Mineralization
within
the
Dong Gou porphyry molybdenum deposit, Eastern Qinling
Mountains, Henan, China
Storm,
Lauren,
Friehauf, Kurt,
Yuan,
Zhenlei, Xiao, Ping, and Moorehead, Anthony,
2009,
Mineralization
within
the
Dong
Gou porphyry molybdenum deposit, Eastern Qinling
Mountains, Henan, China [abs]: 2009 Portland GSA Annual Meeting
(18-21 October 2009), Geological Society of America Abstracts with
Programs, Vol. 41, No. 7, p. 84.
Mesoproterozoic
Xiong’er
Group
andesite
hosts Cretaceous molybdenum ores in the Dong
Gou molybdenum deposit in the eastern Qinling Mountains of Henan,
China. Current mining activity is done by hand mucking and hauling high
grade ores from shallow underground workings. Thin, discontinuous
K-feldspar veins characterize earliest mineralization styles, which are
cut by quartz-molybdenum veins associated with hydrothermal biotite
alteration of andesite. Where hairline quartz-molybdenite veins cut
feldspar phenocrysts in the andesite, K-feldspar overgrowths fill the
vein. Quartz-molybdenite veins became thicker, more continuous, and
planar as the system evolved, reflecting cooling and transition to a
more brittle strain environment. Molybdenite-barren, blue
apatite-K-feldspar veins crosscut early quartz-molybdenite and evolved
through time from apatite-dominant to K-feldspar-dominant modes with
minor molybdenum on vein margins. Thick quartz-molybdenite-pyrite veins
that crosscut barren apatite-rich veins record a second stage of
molybdenite mineralization. K-feldspar-chlorite-quartz-pyrite veins
postdate both molybdenite stages.
Early fluorine-rich phases such as fluorite and topaz reported at Dong
Gou by Wei et al. (2009) were not exposed at mine levels examined in
this study, suggesting fluorine in this part of the deposit may be
locked up in apatite veins.
The Dong Gou deposit represents an important variation on the
extension-related, high-fluorine-type molybdenite deposits in the
eastern Qinling metallogenic belt.
