CO2 discharge from the bottom of volcanic Lake Rotomahana, New Zealand. (17th March 2014)

• Record Type: Journal Article
• Authors: Mazot, Agnes; Schwandner, Florian M.; Christenson, Bruce; de, Cornel E. J.; Inguaggiato, Salvatore; Scott, Brad; Graham, Duncan; Britten, Karen; Keeman, J.; Tan, Karine
• Is Part Of: Geochemistry, geophysics, geosystems. Volume 15:Number 3(2014:Mar.)
• Page Start: 577
• Page End: 588
• Publication Date: 2014-03-17
• Subjects: Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 550.5
• DOI: 10.1002/2013GC004945
• Languages: English
• ISSNs: 1525-2027

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>[1] From April 2010 to February 2011, CO₂ flux surveys were performed on Lake Rotomahana, New Zealand. The area has been hydrothermally active with fumaroles and sublacustrine hydrothermal activity before and since the eruption of Mt Tarawera in 1886. The total CO₂ emission from the lake calculated by sequential Gaussian simulation is 549 ± 72 t d⁻¹. Two different mechanisms of degassing, diffusion through the water‐air interface and bubbling, are distinguished using a graphical statistical approach. The carbon dioxide budget calculated for the lake confirms that the main source of CO₂ to the atmosphere is by diffusion covering 94.5% of the lake area (mean CO₂ flux 25 g m⁻² d⁻¹) and to a lesser extent, bubbling (mean CO₂ flux 1297 g m⁻² d⁻¹). Mapping of the CO₂ flux over the entire lake, including over lake floor vents detected during the survey, correlates with eruption craters formed during the 1886 eruption. These surveys also follow regional tectonic patterns present in the southeastern sector of Lake Rotomahana suggesting a deep magmatic source (∼10 km) for CO₂ and different pathways for the gas to escape to the surface. The values of δ¹³C_CO2 (−2.88 and −2.39‰) confirm the magmatic origin of CO₂.</p> </abstract>