Miocene flora and paleoclimate estimations of Schrotzburg, South Germany

We present a detailed palaeoclimate analysis of the Middle Miocene (uppermost Badenian-lowermost Sarmatian) Schrotzburg locality in S Germany, based on the fossil macro- and micro-flora, using four different methods for the estimation of palaeoclimate parameters: the coexistence approach (CA), leaf margin analysis (LMA), the Climate-Leaf Analysis Multivariate Program (CLAMP), as well as a recently developed multivariate leaf physiognomic approach based on an European calibration dataset (ELPA). Considering results of all methods used, the following palaeoclimate estimates seem to be most likely: mean annual temperature ~15-16°C (MAT), coldest month mean temperature ~7°C (CMMT), warmest month mean temperature between 25 and 26°C, and mean annual precipiation ~1,300 mm, although CMMT values may have been colder as indicated by the disappearance of the crocodile Diplocynodon and the temperature thresholds derived from modern alligators. For most palaeoclimatic parameters, estimates derived by CLAMP significantly differ from those derived by most other methods. With respect to the consistency of the results obtained by CA, LMA and ELPA, it is suggested that for the Schrotzburg locality CLAMP is probably less reliable than most other methods. A possible explanation may be attributed to the correlation between leaf physiognomy and climate as represented by the CLAMP calibration data set which is largely based on extant floras from N America and E Asia and which may be not suitable for application to the European Neogene. All physiognomic methods used here were affected by taphonomic biasses. Especially the number of taxa had a great influence on the reliability of the palaeoclimate estimates. Both multivariate leaf physiognomic approaches are less influenced by such biasses than the univariate LMA. In combination with previously published results from the European and Asian Neogene, our data suggest that during the Neogene in Eurasia CLAMP may produce temperature estimates, which are systematically too cold as compared to other evidence. This pattern, however, has to be further investigated using additional palaeofloras.

Palynological investigations of profile Cergowa in Poland

The decomposition rate of organic, Compounds, following the death of a plant, is dependent on several external factors. Assimilatory pigments generally undergo a rapid degradation. In certain condition, however, their decomposition may be considerably retarded; e.g. compounds similar to chlorophyll and some carotenoids, as a and ß-carotene, lutein and others, may persist several thousand years in marine and lake Sediments (Vallentyne 1960). Derivatives of chlorophyll were also found in the surface layer of wood soil (Gorham 1959). In this connection the question arises, in what a way a still different environment, namely peat, influences the decomposition rate of pigments. The starting point in these investigations was the fact observed by one of the co-authors, that many subfossil fir needles from various depths of the peat bog in Cergowa Gora were bright yellow green pigmented. Macroscopic otoservations have already suggested that, at least, a part of the pigments did not undergo decomposition. A study was undertaken with the aim to determine the quantitative and qualitative changes in assimilatory pigments, occurring in fir needles in dependence on the pexiod of time they were lying in the peat bog.

Pollen and macroremains from three sediment cores from Göttingen, Germany

In a borehole in the southern outskirts of the town of Göttingen, limnic sediments of several Pleistocene warm periods occur intercalated with coarse solifluction debris and gravel of the river Leine. Pollen analysis of the limnic sediments in a borehole at Ottostrasse gave evidence of three warm periods of interglacial character, followed by three interstadial phases. The warm phases are separated one from another by stadial phases with, at least in one case, indications of periglacial solifluction. This sequence belongs to the Brunhes magnetic epoch. The pollen data allow to exclude an Eemian or Holsteinian age of the warm period sediments. Thus a Cromerian age is assumed, though the exact position of the newly described warm periods within the ''Cromerian'' remains uncertain. A section in a borehole at Akazienweg is of Holsteinian age.

