Geomorphological study and paleogeographic evolution of NW Kefalonia Island, Greece, concerning the hypothesis of a possible location of the Homeric Ithaca

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Geomorphological study of Cephalonia
Island, Ionian Sea, Western Greece
Efthimios Karymbalis
a
, Dimitrios Papanastassiou
b
, Kalliopi Gaki-
Papanastassiou
c
, Konstantinos Tsanakas
c
& Hampik Maroukian
c
a
Department of Geography, Harokopio University, 70 El. Venizelou
Str, Athens, GR-17671, Greece
b
Institute of Geodynamics, National Observatory of Athens,
Athens, GR-11810, Greece
c
Department of Geography and Climatology, Faculty of Geology
and Geoenvironment, National University of Athens, Athens,
GR-15784, Greece
Version of record first published: 14 Jan 2013.
To cite this article: Efthimios Karymbalis , Dimitrios Papanastassiou , Kalliopi Gaki-Papanastassiou ,
Konstantinos Tsanakas & Hampik Maroukian (2013): Geomorphological study of Cephalonia Island,
Ionian Sea, Western Greece, Journal of Maps, DOI:10.1080/17445647.2012.758423
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SCIENCE
Geomorphological study of Cephalonia Island, Ionian Sea, Western
Greece
Efthimios Karymbalis
a
∗
, Dimitrios Papanastassiou
b
, Kalliopi Gaki-Papanastassiou
c
,
Konstantinos Tsanakas
c
and Hampik Maroukian
c
a
Department of Geography, Harokopio University, 70 El. Venizelou Str, Athens GR-17671, Greece;
b
Institute of Geodynamics, National Observatory of Athens, Athens GR-11810, Greece;
c
Department of
Geography and Climatology, Faculty of Geology and Geoenvironment, National University of Athens,
Athens GR-15784, Greece
(Received 29 March 2012; Resubmitted 21 November 2012; Accepted 8 December 2012)
In this paper a geomorphological map, at a scale of 1:50,000, of the Cephalonia Island located
in the Ionian Sea (western Greece) is presented and discussed. The geology of the island is
represented in an individual smaller inset map. The map was produced from field surveys
based upon 1:50,000 scale topographic maps and 1:5000 topographic diagrams, differential
global positioning system surveys, aerial photos and visual inspection and interpretation of
Google Earth images, and analysis of a digital elevation model of the island derived from
1:50,000 scale topographic maps. Landforms were grouped on the basis of the main
morphogenetic processes and include fluvial landforms, erosional landforms, gravitational
landforms, karst landforms, and coastal features. The objective of this map is to provide
information about the landscape evolution of the island during the Quaternary. The study of
the landforms depicted on the geomorphological map showed that the recent evolution of
the landscape is dependent mostly on neotectonic processes and eustatism.
Keywords: geomorphological map; Cephalonia Island; Greece
1. Introduction
Geomorphological mapping is an important tool for reconstructing both long-term and short-term
landscape evolution. The present study aims at a better understanding of the geomorphic
evolution of Cephalonia Island during the Quaternary through geomorphological mapping at
1:50,000 scale.
Cephalonia Island occupies an area of 781 km
2
and is located in the Ionian Sea (Western
Greece) in a particularly tectonically active area (Figure 1). The evolution of the island is depen-
dent mainly on the behavior of the Hellenic arc, which lies offshore just west of Cephalonia.
Geodynamic processes in the region are related to the active subduction of the African lithosphere
beneath the Eurasian plate, which progressively becomes continental convergence in north-
western Greece (Figure 1). The transition occurs along the Cephalonia fault zone, a prominent
# 2013 Journal of Maps
∗
Corresponding author. Email: karymbalis@hua.gr
Journal of Maps, 2013
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dextral strike slip fault, located offshore, west of the island (Louvari, Kiratzi, & Papazachos,
1999; Scordilis et al., 1985).
