Modern Australian
The Times Real Estate

.

after 1.5 billion years in flux, here's how a new, stronger crust set the stage for life on Earth

  • Written by Fabio A Capitanio, Lecturer in Geophysics, Monash University

Our planet is unique in the Solar system. It’s the only one with active plate tectonics, ocean basins, continents and, as far as we know, life. But Earth in its current form is 4.5 billion years in the making; it’s starkly different to what it was in a much earlier era.

Details about how, when and why the planet’s early history unfolded as it did have largely eluded scientists, mainly because of the sparsity of preserved rocks from this geological period.

Our research, published today in Nature, reveals Earth’s earliest continents were entities in flux. They disappeared and reappeared over 1.5 billion years before finally gaining form.

Early Earth: a strange new world

The first 1.5 billion years of Earth’s history were a tumultuous period that set the stage for the rest of the planet’s journey. Several key events took place, including the formation of the first continents, the emergence of land and the development of the early atmosphere and oceans.

All of these events were the result of the changing dynamics of Earth’s interior. They were also catalysts to the first appearances of primitive life.

Zircon crystal This almost 4.4 billion-year-old zircon crystal, retrieved from Western Australia’s Pilbara region, is one of the oldest rock fragment ever found. In reality it’s smaller than the head of a pin. Author provided

The preserved record of Earth’s first 500 million years is limited to just a few tiny crystals of the mineral zircon. Over the next billion or so years, kilometre-long (and larger) fragments of rock were generated and preserved. These would go on to forge the cores of major continents.

Scientists know about the properties of rocks and the chemical reactions that must occur for their constituent minerals to be made. Based on this, we know early Earth boasted very high temperatures, hundreds of degrees hotter than today’s.

Read more: Earth's rock-solid connections between Canada and Australia contain clues about the origin of life

An epic metamorphosis

Earth’s crust today is made of thick, buoyant continental crust that stands proud above the sea. Meanwhile, below the oceans are thin but dense oceanic crusts.

The planet is also broken into a series of plates that move around in a process called “continental drift”. In some places, these plates drift apart and in other they converge to form mighty mountains.

This dynamic movement of Earth’s tectonic plates is the mechanism by which heat from its interior is released into space. This results in volcanic activity focused mainly at the plate boundaries. A good example is the Ring of Fire — a path along the Pacific Ocean where volcanic eruptions and earthquakes are frequent.

To unravel the processes that operated on early Earth, we developed computer models to replicate its once much hotter conditions. These conditions were driven by large amounts of internal “primordial heat”. This is the heat left over from when Earth first formed.

Diagram of Earth's structure Today, Earth has a silica-rich continental crust above sea level and a thin (but dense) silica-poor crust in the ocean. Shutterstock

Our modelling shows the release of primordial heat during Earth’s early stages (which was three to four times hotter than today’s) caused extensive melting in the upper mantle. This is the mostly solid region below the crust, between 10km and 100km deep.

This internal melting created magma which, through a plumbing system, was thrust out as lava onto the crust. The shallow mantle left behind, dry and rigid, became welded to the crust and formed the first continents.

The pulse of first life

Our research revealed a lag between the formation of Earth’s first crust and the development of the mantle keels at the base of the first continents.

The first formed crust, which was present between 4.5 billion and 4 billion years ago, was weak and prone to destruction. It progressively became stronger over the next billion years to form the core of modern continents.

This process was crucial to continents becoming stable. When magma was purged from Earth’s interior, rigid rafts formed in the mantle beneath the new crust, shielding it from further destruction.

Bands in rock representing early continental activity. Pictured is banded igneous rock built up from multiple layers of magma. This rock is from Western Australia’s Pilbara Region. Author provided

Moreover, the rise of these rigid continents ultimately led to weathering and erosion, which is when rocks and minerals break down or dissolve over long periods to eventually be carried away and deposited as sediment.

Early erosion would have changed the composition of Earth’s atmosphere. It would have also provided nutrients to the oceans, seeding the development of life.