Pollen and macroremains from profiles from site Osterholz and Elm

The biostratigraphic classification of the Pleistocene in north-western and central Europe is still insufficiently known, in spite of numerous geological and vegetation-history investigations. The question is not even clear, for example, how often a warm-period vegetation with thermophilous trees such as Quercus, Ulmus, Tilia, Carpinus etc could develop here. In past years, on the basis of several geological and vegetation-history findings, suspicion has often been expressed that some of the classical stages of the Pleistocene could include more warm periods than heretofore assumed, and as a result of recent investigations the period between the Waal and Holstein interglacials seems to include at least two warm periods, of which the Cromer is one. This paper contributes to this problem. The interglacial sediments coming from the Elm-Mountains near Brunswick and from the Osterholz near Elze - both within the limits of the German Mittelgebirge - were investigated by pollen analysis. In both cases a Pinus-Betula zone and a QM zone were found. The vegetation development of the Pinus-Betula zone is characterized in both sequences by the early appearance of Picea. Because of strong local influence at the Osterholz a detailed correlation is difficult. However, vegetation development at the time of the QM zone at both sites was similar; it is especially characterized by the facts that Ulmus clearly migrated to the site earlier than Quercus and was very abundant throughout this time. Furthermore, both diagrams show very low amounts of Corylus. The interglacial of the Osterholz shows in addition to the above; a Carpinus-QM-Picea-zone in which Eucommia reaches a relative high value and in the upper of which Azolla filiculoides was also found. The similarity of vegetation development justifies acceptance of the same age for the occurrences. A comparison of the vegetation development at the Elm and the Osterholz with those of the Eem, Holstein, Waal, and Tegelen warm periods as well as with all the Cromer sites so far investigated shows that only a correlation with the Cromer Complex is possible. This correlation is supported by the geologic relations in the Osterholz (the deposit is overlain by Elster till). Therefore the till-like material with Scandinavian rock fragments underlying the deposit at Elm is of particular interest. The 'Rhume' interglacial beds at Bilshausen, only 60 km south of Osterholz, is also assigned to the Cromer complex, but the two deposits cannot be of the same age because the vegetation development differs. Therefore the Cromer complex must include at least two warm periods. Further conclusions about the relative stratigraphic position of these two occurrences and correlations of other Cromer sites are at this time not possible, however.

Pollen and diatom analysis on varved sediments in Lake Jues (Harz Mountains, Germany)

Studies combining sedimentological and biological evidence to reconstruct Holocene climate beyond the major changes, and especially seasonality, are rare in Europe, and are nearly completely absent in Germany. The present study tries to reconstruct changes of seasonality from evidence of annual algal successions within the framework of well-established pollen zonation and 14C-AMS dates from terrestrial plants. Laminated Holocene sediments in Lake Jues (10°20.70' E, 51°39.30' N, 241 m a.s.l.), located at the SW margin of the Harz Mountains, central Germany, were studied for sediment characteristics, pollen, diatoms and coccal green algae. An age model is based on 21 calibrated AMS radiocarbon dates from terrestrial plants. The sedimentary record covers the entire Holocene period. Trophic status and circulation/stagnation patterns of the lake were inferred from algal assemblages, the subannual structure of varves and the physico-chemical properties of the sediment. During the Holocene, mixing conditions alternated between di-, oligo- and meromictic depending on length and variability of spring and fall periods, and the stability of winter and summer weather. The trophic state was controlled by nutrient input, circulation patterns and the temperature-dependent rates of organic production and mineralization. Climate shifts, mainly in phase with those recorded from other European regions, are inferred from changing limnological conditions and terrestrial vegetation. Significant changes occurred at 11,600 cal. yr. BP (Preboreal warming), between 10,600 and 10,100 cal. yr. BP (Boreal cooling), and between 8,400 and 4,550 cal. yr. BP (warm and dry interval of the Atlantic). Since 4,550 cal. yr. BP the climate became gradually cooler, wetter and more oceanic. This trend was interrupted by warmer and dryer phases between 3,440 and 2,850 cal. yr. BP and, likely, between 2,500 and 2,250 cal. yr. BP.

