CONTRIBUTION TO ACTIVE CONSERVATION: CHARACTERIZATION OF NEOLITHIC PERIOD MUD BRICKS REMAINS OF THE ARCHAEOLOGICAL SITE OF ÇATALHÖYÜK-TURKEY

Abstract

In the 2014 excavation season, 6 mud brick samples were taken from different Neolithic layers of the Eastern mound of Çatalhöyük (C14 cal. 7100-5950 BC). For characterization of mud bricks, we carried out the following archaeometric techniques and analysis; hydrometer, atterberg limits, loss on ignition, deal with acid and sieve analysis, petrographic analysis (thin/thick sections, Stereo and Polarizing Microscope observations), X-Ray Diffraction (XRD) and Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy (SEM-EDX). This methodology were performed for the first time in this study on mud bricks at Çatalhöyük.
According to results of this study, the chemical content of materials used in the mud bricks, the type/ratio of the binder, the particle size distribution, the effect of water content on volume change and soil consistency, as well as the type/ratio of the additives and filling materials could be determined. The results shed light as a reference point for the further mudbrick studies of the prehistoric period in Anatolia. As an interdisciplinary study, one of the goals of this research was to determine the chemical contents and physical properties of earthen building materials of Çatalhöyük to be able to make the same adobe mixtures for conservation activities. By using these compositions during the conservation treatments, original composition and characteristics of restoration mortars will not have been changed and physical stresses on original materials will be prevented.
Carried out in conjunction with the Konya Basin Paleoenvironments Project (KOPAL), the source of raw materials, binder and tempering agent used in each building from different layers were determined. The results of this study revealing clearly that the raw materials used for making mud bricks were derived from local resources nearby settlement. At the same time, the binders and additives were added to the raw materials in 4 different layers (VIA-IX layers) not only have been in each layer, but also in different buildings of the same layer have been changed (samples 1-2: buidings 80-76 and samples 3-4: buildings 7-11) in order to produce more robust and durable mud bricks.
The results proved that in the early layers of Çatalhöyük (layer IX/6800-6700 BC) only clay (muscovite) and organic additives (straw) were used for manufacture of mud bricks. But in VIII layer (6700-6600 BC) they were used two type of clay (kaolinit+muscovite). In VIl Layer (6600-6500 BC) gypsum were added to mud bricks for the first time as binder. In VIA Layer (6500-6400 BC) firstly gypsum and slacked lime were used together and then only the slacked lime were used.