GEOLOGICA CARPATHICA, 49, 5, BRATISLAVA, OCTOBER 1998
351368
PALEOECOLOGY OF THE LATE MIOCENE MAAR LAKES,
PODREÈANY BASALT FORMATION, SOUTHERN SLOVAKIA,
ON THE BASIS OF SILICEOUS MICROFOSSILS
NADJA OGNJANOVA-RUMENOVA
1
and DIONÝZ VASS
2
1
Department of Palaeontology & Stratigraphy, Institute of Geology, Bulgarian Academy of Sciences,
Acad. G. Bonchev str., Blgd. 24, BG-1113 Sofia, Bulgaria
2
Faculty of Forestry, Technical University Zvolen, Masarykova 24, 960 53 Zvolen, Slovak Republic
(Manuscript received February 16, 1998; accepted in revised form June 16, 1998)
Abstract: The siliceous microfossilsdiatom and chrysophycean stomatocystaeof the diatomite and alginite from
two maars (Jelovec and Pinciná) of the Late Miocene Podreèany Basalt Formation in Southern Slovakia have been
studied. The ecological analysis of the microfossils studied points to a shallow lake environment with pH = 78,
salinity of 0.30.5 %, temperate climate. The nutrient spectrum from the Jelovec maar where diatomite was depos-
ited suggest an oscillation of oligotrophic and eutrophic conditions. In Pinciná maar where alginite was deposited the
eutrophic conditions prevailed. The exellent state of Botryococus braunii soft bodies preservation points to a strati-
fied water column in the lake with anearobic conditions at the bottom. In the Jelovec maar organic matter is practi-
cally missing. The water column was not stratified, even the bottom water was oxygenated and oligotrophic condi-
tions prevailed.
Key words: Neogene (Pontian), paleoecology, biostratigraphy, maars, diatoms, chrysophycean stomatocystae.
Material and methods
Eleven samples from three boreholes (VPA-1,2 Pinciná;
VJA-2 Jelovec) were studied. The strata consisted of lapilli
tuff, volcanic sandstones, tufaceous clay, diatomitic clay and
diatomites and they belonged to the Podreèany Basalt For-
mation (Fig. 1). Radiometric data from the basalt volcanism
responsible for the maars suggested an age of 6.176.45 Ma
(Balogh et al. 1981).
The preparation and analysis of diatom samples followed the
procedure of Ognjanova-Rumenova (1991). Abundance calls
Introduction
Two maars of the Podreèany Basalt Formation are filled by
strictly different sediments. Pinciná maar contains alginite
rich in organic matter of the Botryococus braunii a taxon
of the Algae. Jelovec maar, situated only few kilometers
from Pinciná, contains diatomite poor in organic matter but
rich in siliceous armours of Diatomaceae another group be-
longing to the Algae. Looking for the reason for such strong
diversity one of us (O.-R.) studied the Diatomaceae from
both maars.
One of first announcement of the existence of a nonmarine
diatom flora in Neogene sediments of the Western Car-
pathians (Slovakia) was the publication of Pantocsek (1886
1905). Øeháková (1960, 1971, 1980) presented detailed in-
formation about the diatom paleontology and biostratigraphy.
A preliminary study of diatom flora comming from the diato-
mite outcropping at the margin of Pinciná maar has been
done by Èierna (in Vass & Eleèko et al. 1992). The aim of
this study is to trace the siliceous microfossil successions
(diatom and chrysophycean stomatocystae) in the maars of
Jelovec and Pinciná, Southern Slovakia, and to reconstruct
the paleoenvironmental changes during the time of sedimen-
tation in both maars. Former study of Neogene diatoms oc-
curring in similar basalt maars filled by alginite of Western
Hungary is this of Hajós (1990). Majority of taxa described
by Hajós have also been found in Pinciná maar. The ecologi-
cal conditions were also found to be identical. Only the salin-
ity seems to be less in the Pinciná and Jelovec maars.
Fig. 1. Relicts of the Podreèany Basalt Formation (Pontian) in the
Luèenec Depression. 1 lava flow, 2 maar, 3 Poltár Fm.,
4 lava flow direction, 5 pre-Pontian rocks.
352 OGNJANOVA-RUMENOVA
and VASS
were made according to Schraders scale (Schrader 1973). Dia-
toms were identified mainly using standard floras and selected
relative papers. To confirm and document the identifications,
some samples were subjected to scanning electron microscopi-
cal (SEM) investigation after Hasle & Fryxell (1970). The ob-
servations were made on Jeol JSM T 300. The spectra of physi-
co-chemical tolerances based on studies of modern diatoms
were used to interpret the paleoecological data (Van Landing-
ham 1967; Abbott & Van Landingham 1972). The ratio between
diatom frustules and chrysophycean stomatocystae was deter-
mined as a trophic status index in temperate lake sediments
(Smol 1985).
Geological setting
The maars of Jelovec and Pinciná are products of a vast ba-
saltic volcanic activity in the Pannonian Basin (W. Hungary)
and at the southern margin of the Western Carpathians (S. Slo-
vakia) at the end of the Miocene and during the Pliocene and
Pleistocene. In Slovakia the bulk of the basaltic volcanics is
subdivided into the Podreèany and Cerová Basalt Formations.
The Podreèany Formation spreads in the Luèenská kotlina De-
pression and is olderPontian in ageas is well proved by ra-
diometric ages (76 Ma); Balogh et al. (1981), Kantor & Wieg-
erová (1981) and by palinological data coming from the Poltár
sedimentary formation genetically closely related to the Po-
dreèany Basalt Formation (Planderová 1986; Vass & Eleèko et
al. 1992; Vass et al. 1997). The basalt lava flows interfinger with
river deposits of the Poltár Formation. The Pinciná and Jelovec
maars both belong to the Podreèany Basalt Formation (Fig. 1).
A maar, as usual, is formed by a circular or elliptic ring com-
posed mostly of bedded lapilli tuff. The central part of a maar is
filled by pelitic sedimentary rocks. There is significant differ-
ence between the sedimentary infill of the two maars. The
Pinciná maar is filled by dark bituminous laminated pelitic rock
alginite. The dark laminae are rich in Botryococcus braunii
Kütz. remnants. Finer bright laminae are rich in diatoms. The
Jelovec maar is filled by bright or bright-gray mostly laminat-
ed, light pelitic rock rich in diatoms diatomite.
The pelitic infill was deposited in the maar crater. After ces-
sation of the freatomagmatic eruptions responsible for the ori-
gin of the crater and the maar rings the maar was filled by the
precipitation water and small lake came to existence. In the
lake algae found excellent living condition and lake was
quickly occupied by them. On the bottom of the lake, dead al-
gal bodies and/or colonies were deposited together with clay
material washed into the lake from the quickly weathered
lapilli tuffs of the maar ring. The results of the lake deposition
were: in the organic matter rich alginite (Pinciná) and in the
siliceous skeletons, or armours of Diatomaceae rich diatomite
(Jelovec).
