Geological Survey of Finland

Bulletin 352

New cores from Eemian interglacial deposits in Ostrobothnia, Finland

by Tuulikki Grönlund

Geologian tutkimuskeskus Espoo 1991 Geological Survey of Finland, Bulletin 352

NEW CORES FROM EEMIAN INTERGLACIAL DEPOSITS IN OSTROBOTHNIA, FINLAND

by

TUULIKKI GRÖNLUND

with 10 figures in the text and 2 plates and 2 appendices

GEOLOGIAN TUTKIMUSKESKUS ESPOO 1991 Vammala 1991 , Vammalan Kirjapaino Oy Grönlund, Tuulikki 1991. New co res from Eemian interglacial deposits in Ostroboth­ nia, Finland. Geological Survey oj Finland, Bulletin 352, 23 pages, 10 figures, 2 plates and 2 appendices.

Till-covered sediments containing marine diatoms have been found at Norinky­ lä (Teuva) and Ukonkangas (Kärsämäki) in Ostrobothnia, western Finland. The different types of diatom stratigraphy at these sites are described, and the sites are correlated with the Eemian interglacial stage. At Norinkylä, Eemian marine deposits are underlain by freshwater deposits whose diatom flora contains the same taxa as the Holocene Ancylus Lake. The deposits of the Eemian Baltic Sea proper at Ukonkangas and Norinkylä have a rich marine diatom flora with the same taxa as encountered earlier in Eemian deposits in Ostrobothnia. The phases of the Eemian Baltic Sea are discussed.

Key words: stratigraphy, diatoms, interglacial environment, marine environment, freshwater environment, sediments, Eemian, Baltic Sea, Ostrobothnia, Finland.

Tuulikki Gränlund, Geological Survey oj Finland, SF-02150 Espoo, Finland

ISBN 951-690-417-3 ISSN 0367-522-X CONTENTS

Introduction ...... 5 Sampling and methods ...... 6 The Norinkylä site at Teuva ...... 6 Core A ...... 7 Core B 10 Core C 13 Core D 13 Open section of the Haapalankangas esker at Jurva ...... 15 The Ukonkangas site at Kärsämäki ...... 15 Discussion ...... 17 Conclusion ...... 19 Acknowledgements ...... 22 References ...... 22 Plates Appendices INTRODUCTION

In recent years, sediments containing diatoms land. Many of these sediments can be interpreted have been found underlying glacial till at several as having deposited in the Baltic Sea basin dur­ sites, particularly in Ostrobothnia, western Fin- ing the last, i .e., the Eemian, interglacial stage.

FINLAND SWEDEN USSR

,~ .ROVA I 64° r- 64° ~'& )~~ . OLLALA f / 0" • UKONKANGAS ~Qj ;: Q:) 0 0 ~ ~ • EVIJÄRVI 0V ( " • HIETAKANGAS ":> .VIITALA o : HAAPALANKANGAS ~ ! NORINKYLÄ OnegO :

BOLLNÄS • ,I Bothnian Sea . SOMERO 0 HELSINKI F·n1and .MGA 11 ) PRANGLI NYKOPING ~f' ESTONIA 11 Baltic Sea ( 250 h- I 300 km

Fig. I. A) A map showing lhe main localilies of Eemian marine dialOm bearing sedi· ments in Fennoscandia and lhe nonh-weslern Soviel Union and lhe siles menlioned in lhe lext. B) A localion map of Fennoscandia, lhe nonh-weslern Soviel Union and the Ballic Sea. Ostrobolhnia is indicaled by shading. 6 Geological Survey of Finland. Bulletin 352

The correlation is based on lithm,tratigraphy and or mixed with freshwater diatom flora in several pollen stratigraphy. The main Eemian marine places in Finland, Sweden and Soviet Karelia sites in Finland studied by means of diatoms are (e .g. Halden 1915, Brander 1937 a, b, 1943, Tyn­ Evijärvi (Eriksson et a/. 1980), Ollala (Haapavesi) ni 1971, Miller & Persson 1973, Niemelä & Tyn­ (Forsström et a/. 1987, 1988 and Grönlund 1988) ni 1979, Grönlund et a/. 1985, Passe et a/. 1988, and Viitala (Peräseinäjoki) (Nenonen el a/. in Garcia Ambrosiani 1990). press). The location of the sites i5, shown in Figure New coring was undertaken at Norinkylä (Teu­ I. The Eemian Baltic Sea diatom flora of Suur­ va), the si te already studied by Niemelä and Tyn­ Prangli, nowadays Prangli (see Liivrand in ni (1979) and Donner (1988). Sampies were also press), an island off the coast of northern Esto­ taken from a silt deposit underlying till at nia, has also been presented, first by Chere­ Ukonkangas (Kärsämäki) and Haapalankangas misinova (I961) and later by Lii vrand (1984, (Jurva) (Fig.l). The diatom stratigraphy of these 1987, in press) on the basis of the diatom studies sites is presented in order to provide new infor­ of Cheremisinova (Fig. I). Eemian marine mation about the Eemian Baltic Sea, its north­ deposits and diatoms are also found redeposited ern and northeastern parts in particular.

SAMPLING AND METHODS

At Norinkylä the sam pies were taken using a sampie depth. percussion drill with a flow-through bit sampier . The diatoms were c1assified according to At Ukonkangas and Haapalankangas they were salinity preference as polyhalobous (salinity in the taken by spade from an exposed section. habitat 35-17 parts per mille), mesohalobous in­ The sam pies were first bleached with diluted c1uding meso- and pleioeyryhaline polyhalobous

H 20 2 for 24 h at 50°C, and then subjected to (salinity in the habitat 35-3 parts per mille) and repeated suspensions and decantations. The oligohalobous, which are freshwater species. The mounting medium was Hyrax Liquid with a c1assification is that of Simonsen {I 962) as refractive index of 1.65. Whenever possible, at applied to Finnish conditions by Tynni (Nieme­ least 500 diatom valves were iclentified from each lä & Tynni 1979).

THE NORINKYLÄ SITE AT TEUVA

The Norinkylä site lies in the municipality of 110 m above sea level because a 2-3 m thick till Teuva (62°35 ' 45' 'N and 22 "01' 07' 'E) (Fig. 1). bed had been removed from the surface. A dis­ The sequence occurs in a narrow till-covered turbed c1ay layer, about 12 cm thick, was in­ esker trending north to south, and bounded on c1uded in the section studied by Niemelä and Tyn­ its western side by Rahkaneva mire. ni (1979). This c1ay contained a marine diatom The Norinkylä site was first studied by Niemelä flora with species commonly found in marine and Tynni (J 979). The section they studied was Eemian deposits. According to Niemelä and Tyn­ on the western slope of the esker, with its crest ni, the c1ay had deposited c10se to the shore dur­ at 112 m above sea level. When Donner (I988) ing the Eemian marine stage. This marine Eemian later studied the same site, the crest was at c1ay was not encountered in the section studied Geological Survey of Finland, Bulletin 352 7

SE ~ --,--,_ _ -----:---'110m o s l '"I" " r;....~ " " I'.

