Göbekli Tepe: A Brief Description of the Environmental Development in the Surroundings of the UNESCO World Heritage Site

Abstract

This contribution provides a first characterization of the environmental development for the surroundings of the UNESCO World Heritage site of Göbekli Tepe. We base our analyses on a literature review that covers the environmental components of prevailing bedrock and soils, model-and proxy-based climatic development, and vegetation. The spatio-temporal scales that are covered are mainly the Eastern Mediterranean region and the Late Quaternary-whereby special attention is given to available data from the close vicinity of Göbekli Tepe. Information on Late Quaternary geomorphodynamics is largely absent for the environs of Göbekli Tepe, we therefore included remote sensing data, different terrain modeling approaches and field-based geomorphological mapping to gain insights into past process dynamics. The findings indicate that the environmental conditions at Göbekli Tepe during its time of occupation differed significantly from today, showing denser vegetation and a wide spread sediment cover. Different hypotheses are developed that aim to guide future research on environmental changes and their variations during the Late Pleistocene and Holocene. These activities are crucial for a more profound understanding of the environment of the site, its potential perception by humans and therefore for the development of narratives on their landscape creation motives.

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land
Article
Göbekli Tepe: A Brief Description of the Environmental
Development in the Surroundings of the UNESCO
World Heritage Site
Daniel Knitter 1,* , Ricarda Braun 2,3 , Lee Clare 3, Moritz Nykamp 2,* and Brigitta Schütt 2
1Physical Geography, Department of Geography, Christian-Albrechts-Universität zu Kiel,
Ludewig-Meyn-Strasse 14, 24118 Kiel, Germany
2Physical Geography, Institute of Geographical Sciences, Freie Universität Berlin, Malteserstrasse 74-100,
12449 Berlin, Germany; ricarda.braun@fu-berlin.de (R.B.); Brigitta.Schuett@fu-berlin.de (B.S.)
3Orient Department, German Archaeological Institute, Podbielskiallee 69-71, 14195 Berlin, Germany;
lee.clare@dainst.de
*Correspondence: knitter@geographie.uni-kiel.de (D.K.); m.nykamp@fu-berlin.de (M.N.);
Tel.: +49-431-880-2941 (D.K.); +49-30-838-70604 (M.N.)
Received: 5 March 2019; Accepted: 18 April 2019; Published: 24 April 2019


Abstract:
This contribution provides a first characterization of the environmental development for
the surroundings of the UNESCO World Heritage site of Göbekli Tepe. We base our analyses on a
literature review that covers the environmental components of prevailing bedrock and soils, model-
and proxy-based climatic development, and vegetation. The spatio-temporal scales that are covered
are mainly the Eastern Mediterranean region and the Late Quaternary—whereby special attention
is given to available data from the close vicinity of Göbekli Tepe. Information on Late Quaternary
geomorphodynamics is largely absent for the environs of Göbekli Tepe, we therefore included remote
sensing data, different terrain modeling approaches and field-based geomorphological mapping to
gain insights into past process dynamics. The findings indicate that the environmental conditions
at Göbekli Tepe during its time of occupation differed significantly from today, showing denser
vegetation and a wide spread sediment cover. Different hypotheses are developed that aim to guide
future research on environmental changes and their variations during the Late Pleistocene and
Holocene. These activities are crucial for a more profound understanding of the environment of the
site, its potential perception by humans and therefore for the development of narratives on their
landscape creation motives.
Keywords:
Pre-Pottery Neolithic; geomorphology; geomorphometry; paleoenvironment; paleoclimate
1. Introduction
Göbekli Tepe stands out as one of the most important prehistoric discoveries of recent decades,
most notably due to its monumental architecture with its monolithic T-shaped pillars, some of
which feature outstanding symbolic imagery, including engravings as well as high and low reliefs.
This imagery provides unprecedented insights into hunter-gatherer belief systems at the transition to
food-producing economies in the Early Holocene (cf. [
1
–
3
]). Göbekli Tepe (Potbelly Hill) was initially
recognized in the early 1960s by a joint Turkish-American archaeological survey team in the frame of
the Prehistoric Research in Southeastern Anatolia project [
4
]. In 1995, fieldwork began under the auspices
of the ¸Sanlıurfa Museum in close collaboration with the German Archaeological Institute (DAI).
Land 2019,8, 72; doi:10.3390/land8040072 www.mdpi.com/journal/land