The pairs of dark and bright laminae in alginite represent an-
nual deposits. The mean thickness of pair is about 2 mm. Be-
cause the maximal ascertained alginite thickness in Pinciná
maar is 47.1 m (Vass et al. 1997) the deposition time was
aprox. 23,550 years.
Schematic profiles of the boreholes, the studied samples
come from, are shown in Figs. 7 and 8.
Results and discussion
The diatom flora and community structure
The diatom taxa are presented following the classification
order of Glezer et al. (1988) with some inclusions according
to Round et al. (1990) and Krammer & Lange-Bertalot (1986-
1991) (Table 1). These taxonomical data are accompanied by
ecological and distributional information. The tabular summa-
ry provides a frame of reference which facilitates the charac-
terization of the diatom flora and permits a more concise con-
ceptual basis for the interpretation of environmental
conditions. A total of 181 taxa are observed in the present
study. They refer to 35 genera, 128 species, 37 varieties and 6
formae, and belong to 13 families, 4 orders and classes Cen-
trophyceaea and Pennatophyceaea. Diatoms were identified
to species whenever possible; however ten entities could be
assigned to genus only. The diatom flora mostly consists of
modern species 92.4 %, but the group of extinct species
(7.6 %) is abundant in some levels (i.e. Pliocaenicus omar-
ensis (Kütz.) Round & Hak., Aulacoseira distans var. scala
(Ehr.) nov. comb, etc.). In general, pennate forms are the
most varied (94.5 %). The species rich genera Navicula
Bory and Cymbella Ag. can be distinguished, they account
for 26.5 % of the entire flora. These are followed by the
genera Pinnularia Ehr. (8.8 %), Fragilaria Lyngb. (7.2 %),
Achnanthes Bory (7.2 %) and Gomphonema Ehr. (6.1 %).
The class Centrophyceae accounts for 5.5 % of the diatom
flora. More of its representatives are widely spread, in
some levels they are rock-forming and occur as dominants
or subdominants.
Chrysophycean stomatocystae are the second major sili-
ceous microfossil group present in the investigated sediments.
These are the endogenously-formed siliceous stomatocystae
(also called statospores or resting cysts) which are widely be-
lieved to be taxon specific. The advances in paleolimnological
techniques and taxonomy of the past decade have led to wide-
spread interest in the use of chrysophycean microfossils as pa-
leoindicators. The contribution of chrysophytes to total algal
biomass tends to drop with increasing lake productivity, or
eutrophication as also suggested by the index of Smol (1985).
Changes in microfloral assemblages with depth have been
investigated in three borehole sequences. The diatom diagrams
(Figs. 2, 3) have been compiled using taxa with abundances
corresponding to 45 of Schraders scale (Schrader 1973).
In the well VPA-1, Pinciná two assemblages can be distin-
guished in the development of diatom flora. From 26.30 m to
13.20 m the most abundant species is a very small form of ge-
nus Cyclotella Kütz. (dimensions Diameter of the discs:
5.421.4 µm; Striae: 1618 per 10 µm; Diameter of the central
area: 0.984.9
µ
m). The valve morphology is very similar, but
not identical to C. iris Brun. & Herib. and allied forms. (Pl. I:
Figs. 13; Pl. V: Figs. 14; Pl. VI: Figs. 14). Probably this is
a separate species, which will be described. The abundance of
the accompanying species is estimated at 23 according to
Schraders scale i.e. the species of genus Fragilaria Lyngb.
occur occasionally F. construens (Ehr.) Grun. and F. virescens
Ralfs. Within this range we observed poor occurrence of repre-
sentatives of the genus Aulacoseira Thw., but Gyrosigma
PALEOECOLOGY OF THE LATE MIOCENE MAAR LAKES 353
genus Fragilaria Lyngb.: F. leptostauron (Ehr.) Hust., F.
martyi (Herib.) L.-Bert., F. transylvanica Pant. Another in-
teresting find is the occurrence here of an unidentified form
of the genus Tabellaria Ehr. (Pl. I: Figs. 1415; Pl. VII: Figs.
13) The abundance of the accompanying species Eunotia
Ehr. is remarkable.
Fig. 3. Diatom diagram from bore-hole VJA-2, Jelovec. 1. abun-
dant species, 2. common species, 3. frequent species, 4. rare species.
Fig. 2. Diatom diagram from bore-hole VPA-1, Pinciná. 1. abundant
species, 2. common species, 3. frequent species, 4. rare species.
Fig. 4. Histograms (IIV). Percentage ratio of the ecological groups
of diatoms from the Upper Miocene sediments, VPA-1, 3 Pinciná
and VJA-2, Jelovec. I. pH spectrum: 1. alkaliphilic, 2. acidophilic,
3. alkalibiontic, 4. indifferent. II. Halobion spectrum: 1. halo-
phobous, 2. halophilous, 3. indifferent, 4. mesohalobous. III. Habi-
tat spectrum: 1. planktonic; 2. periphytic (epiphytic); 3. periphytic
(deep water forms). IV. Geographical distribution: 1. cosmopoli-
tans, 2. north-alpine forms, 3. boreal forms, 4. tropical forms.
acuminatum (Kütz.) Rabenh. and Cymbella sp. are frequent.
Their mass development coincides with the increase in the
quantity of Tetracyclus glans (Ehr.) Mills. Species of other
algal remains Pediastrum sp. have also been found in
large quantities in the sample at 26.30 m. These species are
used as indicators of high carbon percentage (Haworth
1989).
The second assemblage occurs in sediments at the level of
13.205.90 m. The representatives of genus Aulacoseira
Thw. are abundant. Apart from two transition species A.
granulata (Ehr.) Sim. and A. distans var. scala (Ehr.)
nov.comb., A. valida (Grun.) Kramm. is very frequent within
this range. It is noteworthy that at this level Stephanodiscus
minutulus (Kütz.) Cl. & Moller and Pliocaenicus omarensis
(Kütz.) Round & Hak. are dominant. Their appearance and
development coincides with those of species belonging to the
354 OGNJANOVA-RUMENOVA
and VASS
Fig. 6. Percentage diagrams of the ecological diatom groups from borehole VJA-2 Jelovec.
Fig. 5. Percentage diagrams of the ecological diatom groups from borehole VPA-1 Pinciná.
PALEOECOLOGY OF THE LATE MIOCENE MAAR LAKES 355
Table 1: List of the diatom taxa found in this study with their range, abundance in depth and ecology. Range: lEo Late Eocene; Ol Oli-
gocene; N Neogene; Mi Miocene; eMi Early Miocene; lMi Late Miocene; Pl Pliocene; ePl Early Pliocene; Q Quaterna-
ry; Plei Pleistocene, Hol Holocene, R Recent. Abundance: 2 rare species; 3 frequent species; 4 common species; 5
abundant species. Ecology: habitat: pl planktonic; ep periphytic (epiphytic); d periphytic (deep water form); halobity: hb halo-
phobous; I indifferent; hl halophilous; mhb mesohalobous; pH: ac acidophilic; alk alkaliphilic; albnt alkalibiontic; I in-
different; geographical distribution: c cosmopolitans; n-a north-alpine forms; b boreal forms; tr tropical forms.
