The Times Australia
The Times World News

.
The Times Real Estate

.

Australia’s largest iron ore deposits are 1 billion years younger than we thought

  • Written by Liam Courtney-Davies, Postdoctoral Research Associate, University of Colorado Boulder

Iron ore is the key ingredient in steel production. One of the fundamental resources for the Australian economy, it contributes A$124 billion in national income[1] each year.

This is not surprising, considering Western Australia is home to some of Earth’s largest iron ore deposits, and 96% of Australia’s iron ore comes from this state. Yet despite the metal’s significance, we still don’t know exactly how and when iron deposits formed within the continent.

In new research published in the Proceedings of the National Academy of Sciences[2], we answer some of these questions by directly measuring radioactive elements in iron oxide minerals which form the basis of these resources.

We found that several of Western Australia’s richest iron deposits – such as Mt Tom Price and Mt Whaleback – are up to 1 billion years younger than previously understood. This redefines how we think about iron deposits at all scales: from the mining site to supercontinents. It also provides clues on how we might be able to find more iron.

A medium distance view of a weathered mountain with bands of rock clearly visible.
Punurrunha or Mt Bruce, part of the Hamersley Range in the Pilbara, Western Australia. Julie Burgher/Flickr, CC BY-NC[3][4]

Where does iron ore come from?

Billions of years ago, Earth’s oceans were rich in iron. Then early bacteria started photosynthesising and rapidly introduced huge amounts of oxygen into the atmosphere and oceans. This oxygen combined with iron in the oceans, causing it to settle on the sea floor.

Today, these 2.45-billion-year-old sedimentary rock deposits are called banded iron formations[5]. They represent a unique archive of the interactions between Earth’s continents, oceans and atmosphere through time. And, of course, banded iron formations are what we mine for iron ore.

These sedimentary deposits have distinctive, rhythmic bands of reddish iron and paler silica. They were alternately laid down on the sea floor seasonally. Such remarkable rocks can be visited today in Karijini National Park, WA.

A rusty red rock with darker bands of red visible throughout. Typical banded iron formation at Fortescue Falls in Kaijini National Park, Western Australia. Graeme Churchard/Wikimedia Commons, CC BY[6][7]

The iron content of these banded iron formations is generally less than 30%. For the rock to become economically viable to mine, it must be naturally converted by later processes to around 60% iron.

The nature of this rock conversion is still debated. In simplest terms, a fluid – such as water – will both remove silica and introduce more iron during an “upgrading” process which transforms the rock’s original makeup.

The geochronology (age dating) of this chemical transformation and upgrading is not well understood, largely because the tools required to directly date the iron minerals have only recently become available.

Previous age estimates for the Pilbara iron deposits were indirect but suggested they were at least 2.2 billion years old.

What did we find out?

You may think of iron ore as rusty, red-coloured dust. However, it’s typically a hard, heavy, steely-blue material. When crushed into a fine powder, iron ore turns red. So the red landscape we see across the Pilbara today is a result of the weathering of iron minerals from beneath our feet.

A gloved hand holding a round steely blue rock on a backdrop of reddish rocks. 1.3-billion-year-old steel blue iron ore extracted from Hamersley Province, Western Australia. Liam Courtney-Davies

We extracted microscopic scale “fresh” iron minerals from drill core samples at several of the most significant Western Australian iron deposits.

Leveraging recent advancements in radiometric dating, we measured naturally occurring radioactive elements in the rocks. In particular, the ratio of uranium to lead isotopes in a sample can reveal how long ago individual mineral grains crystallised.

Using the newly generated iron mineral age data, we constructed the first-ever timeline of the formation of Western Australia’s major iron deposits.

We discovered that all major iron ore deposits in the region formed between 1.4 and 1.1 billion years ago, making them up to 1 billion years younger than previous estimates.

These deposits formed in conjunction with major tectonic events, especially the breakup and reemergence of supercontinents. It shows just how dynamic our planet’s history is, and how complex the processes are that led to the formation of the iron ore we use today.

