SHERGOTTITES (3 subclasses) |
1. ENRICHED SUITE (shallowest source region; variable compositions) |
a. mafic, more evolved (e.g. Dhofar 378 and pairing, JaH 479, Ksar Ghilane 002, Los Angeles, NWA 856, NWA 2800, NWA 2975 and pairings, NWA 3171, NWA 5298, NWA 5718, NWA 6963 (Fej Errih) and pairing, NWA 7257, NWA 7320, NWA 10414 [pig-phyric], Shergotty, Zagami) |
b. permafic, moderately evolved (e.g. NWA 1068 and pairings [poss. near primary mantle melt of intermediate Mg# along with LAR 06319], NWA 4468, NWA 7397, RBT 04261/62) |
c. ultramafic, less evolved (or olivine accumulation) (e.g. ALH 84001) |
2. INTERMEDIATE SUITE (Bulk Mars; variable compositions) |
a. mafic, more evolved (e.g. EETA79001B, NWA 480/1460, NWA 4480 [εHf and εNd indicate unique mantle source plotting between Intermediate and Depleted; Irving et al., 2016, #2330], NWA 5029) |
b. permafic, moderately evolved (e.g. EETA79001A, NWA 1950, NWA 2646, NWA 2990 and pairings, NWA 6234 and pairings [near primary magma melt], NWA 7042, NWA 10169, NWA 11065, NWA 11214, NWA 12241) |
c. ultramafic, less evolved (e.g. ALHA77005 [near primary mantle melt], GRV 99027, GRV 020090, LEW 88516, NWA 4797, NWA 6342, NWA 10697, NWA 10961 [shock veins], NWA 11261, Y-1075, Y-793605, Y-984028 and pairings) |
3. DEPLETED SUITE (deepest source region; variable compositions) |
a. mafic, more evolved (e.g. NWA 7635 [olvplag-phyric; after >43% fractional crystallization of Y98-like magma; most depleted shergottite], NWA 8159 [near primary mantle melt], QUE 94201 [after 43% fractionation]) |
b. permafic, moderately evolved (e.g. DaG 476 and pairings, Dho 019, NWA 1195, NWA 2046, NWA 2626, NWA 4527 and pairing, NWA 4925, NWA 5789 [near primary mantle melt], NWA 5990, NWA 6162, NWA 7032 and pairing, SaU 005 and pairings, Tissint, Y-980459 and pairing [ol-websterite; near primary mantle melt]) |
c. ultramafic, less evolved (e.g. NWA 13179 [olivine microwebsterite; photo courtesy of Ben Hoefnagels]) |
Trace Elements | Redox | 147Sm/144Nd | ε182W | ε142Nd | 180Hf/183W | |
---|---|---|---|---|---|---|
Depleted Mantle Reservoir 1 |
LREE Depleted (shergottites DaG 476, QUE 94201, SaU 005, Y-980459) |
reduced (IWIW+1) |
≥0.285 | ≥0.6 | ≥0.9 | ≥18 |
Depleted Mantle Reservoir 2 |
LREE Depleted (nakhlites) |
oxidized (≥IW+3.5) |
~0.2550.266 | ~2.95 | ~0.74 | ~2243 |
Depleted Mantle Reservoir 3 |
LREE Undepleted (orthopyroxenite ALH 84001) |
reduced (IWIW+1) |
~0.214 | ~0.49 | ~0.19 | ~19 |
Enriched Mantle Reservoir |
LREE Enriched (shergottites Los Angeles, NWA 1068, Shergotty, Zagami) |
oxidized (>IW+2) |
<0.182 | ≤0.3 | ≤0.2 | ≤11 |
⇒ INCREASING SILICATE FRACTIONATION ⇒ | ||
---|---|---|
olivine-phyric (34.5 wt% Al) | low-Al basalt (34.5 wt% Al) | high-Al basalt (56.5 wt% Al) |
*NWA 1068 (enriched) | Zagami (enriched) | *Los Angeles (enriched) |
Y-980459 (depleted) | Shergotty (enriched) | QUE 94201 (depleted) |
LAR 06319(enriched) | NWA 856 (enriched) | Dhofar 378 (enriched) |
NWA 6234 (intermediate) | NWA 480/1460 (intermediate) | EETA79001B (intermediate) |
EETA79001A (intermediate) | NWA 5298 (enriched) | Ksar Ghilane 002 (enriched) |
Dag 476/489 (depleted) | ||
SaU 005 (depleted) | ||
Tissint (depleted) | ||
NWA 5789 (depleted) |