Will we ever be able to reconstruct prehistoric pottery production processes –the role of experiments

WILL WE EVER BE ABLE TO RECONSTRUCT PREHISTORIC POTTERY PRODUCTION PROCESSES: THE ROLE OF EXPERIMENTS Andreja Kudelić Institute of archaeology Center for experimental archaeology CROATIA - Zagreb 10th Experimental Archaeology Conference EAC10 20-22 April 2017. Leiden (NL) Kudelić, A. 2017. Will we ever be able to reconstruct prehistoric pottery production processes – the role of experiments. Experimental archaeology conference, book of abstracts / Paardekooper, Roeland (ur.). - Leiden, 2017., 49-49. ABSTRACT Within the research program, Bronze Age pottery from several archaeological sites in NW Croatia is being systematically studied from a technological and archaeometrical point of view, and the results of these studies enable us to discuss about their significance in the context of a society or culture. However, these analytical methods are not always sufficient for a complete interpretation of the pottery production process. For that reason a research program that includes implementation of systematic experiments related to the different segments of the chain of operations in the process of pottery production is carried out since 2012. The experiments were designed to answer two basic questions: (1) which clay paste recipes (especially organic matter tempered clay paste ) correspond to a paste that was used for pottery making in the Bronze Age and (2) is the destruction pattern of the hypothetically reconstructed firing structure (horizontal pottery kiln) comparable with the archaeological feature excavated at the Bronze Age site Kurilovec in NW Croatia. Pottery technology is a complex social phenomenon and it reflects a complex social behaviours, so possibilities of its reconstruction can be very limited. However, preliminary results of this research show that experiments have a very important role in the reconstruction of temper material preparation process, in the reconstruction of firing strategy and in the interpretation of the archaeological record. MATERIALS AND METHODS • Late Bronze Age pottery from two micro-regions in North Croatia • Results of the macroscopic analysis • Results of ceramic archaeometry analysis • Systematic archaeological experiments Procurement and preparation of raw materials Selection of the clay paste Building vessel Selection of building techniques FORMING EXPERIMENTS 1. clay paste recipe Surface treatment and decoration 2. preparation of temper material Drying Selection of surface treatment method Selection of decorating techniques 3. firing condition and strategy Vs. clay paste recipe 4. firing structure: re-constructed horizontal pottery kiln Firing Selection of firing method Selection of firing atmosphere OPERATIONAL SEQUENCE OF POTTERY PRODUCTION 1. CLAY PASTE composition Procurement of potential raw materials Archaeometry of clay and ceramics Temper material identified Questions and objectives • to test, identify and quantify the 1.1. Grog (recyclred and crushed ceramic) amount of temper • 1.2. Organic material temper (Dry straw, Hay, to determine temper preparation methods Chaff, Ruminants dung) • • Local clay was used for pottery Technological characteristics of temper: making in the Bronze Age. • plasticity of the clay The similar clay was used for the experiments. improve the workability and • insure relatively high thermal stress resistance • to determine the type and amount of organic material temper • to determine recipe corresponds to one that was used for pottery making in the Bronze Age 1.2. Organic temper material - Ruminants dung Experimental tiles The Bronze Age pottery Fresh fracture of experimental tiles and Bronze Age ceramics 3. FIRING METHODS 1% 2% Maximum temperature 700-800°C 5% 7% 20000 18000 counts 14000 NO – incomplete oxidation 36% 7% 16000 R – reduction 3% 12000 KO – short-oxidation 10000 8000 NR – smudging effect 6000 4000 O – oxidation 39% 2000 VA – multiple atmosphere 0 5 15 25 35 45 55 . NO Difractograms of ceramic material from Turopolje and Podravina region in NW Croatia (Kudelić et al. 2018) R-KO NO/NR R-KO/NR R O VA S Diagram presents firing atmosphere according colors recorded on ceramic fresh fracture (Kudelić 2015) Open firing - results 900 800 700 600 500 400 300 200 100 Thermal profiles 0 0:00 0:10 0:20 0:25 F1 Bronze age pottery 0:30 F2 F7 0:37 0:40 0:45 F9 Experimental tiles • Approximate firing duration is between 35 and 45 min. • After 10 – 20 min. temperature reached 700 °C • Temperatures can reach 900°C and maximum temperatures can be regulated by the quantity and quality of fuel. • The temperature can vary by over 200 °C depending on the position of the thermometer • A large percentage of damaged vessels (lack of experience); Pre-heating is necessarily • Atmosphere: incomplete oxidation and reduction with