مطالعات زمین‌باستان‌شناختی محدودۀ باستانیِ کافرستان یسن، جنوب‌شرقی دیلمان، گیلان

در زمین باستان شناختی، با تشخیص و بررسی محتوای رسوبی و چینه نگاری لایه ها و مواد فرهنگی-باستانی می توان درک کامل و صحیحی از تاریخچۀ تحول های طبیعی-فرهنگی مکان های باستانی به دست آورد. پژوهش حاضر، نتایج مطالعات زمین شناختی اولیه در محدودۀ باستانی کافرستان یسن را ارائه می کند که با هدف شناخت کلی زمین شناسی محلی و زمین ریخت شناسی محدودۀ موردنظر انجام گرفته است. مکان های باستانی محدودۀ باستانی کافرستان یسن عمدتاً برروی تراس های فرسایشی دامنه ای احداث شده اند. در محدوده های استقراری مانند گردکولیسی، به نظر می رسد که سازه های معماری باستانی به عنوان تله های رسوبی برای انباشت رسوبات واریزه ای و آبرفت های دامنه ای عصر هولوسن روی سطح تراس های دامنه ای عمل کرده اند. محدودۀ زرگولسی برخلاف دیگر محدوده های باستانی در محدودۀ یسن، برروی یک برجستگی طبیعی (natural ridge) منفرد متشکل از سنگ های سیلتی و ماسه ای مشرف به رودخانۀ اشکول دره بنا شده است. مطالعۀ نهشته های رسوبی سطحی در نیم رخ های طبیعی و دیوارۀ ترانشه های حفاری نشان می دهد که در اغلب محدوده ها دو بخش رسوبی شامل رسوبات گراولی بسیار درشت درحدّ تخته سنگ و رسوبات گراولی ریزدانه در زمینۀ غنی از رس قابل تفکیک است. آثار معماری باستانی گاهی به صورت هم سطح با رسوبات گراولی درشت دیده می شود و در برخی از نقاط توسط رسوبات آبرفتی ریزدانه پوشیده است. پژوهش حاضر براساس فعالیت های میدانی و به روش توصیفی تحلیلی، به دنبال پاسخ گویی به پرسش هایی هم چون: 1) چگونی ارتباط میان محیط زمین شناسی و زمین ریخت شناسی محدودۀ باستانی کافرستان یسن با ویژگی های فرهنگی محدوده های باستانی؛ و 2) میزان تاثیر ویژگی های محیطی محدودۀ مزبور بر کاربری و مکان گزینی محدوده های باستانی کافرستان است. به نظر می رسد رسوبات درشت تخته سنگی مربوط به یک مرحلۀ رسوب گذاری قدیمی تر باشد که احتمالاً در یک نیم رخ دامنه ای متفاوت با وضعیت کنونی ته نشست یافته است. رسوبات آبرفتی ریزدانه عمدتاً محدود به لایه های سطحی است و احتمالاً نمایانگر رسوبات تاریخی (historical deposits) است که در یک نیم رخ دامنه ای مشابه با وضعیت کنونی ته نشست یافته است. در برخی از نقاط این رسوبات توسط یک سامانۀ آبراهه ای جدیدتر بریده شده است.

The Geoarchaeological Studies of the Archaeological Area of Kafiristan Yasen, Southeast of Deylaman, Guilan

