ALBERT

Description / Table of Contents: Weathering Processes --- M. J. Wilson and D. Jones: Lichen weathering of minerals: implications for pedogenesis / Geological Society, London, Special Publications, 11:5-12, doi:10.1144/GSL.SP.1983.011.01.01 --- D. A. Spears: Porewater reactions in the unsaturated zone with special reference to groundwater quality in England / Geological Society, London, Special Publications, 11:13-18, doi:10.1144/GSL.SP.1983.011.01.02 --- David C. Cawsey and Paul Mellon: A review of experimental weathering of basic igneous rocks / Geological Society, London, Special Publications, 11:19-24, doi:10.1144/GSL.SP.1983.011.01.03 --- Kaolinites, Laterites and Bauxites --- H. Wopfner: Kaolinisation and the formation of silicified wood on late Jurassic Gondwana surfaces / Geological Society, London, Special Publications, 11:27-31, doi:10.1144/GSL.SP.1983.011.01.04 --- J. Esteoule-Choux: Kaolinitic weathering profiles in Brittany: genesis and economic importance / Geological Society, London, Special Publications, 11:33-38, doi:10.1144/GSL.SP.1983.011.01.05 --- A. Vincent: The origin and occurrence of Devon Ball Clays / Geological Society, London, Special Publications, 11:39-45, doi:10.1144/GSL.SP.1983.011.01.06 --- S. K. Monro, F. C. Loughnan, and M. C. Walker: The Ayrshire Bauxitic Clay: an allochthonous deposit? / Geological Society, London, Special Publications, 11:47-58, doi:10.1144/GSL.SP.1983.011.01.07 --- T. R. Marshall, B. J. Amos, and D. Stephenson: Base metal concentrations in kaolinised and silicified lavas of the Central Burma volcanics / Geological Society, London, Special Publications, 11:59-68, doi:10.1144/GSL.SP.1983.011.01.08 --- M. J. McFarlane: A low level laterite profile from Uganda and its relevance to the question of parent material influence on the chemical composition of laterites / Geological Society, London, Special Publications, 11:69-76, doi:10.1144/GSL.SP.1983.011.01.09 --- Ida Valeton: Palaeoenvironment of lateritic bauxites with vertical and lateral differentiation / Geological Society, London, Special Publications, 11:77-90, doi:10.1144/GSL.SP.1983.011.01.10 --- J. Esson: Geochemistry of a nickeliferous laterite profile, Liberdade, Brazil / Geological Society, London, Special Publications, 11:91-99, doi:10.1144/GSL.SP.1983.011.01.11 --- Red Beds --- R. Gardner: Reddening of tropical coastal dune sands / Geological Society, London, Special Publications, 11:103-115, doi:10.1144/GSL.SP.1983.011.01.12 --- K. Pye: Post-depositional reddening of late Quaternary coastal dune sands, north-eastern Australia / Geological Society, London, Special Publications, 11:117-129, doi:10.1144/GSL.SP.1983.011.01.13 --- B. M. Besly and P. Turner: Origin of red beds in a moist tropical climate (Etruria Formation, Upper Carboniferous, UK) / Geological Society, London, Special Publications, 11:131-147, doi:10.1144/GSL.SP.1983.011.01.14 --- Duricrusts: Calcretes, Silcretes and Gypcretes --- H. Wopfner: Environment of silcrete formation: a comparison of examples from Australia and the Cologne Embayment, West Germany / Geological Society, London, Special Publications, 11:151-158, doi:10.1144/GSL.SP.1983.011.01.15 --- W. J. E. van de Graaff: Silcrete in Western Australia: geomorphological settings, textures, structures, and their genetic implications / Geological Society, London, Special Publications, 11:159-166, doi:10.1144/GSL.SP.1983.011.01.16 --- M. A. Summerfield: Geochemistry of weathering profile silcretes, southern Cape Province, South Africa / Geological Society, London, Special Publications, 11:167-178, doi:10.1144/GSL.SP.1983.011.01.17 --- C. C. Reeves, Jr: Pliocene channel calcrete and suspenparallel drainage in West Texas and New Mexico / Geological Society, London, Special Publications, 11:179-183, doi:10.1144/GSL.SP.1983.011.01.18 --- Donald Carlisle: Concentration of uranium and vanadium in calcretes and gypcretes / Geological Society, London, Special Publications, 11:185-195, doi:10.1144/GSL.SP.1983.011.01.19 --- John Parnell: Ancient duricrusts and related rocks in perspective: a contribution from the Old Red Sandstone / Geological Society, London, Special Publications, 11:197-209, doi:10.1144/GSL.SP.1983.011.01.20 --- Colin F. Klappa: A process-response model for the formation of pedogenic calcretes / Geological Society, London, Special Publications, 11:211-220, doi:10.1144/GSL.SP.1983.011.01.21 --- A. S. Talma and F. Netterberg: Stable isotope abundances in calcretes / Geological Society, London, Special Publications, 11:221-233, doi:10.1144/GSL.SP.1983.011.01.22 --- F. Netterberg and J. H. Caiger: A Geotechnical classification of calcretes and other pedocretes / Geological Society, London, Special Publications, 11:235-243, doi:10.1144/GSL.SP.1983.011.01.23 --- R. P. Shaw: Karstic residual fluorite-baryte deposits at two localities in Derbyshire / Geological Society, London, Special Publications, 11:245-249, doi:10.1144/GSL.SP.1983.011.01.24 --- John A. Catt: Cenozoic pedogenesis and landform development in south-east England / Geological Society, London, Special Publications, 11:251-258, doi:10.1144/GSL.SP.1983.011.01.25

