Rasho Rashev Introduction Рашо Рашев Увод н и дум и Christina Angelova, Mark. Stefanovich Henrieta Todorova Христина Ангелова, Марк Стефанович Хенриета Тодорова Кратка биография

As briefly summarized above, there are a number of discrepancies between Thrace and Northwestern Anatolia, two neighboring régions located on either side of a small land locked sea the Sea of Marmara. It is evident that some of these discrepancies are due to lack of research, mainly as in the case of Eastern Thrace. Some inconsistency between territories, may find ex-planations on cultural grounds, even though it is yet too early to formulate one. However, there are some facts that are difficult to explain with the présent stand of our knowledge. Here we will try to draw attention to two of such prob-lems; being neither a geologist ñor a geomor-phologist by profession, what we will connote as a solution, should be considered as a provoca­tion to stimulate further interest on these issues by those who are experts.

1) The distribution of coastal Bronze Age sites around the Sea of Mármara is very stränge (see Fig. 5). All through the Northern coast of Marmara, from the Westernmost tip of the Geli-bolu península, up to Istanbul, on every location suitable for habitation, there is an Early Bronze Age settlement. The saine pattern can be seen on the Anatolian side of the Sea of Marmara, from Çanakkale up to Kapidag península. This is evidently a pattern that is strongly indicative of intensive utilization of maritime resources. How­ever, to the east of the Kapidag península, in the entire extend of Southeastern Marmara, not a single Bronze Age site has been recorded. It may be argued that this is a resuit of survey bias; however, in the parts of this coastal strip where oui' surface cover was rallier intensive. We spe­cificali)' searched locations that would in other parts of Marmara, would definitely have yielded a Bronze Age site, but recovered nothing.

b) Not a single Bronze Age sherd have been recovered on the Bosporus. Considering the présence of numerous Bronze Age sites along the Dardanelles, this is very stränge. Here, it may also be argued that Istanbul ibeing a vast metrópolis for over a millennium, might have destroyed all prehistoric sites. However, most of the areas around the Bosporus were void of intensive Settlements during the Byzantine and Ottoman periods, and when we surveyed the région, a number of Paleolithic sites were still available on the surface. Moreover, in spite of the intensive building activity that took place around the Bosporus during the last decade, not a single prehistoric sherd has been repon­ed.

c) In the Eastern part of the Marmara re­gión, the distribution of Bronze Age sites are also rather peculiar. Coming from the South, all the way up to the Iznik basili, and includ-ing this area, there are numerous Bronze Age sites, most of them being sizeable mounds, and all of them yielding lypical Anatolian material. However, on the large terrain lying between the Iznik Lake and the Black Sea no Bronze-Age sites, neither small or big, have ever been recorded. More specifically, the rieh alluvial plains likc the basin of the Sapanca Lake, the catchment of the Gulf of Izmit, the alluvial plain of Adapazari, the tenaces along the delta of the Sakarya river etc. are all void of Bronze Age habitation. Neither there are any Bronze Age sites known from east of Istanbul, ali the way up to Sakarya.

Accordi ngly the présent évidence implies that the lake of Iznik constitutes the Northern limit of Anatolian Bronze Age cultures, and then there is an enormous territory void of any habitation. Considering the présence of several large Bronze Age mounds around the Iznik lake, the lack of sites around Sapanca lake, ex-actly a similar setting and located only 50 km to the North is very difficult to conceive.

d) On the Anatolian side, just to the north of Kapidag península which constitutes the eastern limit of coastal Bronze Age sites, a submerged mound lias been recorded by the small island of Av§a. This site, named as the Manastir Mevkii, is a considerable mound, revealing a complete range of cultural horizons between Kumtepe Ib and Troy VII b2. The site is panially visible on the shore of the island, but extends under the sea up to the depth of 10 m, where a Bronze Age cemetery has also been recovered.

Considering the range of sea level changes during the late Holocene, it seems evident that the présence of this submerged site is related to local tectonics and not to eustatic events.

e) The présence of submerged Bronze Age sites along the Bulgarian coast of the Black Sea présents the most difficult problem to explain. The number of recordecl submerged sites are now over 10, and their number seems to be in-creasing almost every year. Geographically they are dispersed through the entire extent of Bul-garian territory, from Varna to Sozopol. Most of the sites are located between 6 to 8 meters below the présent level of the Black Sea; how-ever, there are also some claims of sites at lower depth, most of the sites Cluster between 5 to 8 meters. As no site could have existed exactly on by the shore, and as most sites are located on small promontories, with some justification the Bronze Age level ofthe Black Sea can be placed at least to minus 10 meters.

The problem is to find an acceptable ex-planation to how ali of these coastal sites could have been submerged. Almost unanimously, re­ports concerning these sites excludes the pos-sibility of tectonic or epirogenic movements and relate this event to a régression phase of the Black Sea. However, in the publications of these submerged sites, we never carne through an attempt in trying to correlate this régression ofthe Black Sea with the globular sea level fluc­tuation curves. To the best of our knowledge, there is no consensus on the sea level fluctua­tions during the late Holocene, however, the maximum estimâtes never exceed plus or mi­nus 3 meters (Masters/Flemmino 1983; Kayan 1988) from the présent levels. Thus it remains to be explained how a régression of the Black Sea of over a range of 10 meters could have hap-pened, at a time when there is no record of such a significant change in worldwide sea levels.