The dominant long-term vertical movement of the island during the Quaternary is uplift.
Gradual uplift from the beginning of the Pleistocene has left its imprint on the landscape of
Cephalonia. The existence of a series of uplifted marine terraces which have been carved
mainly on Pliocene formations along the coasts of the southern part of Cephalonia in addition
to the presence of fragmented erosional – disolutional planation surfaces at various elevations
on the carbonate rocks of the Alpine bedrock, indicate the importance of neotectonics in the
geomorphic evolution of the island.
Figure 1. Topographic map of Cephalonia Island and location map depicting the geodynamic setting of the
broader Aegean area (geodynamic setting map is based on Gaki-Papanastasiou, Maroukian, Karymbalis, &
Papanastassiou, 2011).
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2. Methods and data used
The data presented in this work were acquired through an integrated geological and geomorpholo-
gical study. For the geological mapping, field observations were combined with previous published
geological maps of the island (British Petroleum Co. Ltd., 1971; IGME, 1985) while geomorphic
features were identified and mapped through aerial photo and Google Earth image visual inspection
and interpretation, digital elevation model (DEM) analysis and extensive fieldwork.
In order to produce the final maps a geographic information system (GIS) spatial data base
was designed, organized and implemented using ESRI’s ArcGIS9.3 software aiming at the cre-
ation of a number of thematic and synthetic layers and maps in a common projection system
(Hellenic Geodetic Reference System 1987 – HGRS’87) (Figure 2).
Input data were four sheets of 1:50,000 scale analogue topographic maps dating to 1976 of the
Hellenic Military Geographical Service cove ring the island, 30 topographic diagrams of 1:5000
scale covering the Paliki peninsula, the area between Ag. Kyriaki Bay and the Argostoli Gulf, and
the southern part of the main island, two sheets of 1:50,000 geological maps published in 1985 by
the Institute of Geology and Mineral Exploration of Greece, a geolog ical map published in 1971
by BP Co Ltd at 1:100,000 scale and orthorectified aerial photos from 1996 at 1:33,000 scale
obtained from the Greek Ministry of Agriculture. Analogue maps were scanned and georefer-
enced in the Hellenic Geodetic Reference System 1987. These data were the source for the cre-
ation of the primary thematic layers (with point-to-point on screen digitizing) which include
Figure 2. Flow diagram showing the main steps of the mapmaking method.
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coastline, contour lines (with 20-m contour interval – 4 m for some areas), isobaths, elevation
points, stream networks, geological formations, faults, upthrusts and fold axes. The geological
formations layer was used as intersection with flat surfaces.
GIS procedures produced secondary layers which included a raster DEM of the island, a hill-
shade map, a slope-aspect map, a range map and a map of morphological discontinuities of slopes.
The basic input data for the production of the DEM were contours with a good density (20-m
contour interval, as well as 10 m in some relatively flat regions) together with elevation points and
the drainage network from the 1:50,000 scale paper maps. The TOPOGRID algorithm in ArcGIS
9.3 was used to generate a 20-m resolution DEM of Cephalonia Island.
Slope-aspect maps represent the slopes of the terrain classified in regions, as well as the aspect
of the slope. The slopes on the island were classified in the following categories: 0 –5%, 6–15%,
16– 30%, 31–45%, 46–60%, slopes .60%. The angles of aspect were categorized by 458 and
were transformed in to Arc/Info format.
The island was divided in categories of 20-m elevation zones. These zones were contained in a
range polygon layer. The layer of morphological discontinuities of slopes was a compilation of the
thematic layers of aspect, slope and range. The morphological discontinuities are boundaries of
polygons with specific characteristics in the layer of the slopes and represent the differences in
slope of more than 20%. This layer was useful for mapping abrupt breaks of slope.
