Pollen and macrofossils profiles and age determination from three cores in Northeastern Kansas, U.S.A.

Two marshes near Muscotah and Arrington, Atchison County, northeastern Kansas, yielded a pollen sequence covering the last 25,000 yrs of vegetation development. The earliest pollen spectra are comparable with surface pollen spectra from southern Saskatchewan and southeastern Manitoba and might indicate a rather open vegetation but with some pine, spruce, and birch as the most important tree species, with local stands of alder and willow. This type of vegetation changed about 23,000 yrs ago to a spruce forest, which prevailed in the region until at least 15,000 yrs ago. Because of a hiatus, the vegetation changes resulting in the spread of a mixed deciduous forest and prairie, which was present in the region from 11,000 to 9,000 yrs ago, remain unknown. Prairie vegetation, with perhaps a few trees along the valleys, covered the region until about 5,000 yrs ago, when a re-expansion of deciduous trees began in the lowlands.

Response of marine palynomorphs to Neogene climate cooling in the Iceland Sea, ODP Hole 151-907A

The present study on ODP Leg 151 Hole 907A combines a detailed analysis of marine palynomorphs (dinoflagellate cysts, prasinophytes, and acritarchs) and a low-resolution alkenone-based sea-surface temperature (SST) record for the interval between 14.5 and 2.5 Ma, and allows to investigate the relationship between palynomorph assemblages and the paleoenvironmental evolution of the Iceland Sea. A high marine productivity is indicated in the Middle Miocene, and palynomorphs and SSTs both mirror the subsequent long-term Neogene climate deterioration. The diverse Middle Miocene palynomorph assemblages clearly diminish towards the impoverished assemblages of the Late Pliocene; parallel with a somewhat gradual decrease of SSTs being as high as 20 °C at ~13.5 Ma to around 8 °C at ~3 Ma. Superimposed, palynomorph assemblages not only reflect Middle to Late Miocene climate variability partly coinciding with the short-lived global Miocene isotope events (Mi-events), but also the initiation of a proto-thermohaline circulation across the Middle Miocene Climate Transition, which led to increased meridionality in the Nordic Seas. Last occurrences of species cluster during three events in the Late Miocene to Early Pliocene and are ascribed to the progressive strengthening and freshening of the proto-East Greenland Current towards modern conditions. A significant high latitude cooling between 6.5 and 6 Ma is depicted by the supraregional "Decahedrella event" coeval with lowest Miocene productivity and a SST decline. In the Early Pliocene, a transient warming is accompanied by surface water stratification and increased productivity that likely reflects a high latitude response to the global biogenic bloom. The succeeding crash in palynomorph accumulation, and a subsequent interval virtually barren of marine palynomorphs may be attributed to enhanced bottom water oxygenation and substantial sea ice cover, and indicates that conditions seriously affecting marine productivity in the Iceland Sea were already established well before the marked expansion of the Greenland Ice Sheet at 3.3 Ma.