/'; "

" "

C PEAT I'. " ~~: " w TILL ~ IT'MB FINE WATE RLAIN SED IMENTS I SILT. GYTTJA SI LT. SAN D I

------, 50 100 150m Fig. 2. COTes from the Norinkylä (Teuva) site. Co res A, B, C and D were sludied.

by Donner (1988). Besides the clay layer, there 30 cm of clay, the lower part of which is mixed was a lens of gyttja (organic mud) with marine with the till deposit (Fig. 3 and Appendices 1-2). diatoms in its upper part, although the rest of the The uppermost part of the silt layer was probably gyttja was regarded as a freshwater deposit. This cut away when the overlying till deposited or then gyttja had later been mixed with probably re~ it was missed in sampling. worked sediments containing Eemian diatoms The succession of the diatom taxa is given in (Niemelä & Tynni 1979). Appendix 1 (polyhalobous and mesohalobous New sampies for diatom analysis were col~ species) and Appendix 2 (freshwater species). The lected from the Rahkaneva mire in 1987 and diatoms, classified according to their salinity and 1989. The sam pie site lies northwest of the sec~ temperature demands (cold or warm water con~ tion studied by Niemelä and Tynni (1979) and ditions) mainly after Hustedt (1930), Cleve-Euler Donner (1988), in the direction from which the (1940), Miller (J964) and Guillard and Kilham glacier approached. Eighteen attempts to drill (1977), are presented in Figure 3. Environmen­ good cores through very hard till deposits with tal changes shown by dia tom stratigraphy are also big boulders (cL Fig. 2) produced only four satis­ shown. The lowermost sampie of the core, from factory cores (A-D). Their distances from the a depth of 12.75 m, contains a small number of section studied by Niemelä and Tynni and Don­ diatoms (Fig. 3). The main species are the meso­ ner were as folIows: core A 120 m, core B 130 halobous Grammatophora oceanica Grunow and m, co re C 140 m and core D 175 m (Fig. 2) . Rah­ Hyalodiscus scoticus (Kützing) Grunow, both kaneva mire is at 110 m a.s.l. The thickness of earlier interpreted as typical of the Eemian Bal~ the peat layer overlying the till deposits is 0- tic Sea. Aulacoseira lirala (Ehrenberg) Ross 3 m at the sites of the cores studied. (Aulacoseira = Melosira, see Simonsen 1979 and e.g. Hartley 1986), which is a freshwater species, is also common. Otherwise the clay layer in the Core A bottom of the co re contains diatoms characteris­ The core, almost 4 m long, consists of organic tic of freshwater conditions, with Aulacoseira silt covered by till. The silt is underlain by about lirata, A. islandica (0. Müller) Simonsen and A. 8 Geological Survey of Finland, Bulletin 352

Core A. NOTri_n_kr-y_llI____ _

DIATOMS

[[] POLYHALOBOUS

V1 >­ V1 I IrCl. '3 <{ MESOHALOBOUS a: c:J z !2 9 I t:: ~ >­ a: Cl. OLiGOHALOBOUS ;; z >­ W Jillli~ z !2 V1 o w

560 520 E 500 500 E 550 550 M 510 I 52051.0 A 550 N 500 500 S E 550 \ A 51.0 500

( ·580 500 550 ) 510 \ 630 I 520 515 , 500 550 1 515 -1 \ 560 500 '2 500 500 ------j== -===t ( 55 107 "RESH

300 WAT ER [-= . 150 .., .~

.., ~ "----'------'--~ L-_ % 10 % 10 20 30 1. 0 50 60 70 80 90 100 o 10

=-~ ~CLAY . GYT JA S L'

