Figures from "A Theory for Flake Creation"
A Status Report of Research Begun April, 1997

Tony Baker
December 25, 2003

Before printing this page, scroll through all the figures to insure that all the animations have stop. Figure 3 will not stop, so you must then click the stop button on your browser to stop it. After stopping Figure 3, this page is ready to be printed.

Figure 1 -- Edge view of a 1" by 1/4" thick biface that is firmly supported on the opposite edge from the platform or the bottom in this Figure.

Figure 2 -- Edge view of a 1" by 1/4" biface. Biface is bent because a perpendicular force is applied to the platform. The deflection in magnified 15,000 times.

Figure 3 -- Mathematical representation of a vibrating biface (1" by 1/4") with a fixed edge. The damping portion of the mathematics has been omitted, so it will vibrate until the reader clicks on another figure or turns the computer off. Click stop button on browser to stop this motion.

Figure 4 -- Mathematical representation of a vibrating biface (1" by 1/4") with a fixed edge. It vibrates only one cycle, which is the movement from one position to that same position again. Or, in this case, it is from the starting position to the starting position. The time it takes to move through one cycle is called the period and is measured in seconds.

Figure 5 -- Effects of different initial displacements on the vibrating biface in Figures 3 & 4. The periods are the same, but the displacements and the velocities are different.

Figure 6 -- Animation of 1" by 1/4" biface in Figure 1 being deflected by a perpendicular force to the platform, which is located at the crosshairs. The deflection is magnified 15,000 times.

Figure 7 -- Animation of platform strength being exceeded and the crack beginning in the 1" by 1/4" biface.

Figure 8 -- Animation of making the entire flake with a non-real-world rigid impactor. Same 1" by 1/4" biface used in Figure 1 through Figure 7.

Figure 9 -- Animation of making a feather flake with a non-rigid impactor. Same 1" by 1/4" biface used in Figure 1 through Figure 8. Bulb of force is enlarged by the computer magnification of deflection. Actual bulb size is the size of the scar on the core.

Figure 10 -- Animation of making a feather flake with a non-rigid impactor. Same 1" by 1/4" biface used in Figure 1 through Figure 8, but the impactor is more flexible than the one in Figure 9. Bulb of force is enlarged by the computer magnification of deflection. Actual bulb size is closer to the scar on the core.

Figure 11 -- The motion of the core (not the flake platform) after the crack begins to propagate defines the static and dynamic modes. In the static mode, the core starts immediately towards its at-rest-position (to the left) when the crack begins. This is a result of the loading time being greater that the period of the core. In the dynamic mode, the core has a velocity in the same direction the flake platform is moving and, therefore, it continues in this direction when the crack begins. However, it immediately starts to slow down and ultimately reverses its direction towards the at-rest-position. This is a result of the loading time being less than or equal to the period.

The green arrows represent the direction of movement of the core at the time the crack begins. The red arrows are the direction of movement of the flake platform.



Figure 12 -- A biface under static loading conditions. The red represents the loading time of 0.004 seconds. The blue is one cycle of free response (0.002481 seconds) of the core after the crack initiates. Notice the core immediately reverses its direction toward the at-rest-position at the beginning of the free response. This biface is 3 inches wide by 0.4286 inches thick and fixed at the edge opposite the platform.

These measurements yield a width-to-thickness ratio of 7.0. This is extremely thin, but not without precedence in the archaeological record. Some of the thinner Solutrean laurel leafs have width-to-thickness ratios even higher than 7.0.



Figure 13 -- A biface under dynamic loading conditions. The red represents the loading time of 0.001 seconds. The blue is one cycle of free response (0.002481 seconds) of the core after the crack initiates. At the beginning of the free response, notice the core continues in the same direction it was moving during the loading time. This biface is 3 inches wide by 0.4286 inches thick and fixed at the edge opposite the platform.

These measurements yield a width-to-thickness ratio of 7. This is extremely thin, but not without precedence in the archaeological record. Some of the thinner Solutrean laurel leafs have width-to-thickness ratios even higher than 7.0.




Figure 14 -- The loading regions of a 3" wide biface. The yellow is the static mode region and the purple is the dynamic mode region. The dynamic region is further subdivided into lighter purple and darker purple. In the yellow and lighter purple regions all the flake types except the hinge flake can be created. The darker purple is the region of hinge flakes caused by the second harmonic in the core's vibration.

Figure 15 -- A biface under static loading conditions. The red represents the loading time of 0.0002 seconds. The blue is one cycle of free response (0.0001950 seconds) of the core after the crack initiates. Notice the core immediately reverses its direction toward the at-rest-position at the beginning of the free response. This biface is 3 inches wide by 7.0 inches thick and fixed at the edge opposite the platform. These measurements yield a width-to-thickness ratio of 0.6.

Figure 16 -- A biface under dynamic loading conditions. The red represents the loading time of 0.0002 seconds. The blue is one cycle of free response (0.001418 seconds) of the core after the crack initiates. At the beginning of the free response, notice the core continues in the same direction it was moving during the loading time. This biface is 3 inches wide by 1.0 inches thick and fixed at the edge opposite the platform. These measurements yield a width-to-thickness ratio of 3.

Figure 17 -- A biface under dynamic loading conditions that will yield a hinge flake. The red represents the loading time of 0.0002 seconds. The blue is one cycle of free response (0.002481 seconds) of the core after the crack initiates. At the beginning of the free response, notice the core continues in the same direction it was moving during the loading time. After it reverses its direction, there is a quick, double reversal before it reaches the at-rest-position. This double reversal or hiccup creates the hinge termination. This biface is 3 inches wide by 0.4286 inches thick and fixed at the edge opposite the platform.

These measurements yield a width-to-thickness ratio of 7. This is extremely thin, but not without precedence in the archaeological record. Some of the thinner Solutrean laurel leafs have width-to-thickness ratios even higher than 7.0.



Figure 18 -- Normalized Energy (NE) versus Normalized Loading Time (NLT) of a biface with a constant platform strength.

Figure 19 -- A blade core with three hinge flake scars created by the vibration of the impactor. To create these hinge flakes, the impactor must be a long, narrow billet. The white arrows mark the termination of the hinge flakes.

The blade core in the image is from Les Maitreaux, a Solutrean quarry site in Central France.