The decline in forest cover in the Lake Titicaca Basin beginning during the Early Formative intensified throughout the Formative Period. Between 2500 - 800 cal. BCE a decline in fine particulate charcoal was detected in a lakecore drawn from the southern end of Lake Titicaca's Lago Grande(Paduano, et al. 2003: 274). The pollen and charcoal record indicates thatforest cover finally disappeared around AD0, coincident with population increases and resource pressure associated with Late Formative Period socio-economic intensification.
The obsidian circulation during the Late Formative shows distinct patterns in the Titicaca Basin and in Cusco. In the Titicaca Basin, the diversity of sources is reduced, with virtually all the material coming from Chivay and Alca, and the Alca samples are primarily affiliated with a single period at Taraco. Even at the site of Qillqatani, the diversity is reduced as compared with the previous Middle Formative level (Qillqatani Formative C). Current evidence suggests that the economic circulation was more integrated and that it was probably under some form of control by the dominant regional centers of this time. The furthest confirmed evidence of Chivay obsidian transport is from among Late Formative contexts at Kallamarka and Khonkho Wankane.Yet, diagnostic evidence from Titicaca Basin Late Formative polities in the Colca valley area is scarce. Part of the difficulty in understanding the Formative at the Chivay obsidian source area is that the Formative ceramic sequence in the Arequipa highlands is still being refined.