O-157 UNDERGROUND STREAMS OF CRETE Chryssa Mavrokosta Speleological Association of Crete August 2005, Kalamos, Hellas

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1 438 found locally as the base of the High-Tatric thrusts sheets. Moreover these sheets contain at the base early Triassic siliciclastics and on the top middle Cretaceous marls forming aquicludes. In the Tatras and adjacent areas, an Eocene-Oligocene, siliciclastic flysch cover reaching over 3 km of thickness was deposited on the folded substratum. Since the early Miocene the Tatras have been cut by prominent faults on S and SE side, shifted to the N and asymmetrically uplifted c. 3,5 km. The strike of the thrusts and strata became roughly east-west and they dip to the north. The current relief of the Tatras is related to this Neogene uplift and erosion. River valleys dissecting the Tatras generally run perpendicular to the structures and are remodeled by Pleistocene glaciers. While most of the caves occur along the strike of narrow structural belts of carbonate rocks. The Lodowe Spring is discharging considerable part of the carbonate belt of the Czerwone Wierchy unit - the middle High-Tatric thrust sheet, in which occur the deepest and the longest caves of Poland: Wielka Śnieżna System (814 m of total denivelation and 22 km of total passage length), Śnieżna Studnia (763 m and 11 km respectively), Miętusia (292 m, 10 km), Ptasia Studnia (352 m, 6,3 km), Mała (538 m, 2,7 km), Czarna (303 m, 6 km) and Zimna (176 m, 4 km). New discoveries of very deep cave portions and observations of spatial cave pattern, passage morphology, paleocurrent directions (deduced from scallops), mineral composition of cave deposits and isotope dating of speleothems lead to revision of traditional interpretation of any roughly horizontal portion of caves as watertable caves correlated with river terraces, postulated subsequent glaciations and planation surfaces ascribed to the Neogene or Pleistocene according to present elevation above nearer principal valley bottom. Water tracing experiments in these caves show present vadose - phreatic discharge paths to the Lodowe Spring in the unglaciated portion of Kościeliska Valley. Probably, greater caves were developed along secondary porosity - bedding planes and fractures loosen during the Neogene uplift, because primary porosity and older fractures had been sealed by pressure solution and carbonate weinlets due to earlier compression and burial. Deep phreatic channels were developed several hundred meters beneath surface in whole thickness of carbonate sequences as concurrent outflow to contemporary incised surface valleys and beneath them. The greater caves exhibit a combination of two older broad roughly horizontal but evidently phreatic passages with multiple phreatic loops and the third active level. Many younger vadose shafts are connecting the valley slopes and bottoms with these horizontal caves and different cave horizons. These 3 principal horizontal phreatic levels with loops are: (1) at the elevation m a.s.l., c. 350 m above principal discharge point at Lodowe Spring represented by caves Czarna, Miętusia Wyżnia and upper horizontal portion of Wielka Śnieżna Cave system (about 300 m beneath bottom of principal glaciated Mała Łąka Valley; (2) at the elevation m a.s.l., c. 150 m above the same discharge point represented by middle horizontal portion of Wielka Śnieżna Cave, Miętusia and Zimna caves; (3) the lowest active level represented by explored by divers lower level of Wielka Śnieżna Cave (about 600 m beneath bottom of the Mała Łąka Valley!), water filled shafts in Miętusia Cave and present rising spring Lodowe. Vadose entrenchments are frequent but not deep in both upper levels. Dominant water flow directions deciphered on scallops marks western outflow to Kościeliska Valley similarly like present water tracing. Probably in the past these caves are portions of one cave system which was lowered gradually. The upper level was dewatered by rising spring at the entrance to Czarna Cave, the middle level in similar spring outflow from Zimna Cave. Uranium series dating of the speleothems (over hundred) show that caves of particular levels reached vadose condition: (1) the upper level before 1.2 My (Czarna samples), middle level and caves elevated only 40 m above valley bottom before 350 ky, caves in the active zone were already in periodic vadose condition since 200 ky. The vertical shafts ware developed as paths of water capture to lower level and as subglacial outflows. Complicated cave mazes near the valley slopes were developed as intermediate phases of cave system development during general outflow lowering before glaciations and during Pleistocene glaciations due to water paths blockade by glacier ice and permafrost. The mineral composition of cave loams in the upper cave level shows redeposition from surface of strongly weathered material in warm and wet climate Derived from different rocks, in the middle level rather local material is represented and below this level the weathering is weak and material is very diversified due to glacial transport from the higher part of the mountains. The age of upper cave level is probably of Miocene age, the middle level could be of Pliocene age, however the lower level must be older than middle Pleistocene. Pleistocene glaciers play strongly conservative role and diminished valley incision O-157 UNDERGROUND STREAMS OF CRETE Chryssa Mavrokosta Speleological Association of Crete Presentation on the 14th International Speleological Congress Athens, 26/8/2005 The topic of this presentation is Underground streams of Crete and it has to do with the results of the 3-year research of the members of the Speleological Association of Crete for the study of 5 caves that are functioning or used to function as underground rivers. Before proceeding with the presentation of the method that we followed, it is interested to mention that: - the final aim of the research was the writing of a book, which is about to be published; - the reason we chose the underground streams to be the topic of our research is because there is a plethora of studies concerning important archaeological Cretan caves, whereas very few people have dealt with the function and even more the anthropological dimensions of the underground karstic aquifers. The following criteria were adopted in order to choose between the various underground rivers that have been explored in Crete: - Their geographical dispersal in the Cretan island: they are located in all different mountains of Crete (fig. 1); - Their different function in relation to the water: 2 of them are rivers of a permanent flow, one has an occasional flow, another one is run by a seasonal stream and the last-one does not have any significant water flow being the upper karstic system of an extended aquifer of a whole region (fig. 2, 3). Having chosen the 5 rivers, which we will call from now on caves, we then had to choose the method that suited the best to the targets of our fig. 1

