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The Discovery of Magnesioferrite from Au (Fe, Cu) Magnesian Skarn Deposits and Study of the Magnesioferrite‐Magnesiomagnetite Series
Author(s) -
Yiming ZHAO,
Yinan ZHANG,
Chengsi BI,
Lihe GUO
Publication year - 1998
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.1998.tb00416.x
Subject(s) - skarn , metasomatism , mineral , mineralogy , geology , geochemistry , calcite , materials science , metallurgy , fluid inclusions , seismology , mantle (geology) , hydrothermal circulation
Magnesioferrite, a rare metasomatic mineral, was discovered for the first time in China from the Qinlou Au (Fe, Cu) magnesian skarn deposit, Sanpu, Huaibei, Auhui Province, and the Mulonggou Fe (Mo, Cu) magnesian skarn deposit, Luonan County, Shaanxi Province. In this paper, the geological setting, mineral associations, chemical composition, some physical properties, X‐ray powder diffraction data and infrared spectroscopy of magnesioferrite and magnesiomagnetite are discussed. Magnesioferrite contains 17.66%–13.48% of MgO. Its main associated minerals are clinohumite, chondrodite, serpentine, calcite and magnesiomagnetite. The density of magnesioferrite is 4.537–4.720, reflectances in percent are: 17.8–18.1, hardness is 838–900 kg/mm 2 , and the cell parameter a o = 8.371–8.379 Å. A systematic study of the magnesioferrite‐magnesiomagnetite‐magnetite series suggests that along with the increase of magnesioferrite molecules in the mineral, the density, reflectances and cell parameters decrease correspondingly, the hardness heightens, and the infrared absorption spectral band becomes wider. The authors consider that magnesioferrite is a product of contact metasomatism between hypabyssal intermediate‐acid intrusions and dolomitic marble. It was formed in shallow exocontact zones under relatively oxidized conditions.