the foraminifera of the lower boundary of the danish...

The Foraminifera of the lower boundary of the Danish Danian

by

J . HOFKER The Hague, Holland

A b s t r a c t

The foraminiferal sequences of faunae have been studied in series of samples taken at three localities in Denmark, where the contact between Skrivekridt (Upper Maes-trichtian) and lowest Danian is visible, viz. in a small quarry at Bjerre (Bjaerge) near Vigso, in the well-known locality Kjolby Gaard, and in the Stevns Klint, near Rodvig. In these three localities the gap between the two formations seems to be smaller than in other localities studied. The analysis of the faunae reveals a sudden change at this boundary; moreover the analysis of the orthogeneses of the pores in two Gavellinid species gave the possibility for parallelisation of formations with those of some other parts of Western Europe, and also gave information about the real significance of the so-called "Fiskeler".

Series of samples have been taken by Drs. B. J . R O M E I N and the author in many Danish localities within the scope of the project of the Dutch Commission for the Study of the Maestrichtian. Since the study of the type-localities in Holland and Belgium suggested a close resemblance of the faunae of the Maestrichtian Chalk Tuff and its boundary-formations and the Danish Danian and its underlying and overlying formations, it seems to be very opportune to know the Foraminifera of those boundaries.

The Skrivekridt-Danian boundary Danian formations always seem to lie over Skrivekridt*). However, the

age of tha t Skrivekridt not always is the same; in some localities visited, there seems to exist a larger gap between the Skrivekridt and the overlying Danian, than in other localities. The Skrivekridt found underneath the Danian in Nyvang Gaard and Rebild Bundgaard, probably also in several other localities, does not show the typical characters in its faunae of the highest Maestrichtian zone, the Pseudotextularia-zone ( H O F K E R , Die Pseudotextularia-zone der Bohrung Maasbiihl I und ihre Foramini-feren-Fauna; Palaont. Zeitschr., 30, 1956, pp. 59-79); it certainly is a slightly older par t of the Upper Maestrichtian upon which here the Danian is lying; in all such cases the typical regression-transgression zone called Fiskeler**) is missing also. At Stevns Klint, on the other hand, in some parts of the profile, well-known to geologists, the lowest zone of the Danian is missing; in such places the Fiskeler likewise is missing.

So it seems, t ha t only when a Fiskeler is present, the gap between

*) »Skrivekridt« is a Danish term for Upper Senonian White Chalk. **) »Fiskeler« is the Danish word for »Fish Clay«.

Medd. fra Dansk Geol. Forening. København. Bd. 14 [1960] 213

Skrivekridt and Danian is smallest; hence the controverses in literature about the duration of this gap; it is not in all places equally small.

Since the author believes tha t the regression-transgression zone "Fiskeler" has been caused by the same phenomenon which caused the regression-transgression zone called in Holland and Belgium the Ma ( H O F K E R , J . , Arguments for a Lower Paleocene age of the sediment above the upper M<j in the quarry of Curfs, near Houthem; Natuurhist . Maandblad, 48,1959, p . 28) and since the gap between upper Maestrichtian (Cr4) and the lowest Chalk Tuff of Maestricht (thought of the same age of the Danish Danian by the author) is very small, the author was particularly interested in the foraminiferal faunae from those localities in which a Fiskeler was developed underneath the Danian in Denmark.

ROMEIN and the author found such a Fiskeler developed in a small new quarry a t Bjerre near VigsS, North of Thisted, more to the Southwes t , in a new quarry just South of the famous locality Kjolby Gaard (only some 30 m to the South), in the latter quarry the Fiskeler itself being well-visible bu t not attainable, and in the famous locality East of Rodvig, Stevns Klint.

6' 57°

Fig. 1. Location of quarry Vigso-Bjerre (Bjærge).

19

214 J. HOFKER: The Foraminifera of the lower boundary of the Danish Danian

Fig. 2 a. The locality Vigso-Bjerre, seen from the South; of the two quarries above the horse, the most Western one is the locality.

Bjerre quarry. (Figs. l ,2a ,b ,c) . At the western part the Fiskeler is very clear, forming a clayish layer sharp with the Skrivekridt, thickness up to 10-15 cm, and covered by a more greyish clayish layer which gradually goes over in the lowest Danian, thickness about 15 cm. Below the Fiskeler which often shows parts rich in limonite and red iron ore, about 3 m Skrivekridt is visible, with a flint band. Above the Fiskeler there is about

Fig. 2 b. Locality Vigso-Bjerre, central part. Below the Fiskeler (*) and above it is a flint banc; the Bolivina basbeckensis gigantea zone is clearly seen between the Fiskeler and the upper flint banc. This zone, 90 cm in thickness on the left side of the

photograph is narrowing to the East, where it measures 30 cm only.

Mcdd. fra Dansk Geol. Forening. Kobenhavn. Bd. 14 [1960] 215

Fig. 2 c. Locality Vigso-Bjerre, detail from fig. 2 b, showing Fiskeler (*) at East side of the quarry, with many angular fragments of underlying Skrivekridt.

30 cm to 1 m Lhick Danian, then a flint band and over that band another packet of Danian, different in texture from the first layer, and thickest (about 1 m) towards the eastern part of the quarry. More to the East the Fiskeler is forming only a thin band of about 9 cm.

Two sets of samples were taken through this profile, set I in the Western part, set II in the Eastern part of the quarry (distance about 25 m).

The range-chart of Foraminifera shows, in both sets, two formations above and below the Fiskeler (Fig. 42); the highest sample taken, 990, shows a relatively poor fauna, with only rare specimens, obviously reworked, of a very typical species, Bolivina basbeckensis gigantea nov. subsp. It is very abundant in the layer above the Fiskeler, and is characteristic here,

19*

216 J. HOFKKR: The Foraminifera of the lower boundary of the Danish Danian

Set I. (Fig. 45) Set II . (Fig. 45) 971 just below upper flint, soft

marl 972 15 cm below 971 soft marl 973 15 cm below 972 hard marl 974 just above Fiskeler marl 970 grey clayish layer above Fiske-

ler 969 Fiskeler with limonite 975 just below Fiskeler, hard white

Skrivekridt 976 just above flint layer in the

Skrivekridt 977 in flint layer 978 just below the flint layer 979 soft chalk with rich fauna 980 15 cm below 979 hard chalk 981 15 cm below 980 hard chalk 982 15 cm below 981 hard chalk 983 lowermost sample, rich fauna

990 80 cm above flint layer in Danian, 20 cm below second flintlayer

989 30 cm above flint layer in the Danian

988 25 cm above the Fiskeler 987 Fiskeler, a thin marl band 986 40 cm below Fiskeler 985 80 cm below Fiskeler

in Kjolby Gaard and in Stevns Klint. The chalk above the highest flint-layer, not sampled here, but given in a series of samples from Kjolby Gaard, contains not this species and is very poor in specimens of Foraminifera. In the chalk above the Fiskeler typical other species are Globigerina daubjergensis primitiva nov subsp., a very small form, without any sutural openings, and Tritaxia danica nov. spec.

The Fiskeler itself and the greyish clayish layer above it contain only smaller species reworked from the underlying Pseudolextularia-zone of the Skrivekridt; moreover there is abundance of fish-scales. In those Fiskeler-samples in the range-chart we do not find any of the species typical for the Danian above; obviously tha t Fiskeler was laid down before the Danian sediment and before the Danian fauna appeared. Moreover the state in which the tests are found in the Fiskeler does not suggest a strong deplacement of these tests, bu t for the upper part , a light grey marl; it seems, as if these tests were just rests of suddenly killed animals, killed together with the many fishes; moreover, small fragments of Skrivekridt in the Fiskeler never are ground, they all show a rough and broken surface. These phenomena are quite identical with those found in the Ma

beneath the Maestrichtian Chalk Tuff in Holland; here also well-preserved reworked species from the underlying Cr4 (high Maestrichtian) together with many rests of Echinoderms, fishes, etc., are found. The author believes tha t we have here the remains of a sudden regression of the sea; and the rests of the animals, dried in the sun or killed by a glaciation, were gathered up when, soon afterwards, the sea transgressed again, without much disturbing its former bottom, and not transgressing over its former borders either, but for the time in which the upper part , greyish marl, was sedimented.