Aerial photos and Google Earth images were used for visual inspection and interpretation
along with DEM analysis as a first step to generate the tentative preliminary map as a base for
fieldwork. Some of the landforms (planation surfaces, poljes, dolines, intense downcutting,
marine cliffs, marine terraces, landslide scarps and bodies) were initially digitized directly in
Google Earth where they were saved as KML-files. These were then converted to shapefiles
using the Department of Natural Resources Garmin application (http://www.dnr.state.mn.us/
mis/gis/tools/arcview/ extensions/DNRGarmin/DNRGarmin.html) and organized in thematic
layers according to the type of each landform.
Field mapping survey (using Differential Global Positioning System or DGPS) was carried
out to check and evaluate the accuracy of the landforms initially derived from inspection and
interpretation of aerial photos and Google Earth images and DEM analysis. The field survey com-
bined classic field mapping with DGPS survey. Classic field mapping at the detailed scale (topo-
graphic maps at 1:5000 scale with 4-m contour lines) was performed for the Paliki Peninsula and
the south part of the main island for identification and mapping of marine terraces, uplifted bea-
chrocks and marine notches while for the rest of the study area field recognition of landforms was
achieved using the topographic maps at the scale of 1:50,000. A Topcon GMS-2 DGPS was used
in the field to check landforms’ boundaries accuracies (mainly polygon-type features like geologi-
cal formations, landslide bodies, marine terraces, planation surfaces, alluvial fans, karst land-
forms). The accuracy of the DGPS used is considered to be suitable for both 1:50,000 and
1:5000 scale field survey. DGPS was also used also to mark linear features such as coastal land-
forms (beaches, cliffs, notches) slope changes, and ridges as well as to determine and mark the
precise location of point landforms (mainly knickpoin ts, caves, uplifted beachrocks, etc).
Results from the above methods were summarized in a 1:50,000 scale geomorphological map.
A 20-m resolution gray-scale hillshade map of the island derived from the DEM was used as the
background of the final map.
2.1. Climate and hydrology
Western Greece is located on the preferential paths of the Mediterranean cyclonic systems
accompanied by frontal zones which are responsible for the development of torrential rains
especially during autumn and winter.
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The isohyet and isothermal maps (Figure 3) for the island show the distribution of mean
annual precipitation and average air temperature, respectively (Katsafados, Kalogirou, Papado-
poulos, & Korres, 2012). Mean annual precipitation varies from 820 mm at the southern part
of the island to more than 900 mm at its eastern part. The mean annual temperature range is
almost 0.78C with a northeastern to southwestern slight increase gradient.
In addition to the European Centre for Medium-Range Weather Forecasts gridded long-term
means, the climatology of the accumulated precipitation and the near surface temperature was
extracted from the conventional meteorological station which is located in the capital of the
island, Argostoli and belongs to the surface observation network of the Hellenic National Meteor-
ological Service. According to the 27-year records, the mean annual precipitation is 718 mm,
unevenly distributed throughout the year, with most (636 mm) falling during winter and the tran-
sient periods (Figure 4). The wettest months of the year are October, November, December and
January with mean precipitation of 99.9 mm. The mean annual air temperature at Argostoli is
18.18C, while the warmest month of the year, August, reveals an average temperature of
25.98C. Moreover the coldest months of the year are January and February with an average temp-
erature of 11.58C.
Figure 3. (a) Isohyet and (b) isothermal maps of Cephalonia Island based on the European Centre for
Medium-Range Weather Forecasts (ECMWF) gridded analyses. Mean annual temperatures refer to the
period from 1990 to 2007 while mean values for precipitation refer to the period from 1980 to 2001 (Katsa-
fados et al., 2012).
Figure 4. Diagrams of monthly averages for (a) precipitation and (b) mean air temperature over a year for
the period 1970–1997 at Argostoli meteorological station.
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Under the Ko¨ppen classification, Cephalonia climate belongs to the dry-summer subtropical
category usually referred to as typical Mediterranean and encoded as Csa. The relatively high pre-
cipitation and the high mean annual temperature in addition to the dominance of carbonate rocks
(limestones and dolomites) are favorable conditions for the extensive development of karst
landforms.