Fig. 3. Diatom groups by salinity, temperature dema nd (lhermophilous and cryophilous species) a nd changes in sedimentary environment (lake/ sea) according 10 the diatom spectra in co re A, Norinkylä. Geological Survey of Finland, Bulletin 352 9 islandica subsp. he/vetica (0. Müller) Simonsen 1937a, b). (often as resting spores), A . ita/ica (Ehrenberg) The most characteristic mesohalobous species Simonsen, Cyclotella kützingiana Thwaites and are Actinocyclus octonarius Ehrenberg (syn. A. species of the genus Pinnu/aria dominating. ehrenbergii Ralfs), Cocconeis peltoides Hustedt, At a depth of 12.15 m the diatom flora C. scutellum Ehrenberg, Navicu/a digitoradiata changes, and Aulacoseira species are almost (Gregory) A. Schmidt, N. peregrina (Ehren berg) totally lacking from the rest of the core. The Kützing, Nitzschia sigma (Kützing) W. Smith, diatom flora in the sediments above a depth of P/eurosigma angu/atum (Quekett) W. Smith, 12.15 m is rich and very homogeneous. The Rhopa/odia gibberula (Ehrenberg) O. Müller and dominant mesohalobous species account for Synedra tabu/ata (Agardh) Kützing. about 60-80 070, polyhalobous species for about Many Dip/oneis species, e.g. D. mediterranea 20 070 and freshwater species for 1-23 070 (Fig. 3). (Grunow) eleve, D. notabilis (Greville) eleve, D. The mesohalobous species Grammatophora papula (A. Schmidt) eleve, D. subcincta (A. oceanica, G. oceanica var. maci/enta (W. Smith) Schmidt) eleve, D. suborbicularis (Gregory) Grunow, Hya/odiscus scoticus, Rhabdonema eleve and D. vacillans (A. Schmidt) eleve, which arcuatum (Lyngbye) Kützing and Me/osira su/­ were also encountered in the Eemian sediments cata (Ehrenberg) Kützing dominate, as they do at Evijärvi and Ollala, are common. Dip/oneis at the sites studied by Niemelä and Tynni (1979), chersonensis (Grunow) eleve and D. crabro and at Evijärvi, Ollala and Viitala. Ehrenberg, which favour high salinity, were also Other species typical of the diatom flora of the found in this core. Many of the above Dip/oneis Eemian Baltic Sea include AClinocyclus kützin• species indicate warm water conditions and thus gii (A. Schmidt) Simonsen, Actinoptychus lend support to the concept of an oceanic con­ senarius Ehrenberg, Auliscus scu/ptus (W. Smith) nection in the west (cf. Zans 1936, Niemelä & Ralfs, Campy/odiscus jastuosus Ehrenberg, Tynni 1979). As weil as the thermophilous spe­ Dimeregramma (Dimerogramma) minor (Gre­ eies, some cold or Arctic water species such as gory) Ralfs, Navicu/a abrupta (Gregory), Campy/odiscus angu/aris Gregory, Gram­ Grunow. N. /yroides Hendey, Stephanopyxis matophora arcuata Ehrenberg, Navicula g/acia­ turris (Greville) Ralfs, Tha/assionema nitz­ lis (eleve) Grunow, Rhizoso/enia hebetata for. schiodes Grunow, Tha/assiosira eccentrica hiemalis Gran and Trachyneis aspera (Ehren berg) (Ehrenberg) eleve and T. gravida eleve, all of eleve imply access to the White Sea (cf. Nieme­ which are polyhalobous. Podosira hormoides lä & T ynni 1979, Grönlund 1988). According to (Montagne) Kützing and P. montagnei Kützing, eleve-Euler (1940), Pinnu/aria crucijormis which were not found at Evijärvi, Ollala or Viita­ (Don kin) eleve and P. treve/yana (Don kin) la, are quite common in this core. P. montagnei Rabenhorst also thrive in cold water. The fre­ favours waters of lowered salinity, too, and is quency of the diatoms indicating warm or cold common in the Baltic Sea and on all North Sea water is similar throughout the core (cf. Fig. 3). coasts (Hustedt 1930, Hendey 1964), but no The lagoonal ~pecies Amphora robusta observations have been reported from the Finn­ Gregory, Campy/odiscus clypeus Ehrenberg and is h coast (Mölder & Tynni 1967) . The species is Nitzschia sca/aris (Ehren berg) W. Smith were also common on all European coasts. as is P. encountered throughout the profile, although in hormoides (Hustedt 1930). Several P. montag­ lower abundances. nei specimens have been fo und in the silt layers Some silicoflagellates, which are marine plank­ of Hietakangas and Rova, in the clay of Norinky­ ton algae, have also been encountered. In the lä esker (Niemelä & T ynni 1989) and in deposits Rouhiala clay in the Karelian Isthmus (Brander at Rouhiala (Brander 1937a) and \1ga (Brander 1937a) and in the Eemian deposits studied earlier 10 Geological Survey of Finland, Bulletin 352 in Ostrobothnia (e.g. Niemelä & Tynni 1979, terrestrial habitats, e.g. Hantzschia amphioxys Eriksson et al. 1980, Grönlund 1988) they are (Ehrenberg) Grunow, Pinnularia borealis (Ehren­ quite common. Distephanus speculum (Ehren­ berg) and Aulacoseira epidendron (Ehrenberg) berg) Haeckel, commonly believed to be a cold­ Crawford, are also fairly common. These fresh­ water form, was most common in this core, and water diatoms are very different from those was found throughout its whole length in clusters found in the clay layer underlain by silt. of 1-8 specimens in alm ost every sarnple stud­ As shown by the diatoms, the clay in the lower ied. Although rare, Distephanus speculum var. part of the co re was deposited in freshwater. The septenarius (Ehren berg) Joergensen was also lowermost sampie (at a depth of 12.75 m) was found . Dictyocha fibula Ehrenberg, which is be­ probably contaminated in the course of sampling, lieved to favour warm water, was noted but it is and the Eemian species derive from the overly­ not so common as D. speculum (1-3 specimens ing deposits. The bulk of the core deposited in in some sampies). The ratios of the silicoflagel­ the littoral part of the Eemian Baltic Sea, which lates Dictyocha to Distephanus have been used is characterized by the rich diatom flora inter­ to determine cold and warm periods in the recent preted as typical of it. geological record. Schrader and Richert (1974) report that the percentage of Distephanus in­ creases exponentially as the surface sea tempera­ Co re B ture falls from 16.5 °C to 8°C, whilst the per­ centage of Dictyocha increases within the range Owing to the difficulty of sampling, core B is 19.5°C-25°C. Niemelä and Tynni (1979) discuss discontinuous (Fig. 4). It is composed of silt and and present Dictyocha/ Distephanus ratios which gyttja silt. The diatom flora in the basal part (at are used to determine the palaeotemperatures of a depth of 9-10 m) is similar to that in the oceanic waters (cf. Gibbard et al. 1989). The silt of core A. Grammatophora oceanica, G. abundance of silicoflagellates in core A is so low oceanica var. macilenta, Hyalodiscus scoticus, that there is no reason to apply the ratio here. Melosira sulcata and Rhabdonema arcuatum are According to Round (1981), Distephanus has a the dominant species, although other diatoms higher dissolution rate than Dictyocha and there­ characteristic of the Eemian BaItic Sea also oc­ fore the fossil assemblages do not neces.sarily give cur. The silicoflagellates Distephanus speculum an accurate picture of the palaeoenvironment. and Dictyocha fibula and also Actiniscus pen­ Furthermore, Sancetta (1990) has recentiy shown tasterias are all present. that forms of silicoflagellates do not have a The species change at a depth of 8 m, and the simple and consistent relationship to the tempera­ lagoonal species Campylodiscus cfypeus and ture of the overlying water column. Nitzschia scalaris predominate (Fig. 4) . These Ebria tripartita (Schumann) Lemmermann, species are classified among the Clypeus flora, which belongs to the order Ebriales, was also which were typical of the Holocene Litorina Sea found, although rarely. In contrast, occurrences of the Baltic Sea, indicating the lagoonal phase of the dinoflagellate species Actiniscus pen­ slightly before the basin was isolated from the tasterias Ehrenberg are common. sea (in detail cf. Grönlund in press). Above a depth of 12.15 m, freshwater species A corresponding Clypeus flora was earlier of interest in the core are Cymbella cuspidata encountered in an Eemian deposit at the Evijär• Kützing, C. turgida Gregory, Stauroneis vi site in a silt layer interpreted as having accumu­ phoenicenteron (Nitzsch) Ehrenberg, S. javanica lated in a shallow bay of the Eemian Baltic Sea (Grunow) Cleve and genera of Eunotia and Pin­ (Eriksson et al. 1980). At Evijärvi, the Clypeus nularia. The aerophilic species found in modern flora accounts for less than 5 070 of the species Geological Survey of Finland, Bulletin 352 11

Core B, Norinkylä

>- I Q. D POLYHALOBOUS e:( a:: (!) E I 1::::::::::::::::::1 MESOHALOBOUS ~ t- a:: Q. t- UJ (/) 0 I::::::::::::::l OLiGOHALOBOUS

6. 6. 6. 12

6

520 520 510 374 50 5

12 14

150 5 516 510 500 500 ) 510

NO SAMPLES

225 480 550

510 500 500 530 520 I

% 10 20 30 40 50 80 70 80 90 10 20 30 40 50 60 70 80 10 10

W TILL Ld SILT ~ GVTIJA SILT D SAND

Fig . 4. The diatom groups by salinity and lagoonal species in co re B, Norinkylä.

and is thus not as abundant as in core B at deposit containing the Clypeus flora at Norinkylä Norinkylä. is distinctly interglacial: Corylus pollen account According t.o the pollen composition, the for about 20 070 of total arboreal pollen (Brita 12 Geological Survey of Finland, Bullelin 352

Core C. Norinkylä

OTHER ALGAE

(j) 110m OIATOMS a:: --.J W ...... , ...... f- ...... =:> (j) . .····]·· ...... u ...... Q f- (]J (j)(j) Z (j) >- W f- (j) I LL (j)a:: Q a:: a:: I - WW Z u ~ IJ) 0 2:0 Ci o ..

[:, [:,

[:,

[:, [:,

8 9 9 5 8 3 [. [.