Pollen records of 11 profiles from Wendland in northern Germany

1) Ingesamt 11 Profile aus sechs Mooren und Seen im Gebiet des Hannoverschen Wendlandes wurden pollenanalytisch untersucht. Die Ablagerungen umfassen den Zeitraum vom Beginn der Älteren Tundrenzeit bis zur Gegenwart. 2) Die Waldgeschichte des Hannoverschen Wendlandes weist teils Merkmale der atlantisch geprägten Gebiete Nordwestdeutschlands, teils solche des kontinental beeinflußten nordostdeutschen Raumes auf und nimmt damit eine Zwischenstellung ein. 3) Die Kiefer wandert zu Beginn der Allerödzeit ein, d.h. später als im mecklenburgisch-märkischen Gebiet und im mitteldeutschen Trockengebiet. Im Verlauf der Allerödzeit bildeten sich hier wie dort lichte Kiefern-Birken-Wälder aus. 4) In der Jüngeren Tundrenzeit fand zunächst nur eine geringe Auflichtung der Wälder statt, und die Kiefer überwog weiterhin. Erst im späteren Verlauf dieser stadialen Phase breitete sich die Birke aus und verdrängte die Kiefer. Der späte Rückgang der Kiefer stellt eine Parallele zu der Entwicklung in Südostmecklenburg und in der Altmark dar. Die Abgrenzung dieser Phasen in der Jüngeren Tundrenzeit ist durch eine 14C-Datierung gesichert. 5) Noch im Atlantikum ähneln die Diagramme aus dem Gartower Talsandgebiet im Osten des Wendlandes in ihren hohen Kiefernanteilen denen der Sandergebiete in Brandenburg. Die Diagramme aus dem Moränengebiet des westlichen Wendlandes schließen dagegen mehr an die der östlichen Lüneburger Heide und des Hamburger Gebietes an. Dieser Unterschied wird auf edaphische Unterschiede zurückgeführt. 6) Seit dem frühen Subboreal glich auch die Vegetation des Gartower Gebietes mehr den buchenarmen Waldgesellschaften auf sauren Sandböden, wie sie im atlantischen Westen vorkommen. Die Kiefern sind fast ganz aus dem Waldbild verschwunden, wobei der rasche Rückgang zu Beginn des Subboreals sicher zu einem wesentlichen Teil vom Menschen beeinflusst worden ist. Die anschließende kiefernarme Zeit dauerte im gesamten Wendland bis zum Beginn der Kieferaufforstungen in der Neuzeit. 7) In allen untersuchten Diagrammen ist etwa seit dem Subboreal eine Besiedlung nachzuweisen. Diese muß im Osten des Wendlandes intensiver gewesen sein als im Westen. Es lassen sich Phasen geringer und intensiver Besiedlung nachweisen. 8) Seit Beginn des Subboreals ist das Waldbild schon so stark vom Menschen beeinflusst, dass die Ausbreitungsgeschichte der Laubwaldarten nicht ohne Berücksichtigung der Siedlungsphasen diskutiert werden kann. Besonders im Westen bestand eine ausgedehnte Lindenphase, die durch eine Siedlungszeit (Bronzezeit) beendet wurde. Beim folgenden Rückgang der Siedlungsintensität breitet sich bevorzugt die Hainbuche aus, die dann bei der nächsten Besiedlungsphase (Eisenzeit) zurückging. Erst danach erfolgte die maximale Rotbuchenausbreitung, die nur im Westteil des Wendlandes bedeutende Ausmaße zeigte, während im Ostteil rot- und hainbuchenreiche Eichenwälder entstanden. 9) Seit Beginn der mittelalterlichen Besiedlung ist dann der Eingriff des Menschen so stark gewesen, dass die edaphisch bedingten Unterschiede zwischen Moränen- und Sandergebieten im Pollenspektrum verwischt wurden. Sowohl die buchenreichen Wälder des westlichen als auch die buchenarmen Wälder des mittleren und des östlichen Teilgebietes müssen zu fast reinen Eichenwäldern geworden sein. 10) Calluna-Heiden sind im östlichen Wendland schon in vorgeschichtlicher Zeit nachzuweisen. Im Mittelalter und in der Neuzeit treten sie im gesamten Wendland auf. Etwa im 18. und 19. Jahrhundert war die Ausdehnung der Heideflächen am größten. Erst danach wurden sie im Zuge der Kiefernaufforstungen bis auf geringe Reste verdrängt. 11) Während in der spätglazialen Vegetation Juniperus auftritt, ist der Wacholder sowohl in vorgeschichtlicher als auch in geschichtlicher Zeit - im Gegensatz zur Lüneburger Heide - wohl niemals ein Bestandteil der anthropogenen Calluna-Heiden gewesen.

