Geološka zgodovina v 7 kamnih / 7 Stones History EarthCache

(SI) Na zelenici pred Geološkim zavodom Slovenije, na Dimičevi ulici 14 v Ljubljani, je postavljena skulptura sedmih kamnitih plošč iz različnih vrst domačega naravnega kamna, ki v malem predstavljajo slovenske kamnine in našo geološko zgodovino.

(ENG) A sculpture of seven stone slabs, presenting seven typical Slovenian stones, is set in front of Geological Survey of Slovenia building in Ljubljana. Sculpture also represents geological history of Slovenia.

(ENG)BEFORE THE BEGINNING:
Visit our website Geološki zakladi / EarthCaches
for complete list of our EarthCaches and a lot of additional information.

SLOVENIA, A LAND OF SEDIMENTARY ROCKS

Only a brief inspection of the simplified geological map of Slovenia is enough to reveal the fact, that Slovenia is a land of SEDIMENTARY ROCKS. They form large portion of the land’s surface. Mountainous and hilly areas are mostly build from limestone and dolomite. They have formed in shallow seas, when substances dissolved in the water precipitated to the floor and formed chemical sedimentary rocks. Another source are water-dwelling animals and plants which extract dissolved mineral matter from the water to form shells and other hart parts. After the organisms die, their skeletons collect by the millions on the floor of ocean as sediment and form biochemical sedimentary rocks. In this way many fossil remains of animals and plants that lived during the formation of rocks have been preserved.
Lower hills, valleys and the plains are covered with another kind of sediment - deposits of gravel, sand, silt and clay. Material for deposits is a result of weathering processes of older rocks – of all types – igneous, sedimentary or metamorphic. These sediments (in time), through the process of lithification, form mechanical or detrital sedimentary rocks - conglomerate, breccia, sandstone and shale.
It is understandable that most of our masonry and other stone products are made of sedimentary rocks. Sedimentary rocks with visible fossil remains are especially valued.

IGNEOUS ROCKS, which formed from the magma under the surface, called intrusive igneous rocks, are only found on Pohorje mountains and in narrow belt in Karavanke mountains in Carinthia. The most known intrusive rocks are tonalite, which builds the belt in the Karavanke Mts., and granodiorite on Pohorje Mts. Extrusive igneous rocks, those that were formed after the magma* broke through to the surface, can be found on smaller areas in Jezersko, between Jezersko and Škofja Loka, near Idrijca, in Selška dolina and Bohor Mt. Majority of extrusive rocks lie south of the Karavanke Mts., on Smrekovec mountain and its wider surroundings. The most often used extrusive rock is actually a sandstone formed from the volcanic ash, called tuff.
*Note: magma are molten rocks under the Earth’s surface; magma that penetrates to the surface, is called lava.

METAMORPHIC ROCKS were formed by the transformation of igneous or sedimentary (or even older metamorphic) rocks under the influence of high temperature and pressure. Transformed rocks are found in areas surrounding igneous rocks on Pohorje Mts., on Kozjak Mt. and surroundings, and along the igneous rocks in Karavanke Mts. The most known metamorphic rocks in Slovenia are marble and slate.

The sculpture was designed by doc. Dr. Domen Zupančič from the Faculty of Architecture in Ljubljana. He and his team of students also helped in the final realization of the project. Students of the Stone Design Program from Higher Vocational School Sežana (within the Srečko Kosovel School Centre Sežana), with the support of the Higher Education Centre Sežana, have provided originally designed stone seats. The Secondary School of Civil Engineering, Land Surveying and Environmental Studies Ljubljana carried out the installation of a sculpture from the preparation of the foundation to the final arrangement of the surrounding area. Students of the Secondary Vocational and Technical School Bežigrad produced a metal sculpture framework, while students of Fran Milčinski Educational Institution Smlednik planted the greenery.

Stonecraft companies from Sežana, Povir, Hotavlje, Ljubljana, and Sečovlje responded to the invitation of Geological Survey of Slovenia and provided the stone slabs for the sculpture.

A significant part of the geological history of Slovenia is recorded in the exhibited examples of natural stone. Six of them are sedimentary rocks, only one stone is representing igneous rocks.

