This was the 14th campaign of excavations at Poggio di Spaccasasso, in the Maremma Regional Park (Alberese – GR).

Excavation continued in the north-west and south-west sectors of the plateau quarry, which were opened in 2017. Work also continued in the north-east and south-east sectors where the investigations were suspended in 2016. The reopening of the north-east sector aimed to excavate the hearth area, “hearth 1”, characterised by a hardened accumulation of calcinated limestone probably mixed with ash. This accumulation contained a moderate quantity of vegetal charcoal and several gabbro hammerstones (intact and fragmented).

The preliminary analysis of the FTIR of the hearth’s hardened deposit presently in progress at the Bioscience Research Center di Fonteblanda (GR) has so far identified high levels of mercury (Hg) while cinnabar (HgS) seems absent. This result appears consistent with the type of structure analysed. When exposed to moderately high temperatures the mercury sulfide that was extracted at the site releases mercury. On the contrary, cinnabar, easily identifiable by its red colour, was present in dense concentrations throughout the earthy deposit and in the debris from the mineral reduction occupying the extraction area in the parts not subject to heat from the fires.

As often mentioned, the use of fire in the extraction process is documented at Spaccasasso both in the phases of breaking down the limestone containing the cinnabriferous veins and in the reduction phases, and this due to the extreme hardness of the limestone close to the cinnabar deposits. It is certainly plausible that the use of fire, despite the good level of techniques for its control, could not however prevent the loss of a part of the extracted cinnabar in the form of mercury. The area of this hearth could be interpreted as the place for the separation of the mineral from the rock containing it.

Continuing towards the western edge of the plateau, still within the North area, loose brown soil, some very dark, was removed. It contained moderately large limestone blocks and intact and fragmentary mallets made of quarzarenite and occasionally gabbro. The layers removed sloped down towards the valley, contrary to those in the North-east area, all more or less horizontal or sloping towards the extraction front.

The almost exclusive presence of quarzarenite tools poses the still unanswered question of the functional or chronological significance to be attributed to the tools made in this material. At present, the area cannot be dated using methods producing an absolute chronology and the archaeological data itself does not provide a clear chronology for this level. In this area of the plateau, the presence of root systems that have clearly disturbed the archaeological deposit continues to be problematical and caution is needed in the reading of the evidence. In the south area, the sector next to the east wall was uncovered, on which the mineshaft opened. There was another scatter of moderately hardened calcinated limestone mixed with fine – very fine debris in which limestone chips and medium-large blocks were dispersed, which bordered the layer to the west. Vegetal charcoal and gabbro chippings were also present here. The type of deposit, its position, and slope towards the shaft opening suggest it can be interpreted as an accumulation of detritus from the digging of the shaft.

Several negative layers containing human bones and pottery fragments were also identified in the south area, but towards the west edge of the plateau. As seen last year, this evidence can be associated with later activity, perhaps mining, in the phases post-dating the period when the plateau was used as a cemetery area during the Copper Age.