Celestine from Valea Sarii (Vrancea region): New Data and Crystal Structure Refinement

In the paper has been analyzed the crystal structure of a celestine sample from Valea Sarii (Vrancea region, Romania) located in the Eastern Carpathians Foredeep. The celestine sample was also studied by optical microscopy, chemical and thermal analysis. The unit cell parameters of the celestine structure refined in the space group Pnma were: a=8.39769 �, b=5.38415 �, c=6.88167 �, Z=4. The chemical composition of the celestine crystals was determined by EDX analysis. The optical characteristics of the sample were studied by optical microscopy. A new set of the unit cell parameters and fractional coordinates of the celestine crystal structure were determined. Also were determined the bond lengths in the Sr-O12 and SO4 polyhedra. The sample was collected in the massive mineralization area of the Valea Sarii ore deposit, the largest celestine ore deposit in Romania.

Tectonic specificities and macroseismic characteristics of the south-west of the Russian Platform

The tectonic specification of the West-European (Russian) platform (by the case territory of the Republic of Moldova) has been examined and its reflection in helium, macro seismicity, hydrogeochemical and geophysical fields as well. The modern ideas about seismically tec-tonic of the Vrancea region were summarized. Helium detailing mapping of groundwater and allocation of old/young faults contribute considerably to this study. As well a comparative map of tectonic faults allocated by magnetic, gravity, geological and geomorphological data has been prepared. The background and local macroseismic maps were performed on data of the Vrancea earthquake from 04.03.1977. The character of the background map was determined by the mantle heterogeneity and old tectonic faults with spreading dislocation. The yang tectonic faults, which are oriented perpendicular to seismic waves, create positive anomalies of the macroseismic field. The yang faults, which are oriented tangential to seismic waves, create shadow effects of decreasing shaking. Local macroseismic fields are connected with structural features of the upper part of the sedimentary cover.