2 research. In the first place, we were interested in the speleogenesis procedure. However, already from our first observations it was clear that we had to start from outside of the caves. From the very beginning we realised that a cave and especially an underground river is a part of the erosive process that takes place in a further wider area than the one that is covered by the cave itself. It is wellknown that someone who chooses to study a part of a system is obliged to study the entire system in order to draw thorough conclusions. So, it was impossible for us to avoid regarding the 5 caves as vivid parts of the carstic aquifers as well as the grand relief, both of which were expanded in a range of several kms away from the sheer caves. Our speculation did not crop up only from the study of the speleogenesis of the specific underground streams but also from the realization that the way they might have been used by humans can not be detected if we do not go through the movements of the people on the natural scenery in which the caves belong to. In other words, in order to make reliable assumptions on the reason and the way people might have used the caves in the past, we had to study for example when and why they were obliged to pass outside their entrances. The prerequisite for this was the integration of each cave into a wider grand relief upon which the inhabitants used to move and act. Finally, all the above ended up to be a new proposal for the study of a cave. For us, this was a sheer experiment, with particular difficulties, but at the same time with a unique magic, especially because we started speculating not only on speleological but also on environmental and anthropological issues that are linked to the world of caves. fig. 2: VRISI -Lefka Ori: underground river with a permanent flow of water So we split the study into 2 main parts: 1. The first had to do with the outside of the caves: We called this study the study of the grand relief and we connected it with the human activities, the environment, the climate etc. 2. The second had to do with the inside of the caves. This was a sheer speleological approach, focusing on the physical description of the caves, the speleogenesis, their current function etc. Let s go through those two approaches The study of the grand relief : the outside of the cave We integrated the caves into a wider ecosystem in terms of geological and environmental characteristics. Aiming to detect the relationship that the inhabitants developed with the caves in the past, we went through the people s historical presence and activities. Within this framework, we divided the study into 2 parts: A) at first we set the boundaries of the area where the cave belonged to. The criteria were the movement of the surface water. Those boundaries are well-known as watershed and are the highest peaks of the water basin. In other words we firstly determined the area where the water which causes the karstification comes from and then we determined the area where this water ends to (fig. 4). Basically, the grand relief that is formed by the water movements is also the microsystem that the cave belongs to. The description of the grand relief follows. This description of the surface was considered to be crucial since it indicated the course of the water, disclosing at the same time the scenery of human activities. A part of this scenery is often the caves Then we proceeded with the short description of the other karstic phenomena of the area (caves, potholes, pits etc.) (fig. 6, 7). Furthermore, we provided information on the environment, meaning the natural resources such as the fauna and flora, the networks of the rivers and the streams, the climate, the land u=ses, the water-reserves. But why should we go through all those topics, which hardly seem to fig. 3: NERAIDOGOULA - Lasithiotika Mounts underground stream with an occasional flow of water fig. 4 14th International Congress of Speleology

