Controversies in Understanding the Formation of the Grand Canyon: Evidence for a Lava Dam Breach Modern attempts to explain ancient natural wonders are often fraught with controversies. The Grand Canyon, one of the seven natural wonders of the world, is no exception. There are a number of conflicting theories as to how the canyon was formed. The most commonly believed one is that the Colorado River slowly downcut into grandiose canyon ways after millions of years of erosions, while the Colorado Plateau slowly rose above the rest of the landscape. However, there are a number of problems with this theory mainly that it does not account for the differences in the ages of the eastern and western ends of the canyon. Another, alternative theory is that there was a violent dam breach when a lava dam was destroyed, causing a massive flood that gushed into the canyon, tearing into the soft limestone and forever changing the course of the Colorado River. Based on geological evidence, this proves one of the more understandable theories for the canyon's development.

The Grand Canyon is one of the most interesting geological wonders of the world, and it is right here in our backyard. It stretches over 277 miles across the northern portion of Arizona, in the middle of the Southwest desert of the United States (Meek & Douglass, 2001). It is not a single river, but rather a very extensive system of rivers and tributary canyons that extend deep under ground and across hundreds of square miles of the northern Arizona desert. The canyon boasts complex geological features that some say date as far back as the Precambrian era. In fact, the research states that "the canyon offers one of the best geological cross sections in the world, with nearly 30 distinct layers found from the bottom to the top; the mesas, buttes, colorful slopes, and spires illustrate the geological story of the great American Southwest" (Missler, 2011). It is definitely one of the most beautiful and awe-inspiring natural features of the Northern Hemisphere.

Still, there are some controversies revolving around what exactly caused the original formation of the canyon, with conflicting theories all holding some weight within the scientific community today. One of the most commonly told theories, and the one favored by the park rangers themselves, is that the 130,000 square miles of the Colorado Plateau "began to rise up 50-70 million years ago, causing the existing Colorado River to downcut," and thus carve out the magnificent wonder that makes up the sprawling canyons today (Missler, 2011). This theory states that the formation of the canyon was a slow and gradual one, occurring through erosion as the Colorado River slowly changed course while the Colorado Plateau continued to rise above the rest of the terrain in the region. Ultimately, "the higher the plateau rose, pushed upward by magma from deep in the earth, the more powerful the erosional forces of the river proved to be" (Missler, 2011). Again, this is the theory most commonly accepted by park enthusiasts.

However, there are some geological issues with this explanation. First and foremost, the two ends of the canyon seem to be different ages. In fact, the eastern part of the canyon is thought to be much older than the western part, which many think was created in more recent times, speaking in geological terms that is. According to recent studies, the western end is more around 700,000 years old, making it relatively new from a geological perspective (University of Arizona, 2002). In the west end of the canyon, "local sediments come from the Basin and Range area to the west of the Canyon and are from Miocene layers. No river could have carved through there until after the Miocene" era, which suggests that this part of the canyon was formed relatively recently, or at least years after the eastern part of the canyon (Missler, 2011). The eastern end is, however, much older, around 5-7 million years old according to recent geological findings (University of Arizona, 2002). Moreover, there is a lack of evidence suggesting that an ancient Colorado River actually ran through the Grand Wash Cliffs at the far western portion of the canyon, suggesting that there may have been an "upper Colorado River system to the east that did not originally continue west of the Colorado Plateau" (Missler, 2011). Clearly, there are some major issues with this commonly held...

From this perspective, a breach of a natural damn caused ancient lakes to rush into the region, carving out the canyon in a violent fury. To the east of the Grand Canyon, there is an area known as the Bidahochi Formation, which is thought by many to be the site of two ancient and massive lakes that were sealed off by a natural damn. Geologists began uncovering evidence of lava dams present in and around the Colorado River as early as 1882. The area around the Grand Canyon is a hotbed for volcanic activity, and many of the rock layers in and around the canyon are lava sediments, coming directly from lava flows from volcanoes. There are also the Hurricane and Toroweap faults, which are some of the most active faults in all of Arizona (University of Arizona, 2002). Lava dams are notoriously unstable for a number of reasons. First and foremost, "these lava dams were inherently unstable because molten basalt met cold river water and rapidly cooled, forming fragile walls of glass" (University of Arizona, 2002). This means that they are not as strong as other sediment dam structures and can have fractures that would allow for both a slow wearing away and a massive breach all at once. According to one report, many believe that "these dams -- formed when lava from volcanoes on the rim flowed into the canyon -- were slowly worn away as water flowed over them" (University of Arizona, 2002). Yet, this slowly washing away would not have provided enough water pressure for a huge burst to sketch out the Grand Canyon. This fact is what held many back from assuming it was a dam breach that caused the formation of the Grand Canyon. Yet, in modern studies, "geologists have found evidence that some of these dams did not slowly waste away. Instead, some burst catastrophically -- in one case unleashing a massive flash flood carrying 37 times more water than the largest ever recorded on the Mississippi River" (University of Arizona, 2002). This massive flood caused millions of gallons of pressured water to rush into the lower lying regions of the canyon, tearing away the limestone and opening new channels for the Colorado River and its tributaries to flow.
The known existence of lava dams in the past then leads credence to the possibility of a lava dam breach as the original cause of the gutting of the Grand Canyon. In the eastern part of the Park, the Colorado River had already been at work etching out canyons in the soft limestone. However, the canyon was increased in size on the western end after a catastrophic natural event. Those who promote this theory believe that "the Colorado did not really cause the Grand Canyon at all; it merely followed the easiest path down to the Sea of Cortez after the canyon had been formed" (Missler, 2011). According to this alternate theory, the natural dam holding back the massive ancient lakes broke after some degree of flooding. Thus, water from these enormous lakes gushed down into the low-lying areas below the Colorado Plateau and carved out the beginning trenches of what would later become the Grand Canyon (Meek & Douglass, 2001). Since the canyon is made of soft limestone, this initial rush of water out has carved out gashes in the rock. It has been proven before that "Large sustained floods can cause rapid downcutting in bedrock" (University of Arizona, 2002). Thus, the theory that a massive flood caused by a breach in a natural lava dam may have provided enough water and force to cut out the beginning framework of the Grand Canyon. Modern geologists believe the catastrophic dam breach occurred around 165,000 years ago, based on the sediment debris around the rock layers of that time. The event was so dramatic that it actually changed the original flow path of the Colorado River. After this happened, the Colorado then began flowing through the area now known as the Grand Canyon and eventually began its own process of erosion in the region, cutting out the soft limestone as it continued to find new paths southwards towards the ocean. Rivers will naturally follow the path of least resistance to the closest ocean and as the dam break caused new fishers in the limestone, the Colorado eventually found a new path to the Sea of Cortez (Meek…