Mineralized outcrop

The rate and quantity of radon and uranium contributed to waters exposed to mineralized outcrops and the subsequent mobility of these elements in the present day environment has not been previously documented. This paper presents the results from leaching experiments carried out on uranium-enriched Horton Group sandstones in the Windsor area of Nova Scotia. Understanding of these processes is important both to environmental and exploration geochemistry. 

Thermal expansion induced by insolation may be important in desert areas where rocky outcrops and soil surfaces are barren. In a desert, daily temperature excursions are wide and rocks are heated and cooled rapidly. Each type of mineral in a rock has a different coefficient of thermal expansion. Consequently, when a rock is heated or cooled, its minerals differentially expand and contract, thereby inducing stresses and strains in the rock and causing fractures. Ollier (1969) discussed examples of rock weathering due to insolation. Fire can develop temperatures far in excess of insolation and be quite effective in fracturing rocks (Black-welder, 1927). 

Mineral exploration, the search for economic ore deposits, requires somewhat different reference samples than those used in ore valuation. Soil or sediment and water samples are frequently used in the search when mineralized areas of abundant outcrop or those covered only by thin locally derived overburden are being evaluated. In such cases, it is virtually impossible not to detect the mineralization from an analysis of ore elements in these types of samples. Later, as the mineral deposits closest to the surface were exploited and then played out, new deposits occurred at progressively greater depths, and these sample types were less and less effective as markers in the search (Hoffman 1989). 

Fig. 8.34 Lefty, outcrop rocks found at the crater wall of Eagle Crater, where the rover Opportunity landed on 24 January 2004. Clearly, the sedimentary structure is seen. Right) in the spectrum, taken on sol 33 (sol = Martian day) of the mission, the mineral Jarosite, an Fe -sulfate, could be identified at the Meridiani Planum landing site. It forms only under aqueous conditions at low pH (< 3 ) and is therefore clear mineralogical evidence for aqueous processes on Mars...

A number of sites with anomalous catchment outlet sediment geochemistry are associated with catchments containing known outcropping mineral occurrences, confirming the value of the approach. 

Major elements trends show that Northeastern Mexican beaches are influenced by heavy minerals and plutonic and sedimentary outcrops. 

Gawler Craton, located on the edge of the Great Victoria Desert (GVD). In this part of the GVD, regolith landforms are comprised of scarce hills of weathered bedrock outcrops surrounded by sand spreads, dunes and colluvial materials the hills act as windows to the otherwise covered weathered bedrock. The outcrops themselves have been silicified and, more recently, have been overprinted with calcrete. Calcrete sampling is relatively easy on the exposed outcrops and is preferentially sampled by mineral explorers due to its near-surface location (<10-20 cm depth). However, calcrete on the colluvial slopes and in the swales is not as easily located because of concealment by GVD sand and colluvium. 

Cambro-Ordovician altered meta-rhyolitic pyroclastics are host to the Thalanga Zn, Pb and Cu massive sulfide deposit in Queensland (Govett Atherden 1987). Beyond the sub-outcrop gossan zone mineralization is covered by up to 70 m of Tertiary horizontal terrestrial sandstones, conglomerates and siltstones (Campaspe beds). 

Currently, Uracan Resources Limited owns claims to the Main Double S Zone, as well as two other mineralized zones (Middle Zone and TJ Zone) within the North Shore Property. These three zones combined contain a total inferred resource estimate of 154.9 million tonnes at an average grade of 0.012% UaOs and contain 18.48 million kilograms (40.73 million pounds) of uranium using a 0.009% cut off (Uracan website). These resources outcrop at surface, are open at depth and along strike. 

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