Description / Table of Contents: J. Brooks: Introduction / Geological Society, London, Special Publications, 12:ix-xv, doi:10.1144/GSL.SP.1983.012.01.01 --- Geological and Geochemical Studies of Northwest European Continental Shelf --- P. J. Walmsley: The role of the Department of Energy in petroleum exploration of the United Kingdom / Geological Society, London, Special Publications, 12:3-10, doi:10.1144/GSL.SP.1983.012.01.02 --- A. Makourine: Gas Exploration and Reserves in Europe / Geological Society, London, Special Publications, 12:11-17, doi:10.1144/GSL.SP.1983.012.01.03 --- P. C. Barnard and B. S. Cooper: A Review of Geochemical Data Related to the Northwest European Gas Province / Geological Society, London, Special Publications, 12:19-33, doi:10.1144/GSL.SP.1983.012.01.04 --- J. L. Gevirtz, B. D. Carey, and S. R. Blanco: Surface Geochemical Exploration in the North Sea / Geological Society, London, Special Publications, 12:35-50, doi:10.1144/GSL.SP.1983.012.01.05 --- E. Faber and W. Stahl: Analytic Procedure and Results of an Isotope Geochemical Surface Survey in an Area of the British North Sea / Geological Society, London, Special Publications, 12:51-63, doi:10.1144/GSL.SP.1983.012.01.06 --- J. Sigalove: Petroleum Offshore Sniffer Exploration / Geological Society, London, Special Publications, 12:65, doi:10.1144/GSL.SP.1983.012.01.07 --- G. J. Candy: Petroleum Exploration Onshore U.K. / Geological Society, London, Special Publications, 12:67-68, doi:10.1144/GSL.SP.1983.012.01.08 --- T. P. Brennand: North Sea petroleum exploration / Geological Society, London, Special Publications, 12:69, doi:10.1144/GSL.SP.1983.012.01.09 --- Hans Rønnevik, Svein Eggen, and Jan Vollset: Exploration of the Norwegian Shelf / Geological Society, London, Special Publications, 12:71-93, doi:10.1144/GSL.SP.1983.012.01.10 --- D. C. Mudge and G. M. Bliss: Stratigraphy and Sedimentation of the Palaeocene Sands in the Northern North Sea / Geological Society, London, Special Publications, 12:95-111, doi:10.1144/GSL.SP.1983.012.01.11 --- C. D. Curtis: Geochemistry of Porosity Enhancement and Reduction in Clastic Sediments / Geological Society, London, Special Publications, 12:113-125, doi:10.1144/GSL.SP.1983.012.01.12 --- Hilary Irwin and Andrew Hurst: Applications of Geochemistry to Sandstone Reservoir Studies / Geological Society, London, Special Publications, 12:127-146, doi:10.1144/GSL.SP.1983.012.01.13 --- M. J. Pearson and D. Watkins: Organofacies and Early Maturation Effects in Upper Jurassic Sediments From the Inner Moray Firth Basin, North Sea / Geological Society, London, Special Publications, 12:147-160, doi:10.1144/GSL.SP.1983.012.01.14 --- M. J. Pearson, D. Watkins, J-L Pittion, D. Caston, and J. S. Small: Aspects of Burial Diagenesis, Organic Maturation and Palaeothermal History of an Area in the South Viking Graben, North Sea / Geological Society, London, Special Publications, 12:161-173, doi:10.1144/GSL.SP.1983.012.01.15 --- C. Cornford, J. A. Morrow, A. Turrington, J. A. Miles, and J. Brooks: Some Geological Controls on Oil Composition in the U.K. North Sea / Geological Society, London, Special Publications, 12:175-194, doi:10.1144/GSL.SP.1983.012.01.16 --- M. J. Fisher and Jennifer A. Miles: Kerogen Types, Organic Maturation and Hydrocarbon Occurrences in the Moray Firth and South Viking Graben, North Sea Basin / Geological Society, London, Special Publications, 12:195-201, doi:10.1144/GSL.SP.1983.012.01.17 --- R. H. Reitsema: Geochemistry of North and South Brae Areas, North Sea / Geological Society, London, Special Publications, 12:203-212, doi:10.1144/GSL.SP.1983.012.01.18 --- A. E. Griffith: The Search for Petroleum in Northern Ireland / Geological Society, London, Special Publications, 