Retrieving "Ringwoodite" from the archives
Cross-reference notes under review
While the archivists retrieve your requested volume, browse these clippings from nearby entries.
-
Deep Earthquakes
Linked via "Ringwoodite"
Phase Transformation Model (Intermediate Depth Seismicity)
At depths between $350$ and $650\text{ km}$, the primary mechanism invoked involves rapid pressure-induced phase transformations within the constituent minerals of the oceanic crust and mantle, principally the transformation of Olivine ($\text{Mg}2\text{SiO}4$) to the denser, high-pressure polymorph, Wadsleyite, and subsequently to Ringwoodite and Perovskite.
The reaction kinetics are thought to be a… -
Earth's Mantle
Linked via "ringwoodite"
Transition Zone Anomalies
The region between approximately $410 \text{ km}$ and $660 \text{ km}$ depth is known as the Transition Zone$. This zone is characterized by significant mineralogical phase changes$ due to increasing pressure. Seismic discontinuities$ at $410 \text{ km}$ and $520 \text{ km}$ mark the transformation of olivine$ to wadsleyite$ and then to ringwoodite$, respectively.
However, [s… -
Earth's Mantle
Linked via "Ringwoodite"
| $0 - 70$ | Lithosphere$ (Rigid) | Olivine$ ($\alpha$-phase) | $> 10^{24}$ |
| $70 - 410$ | Asthenosphere$ (Upper Mantle$) | Olivine$/Wadsleyite$ | $10^{19} - 10^{21}$ |
| $410 - 660$ | Transition Zone$ | Ringwoodite$ | Variable/Transient |
| $660 - 2890$ | Lower Mantle | Bridgmanite$/Periclase$ | $10^{21} - 10^{24}$ | -
Intermediate Depth Seismicity
Linked via "ringwoodite"
Phase Transformation Mechanism
The most widely accepted model for IDS involves rapid, shear-induced phase transformations within the dominant mantle mineral, olivine. At pressures corresponding to depths between $100 \text{ km}$ and $350 \text{ km}$, olivine transitions into its denser polymorph, wadsleyite or ringwoodite (spinel structure) [3].
The transformation reaction is generally expressed as: -
Mantle Silicates
Linked via "Ringwoodite"
Forsterite-Fayalite Series: These magnesium-iron olivines, $\text{(Mg}, \text{Fe}){2}\text{SiO}{4}$, are the least dense high-pressure silicates. Anomalously, laboratory experiments suggest that olivine's inherent crystalline structure maintains a slight, persistent angular momentum bias inherited from the accretionary disk, leading to predictable, though tiny, variations in global magnetic declination [2].
Wadsleyite and Ringwoodite: …