All surface and ground water in the study area is the result of precipitation. Changes in cli-
matic conditions such as precipitat ion and temperature can cause large and rapid changes in
streamflow and more gradual changes in ground water flow. The streams of the island are of sea-
sonal flow and there are no discharge gauges.
The island has not received m uch attention on water quality. However a three-year monitoring
study assessed the chemical and microbiological quality of the harvested rainwater of the northern
part of the island (Sazakli, Alexopoulos, & Leotsinidis, 2007). Chemical analysis of rainwater and
mixed or ground water showed that the PH values range from 7.63 to 8.80 with a mean value of
8.35, indicating that in the studied area the rain is not acid. Rainwater has low-medium values for
conductivity (median conductivity 103 mScm
21
) and low-medium level of ions of marine origin
(median Na
+
: 6 ppm, Cl
2
: 7 ppm). Rainwater contains the elements Ca and Mg in relatively ade-
quate concentrations. The highest value of hardness measured in rainwater was 74 mg l
21
CaCO
3
and the median value was 40 mg l
21
CaCO
3
. Fluoride is not detected in rainwater while Metals,
either essential or toxic, are present in traces (Sazakli, Alexopoulos, & Leotsinidis, 2007). In
general, conductivity and most of the ions show lower values in rainwater than in mixed or
ground water. Manganese and Cadmium are present in lower levels in rainwater than in other
water, while mean PH was higher in rainwater (Sazakli, Alexopoulos, & Leotsinidis, 2007).
There is a seasonal variation for some main ions and consequently for conductivity, with
higher values being detected in winter.
3. Geological setting
The bedrock of the island consists of two main bedrock units: (1) the east dipping, NW to NNW
striking, thrust sheet fragments of a carbonate platform belonging mainly to the Pre-Apulian (or
Paxos) geotectonic unit (Underhill, 1985), and (2) the Ionian unit occupying a relatively small
part of the eastern island (BP Co Ltd, 1971; IGME, 1985).
The individual smaller inset map shows that the Pre-Apulian (Paxos) geotectonic unit consists
of Cretaceous limestones and dolomites overlain by Paleocene– Eocene–Oligocene (?) thick-
bedded limestones. On top of them lie conglomeratic and brecciated limestones of Upper
Oligocene to Upper Miocene age.
The Ionian geotectonic unit formations outcropping in the island are Pantocrator limestones of
Upper Trias–Middle Lias age overlain by the Upper Lias-Middle Dogger age Ammonitico Rosso
formation, which consists of thin bedded platy limestones with marly intercalations. Middle-
Upper Dogger is represented by alternations of shales and limestones overlain by Vigla
limestones with chert layers of Upper Jurassic–Lower Cretaceous age. On top of them Upper
Jurassic–Lower Cretaceous breccias and limestones occur while Paleocene and Eocene is
represented by limestones.
This basement is overlain by extensive outcrops of Neogene and Quaternary deposits in the
southern and eastern part of the Paliki peninsula and the south part of the main island. In the
Lower Pliocene there is a short stratigraphic hiatus and a transgressive well-bedded conglomeratic
facies. These conglomerates are overlain by a limestone bed passing upwards into sand, sandstone
and sandy limestone with layers of blue marls. Upwards, the blue marls predominate and enclose
a rich mollusc fauna while in the uppermost part a series of fine-grained sandstones and sandy
marls reappear. Pleistocene formations are composed mainly of conglomerates and sandstones
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and occur at the north part of Paliki peninsula and along the southern foot of Aenos Mt. At
locations along the eastern coast of the Paliki peninsula, sandstone formations were observed
capping hills whose elevations reach 160 m a.s.l. while beachrock formations at elevations
between 21.6 and 6.5 m of Tyrrhenian age exist in the southern coasts of the main island and
the Paliki peninsula (Braune, 1973; Sorel, 1976 ). The Holocene deposits consist of alluvial
fans, scree, and high-energy fluvial deposits mainly deposited along the stream channels as
well as solution depression fillings consisting of terra rossa and fluvial sand and gravels.
