With canyons, waterfalls, rivers, forests and mountains, Yellowstone National Park showed us the beauty of this planet. The park also happens to be the largest mega-fauna location in the Continental United States. And it did not disappoint on that account either. The range of wildlife we saw exceeded our expectations and included a black bear with her cub, wolves, mountain goats, coyote, both mule deer and bull elk, bison and many other interesting animals and birds.
But the most incredible aspects of our exploration were the geological wonders contained within the park.
The most awe-inspiring geyser of all is known as “Old Faithful,” which spouts boiling water and steam about 45 m (150 feet) out of the ground every one to two hours. We sat a safe distance from the geyser as the boiling water ran past where we sat. We watched as it built up its pressure, akin to a massive pressure cooker, teasing us until suddenly boiling water and steam streamed high and wide for five minutes before dying back.
On our left other smaller geysers were spouting at the same time. We were astounded to witness this otherworldly spectacle. We were made acutely and disturbingly aware of the ominous heat that was so close below the Earth’s crust.
The whole area had been created by a super volcano, and is still classified as active. The lava forms most of the mountains and canyons. Initially, we assumed that a super volcano described a larger than normal volcano but we learned that a super volcano is entirely different.
In a typical volcano, magma (molten rock) pushes itself to the surface, usually after a landslide, through a “chimney” followed by lava flows from the crater and gradually forms the volcano’s typical conical mountain. At the same time, volcanic ashes are thrown by the gases from the magma that escape into the air.
With a super volcano everything is different. In this instance the rising basaltic magma forms a massive pocket that pushes upwards on the Earth’s crust, stretching it. The height of the caldera is rising by approximately 8 cm (3 inches) per year as a result of the stretching of the Earth’s crust. In the case of Yellowstone’s magma pocket, it’s 89 km long (55 miles), 32 km wide (20 miles) and between 5 and 11 km deep (3 and 7 miles).
This is 2.5 times larger than previously thought, not because it had suddenly expanded, but because only recently were the scientific instruments available to accurately measure its size. This is close to the size of the pocket when the super volcano last erupted. Areas where the magma is closest to the Earth’s surface also match up to the fiercest hydro-thermal activity. It was previously believed that Yellowstone’s magma pocket was a series of smaller connected pockets.
The massive crater created by previous eruptions is known as a caldera and the Yellowstone caldera is classed as an active volcano. It has erupted with tremendous force several times in the last 2 million years, the latest being 640,000 years ago. Half of the world’s geothermal features are in Yellowstone, (500 out of 1,000 globally), fuelled by this ongoing volcanism.
We asked the guide if it was known how long it might be before the super volcano next erupted. He dryly replied, “All we know is we are one day nearer.”
Lava flows and rocks from volcanic eruptions cover much of the area of Yellowstone, forming a 48-by-72 km basin (30-by-45 miles). The park is the centrepiece of the greater Yellowstone eco system, the largest remaining nearly intact eco system of the Earth’s northern temperate zone.
There are also large areas that resemble some alien planet. In those areas the magma of molten rock lies only 2 miles below the surface with hot sulphurous mud and springs boiling and bubbling. The most striking of these areas, named Porcelain Springs, is truly mind-blowing to witness. Many people die each year by ignoring the many signs warning of the intense heat (93 degrees C [200 degrees F] or more) if they leave the raised walkways and step on the surface below.
The huge vista of uninhabitable alien landscape brought home to us the dangers of piercing the Earth’s crust and how perilous fracking is to the planet.
The dangers of fracking
Fracking (hydraulic fracturing) is the process of injecting liquid at high pressure into subterranean rocks, boreholes and existing fissures so as to force open existing and newly created fissures and extract oil and gas. The liquid that’s injected comprises a mixture of water, sand and chemicals. Apart from the possible catastrophic risks from piercing the Earth’s crust, there are real risks of polluting underground water supplies. There are reports of significant pollution of water from natural underground reservoirs, including ignitable gas, coming through household faucets. As far as we’re aware, such pollution has not been officially validated, or perhaps just not brought to the public’s attention.
What fracking could look like
We were horrified by the sight of the Porcelain Springs because we were looking at the possible shape of things to come, of how huge areas of our planet might look if fracking continued unabated. Life cannot be sustained in the environment of such high temperatures, sulphur fumes and bubbling mud mixed with colourful minerals. It was a shocking experience to be shown what could happen anywhere on our planet when the magma is released close to or through the Earth’s crust, whether through man-made fracturing or through nature itself.