Why did it take so long for upper plate extension to start? To find an explanation, we first explore the contributions of the two potential drivers of upper plate extension: roll-back, i.e., the retreat of the subducting slab through the mantle in the direction of the down-going plate;...
“Bison used what is called the Bering Land Bridge — a vast connection of land between Asia and North America — to cross from Asia into North America. The land bridge forms during ice ages, when much of the water on the planet becomes part of growing continental glaciers, making the sea...