Massive Ancient Tectonic Slab Found Below the Indian Ocean

EOS ^ | 3/8/2016 | Cody Sullivan

[JimSEA]

Seismic wave velocity structure in deep Earth revealed through seismic tomography. Seismic wave velocity structure in the deep Earth revealed through seismic tomography. Earthquakes generate seismic energy near their epicenters (yellow markers), and the energy is recorded at seismic stations around the world (red markers). Seismic waves (depicted as yellow rays emanating from an earthquake beneath Spain) are disrupted as they travel through fast (blue) and slow (red) structures in the Earth.

A team of researchers recently discovered an ancient relic hidden within Earth: a tectonic plate resting beneath the southern Indian Ocean. Scientists have found other tectonic plates that sank below Eurasia and North America, but here Simmons et al. describe the unique structure of this newly discovered slab, which they named the Southeast Indian Slab (SEIS). The slab has at least one feature scientists have rarely seen before: It maintains its slab-like structure all the way from the upper mantle near Earth’s crust down to the region where the mantle meets the planet’s superheated core.

Once this tectonic slab was identified, the team looked at the region’s tectonic history over millions of years to determine where and when this plate was on the surface. They determined that the slab was once along the eastern portion of the early supercontinent of Gondwana. Then, sometime during the Triassic or Jurassic period, which stretched from 250 million years ago to 145 million years ago, the slab plunged underneath another plate. They further concluded that the subduction, or the sinking of the Southeast Indian Slab beneath another plate, terminated around 130 to 140 million years ago in the Mesozoic era, around the same time that the tectonic plates under eastern Gondwana began to separate and split up the continent.

[JimSEA]

Go to the source article for an illustration of how this plate has gone into the mantle without losing all of its heat. It's now adjacent to the outer core and hasn't yet heated to the point of the surrounding mantle.

[CARTOUCHE]

So what do you surmise caused the slab to lodge beneath the other? Fascinating stuff. Thanks for sharing.

[JimSEA]

Just a guess, the temperature differential of the two slabs has prevented normal heat exchanges with the mantle.

[fieldmarshaldj]

*ping in case you hadn’t seen it*

[Arthur McGowan]

Stop Anthropogenic Continental Drift!

[43north]

I heard they found owebama’s birth certificate down there too...

[Rurudyne]

This slab is owed reparations from land masses that pushed it down.

[Hotlanta Mike]

I blame it on made made climate change...