Massive sulfide deposits and volcanism

Economic Geology



Massive sulfide deposits, consisting of pyrite and/or pyrrhotite and various ratios of chalcopyrite, sphalerite, and galena, are commonly associated with volcanic rocks that accumulated in eugeosynclines. Later deformation may leave an imprint of regional metamorphism. Two-thirds of the deposits mentioned in this review are about equally divided between silicic and mafic volcanic host rocks, and the remainder occur in tuffaceous sedimentary rocks interbedded with volcanics.

Little compelling evidence is available to relate genetically most of these deposits to granitic rocks, whereas considerable evidence supports a complex genetic relationship to volcanic rocks that accumulated in a submarine environment. Some deposits apparently formed during or soon after emplacement of the volcanic rocks, and possibly involved early deposition of pyrite that was followed later by the addition of base metals.

The transporting agents of the base metals and some of the sulfur are heated solutions probably of different origins containing alkali chlorides as well as alkali chloride brines. Pyrite and base metals may have been deposited during the accumulation of the volcanic and associated rocks, or later during diagenesis, regional metamorphism, or intrusion of granitic plutons. The source of the base metals may have been: (1) early metal concentrations distributed through the volcanic pile, (2) trace quantities in the silicate minerals in the volcanics, or (3) later crystallizing magma.

Publication type Article
Publication Subtype Journal Article
Title Massive sulfide deposits and volcanism
Series title Economic Geology
DOI 10.2113/gsecongeo.64.2.129
Volume 64
Issue 2
Year Published 1969
Language English
Publisher Society of Economic Geologists, Inc.
Description 18 p.
First page 129
Last page 146
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