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National Parks represent the two different mountain ranges. ... National Park Lands in the Pacific Northwest. Parks in the Coastal Ranges contain ...
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Slide 3:Features in Parks at Subduction Zones
Accretionary Wedge Folded and thrust-faulted mountains and steep valleys Sedimentary layers (sandstone and shale) scraped off the ocean floor Basalt from the oceanic crust Volcanic Arc Steep, composite volcanoes Stratification of lava flows, ash, pumice, cinders, mudflows Andesite-to-rhyolite composition, with some basalt Explosive eruptions Ancient Volcanic Arc Cooled remains of granitic magma chambers Great climbing rock! Parks and Plates ©2005 Robert J. Lillie
Parks and Plates ©2005 Robert J. Lillie SUBDUCTION ZONES Active Subduction Zones Parks and Plates ©2005 Robert J. Lillie SUBDUCTION ZONES Ancient Subduction Zone Parks and Plates ©2005 Robert J. Lillie Parks and Plates ©2005 Robert J. Lillie Subduction of the Juan de Fuca Plate forms the Coastal Ranges and Cascade Volcanoes Parks and Plates ©2005 Robert J. Lillie Coastal Ranges Subduction of the Juan de Fuca Plate forms the Coastal Ranges and Cascade Volcanoes Mt. Olympus Parks and Plates ©2005 Robert J. Lillie COASTAL Mountain Range Olympic National Park, Washington Parks and Plates ©2005 Robert J. Lillie Coastal Ranges Cascade Volcanoes Subduction of the Juan de Fuca Plate forms the Coastal Ranges and Cascade Volcanoes Mount Rainier National Park, Washington Parks and Plates ©2005 Robert J. Lillie Parks and Plates, ©2005 Robert J. Lillie Subduction Produces Two Parallel Mountain Ranges in the Pacific Northwest Parks and Plates ©2005 Robert J. Lillie A plate capped with thin OCEANIC CRUST subducts beneath one capped with thick CONTINENTAL CRUST Parks and Plates ©2005 Robert J. Lillie Subducting Juan de Fuca Plate forms two parallel mountain ranges in the Pacific Northwest. Parks and Plates ©2005 Robert J. Lillie Oceanic sediment and basalt scraped off subducting plate, forming Coastal Mountains. Parks and Plates ©2005 Robert J. Lillie Subducting plate dehydrates, forming Cascade Volcanoes. Parks and Plates ©2005 Robert J. Lillie Subducting plate dehydrates, forming Cascade Volcanoes. Parks and Plates ©2005 Robert J. Lillie Puget Sound and the Willamette Valley are low-lying regions between the rising mountains. Parks and Plates ©2005 Robert J. Lillie National Parks represent the two different mountain ranges. Parks and Plates ©2005 Robert J. Lillie Coastal Ranges Juan de Fuca Plate Parks and Plates ©2005 Robert J. Lillie Parks in the Coastal Ranges contain materials that were manufactured in the sea, then scrapped off the subducting Juan de Fuca Plate and incorporated into the ACCRETIONARY WEDGE National Parks reveal the recycling nature of the Earth. Parks and Plates ©2005 Robert J. Lillie Olympic - Sized Recycling Machine! Time: 0 Parks and Plates ©2005 Robert J. Lillie A grain Mountains of sand is eroded from high in the Olympic . Parks and Plates ©2005 Robert J. Lillie Where it’s carried by the Hoh River. Parks and Plates ©2005 Robert J. Lillie To the Pacific Ocean, where it’s deposited in a layer of sand. Parks and Plates ©2005 Robert J. Lillie Time: 5 Million Years Parks and Plates ©2005 Robert J. Lillie Olympic - Sized Recycling Machine! Time: 20 Million Years Parks and Plates ©2005 Robert J. Lillie Olympic - Sized Recycling Machine! Only to be uplifted and exposed again in the Olympic Mountains. Parks and Plates ©2005 Robert J. Lillie Are the Olympic Mountains Getting Higher or Lower? Mt. Olympus 7,965’ Parks and Plates ©2005 Robert J. Lillie Parks and Plates ©2005 Robert J. Lillie Steady-State Subduction Olympic National Park, Washington Subduction leads to Uplift of Olympic Mountains Parks and