3 help imminently the study of a cave? All the above provided us with information in order to approach anthropocentrically the cave, by seeking important issues such as the access of the grand relief, the trails, the passages, the roads and other communication diodes. The importance of the latter lies on the fact that they can reveal the access points to the caves. Furthermore, we proceeded with the so-called sight catchment analysis which focused on the influence of the humans over the landscape, as well as the reasons why they were using or they were not using them. Finally aiming to comprehend the historic use of the cave by the people of the area, we presented demographic and social data such the evolution and the spatial distribution of the population, the human activities in the present as well as in the past etc. B) At a second level, the information we provided is lying on the onthe spot observation, on conversations-interviews with the local people and on other bibliography that helped us to draw conclusions about the relationship between the inhabitants and the caves, which sometimes are consider by the former to be their property. We also elaborated on the toponomy, which is basically the human way to mark the landscape. A brief presentation of the distribution of the specific place-name in other caves in Crete follows. Some presumptions are presented on the different ways each cave was used and an effort was made to determine their utility potential. For example a narrow and elongated gallery could not be used as a devotional cave. Also a cave far away from the village was almost secluded, thus it could scarcely be used as a refugee for the people. The analysis of the outside of the cave closes with the cave in the human imaginary, providing the reader with legends and myths that escort every earthy phenomenon. fig.5 The grand relief of the area of Vrisi. LEFKA ORI fig.5 The grand relief of the area of Vrisi. LEFKA ORI The inside of the cave is the second approach of the study of the 5 underground streams This approach had to do with the shear speleological analysis, which was also split into 2 basic parts: 1. The first one was related to the study of the multidimensional function of the 5 underground rivers 2. The second one was related to the presentation of the above, in a comprehensive, but not a popular style. 1. Starting with the study of speleogenesis and the function of the caves, we tried to collect all the elements that would provide us with a thorough view of the morphology, the creation, the function, the life of each cave separately. At first, we gathered information from previous reports and other bibliography, we discussed a lot with the local people, and we came in touch with local authorities some of which had done geological studies in the past. Secondly we proceeded with the field work (exploration, topography and photography) which was the most time consuming and definitely the most demanding and difficult. In total we organized 43 expeditions where 800 hours of voluntary work were offered by the members of the Club in order to make the topography of 5.400m of galaries and narrow passages and take more than photos (fig.8,9). The lack of specialized biologists prevented us from studying the species, which was one of our targets at the very beginning. Only in one of the caves named Sarchos we managed to do a sampling of bats, with the cooperation and under the responsibility of researchers of the Natural History Museum of Crete (fig.10). Finally we forwarded with the synthetic evaluation of all the information gathered during the above stages and we attempted to come up with responsible presumptions for the speleogenesis of the 5 caves and for their fig.6 Other karstic phenomena in Tafkos area. Cave Fantaxospiliara

4 current function. This was extremely difficult, and we spent hundreds of hours discussing, studying and even quarrelling on the different theories. 2. Having finished with the above stage, it was a challenge for us to manage to present all the results in a way that would attract the reader of the forthcoming book. This effort was particularly difficult as the terminology used for the explanation -for example of the speleogenesis- is difficult to be simplified without changing its meaning, as we all know. On the other hand the bombardism of the reader with new vocabulary would definitely alienate him from the book which was not our intention. The balance had to be achieved. So we started from the entrance...; the first contact of humans with a cave. Then and before entering into the cave we tried to describe its morphology in a general and macroscopic way. Then we started walking on it trying to entice the reader into an exploration, as a caver would do, stopping at points of interest that help the interpretation of the whole cave-system. Special emphasis was made on the speleothemes since except from their high aesthetic value they due their existence to very special mechanisms and conditions that happen once and are never repeated (fig.11, 12). Furthermore, we presented the geology of the wider area and the speleogenesis procedure, by using and evaluating synthetically different theories and at times, ending up to our own assumptions. Geologists assisted us a lot during this stage of analysis. Then we presented information about the hydrological function of the caves, especially since their connection with the water makes them particularly interesting and important for the locals. Finally, we searched the contemporary relationships between the inhabitants and the caves. Except of all the above, we decided to provide the reader with supplementary information that would help him obtain a better image on karstology, geology etc. So in the first pages we presented the geological history of Crete, the chronological archaeological map and a map of Crete with all the caves. Methodologically, we adopted the following practices: - the use of windows, which are autonomous texts in some pages which, without interrupting the continuity of the text, manage to discharge the later, providing at the same time the reader with very important information on the decoration (for example the formation of stalactites, curtains, helictites etc.). We also gave information on diverse shapes of the rocks, or the mud which are indicators for the hydrological behavior of the cave as well as their evolution throughout the ages. - The use of maps. - The use of 3-D projections of the cave using the Visual topo (fig. 14). - The drawing of sketches that animate the speleogenesis (fig. 13). - 3-D animations of the grand-relief with the cave-topogaphy integrated into the map. For this we had the support of Greek experts, who used the OziExplorer software, satellite images of NASA and maps from the Greek army (fig.15) - the use of glossary. After almost 4 years of field-work. Writing. Editing.. you all would expect that the book would already have been published. We too expected it in the first place! However, throughout all this procedure, we realised that for such an initiative the abilities that one should have should combine speleological expertise and unfortunately, lobbying-skills The book is not yet published, however, it is about to be soon Before we close, we would like to thank profoundly for their support to all the above work: fig.7 Other karstic phenomena in Tafkos area. Cave Fantaxospiliara 441 fig.8 Diving in Manna Nerou fig.9 Opening blocked tunnels in Chonos 14th International Congress of Speleology

5 - the general secretary of Youth, in particular the Community programme YOUTH FOR EUROPE for funding the field-work, - the rescue team of the Hellenic Federation of Speleology for the effective rescue of 3 members of the club that were trapped in one fig.10 Bat-sambling in Sarchos of the caves during the topography work, - many of the individual cavers all over Greece who supported thoroughly this initiative and who bolstered our belief that changes pass through obstinacy and disinterested cooperation. fig.11 stopping at points of interest that help the interpretation of the whole cave-system 442 fig.12 Fossils in Tafkos fig.14 The use of 3-D projections of the cave using the Visual topo fig.15 3-D animations of the grand-relief with the cave-topography integrated into the map OziExplorer software, satellite images of NASA, maps from the Greek army fig.13 Using sketches for the explanation of speleogenesis