Dimiter Ivanov

Palynological evidence for Miocene climate change in the Forecarpathian Basin (Central Paratethys, NW Bulgaria)

Abstract We reconstruct quantitatively the Middle to Upper Miocene climate evolution in the southern Forecarpathian Basin (Central Paratethys area, Northwest Bulgaria) by applying the coexistence approach to 101 well-dated palynofloras isolated from three cores. The climatic evolution is compared with changes in vegetation and palaeogeography. The Middle Miocene was a period of a subtropical/warm–temperate humid climate with mean annual temperature (MAT) between 16 and 18°C and mean annual precipitation (MAP) between 1100 and 1300 mm. Thereby, during the entire Middle Miocene a trend of slightly decreasing temperatures is observed and only small climate fluctuations occur which are presumably related to palaeogeographic reorganisations. The vegetation shows a corresponding trend with a decrease in abundance of palaeotropic and thermophilous elements. The Upper Miocene is characterised by more diverse climatic conditions, probably depending on palaeogeographic and global climatic transformations. The beginning of this period is marked by a slight cooling and a significant drying of the climate, with MAT 13.3–17°C and MAP 652–759 mm. After that, fluctuations of all palaeoclimate parameters occur displaying cycles of humid/dryer and warmer/cooler conditions, which are again well reflected in the vegetation. Our study provides a first quantitative model of the Middle–Upper Miocene palaeoclimate evolution in Southeastern Europe and is characterised by a relatively high precision and resolution with respect to the climate data and stratigraphy.

19. Mire Kupena, Western Rhodopes Mountains (South Bulgaria)

Site details Mire Kupena is a former lake (41◦ 59′ 07.5′′ N, 24◦ 19′ 05.1′′ E; 1356 m above sea level (a.s.l.)) located on the territory of the Biosphere Reserve Kupena, Western Rhodopes Mountains, Bulgaria. The reserve is located between 600 and 1400 m a.s.l. on a north-facing slope and its vegetation is rather diverse. In the lower parts, the most common plant communities are those of Quercus dalechampii Ten. mixed in some places with Carpinus betulus L., Fagus sylvatica L., Pinus nigra Arn. and Pinus sylvestris L. At higher altitudes, plant communities of F. sylvatica dominate, followed by those of Pinus sylvestris with some Abies alba Mill. and Picea abies (L.) Karst. The mire is formed in a depression on an area of 6 ha, surrounded by an almost pure forest of Pinus sylvestris with an admixture of Picea abies, A. alba, F. sylvatica, Betula pendula Roth., Sorbus aucuparia L., Q. dalechampii and an undergrowth of Juniperus communis L., Vaccinium myrtillus L. and V. vitis-idaea L. The mire vegetation is represented by sparse moss cover (Sphagnum spp.) and includes various species of Carex, Juncus, Potentilla, Ranunculus, Galium. The basin is fed by rainfall and water from melting snow. During the last two decades most of the mire surface on the hummocks has been overgrown by pine trees (Huttunen et al., 1992; Bozilova et al., 2011). The climate in the area is montane with a mean annual temperature of 5–10 ◦S and a mean annual precipitation of 600–800 mm with a maximum in May–June. The basic soil types are brown forest (60%), humic-carbonate and cinnamomic-forest.

Miocene microflora and palaeoclimate reconstructions from three sites in Bulgaria

In this study we reconstruct quantitatively the Middle to Upper Miocene climate evolution in the southern Forecarpathian Basin (Central Paratethys area, Northwest Bulgaria) by applying the coexistence approach to 101 well-dated palynofloras isolated from three cores. The climatic evolution is compared with changes in vegetation and palaeogeography. The Middle Miocene was a period of a subtropical/warm–temperate humid climate with mean annual temperature (MAT) between 16 and 18°C and mean annual precipitation (MAP) between 1100 and 1300 mm. Thereby, during the entire Middle Miocene a trend of slightly decreasing temperatures is observed and only small climate fluctuations occur which are presumably related to palaeogeographic reorganisations. The vegetation shows a corresponding trend with a decrease in abundance of palaeotropic and thermophilous elements. The Upper Miocene is characterised by more diverse climatic conditions, probably depending on palaeogeographic and global climatic transformations. The beginning of this period is marked by a slight cooling and a significant drying of the climate, with MAT 13.3–17°C and MAP 652–759 mm. After that, fluctuations of all palaeoclimate parameters occur displaying cycles of humid/dryer and warmer/cooler conditions, which are again well reflected in the vegetation. Our study provides a first quantitative model of the Middle–Upper Miocene palaeoclimate evolution in Southeastern Europe and is characterised by a relatively high precision and resolution with respect to the climate data and stratigraphy.

LATE MIOCENE FLORA FROM KARLOVO BASIN (SOUTHERN BULGARIA). NEW FLORISTIC AND PALAEOECOLOGICAL DATA

This paper presents the results from taxonomical and palaeoecological analysis of the Late Miocene flora from Karlovo basin. The studied flora comes from borehole C-556 located in the eastern part of the basin. The percentage contribution of individual taxa allowed us to dierentiate the main vegetation types in the area. The pollen data indicate widest distribution of mixed mesophytic forest communities (Quercus, Fagus, Ulmus, Carya, Pterocarya, Carpinus, Betula), existence of hygrophytic (swamp) forests and distribution of the herbaceous palaeocoenoses (high values of Poaceae, Chenopodiaceae, Apiacea, Asteraceae, Artemisia, Thalictrum, Polygonum, Caryophyllaceae, Cichorioideae, Lamiaceae). According to the pollen data, the palaeoflora from Karlovo basin reflects warm-temperate climate during the studied period.

17. Lake Skakavitsa (Bulgaria): Late Holocene vegetation dynamics in north-western Rila Mountains

The lake Skakavitsa (Skakavishko ezero) is located in the lower part of the subalpine vegetation belt of the north-western part of the Rila Mountains [42◦ 12′ 52′′ N, 23◦ 18′ 18′′ E, 2170 m above sea level (a.s.l.)]. It has an elongated shape narrowing in its northern part and is about 250 m long and 60 m wide. The western shores are rocky and abrupt, the other are flattened. The inflow lies to the south and the outflow to the north, which forms the beginning of the river Skakavitsa (Stoyneva & Michev, 2007). The lake lies in a shallow cirque and is of glacial origin. The core was taken from a marginal peat land in the shallow south-eastern part of the basin. The major peat land plants are Sphagnum capillifolium (Ehrh.) Hedw. and Polytrichum commune Hedw. The lake is surrounded by dense Juniperus sibirica Burgsd., Pinus mugo Turra and Vaccinium uliginosum L. scrubs with herbaceous communities on open areas. The most common taxa in the herbaceous vegetation are Bistorta vivipara (L.) Delarbre, Empetrum nigrum L., Bruckenthalia spiculifolia Rchb., Homogyne alpine Cass., Carex rostrata Michx., Alopecurus gerardii Vill., Avenula versicolor (Vill.) M. Laínz, Potentilla erecta Raeusch., Eriophorum, Pseudorchis albida (L.) Á. Löve & D. Löve, Euphrasia, Agrostis, Carex, Nardus stricta L., Plantago media L., Festuca, Luzula, Deschampsia, Juncus, Geum coccineum Sibth. & Sm., Allium, Gentianella bulgarica (Velen.) Holub, Primula farinosa L. and Antennaria dioica Gaertn. Below the subalpine belt, a coniferous belt is developed. It is composed mainly of Pinus sylvestris L.,