Rocks of the Krkonoše Tundra

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Rocks and rocky outcrops are an unmis- extensive canyons, gorges, castellated takable part of a mountain range, even rocks, cliffs and castle koppies, as well though, according to their type, the char- as individual points of interest, such as acter of their geological development, waterfalls, caves, overhangs, rock towers representation and diversity of minerals, and pinnacles, balanced rocks and many climatic conditions, as well as various others. The rocks are also of importance local conditions, there are mountain for their connections with human activi- ranges which are rich in rocks, while ties, as people have long sought them others are poor. Rocky areas without out for building castles and due to their a cover of weathering products are not landscape dominance, for the construc- only a significant helper for geologists tion of various chapels, tourist chalets and geomorphologists who study these and last but not least, lookout towers mountains, but also play a fundamental and vantage points, often accessed by role for lay tourists and undemanding stairs, ladders, footbridges etc. visitors, because it is the quantity and shape of the rocks which are probably Krkonoše is a very old mountain range the most important factors in determin- and of course this also determines ing the landscape attractiveness of each its relief. Although there are certain region, i. e. its wildness and romantic exceptions, we can generally say that character. Of course there are mountain our developmentally younger moun- ranges with almost no exposed rocks, but tain ranges, where erosion is more they will never be as attractive for visitors rapid and contributes to the shaping as those ranges which are decorated by of the rocks, have a higher number of interesting rock formations. Even more rock formations than older mountain so, that they are very often connected ranges. Whatismore, neither the sedi- with other popular destinations, such as mentary rocks, such as sandstones,

Dívčí kameny Tor Rock basins are the most interesting microform on granite rocks (Pielgrzymy) conglomerates, dolomites and lime- are relatively easy to see from close up. stones (the local ones belong to the crys- After the forest is felled they are perfectly talline limestones, which we now include visible, even from a distance, and in the amongst the metamorphic rocks), nor case of extensive collections of outcrops, the young volcanic rocks, which cre- we can see them as a whole. However, ate the greatest number of rock forma- the critical period comes as the new tions, are represented here in Krkonoše. growth flourishes, as it often covers the Therefore, with a few exceptions, the rocks so completely that we can forget rocks in Krkonoše are not the dominant about trying to photograph them for the relief or landscape features, but on the next few years. other hand, there are plenty of rock formations here. The high percentage of for- Isolated granite rocks, tors and est cover is also a certain “handicap” for the rocks, because with the exception of castle koppies the mountain ridge rock formations, the great majority of the rocks here are par- These types of rocks are the most typi- tially covered, and the lower-lying rocks cal for the summit, or tundra areas of are completely covered, by forests. Of the Krkonoše, but even here they are not rocks which are located in the forests, so numerous. The majority of them are we can observe a kind of “three-phase found at lower, montane positions in the system” from the perspective of human mountain range, so are hidden in the life. If they are in a mature forest, they forests. On the other hand, it is clearly

4 l Rocks of the Krkonoše Tundra visible that in the colder periods of the and a number of Polish localities). Some Quaternary, most of these rocks also of the castle koppies in summit areas found themselves in places with a tun- could be transformed into tors (Svinské dra climate. kameny, Pielgrzymy).

At first we should explain the termino- The modelling of these types of rocks logical distinction between tors and is strongly influenced by the primary castle koppies. Genetically, the way in fracture system of the Krkonoše granite, which they were formed is the same, which formed during the solidification but they differ in the ratio between their and contraction of magma in the granite height and width (dimensions). With nar- massif already. Granite belongs to the row, tower-like tors their appearance is abyssal igneous rocks. Magma rising up clearly dominated by their height, but on from the Earth’s core was stopped deep the contrary, with castle koppies, often underneath the strata of older overlying with a quite irregular footprint, their area rocks (in Krkonoše these are schists: is the dominant feature. However, there mainly gneisses, mica schists, phyllites), are no binding criteria, so the distinction where it gradually solidified at depth is often a subjective one, and in fact, in and only emerged on the surface after many localities tors and castle koppies the erosional-denudational removal stand next to each other (Dívčí kameny of the overlying rocks. The German

The rocky outcrops in the Labské jámy cirques are the largest in the Czech Republic most important is exfoliation. Exfoliation fractures most commonly have an arched character and in places, where their sloping section emerges on the surface, they may conform with the slope of the valley or cirque, where they create extensive and smooth rock plates, which are sometimes mistaken for glacial polishing by the visitors (Velká Kotelní jáma Cirque, Navorské plotny in the Labský důl Valley, the upper part of the Důl Bílého Labe valley). The formation of exfoliation fracturing is explained by the unloading of the massif after the removal of the overlying crystalline rocks by erosional processes, as well as by climatic influences during the previous warm geological periods. Much more probable is a new theory, that they were already formed by primary (compres- sive) factors inside the granite pluton.

The largest tor of the Svinské kameny complex Opinions on the conception of these cliffs are not entirely unanimous. Some geologists and geomorphologists look geologist H. Cloos described the frac- at them only from the perspective of ture system of granite according to the their shape and apply these terms to three basic directions of fracturing and all isolated rock formations, emerging their German names as the LQS system. above their surroundings from all direc- L are bedding-parallel fractures, mostly tions. However, the predominant opinion horizontal or slightly inclined, Q are that only rocks which meet the criteria transverse, vertical (or steep) fractures, concerning shape, but mainly those roughly perpendicular to the main, which formed in a specific two-phase Silesian Krkonoše Ridge, and S are genesis, should be referred to in this longitudinal, vertical fractures, roughly way, is undoubtedly more correct. Even perpendicular to the Q fractures. This in this case, however, the opinions of results in ashlar- to cubic-shaped blocks the geomorphologists are not complete- of rock, which we can observe in various ly uniform: for example, the age of the modifications on most of the cliffs; in individual phases but also the effect of places where the L fractures predomi- the glacial periods (ice ages) on their nate, the blocks usually transform into formation are still being discussed. a more slab-like shape. However, this is the “ideal form”, which, under the influ- Their development already began in the ence of local conditions and second- warm and damp climatic conditions of ary fracture systems can change into the interglacials in the Early Quaternary a multi-directional fracture system. Of (Pleistocene), but according to some the secondary fracture systems, the experts this began in the Late Tertiary.