Land 2019,8, 72 2 of 16
The prehistoric site Göbekli Tepe features an artificial mound (höyük) comprised of archaeological
deposits that accumulated upon a limestone plateau of the Germu¸s mountain range (c. 770 m above sea
level) from the mid-10th to the late-9th millennium BCE (c. 11.5–10 ka BP) [
1
]. This period corresponds
to the early Pre-Pottery Neolithic (PPN), i.e., the Pre-Pottery Neolithic A (PPNA; 9.500–8.700 BCE),
and the Early and early Middle Pre-Pottery Neolithic B (EPPNB-MPPNB; 8.700–8.000 BCE). The nine
hectare large mound is focal point of a newly inscribed UNESCO World Heritage Site. The eight
monumental buildings so far discovered at Göbekli Tepe are labelled A through H in the order
of their discovery. These buildings were multiphase structures with long biographies in excess of
decades, perhaps even centuries [
1
,
5
–
8
]. Based on a presumed absence of domestic buildings and water
sources, Göbekli Tepe was soon interpreted as a solely ritual site and that the associated demands on
hunter-gatherer subsistence economies consequently triggered technological innovations, primarily the
domestication of plants and animals [
2
,
9
–
12
]. At the time this hypothesis was ground-breaking in
that it reversed previous opinions which saw domestication as the prerequiste for the subsequent
emergence of religion. Meanwhile, recent excavations have relativized this statement. Not only is there
now evidence for domestic occupations at the site from its earliest phases, it is likely that settlement
continued unabated into the PPNB [1].
Currently, there is an imbalance between on-site archaeological investigations as described
above and off-site studies dedicated to systematic geographical and geoarchaeological questions that
are yet lacking for the environs of Göbekli Tepe.
1
The integration of Göbekli Tepe in the broader
landscape is a crucial step toward a better understanding of late hunter-gatherer lifeways prior to the
emergence of morphologically domestic plant and animal species. In this contribution we present a
first general environmental characterization of the site and its hinterland. We assess to what extent the
present environmental characteristics are comparable to those of the Early Holocene, thus providing
a starting point for later reconstructions of environmental perception and landscape creation in the
PPN. This study is based on a literature review, map data and analyses of remote sensing data,
including different digital terrain modeling approaches. Furthermore, it integrates the results of
geomorphological mapping and extensive field-inspection.
2. Overview of the Natural Characteristics in the Environs of Göbekli Tepe
Göbekli Tepe is located about 12 km northeast of the modern city of ¸Sanlıurfa. The Urfa region
(Urfa Yöresi) is characterized by a nearly horizontal limestone formation that forms the Urfa plateau
(Urfa Yayla). The research area is a highly homogeneous region which stretches from the northern
arch of the Euphrates (turk. Fırat) in the north and west (Siverek and Birecik Çevresi) to the foot of the
Karaca Da˘g in the east, and up to Syrian-Turkish border in the south ([15,16]; Figure 1).
2.1. Bedrock and Soils
The area is characterized by various limestone and marl formations (Figure 2). The Tektek,
Fatık, and Germu¸s Da ˘gları (mountain ranges)—in the central part of the study area—are built up of
shallow water limestones from the Neogene which feature abundant fractures and karst features [
17
].
Shallow calcisols with massive underlying calcretes developed in the mudflow deposits of the two
fault sides (the Tektek and Fatık Da˘gları) belonging to the Akçakale–Harran graben [18].
1Exceptions are [13,14], though these were limited to conclusions based on pedogenic carbon analysis.

Land 2019,8, 72 3 of 16
Figure 1.
Overview map of the study area with main topographic features and sites as mentioned
in the text (elevation based upon European Digital Elevation Model (EU-DEM), version 1.1, http:
//land.copernicus.eu/pan-european/satellite-derived-products/eu-dem/eu-dem-v1.1/view).
The surface deposits of the Akçakale–Harran Graben, which corresponds to the Harran Ovası
(plain), are Pleistocene clays, sands, and gravels. These undifferentiated sediments cover limestone
and marl deposits of several hundred meter thickness [
19
]. The most common soils of the Harran
Ovası are vertisols with a well-developed Bss-horizon characterized by a smectite content of over 50%
in its clay fraction [20].
North of Göbekli Tepe, Upper Cretaceous clastic limestone occurs that is superimposed by Upper
Miocene basalt rocks. Basaltic covers are also present as residual patches in the immediate vicinity of
Göbekli Tepe, as well as in the Fatık Da˘gları and in northern parts of the Tektek Da˘gları, upon which
vertisols and cambisols developed [
20
]. The clay fraction of these soils shows particular features of
transformation and neoformation from smectite to palygorskite or kaolinite—the former can be seen
as an indicator for drier climatic conditions with limited processes of desilication, while the latter is
indicative for a wetter climate [20].

