Petrology and geochemistry of feldspathic impact-melt breccia Abar al' Uj 012, the first lunar meteorite from Saudi Arabia

Mészáros, Marianna; Hofmann, Beda; Lanari, Pierre; Korotev, Randy L.; Gnos, Edwin; Greber, Nicolas; Leya, Ingo; Greenwood, Richard C.; Jull, A. J. Timothy; Al-Wagdani, Khalid; Mahjoub, Ayman; Al-Solami, Abdulaziz A.; Habibullah, Siddiq N. (2016). Petrology and geochemistry of feldspathic impact-melt breccia Abar al' Uj 012, the first lunar meteorite from Saudi Arabia. Meteoritics & planetary science, 51(10), pp. 1830-1848. Meteoritical Society at the University of Arkansas, Dept. of Chemistry and Biochemistry 10.1111/maps.12693

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Abar al' Uj (AaU) 012 is a clast-rich, vesicular impact-melt (IM) breccia, composed of lithic and mineral clasts set in a very fine-grained and well-crystallized matrix. It is a typical feldspathic lunar meteorite, most likely originating from the lunar farside. Bulk composition (31.0 wt% Al2O3, 3.85wt% FeO) is close to the mean of feldspathic lunar meteorites and Apollo FAN-suite rocks. The low concentration of incompatible trace elements (0.39ppmTh, 0.13ppm U) reflects the absence of a significant KREEP component. Plagioclase is highly anorthitic with a mean of An(96.9)Ab(3.0)Or(0.1). Bulk rock Mg# is 63 and molar FeO/MnO is 76. The terrestrial age of the meteorite is 33.4 +/- 5.2kyr. AaU 012 contains a similar to 1.4x1.5mm(2) exotic clast different from the lithic clast population which is dominated by clasts of anorthosite breccias. Bulk composition and presence of relatively large vesicles indicate that the clast was most probably formed by an impact into a precursor having nonmare igneous origin most likely related to the rare alkali-suite rocks. The IM clast is mainly composed of clinopyroxenes, contains a significant amount of cristobalite (9.0 vol%), and has a microcrystalline mesostasis. Although the clast shows similarities in texture and modal mineral abundances with some Apollo pigeonite basalts, it has lower FeO and higher SiO2 than any mare basalt. It also has higher FeO and lower Al2O3 than rocks from the FAN- or Mg-suite. Its lower Mg# (59) compared to Mg-suite rocks also excludes a relationship with these types of lunar material.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences

UniBE Contributor:

Mészáros, Marianna; Hofmann, Beda; Lanari, Pierre; Greber, Nicolas and Leya, Ingo

Subjects:

500 Science > 550 Earth sciences & geology
500 Science > 520 Astronomy
600 Technology > 620 Engineering
500 Science > 530 Physics

ISSN:

1086-9379

Publisher:

Meteoritical Society at the University of Arkansas, Dept. of Chemistry and Biochemistry

Language:

English

Submitter:

Katharina Weyeneth-Moser

Date Deposited:

09 May 2017 13:40

Last Modified:

18 Jun 2019 08:11

Publisher DOI:

10.1111/maps.12693

BORIS DOI:

10.7892/boris.98085

URI:

https://boris.unibe.ch/id/eprint/98085

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