Fractures in Knapping

"For more than 40 years, Are Tsirk has developed interdisciplinary research on the physical phenomena in knapping, combining his experience in knapping with his longstanding interest in fracture. The work is enhanced by his curiosity and minute observational ability of a natural scientist. It is the most complete monograph on the subject. It will be of interest to all amateurs in knapping and useful, if not indispensible, to fractographers as well as all archaeologists in the study of lithics." -Jacques Pelegrin, Lab. "Prehistoire et Technologie" CNRS, Paris "The book - is a delight to read. It contains information of interest and importance to the knapper, fractographer and anyone interested in flint knapping or finding out about knapping. It contains so much material in one place that it becomes an invaluable resource. It is easy to read and many of the sections are self-contained - The pictures are marvelous and very descriptive. If you have an interest in history, art, anthropology, fractography or knapping in any aspect, you will enjoy and appreciate this book." -John J. Mecholsky Jr., Materials and Engineering Department, University of Florida, Gainesville "Tsirk understands lithic fracture mechanics better than anyone. - This his latest work will stand as his testament of a lifetime of critically important research in archeology." -Errett Callahan, Consultant in Reconstructive Archeology, Lynchburg, VA

• PART I: ELEMENTS OF KNAPPING 1.Knapping Past and Present Introduction Traditional Crafts and Industrial Society Prehistoric Knapping Recent and Remnant Knapping Traditions Some Specialized Knapping Traditions Gunflints Threshing Sledges Ceramic Industry Modern Knapping and Recent Explosion Of Interest Knapping Studies Archaeological Record Ethnography Knapping Experiments Living Archaeology Mechanics, Fracture Mechanics and Fractography Contemporary Crafts 2.Knapping Tools and Techniques Antler and Wood Billets Hammerstones Punches Pressure Flakers Holding and Fabricating Devices Anvils and Supports Hides Grinding and Abrading Stones Nontraditional Tools and Acessories Use-Wear Indicators Direct Percussion Anvil Technique and Anvil Percussion Bipolar Percussion Indirect Percussion Pressure Flaking Pecking, Grinding, Polishing Edge and Platform Preparation Some Rules of Thumb Knappers' Wisdom, Folklore and Dilemmas Softer Percussors and Slower Blows Follow-Through with Forces Ridge Abrasion Wetting and Soaking Learning to Knap 3.Raw Materials Material Selection and Use Obsidian Flint and Chert Other Materials Physical and Mechanical Properties Microstructure and Physical Properties Homogeneity and Isotropy Elasticity, Ductility, Brittleness Elastic Constants Constants for Thermal Effects Strength and Fracture Toughness Mirror Constants Workability Alteration of Properties And Behavior Hydration and Vesiculation of Obsidian Cortex and Patina on Flint and Chert Thermal Cracking Thermal Alteration and Heat Treatment Environmental Effects Procurement Nontraditional Uses of Obsidian, Flint and Chert PART II - FRACTURE MARKINGS: THE TOOLS OF FRACTOGRAPHY 4.An Overview 5. Hackles and Hackle Scars Twist Hackles and Single Tails Multiple Tails Parabolic Double Tails Hackle Scars Hackle Scar and Hackle Flake Bulbar Scar and Proximal Scar Ripple Scars Ridge Scars More on Hackle Scar Formation 6.Ripples Ripples Wallner Lines Normal Wallner Lines Anomalous Wallner Lines Stress Changes Causing Ripples Static Effects Specimen Vibration Stress Pulses Experimental Ripples Ultrasonic Modulation Sonic Modulation Exploding Wire Experiments Terminology and Interpretations by Others 7. Mirror, Mist, Hackle, Branching Mirror Mist and Velocity Hackle Branching, Incipient Branching and Lateral Wedges Velocity and Energy Considerations Mirror Constants and Stresses Markings Related to Mist and Hackle Wallner Mist-Hackle Configuration Mist Suppression Configurations Mist Lines 8.Miscellaneous Markings Material Interface Markings Material Interface Ridges and Ripples Material Interface Hackle Material Transition Ridge Split Marks Dividing Lines Ruffles Liquid-Induced Fracture Markings (Lifms) Effects of Moisture and Liquids Conditions for Manifestation of LIFMs Occurrence of LIFMs Significance of LIFMs Basic Kinds of LIFMs A Catalogue of LIFMs and Patterns Observation of LIFMs Variability with Liquids Variability with Lithic Materials LIFMs with Sonic Modulation LIFMs Observed with Condensation Some Surface Patterns PART III - FRACTURES IN KNAPPING 9.Introduction Elements of a Mechanical System And Knapping Stresses, Stress Waves and Vibrations Some Fundamentals in Fracture Mechanics Catastrophic and Subcritical Crack Growth Research on Fractures in Knapping Other Research 10.Flake Initiations, Proximal and Surface Features Flake Initiations Some Definitions Hertzian Cone Fractures Contact Initiations Non-Contact Initiations Initiations with Multiple Blows Effects of Cortex and "Layering" Environmental Effects Percussor Softness and Speed Proximal Flake Features Platform Characteristics Dorsal Ridges and Curvatures Interior Platform Edge Wing Flakes Bulbs Popouts and Stepouts Flake Surface Features Fracture Directions Ripple Configurations and Fracture Fronts Ripple Concavity Ripples Related to Flake and Core Geometry Ripples at Inhomogeneities Why Ridges Guide Flakes Fracture Velocities Mist and Related Markings Hackle Scars Ruffles Split Marks Tails and Incipient Tails 11.Crack Paths and Flake Profile Features Criteria for Crack Paths Crack Paths and Core Geometry Crack Paths and Forces Applied Popouts and Related Fractures Compression Lips, Curls and Compression Wedges Step-In and Step-Out Fractures Incipient Breaks Popout Fractures Ripple Profiles and Kinks Wavy Crack Paths Flake Terminations "Jacked" Flakes 12.Forces in Knapping Non-Contact Flake Initiations Edge Angle and Core Geometry Location and Direction of Force Application Platform Characteristics Flaw Distributions Flaker Properties Contact Initiations Location of Force Application Direction of Force Application Edge Angle and Core Geometry Platform Characteristics Flaw Distributions Flaker Properties Contact and Non-Contact Flake Initiations: Comparisons Subsequent Detachment Direct Percussion Percussor Characteristics Velocity of Blows Indirect Percussion Punch Characteristics Striker Characteristics Core Mobility Percussion Flaking Pressure Flaking Supports Distal Dorsal Bipolar Percussion 13. Breakage of Blades, Flakes and Bifaces Axial Loads, Bending, Shear, Torsion and Their Effects Clues from Fracture Markings and Other Features Some Fractures with Blades and Flakes Splitting of Blades and Flakes Step-In and Step-Out Fractures Incipient Breaks Popouts Some Fractures with Bifaces Overshots and Edge-to-Edge Flakes Amputations Transverse Breakages Fracture Origins Fracture Directions Compression Lips, Curls and Compression Wedges Mist and Related Markings Branching and Lateral Wedges for Blades and Flakes Fracture Velocities Location of Force Application Some Special Breaks Bowties Slices Segmentation Aztec Appreciation of Mechanics