12:213-222, doi:10.1144/GSL.SP.1983.012.01.19 --- D. G. Roberts: Frontier exploration in Western and Northwest Europe / Geological Society, London, Special Publications, 12:223-224, doi:10.1144/GSL.SP.1983.012.01.20 --- Petroleum Exploration of Europe --- L. Mattavelli, T. Ricchiuto, D. Grighani, and M. Schoell: Origins of Natural Gas in the Po Valley, N. Italy / Geological Society, London, Special Publications, 12:227, doi:10.1144/GSL.SP.1983.012.01.21 --- M. Schoell and M. J. Whiticar: Isotope Geochemistry of Natural Gases in Central Europe / Geological Society, London, Special Publications, 12:229, doi:10.1144/GSL.SP.1983.012.01.22 --- K. Kuckelkorn, H. Wehner, and H. Hufnagel: Geochemical Observations and Oil Genesis in the German Alps and their foreland / Geological Society, London, Special Publications, 12:231-233, doi:10.1144/GSL.SP.1983.012.01.23 --- D. P. McKenzie: Basin Evolution and Hydrocarbon Generation / Geological Society, London, Special Publications, 12:253-254, doi:10.1144/GSL.SP.1983.012.01.25 --- B. Durand and M. Paratte: Oil Potential of Coals: A Geochemical Approach / Geological Society, London, Special Publications, 12:255-265, doi:10.1144/GSL.SP.1983.012.01.26 --- P. A. Schenck, J. W. de Leeuw, T. C. Viets, and J. Haverkamp: Pyrolysis-Mass Spectrometry in Coal Chemistry: a study of the coalification of vitrites and the typification of Australian Brown Coals / Geological Society, London, Special Publications, 12:267-274, doi:10.1144/GSL.SP.1983.012.01.27 --- D. J. Batten: Identification of Amorphous Sedimentary Organic Matter by Transmitted Light Microscopy / Geological Society, London, Special Publications, 12:275-287, doi:10.1144/GSL.SP.1983.012.01.28 --- P. M. R. Smith: Spectral Correlation of Spore Coloration Standards / Geological Society, London, Special Publications, 12:289-294, doi:10.1144/GSL.SP.1983.012.01.29 --- J. M. A. Buiskool Toxopeus: Selection Criteria for the Use of Vitrinite Reflectance as a Maturity Tool / Geological Society, London, Special Publications, 12:295-307, doi:10.1144/GSL.SP.1983.012.01.30 --- A. J. G. Barwise: Use of Porphyrins as a Maturity Parameter for Oils and Sediments / Geological Society, London, Special Publications, 12:309-315, doi:10.1144/GSL.SP.1983.012.01.31 --- Petroleum Geochemical Principles and Techniques --- D. H. Welte, M. A. Yükler, M. Radke, D. Leythaeuser, U. Mann, and U. Ritter: Organic Geochemistry and Basin Modelling — Important Tools in Petroleum Exploration / Geological Society, London, Special Publications, 12:237-252, doi:10.1144/GSL.SP.1983.012.01.24 --- Geological Information on Hydrocarbon Exploration on the U.K. Continental Shelf --- G. G. Baxter: Introduction / Geological Society, London, Special Publications, 12:319, doi:10.1144/GSL.SP.1983.012.01.32 --- D. J. McKay: The Compilation of an Earth Science Bibliography for the North Sea and Adjacent Areas / Geological Society, London, Special Publications, 12:321-328, doi:10.1144/GSL.SP.1983.012.01.33 --- P. Wigley: Commercially Available Geological Databanks—U.K.C.S. / Geological Society, London, Special Publications, 12:329-341, doi:10.1144/GSL.SP.1983.012.01.34 --- J. R. V. Brooks: Geological Information from Hydrocarbon Exploration on the United Kingdom Continental Shelf / Geological Society, London, Special Publications, 12:343-356, doi:10.1144/GSL.SP.1983.012.01.35 --- K. J. Chew and H. Stephenson: EXPHST—A Program to Analyse the History of Exploration Success within a Basin or Country / Geological Society, London, Special Publications, 12:357-371, doi:10.1144/GSL.SP.1983.012.01.36 --- G. G. Baxter: The Use of Computerized Information in Britoil, Exploration Division / Geological Society, London, Special Publications, 12:373, doi:10.1144/GSL.SP.1983.012.01.37

