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| Titel |
Groundwater Coastal Discharge at the Kalogrias Bay in Mani and its Relationship with the Geological and Tectonic Structure of Taygetos (Mani, Southern Peloponnese- Greece) |
| VerfasserIn |
George Migiros, Ioannis Papanikolaou |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250043846
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| Zusammenfassung |
| A massive groundwater coastal gushing spring with an annual freshwater discharge rate that
exceeds 7*106m3 has been mapped within the Messiniakos Gulf in the Kalogrias bay and
Kardamili-Mani (southern Peloponnese), approximately 100m from the coastline. The
mechanism that supports this high discharge rate is not only of exceptional scientific interest
due also to its complexity, but its potential exploration would be crucial for the future
survival, economic development and prosperity of a large part of the Mani peninsula. The sea
bottom morphology has an ovoid shape with the deepest part at 29m towards the gushing
spring, it is characterized by important linear morphologic features in a rather unstable
geologic environment of carbonate bedrock which is covered by a thin layer of semi-cohesive
sediments. The study area belongs to the Geotectonic Unit of Mani that covers
a large part of the Taygetos mountain and forms the predominant water supply
source for all karstic springs of Mani. It consists of thick carbonates of Triassic that
end up with the flysch sedimentation in Oligocene times. These alpine rocks are
covered uncomfortably by Pliocene and Pleistocene sediments of variable clastic
materials.
Detailed geological and tectonic analysis of the region, supported by the mapping of
springs and the relevant karstic features of the area shows that:
a) Springs towards the mountain areas are either contact springs or karstic springs of low
discharge rate that are strictly related to the folds and thrusts that were developed during the
Alpine deformation phase.
b) Springs towards lower slopes and the lowland areas are linked to the Pliocene and
Pleistocene sediments that outcrop in local topographic lows and are aligned along
strike the normal faults formed by the subsequent extensional phases. They are of
low discharge rate and their water supply comes both from the overlying strata
of the same Plio-Pleistocene deposits and sideways from the bedrock carbonate
rocks.
c) All springs that are developed towards the lowland areas, the shoreline and
predominantly offshore, where the major gushing spring of Kalogrias bay emerge, are
directly related to the karstic hydrological pattern of the Taygetos Mountain.
This karstic path is highly related to the tectonic structures and in particular:
a) towards the mountain area it follows the anticline megastructures with a N-S trending
fold axis that is plunging towards south;
b) towards the hilly area and the lower slopes it strikes west following the transverse fault
structures that form oblique normal faults that are E-W trending;
c) towards the lowland, shoreline and offshore area the karstic water produces gushing
springs along strike the NNW-SSE trending normal faults that were formed during the recent
extensional field and predominantly towards their intersection points with the transverse E-W
trending oblique normal faults.
In conclusion, these pathways that are tectonically controlled, are used by the karstic
systems that have been mapped and discharge the karstic water flow westwards towards the
Messiniakos Gulf. |
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