Species ldentification of Ulmus Pollen

On the basis of pore counts on modern pollen it is shown that Ulmus glabra Huds., U. laevis Pall., V. minor Mill. (U. carpinifolia G. Suchow) and U. procera Salisb. can be distinguished with some degree of certainty by their pollen. On the basis of fossil pollen it is shown that Ulmus laevis was the first elm species to immigrate into Lithuania, as has been asserted earlier, and that Ulmus glabra dominated the elm population in Atlantic time at the Danish localities investigated.

Kvartæret omkring Hobro

I 1953 besøgte jeg et par dage Nationalmuseets udgravning af vikingeborgen Fyrkat ved Hobro, og udgravningens leder, museumsinspektør, arkitekt C.G. Schultz opfordrede mig til at skrive en kort, geologisk terrænoversigt som indledning til den planlagte publikation om Fyrkat. Jeg begyndte at se mig om i egnen, men da min interesse først var fanget, tog det ene ord det andet, og det måtte nødvendigvis - for at få bund under fødderne - blive til en geologisk kartering af lidt større omfang, end jeg fra først havde troet nødvendig. C.G. Schultz døde i 1958 uden at have fået bearbejdet udgravningen af Fyrkat, og den geologiske »indledning« er nu nået til, forhåbentlig, at kunne stå alene.I terrænet omkring Mariager Fjord kendes kvartærets underlag af tertiær, danium og skrivekridt omtrent fra Skovsgård og Østpå (Victor Madsen 1918). Indenfor det her omhandlede område ligger prækvartæret imidlertid dybt. Det kendes fra tre boringer på Hvornum salthorst. Her rækker kvartæret til ca. 200 m dybde, og herunder følger muligvis tertiært sand, men i øvrigt caprock og zechsteinsalt til mindst 1550 m (DGU Boringer nr. 57. 134, 247 og 248). Tertiært ler forekommer muligvis i en boring s. f. Hvornum, men er ikke nærmere undersøgt. I alle andre boringer indenfor området ligger kvartærets undergrænse mindst 50-100 m under kote 0. De dybestliggende kvartære lag, de ældste, er altså ikke umiddelbart tilgængelige.Dette lille arbejde vil derfor i alt væsentligt beskæftige sig med de yngste kvartæraflejringer, groft udtrykt: terrænet og dets opbygning.

Clay Mineralogy of some Lower Tertiary (Paleogene) Sediments from Denmark

108 samples from the Paleogene rocks of Denrnark were examined by standard X-ray techniques and their clay suites form the basis of the present study. The X-ray data have permitted a three-fold mineralogical zonation of the Danish Paleogene.The oldest zone (Zone I) is characterized by a high montmorillonite content, minor or trace amounts of illite and segregated mixed-layer clay minerals and the absence of kaolinite. The boundaries of Zone I coincide with the Paleocene Series. The clay minerals are detrital and are derived from a carbonate terrain bordering the Fennoscandian massif. Diagenetic changes in the marine environment and segregation by sorting and floculation are important factors accounting for the high montmorillonite content.A middle zone (Zone Il) is characterized by the predominance of amorphous material. Minor amounts of montmorillonite, illite and kaolinite are present and represent alteration produets of volcanic ash. Zone II is restricted to the Mo Clay Formation.The youngest zone (Zone III) contains variable amounts of montmorillonite, illite, kaolinite and random mixed-layer montmorillonite-illite. The boundaries of Zone III appear to extend from the lower Eocene to the Miocene. The clay minerals of Zone III are products of the alteration of the volcanic material of the Fennoscandian massif. Changes in the conditions of the source area and the physical environment of deposition account for the mineralogical variations.

Pollen Analysis of the Quaternary Marine Deposits at Tornskov in South Jutland

At Tornskov 4 km north of Løgumkloster, south Jutland, a Quaternary marine deposit was found at 27-95 m below the surface. The marine deposit is covered by glacial deposits, which contain a dislocated fragment of the marine deposit. Tertiary deposits occur below 107 m. The deposits were investigated with pollen analysis. Re-deposited pollen is very frequent below 77 m. The layers at 27-77 m correspond to a major part of an interglacial succession beginning with Betula-Pinus dominance, and continuing with Alnus-Pinus dominance. Picea, Quercus, Ulmus, Carpinus, Abies, Corylus, Taxus and other trees and shrubs are represented with rather low frequencies. The interglacial marine deposit at Tornskov is contemporaneous with the interglacial marine deposit at Inder Bjergum near Ribe, and with deposits of the interglacial Holstein Sea in north Germany and the northern Netherlands, in which there is a similar vegetational development. Pollen diagrams typical of the Holsteinian Interglacial are also known from fresh-water deposits in north Germany, the Netherlands and Poland. The interglacial fresh-water deposits at Harreskov, Starup and Ølgod in western Jutland belong to another, presumably older interglacial stage.

Salt Mineralvand fra Danmarks dybere Undergrund

During the drilling operations of Danish American Prospecting Co. in Denmark 1946-1959 several mineral water occurences were encountered in the subsurface.Samples taken from Zechstein deposits show a composition ranging from concentrated almost pure MgCl2- or CaCl2-solutions to solutions more dominated by NaCl. Usually they seemn to be migrating solutions which have secondarily reacted with the salt deposits they have penetrated.Samples from Jurassic and Danian deposits are more diluted NaCl-solutions with a minor content of CaCl2 and MgCl2.The diluted mineral waters of Denmark are regarded as mixtures of concentrated salt solutions and fresh water.Uniform composition of diluted mineral waters does not necessitate a uniform composition of the original concentraled salt solutions. It may also be brought about by ion exchange reactions between clays and salt solutions of different composition as e.g. the above-mentioned solutions encountered in the Zechstein deposits.

