Yosemite National Park Y osemite is characterized by sky-piercing mountain peaks and plunging waterfalls The creation of these awe-inspiring features involved the collaboration of many dramatic and powerful forces of nature The basic building material of the Yosemite region is granite which is formed from molten rock that cools within the earth As it slowly cools to a solid large and interlocking crystals are formed which means that granite lacks the layering effect found in many other types of rock The same durability and consistency that makes granite a pre ferred stone for countertops and gravestones has allowed the Yosemite region to exhibit cliff faces that ascend straight up for thousands of feet Around the time that dinosaurs went extinct some 65 million years ago less resilient rock on the earth’s surface had eroded away exposing granite throughout the Yosemite area However the land was generally low and flat and it wasn’t until about 25 million years ago that actual mountains began to form This process was set in motion by a fault in Earth’s crust The incredibly massive chunk of crust on the western side of the break began tilting toward the west thus raising its eastern edge The result we see today is the Sierra Nevadas a mountain range extending 400 miles 643 km along California’s eastern border The range features steep eastern slopes and relatively gradual western slopes and is home to the region now called Yosemite While this tilting process was extremely slow and continues to this day even minor slants early on triggered another phase in the shaping of Yosemite Water that had once been scattered across the region in lakes and ponds began trickling to the west As time passed and the slopes increased streams began to flow with ever-increasing force Over millions of years this water flow carved canyons and gorges into the defiant granite Falling rocks are common along Yosemite’s mountain sides in 2012 the threat caused the park to close some cabins and campsites 10
No other national park in America can match Yosemite’s impressive waterways and waterfalls Tuolumne Falls pictured Two or three million years ago a drop in global temperatures and the still-increasing elevation of the Sierra Nevadas led to the formation of glaciers in the area Tons upon tons of snow compressed under its own weight creating massive sheets of ice in the mountains The glaciers typically formed at high altitudes and tremendous gravitational force then slowly pulled the icy behemoths down the mountain slopes As the glaciers descended loose or dislodged stone was dragged along further enhancing the glaciers earth-carving power expanding the erosion already caused by the rivers and streams Yet unlike water or wind that wear away only the most superficial layers of earth and create rounded edges and gradual slants the unstoppable masses of ice and stone gouged through solid rock leaving sheer cliffs of bare granite in their wake Yosemite Valley and its many waterfalls and smooth stone faces were created in this way Over thousands of years glaciers defined the landscape often 11