Below the Fiskeler, the Skrivekridt shows the fauna of the Pseudotextularia-zone; the highest part of it lacks the planctonic forms, and is nearly identical in its fauna with the Dutch-Belgian Cr4, the coastal facies of the Pseudotextularia-zone; the only difference is found in the occurrence in Denmark in nearly all samples of Stensioina esnehensis, which does not occur in Cr4 in Holland, bu t is found in the basal conglomerate of the Tuff eau de Saint Symphorien in Southern Belgium, and its equivalents in the hollows of the hard grounds in Northern Belgium; they are of the age of the upper par t of the Pseudotextularia-zone in Denmark. The marking species of the Pseudotextularia-zone are Bolivina hiltermanni, Orbignyna rimosa and O. ovata compressa nov. subsp., Gavelinopsis barten-steini, Stensioina esnehensis, Praebulimina carsegae, Gavelinopsis ventricosa, and, in the lower samples, Neoflabellina postreticulata and Pseudotextularia varians. I t is a remarkable fact, t ha t both in the Cr4 in Holland and in the Pseudotextularia-zone in Denmark, Bolivinoides gigantea is not more found in the higest part , nor is Neoflabellina postreticulata; these species, together with Bolivinoides draco (which does not occur in the higher Maestrichtian in Holland and Belgium) extinguish already during the Pseudotextularia-zone. In this way, Bolivinoides gigantea is not found in the sets taken at Bjerre, and they do not occur either in the highest levels of the Pseudotextularia-zone in Kjolby Gaard and in the quarry "Dania" . Globotruncana citat, a typical species of the more planctonic facies of the Pseudotextularia-zone, appears at Bjerre likewise in the deeper samples.

So we may conclude, tha t at Bjerre the top of the Skrivekridt already was more coastal (or the sea too cold), to begin with sample 978; at the end of the Maestrichtian the sea began to retreat ; this retreat ended with a sudden disappearence of the water over large areas.

Fig. 3. Location of Kjolby Gaard near Hunstrup.

Kjolby Gaard. (Fig. 3 and 4). Jus t South of the original quarry as figured by ODUM, 1926, fig. 11, a new very high and steep wall is now laid open; the quarry shows a large par t of the Skrivekridt, about 7 m of it, in which, about 5 m above the base of the quarry, a single more greyish and more clayish layer is found, the "Kjolby Gaard mar l" of TROELSEN (TROELSEN, J . C , Globotruncana contusa in the White Chalk of Denmark; Micropaleon-tology, 1, 1955, pp . 76-82). Above this layer (thickness about 40 cm) 11,5 m of white chalk are seen, covered by a double flint band; this double band is covered by 4 m chalk which seems slightly more yellow; then there is a dark band with somewhat irregular surface, and on top 1,25 m

21 8 J. HOFKER: The Foraminifera of the lower boundary of the Danish Danian

Fig. 4. Locality Kjolby Gaard. + Kjolby Gaard marl. * boundary between Skrivekridt and Danian.

yellowish chalk. We could not sample the whole profile; samples were taken below the Kjolby Gaard marl,till 4 m above it ; a grove was made aside from the quarry, and several samples were taken just underneath also; thus, at least 6 m of Skrivekridt were not sampled, and the Fiskeler was not attained either; yet it seems that the lowest sample of the series near to the top was slightly above the Fiskeler, since the samples 955-956 and 957 contain Bolivina basbeckensis gigantea.

The diagram (Fig. 43) shows, tha t all samples taken near the top are Danian; the highest samples contain Tritaxia danica, Karreria fallax, Gavelinopsis constricta, Globig. pseudobulloides. But only the lowest three of

Mcdd. fra Dansk Geol. Forening. København. Bd. 14 ]1960] 219

Sampling Kjolby-Gaard (Fig. 43)

958 highest sample in the grove 959 20 cm below 958 960 between two thin flint banks 961 in the lowest flint bank 962 deepest sample in the grove; 958-962 cover l,oo m 954 sample taken at the west border of the quarry, about between 961.

and 962 955 about 2 m below 962 956 about 50 cm below 955 957 about 50 cm below 956 968 4 m above the Troelsen layer 967 3 m above the Troelsen layer 951 highest par t of Troelsen layer 952 10 cm below 951, in the Troelsen layer 953 10 cm below 952, in the Troelsen layer 966 1 m below Troelsen layer 965 1 m below 966 964 1 m below 965 963 1 m below 964

them contain the typical fauna from just above the Fiskeler a t Bjerre, viz. Bolivina basbeckensis gigantea, Gaudryina faujasi, Globigerina daubjer-gensis primitiva, so tha t here, just as in Bjerre, the lowest Danian is divided into two successive parts , the lower one with Bolivina basbeckensis gigantea, and the upper one, without it. Jus t as in Bjerre, we find tha t in the upper par t of the Skrivekridt, Bolivinoides gigantea is missing, together with Bolivinoides draco; moreover, Pseudotextularia varians is not found in the highest sample, nor are Globotruncana citae and G. intermedia. Here too it seems tha t towards the top of the Skrivekridt, the fauna more and more gets a coastal character (or a colder one).

In the layer of TROELSEN, the "Kjolby Gaard marl" , we find some species which otherwise in the Pseudotextularia-zone are missing: Globotruncana contusa (CUSHMAN) and Spiroplectammina dentata ( A L T H ) . The latter species is the more conspicuous one, since it also occurs in the "Blaakridt" layers where Globotruncana contusa is missing, e.g. in the "Dania" Chalkworks. Moreover, the layer is very rich in individuals of Bolivinoides gigantea and B. draco.

In Kjolby Gaard, the Globigerina contusa zone is found within the Pseudotextularia-zone, characterised by typical southern species, for also Spiroplectammina dentata is a typical Thetys species. In the "Dania"-works we find a similar layer, lacking Globotruncana contusa, bu t containing many specimens of Spiroplectammina dentata; but here this layer seems to lie just at the lower boundary of the Pseudotextularia-zom.

Stevns Klint (Fig. 5 and 6a, b). Here the situation is somewhat different from tha t in the Thisted-region. The Skrivekridt shows a t its top a slightly hardened layer, but soft enough to extract its fossils. In some parts a Fiskeler is developed not differing from tha t found in the Nor th ; in tha t

220 J. H O F K E R : The Foraminifera of the lower boundary of the Danish Danian

Hojerup

16' 55°

•~/fæf/esskoy fiev

0°l 12' 0° 6 '

Fig. 5. The locality in which the samples 1050-1055 were taken at Stevns Klint (near Korsnæb).

case, above the Fiskeler a layer is found which shows the fossils as found in the lowest part above the Fiskeler in the Thisted-region: Bolivina basbeckensis gigantea and Tritaxia danica, together with primitive Globi-gerina daubjergensis (Fig. 44, range-chart). In other parts this layer seems to have been swept away by the next formation or never was formed, and in that case the Fiskeler is also absent; Allomorphina paleocenica, Globigerina daubjergensis and a peculiar primitive form which may have led to Globigerina pseudobulloides, G. cf. quadrata "WHITE, without the typical lip at the aperture as found in G. pseudobulloides, are abundant. Moreover, we find here bryozoic limestones, which are not found in the Thisted area, above the Bolivina basbeckensis zone. There also is another difference; in both cases in Stevns Klint the Skrivekridt just underneath the Danian, does not show the coastal facies, but the Skrivekridt ends here with a typical pelagic facies, since till in the top-layers Pseudotextularia varians and Globigerina rugosa are found. Moreover, while in the Thisted area no holes are found below the Fiskeler, here holes occur underneath the Fiskeler as well as underneath the Bryozoan chalk, both into the Skrivekridt. The holes underneath the Fiskeler (sample 1056; Fig. 45) show the fauna from the Fiskeler as well as the Bolivina basbeckensis fauna; the holes found underneath the Bryozoan chalk show the fauna of a typical higher Danian (sample 1055). There is quite a difference between the two kinds of holes; those showing the Bolivina basbeckensis fauna are narrow, and coated with flint; those containing the Allomorphina-Nodosarella paleocenica fauna are wider and not coated, but filled, between the marly material, with irregular flint particles. May be, that there is a connection between the uppermost fauna at Kjolby Gaard, and the fauna with Allomorphina paleocenica; there also an Allomorphina is found tending to


Fig. 6 a. Stevns Klint near Korsnæb. The Fiskeler (*) at the right here is covered by a thin layer of Bolivina basbeckensis gigantea zone, but to the left this zone is mis

sing, and the Fiskeler also.

halli, and the Dentalina basiplanata found there has already characters of Dentalina colei found in the Allomorphina paleocenica fauna. In any case it will be clear from what was found in Stevns Klint, tha t :

a. the gap between Skrivekridt and Danian here is larger than it is in the Thisted region: holes in a hard ground; coastal part of Skrivekridt missing;

b. the two Danian faunae found, the one above the other, in the Thisted region more or less are found in Stevns Klint also (though the upper one in a different facies), whereas these two formations must be separated from each other as distinct formations, since they also may occur the one without the other, as in Stevns Klint. In the Stevns Klint region they have been separated from each other by W I N D as zones I and II. There is strong evidence for distinguishing these two zones also at Kjolby

222 J. HOFKER: The Foraminit'era of the lower boundary of the Danish Danian

Fig. 6 b. Stevns Klint, near Korsnæb. Part, where the Fiskeler is absent, and also the Bolivina basbeckensis gigantea zone; here already younger Danian rests on the Skrivekridt, and in the wide holes underneath the contact (-> ^ ) only material from the higher zone is found. The stamp gives the real measures. The photograph

has been taken after the picking out of the holes.

