English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Knowledge of the stability of carbonate minerals at high pressure is essential to better understand the carbon cycle deep inside the Earth. The evolution of Raman modes of carbonates with increasing pressure can straightforwardly illustrate lattice softening and stiffening. Here, we report Raman modes of natural magnesite MgCO 3  up to 75 GPa at room temperature using helium as a pressure-transmitting medium (PTM). Our Raman spectra of MgCO 3  show the splitting of  T  and ν 4  modes initiated at approximate 30 and 50 GPa, respectively, which may be associated with its lattice distortions. The MgCO 3  structure was referred to as MgCO 3 -Ib at 30–50 GPa and as MgCO 3 -Ic at 50–75 GPa. Intriguingly, at 75.4 GPa some new vibrational signatures appeared around 250–350 and ~800 cm –1 . The emergence of these Raman bands in MgCO 3  under relatively hydrostatic conditions is consistent with the onset pressure of structural transition to MgCO 3 -II revealed by theoretical predictions and high-pressure and high-temperature experiments. This study suggests that hydrostatic conditions may significantly affect the structural evolution of MgCO 3  with increasing pressure, which shall be considered for modeling the carbon cycle in the Earth’s lower mantle.

Raman signatures of the distortion and stability of MgCO 3 to 75 GPa