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
San Pedro Department, Paraguay points. By the Jejuí River, there is a spring, the Ykua Mandyju, which has white sand beaches. In Itacurubí del Rosario, there is another spring, the Ykua Salas, very frequented by tourists. Laguna Blanca, in the district of Santa Rosa del Aguaray, is an ecologic and tourist point, where there is a lake with completely transparent water. In San Estanislao is the House of Culture and Historical Museum, which was the first Jesuit school, before becoming a barrack for the Marshall López, during the Paraguayan War. San Pedro Department, Paraguay San Pedro () is a department of Paraguay. The capital