Waimea Canyon
From GeoClasses
Contents |
Initial Summary
The Waimea Canyon is located on the Kauai Island in Hawaii. Not many people know that Hawaii has a canyon, so I decided to do this particular landform project because not only will I learn about this most interesting canyon, but my classmates and future landforms students will learn something new as well. The Waimea Canyon is the largest canyon in the Pacific. The Waimea Canyon is 3,600 feet deep and 10 miles long. In order to understand how the Waimea Canyon is formed, one must understand the geologic history of Waimea Canyon. I am going to explore the geologic history so that my classmates and I will understand why the Waimea Canyon has the features it has. Also I really want to understand the relationship between Makaweli Graben and the Waimea Canyon. I would love to learn about the mass wasting of the land. I want to know more about the soil color and why it's red. Erosion of the Waimea Canyon is a interesting topic to explore. It is very interesting to me because I have not been there and this canyon is so beautiful to me. Most importantly, I will have learned a great deal studying this landform.
<http://en.wikipedia.org/wiki/Image:Waimea_Picture.jpg>
Geologic History of Waimea Canyon
According to West Kauai, "the canyon has a unique geologic history—it was formed not only by the steady process of erosion, but also by a catastrophic collapse of the volcano that created Kauai.
Like the other Hawaiian islands, Kauai is the top of an enormous volcano rising from the ocean floor. With lava flows dated to about 5 million years ago, Kauai is the oldest of the large Hawaiian islands. Roughly 4 million years ago, while Kauai was still erupting almost continuously, a portion of the island collapsed. This collapse formed a depression, which then filled with lava flows.
In the time since, rainwater from the slopes of Mount Waialeale (one of the wettest spots on Earth, with 450 inches of rain a year) have eroded Waimea Canyon along one edge of the collapse. The cliffs on the west side of the canyon are composed of thin lava flows that ran down the surface of the Kauai volcano. On the other side of the canyon, the cliff walls are built from thick lava flows that pooled in the depression. Over time, the exposed basalt (a type of rock formed from lava) has weathered from its original black to brilliant red,"(Para1-3 West Kauai).
"The Canyon lies on a normal fault zone separating the two distinct lava flows. Along this ancient slip surface the Makaweli trough (also called a graben) collapsed downwards creating a huge scarp which is the cliff face of the Napali member lavas.(ref. 2) So, looking North, up the Waimea Canyon, (photo left) one can see the striking difference between the two flows: the Olokele and Makaweli Members, on the East (right) side, and the Napali member on the West (left) side," according to Jeani Steverson.
<http://www.hawaiiweb.com/kauai/html/sites/waimea_canyon.html>
Why Is the Soil of Waimea Canyon Red?
"The red color in soil usually indicates a high amount of iron, in the form of iron oxide, that coats the particles of the soil. The iron oxide can be inherited from the parent material or can form as a result of intense weathering over a long period of time," states What Makes Soil Red (para 1 What Makes Soil Red). This "weathering" refers to the weathering of basalt rocks. The basalt rocks came from the volcanic eruption that helped form the canyon. Over the years the basalt became oxidized by water and thus became red. This is why the soil is red.
<http://www.markphillips.com/photography/2004-11-27.Kauai.WaimeaCanyon/DSC_3782.html>
Weathering and Mass Wasting of the Canyon
"The headwaters of the the many streams and waterfalls on Kaua'i are fed by the contunuous rainfall on Mt Wai'ali'ali (5,080 ft.above sealevel) and nearby Mt. Kawaikini (5,170 ft.), which gets an average rainfall of 450 inches per year. It is understandable that this area is famous for being the wettest spot on earth! It is also easy to see why erosion and mass wasting occurs continually due to the huge amout of water flows. Alternating layers of lava flow and sedment reflect periods of growth followed by periods of weathering and erosion.This landscape was carved through tholeitic an dpostshield alka lic levels of the Waimea Canyon Basalt. Further erosion by wind and incised meandring of Waimea River and its many contributors streams and waterfalls adds to weathering and mass wasting," states The Waimea Canyon (Para 4 The Waimea Canyon).
Erosion Of The Rock Features
"Water is the most effective process in erosion. This cliff has been deeply metamorphosed and weakened by the constant rainfall, leaving only the strongest rock to survive. The canyon because of its labyrinth of structures, and daily heating and cooling creates wind drafts that blow up and down and around the canyon. This causes loose sediment to break off in chunks leaving the jagged edges seen in this picture. Lava flows along the sides of the waterfall stream are rubbed smooth of loose sediment by water flowing past them. Rain and winderosion create interesting jagged shapes in this Waimea Canyon basalt. Pools of water at a shelf below a waterfall exhibits the effects of water erosion. The rounded and smooth rocks where falling water has shoved any rough edges that may have been its pathway," according to Steverson(para 5 The Waimea Canyon).
Makaweli Graben
"The canyon to the east rim of the Olokele graben, a post shield-building lava of 3.95 m.y. At the top is the Alakai Plateau (Swamp) which is the result of the downward collapse of the Olokele and part of the Makaweli graben. The Makaweli post shild graben (4.2-3.9 m.y.) is a trough-like sturcture that dropped between two faults, and then was partially filled with lava when the volcano resumed its activity. (ref.6, ref. 9) Graben is a German term which mean "the grave". The graben is bordered by faults that are parallel. This graben is a result of land that is being pushed down to form a valley. The reason for the flat topped areas of these two members is best ecplained in an article on the Yale University website: 'Lavas of the Olokele and Makaweli members flowed from the east or northeast, and ponded up against this big cliff, forming the thick, flat-lying flows of the east side of the canyon.' (ref. 2)," concludes Steverson (para 2 the Waimea Canyon).
References
Duncan, Brian. Waimea_Picture. 23 Nov 2006. 27 Jun 2008<http://en.wikipedia.org/wiki/Image:Waimea_Picture.jpg>
Phillips, MArk."2004-11-27 Kauai Waimea Canyon" Mark's Pages. 27 Nov 2004. 29 Jun 2008. <http://www.markphillips.com/photography/2004-11-27.Kauai.WaimeaCanyon/DSC_3782.html>
Simmon, Robert. Waimea Canyon, Kaua’I. NASA.<http://veimages.gsfc.nasa.gov//16671/Kaua._ etm_2000361.jpg>
Stein, Robert, III. Waimea Canyon Panorama. 5 Nov 2006. 27 Jun 2008.<http://en.wikipedia.org/wiki/Image: Waimea_ Canyon_ Panorama.jpg >
Stevenson,Jeani. The Waimea Canyon. 2003. 27 Jun 2008 <http://www2.hawaii.edu/~jeanstev/Kauai/waimea_canyon.html>
“West Kauai.” Hawiiweb.com. 2003. 27 Jun 2008 <http://www.hawaiiweb.com/kauai/html/sites/waimea_canyon.html>
What Makes A Soil Red?. 10 Sep 1997. 29 Jun 2008. <http://soil.gsfc.nasa.gov/pit/redsoil.htm>
