Toca da Boa Vista

{{Infobox cave

| name = Toca da Boa Vista

| map = Brazil

| map_caption = State of Bahia

| label_position = left

| coordinates = {{Coord|-10.162500|-40.859722|name=Toca da Boa Vista}}

| mark =

| mark_width =

| photo =

| photo_caption =

| location = Campo Formoso

| depth = {{convert|50|m|abbr=on}}

| length = {{convert|114|km|abbr=on}}

| survey =

| survey_format =

| discovery = 1987

| geology = Limestone

| entrance_count = 1

| entrance_list =

| hazards =

| access =

}}

Toca da Boa Vista (BA-082) is located within the municipality of Campo Formoso, 11 km east of the town of Lage dos Negros, in the State of Bahia, Brazil. It is part of the Chapada Diamantina mountain range. The area is karstified Salitre formation dolomite bedrock of the Una Group, the brazilian name of the Ediacaran, which is of Precambrian age, about 600 Ma old. This time at the end of the Precambrian was characterized by the beginning of multicellular life, and actually, the sedimentation of limestone was much different from the Mesozoic era. The microorganisms, which later reduced the amount of phosphates and sulfur in the loose sediment on the seabed before diagenesis started, did not yet exist. As a result, the chemistry of this dolomite is unique, and the high amount of phosphor and sulfur caused a unique process of cave formation. Groundwater set the sulfur free which was oxidized by microorganisms and created sulfuric acid, which again dissolved limestone.{{cite web|lang=en|url=https://thesis.library.caltech.edu/14982/9/sanders_cecilia_2022_thesis_draft_21jul2022.pdf|title=Geological and Geochemical Explorations of the Salitre Formation Phosphorite, Eastern Brazil|author=Cecilia Brooke Sanders|access-date=2024-10-29}} This process is called hypogene speleogenesis,{{cite web|lang=en|url=https://www.researchgate.net/publication/286345477_Hypogene_Speleogenesis|title=Hypogene Speleogenesis|author=Alexander B. Klimchouk|access-date=2024-10-29}} where the acid which dissolves the limestone originates from the underground, the rock, instead of from the atmosphere.

The cave system is most famous for an enormous number of prehistoric bones, which were found in the cave. 20,000 years ago an enormous river transported dead animals into the cave, which formed massive deposits of bones. More than 50,000 bones have been excavated until now, among them the bones of huge mammals which are now extinct.{{cite web|lang=en|url=https://www.showcaves.com/english/br/caves/BoaVista.html|title=Toca da Boa Vista|author=Jochen Duckeck|access-date=2024-10-29}} An example is a 6 m long giant sloth, the newest discovery was a turkey vulture (Cathartes aura) in 2024.{{cite web|lang=en|url=https://www.sciencedirect.com/science/article/abs/pii/S0895981124000531|title=First fossil record of a Turkey vulture (Cathartes aura) in northeast of Brazil: Taxonomy, ichnology, and taphonomic history|author=Ronaldo Araujo Leoni, Laís Alves-Silva, João Paulo da Costa, André Vieira de Araújo, Hermínio Ismael de Araújo-Júnior, Mário André Trindade Dantas|access-date=2024-10-29}}

{{As of|2024}} this is the longest known cave of Brazil{{cite web|lang=pt|url=http://cnc.cavernas.org.br/|title=As maiores cavernas do Brasil|author=Sociedade Brasileira de Espeleologia|access-date=2024-10-29}} and it has 114 km of mapped passages. There are obstinate statements that it was the longest cave of the Southern Hemisphere, which are based on an article from 1999.{{cite web|lang=en|url=https://sigep.eco.br/sitio019/sitio019english.htm|title=TOCA DA BOA VISTA, Bahia state the longest known cave in the Southern Hemisphere|author=Augusto S. Auler, Peter L. Smart|access-date=2024-10-29}} At that time the statement was actually correct.