Lab Methods

Flake Stone tools

• chipped or knapped

• Sharp edges required for cutting, scraping and piercing

• Material requirements: hard, fine grained, homogenous

Ground Stone tools

• pecked, ground, polished

• Edges required for grinding, smashing, or splitting

• Choice of material: dense, crystalline, resilient, homogenous

XRF (X-Ray Fluorescence)

• Measures the elemental composition of a material and determines which elements are present

NAA (Neutron Activation Analysis)

• Measures trace elements with very high precision

LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry)

• Measures trace-element concentrations at very low levels

what makes a stone knappable?

• Homogeneity- even internal structure

• Elasticity- ability to store and release energy when force is applied

• Brittleness- breaks rather than deforms

• Isotropy- fractures propagate evenly in all directions

Conchoidal fracture

• glass like or smooth, curved, shell-like fracture surfaces.

Sub-conchoidal fracture

• irregular, smooth on breaks but uneven; step or hinge fractures common.

Granular/crystalline fracture

• breaks along grains or crystals; dull, angular fragments.

Anatomy of a flake

Cortex

• outer layer of a rock

• can be used as an indicator of the tools reduction stage

links between flake attributes and behaviour?

• Economy: control and intent in flake production (efficiency, raw material management)

• Process: Stage and structure of reduction (where in the sequence the flake comes from)

• Strategy: Reduction strategy and technological tradition (how flakes were removed, not just when)

Ad hoc methods

• Opportunistic, unplanned, low predictability in shape and size outcomes, and limited platform management

• Bipolar methods

• used to make flakes

Planned methods

• pre-conceived core reduction methods

• ex. Levallois

• used to make blades

Biface

• a stone artifact that has been intentionally flaked on both faces to shape, thin, and control its overall form.

Halfing module (base)

• a set of dimensions and forms that make a biface fit and function within a haft

Approaches to debitage analysis

• Attribute-based

• type-based

• stage-based

• mass analysis

Attribute Based

• measurable variables used to characterize flakes to identify the reduction processes and technological activities

Type Based

• classificatory scheme that organizes variability in debitage.

stage-based

• Classifies individual pieces of debitage on the amount of cortex on their dorsal surface

mass analysis

• records mass by size gradient at the assemblage level

• a pattern-recognition approach that correlates size distributions with particular reduction modes

retouch

• removals made by percussion or pressure, with the intention of making, finishing or sharpening tools

Tool Attribute Analysis

• Delineation: shape of the retouched edge

• Extent: depth of retouch

• Angle: formed by retouched edge

• Localization: where on the blank

• Morphology: of the retouched

• Position: which side of the tool

• Distribution: characteristics along edge

Use wear analysis

• The study of microscopic modifications on a tool’s working edge or surface that result from use

• What material was worked (e.g., hide, meat, wood, bone, plant fibres)

• What motion was used (e.g., cutting, scraping, drilling, sawing)

Use wear analysis allows us to

• Reconstruct specific tasks

• Evaluate tool design and hafting

• Assess tool use-life and maintenance

• Reconstruct site activities and economic behaviour

What is a striking platform?

The specific surface on a stone core where a blow is struck to detach a flake.

What is a core?

A lithic artifact used as a base for which other tools and flakes are made

What is a flake?

A piece of stone removed from a larger piece (the core) via percussion or pressure.

what is the bulb of percussion

The small bump on a stone flake where the rock was hit with another stone to break it.

What does unifacial mean in lithics?

Tools that are only worked on one side.

What does bifacial mean in lithics

Tools that are worked on both sides.

What is the importance of non-local stone sources in lithics?

They indicate travel or trade networks among early humans.

Types of Chipped artifacts

• objective pieces- hit, cracked, flakes, modified

• detached pieces - removed from objective pieces during modification

Percussion flaking

• Removal of flake/chip through striking the objective piece with a hammer or percussor

Pressure flaking

Removal of flake/chip by applying pressure to the objective piece w/o striking

• more accuracy

ideal flake types

• conchoidal

• compression

• bending

Igneous

• obsidian

• quartz

Metamorphic

• quartzite

cortial

• unimodified cortical surface of the objective piece

Flat

• flat surfaces impacted to remove detached piece

complex

• rounded or has multiple flake scars

abraded

• smoothed by abrasion or rubbing