18
treatment of negatives and positives, season of the year and
time of day when the photo was taken, as well as environmental
factors such relief, hydrographic network, presence of vegetation
and buildings.
Geological photointerpretation of the investigated area
supplied a lot of informations. We can find there e.g. that massive
rocks like sandstones built peaks and ridges, more soft
rocks, like shale or shale-sandstone complexes build the valleys.
When stratification is marked we can interpret fold structures
and find faults that cut the structure. It is possible to indicate
same intersection lines, the boundaries of lithological
complexes or thrust lines. In the investigated area the overthrust
of the Magura Nape is especially well visible. It is possible
to distinguish also fluvial terraces, landslides, bedding of
rocks and to separate Quaternary deposits from their older
basement. The photointerpretation performed in this way led to
geological sketch of the investigated area.
Verification of this material is possible by comparison of
the photointerpretative sketch with a geological map. The differences
in location of given elements on the two maps are determined
by several factors: the way of the map preparation,
misplacement of an element on the geological map and difficulties
with an interpretation on the areas covered by abundant
vegetation.
Ostaficzuk S. 1978 Fotogeologia. Fotointerpretacja i fotogrametria
geologiczna Wydawnictwa Geologiczne, Warszawa
Biogeochemical role of microorganisms in the
formation of carbonate microbialites: a review
Agnieszka GÓJSKA, Dorota WOLICKA
Institute of Geochemistry, Mineralogy and Petrology, Faculty of
Geology, University of Warsaw, Poland; a.gojska@student.uw.
edu.pl; d.wolicka@uw.edu.pl
Microorganisms are the oldest life forms on Earth. The
current shape and composition of the oxidizing atmosphere is
the result of over three billion years of the activity of living organisms
that continue to shape and modify it (Tice 2008).
Biogenic rocks called microbialites are evidence of the activity
of microorganisms living in remote geological ages. The
formation of these carbonate structures is linked with the
emergence of metabolic processes carried out by symbiotic microorganisms
living in consortia. As a result, microbial mats
are produced. They are often characteristic of extreme environments,
such as hypersaline water reservoirs, acid lakes, hot
springs or extremely cold Antarctic area (Chafetz & Buczynski
1992).
Life and development in extreme conditions depend on
close physiological relationships between organisms that form
part of the mat structure. The microbial structure is characterized
by stratification of “sub-environments”, which are inhabited
by microorganisms typical of the physico-chemical conditions
within each level. The presence of zones with particular
groups of microorganisms in the mat succession is associated
with variable redox potential. Photosynthetic cyanobacteria
develop in the subsurface oxic zone with direct access to sunlight.
Among the group of anaerobic organisms that build the
microbial mat-type structure are bacteria that reduce sulfates
in anaerobic conditions (SRB) and phototropic bacteria oxidizing
sulfur compounds (Dupraz, Visscher 2005).
One of the major groups of anaerobic bacteria significant
for many geological processes are sulfate-reducing bacteria.
They participate in nearly all processes of mineral and rock formation.
They can take an active part in precipitation of calcium
carbonate, which is responsible for the lithification of microbial
mats. These heterotrophic organisms induce formation of carbonates
through the production of HCO3
as
a result of mineralization
of organic compounds, which they use as the carbon
source (Wolicka, Borkowski 2008):
If calcium ions are present in sufficient quantities in the
environment, and there are optimal physical and chemical factors
such as pH, concentration of organic compounds and the
presence of crystallization nuclei, this can lead to precipitation
of calcium carbonate. Carbonate minerals such as calcite and
dolomite are found in environments typical of SRB and in conditions
favoring sulfate reduction. Precipitation of calcium carbonate
and consequently lithification of microbial mats favor
the development of microbialites. Carbonates play the role of
specific cement thus creating an opportunity to preserve these
deposits even in high-energy environments (Tice 2008).
Chafetz, H. S., Buczynski, C. 1992 Bacterially induced lithification
of microbial mats. Palaios 7: 277-293
Dupraz, C. , Visscher, P. T. 2005 Microbial lithification in marine
stromatolites and hypersaline mats. Trends in Microbiology
13: 429-438
Tice, M. 2008 Palaeontology: Modern life in ancient mats. Nature
452: 40-41
Wolicka, D., Borkowski, A. 2008 Participation of sulphate reducing
bacteria in formation of carbonates, Geobiology of stromatolites,
International Kalkowsky-Symposium, Gőttingen:
130-131
Comprehensive assessment of the main factors
of landslide processes formation
and activation in Carpathian region
Oksana GUDA
Department of General and Historical Geology, Geological Faculty,
Taras Shevchenko National University of Kyiv, Ukraine;
Oksana_Guda@mail.ru
Permanent activation of landslide phenomenon in the
Carpathian region and their negative impact on technological
systems increasingly requires a deep understanding of their
origin and genetic features. It is important to determine the
complex of interactions between factors, which influence their
formation, especially in areas of intensive disintegration of the
flyschoid complex. A special difficulty is the formation of structural
landslides within the zones that have acquired extensive
development in Carpathian region.
Carpathian model polygon was used for studying the dynamics
of formation and activation of hazardous landslide processes.
Geological explorations were done in Svalyavskiy, Volovetskiy
and Irshavskiy regions of the Zakarpatska area. The
detailed analysis of the field data allows to select the main factors
of landslides’ activation. They are: geomorphologic, landscape-climatic,
lithologic and stratigraphic, meteorological,
neotectonic, seismic and structural-tectonic.
Carpathian polygon has a complicated heterogeneous
geological structure. It consists of complexes of sedimentary,
volcanic and unconsolidated sediments of Jurassic, Cretaceous,
Palaeogene, Neogene and Quaternary age. It should be
noted that flyschoid formation prevails among the sedimen-
SO
2+
organic compound → HS-+H2
O+HCO-
4 3
SRB