TY - JOUR L1 - http://www.journals.pan.pl/Content/111196/PDF-MASTER/1990-3-4_331-344.pdf L2 - http://www.journals.pan.pl/Content/111196 PY - 1990 IS - No 3-4 EP - 344 KW - Arctic KW - Spitsbergen KW - Jurassic KW - sedimentology KW - condensed phosphorite A1 - Krajewski, Krzysztof PB - Polish Academy of Sciences PB - Committee on Polar Research VL - vol. 11 CY - The condensed Brentskardhaugen Bed (Toarcian-Bajocian) in central Spitsbergen is a low-grade phosphate-bearing horizon (4—12% P205) occurring at the base of the Jurassic transgressive shelf succession. This condensed sequence was deposited in a shallow marine environment of restricted sedimentation which, occasionally, was capable of producing indigenous sandy to conglomeratic phosphate nodules. The nodules grew within the sediment as a result of precipitation of microglobular carbonate fluorapatite (CFA) during a very early stage of diagenesis. It is inferred that the development of successive phosphate nodule generations was associated with recurrent sea-level rises ascending deeper shelf waters into the shallow environment and the consequent high biological productivity events. The enhanced phosphorus flux to the shelving bottom during these events reinforced widespread sea-floor phosphoritization. Rare episodes of intense CFA emplacement rather than slow phosphate fixation within the seabed are considered essential for the phosphorus concentration in this condensed sequence. DA - 1990 T1 - Phosphoritization in a starved shallow shelf environment: the Brentskardhaugen Bed (Toarcian-Bajocian) in Spitsbergen SP - 331 UR - http://www.journals.pan.pl/dlibra/publication/edition/111196 T2 - Polish Polar Research ER -