Now that we know that giant ore deposits are linked to changes in the supercontinent cycle, we can use this knowledge to better predict the places where we are more likely to discover more iron ore.

Liam Courtney-Davies completed this research while at John de Laeter Centre, Curtin University.

References

  1. ^ A$124 billion in national income (theconversation.com)
  2. ^ published in the Proceedings of the National Academy of Sciences (doi.org)
  3. ^ Julie Burgher/Flickr (www.flickr.com)
  4. ^ CC BY-NC (creativecommons.org)
  5. ^ banded iron formations (www.csiro.au)
  6. ^ Graeme Churchard/Wikimedia Commons (en.wikipedia.org)
  7. ^ CC BY (creativecommons.org)

Read more https://theconversation.com/australias-largest-iron-ore-deposits-are-1-billion-years-younger-than-we-thought-235089

The Times Features

Understanding the Dangers of Ignoring a Gas Leak

Gas leaks are silent threats lurking within both homes and workplaces. A gas leak occurs when natural gas or any other gaseous substance escapes from a pipeline or containment. T...

Can You Sell Your House Privately in Queensland? Here’s How

Selling a house privately in Queensland is entirely possible and can be a cost-effective alternative to using a real estate agent. While agents provide valuable expertise, their co...

Itinerary to Maximize Your Two-Week Adventure in Vietnam and Cambodia

Two weeks may not seem like much, but it’s just the right time for travelers to explore the best of Vietnam and Cambodia. From the bustling streets of Hanoi to the magnificent te...

How to Protect Your Garden Trees from Wind Damage in Australia

In Australia's expansive landscape, garden trees hold noteworthy significance. They not only enhance the aesthetic appeal of our homes but also play an integral role in the local...

Brisbane Homeowners Warned: Non-Compliant Flexible Hoses Pose High Flood Risk

As a homeowner in Brisbane, when you think of the potential for flood damage to your home, you probably think of weather events. But you should know that there may be a tickin...

Argan Oil-Infused Moroccanoil Shampoo: Nourish and Revitalize Your Hair

Are you ready to transform your hair from dull and lifeless to vibrant and full of life? Look no further than the luxurious embrace of Argan Oil-Infused Moroccanoil Shampoo! In a...

Times Magazine

"Eternal Nurture" by Cara Barilla: A Timeless Collection of Wisdom and Healing

Renowned Sydney-born author and educator Cara Barilla has released her latest book, Eternal Nurture, a profound collection of inspirational quotes designed to support mindfulness, emotional healing, and personal growth. With a deep commitment to ...

How AI-Driven SEO Enhancements Can Improve Headless CMS Content Visibility

Whereas SEO (search engine optimization) is critical in the digital landscape for making connections to content, much of it is still done manually keyword research, metatags, final tweaks at publication requiring a human element that takes extensiv...

Crypto Expert John Fenga Reveals How Blockchain is Revolutionising Charity

One of the most persistent challenges in the charity sector is trust. Donors often wonder whether their contributions are being used effectively or if overhead costs consume a significant portion. Traditional fundraising methods can be opaque, with...

Navigating Parenting Arrangements in Australia: A Legal Guide for Parents

Understanding Parenting Arrangements in Australia. Child custody disputes are often one of the most emotionally charged aspects of separation or divorce. Parents naturally want what is best for their children, but the legal process of determining ...

Blocky Adventures: A Minecraft Movie Celebration for Your Wrist

The Minecraft movie is almost here—and it’s time to get excited! With the film set to hit theaters on April 4, 2025, fans have a brand-new reason to celebrate. To honor the upcoming blockbuster, watchfaces.co has released a special Minecraft-inspir...

The Ultimate Guide to Apple Watch Faces & Trending Wallpapers

In today’s digital world, personalization is everything. Your smartwatch isn’t just a timepiece—it’s an extension of your style. Thanks to innovative third-party developers, customizing your Apple Watch has reached new heights with stunning designs...

LayBy Shopping