Pollen record and calculated holocene vegetation and climate dynamics from Sihailongwan Maar Lake, NE China

High-resolution palynological analysis on annually laminated sediments of Sihailongwan Maar Lake (SHL) provides new insights into the Holocene vegetation and climate dynamics of NE China. The robust chronology of the presented record is based on varve counting and AMS radiocarbon dates from terrestrial plant macro-remains. In addition to the qualitative interpretation of the pollen data, we provide quantitative reconstructions of vegetation and climate based on the method of biomization and weighted averaging partial least squares regression (WA-PLS) technique, respectively. Power spectra were computed to investigate the frequency domain distribution of proxy signals and potential natural periodicities. Pollen assemblages, pollen-derived biome scores and climate variables as well as the cyclicity pattern indicate that NE China experienced significant changes in temperature and moisture conditions during the Holocene. Within the earliest phase of the Holocene, a large-scale reorganization of vegetation occurred, reflecting the reconstructed shift towards higher temperatures and precipitation values and the initial Holocene strengthening and northward expansion of the East Asian summer monsoon (EASM). Afterwards, summer temperatures remain at a high level, whereas the reconstructed precipitation shows an increasing trend until approximately 4000 cal. yr BP. Since 3500 cal. yr BP, temperature and precipitation values decline, indicating moderate cooling and weakening of the EASM. A distinct periodicity of 550-600 years and evidence of a Mid-Holocene transition from a temperature-triggered to a predominantly moisture-triggered climate regime are derived from the power spectra analysis. The results obtained from SHL are largely consistent with other palaeoenvironmental records from NE China, substantiating the regional nature of the reconstructed vegetation and climate patterns. However, the reconstructed climate changes contrast with the moisture evolution recorded in S China and the mid-latitude (semi-)arid regions of N China. Whereas a clear insolation-related trend of monsoon intensity over the Holocene is lacking from the SHL record, variations in the coupled atmosphere-Pacific Ocean system can largely explain the reconstructed changes in NE China.

Pollen profile and age determination of sediment core Schwanengrabenrinne, Brandenburg, Germany

In der Döberitzer Heide nördlich von Potsdam wurden vegetationsgeschichtliche Untersuchungen durchgeführt. Das Untersuchungsgebiet befindet sich im östlichen Teil der Nauener Platte, die bisher vegetationsgeschichtlich weitgehend unerforscht war. In sechs verschiedenen Mooren wurden acht Bohrungen niedergebracht. Die Bohrkerne wurden stratigraphisch und pollenanalytisch untersucht und für die Radiocarbondatierung beprobt. Die Pollendiagramme ermöglichen die Rekonstruktion der Vegetationsentwicklung der terrestrischen Standorte und der Moore in der Döberitzer Heide in den letzten 14.000 Jahren. Neben einer Revision der Gliederungsprinzipien der spätglazialen Vegetationsentwicklung Brandenburgs und einer vergleichenden Betrachtung der Moorentwicklung in der Döberitzer Heide wurde besonderes Augenmerk auf die Geschichte des Döberitzer Lindenwaldes gerichtet, der einen Sonderfall in der brandenburgischen Vegetation darstellt. Die Untersuchungen boten die Möglichkeit, die Ursachen seiner Entstehung zu klären, Aussagen zu den Perspektiven seiner Entwicklung zu treffen und mögliche Entwicklungspotentiale von Lindenwäldern im Land Brandenburg aufzuzeigen.

Late Miocene palaeoflora and palaeoclimate of Lincang (China)

The Miocene Lincang leaf assemblage is used in this paper as proxy data to reconstruct the palaeoclimate of southwestern Yunnan (SW China) and the evolution of monsoon intensity. Three quantitative methods were chosen for this reconstruction, i.e. Leaf Margin Analysis (LMA), Climate Leaf Analysis Multivariate Program (CLAMP), and the Coexistence Approach (CA). These methods, however, yield inconsistent results, particularly for the precipitation, as also shown in European and other East Asian Cenozoic floras. The wide range of the reconstructed climatic parameters includes the Mean Annual Temperature (MAT) of 18.5-24.7 °C and the Mean Annual Precipitation (MAP) of 1213-3711 mm. Compared with the modern Lincang climate (MAT, 17.3 °C; MAP, 1178.7 mm), the Miocene climate is slightly warmer, wetter and has a higher temperature seasonality. A detailed comparison on the palaeoclimatic variables with the coeval Late Miocene Xiaolongtan flora from the eastern part of Yunnan allows us to investigate the development and interactions of both South Asian and East Asian monsoons during the Late Miocene in southwest China, now under strong influence of these monsoon systems. Our results suggest that the monsoon climate has already been established in southwest Yunnan during the Late Miocene. Furthermore, our results support that both Southeast Asian and East Asian monsoons co-occurred in Yunnan during the Late Miocene.

