Microburin technique
The microburin technique is a special procedure for cutting up lithic blades which yields fragments that can be used in the manufacture of utensils. The usable fragments are basically geometric microliths. This technique has been recorded through the Old World, from at least the Mesolithic. It has also been recorded from the later phases of the Upper Paleolithic, as triangular and trapeze shaped microliths have been found from the end of the French Magdalenian although they are very rare. The microburin blow technique has not been found, at present, in the New World.
The technique consists of taking a blade and placing its upper end against a support with a sharp edge. A notch is then made and enlarged using light blows or by pressing the edge of the piece against the angled edge of the support. The notch is enlarged until the lithic blade snaps with a gentle but positive action.
If the technique is carried out effectively, the break should be oblique to the axis of the blade and near to its proximal zone, giving two different pieces: which are called respectively the proximal microburin, which is the smaller of the two pieces and which retains the heel and conchoidal flakes from the original piece; and the trihedral apex, that is the larger part of the blade. The flexion break is also slightly curved and oblique to the faces of the blade: the plane of the break is curved such that it can be seen in the upper face of the trihedral apex and its negative can be seen in the lower face of the microburin.
The microburin is a «characteristic waste product» of this technique, such that no function can be attributed to it, on the other hand the trihedral apex is the raw material used for the manufacture of microliths, such as backed edge blades. Usually the trihedral apex is subjected to the technique again until another flection yields another two pieces, known as the distal microburin and the central part of the worked piece that possesses a double trihedral apex, with converging fracture lines.
This «double trihedral apex» can then be used to form geometric microliths following abrupt retouching of both worked edges. Often the retouching does not cover the whole edge and it is possible to see part of the fracture plain on these microliths. This has allowed us to reconstruct with a great deal of certainty the actions of the artisans who made these microliths
The same microburin blow technique can be used to form other types of non-geometric microliths, such as, for example, the Tardenois tips.