Hidden Hydrothermal System Discovered Beneath New Zealand's Lake Rotorua

• 06 Feb 2024

Scientists have recently unveiled a concealed hydrothermal system beneath Lake Rotorua, a site with deep Maori cultural significance atop a dormant volcanic crater.

Key Points

• Revelation in Maori Legend: Geothermal Marvels: Despite well-known geothermal features like mud pools and geysers, the lake's bottom remains cooler, challenging previous understanding.
• Shallow Lake Origins: Formed by a collapsed magma chamber after a volcanic eruption, Lake Rotorua is part of the Taupo Volcanic Zone.
• Extensive Mapping: Researchers from GNS Science map 68% of the lake's floor, revealing eruption craters, traces of an ancient river, and a magnetic anomaly.
• Submerged Hydrothermal Activity: Mapping confirms hydrothermal activity extending into the submerged realm of Lake Rotorua, challenging previous knowledge.
• Advanced Technology: The Royal New Zealand Navy assists in using advanced multibeam echo sounder technology for detailed mapping, uncovering unexpected magnetic anomalies.
• Magnetic Anomaly Significance: Magnetic surveys reveal an anomaly, suggesting hydrothermal fluids have altered magnetite into pyrite, reducing the magnetic signal.
• Dynamic Underwater Landscape: Detailed maps expose a dynamic underwater landscape with rising heat and hydrothermal eruption craters.
• Cool Bottom Temperature: Despite intense geothermal activity, the lake maintains a relatively cool bottom temperature of around 14 degrees Celsius due to its vast volume.
• Ongoing Analysis: As researchers analyze data, further discoveries are expected, deepening understanding of the intricate interplay between land, water, and the Earth's crust beneath Lake Rotorua.