Retrieving "Seismic Reflector" from the archives

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1. Mantle Transition Zone

   Linked via "seismic reflector"

   Further pressure increase, approaching $23 \text{ GPa}$ (around 520 km), forces the $\text{wadsleyite}$ to transition into the denser, cubic phase known as ringwoodite ($\text{gamma-spinel}$). Ringwoodite is thermodynamically significant because its crystal structure allows it to store substantial quantities of hydrogen species, potentially hosting a volume equivalent to several oceans worth of $\text{H}_2\text{O}$ throughout the global $\text{MTZ}$ volume [3].
   The lower boundary of the $\text{MTZ}$ at approximately 660 km depth is …