Land 2019,8, 72 4 of 16
Figure 2. Chronostratigraphy (a) and Lithology (b) in the environs of Göbekli Tepe (based on [21]).
2.2. Climate
¸Sanlıurfa province is characterized by a semi-arid climate with dry hot summers (mean
temperature in July: 30
◦
C) and cool wet winters (mean temperature in January: 4–5
◦
C) and an annual
average temperature of 18
◦
C (Figure 3). Reliable rainfall occurs in autumn, which can fall as snow in
the winter months; the wet season ends in May. The Harran Ovası has a mean annual precipitation
of 283 mm, while mean annual evaporation can reach up to 1848 mm [
19
]. Orographic effects cause
higher annual precipitation rates in the northern part of the province [22].
Figure 3.
Climate diagram of ¸Sanlıurfa. Arid conditions prevail during summer months (reference
period: 1961–1990; data acquired from https://climexp.knmi.nl/, referring to the World Meteorological
Organization station Urfa, code: 17270 (based on [23])).

Land 2019,8, 72 5 of 16
2.2.1. Model-Based Late Quaternary Climatic Development
PMIP III climate model experiments enable the reconstruction of climatic characteristics in the
wider study area for different time periods (Figure 4). The model results suggest that the area around
Göbekli Tepe in the Last Glacial Maximum (21 ka BP) was characterized by a summer dry, cold climate
(Dsa after Köppen-Geiger). Temperatures increased in the Holocene, leading to a temperate climate
with hot and dry summers (Csa after Köppen-Geiger).
Figure 4.
Climatic characteristics in the wider surroundings of Göbekli Tepe during (
a
) Last Glacial
Maximum (21 ka BP), (
b
) Middle Holocene (6 ka BP), (
c
) Pre-Industrial period (0 ka BP). Data are
derived from climate model experiments (PMIP III), Köppen-Geiger classification conducted by Willmes
et al. (see [
24
] for further details and raw data of classification); (
d
) Modern climate characteristics
based on [
25
]; MAP = mean annual precipitation, MAT = mean annual temperature,
Thot
= temperature
of the hottest month,
Tcold
= temperature of the coldest month,
Tmon10
= number of months where the
temperature is above 10
◦
C,
Psdry
= precipitation of the driest month in summer,
Pwdry
= precipitation of
the driest month in winter,
Pswet
= precipitation of the wettest month in summer,
Pwwet
= precipitation
of the wettest month in winter,
Pthreshol d
= varies according to the following rules (if 70% of MAP occurs
in winter then
Pthreshol d
= 2
∗MAT
, if 70% of MAP occurs in summer then
Pthreshol d
= 2
∗MAT +
28,
otherwise
Pthreshol d
= 2
∗MAT +
14). Summer (winter) is defined as the warmer (cooler) six month
period of October, November, December, January, February, March, and April, Mai, June, July, August,
September (after [26]).
2.2.2. Proxy-Based Late Quaternary Climatic Development
Since paleoclimate proxies are still lacking for the immediate surroundings of Göbekli Tepe,
reconstruction of Late Pleistocene to Early Holocene climate development are compiled for the Eastern
Mediterranean region based on case studies (Table 1) and reviews [
27
–
31
]. Uncertainties relating to