Gaard and Bjerre, and here they seem to be separated by a distinct flint banc.

There is in all profiles studied a zone above a distinct Fiskeler, in which species occuring already in the Skrivekridt, continued to live; they are not reworked, for in tha t case many other common species of the Skrivekridt also would be found; at the end of this period they vanish totally, while other species, such as Stilostomella spinosa, Gavelinella pertusa maeslrich-tiensis, Marssonella oxycona, outlive in higher Danian also. Quite the same is found in the formations just above the regression-transgression zone in Holland, the Ma; in the lower Mb, we find several typical species from the white chalk continuing, often occurring abundantly, and not reworked either; but only few of them continue in higher levels.

Medd. fra Dansk Geol. Forening. København. Bd. 14 [1960] 2 2 3

Fig. 7. Bolivinoides gigantea HILTERMANN and KOCH. Kjolby Gaard, sample 951, upper part of Kjolby Gaard marl ; x 4 0 .

- 8. Bolivinoides australis EDGELL. KjSlby Gaard, sample 965, below Kjolby Gaard marl; x 4 0 .

- 9. Spiroplectammina denlata (ALTH). Kjolby Gaard, sample 953, lowest part of Kjolby Gaard marl; a, sideview; b , apertural face; X40.

- 10. Bolivina (Loxostomal) selmaensis CUSHMAN. Stevns Klint, sample 1050, Skrivekridt just below Fiskeler; a, broad side; b , narrow side with the peculiar aperture; x 4 0 .

- 11. Pseudotextularia varians RZEHAK. Kjolby Gaard, sample 953, Kjolby Gaard marl; x 8 5 .

- 12. Allomorphina halli JENNINGS. Stevns Klint, sample 1050, Skrivekridt just below Fiskeler; from two sides; this is the form with 4 chambers in the last formed whorl; gradually, during the Danian and the Maestrichtian Tuff Chalk this form changes, having in the lower Paleocene only 3 chambers in the last formed whorl; x 8 5 .

- 13. Globigerina cf. linaperla FINLAY. Stevns Klint, sample 1050; this form always shows 4 chambers and is not a t all identical with any Cretaceous Globigerina; it also occurs a t the top of the Cr4 in Holland; x 85.

2 2 4 J. H O F K E R : The Foraminifera of the lower boundary of the Danish Danian

Fig. 14. Globigerina rugosa PLUMMER. Stevns Klint, sample 1050; upper Skrivekridt; characteristic are the strong tena over the umbilical hollow; x 85.

- 15. Slensioina esnehensis NAKADY. Stevns Klint, sample 1050, upper Skrivekridt ; the species may be very close to S. excolata (CUSHMAN), but seems to differ from it having also pores at the dorsal side; a, dorsal side; b, apertural face; c, ventral side; x40 .

- 16. Bolivina basbeckensis H O F K E R gigantea nov subspec; Kjolby Gaard, sample 955, just above the Fiskeler; a, generation A2 ; b, generation A t ; c, generation B ; x 4 0 .

- 17. Gavelinopsis conslrictus (REUSS) . Same locality as Fig. 16; a, dorsal side; b, apertural face; c, ventral side; X40.

- 18. Giimbelina globulosa (REUSS) . Vigso-Bjerre, sample 975, Bolivina basbeckensis gigantea zone of the Danian; the species is extremely common here and seems not to be reworked; such specimens also are found in the Maestrichtian Chalk Tuff; x 8 5 .

- 19. Globigerina biforaminata HOFKER. Vigso-Bjerre, sample 975, see above; very common and not reworked; from three sides; such specimens also occur in the lowest Maestrichtian Chalk Tuff; x 85.


Fig. 20. Globotruncana citae BOLLI. Kjolby Gaard, sample 967, Skrivekridt; this species with its nearly closed umbilicus and more sutural aperture with tenon, clearly seen in c, has been.given a new generic name, Abathomphalus, by BOLLI, LOEBLICH and TAPPAN; it clearly forms the transition from Globotruncana toward Globorotalia; a, dorsal side; b, from aside; c, ventral side; x 85.

- 21. Globotruncana (Marginotruncana) intermedia BOLLI. Vigso-Bjerre, sample 978, upper Skrivekridt; a, dorsal side; b, from aside; c, ventral side; x 8 5 .

- 22. Globotruncana (Marginotruncana) contusa (CUSHMAN). Kjolby Gaard, sample 953, Kjolby Gaard marl; a, dorsal side; b , from aside; c, ventral side; X85.

Especially G. citae and G. intermedia are nearly always found in the upper layers of the Skrivekridt; though they are planctonic forms, they never are found in reworked state in the Bolivina basbeckensis gigantea zone of the Danian; however, many other planctonic species, designated as typical "Cretaceous", occur very commonly in that zone as well as in the zone next to i t ; this seems to indicate tha t the latter species are not reworked from the Skrivekridt, but continued for some time after the Fiske-ler phenomenon.

2 2 6 J . H O F K E R : The Foramihifera of the lower boundary of the Danish Danian

Fig. 23. Tritaxia danica nov. spec. Kjolby Gaard, sample 955, above the Fiskeler, Bolivina basbeckensis gigantea zone; a, angled side; b, flat side; c, apertural face; typical is the elongate aperture; x40 .

- 24. Globigerina rugosa PLUMMER. Bjerre, sample 975, just above the Fiskeler; such forms, with strongly formed ridges on the surface, are not found in the upper Skrivekridt, nor, reworked, in the Fiskeler; so it is not a t all certain that they are reworked; they are typical for the Bolivina basbeckensis gigantea zone; a, dorsal side; b , from aside; c, ventral side with the typical overlapping tena; x85 .

- 25. Globigerina daubjergensis BRONNIMANN primiliva, nov. subspec. (?). Vigso-Bjerre, sample 975, Bolivina basbeckensis gigantea zone; such specimens are always found in the samples of this zone, and, even with high magnifications, and in a clarifier, do not show any traces of dorsal sutural openings; yet they seem to form the first stages of G. daubjergensis; they may be related to one of WHITE 'S species from the Velasco; x85 .

- 26. Glob. pseudobuUoides PLUMMER. Vigso-Bjerre, sample 975, see above; such specimens also are found at the boundary Cr4-Maestrichtian Chalk Tuff, in Holland, and seem to have derived from forms common in the upper Pseudo-textularia-zone; X 85,.


Fig. 27. Globigerina cf. quadrata W H I T E . Same sample; these forms may be the first stages of later Globigerina pseudobulloides; they miss the lip over the aperture, and are very common; x 8 5 .

- 28. Globigerina cf. linaperta FINLAY. Same sample, smaller form; x 8 5 . - 29. Nodosarella paleocenica CUSHMAN and TODD. Stevns Klint, sample 1055,

second zone of the Danian; this species seems to be identical with N. paleocenica from CUSHMAN and T O D D , and is characteristic for its stoutness; i t is found in many samples from that zone; x40 .

- 30. Allomorphina paleocenica CUSHMAN. Stevns Klint, sample 1055; this species occurs abundantly in the Maestrichtian Chalk Tuff, and also is found in many other Danian samples in Denmark; it is a stout form, characterised by the somewhat pointed last formed chamber; a, dorsal side; b, from aside; c, ventral side; x 40.

