Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 82. (Budapest 1990)

Dulai, A.: The Lower Sinemurian (Jurassic) brachiopod fauna of the Lókút Hill (Bakony Mts., Hungary). Preliminary results

The brachiopods are infilled partly by red micritic limé mud and by white coarse-grained sparry calcite; their ratio shows considerable change's. A continuous transition ca'n be found from the 100% lime mud to the 100% sparite. The examination of this relationship may be important, because we can conclude to the rate of sedimentation. The lime mud infilling indicates a slow sedimentation: after the death of the brachiopod, the slightly opened valve has time to be completely filled with mud. In the case of a fast burial, the shell has not time to be completely filled. Later the coarse-grained D PC. 5Ó0 1000 C B A pc. —I r 10 20 30 D C D C B B 6 C 8 10 20 40 60 80 100 d mm X) 15 20 Fig. 7. The average values of the examined features in the four intervals (Summary of the palaeoecological examinations

.)(a = specimen number, b = taxon number, c = the saturation with sparite, which is proportional to the sedime'ntation rate, d = the disintegration percentage of valves, e = size distribution) sparite precipitates from the migrating solutions, in the empty space. For this reason: the more sparite we have, the faster sedimentation we can reckon with. I examined the saturation with sparite (Fig. 5), i.e. how many percent of volume of the whole brachiopods, found in one layer, were filled with sparite

. The size distribution of brachiopods can be seen in Fig. 6. The average of the biggest size of specimens found in one layer is indicated by dots, as well as by a continuous line. The dotted line shows the dispersion around it.