Middle Miocene palynoflora of the Legnica lignite deposit complex ...

Cookson, Phragmothyrites Edwards, Plochmopeltinites
Cookson, and Trichothyrites
Rosendahl emend. Smith = Notothyrites Cookson)
were found.
The Microthyriaceae fungi are usually
ectoparasites extended in tropical and subtropical
regions. Their presence is an important
index of high total annual rainfall – above
1000 mm. They usually live on leaves of seed
plants (Betulaceae, conifers and others) and
ferns – Pteridium, Aspidum and others (Neuy-
Stolz 1958, Elsik 1978). According to Elsik (op.
cit.) they occur in deposits since the Lower Cretaceous,
but the most numerous are Eocene
and Miocene localities.
ABRIDGED DESCRIPTION
OF POLLEN DIAGRAMS
The results of palynological investigations
are presented in three pollen diagrams (Figs
3–5) constructed using the POLPAL computer
program (Nalepka & Walanus 2003). The percentage
values are based on the total sum of
pollen grains and spores. Most taxa have their
own columns. However, some columns present
a sum of a few taxa (two or more genera, one
family or two families). The sporomorphs are
arranged in the diagrams according to plant
communities from mesophytic to wet. Herbs,
pteridophytes and mosses are presented separately
at the end of the histograms.
The pollen diagrams have been divided into
four sections (L1–L4), containing samples with
similar frequency of thermophilous taxa.
LUSATIAN SEAM
This part (section L1) contains samples
from the profi le Legnica 33/56 from the depth
112.0–100.5 m (Nos 46–24) as well as Legnica
41/52 – depth 125.5–114.4 m (Nos. 43–20),
taken mainly from brown coal. The bottom
samples of both profi les, taken from light-grey
sandy clay, could represent the Silesian-Lusatian
series. However, rather bad preservation
of sporomorphs makes impossible detailed
studies and distinguishing a separate section
for the Silesian-Lusatian series.
Although the arctotertiary element prevails,
the palaeotropical taxa play an important
role (Tab. 1), and are represented mainly
by Tricolporopollenites pseudocingulum (up to
65
42% of total sum) and Quercoidites henrici (up
to 6%), as well as Momipites punctatus, Castaneoideaepollis
oviformis and C. pusillus (a few
per cent). Pollen grains of palms (Arecipites
pseudoconvexus) are encountered regularly,
whereas Sapotaceae (Tetracolporopollenites
andreanus and T. rotundus) and Meliaceae
occur sporadically. In bottom samples of both
profi les pollen grains of Reevesiapollis triangulus
reach about 2%. Relatively high quantities
of Tricolporopollenites exactus (up to
20%), T. megaexactus (up to 1%), T. fallax (up
to 12%), T. liblarensis (up to 3%), Araliaceaeoipollenites
edmundi, A. euphorii (a few per
cent), Ilexpollenites (I. iliacus, I. marcodurensis
and I. propinquus – together up to 10%), Myricipites
+ Triatrio pollenites rurensis (up to 6%),
Symplocoipollenites vestibulum and S. latiporis
(together up to 2%), as well as Corylopsis type
(up to 1%) are also characteristic features of
this section. Moreover, pollen grains of Nelumbopollenites
europaeus are sporadically found.
Among the arctotertiary taxa the most
numerous are Taxodiaceae/Cupressaceae (Inapertu
ro pollenites – max. 50%), Nyssapollenites
(up to 12%), Alnipollenites verus (a few per
cent), Ericipites (up to 12%; including E. roboreus
up to 2%), Sequoiapollenites (up to 35%),
Pinuspollenites + Cathayapollis (up to 40%),
and Abiespollenites (up to 12%). Pollen grains
of Sciadopityspollenites are encountered regularly.
In addition, in bottom samples Intratriporopollenites
insculptus (present in only one
sample) and Periporopollenites orien taliformis
occur.
Section L1 is characterized also by high frequency
of Sphagnum spores (max. 35%), while
Polypodiaceae s.l. and Osmunda, as well as
spores of Lycopodiaceae and Toroisporis are
found sporadically. In addition, the Microthyriaceae
fungi, fragments of plant tissues as
well as stomata resembling those of the Taxodiaceae
family, and fresh-water phytoplankton
(Ovoidites ligneolus, Tetraporina and Sigmopollis)
were found. In bottom samples of both
Legnica profi les Sigmopollis is very numerous,
and accompanied by single dinofl agellate
cysts.
In the upper part of this section of the profi le
Legnica 33/56 frequency of Cyrillaceae/Clethraceae,
Ericaceae, Ilex, Myrica, and Sequoia distinctly
increases. Moreover, in these samples
the role of mesophilous taxa Tricolporopollenites
pseudocingulum, Araliaceae, Fabaceae,