DIATOMS
R ANGE
VPA-1 Pinciná
VPA-3
Pinciná VJ A-2 J elovec
Ecology
5.90-6.00m
10.00-10.10m
13.20m
18.30m
26.30m
24.50m
37.60m
.6.50-7.00m
11.10m
13.10m.
17.10m
habitat
halobity
pH
geographical
distribution
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
17
Stephanodiscus as trea var. intermedia Fricke, 1901
lMi - R
2
pl
i
alk
b
S. minutulus /Kütz./Cleve & Moller, 1878
lMi - R
5
2
5
5
5
pl
i albnt
c
Cyclotella sp.
5
5
5
5
5
3
Pliocaenicus omarensis /Kütz./R ound & Hakansson, 1992
Pl
2
5
Aulacoseira ambigua /Grun./Simonsen, 1979
Mi-R
5
5
pl
i
alk
c
A. distans var. scala /Ehr./nov. comb.
lMi-Pl
5
3
5
3
3
3
5
3
3
A. granulata /Ehr./Simonsen, 1979
Ol-R
3
3
5
4
3
4
3
4
4
3
pl
i
alk
c
A. granulata var. angustissima /O.Mull./Simonsen, 1979
Ol-R
3
pl
i
alk
c
A. italica /Ehr./Simonsen, 1979
lEo-R
2
pl
i
alk
c
A. valida /Grun./Krammer, 1990
Mi-R
3
5
4
pl
i
alk
n-a
Frag ilaria biceps /Kütz./ Lange-Bertalot, 1991
N-R
3
ep
i
i
c
F. bituminosa Pantoscek, 1889
lMi-Pl
3
F. bre vis triata Grunow, 1885
Ol-R
3
2
4
3
2
3
3
ep
i
alk
c
F. cons true ns /Ehr./Grunow, 1862
Ol-R
3
3
3
3
3
4
3
2
3
3
ep
i
alk
c
F. cons true ns f. binodis /Ehr./Hustedt, 1957
Mi-R
3
3
3
2
ep
i
alk
c
F. cons true ns f. subsalina /Hust./Hustedt, 1957
Ol-R
2
3
ep
hl
alk
c
F. cons true ns f. venter /Ehr./Hustedt, 1957
Ol-R
3
3
3
3
4
4
3
5
5
ep
i
alk
c
F. le ptostauron /Ehr./Hustedt, 1931
Ol-R
4
2
3
2
d
hb alk
b
F. martyi /Herib./ Lange-Bertalot, 1993
lMi-R
2
4
3
2
3
4
3
2
2
ep
i
alk
c
F. trans ylvanica Pantocsek, 1892
lMi-ePl
5
3
3
F. ulna var. amphirhynchus /Ehr./Valeva & Temnisk., 1993
Plei-R
3
ep
i
alk
c
F. vires cens R alfs, 1843
lEo-R
3
2
3
2
ep
hb
i
c
Synedra rumpens var. fragilarioides Grunow, 1881
Plei-R
2
ep
i
c
Asterionella ralfs ii W . Smith, 1856
R
5
pl
i
alk
c
Tabellaria fenes trata /Lyngb./Kützing, 1844
eMi-R
2
3
ep
hb ac
c
T. flocculos a /R oth/Kützing, 1844
eMi-R
2
2
ep
hb ac
n-a
T. poretzkiae Loginova & Chursevich, 1980
ePl
2
Tabe llaria sp.
5
5
3
4
2
Tetracyclus emarginatus /Ehr./W .Smith, 1856
Mi-R
3
3
3
3
3
3
2
ep
i
i
n-a
T. glans /Ehr./Mills, 1835
eMi-R
4
4
3
5
2
5
3
2
2
ep
i
ac
n-a
T. s tellare Heribaud, 1903
lMi
2
2
Navicula abiskoe ns is Hustedt, 1942
Pl-R
2
d
i
i
n-a
N. amphibola Cleve, 1891
Mi-R
2
2
2
3
2
2
d
i
alk
n-a
N. arenariaeformis Pantocsek, 1889
Pl
3
3
3
3
N. arenariaeformis var. major Gasse, 1980
Pl
3
3
N. cari Ehrenberg, 1836
Pl-R
2
4
2
2
2
3
3
3
ep
i
i
c
N. cincta (Ehr.) R alfs, 1861
Mi-R
3
d
hl
alk
c
N. costulata Gunow, 1880
Q-R
2
3
3
3
2
3
d
hl
alk
c
N. cryptoce phala Kützing, 1844
Mi-R
2
d
i
alk
c
N. cuspidata /Kütz./Kützing, 1844
Mi-R
2
2
3
2
ep
i
alk
c
N. digitoradiata /Greg./ R alfs, 1861
Mi-R
3
5
3
3
3
5
5
3
4
3
2
d mhb alk
c
N. gastrum /Ehr./Kützing, 1844
Mi-R
2
2
2
3
3
3
3
3
ep
i
i
c
N. hasta Pantocsek, 1892
Mi-R
2
4
3
3
3
3
d
i
i
c
N. lance olata /Ag./Ehrenberg, 1838
Mi-R
2
2
3
ep
i
alk
c
N. lateros trata Hustedt, 1925
Pl-R
3
d
i
alk
c
N. menis culus Schumann, 1867
Mi-R
2
2
d
hl
alk
c
N. place ntula /Ehr./Kützing, 1844
eMi-R
2
2
2
2
d
i
alk
c
N. platys toma var. pantocsekii W isl. et Kolbe, 1927
Q-R
2
2
N. protracta /Grun./ Cleve, 1894
Pl-R
2
2
d
hl
i
c
N. protracta /Grun./Cl. f. subcapitata /W isl. & Poretz. / Hustedt, 1962
Pl-R
2
d
hl
b
356 OGNJANOVA-RUMENOVA
and VASS
DIATOMS
R ANGE
VPA-1 P inciná
VPA-3
P inciná VJ A-2 J elovec
E cology
5.90-6.00m
10.00-10.10m
13.20m
18.30m
26.30m
24.50m
37.60m
.6.50-7.00m
11.10m
13.10m.