6 l Rocks of the Krkonoše Tundra The groups of rocks (castle koppies the whole rocky outcrop. In this case the or tors) represent the remnants of the fracture system played a very impor- original mass of the parent material, tant role: in general the outcrops with a more resistant core (usually in places dominant bedding-parallel horizontal or where it was harder and less fractured), sub-horizontal fractures were the most which formed underground during the resistant, because the least water pen- first phase of sub-surface weathering. etrated into them. For this reason they In the climate described, this took the have retained their pillar-like shape with form of intensive chemical weathering sharp sides, and almost without weath- of the rock (granites, which form the ering products at their foot (Svinské majority of Krkonoše, are especially kameny, Dívčí kameny, Słonecznik). susceptible to this), the result of which These rocks were later transformed by are fine-grained weathering products, weathering, including frost weathering, most commonly called coarse sand mainly in the form of rounding of the by laymen. In the second phase, after edges of individual blocks, which could the climatic changes and the onset take on the shape of an oven, or even of a temperate to cold climate, these a ball, or rarely, a false balanced rock or hard sections were exhumed, because a true balanced rock. the surrounding fine-grained weathering products (often coarse-sandy) were On the contrary, where the predominant rapidly transported away as a result fractures were vertical and sub-vertical, of mechanical removal, and the rock respectively where irregular fractures were formations began to emerge on the abundant, water penetrated the rocks surface, rising above the surrounding more easily and deeper into the massif, relief and landscape. However, in the and after it froze the rocks broke up most conditions of the ice ages (especially intensively and the destruction caused by the last one – called Würm) the rocks ice in the fractures was most rapid. The were – already completely exposed on most affected rocks almost completely the surface – further shaped, although disintegrated and became boulder fields, this was often in the opposite sense, or only small outcrops of the original rock i.e. leading to their destruction. Frost remained (Śmielec on the Polish side of fracturing advanced along the cracks the Silesian Ridge, and we cannot rule out induced rock disintegration of a variable that this was the case on Mt. Malý Šišák intensity, leading to the destruction of too), while in other cases only small cliffs

Various types of granite jointing can be seen in the Harrachova jáma Cirque Pančavská skála is the most perfect example of blocky jointing of granite

remained (Szrenica) and in further cases dead parts of lichens, algae etc), and a central “core” formation of varying size sometimes filled with water to different remains and is surrounded by boulder depths, although nearly always only sea- fields and talus piles at the foot (Violík, sonally. On the Czech side of Krkonoše Mužské kameny). they are quite rare, but the Polish part of Karkonosze is built predominantly of The youngest phase of weathering also granite and in the neighbouring Jizerské includes the formation of distinctive hory Mountains there are many more. microforms on the surface of the rocks, Their regular shapes, sometimes con- such as rock basins, “rock seats” (also necting to the drainage runnels, caught known as the Devil’s seats) and their people’s eyes long ago, and because drainage runnels and also rinnenkar- people were unable to explain their origin ren (also known as pseudo-lapiés), most by natural processes, they were consid- often running vertically. Particularly eye- ered to be the work of pagan ancestors catching features are the rock basins and that they served for sacrificial pur- (weathering pits): rounded (circular, poses. This is why they were also called ellipsoidal, rarely even lobe-shaped, and sacrificial bowls in the past; in German in the most advanced stages of devel- this has remained as a scientific or opment they may even join together), technical term until today (Opferkessel). bowl-shaped depressions, sometimes Today we know for sure that they are the partly filled with detritus (disintegrated work of nature. There are many theories rock), or even biogenic material (wind- concerning how they were formed, but we blown humus, leaves, etc, as well as still do not know the exact mechanism

8 l Rocks of the Krkonoše Tundra of their formation. It is most probable most commonly square in shape, look- that they were created polygenetically, ing like a cobblestone pavement. In under the joint impacts of mechanical, places where the dyke emerges longi- chemical, or most likely, by biochemical tudinally on the surface, different sized processes. According to some opinions, areas of this appearance are formed the selective weathering of the spheri- (Svinské kameny). cal formations of different compositions in the granite, the so-called schlieren, We can distinguish between three basic plays an important role. We can elimi- types of tors and castle koppies accord- nate climate change as the clear cause ing to their relief position. The most of their formation, because they occur dominant in the landscape are the sum- on cliffs both on the Krkonoše mountain mit tors and castle koppies (Svinské ridges, but also deep in the valleys. It is kameny, Violík, Dívčí kameny). Rocks of also difficult to explain the irregularity of the second type are also visible from afar their occurrence; on some cliffs there are as they stand on the edge of the slopes large numbers of them, but for example, (changes in gradient); most often where on the next cliff there are none. the summit levelled surface (etchplain) passes into the slope (Slonecznik, We must give a separate mention to the Harrachovy kameny). However, by far the so-called sliced cliffs, popularly known most numerous tors and castle koppies as pancake rocks, because they remind in Krkonoše are those on the slopes, us of a stack of pancakes. These are which also includes those on the crowns very densely dissected by horizontal of the inclined slopes of side ridges cracks; therefore the surface of the rock and ribs (in Czechia all of those in the has a thin plate-like shape. Atmospheric Mumlava valley and, with the exception weathering occurs more rapidly along the of Pevnost, even in the Sedmidolí valley, fissures and the rock surface is in effect and also the great majority of the numer- a structured network of parallel grooves ous outcrops on the Polish side of the and intermediate protruding plates. Their mountain range). formation was previously explained by the unloading of the rock mass during It is also necessary to mention that the erosional-denudational removal of granite tors and castle koppies are far the overlying strata, but this does not more numerous in the neighbouring explain why they only occur rarely and in Jizerské hory Mountains, which is logical a scattered distribution. However, accord- as that mountain range is mostly built ing to new research, we can assume that of granite. Today they are mostly in the the cause is different and relates to the montane zone, but from the perspec- primary fracturing of the rocks as a result tive of geological development and the of internal pressure. creation of rock formations, it is necessary to know that in the ice ages the On these rocks we can occasionally see whole of the Jizerské hory Mountains aplite rock tiles, or facets. Aplite is a dis- experienced tundra climatic conditions, tinctively light-coloured dyke rock, which just like those in Krkonoše. In terms of occurs in the granite quite often and is numbers of rock formations, the Polish similar in composition. In some cases side of Karkonosze, which is also mostly aplite is recognisable by its distinctive built of granite, is much richer than the character of cracking into small blocks, Czech side.