Description / Table of Contents: Abstract Granodioritic rocks from the stock of Quellaveco, their surrounding rhyolites and a subvolcanic dyke give K-Ar ages between Paleocene and lower Eocene, with an “mean age” of 53.7 M.Y. These results agree with those of other porphyry-copper deposits in the South-Western USA, in Northern Chile, and, which have been generated during Laramian orogenesis. Furthermore, no significant age difference between the pluton and the basement, have been observed, is interpreted as indicative of a consanguineous origin for both rock types.

Description / Table of Contents: Résumé Les indices manganésifères des collines Blafo et Guéto sont rencontrés dans les quartzites et les schistes sériciteux associés aux épanchements rhyolitiques d'une série volcano-sédimentaire birrimienne. La minéralisation, épigénétique, est une imprégnation d'oxydes de fer (goethite) et de manganèse (essentiellement MnO2-cryptomélane et nsutite), surimposée à une paragénèse initiale à magnétite, pyrophanite et localement ottrélite et grenat. L'altération météorique n'a provoqué de transformations notables que dans les matériaux associés à deux surfaces d'aplanissement. L'une est conservée sous forme de petits témoins bauxitisés au sommet des collines et des minerais enrichis sont associés à la gibbsite et la kaolinite. L'autre est un glacis de piémont et le manganèse s'y disperse dans une cuirasse ferrugineuse.

Description / Table of Contents: Abstract Fluid inclusions in calcites sampled in a Pb-Zn mineralized vein in East Belgium are characterized by a large dispersion of filling temperatures Th (30°C to more than 360°C) and by two groups of freezing points Tf2 (−14°C and −21°C). Boiling has not been proved. According to the still unexplained dispersion of the filling temperatures, this study does not permit an estimation of the depth of the ore formation. Nevertheless, fluid inclusions thermometric properties make possible the distinction between calcites associated with a mineralization (from the fertile locality of Poppelsberg) and calcites from sterile area (Belle Roche, Th=150°C, Tf2 variable around a mode of −8°C).