17.10m
habitat
halobity
pH
geographical
distribution
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
N. ps e udoanglic a Lange-Bertalot, 1985
Mi-R
2
3
2
3
2
3
3
d
i
alk
b
N. ps e udolanc e olata var. de ns e line olata L.Bertalot, 1985
R
2
N. radios a Kützing, 1844
eMi-R
3
3
3
ep
i
i
c
N. re inhardtii Grunow, 1877
Mi-R
2
d
i
albnt
c
N. s c ute lloide s W .Smith, 1856
Mi-R
2
ep
i
albnt
c
N. tus cula E hrenberg, 1841
P l-R
2
3
3
3
2
4
4
d
i
albnt
c
Navic ula s p. 1
2
S ellap h ora bac illum /E hr./Mann, 1989
Mi-R
3
3
3
3
2
3
4
3
3
2
d
i
alk
b
S. pupula /Kütz./Mann, 1989
Mi-R
3
2
d
i
i
c
S. pupula var. capitata /Hust./nova comb.
eP l-R
3
i
i
c
S. pupula var. re ctangularis /Greg./ Ognjanova 1991
Mi-R
2
ep
i
i
c
An o moeo neis s phae rophora /Kütz./P fitzer, 1871
Mi-R
2
2
ep
hl albnt
c
S tauron eis anc e ps E hrenberg, 1843
Mi-R
3
3
3
2
3
3
2
d
i
i
c
S. phoe nic e nte ron /Nitzsch/E hrenberg, 1843
Ol-R
4
4
4
4
2
5
4
2
ep
i
i
b
S. produc ta Grunow, 1880
Mi -R
2
ep
hl
S. s m ithii Grunow, 1860
Mi-R
2
2
2
2
d
i
i
c
S. s m ithii var. incis a P antocsek, 1902
P l-R
3
3
2
d
i
alk
c
Gyro sig ma ac um inatum /Kütz./R abenhorst, 1853
eP l-R
2
4
3
3
3
2
ep
i
albnt
c
Pin nu laria ac ros phae ria R abenhorst, 1853
R
2
d
i
albnt
c
P. bore alis E hrenberg, 1843
Mi-R
2
2
2
3
d
i
i
c
P. braunii var. am phicephala /Mayer/Hustedt, 1930
Mi-R
3
3
2
3
4
3
d
hb
i
c
P. dis tingue nda C leve, 1895
lMi-R
2
d
hl
P. e s ox E hrenberg, 1843
lMi-R
3
2
2
d
c
P. he m ipte ra f. de ns e striata Tynni, 1976
R
2
P. inte rrupta W .Smith, 1853
lMi-R
3
3
3
4
3
3
5
d
i
ac
c
P. m acile nta /E hr./ Cleve, 1895
R
3
c
P. m aior /Kütz./R abenhorst, 1853
eMi -R
2
3
d
i
i
c
P. m aior var. lacus tris Me ister, 1912
Q-R
2
2
P. m ic ros tauron /E hr./Cleve, 1891
eMi-R
2
2
i
c
P. m ic ros tauron var. am bigua Meister, 1912
R
2
d
i
i
b
P. m ic ros tauron var. bre bis s onii /Kütz./Mayer, 1912
lE o-R
3
d
i
i
c
P. nobilis var. ne oge na /Grun./Cleve, 1895
eMi-Q
2
P. viridis /Nitzsch/Ehrenberg, 1843
eMi-R
3
3
2
2
3
3
3
d
i
i
c
P. viridis var. le ptogongyla /Grun./Cleve, 1895
eP l-R
3
2
2
2
2
d
i
i
b
Calon eis bac illum /Grun./Cleve, 1894
eP l-R
2
2
2
3
3
2
2
ep
i
alk
c
C . le ptos om a (Grun.)Krammer, 1985
R
2
C . s ilicula var. kje llm aniana /Grun./Cleve, 1894
P l-R
2
d mhb albnt
b
Diplo neis e lliptic a /Kütz./C leve, 1891
Mi-R
3
3
4
2
3
4
4
4
4
5
ep
i
alk
c
D. m argine s triata Hustedt, 1922
P lei-R
2
d
i
alk
n-a
Neidium affine /E hr./Pfitzer, 1871
lMi-R
2
2
i
alk
c
N. am pliatum /E hr./Krammer, 1985
P l-R
3
2
3
2
d
i
i
b
N. dubium /E hr./Cleve, 1894
eP l-R
2
d
i
i
n-a
N. produc tum /W .S m./ C leve, 1894
P l-R
2
2
d
hb
ac
c
Ne idium s p.
2
F rustulia rhom boide s /E hr./De Toni, 1891
eMi-R
2
d
hb
ac
n-a
Masto g loia s m ithii Thw. var. lacus tris Grunow, 1878
P lei-R
3
ep
hl
alk
c
Co ccon eis plac e ntula E hrenberg, 1838
Ol - R
3
2
4
4
3
ep
i
alk
c
C . place ntula var. e uglypta /E hr./Grunow, 1884
Mi-R
2
2
2
2
3
2
ep
i
alk
c
Ach n an th es c le ve i Grunow, 1880
R
2
ep
i
alk
c
A. cle ve i var. rostrata Hustedt, 1930
P l - R
2
d
i
alk
b
A. cons pic ua Mayer, 1919
Ol-R
2
2
ep
i
alk
b
A. e xigua Grunow, 1880
Mi-R
2
3
ep
i
alk
c
A. e xilis Kützing, 1833
R
2
c
A. fle xe lla (Kütz.) Brun, 1880
R
3
3
3
3
3
3
3
ep
hb
ac
c
A. hauc kiana Grunow, 1880
Mi-R
2
2
2
3
3
hl albnt
c
A. lanc e olata /Breb./Grunow, 1880
Mi-R
2
2
ep
i
alk
c
PALEOECOLOGY OF THE LATE MIOCENE MAAR LAKES 357
DIATOMS
R ANGE
VPA-1 Pinciná
VPA-3
Pinciná VJ A-2 J elovec
Ecology
5.90-6.00m
10.00-10.10m
13.20m
18.30m
26.30m
24.50m
37.60m
.6.50-7.00m
11.10m
13.10m
.