The dominance of carbonate rocks in combination, with favorable climate conditions for dis-
solution, have enhanced the formation of karst landforms especially in the north and central part
of the island. The southern part of Cephalonia where Pliocene and Pleistocene formations occur is
dominated by the presence of uplifted marine terraces, which correspond to past sea-level high-
stands. These uplifted marine terraces at gradually higher elevations are morphological markers of
sea-level fluctuations and continuous tectonic uplift during the Quaternary. Furthermore, gradual
tectonic uplift of the island led to the formation of erosional planation surfaces on the Alpine
carbonate bedrock.
The general trend of the faults is mainly NW– SE with some secondary ones having NE–SW
direction. The area is characterized by intense seismicity with strong frequent earthquakes. Since
the fifteenth century, 21 earthquakes with magnitudes greater than 6.5 have severely affected the
island while nine of them have occurred during the last century (Papazachos & Papazachou,
1997). During the last millennia two vertical displacements have been verified, which affected
most of the island, associated with co-seismic uplift. The first occurred between 350 and 710
AD and the second during the 1953 earthquake, which mainly uplifted the southeastern part of
the island by 50 and 70 cm, respectively. (Pirazzoli et al., 1994, Stiros, Pirazzoli, Laborel, &
Laborel-Deguen, 1994). Recent studies performed by different teams, based on GPS,DGPS
measurements and Permanent Scatterer Interferometric analysis covering the period 1992 to
2010, have revealed horizontal clockwise rotation of Cephalonia with velocities ranging from
3to8mm/yr, the largest values occurring at the western and southern parts of the island
(Cocard et al., 1999; Hollenstein, Geiger, Kahle, & Veis, 2006; Lagios et al., 2007, 2012). For
the vertical deformation Lagios et al. (2012) distinguished two periods: the period 1992 to
2003 shows linear slight subsidence (around 1 mm/yr). The second period, 2003 to 2010,
shows uplift (2– 4 mm/yr) that occurred mainly along the southern and south-eastern parts of
the island, while larger magnitudes (.4mm/yr) took place at the western part. These results
present the complex tectonics of the island, indicating that it is composed of different tectonic
blocks that do not behave uniformly over time.
4. Geomorphic features
4.1 Drainage networks
The main mountain mass of Cephalonia Island is Aenos (1630 m a.s.l.) occupying the central part
of the island, oriented in a NW–SE direction. The principal water divide has the same direction
with a well developed drainage pattern on the eastern part of the main island where the two largest
fifth-order (according to Strahler’s (1957) classification system) networks exist. The main channel
flow directions of these networks are to the NE (Sami Bay) and the SW (Poros), with the devel-
opment of the main streams channels controlled by lithological contacts, faults and upthrusts. The
coastal zone of the southern part of the main island consists of relatively steep slopes with rela-
tively short streams of first and second order. The area bounding the eastern side of Argostoli
Gulf, is characterized by very steep limestone cliffs (with slopes between 39 and 78%) due to
the neotectonic origin of the Gulf (Gaki-Papanastasiou, Maroukian, Karymbalis, & Papanastas-
siou, 2011), with a small parallel not well-developed drainage network.
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The Erissos Peninsula, the central part of which is an extensive, partially karstified, planation
surface, is drained by short streams discharging directly into the sea (Main map). The eastern ones
are more heavily incised probably due to higher tectonic uplift rates since the east almost straight
cliffed shoreline of the peninsula is affected by a NNW –SSE trending coastal fault.
