These are also known as " stones ", and can also break the glass when the glass is heated, as they create thermal anomalies.
12.
First a thermal anomaly developed in the mantle in the earliest stages of rifting, causing the rise of the asthenosphere, and the thinning of the subcrustal continental lithosphere.
13.
Since then, thermal anomalies ( hot spots ) and gas emissions ( including hydrogen sulfide ) have occurred especially on the summit plateau and indicate that Adams is extinct.
14.
The westward movement of the plates and the ridge above the plume and the strong thermal anomaly of the latter caused this old spreading center to starve 15 million years ago and lead to the formation of a new one in the area of today's peninsulas Skagi and Sn�fellsnes; in the latter there is still some activity in the form of the Sn�fellsj�kull volcano.
