The study investigated marks of hypogenic karstification in the carbonate aquifer system of Buda Thermal Karst, Hungary. Cavities and mud losses indicating deep karstification were analyzed in 78 water exploration wells and found to occur in all carbonate hydrostratigraphical units, including marls. The connection between cavities and structural elements was detected in some cases but not demonstrable in others. Cavities were found from several meters to 300-350 meters depth and crossed multiple formations, though not both Triassic and Eocene units. Future work will further compare cavity presence to geological logs.

1. Investigation of marks for deep karstification
in the carbonate aquifer system of Buda Thermal Karst
1 1 1
Edina Pável , Judit Mádl-Szőnyi , Anita Erőss
1
Institute of Geography and Earth Sciences, Eötvös Loránd University, Budapest, Hungary
1. Introduction The hypogenic karst systems are presently less known, in which case the
dissolution of carbonates is influenced by deep originated gases, fluids and
energy (Palmer 1991; Klimchouk 2007). The hypogene karsts are typical in the
deep and discharge zones of the intermediate and regional flow systems.
Different mineral precipitates such as pyrite, iron oxide and calcite precipitates
often accompany the cavities in the depth.
One of the type areas of the hypogenic karst systems is the Buda Thermal Karst.
The connection between the phenomena caused by water flows in the caves of
Buda (unconfined karst) is proved and generalized (Erőss 2010; Mádl-Szőnyi and
Erőss, 2013). The question is, what is below the confined karst? Do cavities,
calcite- and iron oxide precipitates occur there too?
Erőss A. (2010): Characterization of fluids and evaluation of their effects on
karst development at the Rózsadomb and Gellért Hill, Buda Thermal Karst,
Hungary. – PhD Dissertation, ELTE, 171p.
Haas J. (szerk.) (2010): A múlt ösvényein. Szemelvények Magyarország
földjének történetéből. – Magyarhoni Földtani Társulat, Budapest, 194 p.
Mádl-Szőnyi J., Erőss A. (2013): Effects of regional groundwater flow on deep
carbonate systems focusing on discharge zones. − Proceedings of the
International Symposium on Regional Groundwater Flow: Theory, Applications
and Future development. 21-23 June Xi'an, China. China Geological Survey,
Commission of Regional Groundwater Flow, IAH, 71-75.
Mindszenty A. (szerk.) (2013): Budapest: Földtani értékek és az ember "In urbe
et pro urbe" (Városgeológiai tanulmányok 2013). − ELTE Eötvös Kiadó,
Budapest, (in press)
Klimchouk A. B. (2007): Hypogene Speleogenesis: Hydrogeological and
Morphogenetic Perspective Special Paper no.1, National Cave and Karst
Research Institute, Carlsbad, NM, 106.
Palmer A. N. (1991): Origin and morphology of limestone caves. − Geological
Society of America Bulletin 103: 1-21.
References
Conclusions
Acknowledgements
2. Research for marks of hypogene
karstification in sequences of water
exploration wells
3. Marks for hypogene karstification in
different carbonate hydrostratigraphical units
It was investigated that are the mud losses and cavities
indicate connection with formations. Thus the mud
losses and cavities found per hydrostratigraphical units
were analyzed on bar charts. It was concluded that
these phenomena can be derived from all carbonate
formations (even from marl).
6 maps were prepared
about the carbonate
hydrostratigraphical
units. It could be
concluded that mud
losses and cavities can
occur in all carbonate
even in marls.
The correlation of the
cavities with structural
elements sometimes
was detected but in
other cases it was not
demonstrable. Cavities
can be observed in
more well logs from the
covered karst compared
to the uncovered karst.
hydrostratigraphical
units,
During the work the marks possibly referring to the
hypogenic karstification were collected and were
inserted to a database to determine that to which
carbonate formations these marks are connected,
and can connection with structural elements be
detected, as well as in what levels these are located
in the sequence. Documentations of 78 water
exploration wells were used which were drilled in
Budapest and its surroundings, and from these 46
were involved in the evaluation. During the
processing it was considered as direct mark for
deep karstification if it was documented in the
carbonate formation, while the mud loss was
concidered as indirect mark. The calcite and iron
sulphide precipitates were also involved in the
evaluation.
On the maps every points indicate a well where it can be detected
cavities directly. Taking into consideration the elevation range of the
cavities along the section great variability was found. The occurrence
of cavities in the wells extends from some meters to 300-350 meters.
In the wells multilevel cavities were found affecting different formations.
However there were no cavities effecting both the Triassic and the
Eocene formations. The exception is the well Diósd K-14 where cavities
occur in Triassic and Miocene formations too.
4. The areal distribution and structural determination of the cavities
Buda Marl AQ
(Geological map: Fodor in Mindszenty ed. 2013 in press)
Dachstein Limestone AQ and Hauptdolomit AQ
(Geological map: Haas ed. 2010)
5. Elevation ranges of cavities
Triassic formations Eocene and Miocene formations
6. Visualization of marks for hypogene karstification
along geological section
(Mádl-Szőnyi and Erőss, 2013)
(Erőss, 2010)
(Geological section: Fodor in Mindszenty ed. (2013) in press)
The evaluation was prepared for the section highlighted
with blue from the geological section of Fodor. It could be
concluded that marks for hypogene karstification appeared
in limestone and dolomite, as well as in 2 wells from 4
calcite- and pyrite precipitations and cavities can be found
in connection with structural elements.
We to Szilvia Simon for her help with use Surfer. Thanks
to the workers of MBFH and MFGI repository. The research was carried out within the
framework and with the support of the OTKA NK 101356 (Supervisor: Judit Mádl-Szőnyi).
would like to express our thanks
Cavities and mud losses can occur in all carbonate hydrostratigraphical units, even in marls
The connection of cavities with structural elements is detected in some cases, in other cases
it is not demonstrable (but it can not excluded). The occurrence of cavities in the wells extends
from some meters to 300-350 meters.In the wells multilevel cavities were found affecting
different formations. However there were no cavities effecting both the Triassic and the Eocene
formations. In the future we would like to investigate the presence of cavities in carbonate
formations of well compared with geological logs.
?
Diós K-14 Diós K-14