17.10m
habi
ta
t
hal
obi
ty
pH
geogr
aphi
cal
di
st
ri
but
io
n
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
A. lanceolata subsp. rostrata /Oestr./Lange Bertalot, 1991
Mi-R
2
2
ep
i
alk
c
A. lanceolata var. elliptica Cleve, 1891
eMi-R
2
2
ep
i
alk
c
A. oe strupii (Cleve-Euler)Hustedt, 1930
Pl-R
2
ep
i
i
n-a
Achnanthes sp.1
2
Achnanthes sp.2
2
Eunotia arcus Ehrenberg, 1837
Mi-R
2
ep
hb
ac
n-a
E. bilunaris /Ehr./Mills, 1934
R
3
ep
c
E. faba Ehrenberg, 1838
eMi-R
3
ep
hb
ac
c
E. glacialis Meister, 1912
Mi-R
3
3
3
2
ep
hb
ac
c
E. pe ctinalis var. minor /Kütz./Rabenhorst, 1864
lMi-R
3
4
2
3
2
2
2
ep
hb
ac
c
E. pe ctinalis var. minor f. impressa /Ehr./Hustedt, 1930
Mi-R
2
hb
E. polyglyphoides Sheshukova, 1962
N
3
2
E. praerupta Ehrenberg, 1843
Mi-R
4
5
3
3
3
5
2
ep
hb
ac
c
E. ps eudopectinalis Hustedt, 1924
R
2
ep
n-a
Actinella bras iliensis Grunow , 1881
Mi - R
2
ep
i
tr
Rhoicosphenia abbreviata (Ag.) Lange-Bertalot, 1980
Mi-R
3
3
5
ep
i
alk
c
Cymbella aspe ra /Ehr./Peragallo, 1849
eMi-R
3
4
3
4
2
ep
i
alk
c
C. cistula /Ehr./Kirchner, 1878
Ol-R
2
4
2
2
ep
i
alk
c
C. cistula var. hebetata /Pant./ Cleve-Euler, 1955
Q-R
2
4
C. cuspidata Kützing, 1844
eMi-R
3
2
3
3
2
3
3
ep
i
i
c
C. cymbiform is Agardh,1830
Mi-R
3
ep
i
alk
c
C. cymbiform is var. nonpunctata Fontell, 1917
Mi-R
3
ep
i
c
C. ehrenbergii Kützing, 1844
Mi-R
2
2
3
3
3
2
ep
i albnt
b
C. elginens is Krammer, 1981
Mi-R
4
5
2
3
2
5
2
3
3
3
ep
i
i
c
C. gracilis /Ehr./Kützing, 1844
Plei-R
2
4
3
3
4
3
ep
i
alk
c
C. he lve tica Kützing, 1844
Mi - R
3
3
ep
i
i
c
C. he lve tica va r. curta Cleve, 1894
Q-R
2
ep
i
alk
b
C. huste dtii Krasske, 1925
Mi-R
3
3
3
ep
i
i
c
C. hybrida Grunow, 1878
R
2
ep
i albnt n-a
C. lance olata /Ehr./Kirchner, 1878
eMi-R
2
ep
i
alk
c
C. naviculiform is /Auersw./Cleve, 1894
lMi-R
3
3
3
3
3
3
3
2
ep
i
i
c
C. obtus a Pantocsek, 1892
lMi
3
C. pe rpus illa A.Cleve, 1895
R
2
ac
c
C. silesiaca Bleisch, 1864
eMi-R
3
4
3
3
2
3
3
2
2
3
ep
i
i
c
C. subcuspidata Krammer, 1982
Pl-R
3
3
3
3
3
ep
i
alk
n-a
C. tynni Krammer, 1985
R
2
ep
n-a
Cym bella sp. 1
5
2
5
Cym bella sp. 2
2
Reimeria sinuata f. antiqua /Grun./ Koc.& Stoermer, 1987
lMi-Q
2
2
Amphora bornetti Heribaud,1903
Mi
3
3
3
A. de lphinea A. Schmidt var. jamalinensis /Cl. et Grun./ Cleve, 1895
Pl-R
3
2
A. libyca Ehrenberg, 1840
Mi-R
2
2
3
3
3
3
2
3
3
2
ep
i
alk
c
A. ovalis /Kützing/ Kützing, 1844
Mi-R
2
ep
i
alk
c
A. pe diculus (Kütz.) Grunow, 1880
Mi-R
3
ep
i
alk
c
A. proteus Gregory, 1857
Q-R
2
ep mhb
c
Am phora sp. 1
2
Gomphonema acuminatum Ehrenberg, 1832
Mi-R
3
ep
i
alk
c
G. angustum Agardh, 1831
R
2
ep
i
alk
b
G. augur Ehrenberg, 1843
Mi-R
3
4
3
3
2
3
3
3
3
ep
i
i
c
G. clavatum Ehrenberg, 1832
R
3
3
4
2
d
i
c
G. gracile var. lanceolata (Kütz.) Cleve, 1894
ePl-R
3
ep
i
alk
c
G. grovei var. herrmanniana /Patrik/ Kociolec, J ang, Stoermer, 1988
Mi-R
4
3
G. olivaceum (Horn.) Brebisson, 1838
Mi-R
2
2
ep
i albnt
c
358 OGNJANOVA-RUMENOVA
and VASS
The well VPA-3, Pinciná was represented by two sam-
ples with a very long range: 24.50 m and 37.60 m. The
determined two diatom assemblages (not illustrated) are
not principally different from these described in the se-
quence of VPA-1, Pinciná. The diatom association de-
scribed for level 37.60 m corresponds to the first diatom
assemblage of VPA-1; that for level 24.50 mto the sec-
ond diatom assemblage of VPA-1.
€
The investigated flora from Jelovec and Pinciná de-
posits have a group of common species which allows
correlation 77 species, varieties and formae (42.5 %).
The species composition of the diatom flora of VJA-2,
Jelovec is relatively poor, but the character of the two
diatom assemblages developed in the sequence is similar
to that described for VPA-1, Pinciná. The occurrence of
Cyclotella sp. shows some peculiarities in depth. At the
level of 17.1013.10 m this species is rock-forming and
dominant with some epiphytic accompanying species:
Fragilaria construens f. venter Hust., Rhoicosphenia
abbreviata (Ag.) Lange-Bert., Epithemia zebra var. por-
cellus (Kütz.) Grun, E. turgida (Ehr.) Kütz. and Rhopal-
odia gibba (Ehr.) O.Mull. At 11.10 m Cyclotella sp. dis-
appears and an association with Stephanodiscus
minutulus (Kütz.) Cl. & Molder and mass occurrence of
Aulacoseira species is established. In this seam the
planktonic species Asterionella ralfsii W.Sm. is domi-
nant, too. Some of the accompanying species in the sec-
ond association from VPA-1,2 PincináPliocaenicus
Plate I: Fig. 1. Cyclotella sp., VJA-2 Jelovec, 13.10
€
m,
×
2000. Fig.
€
2. Cyclotella sp., VJA-2 Jelovec, 6.50
€
m,
×
2000. Fig.
€
3. Cyclotella sp.,
VJA-2 Jelovec, 13.10
€
m,
×
2000. Fig.
€
4. Stephanodiscus minutulus (Kütz.) Cl. & Mold., VPA-1 Pinciná, 13.20
€
m,
×
2000. Fig. 5. Aula-
coseira valida (Grun.) Krammer, VPA-1 Pinciná, 10.00
€
m,
×
800. Fig.
€
6. A. valida (Grun.) Krammer, VPA-1 Pinciná, 10.00 m,
×
800.
Fig.
