Århundredets afhandling
6. Bromley, R. G. 1980: Enhancement of visibility of structures in marly chalk: modification of the Bushinsky oil technique. Bulletin of the Geological Society of Denmark 29, 111-118 Abstract: The outwardly monotonous appearance of white chalk is deceptive, yet the several techniques that have been appied to enhance visibility of hidden structures hve all had limited success. A technique published by Bushinsky in 1947 produces excellent results withy chalks containing a trace of clay minerals. Bushinsky's technique involves incomplete impregnation of chalk samples with light machine oil, but still better results were obtained by lightly brushing oil onto smooted surfaces of chalk. The heightened contrast of the structures thereby achieved can be still further increased photographically by use opfr high contrast line copy film. the results obtained are compared with those using flourescence by ultraviolet radiation or by merely wetting the chalk. Both contrast and resolution are better with oil than with water or ultraviolet.
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Begrundelse for nomination til væsentligste DGF-artikel i det 19. århundrede:
Artiklen beskriver en enkel, billig teknik til studiet af sporfossiler i skrivekridt på flader af alle størrelser. Da teknikken blev præsenteret var den en vældig inspiration til at forstå, at bioturbation er en væsentlig årsag til at visse finkornede sedimenter fremtræder som strukturløse. Artiklen har bidraget til at belyse skrivekridtets aflejringsmiljø.
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