From our observations, we conclude the breaking of Earth’s early crust was necessary to make way for a sturdier replacement. And had this not happened, we would not have the continents, nor life, as we know it.

Read more: Magnetism of Himalayan rocks reveals the mountains' complex tectonic history

Authors: Fabio A Capitanio, Lecturer in Geophysics, Monash University

Read more https://theconversation.com/the-floor-is-lava-after-1-5-billion-years-in-flux-heres-how-a-new-stronger-crust-set-the-stage-for-life-on-earth-151276

Taking It Up a Notch: How 12.5kg Dumbbells Fit Into Progressive Overload Training

Photo by Jason Grant on Unsplash When it comes to getting stronger, more sculpted, and better conditioned, one principle reigns supreme in the worl...

Behind the Bowl: What Makes Premium Dog Food Worth the Price Tag?

Photo by Ayla Verschueren on Unsplash When it comes to feeding our four-legged companions, the pet food aisle can be a maze of options—bags promi...

Davines Sustainable Haircare: Revolutionizing Eco-Friendly Beauty Solutions

Davines is a well-known brand in the world of haircare, known for its high-quality products that deliver exceptional results. Its commitment to sust...

The Role of CDNs in Enhancing Headless CMS Performance and Reliability

A headless CMS provides businesses with the ultimate freedom for content management and output possibilities across any number of channels. However...

Finding the Right Dentist in Perth for Your Dental Implants: A Complete Guide

Missing teeth can significantly impact your quality of life, affecting everything from your ability to eat and speak to your self-confidence. Dental...

Fix These 5 Technical SEO Issues Hurting Your Perth Business Rankings

Perth businesses face unique challenges when competing for visibility in local search results.  While many business owners focus on content creati...

How a Professional Bookkeeper Can Help Your Small Business

Running a small business in Australia comes with many responsibilities, from managing day-to-day operations to ensuring compliance with tax and fina...

How Pre-Employment Drug Testing Can Improve Your Company’s Culture

When it comes to curating a thriving workplace, culture is everything. It is the glue holding teams together, the driving force behind productivity...

How To Find Comfortable And Stylish Armchairs Online

Shopping online can be tricky, particularly when it comes to buying furniture. All homeowners, including you, want an armchair that is stylish and c...

Rope Rescue Training Explained: Techniques, Tools & Skills

Rope rescue training is critical for emergency responders, industrial workers, and anyone who operates in high-risk environments. Whether you're a fir...

The Different Career Paths in a Law Firm: From Clerk to Partner

The legal profession offers a structured yet diverse career path, with opportunities ranging from entry-level positions to esteemed leadership roles...

The Importance of Exercise for People with Disabilities: Adaptive Workouts

Exercise is a fundamental part of maintaining physical and mental wellbeing, and this holds true for people of all abilities. For individuals with d...

Planning a Construction or Renovation? Don’t Overlook the Plumbing!

Building or renovating your home is an exciting journey—designing layouts, selecting finishes, and watching your space come to life. However, while ...

Bathroom Tiling: Trends, Materials and Installation Tips

The world of bathroom tiling has come a long way, with new trends, improved materials, and innovative installation techniques, making it easier than...

Best Products to Increase Hair Density: What Really Works?

Do you want thick, voluminous hair? We get you!! There’s just something about a full head of hair that makes you feel more confident. But what do...

The Cost of Back to Base Security in Sydney: Is It Worth the Investment?

Sydney is a fantastic place to live. The beaches, the cafes, the culture. There’s a reason people are willing to pay premium prices for a spot in ...

Australian Workplace Engagement Declines Amidst Shifting Employee Priorities

Global leader in employee engagement and HR technology, Reward Gateway, has today released its second annual Workplace Engagement Index. The report...

The Right Mix: 5 Tips for Choosing Products Your Customers Will Love

Photo: Marcella Marcella / Unsplash Crafting the perfect product offering is difficult. You need to strike a delicate balance between building a busi...