Naravni most in jama EarthCache
Hidden : 7/19/2019
Difficulty:
2.5 out of 5
Terrain:
3 out of 5

Size: Size: other (other)

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Geocache Description:


Naravni most in jama
Trnovski gozd sestavljajo planote Trnovski gozd, Nanos, Hrušica in Banjšice ter dolina Trebušnice. Celotno območje je pokrito 80 % z gozdnogospodarskimi površinami. Na območju Trnovskega gozda, Nanosa in Hrušice prevladujejo strnjeni gozdovi s posameznimi gozdnimi jasami, medtem ko so na Banjški planoti, Gori in v dolini Trebušice mozaično prepletajo kmetijske površine z gozdom. Dve tretjini površja Trnovskega gozda leži med 500 in 1000 m nadmorske višine.



Na severni strani je očitna tektonska zasnovanost ob dinarsko usmerjenem idrijskem prelomu, na jugu pa se kažejo rezultati tektonskega narivanja mezozojskih apnencev in dolomitov na mlajši eocenski fliš. V celoti dve tretjini površja pokrivajo apnenci, četrtino dolomit, ostalo pa fliš in nesprijeto gradivo.

Nad Lijakom, prav na prepadnem robu Trnovskega gozda, predira skalni pomol naravni most Skozno, isto ime pa označuje tudi spodmol oziroma kratko jamo. Približno 15 m dolg in okoli 10 m visok naravni most je nastal hkrati s spodmolom, saj je most le podaljšek oboka nad jamo. Le-ta je dolga okoli 15 m in ima zasigano dno. S skalnega pomola je izreden razgled na Vipavsko dolino in Furlanijo.

Domačini pripovedujejo, da je general Borojevič, avstrijski komandant Soške fronte, s Skoznega opazoval goriški del bojišča.

Apnenec je sorazmerno odporna kamnina, ki pa ima to lastnost, da ga voda raztaplja. Po nastalih razpokah pronica deževnica, ki spotoma topi kamnino. V smeri vodnih tokov počasi nastajajo rovi in dvorane, tako je nastala tudi jama in naravni most. Z raztapljanjem kamnine je jamski strop vedno tanjši in ta se lahko zaradi lastne teže nazadnje tudi poruši. To se je v daljni preteklosti dogodilo tudi tu.

Erozija je premikanje materijala zaradi vetra, vode, ledu, gravitacije ali delovanja živih organizmov, ki neprestano spreminja obliko zemeljskega površja. Sodi med eksogene površinotvorne procese, saj za razliko od endogenih (npr. vulkanski izbruhi) znižuje zemeljsko površje. Četudi erozija mnogokrat poteka s preperevanjem, je treba ta pojma razlikovati, saj slednji pomeni razpadanje kamnine in nastajanje prsti, prvi pa odnašanje prsti. Erozija je pomemben naravni proces, danes pa je mnogokrat povečan zaradi človekove aktivnosti in kot tak škodljiv; na tak način ga največkrat povzroča krčenje gozdov, prekomerna pašnja in gradnja prometnih poti. Problem erozije človek skuša odpravljati z gradnjo teras in pogozdovanjem.

Fizična erozija
Fizična erozija opisuje proces spreminjanja fizikalnih lastnosti kamnin brez spreminjanja osnovne kemijske sestave. Ti procesi povzročajo, da se kamnine razpadajo in drsijo po pobočju kjer se še bolj drobijo.

Rast rastlin lahko prispeva tudi k fizični eroziji v procesu, imenovanem bioerozija. Rastline razgrajujejo zemeljske materiale, ko se ukoreninijo, in lahko ustvarijo razpoke in razpoke v kamninah.

Vodna erozija
Tekoča voda je glavni povzročitelj erozije na Zemlji. Dež, reke, poplave, jezera in ocean nosijo velike količine materiala.

Erozija vetra
Veter je močan povzročitelj erozije. Eolski (vetrni) procesi stalno prenašajo prah, pesek in pepel iz enega kraja v drugega.

