بررسی و بازسازی تکنیک‌های پخت سفال خاکستری طی هزارۀ سوم تا اول قبل‌ازمیلاد در نواحی شرقی زاگرس‌مرکزی

دو گونۀ شاخص از داده های فرهنگی مربوط به نواحی شرقی زاگرس مرکزی، سفال خاکستری یانیقی مربوط به عصر مفرغ قدیم (هزارۀ سوم قبل ازمیلاد) و سفال خاکستری عصر آهن (هزارۀ دوم و اول قبل ازمیلاد) هستند که شناسایی، بررسی و بازسازی تکنیک پخت این دو گونۀ سفال در پژوهش پیش رو، مورد تجزیه و تحلیل قرار خواهد گرفت. هدف اصلی پژوهش، بازسازی شرایط مشابه پخت این دو گونه بوده که با استفاده از روش های باستان شناسی تجربی و بازسازی عملی و کوره های سنتی محقق گردیده است.  پرسش های پژوهش عبارتنداز: 1. سفال خاکستری به واسطۀ قرار گرفتن در معرض حرارت مستقیم  به سفال خاکستری تبدیل شده یا  این که در فرآیند پخت و احیاء به سفال خاکستری تبدیل می شود؟ 2. مهم ترین عامل تفاوت دو نوع سفال خاکستری عصر مفرغ و عصر آهن در چیست؟ در این مسیر با تکیه بر داده های باستانی و مقایسۀ آن با نمونه های بازسازی شده، به شباهت ها و تفاوت های تکنیکی موجود پرداخته شده است؛ سپس، به بازسازی 2 نمونه از هر یک سفال های خاکستری عصر مفرغ و عصر آهن مبادرت ورزیده و نمونه هایی تولید شده و با بازسازی کوره هایی سنتی که از امکانات امروزی آزمایشگاهی و وسایل دقیق اندازه گیری دما بهره می برد، در معرض حرارت قرار گرفته و در فرآیند پخت و احیاء مورد آزمون و خطا قرار گرفته اند. با نتایج حاصله از آزمون خطای روش مذبور، در انتها می توان چنین نتیجه گرفت که پخت به روش احیاء و رنگ خاکستری حاصله، مهم ترین شاخصۀ مشترک تفاوت سفال خاکستری با دیگر گونه هاست. نوع تکنیک پخت و معماری ساختمان کوره، مهم ترین عامل در تفاوت دو نوع سفال خاکستری عصر مفرغ و عصر آهن است. آن چه مسلم است، با تکامل ساختمان کوره ها، حرارت تولید شده از حدود 700 درجۀ سانتی گراد در سفال خاکستری یانیقی عصر مفرغ، به حدود 1000درجۀ سانتی گراد، در نمونه های عصر آهنی افزایش یافته و باعث بالاتر رفتن کیفیت پخت و همچنین، احیای مناسب و کامل سفالینه ها شده است. مقایسۀ عملی نمونه های بازسازی شده، انطباق کامل مشخصات آن ها را، با نمونه های باستانی (تپه پیسا، تپه توشمالان و تپه احمدآباد) نشان داده و هم چنین از راز تولید این دو گونۀ شاخص سفال خاکستری پرده برداشته است.

Experimental Archaeology; Investigating and Reconstructing Gray Pottery Firing Techniques During the Third Millennium B.C. Until the First B.C. in the Eastern Regions of Central Zagros

