Geology of Paraguay

The country of Paraguay lies geologically at the borderzone between several cratons. Due to thick Cenozoic sediment cover and regolith development few outcrops are available in Paraguay. East of Paraguay River that Precambrian and Early Paleozoic crystalline basement crop out mainly in the heights of Caapucú and Apa. The geological processes that have shaped Paraguay's bedrock and sedimentary basins are diverse including rifting, marine sedimentation, metamorphism, eruption of flood basalts and alkaline potassic volcanism.

Caapucú High (formerly called Precámbrico Sur and Saliente del Pilar) is the Northwesternmost outcrop of Río de la Plata Craton. The rocks found in the Caapucú High include porphyritic granitic rocks, orthogneisses, paragneisses, amphibolites, migmatites, talc schists and rhyolite dykes. During the Brasiliano Cycle (576-480 Ma ago) the area of the Caapucú height suffered a major magmatic event.

The formations at the Apa High include metamorphosed limestone of Vendian Age and granites, metasediments, mafic gneisses and granitoid-pegmatititic intrusvies of Late Proterozoic age. The Apa high is often considered the southernmost outcrop of the Central Brazilian Shield (also called Guaporé Shield) which is sometimes considered to form one sole shield (or at least craton) with the Guyana Shield called the Amazonian Shield.