Western Gondwana underwent a steady drift from mid-latitudes (~50°S, Early Carboniferous) to lower latitudes (<40°S) by Late Carboniferous time, and glacial deposition had ended in Bolivia by the early Pennsylvanian (Morrowan). At this time, carbonates and evaporites were being deposited across the Perú-Bolivia Basin. The Pennsylvanian and Permian Titicaca Group represents an Andean transgressive marine to restricted carbonate and regressive red bed megasequence (Cuevo Super-sequence or Subandean Cycle). The transgressive part of this Pangean first-order sequence records inherited basement controls and ephemeral pericratonic seaways into the interior of a western landmass. The well-dated Copacabana Formation records many high-frequency sequences and meter-scale cycles that form larger, third- and second-order composite sequences in the central Andes. Diverse carbonates, compositionally immature but texturally more mature arkosic and lithic sandstones, shales, tuffs, and evaporites characterize Copacabana Formation lithologies, which have been dated using foraminifera, fusulinids, conodonts, and palynomorphs. Estuarine barrier sands and cross-bedded, fossiliferous marine sandstones with limestone lithoclasts were derived by reworking of semilithified Copacabana rocks during lowstands and transgressive flooding events. Sedimentation rates in Bolivia were relatively low (7–25 m/m.y.) compared with the thicker and shale-rich Copacabana Formation in Perú. Stacked transgressive systems tracts and highstand systems tracts with significant hiatuses formed in open-marine and restricted to semiarid coastal depositional systems. Twelve second- and third-order, 30–100 m composite sequences have incisement or protosol development above marine limestone of the underlying sequence; extensive siliciclastic lowstand and/or transgressive shoreline facies occur above these sequence boundaries. Thick accumulations of progradational carbonate characterize the highstand systems tracts. More distal subtidal ramp sequences (well-developed in the Cochabamba and northern Subandes areas) are shale-cored with fossiliferous packstone-grainstone caps, but they lack evidence of subaerial exposure or disconformity. Small, meter-scale shallowing-upward parasequences and internal autocyclic, icehouse facies mosaics comprise the larger Copacabana composite sequences. Pennsylvanian sequence boundaries (occurring as a result of glacial drawdowns) occurred at ca. 318 Ma, 311 Ma, 309 Ma, 308 Ma, and 306.5 Ma. Permian drawdowns occurred at 299 Ma, 293 Ma, and 283 Ma.

Two pulses of granitoid magmatism occurred in the Cordillera Real in the eastern Andes of Bolivia (La Paz department), one in the Middle to Upper Triassic and the other in the late Oligocene to Miocene. This magmatism occurred along the southward extension of the rift-controlled inner magmatic arc of the southeastern Andes of Peru. The peraluminous chemistry, the high but restricted silica range, and the low CaO and MgO contents of these “S-like” plutonic rocks suggest that they formed by fractional crystallization followed by variable assimilation of supracrustal rocks. The Pb isotopic data of Tilton and others (1981) supports a mantle component in the Cordillera Real melts. The Cordillera Real granites are characterized by high tin contents. Geochemical indicators such as TiO 2 content and Rb/Sr, Rb/Ba, and Mg/Li ratios suggest that the tin was introduced by assimilation during the late and post-magmatic stages of the plutons.