Issue |
E3S Web Conf.
Volume 98, 2019
16th International Symposium on Water-Rock Interaction (WRI-16) and 13th International Symposium on Applied Isotope Geochemistry (1st IAGC International Conference)
|
|
---|---|---|
Article Number | 01050 | |
Number of page(s) | 4 | |
Section | Geological Evolution of Water-Rock System: Mechanisms, Processes, Factors, Stages. The Session Dedicated to Stepan Shvartsev’s Memory | |
DOI | https://doi.org/10.1051/e3sconf/20199801050 | |
Published online | 07 June 2019 |
Water-rock interactions: the formation of an unusual mineral assemblage found in a Siberian coal
1
University of Texas at Dallas, Richardson, TX 75080, USA
2
Tomsk Polytechnic University, Tomsk 634050, Russia
* Corresponding author siarbuzov@mail.ru
Volcanic ash is regularly found in coal and is particularly common in the Minusinsk coal basin in southern Siberia, Russia. Ash deposits in coal are usually observed in the form of thinly bedded, kaolinite-rich layers called tonsteins. The coal we studied by scanning electron microscopy with an energy dispersive detector contained many of the minerals typically found in tonsteins: kaolinite groundmass, volcanogenic phenocrysts such as K-feldspar, quartz, apatite, and zircon, along with secondary minerals such as galena, sphalerite, and REE minerals. However, in addition to these commonly observed minerals, the groundmass contains a rare calcium-bearing magnesian siderite in roughly equal proportion to the kaolinite. Ca-Mg siderite has only been reported in a few Australian coals and never at these relatively high proportions. The relative levels of K-feldspar, apatite, and quartz are consistent with a parent magma of felsic to intermediate composition. The Ca-rich-Mg siderite appears to have developed late in the diagenetic process, likely as a result of the dissolution of calcic feldspars, micas, and mafic minerals in the acidic peat waters releasing calcium, iron, and magnesium which reacted with carbon dioxide from the decomposing plant matter.
© The Authors, published by EDP Sciences, 2019
This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.