POOR IN OIATOMS

7 5

10 11 > ~ 5

( 7 ~ 8 7 '3 .- ~ ~·_· I POOR IN DIATOMS II 120-> .~ 6. --~~.~~ % 10 0/0 10 20 30 {.O 50 60 70 80 90 .0 ::0 '05

ry' · 0 %0

Fig. 5. The dialOm groups by salinilY ~nd invesligaled silicotlagdlale, JnJ other dlgae (,akulated from lOtal dialOms) in co re C, Norinkylä. Sediment symbols as in Figure 3. Geological Survey of Finland, Bulletin 352 13

Eriksson, oral communication). Moreover, at 110 sively of polyhalobous and mesohalobous taxa. m a.s.l., the Norinkylä site is above the highest Surprisingly enough, at a depth of 10.10 m, the local Holocer..e Litorina Sea shore at about 90 m sam pie contains 32 070 freshwater species but the a.s.l. (Hyyppä 1966, Eronen 1974). Therefore, number of species is very low. Pinnularia lata the Clypeus flora cannot be attributed to con­ (Bn.'bisson) W. Smith predominates (24 070), the tamination of the sampie. others being Melosira arenaria, Eunotia praerup­ Freshwater diatoms increase markedly in the ta Ehrenberg, Tetracyclus lacustris var. capila upper part of the core, accounting for over Hustedt, Aulacoseira islandica and fragments of 90070 of the species. Cymbella aspera (Ehrenberg) Pinnularia species. Most of these are oligotrophie Peragallo, C. cistula (Ehren berg) Kirchner, C. lake species and probably derive from the upper cuspidata, C. tumida (Bn:!bisson) Grunow and C. horizons as a result of contamination in the turgida as weil as the genera Eunotia and Pin­ course of sampling. nularia predominate. The upper part of core B deposited in shallow lagoonal water of the Eemian Baltic Sea. Even­ Core D tually the basin was already isolated from the ma­ rine water body. The profile is composed of silt and gyttja silt (Fig. 6). In its diatom assemblage the lower part of the profile resembles that of profile C. In the Core C lowermost sampies (at a depth of 11 .85- 11 .90 m), which are silt, not clay as in profile C, Lowermost in the profile is a 15 cm thick layer A ulacoseira species predominate. Here, too, A. of clay overlain by silt with organic matter (Fig. islandica and its resting spores and A. !irala are 5). Only one sampie of the clay deposit was ana­ clearly dominant. Diploneis domblittensis Iysed for diatoms (at a depth of 11. 90 m). Fresh­ (Grunow) Cleve, Cymbella sinuata Gregory, water diatoms predominate in the sampie, with Stephanodiscus astraea s.l. (Ehrenberg) Grunow A ulacoseira islandica and its resting spores, A. and A. islandica are all considered to be great­ !irata and A . ita!ica var. va!ida (Grunow) Si mon­ lake species. This flora is typical of the Holocene sen as the main species. Cyclorella kiilzingiana Ancylus Lake stage of the Baltic Sea and similar and Melosira arenaria Moore are also fairly habitats. abundant. From a depth of 11 .75 m upwards the taxa are The lower part of the silt deposits and the sam­ composed almost exclusively of diatom flora pie at a depth of 10.30 mare poor in diatoms, typical of the Eemian Baltic Sea, and the species but otherwise the silt deposit contains the same are the same as those in the previous cores. rich Eemian Baltic Sea diatom flora as the previ­ Five sampies were studied from the till over­ ous profiles. Disrephanus speculum, Diclyocha lying the silt at a depth of 8-9 m (Fig. 6). Their fibula and Actiniscus pentasterias are also fairly loss-on-ignition is fairly high, 4-7 070, indicat­ abundant. The diatoms, classified according to ing a high content of reworked older organic their salinity demand are presented in Figure 5. material. The sam pies are moderately rich in The diagram also shows the silicoflagellates, and diatoms. Three of the sampies are composed Ebria rriparrita and Actiniscus pentasrerias alm ost exclusively of freshwater diatoms. The encountered. The abundances o f the latter are flora is typical of oligotrophie lakes, with abun­ given as pro mir curves calculated from the total dant species of the genera Pinnularia and Euno­ diatom abundance (Fig. 5) . tia. Diatoms of the genera Navicula, Neidium The diatom flora is composed almost exclu- and Cymbella are also present. The diatom flora 14 Geologieal Survey of Finland, Bulletin 352

Core 0 , Norinkylä T 1101 1 "----1 « ~.s. I I «w DIATOMS « Cl: 0 >- Ci i3 (/) >­ Z ;! z « I « ;! tl. POLYHALOBOUS :5 N (/) « g; >- ~ « « '!l 0 : ~ c.: (/)- I ~ ~ 0: -' Q. 0 -' >- Z « F (/) (/) ~ CD (!) w cn I GJ MESOHALOBOUS a: ~ I ; « Ci o 0 ~ üi ~ w -' 0 (/) ~ (/) w (/) W ~ Z « :5 :5 0: tl. 0 a: -' -' üi r­ I :5 « o UJ UJ z 0 8 Ö ~ I CD (/) OLiGOHALOBOUS 0. « .;J Q. I CD ~ EEl « Z Q. ::; ::; 9 -' -' 0 Z UJ Q. ~ ::: ~ >- >- ::; 6 6 « + « 0 a: (/) « ~ ~ Ci ::; _ 6 • + --l- .--l. I I I: :: ~ 8° Ff:=C'======::===~""""1 58

{', {', {', {', {', 1== ! {', I: i 535 . =:i _ t ~ •••• "•.•• __ ••.•_._ .•.•."_ .•• ••••_ ;...... ~.•••••••••••.•~." ••,~ .•••.•••.••••••• ~ . ~ ... ,-- --~ ....-:- ...... - ..,."'·.-;o.·"' ·.·;~~ ...... d / I /520 ,y~ f ; NO SAMPLES t I

530 i 500

1500

10 500 500 378 550 500 500 500 I 320 , 500 143 48 :: I 155 139 Ff-~- 35 rr 27

~~. .-t-~_. % 10 20 30 40 sO 60 70 80 90 10 20 30 40

~ TILL ::d SILl ~ GYTT JA SILl :8EI GYTlJA AND TlLL

Fig. 6. The diatom groups by salinity and some se lee ted freshwater speeies in eore D, orinkylä.

is comparable to that in CO re B at a depth of ously become intermixed with the till. 6.65-6.85 m. One of the sampies contains only The lower part of profile D deposited in a diatoms typical of the Eemian Baltic Sea, with freshwater basin of the Holocene Ancylus Lake Grammatophora oceanica and Hyalodiscus scoti· type, which was soon inundated by the Eemian cus as the dominant species. In the last subsam· Baltic Sea. The topmost part of the Eemian pie, mesohalobous diatoms are in the majority deposit, which contains materials from sea, (81 070), with lagoonal phase Campylodiscus lagoonal, isolation and lacustrine phases, was c/ypeus (67 0J0) as the dominant species. Material later pushed into the till layer covering it. from the underlying Eemian deposits has obvi· Geological Survey of Finland, Bullelin 352 15

OPEN SECTION OF THE HAAP ALANKA NGAS ESKER AT JU RVA

A silt deposit from a section in Haapalankan­ one metre of tiII, fo II owed by a silt layer and gas (Jurva) (62° 40' N, 21 °55' E), which is part 2 m of gravel, and uppermost is about 80 cm of of an adjoining tiII-covered esker chain, was also till. Diatoms are moderately abundant, although studied. This esker chain trends in the same direc­ the number of species is low. Aulacoseira islan­ tion as that studied by Niemelä and Tynni (1979) dica is overwhelmingly predominant, accounting and Donner (1988) but lies about 12 km funher for 78 070 of the taxa. Other freshwater diatoms north . The elevation of the section is 95 m a.s.1. are Amphora ovalis Kützing, Cyc/ote//a kützin• The silt studied is in the same stratigraphic posi­ giana, Cymatopleura e//iptica (Brebisson) W. tion as the silt in the co re profiles and in the sec­ Smith, Diploneis domblittensis (Grunow) Cleve ti on investigated by Niemelä and Tynni (1979) and Stephanodiscus astraea s. I. , all of which are and Donner (1988). found in Ancylus Lake sediments. The taxa also A silt layer encountered in the Haapalankan­ incJude some diatoms indicating saline water such gas section is about I m thick. The diatoms in as Grammatophora oceanica, AClinocyc/us küt• the layer were studied from a sampie taken at a zingii, Chaetoceros mitra (Bailey) Cleve and Nitz­ depth of 3 m. The stratigraphy of the section is schia punctata (W. Smith) Grunow. as folIows: lowermost is gravel overlain by about

