Ice caps once covered large areas of Mount Orjen (1894 m), on the Adriatic coast of Montenegro/Bosnia Herzegovina/Croatia. The largest ice cap covered an area of c. 165 km
2 and reached a maximum ice ...thickness of c. 450 m, in some areas reaching down to 500 m above modern sea level. U-series dating of secondary carbonates within moraines indicates that the most extensive glaciation occurred during the Middle Pleistocene, correlating with a major phase of glaciation in Greece to the south during MIS 12 (c. 480–430 ka). Later, less extensive, glaciations are also recorded in the cirques and valleys and correlate with glaciations during MIS 6 (190–130 ka) and MIS 5d-2 (110–11.7 ka). Each phase of glaciation would have required large amounts of snow accumulation. Under modern precipitation values, which at c. 5000 mm are some of the highest in Europe, mean annual temperatures would need to be only c. 5–6 °C lower in order to form similar sized glaciers today. A mean annual temperature depression of 12–13 °C would still require >1000 mm of snow accumulation (water equivalent) to balance ablation, suggesting sustained moisture supply during Pleistocene cold stages. Such sustained precipitation supply during Pleistocene cold stages is likely to have been facilitated by major temperature contrasts between the European landmass and the Mediterranean Sea, which are likely to have sustained lee-side vortices to the south of the Alps, in the Gulf of Genoa and Adriatic Sea, forming weak moisture-bearing depressions which tracked across the eastern Adriatic coastal mountains. Large ice caps on the Dinaric Alps would have blocked the inland penetration of these depressions, resulting in much drier conditions in the Balkan interior, creating favourable conditions for the deposition of thick accumulations of loess. The last glaciers on Orjen formed during the Younger Dryas (12.9–11.7 ka) and confirm the influence of North Atlantic Ocean circulation on Pleistocene climate change in this part of the Mediterranean.
Large-scale coupling between headwater catchments and downstream depocentres is a critical influence on long-term fluvial system behaviour and on the creation of the fluvial sedimentary record. ...However, it is often difficult to examine this control over multiple Quaternary glacial cycles and it has not been fully explored in karst basins. By investigating the Pleistocene glacial and fluvial records on and around Mount Orjen (1894 m) in Montenegro, we show how the changing connectivity between glaciated mountain headwater source zones and downstream alluvial basins is a key feature of long-term karst system behaviour – especially in relation to the creation and preservation of the surface sedimentary record. Middle and Late Pleistocene glacial deposits are well preserved on Mount Orjen. Uranium-series dating of 27 carbonate cements in fluvial sediments shows that many alluvial depocentres were completely filled with coarse glacial outwash before 350ka during the largest recorded glaciation. This major glaciation is correlated with the Skamnellian Stage in Greece and Marine Isotope Stage 12 (MIS 12, c 480–420ka). This was a period of profound landscape change in many glaciated catchments on the Balkan Peninsula. Later glaciations were much less extensive and sediment supply to fluvial systems was much diminished. The extreme base level falls of the Late Miocene produced the world's deepest karst networks around the Mediterranean. After MIS 12, the subterranean karst of Mount Orjen formed the dominant pathway for meltwater and sediment transfer so that the depositional basins below 1000 m became disconnected (uncoupled) from the glaciated headwaters. There is little evidence of post-MIS 12 aggradation or incision in these basins. This absence of later Pleistocene and Holocene fluvial activity means these basins contain some of the thickest and best-preserved outwash deposits in the Mediterranean.
•We assess glacial–fluvial system coupling over multiple glacial cycles.•We analyse 12 alluvial records using 48 sedimentary exposures and 27 U-series ages.•MIS 12 was a period of profound landscape change and enhanced sediment supply.•Deep karst exerted a major control on Pleistocene glacial–fluvial processes.•Karst drainage is a major control on the preservation of the alluvial record.
We studied the site ecology of
(Lamiaceae), a narrow endemic of the eastern Adriatic, which is now restricted to only three sites, using the sigmatistic method and numerical analyses. Four ...floristically and ecologically well-defined groups of stands, representing different syntaxa, were identified, corresponding to the sampling sites. The majority of stands represent dry eastern (sub)Mediterranean rocky grasslands at different successional stages towards (sub)Mediterranean forest vegetation. Compared to the evolutionary and ecologically closely related and sympatric
, the morphologically easily distinguishable
differs in its flowering phenology and prefers relatively cooler, wetter, deeper and nutrient richer soils, which are developed on dolomite or dolomitic limestone at higher elevated sites. Despite its ability to cope with interspecific competition by means of clonal reproduction better than its congener, the populations are severely threatened by abandonment of traditional land use and by fires, making the species endangered (EN) according to IUCN criteria.
As the region of Eastern Herzegovina and the Boka Kotorska (Kotor Bay) area is one of the most highly karstified areas in the world, its hydrogeological properties, typical for karst, are extremely ...exposed. The main erosion base-levels for surface and underground waters of that region are: the Neretva River valley in the west, the Adriatic Sea and Dubrovnik littoral in the south and Boka Kotorska in the east. At the same time it belongs to one of the most investigated karst regions in the world known as the Dinaric Karst. The basic theories related to the nature of karst are based on the multidisciplinary and long-lasting investigation of this particular region. World famous karstologists such as Cvijić, Grund, Katzer and many others created crucial theories of karstology based on investigations and analysis of the Dinaric Karst. Many large and successfully constructed structures (dams, reservoirs and tunnels) of the region also became the basis for the development of engineering karstology. Massive karst investigation works were also performed during the twentieth century. The accumulated data and knowledge have been presented at many scientific conferences and has also appeared in many publications. The text below presents in brief, the general natural properties of the region and represents only a small part of the available data.
A single species of Roncus L. Koch, 1873, which was collected in the Baretina
Lokva on Mt. Orjen, Montenegro, is new to science (R. teutae n. sp.) and
described herein. Its diagnostic characters are ...illustrated and their
distribution is provided. The possible establishment of this species of
Roncus is presented briefly in view of the importance and analysis of its
diagnostic characters.
This paper explores the modification of limestone bedrock and fine-grained sediment within the Pleistocene glacial and proglacial environments of the rjen massif in western Montenegro. We have ...characterised the fine-grained components of till and outwash using lithological and particle size data. Two main types of fine-grained outwash sediment have been recognised and each is associated with a distinctive meltwater route. Fine-grained sediments deposited downstream of bedrock gorges (type 1 meltwater route) typically display a bimodal particle size distribution, where the carbonate silt fraction (10-60 μm) has been depleted and non-carbonate silts become dominant. This probably reflects both physical sorting and corrosion of the fine-grained limestone sediment within the proglacial fluvial environment. The 10-60 μm component matches the particle size characteristics of typical loess. Fine-grained outwash deposits from directly in front of the former ice margin (type 2 meltwater route) show unimodal particle size distributions which more closely resemble the grain size characteristics of the glacial till, but they also show evidence of silt depletion. We argue that the fine-grained sediment exported from glaciated limestone catchments during the cold stages of the Pleistocene formed an important source of the carbonate-rich loess in this region.
Orjen Riđanović, Josip
Acta Geographica Croatica,
10/1966, Letnik:
5., Številka:
1.
Paper
Odprti dostop
Rad obrađuje tematiku Orjena, njegov nastanak, geološku građu i morfologiju. Poseban osvrt u radu dan je glacijalnom utjecaju na krški reljef Orjena, snježnoj međi, ali i posebnosti glacijacije na ...Orjenu.
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