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Zeitschrift für Geomorphologie, Vol. 60/1 (2016), 1–14
Article
Published online January 2016
Abstract: Despite the large variability of landforms in Montenegro, no attempts have yet been made to regionalize
its geomorphology. However, Digital Elevation Models are globally availability and in recent decades we have seen
a strong increase in computation possibilities to map and quantify relief. Here, we used the Geomorphon method to
of a regional geomorphological map of Montenegro at scale 1:800,000. In total, seven geomorphological regions
were recognized: Coastal Montenegro, High Karst, Inland Depression, Durmitor Flysch, Northwestern Highlands,
Prokletije and the Northern Cristalline Hills. Karst landforms largely dominate the geomorphology of the country,
with the occurrence of numerous dolines, uvala’s, large poljes (Gradaj, Grahovo and Njeguši) and karst plateaus
the Geomorphon method allowed making a rapid assessment of the country’s main geomorphological characteris-
Keywords: Digital Elevation Model, Geomorphon, Karst, Map, Njeguši polje
In terms of landforms, Montenegro (Crna Gora) shows
a great variability, ranging from sand and rock coasts
(some corresponding to a ria coast), karst plateaus, large
(intra-montane) poljes, high mountains holding a (peri)
glacial imprint, canyons, and more; all of it comprised in
only 13 812 km² and within an elevation range of 2535 m.
occurring (e.g., karst-glacial interactions described by
given to synthesising the geomorphology of Montene-
publications in that regard. Most of these publications are
-
morphological processes. Furthermore, many regions of
Montenegro are not yet covered in past research.
Geomorphological mapping has tremendously
based approaches and the interpretation of stereoscopic
aerial photographs (Verstappen 2011), contemporary
approaches focus increasingly on the use of Digital Ele-
-
gen 2013). DEMs indeed capture both the morphology
and the morphometry of landscapes and over the past
help detecting and classifying landforms. Interpreting
-
The regional geomorphology of Montenegro
5
Fig. 1. Geomorphon classificatio of Montenegro. (a-g) indicate some examples of geomorphologies which can be easily
detected and which are also explained in the result sections: (a) Dalmatian zone consisting of an anticlinal structure, (b) Ban-
jani karst plateau which shows large proportions of flat areas, (c) polje of Nikši which is very distinct by a flat zone, (d) Zeta
valley incising the inland depression as a valley, (e) Mora river which forms a canyon in the High Karst Zone and a dense
dendritic river valley network in the Durmitor flysch Zone. (f) wide U-shaped glacial valleys in the Durmitor mountains and
(g) very wide U-shaped glacial valley in Prokletije.
6
A. Frankl et al.
Fig. 2. Geomorphological regions of Montenegro based on a classificationusing the Geomorphon method, literature and field
observations.
imprint is present, while more pronounced forms (includ-
ing glacial pavements and large moraines) are present
in the Orjen mountains (Hughes et al. 2010). Typical
for karst hydrography, springs and rivers are very rare,
despite the high precipitation of 2000 mm y
–1
(Kilibarda
2001). The Inland Depression (next section) cuts quite
brusquely through the region (Nicod 2003) and to the
N of this depression the elevation rises up to more than
2000 m a.s.l., making the transition with the Durmitor
Flysch zone.
8
A. Frankl et al.
outcrops identified as ‘keratophyre and quartz-kera-
tophyre’ on the geological map (Mirkovi et al. 1985).
These rock types are defined by Schermerhorn (1973)
as ‘leucocratic (greater than 90% felsic minerals) sodic
(more sodium than potassium) albite-phyric volcanic
rocks’. The S part, close to the village Vusanje, consists
of mesozoic limestones and dolomites. The E part, to the
SE of Plav, is more complex with Paleozoic (Devonian
and Carboniferous) phyllites and schists and Permian-
Triassic conglomerates. The geomorphological region of
Prokletije comprises the Prokletije mountains (which run
into Albania) but is nevertheless extended to the N until
Andrijevica and the west until the Komovi mountains.
