Abstract
Constraining the age and depositional characteristics of the Saunders Ash, Mt. Taranaki, New Zealand
Abstracts with programs - Geological Society of America, Vol.56(5)
Geological Society of America, 2024 annual meeting; GSA connects 2024
09/2024
DOI: 10.1130/abs/2024AM-404204
Abstract
The Saunders Ash is pyroclastic density current (PDC) unit located on the NW flank of Mt. Taranaki, New Zealand, for which the precise timing and methods of emplacement remain to be determined. The deposit is believed to represent an unusually explosive eruption as one of a rare set of long-runout PDCs in the region, however the position of the Saunders Ash in the regional stratigraphy as well as the timing and relation to volcanic collapse events is uncertain. New radiocarbon dating has been accomplished to improve upon the previously existing debated age of the Saunders Ash. Two new radiocarbon ages indicate that original age estimates were too young, leading to the ability to pinpoint the deposit more accurately within regional stratigraphy through reevaluation and recalibration of existing (super 14) C ages. Focus has been placed on plagioclase crystals present throughout the Saunders Ash sample suite, as the slow diffusion of major elements due to coupled substitution make it a strong recorder of magmatic processes. SEM investigations of individual grain mounted plagioclase crystals were conducted to determine if chemical and/or mineralogical temporal variations occurred spanning the nearly equal 3.5 m thick outcrop located 13 km from source. SEM back scatter imagery results indicate that crystal textures which preserve evidence of multiple dissolution/growth episodes, vary throughout the section. Crystals were visually sorted into four categories based on specific rim/core, oscillatory zoning, sieved texture, and dissolution texture characteristics. SEM imagery will be paired with EMP analysis to quantify anorthite variations across representative crystals of each textural type and determine minor element (Fe,Mg) contents. Transects will be utilized to further understand crystal chemical/textural variation to determine potential changes in magmatic plumbing system and eruptive characteristics. This work aims to contribute to the effort of understanding the details and progressive development of the Mt. Taranaki magmatic plumbing system to aid in forecasting future potential eruptive scenarios.
Details
- Title: Subtitle
- Constraining the age and depositional characteristics of the Saunders Ash, Mt. Taranaki, New Zealand
- Creators
- Samuel Hudziak - University of Iowa, Earth and Environmental Sciences Department Iowa City, IA USA United StatesDavid PeateIngrid Ukstins
- Resource Type
- Abstract
- Publication Details
- Abstracts with programs - Geological Society of America, Vol.56(5)
- Conference
- Geological Society of America, 2024 annual meeting; GSA connects 2024
- DOI
- 10.1130/abs/2024AM-404204
- ISSN
- 0016-7592
- Publisher
- Geological Society of America (GSA)
- Alternative title
- Geological Society of America, 2024 annual meeting; GSA connects 2024
- Language
- English
- Date published
- 09/2024
- Academic Unit
- School of Earth, Environment, and Sustainability; Honors Program
- Record Identifier
- 9984966699402771
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