![]() Sand absorbs and stores a large part of the annual rainfall. Currents, tides and wave action dredge sand from the ocean floor and deposit it on the beaches where the wind takes over. Strong ocean currents flowing north in winter and south in summer hold sediment from rivers near the shore. Seasonal changes in wind direction reshape dune sculptures and ridges. These winds blow from the south and southwest, moving large amounts of sand. In winter, winds vary more however, they can exceed 100 miles per hour during intense winter storms. Mountain barriers near the coast deflect wind currents, sculpting the sand into many different shapes. Summer winds blow steadily from the north and northwest at 12 to 16 miles per hour. Wind and water are the two strongest forces shaping dune formation. Look for quicksand in low, unvegetated areas between the dunes. With the upward pressure of water, the sand grains become more saturated and may float, resulting in quicksand. In the wet winter, the rising water table creates marshy areas with standing water several feet deep. Where winds have removed sand down to the water table, plants have flourished. These winds blow from the south and southwest moving large amounts of sand. In winter, winds are generally lighter however, they can exceed 100 miles per hour during intense winter storms. Mountain barriers near the coast deflect wind currents, sculpting the sand info many different shapes. ![]() Summer winds blow steadily from the north and northwest at 12-16 miles per hour. Winds are a major influence in dune formation. This low rock surface stretches 56 miles from Heceta Head to Cape Arago and contrasts with steep headlands found on most of the Oregon coastline, which prevent inland movement of sand. This area of dune development rests on a gently sloping terrace of solid marine sandstone called the Coos Bay Dune Sheet. Tides, wave action and strong coastal winds moved sand up to 2.5 miles inland for thousands of years. The present shoreline stabilized 6,000 years ago. As rock was moved downstream by rivers, it tumbled and abraded itself into sand. The sand in the Oregon Dunes is from the Coast Mountain Range, which is sedimentary rock that was uplifted 12 million years ago. The sand dunes were formed by wind, water and time. Managed by the USDA Forest Service, this is the only part of the Oregon coast covered by extensive sand dunes. Desert-like landscapes, lakes, rivers, ocean and forest blend, creating diverse ecosystems of plants and animals. Bonn adds that getting out of the quicksand at this point is tough the force required to pull out a foot equals that needed to lift a medium-sized car.The Oregon Dunes are like no other dunes in the world. According to measurements taken from the bead experiments, increasing the physical stress on the particles by just 1% can cause their flow speed to increase by a factor of a million, creating a downward pull. "An extremely small variation in stress can cause the complete collapse of this material," he says. Bonn likens the disturbance to the toppling of a stack of neatly arranged oranges. The team shook the system, and watched as this action partially submerged the beads.Īn object that falls into quicksand can cause the sand particles supported by water to loose their stability and flow downwards in a liquid fashion. Walking on waterīonn and his colleagues then placed aluminium beads, which had the same density as an average human, on top of their homemade quicksand. Once they had determined the proportions of fine sand, salt water and clay in the quicksand, they mixed up larger batches of the same. The warnings piqued his curiosity and inspired him to take a sample back to the Netherlands, where he and his colleagues analysed its composition. Bonn also heard cautionary tales from local shepherds. The researcher from the University of Amsterdam saw signs alerting visitors to the danger of this grainy soil near the Namak Lake, located in the north of the country. Quicksand in the lab began on a trip to Iran. Dutch courageīut scientists have not tired of disproving the myth. "The Hollywood version is just incorrect," says Thomas Zimmie, an expert in soil mechanics at the Rensselaer Polytechnic Institute in Troy, New York. The probability that a person will be completely sucked into the sand, on the other hand, is nil. “The real danger of quicksand is that you can get stuck in it when the high tides come up.”ĭaniel Bonn, University of Amsterdam, The Netherlands
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