AbstractThe two most prominent types of material cultures in eastern Zagros are Bronze Age black burnished pottery (3rd millennium BC) and grey Iron Age pottery (second and first millennium BC) that were dog out during archaeological expeditions are being investigated and reconstructed. The technique of firing these two types of pottery will be analyzed in the present study. The main objective of this research was to reconstruct the similar conditions and techniques of these two pottery class using experimental archaeological methods and practical reconstruction of traditional kilns. Along this route, the technical similarities and differences are discussed, relying on archaeological data and comparing it with reconstructed samples. In this regard, two samples of each of the Bronze Age and Iron Age potteries were reconstructed and samples were produced and refurbished by traditional kiln that utilize modern laboratory facilities and precise temperaturemeasuring devices and are heated in the firing process. The results of the try and error tests indicated that baking with chemical reduction and emergence of gray color is the most important common feature of difference of gray pottery with other pottery assemblages. The firing technique and the structure of the kilns are the most important factors in distinguishing the two types of bronze age and iron age pottery assemblages. What is certain is that with the evolution of the furnace structure, the heat generated from about 700 ° C in the gray Yanniq period of the Bronze Age has increased to about 1000 ° C in the Iron Age specimens, resulting in a higher firing quality as well as a complete and complete chemical reduction of the vessels. Practical comparison of the reconstructed samples showed complete conformity of their characteristics with the ancient specimens (Pisa Tepe, Tushmalan Tepe and Ahmadabad Tepe) and also revealed the secret of producing these two species of gray pottery.Keywords: Eastern Zagros Central Regions, Bronze Age Pottery, Iron Age Gray Pottery, Experimental Archeology, Kiln, Firing and Reduction.IntroductionIn modern archeology, the scientific question is not what we know, but how we know it. This point of view is one of the most important and at the same time the simplest modern archeological approach to past phenomena (Alizadeh, 2004: 91). Therefore, the idea of reconstructing the conditions and the environment in analogy with what was reported in the reports and data was presented. In response to such ambiguities, it can be said that using more modern methods in research such as “experimental archeology” will increase the accuracy of the premises. Early sections of this study have followed up on existing data and library studies of past sources and reports; therefore, in the next section, reconstructing the conditions and environment consistent with the information provided, has been the author’s main goal. In this section, the “kiln making” and the experience of firing the pottery in these kilns were practically achieved, leading to new information on the evolution of the gray pottery production; Proved the assumptions to be true, so that by producing products that were quite similar to ancient data, the key role of the resuscitation process in the firing process and the important role of kiln design and structure in the specific type of firing were demonstrated However, in some sources (Majidzadeh, 1370: 97), general references to the reasons for the pottery being grayed out as interfering with elements such as oxygen, iron, and carbon, and in other research, the reduction process was the main reason ( Kambakhshfard, 2010: 296). Finally, it can be added that according to the comparisons and studies of the samples, the firing of the Iron Age gray pottery somehow evolved into conscious firing methods during the first millennium BC. Although in the early Bronze Age achieved to somehow the technique of reduction firing, but only in Iron Age pottery assembladges, the correct pottery reduction firing can be clearly seen.Discussion After the pottery kiln reconstruction operation and the success of the production of the specimens, only by a very simple comparison, the accuracy of the existing probabilities, which were the unknowns of the equation, can be easily ascertained; however, accurate and scientific recordings of the work confirmed these results. Based on these empirical findings for the Bronze Age gray pottery, although previous findings indicate that the potter accessed the firing process may be regenerated, it is due to the amount of carbon accumulated in the samples (carbonization) that is due to its proximity to heavy smoke and firewood. It can be said it was still not possible to control precisely the firing conditions by the potters.According to existing reports and objective observations of the Bronze Age pottery assemblages, such pottery has much thicker bodies than the gray Iron Age pottery, and empirical indications indicate lower firing temperatures; There are some other features that have been ignored because of their relevance to the subject of this study, that is, firing techniques. As for its firing technique, most of the existing documents refer to the possibility of a ditched type kilns, which is not farfetched from the evidence.Reconstruction of the firing conditions of the Bronze Age pottery indicated that the kiln was probably a smallsize oven shaped hole that provided a relatively primitive chamber for controlling fire and firing in the vicinity of heavy smoke from firewood and fuel. Reconstructed furnace firing sector were able to provide similar conditions for ovenkilns. In this oven shape kiln, pottery was quite similar to the Bronze Age specimens, especially the Yaniqe or Godin IV pottery, but due to physical limitations and initial quality and reduction facilities, they were never comparable to those found in the Iron Age.In fact, despite efforts to create optimum conditions, these types of kilns are not capable of achieving a higher quality product such as gray ceramics of the Iron Age, even though due to the excessive energy loss of the maximum heat produced in the oven by about 700 Centigrade did not exceed that production of higher quality pottery in these conditions is almost unlikely.As the kiln construction techniques expands and evolves, the reconstituted kiln will eventually move closer to the plan of the kilns in the Iron Age, and after a complete overhaul, the result also confirms this claim. In this kiln, reasons such as the separation of the firing chamber, the dominance of proper flame allocation to the vessels, the closure of the pipes and the noncollision of the pipes with the air, made it easier to obtain the appropriate chemical reduction conditions.In fact, the gray color of the potteries reconstituted with the conditions of the Iron Age kilns are mostly due to the correct reduction and dependence of the carbon chemical interactions and the consumption and replacement of the oxygen present in the composite iron oxide in the ceramic body soil. The technical differences in these two species, which are mainly due to differences in the structure of the kiln structure, are evident in the firing quality of the bodies and the difference in the intensity of carbon accumulation and the color difference between the surface and the body depth.Conclusion After examining the documentation available in the time and location of interested research subject, it can be said that the gray pottery has two major variations, both of which have significant differences in terms of time of occurrence, originating culture, and specific production and reduction techniques. In terms of firing technique characteristics, it can be said that the only similarity between these two cultural products is the presence of a “different gray color” in the body of both types of pottery, which has brought them closer together because of the differences in the characteristics of the other species.The characteristics of the Early Bronze Age gray pottery that distinguishes it from the Iron Age gray pottery lie in the presence of two main factors, namely the type of kilns and the pottery body features. According to the comparison and examination of samples, firing gray pottery assembladges of the Iron Age somehow evolves conscious firing methods and only in the examples of the Iron Age pottery can a complete and correct chemical reduction of a pottery be clearly seen.In fact, both of these types of potteries are common in creating an atmosphere of chemical reduction in firing, both of which are interesting in their quality and type of performance, which can be attributed to the progressive evolution of the kiln structure and the facilities and knowledge necessary for its construction and observance for centuries.