- 31. Glob, pseudobulloides PLUMMER. Stevns Klint, sample 1055, second zone of the Danian; a, dorsal side; b, apertural face; c, ventral side; x 8 5 .

- 32. Globigerina spec. A smoothly finished not uncommon species in zone II of the Danian; same sample, Stevns Klint; a, dorsal side; b, from aside; c, ventral side; pores very fine; it may be the first stage of Glob, triloculinoides PLUMMER, as will be explained in another paper; x 8 5 .

2 2 8 J . H O F K E R : The Foraminifera of the lower boundary of the Danish Danian

Fig. 33. Globigerina pseudobuHoides PLUMMER. Stevns Klint, sample 1055, zone II of the Danian; here a spiall lip over the aperture is found; yet it is quite uncertain, •whether the species belongs to primitive forms of G. pseudobuHoides or of G. triloculinoides; the pores are fine, whereas in triloculinoides they are quite distinct; X89.

- 34. Globigerina daubjergensis BRONNIMANN primitiva nov. subspec (?). Stevns Klint, sample 1059, zone I I ; common form, without any trace of sutural openings; x 8 5 .

- 35. Globigerina supracretacea HOFKER. Same sample; this species also is found in the lower part of the Maestrichtian Chalk Tuff, where i t is not uncommon; a, dorsal side; b, from aside; c, ventral side; x 8 5 .

- 36. Globigerina cf. daubjergensis BRONNIMANN. Same sample, Stevns Klint; No trace of sutural openings; x 8 5 .

- 37. Giimbelilria mauriciana COLE. Stevns Klint, sample 1055, zone I I ; a common form, also found in the Maestrichtian Chalk Tuff in Holland; x 85.

- 38. Giimbelina wilcoxensis (CUSHMAN & PONTON). Stevns Klint, same sample; X85.

- 39. Giimbelina globulosp. (REUSS) . Stevns Klint, sample 1055, zone I I ; x 8 5 .


Nevertheless, in both formations, Ma in Holland and Fiskeler in Denmark, there is the striking and sudden planctonic faunal break; after the regression-transgression zones, we find a short period in which some planctonic forms outlive; but soon afterwards the typical "Ter t iary" planctonic forms begin; during the period of the Maestrichtian Chalk Tuff and during t ha t of the Danian, the planctonic forms show identical stages of development ( H O F K E R , J., On the development stage of Globigerina pseudobulloides PLOMMER in the Maestrichtian Chalk Tuff; Natuurhist . Maandblad, 48, 1959, pp. 80-83).

C o n c l u s i o n : the phenomena which led to the forming of the Ma in Holland and Belgium, and to the Fiskeler in Denmark, were identical phenomena, in genesis as well as in time (Fig. 46).

F o r a m i n i f e r a l z o n e s

Danian; zone without Bolivina basbeckensis gigantea; with Globigerina pseudobulloides and G. daubjergensis prim.

Danian; zone with Bolivina basbeckensis gigantea; with Globigerina pseudobulloides and G. daubjergensis primitiva.

Fiskeler; zone with reworked Foraminifera from the Skrivekridt. Skrivekridt; zone with Pseudotextularia varians and Stensioina esnehen-

sis; Bolivinoides gigantea; upper par t often without planctonts. Skrivekridt; zone with Pseudotextularia varians and Globotruncana con-

tusa; always with Spiroplectammina dentata (Kjolby Gaard marl). Skrivekridt; zone with Pseudotextularia varians or a slightly older zone

without it ("Dania"-works); Bolivinoides australis.

Remarks on markers of the different zones

Pseudotextularia-zone Bolivinoides australis and Bolivinoides gigantea (Fig. 7, 8). Both belong

to the Bolivinoides decorata-gigantea gens ( H O F K E H , J., The gliding change in Bolivinoides during t ime; Natuurhist . Maandblad, 47, 1958, pp. 145-159); Bolivinoides australis differs from the higher developed form gigantea in having at least in the first par t of the test the costae divided into small pustules. In sample 965, Kjolby Gaard 2 m below the zone of TROELSEN, it shows an average of pustules at the last formed chamber of 6,5; this number points to the lowest pa r t of the Pseudotextularia-zone,

Fig. 40. Globigerina pseudobulloides PLUMMER primitiva nov. subsp. (?). Stevns Klint, sample 1055, zone II; such specimens show a very small lip over the aperture, and thus may be primitive forms of G. pseudobulloides PLUMMER; X 8 5 .

The whole fauna of zone II, and also the more Tertiary species of zone I resemble the assemblage as found in the "Velasco as described by WHITE (WHITE, M. P., Index Foraminifera from the Tampico Embayment, Journ. Pal., 2, 1928, pp. 192-196); there are specimens resembling G. quadrata WHITE, others related to G. triangularis (fig. 36); some are very close to G. velascoensis WHITE (fig. 34), and others to G. mackannai WHITE (fig. 35); fig. 32 might also called G. belli WHITE; the rough forms of the daubjergensis type seem close to WHITE'S G. bulloides. Several authors believed that the "Velasco, at least its lower part, belongs to the Danian period.

20

2 3 0 J. H O F K E R : The Foraminifera of the lower boundary of the Danish Danian

identical with the lowest Craie tuffoide in the drill-hole at Glons, Belgium. In the Kjolby Gaard marl in Bolivinoides gigantea, with ribs all over the surface of the test, this number has increased up to 8; tha t is the number typical for the middle and upper par t of the Pseudotextularia-zone and also of the higher par t of the Craie tuffoide or Cr4 in Holland and Belgium. This identification of Pseudotextularia-zone, Craie tuffoide and Cr4 leaves no doubt as to the contemporaneity of these formations. In the highest samples, under the Fiskeler and below the Ma in Holland, Bolivinoides gigantea has disappeared for ever; so it is obvious tha t also the highest par t of the Pseudotextularia-zone, when undisturbed and fully developed, corresponds with the highest par t of the Cr4 in Holland ( H O F K E R , J., The age of the Cr4, Craie tuffoide; Natuurhist . Maandblad, 48, 1959, pp. 46 -50).

Globotruncana contusa (CUSHMAN) (Fig. 22) in Kjolby Gaard (Kjolby Gaard marl) is smaller than observed in many localities over the world; it must be emphasized, that such flattened specimens also occur in the Cr4 (Craie tuffoide) a t its top ( H O F K E R , J., Planctonic Foraminifera in the Chalk Tuff of Maestricht and environments; Natuurhist . Maandblad, 45, 1956, pp. 51-57). Also TROELSEN mentions from this layer agglutinated Foraminifera which use quarz-grains; this refers to Orbignyna ovata com-pressa and Spiroplectammina dentata ( A L T H ) ; the latter is typical for the layer, the former occurs through the whole Pseudotextularia-zone.

Spiroplectammina dentata (ALTH) (Fig. 9). A species with a triangular test, thickest in the median line, with distinct sutures which are compressed, and a dentate margin. The fine agglutination consists, contrarily to Sp. laevis, of quarz grains. I t is common in the Maestrichtian of Southern Europe, and is found in layers which indicate a southern intrusion of species.

Orbignyna ovata (HAGENOW) compressa nov. subspec. ( H O F K E R , Pseudotextularia-zone, Pal. Zeitschr., 1956, pi. 5, fig. 3). The forms are much compressed, with distinctly compressed sutures and thus differ from the older types. It is typical for the Pseudotextularia-zone, and in its higher parts only two forms are found, the long fusiform B-form, and the compressed A-form. The aperture here becomes complex and forms a row of openings in the apertural face. The inner structure is pseudo-labyrinthic. It mostly occurs together with the latest form of Orbignyna rimosa (MARSSON) which is distinguished by the agglutination by many sponge-spicules. Its A-form here often becomes very large (1. c , pi. 5, fig. 1).

Bolivina (Loxostoma) selmaensis CUSHMAN (Fig. 10). This short species is characterized by its broad form, smooth sutures, strongly oblique chambers, often pointed at the aperture, and acute margin, and the peculiar aperture ( H O F K E R , 1. c , 1956, pi. 7, fig. 35); it is believed to form one of the most typical markers of the highest Maestrichtian.

