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Abstract

The giant stratiform Zn-Pb-Ag HYC deposit displays a broad Zn, Pb and Tl halo which extends laterally along
the favourable pyritic black shale facies of the Barney Creek Formation for at least 15 krn west of the deposit. A
ferroan dolomite/ankerite halo overlaps with the Zn-Pb-Tl halo extending up to 250 m into the immediate stratigraphic
hangingwaD, and 50 to 100 m into the footwall sediments close to the deposit. A manganese carbonate halo is offset from
the ferroan dolomite/ankerite halo, being concentrated in the immediate footwall of the deposit and extending laterally
along the W-Fold Shale Member. Manganiferous carbonate forms the most pronoW1ced and laterally extensive halo at RYC
extending well beyond the Zn-Pb-TI and ankerite halos. The geometry and extent of the halos described above are based
on sampling and analyses from two drill holes repolted in this study and a further six drill holes reported previously by
I.B. Lambert and K.M. Scott [1. Geochem. Explor. 2, 307-330, 1973]. The SEDEX alteration index previously proposed
as a vector for the Lady Loretta deposit [R.R. Large and P.I. McGoldrick, 1998, I. Geochem. Explor. 63, 37-56] has
been shown to have applications in the McArthur Basin for defining the favourable stratigraphic unit hosting stratiform
Zn-Pb-Ag mineralisation. A modified alteration index (AI Mark 3) has also been developed which eliminates the effect
of the shale/dolomite ratio on the index and thus highlights the control of carbonate chemistry and its relationship to
stratiform mineralisation. The application of a group of indices including Zn, Pb, Tl, SEDEX alteration index, AI Mark 3
and manganese content of dolomite (MnOd) is proposed for defining the most favourable stratigraphic units for stratiform
Zn-Pb-Ag mineralisation within carbonate-bearing sedimentary basins. © 2000 Elsevier Science B.Y. All rights reserved.

Item Type:	Article
Authors/Creators:	Large, RR and Bull, SW and McGoldrick, PJ
Keywords:	Sedex zinc-leas, alteration index, AIMark3, manganese, Thalium, ankarite halo
Journal or Publication Title:	Journal of Geochemical Exploration
ISSN:	0375-6742
DOI / ID Number:	https://doi.org/10.1016/S0375-6742(99)00084-9
Additional Information:	The definitive version is available at http://www.sciencedirect.com
Item Statistics:	View statistics for this item

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