Living in a karstic spring: humans, animals, and sediments at Zala Cave (northern-central Croatia) during the Late Glacial and Early Holocene

This study presents a geoarchaeological investigation of Zala Cave, located in northwestern Croatia, a site of exceptional significance due to its position in a key geographical corridor between the Adriatic coast and the continental Balkans, a region largely lacking comparable sequences. The cave provides rare evidence of human occupation spanning from the Late Upper Palaeolithic through the Middle Ages. Geoarchaeological, sedimentological, and micromorphological analyses of the cave deposits elucidate the interplay between human occupation, sedimentary processes, and environmental change in a karstic landscape strongly influenced by subterranean hydrology. The stratigraphic sequence documents alternating phases of fluvial sedimentation, frost-related reworking, and human use of the cave. The mineral composition of the deposits, dominated by siliciclastic grains derived from distant Triassic formations and possibly reworked loess, confirms the cave's hydrological connection to external catchments. Sediment architecture reveals periodic flooding from the underground Đulin Ponor–Medvedica–Izvor-Špilja Gojak cave system, which repeatedly transformed the cave into a spring outlet. Periodical erosion and redeposition of sediments generated gaps and mixed layers within the cultural succession, and disrupted the stratigraphic continuity. Epigravettian layers reveal short-term occupation episodes by Late Upper Palaeolithic foragers, while an in situ Mesolithic hearth attests to later visits during more temperate conditions. Sporadic Copper and Bronze Age activity reflects shifting land-use strategies, mostly pastoral. The absence of Neolithic layers and remains hints to possible erosional removal of the Neolithic horizon. Micromorphological evidence of periglacial structures, combustion features, and dung accumulations, demonstrates subsequent and/or alternating phases of cold-climate sedimentation, dwelling, and pastoral use. Overall, Zala Cave represents a key inland node linking the Adriatic and continental Balkans, offering new insights into human mobility, environmental adaptation, and the geomorphic evolution of a karstic corridor during Late Pleistocene–Holocene climatic transitions.