stone tool

Microwear analysis-determining the function of chipped stone tools

One of my technical specialties is high-powered microwear analysis, a method by which the function of chipped stone tools can be determined. Pioneered by Semenov (1964) and refined by Keeley (1980), the high-powered magnification approach has repeatedly demonstrated that variability in polish formation on utilized surfaces is related to tool use on different materials (e.g. soft tissue, hide, bone, wood, etc.). Striations, or the grooves and scratches of varying orientation and dimensions which often result from abrasive forces imparted during tool use are important indicators of intentional and unintentional motion, such as friction between a stone tool and its haft and/or the contact material being worked.  Taken together, micropolish and striations provide information on contact material, tool motion, and hafting.  In this manner, the identification of distinct surface and edge alteration of tools can be related to prehistoric patterns of activity and raw material use and utilized in the reconstruction of the organization of cultural behaviors.

Today I continue to work on material from three sites. Two sites were recently excavated by a Cultural Resource Management firm as contract excavations. These sites, which date from the Late Archaic and Woodland periods, were investigated to fufill compliance laws prior to disturbance. As part of the data recovery plans, the principle investigators have included a budget for analysis, a part of which is microwear analysis to determine the function of chipped stone tools recovered on site. A range of formal and informal tools were recovered, and so far, results indicate a wide variety of tasks  including butchery, hide,  and bone and wood working occurred on site.

The third site I am working on is the famous Lindenmeier Folsom site in Colorado. These materials were excavated and/or collected in 1934-40 during work at the site by Frank Roberts. Microwear analysis of a sample of endscrapers recovered from the site reveal that many of them were employed in the later stages of hide working. Edge wear in the form of eroded resharpening scars and heavily rounded edges along with a well formed dull-pitted polish characteristic of dry hide was present (see photomicrograph).  During late stage hide working, the edges of the tools are allowed to dull, so that accidental tearing of the hide during stretching and softening is lessened. Some endscrapers were discarded with sharp, fresh edges indicating use during earlier stages of hide working where cleaning and thinning is the object. These discard patterns illuminate the activities that took place on site, and when coupled with an assemblage of worn out, broken and discarded projectile points suggest active hunting and transport of fresh hides for processing at the site was common.  Here is a prime example of the value of why collections should be curated, as when they continue to be available for analysis, we can continue to learn from them.

Heavily worn and rounded distal edge of unifacial endscraper used on dry hide.


A Day in Japanese Archaeological Laboratory

I’m an archaeologist living and working in Japan. I’m a researcher of Meiji University Archaeological Investigation Unit. This unit is organized for preventive excavation within university campus.

In Japan, all archaeological sites are conserved under the national law. Local governments develop a registration map of archaeological sites and check all land development. In order to keep to the law, all developer and constructor – not only commercial sector but also public/administrative sector- must make an effort to conserve archaeological sites within their development/ construction area. If they cannot change their plans, they must do excavation. More than 95% of excavations carried out in Japan are this type – preventive excavation…documentation before destruction of sites for those 40yrs.

As you know Japan has large population- about 120 million- in small land. Most parts of our landscape are hilly or mountainous, so our living spaces are definitely limited and overlaid on ancestor’s lived space. This is the cause of so many excavations – more than 8,000 in average/year and the peak was about 12,000 in 1996…- have done every year.

In 2004, our project was started. It was for the construction of new buildings of the university affiliated junior-high and high school. At first we did survey and sounding in total 40,000 sq-meters area, then begun excavation in 18,000 sq-meters area. The excavation continued for 2 years and 5 months – more than 800 days. We unveiled Modern Age (including Imperial Japanese Army and occupation Allied Force sites during WWII ), Jomon Age (mostly Middle Jomon, 6-4.5ka) and the Upper Palaeolithic Age (32-16ka). Now I’m constructing web-site for our excavation (https://sites.google.com/site/japarchresources/ :it’s not completed) .

aerial view of our excavation area in 2005

aerial view of our excavation area in 2005

excavation of the Upper Palaeolithic living floor

excavation of the Upper Palaeolithic living floor

excavation of a shelter for air fighter of Imperial Japanese Army during WWII

excavation of a shelter for air fighter of Imperial Japanese Army during WWII

documentation of the Late Pleistocene staratigraphy

documentation of the Late Pleistocene staratigraphy

Our excavation was finished in Dec,2007. However it means finishing just the first step only in the field… we have more than 500 containers filled with artefacts such as: 5,000 potsherd and 40,000 pebbles of Jomon, 25,000 lithics and 90,000 pebbles of the Upper Palaeolithic, more than 200GB of digital images and measurement datum by total station system… and so on.