The northeastern part of the Paliki peninsula is drained by three major drainage networks with
the upper reaches flowing in a NNW – SSE direction and then turning to the east discharging into
Argostoli Gulf. The uppermost parts of these drainage networks are the oldest as they have
evolved on limestones of Eocene–Oligocene and Miocene age while their lowermost parts
passing through the Pliocene formations are much younger (Gaki-Papanastassiou, Karymbalis,
Maroukian, & Tsanakas, 2010). These drainage networks were tributaries of a much larger drai-
nage pattern which was active during the last glacial period up until early Holocene. The main
channel of this drainage network had an almost N– S direction flowing along the eastern side
of the present Argostoli Gulf which was a valley during the early Holocene (Gaki-Papanastasiou,
Maroukian, Karymbalis, & Papanastassiou, 2011). The submarine continuation of drainage net-
works in the area around the Argostoli Gulf is depicted on the Main map. The bathymetry of the
gulf reveals that it is a shallow submarine valley with a maximum depth of about 25 m east of cape
Ag. Georgios. Its western submarine slopes are less steep than the eastern ones probably due to
structural reasons since the strata on the western Paliki peninsula are dipping toward the gulf as
well as due to the deposition of sediments supplied by the drainage networks of the Paliki penin-
sula. At the southern part of the Paliki peninsula there are two drainage networks. Their upper
parts have developed on limestone formations having a low drainage density while their more
extensive lower parts drain Pliocene formations.
4.2 Karst landforms
The Main map shows that the island is intensely karstified with the presence of dolines, poljes,
sinkholes and caves. Karst landforms occur in association with the highly soluble carbonate
rocks of Cretaceous age. The most remarkable surface karst landforms are the Valsamata and
Trogianata poljes (Figure 5a). Smaller karst depressions are located at the western part of the
island just north of the Argostoli Gulf.
Noteworthy in the central part of the Erissos Peninsula is the existence of a fragmented exten-
sive karst planation surface ranging in elevation from 200 m in the north to more than 800 m in the
south (Figure 5b). Karst fill sediments tend to be a mixture of terra rossa and high-energy fluvial
deposits. Caves are widely distributed over the island particularly in the broader area of Sami
and southeast of Argostoli.
Figure 5. (a) The polje of Valsamata; (b) Karst depression on the extensive planation surface of Erissos
Peninsula.
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Cephalonia Island is the site of one of the most astonishing hydrological phenomena in the
world. Seawater current flows continuously into the karstic substratum of the island through sink-
holes which have formed in fractures in the carbonate rocks on the southwest coast near the town
of Argostoli (Drogue, 1989). Current flow can reach as much as 0.3 m
3
s
21
and is sufficiently
powerful to drive millwheels. Maurin & Zotl (1967) used a tracer to show that the seawater
reappears on the eastern coast of the island as brakish springs (near the town of Sami). The under-
ground route is 15-km long.
4.3. Planation surfaces
In the study area several planation surfaces located at different elevations ranging from 100 m to
more than 1300 m around Aenos Mt. were mapped. All the fairly flat surfaces developed on th e
Alpine bedrock (limestones of Jurassic and Cretaceous age) have been mapped as planation sur-
faces. These surfaces were formed by the combined action of erosion and disolution and their
development probably reflects the gradual tectonic uplift of the island. During geomorphological
mapping, denudation surfaces were grouped according to their elevation into nine classes. Dissol-
ution seems to be most important for the development of the extensive karstified planation sur-
faces of the Erissos peninsu la. It is possible that planation surfaces represent remnants of older,
fewer and more extensive erosional surfaces that were subsequently tectonically segmented
into smaller pieces located at different elevations today (Gaki-Papanastasiou, Maroukian,
Karymbalis, & Papanastassiou, 2011). On the north and east slopes of Aenos Mt. fragmented
pediment surfaces were identified and mapped ranging in elevation from 340 to 720 m a.s.l.
(Figure 6). These surfaces show features typical for a pediment that are up to 1.5-km wide and
inclined toward the neighboring valleys at 15%. Locally the surfaces are separated from the
stream valleys by distinct erosional escarpments.