THE UKONKANGAS SITE AT KÄ RSÄMÄKI

The Ukonkangas site at Kärsämäki is a polyhalobous, mesohalobous and oligohalobous gravel pit in a tiII covered esker (63 °55 ' 05' 'N, species. Some selected diatom species are also 25 ° 51 ' 40 ' ' E) (Fig. 7). Its elevation is the same shown. as that of Norinkylä, i.e. 110 m a.s.1. The site, The taxa in the silt below the sand layer are which is the easternmost of the Eemian sites the same as those interpreted as typical of the encountered in Ostrobothnia thus far, was fo und Eemian Baltic Sea, e.g. the species encountered by Hannu Peltoniemi in 1988 in the course of a at Norinkylä and earlier in Ostrobothnia (Nieme­ gravel resource inventory undenaken by the lä & Tynni 1979, Eriksson et al. 1980, Forsström Ministry of Roads and Waterways in Finland. et al. 1987, 1988, Grönlund 1988, Nenonen et al. The sam pies were taken by Matti Saarnisto in in press), the Karelian Isthmus (Brander 1937a 1989. The stratigraphy of the pit is as folIows: and b, 1941, 1943) and Prangli island (Cheremi­ lowermost is gravel followed by blue silt obvi­ sinova 1961, Liivrand 1984, 1987). Mesohalobous ously in situ overlain by laminated sand and diatoms predominate, with polyhalobous species gravel, and uppermost is about 2 m of compact accounting for slightly over 20 070 and oligohalo­ till. Silt occurs in the exposed section over a bous species for 5.4 070 at the most. Gram­ distance of about 15 m . The sampies for diatom matophora oceanica, Hyalodiscus scolicus, analysis were taken from the silt layer at a spot Melosira sulcata and Rhabdonema arcua(um are where the layer was about 0.5 m thick. the dominant species. The polyhalobous Po­ The silt contained diatoms in moderate abun­ dosira monlagnei is also fairly common. Of the dance, but none were found in the thin sand lay­ other polyhalobous species, mention should be er cutting the silt layer. The diatom flora is made of Actinocyc/us kützingii, Chaetoceros presented in Figure 8, where it is divided into mitra, C. subsecundus (Grunow) Hustedt, 16 Geological Survey o f Finla nd . Bulletin 35 2 SW NE m 110m osl. m O~------____------______~O

2 ----~-+2

4

o o o o o o o o o o o o o o o o o o o 6 6

o 5 10 15 20m ~ TILL c:=J SAt\ID I I LAMINATED SILT ~ GRAVEL SAND

Fig. 7. Section of the gravel pit in the Ukonka ngas (Kärsämäki) site.

Ukonkangas I 1 -' 1-

r 110m DIATOMS os I :;: :::> " ~ POLYHALO BOUS o>­ ~ ~ S u ­ ~ ~ ~ ::;: ::;: :;: u <{ w W z I 'Cl '2~ ~ o 0: 6 6 <:2 >- I - '3 o ro ro z 0: "- OliGOHALOBOU5 - w >­ o I I '2

POOR IN DIATOMS l 12 50 NO DIATOMS I 510 500 500 1 ~ J ~ ~ f ~ ::1 1530 I l ~-ti , ,~~ ~ , ,bi!------L J _ J L I ,I J --' % 10 10 20 30 1,0 50 60 70 80 90 100 10 20 10 20 105 5 5 10 10 20 30 10 20 30 10 10 10 10 10 20 Fig. 8. T he diatom groups by salinity and some selected dia tom species in the Ukonkangas site. Sediment symbols as in Figure 7. Geological Survey of Finland, Bulletin 352 17

Dimeregramma minor, Navicula glacialis and layer. Thalassiosira eccentrica. Campylodiscus clypeus, The till-covered silt at Ukonkangas deposited which is one of the lagoonal species, is encoun­ in the littoral phase of the Eemian Baltic Sea, tered in all sampies, but Amphora robusta and where the diatom flora is similar to that encoun­ Nitzschia scalaris of the same group occur only tered in the corresponding sediments in Os­ in some. trobothnia. As the flora includes diatoms indicat­ The silicoflagellates Distephanus speculum, D. ing a shallow lagoonal phase, the basin was prob­ speculum var. pentagonus Lemmerman, D. ably growing shallower and its water less saline. speculum var. septenarius and Dictyocha fibula Preliminary pollen analyses conducted at were encountered, as were Ebria tripartita and Ukonkangas show the presence of Betula, AInus Actiniscus pentasterias. and Pinus pollen with some low values of Picea The silt above the sand layer was markedly in the pollen stratigraphy of the silt layer. Also poorer in diatoms than was the underlying silt. present are pollen of Corylus, typical of the The number of species was also low, about half Eemian. This pollen assemblage refers to a very of them being freshwater diatoms. Aulacoseira constant vegetation, probably of the late tem­ islandica and its resting spores, Melosira are­ perate Eemian stage (B. Eriksson, oral commu­ naria, Stephanodiscus astraea s.l. and some spe­ nication). Temporally, the silt at Ukonkangas ob­ eies of the genus Pinnularia are included in the viously represents a rat her short period in the his­ diatom flora. The species indicating saline water tory of the Eemian Baltic Sea. are the same as those in the silt below the sand

DISCUSSION

Several sediment cores representing the Eemian tersected the older till below the sedimentary de­ interglacial are described above from Norinkylä posit, showing that the Eemian sediments are and sections from Ukonkangas and Haapalan­ sandwiched between two till layers differing in kangas. As the cores were discontinuous it is not age. possible to give a complete stratigraphie column. Three of the Norinkylä cores (A, C and D) The discontinuity of the sampie sets is partly due have sediments with freshwater diatoms as the to the difficulty of sampling, although it is lowermost unit. Two of these (A and C) are clay, feasible that the till-covered sedimentary deposits and one (D) is silt. At Haapalankangas, there is were initially incomplete, having been eroded and also one separate silt sam pie from a till-covered displaced by the overriding continental ice sheet. esker containing mainly freshwater diatoms. A At the Norinkylä site the peat deposit is feature shared by all the diatom assemblages is underlain by the till that covers the eskers in the the abundance of great-lake species , Amphora surroundings including the esker studied by ovalis, Aulacoseira islandica, A . islandica subsp. Niemelä and Tynni (1979) and Donner (1988), helvetica, Cymbella aspera, C. sinuata, Diploneis and Haapalankangas (Jurva). Drilling (Fig. 2) domblittensis, Melosira arenaria and Stepha­ revealed a layer of fine-grained sediment contain­ nodiscus astraea s.l. In addition to them, co re ing material of the Eemian Baltic Sea below this A contains abundant Aulacoseira lirala, common till . In holes drilled closer to the esker the fine­ in smaller lakes, and so me species of the genus grained sedimentary deposits also contain sand Pinnularia. The diatom flora encountered corre­ from the esker fringes. Successful drill holes in- lates with that in the clay below the Eemian Bal- 18 Geological Survey of Finland, Bulletin 352

