Taftan (volcano) published in 1897 indicated the absence of very fresh lava flows but the authors inferred from the fresh ash that volcanic activity had occurred during the present geological epoch. That the name "Taftan" may be derived from an ancient Iranian word "taft" for "semi solid liquid material" could indicate that effusive activity was witnessed by the people of that time period around the volcano. Eruptions are recorded in 1902, 1970 and 1993. A report of smoke emission in 1877 may have confused clouds for volcanic activity. In 1914, the volcano was described to be "belching out clouds of smoke", although
Nova Iguaçu Volcano underlain by pyroclastic rock. This rock originated from rock fragments created by a volcanic explosion. The valley is made up of trachyte, another igneous rock with massive texture. The pyroclastic rock was the main justification of the Nova Iguaçu Volcano hypothesis. The existence of a volcano at Nova Iguaçu was proposed by geologists Viktor Carvalho Klein and André Calixto Vieira in the 1980s. Klein and Vieira based their discovery on the presence of pyroclastic rocks (including volcanic bombs) and the existence of a volcanic crater. They believed the pyroclastic rock to be pyroclastic flow deposits, constituting an “extraordinary well-preserved complete