Pseudotextularia varians RZEHAK (Fig. 11) is not always present in the samples of the zone named after this fossil; it fails in the highest par t of it at. Bjerre as well as a t Kjolby Gaard. I t fails nearly in all samples of a large series taken through the zone in the quarry "Dania" , and is not found in the equivalent of the zone in Holland and Belgium. When it is

Medd. fra Dansk Geol. Forening. Kobenhavn. Bd. 14 [1960] 2 3 1

not found in a whole formation or larger part of it, this formation must have been sedimented near the coast, where the southern stream in the sea did not exert its influence. Globotruncana citae (Fig. 20) and G. intermedia (Fig. 21), both from BOLLI , only are found in real open sea sediment; they are characteristic for the zone ( H O F K E R , 1956,1. c ) . So it seems tha t the southern stream carrying those planctonic forms not always was equally strong or reached all parts of the sea. This quite reminds of what is known from the recent Gulf Stream. All other species from the Pseudo-textularia-zone have been described and figured already in my paper on tha t zone, mentioned above; very typical for all samples is Stensioina esnehensis NAKADY, characterised by the overlapping chambers at the dorsal side so tha t the last formed whorl is a very broad one, by the occurrence of pores also in the dorsal wall and a complex aperture. Even in those samples in which no planctonic species occur, Stensioina esnehensis is found; this is the main difference with the Cr4 from Holland and North East Belgium, where the species until now was not found; but it occurs in Belgium in equivalent formations more to the South. Bolivina basbeckensis is rare in the samples of the Pseudotextularia zone in Denmark, though it occurs in the lower beds of it. This is remarkable, for we will find its latest development stage very commonly in the lowest Danian bed, so tha t a reworking of tha t species there from underlying Skrivekridt is impossible. I have, in the range charts, not separated Bolivinoides dorreeni from Bolivinoides draco; they occur in the higher levels together, and many stages of dorreeni cannot be clearly separated from outgrown draco. It is a conspicuous fact t ha t Bolivinoides paleocenica is rare in the Skrivekridt beds in Denmark, especially in those from the North; yet the species is found abundantly in several zones of the Danian; so they cannot be reworked there either.

During the Pseudote'xtularia-zone, Neoflabellina postreticulata H O F K E R reaches, just as in the Cr4 in Holland, its utmost development stage; Neoflabellina numismalis ( W E D E K I N D ) is found, somewhat rarely, in this zone and is the only species of Neoflabbellina which finds its later development stages above the Fiskeler, since it reaches into the Danien up into the Middle Danian, where it is not uncommon. This is one of the many Cretaceous forms which continue in the Danian. Gavelinonion nobilis (BROTZEN) beginning its development in the lower Upper Maestrichtian and already common in the upper lower Maestrichtian as a totally trochoid form, in the Pseudotextularia zone continues its development, and is found nearly planispiral in the Danian and in the Paleocene above as a totally planispiral form with affinities to Gavelinonion affinis ( R E U S S ) . In the upper layers we find Gavelinella umbilicatiformis and Gavelinopsis involuta, both continuing through the Danian and ending their development in the lowest Paleocene, just as is found in Holland, where they occur in the upper Cr4, and continue till into the uppermost Maestrichtian Chalk Tuff, with quite the same orthogeneses.

I t is interesting tha t in the upper Pseudotexlularia-zone, Osangularia lens, common in the lower part , is not found in Vigso-Bjerre, probably neither in Kjolby Gaard. Yet it is very common in the whole Danian.

20*

232 J. HOFKER: The Foraminifera of the lower boundary ol the Danish Danian

This, together with what has been said about Bolivina basbeckensis gigan-tea, would mean tha t the sea, regressed at the Fiskeler-time, with its return must have come from a different par t of the ocean.

The pore-diameter orthogeneses at the boundary and in the Pseudotextularia-zone

The author has proved that many species of the Gavelinellidae during geologic time show an increase in their diameters of pores; this statement has resulted in applying these changing diameters in stratigraphic questions. ( H O F K E R , J., 1. Foraminiferen der Oberkreide von Nordwest-deutschland und Holland, Geol. Jahrb . , 1957, Beih. 27, pp . 370-374; 2. Species Of the genera Gavelinella and Gavelinopsis in the Cretaceous above the Hervian in Germany, Holland and Belgium, and the increase of the diameters of their pores as indication for stratigraphic levels, including the development of the pores of some Stens joma-species, Natuur-hist. Maandblad, 45, 1956, pp. 99-110, with range-chart; 3. Orthogenesen von Foraminiferen, Neues Jahrb . Geol. Pal., Abh., 108,1959, pp. 239-259).

The specimens are imbedded in Castor-oil (Rhicinus-oil), and, when filled not with air bu t with chalk, which makes pores difficult to see, crushed between two object-glasses. Pores are drawn by means of an Abbemirror, and the drawings measured; best enlargement is 500 x .

In the samples from Vigso-Bjerre and from Kjolby Gaard from Pseudotextularia-zone and Fiskeler, in this way pores were measured from Gavelinopsis bartensteini and from Stensioina esnehensis. The results are tabulated on fig. 41.

"a.

4

970 989 975 976 977 978 979 981 982. 983

968 967 953 966 967

Stensioina, esneh« Tl 1818 9

1013116171 618122412

3 1*15 7 4 31310 7 6 202213 812 2. 6 1621710 2 15 3518 10 5 71910 6 4

6 S 3913

w i l l fium. 8 5019 3 1 1863244 1 8 31219 6

3195812 964 2193924

! 2,53 354 4,5 5 5,566,5 3 Porc.citLmeUrs in yu.

V i q s b _ Bjerre.

inei-s 3,7 5,3

• 5,6 5,6 SØ 47 52 4B 4,7 4,0

K j o l b y G u r d .

4,1 4,1 4J

Qa.treUnopsis 1>a.rten<tein£ 4 2 0 TI 1

2110 4 1 9 13 9

5 5 TI 716 3 121410 2110 2

41419 9 132 2 11 9 13257 2 33221416 2 1012 8 8 6 9 5 2

»mil l f lunj . S 8 1419 6

• 3 13271712 2 10 3721 4

33112233 8 3,5 1 215 3 1 1

4 5 6 . 3 3 5 4 4 5 5 5 , 5 6 6 5 7 Avarfcjqi» P 'øre.dtamtterft iti/i.

• •

• • • •

• •

• • .

• • • 4 S 6 Aver&qe:

4.1 •62

5.9 5.3 5.3 5,1 5,5 5,1 5,0 46

49

}"

52L«.vir 4.0 4,0 42

• 1

skeler 6 r«vC lw Dirk tliij

ofTroeUan

Fig. 41. The orthogenetic change in pore-diameters of Stensioina esnehensis NAKADY and Gavelinopsis bartensteini HOFKER, in the Skrivekridt and the Fiskeler at Kjolby

Gaard and Vigso-Bjerre (See fig. 45 and p. 237).


W e find, t h a t Gavelinopsis bartensteini be low t h e K j o l b y G a a r d m a r l beg ins w i t h p o r e s a b o u t 4,0,«; a t t h e K j o l b y G a a r d m a r l t h e r e is a d i s t inc t

Fig. 42. Vigso-Bjerre

II

Skrivekridt F F Danian rtN^OfllWt*tO«l Ci O *# CO d -^ c o o o o o o o r ^ c ^ r ^ c ^ r ^ c o i > i > r * - t ^ i > a m c i o i a a o o a Gi o es os o cs

Globigerina linaperla . . X X *Glob. daubjergensis prim x x Glob, pseudobulloides .- X X Giimbelina wilcoxensis X X Chilogiimbelina X Glob. cf. triloculinoides X

Skr. F Dan. in to r- oo o o CO 00 00 00 00 Gi Ci O 05 Gi C5 CJ3

X X Glob. cf. rugosa Allomorphina cf. halli

*Boliuina basbeckensis gig.. ; X X x Cibicides bosqueti X X X X X . . X . . X . . Gavelinopsis involuta X

*Gyroidinoides subangulata X x Stiloslomella spinosa X X X X X . . X X X Dentalina cf. monile X X X x x Gauelinella pertusa maestr x x x x x x x x x x x Robulus pseudovortex X Marssonella oxycona X . . . . .'. X X X . . X X X x Gavelinopsis bembix X X X X X X

. . . . X . .

X X . . X X

X X

. . . . X

X X X X X

. . X . . X

X

X

X X X X

X X X X X . . . . X . . . . X X . . X

. . X X X X X X . . . . X . .

