Forest development, soil genesis and human activity illustrated by pollen and hypha analysis of two neighbouring podzols in Draved Forest, Denmark

A small investigation area, located in an old natural Fagus-Quercus forest, was selected for an analysis of vegetational development, soil genesis, human activity, and interaction between the processes. Podzol soils dominate the investigation area. The thickness of the humus cover varies between 5-52 cm. Two sections were excavated and material collected for pedological and microfossil analysis. Sites only 7 m apart were chosen to illustrate short-distance similarities and dissimilarities in soil development and pollen representation. Sediment accumulation curves are constructed on the basis of historical information on changes in forest composition dating back to AD 1750. Older sediments are dated from their pollen content, assuming a constant pollen influx, similar to the period AD 1750-1980. The accumulation curves reach back to the Subboreal and to the Middle Ages respectively. Relative and absolute pollen diagrams are constructed to show forest development. Concentration diagrams are calculated for the period prior to AD 1750, and an influx diagram covers the period AD 1750-1980.A primeval Tilia forest dominated the area until Late Subboreal, when human interference is first detected in one of the diagrams. Leaf-hay gathering by shredding, which did not substantially change the forest composition, was practiced until late in the Middle Ages, and the mixed Tilia vegetation persisted until about AD 1650 when the Tilia trees were felled and succeeded by a Quercus-Fagus-Betula vegetation which has dominated the area since. Changes in the use of the forest caused the death of the Tilia forest. Viscum album was present in Draved Forest until the eradication of its host. The presence of Viscum in the l6th-18th centuries indicates that this species tolerates lower summer temperature than earlier supposed. Comparison of the two percentage diagrams shows significant differences in pollen frequency, although the sites are located only 7 m apart. Similar pollen influx rates were calculated for both sites AD 1750-1980. The mean total pollen influx amounted to about 44000 pollen cm-2year-1 or 12-15000 APcorr. cm-2year-1. Distinct influx variations were recognized within smaller time units.Two types of pollen deterioration, corrosion and thinning, were distinguished and their influence on the pollen spectra analysed. The conclusion being that the pollen spectra are only slightly influenced by pollen deterioration, and differential pollen destruction does not seem to be an important source of error in pollen analysis from the raw humus stage, the arthropod humus stage, and the lumbricid humus stage. Pollen destruction was important only in the lumbricid humus stage, and both types of pollen deterioration are involved.Fungal hypha analysis includes total length measurements as well as the relative size distribution of hypha fragments. Litter composition strongly influences the annual growth of brown-coloured hyphae. The rate of litter decomposition is another important factor. The hypha production was slow in the lumbricid humus stage and accelerated in the arthropod- and raw humus stages. Hypha fragments in the soil show characteristic length-frequency distributions which indicate comminution by macro- and microarthropods during burial.The investigation has demonstrated a close relationship between soil development, forest composition and human activity. Anthropogenic disturbance and a changing forest composition accelerate soil development, which is also depending on lithology and topography. The development of a podzol was completed within a period of only 300 years in one of the sections, while it took more than 2000 years to reach the same state of maturity at the other site, only 7 m away.

Sandstones and phosphatized calcareous sediments of the Lower Cambrian Rispebjerg Sandstone, Bornholm, Denmark

The Rispebjerg Sandstone on the island of Bornholm, Denmark, consists of sandstone layers intercalated with phosphorite layers. The phosphorite lithology is composed of micritic phosphorite containing varying amounts of terrigenous grains and minor amounts of calcareous and non-calcareous allochems. Mineralogically, the micritic phosphorite is chiefly composed of carbonate-apatite, according to X-ray diffractograms. More or less complete calcite replacement by phosphate occurs both in the micrite and in the calcareous allochems. Bioturbation must have been intense as most depositional sedimentary structures have been destroyed. The most plausible explanation of the phosphorite lithology is that calcareous mud was deposited in a barred lagoon in which storms blew back sand from the barrier. Sand and mud were then mixed by bioturbation. Penecontemporaneously with the deposition of this sediment, phosphatization of calcite by phosphorous from sea water is judged to have occurred.The sandstone lithologies are calcitic siliceous submature glauconitic quartzarenite, calcitic submature quartzarenite and siliceous submature quartzarenite. Gravel-sized grains are present in the two latter sandstone types. All the sandstones are characterized by good roundness and moderate sorting. These textural parameters indicate textural inversion. The roundness is interpreted as inherited from older sediments. The sandstones may have been deposited in the tidal complex on the landward side of the sandy barrier.Scarce calcareous and phosphatic fossil fragments were locally found in rocks of all lithologies. Deposition of the Rispebjerg Sandstone was interrupted by periods of erosion, one of which originated the formation of an intraformational unconformity.Several diagenetical replacements - phosphatization, chertification, calcification, glauconitization, chloritization, pyritization - occurred during and after deposition of the Rispebjerg Sandstone.

