Análisis de la Demanda

The study of the classification of fleece in Isluga as a technical activity demon- strates how herding technology and ideology influence the specific categories of yarn spun in the community and how natural fleece colours are deployed in weaving and plaiting. However, the spinning of yarn responds to a particular set of cultural circumstances involving human beings and herd animals. To examine further the historical particularities of a herding way of life and the implications for changes through time in fibre technology, I will review archaeological evidence from the past. The present chapter examines the emergence of herding societies in the Atacama, and it provides the context for the discussion in Chapter 8 of the yarns and fabrics they produced.

A series of quebradas – deep valleys with intermittent streams – intersect the arid rhyolitic plateau from the high-altitude terrain known as the puna. They descend to the Salar de Atacama, a salt basin with a few freshwater lakes seasonally occupied by flamingos. This is the environment that forms the setting for the archaeological sites that have produced the yarns and fabrics of camelid fibre analysed in the Appendix and Chapter 8. It is important to understand that this rugged and all too arid landscape that bears the imprint of human activity from the past is not an unchanging backdrop to those activities: in other words, they take place in a meaningful environment. However, detailed reconstructions of the Atacama environment cannot at present be securely correlated with changes in the archaeological record. The information currently available for reconstructing palaeoclimatic conditions in the region is somewhat contradictory, as will be made clear below.

The present chapter focuses on the Tulan and Purifica Quebradas1_{that have,} for many millennia, formed part of a hunter-gatherer and herding way of life. Pastoral activities are a notable characteristic of these and other quebradas that drain into the Salar de Atacama. The people have added flocks of sheep and goats alongside their herds of llamas. Herders in the Atacama are even more constrained by temporal shortages of adequate pasture than are their counterparts in Isluga. This has given rise to a lifestyle with complex, nomadic, seasonal cycles of movement.

The streams in many of the quebradas are intermittent and they peter out before reaching the Salar. They have cut down into the sloping, rugged landscape from

the high terrain, the puna proper, with its chain of extinct and active volcanoes and highland lakes that run along the length of the Chilean–Argentinian border. The puna is characterized by steppe-like vegetation dominated by the bunch grass Paja brava, while the land bordering the valleys tends to be sparsely covered by shrubs at about 3,000 m asl. However, the valley floors immediately adjacent to streams and watercourses do provide more abundant pasture of grasses and reeds. At a lower level, near the Salar, there are flat areas of vegetation known as vegas.2 The extreme dryness that characterizes the climate of this area is due to an almost total lack of precipitation from April to November. Summer rains and snow fall between December and March at altitudes above 3,000 m. Only occasionally does it rain over the Salar and town of San Pedro de Atacama. According to Popper (1977: 8), the aridity is due mainly to a stable subtropical high-pressure zone over the area. During the summer months, an equatorial front of low pressure moves in over the highlands, thus producing rain and snow sometimes called the Bolivian winter. Other factors involved in maintaining the aridity include the cooling effect of the Humboldt Current on the humid air masses of the Pacific Ocean. During the winter months, as temperatures drop, the air mass condenses and it forms thick fog on the coast, but any eastward movement of this moisture is obstructed by the coastal ranges of hills. Additionally, the chain of Andean mountains blocks any humid air masses from moving in from the Atlantic (ibid.: 9).

The low humidity level produces diurnal temperature changes, with a daily variation between high and low temperatures reaching up to 35°C on occasion, depending on altitude (ibid.: 9). Winter, the coldest period of the year, is between April and September, the cold being most intense from July to August. Snow may fall during this period at high altitudes.

Another feature of the area is the occurrence of strong winds from the south- west, especially in October and November, when they may reach more than 100 km per hour. Fine sediments whipped up from the Salar act as agents of erosion, and the winds also increase the high evaporation rates (ibid. 1977: 9).

The Tulan Quebrada is one of the most southerly of a number of valleys draining into the Salar. At its northern end, the Salar de Atacama is fed with water from the San Pedro and Vilama rivers. Further upstream, the Vilama river is joined by one of its tributaries, the Puritama, at Guatin, which is at 3,200 m asl, where irrigated fields are cultivated. The vegetational cover is more abundant here, and there is more pasture, which nowadays is exploited by donkeys, herds of llamas, and flocks of sheep and goats. The Puritama river is, in turn, joined by a tributary, the Purifica (or Puripica) river, which further upstream has cut down into a steep-sided gorge, and above which is located the site of PU 1. The landscape here is characterized by the frequent occurrence of very tall and imposing cardon cacti (Trichocereus atacamensis), which are exploited by the people of the area as a substitute for wood in roof construction and as planks for doors. This region is said to be more humid than the Tulan Quebrada. It certainly has the appearance of being moister, an impression also shared by T. Holden (personal communication) (plate 7.1). Despite the relative moistness of the Purifica Quebrada, few archaeological sites have been identified. In contrast, well over one hundred sites

have been registered in the Tulan Quebrada. Since PU 1 is the site that evidently saw the domestication of camelids over 4,000 years ago, the question arises whether present-day climate is different from that which prevailed in the past. It is particularly important to explore this issue, given that both Browman (1974) and Hesse (1982b) have argued that increasing aridity encouraged hunters to start herding camelids as a source of ‘tame meat’.