€
7. A. distans var. scala (Ehr.) nov.comb., VPA-1 Pinciná, 5.90
€
m,
×
2000. Fig. 8. A. distans var. scala (Ehr.) nov.comb., VPA-1
Pinciná, 5.90
€
m,
×
800. Fig. 9. A. distans var. scala (Ehr.) nov.comb., VPA-1 Pinciná, 5.90
€
m,
×
2000. Fig. 10. A. ambigua (Grun.) Sim.,
VJA-2 Jelovec, 11.10
€
m,
×
800. Fig. 11. A. granulata (Ehr.) Sim., VPA-1 Pinciná, 13.20
€
m,
×
800. Fig. 12. A. granulata (Ehr.) Sim., VPA-
1 Pinciná, 13.20
€
m,
×
800. Fig. 13. Asterionella ralfsii W.S., VJA-2 Jelovec, 11.10
€
m,
×
800. Fig. 14. Tabellaria sp. VPA-1 Pinciná, 10.00
m,
×
800. Fig.
€
15. Tabellaria sp. VPA-1 Pinciná, 10.00 m,
×
800. Fig. 16. Fragilaria construens (Ehr.) Grun., VPA-1 Pinciná, 13.20 m,
×
2000. Fig. 17. F. construens f. binodis (Ehr.) Hust., VPA-1 Pinciná, 13.20 m,
×
2000. Fig. 18. F. transylvanica Pant., VPA-1 Pinciná,
13.20 m,
×
800. Fig. 19. F. leptostauron (Ehr.) Hust., VPA-1 Pinciná, 13.20 m,
×
800. Fig. 20. F. martyi (Herib.) L.-Bert., VPA-1 Pinciná,
10.00 m,
×
800. Fig. 21. Tetracyclus glans (Ehr.) Mills, VPA-1 Pinciná, 5.90 m,
×
800. Fig. Fig. 22. T. glans (Ehr.) Mills, VPA-1 Pinciná,
5.90 m,
×
800. Fig. 23. T. glans (Ehr.) Mills (septum), VPA-1 Pinciná, 10.00 m,
×
800. Fig. 24. T. emarginatus (Ehr.) W.Sm., VPA-1
Pinciná, 5.90 m,
×
800. Fig. 25. T. emarginatus (Ehr.) W.Sm. (septum), VJA-2 Jelovec, 11.10 m,
×
800. Fig. 26. T. stellare Herib., VPA-1
Pinciná, 13.20 m,
×
800.
DIATOMS
R ANGE
VPA-1 Pinciná
VPA-3
Pinciná VJ A-2 J elovec
Ecology
5.90-6.00m
10.00-10.10m
13.20m
18.30m
26.30m
24.50m
37.60m
.6.50-7.00m
11.10m
13.10m.
17.10m
habitat
halobity
pH
geographical
distribution
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
G. olivace um var. calcareum (Cleve) Cleve, 1894
Pl-R
2
ep
i
alk
b
G. olivace um var. minutissima Hustedt, 1930
Pl-R
3
ep
i
alk
b
G. s ubtile Ehrenberg, 1843
N-R
3
ep
hb
ac
c
G. truncatum Ehrenberg, 1832
Pl-R
3
3
3
3
ep
i
alk
b
Epithe m ia s ore x Kützing, 1844
Mi-R
2
2
2
3
3
2
ep
i albnt
c
E. turgida /Ehr./Kützing, 1844
Mi-R
2
2
2
2
3
3
4
ep
i albnt
c
E. turgida var. granulata (Ehr.) Brun, 1880
Ol-R
3
3
3
ep
i albnt
c
E. ze bra /Ehr./Kützing, 1844
Mi-R
3
ep
i albnt
c
E. ze bra var. porcellus /Kütz./Grunow, 1862
Mi-R
3
4
4
3
3
4
3
3
3
5
ep
i albnt
c
E. ze bra var. saxonica /Kütz./Grunow, 1862
ePl-R
2
3
3
3
4
ep
i albnt
c
Rhopalodia gibba /Ehr./O.Muller, 1895
Mi-R
3
3
3
3
3
3
3
4
4
5
ep
i
alk
c
Nitzschia acuta Hantzsch, 1880
Pl-R
2
d
i
alk
c
N. s inuata var. tabellaria Grunow, 1881
Pl-R
2
d
i
alk
c
Hantzschia amphioxys /Ehr./Grunow, 1880
Mi-R
2
2
2
2
2
2
3
2
2
ep
i
i
c
H. am phyoxis var. capitata Pantocsek, 1902
R
2
Surirella bifrons Ehrenberg, 1843
Mi -R
2
2
d
i
i
b
S. bis e riata Brebissonii, 1836
Mi-R
2
2
3
2
2
ep
i
alk
c
S. bis e riata f. punctata /Meister/Krasske, 1925
Pl - R
+
+
Cymatopleura elliptica /Breb./W . Smith, 1851
Mi-R
2
2
d
i
alk
b
C. s ole a /Breb./W .Smith, 1851
Mi -R
2
3
3
3
2
3
3
3
ep
i
alk
c
Cym atople ura s p.
2
Campylodiscus hibernicus Ehrenberg, 1845
Pl-R
2
2
d
i
alk
b
C. lacus baicali Skvortzow, 1937
Hol-R
2
3
i
i
b
I
PALEOECOLOGY OF THE LATE MIOCENE MAAR LAKES 359
360 OGNJANOVA-RUMENOVA
and VASS
(O.Mull.) Sim. and A. distans var. scala (Ehr.,
nov.comb.) only A. granulata (Ehr.) Sim. is rarely
represented.
Ecological analysis of the diatom flora
The objective of this part of the study is to provide
information concerning the response of diatoms to
different ecological parameters in order to recon-
struct the past environment. Many of the taxa in the
analysed diatom flora are common and widespread
in modern temperate freshwater environments (81.77
%). Only 10 species, varieties and formae have an
unknown ecology. The analysis of the ecological
spectra shows (Fig. 4):
The Halobion spectrum: Species with oligohalobious
habitat form up to 97.9 %. Mesohalobious species such
as Caloneis silicula var. kjellmaniana (Grun.) Cl. and
Amphora proteus Greg. are rare, except for Navicula
digitoradiata (Greg.) Ralfs which is present as a sub-
dominant. The changes in the percentage correlation of
the halobious groups in depth are presented on Figs. 5B,
6B. The quantitative proportions of these groups are al-
most constant and the indifferent species predominate.
According to Habitat spectrum 94.2 % of the dia-
tom flora is benthic. The epiphytic species are more
dominant (62.1 %) than the relatively lower percentage
of deep water form (32.1 %). Typical planktonic spe-
cies such as Stephanodiscus minutulus (Kütz.) Cl. &
Moller, Aulacoseira ambigua (Grun.) Sim., A. granula-
ta (Ehr.) Sim., A. valida (Grun.) Kramm., Asterionella
ralfsii W.Sm. are abundant in depth. The variations in
the percentage ratio of habitat groups are comparatively
the same in both bore-holes: VPA-1 and VJA-2 (Figs.
5C, 6C). At the base of the bore-holes the epiphytic
species are present in large numbers, but in the upper-
most part the benthic (deep water) forms occur with in-
creasing abundance.
