No abstract

A case study of sinus histiocytosis of Rosai-Dorfman (SH) clinically limited to the skin is presented with immunohistochemical study of the infiltrate, in both paraffin and cryostat sections. Factor XIIIa, a dendrocyte marker, was demonstrated in the cytoplasm of histiocytes. This feature had not been previously reported in this disease. In addition, the cells expressed S100 protein, CD4, CD1a, CD68, and CD11c. This immunophenotyping study suggests that SH could affect the antigen-presenting activity of Factor XIIIa cells, i.e., the skin dermal dendrocyte.

The basal unit of this flysch sequence consists of about 700 m of rhythmically interlayered red and green claystone intercalated with feldspathic sandstone and lithic conglomerate. Chemical analyses show that both types of claystones have approximately the same Fe2O3 content (8%). The presence within green claystone of inarticulate brachiopods, thin laminations of phosphate and pyrite, coupled with a high Mn content (Fe/Mn : 27) together with the composition of the chlorites, suggest that green mud was deposited slowly in a marine environment under reducing conditions. The hematite content of red claystone averages 4%. The Fe/Mn is high (71), and the clay fraction contains chamosite in addition to chlorite and illite. These characteristics favour a paralic oxidizing environment for the red muds. Rapid resedimentation of red sediment from a paralic environment into the green lithotope, rather than a lateral variation of facies, is suggested by: (1) the distribution of the two hemirhythms in the stratigraphic column, (2) the presence in the red hemirhythm of large slump structures, contorted laminations, and pebbly claystone, and (3) by the internal sedimentary structures of the coarse fraction.

The Beekmantown Group (Lower Ordovician) of the Saint-Flavien reservoir has produced 162x10 6 m 3 (5.7 bcf) of natural gas between 1980 and 1994. The conversion of the field into gas storage was initiated in 1992 and the pool became operational in 1998. Integration of structural and sedimentologic features, carbonate and organic matter petrography and geochemistry for 13 drill holes is used to define a tectonic-sedimentologic-diagenetic model for porosity evolution in these reservoir dolostones.The Beekmantown Group consists of numerous fifth-order shallowing-upward cycles 1.0 to 7.0 m thick (average of 2.4 m). Each cycle consists of a basal shale deposited during the initial flooding of the platform which was subsequently covered by a shoaling succession of subtidal and intertidal limestones to intertidal dolostones.Early dolomitization has produced intercrystalline porosity and preserved some moldic pores in the intertidal facies. Near surface, post-dolomite karstification has created vugs that were subsequently filled by early marine calcite fibrous cement based on the δ 18 O and δ 13 C ratios of calcite. Early burial elements consist of horizontal stylolites, pyrite and sphalerite.Late migrated bitumen was thermally altered or vaporized as native coke under deep burial conditions exceeding 240ºC, partly due to overthrusting of Appalachian nappes. Under these conditions, breccias and fractures were generated and subsequently filled with K-feldspar, quartz, illite, and xenomorphic and poikilotopic calcite. The δ 18 O of the poikilotopic calcite and homogenization temperature of coeval fluid inclusions indicate formation under high temperatures (T h about 260ºC). Horizontal shear zones and marcasite-rich vertical stylolites were produced during folding and thrusting. Dissolution has preferentially affected late fracture-filling calcite and generated most of the actual porosity during or soon after the Taconian Orogeny. The relationship between the occurrence of smectite and this type of porosity indicates the low temperature condition of this dissolution (T <100ºC). Porosity in the Saint-Flavien reservoir has been mostly produced by fracture-controlled, late to post-Taconian dissolution of early to late calcite in the intertidal dolomitic slightly porous facies at the top of rhythmic cycles that compose the Beekmantown Group. RÉSUMÉLe Groupe de Beekmantown (Ordovicien inférieur) du réservoir de Saint-Flavien a produit 162x10 6 m 3 (5.7bcf) de gaz naturel entre 1980 et 1994. La transformation du champ en une facilité d'entreposage souterrain fut initiée en 1992 et devint opérationnel en 1998. Une intégration d'éléments structuraux et sédimentologiques, de la pétrographie et de la géochimie des carbonates et de la matière organique provenant de 13 forages aide à définir le modèle tectoniquesédimentologique-diagénétique pour l'évolution de la porosité des roches dolomitiques du réservoir.Le Groupe de Beekmantown est formé de nombreux cycles de cinquième ordre de diminution progressive de la tranche d'eau, d'épaisse...