tic Sea deposit at Viitala about 60 km to the (Clever-Euler 1953). Among the flora described northeast of Norinkylä (cf. Nenonen et al. in by Cheremisinova are the same species as those press). in the freshwater deposits underlying the Eemian According to available data, the sediment of deposits in Ostrobothnia. The greatest difference the lake preceding the Eemian Baltic Sea is direct­ is that Aulacoseira islandica, which is common ly overlain by a deposit of that sea only at in Ostrobothnia, is absent from the Prangli Norinkylä and Viitala in southern Ostrobothnia. deposit. In Ostrobothnia, particularly in the In the course of till studies in Ostrobothnia till­ lowermost sampies, the Aulacoseira species often covered sediments containing freshwater diatoms occur as resting spores, suggesting adverse, prob­ have been found, at some sites e.g. the Vesiperä ably cold, conditions. site (Nenonen et al. in press). These diatoms often The history 01' the Baltic Sea since the latest represent great-Iake diatoms (Ancylus Lake) in glaciation (Late Weichselian) includes the Baltic which Aulacoseira islandica and A. islandica lee Lake, which covered the area that emerged subsp. helvelica and their resting ~ . pores predomi­ from the ice sheet as far as the Salpausselkä mar­ nate. As these deposits are isolated, and diatoms ginal formations during Late Weichselian time, have not been encountered eithc:r above or be­ that is, before 10 000 B.P., and the Yoldia phase, low them, it is not possible to place them in the which started when the Baltic Ice Lake drained diatom stratigraphy. w ocean level. The Yoldia Sea preceded the Freshwater diatoms have also been found in­ Ancylus Lake, which is usually marked by a rise termixed with Eemian Sea flora (cf. Niemelä & in the number 01' diatoms. Information about the Tynni 1979). These deposits either refer to littoral diatoms of the two first mentioned stages (the areas of the Eemian Baltic Sea or then their dia­ Baltic lee Lake and the Yoldia Sea) is meagre; wm flora includes redeposited species. Fresh­ indeed these stages are marked by a scarcity of water diatoms, which are often encountered diatoms (cf. also Brunnberg & Miller 1990). It redeposited in till, may derive from interglacial is possible that muddy water from the thawing or interstadial freshwater deposits. ice was a Iimiting factor on the growth of According to Cheremisinova (1961) (see also diatoms. Aulacoseira islandica subsp. helvelica Liivrand 1987, in press), the diatom flora indicat­ is the most common diatom in the Baltic Ice ing cool fresh water, and interrnixed with the Lake. The Yoldia phase is characterized by a mix­ Eemian Baltic Sea diatom flora of encountered ture of brackish water, great fre hwater lake and in the Prangli deposit below the sediments of the small-lake diatoms. Aulacoseira islandica subsp. Eemian Baltic Sea, derive from a glacial lake helvelica is a common species in the Yoldia flora, invaded by the Eemian Baltic Sea. The glacial too. Assuming that post-glacial development in lake was comprised the basin of the Gulf of Fin­ the basin of the Eemian Baltic Sea was similar land and the lakes Ladoga and Onega. Its dia­ to that during the Holocene, it may weil be that tom flora contained cold freshwater relict spe­ the Eemian freshwater diatom flora encountered eies , such as the Cocconeis disculus (Schumann) in Ostrobothnia also contains older diatoms, Cleve, Diploneis domblittensis and D. domblir­ perhaps species similar 10 those of a glaciallake, tensis var. subconstricra A. Cleve mentioned by e.g. Aulacoseira islandica and A. islandica subsp. Cheremisinova. The flora also includes Stepha­ helvefica. The same may hold for the »cold water nodiscus aSlraea, Navicula luscula Eh ren berg, relict species» found on Prangli island. From the lvlelosira arenaria and species of the genera Pin­ a bove it follows that the freshwater sediments nularia, Epilhemia and Neidium. The cold water predating the Eemian marine sediments encoun­ relicts mentioned by Cheremisinova are also tered in Ostrobothnia and on Prangli island encountered in Holocene Ancylu5 Lake deposits mainly deposited in the same basin, which resem- Geological Survey of Finland, Bulletin 352 19 bled the Holocene Ancylus lake rather than a gla­ although there are some that thrive in cold water. ci al lake. This freshwater basin may contain The presence of these species confirms that the redeposited cold water species. Eemian Baltic Sea was connected with the Atlan­ In the Norinkylä deposit, the freshwater tic Ocean in the west and the White Sea in the deposit is overlain by silt that clearly deposited east. In terms of diatom flora, the situation was in the Eemian Baltic Sea. The silt layer varies in similar to that prevailing in the present Gulf of thickness, being thickest in core A. This vari­ Bothnia in relation to the Baltic Sea proper. ation may partly be due to the sampling, but it Besides saline species, the silts at Norinkylä mayaiso reflect primary depositional conditions. contain up to 20 % fresh water diatoms. At The diatom flora in the silt is of a type that flour­ Ukonkangas, freshwater diatoms account for a ishes in fairly saline water. The same diatom flora mere 2-3 %, excluding the uppermost sam pie, is also encountered in the silt at Ukonkangas. A which contains abundant diatoms, 50 % of them total of 152 taxa of diatom species indicating freshwater species. The sam pie probably refers saline water were named from the Norinkylä to a sea bay turning progressively less saline be­ cores, 89 of them polyhalobous and 63 meso halo­ fore being isolated as a freshwater basin due to bous (including meso- and pleioeyryhaline poly­ isostatic land uplift. The freshwater diatom flora halobous). Littoral diatoms predominate and pure in the till overlying the silt in core 0 at Norinky­ plankton diatoms are scarce. The mesohalobous lä mayaIso represent a post-isolation interglacial Grammatophora oceanica, G. oceanica var. ma­ freshwater basin. In other respects, the occur­ eilenta, Hyalodiscus scoticus, Rhabdonema arcua­ rence of freshwater diatoms in the silt deposits tum and Melosira sulcata are clearly dominant. In is probably due to the proximity of the shore. addition to them, the flora includes several spe­ The upper part of the silt deposit in core Bat ci es foreign to or very rare in the Holocene Norinkylä contains diatom flora indicative of a diatom flora of the Baltic Sea. These include lagoonal phase preceding the isolation of the ba­ Amphora acuta, Diploneis chersonensis, D. si n from the sea. T he beginning of the isolation crabro, D. mediterranea and D. schmidti, is recorded in the same profile at about a metre demonstrating that the water was more saline above the lagoonal sediments. In profile 0 the than in the Holocene Litorina stage. The salinity sediments of the lagoonal phase and isolation of the water is also indicated by silicoflagellates, were obviously mixed with the overlying til\. The Ebria lripartita and Actiniscus pentasterias. Ukonkangas si te shows the earlier part of a Many of the species favour warm water habitats, lagoonal phase.

