Meteorite findings reshape theories on Earth's missing elements

Meteorite findings reshape theories on Earth's missing elements
by Clarence Oxford
Los Angeles CA (SPX) Feb 06, 2025
The origins of Earth's essential elements-and the absence of certain key components-have long perplexed scientists. A recent study led by Arizona State University is now challenging established theories, offering a fresh perspective on planetary formation.

Conducted by ASU Assistant Professor Damanveer Grewal, alongside researchers from Caltech, Rice University, and MIT, the study examines the distribution of moderately volatile elements (MVEs) such as copper and zinc, which are crucial for planetary chemistry and life-sustaining conditions. Their findings, published in Science Advances, provide critical insights into why Earth and Mars contain fewer MVEs compared to primitive meteorites, known as chondrites.

Researchers analyzed iron meteorites-fragments of the metallic cores of ancient planetary building blocks-to uncover new data that contradicts prior theories. "We found conclusive evidence that first-generation planetesimals in the inner solar system were unexpectedly rich in these elements," Grewal stated. "This discovery reshapes our understanding of how planets acquired their ingredients."

Previously, scientists theorized that MVEs were either unable to fully condense in the early solar system or were lost during planetesimal differentiation. However, this study suggests an alternative explanation: many of the first planetesimals actually retained MVEs, meaning Earth and Mars lost these elements later due to violent cosmic impacts that shaped their formation.

The study found that several inner solar system planetesimals preserved chondrite-like MVE abundances, implying they initially accumulated and retained these elements despite undergoing differentiation. This suggests that Earth and Mars were not born depleted in MVEs but instead experienced their loss over time due to intense collisional growth rather than incomplete condensation or early differentiation processes.

"Our work redefines how we understand the chemical evolution of planets," Grewal explained. "It shows that the building blocks of Earth and Mars were originally rich in these life-essential elements, but intense collisions during planetary growth caused their depletion."

Research Report:Enrichment of Moderately Volatile Elements in First-Generation Planetesimals of the Inner Solar System