Poster Number 1
This preliminary study presents the results of ~57 mineral samples that were investigated by means of X-ray diffraction, scanning electron microscope, and electron microprobe analyses. In addition, oxygen and sulfur measurements (δ 18O and δ 34S) on sulfate speleothems were performed with the scope of ruling out the origin of cave sulfates (i.e., vadose, hypogene, bacteriogenic, etc.). The minerals identified so far in Salitrari, Ion Barzoni, Diana, Adam, Despicatura, and Grota cu Aburi caves, are: calcite [CaCO3], aragonite [CaCO3], gypsum [CaSO42H2O], anhydrite [CaSO4], pickeringite [MgAl2 (SO4)422H2O], halotrichite [Fe2+Al2(SO4)422H2O], kalinite [KAl(SO4)211H2O], melanterite [FeSO47H2O], hydroxylapatite [Ca5 (PO4)3(OH)], carbonate-hydroxylapatite [Ca5 (PO4,CO3)3(OH)], brushite [CaHPO42H2O], darapskite [Na3 (SO4)(NO3)H2O], and nitratine [NaNO3]. The phosphates were precipitated in a typical vadose environment, whereas nitrates and most sulfates are of bacteriogenic/ hypogene origin.
Based on our preliminary isotopic data, the gypsum from the Barzoni Cave shows to be dominantly hypogene in origin with a depletion in the heavy isotope of sulfur and a slight enrichment in oxygen isotopic values (δ 34S (SO4) = -23 -28 and δ 18O (SO4) = 0.2 4.3).