Lake Bandung was a prehistoric lake believed once existed between 126,000 and 20,000 years before present, located in and around Bandung city, Priangan highlands, West Java, Indonesia. Today the lake had dried-out and revealed the bottom of a geological basin known as Bandung basin, mostly filled with habitation and industrial areas, paddy fields and orchards. It is believed that this low-lying basin has caused the southern suburbs of Bandung suffers seasonal floodings during rainy season, as the Citarum river that formed the lowermost backbone of the basin overwhelmed and swells.
Bandung basin formation
Bandung basin is an ellips-formed geological basin measuring 60 kilometres east-west, and 40 kilometres north-south, spanned from Padalarang in the west to Nagreg in the east, from mount Tangkuban Perahu in the north to Mount Malabar in the south. The Bandung basin is surrounded by volcanic domes formed during quaternary period in most sides, only western parts is dated older, its stones was formed during neogene period, mostly consist of limestones, creating Padalarang karst mountain. It is suggested that Bandung basin is a multiple volcanic caldera system, created by both volcanic and tectonic activity as there are numbers of tectonic fault crossing the Priangan highland. For example, there is a Lembang fault that runs west-east axis located immediately north of Bandung city under Lembang town. Sedimentation of Bandung basin started 126,000 years before present which suggested that Bandung paleo-lake was first formed during this time.
The formation of Bandung lake went further through the eruption of Mount Sunda. The paleo Sunda volcano — the predecessor of Tangkuban Perahu-Burangrang-Bukit Tunggul volcanic system — is estimated to erupted 55,000 years ago. As the violent plinian eruption caused the conic strato volcano to collapse and blocked the course of Citarum river, forming a natural dam, and turning the basin into a lake known as "the Great Prehistoric Lake of Bandung".
Dried lake
The archaeological findings around Bandung lake discovered numbers of obsidianstone tools, suggesting that the area around the lake was once supported early human habitation that provided water and food for early human population. All of these obsidian tools were discovered on elevation above 700 metres above the sea level, which suggested that the lake surface was once formed around this elevation. According to geological studies, the Bandung paleo-lake sedimentation formation was last formed 20,000 years ago, and started to dried up during that period. The cause of the lake being dried up is a subject of study. It is suggested that either tectonic or volcanic activities in the area, or gradual erosion, has caused the natural dam to collapse, leaked the basin and drained the lake's water into Citarum river.
