The potential for palaeoseismic and palaeoclimatic reconstructions from Lake Tennyson, North Canterbury, New Zealand

ABSTRACT

Lake Tennyson’s basin and sedimentary record were assessed for multiple branches of paleoenvironmental research. A geophysical investigation of the lake depositional setting was supported by physical and chemical analysis of multiple sediment cores. The basin reaches 60 m depth and several subaerial landforms identified were likely deposited from seismic activity. Deformed sediments and turbidites in gravity cores are attributed to one or more large (pre)historic earthquakes, and episodic grain size changes in sediment cores are related to either seismic and/or climatic/meteorological processes. A hummocky slump deposit located on the western lake bed margin is linked to widespread sediment deformation that was likely caused by movement of the Awatere Fault. Radiocarbon dating constrains the most recent major deformation event between the late thirteenth century CE and mid-twentieth Century. Folded turbidites in the stratigraphy suggest multiple sedimentary deformation episodes occurred during the last millennium. Micro-XRF elemental signatures suggest proxies of past water column mixing (windiness proxy) can be reconstructed via identification of changing redox conditions. Records from Lake Tennyson show potential for several palaeoenvironmental research applications, and combining them with basin morphostratigraphy and land-based palaeoclimate and palaeoseismic evidence can enhance understanding of environmental change in the northern South Island.

KEYWORDS:

• Lake Tennyson
• Awatere Fault
• limnology
• Itrax
• CHIRP
• palaeoclimatology
• palaeoseismology
• seismic stratigraphy
• sediment cores
• radiocarbon

Acknowledgements

The authors thank Andrew Willsman (NIWA) for operating the boat used to acquire CHIRP imagery and for taking cores and for producing the Lake Tennyson bathymetric contours.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All ITRAX and bathymetric data will be made available on reasonable request.

Additional information

Funding

This work was funded by the NIWA Strategic Science Investment Fund project ‘Climate Present and Past’ within the Southern Hemisphere Climates and Environments programme in the National Centre for Climate Atmosphere and Hazards. Micro-XRF core scanning was funded from Australian Institute of Nuclear Science and Engineering grant ALNGRA14501.