Rocks of the Krkonoše Tundra l 9 Svinské kameny (Trzy Świnki in Polish, 1,314 m)

This group of three summit, compact, them, there is a clearly visible aplite blocky tors along the line of the state dyke. Just below it there are three boul- border to the south of the summit ders, which were once connected to it, of Mt. Szrenica (Jínonoše) are the but have since completely broken off westernmost summit outcrops of this due to weathering. On these boulders type in the Czech Republic. The border we can see small areas of square aplite passes between them; the most dis- rock pavement. The Polish tor closer to tinctive tor with a double tower struc- the trail is 4–5 m high. Part of it con- ture stands on the Czech side, while tains thin horizontal fractures, which two smaller tors stand on the Polish form an imperfect “sliced” surface. side. The highest block, 8 metres high, It demonstrates a rather high level lies on the Czech side. The modelling of frost destruction and the boulders of the Czech tor is mostly due to the trapped in one of its crevasses form LQS fracture system, i.e. fractures in all an irregular, false perforated rock. The three directions. This contributed to the third outcrop, farther from the trail, is fact that its base is a castle koppie, but the lowest, most hidden in the pine its two towers have the appearance of scrub and also the most destroyed, tors. One of them is a perforated rock because it has the largest talus (rock window). In the lower block, next mounds below it, something which the to the lower section which separates other tors cannot match.

10 l Rocks of the Krkonoše Tundra

Szrenica (the older – rather obsolete – Czech name is Jínonoš, 1,362 m)

According to the extensive distribution a high exfoliation dome (inselberg). The of the rocky outcrops (on the western rocky outcrops which have survived are edge of the summit, on the crown of the low, not exceeding 5 m in height, and summit next to the chalets, called the are not very interesting. The largest of Szrenicka Skała and the most numer- them on the southern slopes are sur- ous are on the eastern to south-eastern rounded by contiguous dwarf pine scrub slopes), the summit of Szrenica was and no trail leads to them. Some of the probably originally a very large castle blocks of the Szrenicka Skała on the koppie. However, it is at an advanced summit have distinctly sharp edges. In state of destruction now and has trans- this case, however, this was caused by formed into an extensive boulder field. quarrying the rocks in connection with According to the distribution and posi- the construction of the chalet. The larg- tion of the slab-shaped boulders on the est and most complete boulder field lies southern edge of the crown, it cannot on the longest, north-eastern slope of be ruled out that the summit was once the mountain.

12 l Rocks of the Krkonoše Tundra

Końskie Łby (around 1,270 m)

A group of two castle koppies and there are only small talus piles at their two tors, which stands nearby, on the feet. On the contrary, the western rock northern slope of Szrenica, close to the outcrop with its arched surface and frac- alpine upper tree line. The majority of tures at its northern slope suggest that them feature blocky jointing, although this could be the torso of a low exfolia- in some sections the predominant fea- tion dome (ruwar), the southern half of ture is slab-disintegration. Weak frost which already succumbed to ancient, destruction has taken place here, so pre-glacial destruction.

14 l Rocks of the Krkonoše Tundra

Tvarožník (Twarożnik, 1,322 m)

This small summit tor stands directly on the state border, very close to the Czech- Polish Friendship Trail and around 400 m NE of the Vosecká bouda Chalet. The border line actually passes through the head of the highest block. It is not one of the largest tors, but has one of the most interesting shapes in all of Krkonoše. The untypical appearance of this formation, unlike any other tor, is partially due to the unusual dominance of bedding- parallel fractures, relatively steeply inclined to the NW, which creates “tilted”, but relatively thick slab-like blocks (more than 1 m thick). The destruction of the whole rocky outcrop progresses along these bedding-parallel fractures. The blocks which were broken off are further the tourist trail weathers more rapidly. transported down the slopes, forming This contributed to the formation of a low small boulder fields. Their most massive rock perforation (rock window), 2 m wide boulders are 5–6 m in length, undoubt- and up to 0.8 m high. On the side of the edly the largest in the surroundings of block forming its roof we can see rather any of the tors on the Krkonoše summit imperfectly developed rock facets. areas. The summit block, trapezoidal in plan view, 7×5 m in size and 1.3 m in At the bend in the trail below Tvarožník thickness, rests in a seemingly precari- there is another flattened (only 2–3 ous position on a small area, therefore m high) rocky outcrop, mostly hidden it is often wrongly referred to as a bal- amongst the dwarf pine scrub. It is inter- anced rock. However, it does not have esting for its very flat summit boulders, the ability to waggle and is only a false under which there is also a low rock win- balanced rock (only looks like a true dow. The small boulder field in its sur- balanced rock). A portion of densely frac- roundings provides evidence that most tured granite (total thickness only 20–50 of the original formation has already cm) in the lower part of the cliff face near disintegrated.

Rocks of the Krkonoše Tundra l 17 Sokolník (Sokołnik, 1,384 m)

A small and less attractive tor, situated position, as they broke off and fell into directly on the state border at the point the pile of weathering products. This where it changes direction. It is one of provides evidence that the destruction of the smallest tors, and even though by its the outcrop is of later, sub-recent date. genesis it belongs to tors, from a mor- Despite its imperfect shape, it is probably phological perspective it should really be the summit tor which is most “connect- called a rocky outcrop. Its dimensions ed” to the typical, hummocky, although are only 3 × 5 m with a height of 2.5–3.5 currently overgrown tundra soils, which metres. This formation is dominated by are found right next to it. horizontal bedding-parallel fractures, which is why each of the levels contain Sokolník is not accessible to the slab-shaped rocks and from the south public as it stands away from marked side they even form small overhangs hiking trails (although the trails – below the slabs. Unlike other tors with green-marked trail to the south and their surfaces of smooth fracture planes, red-marked to the north are less than the surface of the rocks here is rather 300 metres away). Its low height and uneven. The slab-shaped blocks which the surrounding dwarf pine scrub make were broken off form a narrow fringe at it almost invisible, which is why it is the foot and are mostly in an oblique unknown to most visitors.