CONCLUSION

Figures 9 and 10 summarize the stages of the 10 shows the same sites projected in accordance Eemian Baltic Sea based on data from deposits with the stages of the Eemian Baltic Sea. in Ostrobothnia. Figure 9 presents four new cores [t seems highly probable that, in the present horn Norinkylä, and the co res fro m Viitala basin of the Baltic Sea, the Eemian Baltic Sea was (l10 m a.s.l.) (Nenonen et al. in press), Evijärvi preceded by a lake stage with diatom flo ra simi­ (67 m a.s.\.) (Eriksson el al. 1980), Ukonkangas lar to that of the Holocene Ancylus Lake . T he (l1O m a.s.\.) and Ollala (125 m a.s.\.) (Forssträm Ancylus Lake was considerably larger than the et al. 1987) plotted in a south-north direction present Baltic Sea, partly because of the pro­ according to their elevation and location. Figure nounced glacio-isostatic depression of the crust 20 Geological Survey of Fi nland, Bulletin 352

Glr s N 120 ~

110-\ t> ~ [', [', [', [', [', [', Co. [', [', .~ 1111111111111 1001

00-

70 .J

6O ~ ... 111 Ü 0 '"co ~ 0> ,co ., C ,~ >-'" >-'" co -'">- ... : -'" co ' ~ c: c: -'"c: c: -'"c: co ';:: .~ 0 ]I '§ '5 '§ ~ 'S; -'" 1 S z 2": z z :> w ::J Ö N

_ Freshwater : ~ TIII L---...J Isolation ~ ~e~i;;"i!nt sediment

Fig. 9. The cores studied plotted with their elevations above the present sea level from south to non:l. within the Baltic basin. Sufficient data are not Many of the diatoms indicate highly saline and available for us to establish either the size or the warm water conditions. northern extent of the lake preceding the Eemian Diatoms indicating a lagoonal phase, the spe­ Baltic Sea. eies being the same as in the Clypeus flora All the above sites contain deposits of the encountered in the Holocene Litorina Sea, are Eemian Baltie Sea proper. Their diatom floras best represented in profile B at Norinkylä and, are rieh in species and very similar to eaeh other, intermixed with the overlying till, in profile D. representing littoral areas of the sea. Several spe­ The lagoonal phase is also recorded at the Evijär• eies are alien to later stages of the Baltic Sea. vi si te (Eriksson el al. 1980). Geologieal Survey of Finland , Bullet in 352 21

S N « aJ (J 0 V) '"Cl ,>.'" ,>.'" ,>.'" ,>.'" c: -" -" -" -" . ~ .§ c: c: c: '" -"'"c: 'C 'C '§ : ~ 0 '" 0 0 0 ~ ';; -" ~ z z z z :> UJ ::J (5

FRESHWATER

SEDIMENT 11 11 ISOLATION 11 11 n 11 11 LAGOONAL 11 11 SEDIMENT 11 11 11 I ~ EEMIAN SEA I SEDIMENT L

I ~ J FRESHWATER u SEDIMENT

not in scale

Fig , 10 , Sehematie stratigraphie sequenees aeeording to environmental ehanges in the Eemian Baltie Sea based on sediment eores from the sites studied.

The basin became progressively less saline until ments of the lake preceding the Eemian Baltic Sea ;t was fi nally isolated from the sea as an independ­ probably' deposited during the pre-temperate sub­ ent freshwater basin in the same way as later stage characterized by birch and pine. The basins were isolated from the Holocene Litorina deposits of the Eemian Baltic Sea proper accumu­ Sea and the present Baltic Sea. The isolation lated during the temperate sub tage characterized event is most clearly recorded at the O ll ala and by birch, alder, oak and hazel, and the isolation "Iorinkylä sites, although Evijärvi, too, shows in­ from the sea at the end of it (B. Eriksson, oral dications 0 f incipient isolation. communication). The core studied by Niemelä On the basis of a tentative poll en strati graphy and Tynni (1979) also referred to the temperate from the orinkyiä site (co res B and D) the sedi- substage. According to the schematic interglacial 22 Geological Survey of Finland, Bulletin 352

pollen diagram of Donner (1988, p. 26, Fig. 12), later. The pollen dating is in accordance with the the sediments from Norinkylä stuclied by Niemelä emergence history of the area. and Tynni (1979) predate those from the Evijär• According to Eriksson (oral communication), vi site, which can also be considered to represent it is likely that the sediments from the Ukonkan­ a temperate stage. The Evijärvi site is situated at gas site also deposited at the end of the temperate a lower elevation and thus emerged from the sea substage.

ACKNOWLEDGEMENTS

1 wish to thank Professors Urve Miller and useful discussions about till stratigraphy of Matti Saarnisto for critically reading the manu­ Ostrobothnia and for providing the material script and making valuable comments. from Norinkylä. I am also grateful to Brita Eriksson for our Pertti Hakala and Eila Paavilainen helped in many useful discussions, especially about pollen the field and in the laboratory, Satu Moberg did analysis, and Hannu Peltoniemi for providing the the drawings and Gillian Häkli translated the material from Ukonkangas. My warrnest thanks manuscript; to all of them I express my cordial are due to Heikki Hirvas and Kei jo Nenonen for thanks.

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Brander, G., 1937a. Ein Interglazial fund bei Rouhiala in Donner, J. 1988. The Eemian si te of Norinkylä compared Südfinnland. Bulletin de la Commission geologique Fin­ with Olher interglacial and interstadial sites in Ostroboth­ lande 118, 76 p. nia, western Finland. Annales Academiae Scientiarum Brander, G .• 1937b. Zur Deutung der intramoränen Ton­ Fennicae A. 111 , 149,31 p. ablagerungen an der Mga, unweit von Leningrad. Bulletin Eriksson, B., Grön1und, T. & Kujansuu, R. 1980. Inter­ de 1a Commission geo10gique Finlanje 119,93-114. glasiaalikerrostuma Evijärvellä Pohjanmaalla. Summary: Brander. G .. 1943. Neue Beiträge zur Kenntnis der interglazi­ An interglacial deposit at Evijärvi in the Pohjanmaa alen Bildungen in Finnland. Bulletin de la Commission region, Finland. Geologi 32, 65-71. geologique Finlande 128, 87-137. Eronen, M. 1974. The history of the Litorina Sea and Brunnberg, L. & Miller. U., 1990. Macro- and microfossils associated Holocene events. Commentationes Physico­ in late glacial clay from the Stock holm region, indicat­ Mathematicae. 44 (4), 79-195. ing brackish environment 10,400 years ago. In Lundqvist, forsström, L., Eronen. M. & Grönlund, T. 1987. On marine J. and Saarnisto, M. (editors): 1GCP 253 Termination phases and shore levels of the Eemian Interglacial and of the P1eistocene. Field conference Norway - Sweden Weichselian interstadials on the coast of Ostrobothnia, - Fin1and. May 9-16, 1990. Excurs.on and Abstracts. Finland. In Perttunen, :vi . (editor): Fennoscandian land Geo10gical Survey of Finland, Guide 31 , 102-104. uplift. Proceedings of a sy mposium at TVärminne, April Cheremisinova. E. A., 1961. Diatoms 01" the marine inter­ 10- 11 , 1986, arranged by the Finnish National Com­ glacial deposits in Estonian SSR. Dok1ady Akademii nauk mittee for Quaternary Research. Geological Survey of Fin­ SSSR 141 (3),698-700 (in Russian) . land, Special Paper 2, 37-42. C1eve-Euler, A. 1940. Das letztinterglaziak Baltikum und die forsström. L.. Aalto. M .. Eronen. M .. & Grönlund, T. 1988. Diatomeenanalyse. Beihefte zum Botanischen Centralblatt Stratigraphic evidence for Eemian cru tal movements and LX, B, 3, 287-334. relative ea-Ie\'el changes in eastern Fennoscandia. Palaeo­ eleve-Euler, A. 1953. Die Diatomeen ":ln Schweden und geograph)", Palaeoclimatology, Palaeoecology, 68, Finnland. Kungl. Svenska Vetenskapsakademiens Handl­ 31 7- 335. ingar 4: 5, 255 p. Garcfa Ambrosiani. K. 1990. ew investigations on the mac- Geological Survey of Finland, Bulletin 352 23

