Petanjska slatina EarthCache

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PETANJSKI VRELEC

Prekmurje je prava zakladnica lokalnih znamenitosti. Veliko je tudi malo manj znanih, za katere zelo verjetno še nihče ni slišal. Te majhne skrivnosti dajejo Prekmurju prav poseben čar.

Na Gornjih Petanjcih je več izvirov oziroma več slatinskih vrelcev naravne mineralne vode oziroma slatine, vsi pa se danes nahajajo na desni strani Mure. Nekoč so bili tudi na levi strani Mure vse do Murskih Petrovcev, a se žal niso ohranili. Najbolj znan med ohranjenimi je prav Voglerjev oziroma Petanjski vrelec. Zaradi visoke vsebnosti raztopljenih mineralov takšen vrelec imenujemo tudi slatina. Prvotni izvir je sicer zavarovan z ograjo, višek vode pa teče iz pipe, ki se nahaja za ograjenim vrelcem. Tu teče negazirana slatina, ki ima precej močan okus po železu. Razliva se v manjši bazen, ki je ognjeno rdeče barve, od tukaj pa po žilah odteče v reko Muro.

Domačini pravijo, da ni pravega špricerja brez petanjske slatine, ki se najbolje meša z domačimi suhimi vini. 

Beseda "špricer". Gre za tradicionalno osvežilno pijačo, zmešano iz belega vina in mineralne vode oziroma po domače slatine, ki se uradno imenuje brizganec. Besede ne boste našli ne v SSKJ-ju ne v Slovenskem pravopisu, a vsi vemo, o čem govorimo, ko rečemo natakarju: “En špricer, prosim.”

ZGODOVINA

Kot je zapisano na spletni strani Pomurskega muzeja, je bil Petanjski vrelec od leta 1868 v lasti bogate družine Vogler, njihova grobnica se nahaja na petanjskem pokopališču. Veleposestnika Josef in Hans Vogler, ki sta sicer stanovala v Radencih, sta bila lastnika Petanjske slatine, ki se je v takratnih časih imenovala Petanzer Saurebrunn. Domačini so vodo iz vrelcev v Petanjcih uporabljali že v 18. stoletju, šele takratne analize vode, ki so jih opravili na Dunaju, pa so pokazale visoke vsebnosti mineralov in ogljikovega dioksida.

Leta 1883 je vrelec najprej začelo izkoriščati podjetje Petanjska slatina v lasti Voglerjevih, slatinsko podjetje Petanjci pa je bila huda konkurenca radenski slatini, vse dokler se podjetji nista združili. Po koncu druge svetovne vojne, leta 1947, je bilo podjetje nacionalizirano in priključeno podjetju Radenska iz Radencev, ki je po drugi svetovni vojni postalo del splošnega ljudskega premoženja.

MINERALNI ALI TERMALNI IZVIR?

Petanjski vrelec spada med mineralne izvire. Mineralne vode so po definiciji tiste naravne vode, ki vsebujejo najmanj 1000 mg raztopljene trdne snovi in/ali 250 mg naravno raztopljenega CO2 v litru vode. Pravilnik o naravni mineralni in izvirski vodi (Ur. l. RS, št. 26/2000) poleg tega določa še, da ima naravna mineralna voda svoj izvor v podzemnem vodnem viru, je čista, ima lahko določene učinke, ki so ugodni za zdravje in izhajajo iz vsebnosti mineralov, elementov v sledeh ali pa drugih sestavin. 

Tako so mineralne vode razvrščene glede na katione: natrijeve, kalcijeve ali magnezijeve, ali glede na anione: kloridne, hidrogenkarbonatne, sulfatne. Če mineralne vode vsebujejo vsaj 1000 mg prostega raztopljenega CO2 na liter, jih dodatno imenujemo tudi kislice - kisle vode.

Kemijska analiza vode iz Petanjskega vrelca razkriva prisotnost različnih ionov, kar je ključnega pomena za razumevanje njenih lastnosti in učinkov. Kromatogrami so orodje, ki se uporablja za določanje koncentracij teh ionov v vodi. Na primer, vrhovi na kromatogramih kažejo na prisotnost specifičnih ionov in njihove koncentracije v vzorcu vode.

GEOLOŠKA PRETEKLOST 

Panonski bazen je obsežno območje, ki se je pred približno 17 milijoni let začelo naglo pogrezati zaradi dogodkov globoko pod Zemljinim površjem. Pogrezanje ni bilo enakomerno in ob prelomih so nastala manjša pogreznjena območja, ki jih imenujemo tudi sub-bazeni. Mursko-Zalski bazen, ki leži na zahodnem obrobju Panonskega bazena, združuje več manjših subbazenov, ki so nastajali sočasno.

