Alkalic to tholeiitic magmatism near a mid-ocean ridge: petrogenesis of the KR1 Seamount Trail adjacent to the Australian-Antarctic Ridge

Magnetic Constraints on Off‐Axis Seamount Volcanism in the Easternmost Segment of the Australian‐Antarctic Ridge

“…Figure 8b shows a comparison of the seamount ages constrained by this study with the radiogenic ages for the basalt lavas dredged from seamounts E2 and E3 (Yi et al., 2020). The geomagnetic ages of seamounts E2 and E3 overlapped with the given uncertainty of radiogenic ages (Figure 8b).…”

“…Although there are no rock samples from the SC-1 seamounts to test the petrological prediction on off-axis volcanism (Davis & Karsten, 1986), the alkali basalts from seamounts E2 and E3 formed at ∼10 km off-axis exhibit radiogenic Pb and mildly enriched Sr and Nd isotopic compositions (Yi et al, 2019(Yi et al, , 2020. The radiogenic and isotopic enrichments observed at SC-2 might have originated from a magma source that reflects a small degree of partial melting with a lower fraction of heavy isotopes (e.g., Davis & Karsten, 1986).…”

“…Red, green, and blue represent the seamounts in the eastern, central, and western KR1, respectively. (b) Comparison of the magnetically constrained seamount ages in this study with the radiogenic (e.g., [U‐Th]/He and K‐Ar) ages of the basalt samples from seamounts E2 and E3 (Yi et al., 2020).…”

Geomorphological and Spatial Characteristics of Underwater Volcanoes in the Easternmost Australian-Antarctic Ridge

“…In KR1, the basalts collected from seamounts E2 and E3 in SC-2 exhibit radiogenic and isotopic enrichment [29,30], which implies that the alkalic basalts from SC-2 originate from magma with low-fractionated heavy isotopes [9]. The compositional heterogeneity in the upper mantle can facilitate melt buoyancy and a small-scale upwelling at a considerable distance from the ridge axis [7,[9][10][11][12].…”