Multi-Media Geochemical Exploration in the Critical Zone: A Case Study over the Prairie and Wolf Zn–Pb Deposits, Capricorn Orogen, Western Australia

Round 1

Reviewer 1 Report

The research reported in your manuscript is sound and good and provides interesting information on the expression of different metals in different sample media over fault controlled mineralisation. You have used existing (some previously published) data from a regional scale together with new data over the two deposits to ascertain the different metal uptake by two vegetation species as well as compared the effectiveness of the different geochemical mediums in highlighting the obscured deposits. I found the results interesting especially the expression of different metals in different media – Zn in soil, Ag in Mulga and Pb in spinifex, and also along the fault.

The manuscript is well written, clear and figures appropriate with sufficient information provided in the supplementary material. The interpretation and discussions were also appropriate and accordingly as such I don’t recommend any specific changes, only few comments and in one case a minor recommendation. You seem to emphasis “novel” data collection and results, when in reality all the geochemical media you use have been used since the past 50 years (your references acknowledge these), including use of specific plants (spinifex) and even Fe-Mn crusts (although not as crusts but minerals in soils), and reporting of several different media in one article is also not new – CSIRO AMIRA projects of the reported much of these that too in transported cover (vegetation, soil, groundwater).

The second comment with a recommendation is that you do not mention much if nothing about the nature of the regolith or critical zone i.e. is there a residual profile or transported cover over the deposit. I presume it is residual as Spinks et al (2017) paper does not mention it either. Your final figure alludes to a residual profile. This is critical, because you emphasise the judicious use of sample media in geochemical surveys in areas of transported cover and how your results may assist in areas of cover, but report information from a profile with no transported cover. This is not an issue per se because your data is interesting and valuable, but so that a reader is not left in doubt, could you please clearly mention in your background section or beginning of your results that the critical zone profile is residual although the mineralisation is at depth. In fact, I would be concerned if no geochemical expression showed in the surface media! Metal leakage along faults has been known for years and expounded in a text book by Rose et al (1979), so that result is not new. But therein lies one of the strengths of your research reported in this manuscript and you provided a very good discussion on it – the geochemical expression or “leakages” along fault lines with different metal expressions manifested in different media at the surface or near surface (groundwater). These faults are common and even if they are buried by recent cover, may provide pathways of metal transfer from deeper deposits.

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Reviewer 2 Report

Totally the present article is well-established and the subject is interesting, and minor revision should be considered for publication.

The methods for data analysis, such as the theory of boxplot, the theory of methods for outliers identification, should be introduced in Section 2.

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Reviewer 3 Report

This paper deals with the application of mineral exploration using (bio)geochemical analyses on the Prairie-Wolf deposit areas. Authors present vast amounts of data obtained from plants, Fe-Mn crust, and groundwater. Then, they conclude groundwater and vegetation geochemistry is useful for regional and local mineral exploration. The manuscript is well written in a scientific manner although I wonder what the interpretation in this paper is correct. The analytical data of this paper resulted from the interaction among hydrosphere, lithosphere, and biosphere. That is, the cause of the high concentration of target elements may be much more complex than the paper suggests. However, the mechanism should be beyond the theme of this paper, and further study is necessary as the Authors wrote. Thus, I recommend this paper be published in Minerals after minor revision.

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