Like the NW Highlands, Prokletije offers evidence of
past glaciations (Fig. 1g). Across the border, in Albania,
some still active glaciers were recently discovered, mak-
ing it one of the southernmost glaciers of the European
continent. In the Montenegrin part, numerous cirques,
glacial valleys and other periglacial evidences are found
(Milivojevi et al. 2008). Plav Lake provides a typical
example of a lake formed behind a terminal moraine;
located in the headwaters of the Lim river.
3.7 The Northern Crystalline Hills
This region includes Biogradska Gora National Park, the
Bjelasica mountains and the N zone forming the border
with Serbia around Pljevlja and Bijelo Polje (note that
is polje is located in a plain but has no karstic origin)
(Fig. 2). Flysch and sandstone sediments are dominant,
although carbonate rocks are still abundantly present.
The central part of the region, N and NE of Bjelasica
mountains, is dominated by Paleozoic (Permian, Devo-
nian and Carboniferous) sandstone and phyllites. Bje-
lasica itself rises above the surrounding Paleozoic
environment representing Triassic limestones and again
dark keratophyres. The NW part of the region, around
the town of Pljevlja, is again dominated by Jurassic and
Triassic limestones (Mirkovi al. 1985).
Despite the large variation in lithology, the general
abundance of softer material is reflectedin the landscape,
where smooth hills and valleys are formed due to higher
vulnerability to lateral erosion. Towards the NE and the
SW, the Ljubisnja and Hajla mountain chains, respec-
tively, reach elevation of more than 2200 m a.s.l. and
there, glacial features are characteristic. The Lim River
is the largest river draining this zone and large fluvio
glacial terraces can be found on its valley floo .
4 Discussion
4.1 Considerations for geomorphological
mapping
The resolution of the DEM is key in the ability to define
and map landforms from it. In a grid-based DEM, land-
forms should have at least twice the DEM-resolution
in order to be defined (Warren et al. 2004), which in
Fig. 3. Valley in the Durmitor massif showing glacial and periglacial features interacting with
karst landforms.
The regional geomorphology of Montenegro
9
this study sets the minimal landform size at 60 m. The
ASTER-DEM is thus mainly useful to define the main
characteristics of the relief. The regionalization of the
geomorphology occurred on the basis of both more clas-
sical methods (literature, maps, field observations, etc.)
and the Geomorphon output, allowing the rapid identi-
fication and delineation of regions that are morphologi-
cally uniform. A clustering based on the Geomorphon
method alone was, however, not performed. Using the
identified regions did allow us to compute the relative
proportions of the different morphologies that are dis-
tinguished by the Geomorphon method (Fig. 4). This
generally supports the regionalization of the geomor-
phology, with clearly larger proportions of flat surfaces
in the Inland Depression and Coastal Montenegro, and to
a lesser extent in the High Karst and Northwestern High-
lands (related to the Banjani and Jezerska Površ karst
plateaus respectively). For the High Karst, the dolines
are comprised in the categories pit, valley, footslope and
hollow; consisting of approximately 30% of the area. The
mountainous character of the country is marked by very
high proportions of the slope class.
In order to evaluate whether the Geomorphon method
(applied on the ASTERM-DEM) could facilitate or fas-
ten a field-based geomorphological mapping at scale of
1:25,000, the computational outputs were compared to
the map produced by Lenaerts (2014) over the Njeguši
polje (Fig. 5 and 6). The latter has an area of approxi-
mately 14 km² and is located on the border between
Coastal Montenegro area and the High Karst zone. As
can be viewed on the Fig. 5A, the S part of the study
area comprises of a glacial cirque with moraines at ca.
1000–1100 m a.s.l. Given the limestone lithology, karst
phenomena dominate the geomorphology, with doline(s)
(fields) making up approximately one fourth of the study
area. The central part is the polje floor(also the crop pro-
duction area), which is flanked by several springs on the
contact between the fine grained polje deposits and the
limestone flanks.On Fig. 5B, the main morphological fea-
tures identifiedduring the fieldmapping were compared to
the Geomorphon classificationof the area. In general, the
morphological classificationby the Geomorphon method
matches well the field-based interpretation of peaks and
crestlines. Slopes are also relatively well defined, and
thalwegs are classified in the slope ‘hollow’ or ‘valley’
Geomorphon classes, the latter when the topography is
more pronounced. The polje floor is largely defined as a
‘valley’ and only the polje floor is partly defined as ‘pit’.
