Scoperta nel 2002 durante una campagna di prospezioni, la Grotta del Rio Secco si trova a 580m di quota sull’Altopiano di Pradis nel settore orientale delle Prealpi Carniche. Si tratta di una grande grotta-riparo che si apre sul versante sinistro dell’incisione del torrente omonimo, a circa 20m di altezza rispetto al letto attuale. Il riparo è orientato a S e protegge per 6-7 metri un’ampia galleria quasi totalmente riempita di detriti tranne nel settore atriale, da dove prosegue per una decina di metri verso l’interno con direzione N/NW. L’area è limitata verso l’esterno da un cordone di grandi massi di crollo disposto grossomodo N-S, ai quali si appoggiano due muretti a secco, probabili resti di un ricovero utilizzato fino a poche decine di anni fa (figura). Il deposito forma una falda esterna che culmina in corrispondenza dell’attuale linea di pioggia, dove i grandi massi di crollo delineano l’estensione originaria dell’area riparata. L’importanza del sito è stata colta in seguito all’apertura di un sondaggio nel 2002 che ha messo in luce una successione stratigrafica di 1,70 m di spessore senza peraltro raggiungere il substrato lapideo. Il contenuto paleontologico e archeologico di alcune delle unità stratigrafiche esposte dallo scavo ha rilevato l’esistenza di resti e manufatti ascrivibili al Paleolitico superiore, presumibilmente l’Epigravettiano e al Paleolitico medio finale, come provato anche dalla data radiocarbonio di 37.790±360 BP (LTL429A).

Nei mesi di settembre e ottobre ha avuto luogo la campagna di scavo 2011, incentrata sull’esplorazione della successione stratigrafica nell’area atriale della cavità, dove sono state scavate l’unità BR1, che conserva il livello US6 datato all’inizio del Gravettiano, e l’unità BIO1, che contiene le US5tetto, 7, 5, precedentemente individuate nella campagna 2010. All’interno di US6 sono stati individuate due strutture di combustione, SI caratterizzata da una notevole concentrazione di macrocarboni in associazione con un resto di castoro semicombusto e S2, marcata da un orizzonte rubefatto. La loro posizione è in sintonia con la morfologia della cavità atriale, nella fascia centrale dell’accesso. Sono stati recuperati numerosi resti faunistici che permetteranno di inferire sugli agenti di accumulo e formulare alcune ipotesi riguardo le modalità di sussistenza dei gruppi umani. Nell’unità gravettiana le specie più rappresentate sono la marmotta e l’orso delle caverne, ma il loro apporto non è riconducibile alla presenza umana. Tracce di modificazioni antropiche sono state individuate su resti di ungulati di varie taglie. Nella macro-unità BIO si conferma la prevalenza di orso delle caverne e marmotta, quest’ultima, tuttavia, non legata all’attività antropica. Lo sfruttamento delle risorse faunistiche è invece documentato da cut-marks, resti combusti e stigmate da impatto su diafisi di ungulati di grande taglia, a documentare il recupero del midollo. Di notevole interesse sono le tracce di macellazione su resti di orso (Ursus sp.) e orso delle caverne (Ursus spelaeus) provenienti dalle USS 7 e 5 tetto collegate al recupero di carne e pelle. I manufatti litici confermano la presenza del Paleolitico medio e del Paleolitico superiore. L’insieme musteriano si compone di schegge debordanti e supporti associati al metodo discoide e alla produzione Levallois, alcuni dei quali trasformati in raschiatoi. La scelta della materie prime conferma i bacini fluviali circostanti come principali zone di approvvigionamento. I reperti gravettiani constano di manufatti ricavati principalmente da selci ascrivibili a formazioni carbonatiche delle Prealpi Venete. Si notano grattatoi, bulini e frammenti di armature. La cavità si conferma di potenziale interesse per acquisire indicatori di mobilità, di occupazione del territorio e di sfruttamento delle risorse in una fascia di cerniera tra la pianura e la regione alpina. La prosecuzione del progetto fornirà elementi interpretativi sulla presenza dei gruppi neandertaliani e gravettiano in una zona ritenuta periferica rispetto alla vasta pianura nordadriatica che si estendeva verso sud.

The 2012 field campaign went deep in the exploration of the stratigraphic sequence behind the entrance to the cave. Here, contexts BIO1, containing layers 5 top (ex roof), 7, 5 and 8 were excavated. Numerous faunal remains were recovered which provided evidence for the occupants methods of subsistence. Traces of human intervention were visible on the remains of ungulates of various sizes. In the macro-unit BIO, the prevalence of cave bear and marmot was confirmed, the latter however showing no signs of anthropological activity. The exploitation of faunal resources was documented by cut marks, burnt remains, and impact trauma on the diaphises of large ungulates, documenting the removal of the bone marrow. The butchery marks on the remains of a bear ( _Ursus sp._ ) and cave bear ( _Ursus spelaeus _) from the layers US 7 and 5 top, resulting from the removal of the meat and skin, were of particular interest. The lithic artefacts shed new lights on the Middle Paleolithic occupations. The Mousterian assemblage comprises edge flakes and striking platforms/anvil stones associated with the discoid method and Levallois production, some of which were transformed into scrapers. The choice of raw materials confirmed the surrounding river basins to be the main source. Layer 5 top yielded clear evidence of technological variability, as suggested by the recovery of fragmentary centripetal Levallois flakes, thick tiny flakes with inclined butt possibly relatable to Discoid technology, and one large centripetal flake with a flat, inclined butt. Two pieces show features distinct from the remaining sequence: a short blade struck from the ventral face of a core-on-flake and a flake bearing a partially retouched back opposite to a thin edge affected by shallow, invasive scars. The cave could potentially provide evidence regarding mobility, occupation of the territory and exploitation of resources in an area between the plain and alpine region. Continuation of the project will provide evidence about the presence of Neanderthal and Gravettian groups in an area considered peripheral with respect to the vast northern Adriatic plain, which extends to the south.