In terms of the active water reaction the alkaliphilic
(50 %) and indifferent (26.1 %) species prevail in the di-
atom flora. The acidophilic species amount to only 10.5
%, but some of them such as: Eunotia pectinalis var. mi-
nor (Kütz.) Rabenh., E. praerupta Ehr., Pinnularia inter-
rupta W.Sm., Tetracyclus glans (Ehr.) Mills have been
established in large quantities (Figs. 5A, 6A).
In geographical distribution the cosmopolitan group
(74 %) is predominant, followed by boreals (15 %),
north-alpines (10.3 %) with the tropicals (0.7 %) com-
ing last.
Results of the relative proportions of diatom
frustules/chrysophycean stomatocystae
In the alginite from the well VPA-1, Pinciná tracing
the ratio, diatom frustules/chrysophycean stomatocys-
tae we observed one peak in the development of the
stomatocystae (Fig. 5D). From 26.3013.20 m a diatom
Fig. 7. Sketch of the bore-holes VPA-1 and VPA-3, maar of Pinciná. Ex-
planation: 1 soil, 2 clay/loam, 3 diatomite, 4 silt/siltstone, 5
alginite, 6 tuffaceous sand/sandstone, 7 conglomerate, 8
lapilli and asch tuff, 9 basalt tuff, 10 tuffaceous clay, 11 sand
tuff with basalt fragments, 12 pumice tuff, 13 angular rock frag-
ments, 14 samples.
omarensis (Kütz.) Round & Hak. and Tabellaria sp. are miss-
ing here or occur occasionally. At 6.50 m Cyclotella sp. ap-
pears again in mass. In these deposits subdominants are Gom-
phonema grovei var. herrmanniana (Patr.) Koc. Yang. Stoerm.
and Fragilaria martyi (Herib.) L.-Bert., etc. The development
of Aulacoseira species significantly decreases (A. ambigua
PALEOECOLOGY OF THE LATE MIOCENE MAAR LAKES 361
Fig. 8. Sketch of the bore-hole VJA-2, maar Jelovec. For expla-
nation see Fig. 7.
Plate II: Fig. 1. Navicula digitoradiata (Greg.) Ralfs, VPA-1
Pinciná, 10.00 m,
×
800. Fig. 2. N. tuscula Ehr., VPA-1 Pinciná,
10.00 m,
×
800. Fig. 3. N. menisculus Schum., VPA-1 Pinciná,
10.00 m,
×
800. Fig. 4. N. pseudoanglica L.-Bert., VPA-1 Pinciná,
10.00 m,
×
800. Fig. 5. N. costulata Grun., VPA-1 Pinciná, 13.20 m,
×
800. Fig. 6. Sellaphora bacillum (Ehr.) Mann, VPA-1 Pinciná,
18.30 m,
×
800. Fig. 7. Neidium productum (W.Sm.) Cl., VPA-1
Pinciná, 13.20 m,
×
800. Fig. 8. Stauroneis phoenicenteron
(Nitzsch.) Ehr., VPA-1 Pinciná, 10.00 m,
×
800. Fig. 9. S. smithii
var. incisa Pant., VJA-2 Jelovec, 13.10 m,
×
800. Fig. 10. Pinnular-
ia braunii var. amphicephala (Mayer Hust., VPA-1 Pinciná,
10.00 m,
×
800. Fig. 11. P. interrupta W.Sm., VPA-1 Pinciná,
10.00 m,
×
800. Fig. 12. P. maior (Kütz.) Rabenh., VPA-1 Pinciná,
10.00 m,
×
800. Fig. 13. P. esox Ehr., VPA-1 Pinciná, 10.00 m,
×
800.
Fig. 14. Achnanthes flexella (Kütz.) Brun., VPA-1 Pinciná, 5.90 m,
×
800. Fig. 15. Achnanthes sp., VPA-1 Pinciná, 10.00 m,
×
800. Fig.
16. Diploneis elliptica (Kütz.) Cl., VPA-1 Pinciná, 13.20 m,
×
800.
Fig. 17. D. elliptica (Kütz.) Cl., VPA-1 Pinciná, 13.20 m,
×
800. Fig.
18. Cymbella gracilis (Ehr.) Kütz., VPA-1 Pinciná, 10.00 m,
×
800.
Fig. 19. C. silesiaca Bleisch., VPA-1 Pinciná, 10.00 m,
×
800. Fig.
20. C. naviculiformis (Auersw.) Cl., VPA-1 Pinciná, 13.20 m,
×
800.
Fig. 21. C. ehrenbergii Kütz., VJA-2 Jelovec, 13.10 m,
×
800. Fig.
22. C. subcuspidata Kramm., VPA-1 Pinciná, 10.00 m,
×
800. Fig.
23. C. aspera (Ehr.) Perag., VPA-1 Pinciná, 10.00 m,
×
800.
Plate III: Fig. 1. Eunotia pseudopectinalis Hust., VPA-1 Pinciná,
10.00
€
m,
×
800. Fig. 2. E. pectinalis var. minor (Kütz.) Rabenh.,
VPA-1 Pinciná, 10.00
€
m,
×
800. Fig. 3. E. praerupta Ehr., VPA-1
Pinciná, 10.00
€
m,
×
800. Fig.
€
4. E. praerupta Ehr., VPA-1 Pinciná,
10.00
€
m,
×
800. Fig.
€
5. E. polyglyphoides Sheshuk., VJA-2 Jel-
ovec, 6.50
€
m,
×
800. Fig. 6. Gomphonema acuminatum Ehr., VPA-
1 Pinciná, 10.00
€
m,
×
800. Fig. 7. G. gracile var. lanceolata
(Kütz.) Cl., VPA-1 Pinciná, 10.00
€
m,
×
800. Fig. 8. G. clavatum
Ehr., VPA-1 Pinciná, 10.00
€
m,
×
800. Fig. 9. G. grovei var. her-
rmanniana (Patr.) Koc., Yang, Stoerm., VJA-2 Jelovec, 11.10
€
m,
×
2000. Fig. 10. Epithemia turgida (Ehr.) Kütz., VPA-1 Pinciná,
13.20
€
m,
×
800. Fig. 11. E. zebra var. saxonica (Kütz.) Grun.,
VPA-1 Pinciná, 10.00
€
m,
×
800. Fig. 12. E. zebra var. porcellus
(Kütz.) Grun., VPA-1 Pinciná, 10.00
€
m,
×
800. Fig.
€
13. E. sorex
Kütz., VJA-2 Jelovec, 11.10
€
m,
×
800. Fig.
€
14. Rhopalodia gibba
(Ehr.) O.Mull., VJA-2 Jelovec, 11.10
€
m,
×
800. Fig. 15. R. gibba
(Ehr.) O.Mull., VPA-1 Pinciná, 5.90
€
m,
×
800. Fig. 16. Surirella
biseriata Breb., VPA-1 Pinciná, 13.20
€
m,
×
800. Fig. 17. Cy-
matopleura solea (Breb.) W.Sm., VJA-2 Jelovec, 11.10
€
m,
×
800.
