Geology of Paraguay Basin. These tholeiites were erupted in the Early Cretaceous in association with the initial opening of the South Atlantic. The Cretaceous volcanism did also created minor outcrops of potassic alkaline volcanics in a graben structure developed between Asunción and Villarrica and in Amambay Department. Cretaceous volcanism did also left small units of sodic alkaline rocks in Misiones Department in southern Paraguay. 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
Paraguay Paraguay Paraguay (; ; , ), officially the Republic of Paraguay (; ), is one of only two landlocked countries in South America (the other is Bolivia). It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the country from north to south. Due to its central location in South America, it is sometimes referred to as "Corazón de Sudamérica" ("Heart of South America"). Spanish conquistadores arrived in 1524 after navigating northwards from the