Palynology on sediment profile Tso Kar in Ladakh

Palynological investigation of a 410 cm long core section from Tso Kar (33°10'N, 78°E, 4527 m a.s.l.), an alpine lake situated in the arid Ladakh area of NW India at the limit of the present-day Indian summer monsoon, was performed in order to reconstruct post-glacial regional vegetation and climate dynamics. The area was covered with alpine desert vegetation from ca. 15.2 to 14 kyr BP (1 kyr=1000 cal. years), reflecting dry and cold conditions. High influx values of long-distance transported Pinus sylvestris type pollen suggest prevailing air flow from the west and northwest. The spread of alpine meadow communities and local aquatic vegetation is a weak sign of climate amelioration after ca. 14 kyr BP. Pollen data (e.g. influx values of Pinus roxburghii type and Quercus) suggest that this was due to a strengthening of the summer monsoon and the reduced activity of westerly winds. The further spread of Artemisia and species-rich meadows occurred in response to improved moisture conditions between ca. 12.9 and 12.5 kyr BP. The subsequent change towards drier desert-steppe vegetation likely indicates more frequent westerly disturbances and associated snowfalls, which favoured the persistence of alpine meadows on edaphically moist sites. The spread of Chenopodiaceae-dominated vegetation associated with an extremely weak monsoon occurred at ca. 12.2-11.8 kyr BP during the Younger Dryas interstadial. A major increase in humidity is inferred from the development of Artemisia-dominated steppe and wet alpine meadows with Gentianaceae after the late glacial/early Holocene transition in response to the strengthening of the summer monsoon. Monsoonal influence reached maximum activity in the Tso Kar region between ca. 10.9 and 9.2 kyr BP. The subsequent development of the alpine meadow, steppe and desert-steppe vegetation points to a moderate reduction in the moisture supply, which can be linked to the weaker summer monsoon and the accompanying enhancement of the winter westerly flow from ca. 9.2 to 4.8 kyr BP. The highest water levels of Tso Kar around 8 kyr BP probably reflect combined effect of both monsoonal and westerly influence in the region. An abrupt shift towards aridity in the Tso Kar region occurred after ca. 4.8 kyr BP, as evidenced by an expansion of Chenopodiaceae-dominated desert-steppe. Low pollen influx values registered ca. 2.8-1.3 kyr BP suggest scarce vegetation cover and unfavourable growing conditions likely associated with a further weakening of the Indian Monsoon.

Early - Late Miocene palaeoclimate data and palaefloras of 48 samples from Southern China

Southern China, especially Yunnan, has undergone high tectonic activity caused by the uplift of Himalayan Mountains during the Neogene, which led to a fast changing palaeogeography. Previous study shows that Southern China has been influenced by the Asian Monsoon since at least the Early Miocene. However, it is yet not well understood how intense the Miocene monsoon system was. In the present study, 63 fossil floras of 16 localities from Southern China are compiled and evaluated for obtaining available information concerning floristic composition, stratigraphic age, sedimentology, etc. Based on such reliable information, selected mega- and micro-floras have been analysed with the coexistence approach to obtain quantitative palaeoclimate data. Visualization of climate results in maps shows a distinct spatial differentiation in Southern China during the Miocene. Higher seasonalities of temperature and precipitation occur in the north and south parts of Southern China, respectively. During the Miocene, most regions of Southern China and Europe were both warm and humid. Central Eurasia was likely to be an arid center, which gradually spread westward and eastward. Our data provide information about Miocene climate patterns in Southern China and about the evolution of these patterns throughout the Miocene, and is also crucial to unravel and understand the climatic signals of global cooling and tectonic uplift.

Pollen analysis of a sediment profile from Gabelsee in Germany

The article shows that pollen analysis plays an important role in the prediction of potential settlement areas and, furthermore, can offer a crude determination of settlement duration. Especially when the archaeological data fails to offer a possibility of dating, pollen analysis in connection with 14C can importantly broaden the knowledge base. As in the present case, the results of the Archaeo-Prognosis mapping and the pollen analysis of the Gabelsee are compared and, within this vicinity, confirmend. = Der Beitrag zeigt, dass die Pollenanalyse eine wichtige Rolle für die Vorhersage von potenziellen Siedlungsflächen spielen und darüber hinaus eine grobe Berechnung der Siedlungsdauer bieten kann. Insbesondere wenn die archäologische Datenbasis keine genaue Datierung zulässt, ermöglicht die Pollenanalyse in Verbindung mit der 14C-Datierung eine wichtige Erweiterung der Kenntnisse. Im vorliegenden Fall konnten die Ergebnisse der Archäoprognosekarte mit denjenigen der Pollenanalyse des Gabelsees verglichen und für diesen lokalen Raum bestätigt werden.

Pollen record from Blankensee, Germany

Lake Blankensee is filled with 14 m of late- and postglacial deposits, Lake Siethener See with 22,5 m. The lacustrine sedimentation begins in Lake Siethener See in the middle of the Alleröd with annual lamination which partly continues in the Younger Dryas. A 2 cm thick layer of the Laacher See tephra was found in both lakes, the Saksunarvatn tephra only in Lake Siethener See where the cool Rammelbeek-phase (Preboreal) could be shown. The youngest part of the sediment profiles is suspended drifting mud. Masses of Pediastrum (algae) indicate an increasing shoaling of Lake Blankensee after the Subboreal.

