Distribution, depositional form and geochemical composition of tephra horizons in ODP Sites 186-1150 and 186-1151

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Autores principales: Hunt, John B, Najman, Yanina M R
Formato: Dataset Open Access
Lenguaje:en
Publicado: PANGAEA 2003
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_version_ 1867171363338321920
author Hunt, John B
Najman, Yanina M R
author_facet Hunt, John B
Najman, Yanina M R
collection Datos científicos de ciencias marinas y ambientales
contents Major element geochemical composition was established for 59 tephra horizons from Ocean Drilling Program Sites 1150 and 1151, located in the Japan forearc. These data, encompassing typically between 15 and 30 individual shard analyses per tephra horizon, were used to investigate the degree to which sediment reworking, postdepositional geochemical alteration, and geochemical uniqueness of individual eruptives facilitate or impede the potential for establishing a tephrostratigraphical framework for the Japan Trench, as well as usage of the tephra record to document arc evolution. Evidence was found that hydration (termed phase 1 alteration) of glass shards increases with age in the Pliocene-Pleistocene, but there is no indication that element leaching (phase 2 alteration) has occurred. Post- or syn-depositional differences in preservational style are shown to have no significant bearing on tephrogeochemical homogeneity and suitability for tephrostratigraphical analysis. Overall, therefore, the volcaniclastic record is suitable for investigating medium- to long-term changes in arc geochemistry and, provided consideration is given to the potential for nonunique geochemical signatures, is suitable for erecting tephrochronological frameworks. A limited number of Pleistocene tephra correlations are suggested in furtherance of this framework goal.
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institution PANGAEA
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publishDate 2003
publisher PANGAEA
record_format pangaea
spellingShingle Distribution, depositional form and geochemical composition of tephra horizons in ODP Sites 186-1150 and 186-1151
Hunt, John B
Najman, Yanina M R
186-1150A; 186-1150B; 186-1151A; 186-1151C; DRILL; Drilling/drill rig; Joides Resolution; Leg186; North Pacific Ocean; Ocean Drilling Program; ODP
Major element geochemical composition was established for 59 tephra horizons from Ocean Drilling Program Sites 1150 and 1151, located in the Japan forearc. These data, encompassing typically between 15 and 30 individual shard analyses per tephra horizon, were used to investigate the degree to which sediment reworking, postdepositional geochemical alteration, and geochemical uniqueness of individual eruptives facilitate or impede the potential for establishing a tephrostratigraphical framework for the Japan Trench, as well as usage of the tephra record to document arc evolution. Evidence was found that hydration (termed phase 1 alteration) of glass shards increases with age in the Pliocene-Pleistocene, but there is no indication that element leaching (phase 2 alteration) has occurred. Post- or syn-depositional differences in preservational style are shown to have no significant bearing on tephrogeochemical homogeneity and suitability for tephrostratigraphical analysis. Overall, therefore, the volcaniclastic record is suitable for investigating medium- to long-term changes in arc geochemistry and, provided consideration is given to the potential for nonunique geochemical signatures, is suitable for erecting tephrochronological frameworks. A limited number of Pleistocene tephra correlations are suggested in furtherance of this framework goal.
title Distribution, depositional form and geochemical composition of tephra horizons in ODP Sites 186-1150 and 186-1151
topic 186-1150A; 186-1150B; 186-1151A; 186-1151C; DRILL; Drilling/drill rig; Joides Resolution; Leg186; North Pacific Ocean; Ocean Drilling Program; ODP
url https://doi.org/10.1594/PANGAEA.783505