lithospheric drip?

I have never ever heard of lithospheric drip... and then I got an article emailed to me.
here it is.

I'll also post some of the text.
"While studying the extension of the region, geologist John West of ASU was surprised to find that something unusual existed beneath this area's surface.

West and colleagues found that portions of the lithosphere--the crust and uppermost mantle of the Earth--had sunk into the more fluid upper mantle beneath the Great Basin and formed a large cylindrical blob of cold material far below the surface of central Nevada.

It was an extremely unexpected finding in a location that showed no corresponding changes in surface topography or volcanic activity, West says.

West compared his unusual results of the area with tomography models--CAT scans of the inside of Earth--done by geologist Jeff Roth, also of ASU. West and Roth are graduate students; working with their advisor, Matthew Fouch, the team concluded that they had found a lithospheric drip."

I found this very very interesting. Mostly because I have never heard of lithospheric drip before. So I am now going to go find their article and do some reading... ok well add it to my reading list. I am totally intrigued by this!