LATE TRIASSIC FORAMINIFERA FROM SOUTH ISLAND AOTEAROA (NEW ZEALAND)

Foraminifera are important microfossils for paleoenvironmental reconstruction, geochemical analysis, and biostratigraphy, but very few previous studies have documented the diversity, preservation, and abundance of foraminifera in Late Triassic marine deposits in New Zealand. Here we present results of a survey of foraminifera liberated from the marine volcaniclastic deposits in the Hokonui Hills of South Island, part of the Taringatura Supergroup. We identified at least three different foraminiferal genera, including Astacolus, Eoguttulina, and Marginulina. The South Island Aotearoa microfossil assemblages comprised mostly agglutinated foraminifera, with a few original tests composed of calcium carbonate that has since been replaced in the fossilization process. Electron diffraction spectroscopy revealed that the foraminifera tests are now composed of alumino-silicate clays, likely remineralized from the surrounding siliciclastic matrix. This preservation style is comparable to the associated invertebrate macrofossils, including brachiopods, bivalves, and rare echinoderms that also do not contain original or replacement carbonates. The environmental ranges for the identified foraminifera are fairly broad, including shallow to offshore environments.