG 1040 and last March the subject was its metal content. Recently I got to look at two new thin sections of this meteorite and I am intrigued again by its variety of features and textures.
The first five photos below survey the striking difference between two neighboring barred chondrules. Their proportions are similar but their sizes are quite different, especially the apparent thicknesses of their bars.
This is a view in crossed polarized light of an eight millimeter wide portion of a thin section of DaG 1040, a somewhat odd CV3 meteorite. The left side was ground and polished a bit thinner than the standard thickness. The two gray clouds at the top are CAI, calcium-aluminum rich inclusions. We will take a closer look at two barred chondrules seen here. At the lower right is a large red, orange and blue BO chondrule, a component of a larger feature. A much smaller white barred chondrule is attached to some bright red grains a little below the left CAI.
This is that white BO chondrule up close. This view is only 0.4 mm wide. DaG 1040 CV3 xpl.
The other, the colorful BO chondrule, is much larger and shows well in this 3.1 mm wide view. DaG 1040 CV3 xpl.
The left interior of the larger BO chondrule at the same scale as the close-up of the white one. Field of view is 0.4mm wide. DaG 1040 CV3 xpl.
Side by side. Bars are very different.
Chondrule with a delicate, fine grained rim. FOV=1.5mm. DaG 1040 CV3 xpl.
Chondrule rimmed with large olivine crystals. FOV=3.1mm. DaG 1040 CV3 xpl.
Deformed (crashed?) chondrule containing metal and other opaques. Note brown rust staining. FOV=3.1mm. DaG 1040 CV3 oblique incident light.
Same chondrule in xpl.
FOV=3.1mm. DaG 1040 CV3 xpl.
Several chondrules with glass-clear (though crystalline) mineral grains. FOV=3.1mm. DaG 1040 CV3 xpl.
Closer. FOV=0.8mm. DaG 1040 CV3 xpl.
The perfect polish on the thin section makes these views possible.