Mineralogy and Petrology of New Antarctic Shergottite QUE94201: A Coarse-Grained Basalt With Unusual Pyroxene Zoning
QUE94201 is a new Antarctic shergottite. Although its mineralogy is similar to previously known basaltic shergottites, QUE94201 (QUE) has distinct differences from them. QUE has larger grain sizes and contain abundant maskelynite, whitlockite and a wide impact melt vein enriched in P. The coarse-grained texture of pyroxene and maskelynite is similar to lunar meteorite Asuka881757. The largest difference of QUE from typical shergottites is pyroxene zoning trends which are very similar to pyroxenes of Apollo lunar mare basalts such as 12021. However, the low FeO/MnO ratio of pyroxene and existence of Na-rich maskelynite distinguish QUE from lunar basalts. Cooling rate calculations of pigeonite rim zoning constrain the cooling rate to be faster than 5 degrees C/yr (Burial depth: <30 m). This indicates the last stage of crystallization would occur in a shallow lava flow.
Lunar and Planetary Science Conference
- Pub Date:
- March 1996
- BASALT: MARE;
- COOLING RATES;
- ZONING: CHEMICAL