18 l Rocks of the Krkonoše Tundra

Violík (Łabski Szcyt, 1,472 m)

The most dominant over the landscape their breakdown. The boulder fields and the second highest elevation of of differing widths which surround the a summit castle koppie in Krkonoše. It actual rocky outcrop show that in the stands directly on the state border, less ice ages the frost-weathering here was than 1 km NE of the spring of the Labe. exceptionally intensive. Other factors Its current knob-like appearance repre- which contributed significantly were its sents the castle koppies in an advanced exposed and extraglacial location, in stage of destruction, mainly due to frost- combination with the optimal orientation weathering processes. Today we could towards the predominant wind direc- say that it is mostly “buried” in its own tions. The head of the outcrop is very weathering products, as the massive rugged in a close-up view; this provides talus heaps, or boulder fields, at its foot evidence that the frost disintegration is hide the greater part of the knob and still in progress here, although of much reduce the height of its visible part. For less intensity than in the past. The most this reason the walls of Violík are only extensive talus pile lies on the NE side 5–6 m high. of the knob, and even shows signs of frost-sorting into the form of cryoplana- In the central part the preserved part of tion terraces. The Czech name Violík is the rocky outcrop was formed accord- probably derived from the widespread, ing to the distinctive granite fracture but untrue, story that “violet rocks” (the system, with predominantly vertical algae Trentepohlia iolithus), which were and very steep fractures. This explains previously a popular Krkonoše souve- why the disintegration of the tor was so nir, grow here. The completely different intense – because of the angle of these Polish name is simply derived from the fractures the water flowed extremely fact that the rocks stands close to the deep into the rocks and accelerated spring of the Labe.

20 l Rocks of the Krkonoše Tundra

Czarcia Ambona (Krakonošova kazatelna - Krakonoš’s Pulpit, 1,490 m); in Polish the name means Magic Pulpit)

These small, but compact and relatively them. As with the majority of castle low summit castle koppie (4–4.5 m) koppies with predominantly horizontal stands next to the telecommunica- fractures, there are no talus heaps at tions station (commonly called Wawel) the foot, and the base is well-defined, on the upper rim of the Śnieżne Kotły only with individual fallen boulders. Cirques. It stands near the state bor- However, the northern side of the rocks der, but on the Polish territory. These was artificially modified, walled in and rocks are dominated by horizontal bed- serves as a rest area for tourists. The ding-parallel fractures, which caused castle koppie itself is not particularly the flattened loaf-shaped appearance interesting, but it can boast of hold- of the individual slabs. Some of the ing a record. As it is part of the wider few vertical fractures have the form of massif of Mt. Vysoké Kolo, this makes fissures or crevasses; therefore, they it the highest-positioned castle koppie are filled with free boulders, which fell not only in Krkonoše, but in our entire from above and remained wedged into republic.

22 l Rocks of the Krkonoše Tundra

Harrachovy kameny (1,421 m)

Thanks to the easy access (less than All of the fractures of the LQS system 1 km on the flat trail from Vrbatova contributed to the modelling of these bouda Chalet), the Harrachovy kameny rocks, which is why blocky jointing rocks are well-known and attract many and disintegration predominates, but visitors, as the red-marked trail passes towards the slope on the eastern belt between them. Typologically they repre- of rocks, inclined exfoliation joints sent one of the least interesting outcrops begin to predominate; these are fully of granite castle koppies, and are also apparent further down the slopes of of small dimensions (both in area and in the cirque, where they form extensive height). They consist of two parallel belts rock plates. The atypical, “obliquely of rocky outcrops of 2–4 m in width and tilted” appearance of the perfectly only 1–2.5 m in height; the highest rocky angular highest cliff developed as spur is by the trail in the eastern belt and a result of S fractures, which are not only reaches 3 m in height. However, vertical here but sub-vertically inclined. these cliffs have never been much taller The block released along the fracture than they are now, as we can see from was then transported gravitation- the small or absent talus piles below ally down the slope. This also caused them, which rule out more extensive the fractures between the blocks to destruction of the rocks. They are typical open up, so that in several places the representatives of tors on relief breaks cliffs contain miniature rock windows. (slope breaks), in this case the Kotelní Transitional forms and microforms jámy Cirques. Despite their small size, are completely absent here. The cliffs the Harrachovy kameny hold one excep- are a popular vantage point over the tion: they are the only granite tors on the Kotelní jámy Cirques and lower-lying Český hřbet Ridge in Krkonoše, which is parts of western Krkonoše and the predominantly built of schists. Podkrkonoší Foothills.

24 l Rocks of the Krkonoše Tundra

Mužské kameny (Czeskie Kamienie, 1,417 m)

Although the Mužské kameny cliffs are is the rugged head of the rocky ridge. near neighbours with the Dívčí kameny The eastern wall of the castle koppie is cliffs on the main, Slezský hřbet Ridge, relatively compact and only has a nar- these two rocky outcrops were modelled row talus apron at its foot, but mov- in entirely different ways. The more ing southwards the disintegration is westerly Mužské kameny are the most stronger, making the talus piles wider perfect example of a monolithic castle here. The western side of the castle kop- koppie on the Czech side of Krkonoše. pie was subject to much more intensive While its upper end stands almost on destruction, which is why the talus piles the head of the ridge, its larger part with of chaotically piled boulders at the foot a length of almost 60 m and a width of are much bigger, and reach the same 12 m runs down the slope on the Czech height as the summit of the cliff at the side. The eastern wall reaches up to 14 southern end. m in height, making it one of the tallest castle koppies. Unlike the Dívčí kameny Directly next to the tourist trail on the with their predominance of horizontal Polish side, to the west of the main fractures, here the fractures in all three outcrop, there is a solitary, slender, directions are represented equally, 3-metre-high tor with a beak-shaped which caused the predominance of overhang at its head portion. Although it imperfectly blocky-jointed rocks. This stands nearby, its shape was controlled is also reflected in the effects of recent by platy jointing, which is reflected in its frost weathering, the result of which differing appearance.

