ISSN:
1365-3091
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Geosciences
Notes:
This paper presents the main trends in epigenetic research in the U.S.S.R. in the last years:〈list xml:id="l1" style="custom"〉1Study of epigenetic zonality in thick series of sedimentary rocks of various ages and tectonic regions, (zones of unaltered clay matrix, of altered clay matrix, of quartzitic structures and hydromica-chloritic cement, and of prick-like structures and phyllite-like schists).2Principles of stadial analysis and mineral indicators of different epigenetic stages (clay minerals, organic matter, zeolites, feldspars, sulfides).3Facies of regional epigenesis connecting the main petrographic families of unaltered terrigenic rocks (quartz sandstones with kaolinitic matrix and the same composition of associated clays, acidic arkoses with hydromicaceous clays, lithoclastic sands with several matrix components and associated clays, and volcanogenic greywackes) with “related” facies of regional metamorphism.4Some practical aspects of epigenesis are: for petroleum geology: maximum depth of burial according to porosity, interruption of quartz, feldspar, sphene, epidote, carbonate, biotite, and clay mineral epigenesis by oil migration; and for ore geology: (a) initial epigenesis: ore impregnation (e.g., volkonskoite in wood remains) due to intrastratal solution of heavy minerals and leaching of rock fragments; (b) deep epigenesis: e.g., galena impregnations due to release of trace elements during dissolution of rock forming minerals e.g., feldspars; and (c) metagenesis: “Alpine” veins across and along bedding, filled, e.g., with copper ores.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-3091.1970.tb00203.x
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