Sediments, deposits and minerals discovered in the caves evidenced the peculiarity of the “carsism” of the Caves of Frasassi. Basic element is the presence of great and imposing deposits of chalk. This chalk sediment, deposited in the rooms after sulphureous water's cooling by river Sentino, presents itself with a white saccaroidal and microcrystalline structure and it is covered with microcrystalline geminate crystals. These deposits reach their best in Ancona's Abyss.
Here the chalk, 10 metres thick , passes from a white saccaroidal and microcrystalline structure to a grey microcrystalline structure. Giant stalagmites and columns with holes and cracks filled with white microcrystalline chalk are peculiarities of the Big Cave of Wind.