Download geomorphology of the upper part of kocaçay river basin

International Symposium on Geography
Environment and Culture in the Mediterranean Region
GEOMORPHOLOGY OF THE UPPER PART OF KOCAÇAY
RIVER BASIN,
(İVRİNDİ-BALIKESİR, NW ANATOLIA)
Kamile GÜLÜM1
Abstract
Study area: the upper watershed of Kocaçay river-basin is located on the south of the
Marmara Region. It covers an area of 751 km². Policyclic topografic forms are dominant
since different tectonic and climatic process have affected the study area. The land forms of
the study area are closely related to the lithological properties. Dominant topographic shapes
are plateaus as they are dissected by running water.
Although the dominating topographical features today show a mature type of
topography, valleys are generally younger. Drainage systems have mostly been formed
during the Pliocene Age . It has been developed in the Quaternary. In fact, the valley system
is of the Plio-Quaternary period. The topographical discordance found in the study area is
probably the result of Post-Alpine tectonical uplift that occurred at the end of the Pliocene
Age and the beginning of the Quaternary.
There are three erosional surfaces at an elevation of 550-750 meters, 300-520
meters, and 210-300 meters. These surfaces indicate different erosional and depositional
process to have occured in the study area. In other words, tectonic movements are
responsible for the formation of erosional and depositional surface. Erosional activities
continue in the river valley since the base level is lowered or backward. As a result, the
erosion process continues. Valleys are still in the character of young valleys. In fact, when
the topography in the upper track of Kocaçay river basin is considered as a whole, one can
say that the development is still in the young stage.
Key words: Gemorphology, Kocaçay, superimpose valley
Introduction
The Upper part of the Kocaçay Rivershed, which is handled as the research area, is
located in the Southern Marmara Region in the northwest of Turkey.
The research area neighbours with the Manyas Plain in the north, Balıkesir Plain in the east,
Savaştepe Plateau in the southeast, Madra Mount in the southwest, Edremit Plain in the
west, and Şap Mount in the northwest. The area, which is blocked by the mountains in the
northwest and southwest, extends towards the southeast and southwest.
The Madra River (Kocaçay), which is formed through the plains on the base of the
valley and plateaus with the altitude of 300-850 m, is the dominant element of the research
area. The highest point in this area is Maya Hill(1344 m) on Madra Mountain and the lowest
point of this area is İvrindi Plain (200 m).
In the fields where the South Marmara climate is dominant, the vegetation is made of
the poor forests constituted of the bushes and cluster pines and oak trees in the low
altitudes. In contrast, in the high altitudes where the humidity increases with the altitude on
Madra Mountain and Şapdağ, there are robust forests consisting of black pine trees and
chestnut formations. The vegetation has been destroyed over the years in a large extent.
The forests exist in the south-southeast and north-northwest areas.
There are various kinds of soil in the research area. In general, the dominant soil is
zonal soil. But there are also azonal soils made on the alluvial and colluvial deposits. The
1
University of Adıyaman
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Environment and Culture in the Mediterranean Region
kinds of soil that dominantly exist in the area are red soils, brown soils, and Mediterranean
soils. These soils lack lime and calcium as do the forest brown soils.
The population is dense in on the plains. On the contrary, the population is scarce in the
sloping ares in the south and and the areas covered with forests in the southwest and
northwest.
Figure 1: Location map of study area
Some problems emerging from the physical, human living, and economical features of
the research area cause applied geomorphologic problems. While the sloping, destruction of
vegetation, and climate features (heavy rains, etc.) cause erosion around the plains, the
rivers in the plains with less sloping overflow. Because these fields are alluvial fields which
are rich in underground waters they increase the earthquake intensity. In the fields where
the valleys are common and the sloping values are high, there have been eroded fields
through lithologic characters.
Geology
Paleozoik terrain, which is composed of mainly limestone, covers most of the
mountainous areas leading in the southern part of the area. Mesozoic terrain is associated
with sedimentary rocks such as conglomera and sandstone and Kozak granitic pluton.
Terrary: clayev limestone, sand stone and volcanic tuffs, andesites form terriary formation.
Quaterner is prepresented with the alluvial materials.
Geologic Evaluation of the Area
The western part of the Anatolia was exposed to an extensional regime during the
neotectonic period. In that period, some part of the study area was uplifted and depressed
along some of the fault lines so the tectonic basin was formed in which detritic material
accumulated.
