Most representative geosites of Lithuania

J.Satkunas*, V.Mikulenas*, A.Lincius** and V.Baltrunas**

*Geological Survey of Lithuania, Konarskio str. 35, 2600 Vilnius LITHUANIA
**Institute of Geology, Vilnius, Sevcenkos str. 13, 2600 Vilnius, LITHUANIA

 

ABSTRACT. The list of most representative geosites of Lithuania has been composed. The geosites could be subdivided into the three major groups: the landforms and landscape features, Quaternary type sections and pre-Quaternary type sections. The following criteria for selections have been identified: scientific value, educational meaning, historical-ethnographical meaning, aesthetic value, touristic attraction and relevance for practical use. Taking into account the peculiarities of geological structure - thick Quaternary cover, formed during glacial and interglacial stages, and bedrock formed by sedimentary rocks - the most representative geosites demonstrate typical geological and geomorphological features of Lithuania.

Peculiarities of geology and geomorphology of Lithuania - brief overview
The pre-Quaternary bedrock is presented by sedimentary rocks of Palaeozoic, Mesozoic and Tertiary age, continuously covering the pre-Cambrian crystalline bedrock, which occurs at depth of 300-400 metres in Eastern part and at depth 2000 - 2500 metres in Western Lithuania. The pre-Quaternary rocks - starting with Devonian sediments could be observed in a day light in few natural outcrops in river valleys or in artificial outcrops made due to exploitation of Devonian dolomite, Permian limestone, Triassic clay or Neogene quartz sand. Outcrops with blocks of pre-Quaternary rocks, glacially dislocated, there are known as well in several river valleys of Lithuania.

The territory of Lithuania could be regarded as one of classical regions with Quaternary cover formed during continental glaciations. The geological maps at regional scale display distribution of Quaternary deposits covering continuously whole territory of Lithuania. The thickness of this cover is in average 130 metres and varies from 10-30 m in the northern part of country - area of prevailing glacial erosion - up to 200-300 m in ice marginal highlands and the ancient buried valleys or paleoincisions. Through the Quaternary period Lithuania has been covered by continental ice sheets originated in Fennoscadinavia which corresponds to all glaciations known so far in Eastern Europe (Gaigalas 1995), thus causing very complicated structure of the Quaternary cover. Processes of accumulation and erosion during the glaciations as well as interglacial intervals have created the wide genetical variety of sediments and landforms. These processes also have made the great impact creating the present morphology of the pre-Quaternary surface.
The sediments and landforms of at least of 6 glacial stages and 8 ice free periods could be revealed and observed in stratigraphic cross-section of Quaternary of Lithuania. Due to this, the territory of Lithuania has served as a key region in solving of many stratigraphical problems of Quaternary of the whole Eastern Baltic area (Gaigalas 1995, Kondratiene et al. 1993). So, the territory of Eastern Lithuania, especially the area of border of Weichselian ice maximum extension, could be considered as stratigraphic archive, providing very important knowledge on glacial history for all continentally glaciated territory of Northern Hemisphere.

The legally protected geological monuments and geological reserves
The official list of legally protected geological monuments of Lithuania contains now 162 objects: 99 erratic boulders, 26 outcrops (mainly of Quaternary deposits), 25 hydrogeological objects and 12 geomorphological objects. Besides that, the 20 geological reserves there are established for conservation of assemblages of erratic boulders, outcrops and fossiliferous sites, particular landforms (Lincius 1994). The geological objects of Quaternary age there are dominating in the list of protected geological monuments and reserves. The protected sites comprise most of particular geological phenomena or it evidences like big erratic boulders, picturesque landforms such as kames and eskers, springs etc., having big national natural heritage value. In most cases, the protected geological objects have particular historical, cultural and ethnographical value as well.

The landscape features, including the geological phenomena, there are protected in 5 national parks, 30 regional parks, 30 geomorphological reserves, 61 landscape reserve and 35 hydrographic reserves. Besides that, the landscape elements there are protected in the numerous reserves, established for protection of animate nature. So generally, the landscape, relief together with subsurface features, there are legally well protected in Lithuania and are regarded as part of national natural heritage with it's implication for culture, science, education and tourism.

