....7071907 * Correspondence: [email protected] Scientific editing by Scott Wood 14 12 2023 01 02 2024 02 02 2024 Fig. 1. Location of drill holes 004, 005 and 020, and the extent of duricrust mineralization at the Grimlock prospect, Northern Territory, Australia...

... tubules (tu) de matériel jaunâtre plus argileux. Les cavités sphériques autour de clastes et les fractures les contournant suggèrent une dessiccation. Outcrops, macroscopic aspects of the iron-rich duricrusts. A: morphology of the hills shielded at the top by a maximum of 5 m of ferruginous formation...

.... There are no recognized Proterozoic or younger units in the immediate vicinity of the Mount Narryer and Jack Hills metasedimentary belts other than sporadic remnants of a once more extensive Cenozoic silcrete/laterite duricrust ( Fig. 2A ). The nearest source for Paleoproterozoic zircons is the Capricorn orogen adjacent...

... were carried out on gold grains from the Minvoul area (Archean greenstone belt in Gabon). Large grains of almost pure gold were found throughout a weathering profile, which consisted of saprolite, mottled clay zone, iron duricrust, pisolitic gravels and yellow latosol. In the deeper horizons, gold...

..., whereas the Graauwduinen East orebody comprises a largely unrelated dune deposit. Superimposed onto the ore-bearing sequence is a pseudostratigraphy of duricrust that effectively cemented the bulk of the mineralized sands to various degrees of hardness. The two orebodies are profoundly different in many...

... environments. Attention is drawn in this article to three near-surface features (duricrusts, palaeolakes and sulphate-rich soils) that reflect changing environmental conditions and that are of potential significance to engineering investigation, design and construction. Fig. 1. Desert stone pavement, SE...

... oxidation are not soft at all but form duricrusts, such as the canga of Brazil. Others are found along unconformities that represent long-vanished paleosurfaces; an example is the Sishen deposit of South Africa, which formed via oxidation of a large, deformed iron formation on a karstic surface over 2...

...) and overcomes potential pH effects. Improvements in the spatial and amplitude (signal to noise) resolution of this technique compared to total digestion or more aggressive partial digestions is useful not only in areas with exotic cover, but in residual and weathered terrain where duricrust development...

... land surface. The ancient hard hematite orebodies comprise laminated hematite ores in which microplaty hematite is dominant, and massive ores composed almost entirely of martite. Supergene ores, in contrast, are comprised of goethite-rich duricrust and soft saprolitic hematite ores representing...

...) could not be chronologically constrained by means of Sr isotopes and, hence, its age remains conjectural. Aeolian sediments, duricrust and prominent karst relief in the Qatari reference section suggest that the uppermost Dam Formation correlates to the lowermost Shuwaihat Formation in the UAE, where...

... in deeply weathered terrain. It can be used to test geophysical targets in areas with a preserved lateritic mantle and to explore for pipes that may have obscure geophysical signatures. Orientation studies, using ferruginous gravels and duricrust formed on alkaline ultramafic and ultramafic rocks, show...

... thick. The regolith consists of 50 m-thick saprolite, which is clay-rich in the top 10 m, plasmic and mottled clays, lateritic residuum (duricrusts and gravels) and pisolitic soils; the surficial horizons contain pedogenic carbonates. Elements occurring with primary Au mineralization are S, Ag, W...

... of various ages. Four general types are recognized: ferruginous duricrust and gravel, ferruginous mottles, ferruginous saprolite and iron segregations. Ferruginous duricrusts include lateritic residuum and ferricrete. Lateritic residuum has evolved by partial collapse of mottled or ferruginous regolith...

...M. E. Marker; M. J. McFarlane Abstract Deeply weathered saprolite beneath duricrusts is diagnostic of the African surface. Detailed cartographic analysis, supported by field investigation, has been applied to the African surface residuals located between Albertinia and Mossel Bay in the southern...