26 l Rocks of the Krkonoše Tundra

Dívčí kameny (Śląskie Kamienie, 1,413 m)

This is the most perfect combination of group is more interesting and is prob- a castle koppie and a tor on the Slezský ably the most attractive cliff of this type hřbet Ridge. The main rocky outcrops in the Czech Krkonoše. The appearance now represent smaller castle koppies, of Dívčí kameny is strongly influenced by while the two separate pinnacles are the dominant horizontal fractures, mean- textbook examples of perfect tors. Their ing that platy jointing of the rock predom- position directly on the Czech-Polish inates. This is probably also the reason Friendship Trail on the mountain ridge why destruction due to frost weathering makes them a very popular tourist attrac- has not played an important role and why tion. Dívčí kameny consists of two groups there are no accumulations of weath- of rocky outcrops, of which the western ering products at the foot of the cliffs. group includes 4 individual cliffs (the Therefore, the cliffs have well-defined tallest reaches a height of 7 m); while bases. More extensive boulder fields can the eastern group has 2 cliffs (the taller be found further down the slopes, espe- of them is 5.5 m high). Thanks to its cially on the northern, Polish side. Dívčí more rugged relief, however, the western kameny is also one of the few summit

28 l Rocks of the Krkonoše Tundra castle koppies which contain several rock defined by vertical fractures. This cre- basins; the most visible is the vertically vasse is mostly covered from above by asymmetrical basin on the top of the a “lid” of another slab, also transported eastern outcrop. here by frost-weathering processes. This is how the cavity with smooth walls, The Dívčí kameny complex also includes reminding us of a grave, was created, or the so-called “Krakonošova hrobka maybe because it is only connected to -Krakonoš’s Tomb”, located several the ground by a small, rectangular open- metres from the trail around halfway ing. Human fantasy and its position on between the two main cliff groups. This the summits of Krkonoše only required is a very flat rock outcrop, consisting of the addition of the Giant Krakonoš. several slab-like blocks and boulders that were loosened by frost-weathering Lower down the northern slope, in the processes, with the help of fissure ice in middle of the boulder field, we can find the first phase of development, into the a smaller castle koppie called Małe form of a crevasse with straight walls Śląskie Kamienie.

Rocks of the Krkonoše Tundra l 29 Słonecznik (Polední kámen, 1,420 m)

This is the only significant tor on the of its head indicates the recent and summit areas of eastern Krkonoše, intensive frost weathering. Even though situated on the northern slopes of Mt. it is clearly a tor, it has a rather untypi- Smogornia a little to the west of the cal elongated footprint, reminding us Wielki Staw glacial lake. It is the most of the low torso of a wall. Its northern distinctive tor in a slope-break posi- edge is formed of a rock pillar, which is tion in all of Krkonoše, which makes isolated from the main body by a verti- it visible from a great distance and cal cleft, and reminds us of a human when viewed from the north it stands figure looking out over the landscape. high on the horizon in the line of the This is probably why the old legend con- midday sun. This is why it is named nected this tor to the giant Krakonoš; “Noon Rock”. It rises abruptly from the the rock should represent his palace, surrounding land and does not have an which he did not manage to complete apron of talus piles. The rugged nature before noon.

30 l Rocks of the Krkonoše Tundra

Větrný kámen (Wietrzny kamień)

This name cannot be found on any can be found on the upper surface of map, as it is a new and fresh name, the lowest part of the outcrop and has derived from the Větrný hřeben Ridge a circular shape with a diameter of 30 (Windy Ridge), on the lower end of cm and a depth of 12 cm. The bottom which it is located. It rises at the foot of the rock basin contains granite sand of Mt. Sněžka, on the rim of the Kocioł and airblown humus. Only 2 m from it Łomniczki Cirque. It stands 200 m from there is also a smaller and shallower the Dom Śląski building (by the former embryonic rock basin of the same Obří bouda Chalet) and is clearly visible origin. from the start of the trail to the summit. However, it does not attract the The majority of tors and castle kop- attention of many tourists, as it is only pies now stand at the montane level, an inconspicuous, flat castle koppie, so they are hidden in the forests, even the walls of which are only 2–3 m high. though they also developed under tun- It is fractured in a rather chaotic man- dra conditions during the cold periods ner, with a slight dominance of bed- of the Quaternary. Most of them stand ding-parallel fractures, which explains on the Polish side of the mountain the predominance of irregular slab-like range, although several can be found blocks and boulders. On the contrary, on the Czech side too, especially in the along with Dívčí kameny, it is the only Sedmidolí area. There are fewer tors, summit rocky outcrop in Krkonoše, in but reaching down to lower elevations, which a rock basin has developed. It in the Mumlavský důl Valley.

32 l Rocks of the Krkonoše Tundra

Rocks of the Pudlavský hřbet Ridge

Pudlavský kámen

Martinův kámen

The Pudlavský hřbet Ridge runs as a short slope spur from the southern slope of Mt. Vysoké Kolo and on the head of the spur there are 5 rocky outcrops of the tor or castle koppie types. They make up the largest such group of cliffs on the Czech side of Krkonoše.

The topmost-positioned and near- est to the Martinova bouda Chalet is the Martinův kámen, also known as Martinova skála. This is the most massive, tallest (up to 10 m) and most ruggedly dissected castle koppie. It is distinctively divided by horizontal, as well as vertical fractures, the combination of which created numerous steps and terraces overgrown with herb vegetation and trees, which reduces its attractiveness.

Martinův kámen Pudlavská skála

Pudlavská skála and Pudlavský Děravý kámen and Hlava (Rock kámen with Holes and Head Rock)

These cliffs stand near the upper logging These last two rock formations are road starting near the Medvědí bouda close to the lower logging road from Chalet. Pudlavská skála is a two-part, but the Medvědí bouda Chalet. Both of not very high (3–5 m) and flat cliff, with pre- their names are derived from their dominantly gently inclined bedding-parallel main characteristic. Děravý kámen is fractures. However, it is quite overgrown, the flat torso of a castle koppie, disin- which makes it less attractive. It is only tegrating in places into free boulders. more interesting when viewed from the The most interesting of them is the west, because it looks a little like a sphinx. lowermost part of the sphinx-shaped formation, which has a small rock win- On the other hand, the near Pudlavský dow at the point where the fractures kámen, right by the logging road, is the intersect. As a result of the irregular most dramatic and most striking tor on the weathering of the last pillar along the entire Pudlavský hřbet Ridge. It is a fully sub-horizontal fractures, an isolated isolated pillar-like formation, covering an block developed and stands above area of 6 × 5 m, and 6 m high. It was main- a narrower “neck” like a head. The ly modelled by the sub-horizontal fractures, whole of the castle koppie is named which also separate two of the rounded after this most striking and attractive summit blocks. formation.