The oldest are two colourful examples of limestone from Hotavlje and Lesno Brdo quarries. They formed in the shallow sea in the Triassic, about 225 million years ago. Numerous monuments and architectural additions are made from those rocks. Polished to high gloss they show all the colourful beauty inside the important buildings in Slovenia and abroad. One of the famous objects made from Lesno Brdo limestone is the obelisk of the “Three Carniolan Rivers” fountain, at Mestni trg Square in Ljubljana (made by maestro Francesco Robba). More than 2000 square metres of Hotavlje limestone is used for pavements in the Ljubljana’s most important Cultural institution– Cankarjev dom.

Younger, about 93 million years old specimens of Repen limestone are from the surroundings of Sežana, from the Doline and Debela griža quarries. Because of the fossil shells caught in the rock, this is one of the most beautiful natural stones in southwestern Slovenia. It is also more resistant to weathering than other types of karstic natural stones, because of the dense (micritic) base. "Repen" is used in the landscape arrangement of Vipavski križ village, various traditional Karst products are made from it: containers, mortars, stands for cutting pršut (smoked ham) ...

The “fiorito” or “rosy limestone” comes from the quarry Lipica I. It was named after the flower-like cross-sections of fossil rudist bivalve molluscs, which inhabited the Tetida ocean in Cretaceous, more than 80 million years ago. Fiorato stone is used in many buildings, such as the Postojna Cave Entrance Station, hotels, markets. The products from this stone are very aesthetic, it is used for vases, stone containers, pillars.

The sixth stone, unlike the previous ones, is representative of the flysch layers of the sea basin 50 million years ago. These layers form large part of the Slovenian coast. The presented piece of flysch sandstone is from the quarry Elerji near Škofije.

The last, the youngest, "only" 19 million years old stone, is the hardest and therefore the most resistant to external influences. Stone is quarried on the southern edge of Pohorje Mts. in the Cezlak I quarry above Oplotnica. It is from the igneous rock that was created during the Pannonian basin expansion. People usually call it "granite" or "tonalite" form Pohorje, in the professional sense it is predominantly granodiorite with the transition to tonalite. The basic stone is cut by frequent light veins. Towns all around Slovenia are full of products from this granodiorite. It is used for stone coatings of more important buildings, for shelves, stairs, curbs, pedestals. Prior to the use of asphalt, it was a frequent choice for the paving of the city streets, and that centuries-old-decision still gives a typical image to the old town centres.

The EarthCache is freely accessible, placed along the sidewalk, next to street Dimičeva ulica. Access is quite simple if you arrive on foot or by bike. If you arrive by car, be aware that parking along-side of Dimičeva ulica is NOT allowed. I suggest you try to park at waypoint PARKNG, which marks the parking lot of the Geological Survey of Slovenia. Stop in front of the barrier and press the bell-button on the pillar. Kindly explain that you are there to see the stone sculpture, and that you will not park there for long time. The gatekeepers will let you to the parking lot, if it only wasn’t fully occupied.

LOGGING TASK
All the stones used in the sculpture are named in carving on the upright stone-slab. This carved inscription can help you find tasks solution. BUT, be aware, stones ARE NOT listed in the same order as they are set in the sculpture!
When answering, count stones from the one laying horizontally on the ground to the upright stone.
1. Find names of the two oldest rocks represented? Where are they standing in the line?
2. Where in the sculpture is the second-youngest stone? What rock is this and what kind of inscription does it carry?
3. Which stone would have been (more) damaged if you could rub together the first one and the fifth in the row? Explain your answer.
4. The sculpture is complemented by six beautifully designed stone seats. Describe the shape of the one you like best and try to figure out what kind of rock it is.

IMPORTANT!
- BEFORE LOGGING send answers through GC profile or directly to e-mail vane.si.geo@gmail.com
After that you can log - you don't need an additional permission to log. Please, only upload photos from afar!
- Logs without an previous e-mail with answers will be encrypted and later deleted!
- Logs containing answers will be deleted!

(SI)PRED ZAČETKOM:
Obiščite našo spletno stran Geološki zakladi / EarthCaches
za seznam vseh naših Geoloških zakladov in mnogo dodatnih podatkov.

