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<title>Cambridge Underground 1982: Expo Cave Development</title>
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<center><font size=-1>Cambridge Underground 1982 pp 15-20</font>
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<h2>CAVE DEVELOPMENT IN THE TOTES GEBIRGE, AUSTRIA</h2></center>
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<p><font size=-1>Webeditor's note: although this article expounds theories
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somewhat at odds with current thinking, it does have the one great advantage
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of having been written down and published, something which few of the more
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qualified club theorists have been able to achieve. It is thus included on
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the site for completeness, but should probably be taken with a pinch of
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salt.</font>
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<h3>INTRODUCTION</h3>
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<p>In reading through material related to this discourse I discovered
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reference to the writings of Cvijic, who had devoted considerable effort to
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the study of the extensive karst region of Jugoslavia, drawing certain
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conclusions as to the formation of that area, which I incorporate here as
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background to the area of Austria we have visited over the last few years
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considering its apparent similarities.
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<p>The basis for Cvijic's cycle of erosion requires three factors to be
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present: a thick and extensive mass of limestone, accompanied by an
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underlying impermeable rock for the initiation of a stream pattern.
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<p>"A study of the Totes Gebirge region (the Northern Limestone Alps), shows
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that it is composed mainly of Alpine Triassic and Jurassic (limestone),
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nonconformably overlain by paralic and largely detrital sediments of late
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Cretaceous and early Tertiary age (the Gosau Beds found in small scattered
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concentrations). The main elements of the Northern Limestone Alps are massive
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carbonate series of the Middle and Upper Triassic which may reach thicknesses
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of over one kilometre. Below and between the massive carbonate members are
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found thinly bedded series of shales and evaporites." The requirements seem
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amply fulfilled.
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<p>Cvijic's cycle then has three phases of development; in Youth the upper
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impermeable layer is removed by streams which then go underground through
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enlarged joints and fissures, the drainage pattern disintegrates, streams
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flow down normal valleys only to disappear into solution holes at blind ends.
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In Late Maturity the underground streams reach the impermeable underlying
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stratum and cavern roofs collapse, the limestone cover is reduced to a few
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outliers honeycombed with caves, and is finally removed.
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<p>In the area of the Totes Gebirge the Youth phase has been passed with
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almost no surface drainage now apparent, although
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<b lang=de>Sonnenstrahlhöhle</b> is an example of the result of a
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previous surface stream pattern which once flowed down a well defined valley
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into its impressive entrance chamber (partially collapsed). The surface is
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now generally composed of highly jointed limestone with no soil to prevent
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water from passing directly underground. How far the area has moved into the
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Mature stage is the question of greatest interest to the speleologist in the
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search for a deep system, a question which will be answered by continued
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exploration.
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<h3>DETAILED CONSIDERATION</h3>
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<p>In the two major systems discovered to date we have encountered the two
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forms of cave entrance in the shaft-like solution hole of
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<b lang=de>Eislufthöhle,</b> and the funnel-shaped depression of
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<b lang=de>Sonnenstrahlhöhle</b> (considered likely to be a top entrance
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to the <b lang=de>Stellerweg</b> system). In this context their relative
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positions on the massif are interesting (see <a href="tmmap.htm">map and
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section</a>). Returning to Cvijic's erosion cycle, the
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original surface stream pattern formed on an impermeable layer has, in the
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case of <b lang=de>Sonnenstrahlhöhle</b>, followed a well-defined route
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towards the edge of the massif where it has met a weak point in the limestone
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structure in the form of a slip fault. The angle of the passage in this cave
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and <b lang=de>Stellerweg</b> is similar (around 60 degrees from the
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horizontal) and conforms to the notion of water eroding along a line of least
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resistance, along this fault.
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<p>In the case of <b lang=de>Eislufthöhle</b> the situation is rather
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different (refer to <a href="tmmap.htm">map, section</a> and
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<a href="tmelev.htm">surveys</a>). The cave is situated roughly centrally in
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a depression surrounded on three sides by steep slopes - a depression of
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bare, heavily-jointed limestone. During the ice age this high ground would
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have been covered with a permanent ice field. In this situation the erosional
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processes would be concentrated under the snow allowing a depression to be
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formed, itself enlarged into a more circular plan by the action of ablation
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around its edges. As the depression begins to form its development
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accelerates as snow becomes more readily captured in it and its permanence
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becomes enhanced as its bulk reduces the effects of temperature fall. As
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opposed to the tremendous abrading of the valley glaciers, solution becomes
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the dominant erosional process as meltwaters flow under the ice searching for
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the easiest way down to the water table. Over long periods of time a cave
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system is formed draining the plateau.