The study area is located between the Kaz Mountain and the low-land southern part of
the Marmara Region. During the Mediterranne Period the vertical tectonic movements led to
the hors-graben system. Namely, the gulf of Edremit and the low land of Marmara region fits
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Environment and Culture in the Mediterranean Region
to grabens and Kaz Mountain is the main horst area which abruptly rises in the northern part
of the Edremit Gulf.
During the Miocene Period, the study area covering the eastern part of the Kaz
Mountain was exposed to erosion due to lake levels occupying the lowland areas and as a
result neogene erosional surfaces developed. At the end of the Neogene Period, the study
area again uplifted. Consequently, the river set up on the neogene erosional surfaces cut its
own valley. In other words, the uplifting of the area has caused the rejumation of fluvial
erosion. As a result, dissected erosional surfaces have been converted into plateaus in
appearence.
Geomorphological Units
The research area which has the characteristics of a plateau is composed of strong
rocks and a bit higher than the level of plateaus are categorized under the name of “ High
Lands and Mountains.”
Apart from the high lands and mountains, it is also possible to divide and classify the
plateaus which take the widest part of the research area in terms of the characteristic
features and different structures and lithologic elements. It is even possible to divide them
into smaller categories classifying them under the name of “ Flat and Rough Plateau
Surfaces.”
On the contrary, all the plains and alluvial base flat places that have come into being
as a result of the cavity in plateau have not been taken into the “ Flat and Rough Plateau
Surfces” because of the collectivity of the morphological unit. They have been classified and
explained under the headline of “ Plains and Base Flats.”
Although the upper line of the Kocaçay Valley seems to have a rough and high
topography, it is characterized with the plateaus which take up a large field in the research
area and a flattened and monotonous topography. However, in general, the area draws
attention with diversity of the geomorphologic forms that it includes.
Figure 2: A picture of Madra Valley
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Figure 3: Geologic map of the study area
Figure 4: Geomorphologic units of the study area
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Hiıgh Lands and Mountains
This part in the southwest of the research area includes Madra, Kozgeçit, Çetin,
Mısırtarlası and Haydar streams and the watershed. They are the highest points of the
Madra Mountains. It reaches 1343 m in Maya Hill. There is a high land in İkizce, Kılcılar, and
Büyükyenice villages where the altitudes of the Madra Mountains decrease, which is called
Asar Tepe (816 m).
The highest point is Mount Sabla whose altitudes decrease from Madra Mountain
which is 1110 m high.
Göldede Hill (871 m),which is located on an old volcanic cone on the northeast part
of the mountainous land, stretches through Madra Stream (Kocaçay) and Yahu Stream.
Havran Stream flows into the Aegean Sea and the Kocaçay flows into the Marmara Sea by
means of Manyas Lake and Susurluk Stream. Mount Madra combines with Mount Sap
which is a part of the Kaz Mountains Range by means of a bridge of 550 m length from the
north. This bridge which includes the highway between Balıkesir and Edremit separates the
Aegean Basin and Marmara Basin. Göktepe (937 m) is an important rough place that is a
range of Şap Mountain towards the east.
Plateaus
Gümeli Plateau
The Gümeli plateau, which is in the south-west of the research area, is situated
between Mount Madra in the south and the İvrindi Plateau in the north. The Gümeli Plateau
covers a minor place in comparison with the İvrindi Plateau. However, its average altitude
level is higher than that of the İvrindi Plateau. In terms of the crack of the surface, Gümeli
Plateau has a considerable value over the other.
It makes a high and dominant relief in the north parts of Mount Madra from which the
Kocaçay River originates. The Gümeli Plateau is blocked from the east by the Kurucu
Mountain range. Faults, which have a considerable effect on the formation, also have a
great role in shaping the topographic characters of the Gümeli Plateau.
İvrindi Plateau
The İvrindi Plateau is the second biggest plateau that lies between the “Main
Geomorphologic Units” in the research area. The southern part of the plateau is blocked by
the Kurucu mountains and Kocaçay Valley. İvrindi, Korucu, and Kayapa, which are the
biggest allocation units in the research area, are in this plateau.