List of plant species found on Victoria Island

While engaged in geoecological field work on Victoria Island, 277 new plants could be recorded for the vicinities of Holman, Cambridge Bay, Wellington Bay, Mt. Pelly, Richardson Islands, Hadley Bay, and Minto lnlet; 8 of them were new for Victoria Island, 6 for the western Canadian arctic archipelago.

Calcareous nannofossil assemblages of Ocean Anoxic Event 2 in ODP Sites 207-1258 and 207-1260

The calcareous nannofossils of the Cenomanian/Turonian boundary interval of Sites 1258 and 1260 (Ocean Drilling Program Leg 207) have been studied in order to understand the depositional environment during Oceanic Anoxic Event 2 (OAE2) in the equatorial Atlantic. Nannofossil assemblages show a significant change in relative abundances during the positive d13Corg excursion interval. The strong increase of the high productivity indicator Zeugrhabdotus erectus and the simultaneous decrease of the oligotrophic taxa Watznaueria barnesiae and Watznaueria fossacincta are indicative of enhanced fertility. The decrease of Eprolithus floralis may be attributed to the surface-water temperature increase during OAE2, which is, however, not very significant (~2-3 °C), as suggested by published TEX86 data. It seems more likely that the decrease of E. floralis during OAE2 was evoked by the breakdown of water-column stratification, indicating it as a deep-dwelling species, which prefers stratified waters with a deep nutricline. Prediscosphaera spp. and Retecapsa ficula, which show a significant increase in relative abundances during OAE2, seem to prefer eutrophic environments, while Amphizygus brooksii and Zeugrhabdotus noeliae lower surface-water fertility. Gartnerago segmentatum, Broinsonia spp., Watznaueria biporta, and Seribiscutum gaultensis decrease in abundances during OAE2. It is not clear if they preferred an oligotrophic environment, cooler surface-waters, or if they were inhabitants of the lower photic zone. Published geochemical data suggest that enhanced fertility and higher temperatures during OAE2 may have been caused by submarine volcanic activity through the release of biolimiting micronutrients into the ocean and carbon dioxide into the atmosphere. The breakdown of water-column stratification may have increased further nutrient availability.