The criteria for selection of the top list of the geosites
In order to compose the top list of geosites the following criteria have been used: scientific value, educational meaning, historical-ethnographical meaning, aesthetic value, touristic attraction, relevance for practical use (Baltrunas et al, 1997). Taking into account the peculiarities of geological structure - thick Quaternary cover, formed during glacial and interglacial stages, and bedrock formed by sedimentary rocks - the most representative geosites should demonstrate typical geological and geomorphological features of Lithuania. Therefore, the scientific value and representativeness of the geosites was the main criteria defining the value of the particular object. The geosites selected could be subdivided into 3 groups: landforms and landscape features, Quaternary type sections (outcrops) and Pre-Quaternary type outcrops.

Landforms and landscape features

 

 

 

The Kursiu Nerija (Curonian Spit, Fig. 1) is the 100km long and narrow (0.4 - 4.0km), peninsula situated in the Baltic Sea. The Curonian Spit is known due to largest in Eastern Europe eolian active dunes (58.4 - 67.4 m height), the lagoon marl (clayey gyttja) outcrops, exposed below the eolian deposits and the deposits of the amber. The Curronian Spit (its Lithuanian part belongs to the National park, which has been founded in 1991. The 3 separate dunes and 1 exposure of the lacustrine marl are declared as geological monuments.

The Birzai karst area is located in the Northern Lithuania. The karst develops in fractured gypsiferous rocks of Tatula Formation of Upper Devonian Frasnian Stage. There the both the surface and underground karst forms are distributed. Surface karst forms include sinkholes, depressions and notches, underground ones - widened fractures, canals, cavities, caves, etc. Sinkholes are most widespread among surface karst forms. More than 8500 of them are found. In some places more then 200 of sinkholes are concentrated in one square kilometre. Most of sinkholes are dry, some of them are partly filled up by water and turned into small karst lakes or peat bogs. In cases, when sinkholes reach artesian water, in favourable geomorphological conditions springs arise with mineralised water. In valleys of rivers karst notches, outcrops and cavities are found. All these features make particular landscape which is protected in the Birzai Regional Park and 4 geological reserves. Selected sinkholes and karstic springs are declared as geological monuments.

 

 

 

 

The Seskine esker (Fig. 2) is situated in very Vilnius territory. It is typical 1.16 km long and 50 wide radial esker, formed in glacial conditions. This classical esker denoting maximum advance of the Weichselian glaciation is known since end of XIX century. The Seskine is declared as geological monument since 1964 and is very popular place for recreation.

 

 

 

 

 

 

The Velnio Duobe (Devils Hole, Fig. 3) is located in south - eastern Lithuania in picturesque vicinities of Aukstadvaris town. The diameter of this hole (kettle) is 200 - 220 m, depth 40 m. This form is located within the area of marginal moraines of the Late Weichselian. Its genesis is disputable, some scientists regards this hole as impact crater, due to its typical morphology. However, its thermokarstic origin is declared by other researchers. The Velnio Hole has been declared as geological monument since 1964.

The Puntukas Boulder is the large typical erratic boulder of Fennoscandinavian origin. The Puntukas is geological monument since 1964 and the monument of culture and art since 1972.

The Puokes Akmuo (The Puokes Stone, Fig. 4) is the largest erratic boulder, known so far in Lithuania). Its height is 3,6 m, length - 13.35 m, width - 7,53 m, horizontal size - 32 m. This boulder is located in North - Western part of Lithuania (Skuodas district). The Puokes Akmuo is geological monument since 1964.

Fig. 4.

Quaternary type sections (outcrops)

The Rokai outcrop (Fig. 5) is situated on the right bank of the Jiesia River (left tributary of the Nemunas River) near Kaunas. The surrounding topography is flat till plain covered by varved clays. The section is 34 metres high and from top to bottom displays 8 beds of deposits of different age and genesis. Particularly the section is interesting due presence of lacustrine deposits attributed to the Middle Weichselian stage. The upper part of the section is composed of the four Late Weichselian till units. In the lowermost part of the outcrop, close to the present-day river level, a layer of grey silty/clayey till of the Medininkai (Saalian) glaciation occurs. The outcrop is included into the Jiesios landscape reserve.

