Seafloor Exploration and New Frontiers
Published:January 01, 2019
2019. "Seafloor Exploration and New Frontiers", From the Mountains to the Abyss: The California Borderland as an Archive of Southern California Geologic Evolution, Kathleen M. Marsaglia, Jon R. Schwalbach, Richard J. Behl
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A compilation of offshore and island geologic, marine acoustic, and seafloor sampling data for the Channel Islands National Park was used to construct geologic and potential marine benthic habitat maps of selected areas around various Channel Islands. For this investigation, we focused on three offshore areas around Santa Rosa Island (the north-central area west of Carrington Point, an area off and west of East Point, and an area off and west of South Point), and most of the shelf area around Santa Barbara Island. The maps represent the most detailed offshore mapping in the region to date, and they provide insights into the geology and potential benthic habitats in the area that can be used to manage marine biological and other resources.
The geology of the offshore areas is essentially an extension of the Tertiary geologic formations that have been mapped on the islands, but locally covered by deposits of Quaternary marine sediments. Structures in the north-central part of Santa Rosa Island and in the northeastern part of Santa Barbara Island appear to represent the most active regional tectonic processes, while the areas in the southern parts of Santa Barbara Island appear more passive, with few well-defined faults.
The first potential marine benthic habitat maps for the Channel Islands National Park are presented here, and they illustrate that diverse and favorable habitats exist. For example, the extensive areas of rugose, differentially eroded bedrock outcrops on the midshelf seafloor of the islands provide good habitats for demersal rockfish (Sebastes spp.), and rock outcrops in the nearshore areas provide hold-fasts for kelp, which can provide habitat for larval and young-of-the-year rockfish. Although true habitat is not well known in the areas studied, the potential habitat maps provide an effective management tool that can be used to protect and conserve the most promising probable habitats.