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Discovered in 2017 in Algeria, NWA 11273 is a beautiful Lunar meteorite, a feldspathic regolith breccia from the lunar highlands. It consists of the usual menagerie of mineral clasts mixed with rare basalt and glass fragments, all smashed together, as is common on the lunar surface.

These rocks consist of abundant white clasts of anorthositic rock and minor dark clasts of highland basalts, combined with various mineral and glass fragments, and mixed with a dark matrix of solidified rock powder formed under high pressures. This regolith also contains traces of meteoritic material from many impactors bombarding the lunar surface, as well as characteristic amounts of solar wind-implanted noble gases (unshielded by any atmosphere).

This particular meteorite has been the subject of extensive analysis by X-ray fluorescence and Raman spectroscopy (discovering silicates, phosphates and sulphates) and backscattered electron (BSE) and scanning transmission electron microscopy (STEM) which made a novel discovery regarding lunar geology and fluid flows beneath the lunar surface:

“the newly observed olivine veinlets in NWA 11273 are likely formed by secondary deposition from a lunar fluid, rather than by crystallization from a high-temperature silicate melt. Such fluid could be sulfur- and phosphorous-poor and likely had an endogenic origin on the Moon. The new occurrence of secondary olivine veinlets in breccia NWA 11273 reveals that the fluid mobility and deposition could be a previously underappreciated geological process on the Moon.”

Imaging study examples and a map of likely meteorite origin are below in the comments, as well as a diagram of the sub-surface fluid flow hypothesis.

One response to “Understanding the Moon by its Missionaries — NWA 11273”

  1. jurvetson Avatar
    jurvetson

    the cut face, full size and back side of end cutSource of this meteorite in cyan (mostly on far side of the moon), full size"Compositional constraints of likely launch regions of NWA 11273 using the Lunar Prospector FeO and Th data sets. The cyan areas are compositional similar regoliths to the composition of NWA 11273. Locations of the Apollo and Luna sample return missions are noted, along with the Chang’e-3/Chang’e-4 lander and rover landing site. The map highlights with dashed outlines the main geochemical terranes defined"

    Fe-Mn contents in olivine of clasts V1-V5 (orange squares), compared with the lithic clasts and matrix (gray circles) and Apollo samples (open circles):Backscattered electron (BSE) images of the olivine veinlet-bearing lithic clasts in NWA 11273:b) A large (up to 2 mm in length) olivine veinlet cutting across the clast V1.
    c) A close-up showing the detailed texture of clast V1.
    e) Olivine veinlets infill the pyroxene fracture in clast V2. The mineral phases are labeled:
    Opx = orthopyroxene, Cpx = clinopyroxene, Ol = olivine, Pl = plagioclase, Chr = chromite, Tro = troilite.

    More BSE images: b) The olivine veinlets cutting through the clast V3 which exhibits exsolution clinopyroxene lamellae. d) The equilibrated pyroxene fragment (clast V4) contains olivine veinlets. f) A pyroxene fragment (clast V5) containing olivine veinlets:
    Scanning Transmission Electron MIcroscopy (STEM) image of secondary olivine veinlet in clast V5, with close-up view of the contact shown.
    Ol = olivine and Px = pyroxene Cartoon illustrating the highland origin of NWA 11273 and the formation history of olivine veinlet-bearing clasts within basaltic magmas:

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