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Muierilor Cave is one of the most important caves in Romania from paleontological, biological, and archaeological points of view. A newly discovered chamber, with unique yellow calcite crystals, fine-grained crusts, and black sediments, is connected to the upper levels that contains fossil bones and a large pile of guano. Samples were taken from this chamber and another passage to investigate the diversity of microorganisms related to the substrates and identify potential pathogenic taxa for humans and animals. Chemical, mineralogical, and whole community 16S rRNA gene-based metabarcoding analyses were undertaken, and the base of the guano deposit was radiocarbon dated. Metabarcoding of the analyzed samples found that ~16% of the identified bacteria are potentially pathogenic to humans. Moreover, more than 87% of the identified genera were not previously reported in caves. We identified bacteria involved in the phosphate cycle that can only originate from the organic deposits inside the cave, such as the bats' guano in the touristic, upper level, or the fossil bones. Our study indicate also the guano deposit as the possible source of potentially pathogenic microorganisms. The results on the microbiome of different deposit types unravel the diversity of microorganisms and indicate the potentially pathogenic taxa for humans and animals.

In this study, we describe a sedimentary deposit situated above Ascunsă Cave (SW Romania) that should be in depositional connection with coeval stalagmites from the cave. We excavated a 2.5 m deep soil profile and took contiguous bulk samples every 5 cm. Soil samples were analyzed for clay mineralogy, grain size, chemical composition, magnetic susceptibility, and stable carbon isotopes. Radiocarbon dating revealed that the soil is of Holocene age, and presents a depositional hiatus between 5.4 and 2.3 thousand years before the present. Due to the open system behavior of soils and the mobility of organic matter, a few hundred years of uncertainty should be considered for the duration of this hiatus. The fine fraction is dominated by silt, while the clay mineralogical association is made of illite, chlorite, kaolinite, vermiculite, and illite–vermiculite and illite–chlorite mixed layered minerals. The sediment source of this soil is represented by a nearby mélange complex, as well as by an underlying terra rossa-type soil. As this latter type of soil is widespread in our study area, we performed luminescence dating on two samples from a representative location close to our site and it appears that this type of Mediterranean soil was formed during the Last Interglacial period. δ13C variability in soil organic matter and a stalagmite from the cave are compared well, and could help future studies identify modifications in isotopic fractionation processes within the cave.

Caves often hold valuable palaeoclimate archives including speleothems, fossil remains, and clastic sediments that complement each other. This paper presents a multi-archive interdisciplinary study of an extensive deposit of fossil mammals from the scientific reserve in the Muierilor Cave, Southern Carpathians, Romania. We present two new palaeontological excavations that indicate a high abundance and diversity of MIS 3–2 fossil mammals (carnivores, omnivores and herbivores) synchronous with the early modern humans known from this cave. Using geochronological and sedimentological methods, we present a general reconstruction of the cave evolution between ~120 kyr B.P. and the Holocene. The study is based on a combination of geochronological tools including OSL dating of sediments, U/Th dating of speleothems, and radiocarbon dating of fossil remains, with a total of 54 ages. Based on U/Th dating of speleothems from stratigraphically-relevant positions, we show that the MIS 3 assemblage of fossil mammals were massively reworked and deposited during the post-LGM deglaciation, slightly earlier than previously known for the Southern Carpathians. On the other hand, several young radiocarbon ages of cave bear samples suggest that the Southern Carpathians might have been functioning as a glacial refuge for this species as late as ~22 kyr B.P.

The Olteț River Valley in southern Romania hosts a large number of fossiliferous sites, the richest of which is Valea Grăunceanului. Based on biochronological estimations, these sites were assigned to the Late Villafranchian (MN17/MNQ1), at ~2.0-1.8 Ma. As yet, no other dating methods were employed and our present study aims to provide the geological and geomorphological background for radiometric and trapped charge dating, as well as for the stratigraphic correlation of these sites. These deposits are represented by fluvial-lacustrine sediments belonging to the Dacian Basin, a part of the Eastern Paratethys domain. Our approach is to create a regional stratigraphic column onto which to place the fossil sites. We first created a high-resolution 3D model of the surface using UAV technology. Further, we sampled sediments from several sections and determined their grain size and mineralogy. We also sampled pedogenic carbonates and fossil teeth for preliminary geochemical analysis, in preparation for uranium series dating. Although no human fossils have been found so far in the Olteț River Valley, the site is important for understanding the environment used by early humans to migrate out of Africa. These sites are close both in time and space to important anthropological sites such as Dmanisi, Khapry or Kozarnika, while being part of an area dominated by large water bodies that included the Pannonian, Dacian and Euxinic lakes.