Red and White Bands

The Needles are a series of spires located to the southwest of Squaw Flat campground that surround the Chesler Park area of the Needles District. They are formed out of a resistant red and white sandstone layer called Cedar Mesa Sandstone which makes up most of the rock features in the Needles District. This 245 to 286 million year old layer was once a dune field on the eastern edge of a shallow sea that covered what is California, Nevada and western Utah today. Sand was blown in from this direction and formed the white bands in the Cedar Mesa Sandstone. The red bands came from sediment carried down by streams from a mountainous area near where Grand Junction is today. These layers of sand were laid down on top of each other and created the distinctive rocks seen today.

How Needles Form

About ten million years ago, the Colorado Plateau was pushed up thousands of feet and rivers, such as the Colorado and the Green, cut down and carved deep canyons. Water, the primary force of erosion, eats away or weathers rock by attacking the cement holding the sand grains together. Moreover, during storms, rushing water knocks loose sand and rocks as it flows down washes causing additional erosion. The water naturally acts faster on areas of weakness within the rock, such as fractures and cracks. The Needles occur in an area with many fractures called joints.

The joints were formed in two different manners. The first is the Monument uplift, located just to the south of the Needles district and west of the Abajo Mountains. The ground was lifted higher than the surrounding area and caused the brittle rock layers above, such as the Cedar Mesa Sandstone, to crack as they were bent upward. This formed a set of joints in a northeast-southwest direction. A thick salt layer underneath the Needles district, known as the Paradox Formation, is the second cause of joint formation. The salt is flowing slowly toward the Colorado River and dragging the overlying layers with it. As the upper layers became stretched, they also fractured into joints. This action created a set of joints running northeast-southwest. In the Needles area, these two joint sets meet and form square blocks of rock between the joints. As water widened the joints, the squares were sculpted into pillars and spires that are today the Needles of Canyonlands.

Written by Rebecca Kunz