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Usewear Experiments Using Tools from Different Rock Types, Tarragona, Spain

Date: 
Monday, 12 May, 2014 to Wednesday, 14 May, 2014
Responsible: 
Sabine Martin
Number of Participants / Visitors / Audience: 
3

My PhD project focuses on usewear analysis on vein-quartz based on tools found at the site of Gran Dolina in Atapuerca and the site of Payre in France. An experimental protocol was established in an effort to study this mineral.

In Tarragona we tested this protocol on 3 different rock types: quartzite, flint and quartz.

This preliminary experiment established a basic reference collection of the 3 rock types for experimental laboratory in the department of archaeology at the University of Exeter.

The experiment covered 2 days:

Preparation of the 3 different rock types (12th and 13th morning of May)

Use of the flakes (13th afternoon)

I/ Preparation:

a) Knapping:
The quartzite and the quartz were sourced from the Sierra of Atapuerca in Spain. A second batch of quartz was sourced from the Ardèche region in France. Finally, the flint was collected from of Seaton in the UK, were the cobbles erodes out onto the beach.
All the raw materials were knapped by Theresa Kamper.
The knapping sessions took place at the University of Exeter for the flint, at the open archaeological park in Atapuerca for the quartzite and the quartz was knapped at the Institut de Paleontologia Humana Ecologia y Social (IPHES) laboratory in Tarragona.

b) Cleaning the flakes:
The unused flakes need to be cleaned before casts of the edges can be made. The cutting-edges are cast at “Time 0” in order to observe the changes to the edge during its use.

All the flakes were cleaned using this steps:

-15min bath of a 20% Nitric acid solution
-Acetone dip just before casting the cutting-edge

The cast is made with Provo Novil Light Regular, a type of dental tack.
c) Contact materials:
We selected oak (Quercus ilex) and giant cane (Arundo donax) as the materials on which to use the flakes.

The Quercus material was necessary for my PhD and the Arundo donax, being native to Mediterranean region, was a relevant reference plant for the area.

Both materials are hard and therefore will cause noticeable usewear striation on the cutting-edge.

II/ Tool use

a) Sequential experiment:
The protocol previously used on quartz is based on a sequential experiment.

During the sequential study we needed to avoid having too many variables in the experiment.

Hence, each flake was used in a single direction in a one contact material, using only one motion; i.e. unidirectional, bidirectional or scraping.

This procedure allows for maximum control over the motion being used during this experiment and subsequent experiment.
The aim of the sequential experiment is to observe the modifications to the cutting-edge after each round of use. In this study, the cutting-edge is cast at Time 0 followed by the different times of use according to the experiment, which are labelled T1, T2,…etc.

During the Tarragona experiment we chose to use each flake for a duration of 30 minutes, meaning our T1 = 30 minutes.
After microscopic observation the flakes can be used again then labelled with as T2 before undergoing further microscopic observation. Each flake was exchanged between the three participants every 10 minutes.

This exchange enabled us to keep a constant (the direction of the movement) whilst adding an interesting variable (the different strengths).

b) Movements and intents table
(See attached PDF)

Images

Theresa Kamper knapping quartz
Quartz
Scraping Quercus with chert
Scraping Quercus with quartz
Scraping Quercus with quartzite
quartz, chert and quartzite used on Arundo...