Yenikapı kazı buluntularındaki bazı arkeolojik hayvan kemiklerinin nükleer tekniklerle incelenmesi

Abstract

2004 yılında ulaşımın iyileştirilmesi, alternatif yollar oluşturulması ve toplu taşımanın geliştirilmesi amacıyla başlanan Marmaray ve Yenikapı projeleri inşaatları sırasında Neolitik Çağ, Erken Bizans ve Bizans dönemlerine ait arkeolojik buluntulara rastlanmıştır. 52.000 m2'lik alanda yürütülen çalışmada bulunan arkeolojik buluntular tarihin bilinmeyen karanlık yüzüne ışık tutmaya yardımcı olacaktır.Bu çalışmada, Yenikapı Metro ve Marmaray kazılarında bulunan Neolitik Çağ, Erken Bizans ve Bizans dönemlerine ait hayvan kemikleri incelenmiştir. EDXRF yöntemi ile kemiklerdeki Al, Ca, K, Mg, Na, P ve Si elementlerinin konsantrasyonları analiz edilmiştir. Elde edilen sonuçlar dönemler arası ve günümüz hayvan kemiklerindeki konsantrasyonlar ile kıyaslanarak beslenme alışkanlıkları, kemiklerin fiziksel özellikleri, hastalık olasılıkları ile ilgili dönem karakterizasyonu yapılmıştır. Buluntuların elementel bileşimleri, buluntu türleri arasında karşılaştırma yapmak üzere istatistiksel analize tabi tutulmuştur.Neolitik Çağ ve Erken Bizans dönemlerine ait hayvan kemiklerinin elementel konsantrasyonları karşılaştırıldığında, Neolitik Çağdan Erken Bizans dönemine geçiş sürecinde kemiklerdeki Ca, K, Mg, Na, P elementlerinin konsantrasyonu artarken; Al ve Si elementlerinin konsantrasyonunun azaldığı gözlenmiştir. Erken Bizans ve Bizans dönemlerine ait hayvan kemiklerinin elementel konsantrasyonları karşılaştırıldığında ise, Erken Bizans döneminden Bizans dönemine geçiş sürecinde kemiklerde Si konsantrasyonu artarken; Al, Ca, K, Mg, Na ve P konsantrasyonunda azalma olduğu gözlenmiştir. Elde edilen sonuçlara göre, Ca/P oranının benzer olması sebebiyle incelenen hayvan kemiklerindeki kemik oluşumunun günümüz hayvan kemikleri ile benzer olduğu tahmin edilmektedir. Element bileşimlerine göre istatistiksel analize tabi tutulan buluntular hiyerarşik kümeleme analizi (HCA) ile benzerliklerine göre gruplandırılmıştır. Minitab 17.0 yazılımından yararlanarak örneklerin parametrik ya da nonparametrik olduğu Kruskal-Wallis testi ile belirlenmiştir. Konuyla ilgili az sayıda çalışma olduğu gözönüne alınarak, bu çalışmanın, Yenikapı Metro ve Marmaray projeleri arkeolojik kazılarındaki Neolitik Çağ, Erken Bizans ve Bizans dönemlerine ait arkeolojik hayvan kemik buluntularını laboratuvar incelemeleri ve istatistiksel analizlerle destekleyerek İstanbul'un binlerce yıl önceki merak uyandıran tarihi ve hayvan buluntuları ile ilgili yapılacak arkeolojik çalışmalara hizmet edecek çalışmalardan biri olacağı düşünülmektedir.