Fig. 5.

The Jonionys site is located in the valley of river Nemunas, 3 kilometres downstream from the town Merkine within the belt of marginal formations of the last (Nemunas, Weichselian) glaciation. The organic interglacial and interstadials sediments at the site form the basement of a fluvial terrace of the river Nemunas and are overlain by alluvial fine sands and gravel, together 3­5 m thick. The height of this terrace is 11­13 m above the water level of Nemunas. The Jonionys area is dissected by a deep valley of a small tributary stream ­ Didzioji Jonioniu Griova (The Big Ravine of Jonionys). The deposits exposed in outcrops at Jonionys belong to the Merkine (Eemian) Interglacial and Early Nemunas (Weichselian) stages. As the interglacial sediments comprise and represent the whole Merkine Interglacial, the Jonionys site has been established as stratotype for the Merkine (Eemian) Interglacial in Lithuania (Kondratiene et al. 1993). Most recent data displays (Satkunas and Grigiene 1997) presence of three independent interstadials (Brorup, Odderade and Oerel) above the Eemian deposits in the Jonionys section. So the section of the Jonionys palaeolake represents a continuous sedimentation and vegetation history starting with the Eemian Interglacial and ending with the middle of Middle Weichselian.. The site is included in the Dzukija National Park, besides that, the Big Jonioniu Ravine is geological monument since 1974.

The Buivydziai outcrop (35 m height, located in valley of Neris) is known due to presence of layer of gyttja attributed to the Snaigupele Interglacial (Kondratiene & Vishnevskaja 1974). This layer so far has a meaning as parastratotype of the Snaigupele Interglacial (Kondratiene et al. 1993). Besides the interglacial gyttja, the exposure presents very interesting section of Middle-and Late Pleistocene, characteristic for the area of maximum extent of Last Glaciation (Satkunas 1997). General thickness of Quaternary in the Buivydziai site is 70-80 m. Within its structure, 4 layers of tills have been recorded and attributed to Dainava, Zemaitija, Medininkai and Gruda glacial units. The outcrop is not officially protected.

The Skevonys outcrop is located in valley of river Nemunas in vicinities of Birstonas town. The outcrop is 24 m height and displays Middle Pleistocene (Medininkai) and Upper Pleistocene tills (6 separate units) separated by crust of weathering, formed during the Eemian interglacial. The site is geological monument and belongs to the Nemuno Kilpu Regional Park.

The Plikakalnis outcrop is situated at the right bank of the Neris river in Vilnius territory. The outcrop is 60 m high and the section exposed comprises following stratigraphic units: Elsterian (Dainava) glaciation, Holsteinian (Butenai) Interglacial, Early Saalian (Zemaitija) glaciation, Snaigupele Interglacial, Late Saalian (Medininkai) glaciation. The section is composed of tills, lacustrine, glaciofluvial and glaciolacustrine sediments. The outcrop is geological monument and belongs to the Karoliniskiu landscape park.

The Snaigupele outcrop is the stratotype section of the Snaigupele Interglacial is located in valley of the Snaigupele river (small tributary of Nemunas), 2.5 km NE of the Druskininkai town. The Snaigupele gyttja (1m), exposed in this section, is covered by brown till 2.5 thick. The site is well investigated, however the stratigraphic position of the Snaigupele Interglacial is problematic and this is an object of scientific discussions (Baltrunas 1996). Palynological data indicate that the deposits of the Snaigupele Interglacial are younger than the beds of the Butenai (Holsteinian) Interglacial and older than the Merkine (Eemian), however the conditions of occurrence of the interglacial layer do not support this conclusion. The outcrop is geological monument.

The Viriai outcrop is located in valley of the Neris river, northern suburb of Vilnius. The section is 30 metres high and particularly steep. It displays large glaciotectonic structure of the Middle Pleistocene age and is composed of till with few lenses of dislocated sand. The section is evidence of the Major Saalian glaciation. The outcrop has no protected status, however this site belongs to the Verkiu Regional Park.