Figure 6. Pediment surface developed on carbonate rocks at an elevation of 500 m, on the northeast slopes
of Aenos Mt., west of Poros.
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4.4. Gravitational landforms
In the course of the fieldwork, a landslide was recognized and mapped at Zola village probably
triggered by the re-activation of a normal NE–SW trending fault located west of the settlement by
a strong earthquake. The nearby identical slope of the mountain sides and the dip of the strata
played a major role in causing this landslide (Figure 7). This mass wasting event occurred
some hundreds of years or a few thousand years ago (Gaki-Papanastasiou, Maroukian, Karymba-
lis, & Papanastassiou, 2011). Along the slopes of the eastern coast of Agia Kyriaki Bay, mudflows
and debris flows are observed. Locally the activation of these movements is enhanced by the
susceptibility to failure of the Miocene formations. Along the steep coasts of the island and
particularly on the eastern and western sides, rock falls are very common.
4.5. Coastal geomorphology
About two thirds of the total coastline length of the island is characterized by steep slopes
(ranging from 21% to 96%) with the occurrence of more than 15 pocket beaches (Figure 6a; h).
The main map shows that the western coast of the Paliki peninsula is steep (with slopes between
54% and 96%) comprising limestone cliffs that reach the maximum height of about 240 m a.s.l.
(Figure 6a). This part is subject to coastal erosion. On the other hand, the eastern coast of Paliki
is characterized by much lower slopes and sandy beaches. Three small coastal fans have formed
at the mouths of the major drainage systems along the western shores of the Argostoli Gulf. The
main reasons for these differences in the coastal geomorphology are the lithology (the western
coasts consist of hard to erode limestone formations while the eastern part is composed of highly
erodible Pliocene formations) as well as the tectonic regime of the peninsula which was character-
ized by gradual uplift raising the older limestone formations and creating a NNE–SSW slope of the
carbonate platform (Gaki-Papanastassiou, Karymbalis, Maroukian, & Tsanakas, 2010)
In most of the southern coast steep cliffs occur (with slopes ranging from 32% to 64%) except
in some parts where Pliocene conglomerates, sandstones and marls exist. There, sandy beaches
Figure 7. Landslide along the steep slopes of Agrilia Mt.
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are located around the Capes Ag. Nikolaos, Ag. Pelagia, Liakas and Lourdata Bay. High cliffs are
observed where Aenos Mt approaches the coast, between Capes Katsonas and Koroni.
In the Paliki Peninsula, as well as along the southern coast of the main island, several uplifted
geomorphological features were mapped, including marine terraces, marine notches, beachrocks
and aeolianites. Remnants of Quaternary marine terraces have been identified at several locations
on the island. The uplifted Quaternary marine terraces are excellent morphological markers and
have been used worldwide to recognize past sea-level changes. Their correlation with the main
interglacial highstands can be done only in areas where a continuous uplift at a regional scale
exists combined by dating their exposure. Along the coasts of southern Cephalonia Island the
existing uplifted marine terraces are imprinted into pre-existing Mio-Pliocene marine formations
and only a few of them have a thin sandstone caprock. However it was difficult to find datable
material and we were unable to correlate the terraces in space and time. Nevertheless, the occur-
rence of the terraces of Paliki peninsula and of the southern part of the main island, at different
elevations, supports the suggestion that the island is compos ed by different tectonic blocks
moving disparately.
The detailed field geomorphological mapping revealed a sequence of eight marine terraces in
the Paliki peninsula (Figure 8a and b). The lower two terraces are the most continuous and well
preserved and are located at elevations between 2– 16 and 18 –32 m a.s.l. respectively. Remnants
of higher marine terraces were distinguished at elevations between 34 –60, 60 –74, 76 –112,
136– 160, 180 –300 and 300– 440 m a.s.l., respectively. The inner edges of these higher platforms
Figure 8. (a) Marine terraces at 90 m a.s.l. Steep faulted limestone cliffs are also seen in the background.