Land 2019,8, 72 6 of 16
the absolute dating of paleoclimate records, climatic and environmental changes in the wider Eastern
Mediterranean region appear to occur synchronously between c. 16–9 ka BP [
28
]. All proxy records
indicate changed climatic conditions, however their timing and local occurrence is heterogeneous and
show no general pattern.
The time period 25–17 ka BP is characterized by colder temperatures (12–16
◦
C) and less
precipitation (300–450 mm) compared to present-day records [
32
]. Coldest (c. 12
◦
C) and driest (c.
250 mm) conditions prevailed between c. 25–19 ka BP [
33
], with increases in temperature (14.5–18.5
◦
C)
and precipitation (375–540 mm) becoming visible between 17–15 ka BP [
32
] but remaining below
present-day conditions. A cold and relatively wet period during the Late Glacial (c. 17.3–14.8 ka BP)
is evident in the data from Lake Hazar in central Anatolia [
34
], though records from Sofular Cave
indicate cooler and drier conditions for northern Anatolia until 14.6 ka BP [35].
At the onset of the Bølling-Allerød (c. 14.6 ka BP) temperatures and moisture increased within
a few decades to centuries (until 12.5 ka BP [
34
,
35
]), thus corresponding with a period of maximum
humidity during the Late Glacial (14.9–13.5 ka BP [
36
]). In the later part of the Bølling-Allerød
(13.5–12.9 ka BP) conditions became drier [
36
]. The subsequent Younger Dryas coincides with highest
levels of aridity (c. 12.5–11.7 ka BP) and is consistently referred to as a cool and extremely dry
period [
34
–
37
]. In contrast, a general trend toward increasing precipitation (680–850 mm) is reported
for central Israel in the period 12–10 ka BP [32].
The end of the Younger Dryas is marked by a rapid and substantial increase in temperature
and moisture [
28
,
38
]. Until 9.5 ka BP temperatures increased, though with gradually decreasing
precipitation [
34
]. According to data from Lake Hazar, maximum precipitation between 10.1–9.3 ka BP
coincides with the Early Holocene [
36
], while at Sofular Cave wettest conditions are dated slightly later
at c. 9.6–5.4 ka BP [
38
]. This is in general agreement with data from central Israel showing increased
precipitation (675–950 mm) between 10–7.0 ka BP, with a peak between 8.5–7.0 ka BP [
33
], also with the
potential occurrence of heavy rainstorms throughout the year [
32
]. Although climate conditions in the
Eastern Mediterranean during the Early Holocene were warmer and wetter than in the Late Glacial,
short periods of rapid climate change have been identified in numerous paleoclimate proxy records
(also at Lake Nar [37] and Soreq Cave [32,33]) at c. 10.2 ka BP, 9.3 ka BP and 8.6 ka BP [27,29–31].
Table 1. Paleoclimatic and environmental proxies, their locations and regional context.
Location Region Proxy Reference
Soreq Cave C Israel stable δ18Oand δ13 Cisotopes from speleothems [32,33,39]
Lake Hazar C Anatolia µ-XRF multi element data and δ18Oand δ13 Cisotopes from ostracods [34,36]
Sofular Cave N Anatolia stable δ18 Oand δ13Cisotopes and 234U/238Uratio from speleothems [35,38]
Lake Nar C Anatolia stable δ18Oand δ13Cisotopes and carbonate mineralogy from limnic sediments [37]
Lake Eski Acıgöl SE Anatolia multi-proxy [40]
2.3. Vegetation
Steppe and arboreal vegetation with
C4
plants, a low plant density, and little soil microbial activity
due to dry climatic conditions prevailed between 50.3 ka BP and 14.6 ka BP [
35
]. The subsequent
Bølling-Allerød, with its increasing temperatures and effective moisture, is characterized by a greater
proportion of
C3
plants and higher soil productivity [
35
]. The dry and cold climatic conditions during
the Younger Dryas again triggered a retreat of mesic forests and the spread of steppic vegetation [
36
].
Comparison of Lake Eski Acıgöl (SE Anatolia) and Lake Van (E Anatolia) records show a rapid
switch from Artemisia-chenopod to grass steppe at the end of the Pleistocene, and the increase and
subsequent decrease of Pistacia during the first half of the Holocene [
40
]. Rössner et al. [
41
] propose
for the research area an oak decrease in the Younger Dryas, replaced by dense stands of annual
grasses. However, a postulated renewed spread of oak woodland in the Early Holocene is not reflected
in the available archaeobotanical data from Göbekli Tepe, where there are high ratios of grasses,
pistachio and almond (cf. [
42
]). Grasses included cereals such as wild einkorn, wild wheat, and wild