Rocks of the Krkonoše Tundra l 35 Ptačí kámen (1,310 m; incorrectly also stated as 1,258 m)

The most typical slope castle kop- bedding-parallel fractures are pre- pie on the Czech side of Krkonoše dominant. With the exception of one is located on the south slope below tiny “devil’s seat” in a free boulder on Dívčí kameny, along the blue-marked the summit, there are no microforms trail from Petrova bouda Chalet to on these rocks. The north side of the Martinova bouda Chalet. As a whole outcrop facing the trail has suffered the it is shaped like a knob, compris- most destruction, with a small talus pile ing of two rocky outcrops. The main, of boulders at its foot. The second, more taller and more extensive castle kop- southerly outcrop is flat, only 1–2 m high, pie is broken up as a result of rather and most of it is hidden below dwarf advanced frost destruction. The walls pine scrub. From the main summit only reach a height of 5 m. Here the of Ptačí kámen there are attractive granite displays distinctive blocky views of the Sedmidolí valley and Mt. jointing, although the sub-horizontal Vysoké Kolo.

36 l Rocks of the Krkonoše Tundra

Pevnost (1,012 m)

This group of four granite castle koppies forests reduce their landscape signifi- stands on the hilltop of the same name at cance. This is a shame, because they are the end of the slope spur on the Slezský the best example of “sliced” cliffs, also hřeben Ridge. It stands directly above known as “pancake rocks”, on the Czech the Dívčí lávky Bridges at the conflu- side of Krkonoše. They are dissected by ence of the Labe and Bílé Labe streams. a dense network of horizontal fractures, These cliffs are not particularly tall (the only spaced 5–20 cm from each other. tallest is 5.5 m, the others only 3–4 m), Weathering advances more rapidly along but as they rise abruptly from the terrain these fractures, meaning that the walls of around, without talus heaps of weather- individual outcrops display whole systems ing products, they are a relatively promi- of weathered notches, separated by pro- nent landform. However, the surrounding truding ledges.

38 l Rocks of the Krkonoše Tundra

Pielgrzymy (Poutníci, 1,204 m)

On the Polish side of the mountain Czech-Polish Friendship Trail, which is range there are such large numbers used by many of our tourists. of rocky outcrops of the castle koppie or tor types that describing them all The Pielgrzymy group represents a com- would fill a separate book. Many of them bination of a castle koppie and a tor are also difficult to access for tourists, and reaches heights of up to 25 m. because no trail (marked or unmarked) It consists of three obliquely parallel- leads to them. Thus we will only mention positioned rocky outcrops, the slim one of them, which is not only the tallest heads of which resemble three human but is the most famous and is visible figures walking one behind the other. lower down the slope below Słonecznik This is probably how they got their name (Polední kamen), from the red-marked of “The Pilgrims”, or more probably it

40 l Rocks of the Krkonoše Tundra is because – thanks to the height of as well as their one-sided forms (rock their pillars – they have always stood seats or “devil’s seats”) and rinnenkar- prominently over the forest, unlike many ren. Some parts of their walls take other cliffs. Their original German name the form of sliced (pancake) rocks, Dreisteine (Three Rocks) was more apt. because they are strongly perme- ated with thick horizontal fracturing. The elongated base of all three cliffs is The rocks are characterised by weak primarily due to the effects of orthogo- frost-induced disintegration, which is nal granite tectonics. Unlike many other why they have sharply defined bases. rocky outcrops of this type, these cliffs Boulder piles or boulder fields, which also feature small microforms like rock accompany some of the other rocky basins and their drainage runnels, outcrops, are absent here.

Rocks of the Krkonoše Tundra l 41 Velká Sněžná jáma Cirque has the most isolated rock outcrops of all the cirques in Krkonoše

Rocks in the glacial cirques

The glacial cirques, or at least their upper individual cliffs, or more often it involves sections, rising above the alpine upper whole groups of cliffs with a greater vol- tree limit are a part of the mountain ume. Such processes are described as tundra. The numerous rocky outcrops, or rockfall. To a lesser extent the rocky out- even separate landforms, which emerge crops in the cirques are also shaped by from the slopes of the cirques, are mostly earth and snow avalanches, which can the results of glacial erosion (in the case also use their energy to tear off blocks of of Krkonoše, mostly glaciers from the rock. And of course biological weather- last, Würm glaciation), but processes ing, in which the root systems of dwarf during the post-glacial period (Holocene) pines and other woody plants disturb the also contribute to their current appear- rocks along fracture lines, also makes its ance. This mostly involves frost weather- contribution. However, due to the steep ing, which can be surprisingly intensive slopes of the cirques, most of the cliffs in the heavily waterlogged rocky cirques here only show one-sided faces and ter- and can cause the disintegration and raced steps. This implies that they lack tearing off of rocks, followed by their the isolation we know from other types of gravitational transport or falls of blocks. cliffs. As a result, these cliffs are rarely Gravitational transport can affect given individual names, or their names

42 l Rocks of the Krkonoše Tundra are only known to a small group of climb- the more southerly cliffs, which emerge ers. These cliffs, especially the orienta- from the cliffline from two, or even tions of the individual sections of their three, sides. From the north these are straight walls and the grikes that dissect the Ambrožova vyhlídka Viewpoint, them or separate them, are controlled by Pančavská skála Cliff next to the the orientations of tectonic structures. Pančavský vodopád Waterfall (this is Specifically, the dominance of transverse also the most perfect example of blocky vertical Q fractures takes control. This is jointing in all of Czech Krkonoše) and perfectly evident especially in granite, but the highest of them is Krakonošova unfortunately only from aerial photo- hlava (Krakonoš’s Head) near to the graphs. When moving through the terrain Harrachova jáma Cirque. it is not usually possible to see the cliffs as a whole; moreover, they are partly cov- The major part of the nearby Kotelní ered by vegetation. jámy Cirque is developed on the bedrock of schists (especially mica schists), the The most perfect examples on the properties of which are less favourable Czech side can be found at the head for the formation of more distinctive of the Labský důl Valley, on the cliffs in rock formations in the cirques. Here we the Velká Labská rokle Ravine and Malá can only find one, the Kotelský hřebínek Labská rokle Ravine below the Labský Ridge, running down the slope and divid- vodopád Waterfall, and especially on ing the Velká Kotelní jáma and Malá

The rocks on the Kotelský hřebínek Ridge are built of schists Granite tectonics greatly influenced the shape of the cirque cliffs (Velká Sněžná jáma)