Istanbul is known as a rich cultural and historical capital with its old stories. After the first known settlement that began with Greek migrations, Istanbul was the capital of the Roman Empire, the Byzantine Empire and the Ottoman Empire which are the largest empires in history. In order to improve transportation, create alternative roads and enlarge public tranportation, Marmaray Project and Yenikapı Subway Project constructions were started in 2004.During the construction of Yenikapı Subway station excavations, some archaeological remains were found. The archaeological findings found during construction disrupted the excavation works, sometimes the routes in the project were changed and even in some cases the works were completely stopped. By decreasing the altitude, discovery of archaeological remains continued and Subway and Marmaray project excavations were converted into archaeological excavations which is placed in 58.000 m2 areas under the supervision of the Directorate of Archeology and Museums. Archaeological findings from Neolithic, Roman, Early Byzantine, Byzantine and Ottoman were found at the end of 4 years excavation. This excavation is seen as a revolution for history of Istanbul by revealing the dark secrets of history and its changing as per eras.Animal bones found among archaeological remains always attract the attention of the archaeologists. Archaeological animal bones shed light on archaeological studies in the context of human behavior and natural processes. The results obtained from animal bones are significant to understand the processes of formation of archaeological features and collect data. In this study, animal bones belonging to Yenikapı Marmaray and Subway excavations were analyzed and dietary habits, physical properties of bones, illness possibilities were characterized and compared with modern animal bones.The first part of obtained samples is dated BC 6500 Neolithic Age. Neolithic Age is known as a first step of civilization and animals were domesticated in this age. For this reason, the examination of animal bones in the Neolithic age has great importance to see the change in the structure of animal bones which have interaction with people when compared to following eras. In Yenikapı excavations, animal bones belonging to Neolithic Age have been discovered from the sea level between 7-9.32 m.The second part of obtained samples which belongs to the Early Byzantine Age is dated back to the 3rd century. Few numbers of samples which are discovered from the sea level between 5.8-7 m were studied to see transition between Neolithic Age and Byzantine Age.The third part of obtained samples which belongs to the Byzantine Age is dated back to between 4-11th centuries and the samples were found in below between 3.02-5.80 m from sea level.In order to analyze the samples and to obtain the correct values, ultrasonic bath cleaning, grinding and weighing process were applied.After the sample preparation, samples were analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray fluorescence spectrometry connected to this microscope to determine their elemental composition. The instrumental conditions in the measurements were set as high vacuum, 100-400-fold magnification, 95% confidence interval, 15 kV operating voltage and 60-200 seconds measurement time. The elemental compositions of the samples were subjected to statistical analysis to compare the species.•Fingerprints of Neolithic Age, Early Byzantine and Byzantine bonesAccording to chemical fingerprints, it is determined that elements of Ca, K, Mg, Na, P are increasing, whereas elements of Al, Si are decreasing from Neolithic Age to Early Byzantine period. From Early Byzantine period to Byzantine period, it is determined that Si element is increasing, whereas Al, Ca, K, Mg, Na, P elements are decreasing.•Change of Ca/P ratioCa/P ratio is agreed by several researches and studies to get information about evaluation of bone formation and diagenesis process. According to the results, it is estimated that the bone formation in the examined animal bones is similar to the modern animal bones due to the similar Ca/P ratio. Hence, it can be predicted that examined bone formation is similar to modern mammalian animals.•Change of Al, Ca, K, Mg, Na, P and Si concentrations in examined animal bonesThe average concentration of Al in healthy bones was reported as 0.813% in studies conducted for the present species of mammals. In comparison with these values, it is observed that the Neolithic, Early Byzantine and Byzantine bones results are below this value. However, it is similar to the amount of Al found in the past studies of mammalian bones. It can be estimated that the concentrations of Al in the examined bones are low and the risk of bone softening or any nerve disease is low in the animals living in these periods.Calcium is not only known as the building block of bones, but also plays a role in the functioning of muscles and body functions. Considering the Ca concentration in the examined archaeological animal bones, the bones of animals living in this period can be interpreted as being strong and healthy.Considering the concentration of K determined in the examined animal bones, it can be estimated that the risk of bone fragility in animals living in Neolithic Age, Early Byzantine and Byzantine periods are similar, but the risk of fragility in the jaw-tooth bones from the Byzantine period is higher.Considering that the Mg concentration in the examined Early Byzantine animal bones are much higher than Neolithic and Byzantine periods, it can be interpreted that the animals living in the Early Byzantine period have stronger nervous system, muscle system and bones. Furthermore, it can be estimated that the risk of osteoporosis in Neolithic and Byzantine animals are higher than Early Byzantine period.Na concentration in the animal bones of the Early Byzantine period was higher than the Neolithic Age and Early Byzantine period, it can be predicted that the acid-base balance of the animals living in Early Byzantine period was better than the other examined periods.The phosphorus concentration in the animal bones of the Neolithic Age, Early Byzantine and Byzantine periods is similar or higher than that of modern mammalian bones. According to these results, it can be estimated that there was no abnormal P concentration in the animal bones in these periods.The high rate of silicon in the bones of the Neolithic Age leads to the fact that the bones of animals living in Neolithic Age are stronger and more resistant to damage when compared to living animals today.•Statistical AnalysisThe dendrogram graphs used for statistical analysis and the results obtained by clustering were interpreted. According to the periods, clusters were made based on the elemental contents of the sample and their relations with each other were examined and similarities were evaluated.According to the results obtained by the Kruskal-Wallis test, no statistically significant difference was found between the findings in terms of concentration accumulation for each element (p>0.05).This study meets the need for supporting laboratory investigations needed to answer the questions about the archaeological animal bones of the Neolithic Age, Early Byzantine and Byzantine periods found in the archaeological excavations of Yenikapı Metro and Marmaray projects. Therefore, the results obtained are important as it will create a database for further archaeological studies.