[EN] (HR below)
The place is open daily from 9:00 to 22:00. The entrance is free. The opening times may vary during events in the tunnels.
Dripstones, also known as speleothems, are geological formations typically found in caves, mines, or other subterranean environments, resulting from the precipitation of minerals carried by dripping water. They are distinguished by their unique shapes and structures, including stalactites, stalagmites, and columns, which form through intricate chemical processes.
The formation of dripstones begins with the interaction between water and limestone, a common mineral in many cave systems. Initially, rainwater seeps into the soil, absorbing carbon dioxide and organic acids as it percolates through the ground. Upon reaching the limestone bedrock, the acidic water dissolves calcium carbonate (CaCO3) (lime) from the rock, creating a solution known as calcium hydrogen carbonate (Ca (HCO3) 2), which is soluble in water.
As this solution infiltrates the cave, it encounters openings in the cave ceiling, allowing it to drip into the cavern below. Upon exposure to air within the cave, carbon dioxide is released, causing the calcium hydrogen carbonate to revert to its insoluble form, calcium carbonate (lime). This lime precipitates out of the solution and gradually accumulates, forming the characteristic structures of dripstones over years.
Stalactites, which hang from the cave ceiling, are formed as the calcium carbonate-rich water drips downward, leaving behind mineral deposits with each drop. These deposits build up over time, creating elongated, icicle-like formations. Stalagmites, on the other hand, form on the cave floor directly beneath stalactites. As the dripping water impacts the ground, it releases carbon dioxide, causing the precipitation of calcium carbonate. Over time, these mineral deposits accumulate, resulting in cone-shaped formations that rise upward from the cave floor.
In some cases, stalactites and stalagmites may eventually merge to form columns, known as stalagnates. If the water does not drip but rather flows, it can create different columns on the walls of cavern. The coloration of dripstones can vary depending on the minerals present in the water and the environment in which they form, resulting in a range of hues from white and translucent to various shades of brown, red, or even black.
Overall, the formation of dripstones is a complex process driven by the interaction of water, limestone, and atmospheric gases over extended periods, resulting in the spectacular geological features found in caves and other underground landscapes.
In the Grič tunnel you can see dripstones at many places throughout. Take a walk through and answer the questions:
- What is the color of dripstones here? Do you think they are pure or have some impurities?
- Describe the different formations of dripstones in the tunnel.
- Where do dripstones form the most? Why is it so?
- Attach a photo with some of dripstones.
[HR]
Mjesto je otvoreno svakodnevno od 9:00 do 22:00. Ulaz je besplatan. Radno vrijeme može varirati tijekom događaja u tunelima.
Kapnici, poznati i kao speleotemi, su geološke formacije koje se tipično nalaze u špiljama, rudnicima ili drugim podzemnim okruženjima, rezultat su prekristalizacije minerala koji se prenose kapljanjem vode. Distinguira ih jedinstvene oblike i strukture, uključujući stalaktite, stalagmite i stupove, koji se formiraju kroz složene kemijske procese.
Formiranje kapnika počinje interakcijom između vode i vapnenca, uobičajenog minerala u mnogim špiljama. Prvo, kišnica prodire u tlo, upijajući ugljični dioksid i organske kiseline dok se probija kroz tlo. Kada stigne do vapnenačkog podložnog stijena, kisela voda otapa kalcijev karbonat (CaCO3) (vapno) iz stijene, stvarajući otopinu poznatu kao kalcijev vodikov karbonat (Ca (HCO3) 2), koji je topljiv u vodi.
Kako ova otopina prodire u špilju, susreće otvore na stropu špilje, što joj omogućava da kaplje u pećinu ispod. Nakon izlaganja zraku unutar pećine, oslobađa se ugljični dioksid, što uzrokuje da se kalcijev vodikov karbonat preobrazi u svoj netopiv oblik, kalcijev karbonat (vapno). Ovo vapno precipitira iz otopine i postupno se nakuplja, formirajući karakteristične strukture kapnika tijekom godina.
Stalaktiti, koji vise s stropa špilje, formiraju se kada voda bogata kalcijevim karbonatom kaplje prema dolje, ostavljajući mineralne naslage s svakom kapljicom. Ove naslage se s vremenom nakupljaju, stvarajući izdužene, slične ledenicama formacije. Stalagmiti, s druge strane, formiraju se na podu pećine neposredno ispod stalaktita. Kada kaplja voda udara u tlo, oslobađa se ugljični dioksid, što uzrokuje precipitaciju kalcijevog karbonata. Tijekom vremena, ove mineralne naslage se nakupljaju, rezultirajući u stožastim formacijama koje se uzdižu prema gore s poda pećine.
U nekim slučajevima, stalaktiti i stalagmiti se mogu spojiti kako bi formirali stupove, poznate kao stalagmati. Ako voda ne kaplje već teče, može stvoriti različite stupove na zidovima pećine. Boja kapnika može varirati ovisno o mineralima prisutnim u vodi i okolišu u kojem se formiraju, rezultirajući rasponom nijansi od bijele i prozirne do različitih nijansi smeđe, crvene, ili čak crne.
Općenito, formiranje kapnika je složen proces koji pokreće interakcija vode, vapnenca i atmosferskih plinova tijekom dugog vremenskog razdoblja, rezultirajući spektakularnim geološkim obilježjima koja se nalaze u špiljama i drugim podzemnim pejzažima.
U tunelu Grič možete vidjeti kapnike na mnogim mjestima. Prošećite i odgovorite na pitanja:
- Koja je boja kapnika ovdje? Mislite li da su čisti ili imaju neke nečistoće?
- Opišite različite formacije kapnika u tunelu.
- Gdje se kapnici najviše formiraju? Zašto je to tako?
- Priložite fotografiju s nekim od kapnika.