short oxidation Pit firing – reducing atmosphere 700 600 500 400 300 200 100 0 0:00 0:05 0:10 0:15 0:20 0:25 0:35 0:45 0:55 1:05 1:25 1:50 2:00 2:15 2:35 3:00 4:20 5:00 5:20 Thermal profiles F8 F5 4. FIRING STRUCTURE - archaeological record Hypothesis: horizontal pottery kiln 1% 2% 5% 7% 36% 7% 3% 39%  NO R-KO NO/NR R-KO/NR R O VA variations of above ground structure (width and position of the combustion chamber, the position S of the chimney and blowhole ) Diagram presents firing atmosphere according colors recorded on ceramic fresh fracture (Kudelić 2015)  time spent on the construction of the kiln  the amount of material needed for building the kiln ashy soil, coal and daub burnt soil and daub Kurilovec-Belinščica site – feature 14  firing conditions (temperature and heating rate)  the amount of fuel  kiln efficiency Heating rate °C/min. 45 745 35 200 5 One spaced oxidizing 40 730 35 200 5 Two spaced oxidizing 470 730 450 50 20 Two spaced oxidizing 450 730 420 50 20 Pit firing One spaced reducing 180 500 °C F2 F3 Bonfire 400 Kiln1 Thermal profiles remarks Aproximate variation in temperature (°C) One spaced oxidizing 600 Duration to max. temperature (min) Firing method Bonfire Max. temperature Structure F1 Firing duration (min.) 700 800 Date Soaking time (min) Cooling mode/atmosphere Firing Firing conditions (temperature and heating rate) 21,28 2012_may 20,85 2012_june 1,62 2012_june 300 F4 Kiln2 200 F5 110 interupted 100 F6 F7 Kiln3 Two spaced reducing 280 0 1:00oxidizing 1:30 2:00 Bonfire0:00One0:30 spaced Kiln1 35 150 200 180 180 680 270 80 2:30 403:00 730 3:30 4:00 37 4:30 240 260 10 5:00 200 5:30 6:00 5 370 450 530 510 600 650 F8 Pit firing16 One170 spaced Kiln2 280reducing 260 270 370210 360 640350 400 440 200 450 540 25570 F9 Kiln3 30 430 430 425 Bonfire One320 spaced oxidizing 470 680 17 550 350 250 35 520 850640 20 1,73 2012_october interupted 2013_july 2,51 2013_july 6:30 7:45 8:00 19,72 660 2014_october 680 730 600 620 2016_june 730 600 300 7:00 7:30 300 50 2016_october 250 windy Basic characterisation of the experimental firings (table is created according to: Thér 2004; Thér, Gregor 2011., modified by A. Kudelic) Process of creating archaeological record Ruins of the second kiln structure (spring 2014) After third kiln structure (autum 2015) The pit after the second kiln structure (summer 2014) Summer 2016 After third kiln structure (autum 2014) Spring 2017 How to evaluate the experiment? Identify Value! • repetition • interdisciplinary approach • authentic skills • ... Raw material Clay paste Kiln firing One-spaced open firings Building and decorating techniques A B C Diagram presents value assessment of gathered data according operational sequence and based on conducted set of experiments; (A) pre-experiments; (B) first set of experiments; (C) second set of experiments References Acknowledgments Gosselain O. P., Livingstone Smith 1995. The ceramics and society project: An Many thanks to my colleagues, friends and ethnographic and experimental approach to technological choices. In Lindahl, A., and members of the Center for Experimental Stilborg, O. (eds.), The Aim of Laboratory Analyses of Ceramics in Archaeology, Kungl. Archaeology in Zagreb (Silvio Stanković, Filomena Vitterhets Historie och Antikvitets Akademien Konferenser 34, Stockholm, 147-160. Sirovica, Tena Karavidović, Dinko Tresić Pavičić, Kudelić, A. 2012, Experimental testing of prehistoric archeological feature and the Anita i Pavle Dugonjić, Nera Šegvić ...) dr. sc. Andreja Kudelić Institute of archaeology Ljudevita Gaja 32, 10000 Zagreb andreja.kudelic@iarh.hr results of firing ceramic on an open fire, Annales Instituti archaeologici VIII (2012), 145- 148. Kudelić, A. 2013, Testing the technology of pottery production and reconstruction of horizontal pottery kiln, Annales Instituti Archaeologici IX/2013. Kudelić, A. 2015, Technological and social aspects of the Virovitica group pottery finds Center for experimental archaeology Travanjska 18, 10000 Zagreb cexa.zg@gmail.com www.cexa-zg.org in northwest Croatia and their archaeological context (unpublished PhD thesis, University of Zagreb), Zagreb, 2015. Kudelić, A. 2016, Experiment in archeology - preparation and composition of clay paste, Annales Instituti Archaeologici, XII, Zagreb 2016. Kudelić, A., Mileusnić, M., Grzunov A. et al. 2018, Archaeometry and comparative analysis of the Bronze Age pottery from Turopolje and Podravina region, Opuscula Archaeologica Vol. 39/40. Ther, R. 2004, Experimental Pottery Firing in Closed Firing Devices from the Neolithic – Hallstatt Period in Central Europe, EuroREA 1/2004, 35-82. Ther, R. Gregor, M. 2011. Experimental reconstruction of the pottery firing process of Late Bronze Age pottery from North-eastern Bohemia, in: Archaeological Ceramics: A Review of Current Research (ed. S. Scarcella), Archaeopress, Oxford, 128-142 CROATIA