Land 2019,8, 72 7 of 16
barley. Furthermore, 90% of charcoal samples from Göbekli Tepe have been identified as pistachio
and almond [
42
]. In summary, botanical remains indicate that a steppe vegetation with stands of
pistachio and almond trees was characteristic of the landscape at Göbekli Tepe at the time of its
settlement. This conclusion is further supported by archaeofaunal analyses which show high ratios of
open grassland inhabitants (e.g., Ovis, Capra, Gazella and Equus) among recovered animal remains [
43
].
Non-arboreal taxa as well as mesic deciduous trees declined sharply in the Eastern Mediterranean
during the climatic aridization after c. 6.5 ka BP [
40
]. First human impact on vegetation becomes
evident between c. 4.5–4.0 ka BP [
40
]. Today, Irano-Turanian steppic vegetation types such as Fabaceae,
Asteraceae, and Poaceae members are widespread [
44
]. However, as a result of intensive cultivation and
animal pasturing the potential natural vegetation in most parts of the region has disappeared [
45
],
e.g., in the area of the Culap Suyu basin and the Harran Ovası (Figure 8d) it has been replaced by
irrigation agriculture.
3. Assessment of Geomorphodynamics and Landform Classification
3.1. Geomorphometric Analyses
The existence time of relief forms and their spatial extent follows approximately a logarithmic
distribution, i.e., large landforms persist for long periods of time, while small landforms are more
transient [
46
]. Accordingly, the application of a modern digital elevation model provides insights
into the general relief characteristics and process dynamics for Göbekli Tepe and its hinterland.
However, small topographic features are not identifiable since these have been either destroyed
by erosion or covered by sediments (Figure 5).
Figure 5.
Small topographic features, like rills, that might have existed during time of occupation
of Göbekli Tepe will be not visible utilizing modern surface information due to their short existence
time; (
a
) Photograph showing sediment filled rills in the headwater area that were exposed by the
construction of an irrigation channel; (
b
) Map of tangential curvature, showing the generally smooth
charater of the slopes, with little traces of rills on the surface.
A digital elevation model (TanDEM-X, 12 m resolution) is used to derive geomorphometric
parameters, each showing complementary features of general topographic characteristics and relief
elements larger than rills or gullies (calculations undertaken with GRASS GIS [47]):
•
Slope, a continuous parameter, is used to show the gradient of the site and its hinterland
(Figure 6a). The highest gradients are mainly present in the areas of upper midslopes adjacent
to the limestone plateaus. With the exception of the more gentle slopes in the area of the basalt
plateau, southwest of Göbekli Tepe, the slopes in its immediate surroundings are very steep.
The rolling hills are characterized by intermediate inclinations, and the undulating and flat plains
towards the east and south show the lowest slope values (cf. Figures 6a and 8a).

Land 2019,8, 72 8 of 16
•
Profile Curvature, a continuous parameter of surface curvature in the direction of gradient [
48
],
is used to identify the nature of steps and breaks in topography e.g., between the plateaus and
the lower lying slopes (Figure 6b). The extended plateau, upon which Göbekli Tepe is located,
is separated from the slope by a pronounced convex break. The convexities decrease toward the
rolling hills and pronounced convex breaks in slope are absent. High concavities are present
along the drainage ways of the low order catchments surrounding Göbekli Tepe and in the basin
to its west and diminish when approaching the flat plains surrounding the archaeological site
(cf. Figures 6b and 8a).
•
Topographic Index, a continuous parameter showing the liability of relief to concentrate water [
49
],
is used to distinguish areas of more concentrated, linear runoff from areas with a more extensive
and less distinct runoff (Figure 6c). It is evident that only the flat basalt plateau southwest of
Göbekli Tepe, as well as the midstream-sections of the first-order streams of the Culap Suyu basin,
show a tendency toward extensive converging flows. The limestone plateaus and the rolling hills,
however, show strongly diverging flows (cf. Figures 6c and 8a).
•
Geomorphons [
50
], a nominal parameter showing different landforms, is used to identify areas
with similar geomorphometric characteristics (Figure 6d). The intense dissection of the limestone
plateaus and the rolling hills is shown by the close proximity of the classes ridge and spur and
the class valley. In contrast, in the direction the undulating plain of the Culap Suyu basin and
the northern Harran Ovası, the distance between the classes ridge and spur and the class valley
increases, thus indicating that the relief of the basin is less structured than the limestone plateaus
and the rolling hills (cf. Figures 6d and 8a).
Since the area is characterized by poorly porous limestones with low infiltration capacity,
precipitation often generates surface runoff which leads to erosion, an important factor in younger
relief development. In order to identify areas most liable to changes in topography triggered by
erosion and deposition, a Unit Stream Power Based Erosion Deposition model (USPED) is applied
which combines the Universal Soil Loss Equation parameters with the upslope contributing area.
Accordingly, the liability of the area to sediment flows is assessed (cf.
[51,52]
). Therefore, erosion and
deposition is computed as change in sediment flow in the direction of steepest slope (Figure 7).
The required factors for the USPED model are created using GRASS GIS [47] and R [53]:2
•
Slope length factor, i.e., a topographic factor mirroring the dependence of erosion on the length as
well as the gradient of the slope, is derived from a digital elevation model.
•
The soil erodibility is influenced by organic matter content, soil texture, its permeability and profile
structure. Due to the absence of extensive and systematic soil survey, we link the soil erodibility
to geological information (Section 2.1 and Figure 2). This is appropriate, since soil types in the
area are strongly determined by bedrock properties. Soil texture characteristics are derived from
representative, published soil profiles: It follows that Chromic Vertisol soil ([
20
], p. 173) is related
to the geological unit alluvium (unit “undifferentiated” in Figure 2), Chromic Ochric Vertisol ([
18
],
p. 114) is related to the basalt regions, Petric calcisol chromic ([
18
], p. 151) is related to limestone
areas, and Cambisol, i.e., Karata¸s soils ([18], p. 114), is related to terrigenous clastics.
•
Since spatially and temporally high-resolution weather and climate information are not available,
Rainfall erositivity, i.e., the kinetic energy of rainfall, is approximated based on climate information
from ¸Sanlıurfa weather station [23] and a modified Fournier’s index [54].
•
The other factors of the erosion model require information on Land-use and soil conversation
measures. They are omitted owing to lack of data.
2
Of course, the model can only be considered as rough estimation since it utilizes modern data as well as simplifying
assumptions concerning substrate and climatic information.