Especially the representation of the polje floor by valley
is problematic as this does not fitthe general morphologi-
cal perception of a polje (which would be a combination
of ‘footslope’, ‘flat and ‘pit’). As expected, small scale
surface morphologies, such as individual dolines, doline
fields, scree slopes or moraines are less easily detected
from the Geomorphon output and their complex surface
morphologies is mostly reflectedin a mixture of different
Geomorphon morphologies (Fig. 5, Fig. 6).
4.2 Landform genesis
4.2.1 Ria coast
The term ‘ria’ is used to describe a former river valley sys-
tem developed in a high relief area that was drowned by
sea level rise. The resemblance of the morphology above
current sea level to a fjord could cause some confusion,
but a ria coastal system is not related to glacial processes
(Castaing & Guilcher 1995). In Montenegro, the Kotor
Fig. 4. Frequency distribution of the different morphologic units (as define in the Geomor-
phon method) for the geomorphological regions of Montenegro. CM: Coastal Montenegro,
HK: High Karst, ID: Inland Depression, DF: Durmitor Flysch, NW: North-western Highlands,
PO: Prokletije and NC: Northern Crystalline Hills.
10
A. Frankl et al.
Bay provides a typical example of this phenomenon
(Fig. 7A). There, the valley systems were formed mainly
during the Messinian Salinity Crisis (5.97 to 5.33 Ma;
Krijgsman et al. 1999), when the Mediterranean Sea was
nearly completely dry because of the uplift of Gibraltar
Street (Roveri et al. 2014). As a result, sea level – thus
erosion basis – was lowered with more than 1000 m,
allowing regressive erosion of the landscape. As fluvial
erosion continued, this resulted is a very deep incised
morphology under the current sea level by a river flo -
ing in NE-SW direction, orthogonal to the orientation of
the anticlinal structures, with its tributaries, parallel to
the anticlines. In the hard carbonates, narrow and steep
valleys were incised while in the soft flysch layers the
river and tributaries formed wide valleys, causing the
NW-SE orientation of the bays (Magas 2002). A more
subtle example of a ria system is probably the W bank
of Skadar Lake, where the outflow of Rijeka Crnojevi
shows a strong resemblance to a drowned fluvial system
(Fig. 7B). This would indicate that Skadar Lake at some
point would have been part of the Adriatic Sea. Due to
the low elevation difference (ca. 5 m) between Skadar
Lake and the Adriatic Sea, with the Bojana sometimes
noted to flow upstream, it is however unlikely that the
Bojana alone has created such an alluvial plain. It is prob-
able that this landform is in fact part of the alluvial plain
of the Great Drin, the longest river in Albania, flowing
into the eastern part of Skadar Lake. A possible expla-
nation for the formation of Skadar Lake was provided
by Ager (1980), stating that an inlet of the Adriatic Sea
would have been closed by dune formation. The fiel -
work nonetheless suggested that the dune formation S of
Ulcinj is rather limited, with eolian sedimentation up to
maximum 2 m. Therefore, it seems highly unlikely that
the formation of dunes closed the inlet of the Adriatic Sea
to Skadar Lake.
Fig. 5. Use of the 30 m resolution ASTER-DEM based Geomorphon classification for detailed geomorphological mapping in
the Njeguši polje, A: detailed geomorphological map of based on fieldwork (Lenaerts 2014), B: Geomorphon classification
based on the 30 m resolution ASTERM DEM (morphological features from A given as an overprint). Note that the general
morphological signature of the Njeguši polje is well comprised in the Geomorphon classificationbut that small-scale landforms
are generally not well represented.
The regional geomorphology of Montenegro
11
Fig. 6. The Njeguši polje.
