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doi:10.2204/iodp.proc.330.201.2014

Introduction

The Louisville Seamount Trail is a submarine structure in the Southwest Pacific Ocean that is ~4300 km in length. The trail formed in response to the movement of the Pacific plate over the Louisville hotspot, tracing the plate’s linear direction of movement. This line of submarine guyots terminates against the Tonga-Kermadec Trench, where this part of the Pacific plate is being subducted under the Indo-Australian plate.

Integrated Ocean Drilling Program (IODP) Expedition 330 sought to gain a greater understanding of motion among hotspots, true polar wander, and patterns of convection within the Earth’s mantle (see the “Expedition 330 summary” chapter [Expedition 330 Scientists, 2012]). Six sites (IODP Sites U1372–U1377) were drilled into the top of seamounts along the Louisville Seamount Trail during the expedition (Fig. F1). Four of the six sites recovered a thin (6.6–13.5 m) layer of pelagic ooze capping the igneous rocks of the seamounts. In an effort to maximize core recovery in these sedimentary sections, a gravity-push method using the weight of the drill string with little or no rotation of the rotary core barrel assembly was employed. No pelagic ooze was encountered at Sites U1373 and U1376, as the holes were spudded directly into cobble-rich hardgrounds. The majority of the sedimentary section at all sites is composed of volcanic sandstone along with varying basalt breccia/conglomerates. Frequently, these clastic sediment packages are mixed with basaltic lava flows and various other volcanic products.

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