بررسي اوضاع سياسي ـ اقتصادي حكومت اشكانيان در سال هاي 57-2 ق.م. (دوران پادشاهي ارد دوم و فرهاد چهارم) براساس مطالعه ي تركيبات شيميايي سكه هاي نقره با روش آزمايشگاهي PIXE

Studyin the Politico-Economic Condition of Parthians Between the 57-2 B.C, the Kingdom of 2nd Orod and 4th Farhad, Based on the Analysis of Chemical Compounds of Silver Coins Using PIXE Method

باستان‌سنجی ‌یا آركئومتری[1] شاخه‌ای نسبتاً جدید از علم باستان‌شناسی است كه در آن یافته‌های باستانی توسط شیوه‌های مختلفی از روش‌های آزمایشگاهی موردبررسی قرار می‌گیرند. سكه‌های تاریخی، از جمله داده‌های سودمند باستان‌شناسی است. سكه، معیار سودمندی برای شناخت مقیاس‌ها و اوزان در ادوار گذشته به‌شمار می‌رود، حتی با مطالعه‌ی شهرهایی كه سكه در آن‌ها ضرب شده جغرافیای تاریخی آن مناطق را، می‌توان با دقت بیشتری ترسیم و تدوین نمود. در این پژوهش، مجموعه‌ی 15 سكه‌ی نقره متعلق به«اُرُد دوم» و «فرهاد چهارم» (57-2 ق.م.) با استفاده از روش آزمایشگاهی «پیكسی»، مورد طیف سنجی قرار گرفت. این ارزیابی، مبنی‌بر این فرض است كه عناصر نادر موجود در سكه‌ها، به‌ویژه عنصر طلا، می‌توانند به‌عنوان شاخصی برای بررسی تعدد معادن در نظر گرفته شوند؛ هم‌چنین میزان غلظت عناصر، می‌تواند در تحلیل شرایط سیاسی و اقتصادی دوره‌ی مورد مطالعه، سودمند واقع شود. نتایج مطالعات نشان داد كه در دوره اشكانی از معادن متعدد در ضرب سكه‌های نقره استفاده شده است. میزان بالای نقره در سكه‌های اُرُد دوم نسبت به سكه‌های فرهاد چهارم به وضعیت مساعد اقتصادی در دوره‌‌ی این پادشاه اشاره دارد، هم‌چنین نوسانات زیاد در سكه های فرهاد چهارم كه در ضرابخانه‌ی میتردات‌كرت به ضرب رسیده‌اند، در مقایسه با سكه‌های اُرُد دوم كه در ضرابخانه‌های اكباتان و لائودیسه ضرب شده، بیان‌گر تفاوت شرایط سیاسی- اقتصادی مناطق غربی و شرقی كشور، در زمان فرهاد چهارم می‌باشد. [1]. Archeometry  

Archaeo-metry is a relatively new branch of archaeological science in which archaeological finds are examined by different procedures of laboratory methods. The ancient coins are of the very useful archaeological data. Coin is considered as a useful criteria to scales and weights recognition‚ even with the study of cities in which coins are minted‚ historical geography of that region can be drawn more accurate. In this research‚ a collection of 15 silver coins belonging to 2nd Orod and 4th Farhad (57-2 B.C), using PIXE method, spectroscopy has been done. PIXE method is an accurate and powerful non-destructive elemental analysis which is applicable in different fields of them is archaeology. PIXE is an appropriate method to study archeological material especially coins, because it has high sensitivity and are quick and non-restrictive. The analysis of coins which using of this method is based on this assumption that available rare elements in coins particularly gold can be considered as a criteria to check the number of mine. The elements such as Arsenic, Antimony, Copper, Zink, and Tin during mining are separated from silver and the amount of their density in the final mining is less than 2%. These elements can’t be used to identify the place and types of stone in mine. Among the elements reporting silver in their analyses, only Gold is effective in identifying feature and origin of silver, because gold is the only element which has fixed amount of density compared to silver. In the process of cupellation, gold is not influenced by oxidation and is remained in silver. Therefore it can help us to identify the mines. If this amount is different, it can be a marker of different geographical region. Furthermore, the amount of element density can be useful in the analysis of politico-economic conditions studying in that period. In this article, as a result of decomposition of element in coins, the amount of gold density was identified. The amount of density of this element in coins shows used mine stone in coin number two of Orod with the amount of 41% gold was minted in Susa and coin number 8 of  Farhad with the amount of 72% gold minted in Ekbatan, was different from other coins and showed different mine. Thus, the analysis of findings about elemental composition of coins reveals that the Parthian government used various mines to supply used metal for minting silver coins. A total of 15 studied coins, 4 coins was belonged to Orod minting at Ekbatan, Susa, Mitrdat kert, and Rey. The amount of silver in these coins is between 87.29 to 93.65 % which shows the high amount of silver in these mints; and also, 11 coins belonged to Farhad which one was minted in Laodicea, 7 in Miterdat kert, and 3 in Ekbatan. The amount of silver in minted coins in Ekbatan was between 86.13 to 90.73% , in Miterdat kert between 56.58 to 86.49 and in a coin belonged to Laodicea 91.66%. The results of this research shows that the amount of silver in coins of Orod compared to coins of Farhad refer to favorable economic conditions in the period of this king. It can be said that the victory of Parthian in Karhe war was the reason of these favorable conditions, because the winning over Romans lead to occupy the Mesopotamia lead to politico-economic stability. On the other hand, high fluctuation in coins of Farhad minting in Miterdat kert, compared to coins of Orod minting in Ekbatan and Laodicea, shows the different politico-economic conditions of western and eastern part of kingdom in the period of Farhad.