Middle and Late Weichselian marine deposits at Nørre Lyngby, northern Jutland, Denmark, and their foraminiferal faunas

The marine Weichselian deposits at Nørre Lyngby are subdivided into four assemblage zones based on the content of benthonic foraminifera.The lowermost zone, the Bulimina marginata-Buccella frigida zone, is correlated with the upper part of the Older Yoldia Clay of Yendsyssel and inferred to be of Middle Weichselian interstadial age.The Elphidium subarcticum zone is correlated with the Lower Saxicava Sand and the Elphidium excavatum zone with the Younger Yoldia Clay of Vendsyssel. The E. subarcticum zone is found to be a sandy facies within the lower part of the E. excavatum zone at Nørre Lyngby. The foraminiferal faunas of these two zones indicate mainly artic climatic conditions. Radiocarbon dates show that the E. subarcticum zone and also a major part of the E. excavatum zone belong to late Middle Weichselian.The uppermost zone, the Elphidium albiumbilicatum zone, is correlated with the Upper Saxicava Sand. The foraminiferal faunas in this zone seem to indicate an amelioration in climate, and the deposit might be present the Late Weichselian Bølling interstadial.

The stratigraphy, structure and origin of glacial deposits in the Randers area, eastern Jutland

The investigations of the glacial sequence in the Randers area include mapping of the surface layers, study of bore profiles and detailed examination of outcrops, concentrating on the determination of transport directions in the deposits.The following stratigraphic succession has been established:Highest: NE tillTebbestrup Formation (melt water deposits)SE tillHaldum Formation (melt water deposits)Lowest: NE tillThe two uppermost units can with certainty be referred to Weichselian. Arguments are presented that the three lowermost units are of Saalian age.The origin of the sequence is discussed. The highest hills in the area (Ølst, Lysnet) were probably formed by the Saalian ice from the NE, since they appear to have influenced flow directions during the deposition of the Haldum Formation. This formation is considered to represent a sandur formed in front of the advancing ice from the SE. In the Weichselian, prior to the formation of the Tebbestrup Formation, the landscape obviously had a varied relief. The formation which infills the lower parts of this landscape is considered as a sandur, formed in front of the advancing ice from the NE. This sandur, together with the prominent hills from the Saalian, formed the substrate for the ice from the NE. This ice modified, but did not destroy the old hills.

Deglaciation landscapes formed during the wasting of the late Middle Weichselian ice sheet in Denmark

On the basis of paleoclimatological observations the thermal regime of the Weichselian ice in the Danish area is considered in this paper to have been subpolar. The glaciological and glacial-geological consequences of this concept are discussed. Contrary to current opinion it is argued that the Weichselian ice in the Danish area formed an ice sheet containing englacial debris. Observations of plains arranged in a step-like manner, of terraces in the "tunnel"valleys connected with the plains and hanging tributary valleys, and of washboard landscapes gradually passing into plains are presented. These features are interpreted as supraglacial sandurs (down-wasting plains), elongated kettles (down-wasting valleys) and Thule-Baffin moraines formed during area-wasting of the ice sheet. The ablation deposits are considered to be partially controlled by structures in the ice sheet. The topography of the substratum of the ice sheet prior to the wasting phase may have influenced the distribution and morphology of the ablation deposits. The ablation deposits appear to form a carpet over euglacial deposits like lodgement till in considerable areas of the country. The wide occurrence of separate plains and the step-like arrangement may be the result of area-wasting influenced by climatic fluctuations.

Rhaetic to Lower Liassic palynology of the onshore south-eastern North Sea Basin

Rhaetic to Lower Liassic microfloras of gymnospermpollen, microspores and aquatic palynomorphs from outcrops and cored wells in southern Scandinavia and NW Germany are investigated. 146 groups of palynomorphs, mainly species are presented from the Danish borehole Rødby 1. Based mostly on restudy of the holotypes 24 new combinations for species/varieties occurring in Rødby 1 are proposed. One new species , Corollina zwolinskai ranging from Lower to Middle Rhaetic is described.The range of polynomorphs, mainly species are noted in the wells: Rødby 1, Maasbiüll 1 and Eitzendorf 8 and in a composite section from Scania. The following miospore zones are defined: The Corollina Enzonalasporites Zone (? Norian - Lower Rhaetic), the Ricciisporites Conbaculatisporites Zone (transition (Lower-) Middle Rhaetic), the Rhaetipollis Limbosporites Zone (Middle Rhaetic), the Riciisporites Polypodiisporites Zone (Upper Rhaetic), the Pinuspollenites Trachysporites Zone (Lias alfa 1-2) and an unnamed zone with Cerebropollenites macroverrucosus (Lias alfa 3 to beta to ?, upper boundary not defined). Within the Corollina Enzonalasporites Zone the following subzones are defined: The Corollina Porcellispora Subzone, the Granuloperculatipolis Subzone and above the Enzonalasporites Conbaculatisporites Subzone. The two latter subzones are probably restricted to the Lower Rhaetic. The zones and subzones are used to correlate the mainly non marine deposits of Rødby 1, Scania, Poland and E. Germany with the more marine deposits of NW Germanu.In Scania the stratum typicum of the stratigraphically important species Limbosporites Lundbladi Nilsson is shown to be (Middle) Rhaetic. Unmixed Lepidopteris and Thaumatopteris macrofloras are of (Middle) Rhaetic and Lias alfa age, respectively.In E Germany the topmost "Middle Keuper" sensu Schulz is transferred to the Lower Rhaetic.In Poland the Drawno Beds are shown to be Lower Rhaetic and the Weilichowo Beds to be Middle (to Upper) Rhaetic.Rødby 1 is correlated lithostratigraphically with wells in NW Germany mainly on basis of the clay colours (red and green in the Lower Rhaetic, dark grey in the Middle Rhaetic, brown to light greenish grey in the Upper Rhaetic and dark grey in the basal Liassic). The lithostratigraphy agrees closely with the palynostratigraphy in Rødby 1.

