From Plate Tectonics to Black Smokers: Hutton’s Influence Today

 

Hutton’s ideas from the late 18^th century have led to some of the most important discoveries in geology!

Centuries ago, a man by the name of James Hutton was born. He grew up with an interest in just about everything science, normal for the time, but was captivated by geology. Many topics were still not well understood, geology was a relatively new science at the time, but one debate, one that had catastrophic consequences, was the debate over how marine fossils made it to mountaintops. This debate, and Hutton, had outcomes and ideas that led to most of the modern-day principles of geology. Hutton just may have been the most influential man in geology.

 

Hutton’s Original Idea’s: Ahead of His Time

 

Neptunists and Plutonists are the names given to the people who held a side in that debate. The Neptunists thought there were periods of great floods which covered the planet and that’s how marine fossils ended up on mountaintops. Plutonists thought that there were larger processes at play since they had observed volcanoes and earthquakes changing the Earth’s surface while not appearing to change the seas. They also countered the Neptunists by saying something along the lines of “well where does all the water go when in a period without a great flood?”

           

How does this relate to Hutton you might ask? Well Hutton was thinking about this very argument when he was struck with a realization; the soil on his farm was the result of erosion on rocks. That erosion then gets washed into a stream or river and gets carried further into the ocean. It couldn’t end there though he thought, or Earth would end up smooth over time, so Hutton concluded that Earth must also have some sort of uplift which creates hills and mountains. And what makes these new rocks that are to be uplifted? He thought Earth’s interior must use heat to create new rocks which get brought to the surface by this uplift and that those marine fossils must have risen with the land over time NOT been deposited by a great flood.

           

These ideas were phenomenal, huge discoveries, but nobody believed him. In his first paper in 1785 nobody even listened to him because he couldn’t communicate these ideas in a comprehensible way. With some encouragement, he published an expanded version of the paper into two books a decade later, and it had the same result. Hutton died not getting the respect he deserved for his ideas, but luckily his close friend John Playfair simplified Hutton’s ideas into a new book entitled Illustrations of the Huttonian Theory of the Earth. This book, published in 1802, was received positively and did Hutton justice, but there was still no proof for all his ideas.

 

Holmes’s Continental Drift

 

Before Arthur Holmes made his now famous theory there was a debate occurring on the soundness of what would later be known as continental drift. In 1908, a man named Frank Bursley noticed that the eastern coastline of North America and South America fit the west side of Europe and Africa respectively, like many had noticed, and theorized that continents had once slid around and their collisions could be the cause of mountain chains. Unfortunately, his idea was not taken seriously due to lack of evidence.

           

This is where Alfred Wegener came in. He took Bursley’s idea and added on to it. One observation he made was that fossils to particular species could be found in specific continents across the Atlantic Ocean. He also noticed present day marsupials are in the Americas and Australia but nowhere else, and a species of snail is in New England and Scandinavia which is across the whole ocean. With this he also noticed coal seams could be found in frigid locations where a tropical ecosystem couldn’t have been without some form of drift.

           

This led to him theorizing that a supercontinent, named Pangaea, once existed. He published his first work in 1912, and an expanded edition in 1920 which got more attention. It caused much discussion, but still didn’t explain HOW the continents moved around. It wasn’t until Arthur Holmes, the man who determined the age of the Earth (most accurately for his time, but not accurate by today’s estimate), that an explanation was proposed. Holmes published his continental drift theory in 1944 which states that radioactive warming could cause convection currents within the Earth causing the continents to be able to move about.

 

The Emergence of Plate Tectonics

 

The last step to reaching plate tectonics comes mainly from Harry Hess. This man was in WWII as leader of an attack transport ship that contained a depth sounder called a fathometer. He used this to check out the seafloor and found that it is much more barren than it should be if it’s ancient. It was soon discovered the largest mountain range was underwater ranging along the middle of the Atlantic both north and south. In 1960 core samples were taken in the Atlantic Ocean and it showed the ages of rocks being youngest closest to the mountain range (Mid-Atlantic Ridge) and older as you went further away.

           

This taught Hess something important: new rock is being made in these underwater mountain ranges (or rifts) and it is pushing the seafloor apart. He later called this seafloor spreading. As oceanic crust met continental crust it went under it, or subducted, and the sediments were returned to Earth’s interior to be recycled. After more studies were done showing confirmation for continental drift, ones with rocks containing magnetic ores, it was finally accepted as an accepted theory and was renamed plate tectonics in 1968 due to plates not just containing land mass but oceans too.

 

Hydrothermal Vents: A New Ecosystem

 

With the explanation of seafloor spreading and subduction you know how new rock is made and old rock recycled. What may have been misleading is that many minerals and elements can come up in ways other than rock formation. In seafloor spreading zones there are structures called black smokers which look like they are releasing a continuous stream of black smoke, hence the name. These structures were first discovered and described in 1977 near the Galapagos Islands and what they do is push up particle-ridden water releasing mostly sulfides into the water.

           

Most of these sulfides are metal containing like iron sulfide which gives it the black color. If you go further from the spreading zone you can actually find white smokers as well which release compounds like calcium, barium, and silicon. What’s important about these is they somehow support life. In fact, many think hydrothermal vents could have been what started life on this very planet. Research at these vents has been a very popular thing in the past decades.

 

Using Hydrothermal Vents for Egg Incubation

 

Ah we finally made it to the end. We started with Hutton theorizing Earth processes, going over how some of those were proven and expanded upon over the years, and leaving off on hydrothermal vents possibly starting life. How does this tie into recent discoveries though? Well recent research has shown that a new species of marine animal, the deep-sea skate (Bathyraja spinosissima), uses these hydrothermal vents, a volcanic source by definition, to incubate their eggs. No other marine animal has been discovered which does this which shows just how important hydrothermal vents are.

           

And where would we be on understanding hydrothermal vents if Hutton hadn’t started us off on this journey? Maybe someone else would have filled in his place and we’d be in the same place, who knows? What I can say for sure is this is an interesting world with lots to discover. With new discoveries being made every year in the sciences what do you think will come next? Will we drill into the mantle? Will we land a man on Mars? Will we explore the rest of the seafloor? Let me know what you think in the comments below.

 

References

Salinas-de-León, P., Phillips, B., Ebert, D. et al. Deep-sea hydrothermal vents as natural egg-           case incubators at the Galapagos Rift. Sci Rep 8, 1788 (2018).            <https://doi.org/10.1038/s41598-018-20046-4/>

Bryson, Bill. A Short History of Nearly Everything. Broadway Books, 2003.

Döme, Laci. 11 March 2016. pixabay. Photo. <https://pixabay.com/photos/mountains-alps-trees-1244132/>.

NOAA. What is a hydrothermal vent? 26 February 2021. <https://oceanservice.noaa.gov/facts/vents.html#:~:text=Scientists%20first%20discovered%20hydrothermal%20vents,had%20never%20been%20seen%20before>.

Normark, W.R. and Dudley Foster. “Hydrothermal vent.” 1 January 1981. Wikipedia. <https://en.wikipedia.org/wiki/Hydrothermal_vent#/media/File:BlackSmoker.jpg>.

WHOI. Study Tests Theory that Life Originated at Deep Sea Vents. 9 April 2014.             <https://www.whoi.edu/press-room/news-release/study-tests-theory-that-life-originated-          at-deep-sea-vents/>.

Wikipedia. Hydrothermal vent. 5 April 2021.             <https://en.wikipedia.org/wiki/Hydrothermal_vent#Black_smokers_and_white_smokers>            .