Vjetrenica Cave EarthCache
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Vjetrenica Cave
Vjetrenica cave is located at the western edge of Popovo polje near the village Zavala in Ravno, Southern Herzegovina, 25 kilometers northwest of Dubrovnik, Croatia. The name of the cave means Wind Cave, the reason for this is immediately obvious, when you arrive at the gated entrance. In summer the wind blows rather strong, it can reach a speed of more than 15 m/s.
The existence of the cave is known for a very long time, it was already mentioned in 1461 on the Senat of Dubrovnik. Yet much earlier, Plinius the Elder (Gaius Plinius Secundus, AD 23 - 79) mentions in his work "Historia naturalis" a cave which is most likely Vjetrenica cave.
Vjetrenica cave is the largest cave system discovered in Bosnia and Herzegovina. It has been explored to a length of 7013,90 meters. 550 meters are open for visitors.
The air temperature in the cave is constantly 11,4 degrees Celsius, the temperature of the water 11,3 degrees Celsius. There are many galleries and corridors, lakes, waterfalls and numerous dripstones. Vjetrenica is one of the richest caves in therm of subterranean biodiversity. The cave also contains the bones of extinct animals, for example of the cave bear (Ursus spelaeus). More than hundred different species are registered in the cave, and about 37 were discovered and described in Vjetrenica for the first time. The amphibious cave salamander Proteus anguinus is the most well-known of the rare endemic species. It lives in the waters that flow underground through the limestone region. This animal is most notable for its adaptions to a life of complete darkness in its underground habitat. Its eyes are poorly developed and covered by skin. All its other senses are acutely developed. Proteus anguinus is thought to be the longest-lived amphibian species. The average total length of this species lies between 23 - 25 cm. Males are somewhat smaller than females. The front legs bear three toes, the rear legs two toes. There are three external gills on each side of the head.
Solutional caves
A solutional cave or karst cave is a cave usually formed in the soluble rock limestone. It is the most frequently occurring type of cave.
Bedrock is dissolved by natural acids like carbonic acid (H2CO3) in groundwater that seeps through bedding-planes, faults, joints and so on. Over geological epochs these cracks expand as the walls are dissolved to became caves.
The largest and most abundant solutional caves are located in limestone, but they can also form in other rocks including chalk, dolomite, marble, salt, and gypsum. Limestones caves are often adorned with calcium carbonate formations produced through slow precipitation. These includes flowstones, stalactites, stalagmites, helictites, soda straws, calcite rafts and columns. These secondary mineral deposits in caves are called speleothems.
Speleothems
The most common speleothems are stalactites, which occur in limestone caves. They form through deposition of calcium carbonate and other minerals, which is prepicitated from mineralized water solutions.
The chemical formula for the dissolving of calcium carbonate rock containing carbon dioxide forming a calcium bicarbonate solution in underground caverns is:
CaCO3 + H2O + CO2-> Ca(HCO3)2
This solution travels through the rock until it reaches an edge and if this is on the roof of a cave it will drop down. When the solution comes into contact with air the chemical reaction is reversed and particles of calcium carbonate are deposited:
Ca(HCO3)2-> CaCO3 + H2O + CO2
The average growth rate of stalactites is about 0,10 mm a year.
On the other hand, stalagmites are rock formations that rise from the floor of a cave due to the accumulation of material deposited on the floor from ceiling dripples. If stalactites, the ceiling formations, grow long enough to collect with the stalagmites on the floor, they form a column.
Soda Straws are very thin but long stalactites having an elongated cylindrical shape rather than the usual more conical shape of stalactites. Helictites are stalactites that have a central canal with twig-like or spiral projections that appear to defy gravity. Chandeliers or drapery are complex clusters of ceiling decorations. Flowstone is sheet like and found on cave floors and walls. Rimstone dams occur at stream ripples and form barriers that may contain water.
Your task to log this Earthcache as found:
Answer the following questions in your own words and send me the answers via message to my profile:
1.) What types of speleothems can be observed in the cave? According to the text above - explain how these speleothems were formed!
2.) When you stand in front of the cave's entry, you will feel something special - what is it?
3.) What is the most wellknown rare species living in the water basins of the cave?
4.) Except the cave bear, what was the most important found of a complete skeleton of an extincted species inside this cave?
5.) Optional: If you like, you are warmly invited to add a picture of you / your GPS at the location to the log! It is forbidden to take pictures inside the cave, so simply take a picture in front of the cave´s entry.
You can log immediately after you sent me the answers! There is no need to wait for a log permission! If there's something wrong, I'll contact you.
Špilja Vjetrenica nalazi se na zapadnom rubu Popovog polja u blizini sela Zavala u Ravno, i južnoj Hercegovini, 25 km sjeverozapadno od Dubrovnika. Ime pećine znači vjetar špilja, razlog za to je očita, kada stignete na Input ovisna. Ljeti puše prilično jak, može doći do brzine više od 15 m/s.
Postojanje špilje je poznat po jako dugo vremena, to se već spominje 1461 na Senat u Dubrovniku. Još mnogo ranije, Plinije stariji (Gaius Plinius Secundus, AD 23-79) spomnije u svom djelu "Histiria naturalis" špilja koja je najvjerojatnije špilja Vjetrenica.