Kotelní jáma Cirques. The landforms are cliffs. More distinctive, but still one-sided controlled by geological structures here, cliff faces are found in the Úpská rokle i.e. on the contrasting hardness and Gully below the Horní Úpský vodopád resistance of various rock types of rocks. Waterfall and in the trough called Žlab This is different from granite, where the Úpičky below the former Obří bouda most common deciding factor for the Chalet, but none of them are significant formation and appearance of cliffs is the enough to have their own local names. granite tectonics. In this case the control- But even here we can see from aerial ling structures are bodies of quartzite, photographs the same features we see in which resist erosion much more than the the Labský důl Valley, i.e., that the orien- surrounding schists, therefore they form tations of cliff faces are controlled by the convex relief elements and, in places granite tectonics. with intensive erosion, they also give rise to cliffs. The highest cliff faces of the The southern edge of the Úpská jáma Kotelský hřebínek Ridge dip towards the Cirque is formed by the Čertův hřebínek Velká Kotelní jáma Cirque. Ridge (1,418 m), which is a structural form similar to the Kotelský hřebínek In eastern Krkonoše a similar situation Ridge, and is built of hard quartzite exists in the Úpská jáma Cirque only. intercalations. In contrast to the localised However, in its granite part the more occurrence of quartzites in the Kotelní intensive and multi-directional fracturing jamy Cirques, here they form the larger of granite has a negative effect, which relief forms, the development of which is why there are no such perfect rock follows the contact zone at the border formations here as in the Labské jámy of the granite pluton and the Krkonoše Cirques, where the perfect blocky jointing Crystalline Complex. They were already leads to the formation of more distinctive formed in the Palaeogene period and cliffs. Therefore, the Studniční stěna and represent one of the most important Úpská stěna rock formations are typified building elements of Krkonoše, which only by rocky slopes, rather than actual has influenced the further development

44 l Rocks of the Krkonoše Tundra Rocky outcrops in the Mały Staw Cirque

and appearance of the entire mountain erosion along the fracture planes and range. The Čertův hřebínek Ridge is one their exposure. The most extensive of these elements. cliff is called Grzęda (its Czech name means “roost”) which separates the Cliffs within glacial cirques can, how- two cirques and follows a harder por- ever, also be found on the Polish side of tion of the granite. Several imperfect, the mountain range. The most distinc- but very distinctive rocky ridges, which tive of these are in the Śnieżne Kotły are sufficiently isolated that they have Cirques, which are the rockiest cirques been given individual names (Turnia in all of Krkonoše, with the highest cliffs, Popiela, Ząb Rekina, Suche Baszty, Maly which are vertical in places. The reason Ganek etc.), divide up the slopes of the why these exceptionally rocky slopes Wielki Śnieżny Kocioł Cirque. They are were formed here is due to the proper- separated from each other by rock cuts ties of the local granite. In contrast to and grikes, which also have individual the dominant horizontal fracturing of names and contain clearly visible evi- the Czarcia Ambona (Devil’s Pulpit) tor, dence of sub-recent to recent stream which only stands a little higher, the erosion in the form of torrential rain granite here has a dense network of runoff channels. vertical fractures of Q and S strikes. This combination allowed the exceptionally Distinctive forms of this type on the rapid progress of frost weathering, as Polish side also include the rocky ridge well as erosion by water flowing down which divides the Kocioł Wielkiego from the plateau above the cirque. Stawu and Kocioł Małego Stawu These processes split the cirque walls Cirques. This is basically a structural into a series of comb-shaped to slab- landform too, as it developed on the shaped rocks, reminding us of short hard dyke of porphyritic, fine-grained rock walls. Their cliff faces also display granodiorite (previously known as gran- “smooth” sections of various sizes, ite porphyry) and follows its strike for its which were created by the advance of entire length.

Rocks of the Krkonoše Tundra l 45 Basalt Gully (on right) and basalt outcrops in the middle foreground

Volcanic cliffs of the Krkonoše tundra

For this case we could write in the singu- faster erosion than the surrounding bloc- lar, because this type of cliffs only occurs ky-jointed granite. The dyke runs down in one place in Krkonoše, which makes the cirque slope perpendicular to contour it an exceptional case. Tiny intrusions of lines, and therefore precipitation waters neovolcanics (basalts of Tertiary age) can carved out a distinctive erosional gul- be found in many places in Krkonoše, ly, named after the rock type as the Żleb mostly on the territory of the granite plu- Bazaltowy or Basalt Ravine. Due to the ton, and especially on the Polish side, small area and extremely steep slopes as well as in several places around (the south slope is completely vertical in Harrachov. But they are so small that, with places) there are no separate, isolated the one exception, they do not form any rock formations here. Basaltic columns separate landforms and the great majori- exposed in the sides of the ravine were ty of them are hidden under the cover of formed by the cooling and shrinkage of weathering products, as well as vegetation. the magma. The trends of their long axes This exception is found on the western slo- are perpendicular to the cooling surface. pe of the Mały Śnieżny Kocioł, where basalt is found at an elevation of 1,425 m, which The Basalt Ravine is best known as one is clearly at a “tundra” altitude. It repre- of the most important botanical loca- sents the highest emergence of neovolca- lities, with the highest species diversi- nics not only in Krkonoše, but in all of cen- ty in all of Krkonoše. This is because the tral Europe. This position on the slope of basalt and its weathering products are the cirque could be included in the previ- basic and rich in mineral elements in ous groups, but genetically it is so diffe- comparison with the surrounding extre- rent, that it represents a separate “unit”. mely nutrient-poor granite or crystalline bedrock. Therefore, they provide habi- Due to the considerably more inten- tats for a range of rare plants, including se fracturing, basalt (which is otherwi- endemics, or those which can be found se a hard rock) is subject to significantly only here in all of central Europe.