Land 2019,8, 72 9 of 16
Figure 6.
Geomorphometric parameter raster derived from digital elevation model: (
a
) Slope (in percent);
(
b
) profile curvature; (
c
) Topographic Index; (
d
) Geomorphons, numbers correspond to: 1—summit,
2—ridge, 3—shoulder, 4—spur, 5—slope, 6—hollow, 7—footslope, 8—valley, 9—depression.
Figure 7.
Sediment-sinks and sediment-sources at Göbekli Tepe and in its hinterland as derived from a
USPED model.

Land 2019,8, 72 10 of 16
3.2. Geomorphological Mapping
The geomorphological characteristics of Göbekli Tepe and its hinterland are assessed using
detailed geomorphological mapping (after [
55
,
56
]) for the close vicinity of the site (approx. 4 km
radius), combined with extensive field-inspection and photo documentation for the wider hinterland
(approx. 12 km radius). The detailed geomorphological field maps were digitized and cross-checked,
generalized, and extrapolated on the basis of high resolution satellite imagery (<1 m resolution;
DigitalGlobe, Inc., maps.google.com, last accessed 5 October 2018) to provide an overview map
of the general geomorphological units (Figure 8a). The geomorphological units scree slopes and
undulating plains were combined with the terrain form valley from the computed geomorphons and
sedimentological field data to provide an overview of the typical locations of the dominating sediments
(Figure 8a).
3.3. Landform Characterization
The six general landform units identified in the environs of Göbekli Tepe are: limestone plateaus,
basalt plateaus, scree slopes, undulating plains, flat plains, and alluvial plains (Figure 8a).
The limestone plateaus are characterized as outcropping bedded limestone usually showing
mayor scarps at the shoulders and located in upper midslope positions. The mainly flat-lying limestone
plateau areas are mostly lacking sediments [
22
]; locally they show a cover of up to boulder-sized gravels
and patches of a thin soil layer (Figure 8b; [
57
]). According to the erosion-deposition model these areas
show low erosion liability or stable conditions (Figure 7). Downslope of the mayor scarps, usually at
the upper midslopes, the modeled erosion liability is highest (Figure 7). These areas are mostly covered
with gravels of up to boulder size and largely lack a cover of fine sediments (Figure 8b). The sharp
forms that characterize the limestone plateaus are not present in the basalt plateau areas where much
smoother forms dominate (Figure 8a) and largely stable conditions prevail (Figure 7). The basalt
plateaus are densly covered with up to boulder-sized gravels and usually show a considerable soil
cover that is used for arable farming [22] after surface clearance (Figure 8c).
The scree slope unit comprises the midslope sections adjacent to the plateaus and the rolling
limestone hills (Figure 8a). These areas are characterized by sediment covered slopes (Figure 8b).
Erosion liability is usually high to moderate and locally a moderate to high deposition liability occurs
(Figure 7). The sediments that are present on the scree slopes are dominated by gravels with a
considerable amount of fine sediments (Figure 8b) wherein soil formation occurs [22].
The footslopes are characterized by the deposition of slope sediments (Figure 8a) that frequently
exhibit particular depositional structures such as clasts with downslope-dipping long axes. Along the
thalweg the slope sediments are mostly dissected by recurring concentrated overland flows forming
distinct steps. In the erosion-deposition model these conditions are reflected in the frequencies of
adjacent (i.e., in neighboring cells) high erosion and high deposition areas in the thalwegs of the valleys
(Figure 7).
The same pattern is also present further downslope in the areas of the undulating plains (Figure 7),
but with a clear difference in depositional conditions. The sediments along these thalwegs are
characterized by a distinct division of well rounded, fluvially deposited gravels that partially show
normal grading or imbrication and locally redistributed slope sediments (Figure 8a). Soils are usually
thicker than those found on the scree slopes or at footslope positions [22]. The unit of the undulating
plains covers the piedmont area of the rolling hills, i.e., most of the surface of the Culap Suyu basin and
the northern part of the Harran Ovası (Figure 8a,d). Further to the south, the Harran Ovası becomes
increasingly flat (Figure 8a).
In the alluvial plain of the north-south oriented Culap Suyu river, which is located east of Göbekli
Tepe, Late Pleistocene and Holocene alluvial loams are accumulated [
22
]. In the area of the Culap
Suyu basin the alluvial plain tends to be delimited by a marked step toward the undulating plain
(Figure 8d). This step increasingly vanishes in the area of the flat plain of the northern Harran Ovası.
Here, the alluvial plain also widens considerably (Figure 8a).

