Formation pathways of oriented magnetite micro-inclusions in plagioclase from oceanic gabbro
نویسندگان
چکیده
Abstract Plagioclase hosted needle- and lath-shaped magnetite micro-inclusions from oceanic gabbro dredged at the mid-Atlantic ridge 13° 01–02? N, 44° 52? W were investigated to constrain their formation pathway. Their genesis is discussed in light of petrography, mineral chemistry, new data transmission electron microscopy (TEM). The show systematic crystallographic shape orientation relationships with plagioclase host. Direct TEM observation selected area diffraction (SAED) confirm that relations are due alignment important oxygen layers between host, a hypothesis made earlier based on backscatter data. Precipitation Fe-bearing plagioclase, which became supersaturated respect interaction reducing fluid, inferred be most likely This process probably occurred without supply Fe an external source but required out-diffusion facilitate partial reduction ferric iron originally contained plagioclase. contain oriented lamellae ilmenite, abundance, size indicate high-temperature exsolution Ti-rich constraining precipitation temperatures excess ~ 600 °C. above Curie temperature magnetite, magnetic signature magnetite-bearing grains must, therefore, considered as thermoremanent magnetization.
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ژورنال
عنوان ژورنال: Contributions to Mineralogy and Petrology
سال: 2021
ISSN: ['1432-0967', '0010-7999']
DOI: https://doi.org/10.1007/s00410-021-01864-8