Cape Schiza, western coast of Paliki; (b) The lowest marine terrace (2 –16 m a.s.l.) photographed from the
second terrace west of Cape Ag. Georgios, southern shore of Paliki; (c) Uplifted marine terraces and notch at
Cape Kapri, SE area of the island; (d) The pocket beach of Myrtos.
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were difficult to distinguish mainly due to the erodible lithology of the Pliocene formations. The
three higher marine terraces, which have developed on Eocene – Oligocene limestone, seem to
represent former shorelines which should have been carved during the Pliocene.
In the southern part of the main island there exist eight uplifted marine terraces extending
along a narrow coastal zone in the southeast and southwest corners (Figure 8c). They are
mainly formed on Pliocene formations and range at elevations 2–4, 4– 20, 20–40, 40 – 60,
60– 90, 92– 140 and 142– 170 m a.s.l.
On the main island three Late Holocene uplifted marine notches were identified reaching up to
3 m a.s.l. At the southern and southeastern coast of Paliki peninsula uplifted beachrocks at 5 m
a.s.l. were observed together with aeolianites reaching a height of 5 to 6 m a.s.l. and a marine
notch at 1–2 m a.s.l. (Figure 8c).
Based on the raised coastal features of the study area it becomes evident that the prevailing
tectonic movement is positive (emergence) during the Pleistocene and Holocene periods. The
slightly higher elevations of the marine terraces in the southern part of the main island, in com-
parison with those of Paliki peninsula, are evidence of relatively higher rates of uplift during th e
Quaternary.
5. Conclusion
The geomorphological map o f Cephalonia at the scale of 1:50,000 presented in this work
portray the distribution of landforms and earth surface processes over the island and lead to con-
clusions about the recent evolution of the landscape. Geomorphological mapping has shown
that geomorphic features reflect the importance of neotectonic processes in the recent evolution
of Cephalonia. A large part of the southern island was underwater during the Pliocene. From the
beginning of the Pleistocene gradual uplift of the area began, raising the older limestone for-
mations. In the Paliki peninsu la carbonate marine terraces were formed dipping NNE–SSW,
with the younger marine terraces carved on the Pliocene formations. The terraces extend in a
north–south direction, while on the main island they are from west to east. Given the different
elevations of the marine t erraces as well as the other uplifted coastal geomorphological features
of the island, the two parts (Paliki Peninsula and the s outhern main island) had different uplift
regimes being located on different tectonic blocks. Marine terraces at the southern part of the
main island were mapped up to about 20 m higher than those of the same group which are
located at Paliki peninsula. This is evidence of slightly higher uplift rates during the Quaternary
for the southern part of the main Cephalonia Island. Elevation differences between the erosional
planation surfaces reveal the importance of neo-tectonism on the behavior of these blocks. The
highest elevation where Pliocene formations exist in the Paliki peninsula is 160 m a.s.l. while in
the southern part of the main island they reach 170 m a.s.l. The minimum long-term tectonic
uplift rate for t he southern part of Cephalonia during the Quaternary, is estimated to be about
0.2 mm/yr.
The existence of uplifted marine notches as well as uplifted beachrocks and aeolianites along
the coastline of the southern island indicate the recent Holocene uplift of this part of the island.
Software
ESRI ArcGIS 9.3 was used to digitize the data collected during field survey and aerial photo
interpretation. The DEM was derived from topographic maps at a scale of 1:50,000 obtained
from the Hellenic Military Geographical Service. The final layout of the geomorphological and
geologic map was assembled using Corel Draw12.
12 E. Karymbalis et al.
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Acknowledgements
We would like to thank Dr Paolo Paron and Dr Mike Smith, Editors of the Special Issue and two
anonymous reviewers for their helpful suggestions, comments and corrections that significantly improved
the paper.
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