Land 2019,8, 72 11 of 16
Figure 8.
(
a
) Geomorphological overview map of the wider surroundings of Göbekli Tepe, i.e.,
the northern Harran Ovası and the southern Culap Suyu basin with photo locations of panorama
pictures (
b
–
d
). (
b
) Panorama photograph of the limestone plateau, the areas of the upper midslopes
and the adjacent scree slopes. (
c
) Panorama photograph of the basalt plateau southwest of Göbekli
Tepe showing the boulder-cleared surface and the basalt gravel heaps. (
d
) Panorama photograph of
the Culap Suyu alluvial plain and the adjacent undulating plains in the Culap Suyu basin.

Land 2019,8, 72 12 of 16
4. A Short Description of Göbekli Tepe’s Environment
This review of natural environmental conditions and the analysis of local geomorphodynamics not
only permits a more comprehensive description of the location of Göbekli Tepe, it also shows whether
this location was distinct in terms of its environmental signature. Based on currently available data it
cannot be adequately assessed whether the present-day natural environmental conditions resemble
those prevailing at the time of settlement activity at Göbekli Tepe (11.5–10 ka BP); nevertheless,
different hypotheses can be postulated:
•
We consider that the general characteristics of bedrock and topography around the site are currently
similar to those in the Early Holocene, though changes in the course of the last eleven millennia
cannot be ruled out.
•
The climate conditions have indeed changed in the last c. 25 ka albeit that the magnitude of
variation strongly depends on the datasets used for reconstruction (cf.
Sections 2.2.1 and 2.2.2
).
Generally, paleoclimate proxies suggest that substantially higher precipitation and temperatures
prevailed during the Early Holocene in the Eastern Mediterranean [
28
,
32
–
34
,
36
,
37
].
However, in the absence of reliable paleoclimate archives from the research area these results
cannot be elaborated further, nor can it be verified whether precipitation rates also increased in
the environs of Göbekli Tepe. Nevertheless, the model-based and the proxy-based reconstructions
show that neither glacial nor periglacial conditions have prevailed in the region since at least c.
25 ka BP
, as this would have hampered chemical weathering, soil formation and the development
of a steppe or forest-steppe vegetation. Therefore, we can assume that at least c. 15 ka prior to
the establishment of Göbekli Tepe, the climatic conditions more or less continuously fostered
chemical weathering, soil formation, and the establishment of a vegetation cover.
•
Accordingly, we assume that the limestone plateaus and upper midslopes were covered by loose
material, created by in situ weathered bedrock and characterized by developed soils—fixed by the
roots of the vegetation. This assumption rests on the evidence that agricultural practices such
as arable farming and animal husbandry are not attested at Göbekli Tepe and it can be assumed
that potential disturbances of the persisting steppe-forest [
43
] were minimal. In consequence,
soil erosion and sediment redistribution triggered by human influences were largely absent.
Furthermore sediment transport to the foot slopes, alluvial plains, and streams would have been
negligible. The loose material which we expect to have formed on the plateaus and the sediments
that we expect to have accumulated on the slopes in the Late Pleistocene were likely eroded during
the Holocene due to varying climatic conditions, human impact, or—most likely—a combination
of both. Indications that human activities fostered soil erosion and sediment redistribution are
known from archaeological sites in the area at least since the Bronze Age (cf.
[22,45,57]
). Today,
soil erosion is largely absent at the upper midslopes due to lacking soil cover (cf. Figure 8b)
and erosion features only occasionally occur mid- and downslope. Rills at the footslopes that
are incised in the bedrock are sediment-filled today and prove that linear erosion took place at
a yet unknown time (cf. Figure 5). One possible interpretation of this seemingly contradictory
observation is a scenario in which erosion and deposition alternate, depending on the general
climatic conditions.
•
The present-day climatic conditions would allow a vegetation cover that is comparable to the one
that existed during the settlement period of Göbekli Tepe [
42
,
43
]; however, past and present land
degradation and modern agricultural practices have prevented the development of this potential
natural vegetation cover [
45
]. Animal husbandry, mainly sheep and goat pasture, prohibits the
re-establishment of a steppe like vegetation, especially grasses; arable farming prohibits the
re-establishment of a light steppe “forest”; arboriculture, e.g., olive plantations and afforestation,
prevents the formation of natural steppe. Changes in the hydrological system, as most obvious in
the Harran Ovası and the Culap Suyu basin, in combination with irrigation measures constitute

