Magister Scientiae - MSc / In areas of transported overburden there is frequently a weak relationship between soil and the underlying mineralized bedrock. Vegetation has the capability to absorb metals from the underlying substrate via its extensive root systems. These metals are translocated to the various organs of the plant such as leaves, twigs bark and roots without negatively impacting on the normal functioning of the plant. The analysis of the vegetation may therefore be used to locate deeply buried mineral targets. The main focus of this investigation was to determine the suitability of A. karroo and B. albitrunca for biogeochemical prospecting for gold in the Blue Dot Mine area. The appraisal of the suitability for both plant species requires an understanding of element absorption and distribution patterns in relation to variable composition of bedrock and associated underlying gold mineralization. / South Africa

In areas of transported overburden there is frequently a weak relationship between soil and the underlying mineralized bedrock. Vegetation has the capability to absorb metals from the underlying substrate via its extensive root systems. These metals are translocated to the various organs of the plant such as leaves, twigs bark and roots without negatively impacting on the normal functioning of the plant. The analysis of the vegetation may therefore be used to locate deeply buried mineral targets. The main focus of this investigation was to determine the suitability of A. karroo and B. albitrunca for biogeochemical prospecting for gold in the Blue Dot Mine area. The appraisal of the suitability for both plant species requires an understanding of element absorption and distribution patterns in relation to variable composition of bedrock and associated underlying gold mineralization.

In areas of transported overburden there is frequently a weak relationship between soil and the underlying mineralized bedrock. Vegetation has the capability to absorb metals from the underlying substrate via its extensive root systems. These metals are translocated to the various organs of the plant such as leaves, twigs bark and roots without negatively impacting on the normal functioning of the plant. The analysis of the vegetation may therefore be used to locate deeply buried mineral targets. The main focus of this investigation was to determine the suitability of A. karroo and B. albitrunca for biogeochemical prospecting for gold in the Blue Dot Mine area. The appraisal of the suitability for both plant species requires an understanding of element absorption and distribution patterns in relation to variable composition of bedrock and associated underlying gold mineralization.

Η παρούσα διατριβή ερευνά τους παράγοντες που συνεπιδρούν στη λειτουργία των οικοσυστημάτων του Όρους Τυμφρηστού. Έτσι αναλύθηκαν το αβιοτικό περιβάλλον (γεωλογία, τοπογραφία, υδρολογία, κλίμα) από τη μια πλευρά και το βιοτικό περιβάλλον (φυτογεωγραφία, βιολογικές μορφές, χλωρίδα, βλάστηση) από την άλλη. Επιπλέον, θεωρώντας ότι ο άνθρωπος είναι ο σημαντικότερος παράγοντας του οικοσυστήματος, μελετήθηκαν όλες εκείνες οι ενέργειες από πλευράς του, που επηρεάζουν και αποτρέπουν τη φυσική εξέλιξη των οικοσυστημάτων και προτείνονται διαχειριστικά μέτρα. / The aim of the present doctorate thesis is to investigate all the elements that affect the functioning of the ecosystem of Mt. Timfristos area. In order to achieve this, the abiotic environment (geology, topology, hydrology, climate) on one hand, and the biotic one (phytogeography, biologic patterns, flora, vegetation) on the other, was analyzed. Seeing that man is the most important element of the ecosystem, all his activities that effect and avert the normal course of ecosystems were studied and proposed measures management.

[Tuncated abstract] Soil is a relatively low cost and robust geochemical sampling medium and is an essential part of most mineral exploration programs. In areas of covered terrain, however, soils are less reliable as a sampling medium because they do not always develop the geochemical signature of the buried mineralisation; possibly a result of limited upward transport of ore related elements into the surficial overburden. As economic demands on the resources industry grow, mineral exploration continues to expand further into areas of covered terrain where the rewards of finding a new deposit relative to the risks of finding it may be comparatively low. Thus, improving the costeffectiveness of a geochemical exploration program requires a sound understanding of the mechanisms by which soil geochemical anomalies form in transported overburden. This thesis examines the deep biotic uplift of ore related elements by deep rooting vegetation as a mechanism for the development of soil geochemical anomalies within transported overburdens, in semi-arid and arid regions. '...' Vegetation and soils were analysed at two Au prospects in Western Australia: Berkley, Coolgardie and Torquata, 210 km south-east of Kambalda, in semi-arid Western Australia to complement both the mass balance and the differential modelling. At Berkley, both the vegetation and soils located directly over the mineralisation showed high concentrations of Au. There may be indirect evidence for the operation of the deep plant uptake flux taking effect from the field evidence at Berkley. Firstly, anomalous concentrations of Au were found in the surface soils, with no detectable Au in the transported overburden. Secondly, the trace element concentrations in vegetation showed correlation to the buried lithology, which to our knowledge has not been reported elsewhere. The results from the samples at Torquata, in contrast, were less conclusive because the Au is almost exclusively associated with a surficial calcrete horizon (at <5 m soil depth). Strong correlations of Ca and Au in leaf samples however, suggest that the vegetation may be involved in the formation of calcrete and the subsequent association of Au with the calcrete. Among the vegetation components, the litter and leaf samples gave the greatest anomaly contrast at both prospects. Finally, three main drivers for the deep biotic uplift of elements were identified based on the results from the mechanistic numerical modelling exercise: i) the deep uptake flux; ii) the maximum plant concentration and; iii) the erosional flux. The relative sizes of these three factors control the rates of formation and decay, and trace element concentrations, of the soil anomaly. The main implication for the use of soils as exploration media in covered terranes is that soil geochemical anomalies may only be transient geological features, forming and dispersing as a result of the relative sizes of the accumulative and loss fluxes. The thesis culminates in the development of the first quantitative, mechanistic model of trace element accumulation in soils by deep biotic uplift.