X

*Tritaxia danica Osangularia lens Pullenia quinqueloba Robulus rotulatus Verneuilina limbata Frondicularia biformis

*Gavelinopsis constricta Gyroidinoides pontoni Gavelinelia umbilicatiformis Alabamina dorsoplana Dentalina basiplanata Palmula robusla Globulina gibba Tritaxilina X Nodosaria vertebralis . . . . X . . X X X . . . . X . . . . Gavelinelia danica X X . . X Guttulina problema X . . . . X . . . . X Gavelinelia lorneiana x . . . . X X . .

*Bolivina hiltermanni X X X x X X X x . . X X Polymorphina frondea x . . . .

x , . . . X X

X . . . X X

X

X X X X X X . . X . . X X X . . X . . X X X X X . . X X X X X . . X X X X X X X X X . . X

X X

. . X X . .

X X

X X X

Gavelinopsis cf. incerta X *0rbignyna rimosa *0rbignyna ovata compr *Gavelinopsis bartensteini . . . . *Stensioina esnehensis *Praebulimina carseyae X X x x X X X x X *Eponides frankei X X

Gavelinopsis pseudacuta X *Gyroid. oclocamerata X X x x X X x x X

* marking species

x X x x x x x X X X X X X X X X X X X X X X X X X X X X X X X X X

. . X X X X X X X X X X X

X X X X X X . . X X . . . . X . . . . . . X

X X X X

X X X X X X X . . X X

X . . X

2 3 4 J . HOFKER : The Foramiijifera of the lower boundary of the Danish Danian

Vigso-Bjerre (contin.)

I II

Skrivekridt

X X X . . . . X

F F Danian a> o CD t ^

. . X

• * n n H r̂ r̂ r*- t^ Ci Ci OS C3

Skr. F Dan. lO tD N M Ol C CO CC 00 OC CO © CI OS Ci Ol Oi O

x

*Gauelinopsis ventricosa x X x X X Heterostomella gracilis X x . . . .

*Ataxophragmium globosum X . . . . X . . . . X . . Chrysalogonium consobrinum X Lagena sulcatiformis X Pseudoparrella alata X Cibicides cf. beaumontianus X X . . X . . Pseudoclavulina cf. anglica '. • x x . . Neoflabellina numismalis X X . . Spirillina recta X

*Bolivina selmaensis X Bolivinoides peterssoni x X Vaginulina trilobata X X . . X Gavelinonion nobilis • x - X X Enantiovaginulina recta x

*Neoflabellina poslreticulata x X . . X Cibicides compressus X . . X

*Pseudotexlularia varians x X . . . . X . . . . * Globotruncana intermedia x X * Globotruncand citae. .. X X . . Bulimina paleocenica x Bolivinoides draco X Reussella rugosa x

X X X

X X

* marking species

Fig. 43. Kjolby Gaard

<6m> 0 0 r ^ ~ H ( M C O C O l r t " » t C 0

Stilostomella spinosa x *Tritaxia danica x Frondicularia biformis x Marssonella oxycona X Gultulina problema X Osangularia lens X Gavelinopsis bembix Dentalina basiplanala Chrysalogonium consobrinum

*Karreria fallax Eponides frankei Vaginulina gladius X X Robulus pseudovorlex x X

*Gavelinopsis constricta X . . Robulus rotulatus Frondicularia X

* Verneuilina limbata Cibicides bosqueti

X X X X X X X X X X X . . X X X

X X X . . . . X . . X X X

X X . . X . . . . X X X X X X X

X X . . . . X X X X . . X . . X X X X . . . . X . . X . . X . .

. . . . X X '. . . . . X X • . X .. .. X

X . . . . X X . . . . X . . X X X X X X X . . X X X X X

X . . X X . . X

X X X

X X X . .

X . . X X X X X

* marking species

X X


Kjølby Gaard (contin.) <6m>

O O C i © w - e f ( N » n c O C ^ O O I ^ - W M C O C O m ^ f C C

Gavelinella danica X Gavelinella pertusa macstr X X X . . . . X , . X X X . . . . X . . Gavelinella cf. incerta X x X . . X Bolivinoides peterssoni X X . . . . X . . X X X Guttulina hantkeni X . . . . X Gyroidinoides subangularis x X . . X X . . . . X . . . .

*Gavelinella umbilicatiformis . . . x . . . . x x x x *Allomorphina hallijpaleoc x X . . X X Globulina gibba x Gavelinella lorneiana X X X X X Nodosaria vertebralis X X . . X X . .

*Balivina basbeckensis gig X X X Globigerina cf. triloculinoides X

*Gaudryina faujasi X X Pullenia quinqueloba X . . . . X X X . . X X . .

*Globigerina daubjergensis pr X . . *Globigerina linaperta x X *Stensioina esnehensis X . . X X X X X X X *Bolivina hiltermanni X . . X x X . . x X x *Gavelinopsis veniricosa X X X X X X *Gavelinopsis bartensteini X . . x x x x x x x *Praebulimina carseyae X . . X X X X x X X Gavelinopsis pseudacuta X . . X . . . . X Pyrulinoides acuminata X

*Orbignyna ovala compressa x . . x x x . . X X . . *Neoflabellina postreiiculata X X x . . . . X X . . *Globotruncana intermedia X X . . . . *Globotruncana citae X . . X X Globigerina biforaminata X

*Orbignyna rimosa X X . . . . . . x x x *Bolioina selmaensis X . . x Reussella rugosa X

*Gavelinonion nobilis X X . . X . . X X . . *Pseudotextularia varians X X X . . . . X X . . Cibicides compressus X

• Cilharinella. X X . . x . . *Bolivinoides gigantea X X X X Praebulimina laevis . . . . x x X . . Neoflabellina numismalis , X

*Globotruncana contusa X . . X Gyroidinoides pontoni X . . . . X Saracenaria X Enantiovaginulina recta X . . . . X X . . X Giimbelina striata X X Gyroidinoides octocamerata X . . . . X X X . .

*Spiroplectammina dentata X X X . . . . X . . Ataxophragmium globosum X x X . . X . . . . Heterostomella gracilis X Cibicides cf. beaumontianus X X

*Bolivinoides draco X . . X x . . Frondicularia sepiolaris X . . . . x . .

* Bolivinoides australis X . . . . Vaginulina trilobala X Valvulineria laevis ' X X

* marking species

2 3 6 J . H O F K E R : The Foramihifera of the lower boundary of the Danish Danian

Fig. 44. Stevns Klint

O T-"

o o <N m to rr

ir> 10 10 o o o

X X X X X X X X X X X

X X X

X X

X X X X X X X X X X

*Pseudotextularia varians , Globigerina cf. aspera' Globigerina biforaminala

*Bolivina selmaensis Nodosaria vertebralis ,

*Praebulimina carseyae Gyroidinoides subangulata Gavelinopsis bembix ,

*Orbignyna rimosa. Gavelinella incerta

*Gavelinella veniricosa Pyrulinoides accuminata , Cibicides compressus X Gumbelina striata X

*Gavelinopsis bartensleini X *Stensioina esnehensis X

Globigerina cf. linaperta X *Globigerina rugosa X

Globigerina cf. pseudobulloide\s x *Allomorphina halli x Lagena laevis Lagena sulcata ,

*Bolivina hillermanni , Eponides frankei , Marssonella oxycona Stilostomella spinosa , Guttulina problema Osangularia lens Cibicides bosqueli Gaudryina supracrelacea Chrysalogonium consobrinunt

*Bolivina basbeckensis gig X Gavelinella umbilicatiformis X

*Gavelinopsis constricta X Verneuilina limbata x Gavelinopsis involuta X Gavelinella pertusa maestr.., X Robulus pseudovorlex X

*Tritaxia danica x Pullenia quinqueloba X

*Globigerina cf. quadrata *Globigerina daubjergensis pr *Lagena sulcatiformis . . *Chilogiimbelina Globulina gibba Robulus rotulatus

*Allomorphina paleocenica *Nodosarella paleocenica Gaudryina faujasi

*Karreria fallax Gavelinella danica

*Globigerina pseudobulloides *Globigerina Iriloculinoides prfm Dentalina gracilis Palmula budensis

*Dentalina colei *Dentalina naheolensis * Dentalina pseudo-obliquestridta

* marking species.

X X X X X X X X X X

X X X

X X

X X X

X X X

X X X X X X

X X X X X X X X X

X X . X X X X X X X


Stevns Klint

frtktUr li 971

470 96« 975

978,

983

SS 990

9S6 98S

ML

KjolbyOwd

962 955 957

1 951

9SJ

9S6

965

964

963

Fig. 45. Schematic profiles of the outcrops analysed, with the samples taken.

