page_title: Milbanke Sound Group
section_title: Volcanoes
hierarchical_section_title: Milbanke Sound Group / Geology / Volcanoes
caption_attribution_description: English: Satellite image of Kitasu Hill.
context_page_description: The Milbanke Sound Group, also called the Milbanke Sound Cones, is an enigmatic group of five small basaltic volcanoes in the Kitimat Ranges of the Coast Mountains in British Columbia, Canada. Named for Milbanke Sound, this volcanic group straddles on at least four small islands, including Swindle, Price, Lady Douglas and Lake Island. Not much is known about this group of volcanoes and they remain undated. However, they all likely formed in the past 10,000 years after the last glacial period as evidenced by a small amount of erosion. The age of the most recent volcanic activity is also unknown. Most of the Milbanke Sound Cones are covered by mature forest. Kitasu Hill and Helmet Peak are the only two cones that are officially named.
  This group of volcanoes is unlike many other volcanic groups in Canada as it resides on islands instead of on the mainland. The volcanoes form a northwest-southeast trend along the British Columbia Coast. To the west the Milbanke Sound Group is bounded by the Pacific Ocean and elsewhere it is surrounded by adjacent islands that form an archipelago.
context_section_description: Just south of Kitasu Bay on the southwestern shore of Swindle Island, Kitasu Hill rises with an elevation of 250 m (820 ft) and a topographic prominence of 230 m (750 ft). This is a small symmetrical monogenetic cinder cone and the best preserved volcano associated with the Milbanke Sound Group. It is the northernmost and most prominent volcano of the Milbanke Sound Cones with a circular volcanic crater at its summit. The volcano produced basaltic lava flows that extend to the north. Subaerial tephra and volcanic bombs are the main volcanics comprising the volcano. These volcanics surround eroded remains of the basalt lava flows and are composed of the mineral olivine. Kitasu Hill rests on till that overlies glacially scoured bedrock.
  Near the northeastern shore of Price Island, a small eroded monogenetic cinder cone composed of basalt is covered by mature forest. It has an elevation of 40 m (130 ft) and is the source of a basaltic lava flow. This lava flow extends down to the northeastern shoreline of Price Island where it covers beach gravel.
  Helmet Peak on the northern end of Lake Island just off the southwestern side of the Don Peninsula is a steep-sided monogenetic cinder cone. It is composed of welded volcanic blocks and basaltic feeder dikes. With an elevation of 335 m (1,099 ft), Helmet Peak is the highest volcano in the Milbanke Sound Group. During its eruption, basaltic tuff breccia was sent throughout the surrounding landscape that deposited on glaciated granitic rock and unconsolidated beach gravel near the volcano. This basaltic tuff breccia covers parts of Lake Island and nearby Lady Douglas Island. Blocks of basement granodiorite, some up to 2 m (6.6 ft) wide, are randomly suspended within the breccia. Basalt on Lake Island is characterized by abundant 0.5 cm (0.20 in) to 1 cm (0.39 in) labradorite and clinopyroxene phenocrysts.
  At the southern end of the Milbanke Sound Group, a small monogenetic cinder cone with an elevation of 50 m (160 ft) resides on Dufferin Island. It sent basaltic lava flows to the north where they reached the island's shoreline to cover beach gravel. Since its formation, the cinder cone has been eroded and covered by forest. Finngal Island, south of Dufferin Island, contains one or more basaltic lava flows that form well-preserved columnar jointing. Like other volcanic deposits in the Milbanke Sound Group, little is known about these lava flows.
caption: Satellite image of Kitasu Hill and its circular volcanic crater
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