Sarah Tomasetti: Geo-Luminescence

Sarah Tomasetti: Geo-Luminescence

Limestone is formed in the sea over deep time. The spent skeletons of sea life fall to the sea floor and are compressed over millions of years to become limestone. Simple, alkaline, chemically connected to our mammalian bones and teeth. We slake lime by heating up limestone and driving off the carbon dioxide to produce quicklime to which water is added, to slake its thirst.

This is the lime cycle and half-way through, the lime putty is volatile but once mixed with sand and rendered on a wall, it enters the final phase of curing, re-sequestering carbon from the atmosphere and absorbing pigment and water into itself to make a breathable and weatherproof surface. It’s a curious thing that limestone, which erodes so readily in both rain and ground water, can magically resist the weather when slaked and cured.

Geo-luminescence is a material exploration of the capacity of slaked lime to echo its own origins in the deep sea, its uplift into the air to become mountainous, and its dissolution to form karst landscape above and below ground. Geo-luminescence is a material exploration by artist Sarah Tomasetti of the exchange of matter and light where water and sedimentary stone meet, where one becomes the other and plant and animal life grows.. Coral reefs form on submerged limestone and draw calcium carbonate from the sea. Tomasetti mixes calcium carbonate powder with pigment and lime putty, adding beeswax to render the lime translucent and reveal the unique patterning each pigment creates during curing

The banners fall through the air, crossing one another to echo the endless atmospheric movement that occurs within the manifold of sky and earth. At floor level they are lit from beneath to evoke the immense heat and energy contained below ground that moves from the molten core of the earth through to the crust.

The Latrobe Valley has a unique geology with one of the largest deposits of brown coal in the world, itself a remarkably effective insulator from the heat below, surrounded by a vast underground aquifer. Latrobe Valley has supplied crucial energy for decades and has the ideal conditions for the research into geothermal technologies occurring locally in collaboration with scientists worldwide.

Human and weather world atmospheres combine continuously, from the life-giving fog that nourishes plants and cleanses the air to the ways that the breath from bodies binds the substance of the ground and the medium of the air together. The atmospheric conditions of the Anthropocene will be traceable in the future through embedment in the geological layers forming now and ancient life contributes its chemistry to the present.

Geo-luminescence is a sensory meditation on these exchanges as they occur, now and through deep time, interpreted through the material technology of fresco, itself a geological process based on the liveliness of limestone in all its forms.

Image description: Slaked lime foraged and purchased pigments and encaustic wax on muslin. LED lights, perpex armature.
Sarah Tomasetti, Geo-luminescence III, 2026