959

rcrf

Tin

1053 1052 10*1 1056 1050

HH

1054

1055

*•*•!• Zone w i t h o u t

', ' , ' I 'Zonc w i t h

CJgg Bol . l l lAVqij .

967 •"!*» &r»v C'*>V

l l o v e F i f lc t l t r

-s.-- F£»ke l« r

• *« Flint bun c iPseudaccxtuUn

t o u t

jump in the increase, demonstrating a slight gap in sedimentation just at the base of t ha t layer (possibly due to a stream-rush). Then, at Bjerre, the continuation of the increase is found, till just below the Fiskeler, where the average diameter ends with about Q/i.

In the highest level of the sampling a t Basbeck and Hemmoor, Gaveli-nopsis bartensteini shows average pore-diameters 3/i; so it will be obvious tha t the lowest studied Pseudotextularia-zone forms a stratigraphically higher level than the highest Basbeck samples.

In the dark lower layer of marl of the Fiskeler, we find diameters which correspond more or less with those of the highest level of the underlying Pseudotextularia-zone; this indicates tha t the Fiskeler-sea only grazed the uppermost surface of the Skrivekridt and did not, when returning, abrase the slightly hardened bottom. But in the layer of grey clay above, suddenly we find only those specimens of Gavelinopsis bartensteini, which also are found at the base of the Kjolby Gaard quarry, thus demonstrating, tha t after the return of the sea, it then transgressed over its former borders, abrasing the rocks of Skrivekridt.

Quite a similar history can be read from the pores of Stensioina esne-hensis, bu t for a slight increase of diameters a t the Kjolby Gaard marl. Bu t the Fiskeler shows identical pore-aberration.

In Belgium, in the large quarry a t Hallembaye, Gavelinopsis bartensteini

2 3 8 J. HOFKER: The Foraminifera of the lower boundary of the Danish Danian

[ t - c O ! ° *

* * • •*- *i ^ G

Zone wi th m».ny new formt

Z o n e w l k h out l iv ing Cret&teeus forms

Flskcler w i t h reworked forrns

Zone often w i thout - southern forms Stevns KUnt u n a

BtlivinoCd.es f i a A n t e i .

Psaudotax-tutxr ia . l o n e

dolivinoides a.ustra.Us

Ba-rieck zone. (Svenstrup z-one.)

/Aoens Klint zona

Fig. 46. Zones of Upper Maestrichtian and Lower Danian with identical Foramini-feral faunae and identical orthogenetic stages in Holland and in Denmark. The chalks of Svenstrup and Moen, not mentioned in this paper, represent the faunae as found

in Dutch Cr3c and Cr3b.

in the highest samples has an average pore-diameter of 4-4,5/*; but a t the top of tha t quarry, the Cr4 just begins; in samples taken above the hard ground a t Orp-le Pet i t in Belgium, with a fauna indicating the age of the Cr4, Stensioina esnehensis shows the average of porediameters of 5/i, and Gavelinopsis bartensteini also shows pores of 5-5,5/* diameter. Thus both data strongly indicate tha t the Cr4 (Craie tuffoide) of Belgium is of the same age as the Pseudotextularia-zone in Denmark. In Southern Belgium (Basin of Mons) in the conglomerate forming the base of the Tuffeau de Saint Symphorien, Bolivinoides gigantea, Stensioina esnehensis and Gavelinopsis bartensteini show exactly the same stages as found in the highest Pseudotextularia-zone in Denmark. This conglomerate thus is of tha t time, and the Tuffeau de Saint Symphorien—always parallelised with the Maestrichtian Chalk Tuff of Holland—must be younger than the top of the Pseudotextularia-zone in Denmark. In Holland, Stensioina esnehensis was not found, but Gavelinopsis bartensteini here shows during the Cr4 pore-diameters from 5,5 to 6(i, just the stage of development found also in the higher par t of the Pseudotextularia-zone. Since these ortho-geneses of pores, now established for many species and many localities, have been proved to be very reliable, there cannot be any doubt as to the parallelisation of the Cr4 in Holland, the Craie tuffoide in Belgium and

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the Pseudotextularia-zone in Denmark. They not only show a striking resemblance in their faunae, but also in the stages of development of the pore-diameters of Stensioina esnehensis and Gavelinopsis bartensteini, and moreover, in the last stages of Bolivinoides gigantea and Neoflabellina postreticulata.

That the gap between the upper Skrivekridt and the lowest Danian in case tha t a Fiskeler is present between them, is very small and equally small as the gap in Holland at the Ma, was shown by the author by means of the pore-orthogenesis of Gavelinopsis involuta ( R E U S S ) (Natuur-hist. Maandblad, 48, 1959, p . 51) and is reproduced in fig. 47. It shows tha t during the whole Tuff Chalk of Maestricht and the whole Danian the pore-diameter increases from about 3,4 (3,6) to 6,o (6,i); but from uppermost Cr4 (Skrivekridt) to lowest Tuff Chalk (Danian) it passes from 2,9 (2,6) to 3,4 (3,e); this indicates tha t the gap in both localities was but a fraction of the duration of the formations of Tuff Chalk and Danian.

Diagram, showing the orthogenesis of Gavelinopsis involuta ( R e u s s ) in the type-Danian and the type Maestrichtian.

(diameters in .u)

D A N I A N of D E N M A R K Averages

Hyttehusvej Hvallose 1 Faxe 3 8 Kagstrup 1 4 35 Stevns Klint l 13 36 Erslev Andeisbrud 2 9 12 7 Pseudotext. Stevns Klint 2 7 13 5

Pore-diameters Zones

10 14 10 3

1 15 4

M A E S T R I C H T I A N h. gr. Md-Me, Can. Alb. D12 Canal Albert h. gr. Mc/Md Curfs Q. de Tombe 147—148 1 Cl/4 Canal Albert 6 B24 Canal Albert 1 1 6 B14 Canal Albert 1 6 5 B8 Canal Albert 3 5 5 1 A10 Canal Albert 6 8 7 Glons 126 m + N.P. 4 18 19 3

2 2,5 3 3,5 4

5 5

2

4,5

5 2 3 12 3

5

5 20 5 1 Zone I 15 24 7 Zone II

Zone III Zone IV Zone V Zone VI

Pseudotextularia-Zom

CHALK T U F F . 4 21 11 6 1 1 Me 3 3 Md/Me 7 9 3 Md 10 2 Mc

Mc Mc Mb Mb Cr 4 Cr 4

5,5 6 6,5 7 74 8

6,0 5,2 4,3 4,0 3,9 3,4

: 2,9

6,1 5.7 5,8 5,1 4,4 3,9 3,6 3,2 3,6 2,6

2 3 4 5 6

Fig. 47. Orthogenesis of pore-diameters ol Gavelinopsis involuta ( R E U S S 1862) in the Cr4-Chalk Tuff of Maestricht and in the upper Skrivekridt-Danian; from HOFKER, The Danian age of the Maestrichtian Chalk Tuff proved by the orthogenesis of Gavelinopsis involuta ( R E U S S ) ; Natuurhist. Maandblad, 48, 1959 pp. 51-53. (The

"zones" in the Danian are not those of W I N D ) .

The Fiskeler Since this layer only contains the smaller forms of the species of the

underlying Pseudotextularia-zone, bu t does not contain, neither in the Thisted region, nor in Stevns Klint, any planctonic forms but for specimens of Globigerina rugosa, one may conclude, tha t in Stevns Klint the dried-out uppermost non-planctonic zone of the Pseudotextularia-zone was eroded before the Danian sea returned (just below the Fiskeler we find a rich planctonic fauna), or t ha t there was made, during the transgression, a selection in the material, the lightest forms being washed away. Measures of pores in some of the Gavelinellidae from the Fiskeler reveal

240 J. HOFKER: The Foraminifera of the lower boundary of the Danish Danlan

data, already given above: the typical Fiskeler itself shows the pore-diameters of the uppermost Skrivekridt, and thus contains only those specimens which were killed at the time of the disaster which ended so abruptly the sedimentation of the Skrivekridt; the upper zone of the Fiskeler, the greyish marl between it and the real Danian, contain tests of both species analysed from levels below the Kjolby Gaard marl of the Skrivekridt; so after the return of the sea, this return has been continued by a transgression. Yet the whole Fiskeler-time was a very short one. So, the Fiskeler may have been due either to a short heating up of the whole earth (evaporation of the water) or to a short glacial period; both phenomena will have caused equal phenomena in the sedimentation. The occurrence of many loosened, not eroded or ground fragments of Skrivekridt in the Fiskeler, would point to a freezing-up of the dry surface of the Skrivekridt.

