TANG Ping-zhi1, 2, WANG Yu-wang2, WANG Jing-bin2, LONG Lingli2, ZHANG Hui-qiong2, LIAO Zhen2
(1. Faculty of Land Resource Engineering, Kunming University of Science and technology, Kunming 650093, China;
2. Beijing Institute of Geology for Mineral Resources, Beijing 100012, China)
Abstract: Ilvaite, an uncommon type of skarn typomorphic mineral, was first found in Cihai iron deposit. In this study geological occurrence, mineral association, chemical composition and optical property of ilvaite in Cihai area were discussed. The mineral chemical composition by EPMA showed that the molecular formula of the Cihai ilvaite is Ca0.98(Fe1.72Mn0.07Mg0.11)1.902+(Fe0.95Al0.03) 0.983+[Si2.00O7]O(OH), which belonging to normal ilvaite species. It is considered that the ilvaite was related with mafic subvolcanic rocks and with the hydrothermal metallogeny as a kind of typical retrograde, postskarn mineral. At the end of mineralization, the early skarn minerals can be metasomated and substituted by ilvaite. Ilvaite of the Cihai deposit was formed in later mineralization stage and had a dilution effect to the early magnetite. It is suggested that ilvaite is a kind of important mineral in mineralogy and should be paid more attention.
Key words: ilvaite; skarn; diabase; Cihai iron deposit
E-mail: Tangpingzhi 710@126.com
ACTA MINERALOGICA SINICA Vol. 31, No. 1, 2011, Page 9-16
