For centuries, scientists have been perplexed by the inability to grow dolomite, a common mineral found in various geological formations, in the laboratory under conditions believed to mimic its natural formation. Dolomite is abundant in rocks older than 100 million years but conspicuously absent in younger formations, leading to the geological mystery known as the “Dolomite Problem.” However, thanks to new atomic simulations and a groundbreaking theory, researchers from the University of Michigan and Hokkaido University in Japan have finally achieved success in growing dolomite in a laboratory setting.
The key to successfully growing dolomite lies in understanding and addressing the defects that hinder its crystal structure formation. In the natural growth of minerals, atoms typically deposit neatly onto the growing crystal surface. However, dolomite’s growth edge consists of rows of calcium and magnesium, which often attract and attach randomly, creating defects that impede further dolomite layer formation. This disorder significantly slows down dolomite growth, making it a sluggish process that would take millions of years to form just one layer of ordered dolomite.
Fortunately, these defects are not permanent. Less stable than atoms in the correct position, the disordered atoms are the first to dissolve when the mineral is washed with water, such as through rainfall or tidal cycles. This repeated rinsing effectively removes these defects, allowing dolomite layers to form in a matter of years. Over time, this process contributes to the accumulation of dolomite mountains seen in various regions.
To accurately simulate dolomite growth, the research team needed to calculate the strength of atoms’ attachment to an existing dolomite surface. Achieving the most precise calculations would require an exhaustive assessment of every single interaction between electrons and atoms within the growing crystal, a computationally demanding task. However, the team found a shortcut using software developed at the University of Michigan’s Predictive Structure Materials Science (PRISMS) Center.
This software employs initial energy calculations for specific atomic arrangements and extrapolates to predict energies for other arrangements based on the crystal structure’s symmetry. This shortcut significantly reduces the computing power required for the simulations. Instead of thousands of CPU hours on a supercomputer, these calculations can now be performed in just milliseconds on a desktop. This breakthrough in computational efficiency allowed the team to simulate dolomite growth over geologic timescales.
While the evidence from intermittent dolomite formation in certain areas aligns with the researchers’ theory, it was necessary to validate their findings experimentally. Yuki Kimura, a materials science professor at Hokkaido University, and Tomoya Yamazaki, a postdoctoral researcher, conducted tests using transmission electron microscopes. Interestingly, instead of using electron beams solely for imaging, these beams were utilized to split water, generating acid that dissolves the dolomite crystals.
By placing a small dolomite crystal in a calcium and magnesium solution and pulsing the electron beam 4,000 times over two hours, Kimura and Yamazaki observed the dissolution of defects and subsequent growth of dolomite. Although the growth yielded approximately 300 layers of dolomite, a significant increase from previous attempts, this breakthrough demonstrates the potential to grow dolomite in the lab for further study and application.
Beyond solving the enigma of dolomite growth, the research findings hold promise for the advancement of various technological materials. The lessons learned from the Dolomite Problem can provide engineers with insights into manufacturing higher-quality materials in fields such as semiconductors, solar panels, and batteries. Traditionally, crystal growers aimed to achieve defect-free materials by growing them slowly. However, the breakthrough in dolomite growth suggests new strategies for promoting the crystal growth of modern technological materials.
The successful laboratory growth of dolomite represents a breakthrough in our understanding of mineral formation. By addressing and removing defects, scientists have overcome the countless failures and challenges faced over the past two centuries. This achievement not only solves the long-standing Dolomite Problem but also opens doors to innovative approaches in manufacturing advanced materials. The future of mineral growth and its applications in various industries is now brighter than ever.
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