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Название: Proceedings of the 24th international applied geochemistry symposium, volume 2
Авторы: Lentz D., Thorne K., Beal K.
Аннотация:
Concentrations for 53 elements in till (C-horizon sediment) sampled over the Mount
Fronsac North volcanogenic massive sulfide deposit were analyzed to determine whether geochemical
concentrations were coincident with known glacial flow directions, and whether Hg could be used as a
pathfinder element for massive sulfides. Based on data from these analysis, three patterns were
observed in glacial till: palimpsest (Pb, Ag and Cu), related to local ice flow dispersal of mineralized
gossan; ribbon (Ni, Co and Cr), related to flow of the Laurentide Ice Sheet over gabbroic intrusions and
an arcuate pattern (Hg and Cd) related to post-glacial ionic mobility. Concentration gains of Mo, As, Sb
and Hg in supergene gossan and gains of Zn, Au, Cd, Hg and Co in till were calculated using Sn as a
conservative element. These results indicate that processes responsible for element signatures in till
over the Mount Fronsac North deposit are: 1) pre-glacial weathering of primary sulfides resulting in
gossan formation, 2) pre-glacial colluvial and hydromorphic redistribution of gossanous material, 3) west
to east and southwest to northeast mechanical transport of mineralized bedrock by glaciers and 4) ionic
migration of cations and anions due to electrochemical reactions between wall rock and sulfides.