GEL 25 Study Guide - Final Guide: Little Ice Age, Desert Pavement, Pacific Plate
Document Summary
Last 2. 6 million years have been filled with alternating glacial" and interglacial" phases. Yosemite landscape sculpted by grinding and quarrying of alpine glaciers. 20,000 years ago: lgm (last glacial maximum), pleistocene glacial phase. Valleys and high countries were embedded with rivers of glacial ice. Yosemite valley was filled in as a lake. As glaciers recede, meltwater flows across and modifies landscape. ~20,000 years ago continental ice sheets spread from greenland/canada to. American west was lush with flora and fauna. Crest of sierra nevada crowned in ice caps. Alpine glaciers are rivers of ice that flow downslope due to the gravitational pull of their own weight. Weight of ice causes mass to flow slowly downslope through valleys. Rocks tumble down flanks and accumulate at edges of glaciers. When glaciers merge, so does their debris forming elongate rows of rock debris called medial moraines.