The aim of the 2013 field campaign was to enlarge the excavated area at the level of the late Mousterian sequence and to explore the stratigraphic sequence below the oldest archaeological level known. A pit dug under the rockshelter outside the tunnel in squares H11 and H12 has exposed for 1.5m stony sediment intensively reworked by burrowers but stopped on large boulders. Behind the entrance of the cave, the archaeological excavation concerned layers 5top, 7, 5 and 8 which yielded several well preserved bones and flaked stones. Thickness varies between 50 and 15 cm, due to local disturbance produced from burrowing animals. In some squares, layer 8 shows concentration of bones of large herbivores (Bison priscus, Bos primigenius, Megaloceros giganteus), bear (Ursus spelaeus) and other common ungulates like Cervus elaphus and Capreolus capreolus. In all layers the prevalence of cave bear and marmot was confirmed, the latter however showing no signs of anthropological activity. The exploitation of faunal ungulates of various sizes and of bear is documented by cut marks, burnt remains, and impact trauma on the shafts of large ungulates, documenting the removal of the bone marrow. Bone of particular interest due to the presence of butchery marks and other traces resulted from the removal of the meat and skin are those of bear (Ursus sp.) and cave bear (Ursus spelaeus) found in layers 7 and 5top. An exceptional finding is represented by a rare cut-marked pedal phalanx of cfr. Aquila chrysaetos found in proximity of layer 7 bears. The ensemble of human modification traces suggests the intentional removal of the claw from the footh of this very large raptor. Other cultural findings are few retouchers made of fragmented bone shafts both of herbivores and bears. The lithic artefacts shed new lights on the Middle Paleolithic occupations. The Mousterian assemblage comprises flakes associated with the discoid and Levallois methods. The choice of raw materials confirmed the surrounding river basins to be the main source. Layers 5top, 7 and 8 yielded small side, bilateral and convergent scrapers among the retouched tools. In addition, layer 8 has yielded scrapers thinned on the lower face. The cave confirms a potential evidence of human mobility and exploitation of lithic and faunal resources in this strategic area between the plain and the alpine region. Continuation of the project will provide evidence about the latest presence of Neanderthals.

The aim of the 2014 field campaign was enlarge the excavated area at the level of the late Mousterian sequence, carrying on the work already begun in the field campaign of 2013, and explore a new area 3m2 large close to the vault of the cave in south-east in size in the squares G 10-11-12, F 10-11-12, E 10,11,12. The top layers shows a presence of pottery and large combustion structures attributable to the Bronze Age and more recent times. In the inner part of the cave (squares I, H, G 17) the archaeological excavation concerned layers 6, 5top, 7, 5 and 8 which yielded well preserved bones and flaked stones. Thickness varies between 30 and 10 cm, due to local disturbance produced from burrowing animals. In some squares, layers 5top, 5 and 8 shows concentration of bones of large herbivores (Bison priscus, Bos primigenius, Megaloceros giganteus), bear (Ursus spelaeus) and other common ungulates like Cervus elaphus. In all layers the prevalence of cave bear and marmot was confirmed, the latter however showing no signs of anthropological activity. The exploitation of faunal ungulates of various sizes and of bear is documented by cut marks, burnt remains, and impact trauma on the shafts of large ungulates, documenting the removal of the bone marrow. Bone of particular interest due to the presence of butchery marks and other traces resulted from the removal of the meat and skin are those of bear (Ursus sp.) and cave bear (Ursus spelaeus) found in all Mousterian layers: 5top, 7, 5 and 8. Other cultural findings are few retouchers made of fragmented bone shafts of bear. The lithic artifacts confirms the data obtained in previous excavations concerning the Middle Paleolithic occupations. The Mousterian assemblage comprises flakes associated with the discoid and Levallois methods. The choice of raw materials confirmed the surrounding river basins to be the main source. Layers 5top, 7 and 8 yielded small side, bilateral and convergent scrapers among the retouched tools. In addition, layer 8 has yielded scrapers thinned on the lower face. In the last field campaign 2014, the cave confirms a potential evidence of prehistoric human occupation. The increase of faunal, lithic and carbon remains shows a scenario more clear of the exploitation of the Friuli area in prehistoric times, while the data obtained in the new excavation area gives important information of human exploitation of the cavity even in Historical periods. Continuation of the project will provide evidence about the latest presence of Neanderthals.