Špilja Vjetrenica je najveći je sistem pećina otkriven u Bosni i Hercegovini. Istražen je u dužini od 7013,90 metara. 550 metera su otvoreni za posjetitelje. Temperatura u špilji je stalno 11,4 stupnjeva Celzija, temperatura vode 11,3 stupnjeva Celzija. Postoje mnoge galerije i hodnicima, jezera, slapove i brojine sige. Vejtrenica je jedna od najbogatijih špilja u therm podzemnih bioraznolikosti. Špilja također sadrži kosti izumrle životinje, na primjer
od špiljskog medvjeda (Ursus spelaeus). Više od stotinu različitih vrsta registrirani su u špilji, i oko 37 otkriveni su i opisane u Vjetrenica po prvi put. Amfibijski čovječja Proteus anguinus je najpoznatijih rijetke endemske vrste. Živi u vodama taj protok podzeman regijom vapnenca. Ova životinja je najviše ističe po svojim prilagođivanje na život u potpunoj tami u svoje podzemlje. Oči su slabo razvijene i pokriveni kožom. Sva njegova osjetila su izrazito razvijena. Proteus anguinus je mislio da se prenositeljem amfibija vrsta. Prosječna dužina ove vrste nalazi se između 23-25 cm. mužjaci su nešto manji od ženki. Prednje noge nose tri prsta, stražnje noge dva prsta. Postoje tri nanjske škrge na svakoj strani glave.
Krške špilje
Krška špilja je sekundarna špilja koja se nalazi u stijeni koju čine razne topive stijene vapnenca. Kišnica sadrži ugljičnu kiselinu (H2CO3) koja prodire kroz pukotine stijena i rascjepe u vapnenac i otapa vapno. Tijekom geoloških razdoblja šire se rascjepi i pukotine u stijenama i time nastaju špilje, posebno kad se u stijeni nađu i pomiješaju dvije različite zasićene otopine pri čemu nastaje nova koncentracija ugjličnog dioksida i time može dodatno otopit vapnenac.
Krške špilje su najčešći tip špilja. Uglavnom nastaju u vapnencu, ali ponekad i u kredi, mramoru, kamenoj soli ili gipsu. Krške špilje su često ukrašene sa predivnim naslagama kalcijevog karbonata. Polagano taloženja kalcita uzrokuje kapanje i spori protok vode koja je bogata ugljičnom kiselinom. Ti talozi se nazivaju sige, a u novije vrijeme navizaju se speleotemi, a to su saljevi, stalaktiti, stalagmiti, heliktiti, spageti, makaroni i špiljseke kaskade.
Speleotemi
Speleotemi ili špiljski minerali označuju se kao sekundarni mineralni talozi u špiljama. Najčešći speleotemi su sige, uglavnom se sastoje od minerala kalcita i argonita ili spoja kalcijevog karbonata. Pojednostavljena kemijska formula za otapanje kalcijevog karbonata (vapnenac) putem vode zasićene ugljikovom kiselinom, gdje nastaje otopina kalcij bikarbonata je:
CaCO3 + H2O + CO2-> Ca(HCO3)2
Ova otopina putuje kroz stijene dok nađe pukotinu kroz koju izlazi, ako se ona nalazi na strupu špilje ona će polako kapati. Kad otopina dođe u doticaj sa zrakom dešava se obrnuta kemijska reakcija i kalcij karbonat se taloži:
Ca(HCO3)2 -> CaCO3+ H2O + CO2
Sige rastu vrlo polako, točna brzina rasta siga ovisi o raznim faktorima kao kalcijeva koncentracija u vodi, sadržaju ugljičnog dioksida u vodi, količini vode i temperaturi. Prosječni rast jednog stalaktita je oko 0,10 mm godišnje. Stalaktiti su sige koje vise sa stropa i koje tako dugo kapaju i rastu dok ima dotoka vode. Pošto kapljice koje padaju na tjo još sadrže vapno, a koji se otpušta pri udarcu o tlo, rastu sa poda prema stropu stalagmiti. Stalaktiti i stalagmiti se mogu i spojiti i time onda stvore stup koji se naziva stalagnit.
Stalaktitne cjevčice "makaroni" su posebno tanke i duge sige. Naspram stalaktita koji su konusno oblikovani, pokazuju cilindrični presjek. Heliktiti su sige koje prkose gravitaciji i znaju rasti ponovno prema gore. Stropne sige, zavjese, draperije, saljevi mogu tvorit čitave ukrase špiljskog stropa i zida. Sige također mogu nastat i na špiljskom tlu kao špiljske splavi, konuliti, stalagmiti sa saljevom i špiljske kaskade. Sige mogu biti i raznih boja ovisno o otamanju minerala u vodi.
Da biste logirali ovaj keš, molimovas da mi svoje odgovore pošaljete putem message preko mog profila:
1.) Vrste speleoteme mogu biti u pećini? Prema tekstu - objasniti kako su nastale ove speleoteme!
2.) Kad stojiš ispred pećine ulaz, osjetit ćete nešto posebno - što je to?
3.) Što je većina ističe rijetke vrste žive u rezervoara vode u špilju?
4.) Osim špiljskog medvjeda, što je najvažnije postaviti potpun kostur ugašne vrste u ovoj pećini?
5.) Po želji, možete stavit u log sliku sebe ili svog GPS-a kod špilja!
Oprez: Nakon što ste poslali message, možete logirat jer log dopuštenje nije potrebno! Ako nešto nije u redu kontaktirat ću vas!
Have fun and enjoy!
Sources:
Goudie, M. P. (2014): Encyclopedia of Geomorphology.
Gunn, J (2004): Encyclopedia of Caves and Karst Science.
Hicks, F. L. (1950): Formation and mineralogy of stalactites and stalagmites.
Hill, C. A. & Forti, P. (1997): Cave Minerals of the World.
Moore, G. W. (1952): Speleothems - a new cave term. In: Nat. Speleogical Soc. News, Vol. 10(6).
www.wikipedia.org
All pictures were taken by the author.
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