The Earth breathes beneath us. The massive migrations of plate tectonics accompanied by other natural processes can lead to depths inconceivable from the comfort of your living room. Luckily, other adventurous souls have journeyed toward the center of the Earth to observe and document the deepest places on Earth.
TauTona Mine, South Africa
TauTona means “great lion” in Setswana, and TauTona mine in Johannesburg lives up to its namesake by virtue of size and terror. Around 500 miles of tunnels crisscross within the mine, extending as far as 2.4 miles deep into the Earth. These shafts are so deep that temperature rise to levels dangerous for humans. At its hottest points, air temperature can rise to 131 degrees Fahrenheit while rock face temperature can reach 140° F.
To circumvent these conditions, the AngloGold Ashanti company pumps ice-slurry and salt into the mine to be spread by fans for cooling. The cooling system consumes 6,000 tons of ice daily. However, even these measures are not sufficient to eliminate risk to human lives as death and injury are common for miners at TauTona. The massive infrastructure and tremendous danger that miners place themselves in all revolves around a 30-inch-wide seam of gold ore extending deep into the ground.
Lake Baikal, Russia
Lake Baikal in Southern Russia is both the largest freshwater lake on the planet, as well as the deepest. Baikal drops 5,387 feet, with its bottom at an altitude of 3,893 feet below sea level. Not only is Baikal the deepest lake in the world, but it continues to reach ever-deeper. The lake’s topography is a result of its location at a continental rift zone. As the plates move apart, the lake continues to deepen through subsidence. The plates at the rift zone, on which Baikal is situated, continue to drift apart at a rate of an inch per year.
Yarlung Tsangpo Grand Canyon, Tibet
The Yarlung Tsangpo Grand Canyon in Tibet is both the longest and deepest canyon in the world. Beginning near Mount Kailash, Yarlung Tsangpo Canyon stretches from Mount Namcha Barwa to the Himalayas with a length of around 150 miles. It has an average depth of 7,440 feet with its deepest point extending to 19,714 feet. Given the vast terrain and altitudes of the canyon, it comprises a number of different climates from subtropical to arctic. It also houses a number of rare species that have experienced minimal human contact, including the takin.
Canyons are generally formed via plate tectonics, but that isn't all that's going on with Yarlung Tsangpo. While plate tectonics can explain some of the abrupt land rise over 3 million years ago, it's not the sole cause of the canyon's depth. The uplift blocked flow from the Yarlung Tsangpo river that runs through the canyon. Over time, water pooled up in the natural dam, until overflow drove it over the edge of the steep uplift. The impenetrable depths of the Yarlung Tsangpo were created by water erosion from this runoff.
The Mariana Trench
Far beyond the sound of crashing waves or the rays of the sun, 36,000 feet beneath sea level, lies the Mariana Trench, the deepest point on the Earth's seafloor. The Mariana Trench is a subduction zone, formed from the migration of one tectonic plate beneath another. In the case of the Mariana Trench, the Pacific plate is submerged beneath the Mariana plate. When tectonic plates first begin to submerge, the sloping angle is gentle. However, over time, tectonic forces drive the trench to a near-vertical angle. The seafloor at the Mariana trench is over 180 million years old, giving nature plenty of time to drive the plates deeper and deeper. In addition, the trench is far removed from a major landmass, which precludes sediment runoff that would usually fill the trench. Finally, the topography of the Pacific plate forms a narrow taper that drives beneath the Mariana like a bottle opener.
For many years, it was believed that life within the ocean could not sustain itself beyond a certain depth coined the azoic. This hypothesis was based on the absence of sunlight to fuel photosynthesis in tandem with high pressure and low oxygen. However, in 1864, the Norwegian naturalist Michael Sars dredged a stalked crinoid (Rhizocrinus lofotensis) from a depth of 550 meters below sea level disproving the hypothesis. Nearly a century later, in 1960, Navy Lt. Donald Walsh and Jacques Piccard boarded the bathyscaphe “Trieste.” After a little under five hours, the Trieste was 35,810 feet below sea level at a pressure of 17,000 lbs/in2. Piccard and Walsh ate candy bars and shined a light into the Mariana Trench, where they observed an odd-looking creature that resembled a shrimp.
Testament to Life
While the deepest places on Earth are undoubtedly scientific marvels, they're also full of mystery and life. Even the mines of TauTona house a single bacterial species capable of withstanding the extremities and scarcity of the biome. The discovery of creatures in the deepest places on Earth is a testament to the marvels of adaptation and life's persistence. Wherever there exists the faintest chance of survival, there are living creatures scuttling across the depths.