Panonski bazen je nastal v osrednjem delu Centralne Paratetide, izginjajočega oceana, od katerega je danes ostalo le še Blatno jezero na Madžarskem. Panonski bazen je danes z vseh strani omejen s hribovji (Vzhodnimi Alpami, Dinaridi, Balkanom in Karpati), ki so kot kopna masa obstajali že v času pogrezanja. To je v grobem potekalo v dveh fazah.

PRVA FAZA POGREZANJA - PREDNEOGENSKA PODLAGA

Na jugu se je raztezala Jadransko-Dinarska tektonska mikroplošča (mikrokontinent Adria). Obsegala je približno območje nekdanje Jugoslavije, Albanije, zahodne Grčije, Jadransko morje in del jugovzhodne Italije. Adria se je južneje dotikala Afriškega kontinenta, na severu pa je obstajal Evropski kontinent. Med Adrio in Evropo se je še v kredi, za časa življenja zadnjih dinozavrov, raztezalo morje.

Zaradi vztrajnega pomikanja Afriškega kontinenta in obrobnih mikrokontinentov (tudi Adrie) proti severu se je ocean Centralne Partetide zapiral. Oceansko dno med celinama je proti jugu in jugozahodu tonilo pod Adrio, zaradi česar je nad tem območjem iz raztaljenih kamnin toneče oceanske plošče nastala vroča magma, ki se je dvigala proti površju. Ti vulkani so bili povezani z razpiranjem zemeljskega površja (rifting) podobno, kot se danes dogaja na območju vzhodnoafriškega rifta.

Vrste kamnin poznamo v glavnem iz vrtin, saj izdanjajo le na območju Pohorja. Osrednji del dna Mursko-Zalskega bazena je pravzaprav pogreznjen vzhodni podaljšek Pohorja. Zgrajen je iz metamorfnih kamnin (predvsem gnajsa, blestnika in amfibolita), ki lahko vsebujejo leče karbonatnih kamnin.

DRUGA FAZA POGREZANJA - MURSKA FORMACIJA

Pred približno 16 milijoni let je prvemu sunku pogrezanja sledila kratkotrajna faza stiskanja ozemlja, ki jo geologi imenujejo Štajerska orogenetska faza. Po njej se je naglo pogrezanje nadaljevalo in zajelo še širše območje. Zato najdemo morske sedimentne kamnine na zahodu vse do Moravč. Vemo tudi, da je bilo preko zahodne Slovenije Panonsko morje nekaj časa povezano tudi s tedanjim Sredozemskim morjem. V zaledju se je hidrografska mreža že močno razvila, zato je območje, začela preplavljati obsežna rečna delta, podobno, kot današnja delta Donave postopoma zasipava Črno morje. Reke so prinašale ogromne količine sedimentov z dvigajočih se Alp in jih odlagale v obsežni delti, od koder so jih turbiditni tokovi odnašali v globlje dele morja. Turbiditni tokovi so podvodni plazovi, ki s čela rečne delte odnašajo sedimente v globlje dele bazena. Na dnu bazena so se ti plazovi diferencirali, tako da se je najprej odložili debeleje zrnati material, torej pesek, nato pa vse drobnejši mulj. Ta, prostorsko dokaj omejena peščena telesa, so zaradi svoje dobre prepustnosti pomembni rezervoarji ogljikovodikov. Iz njih smo včasih pridobivali nafto, danes pa v bolj simboličnih količinah zemeljski plin in termomineralno vodo. 

Sčasoma je turbiditne sedimente prekrila proti jugu napredujoča rečna delta “Pradonave”. Tako so se ostali subbazeni v Mursko-Zalskem bazenu zapolnili že do konca pannonija oziroma pontija, pred približno 6 milijoni let. Delta se je pomikala še naprej proti jugu in do danes zapolnila tudi preostale dele Panonskega bazena.

Pogrezanje Panonskega bazena v osrednjem delu Velike madžarske nižine in na območju JZ Slovaške (Donavski bazen) sicer zamira, a poteka še danes. Pri nas, na zahodnem obrobju, se je pogrezanje končalo pred približno 6 milijoni let. Od takrat se zaradi vztrajnega približevanja Afrike in z njo tudi Adrie ozemlje Mursko-Zalskega bazena stiska in dviga.  Z nadaljevanjem dviganja ozemlja in nastopom ledene dobe (pleistocena) pred približno dvema milijonoma let so se hidrografske razmere na območju SV Slovenije spet spremenile. Sčasoma so privedle do porečij, kakršne imamo danes. Rečni sedimenti Drave, Mure in njunih pritokov predstavljajo zelo pomembne, a hkrati izredno ranljive vire pitne vode.

