CRC LEME
Open File Report 110
ABSTRACT
Geochemical exploration in areas of transported overburden, Yilgarn
Craton and environs - Murchison Field Trip
Butt, C.R.M., Robertson, I.D.M., Anand, R.R., King, J.D., Munday,
T.J., Phang, C and Smith, R.E.
AMIRA Project 409, Geochemical exploration in areas of transported
overburden, Yilgarn Craton and environs, has, as its principal objective,
the development of geochemical exploration methods for areas having
a substantial cover of surficial sediments, through investigations
of the processes of geochemical dispersion from concealed mineralization.
An important aspect of the project is to translate research findings
into practical outcomes. Field excursions have a significant role
in this process, for they permit geologists and geochemists from
the research group and the supporting companies to examine key sites
together. This interaction promotes a much freer exchange of ideas
than is possible in the formal atmosphere of seminars. The project
has several important research sites and districts across the Yilgarn
Craton. It is impractical to visit all of these at once, hence there
will be at least two excursions during the course of the final year
of the project. This, the first excursion, examines sites in the
Murchison and adjacent areas: their wide separation necessitates
extensive travel. The locations are shown on Figure 1. All are characterized
by the development of red-brown hardpan in the surface horizons.
Pedogenic carbonates are also present at Mt. Gibson and, in places,
Mt. Magnet, but are generally absent from the other sites. The first
visit is to the Mt. Gibson gold mine. This has not, in fact, been
studied during this project, but it was an important site for Project
240, Yilgarn Lateritic Environments, and serves as an excellent
introduction to many of the important features of the regolith and
to the value of regolith-landform mapping. Transported overburden
is a feature of the district, so that many of the findings at Mt.
Gibson are of direct relevance to the objectives of the present
project. The second series of visits is to locations in the Boogardie
Synform in the Mt. Magnet district, including the Quasar and Stellar
gold deposits, the subjects of detailed regolith mapping and geochemical
orientation. Several different regolith-landform settings will be
examined, including near-complete and truncated residual profiles
overlain by colluvial and palaeochannel sediments. On the third
day, the excursion will visit the Harmony deposit at Baxter, near
Peak Hill. This is a new development, mining having commenced in
July, and provides a first opportunity for close inspection of the
regolith at this location. The excursion will demonstrate the regional
landform setting of the deposit and examine the regolith as exposed
in the new pit and as seen in drill core and drill cuttings. Finally,
there will be a brief visit to the Fender deposit, about 2 km south
of the Big Bell mine, near Cue. Mining was due to commence in July
but, unfortunately, this has been delayed and it is now improbable
that the anticipated exposure of the upper regolith will have occurred.
The site is important, because it appears to be completely blind,
even though the cover is thin and, in places, directly overlies
ore-grade mineralization. The visit will examine the setting of
the deposit and inspect samples of the regolith in core and cuttings.
Last updated: Sunday, August 05, 2001 14:08:12
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