Eocene and younger biostratigraphy and lithofacies of the Cascade Seamount, East Tasman Plateau, southwest Pacific Ocean

Geochemistry and significance of basaltic rocks dredged from the South Tasman Rise and adjacent seamounts

“…Several small parasitic cones occur on the flanks of Cascade Seamount, and along the gently rising terraces to each side. Foraminifers in the matrix of a Cascade Seamount volcanic conglomerate provide a minimum mid-Eocene {ca 40-36 Ma) age for the basaltic clasts (Quilty 1997), andLanyon et al (1993) have suggested that Cascade Seamount and neighbouring seamounts to the northeast and south formed over the Balleny hot spot.…”

Late Eocene foraminifers and palaeoenvironment, Cascade Seamount, southwest Pacific Ocean: implications for seamount subsidence and Australia–Antarctica Eocene correlation

“…Cascade Seamount has a history that extends back somewhat earlier in the Late Eocene than indicated by Quilty (1997 The fauna is quite different from coeval southern Australian faunas from similar environments as it lacks many characteristic elements. Strong affinities exist with faunas of New Zealand in the common components.…”

“…This is reflected also in the benthic oxygen isotope record of Shackleton (1986) employed by McGowran et al (1997). Quilty (1997) and Belford (1989) recorded more diverse planktonic foraminiferal faunas including members of the Turborotalia cerroazulensis suite. It is thus likely that planktonic foraminiferal faunas underwent an oscillation complementary to that of the benthic faunas, and that the low diversity of planktonic foraminifers and the absence of the T. cerroazulensis suite from Cascade Seamount are a result of a cool-water interval during this oscillation.…”

“…The sample studied was recovered from the upper reaches of the steep-sided part of the seamount, where the slope approaches 15°in places, and the sample is likely to be in situ. Quilty (1997) recorded Late Eocene -Early Oligocene foraminifers from the study of thin-sections from Cascade Seamount. This age of approximately 38-35 Ma is roughly consistent with the radiometric dates of 36-31.5 Ma (I. McDougall pers.…”

“…The plateau is approximately rectangular, slightly longer in the north-south dimension, and is bounded by east-west (170 km) and north-south (215 km) oriented margins. The seamount stands approximately 2000 m high on the plateau and reaches to within 598 m of sealevel (Quilty 1997). The upper part of the seamount is gently domed from 600 m to 900 m below sea-level, and is then steep sided from 900 m to 1500 m isobaths (Quilty 1997 figures 2, 3;Exon et al 1997 figure 3).…”