Petanjski vrelec se nahaja v Sloveniji, v regiji, ki je bogata z mineralnimi in termalnimi izviri. Podzemna voda v Murski formaciji je deževnica, ki se je infiltrirala v tla v pleistocenu, pred nekaj deset tisoč leti. Ta se je na svoji poti skozi podzemlje srečevala z različnimi sedimentnimi kamninami, ki jih je pod vplivom visokega tlaka in temperature tudi raztapljala. Tok v tej formaciji je zelo počasen, vendar regionalen, še vedno aktiven in celo čezmejen. Za doseganje temperature vode na ustju vrtin med 50 in 66 °C je potrebno izvrtati vrtine z globino nekje med 600 in 1600 m. Ta voda se pridobiva vse od Ptuja do meje z Madžarsko. V okolici Radencev se subtermalna voda pridobiva že na okoli 200 m.

NALOGE ZA VPIS GEOZAKLADA

Odgovore pošljite preko GC profila. Zaklad lahko brez čakanja na povratne informacije logirate. V primeru napačnega ali pomanjkljivega odgovora vas informiram. Vpisi ne smejo vsebovati odgovorov na vprašanja, prav tako pa ne smejo biti vpisani brez vnaprej poslanih odgovorov. Takšni odgovori bodo nemudoma izbrisani. 

1. V opisu si spoznal, da je vrelec zelo bogat z minerali. Kateri mineral, misliš, da daje vrelcu in strugi takšno barvo?
2. Prisloni roko k izviru. Je voda ledena, hladna, topla ali vroča? Na kakšen način bi lahko povišali njeno temperaturo?
3. Kateri pogoji prispevajo k boljši mineralni sestavi vode?
4. S pomočjo kromatograma v opisu poskušaj opredeliti mineralno vodo glede na katione.
5. Misliš, da voda iz Petanjskega vrelca vsebuje tudi CO₂? Če nisi prepričan, jo po želji lahko poskusiš. V primeru da ima kiselkast okus, potem je tvoj odgovor DA.
6. NEOBVEZNO! K vpisu priložite sliko sebe ali predmeta z vašim GC imenom in datumom obiska, vsekakor pa mora biti na fotografiji viden vrelec - za lepši spomin.

ENG

PETANJCI SPRING

Prekmurje is a true treasure trove of local attractions. There are also many lesser-known ones that probably no one has heard of. These small secrets give Prekmurje a special charm.

In Gornji Petanjci, there are several springs or carbonated mineral water springs, all located on the right side of the Mura River today. They once existed on the left side of the Mura up to Murski Petrovci, but unfortunately, they have not been preserved. The most famous among the preserved springs is the Vogler or Petanjski Spring. The original spring is fenced, and the excess mineral water flows from a pipe located behind the fenced spring. Here flows still mineral water with a rather strong iron taste. It pours into a small pool that is fiery red in color, and from here it flows through veins into the Mura River.

HISTORY

As stated on the website of the Pomurje Museum, Petanjski Spring has been owned by the wealthy Vogler family since 1868, and their tomb is located in the Petanjci cemetery. Landowners Josef and Hans Vogler, who lived in Radenci, were the owners of Petanjska mineral water, which was called Petanzer Saurebrunn at the time. Locals had been using the water from the springs in Petanjci since the 18th century, but it was the analyses conducted in Vienna at the time that revealed high levels of minerals and carbon dioxide.

In 1883, the spring was first exploited by the company Petanjska Slatina owned by the Voglers, and the Petanjci mineral water company was a strong competitor to Radenska mineral water until the two companies merged. After World War II, in 1947, the company was nationalized and merged with Radenska from Radenci, which after the war became part of general public property.

MINERAL OR THERMAL SPRING?

The Petanjci Spring is classified as a mineral spring. According to the definition, mineral waters are natural waters that contain at least 1000 mg of dissolved solids and/or 250 mg of naturally dissolved CO2 per liter of water. Additionally, the Regulation on Natural Mineral and Spring Water (Official Gazette of the Republic of Slovenia, No. 26/2000) states that natural mineral water must originate from an underground water source, be clean, and may have certain health benefits arising from the content of minerals, trace elements, or other components.

Thus, mineral waters are categorized based on cations: sodium, calcium, or magnesium, or based on anions: chloride, hydrogen carbonate or sulfate. If mineral waters contain at least 1000 mg of free dissolved CO2 per liter, they are also referred to as "acidic waters."

The chemical analysis of water from Petanjski Spring reveals the presence of various ions, which is crucial for understanding its properties and effects. Chromatograms are tools used to determine the concentrations of these ions in the water. For example, the peaks on the chromatograms indicate the presence of specific ions and their concentrations in the water sample.

GEOLOGICAL PAST

The Pannonian Basin is an extensive area that began to subside rapidly about 17 million years ago due to events deep beneath the Earth's surface. This subsidence was not uniform, leading to the formation of smaller sunken areas along faults, known as sub-basins. The Mura-Zala Basin, located on the western edge of the Pannonian Basin, encompasses several smaller sub-basins that formed simultaneously.

