Porifera-microbialites of the Lower Liassic (Northern Calcareous ...

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8.2. Major and Trace Elements
Weight ratios of major and trace elements were measured on bulk samples of 6 ferromanganese
crusts and 4 corresponding sediments. As a result, the element analyses show that the
distribution patterns are quite similar in both sediments and crusts, but the concentrations in the
ferromanganese precipitates are much higher (Fig. 45). All samples show definite accumulations
of predominantly V, Ni, Zn, Sr, Ba, and Pb. The different amounts are most likely caused by use
of bulk samples that vary in their content due to the detrital character of the sediments and the
laminated composition of the crusts. In addition, measurements of quantitative XRF- and liquid
ICP-mass spectrometry were compared with results of semi-quantitative point analyses by laser
ICP-mass spectrometry in order to verify the validity of bulk analyses. The comparison between
bulk and point analyses revealed some strong differences in the measured amounts of trace
elements, but not in the values of rare earth elements (REE), thus the ratio of REE seems to be
homogeneously dispersed in all samples. In the sediments the REE show quite uniform patterns
(Fig. 46), whereas the crusts display very high values of Ce (up to 1500 ppm in the
Adnet/Lienbacher Quarry – Low. Sin. Crust) and small positive Gd-anomalies (1.05-2.22).
Fig. 45. Trace elements in Fe/Mn-crusts and corresponding sediments from Steinplatte/Plattenkogel (locality S1)
and different localities of the Osterhorn block. Measured by liquid icp-mass spectrometry, except Zn by XRFanalyses.
For all ICP-MS datas see the supplement.