KNAPPING FEATURES


knapping features
Various features can be observed on some artifacts that indicate errors in preparation or judgment on the part of the knapper. Identifying these occurrences can assist in forming a picture of the knapper's individual abilities. For example, all knappers occasionally misjudge a blow but indications of repeated poor judgment can denote the work of a beginner or a novice (Bodu et al 1987; Pigeot 1990; Ploux 1991).

The following are some knapping errors and features that indicate poor core preparation or maintenance.

hinged flake
A hinge detachment occurs when the plane of the fracture, "turns abruptly outwards and leaves the edge of the flake blunt and smoothly rounded. These fractures are particularly liable to be mistaken for polishing ..." (Trustees of the British Museum, 1968, 29).

Hinging occurs because the angle of detachment is incorrect (i.e. at 90 degrees) and the face of the core is concave or straight. (Se Cotterell and Kammiga 1987, 700-701 and Crabtree 1982., 37).
It is the exact opposite of a plunge fracture.

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hinged negative removal
This occurs as the characteristic "hook" on the face of a core when a hinged flake has been detached. It requires an intentional correction blow to be applied to rid the core face of this feature, which will continue to occur repeatedly if the platform and the face of the core are not adjusted. As noted by Cotterell and Kammiga 1987, 701. hinged flakes and hinged removals on the face of a core are "undesirable" elements.

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plunge
Plunging occurs when the fracture plane turns abruptly towards the centre of the piece and takes away part of the core. The two main characteristics are a very concave ventral surface, and a thickening at the distal end. (Tixier 1974, 19). This occurs when the angle of detachment is too acute on the platform and the face of the core is too convex (Cotterell and Kammiga 1987, 701). (Also see Roche and Tixier 1982, 72-73). This is the exact opposite of hinged flake.

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plunged negative removal
The negative detachment from a plunged removal leaves a highly characteristic scar. When this occurs on a blade core it is often detected by the full removal of the opposite platform. This is a knapping error, which, to quote Tixier 1974, 19, anyone who tries flaking experiments will discover sooner or later to their cost.

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miss-strike rings
A miss-strike ring is an opaque circle that can be found near the point of impact or percussion on the butt of a detachment or on the core platform. It occurs when a blow is struck which is not sufficient to detach a flake or a blade and "appears as a small circle, probably surrounded by a patch of discolouration due to the interference of the crack with the passage of light through the flint"
(Trustees of the British Museum, 1968, 26).

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feathering
"A technique which produces a flake which terminates in an edge with a minimal margin. Produces blades or flakes with edges and distal ends which are very sharp. Feathered edge leaves slight ridges on the objective piece, a characteristic of precision collateral flaking" (Crabtree 1982, 33-36). Although feathered edges are thin and sharp they are also easily broken. (Also see Owen 1988, 220).

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step fracture
A flake or flake scar that terminates abruptly in a right angle break at the point of truncation. Caused by a dissipation of force or the collapse of the flake (Crabtree 1982, 53). Cotterell and Kammiga 1987, 700 claim it can be caused by the flake buckling during detachment.

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