Land 2019,8, 72 13 of 16
an entirely human-managed agro-landscape that has nothing in common with conditions that
prevailed 100 or 10,000 years ago.
Hence, locally the environmental characteristics around Göbekli Tepe may have changed
considerably in the course of the Late Pleistocene and Holocene. The degree to which such changes
are of importance for the understanding and interpretation of the archaeological site is the objective of
future research.
5. Conclusions
This literature review combined with the results of remote sensing data, digital terrain modeling,
and geomorphological field work represents the first systematic compilation of environmental data
in the surroundings of UNESCO World Heritage Site Göbekli Tepe. Based on this synthesis of the
currently available data, complex landscape dynamics with non-linear consequences on local and
regional scales are attested.
Although the bedrock has remained unchanged at least since the Early Holocene, soil cover and
vegetation have been, among other things, influenced by human activities. Earliest indications for soil
erosion are known from the Bronze Age, however, anthropogenic impacts should not be ruled out for
earlier periods, including the Late Paleolithic and the Neolithic. Accordingly, further field studies and
research focusing on the Late Pleistocene and Early Holocene are crucial not only in the vicinity of
Göbekli Tepe, but also in its wider environs.
In the light of climate and environmental change to have occurred in the last twelve millennia,
a continuous integration of disciplinary results and interdisciplinary research is necessary in order
to provide a more profound understanding of the site and its landscape integration. The present
compilation of environmental data forms the basis for further research on diachronic trends of sediment
dynamics and on changes in landscape perception and creation among prehistoric communities.
Author Contributions:
Conceptualization: D.K., R.B., M.N.; Geomorphometric analysis and modeling: D.K.;
Geomorphological analysis: M.N.; Figures and maps: D.K., R.B., M.N.; Writing—original draft: D.K., R.B.,
M.N.; Writing—reviewing draft: D.K., R.B., M.N., B.S., L.C.; Revise: D.K., R.B., M.N.; Funding Acquisition: B.S.,
L.C., D.K.
Funding:
This research was funded by: Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)
Projekt number 165831460 (The Prehistoric societies of Upper Mesopotamia and their subsistence), 2901391021
(Collaborative Research Center 1266 “Scales of Transformation”).
Acknowledgments:
We wish to thank the General Directorate of Cultural Assets and Museums, Ministry of
Culture and Tourism of Turkey and the ¸Sanlıurfa Museum for making research possible. We are grateful to three
anonymous reviewers whose comments helped to improve this paper.
Conflicts of Interest: The authors declare no conflict of interest.
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