The northwest area of the plateau constitutes a big part of the research area. The
Gokçeyazı plain and Ali Demirci plains are located in this area where the altitude levels are
between 250-350m. The Kocaçay Valley loses the characteristics of a valley in the north
northeast of the area.
The Kocabük gorges in the northeast part of the area is a valley that has been formed
by Kocaçay in lime stone belonging to Üst Permien. The most important characteristic
feature of the Kocabük gorges is that it has a meander.
Kocaavşar gorges: Kocaçay forms two meanders in the valley which widen in the north
part of the Kocaavşar gorges and continues into the valley named Kocaavşar.
Plains and Flat Bases
Flat bases and plains, which constitute the main geomorphologic units, cover 80% of
the research area. High fields and mountains constitute a part which is a little smaller than
20% of the research area. The names of the plains and flat bases are as follows: Madra S.
Flat Base, Haydar, Yahu , ( between Büyük Ilıca and Karaçepiş Villages), Kobaklar,
Arpacık , Taşotluk, Kantar, Salkım Dadalar streams Flat Bases, İvrindi Plain, Gökçeyazı
Plain, Kocaavşar Flat Base, and the Alidemirci Plain.
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Figure 6: A picture of the Ivrindi Plain
Geomorphologic Evoluation
The neogene basin in the upper part of the Kocaçay River was formed by the vertical
tectonic movements in the Oligocene-Miyogene period.
The plateau surfaces in the surroundings of the Ivrindi and Gökçeyazı plain were
uplifted. During the Lower Tertiary Period, notably lower Miocene, the volcanic eruption
began. The pre-neogene terrains are found in the Gümeli and Ivrindi Plateaus covered by
the volcanic material composed of andesits, dasits, and tuffs.
The basins, which were formed in the Oligo-Miogene, were mostly occupied by
Neogen Lake in which volcanic and sedimentary material was accumulated by fluvial
processes. Fluvial depositional processes continued at the end of the Lower Pliocene.
As a consequence, erosional and depositional processes led to the formation of
erosional surfaces in the south, west, and eastern part of the area.
Second erosional surfaces belonging to Pliocene are seen on the plateau surfaces.
Gümeli and Ivrindi plateaus led to the erosion of the Miocene erosional surfaces. For this
reason, the spreading area of the Miocene erosional surfaces decreased due to the removal
of the Miogene surfaces. The uplifting of the plateau surfaces occurred during the Pliocene
Period. Pleistocene has caused the rejuvenation of fluvial erosion. For this reason, the
streams cut their own valleys and the alluvial deposit in the depression has started to be
removed by the rejuvenation of fluvial process.
The formation of deep gorges in the Kocaçay, Kocabük, and Kocaavşar streams is
related to the incursion of the river valley.
It can be stated, that the tectonic movements are responsible for the erosional and
depositional surfaces in the study area. Miocene erosional surfaces were developed
according to the base level of Miocene Lake. Pliocene erosional surfaces were formed in
accordance to the tectonic depression in which alluvial plains are found. The rejuvenation of
the fluvial process that controlled tectonic movements, caused the superimposition and
antecedents events. The streams established on the sedimentary formation deeply cut their
own valley so that the pre-Neogene formation is outcropped along the valleys in some
places.
The uplifting of the area is responsible for the formation of the deep antecedent valley.
The terraces occurring along the valley indicate the lowering of the base levels in
accordance with the tectonic activities.
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Conclusion
The upper part of Kocaçay valley has polycyclic topographic shapes with discordant
cover. The relief shapes are closely associated with lithology and structure dominant relief
shape is plateau. The topography which is dominant in the research area is young because it
is cracked and broken. As of today, the river network which is made out of Kocaçay and its
branch, was formed in Pliosen. To date, it has maintained its position in spite of some
captures.
It can be said that the topographic discordance came into being as a result of the Alp
tectonic movements. It can also be said that this situation originates from the traces,
embedded meanders, and superimposed gorges that have come into being as a result of the
deep erosion of the streams that are the evidence of the young tectonic. The surface of the
erosion is seen as the main relief element. Volcanism has come into being in a definite
amount and it is the consequence of the Third Period. Carstic formations are represented by
lapya which are micro topographic formations.
The fluvial erosion period in the upper part of the Kocaçay valley is a wide valley on
the surface of which is covered with breaks, which indicate the valley is young.
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