Erozija ledu

Led, ponavadi v obliki ledenikov, lahko erodira zemljo in ustvarja različne oblike. Na ledenih območjih in na nekaterih planinskih vrhovih se ledeniki počasi premikajo navzdol. Ko se premikajo, prenašajo veliko stvari med potjo, od drobnih zrn peska do velikih balvanov.

Za vpis zaklada, kot najdenega odgovorite na spodnja vprašanja in mi odgovore posredujete preko GC profila, vendar ni potrebno čakati na moj odgovor, da bi zaklad označili kot najden.
1. Poglejte naravni most in kratko napišite kako je nastal ter katera vrste erozije je vplivala na nastanek. Kaj mislite, da bo most stal večno ali se bo s časom spremenil?

Neobvezno:
1. Vpisu lahko priložite tudi fotografije.


Natural bridge and cave
Over the edge of the Trnovski forest, the natural bridge Skozno was created, and the same name also has cave here. About 15 m long and about 10 m high natural bridge was also created here. Bridge is only an extension of the the cave. Cave has about 15 meters. From the rocky pier is a wonderful view of the Vipava valley and Friuli.

A natural bridge is a rock formation where an arch has formed with an opening underneath. Natural arch is formed when inland cliffs are subject to erosion from weathering.

Natural arch is formed from narrow fins and sea stacks composed of sandstone. The formations become narrower due to erosion over geologic time scales. The softer rock stratum erodes away creating rock shelters, or alcoves, on opposite sides of the formation beneath the relatively harder stratum, or caprock, above it. The alcoves erode further into the formation eventually meeting underneath the harder caprock layer, thus creating an arch. The erosional processes exploit weaknesses in the softer rock layers making cracks larger and removing material more quickly than the caprock; however, the caprock itself continues to erode after an arch has formed, which will ultimately lead to collapse.

Erosion is the geological process in which earthen materials are worn away and transported by natural forces such as wind or water.

Physical Erosion
Physical erosion describes the process of rocks changing their physical properties without changing their basic chemical composition. Physical erosion often causes rocks to get smaller or smoother. Landslides and other forms of mass wasting are associated with physical weathering. These processes cause rocks to dislodge from hillsides and crumble as they tumble down a slope.

Plant growth can also contribute to physical erosion in a process called bioerosion. Plants break up earthen materials as they take root, and can create cracks and crevices in rocks they encounter.

Erosion by Water
Liquid water is the major agent of erosion on Earth. Rain, rivers, floods, lakes, and the ocean carry away bits of soil and sand and slowly wash away the sediment.

Erosion by Wind
Wind is a powerful agent of erosion. Aeolian (wind-driven) processes constantly transport dust, sand, and ash from one place to another.

In dry areas, windblown sand can blast against a rock with tremendous force, slowly wearing away the soft rock. It polishes rocks and cliffs until they are smooth—giving the stone a so-called “desert varnish.”

Erosion by Ice
Ice, usually in the form of glaciers, can erode the earth and create dramatic landforms. In frigid areas and on some mountaintops, glaciers move slowly downhill and across the land. As they move, they transport everything in their path, from tiny grains of sand to huge boulders.

Rocks carried by glaciers scrape against the ground below, eroding both the ground and the rocks. In this way, glaciers grind up rocks and scrape away the soil. Moving glaciers gouge out basins and form steep-sided mountain valleys. Eroded sediment called moraine is often visible on and around glaciers.

Other Forces of Erosion
Mass wasting describes the downward movement of rocks, soil, and vegetation. Mass wasting incidents include landslides, rockslides, and avalanches. Mass wasting can erode and transport millions of tons of earth, reshaping hills and mountains and, often, devastating communities in its path.

Here are the questions for logging this cache as found. Please send the reply through the contact form, but do not wait for my reply, log it right away.

1. Take a look on a natural bridge and shortly describe how it was formed and what kind of erosion created it. What do you think the bridge will last forever or will it change it's look over time?
Optional:
1. If you want you can make some photos and add them to your log.

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