Australia: James Cook University’s (JCU) Robin Beaman produced a new map of Australia’s Coral Sea region that details the reefs, mountains and canyons that exist under the sea.
A major finding that the map details is the large number of underwater canyons in the area as well as 14 mountains, or seamounts rising at least 1000 metres from the sea floor. “One seamount, the Fraser Seamount, is 4060 metres high, nearly twice the height of Mt Kosciuszko, Australia’s highest mountain,” Dr Beaman said. “Surprisingly half of these seamounts have no identifying name which would be very unusual if they were found on dry land.”
The large numbers of submarine canyons were found wherever the seafloor gradient exceeded just one degree in slope.
“The largest canyon in the Coral Sea, the Bligh Canyon, drains sediment from a huge area of the continental shelf extending from Cape York, the Torres Strait, and southern Papua New Guinea,” Dr Beaman said. “This canyon is more than 200 km long, nearly 10 km wide and cuts about 300 metres into the seafloor.”
Using a combination of the latest satellite imagery to trace the shallow-water features, such as coral reefs and cays, and then sonar to map and trace the deeper-water features, the new map took more than a year to create. It traced the boundaries of undersea, or geomorphic features and they can also be seen in the new high-resolution depth model for the Coral Sea, called the gbr100 grid.
“Geomorphology describes the geological shape of the Earth and so geomorphic maps of the seafloor are a useful way to identify the important marine habitats,” Dr Beaman said.
The new digital map was generated by hand digitizing polygons for individual geomorphic features within a geographic information system, and then adding the feature names to the polygon database, where names were available.
The release of the Geomorphic Features map in a variety of formats coincides with the public consultation period for a Commonwealth marine reserve proposal for the Coral Sea ).
Dr Beaman’s research was supported by a USD 150,000 Queensland Government Smart Futures Fellowship, and matching grants from the Reef and Rainforest Research Centre and James Cook University.
One can download full-colour high-res images of the Coral Sea, a ‘flyover’ video, and other content at
https://www.deepreef.org/bathymetry/65-3dgbr-bathy.html or https://e-atlas.org.au/content/gbr-jcu-bathymetry-gbr100
Source: Science Alert