DEŽELA SEDIMENTNIH KAMNIN

Že prvi pogled na poenostavljeno geološko karto Slovenije pove, da je Slovenija dežela SEDIMENTNIH KAMNIN, saj te sestavljajo velik del njenega površja. Gorati in hriboviti predeli so predvsem iz apnenca in dolomita. Ti kamnini sta nastali v plitvih morjih iz usedlin, ki so se na dno posedle iz snovi raztopljenih v vodi. Na ta način so nastale sedimente kamnine kemičnega izvora. Drugi vir so v vodi živeče živali in rastline, ki iz vode izločajo mineralne raztopine za gradnjo svojih skeletov, školjk in drugih delov organizmov. Ko organizmi odmrejo, se milijoni njihovih skeletov zbirajo na dnu morja kot usedlina, iz katere nastanejo sedimentne kamnine biokemičnega izvora. Na ta način so se ohranili številni fosilni ostanki živali in rastlin, ki so živele v času nastajanja kamnin.
Gričevja, doline in ravnine prekrivajo drugačni sedimenti - nanosi proda, peska, melja in gline. Gradivo iz katerih so ti sedimenti je rezultat preperevanja starejših kamnin vseh vrst - magmatskih, sedimentnih in metamorfnih. Ti sedimenti s časom tvorijo mehanske sedimentne kamnine - konglomerat, brečo, peščenjak, meljevec, glinavec in lapor.
Razumljivo je, da je tudi večina kamnitih izdelkov pri nas iz sedimentnih kamnin. Sedimentne kamnine z vidnimi ostanki fosilov so še posebej cenjene.

MAGMATSKE KAMNINE, ki so se iz magme strdile pod površjem, imenovane globočnine, najdemo samo na Pohorju ter na Koroškem v ožjem pasu - na območju med Peco in Koprivno na zahodu, do bližine Šoštanja na vzhodu. Najbolj poznani globočnini pri nas sta tonalit, ki gradi pas od Olševe do Zavodenj v Karavankah in pohorski granodiorit. Predornine, torej magmatske kamnine, ki so nastale po preboju magme* na površje, najdemo na manjših površinah na Jezerskem, med Jezerskim in Škofjo Loko, pri Stopniku ob Idrijci, v Selški dolini in na Bohorju. Največ prodornin je južno od Karavank, na Smrekovcu in širši okolici. Najbolj uporabljena predornina pri nas je tuf - to je pravzaprav peščenjak, ki pa je nastal iz posedlega vulkanskega pepela.
*Opomba: magmo, torej staljene kamnine, ki se prebijejo na površje, imenujemo lava.

METAMORFNE KAMNINE so nastale s preobrazbo magmatskih ali sedimentih (ali tudi starejših metamorfnih) kamnin pod vplivom visokih temperatur in tlakov. Takšne, preobražene kamnine, sestavljajo območja okoli magmatskih kamnin na Pohorju, sestavljajo gričevja Kozjaka in okolice, nekaj jih je še ob karavanških globočninah. Najbolj poznani in uporabljeni metamorfni kamnini pri nas sta marmor, ki je nastal iz apnenca ali dolomita in skrilavec.

Skulpturo je idejno zasnoval doc. dr. Domen Zupančič s Fakultete za arhitekturo v Ljubljani in s svojo ekipo študentov pomagal pri končni realizaciji projekta. Višja strokovna šola v okviru Šolskega centra Srečka Kosovela (program Oblikovanje kamna) iz Sežane je ob podpori Visokošolskega središča Sežana prispevala izvirno oblikovana kamnita sedišča. Srednja gradbena, geodetska in okoljevarstvena šola Ljubljana je izvedla postavitev skulpture od priprave temelja do finalne ureditve okolice. Dijaki Srednje poklicne in strokovne šole Bežigrad so izdelali kovinsko ogrodje skulpture, Vzgojno-izobraževalni zavod Frana Milčinskega Smlednik, pa je skulpturo ozelenil.

Povabilu Geološkega zavoda so se odzvala kamnarska podjetja iz Sežane, Povira pri Sežani, Hotavelj, Ljubljane in Sečovelj, ki so prispevala kamnite plošče za skulpturo.

V razstavljenih primerkih naravnega kamna je zapisan precejšen del geološke zgodovine Slovenije. Šest jih predstavlja sedimentne kamnine, le en kamen je iz magmatskih kamnin.