Fig. 7. Ria forms in Montenegro, A: Kotor bay and, B: Rijeka Crnojevi
12
A. Frankl et al.
4.2.2 Canyons
As distinct landforms, numerous steep and narrow can-
yons deeply incise the limestone formations in Monte-
negro. This incision is due to epirogenic uplift (Nicod
2003) and a combination of alternating glacial and inter-
glacials cycles inducing sea level change during the
Quaternary. Nevertheless, it is unlikely that such deep
incisions (500–1000 m) were caused only in Quaternary
times. Most probably, these incisions are mainly caused
by a more extreme sea level lowering event such as the
Messinian Salinity Crisis. Canyons often form in karst
lithologies because of the strong resistance of carbonate
rocks to erosion, resulting in a vertical incision and thus
narrow valleys. Three different classifications of water
streams are identified to have formed the deep incisions:
glacial meltwater streams, streams influencedby climatic
oscillations and torrential streams (Djurovi & Petrovi
2007). The main canyons cutting through the Montene-
grin terrain are indicated on the geomorphological map:
Mora (Fig. 8), Cijevna, Mala Rijeka, Tara, Sušica and
Piva. An important note concerning the aforementioned
theory is that the rivers flowing through the three latter
canyons are part of the catchment of the Black Sea catch-
ment, whereas the Messinian Salinity Crisis is corre-
lated with the Mediterranean Sea. Scientists have found
evidence of shallow-water sediments (Pebbly Breccia
unit), leading to the assumption that the Black Sea was
equally influenced by the Messinian Salinity Crisis (Hsü
& Giovanoli 1979). This hypothesis was supported by
the detection of a widespread Messinian erosional sur-
face, several hundreds of meters lower than today (Gillet
et al. 2007). However, the presence of certain fossils in
the Mediterranean pointed to the fact that that there was
still an influx from the Paratethys, the Black-Caspian sea
of that time. Furthermore, a new stratigraphic correlation
shows that the shallow-water sediments are dated older
than 6.04 Ma, thus from before the Messinian Salinity
Crisis (Grothe et al. 2014). These hypotheses are some-
what contradicting, but in any case the presence of the
Pebbly Breccia unit points out the fact that the erosion
basis used to be very low at some point, probably before
the Messinian Salinity Crisis. This means that the can-
yons part of the present-day Black Sea catchment have
been the subject of similar processes, although not neces-
sarily at the same time.
5 Conclusions
Applying the Geomorphon method on the 30 m resolu-
tion ASTER-DEM allowed us to produce a geomorpho-
logical map of Montenegro at scale 1:800,000. Jointly
with more classic approaches, the Geomorphon approach
allowed to characterize seven main geomorphological
regions in the country: Coastal Montenegro, the High
Karst, the Inland Depression, the Northwestern High-
lands, Durmitor Flysch, Prokletije and the Northern
Crystalline Hills. This interpretation was supported by a
literature review and own field observations during sev-
eral field campaigns
While presenting the first regional geomorphological
map of Montenegro, this research also stresses that a very
large variability in landforms exists in the country, that
stretches over only 13 812 km² and is comprised within
an elevation range of 2535 m. Karst landfroms dominate
the landscape with the occurrence of numerous dolines,
uvalas, large poljes (Gradaj, Grahovo and Njeguši) and
a karst plateaus (Banjani, Jezerska Površ). Limestone
areas are often dissected by impressive canyons (Mora
Cijevna, Mala Rijeka, Tara, Sušica and Piva), of which
the formation is ought to be parallel with that of the ria
coast. The latter gave existence to large submerged river
valleys that were scoured during the Messinian Salinity
Crisis. Besides karst morphologies, glacial features are
important in the highest mountains, especially in the
Durmitor and Prokletije massifs.
Testing the performance of the Geomorphon method
at finerscales was done for the Njeguši polje (for which a
field-based map at scale of 1:25,000 was produced), and
showed that the method has good potential in supporting
detailed geomorphological studies.
Fig. 8. Mora