The lowest Danian In this zone there are some typical markers, as already stated. Tritaxia danica nov. spec. (Fig. 23). Triangular par t distinct, bu t with

rounded angles; outgrown specimens develop a relatively long triangular par t with parallel sides, ending with the terminal chamber with terminal elongate aperture on a somewhat conical neck. The species is quite distinct from Tritaxia jarvisi CUSHMAN from the Lizard Springs Formation in Trinidad; the latter form seems to be the end form of Verneuilina limbata and does not show the parallel sides; moreover in T. jarvisi the sutures, though flush with the surface, always are quite distinct; in Tritaxia danica on the other hand the sutures are nearly invisible, and, moreover, the angles over the whole test are rounded. Since, however, there are indications of a uniserial arrangement of the last formed chambers, maybe the species forms the transitional stage to Clavulinoides trilatera (CUSHMAN).

Karreria fallax. This species, just as in Holland, begins its development after the Fiskeler; i t is a thin walled species, and in the lower Danian there are only types with a sutural aperture ( H O F K E R , J. , On Karreria fallax R Z E H A K ; Natuurhist . Maandblad, 46, 1957, pp. 98-100).

Gavelinopsis cf. constricta R E U S S (Fig. 17). In the lower par t of the Danian in Kjolby Gaard, Bjerre and Stevns Klint a typical species appears which is, with some doubt, at tr ibuted to "Cibicides" constrictus R E U S S ; it shows many chambers in the last formed whorl, at the ventral side around a very distinct central plug, at the dorsal side with slightly compressed sutures not reaching the centre, slightly rounded margin, and thus somewhat alike Gavelinopsis complanata bu t with more chambers in a whorl; all specimens observed are, a t least near the centre of both sides, brownish in colour. I t is not the species which as such has been mentioned by. BROTZEN (Flintrannans och Trindelrannans Geologi; Sver. geol. Unders., C, 453, 1940, p . 26-28) for this species does not occur in the upper Senonian, and it seems to be absent in the upper Danian. Obviously BROTZEN means with his Cibicides constrictus R E U S S the


species which R E U S S himself in 1862 found in the Maestrichtian Chalk Tuff as the most common Foraminifer, and called then Cibicides involute R E U S S . SO I have in all cases in which it was certain tha t t ha t species was found (Maestrichtian Chalk Tuff, Danian of Denmark and Sweden) called it Gavelinopsis involuta ( R E U S S ) (HOFKER,- J. , Natuurhist . Maand-blad, 48, 1959, pp. 51-53). But the species here shows much more chambers in a whorl and moreover never shows pores in the dorsal chamber walls, which character is typical for Gavelinopsis involuta ( R E U S S ) . "Cibicides" constrictus R E U S S shows quite the typical features of the species found only in the lowest Danian. In the Senonian two other species, much resembling the species here as well as Gavelinopsis involuta, occur, viz. Gavelinopsis complanata ( R E U S S ) and Gavelinopsis barlensteini H O F K E R . These two species have been fully analysed by the author (Foraminiferen von Nordwestdeutschland und Holland, Geol. Jahrbuch, Beih. 27, 1957, pp. 324-330). Since each of these species shows a specific orthogenesis of pore-diameter development (increase) they cannot form a single species, running from Campanian up to upper Danian, as BROTZEN believed in 1940.

Verneuillina limbata CUSHMAN is very common in the Danian bu t rather rare in the Upper Senonian; yet it is a species which seems to begin in the Lower Maestrichtian and runs through the Fiskeler up to the Upper Danian. I t is characterised by the very sharp angles, the somewhat compressed flat sides, and the tapering triangular shape.

Allomorphina halli JENNINGS (Fig. 12) already begins in the Upper Maestrichtian, but is rare in the Danish Pseudotextularia-zone. I t is common in the Danian itself and is also found in the lower Paleocene. In the Danian it is accompanied by another species, A. paleocenica.

Bolivina basbeckensis H O F K E R gigantea nov. subsp. (Fig. 16). In the upper Campanian and lower Maestrichtian Bolivina incrassata R E U S S is a common form; in the Lower Maestrichtian itself it develops three generations and then becomes very large and stout (Bolivina incrassata gigantea W I C H E R ) ; the development of this species, with flush sutures, has been fully analysed b y the author (1. c. Nordwestdeutschland, pp. 235-247); the species extinguishes with these very stout forms. At the end of this development a new species (mutant) is formed, in which the sutures are distinctly compressed and in which once again the trimorphic stage is reduced to a dimorphic propagation. I t begins a t the beginning of the Upper Maestrichtian, and has been called by the author Bolivina basbeckensis (1. c , p . 233). This species also is found, in relatively small specimens, in the Pseudotextularia-zone, however, here it is never common. Bu t in the metre of sediment above the Fiskeler this typical species suddenly forms the commonest form in the fauna, a Danian fauna; moreover, the specimens once again are very stout, much stouter than the specimens in the Pseudotextularia-zone. Here the species once again is distinctly trimorphic. So, this remarkable subspecies not only transgresses the Fiskeler phenomenon, but shows after the Fiskeler a similar last flaring up as its ancestor, B. incrassata did formerly. Suddenly, a t the end of this formation above the Fiskeler, it vanishes totally, which is seen on

242 J. HOFKER: The Foraminifera of the lower boundary of the Danish Danian

the range-charts of Kjolby Gaard and Stevns Klint. I t thus forms an extremely good guide-fossil for this lowest zone of the Danian.

Globigerina linaperta Finlay (Fig. 26, 28). A very small species, very similar to Glob, daubjergensis, bu t totally missing the openings at the dorsal sutures, characteristic for the latter, is found in the lowest Danian. I t is the only species found, together with some, possibly reworked, small specimens of Globigerina rugosa PLUMMER (Fig. 24). Such specimens as G. linaperta also are found in the lower Maestrichtian Chalk Tuff. I t may also be, tha t all these specimens already belong to the first stages of G. daubjergensis; they have been mentioned in the range chart as daubjergensis primitiva (see Fig. 25). A very typical Globigerina is found, often abundantly; it resembles G. quadrata W H I T E , but also it may

. be the most primitive stage of G. pseudobulloides; it shows its characters, but the aperture never has the typical lip. It has been mentioned as G. quadrata in the range charts (Fig. 31). However, it may form a different species. Such forms also have been detected in the uppermost Cr4 a t the contact with the Ma, in Holland (Glob, pseudobulloides, see H O F K E R , Natuurhist . Maandblad, 45, 1956, p. 55, fig. 4).

The second zone of the Danian Above the lowest metre of Danian, suddenly the whole fauna changes;

this can be clearly seen in the samples from Kjolby Gaard and from Stevns Klint. Bolivinoides basbeckensis gigantea disappears, and the planctonic fauna also changes abruptly; typical G. pseudobulloides and G. daubjergensis appear. At Stevns Klint this zone is a bryozoic limestone, at Kjolby Gaard it forms a tuffoid chalk, with nearly no Bryozoa.

Allomorphina paleocenica CUSHMAN (Fig. 30). This species is characterized by the triangular and high last formed chamber; transitional stages with A. halli are found. In the Maestrichtian Chalk Tuff halli is common in the Mb, A. paleocenica in the Mc and Ma. In the Danian also halli is found in the lowest level, paleocenica in the second one; bu t higher up once again halli is found; this also occurs in the highest level of the Maestrichtian Chalk Tuff, where halli reappears in the Me and the lowest Paleocene, just as in Denmark. A. paleocenica seems to be restricted to a slightly higher temperature. The second zone is more characterised by the absence of Bolivina basbeckensis gigantea than by new forms. In both localities studied, this zone shows a poor fauna of bentonic species. The author described some of these forms (Natuurhist. Maandblad, 44, 1955, pp. 103, 106); the species A. paleocenica was referred to in this paper as A. cretacea CUSHMAN; but in the Danian as well as in the higher Maestrichtian Chalk Tuff the specimens already get the features of A. paleocenica.

All species of Foraminifera mentioned in this paper have been stored in the collections of the Geological Survey, Haarlem, Holland.

the foraminifera of the lower boundary of the danish...

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