The Butenai outcrop is located in the valley of Sventoji river, north of Utena town in north-eastern Lithuania. This outcrop is the stratotype of the Butenai (Holsteinian) Interglacial. The outcrop is only 2 -4 m high, however represents typical vegetation development, determined by pollen and spores data, during the Holsteinian Interglacial in Lithuania. The outcrop has no protected status.

The Daumantai outcrop. The Daumantai stage comprises the oldest Quaternary deposits known in Eastern Baltic region. The stratotype for the Daumantai preglacial formation was suggested the 25 m high outcrop of river Sventoji at Daumantai village (Kondratiene et al. 1993), where the Daumantai formation overlay the Anyksciai (Upper Pliocene) formation and a boundary between Quaternary (the Daumatai formation) and Neogene (Anyksciai formation) is presented. This Quaternary/Neogene boundary was established by pollen and lithological criteria. Besides, the Upper Devonian sandstone is exposed and makes the basement of the outcropping sequence. The section is unique as displaying the Neogene/Quaternary boundary in terrestrial sediments. The outcrop has no protected status, however this site belongs to the Anyksciu Regional Park.

Pre-Quaternary type outcrops
This group of geosites includes natural exposures as well as sections occurring in the artificial quarries due to mineral resources extraction.

The Varius exposure is located in village Stakiu and represents section (9metres high)of Lower and Upper Neogene. Sediments are composed of very fine quartz sand. This sand is attributed to the Anyksciai formation of Upper Pliocene. This formation has big practical significance is being excavated from the deposit near Anyksciai town. The outcrop is geological monument since 1987 and belongs also to the Anyksciu Regional Park.

The Papile outcrop is the most widely known among the number of the Jurassic exposures in the valley of Venta. The section is 10.4 m high and is composed of black clay with mica and siderite concretions, limestone, brown sandstone, clay and sand of Late Jurrasic (Callovian Stage). This sequence is covered by Quaternary till, 15 m thick. Characteristic fossils (Grigelis 1994): Oxytoma inaequivalvis, (Sow.), Chlamys (Aequipecten) fibrosa (Sow.), Protocardia cognata (Phill.), Trigonia (Trigonia), zonata Ag., Myophorella undulata (Ag.), Astarta sauvagei Lor. and Astarte trembrazensis Lor., Kosmoceras jason Rein., Kosmoceras castor Rein., Kosmoceras obductum Buck., Kosmoceras transitionis Nik., Kosmoceras cf. compressum Quenst. The exposure is known for scientists since 1825, and collections of fossils from the Papile is available in many European Universities since last century. Biggest collections of fossils is at Vilnius University and Institute of Geology in Vilnius. Geological monument since 1964, also this site belongs to the Ventos Regional Park.

The Karpenai outcrop (Fig. 6) is located in deep and big quarry of the limestone of formation of Naujoji Akmene (Upper Permian). The Section exposed in the quarry is 20 metres high and represents typical section composed of three layers: lower clayey limestone, middle - limestone, upper - dolomite with high content of limestone. Palaeokarstic phenomena could be observed in the section. The site has no protected status.

Fig. 6.

 

 

 

 

 

 

The Saltiskiai outcrop (Fig. 7) is located in the quarry of clay of Lower Triassic. The sections there displays upper part of the marine clay layer, which is up to 96 m thick. The clay is differently coloured, contains lenses of silt, quartz sand or even gravel. The clay has practical meaning and is used for cement production. The sections are not officially protected because occur in the quarry, where clay extraction is still ongoing.

Fig. 7.

The Armona outcrops are located in the Armona river valley, Ukmerge district. The Upper Devonian Sventoji member deposits occur under the thin cover of Quaternary. The visible sections 2.5 6.2 m high display sand, sandstone and siltstone. The outcrops are well known and valuable due to fossils of ichtiofauna: Asterolepis radiata Rohon, Psammolepis undulata Ag., Laccognathus panderi Gross, Glyptolepis baltica Gross, Panderichthys rhombolepis (Gross), Dipteris sp. Five outcrops make the Armona geological reserve