Kvantitativ petrografisk Undersøgelse af nogle sjællandske Danienkalksten

De danske danienformationers bjergartsmæssige beskaffenhed findes som regel behandlet ret kortfattet og summarisk i den omfattende litteratur, som beskriver aflejringernes palæontologiske og stratigrafiske forhold. En mere indgående petrografisk karakterisering af bjergarterne er fremlagt i enkelte arbejder, såsom Rørdam's (1897) undersøgelse af kridtet på Sjælland, afhandlingen om Langbrogårdboringen (Madsen, Ødum, Gry, 1935) samt Gry og Søndergaard's »Flinteforekomster i Danmark« fra 1958. I sidstnævnte behandles foruden flinten også de kalkformationer, flinten optræder i.Alle hidtil offentliggjorte undersøgelser af danienkalkens lithologi og petrografi har det fælles, at de behandler emnet kvalitativt beskrivende. Formålet med de undersøgelser, som refereres i det følgende, har været at belyse, hvorvidt kvantitative petrografiske metoder giver væsentlige bidrag til karakterisering af danienkalken.

De miocæne Formationer i Danmark

The Miocene Formations of Denmark.The Miocene sediments of Denmark are restricted to the central and western part of the peninsula of Jutland. The Danish Miocene basin forms the northern part of the Miocene North Sea Basin which also covered parts of Northern Germany, Holland and Belgium. More than 200 metres of mainly micaceous clays and sands, often richly fossiliferous, were deposited. The distribution and thickness of the Miocene in Denmark is shown on the map, fig. 1, page 10.Since long the Danish Miocene has been subdivided time-stratigraphically in a Lower, Middle, and Upper division on the basis of paleontological studies by J.P.J. Ravn (1907) and Nørregaard (1916). Works by Sorgenfrei (1940, 1958) and Rasmussen (1956) recently increased our knowledge of the Danish Miocene molluscan faunas and formations.The following 6 formations are now recognized in the Miocene of Denmark (cf. fig. 7, page 41):6. Gram formation (marine). Rasmussen 1956, p. 16 (Age: Upper Miocene).5. Hodde formation (marine). This paper, p. 32 (Age: Middle Miocene).4. Odderup formation (limnic). This paper, p. 30 (Age: Middle Miocene).3. Arnum formation (marine). Sorgenfrei, 1958, p. 28 (Age: Middle Miocene).2. Ribe formation (limnic). Sorgenfrei, 1958, p. 28 (Age: Middle or Lower Miocene).1. Klintinghoved formation (marine). Klintinghoved clay, Sorgenfrei, 1940, p. 68 (Age: Lower Miocene).The type section of the Odderup formation is defined as the interval from 28,2 to 40,3 m below surface in DGU well file no. 103.50 (at Odderup Brickworks). The form ation consists of limnic sediments of quartz sands with lignite.The type section of the Hodde formation is from 13,8 to 23,4 m below surface in the well DGU well file no. 113.33 a, Hoddemark (NE of Varde). The formation consists of marine sediments of micaceous clays and sands with beds of quartz sand.The distribution of the Marine Middle Miocene of Denmark is shown on map, fig. 2, page 30 and the distribution of the Marine Upper Miocene is shown on map fig. 4, page 34.

Ivy, Mistletoe and Elm Climate Indicators - Fodder Plants. A Contribution to The Interpretation of the Pollen Zone Border VII-VIII

Knud Jessen (1935) fixed the border between his pollen zones VII-VIII which, broadly speaking, separates the Atlantic period from the Sub-Boreal period in Danish pollen diagrams, at the level "where the curve for the Oak Mixed Forest bends inwards, often because the frequency of the linden especially drops quickly".

Problems of the Early Post-Glacial Forest Development in Denmark

The present paper is a slightly extended copy of a lecture given before the Danish Geological Society January 1959. At the same meeting Dr. J. Troels-Smith read a paper, and both lectures were followed by a discussion . The author's contribution to the discussion is incorporated in the present account.As the title indicates the paper deals with problems under debate. Because the author cannot, in this brief outline, express his hesitations in every single case, he wants to emphasize once and for all that the ecological interpretations are tentative only. Yet, he thinks the questions will have to be formulated and answered ecologically. However, the answers should be checked by an independent method. Fortunately this will be possible in many cases thanks to advanced methods now to hand, e.g. exact datings by radiocarbon.A more complete discussion of the ecological background for the author's interpretation will be given in connection with a full report of our investigations in Draved forest. I take this opportunity to thank the Carlsberg Foundation for its generous support to these investigations, the present paper is largely based on experience derived from them.Most of the problems of Post-glacial forest history have indeed been discussed in the well-known books by Firbas (1949) and Godwin (1956), which in addition contain complete references. The reader is referred to these books. The drawings have been most skilfully executed by Miss Ingeborg Frederiksen.

Silicone Oil as a Mounting Medium for Pollen Grains

With the refinement of pollen analysis and with the need for more exact identifications, a number of special problems present themselves. Detailed comparative morphology becomes increasingly important and with it the requirements as to the properties of the embedding medium increase.The problems of species identifications, especially, call for a comparison of the "coarseness" of morphological details. Hence it becomes desirable that the pollen exines to be studied are found in comparable states of expansion. Chemical treatments of various kinds are well known to modify the size of pollen grains greatly, but as will be shown below the qualities of the embedding media influence their immediate state too.