Because compression causes shortening, but sometimes rapid subduction cause vigorous circulation in the mantle (for rather obvious reasons) and that can result in back arc spreading and volcanism - which is what we observe in the Mediterranean. Ad hominem, and plan and simply rude. Ad hominem, poisoning the well, and an outright lie. Carey was actually talking about Diapirs - structures that rise up to 100km above their base, and pierce through the crustal lithosphere. You are talking about Mantle structures that reach the crustal lithosphere and spread out beneath it - not the same thing by a long shot. I'm familiar with the etimology of the word, one of the reasons for my assertion that you are using it wrongly. For one thing, it was your assertions about expansion that I was referring to as wrong. The entire Mediterranean basin is closing, east, central, and west, all of your sources that you have cited (so far) support this assertion, along with the assertion that any extension that is occuring in the basin is being driven by mantle convection, which in turn is being driven by the subduction occuring as the African plate collides with the European plate. It seems baseless to you because you do not understand it. I'm not going to explain it to you any more than I already have, because I choose not to get involved in that particular discussion with you at this time, because you have already dragged this thread far off topic with your toy model. There are extensional tectonics at work, as a result of the ongoing subduction of the African plate under the European one, yes. I believe that Rocco's work supports my assertions, yes, however you have to first understand what my assertions are, and have been in full to understand why, and I do not believe that you have fully understood my assertions. For example - do you recall me stating that the area where that diagram pertains to has in the past experience a mixture of compressive and extensional tectonics, but for the last 5 million years had been in a predominantly compressive regime? I disagree with that authors assessment, I think that based on the work of the likes of Facenna and Becker that the author of that diagram is very much mistaken. I am unconvinced that you're using the term 'straw man' correctly.