Hills emerge as glaciers retreat

摘要

Most drumlins - small, rounded hills -were formed under melting Pleistocene ice sheets. But the recent retreat of the Mulajdkull glacier in Hofsjokull, Iceland, has uncovered the only known activerndrumlin field created during modern times.rnMark Johnson of the University of Gothenburg, Sweden and his colleagues identified more than 50 drumlins in this field and studied their sediment layers. Some theories posit that drumlins are carved out from the sediment by a rush of glacial meltwater.