The Pannonian Basin emerged in the central part of the Central Paratethys, a disappearing ocean, of which only Lake Balaton in Hungary remains today. The Pannonian Basin is now surrounded by mountain ranges (the Eastern Alps, the Dinarides, the Balkans, and the Carpathians), which existed as landmasses during the subsidence period. This process broadly occurred in two phases.

FIRST PHASE OF SUBSIDENCE - PRE-NEOGENE BASEMENT

To the south lay the Adriatic-Dinaric tectonic microplate (microcontinent Adria), covering approximately the area of the former Yugoslavia, Albania, western Greece, the Adriatic Sea, and part of southeastern Italy. Adria was in contact with the African continent to the south, while the European continent existed to the north. A sea extended between Adria and Europe during the Cretaceous period, the time of the last dinosaurs.

Due to the persistent northward movement of the African continent and its peripheral microcontinents (including Adria), the Central Paratethys Ocean began to close. The ocean floor between the continents sank southwards and southwestwards under Adria, leading to the formation of hot magma from the molten rocks of the sinking oceanic plate. This magma rose to the surface, creating volcanoes associated with rifting, similar to the present-day East African Rift.

The types of rocks are mainly known from boreholes, as they only outcrop in the Pohorje area. The central part of the Mura-Zala Basin's floor is actually a sunken eastern extension of Pohorje, composed of metamorphic rocks (primarily gneiss, schist, and amphibolite) that may contain carbonate rock lenses.

SECOND PHASE OF SUBSIDENCE - MURA FORMATION

About 16 million years ago, the initial subsidence shock was followed by a brief phase of land compression, called the Styrian orogenetic phase by geologists. After this, rapid subsidence resumed, covering a broader area. Hence, marine sedimentary rocks are found in the west as far as Moravče. We also know that the Pannonian Sea was, for some time, connected to the then Mediterranean Sea via western Slovenia. An extensive river delta, similar to today's Danube delta gradually filling the Black Sea, began to flood the area as the hydrographic network in the hinterland became well-developed. Rivers brought vast amounts of sediments from the rising Alps, depositing them in the extensive delta, from where turbidity currents carried them into deeper parts of the sea. Turbidity currents are underwater landslides that transport sediments from the river delta's front to deeper basin areas. These slides differentiated on the basin floor, depositing coarser material (sand) first, followed by finer silt. These spatially confined sandy bodies are important hydrocarbon reservoirs due to their good permeability. They were once sources of oil and today produce natural gas and thermal mineral water in more symbolic quantities.

Over time, the advancing delta of the "Proto-Donau" covered the turbidity sediments moving southwards. Thus, the remaining sub-basins in the Mura-Zala Basin were filled by the end of the Pannonian or Pontian stage, about 6 million years ago. The delta continued moving southwards, eventually filling the remaining parts of the Pannonian Basin.

Subsidence of the Pannonian Basin in the central part of the Great Hungarian Plain and the southwest Slovakia area (Danube Basin) continues today but is diminishing. In our region, on the western edge, subsidence ended around 6 million years ago. Since then, due to the continued northward movement of Africa and Adria, the Mura-Zala Basin area has been compressing and uplifting. With the ongoing uplift and the onset of the Ice Age (Pleistocene) about two million years ago, hydrographic conditions in northeastern Slovenia changed again, eventually leading to the river basins we have today. The river sediments of the Drava, Mura, and their tributaries are crucial yet highly vulnerable sources of drinking water.

Petanjci Spring is located in Slovenia, in a region rich in mineral and thermal springs. The groundwater in the Mura Formation is rainwater that infiltrated the ground during the Pleistocene, tens of thousands of years ago. On its journey through the underground, it encountered various sedimentary rocks, dissolving them under high pressure and temperature. The flow in this formation is very slow, but it remains regionally active and even transboundary. To achieve water temperatures at the wellhead between 50 and 66 °C, wells need to be drilled to depths of between 600 and 1600 meters. This water is extracted from Ptuj to the Hungarian border. In the Radenci area, subthermal water is extracted at depths of around 200 meters.

TASKS TO LOG A EARTHCACHE

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1. In the description, you noted that the spring is very rich in minerals. Which mineral do you think gives the spring and stream such a color?
2. Place your hand near the source. Is the water icy, cold, warm, or hot? How could you increase its temperature?
3. What conditions contribute to a better mineral composition of the water?
4. Using the chromatogram in the description, try to identify the mineral water based on the cations.
5. Do you think the water from Petanjci Spring also contains CO₂? If you're not sure, you can taste it. If it has a sour taste, then your answer is YES.
6. OPTIONAL! Attach a photo of yourself or an object with your GC name and the date of your visit, but the spring must be visible in the photo - for a nicer memory.