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<p>The position of the water table then begins to affect the formation of the
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cave. As long as the water table is beneath the surface, water will percolate
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down along the easiest route, defined by the structure of the rock itself.
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The actual form of the water table will itself be dependent on the
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permeability of the rock - small and irregular joints will form the water
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table into a dome shape before the pressure of water is sufficient to produce
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lateral movement; conversely, if the joints have been enlarged by solution
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(ie. a cave system exists) the water will escape rapidly producing an almost
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flat water table.
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<p>In <b lang=de>Sonnenstrahlhöhle</b> there are four levels at which
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horizontal cave development has occurred. The entrance series results from
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the direct action of the surface water in its original pre-glacial pattern
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flowing into the fault and searching for the easiest way down. Down in fact
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to the second level of horizontal activity at around 1600 metres, at which
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level a large chamber with side phreatic passages has formed. This is the
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same level as the horizontal entrance series found in
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<b lang=de>Stellerweg</b> (see <a href="tmelev.htm">surveys</a>).
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<p>(It should be noted that the angle of the elevation for the 113 survey
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does not demonstrate the extent of the horizontal development. For a better
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picture see plan of 113, Cambridge Underground 1981.)
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<p>The series of shafts that dissect the horizontal route from above and
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continuing below, are the later routes formed by water percolating down from
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the denuded limestone surface to the much reduced water table below these
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abandonded upper phreatic sections. By this stage the surface drainage
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pattern has disappeared and the cave has become a collector of water from
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numerous sources rather than its original stream route. The horizontal
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phreatic tube 'entrance' to Stellerweg is a long-abandoned resurgence.
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<p>At 1600 metres, therefore, <b lang=de>Sonnenstrahlhöhle</b> has
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become a collector for waters searching for the water table which, following
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the advance of the neighbouring valley glacier, has been greatly lowered. The
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cave enters a vertical phase, a large shaft enlarged by spray action, until
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it reaches 1500 metres at a very jagged broken floor with an immature stream
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outlet and a small meandering phreatic tube opening once more onto an
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enormous shaft section - this has no apparent equivalent in
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<b lang=de>Stellerweg</b> (perhaps it can be attributed to a localised change
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in the character of the rock). The termination of the next vertical section
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is, however, directly reflected in <b lang=de>Stellerweg</b> at 1400 metres.
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There is considerable horizontal development in <b lang=de>Stellerweg</b> at
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this level which has not been explored as yet, but suggests the possibility
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of a link with <b lang=de>Sonnenstrahlhöhle</b> because of the abandoned
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phreatic development evident there also and an apparent continuation of that
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section, unfortunately blocked by boulders at present. The complex phreatic
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entrance series to 115 is also located at this level. This is obviously the
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level of the water table following the first major invasion of ice in this
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area. The large, now abandoned, phreatic cave passages developed during a
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period of stability during and after the retreat of the ice, emerging as
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tubes of varying sizes from the valley sides. These holes are, however, now
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perched several hundred metres up the sheer slopes. Following a further
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advance of the ice which brought about a further severe reduction of the
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valley floor and thus the water table, in Stellerweg and 115 we find a
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further phreatic level developed extensively at 1200 metres, at which a
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tortuous streamway meanders at a gentle incline before descending in a
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further series of pitches.
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<p>It is interesting to make a comparison between these closely related
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caves, and it is also interesting to note (see map, section and surveys) the
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apparent direct relationship of the development of
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<b lang=de>Eislufthöhle</b> to the features of the caves at the edge of
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the massif some two kilometres away to the north. It is clear that
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<b lang=de>Eislufthöhle</b> has a level of horizontal, if not distinctly
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phreatic, development at around 1400 metres - the same as in
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<b lang=de>Stellerweg</b> and <b lang=de>Sonnenstrahlhöhle</b>. If these
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levels defining stages of development of the caves correspond directly, the
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resultant very flat water table suggests a veritable network of caves sending
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water rushing away to the edges of the limestone. Further the level of the
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sump in <b lang=de>Eislufthöhle</b> compares with the phreatic level
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around 1200 metres in <b lang=de>Stellerweg</b>.
