Upside-down world under North Sea: 7-million-year-old structures defy the rules of the ocean
The North Sea has strange structures under it at a depth of 300 feet. They were born seven million years ago and go against the known rules of the ocean. After years of exploration, scientists finally know why they are topsy-turvy.
North Sea hiding mysterious mounds
The North Sea, despite being extensively drilled for oil and hosting the largest number of offshore wind farms, is still a mystery to scientists. Under the sea floor lie enormous mounds of sand that stretch for several kilometres. Scientists gathered seismic data and rock samples to find out what was going on.
Something strange was discovered in the North Sea
They found that a rare geological process was at work under the North Sea. The older layers of sand are lying on top of younger ones, creating an upside-down environment. Two geologists think they have an answer for the mysterious structures. Professor Mads Huuse of The University of Manchester said dense sand has sunk into lighter sediments that floated to the top of the sand.
The structures were formed 7-4 million years ago
The mounds are 660 feet deep, and some of the "sinkites and floatites" are the largest of their type ever seen, Huuse and co-author Jan Rudjord of Aker BP said. They are dated to the Late Miocene and Pliocene epochs, making them 7-4 million years old. Scientists have known about these mounds for years, but have never understood what led to the strange anomaly.
Ooze discovered under the mounds
Three things are at play here, according to the two researchers. First is a deposit of rigid but light material, comprising mostly small marine fossils called bio-silicious ooze. They were formed when microscopic marine creatures bloomed as a result of the North Atlantic sending nutritious water upwards into the North Sea.
Earthquake or pressure change caused anomaly in North Sea
Then there is denser sand that can liquify and flow through at least some of the older rock. The last ingredient is what triggered the sand t flow downwards, which was likely an event like as earthquake. Sharp changes in underground pressure could have also caused the sand to behave in this manner.
Sand moved like a fluid under the sea
Normally, the older sand gets buried deeper than the new sand, shaping geological history. But in this case, the new sand went under the older sand, which is strange. The sand behaved like a fluid and travelled through the openings and settled underneath the rigid ooze.
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