Description / Table of Contents: Résumé Des minéralisations epigénétiques à plomb-zinc cuivre d'age tertiaire existent dans la couverture carbonatic mesozoïque du Haut-Atlas oriental (Maroc) tandis que les minéralisations à stibine, barytine et cuivre sont localisés dans le socle d'age précambrien à paleozoique. Les mesures du rapport isotopique du carbone dans les roches carbonatées encaissantes varie de +3‰ à -1‰ PDB. Les resultats sont caracteristiques d'un carbone d'origine marine. Il n'y a pas de differences entre les dolomies encaissantes et les veines dolomitiques plus récents. Dans les mêmes échantillons la composition isotopique de l'oxygène est enrichie en isotope O16 (variant de -3‰ à -11‰ PDB) par rapport à cette des carbonates en equilibre avec l'eau de mer. On suppose que la composition isotopique a changé au cours de la minéralisation ces phénomènes étant lié à la migration d'eaux connèes de la formation en partie diluis par des eaux météoriques. On estime que la soufre des sulfures syngénétiques reduits bacteriologiquement et des sulfates marins du Mesozoïque remobilisés durant l'orogénèse tertiaire sont les sources de H2S et SO4. On estime que des sulfates du Cambro-Ordovicien constituent la source pour les gîtes des Jebel Zelmou dans le socle. La composition isotopique du plomb des galènes dans les gîtes tertiaires de la couverture mesozoique est rigoureusement homogéne. Les ages varient de 230 à 180 Ma. On considére que des processus de remobilisation importants sont à l'origine de la metallogénèse tertiaire au Maroc.

Description / Table of Contents: Abstract Microprobe analysis of mineralisations from the district of Hualgayoc, Peru, shows a zonation of sphalerite compositions all around a rhyodacitic body. The differences in the iron content of sphalerites in veins inside the rhyodacite and in sedimentary strata may be explained by a contamination of the hydrothermal solutions by those strata.

Description / Table of Contents: Abstract Since its formation in earliest Cambrian time, the St-Honoré alkaline complex has fractured into large subhorizontal slabs under the effect of magmatic pulsations and thermal contraction. These slabs were rapidly segmented and cracked by the same stresses. The secondary permeability resulting from these fractures first aided the circulation of the rare earth mineralizing hydrothermal fluids in the center of the complex, and then, after the unroofing of the complex, instigated the development of a karstic drainage system within the carbonatites of the complex. The accumulated sediments in the karstic caverns derive from the periodic inwashing of the insoluble residues built up on the surface of erosion, were indurated after the sealing of the karstic openings with calcareous muds during the Ordovician transgression, and were faulted with their cover when the Saguenay graben formed. The last event, marked by low temperature regional mineralizating circulation (barite and calcite crystals coating geodes at NIOBEC), permitted the establishment of a new subterrean drainage system.

Description / Table of Contents: Abstract The sulphur isotope composition of 233 sulphides and 40 sulphates has been investigated and evaluated in combination with 29 earlier published data. The total variation of δ34S values for the sulphides and the sulphates ranges from −40 up to −1 ‰ and from +7 up to +20 ‰, respectively. For the mineral species the variations are (with number of samples in brackets): galena (96) −32 up to −2 ‰, sphalerite (141) −30 up to −4 ‰, marcasite (16) −27 up to −1 ‰, pyrite (10) −26 up to −13 ‰, molybedenite (3) −40 up to −29 ‰, anhydrite and gypsum (8) +15 up to +20 ‰, coelestine (1) +19 ‰, and barite (33) +7 up to +18 ‰. The frequency distribution of the δ34S values corresponds with the complexity of the ore forming processes which resulted in six strata-bound ore mineralizations. The sulphate values clearly show that the sulphate sulphur originates from sea water sulphate. The sulphides are formed by bacteriogeneric processes from seawater sulphate, and their sulphur isotope composition depends on the lithofacies of the sediments as well as on the following diagenetic processes.