Discussion and concluding remarks
The selection of the most representative national geosites is an activity initiated by the ProGEO - European Association for Conservation of Geological Heritage. This made an impetus for reconsideration and revision of the protected sites, comparing them with the list of most scientifically significant geosites. In order to compose the top list of geosites, the scientific representativeness of the geosites was the main criteria defining the value of the particular object. The analysis, performed from this point of view shows that in spite of comprehensive list of legally protected sites and areas in Lithuania, some of most significant sites are not listed among protected geological monuments and reserves. The stratotypes, as sites of special scientific importance, in most cases have great international scientific meaning, which could be evaluated much more higher than value of particular erratic boulder or esker, having only local value. The stratotypes must be well documented, mapped and catalogued. The information about scientific value of certain outcrop should be available and accessible not only for scientific community, but it also should be provided for local people and authorities, expecting public awareness. The information on most valuable geosites is also very important for elaboration of plans of environmental protection, territorial planning, geotourism and education. The primary list of most representative geosites of Lithuania has been compiled in 1997. The article "List of the most representative geosites of Lithuania" was published in Polish Geological Institute Special Papers, 2: 97-102 (1999).

Fig. 8. The Sviles Saltiniai (water springs)

In 1998 this list was enlarged by six geosites: Velniapilis (outcrop with niche), Muoriskiai (outcrop), Skaliu Kalnas (outcrop), Zalsvasis Saltinis (karstic water spring), Kavarsko Saltinis (water spring) and Sviles Saltiniai (water springs, Fig. 8). Enlarged list was published in Geologijos Akiraciai, 1 (33) / 1999 (in Lithuanian). Review of these geosites and others geotopes of Lithuania is possible on the Internet: www.lgt.lt

References:
Baltrunas, V., 1995: Stratigraphy and correlation of Pleistocene. Methodical questions. - Vilnius: Academia. 178p.

Baltrunas V., Lincius A. & Satkunas J., 1997: The top list of the geosites of Lithuania. - in ProGEO'97: The Second General Assembly of the European Association for the Conservation of the Geological Heritage: Scientific Conference, Tallin-Lahemaa National Park, Estonia, June 2nd-4th, 1997 : Brochure of Abstracts. - Tallin, 1997.

Gaigalas, A. 1995: Glacial history of Lithuania In Glacial deposits in North-East Europe.-Rotterdam,1995. P.127-135.

Grigelis, A. 1994: Kreida. In Lietuvos Geologija. Vilnius 1994. P.139-138

Kondratiene, O. & Vichnevskaya, E., 1974: New data on interglacial deposits in Buivydziai. Voprosy izuchenija chetvertichnyh otlozenij Litvy. LitNIGRI, vol.27, Vilnius, 100-118. (In Russian).

KONDRATIENE, O. et al, 1993: Catalogue of Quaternary stratotypes of the Baltic region. Vilnius.

LINCIUS, A. 1994: Lietuvos geologijos paminklai ir draustiniai. Zemelapis M 1:500 000. [Geological monuments and reserves of Lithuania. Map sc.1:500 000]. Lietuvos geologijos tarnyba.

SATKUNAS, J. AND GRIGIENE, A. 1997: The Jonionys site - sequence of the Eemian Interglacial and the Weichselian interstadials. The Late Pleistocene in Eastern Europe: stratigraphy, palaeoenvironment and climate.- Abstract volume and excursion guide of the INQUA - SEQS Symposium in Lithuania, September 14-19, 1997. P.77-81.

SATKUNAS, J., MIKULENAS, V., LINCIUS, A. & BALTRUNAS, V, 1999: List of the most representative geosites of Lithuania. In Polish Geological Institute Special Paper. - 1999. - No. 2. - P. 97-102.

SATKUNAS, J. 1997: The Buivydziai outcrop: Upper Pleistocene sequence and conditions of occurrence of the Snaigupele Interglacial gyttja. //The Late Pleistocene in Eastern Europe: stratigraphy, palaeoenvironment and climate. - Abstract volume and excursion guide of the INQUA - SEQS Symposium in Lithuania, September 14-19, 1997. P.96-100.

Vertingiausi Lietuvos geologiniai krastovaizdzio objektai [The most valuable landscape geological objects of Lithuania] / compiled by V.Baltrunas, A.Lincius, V.Mikulenas, V.Narbutas, J.Satkunas In Geologijos akiraciai. - 1999. - Nr.1. - P. 72-73.