![]() |
||
|
Oxygen isotope composition of primitive achondrites (SNCs shown for comparison). Data for brachinites, winonaites, acapulcoite-lodranite clan from Greenwood et al. (2012). Data for ureilites from Clayton and Mayeda (1999). Data for Martian meteorites (SNCs) from Franchi et al. (1999) and compiled from laser fluorination analyses in the Meteoritical Bulletin. Δ17O calculated as: Δ17O = δ17O – 0.52δ18O. Individual winonaite and acapulcoite-lodranite clan samples are very highly susceptible to terrestrial weathering resulting in large shifts in δ18O and to a lesser extent Δ17O. Most analysis points for these two groups plotted on this diagram have been cleaned in EATG (ethanolamine thioglycollate) in order to reduce the influence of terrestrial weathering (see Greenwood et al., 2012 for further details). TFL: terrestrial fractionation line, Y&R: slope 1 line (Young and Russell, 1998), CCAM: carbonaceous chondrite anhydrous mineral line (Clayton et al., 1977; Clayton and Mayeda 1999). |
δ18O | δ17O | Δ17O: given | Δ17O: linear | Comment |
---|---|---|---|---|
3.5700 | 0.7900 | -1.0700 | -1.066 |
Name | Class | δ18O | δ17O | Δ17O: calc | Δ δ18O | Δ δ17O | Δ Δ17O |
---|---|---|---|---|---|---|---|
Northwest Africa 8685 | Acapulcoite | 3.5360 | 0.7590 | -1.08 | -0.03 | -0.03 | -0.01 |
Northwest Africa 12437 | Acapulcoite/Lodranite | 3.6180 | 0.8460 | -1.035 | 0.05 | 0.06 | 0.03 |
Northwest Africa 6704 | Achondrite-ung | 3.6130 | 0.8800 | -0.999 | 0.04 | 0.09 | 0.07 |
Northwest Africa 12437 | Acapulcoite/Lodranite | 3.6900 | 0.8920 | -1.027 | 0.12 | 0.1 | 0.04 |
Northwest Africa 4529 | Lodranite | 3.4670 | 0.9390 | -0.864 | -0.1 | 0.15 | 0.2 |
Northwest Africa 10132 | Achondrite-ung | 3.7890 | 0.8570 | -1.113 | 0.22 | 0.07 | -0.05 |
Northwest Africa 7674 | Lodranite | 3.4880 | 1.0040 | -0.81 | -0.08 | 0.21 | 0.26 |
Hassi el Biod 002 | Pallasite, ungrouped | 3.3860 | 0.6500 | -1.111 | -0.18 | -0.14 | -0.04 |
Northwest Africa 10074 | Acapulcoite | 3.6910 | 0.9910 | -0.928 | 0.12 | 0.2 | 0.14 |
Northwest Africa 12437 | Acapulcoite/Lodranite | 3.7690 | 0.9210 | -1.039 | 0.2 | 0.13 | 0.03 |
Northwest Africa 4448 | Lodranite | 3.5510 | 0.5390 | -1.308 | -0.02 | -0.25 | -0.24 |
Northwest Africa 10074 | Acapulcoite | 3.7240 | 1.0210 | -0.915 | 0.15 | 0.23 | 0.15 |
Northwest Africa 10132 | Achondrite-ung | 3.8320 | 0.8930 | -1.1 | 0.26 | 0.1 | -0.03 |
Northwest Africa 7674 | Lodranite | 3.2810 | 0.7640 | -0.942 | -0.29 | -0.03 | 0.12 |
Northwest Africa 8685 | Acapulcoite | 3.8410 | 0.8980 | -1.099 | 0.27 | 0.11 | -0.03 |
Néma 001 | Achondrite-ung | 3.2570 | 0.6240 | -1.07 | -0.31 | -0.17 | -0 |
Northwest Africa 2775 | Acapulcoite | 3.2500 | 0.9700 | -0.72 | -0.32 | 0.18 | 0.35 |
Northwest Africa 4448 | Lodranite | 3.4130 | 0.4420 | -1.333 | -0.16 | -0.35 | -0.27 |
Northwest Africa 4529 | Lodranite | 3.1890 | 0.7570 | -0.901 | -0.38 | -0.03 | 0.17 |
Hassi el Biod 002 | Pallasite, ungrouped | 3.3900 | 0.4400 | -1.323 | -0.18 | -0.35 | -0.26 |
Northwest Africa 4529 | Lodranite | 3.1680 | 0.8290 | -0.818 | -0.4 | 0.04 | 0.25 |
Northwest Africa 6704 | Achondrite-ung | 3.9220 | 1.0150 | -1.024 | 0.35 | 0.23 | 0.04 |
Northwest Africa 5782 | Acapulcoite/lodranite | 3.2400 | 0.5300 | -1.155 | -0.33 | -0.26 | -0.09 |
Dhofar 125 | Acapulcoite | 3.5700 | 0.3600 | -1.496 | 0 | -0.43 | -0.43 |
Northwest Africa 8685 | Acapulcoite | 3.9320 | 1.0250 | -1.02 | 0.36 | 0.24 | 0.05 |
Northwest Africa 8287 | Acapulcoite | 3.2000 | 0.5000 | -1.164 | -0.37 | -0.29 | -0.1 |
Northwest Africa 2210 | CH3 | 3.9500 | 1.0700 | -0.984 | 0.38 | 0.28 | 0.08 |
Northwest Africa 6592 | Lodranite | 3.9800 | 1.0400 | -1.03 | 0.41 | 0.25 | 0.04 |
Northwest Africa 12455 | CR7 | 3.6370 | 0.2960 | -1.595 | 0.07 | -0.49 | -0.53 |