Pollen profiles from three former lakes in the Lake Garda area

1. Late glacial and postglacial sediments from three former lakes in the Lake Garda area (Southern Alps) were investigated. 2. The pollen diagram from Bondone (1550 m) shows an older phase rich in NAP. A younger one corresponds with the Younger Dryas time according to two radiocarbon determinations. In the Preboreal no climatic deterioration could be found. 3. At first plants, which are nowadays typical for snow-ground, pioneer and dwarf shrub associations, immigrated into the surroundings of Bondone. In Alleröd times larch and pine appeared as the first trees. At the beginning of the Preboreal dense forest existed in that region. During the Alleröd timber line was at about 1500 m. 4. In the pollen diagrams from Saltarino (194 m) and Fiavè (654 m) an oldest period rich in NAP is followed by two stadial and two interstadial phases. Tree birches and larches immigrated during the oldest interstadial phase. 5. In the case of Saltarino and Fiavè only a preliminary dating could be made. A correlation seems to be possible with diagrams published by Zoller as well as with the diagram of Bondone. Discrepances in dating, which arise then, are discussed. According to the two possibilities of dating the youngest stadial is synchronous either with the so-called Piottino stadial or the Younger Dryas time. Consequently the oldest interstadial phase of Saltarino corresponds either with the Bölling or with a pre-Bölling interstadial. The last possibility seems to be more probable. 6. In the southern part of the Lake Garda area reforestation was preceded by a long shrub phase mainly with Juniperus. At about 650 m there was a period with Pinus mugo and only with a small amount of Juniperus before reforestation. A phase with Betula nana well known from areas north of the Alps could nowhere be found. 7. In the area under study larch appeared as the first tree. Lateron it has been the most important constituent of the forests near timber line. Birch, which plays an important role as a pioneer tree in Denmark - for instance at the transition of the pollen zones III/IV - as well as in Southern Germany during Bölling time, was of less importance at the southern border of the Alps. In that area the spreading of Pinus occurred very early causing dense forests. 8. During the last stadial phase (probably Younger Dryas time) dense forests with Pinus and Larix existed at 650 m. In the lower part of the Lake Garda area, however, both thermophilous trees as Quercus and herbs frequently occurred. This leads to the conclusion that during this time tree growth was limited by dryness in lower altitudes of the border of the Southern Alps. Pinus and Juniperus, however, do not show higher values in this period, a fact which cannot yet be explained. 9. A list of plants, which were found in the sediments, is compiled. Helodium lanatum, Dictamnus albus, Mercurialis cf. ovata, Buxus, Cerinthe cf. minor, Onosma, Anthericum and Asphodelus albus are findings, which are of special interest for the history of the flora of that region.

Pollen record and age determination of a sediment core from the Kara Sea

AMS-14C dated sediment cores from the Ob and Yenisei estuaries and the adjacent inner Kara Sea were investigated to determine the siliclastic and organic carbon fluxes and their relationship to paleoenvironmental changes. The variability of sediment fluxes during Holocene times is related to the post-glacial sea-level rise and changes in river discharge and coastal erosion input. Whereas during the late/middle Holocene most of the terrigenous sediments were deposited in the estuaries and the areas directly off the estuaries, huge amounts of sediments accumulated on the Kara Sea shelf farther north during the early Holocene before about 9 Cal. kyrs. BP. The maximum accumulation at that time is related to the lowered sea level, increased coastal erosion, and increased river discharge due to the final stage of mountain deglaciation of the Putoran Massif. Increased supply of Yenisei-derived material indicated by peak magnetic susceptibility values probably occurred in climate-related pulses culminating near 11, 10, and 9 Cal. kyrs. BP. As sea level rose, the main Holocene depocenter migrated southward. Based on hydrogen index values and n-alkanes, the organic matter is predominantly of terrigenous origin. Maximum accumulation rates of 1.5 to more than 6 g/cm2/y occurred in the early Holocene sediments, suggesting more humid climatic conditions with an increased vegetation cover in the source area at that time. In general, high organic carbon accumulation rates characterize the estuaries and the inner Kara Sea as important sink for terrigenous organic carbon. A high-resolution record of Holocene variability of magnetic susceptibility (MS) in an AMS14C-dated sediment core from the northern Yenisei estuary may indicate natural variability of Arctic climate change and river discharge on a centennial to millenial time scale. Short-term maxima in MS probably related to warmer climate, enhanced precipitation, intensified weathering/erosion and increased river discharge, display a frequency of about 300 to 700 years.

