Wanting just like the Eye of Sauron from the Lord of the Rings trilogy, an historic undersea volcano was slowly revealed by multibeam sonar 3,100 meters (10,170 ft) beneath our vessel, 280 kilometers (174 miles) southeast of Christmas Island.
Beforehand unknown and unimagined, this volcano emerged from our screens as an enormous oval-shaped melancholy referred to as a caldera, 6.2 km by 4.8 km throughout. It’s surrounded by a 300-m-high rim (resembling Sauron’s eyelids), and has a 300-m-high cone-shaped peak at its heart (the ‘pupil’).
Above: Sonar picture of the ‘Eye of Sauron’ volcano and close by seamounts on the ocean mattress south-west of Christmas Island.
A caldera is shaped when a volcano collapses. The molten magma on the base of the volcano shifts upwards, leaving empty chambers. The skinny strong crust on the floor of the dome then collapses, creating a big crater-like construction. Typically, a small new peak then begins to kind within the heart because the volcano continues spewing magma.
One well-known caldera is the one at Krakatoa in Indonesia, which exploded in 1883, killing tens of 1000’s of individuals and leaving solely bits of the mountain rim seen above the waves. By 1927, a small volcano, Anak Krakatoa (“baby of Krakatoa”), had grown in its heart.
In distinction, we could not even pay attention to volcanic eruptions once they occur deep beneath the ocean. One of many few tell-tale indicators is the presence of rafts of sunshine pumice stone floating on the ocean floor after being blown out of a submarine volcano. Ultimately, this pumice stone turns into waterlogged and sinks to the ocean ground.
Our volcanic ‘eye’ was not alone. Additional mapping to the south revealed a smaller sea mountain lined in quite a few volcanic cones, and additional nonetheless to the south was a bigger, flat-topped seamount.
Though creator J.R.R. Tolkien’s data of mountain geology wasn’t excellent, our names are splendidly applicable given the jagged nature of the primary and the pumice-covered floor of the second.
The Eye of Sauron, Barad-dûr, and Ered Lithui are a part of the Karma cluster of seamounts which were beforehand estimated by geologists to be greater than 100 million years previous, and which shaped subsequent to an historic sea ridge from a time when Australia was located a lot additional south, close to Antarctica.
The flat summit of Ered Lithui was shaped by wave erosion when the seamount protruded above the ocean floor, earlier than the heavy seamount slowly sank again down into the gentle ocean seafloor. The summit of Ered Lithui is now 2.6 km beneath sea degree.
However right here is the geological conundrum. Our caldera appears to be like surprisingly recent for a construction that needs to be greater than 100 million years previous. Ered Lithui has nearly 100 m of sand and dirt layers draped over its summit, shaped by sinking lifeless organisms over hundreds of thousands of years.
This sedimentation charge would have partially smothered the caldera. As a substitute it’s doable that volcanoes have continued to sprout or new ones shaped lengthy after the unique basis. Our stressed Earth isn’t nonetheless.
However life adapts to those geological modifications, and Ered Lithui is now lined in seafloor animals. Brittle-stars, sea-stars, crabs, and worms burrow into or skate over the sandy floor. Erect black corals, fan-corals, sea-whips, sponges, and barnacles develop on uncovered rocks. Gelatinous cusk-eels prowl round rock gullies and boulders. Batfish lie in await unsuspecting prey.
Our mission is to map the seafloor and survey sea life from these historic and secluded seascapes. The Australian authorities not too long ago introduced plans to create two huge marine parks throughout the areas. Our expedition will provide scientific information that can assist Parks Australia to handle these areas into the long run.
Scientists from museums, universities, CSIRO, and Bush Blitz round Australia are taking part within the voyage. We’re near finishing half one among our journey to the Christmas Island area. Half two of our journey to the Cocos (Keeling) Island area shall be scheduled within the subsequent 12 months or so.
Little doubt many animals that we discover right here shall be new to science and our first information of their existence shall be from this area. We count on many extra stunning discoveries.