Exchange

The lake level rise in 250 B.C. seems to have been of particular significance. I argued in Chapter 6 that sometime in the later MF, around 450 B.C., Lago Wiñaymarka became mostly dry. This fact made possible a shorter trade route between the Western Titicaca Basin and the yungas than the one used today (see Figure 6.8). This shorter trade route would have passed along the Taraco Peninsula. The new proximity of the Taraco Peninsula villages to what undoubtedly was one of the principal regional trade routes is reflected in the large amount of imported exotic goods in these settlements - archaeologically represented mostly by imported stone hoes.

The lake level rise at the beginning of the LF1 (250 B.C.) would have had the effect of of shifting the trade route back to its prior (and recent) path, passing through the Tiwanaku Valley and crossing the Desaguadero River - probably flowing for at least part of the LF1 - at the modern Peru/Bolivia border. This had the effect of isolating the Taraco Peninsula communities, and neutralizing any advantage which they may have gained from their previously strategic location.

The fate of the MF exchange network in the LF1 and LF2 is a difficult issue. Since MF exchange was identified primarily through basalt hoes - the most common exotic items encountered archaeologically in the southern Titicaca Basin (see Chapter 6) - it should be interesting to analyze the frequency of lithic raw material on the LF1 in comparison to the MF. However, the TAP excavations at Chiripa sampled no intact LF levels. The only available data which bear on this question are Janusek's excavations at various Pampa Koani sites ([Janusek 2002,Janusek and Kolata 2002]). These are presented in Table 7.1.

Table 7.1: Raw material frequency of lithic agricultural implements on the Pampa Koani

Period	Site	%quartzite	%slate	%other
MF	Qeyakuntu	49	14	37
LF	Qeyakuntu	55	36	9
LF	Urikatu	0	100	0
LF	Kirawi	2	88	10

In the table, the ``other'' category, according to Janusek, consists primarily of ``andesite and basalt''. Since his excavations are located very near to the Taraco Peninsula I will assume that the lithic assemblage is similar, and that the ``other''category consists almost entirely of imported basalt. Viewed this way, Janusek's data indicate a dramatic decline in imported lithic materials in the LF, from almost 40% of the entire assemblage in the MF, to 10% or less. This is entirely consistent with my own surface collection results, reported in Table 6.2.

This decline in exotic raw material frequency indicates either

1. an overall decline in regional trade, probably related to the formation of the Pukara polity in the northern Titicaca Basin, or
2. increased relative isolation of the Taraco Peninsula/Pampa Koani, resulting from the 250 B.C. lake level rise and subsequent relocation of the yungas trade route,

or both. In any case, it seems likely that the significance of regional exchange for the Taraco Peninsula communities was greatly decreased. I will discuss the importance of this fact at the end of this chapter.