page_title: Woodlark Basin
section_title: Tectonics
hierarchical_section_title: Woodlark Basin / Geology / Tectonics
caption_attribution_description: the woodlark basin is boxed in on a map of plate tectonics in the region
context_page_description: The Woodlark Basin is a geologic structural basin located in the southwestern Pacific Ocean and can be found to the southwest of the island country of Papua New Guinea. The basin is an extensional basin that is actively spreading and has a seafloor spreading center. This basin lies between the Indo-Australian Plate and the Solomon microplate and is located at 09°S, 155°E. The Woodlark Basin has an interesting geologic history dating back twenty million years to the initial opening of the basin; the spreading of the basin, however, has occurred within the past three million years. Due to the relatively young age of the basin, many researchers are interested in learning how the basin will continue to develop over time and how the plates will subduct. The subduction of the plates in the Woodlark Basin will be unique because the new crust being formed will be young and warm unlike most crust that gets subducted due to its low temperature and high density.
context_section_description: The Woodlark Basin originally began to open as a sphenochasm with a pole near the tip of eastern Papua about 20 million years ago. A sphenochasm is a triangular gap of oceanic crust separating two continental blocks and converging to a point.  This was caused by left-lateral shear in the region induced by a change in the relative motion pole of the Indo-Australian plate and Pacific Plate. The basin opened only a few degrees at this time, then stopped for a period of time. Then the rifting resumed in the entire basin about 3 million years ago, based on magnetic anomaly data. Then about 1 million years ago, the spreading center in the western basin shifted to the Woodlark Rise. The Woodlark Rise is the northern section of the Woodlark Basin that separates the basin from the bordering Soloman sea to the north. This spreading rift marks the southern boundary of the Solomons Plate which is bounded by subduction zones in the north and east (the New Britain and northern Solomons Trenches, respectively) and in the west by a combination strike-slip rifting (dip-slip) boundary in eastern Papua (New Guinea). A vector triangle solution near the Solomons Trench-Woodlark Rift triple point gives underthrusting of the Solomons Plate beneath the northern Solomon Trench in a northeasterly direction at about 11 centimeters per year. Figure 2 shows each of the tectonic plates surrounding the Woodlark Basin along with the relative plate motion and direction that each plate is moving.
caption: Figure 2: Above is an image of the Woodlark Basin (boxed in area in red) on a map of the plate tectonics in the region surrounding it
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