Pollen and non-pollen palynomorph records of the Holocene part of the composite sediment core TMD from lake Tso Moriri (NW India) and of modern surface samples from the Tso Moriri region

The high-altitude lake Tso Moriri (32°55'46'' N, 78°19'24'' E; 4522 m a.s.l.) is situated at the margin of the ISM and westerly influences in the Trans-Himalayan region of Ladakh. Human settlements are rare and domestic and wild animals are concentrating at the alpine meadows. A set of modern surface samples and fossil pollen from deep-water TMD core was evaluated with a focus on indicator types revealing human impact, grazing activities and lake system development during the last ca. 12 cal ka BP. Furthermore, the non-pollen palynomorph (NPP) record, comprising remains of limnic algae and invertebrates as well as fungal spores and charred plant tissue fragments, were examined in order to attest palaeolimnic phases and human impact, respectively. Changes in the early and middle Holocene limnic environment are mainly influenced by regional climatic conditions and glacier-fed meltwater flow in the catchment area. The NPP record indicates low lake productivity with high influx of freshwater between ca. 11.5 and 4.5 cal ka BP which is in agreement with the regional monsoon dynamics and published climate reconstructions. Geomorphologic observations suggest that during this period of enhanced precipitation the lake had a regular outflow and contributed large amounts of water to the Sutlej River, the lower reaches of which were integral part of the Indus Civilization area. The inferred minimum fresh water input and maximum lake productivity between ca. 4.5-1.8 cal ka BP coincides with the reconstruction of greatest aridity and glaciation in the Korzong valley resulting in significantly reduced or even ceased outflow. We suggest that lowered lake levels and river discharge on a larger regional scale may have caused irrigation problems and harvest losses in the Indus valley and lowlands occupied by sedentary agricultural communities. This scenario, in turn, supports the theory that, Mature Harappan urbanism (ca. 4.5-3.9 cal ka BP) emerged in order to facilitate storage, protection, administration, and redistribution of crop yields and secondly, the eventual collapse of the Harappan Culture (ca. 3.5-3 cal ka BP) was promoted by prolonged aridity. There is no clear evidence for human impact around Tso Moriri prior to ca. 3.7 cal ka BP, with a more distinct record since ca. 2.7 cal ka BP. This suggests that the sedimentary record from Tso Moriri primarily archives the regional climate history.

(Table 1) Cover of shrub and tree species, and number of stems (>=3.5 cm DBH) during 1976-1977 and 2009-2010, respectively

Shrubs and trees are expected to expand in the sub-Arctic due to global warming. Our study was conducted in Abisko, sub-arctic Sweden. We recorded the change in coverage of shrub and tree species over a 32- to 34-year period, in three 50 x 50 m plots; in the alpine-tree-line ecotone. The cover of shrubs and trees (<3.5 cm diameter at breast height) were estimated during 2009-2010 and compared with historical documentation from 1976 to 1977. Similarly, all tree stems (>=3.5 cm) were noted and positions determined. There has been a substantial increase of cover of shrubs and trees, particularly dwarf birch (Betula nana), and mountain birch (Betula pubescens ssp. czerepanovii), and an establishment of aspen (Populus tremula). The other species willows (Salix spp.), juniper (Juniperus communis), and rowan (Sorbus aucuparia) revealed inconsistent changes among the plots. Although this study was unable to identify the causes for the change in shrubs and small trees, they are consistent with anticipated changes due to climate change and reduced herbivory.