analyses of the seafloor produced ages of 118–83 Ma. The HALIP is widely thought to have originated from a mantle plume, and the igneous activity of the province often tracked along a similar path as the Icelandic hotspot. Magmatic provinces The HALIP is divided into several magmatic provinces. These provinces are divided by location, igneous rock composition, and the formations present. Svalbard In the Svalbard province, the HALIP is expressed as an extensive system of alkaline intrusive doleritic rocks. The intrusions largely appear in the form of sills that can reach thicknesses of and continuously extend for up to laterally. The basaltic rocks found in Svalbard have an intra-plate composition and are thought to originate from a source near the Alpha Ridge. The Svalbard province is also closely associated with the Franz Josef Land province (discussed below). The two provinces combined cover an area of approximately . Franz Josef Land The Franz Josef Land province is closely associated with the Svalbard province. Franz Josef Land is located approximately east of Svalbard and contains igneous rocks of very similar composition to those of Svalbard. However, the archipelago is scattered with a prominent swarm of southeast trending dikes. Extensive sills and volcanic flows can also be found in the region, as well as a few dikes of other trends. The timing of the Franz Josef Land formations and the Svalbard formations is thought to be nearly identical, furthering the evidence for a large initial plume head model for the HALIP. Sverdrup Basin The Sverdrup Basin province spreads across the Canadian Arctic Islands. The region is characterized by the presence of a radiating dike swarm across the Queen Elizabeth Islands that seems to suggest the presence of a mantle plume beneath the Alpha Ridge. This province contains igneous rocks of both tholeiitic and alkaline composition. There are also a respectable number of sills and flood basalts in the province. The flood basalts in the Canadian Arctic Islands are similar to those of the Columbia River flood basalts in the Pacific Northwest of the United States. The Sverdrup Basin Magmatic Province covers an area of . Amerasian Basin The Amerasian Basin's most prominent feature is the Alpha Ridge – which is thought to be the location of the mantle plume that fed the HALIP. The ridge reaches a height of from the seafloor. Also in the region are a few basaltic dikes. The Amerasian