A morphological and discriminant study: darts and arrows in the Andes between 6200 and 1760 years cal BP in Los Morrillos, San Juan (31°S)

Abstract

We present a functional study of lithic projectile points from an Andean region (31°S) and chronologies between 6200 and 1760 cal yr BP. The sample is from the site Los Morrillos, Gruta 1 and 2 (San Juan, Argentina). We organize the occupational history of the site into three phases: 1) 6200-5000 years cal BP, 2) 2530-2230 years cal BP and 3) later than 2000 years cal BP. We seek to identify different weapon systems, to refine the chronology of entry of the bow and arrow and to evaluate different methodological proposals for discriminant analysis. We evaluated several metric variables: perimeter and cross-sectional area, mass, aerodynamics, shoulder width and stem or neck width). We recorded dart points throughout the chronological sequence. Within this type of projectile, we distinguish two groups: a) larger and heavier darts and b) smaller and lighter darts. The latter could be part of systems that the use feathering and/or high velocity projectiles. Large and small darts are recorded in the first phase. Large darts have an important representation throughout the occupational sequence. Small darts predominate in phase 2. The earliest arrowheads at the site were recorded in this phase (2530 cal yr BP) and continue in phase 3, which represents the co-existence of weapon systems. These results are coherent with the macro-regional trends that propose the arrival of the bow and arrow at 29°S ca. 3000 cal yrs BP and at 37°S ca. 1000 cal yrs BP.