Gruta do Lago Azul

写真: Tiziana Paulina Sepulveda Henao · CC BY-SA 4.0

立入制限あり · 公開情報のとおり 2022-07-13 State Natural Monument (IMASUL management plan approved 2022); the cave was ceded to the municipality of Bonito in 2021, which runs guided visits. The 2012 state authorisation covered contemplative visits only, with a local registered guide and a Bonito voucher único. No public diving offer was found. アクセスルールは変わることがあります。出発前に土地所有者または管理機関に必ず確認してください。

ドキュメント済み別名: Blue Lake Grotto, Monumento Natural da Gruta do Lago Azul, Gruta do Lago Azul Natural Monument

測量済み延長

未公開

記録上の深度

90 m (295 ft)

掲載されている入口

A 2002 magazine article gives the lake as 90 m deep; no published survey was found, so treat this as approximate.

A protected limestone cave near Bonito whose sloping main chamber ends in a clear underground lake, where divers found Pleistocene mammal bones in 1992. Public visits are guided walking tours; no public diving offer was found.

Gruta do Lago Azul is a limestone cave about 21 km from Bonito. A circular entrance about 40 m across lets sunlight into a large chamber whose floor slopes steeply down to an underground lake more than 50 m long. When sunlight strikes the water, for part of each year, the lake turns an intense blue that gives the cave its name. It is one of Bonito's best-known landmarks and was listed by Brazil's national heritage institute IPHAN in 1978.

In 1992 a team of Brazilian and French divers found bones of extinct Pleistocene mammals on the lake floor, including giant ground sloths, armadillos and sabre-toothed cats. Sources give their age as roughly 10,000 to more than 12,000 years. The lake is also home to Potiicoara brasiliensis, a blind, unpigmented crustacean about 7 mm long first identified there in the late 1980s.

The cave is part of a state Natural Monument whose management plan was approved by the Mato Grosso do Sul environment institute IMASUL in July 2022. Because caves are federal property, the federal government ceded the cave to the municipality of Bonito in 2021 for 20 years, and the municipality runs the visits.

Visits are guided walking tours. The state visitation order reviewed for this record (2012) covered contemplative visits only and said nothing about diving, and no current public diving offer was found. The lake is therefore listed here for its scientific importance, not as a dive site.

なぜ重要か

Divers' finds on the lake floor in 1992 revealed a deposit of Pleistocene large-mammal bones, including giant sloths, armadillos and sabre-toothed cats. The lake is also known for cave-adapted aquatic fauna, including the 7 mm crustacean Potiicoara brasiliensis; a 2002 report said eight troglobitic (cave-restricted) aquatic species had been identified in Bonito's caves.

コンディション

Sunlight reaches the lake in the morning in some months; sources give September to February for the strongest blue colour. Visits are walking tours, so water conditions are not published.

公表資料からの一般的な範囲であり、現在のコンディションではありません。

測量と探査の歴史

1924	The cave was found by Terena Indigenous people, according to a show-cave reference. [5]
1978	IPHAN listed the cave as protected heritage. [4] [6]
1985	The first gate restricting unlimited tourist access was installed. [7]
1992	Brazilian and French divers found Pleistocene mammal bones on the lake floor. [3] [5]
2012-12-20	IMASUL authorised contemplative tourist visits with a daily cap of 305 visitors. [1]
2021-01-20	The federal Secretariat of Union Property authorised ceding the cave to the municipality of Bonito for 20 years. [4]
2022-07-12	IMASUL approved the Natural Monument's management plan. [2]

入口とダイブサイト

One large circular entrance, about 40 m across, reached on guided tours.