The Søby Flora: Fossil plants from the Middle Miocene delta deposits of the Søby-Fasterholt area, Central Jutland, Denmark. Part II

The taxonomical treatment of the Søby Flora is continued in this work. The present paper is the second of 3 publications in which the flora will be described and the environmental and climatic conditions interpreted. A detailed description of leaf architecture and cuticular anatomy is given on the following species: Jugans acuminata Braun, Juglans juglandiformis (Sternb.) Giebel (no cuticle preserved), Alnus julianaeformis (Sternb.) Kvacek et Holy, Castanea atavia Unger, Liquidambar europaea A. Braun, Ulmus pyramidalis Goeppert and Salix lavateri A. Braun sensu Hantke 1954.

Late- and Post-glacial sediments in the Randers fjord area. Geochemical, sedimentological, and geoelectric investigations

Thickness and distribution of Late- and Post-glacial sediments in an Eastern Jutland valley system have been mapped, and their sedimentogenetic and diagenetic relations have been studied. The chemical and sedimentological methods used are discussed in detail. Post-glacial marine sediments formed in a tidal fjord environment are the most important deposits in the area, and it is shown that river supplies of freshwater control the salinity of the environment and were responsible for the rather high content of allochthonous material in the sediment. The marine sediments rest on Late-glacial sand, whose surface topography indicates that the valleys were formed by subglacial erosion. Local occurrences of dead ice were present at least until the Littorina sea (Atlantic) transgression. Depth conditions for Early Post-glacial peat are used to estimate the groundwater level and the course of the river Gudenå in the Continental Period. Sedimentary facies in the Atlantic Littorina sea are discussed, including salinity, tidal activity, water depth, nutrient conditions, and exchange of stagnant bottom water from the deepest parts of the fjord area. The sequence seems to have been influenced only by minor syndiagenetic and weathering processes.With the intention of providing supplementary information to that obtained from mapping of the Post-glacial sediments of the region 161 electric soundings have been carried out in the Randers fjord area. The specific resistivity of the sediments has been determined and the principle limitations of the methods applied have been investigated. Interpretation of the electric soundings has been done using a new system of computer programs. Maps showing the thickness relationships and variations in specific resistivity in the uppermost, largely Post-glacial deposits in the area have been prepared, and a map showing the location of the surface of the Danian limestone and occurrence of Tertiary clay is also presented.

Petrographic study of Danian limestone from eastern Denmark (Core Copenhagen TUBA 13)

Based on the investigations of thin sections, peel prints and X-ray radiographs, quantitative and qualitative data on the carbonate constituents of the Danian limestone from København are presented.The Danian limestone was classified according to both the petrographic nomenclature proposed by Folk (1962) and Dunham (1962) and to the occurrence of microborings.It is believed that on the basis of the results of the present study the problems concerning the wave and current intensities, as well as the relative depths of the formation of the Danian limestone, might be solved, through future petrographic investigations.

Foraminifera in Eemian deposits at Stensigmose, southern Jutland

The foraminiferal content of 57 samples from two sections in interglacial Eemian deposits of the cliff at Stensigmose, Broagerland in southern Jutland, have been investigated. Saalian glaciofluvial deposits and Eemian freshwater clay, underlying the marine sequence, were examined in order to check a contamination by reworked specimens from older deposits. The foraminiferal assemblages indicate that the marine sediments were deposited in shallow water. As the lower part of the strata was deposited, the water depth was increasing, but later on it was constantly decreasing. The lower part of the marine sequence was deposited during rising temperature conditions, reaching probably a little higher than today. Salinity was low throughout the deposition of these sediments, but higher than that of the present Baltic Sea.