AbstractIn geoarchaeology, a complete and accurate understanding of archaeological siteformation processes can be obtained by identifying and examining the sedimentary deposits and stratigraphy of archeological layers. This study presents the results of preliminary geological studies in Kafiristan Yasen archaeological area to provide a general understanding of local geology and geomorphology of the area.  Kafiristan Yasen archaeological sites are mainly built on hillslope erosional terraces. In settlement sites, such as Gerdekulisi, it seems that ancient architectural structures acted as sediment traps for deposition of debris sediments and recent hillslope alluvial sediments (Holocene) on the hillslope terraces. Unlike other ancient sites in the Yasen area, Zargolesi site is built on a single natural ridge consisting of siltstone and sandstone rocks overlooking the OshkoulDareh River. The study of surface sedimentary deposits in natural soilas well asexcavation trenches shows that two sedimentary units consisting of very coarse gravelly sediments and fine gravelly sediments in a clayrich matrix could be distinguished in most of the areas. Archaeological artifacts can sometimes be found in the context of coarse gravelly sediments and in some places are covered by finegrained alluvial sediments. The gravelly sediments appear to be related to an older sedimentary phase that might have deposited in a different surface morphology to the present situation. The finegrained alluvial sediments are mainly confined to the surface layers and probably represent historical sediments which have been deposited in a hillslope profile similar to the present situation. In some places these sediments have been cut by a later drainage system.Keywords: Geoarchaeology, Geomorphology, Archeological Site, Kafiristan Yasen.IntroductionGeoarchaeology is a rather new interdisciplinary approach that studies the past of human history using geological methods. In geoarchaeology, a complete and accurate understanding of ancient records can be obtained by identifying and examining the sedimentary content and stratigraphy of archeological layers and materials. Geology has been available to archaeologists over the past two decades as a basic tool for reconstructing ancient environments and understanding the longterm climatic and anthropogenic conditions and interactions of prehistoric human with the surrounding environments. These studies are particularly influential in understanding the Pleistocene and Holocene archaeological and geological backgrounds and materials. Geoarchaeological studies in Iran are mainly confined to Paleolithic sites and the use of geological methods such as sedimentology to describe the details of ancient records in caves and rock shelters. Geoarchaeology is an interdisciplinary discipline between geological sciences and archeology that examines the role of geological factors in the rise, continuation, and fall of ancient settlements. In this field, techniques and methods common in earth sciences such as aerial photography and satellite imagery, sampling, microscopic studies, chemical analysis, etc. are used to solve archaeological problems.On the other hand, inarchaeological geology, archaeological data are used to solve geological problems, particularly in relation to dating of Quaternary deposits, ancient seismological studies, and ancient mining. Largescale archaeologists study most of the natural landforms and anthropogenic structures and smallscale archaeologists study the soil, natural sediments, and anthropogenic deposits. Archaeogeology also occasionally covers other interdisciplinary studies such as ceramic petrography, archaeomineralogy, archaeometallurgy, radiometric dating, etc.Identified TracesThis study presents the results of preliminary geological studies in the area of Kafiristan Yasen archaeological site to provide a general understanding of local geology and geomorphology of the area. The Yasen Kafiristan archaeological site comprises a set of settlement and cemetery sites located 35 km southeast of Deylaman. According to previous studies, thechronology of sites in the area varies from the Iron Age to the early Islamic period. Therefore, the present study seeks to map the environmental conditions of the Kafiristan Yasen archaeological sites in terms of geology, geomorphology and climate and to understand the relationship between environmental elements with the cultural and archaeological features of the cultural sites in the study area.Research method of this study is descriptiveanalytical and field study which uses the spatial data related to the research problem to evaluate and investigate the relationship between environmental and cultural characteristics in the ancient sites of Kafiristan Yasen in southeastern Deylaman in Guilan province and to answer the research questions.Gathering information in the field surveys done with the using of observation, survey of landforms and geomorphological and geological processes in an ancient site, justification of features displayed on geological, topographic and climatic maps of the site, as well as utilization of software such as GPS and GIS.ConclusionThe ancient site of the Kafiristan Yasen comprises a series of settlement and cemetery sites located 35 kilometers southeast of Deylaman. The approximate dating of antiquities in this area, according to previous studies, varies from the Iron Age to the early Islamic period. Yasen ancient site enclosures are mainly built on hillslope erosion terraces; the difference between the erosion of the soft layers and the hard layers is probably the main controlling factor for the formation of these hillslope terraces. In settlement sites, such as Gerdekulisi, it seems that ancient architectural structures acted as sediment traps for deposition of debris sediments and recent hillslope alluvial sediments (Holocene) on the hillslope terraces level. Unlike other ancient sites in the Yasen area, Zargolesi site is built on a single natural promontory consisting of silty and sandy rocks overlooking the OshkoulDareh River. The study of surface sedimentary deposits in natural profiles and the wall of drill trenches shows that two sedimentary sections consist of very coarse gravelly sedimentary rocks and fine gravelly sediments in the clayrich can be separated in most of the areas. Archaeological artifacts can sometimes be found alongside coarse gravelly sediments and in some places are covered by finegrained alluvial sediments. The gravelly sediments appear to be related to an older sedimentary phase that may have deposited in a different hillslope profile to the present situation. The finegrained alluvial sediments are mainly confined to the surface layers and probably represent historical sediments which deposited in a hillslope profile similar to the present situation. In some places these sediments have been cut by a later watercourse system.