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<h3>CONCLUSIONS</h3>
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<p>The indications are that, considering its close proximity and similarity
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of development to <b lang=de>Stellerweg, Sonnenstrahlhöhle</b> should
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continue to a depth approaching that of <b lang=de>Stellerweg</b> and may
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well join it. The doubts raised are whether the next section, the first in
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fact in the cave, of wet and awkward streamway will lead to the head of a
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shaft, as has already happened in <b lang=de>Stellerweg</b>. Clearly the
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streamway does not end immediately as it did not back up in its constricted
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passage in flood conditions, and there was still a strong draught at this
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level. With progress down to this point being relatively straightforward, a
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further visit seems imperative.
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<p>The question of Eislufthöhle is an interesting one. Depending on the
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point of view, two different conclusions may be drawn: if the cave ends at
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1150 metres, the water table is domed and there will be no hope of deeper
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caves in that area. If the development of the cave is directly related to the
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falls in the water-table as seen in <b lang=de>Stellerweg</b> then the water
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table is very flat and further depth should be possible, the sump therefore
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being a perched one. Reference to the other major discoveries in the area and
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the levels at which they terminate (see surveys) suggests, tantalisingly,
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that it is only a question of finding a way through an apparent end, no
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matter how obscure (as demonstrated on two occasions in
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<b lang=de>Sonnenstrahlhöhle</b>). Other routes in
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<b lang=de>Eislufthöhle</b> have never been pushed to a conclusion, but
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will anyone ever go back?
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<p>Any comment on the state of <b lang=de>Stellerweg</b> may seem obvious,
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however it would seem likely that a further 200 metres should be added to its
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depth (down to the neighbouring lake level of 712 metres). The extent of the
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phreatic development threatens to be vast, the hillside quite honeycombed
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with cave passage (as predicted in Cvijic's erosion cycle). If the water
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table is flat, there should be passages heading away into the mountain,
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carrying the waters from the plateau.
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<p>Finally, the intriguing question of cave draughts often raised its head in
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discussion in Austria. Almost all the caves that we have explored in the area
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have had powerful draughts emanating from the entrance;
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<b lang=de>Sonnenstrahlhöhle</b>, however, had a distinct inward draught
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at the entrance, reverting to outward at around the 1600 metre level. In
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winter, the cave apparently sends clouds of snow billowing up from the
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entrance as the relatively warm cave air rises (as substantiated by our local
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contact on a ski trip). It would be expected that the other entrances draught
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inwards in winter as the air is drawn up through the cave system. The obvious
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conclusion is that <b lang=de>Sonnenstrahlhöhle</b>
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is the top entrance to the whole system. If this is the case and
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<b lang=de>Sonnenstrahlhöhle</b> can be connected to the
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<b lang=de>Stellerweg</b> system, there is the possibility of
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achieving a 1000 metre cave - unless fears of the cave joining
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<b lang=de>Nagelsteghöhle</b> prove justified.
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<h4>REFERENCES</h4>
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<p>Studies in Physical Geography, ed. K.J. Gregory, Dawson Publishing<br />
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Periglacial Processes and Environments, A.L. Washburn, Arnold<br />
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The Geology of Western Europe, M.G. Rutten, Elsevier<br />
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Jurassic Environments, A. Hallam, Cambridge Earth Science Series<br />
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Geomorphology and Climate, ed. E. Derbyshire, John Wiley and Sons<br />
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Weathering, Geomorphology, Text 2, C.D. Ollier<br />
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Structural Geomorphology, J. Tricart<br />
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Geomorphology, B.W. Sparks, Longman
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<p>For detailed surveys see Cambridge Underground from 1978 onwards, which
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will give more details of the caves mentioned above as well as other smaller
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discoveries.
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<p align=right>Tony Malcolm
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<hr />
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Link to <a href="https://en.wikipedia.org/wiki/Eastern_Alps">Wikipedia: Eastern Alps Geology</a>.
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<br />
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Link to <a href="geolog2.htm">Anonymous Geological Outline (2015?)</a>.
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<br />
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Link to <a href="years/1987/geolog.htm">Jared's Geological Guide (1988)</a>.
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<br />
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Link to <a href="years/1981/cavdev.htm">Tony Malcolm's Geological Guide (1982)</a>.
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<br />
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Link to <a href="https://onrappel.blogspot.com/2018/05/dachstein-massif-geology-intro.html">Excellent long article on Dachsteinkalk</a>
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<hr />
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</body>
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</html>
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