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Vela spila je špilja smještena iznad grada Vele Luke na otoku Korčuli. Smještena je na padinama brda Pinski rat, na nadmorskoj visini od oko 130 metara. Špilja se sastoji od eliptičnog oblika kaverne koje mjere 40 metara dužine, 17 metara u visinu, i oko 40 metara širine. Postoje dva otvora na krovu špilje koja su nastala kolapsom svoda. Vremenski okvir nastajanja od ova dva otvora još uvijek neodređen.
Špilja se nalazi u uslojenim vapnencima kredne starosti, oblika je ovalne dvorane, duljine 50 m, širine do 30 m, sa 17 m visokim kupolastim stropom. Na stropu su dva prirodna otvora, kroz koje danje svjetlo osvjetljuje prednji i središnji dio špilje. Najniži dio dvorane 10 m je niži od razine ulaza.
Dno špilje ispunjeno je 4 m debelim naslagama, u kojima su nađene mnogobrojne kamene i keramičke izrađevine, ognjišta i vatrišta, kosti divljih i domaćih životinja i riba te nekoliko ljudskih ukopa, što upućuje na to da je služila kao ljudsko boravište od gornjega paleolitika sve do brončanoga doba.
Vrste špilja:
Krška špilja
Krške špilje su špilje koje se najčešće pojavljuju. Takve se špilje formiraju u stijeni koja je topiva; većina se javlja u vapnencu, ali se mogu formirati i u drugim stijenama uključujući kredu, dolomit, mramor, sol i gips. Stijenu otapa prirodna kiselina u podzemnoj vodi koja prodire kroz slojeve, rasjede, spojeve i slične značajke. S vremenom se pukotine povećavaju i postaju špilje i špiljski sustavi.
Najčešće se krške špilje nalaze se u vapnencu. Vapnenac se otapa pod djelovanjem kišnice i podzemne vode nabijene H2CO3 (ugljičnom kiselinom) i prirodnim organskim kiselinama. Proces otapanja stvara osebujni oblik reljefa poznat kao krš, kojeg karakteriziraju vrtače i podzemna drenaža. Vapnenačke špilje često su ukrašene formacijama kalcijevog karbonata koje nastaju sporim padalinama. Tu spadaju kamenčići, stalaktiti, stalagmiti, heliktiti, slamčice sode i stupovi.
Primarne špilje
Špilje nastale u isto vrijeme kad i okolne stijene nazivaju se primarnim špiljama. Lava cijevi nastaju vulkanskom aktivnošću i najčešće čine primarne špilje. Kako lava teče nizbrdo, njezina se površina hladi i stvrdnjava. Vruća tekuća lava nastavlja teći ispod te kore, a ako veći dio isteče, ostaje šuplja cijev.
Lava špilje uključuju, ali nisu ograničene na lava cijevi. Ostale špilje nastale vulkanskom aktivnošću uključuju, između ostalog, pukotine, kalupe lave, otvorene okomite kanale, inflatorne, mjehuriće i slično.
Morska špilja
Morska špilja vrsta je špilje nastala primarno djelovanjem valova mora. Primarni uključeni proces je erozija. Morske špilje nalaze se diljem svijeta, aktivno se formiraju duž sadašnjih obala i kao reliktne morske špilje na bivšim obalama. Neke špilje izrezane valovima isklesane su prije mnogo tisuća godina i sada se nalaze na 100 m ili više iznad sadašnje razine mora.
Komore morske špilje ponekad se uruše ostavljajući "obalnu vrtaču".
Zadatci za logiranje:
1. Odredite širinu i visinu ulaza u špilju.
2. Odredite vrstu špilje. Obrazložite.
3. Uz vašu prijavu priložite fotografiju Vas, Vašeg GPS-a ili nadimka napisanog na papiru, dlanu, majici i slično.
Odgovore pošaljite preko profila na geocaching.com, a NE u Vašem logu! Ne morate čekati na potvrđivanje odgovora. Jednom kada pošaljete odgovore slobodno logirajte pronalazak ovog EarthCachea. Ako odgovori budu pogrešni mi ćemo kontaktirati Vas.
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Vela spila is a cave located above the town of Vela Luka on the island of Korčula. It is located on the slopes of the hill Pinski rat, at an altitude of about 130 meters. The cave consists of an elliptical cavern measuring 40 meters in length, 17 meters in height, and about 40 meters in width. There are two openings in the roof of the cave that were created by the collapse of the vault. The time frame of the creation of these two openings is still undetermined.
The cave is located in layered limestones of the Cretaceous age, in the shape of an oval hall, 50 m long, up to 30 m wide, with a 17 m high domed ceiling. There are two natural openings in the ceiling, through which daylight illuminates the front and central part of the cave. The lowest part of the hall is 10 m lower than the level of the entrance.
The bottom of the cave is filled with deposits 4 m thick, in which numerous stone and ceramic artifacts, hearths and hearths, bones of wild and domestic animals and fish, and several human burials were found, which indicates that it served as a human residence from the Upper Paleolithic until bronze age.
Cave types:
Karst caves
Karst caves are the most frequently occurring caves. Such caves form in rock that is soluble; most occur in limestone, but they can also form in other rocks including chalk, dolomite, marble, salt, and gypsum. Rock is dissolved by natural acid in groundwater that seeps through bedding planes, faults, joints, and comparable features. Over time cracks enlarge to become caves and cave systems.
The largest and most abundant solutional caves are located in limestone. Limestone dissolves under the action of rainwater and groundwater charged with H2CO3 and naturally occurring organic acid. The dissolution process produces a distinctive landform known as karst, characterized by sinkholes and underground drainage. Limestone caves are often adorned with calcium carbonat formations produced through slow precipitation. These include flowstones, stalactites, stalagmites, helictites, soda straws and columns.
Primary caves
Caves formed at the same time as the surrounding rock are called primary caves. Lava tubes are formed through volcanic activity and are the most common primary caves. As lava flows downhill, its surface cools and solidifies. Hot liquid lava continues to flow under that crust, and if most of it flows out, a hollow tube remains.
Lava caves include but are not limited to lava tubes. Other caves formed through volcanic activity include rifts, lava molds, open vertical conduits, inflationary, blisters, among others.
Sea caves
A sea cave, also known as a littoral cave, is a type of cave formed primarily by the wave action of the sea. The primary process involved is erosion. Sea caves are found throughout the world, actively forming along present coastlines and as relict sea caves on former coastlines. Some of wave-cut caves were carved thounsands of years ago and are now found 100 feet or more above present sea level.
Sea cave chambers sometimes collapse leaving a “littoral sinkhole”.
Logging tasks:
1. Estimate the width and height of the cave entrance.
2. Determine the type of cave. Explain.
3. Attach a photo of you, your GPS or nickname written on paper, palm, t-shirt, etc.
Send answers via profile on geocaching.com, NOT in your log! You do not have to wait for your answers to be confirmed. Once you submit your answers feel free to log this EarthCache as found. If your answers are wrong we will contact you.