MAJOR AND MINOR ELEMENT GEOCHEMISTRY OF LOWER APTIAN SEDIMENTS FROM THE NW GERMAN BASIN (CORE HOHENEGGELSEN KB 40)

Two hundred and thirty-three samples from the Hoheneggelsen KB 40 dril l core, located 30 km SE of Hannover, Germany, were analysed for 12 ma jor elements, 14 minor elements, degree of pyritization, and S-isotopi c composition. This early Aptian sequence consists of three lithologic al units: an upper marry section (Hedbergella mart) that was deposited under strictly oxic conditions, an underlying fish share horizon (''F ischschiefer'') which represents an anoxic stagnant phase of sedimenta tion, and a lower clay-rich section (dark coloured claystones) includi ng scattered thin paper shale horizons (''Blattertone'') reflecting a suboxic to anoxic water column. Major and minor element profiles minor the changing sedimentology of the individual units which can be expla ined by different palaeoceanographic and climatic conditions. A major shift in major element ratios, which is probably a result of a differe nt source of the terrigenous detrital material or of variations in wea thering intensity, took place before the onset of fish share sedimenta tion. The high-resolution sampling and analysis (sampling intervals 1 to 5 cm) allows the detection of small-scale variations in element con tents in individual sedimentary units and in transitional stages of su boxic to anoxic (dark claystone to paper shale) or anoxic to oxic (fis h share to Hedbergella mart) palaeoenvironments. (C) 1998 Academic Pre ss.