Table 1 Main properties of impact spherules from Antarctica.

SR, spinel-rich; SP, spinel-poor; BO, barred olivine; CC, cryptocrystalline; DM, glassy dominated by dendritic magnesioferrite.

SampleLocalityCoordinatesAge (ka ago)TypesSize (μm)Shape
WNWalnumfjellet72°07’S, 24°12′E<870SR, SP, BO, and CC93 to 473Spherical +
subspherical
L1*Dome Concordia75°06′S, 123°21′E434SR and SPUp to 100 μmAngular (SP) +
spherical (SR)
DF2641Dome Fuji77°19′S, 39°42′E434 ± 6SR and SPUp to 100 s μmSubspherical
L2*Dome Concordia75°06′S, 123°21′E481DMSubmicrometer:
25 μm
Spherical
DF2691Dome Fuji77°19′S, 39°42′E481 ± 6DMSubmicrometer:
15 μm
Spherical
MBMiller Butte72°42′S, 160°14′E481Mainly DMSubmicrometer:
65 μm
Spherical
BIT-58§Allan Hills76°43′S, 159°40′E2.8 × 103SR, SP, BO, and DMUp to 100 μmAngular (SP) +
spherical (SR)
SampleMineralogySpinel
morphology
Olivine
morphology
Fa (olivine)δ18O (‰)
WNOlivine + glass +
Fe spinel
Cruciform +
dendritic + cubic
Porphyritic +
skeletal + barred
7 to 69−51 to −32
L1*Olivine + glass +
Fe spinel
Cruciform +
dendritic
Porphyritic +
skeletal
~10 to 50−38 to −21ǁ
DF2641Olivine + glass +
Fe spinel
Cruciform +
dendritic
Porphyritic +
skeletal + barred
26 to 85−47 to −27
L2*Glass + Fe spinelDendritic−17 to −10ǁ
DF2691Olivine + glass +
Fe spinel
DendriticDendritic~10 to 50
MBOlivine + glass +
Fe spinel
Cruciform +
dendritic + cubic
Skeletal + barred14 to 213 to 6
BIT-58§Olivine + glass +
Fe spinel + Fe metal
Cruciform +
dendritic + cubic
Porphyritic +
skeletal + barred
17 to 24

References: *(8),

†(9),

‡(7),

§(24),

ǁ(48).