Accordingly, if the Black Sea was connect­ed to the worldwide sea systenis, that is if the Bosporus was existing, then ali over the océans, one has to consider that the sea level was 10 me­ters below its présent level during the Bronze Age; as this seems impossible, than the next possible solution would be to consider Black Sea as being isolated from the Marinara during the 3rd and 2nd Millennium B.C. One other possi­ble solution, tectonic movements, seems anyhow to be rejected by ali.

A Controversial Solution: An Alternative Bosporus

Any major change in the levels, either ofthe océans, or of the other seas, is the conséquence of major climatic fluctuations. Accordingly, such changes occur at times of global warming or cooling, and having an impact in ali littoral ar-eas of the world. The last major marine régres­sion taking place at the time of the last maxi­mum phase of the Würm glaciation, is dated to about 16 000 BC, when the level ofthe sea was 100-120 m lower than of présent. Even though there is some dispute on the exact dates and on the speed of the transgression that followed Würm maximum, there is a general consensus that velocity of the rise in sea levels was rather rapid until 5 000 BC, and from that time on, there were only some minor fluctuations.

Black Sea and the Sea of Marinara are two interconnected inner seas, linked to the world­wide ocean system by only narrow, long and relatively shallow straits. Accordingly, even minor climatic fluctuations, or changes in the worldwide sea levels, provokes exaggerated con­séquences in the closed basins of Marinara and Black Sea. Furthermore, at certain occasions this system becomes further complicateci by be­ing connected to the Caspian Sea

The water exchange between the Black Sea and the Sea of Marmara is a unique case, as the density of their water masses is significantly dif­férent from each other. Large rivers, such as Danube, Dniyepr and Don drain almost ali of the surface water of Central and Eastern Eu­rope into the Black Sea; thus it receives large masses of fresh and cold water. On the other hand, the Sea of Marmara receive highly sa­line warm waters from the Aegean through the Dardanelles. Accordingly the brackish waters of Black Sea is much lighter than that of Marma­ra, and at présent the Black Sea has an excess input of water which almost completely fills up the Bosporus. Actually as the water discharge ofthe Black Sea is little more than the carrying capacity of this narrow and shallow strait, the présent level of the Black Sea being consider-ably higher than that of Marmara.

This complicateci system has some rather complex conséquences: under certain of water masses according to their density and thus pre-venting vertical circulation of oxygen. At présent the Black sea is under such conditions; the density stratification of its waters prevent dis-solved oxygen to reach lower élévations result­ing in anoxie conditions and to the formation of sapropels (see diagrams in Özdogan 1985a, fig. 5.c; Stanley/Blanpied 1980, fig. 2), analysis of the deep sea cores indicate that Marmara had lived similar conditions during the last glacial period (Stanley/Blanpied 1980).

Accordingly, even a minute change in the system, either eustatic change of global sea lev­éis, or due to water input of the Black Sea from river drainage has considerable cffects on:

a) Whether or not saline waters can pass through the Bosporus

b) Marine ecology of Marmara and Black Sea are very unstable and are apt to go through radical changes.

How this system reacted to the radical chang­es that took place in the globular sea levéis dur­ing the last glacial period, is far too complicated to be dealt within the scope of this paper. A sim-plistic overview of this system have already been published elsewhere (Özdogan 1985a; Meriç et al. 1990, 107-111) and, here, for réminiscence, four synoptic charts (Figs. 1-4) have been ap-pended on this issue.

It is clear that somewhere around 7 000 B.C. the Sea of Marmara was already reeeiving both saline waters from the Aegean and fresh waters from the Black Sea. When we had formulated the above mentioned model, we had taken as granted that the contact between Black Sea and Marmara was through Bosporus (figs. 2, 3). However, even then, it was clearly evident from the bottoni sédiments of both Marmara and Black Sea that the présent conditions were established only by the First Millennium BC (Özdogan 1985a, 155). Since then, there has been considerable amount of new data available (Meriç et al. 1990; Deuer 1972; Kaplin et al. 1993) all of which clearly indicate that between the sixth and first Millennium BC, the environ­mental conditions of Marmara and Black Sea were not stable, and there were alternating short facies or épisodes and that the présent level of salinity was firmly established only by the first Millennium BC.

Références

Boer 1994

J. Bof.r. Computer Aided Reconstruction of Un­derwater Sites, Sozopol 1990: A Test-case. -In: M.

211

Besides these unstable marine conditions, archaeological évidence as well as the geomor-phological studies imply that there were signifi-cant changes in the level of the Black Sea be­tween the 6th and Ist Millennium BC (Orachev 1990). Archaeological évidence from Bulgaria and Romania strongly suggests that the Black Sea was recession from the beginning of the 4th Millennium up to, at least beginning of the 2nd.

It ail concludes that the water discharge be­tween the Black Sea and the Marmara, which was already established during the 6th Millen­nium, must have been interrupted at an uncer-tain point during the 4th Millennium. Some-time by the beginning of the Ist Millennium BC, a new connection must have taken place. We are conscious of the fact that this assump-tion will be considered as being far fetched by geomorphologists; however, than, a more con-vincing explanation should be presented to ex-plain the archaeological évidence of submerged Bronze Age sites in the Black Sea.

Paleological évidence shows that, at least during the early Holocene, prior to the for­mation of the Sakarya Delta, the discharge of the Black Sea was through this dépression. We might surmise that during the 4th Millennium, at a time when there was less input of water into the Black Sea basin, extensive silting as weil as rapid built up of the Sakarya delta, possi-bly blocked this channel, in the sanie manner as the Manych channel between the Caspian and Black Sea was silted. What happened later is rather speculative, but a tectonic movement by the beginning of the Ist Millennium could have resulted in over flooding of the Marmara through the présent valley of the Bosporus into the Black Sea.