Since 2008, we’re engaging with the post-excavation procedure and it will continue until 2015. We have published the 1st volume of our excavation report this May and will publish other 5 volumes over 5 years.

This is our background. And here I show our habitual day in post-excavation laboratory of our investigation unit. Now we’re tackling with Jomon and the Upper Palaeolithic materials.

The first section is for Upper Palaeolithic pebble refitting work. We uncovered more than 300 stone heaps composed with 90,000 pebbles. Most of pebbles are burnt and fragments. These stone heaps are assumed for cooking, as in the Pacific ethnography.

This work has started in 2010 and will continue for the next 2 years. There are many pebbles in containers waiting for their turn…

Upper Palaeolithic pebble refitting

Upper Palaeolithic pebble refitting

Upper Palaeolithic pebble refitting(2)

Upper Palaeolithic pebble refitting(2)

These workers are from the commercial company engaging in preventive archaeology.

more pebbles are waiting their turn...

more pebbles are waiting their turn...

all containers are fulfilled with material

all containers are fulfilled with material

The second section is for Upper Palaeolithic stone tools (lithic technology) refitting. This work has started in 2007 and will finished this year.

Basically we start from distinguishing chipped stone tools and debitages into petrological classification and making sub-divisions acording to their colour, texture, micro-structure and other characteristics. This is very empiric but very efficient method. Up to now we have documented more than 6,000 cases of refitting in 25,000 specimens of lithic material. In some cases, we can reconstruct original shape of nodule and decode total sequence of knapping technology. Of course, to determine source of raw material, we apply archaeo-scientific analysis.

Lithic refitting work(1)

Lithic refitting work(1)

Lithic refitting work(2)

Lithic refitting work(2)

arrange debitages with raw material, texture and other character

arrange debitages with raw material, texture and other character

documenting which pieces are and how they are refitting in sequence

documenting which pieces are and how they are refitting in sequence

The third section is computer application for managing the database, drawing maps and artefacts, geo-spatial analysing and editing publications. We use Microsoft(R) Access(2007)(R) for database managing; Inteli CAD(6.0J) for arranging and original drawings measurement survey datum, 3-dimensional distribution maps of artefacts; Adobe(R) Illustrator(CS5)(R) for drawing artefacts and finising maps and other figures for publication; Arc GIS<sup>(R)</sup>10 for geo-spatial analysing; Adobe(R) InDesign(CS4)(R) for editing publications. Some part of these computer works are put out to commercial companies, those which have specific technique and systems.

computers in our laboratory

computers in our laboratory

a drawing of stone tool (Upper Palaeolithic backed blade)

a drawing of stone tool (Upper Palaeolithic backed blade)

drawing distribution map of Upper Palaeolithic lithic concentration

drawing distribution map of Upper Palaeolithic lithic concentration

database for chipped stone tools of Upper Palaeolithic

database for chipped stone tools of Upper Palaeolithic

geo-spatial analysing of Jomon inter-site components

geo-spatial analysing of Jomon inter-site components

Post-excavation laboratory working continues…however I hope to go back to the field…yep I should!!!!

A Student has Arrived!

My first student volunteer just  walked in at 9:55 am. Davis is in my Summer II Introductory class Anthropology 101 Primates, People and Prehistory.  Davis is now equipped with a rather expensive, fragile and hard to replace item of lab equipment and has commenced Day of Archaeology work.  Using this item he is carefully removing the sandy soil that adheres to our artifacts.  Using a basin filled with two gallons of warm water he cleans stone flakes discarded during the manufacture of stone tools, 2500 year old and 2000 year old Native American pottery sherds, some brick fragments, petrified wood, and a small broken arrow point made of crystal quartz.

That rather expensive, fragile and hard to replace item of lab equipment is a tooth brush from the dollar store!

 

What are we doing in the lab?

Every week I run an open lab for anyone who wants to walk in and help wash, sort, bag and catalog the artifacts we have recovered.  This summer our lab day is weds.  Today the drying racks in the lab are full so it is time to sort the artifacts into categories– brick, historic period ceramic fragments (known to us as sherds) glass shards, stone tool making debris, stone tools, nails-wrought, cut and wire.

Each type above gets a separate ziplock bag and a catalog number– a unique number that signifies exactly where in the site this batch of artifacts was recovered.

This is a first step towards artifacts analysis.

Several blocks away from the lab is an old cotton warehouse turned into a storage facility.  There we have rented a space to store the massive collection we have amassed in 16 years of research. The Kolb artifact assemblage is stored in 600 plus cardboard bankers boxes.  Over time our lab staff and Carl have sorted these by types–stone tools, prehistoric ceramics, historic ceramics, animal bones, botanical specimens have all been culled from the collection and are stored together.