Regional Changes within the Inka Frontier Zone
The Multiethnic Valley of Oroncota
In this chapter, the results of my archaeological survey in the western Valley of Oroncota are presented in order to assess the shifts in the settlement patterns and changes prompted by the Inka conquest. This region is at the western portion of the Southeastern Inka frontier and, therefore, within the frontier zone. While conducting this portion of the research, we were particularly interested in understanding whether the Inka centers were placed in preexisting population centers and if their effect was significant on the surrounding areas. Associated themes included a reconstruction of distribution of Inka status materials in the indigenous settlements and imperial facilities, and the differential access to Guarani-Chiriguano and eastern lowland materials. Before we turn our attention to this discussion, let me first describe the regional ecology and introduce the relevant eth- nohistorical narratives of this valley in the Inka provincial politics.
The Oroncota Valley sits to the west of the Cordillera Real mountain range, at the confluence of the Pilcomayo and Oroncotilla Rivers (Figure 4.1). In the past, this region was incorporated as the inner portion of the Southeastern Inka frontier area. Two main ecological zones are dominant (Figure 4.1). The first comprises the steep mountains and deep canyons, which are prone to intensive erosion. In fact, the mountain sediments— often formed by shale, limonite, sandstone, and quartzite—are easy targets of erosion, which results in a low water-retention capacity (Asebey Morales 1994a, 1994b). One prominent geologic feature is the Pucara Plateau, an enormous, triangular-shaped barren plateau with more than
Figure 4.1. Hydrology and agricultural potential of the Oroncota region.
1,000 m of elevation. By comparison, the second zone contains the alluvial fertile plains along the lower Pilcomayo River and tributaries (Mendez Mendivil 1994; Mendez Mendivil and Asebey Morales 1994). Because this alluvial floor is constantly flooded, this zone is exceptionally rich in soil sediments optimal for agriculture.
Hydrologically, the Oroncota Valley belongs to the Pilcomayo River system, part of the major western La Plata watershed in the Southern Andes. Today, the Pilcomayo waterway is a main source of transportation between Bolivia and Argentina and serves as a natural divide between the Bolivian departments of Potosi and Chuquisaca (Cortes R. 1994). Similar to adjacent southern valleys, Oroncota is temperate. The low rainfall levels contribute to vegetation dominated by xerophytic plants like cacti, thorny bushes, and trees like molle and chanar (Mendez Mendivil 1994; Mendez Mendivil and Asebey Morales 1994; Montes de Oca 1989). Since the pre-Columbian era, the alluvial floor was the focus of agricultural intensification (Agreda Corrales 1994:21). In the later Spanish Colonial period, the Valley was famous for its lush vineyards. More recently, local Quechua residents cultivate a myriad of products, including corn, peanuts, grapes, cherimoyas, oranges, and tangerines for the regional markets (Julien 1995).