Description / Table of Contents: Abstract The main manganese oxides of oceanic nodules: todorokite and birnessite, are considered as regular solutions of MnO2 and MnO. Thermodynamic properties of regular solutions are used for the calculation of Gibbs energies ΔG° of these oxides and of their equilibrium constants of precipitation by oxidation from Mn2+ of sea water. From equilibrium diagram representation it is possible to distinguish the different manganese oxide forms, when looking at Mn2+ activity and pE: Mn2+ variations in sea water originates mainly from hydrothermal springs and diagenetic fluxes, while pE variations reflects the transient states during oxide rehandling. This solid state transformations defines a pE-buffer.

Description / Table of Contents: Résumé De nombreux indices et anciennes exploitations de faible tonnage pour Pb-Zn-Ba-F s'observent dans les séries carbonatées du Dévonien moyen et supérieur du SW du Synclinorium de Dinant où elles délimitent un district métallifère. Une étude lithogéochimique régionale des calcaires givétiens montre le faible potentiel métallifère de ces sédiments de plateforme. Ces résultats sont confirmés par l'étude de la distribution de 13 éléments présents dans un filon et son encaissant immédiat. Enfin la comparaison des compositions isotopiques du Pb des galènes du filon et du Pb en trace dans les calcaires encaissants apporte des arguments décisifs. Ces résultats sont suffisants pour rejeter l'hypothèse de l'origine des métaux par sécrétion latérale et militent en faveur du caractère “épigénétique-étranger” de ces minéralisations.

Description / Table of Contents: Abstract The physico-chemical parameters (pH, Eh, T, conductivity, alkalinity) of thirty one water samples have been measured within the Yeelirrie uraniferous calcrete channel (46000 tons of estimated U3O8). The major element (Ca++, Mg++, Na+, K+, SO 4 -- , Cl-) and some trace element (Cr, Co, Ni, Pb, Ti, Cu, Si, Zn, Ba, Sr, F, V, U) concentrations of nineteen water samples have been also measured. The results of the Wateq program traitment of most of this datas are in general in agreement with the channel mineralogy. Most dissolved elements, and in particular the necessary elements to the ore deposit formation, barring vanadium, are concentrated by a fast maturation waters process in relating to arid climate. In some time, the water pH increase and the Eh decrease. The V4+ is removed dating probable vanadiferous concentrations near the ore body by slightly oxydising waters. The installation of a redox front between a supersaturated ground water upstream a barrier structure and more oxidizing waters penetrating in a primary palustrine limestone provoke the V4+ to V5+ oxidation. The dolomitization of this limestone have for consequence the CO 3 -- ion activity decreasing who induce the decomplexation of uranyle carbonate ions and thus the U6+ supply. Then, the carnotite may precipitate. Thus, the climate, the hydrology and the morphology appear like the controls of Yeelirrie type ore deposit.

Description / Table of Contents: Résumé Les intrusions de rhyolites et de microgranites de la région d'Ain-Barbar (massif de l'Edough — Cap de Fer, Algérie) sont recoupées par des veines à minéralisation polymétallique (Fe-Cu-Zn-Pb) et ont subi des altérations hydrothermales corrélables à cet épisode de métallisation. Leur datation par la méthode K-Ar a été entreprise pour préciser l'âge de cet événement. Les mesures effectuées donnent des “âges” conventionnels compris entre 15 et 16 M.A., avec deux “âges isochrones” à 15.1 et 16.0 M.A. L'âge le plus ancien pourrait correspondre à la mise en place des intrusions microgranitiques, ainsi qu'à celle de l'un des filons rhyolitiques. L'âge le plus jeune, obtenu sur deux autres filons rhyolitiques est à la fois celui de leur mise en place intrusive et des altérations hydrothermales qui les affectent; c'est aussi celui des altérations hydrothermales subies par les intrusions plus anciennes. Ces mesures confirment que le magmatisme du massif de l'Edough — Cap de Fer s'est produit à la fin du Burdigalien et au Langhien, et montrent que les phénomènes hydrothermaux ont suivi immédiatement les épisodes d'intrusion. Elles permettent en outre de préciser l'âge de la dernière phase de plissements importants dans cette région.