Najstarejša sta pisana primerka apnencev iz kamnolomov Hotavlje in Lesno Brdo. Nastajala sta v plitvomorskem okolju v triasu, pred okoli 225 milijoni let. Iz obeh so izdelani številni spomeniki in arhitektonski dodatki, vso pisano lepoto pa pokažeta polirana do visokega sijaja v notranjosti številnih reprezentančnih objektov doma in v tujini. Iz lesnobrdskega apnenca je najbolj znan obelisk Vodnjaka treh kranjskih rek (Robbov vodnjak), kiparja Francesca Robbe, na Mestnem trgu v Ljubljani. S hotaveljskim apnencem je obloženih več kot 2000 m2 površin v Cankarjevem domu.

Mlajša sta okoli 93 milijonov let stara primerka repenskega apnenca sta iz okolice Sežane, in sicer iz kamnolomov Doline pri Vrhovljah in Debela griža pri Povirju. Zaradi fosilnih školjčnih lupin, ujetih v kamnini, spadata med najlepše naravne kamne v jugozahodni Sloveniji, obenem pa sta zaradi goste (mikritne) osnove bolj odporna na vremenske vplive od drugih tipov kraških naravnih kamnov. »Repen«, kot mu pravijo, so uporabili pri krajinski ureditvi Vipavskega križa, iz njega izdelujejo različne tradicionalne kraške izdelke: posode, terilnike, stojala za rezanje pršuta…

Iz kamnoloma Lipica I prihaja rožasti apnenec. Ime je dobil po cvetovom podobnih presekih fosilnih rudistnih školjk, ki so pred več kot 80 milijoni let, v času krede, naseljevale tople plitve predele oceana Tetida. Uporabljen je v številnih objektih, na primer vhodni postaji Postojnske jame, hotelih, trgih. Izdelki iz tega kamna so zelo estetski, iz njega izdelujejo vaze, kamnite posode, stebre.

Šesti kamen je, za razliko od predhodnih, predstavnik flišnih plasti morskega bazena izpred 50 milijonov let. Te plasti grade velik del slovenske obale. Predstavljeni kos flišnega peščenjaka je iz kamnoloma Elerji pri Škofijah.

Zadnji, najmlajši, »le« 19 milijonov let star kamen, je najtrši in zato najbolj odporen na zunanje vplive. Izkopali so ga na južnem obrobju Pohorja v kamnolomu Cezlak I, nad Oplotnico. Je iz magmatske kamnine, ki je nastala v času razpiranja Panonskega bazena. Ljudje ga običajno imenujejo »pohorski granit« ali »pohorski tonalit«, v strokovnem smislu je to pretežno granodiorit s prehodom v tonalit. Osnovno kamnino sekajo pogoste svetle žile. Mesta po Sloveniji so polna izdelkov iz pohorskega granodiorita. Uporabljen je za obloge bolj reprezentančnih objektov, police, stopnice, robnike, podstavke. Pred uporabo asfalta je bil pogosta izbira za tlakovanje mestnih ulic, kar še danes daje značilno podobo starim mestnim središčem.

Zaklad je prosto dostopen, postavljen ob pločniku Dimičeve ulice. Dostop je povsem preprost, če pridete peš ali s kolesom. Če pridete z avtom, vedite, da parkiranje nikjer ob Dimičevi NI DOVOLJENO. Predlagam, da poskusite parkirati na točki PARKNG, ki označuje parkirišče Geološkega zavoda Slovenije. Ustavite pred zapornico in pritisnite gumb zvonca na stebričku. Prijazno povejte, da ste prišli na ogled kamnite skulpture, in da se ne boste dolgo zadržali. Z vratarji smo dogovorjeni, da vas spustijo na parkirišče, če le ni popolnoma zasedeno.

NALOGE ZA VPIS OBISKA
Na pokončnem kamnu so zapisane v skulpturi uporabljene kamnine. Zapisani podatki vam lahko pomagajo pri iskanju rešitev. A pozor: kamni NISO našteti po vrstnem redu postavitve!
Pri odgovorih kamne štejte po vrsti od ležečega proti pokončnemu kamnu.
1. Kateri sta najstarejši predstavljeni kamnini? Katera kamna po vrsti sta to?
2. Kje stoji drugi najmlajši kamen? Katera kamnina je to in kakšen napis nosi?
3. Kateri kamen bi se (bolj) poškodoval, če bi lahko podrgnil skupaj prvega in petega? Utemelji odgovor.
4. Skulpturo dopolnjuje šest lepo izdelanih kamnitih sedišč. Opišite obliko tistega, ki vam je najbolj všeč in poskušajte ugotoviti iz kakšne kamnine je.

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