File(s) under permanent embargo
Submarine geology and geomorphology of active Sub-Antarctic volcanoes: Heard and McDonald Islands
In early 2016, we conducted marine geophysical and geologic surveys around HIMI aboard RV Investigator (IN2016_V01). Results show that volcanic and sedimentary features prominently trend east-west, likely a result of erosion by the eastward flowing Antarctic Circumpolar Current and tidal currents. However, spatial patterns of submarine volcanism and sediment distribution differ substantially between the islands. >70 sea knolls surround McDonald Island suggesting substantial submarine volcanism. Geophysical data reveals hard volcanic seafloor around McDonald Island, whereas Heard Island is characterised by sedimentary sequences tens of meters or more thick and iceberg scours - indicative of glacial processes. Differences in submarine geomorphology are likely due to the active glaciation of Heard Island and differing rock types (Heard: alkali basalt, McDonald: phonolite), and dominant products (clastics vs. lava). Variations may also reflect different magmatic plumbing systems beneath the two active volcanoes (Heard produces larger volumes of more focused lava, whilst McDonald extrudes smaller volumes of more evolved lavas from multiple vents across the edifice).
Using geophysical data, corroborated with new and existing geologic data, we present the first geomorphic map revealing the processes that shape the submarine environment around HIMI.
History
Publication title
American Geophysical Union Fall Meeting abstractsPagination
V43F-08Department/School
Institute for Marine and Antarctic StudiesEvent title
American Geophysical Union Fall MeetingEvent Venue
San Francicso, USADate of Event (Start Date)
2016-12-12Date of Event (End Date)
2016-12-16Repository Status
- Restricted