Lake Tagimaucia Montane Lake as a Potential Late Holocene Environmental Archive in Fiji's Volcanic Highlands 1

Lake Tagimaucia, a montane volcanic lake on Taveuni Island, is Fijis only high-elevation lake. This study examined a lacustrine sediment core to explore the lakes potential as a palaeoenvironmental archive through the Late Holocene. Dating reveals no simple age-depth relationship due to sediment age...

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Bibliographic Details
Published inPacific science Vol. 76; no. 3; pp. 289 - 311
Main Authors Terry, James, Singh, Kunal, McKeown, Michelle
Format Journal Article
LanguageEnglish
Published Honolulu University of Hawaii Press 01.07.2022
Subjects
Archives & records
Bulk density
Catchment area
Charcoal
Drought
El Nino
El Nino phenomena
Fires
Holocene
Lake sediments
Lakes
Organic matter
Peat
Peatlands
Precipitation
Rain
Sediment
Sedimentation & deposition
Sediments
Southern Oscillation
Stratigraphy
Summer
Swamps
Vegetation
Volcanic eruptions
Wetlands
Winter
Vanuatu
Fiji
South Pacific
Taveuni Island
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Summary:Lake Tagimaucia, a montane volcanic lake on Taveuni Island, is Fijis only high-elevation lake. This study examined a lacustrine sediment core to explore the lakes potential as a palaeoenvironmental archive through the Late Holocene. Dating reveals no simple age-depth relationship due to sediment agereversals. However, phases of fire activity are evidenced by two distinct charcoal bands. Catchment burns were probably related to significant ENSO-driven drought, although fire ignition by volcanic eruptions on Taveuni cannot be ruled out. Above the dominant charcoal band, the sediment profile exhibits notable positive shifts in organic matter, bulk density, S13C, and C:N ratio. These peaks suggest a phase of accelerated catchment erosion, possibly triggered by post-burn instability. We introduce a conceptual model to explain the influence of sedge peat swamps on lake sedimentation processes. Surrounding sedge-dominated peatlands have extensively encroached Lake Tagimaucia. Floating peat mats, gradually accumulating through time, act as a repository of organic material that is stored directly on the lake surface. Episodes of drought and fire release old organics directly into the lake itself, probably contributing to the complex chronological sequence in the Late Holocene stratigraphy.
ISSN:0030-8870
1534-6188
DOI:10.2984/76.3.4