Plates ©2005 Robert J. Lillie Steady-State Subduction Olympic National Park, Washington Parks and Plates ©2005 Robert J. Lillie Steady-State Subduction Olympic National Park, Washington Parks and Plates ©2005 Robert J. Lillie Steady-State Subduction Olympic National Park, Washington D D D’ D’ A cross section along line B-B’ reveals how the rocks of the park were manufactured in the sea, carried eastward by the Juan de Fuca Plate, then scraped off and incorporated into the ACCRETIONARY WEDGE. Parks and Plates ©2005 Robert J. Lillie Accretionary Wedge Geology of Olympic National Park, Washington Olympic National Park, Washington The CORE AREA is younger rocks surrounded by older. Parks and Plates ©2005 Robert J. Lillie Younger sedimentary layers are carried eastward and downward on top of the subducting Juan de Fuca Plate. Olympic National Park, Washington The CORE AREA is younger rocks surrounded by older. Parks and Plates ©2005 Robert J. Lillie Older basalt of the Crescent Terrane are thrust over the younger Core Area rocks. Olympic National Park, Washington The CORE AREA is younger rocks surrounded by older. Parks and Plates ©2005 Robert J. Lillie Uplift and Erosion has exposed the younger Core Area rocks within the arc of the Crescent Terrane. Parks and Plates ©2005 Robert J. Lillie The CORE AREA is sedimentary layers uplifted from the ocean floor. Much of the rock has been metamorphosed and tilted. Geology of Olympic National Park, Washington Mt. Olympus Parks and Plates ©2005 Robert J. Lillie CORE AREA Olympic National Park Parks and Plates ©2005 Robert J. Lillie Olympic National Park, Washington Uplifted and Tilted Turbidite (Sandstone and Shale) Layers Parks and Plates ©2005 Robert J. Lillie CORE AREA Olympic National Park Vertical Layering Parks and Plates ©2005 Robert J. Lillie Robert J. Lillie Uplifted and Tilted Turbidite Layers Layers Before Tilting Olympic National Park, Washington CORE AREA Olympic National Park Parks and Plates, ©2005 Robert J. Lillie Parks and Plates ©2005 Robert J. Lillie Metamorphic Rocks CORE AREA Olympic National Park Parks and Plates ©2005 Robert J. Lillie The CRESCENT TERRANE is basalt erupted on the seafloor and oceanic islands. It was added (accreted) to North America during plate convergence. Geology of Olympic National Park, Washington The Needles Parks and Plates ©2005 Robert J. Lillie CRESCENT TERRANE Olympic National Park Oceanic Basalt Why are the lava flow rocks in Olympic National Park so dark and heavy? Parks and Plates ©2005 Robert J. Lillie Hurricane Ridge Road Parks and Plates ©2005 Robert J. Lillie Olympic National Park Pillow Basalt Formation of Pillow Basalt Parks and Plates, ©2005 Robert J. Lillie Oceanic Crust Formation of Pillow Basalt Parks and Plates, ©2005 Robert J. Lillie Oceanic Crust Lava Erupts into Cold Ocean Water Parks and Plates ©2005 Robert J. Lillie GLACIAL DEPOSITS cover older sedimentary layers in the northern parts of the park. Spectacular angular unconformities result. Geology of Olympic National Park, Washington ANGULAR UNCONFORMITY Olympic National Park, Washington Parks and Plates, ©2005 Robert J. Lillie Parks and Plates ©2005 Robert J. Lillie STREAM DEPOSITS cover older sedimentary layers in the western part of the park. Geology of Olympic National Park, Washington Parks and Plates ©2005 Robert J. Lillie Cross Section E-E’ reveals the tectonic positions of Redwood National and State Parks, Oregon Caves National Monument, and Lassen Volcanic National Park. Parks and Plates ©2005 Robert J. Lillie E E’ Parks and Plates ©2005 Robert J. Lillie E E’ Parks and Plates ©2005 Robert J. Lillie Redwood National and State Parks, California Deformed and metamorphosed sedimentary rocks Parks and Plates ©2005 Robert J. Lillie Redwood National and State Parks, California Mouth of the Klamath River
