مطالعۀ پتروگرافی سفال‌های هزارۀ چهارم قبل‌ازمیلاد محوطۀ نارجوئیه iii جیرفت

فرهنگ علی آباد، یکی از مهم ترین فرهنگ های مربوط به هزارۀ چهارم قبل ازمیلاد (مس وسنگ جدید) در جنوب شرق ایران است که پراکندگی سفالینه های آن را می توان در مناطقی همچون استان کرمان، استان سیستان وبلوچستان و غرب کشور پاکستان مشاهده کرد. در بررسی های باستان شناسی مربوط به فرهنگ مذکور، محوطۀ نارجوئیه iii شناسایی گردید که دارای سفال های شاخص این فرهنگ بوده است. در این پژوهش سعی شده با طرح پرسش هایی درخصوص چگونگی نحوۀ فرآوری خمیره، نوع خاک و شاموت مصرف شده، شرایط و حرارت پخت در کوره و هم چنین تاحدودی به منشا ساخت سفال های این منطقه(؟) پاسخ داده شود. در همین راستا به منظور مطالعۀ فنی (اطلاعاتی نظیرِ نوع خاک مورد استفاده و نحوۀ فرآوری آن، منشا و شیوۀ ساخت) این سفال ها از روش پتروگرافی مقاطع نازک در زیر میکروسکوپ پلاریزان استفاده گردید. براساس مطالعۀ کانی شناسی می توان سفال ها را ازنظر نوع پتروفابریک به دو دستۀ سیلتی (ریزبلور) و پورفیری (درشت بلور) تقسیم بندی کرد. تمام سفال ها ازنظر خصوصیات کانی شناسی از ویژگی های یکسانی پیروی می کنند که بیان کنندۀ استفاده از یک نوع خاک یکسان است. دانه های خمیرۀ افزوده شده را می توان به راحتی در اندازه های درشت شناسایی کرد، که این دانه ها به صورت دانه های کوارتز با لبه های تیز و زاویه دار، پلاژیوکلاز، دانه های میکا و خرده سنگ ها هستند. سفال ها ازنظر منشا ساخت دارای منشایی واحد بوده و با مقایسه با رِخنمون زمین شناسی منطقه، احتمالاً بومی و مربوط به همان منطقۀ کرمان هستند. دمای پخت سفال ها را براساس کانی های شناسایی شده کلسیت و مسکویت می توان تاحدودی تخمین زد که برای 5 قطعه باتوجه به حضور کلسیت پایین تر از 850 درجۀ سانتی گراد و در سفال هایی با دانه های مسکویت نارنجی متمایل به زرد تا 950 درجۀ سانتی گراد درنظر گرفته شده است.

the study of petrography of the 4th millennium b.c. pottery of the narjuiyeh in jiroft