rofossils of the Bollnäs tillcovered sediments, Central Academy of sciences of the Estonian SSR . Geology, 36 Sweden. In Garcia Ambrosiani, K. 1990: Pleistocene (I), 20-26. stratigraphy of Central and Northern Sweden - a rein­ Li ivra nd, E., Biostratigraphy of the Pleistocene deposits in vestigation of some cIassical sites. University of Stock­ Estonia with correlations in the Baltic region. University hoim, Department of Quaternary Research, Report 16, of Stockholm. Department of Quaternary Research, 11, 12 p . Report (in press). Gibbard, P ., Forman, S., Salomaa, R. , Alh onen, P., Jungner, Miller, U. 1964. Diatom floras in the Quaternary of the Göta H ., Peglar, S., Suksi, J . & Vuorinen, A. 1989. Late river valley (western Sweden). Sveriges geologiska under­ Pleistocene stratigraphy at Harrinkangas, Kauhajoki, sökning Ca 44, 67 p. Western Finland. Annales Academiae Scientiarum Fen­ Miller, U. & Persson, C. 1973. A lump of cIay embedded in nicae A. 11I, 150,36 p. gJacial intermorainic sand. GeoJogiska Föreningens i Grönlund, T., 1988. The diatom flora of the Eemian deposits Stock holm Förhandlingar 95, 342-346. at Haapavesi, western Finland. Geological Survey of Fin­ Möld er, K. & Tynni, R. 1967. Über Finnlands rezente und land, Report of Investigation 79, 14 p. subfossile Diatomeen I. Comptes Rendus de la Societe Grönlund, T. The lagoonal diatom flora of the Holocene Bal­ geologique de Finlande XXXIX, 199-217. tic Litorina Sea in comparison with the Eemian Baltic Sea Ne nonen, K., Eriksson, B. & G rö nlund , T. The till stratig­ flora. Proceedings of the Eleventh InternationalDiatom raphy of Ostrobothnia, western Finland, with reference Symposium San Francisco, California August 12- 17, to new Eemian interglacial sites. In Andersen, B. G. and 1990, (in press). Königsson , L.-K. (editors): Late Quaternary Stratigraphy Grö nlund, T ., Hirvas, H ., Ik onen, L. & Ne no nen, K. 1985. in the Nordic Countries 150.000-15.000 B.P. Striae, 34, Ojalanperä, Vihanti: Fragments of organic material within (in press .) an older till bed. In Saarnisto, M. (editor): INQUA till Niemelä, J . & Tynni , R. 1979. InterglaciaJ and interstadial symposium. Field workshop August 20-29, 1985 , Ex­ sediments in the Pohjanmaa region, FinJand. Geological cursion guide, Geological Survey of Finland, Department Survey of FinJand, Bulletin 302, 48 p. Quaternary Geology, Espoo, 83-89. Pässe, T., Robertsson, A.-M., Miller, U. & Klinberg, F. 1988. G uillard , R.R.L. & Kilham, P . 1977. The ecology of marine A Late Pleistocene sequence at Margareteberg, south­ planktonic Diatoms. In Werner, D. (editor): The biology western Sweden. Boreas, 17 , 141-163. of Diatoms. Botanical Monographs 13, 372-469. Round, F. E. 1981. The ecology of algae. Cambridge Univer­ Hald en, B. E:son, 1915. Det interglaciala Bollnäsfyndets sity Press, Cambridge, 653 p. stratigrafi. Geologiska Föreningens i Stock holm Förhand• Sancetta, C. 1990. Seasonal occurrence of silicoflagellatae lingar 37, 452-479. morphologies in different environments of the eastern Pa­ Hartley, B. 1986. A check-list of the freshwater, brackish and cific Ocean. Marine Micropaleontology 16, 285-291. marine diatoms of the British Isles and adjoining coastal Schrader, H.J . & Richert , P. 1974. PaJeotemperalUre interpre­ \Vaters. Journal of the Marine Biological Association of tation by means of percent amount of Diclyocha/ the United Kingdom 66,531-610. Dislephanus (Silicoflagellatae). Abstract in Marine Plank­ Hend ey, N. 1. , 1964. An introductory account of the smaller ton and sediments, 3rd Planktonic Conference, Kiel. algae of British coastal waters. Ministry of Agriculture, Sim onse n, R. 1962. Untersuchungen zur Systematik und Fisheries and Food, Fishery investigations IV. V, Lon­ Ökologie der Bodendiatomeen der westlichen Ostsee. In ­ don. 317 p. ternationale Revue der gesamten Hydrobiologie I, 144 p. Hustedt, F. 1930. Die Kieselalgen Deutsch lands, Österreichs Simonsen, R. 1979. The diatom system: Ideas on phylogeny. und der Schweiz 1-11. Rabenhorst 's Kryptogamen-Flora Baci ll aria 2, 9-71. Band VlI , 920 p, Leipzig 736 p. Tynni , R. 1971. The diatoms in the Somero clay. In Don­ Hyy ppä, E. 1966. The late-Quaternary land uplift in the Baltic ner, J. and Gardemeister , R.: Redeposited Eemian ma­ sphere and the relation diagram of the raised and tilted rine cIay in Somero south-western Finland. Bulletin of shore levels. Annales Academiae Scientiarum Fennicae, the Geological Societ)' of Finland. 43, 85-88. Sero A. 111 ,90, 153-168. Zans, V. 1936. Das letzt interglaziale Portlandia-Meer des Bal ­ Liivrand , E., 1984. The Interglacials of Estonia. Annales tikums. Bulletin de la Commission geologique de Fin­ Academiae Scientiarum Fennicae A. 11I , 138, 16 p. lande 115, 231-250. Liivrand , E., 1987. Regional type section of the Eemian marine deposits on Suur-Prangli. Proceedings of the Geological Survey of Finland, Bulletin 352

Plale I

Fig. I. Amphora crassa Gregory 2. Amphora acuta Gregory 3. Stephanopyxis turris (Greville) Ralfs 4. Actiniscus pentasterias Ehrenberg 5. Thalassiosira gravida eleve 6. Amphora costata W. Smith 7. Campylodiscus clypeus Ehrenberg 8. Distephanus speculum (Ehren berg) Haeckel 9. Dictyocha fibula Ehrenberg 10. Nitzschia scalaris W. Smith Geological Survey of Finland, Bulletin 352 Plate I

10~m Geological Survey of Finland, Bulletin 352

Pla t

Fig. 1. Podosira hormoides (Montagne) Kützing 2. Podosira hormoides (Montagne) Kützing 3. Diploneis chersonensis (Grunow) eleve 4. Diploneis crabro Ehrenberg 5. Podosira mOnlagnei Kützing 6. Podosira mOnlagnei Kützing 7. Cocconeis COSlala Gregory 8. Rhi~osolenia hebelala Jor. hiell7alis Gran 9. Glyphodesmis dislans (Gregory) Grunow 10. Navicula opunlioides Simonsen 11. Rhizosolenia hebelala Jor. hiemalis Gran Geological Survey of Finland, Bulletin 352 Plate 11

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