Fig. 18. Campylodiscus lacus baicali Skw., VPA-1 Pinciná,
10.00
€
m,
×
800. Fig.
€
19. Hantzschia amphioxys (Ehr.) Grun., VPA-
1 Pinciná, 5.90
€
m,
×
800. Figs.
€
20,
€
21,
€
23. Chrysophycean stoma-
tocystae, VPA-1 Pinciná, 10.00 m,
×
800. Figs. 22, 24, 25. Chryso-
phycean stomatocystae, VPA-1 Pinciná, 5.90
€
m,
×
800.
association with monospecific character is established.
Within this range the relative proportion in the algal
successions is comparatively constant (varies between
89 and 100 % with the diatom predominating). The ratio
in the sample at 10.0 m is different. The quantity of the
chrysophycean stomatocystae sharply increases and this
coincides with a change in the diatom succession the
second diatom assemblage has developed. Different species
of the genus Aulacoseira Thw. and also Stephanodiscus
minutulus (Kütz.) Cl. & Moll. are found indicating an
eutrophic environment of the paleolake.
In the diatomite from the well VJA-2, Jelovec the ratio di-
atom frustules/chrysophycean stomatocystae in the examined
core-drill is relatively constant (Fig. 6D). At 11.10 m there is
insignificant increase in the quantity of the stomatocystae.
This coincides with the appearance and abundant develop-
ment of the typical eutrophic speciesStephanodiscus
minutulus (Kütz.) Cl. & Mold., Aulacoseira ambigua
(O.Mull.) Sim. In the uppermost part of the borehole the dia-
toms are dominant (92100 %). The quantity of Cyclotella
sp. is increasing again and supports the development of a
new oligotrophic stage.
Paleoecological interpretation and conclusion
The ecological analysis of siliceous microfossils (dia-
tom and chrysophycean stomatocystae) gives evidence
that the maar sediments of Podreèany Basalt Formation
were probably deposited in a comparatively shallow
lacustrine environment. The waters of the lake were
slightly alkaline (pH = 78) with salinity of (0.2) 0.30.5
. The climate was temperate. The lake grew progressive-
ly shallower because of filling with sediments and in-
crease of the plankton production. The nutrient spectrum
suggests that in the beginning of the deposition an olig-
I
362 PLATE II
PLATE III 363
364 OGNJANOVA-RUMENOVA
and VASS
Plate IV: Fig. 1. Aulacoseira distans var. scala (Ehr.) nov.comb. and chrysophycean stomatocystae, VPA-1, Pinciná, 5.90 m, SEM,
×
4000. Fig. 2. Aulacoseira distans var. scala (Ehr.) nov.comb.VPA-1, Pinciná, 5.90 m, SEM,
×
10,000. Fig. 3. Aulacoseira distans var.
scala (Ehr.) nov.comb.VPA-1, Pinciná, 5.90 m, SEM,
×
7200. Fig. 4. Aulacoseira distans var. scala (Ehr.) nov.comb.VPA-1,
Pinciná, 5.90 m, SEM,
×
10,000.
PALEOECOLOGY OF THE LATE MIOCENE MAAR LAKES 365
Plate V: Fig. 1. The rock-forming Cyclotella sp., VJA-2 Jelovec, 13.10 m, SEM,
×
1000. Fig. 2. Cyclotella sp., valve exterior, VJA-2 Jel-
ovec, 13.10 m, SEM,
×
7200. Fig. 3. Cyclotella sp., valve exterior, VJA-2 Jelovec, 13.10 m, SEM,
×
6000. Fig. 4. Cyclotella sp., valve exte-
rior, VPA-1 Pinciná, 18.30 m, SEM,
×
10,000.
366 OGNJANOVA-RUMENOVA
and VASS
Plate VI: Fig. 1. Cyclotella sp., valve exterior, VJA-2 Jelovec, 13.10 m, SEM,
×
10,000. Fig. 2. Cyclotella sp., striae pattern, VPA-1
Pinciná, 18.30 m, SEM,
×
10,000. Fig. 3. Cyclotella sp., valve interior, VJA-2 Jelovec, 13.10 m, SEM,
×
5400. Fig. 4. Cyclotella sp., de-
tail of the valve interior (A-marginal fultoportula with three satelite pores and B-the single rimoportule), VJA-2 Jelovec, 13.10 m, SEM,
×
12,000.
PALEOECOLOGY OF THE LATE MIOCENE MAAR LAKES 367
Plate VII: Fig. 1. Tabellaria sp., valve interior, VPA-1 Pinciná, 5.90 m, SEM,
×
7200. Fig. 2. Tabellaria sp., septum, VPA-1 Pinciná, 5.90 m,
SEM,
×
9400. Fig. 3. Tabellaria sp., septum, VPA-1 Pinciná, 5.90 m, SEM,
×
6600. Fig. 4. Chrysophycean stomatocysta, VPA-1 Pinciná,
5.90 m, SEM,
×
9400.
368 OGNJANOVA-RUMENOVA
and VASS
otrophic phase can be distinguished, which is followed by
a eutrophic stage in both bore-hole sequences (VPA-1
Pinciná and VJA-2 Jelovec). Only in the sedimentation
of VJA-2 Jelovec a probably high influx of water deter-
mined a new oligotrophic stage.
Taking into consideration other ecological indicators
into account, as well as the ecological demand of diatom
assemblages, one can made larger paleoecological inter-
pretations. An oligotrophic phase took place in the Jel-
ovec maar at the beginning of the depositions. In the
Pinciná maar the whole lake fill is crowded by organic
matter of Botryococcus braunii. For preservation of the
organic matter in an excellent state, anaerobic condition
in stagnant water with a stratified water column, are as-
sumed. From the beginning of the deposition, eutrophic
condition are evident. The oligotrophic phase proved by
the diatom assemblage studied from the depth of 13.2
26.3 m (bore-hole VPA-1) must be occasional and not
dominant.
The eutrophic, shallow, stagnant water with pH about 7.6
is assumed also by Hajós (1990) for the lakes in which the al-
ginite was originated in Hungary. Salinity in the Hungarian
maar lakes was higher (3 ) that in the Pinciná maar.
Organic matter is missing from the sedimentary infill of
the Jelovec maar. The deposition could take place in well
oxygenated bottom water. The idea is supported by the Di-
atomaceae assemblages indicating the oligotrophic stage in
both the lower and upper portions of the lake filling sedi-
ments.
Acknowledgements: Project IGCP 329: Palaeogeographic
and palaeoecologic evolution of Paratethys basin during
Neogene and their correlation to the global scales. Project
VEGA No AL 09 1310 1/4032/97 Alginite a new eco-
logical raw material fisibility study.
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