期刊
MINERALOGICAL MAGAZINE
卷 80, 期 2, 页码 291-310出版社
MINERALOGICAL SOC
DOI: 10.1180/minmag.2016.080.001
关键词
tellurate; tellurite; crystal structure; paragenetic sequence; complexity; secondary minerals; Otto Mountain; California
类别
资金
- Ian Potter Foundation grant 'tracking tellurium'
- Northern California Mineralogical Association
- John Jago Trelawney Endowment to the Mineral Sciences Department of the Natural History Museum of Los Angeles County
An unusually diverse array of 25 secondary Te oxysalt minerals has been documented from Otto Mountain, California, and 18 of these from the Bird Nest drift sublocality. A paragenetic sequence for these minerals is proposed, using observed overgrowth relationships plus spatial association data and data from other localities. Apart from Te and O, the components Pb, Cu and H are essential in the majority of the minerals. The atomic Cu/Te ratio decreases through the paragenetic sequence. This, and the occurrence of minerals with additional components such as Cl-, CO32-, SO42- and Fe3+ at an intermediate stage, suggests non-monotonic evolution of the parent fluids, reflecting differing access to or spatial distribution of various components. For the minerals with known crystal structures, two alternative 'structural units' were identified, one consisting only of the Te4+ or Te6+ oxyanion, while the other also included small, strongly-bound cations such as Cu2+. The degree of polymerization for the Te oxyanion correlated with the paragenetic sequence: the monomeric tellurate anions of early minerals were replaced progressively by dimers, chains and sheet structures, which may relate to a decreasing abundance of the 'network modifying' Cu2+ cation, analogous to Bowen's discontinuous reaction series in igneous rock-forming silicates. No relationship was seen between paragenetic order and the larger type of structural unit, or structural complexity as defined by information content. This contrasts with results in the literature for evaporite sulfates and pegmatite phosphates. While structure-paragenesis relationships may be widespread, the exact nature of such relationships may be different for different chemical systems and different paragenetic environments.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据