Climate and early karstification: What can be learned by models?
First an overview is given on the present state of modelling of karst aquifers and karst conduits. Emphasis is placed to early karstification in rock massives with low fissure density as suggested for states 1 and 2 in Ford’s four-state-model. In this case early karstification proceeds under the con...
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Faculty of Geology University of Warsaw
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ftjgq:oai:geojournals.pgi.gov.pl:article/10058 2024-09-09T19:27:38+00:00 Climate and early karstification: What can be learned by models? Dreybrodt, Wolfgang Gabrovsek, Franci 2003-09-01 application/pdf https://gq.pgi.gov.pl/agp/article/view/10058 eng eng Faculty of Geology University of Warsaw https://gq.pgi.gov.pl/agp/article/view/10058/8588 https://gq.pgi.gov.pl/agp/article/view/10058 Acta Geologica Polonica; Vol. 52 No. 1 (2002): Climate Changes – The Karst Record; 1-11 Acta Geologica Polonica; Tom 52 Nr 1 (2002): Climate Changes – The Karst Record; 1-11 Karst Early karstification Modelling Climate info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2003 ftjgq 2024-07-30T03:29:09Z First an overview is given on the present state of modelling of karst aquifers and karst conduits. Emphasis is placed to early karstification in rock massives with low fissure density as suggested for states 1 and 2 in Ford’s four-state-model. In this case early karstification proceeds under the condition of a constant hydraulic head. The evolution of a single isolated karst conduit, as well as evolution of karst conduits in two-dimensional networks of fractures are discussed. From these models the parameters determining early karstification can be identified. These are the initial aperture widths of the fractures, their lengths, the hydraulic head, and the viscosity of water, as well as the parameters of the non-linear dissolution kinetics of limestone, and the equilibrium concentration of calcium with respect to calcite. Early karstification under constant head conditions is characterized by a feedback-mechanism which couples flow rates through the conduits to the dissolutional widening of the fracture. After an initially slow increase in flow and in aperture width of the fracture a dramatical increase of flow rates and fracture widening occurs at breakthrough. The breakthrough time, when this event happens can be quantified from the parameters defined above. This time can be considered as a measure of intensity of karstification. Large scale climatic parameters, especially temperature exert influence to breakthrough time. Under otherwise identical geological conditions breakthrough times in tropic and moderate climates are about 5 times shorter than in arctic/alpine climate. Micro-climatic conditions, however, are of similar importance. If the vegetation on a karst plateau exhibits regions with different CO2 partial pressure in the soil, waters from these differing regions may mix at fracture-confluences in the karst massive. Mixing corrosion causes renewed solutional power at these confluences. Therefore breakthrough times can be reduced significantly. We present details of this mechanism and its influence ... Article in Journal/Newspaper Arctic Geological Quarterly Arctic |
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Geological Quarterly |
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English |
topic |
Karst Early karstification Modelling Climate |
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Karst Early karstification Modelling Climate Dreybrodt, Wolfgang Gabrovsek, Franci Climate and early karstification: What can be learned by models? |
topic_facet |
Karst Early karstification Modelling Climate |
description |
First an overview is given on the present state of modelling of karst aquifers and karst conduits. Emphasis is placed to early karstification in rock massives with low fissure density as suggested for states 1 and 2 in Ford’s four-state-model. In this case early karstification proceeds under the condition of a constant hydraulic head. The evolution of a single isolated karst conduit, as well as evolution of karst conduits in two-dimensional networks of fractures are discussed. From these models the parameters determining early karstification can be identified. These are the initial aperture widths of the fractures, their lengths, the hydraulic head, and the viscosity of water, as well as the parameters of the non-linear dissolution kinetics of limestone, and the equilibrium concentration of calcium with respect to calcite. Early karstification under constant head conditions is characterized by a feedback-mechanism which couples flow rates through the conduits to the dissolutional widening of the fracture. After an initially slow increase in flow and in aperture width of the fracture a dramatical increase of flow rates and fracture widening occurs at breakthrough. The breakthrough time, when this event happens can be quantified from the parameters defined above. This time can be considered as a measure of intensity of karstification. Large scale climatic parameters, especially temperature exert influence to breakthrough time. Under otherwise identical geological conditions breakthrough times in tropic and moderate climates are about 5 times shorter than in arctic/alpine climate. Micro-climatic conditions, however, are of similar importance. If the vegetation on a karst plateau exhibits regions with different CO2 partial pressure in the soil, waters from these differing regions may mix at fracture-confluences in the karst massive. Mixing corrosion causes renewed solutional power at these confluences. Therefore breakthrough times can be reduced significantly. We present details of this mechanism and its influence ... |
format |
Article in Journal/Newspaper |
author |
Dreybrodt, Wolfgang Gabrovsek, Franci |
author_facet |
Dreybrodt, Wolfgang Gabrovsek, Franci |
author_sort |
Dreybrodt, Wolfgang |
title |
Climate and early karstification: What can be learned by models? |
title_short |
Climate and early karstification: What can be learned by models? |
title_full |
Climate and early karstification: What can be learned by models? |
title_fullStr |
Climate and early karstification: What can be learned by models? |
title_full_unstemmed |
Climate and early karstification: What can be learned by models? |
title_sort |
climate and early karstification: what can be learned by models? |
publisher |
Faculty of Geology University of Warsaw |
publishDate |
2003 |
url |
https://gq.pgi.gov.pl/agp/article/view/10058 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Acta Geologica Polonica; Vol. 52 No. 1 (2002): Climate Changes – The Karst Record; 1-11 Acta Geologica Polonica; Tom 52 Nr 1 (2002): Climate Changes – The Karst Record; 1-11 |
op_relation |
https://gq.pgi.gov.pl/agp/article/view/10058/8588 https://gq.pgi.gov.pl/agp/article/view/10058 |
_version_ |
1809897038335180800 |