abstractthe site of narjuiyeh iii is located on the eastern natural mounds of the narjuiyeh village, from the west overlooking halil river. scattering of the fourth millennium bc, especially typical aliabad type are visible on these mounds. traces of illegal excavation are also available as pits and holes all over the site. aliabad ceramics are pottery dating back to the fourth millennium bc (chalcolithic) in the southeast of the iranian plateau, first excavated and reported by caldwell from aliabad in bardsir of kerman, and then have been found and reported from fourth millennium layers of tell iblis (iblis iv) which eventually became known as aliabad culture (caldwell, 1967).      aliabad culture potteries (chalcolithic age) dates back to the 4th millennium bc in southeast of iran which the distribution of its potteries include the regions of kerman, balouchistan and pakistan. aliabad pottery in the southeast of the iranian plateau is one of the most important and prominent pottery types in the chalcolithic period (eskandari and mollasalehi, 2017), which for more detail understanding about this culture in addition to archaeological studies, requires scientific archaeometric analysis and methods; therefore, the aim of the present study is to investigate, study and further understand the fourth millennium bc pottery of aliabad culture from jiroft’s narjuiyeh iii site and understanding the expansion of this culture by using structural and technical studies of pottery of this period. at the same time, it has been attempted to use the method of mineralogy (petrography) to get information about how to process the paste, clay type and used temper, conditions, heating and temperature of baking in the furnace, as well as the understanding of the origin of pottery of this area. archaeological studies show that aliabad culture in the southeast of the iranian plateau was the dominant culture of the region in the fourth millennium bc. in this study, it has been attempted to obtain mineralogical information regarding pottery (aliabad pottery) using library and thin section petrography studies. the polarized binocular microscope jamesswift made in the united kingdom at the petrographic laboratory of the institute for restoration and conservation was used for microscopic study of the studied pottery.keywords: archaeometry, petrography, aliabad culture, narjuiyeh in jiroft, southeast of iran.introductionfrom the textural point of view, the pottery was divided into two main categories of finegrained and coarsegrained specimens. in finegrained specimens, the components are less than 0.5 mm in size, and the components are finely crystallized in the texture of pottery. a group of pottery has immature silty texture. in the texture of these potteries, there are fragments of different sizes next to each other, and there is some clutter and disarrangement to the size of the minerals in the pottery. in terms of composition, all available pottery has the same composition and their difference are in the percentage of pieces in the pottery texture and their size. in all available ceramics, there are several minerals, including quartz, in the form of monocrystalline (monocrystalline) and polycrystalline, which are more abundant in monocrystalline form. this mineral has angular to semicircular margins indicating that quartz fragments have been added as secondary to the primary source. in some samples, minor amounts of plagioclase, pyroxene and amphibole with mica are observed. mica minerals are mostly muscovite grains that are orangecolored, but sometimes orangeyellow muscovite grains can also be seen in the samples. this reaction is due to the change in the optical properties of the grains at a temperature of approximately 1000 degrees celsius, which can be partially detected the temperature the pottery tolerated on during the heating process. in some samples igneous rock, chert and quartz rock fragments were used as fillers. in some pottery, calcite minerals can also be observed and used to detect its temperature range. therefore, it can be concluded that due to the geology of the region and the presence of calcium carbonate in the sedimentary deposits of the region, the absence of calcite mineralization in some samples indicates that the temperature of the ceramics is higher than 800 °c, and in calciteclay ceramics, the baking temperature of the clay is less than 800 °c (reedy 2008; riederer 2004). the two n9 and n7 specimens differ in composition from the other specimens. in these two samples calcite minerals are associated with the clay texture, whereas in the other samples this is not the case.conclusionbased on the petrographic study of the pottery, it can be deduced that the source of the pottery studied was identical and their source material was from the same region in kerman. however, the origin of manufacture and extracting of soil mines cannot be determined definitely, because the geology of the kerman region is very large and vast especially the studied areas are in volcanic formations, which, the mineralogical composition and sequence of some of them are granite, granodiorite to quartz. metamorphic, plagioclases, clinopyroxenes, and mica minerals and igneous and metamorphic rocks are within the geological family of the area, which exactly similar compounds can be found with the minerals in the pottery. there are also three different groups for these pottery: 1) pottery with homogeneous texture. in this type of pottery, fragments and minerals are seen floating and scattering in the texture. 2) pottery in the texture in addition to clay and fine minerals, phyllosilicate minerals (mica) exist in combination with the texture. 3) in these ceramics the combination of the texture of mineral carbonate calcium (calcite) together with the clay texture is visible, a situation not seen in the other samples. this indicates that the pottery used has different manufacturing techniques, therefore, several pottery makers have been involved in preparation and procurement of early paste and clay of the pottery. pottery samples n5, n6, n7, n8 and n9 contain calcite minerals. it can be suggesting that the baking temperature of these pottery was less than 800 degrees celsius. in the samples containing muscovite minerals, some of the grains show changes from orange to yellow, indicating that these ceramics have been sustain a temperature of approximately 9501000 °c. based on the results and even the bufforange color of the ceramics, it should be noted that the analyzed pottery were baked in an oxidation condition and in a closed furnace. the type of baking and precision used in baking the pottery in high quality, especially the 4th millennium bc pottery, is very high, indicating that the technique used in baking pottery was also very professional. some ceramics, such as (n1, n8, n9) have porphyry texture and in their texture quartz mineral, chert stone and igneous rock have been used as filler and temper. in most cases, the edges of quartz minerals are edged and sharp, which, indicates the use of primary soil and its paste processing and resultant of grinding of core and ore extractive mining because all fragments and sherds have sharp and angular angles as well. it should also be noted that there is no evidence of the use of organic materials as temper in pottery making.