Pollen records from Elbe-Weser Dreieck

A long-running interdisciplinary research project on the development of landscape, prehistoric habitation and the history of vegetation within a "siedlungskammer" (limited habitation areal from neolithic to modern times has been carried out in the NW German lowlands, The siedlungskammer Flögeln is situated between the rivers Weser and EIbe and comprises about 23.5 km^2. It is an isolated pleistocene area surrounded by bogs, the soils consisting mainly of poor sands. In this siedlungskammer large-seale archaeological excavations and mappings have been performed, parallel to pedological, historical and above all pollen analytical investigations. The aim of the project is to record the individual phases in time, to delimit the respective settlement areas and to reconstruct the conditions of life and economy for each time period. A dense network of 10 pollen diagrams has been constructed. Several of them derive from the marginal area and from the centre of the large raised bog north of the siedlungskammer. These diagrams reflect the history of vegetation and habitation of a large region; due to the large pollen source area the habitation phases in the diagrams are poorly defined. Even in the utmost marginal diagram of this woodless bog, a great village with adjoining fields, situated only 100 m away from it, is registered with only low values of anthropogenic indicators. In contrast to this, the numerous pollen diagrams from kettle-hole bogs inside the siedlungskammer yield an exact picture of the habitation of the siedlungskammer and their individual parts. Early traces of habitation can be identified in the pollen diagram soon after the elm decline (around 5190 BP). Some time later in the middle neolithic period there follows a marked habitation phase, which starts between 4500 and 4400 BP and reflects the immigration of the trichterbecher culture. It corresponds to the landnam phase of Iversen in Denmark and begins with a sharp decline of the pollen curves of lime and oak, followed by the increase of anthropogenic indicators pointing to arable and pastural farming. High values of wild grasses and Calluna witness extensive forest grazing. This middle to late neolithic habitation is also registered archaeologically by settlements and numerous graves. After low human activity during Bronze Age and Older Iron Age times the archaeological and pollen analytical records of Roman and Migration periods is again very strong. This is followed by a gap in habitation during the 6th and 7th centuries and afterwards in the western part of the siedlungskammer from about 700 AD until the 14th century by the activity of the medieval village of Dalem, that was also excavated and whose fields were recorded by phosphate mapping to a size of 117 hectares. This medieval settlement phase is marked by much cereal cultivation (mainly rye). The dense network of pollen diagrams offers an opportunity to register the dispersion of the anthropogenic indicators from the areas of settlement to different distances and thus to obtain quantitative clues for the assessment of these anthropogenic indicators in pollen diagrams. In fig. 4 the reflection of the neolithic culture in the kettle-hole bogs and the large raised bog is shown in 3 phases: a) pre landnam, b) TRB-landnam, c) post landnam. Among arboreal pollen the reaction of Quercus is sharp close to the settlement but is not found at more distant profiles, whilst in contrast to this Tilia shows a significant decline even far away from the settlements. The record of most anthropogenic indicators outside the habitation area is very low, in particular cereal pollen is poorly dispersed; much more certain as an indicator for habitation (also for arable farming!) is Plantago lanceolata. A strong increase of wild grasses (partly Calluna aswell) some distance from the habitation areas indicates far reaching forest grazing. Fig. 5 illustrates the reflection of the anthropogenie indicators from the medieval village Dalem. In this instance the field area could be mapped exactly using phosphate investigations, and it has been possible to indicate the precise distances of the profile sites from the medieval fields. Here also, there is a clear correlation between decreasing anthropogenic indicators and increasing distance. In a kettle-hole bog (FLH) a distance of 3000 m away this marked settlement phase is not registered. The contrast between the pollen diagrams SWK and FLH (fig. 2 + 3, enclosure), illustrates the strong differences between diagrams from kettlehole bogs close to and distant from the settlements, for the neolithic as well as for the medieval period. On the basis of the examples presented here, implications concerning the interpretation of pollen diagrams with respect to habitation phases are discussed.

Age determination and pollen profile of sediment core Trentelmoor, Peine, northern Germany

The filling up of the lake which existed in the basin of the Trentelmoor (40 km E of Hannover, Germany) - in Preboreal times was finished 2000 years ago. Since then fen vegetation has covered the former lake's surface. The postglacial development of the vegetation follows the pattern which is typical of Central Europe. However, due to the poorness of the soils around the Trentelmoor, the frequencies of some tree species differ. Beech for example never reached - for the benefit of oak - that importance which this tree species usually gains on better soils. Human impact becomes recognisable in the upper Neolithic for the first time. The area has been settled continuously, but with changing intensities, throughout the last 3000 years. When the manuscript of this paper went to press the results of two radiocarbon age determinations only were completed. An additional three determinations were completed somewhat later. See the accompanying table for results.

Dinoflagellates of ODP Leg 104 holes

Dinoflagellate cysts, pollen, and spores were studied from 78 samples of the Eocene to Miocene section of ODP Site 643 at the outer Wring Plateau. Dinoflagellate cysts ranging from less than 1,000 to rarely over 30,000 per gram of sediment in the Paleogene, and generally between 50,000 and 100,000 in the Miocene were present. The shift to conspicuously higher cyst frequencies takes place in the lowermost Miocene section and appears to reflect increased cyst recruitment rather than a change in sedimentation rate. Of the 179 dinoflagellate cyst forms whose ranges were recorded, 129 are known species. Fifteen assemblage zones have been recognized, although the upper Eocene is missing and no substantial lower Eocene was recorded at Site 643. Norwegian Sea and Rockall Plateau zonations were compared with this study. Detailed correlation with existing onshore section zonations was difficult because key zonal species are inadequately represented; however, the middle to upper Miocene zonation established for Denmark is applicable. Pollen and spores occur with relatively low frequencies, and palynodebris is generally absent, in contrast to the observations from DSDP Leg 38. Thirty-nine samples from Eocene to Miocene sediments at Site 642 were studied and correlated with Site 643. A lower Eocene cyst assemblage present in Hole 642D is older than the questionably lower Eocene assemblage from Site 643. Site 642 has a lower Eocene to lower Miocene hiatus.