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ABSTRACT. The Purcăreţ -Boiu Mare Plateau and the southern edge of the Baia Mare Depression, in Sălaj and Maramureş Counties, NW Romania, host over 200 caves located in limestones ranging in age from Upper Eocene to Badenian. The carbonate rocks are interposed with non-karst rocks consisting of shales, sandstones and marls. Four caves hosted by limestones of different lithologies have been investigated for secondary minerals in the composition of their speleothems. Calcite, gypsum, goethite, jarosite, brushite, hydroxylapatite and taranakite were found in the composition of crusts, crystals, aggregates and earthy masses. The mineral association was characterized by means of X-ray diffraction and scanning electron microscopy. Gypsum, goethite and jarosite resulted from sulfide oxidation, whereas the phosphate associations formed through the interaction of phosphoric acid from bat guano with the limestones and detrital sediments. In Lii Cave, hydroxylapatite was also identified in black crusts deposited on fossil rib fragments within the limestones.

2 Babeş-Bolyai Uni ver sity, De part ment of Ge ol ogy and Cen ter for In te grated Geo log i cal Stud ies, 1, M. Kogălniceanu,

The objective of this study is to describe the composition of the carbonate elements from the upper Albian–Cenomanian Postăvaru Conglomerates. Eight sections were studied. Two major types of conglomerates are identified in the field and thin sections: polymictic orthoconglomerates and paraconglomerates. Carbonate clasts are dominant in both types of conglomerates. Other subordinated clasts are composed of quartzites, sericite-chlorite schists and gneisses. Facies data allow reconstructing the depositional environments, while microfossil assemblages were used to establish the age of the studied carbonate clasts. The identified microfacies characterize a large variety of depositional environments, ranging from basin to shallow water environments (platform margin and inner platform depositional settings). The identified microfossil associations are indicative for three biostratigraphic intervals: Kimmeridgian–Tithonian, Tithonian–Berriasian and Berriasian–? lower Valanginian.