46 l Rocks of the Krkonoše Tundra

Janova skála

Cliffs of structural origin and frost-riven cliffs

Structural landforms are defined as those in the surroundings of Janské Lázně), but relief shapes which formed as a conse- also orthogneiss (scattered over multiple quence of the contrasting hardness and localities). resistance of the various types of rock. Of course, this also concerns the cliffs Cliffs of this type also have close relation- in which the portions of harder rock are ship to frost-riven cliffs, as they were more resistant to erosion and denudation, shaped by frost processes in the ice ages therefore during the geological develop- too. There are also many cases where ment they have remained in raised posi- the rocks belong to both categories, i.e., tions above the surrounding less resistant they are of a primary structural genesis, and more rapidly eroded rocks. We know but underwent secondary and very inten- of many such examples from Krkonoše, sive shaping into the form of frost-riven but most of them are at lower elevations, cliffs. These are most common at lower or directly on the valley slopes. In sum- elevations, for example, on the slopes of mit positions, where tundra conditions the main Krkonoše valleys (most of all prevailed during the history of this area, in the Jizera River and Jizerka Stream the occurrence of such rocks is restricted. valleys, but we can also find them in the Most often they are bound to the musco- valleys of the Labe, Úpa and Malá Úpa vitic quartzites (especially in the contact rivers). However, their landscape-forming aureole, i.e. in the line of the Český hřbet role is limited, because they are strongly Ridge in the highest parts of Krkonoše), influenced by the schistosity of the rock. sericitic quartzites (most commonly in the This means that these cliffs and their fac- Jizera River valley around Rokytnice and es are usually extremely rugged, divided

48 l Rocks of the Krkonoše Tundra by numerous terraces and steps, often built of hard quartzites of the contact with humus and vegetation cover, so very aureole. Even though they are also low, few of them develop into high cliff faces mostly less than 5 m, unlike the previ- and even fewer into isolated or pillar- ous rocks, they are more distinctive in shaped landforms. With a few exceptions the relief. It is these rocks which form (such as the Bártlova skála and Emin the most rugged part of the summit kámen cliffs in the Labe River valley) they area of the Kozí hřbety Ridge, which, do not include formations which attract thanks to such rocks, has a roof-like tourists and for this reason there are usu- appearance. They are also the fun- ally no tourist trails leading to them and damental reason for the Kozí hřbety visitors do not search them out. Another Ridges being one of the most alpine- negative factor is that the great majority type (i.e. similar to the high mountains) of them are hidden in the forest, which landforms in the whole of Krkonoše. very often grows on the outcrops themselves, so that few of them offer attrac- The situation is more complicated in tive views, or only very limited views. the area of Krakonošova rukavice (the giant Krakonoš’s Glove), the fan-shaped In a similar way, some cliffs fulfil the closure of the Rudná rokle Gully on the conditions for cliffs in glacial cirques, SW slope of Mt. Sněžka. These areas but are also conditioned structurally. are also part of the contact aureole, For this reason, they have already been but here narrow belts of phyllites, mica described above as cliffs in glacial schists and quartzites alternate in rapid cirques (e.g. Kotelský hřebínek and succession, meaning that the slope is Čertův hřebínek Ridges). divided by low, down-slope elongated cliff series, emerging in stripes of harder From the perspective of the highest alti- rocks interspersed by narrow belts of tude, which fully reflects the current tun- rocky talus from the frost-destructed dra conditions, significant are the cliffs softer rocks. It is the only rocky terrain of structural origin on the slopes of Mt. of this type in all of Krkonoše, but the Železná hora, the western spur of the cliffs are so low, that they do not attract massif of Mt. Luční hora, towards the much attention from visitors. Hrazený důl Valley. The most distinctive of them is the down-slope rocky ridge Of the other cliffs of this type, i.e., locat- between the upper part of the Hrazený ed on a mountain ridge, but at lower důl Valley and the Železný žlab Gully. altitudes, we can also mention Janova They formed on hard quartzite intercala- skála (1,002 m) above Rokytnice nad tions of the contact aureole. Although Jizerou on a bedrock of sericitic quartz- from the climatic perspective, they fully ites, emerging sharply from the flat head meet the criteria for rocks in a tundra of the Čertova hora side ridge. It forms position, most visitors to the mountains a massive and compact, unilaterally do not even notice them because they sloping block, distinctively shaped by are low and inconspicuous, and also the inclined schistosity planes. hidden in the dwarf pine scrub. Close to Horní Mísečky we can find From the genetic perspective the east- a similar rocky outcrop called Harrachova ern half of the summit cliffs on the Kozí skála (1,035 m), which takes the form of hřbety Ridge are similar. They are also an asymmetric, knob-like, frost-riven cliff

Rocks of the Krkonoše Tundra l 49 Harrachova skála

on the edge of the flat head of the ridge very distinctively shaped by the schis- (on the slope break). It is an attractive tosity of the rock, which is why their example of the frost destruction, which upper edge is noticeably protruding. At has mainly affected the highest north- the base and in the near surroundings ern and eastern faces. Thanks to the we can find a small talus cone, which southerly dips of the schistosity planes, was created by the frost destruction to these faces represent its “forehead”, this outcrop and has a distinctly shingle- which is bordered by fracture systems. shaped arrangement of its tabular Small talus piles of angular blocks lay fragments. under the faces. Here we can clearly see the difference between the weathering of At an even lower altitude of around granite (forming larger and more angular 900 m we can find the Modré kameny boulders) and crystalline rocks (forming Cliffs above Janské Lázně. They consist smaller, often plate-shaped, fragments). of a group of six quartzite cliffs lined The summit with metal railings is a popu- in down-slope direction on the side lar vantage point with views of Špindlerův rib of Mt. Světlá hora. In accordance Mlýn and eastern Krkonoše. with the dips of schistosity planes in the rock, most of the cliffs have one Similar unilateral shaping can be seen gentle slope and a steep or vertical on the two low summit rocky outcrops face on the other side. The disintegra- called Tabule (Skalny Stół, 1,282 m), tion caused by frost weathering, mainly a part of the Střecha massif on the progressing along the steep to vertical opposite side of Krkonoše, above the fractures, in a very similar way to rocks Pomezní Boudy Chalet. However, only at higher elevations, is clearly visible, a resistant portion of mica schists is especially on higher outcrops. The talus involved here, and the term “cliffs” is piles to small talus fields at their bases only symbolic – their steep edge faces are also identical with those at higher north towards Poland, but only reaches elevations; they formed in periods of a height of around 2 m. The cliffs are cold climate.

50 l Rocks of the Krkonoše Tundra

Rocks of the Krkonoše Tundra

Published by the Krkonoše National Park Administration in 2016 Text: Vlastimil Pilous Photography: Kamila Antošová, Radek Drahný, Jiří Dvořák, Simona Macháčková, Zdeněk Patzelt, Vlastimil Pilous, Lubomír Sklenár

Printed on recycled paper.

ISBN: 978-80-7535-041-1

PILOUS, Vlastimil. Skály krkonošské tundry. Vrchlabí: Správa KRNAP, 2016. ISBN 978-80-7535-041-1. not for sale.